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Bulletin of the

British Museum (Natural History)

LIBRARY ,

Zoology series Vol 44 1983

British Museum (Natural History)
London 1983

Dates of publication of the parts

No 1 27 January 1983

No 2 24 February 1983

No 3 31 March 1983

No 4 28 April 1983

No 5 26 May 1983

No 6 30 June 1983

ISSN 0007-1 498

Printed in Great Britain by Henry Ling Ltd, at the Dorset Press, Dorchester, Dorset

Contents
Zoology Volume 44

Page

No 1 Observations on the systematics of the genus Difflugia in Britain
(Rhizopoda, Protozoa).
By Colin G. Ogden 1

No 2 Miscellanea

Cirolana cranchi Leach, 1818 (Crustacea: Isopoda: Cirolanidae)

redescribed, with notes on its distribution.

By N. L. Bruce & Joan Ellis 75

Valettieta, a new genus of deep-sea amphipod (Gammaridae: Lysia-
nassidae) with descriptions of two new species from the North
Atlantic Ocean.
By Roger J. Lincoln & Michael H. Thurston . . . .85

Three new genera of misophrioid copepods from the near-bottom

plankton community in the North Atlantic Ocean.

By G. A. Boxshall 103

Larval development of British prawns and shrimps (Crustacea:
Decapoda: Natantia) 4. Palaemon (Palaemon) serratus (Pennant,
1777) and functional morphology of swimming.
By A. A. Fincham . T ...... 125

The larval development of the Angular Crab, Goneplax rhomboides

(Linnaeus) (Decapoda: Brachyura).

By R. W. Ingle & P. F. Clark 163

The larval and first crab stages of three Inachus species (Crustacea:

Decapoda: Majidae); a morphological and statistical analysis.

By Paul F. Clark 179

No 3 A review of the Euplotidae (Hypotrichida, Ciliophora).

By Colin R. Curds & Irene C. H. Wu 191

No 4 The Opthalmotilapia assemblage of cichlid fishes reconsidered.

By Peter Humphry Greenwood . . . . . 249

No 5 Osteology, genitalia and relationships of the Acanthodactylus (Rep-
tilia: Lacertidae).
By E. N. Arnold 29 1

No 6 Morphological studies on some Difflugiidae from Yugoslavia (Rhi-
zopoda, Protozoa).
By Colin G. Ogden & Andjelija Zivkovic . 341

Bulletin of the

British Museum (Natural History)

Observations on the systematics of the
genus Difflugia in Britain (Rhizopoda,
Protozoa)

Colin G. Ogden

Zoology series Vol 44 No 1 27 January 1983

The Bulletin of the British Museum (Natural History), instituted in 1949, is issued in four
scientific series, Botany, Entomology, Geology (incorporating Mineralogy) and Zoology, and
an Historical series.

Papers in the Bulletin are primarily the results of research carried out on the unique and
ever-growing collections of the Museum, both by the scientific staff of the Museum and by
specialists from elsewhere who make use of the Museum's resources. Many of the papers are
works of reference that will remain indispensable for years to come.

Parts are published at irregular intervals as they become ready, each is complete in itself,
available separately, and individually priced. Volumes contain about 300 pages and several
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the series on either an Annual or Per Volume basis. Prices vary according to the contents of
the individual parts. Orders and enquiries should be sent to:

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British Museum (Natural History),
Cromwell Road,

London SW7 5BD,
England.

World List abbreviation: Bull. Br. Mus. nat. Hist. (Zool.)

Trustees of the British Museum (Natural History), 1983

The Zoology Series is edited in the Museum's Department of Zoology
Keeper of Zoology : Dr J. G. Sheals
Editor of Bulletin : Dr C. R. Curds

Assistant Editor: Mr C. G. Ogden

ISSN 0007- 1 498 Zoology series

Vol 44 No 1 pp 1-73
British Museum (Natural History)
Cromwell Road
London SW7 5BD Issued 27 January 1983

Observations on the systematics of the genus
Difflugia in Britain (Rhizopoda, Protozoa).

F GENERAL

28 JANW83

^4L

Colin G. Ogden

Department of Zoology, British Museum (Natural History), Cromwell Road, London
SW7 5BD

Contents

Synopsis

Introduction

Materials and methods

Systematic descriptions

Pyriform and elongate species . . . .

Pointed species or those with protruberances .

Ovoid or spherical species

Compressed species

Discussion

References

Index .

1
1

2
2
2

27
45
59
66
69
73

Synopsis

Detailed descriptions of the shell structure in thirty-eight species of Difflugia are given, and
further information on one species which has been redescribed in an earlier report (Ogden &
Fairman, 1979) is included. Two new species, Difflugia hiraethogii and D. stoutii, are described,
and other systematic changes include the following new combinations: D. cylindrus (Thomas,
1953), D. lacustris (Penard, 1899), D. microclaviformis (Kourov, 1925), D. microstoma (Thomas,
1954), D. parva (Thomas, 1954), D. tennis (Penard, 1890), D. tricornis (Jung, 1936), D. venusta
(Penard, 1902) and D. distenda nom, nov., D. gassowskii nom, nov., D. paulii nom. nov., D. rotunda
nom. nov. Seventeen of these redescriptions are new records for the British Isles. The structure of the
shell is discussed and the patterning of the organic cement which binds the particles together is shown to
be a useful taxonomic character.

Introduction

The taxonomy of specimens belonging to the genus Difflugia is based mainly on
differences in size and shape of the agglutinated shells constructed by these animals.
Comparison of cytoplasmic features are either difficult or impossible because most
of it is encased by the shell which is often opaque. Differences in the shell features
have resulted in about three hundred named species, varieties and forms being
currently attributed to the genus. This proliferation of species is due to a combination of the
lack of good diagnostic features and inadequate descriptions. The problem is clearly shown
in the only comprehensive survey of the genus, based on African specimens, by Gauthier-
Lievre and Thomas (1958). In this work the authors had difficulties with several groups of
individuals which shared common features, and as a result, about half of the 129 species
described were designated as varieties or forms.

Some earlier studies (Ogden, 1979, 1980; Ogden & Fairman, 1979) were con-
cerned with the variation of specimens having a pyriform shell, and the surface

Bull. Br. Mus. nat. Hist. (Zool.)44 (1): 1-73

Issued 2 7 January 1983

2 C. G. OGDEN

ultrastructure as revealed by the scanning electron microscope. The results showed
that there was usually a limited variation in size, shape and composition of the shell
within a species, whilst in some instances the patterning of the organic cement which
binds the particles together was a reliable specific character. The present account
uses the experience gained from these previous studies to extend the examination of
shell structure in Difflugia, and to establish specific features for ten of the varieties of
Difflugia oblonga listed by Gauthier-Lievre and Thomas (1958). Thirty nine species
are described, of which some are new records for the British Isles. Some 600
specimens have been examined and over 3000 micrographs representing different
aspects of the shells are retained in the Protozoa Section, Department of Zoology as
part of the study collection.

Materials and methods

Samples have been collected from several localities in England and Wales during the last
four years. The material gathered varied from mosses, water plants including the substrate
associated with the roots, and clumps of algae. Type of habitat ranged from areas of bog,
banks of streams and small ponds in the New Forest, Lake District and North Wales to the
dykes and rivers of Norfolk and Suffolk. Information relating to locality, date and type of
sample is given with the description of each species as several have been found in more than
one habitat.

Specimens of Difflugia were selected by searching through small isolates of material in a
petri dish. Specimens were extracted using a glass micropipette, washed in several transfers
through distilled water, and then individual shells were manipulated with a single-hairbrush
onto a small drop of Araldite on a previously cleaned cover slip. When about twenty
specimens were positioned on each cover slip it was glued with Araldite onto a standard
aluminium stub. In a few instances the very small delicate specimens collapsed before or
during manipulation, this problem was overcome by transferring the washed specimens in a
small drop of water onto cleaned cover slips and allowing it to dry. Prepared stubs were
coated evenly with gold or gold/palladium, using a conventional sputter coating device, and
examined in a Cambridge Stereoscan SI 80 operating at lOkV. The results were recorded on
Ilford HP5 film.

Systematic descriptions

In a previous review (Gauthier-Lievre & Thomas, 1958) of the genus the species were
divided into ten groups, namely; lobed, collared, compressed, urceolate, globose, ovoid-
globose, elongate, acute angled, horned and pyriform, but no particular significance was
attached to these groupings. However, it does show the diversity of shell shape that has been
included in the genus. Similarly in this report the species have been grouped together, the
pyriform and elongate species are described first, followed by those which are pointed or
have aboral protruberances, then the ovoid or spherical and finally the two compressed
species.

Pyriform and elongate species
Difflugia bryophila (Penard, 1 902) Jung, 1 942

Difflugia pyriformis var. bryophila Penard, 1 902

Difflugia oblonga var. bryophila (Penard, 1902) Gauthier-Lievre & Thomas, 1958

DESCRIPTION. The shell is brown, pyriform, with the sides usually tapering evenly to the
aperture (Figs, la & d), although the occasional specimen may be slightly mis-aligned or

DIFFLUGIA IN BRITAIN

Fig. 1 Difflugia bryophila: a, lateral view of shell with large particles obscuring the basic outline
x780; b, apertural view x760; c, portion of shell surface showing the distribution of organic
cement (arrowed) x 5100; d, lateral view of specimen with typical basic outline x440; e, detail
of organic cement x 24 000.

4 C. G. OGDEN

Table 1 Range of measurements (in um) of pyriform specimens.

Number of
specimens

Species

Length
(L)

Breadth
(B)

Diameter of
aperture (d)

B/L

d/L

D. minutissima

7-14

6-10

2-3

D. pulex

28-43

21-30

7-10

0-78 + 0-10

0-26 ±0-04

D. pristis

33-42

21-31

10-13

0-6910-08

0-3110-03

D. glans

67-74

44-50

19-22

D. manicata

60-88

37-54

12-20

0-61+0-04

0-20 + 0-02

D. tenuis

60-87

37-50

17-27

0-57 + 0-06

0-30 + 0-03

D. linearis

96-108

32-38

12-13

0-35 + 0-02

0-12 + 0-01

D. gassowskii

91-120

45-55

16-21

0-50 + 0-05

0-18 + 0-02

D. bryophila

83-141

49-67

16-22

0-55 + 0-07

0-17 + 0-02

D. petricola

96-124

61-84

20-31

0-65 + 0-06

0-23 + 0-03

*(47)

(D. petricola)

(108-151)

(72-99)

(25-36)

(0-62+0-05)

(0-22 + 0-02)

D. paulii

119-130

48-54

19-23

0-40 ±0-01

0-17 + 0-01

D. lanceolata

108-155

56-92

22-32

0-51 ±0-05

0-20 + 0-02

D. parva

131-162

61-80

19-27

0-51+0-Q4

0-17 + 0-02

D. lacustris

140-231

63-94

26-42

0-41+0-04

0-18 + 0-02

D. cylindrus

186-264

91-130

34-49

0-53 + 0-05

0-21+0-02

D. viscidula

165-284

116-215

46-89

0-75 + 0-09

0-3010-04

*measurements quoted from an earlier report (Ogden & Fairman, 1979)

have a large particle obscuring the even-tapering (Fig. la). It is composed mainly of a
mixture of small to medium pieces of quartz and the occasional diatom frustule or siliceous
flagellate cyst. In common with most rough, thick shells, organic cement is seen infrequently
(Fig. Ic), it appears as an open network, with a mesh about 350-450 nm in diameter. The
walls of the mesh are not pronounced but blend with the matrix, the mesh openings are often
covered by inner strands of cement which appear to form a smaller mesh (Fig. le). The
aperture is circular and surrounded by small particles (Fig. Ib), in several of the specimens
examined small flagellate cysts had also been incorporated to give an irregular margin.

MEASUREMENTS (in um). See Tables 1 and 2.

MATERIAL EXAMINED Specimens were collected from samples of Sphagnum moss gathered at
Mately Bog, Lyndhurst, New Forest, Hampshire in March, 1980 and at Mynnd Hiraethog,
Denbigh, Clwyd, North Wales in August, 1980.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Belgium
(Chardez & Gaspar, 1976; Couteaux, 1969), British Isles (Cash el al, 1919), Chile (Jung,
1942), Congo (Chardez, 1964), Czechoslovakia (Rosa, 1957), France (Thomas, 1954),
Gambia (Decloitre, 1947), Germany (Jung, 1936), Roumania (Godeanu et al., 1973), Russia
(Kourov, 1925), Spain (Gracia, \912a), Switzerland (Penard, 1902), Tunisia (Gauthier-
Lievre & Thomas, 1958), West Africa (Decloitre, 1948).

REMARKS. This description is in good agreement with Penard (1902) who stated that the sides
were rather straight and that it was formed of stones which were usually large and angular.

Amongst the sample from Matley Bog were specimens of Pontigulasia which were
indistinguishable in size and shape from those of D. bryophila. Observations of the former
specimens by optical microscopy to determine the presence of an inner diaphragm, the
distinguishing generic character for Pontigulasia, are often difficult. However, detailed
examination by scanning electron microscopy showed that, unless the apertural opening is
blocked, it was easy to identify the inner diaphragm and that additionally there are differ-
ences in their organic cement patterns (a review of the genus Pontigulasia is in preparation).

DIFFLUGIA IN BRITAIN 5

The random selection of these specimens from the sample gave a ratio of 3 : 1 in favour of
D. bryophila.

Difflugia cylindrus (Thomas, 1953) comb. nov.
Difflugia oblonga var. cylindrus Thomas, 1953

DESCRIPTION. The shell is usually opaque, cylindrical, tapering evenly from the aboral
region to the aperture (Fig. 2a). It is composed mainly of medium to large pieces of quartz
with the occasional diatom frustule on the rough surface, but the latter are seldom
incorporated into the thick structure. Small areas of organic cement in the form of a network
are seen infrequently (Fig. 2d). Each mesh of the network is between 300-500 nm in
diameter, has thick walls and is covered by a thin perforated layer of cement, the pores of
which are evenly distributed and are about 30 nm in diameter (Figs. 2e & f)- The
aperture is irregular in both outline and composition, being roughly circular and usually
surrounded by small particles but often incorporating medium particles that produce a
jagged margin (Fig. 2b & c).

MEASUREMENTS (in um). See Tables 1 and 2.

MATERIAL EXAMINED. Specimens were collected from a sample of aquatic plants taken at the
banks of the River Brett, near Hadleigh, Suffolk in August, 1979.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Austria
(Laminger, 19736, 1975, 1976), Belgium (Chardez, 1980; Chardez & Caspar, 1976), Congo
(Chardez, 1964), France (Thomas, 1953, 1954; Thomas & Mabille, 1956), Germany
(Voeltz-Hohn, 1971), Ivory Coast (Gauthier-Lievre & Thomas, 1958), Morocco
(Gauthier-Lievre & Thomas, 1958), Poland (Moraczewski, 1965).

REMARKS. This species was initially described by Thomas (1953) as a new variety of D.
oblonga, he also listed what he considered to be previous descriptions of this variety under
the general descriptions of D. oblonga given by earlier workers. These are not repeated here,
but suggest that this variety may be found throughout Europe. The shape, structure and size
of the shell, together with the distinct patterning of the organic cement matrix as described
above, are considered to be good specific characters sufficient to warrant the raising of this
variety to species rank.

Difflugia gassowskii nom. nov.

Difflugia pyriformis longicollis Gassowsky, 1936

Difflugia longcollis (Gassowsky, 1936) Ogden & Hedley, 1980

DESCRIPTION. The shell is pyriform, with a distinct short neck about one-third of the body
length, and a rounded aboral region (Fig. 3a). It is rough and composed of small to medium
angular pieces of quartz, small areas of organic cement are sometimes seen between particles
(Fig. 3b). The cement is in the form of a network, the mesh of which is about 400-550 nm in
diameter and the walls 125-200 nm thick, each mesh enclosure has a covering with small
perforations about 50 nm in diameter (Fig. 3c). The aperture is circular.

MEASUREMENTS (in um). See Tables 1 and 2.

MATERIAL EXAMINED. Specimens were collected from samples of Sphagnum moss gathered
at Holmsley Lodge, Burley, New Forest, Hampshire in March, 1980 and at Clocaenog
Forest, Denbigh, Clwyd, North Wales in August, 1980.

GEOGRAPHICAL DISTRIBUTION. Belgium (Chardez, 1980; Couteaux, 1969), British Isles
(Ogden & Hedley, 1980), Germany (Voeltz-Hohn, 1971), Netherlands (Hoogenraad &
Groot, 1940a), Nigeria (Gauthier-Lievre & Thomas, 1958), Poland (Moraczewski, 1961,
1965), Roumania (Godeanu et al, 1973), Russia (Gassowsky, 1936), Spain (Gracia, 1972a;
Margalef, 1955).

C. G. OGDEN

Fig. 2 Difflugia cylindrus: a, lateral view x450; b, side view of aperture to illustrate the irregular
margin x770; c, apertural view x410; d, shell surface with areas of organic cement
(arrowed) x4200; e, typical arrangement of organic cement network x 8700; d, detail of organic
cement x 27 000.

DIFFLUGIA IN BRITAIN

Fig. 3 Difflugia gassowskii: a, lateral view x810; b, shell surface with small areas of organic
cement x 7600; c, detail of organic cement network x 24 000.

REMARKS. This species has been redescribed recently (Ogden & Hedley, 1980), but is
included here on two counts, the added detail of the organic cement and the change of name.
The name D. longicollis was used initially by Ehrenberg (1854) to describe specimens which
now are not considered to belong to the genus Difflugia, nevertheless, under the Rules of
Zoological Nomenclature the name is preoccupied. I am grateful to Dr. E. G. Merinfeld,
Dalhousie University, Halifax, Nova Scotia, for drawing my attention to this point.

ENTYMOLOGY. This species is named after Dr G. N. Gassowsky who first described it from
the Kareliens Lakes.

Difflugia glansPenard, 1902

DESCRIPTION. The shell is dark, elongate ovoid, tapering towards the aperture and evenly
rounded aborally (Fig. 4a). It is composed mainly of small to medium pieces of quartz,

C. G. OGDEN

Fig. 4 Dijjlugia glans: a, lateral view x 1400; b, detail of small unidentified cyst x3000; c,
apertural view x 1000; d, portion of shell surface showing the close packing of particles x 3500.

packed closely together with only a minimum amount of organic cement visible (Fig. 4d). A
small cyst, of unknown origin, is seen adhering to the surface of the illustrated specimen
(Fig. 4b), otherwise the outline is usually well denned. The aperture is circular and
surrounded by both small and medium particles (Fig. 4c).

MEASUREMENTS (in um). See Tables 1 and 2.

MATERIAL EXAMINED. Specimens were collected from a sample of water plants taken at the

DIFFLUGIA IN BRITAIN 9

banks of the River Brett, near Hadleigh, Suffolk in August, 1979 and a gathering of
Sphagnum moss from Mynnd Hiraethog, Clwyd, North Wales in August, 1980.

GEOGRAPHICAL DISTRIBUTION. Austria^ (Laminger, 19736), Congo (Chardez, 1964),
Czechoslovakia (Rosa & Lhotsky, 1971; StSpanek, 1952), Germany (Jung, 1936; Schonborn,
1962), Italy (Grandori & Grandori, 1934; Rampi, 1950), Russia (Kourov, 1925).

REMARKS. This species has not been widely reported, which may be because it falls within
the range of three more common species namely, D. penardi, D. manicata and D. rubescens.
It differs from these three species in being a distinct ovoid shape, from D. rubescens in being
dark and not transparent — although Penard's description of a thin, fragile shell for D. glans
does not seem compatible with a dark structure which usually suggests that it is robust and
strong — and from D. penardi and D. manicata in aperture size and shape.

Difftugia lacustris (Penard, 1 899) comb. nov.

Difflugia pyriformis var. lacustris Penard, 1899
Difflugia oblonga var. lacustris Cash & Hopkinson, 1 909

DESCRIPTION. The shell is transparent or hyaline, elongate, cylindrical or slightly pyriform
(Figs. 5a & b). It is composed of small to medium pieces of quartz, diatom frustules and small
siliceous flagellate cysts blended together to form a thin structure intermediate between
smooth and rough. Only small areas of organic cement occur at the junction of the shell
components (Fig. 5d). The cement is in the form of thick-walled rings, between 700-800 nm
in diameter, perforated with either three or four holes, 120-160 nm in diameter, which gives
these units a similar shape to a button (Fig. 5e). The cement may occasionally be seen either
as rings with a slight indentation or as a network of joined rings. When organised as a
network the walls of individual rings may be fused together but the typical button-like
form are usually seen at the edges. The aperture is usually circular and surrounded by small
particles so that the margin is smooth (Fig. 5c).

MEASUREMENTS (in um). See Tables 1 and 2.

MATERIAL EXAMINED. Specimens were collected from three samples in the same locality,
aquatic plants at the edge of a pond in Burley, and two gatherings of Sphagnum from
opposite banks of a small stream at Holmsley Lodge, Burley, New Forest, Hampshire in
March, 1980.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Argentina
(Dioni, 1970; Lena & Zaidenwerg, 1975), Austria (Laminger, 19736 1974, 1975), Belgium
(Chardez, 1980; Chardez & Gaspar, 1976; Oye, 1953), British Isles (Cash & Hopkinson,
1909), Congo (Chardez, 1964; Gauthier-Lievre & Thomas, 1958), Czechoslovakia
(Stepanek, 1967), France (Thomas, 1954; Thomas & Mabille, 1956), Germany (Jung, 1936;
Schonborn, 1962a & b), Guatemala (Laminger, 1973a), Italy (Rampi, 1950), Ivory Coast
(Gauthier-Lievre & Thomas, 1958), Mexico (Laminger, 1973a), Morocco (Gauthier-Lievre
& Thomas, 1958), Poland (Moraczewski, 1961, 1965), Roumania (Godeanu et al., 1973),
Russia (Kourov, 1925), Switzerland (Penard, 1902), United States of America (Laminger
etal., 1979;Wailes, 1912).

REMARKS. The specimens described here agree well with the original description (Penard,
1899)— shell long, cylindrical, larger in the rear, rarely with a small constriction of the
neck— and those given later by Penard (1902) and Cash & Hopkinson (1909). Nevertheless,
it would appear that these earlier descriptions were based on groups of similar specimens,
hence Penard's reference to a constriction of the neck and the diverse illustrations provided
by Cash & Hopkinson. As a result of the latter diagrams, two specimens were tentatively
identified as D. lacustris in a previous publication (Ogden, 1980). Additional specimens to

C. G. OGDEN

Fig. 5 Difflugia lacustris: a, lateral view x 450; b, alternative view of same specimen (a.) to
illustrate the uniform shape x280; c, apertural view x500; d, shell surface showing the
distribution of organic cement x 5800; e, detail of organic cement network x 24 000.

DIFFLUGIA IN BRITAIN 1 1

the two mentioned above have been examined and are clearly seen to differ from D. lacustris,
they are now referred to D. linearis (see below).

The present account shows that D. lacustris has a well denned shape and a distinctive
patterning of organic cement which are considered sufficient to designate this a distinct
species.

Difflugia lanceolata Penard, 1 890

DESCRIPTION. The shell is yellow or hyaline, lanceolate, tapering from the widest diameter
situated about two- thirds of the body-length from the aperture, to give a clean outline that is
rounded aborally and evenly angled towards the aperture (Fig. 6a). It is composed of small
to medium flattish pieces of quartz and some flat diatom frustules so arranged that the shell is
thin and smooth, the surface frequently appearing as though it had been polished, a feature
that often permits easy identification. An angular piece of quartz may occasionally protrude
from the surface but these are uncommon and limited to one or two in any one shell. As the
shell components are usually arranged so that they are in close contact with each other there
are no large areas of organic cement, nevertheless, a network of small rings of organic cement
may be seen between these particles (Figs. 6d, e, f)- The rings are 240-300 nm in diameter
and have a distinct wall about 1 50-200 nm in thickness with a smooth membrane over the
mesh. When several rings fuse to form a sheet the thick wall is still usuallv apparent. The
aperture is circular and well defined because the rim has a thin covering of organic cement
(Figs. 6b & c).

Variation appears to be limited to cigar-shaped specimens which have almost parallel
sides, one such specimen is illustrated by Ogden & Hedley (1980).

MEASUREMENTS (in um). See Tables 1 and 2.

MATERIAL EXAMINED The majority of specimens came from a sample of Sphagnum moss
collected close to a small stream at Holmsley Lodge, Burley, New Forest, Hampshire, a few
came from a similar sample on the opposite bank where they were equally abundant, both
samples were taken in March, 1 980.

GEOGRAPHICAL DISTRIBUTION. Argentina (Vucetich, \913a, /?), Austria (Laminger, 1972c),
Belgium (Chardez, 1961; Oye, 1953), Brazil (Green, 1975), British Isles (Cash & Hopkinson,
1909; Ogden & Hedley, 1980), Canada (Decloitre, 1965), China (Decloitre, 1965), Congo
(Chardez, 1964), Czechoslovakia (Opravilova, 1974), France (Thomas, 1954; Thomas &
Mabille, 1956), Germany (Schonborn, 1975), Hungary (Gal, 1969), Java (Bartos, 1963a),
Morocco (Gauthier-Lievre & Thomas, 1958), Poland (Golemansky, 1970; Moraczewski,
1961, 1965), Roumania (Godeanu et al, 1973), Sudan (Gauthier-Lievre & Thomas, 1958),
Switzerland (Penard, 1902), Venezuela (Grospietsch, 1975), West Africa (Decloitre, 1965),
United States of America (Decloitre, 1965).

REMARKS. The organic rim surrounding the aperture is shared with one other pyriform
species of Difflugia, namely D. rubescens where the cement is in the form of tooth-like
projections (see PI. 66 in Ogden & Hedley, 1980). The only other species of which we are
aware that has an organic rim is D. oviformis, but this was transferred to a new genus Netzelia
by Ogden, 1979. D. lanceolata is characterized by its uniform size and outline.

Difflugia linearis (Penard, 1 890) Gauthier-Lievre & Thomas, 1958

Difflugia oblonga var. linearis Penard, 1890
Difflugia lacustris in Ogden, 1980

DESCRIPTION. The shell is transparent, flask-shaped or elongate pyriform, having a long thin
neck with parallel sides and a slightly swollen, rounded aboral region (Fig. 7 a). The surface is
sometimes slightly uneven because of projecting particles, but generally it has a regular

C. G. OGDEN

Fig. 6 Difflugia lanceolata: a, lateral view x 930; b, apertural view x 760; c, side view of aperture
to illustrate the thin covering of organic cement around the rim x 1500; d, shell surface with
small isolates of organic cement x4400; c, small rings of organic cement between particles
x 7600; f, detail of organic cement x 24 000.

DIFFLUGIA IN BRITAIN

Fig. 7 Difflugia linearis: a, lateral view x950; b, apertural view x!200; c, portion of shell
surface showing areas of organic cement (arrowed) x 14 000; d, detail of organic cement
X 24 000.

outline. It is composed of a mixture of flattened pieces of quartz, small whole, flat diatom
frustules, fragments of flattish frustules, small siliceous shell plates and round flagellate cysts.
Small areas of organic cement, in the form of a network with an open mesh, are occasionally
seen (Fig. 7c), The open mesh has a diameter of about 300 nm and walls 100 nm thick (Fig.
7d). In appearance, the openings of the mesh suggest that it may have been covered at some
time and has subsequently been broken, but only the examination of further specimens will
establish its normal condition. The aperture is circular and usually surrounded by small
particles (Fig. 7b).

MEASUREMENTS (in um). See Tables 1 and 2.

MATERIAL EXAMINED. Specimens were collected from Sphagnum moss gathered at Holmsley

C. G. OGDEN

Lodge, Burley, New Forest, Hampshire on two occasions, May, 1978 and March, 1980, and
at Myndd Hiraethog, Denbigh, Clwyd, North Wales in August, 1980.

GEOGRAPHICAL DISTRIBUTION. Austria (Laminger, 19736, 1975), Belgium (Chardez, 19616),
British Isles (Ogden, 1980), Bulgaria (Golemansky, 1967), Congo (Chardez, 1964), France
(Thomas, 1954), Germany (Penard, 1890), Ivory Coast (Gauthier-Lievre & Thomas, 1958),
Nepal (Laminger, 19726), Roumania (Godeanu et at, 1973).

REMARKS. The initial description of this species (Penard, 1890) was brief, and relies mainly
on the diagrams. The scarcity of subsequent reports may be due to this inadequate
description or the difficulty in finding this species, which by being thin, long and transparent

Fig. 8 Difflugia manicata: a, lateral view x 1300; b, apertural view x 1 100; c, and d, detail of
organic cement with the ill-defined inner structure (arrowed) x 30 000.

DIFFLUGIA IN BRITAIN

Fig. 9 Difflugia minutissima: a, lateral view to show the arrangement of flattish particles x 6700;
b, detail of aperture x 10 000; c, latero-apertural view x4900.

makes it unusually elusive. Two specimens described earlier (Ogden, 1980) and tentatively
identified as Difflugia lacustris, because of their similarity to the description given by Cash &
Hopkinson (1909) and especially to one figure (PI. XIX Fig. 1), are now redescribed as D.
linearis. Additional specimens, plus the benefit of being able to compare these with
specimens of D. lacustris (see p. 9), allows the former identification to be rectified and show
that D. linearis is a distinct species.

Difflugia linearis can be differentiated from other pyriform species by its distinctive
flask-like shape, thin, transparent shell and small aperture.

16 C. G. OGDEN

Difflugia manicata Penard, 1 902

DESCRIPTION. The shell is yellow or brown, pyriform, tapering evenly and gradually from a
rounded aboral extremity towards the aperture (Fig. 8a). The surface is rough and
composed mainly of small to medium pieces of quartz, although the occasional specimen
may have large particles added. Small areas of organic cement are seen infrequently, due to
the close packing of the shell material, but when present they appear either as strands or as
pores in a matrix (Fig. 8c). These pores are about 300 nm in diameter and have an ill-defined
inner structure which appears to have smaller pores about 1 30 nm in diameter (Figs. 8c & d).
The aperture is circular and surrounded by a distinct pattern of small particles
(Fig. 8b).

MEASUREMENTS (in um). See Tables 1 and 2.

MATERIAL EXAMINED. Specimens were collected from samples taken at three sites,
Sphagnum moss gatherings at Holmsley Lodge, Burley, New Forest, Hampshire in March,
1980 and Mynnd Hiraethog, Clwyd, North Wales in August, 1980, and from aquatic plants
taken at the banks of the River Brett, near Hadleigh, Suffolk in August, 1979.

GEOGRAPHICAL DISTRIBUTION. Austria (Laminger, 1971, 1972c), Belgium (Chardez, 196 \b\
British Isles (Cash el al, 1919; Ogden & Medley, 1980), Congo (Stepanek, 1963), Italy
(Grandori & Grandori, 1934), Poland (Moraczewski, 1965; Pateff, 1926, 1927), Switzerland
(Penard, 1902).

REMARKS. Although this species was thought to be uncommon by Cash, Wailes &
Hopkinson (1919), it is suggested that this has been one of the overlooked species and that it
will probably be found as one of the most commonly distributed. The wide range of habitat
already reported, lake, river and Sphagnum moss would appear to support this opinion.

Difflugia minutissima Penard, 1904
Sexangularia minutissima (Penard, 1 904) Deflandre, 1931

DESCRIPTION. The shell is transparent, elongate or ovoid, rounded aborally and tapering
slightly towards the aperture (Figs. 9a & c). It is composed of thin flattish pieces of quartz,
and the occasional diatom frustule, which are arranged so that they overlap, but the result is
still a fragile structure. Only small strands of organic cement have been seen at some
junctions. The aperature is basically circular, any variation is usually due to the irregular
arrangement of particles around the opening (Fig. 9b).

MEASUREMENTS (in urn). See Tables 1 and 2.

MATERIALS EXAMINED. Specimens were collected from a sample of Sphagnum moss gathered
at Mynnd Hiraethog, Clwyd, North Wales in August 1980.

GEOGRAPHICAL DISTRIBUTION Switzerland (Penard, 1904)

REMARKS. This species appears to be known only from the initial description (Penard, 1 904),
although Deflandre (1931) using Penard's description suggested that it should be transferred
to the genus Sexangularia Awerintzew, 1906. The main features of this latter genus are
'chitinous shell, with or without the addition of extraneous particles; polygonal in transverse
section, most often hexagonal'. At present it is considered that these features are insufficient
to differentiate this genus from Difflugia, and therefore refer the included species to
Difflugia-D. minutissima Penard, 1904; D. parvula (Awerintzew, 1906) and D. polydera
Deflandre, 1931.

The specimens described here were found adhering to extraneous particles when prepared
by air-drying and because of this it is not possible to examine them in transverse section,

DIFFLUGI A IN BRITAIN 17

nevertheless, they do not appear to be polygonal. The value of this feature in relation to a
fragile shell is questionable, especially as Penard's observations would have been carried out
on specimens under a cover slip, which would allow a degree of compression. The specimens
share similar dimensions to those given by Penard for D. minutissima and are so designated.

Difflugia parva (Thomas, 1954) comb. nov.
Dijjlugia oblonga var. parva Thomas, 1954

DESCRIPTION. The shell is pyriform, tapering evenly from the swollen and rounded aboral
third, to the aperture for the remaining two-thirds (Fig. lOa). It is composed mainly of a
mixture of small to medium pieces of quartz, often with the addition of two or three large
pieces. Organic cement is seen between particles usually as a series of single units (Fig. 1 Oc),
which may overlap but are seldom fused to form a network. Each unit is a ring about
650-750 nm in external diameter, 300-380 nm internal diameter, with walls about 150 nm
thick. A small mesh covers the inner portion of each ring (Fig. lOd). The aperture is circular
and surrounded mainly by small particles (Fig. lOb).

MEASUREMENTS (in urn). See Tables 1 and 2.

MATERIAL EXAMINED. Specimens were collected from Sphagnum moss gathered at Matley
Bog, Lyndhurst, New Forest, Hampshire in March, 1980; Mynnd Hiraethog, Denbigh,
Clwyd, North Wales in August, 1980 and aquatic plants from a pond at Hurley, New Forest,
Hampshire in March, 1980.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Argentina (Lena
& Zaidenwerg, 1975), Austria (Laminger, 19736), Belgium (Chardez, 1980; Chardez &
Caspar, 1976; Couteaux, 1969), Bulgaria (Golemansky, 1967), France (Thomas, 1954;
Thomas & Mabille, 1956), Germany (Schonborn, 1965; Voeltz-Hohn, 1971), Ivory Coast
(Gauthier-Lievre & Thomas, 1958), Poland (Golemansky, 1970; Moraczewski, 1965),
Venezuela (Grospietsch, 1975).

REMARKS. There have been several reports of D. oblonga var. parva since Thomas (1954)
described his new variety, although size was the only diagnostic feature used and illustrated
(PI. Ill, Fig. 1) by him to differentiate this variety from D. oblonga. The figure given also
shows the difference in shell composition, described below as a specific feature.

This variety is considered as a distinct species from Z>. oblonga because of its clean outline,
relatively smooth surface and detailed cement pattern.

Difflugia paulii nom. nov.
Difflugia oblonga var. elongata Oye, 1953

DESCRIPTION. The shell is transparent, slim and elongate, tapering evenly from just anterior
of the mid-body region towards the aperture, the even-tapering is more apparent in Fig. lib
whereas the upper side of Fig. 1 la has a misleading hump, the posterior region is slightly
swollen, curving sharply and smoothly at the extremity (Fig. 1 la). It is composed of flattish
pieces of quartz to give a smooth appearance, with small areas of organic cement often
apparent as part of the matrix (Fig. lie). The cement is in the form of small perforated cones
about 600 nm in diameter, the perforations being about 100-1 50 nm in diameter (Fig. 1 Id).
The aperture is circular and surrounded by small pieces of quartz (Fig. 1 Ib).

MEASUREMENTS (in nm). See Tables 1 and 2.

MATERIAL EXAMINED. Specimens were collected from a sample of Sphagnum moss gathered
at Mynnd Hiraethog, Denbigh, Clwyd, North Wales in August, 1980.

C. G. OGDEN

Fig. 10 Difflugia parva: a, lateral view x 710; b, apertural view x 790; c, shell surface showing
areas of organic cement x 9800; d, detail of organic cement x 30 000.

DIFFLUGIA IN BRITAIN

J V * ,. f '^ t
RS- .y .-.!'*^i-J*'..3L'^L » .-,

Fig. 11 Difflugia paulii: a, lateral view x800; b, apertural view x790; c, portion of shell
surface x 4600; d, detail of organic cement x 1 5 000.

GEOGRAPHICAL DISTRIBUTION. Austria (Laminger, 19736), Belgium (Oye, 1953), Congo
(Gauthier-Lievre & Thomas, 1958), Spain (Gracia, 19720).

REMARKS. This species has been described on two occasions, from Belgium by Oye (1953)
and from Africa by Gauthier-Lievre & Thomas (1958). Oye (1953) stated that these
specimens were slender in comparison with D. lacustris, and considered that this feature and
the limited grains of quartz in the shell was sufficient to warrant a new variety. Gauthier-
Lievre and Thomas (1958) agreed with this earlier description and designation.

Of the more elongated pyriform species, D. paulii in body length appears to occupy a
position mid-way between D. linearis and D. lacustris, the present work shows that it is
distinct from these two species in outline, elemental composition and patterning of the

20 C. G. OGDEN

organic cement, in addition, it can be differentiated from D. linearis by the size of the
aperture (Table 1).

ETYMOLOGY. This species is named after Dr Paul van Oye whose original description was
based on specimens from a pond in Belgium.

DifflugiapetricolaCash, 1909

This species has been redescribed recently by Ogden & Fairman (1979). It is reported here
only to demonstrate the regularity of dimensions between specimens from different
localities, see Tables 1 and 2, because these are often used as taxonomic features.

MATERIAL EXAMINED. Specimens were collected from Sphagnum moss gathered at two sites,
Holmsley Lodge, Burley, New Forest, Hampshire in March, 1980 and Mynnd Hiraethog,
Denbigh, Clwyd, North Wales in August, 1980.

Dijflugia pristis Penard, 1902

DESCRIPTION. The shell is brown or opaque, ovoid, tapering from the mid-body position
towards the aperture and gracefully curved aborally (Fig. 12a). It is thin, smooth and
composed of flattish pieces of quartz (Fig. 1 2a-c) or infrequently including flat pieces of
diatom frustule. The particles are packed closely together and only small connections of
organic cement are visible (Figs. 12d & e). The aperture is circular with a regular margin
(Fig. 12b).

MEASUREMENTS (in urn). See Tables 1 and 2.

MATERIAL EXAMINED. Specimens were collected from samples of Sphagnum moss gathered
at Holmsley Lodge, Burley, New Forest, Hampshire in May, 1978 and at Myndd Hiraethog,
Denbigh, Clwyd, North Wales in August, 1980.

GEOGRAPHICAL DISTRIBUTION. British Isles (Cash & Hopkinson, 1909), Czechoslovakia
(Stepanek, 1967), Hungary (Varga, 1963), Italy (Grandori & Grandori, 1934), Java (BartoS,
1963a), Poland (Moraczewski, 1965), Roumania (Godeanu et al, 1973), Switzerland
(Penard, 1902).

REMARKS. Cash and Hopkinson (1909) considered their specimens to be in good agreement
with Penard's (1902) description, except for the absence of refractive particles that made the
shell appear opaque or black. This they attributed to the difference in habitat of their
samples, the former being found amongst floating vegetation in clear water and Penard's
from a muddy lake bottom. Some differences in size have been reported since Penard who
gave 45-65 um as the range of length, Cash and Hopkinson gave 60-65 um, whilst more
recently Varga (1963) found specimens measuring 44-48 um in length.

The specimens reported here are smaller than any previously described, although in all
other respects agree with Penard's description. The main features that distinguish D. pristis
from D. pulex are the darker colour and the more regular shape.

A single larger specimen, 56 um long, 31um wide, aperture 10 um in diameter, with the
typical pyriform shape (Fig. 13a & b) was found in the sample from Wales. This is reported
here as being questionably D. pristis (?), being atypical in having a definite neck, the
discovery of more specimens may result in a more accurate identification. This specimen is
similar to those identified by Cash & Hopkinson (1909) as (?) D. pulex which they described
as being 'oval, tapering suddenly to a short neck'.

DIFFLUGIA IN BRITAIN

Fig. 12 Difflugia pristis: a, lateral view x2400; b, apertural view x2400; c, alternative view of
specimen shown in a., to illustrate regular ovoid shape x 1700; d and e, portions of shell surface
with small connections of organic cement (arrowed) x 9300 and x,14J)00.

C. G. OGDEN

Fig. 13 Difflugia pristis (?): a, lateral view to show distinct neck x 860; b, apertural view x 1 600.

Difflugia pulex Penard, 1902
Difflugia minuta minor Godeanu, 1972

DESCRIPTION. The shell is transparent, elongate or ovoid (Figs. 14a & d). It is composed
mainly of a mixture of small thin pieces of flat quartz and pieces of diatom frustule, often
with whole frustules or round flagellate cysts adhering to the surface (Figs. 14a-e). The
arrangement of these particles is such that only small strands of organic cement are visible.
The aperture is usually circular (Fig. 14c) but may vary due to the arrangement of the
surrounding particles (Fig. 14b).

MEASUREMENTS (in urn). See Tables 1 & 2.

MATERIAL EXAMINED Specimens were collected from samples of Sphagnum moss gathered at
Subberthwaite, Broughton in Furaess, Cumbria in June 1979 and at Mynnd Hiraethog,
Denbigh, Clwyd, North Wales in August, 1980.

GEOGRAPHICAL DISTRIBUTION Argentina (Lena & Zaidenwerg, 1975), Australia (Playfair,
1918), Austria (Laminger, J9736), Belgium (Chardez, 19616), British Isles (Cash &
Hopkinson, 1909), Congo (Stdpanek, 1963), Czechoslovakia (Stepanek, 1967), Germany
(Schonborn, \962a & b), Italy (Grandori & Grandori, 1934; Rampi, 1950), Java (BartoS,
1963a), Netherlands (Hoogenraad & Groot, 1940), Roumania (Godeanu et al, 1972), Spain
(Gracia, 19726), United States of America (Laminger et al, 1979), West Africa (Decloitre,
1948).

REMARKS. Penard's original description stated that the shell was-' pyriform, with or without
narrowing of the mouth, chitinoid, slightly yellow, covered with small scales or particles of
amorphous silica, plates, sufficiently transparent to examine the contents' and that
specimens rarely exceeded 30 urn in length. Cash & Hopkinson (1909) described specimens
between 65-70 urn in length that they tentatively identified as D. pulex, but on the basis of
both Penard's and the present description it is now suggested they should be reassigned.

The description of D. minuta minor given by Godeanu (1972), shell colourless circular in
cross section but with an irregular outline because of added quartz particles and a circular
aperture, is so similar to that of D. pulex that it must be considered a synonym. The range of
measurements given are also similar to those quoted here (see Table 1 ).

Although Penard gave 30 urn as the maximum length for this species, in the described
sample two specimens were just in excess of 40 urn and two 30 urn, but in all other respects
were similar to the smaller specimens, and all are considered to represent D. pulex.

DIFFLUGIA IN BRITAIN

Fig. 14 Difflugia pulex: a, lateral view x 1800; b, apertural view of specimen with irregular
apertural opening x 1300; c, apertural view of specimen (a.) with circular aperture x 1500; d,
lateral view of specimen mainly made of flattish particles x 1600; e, shell surface showing
mixture of flat components x 5 100.

24 C. G. OGDEN

Difflugia tenuis (Penard, 1 890) comb. nov.

Difflugia pyriformis var. tenuis Penard, 1890
Difflugia oblonga var. tenuis Wailes & Penard, 1911

DESCRIPTION. The shell is usually transparent, cylindrical or slightly pyriform, composed of
a mixture of mainly small to medium pieces of angular quartz, but with an occasional large
particle added (Figs. 15a & b). Sometimes additional particles give a pointed outline to the
aboral region, instead of the usual rounded contours. Organic cement is seen frequently as
single units between shell components (Fig. 15d), and occasionally in small patches where
these units are in a network with a mesh diameter of 350-400 nm and walls 180-220 nm
thick (Fig. 1 5e). The mesh surface is characterised by a thin, usually central, inner ring about
1 50-200 nm in diameter (Fig. 15e). The aperture is roughly circular, often having an
irregular outline because of the mixture of particles surrounding it (Fig. 1 5b).

One specimen with projections similar to the rigid 'filament' structures described by
Penard (1890), occurred in the present sample (Fig. 15c). These projections usually arise
from a common base, on the surface of the quartz particles, and vary in size and number (Fig.
16a). The projections are about 250 nm in diameter and may be up to 7 um in length, as
many as fifteen have been seen sharing a common base (Fig. 1 6b). On the present evidence
they seem to be rosettes of bacterial rods rather than the parasitic organisms suggested by
Penard (1890).

MEASUREMENTS (in urn). See Tables 1 and 2.

MATERIAL EXAMINED. Specimens were collected from Sphagnum moss gathered at Holmsley
Lodge, Burley, New Forest, Hampshire in March, 1980 and Mynnd Hiraethog, Denbigh,
Clwyd, North Wales in August, 1980.

GEOGRAPHICAL DISTRIBUTION Argentina (Dioni, 1970), British Isles (Cash et al, 1919),
Germany (Penard, 1 890), Poland (Golemansky, 1970), Venezuela (Grospietsch, 1975).

REMARKS. Although the specimens described here are a little longer than those reported by
Penard (1890) they are otherwise in good agreement with his description. This species has
been identified previously on only a few occasions, but this may be due to its being mistaken
for the more common species in this size range, for example D. penardi and D. rubescens.
There remains the question of specific biological requirements, food, temperature, pH etc.,
which may be the reason why although the site at Holmsley has been sampled regularly for
five or six years, March 1980 was the first time that this species has been seen there and then
it appeared in significant numbers. This species is distinguished by its shape, size of aperture
and the pattern of the organic cement.

Difflugia viscidula Penard, 1 902

DESCRIPTION. This species has been redescribed recently by Ogden & Hedley (1980) but is
reported again with some additional information.

The shell is opaque, pyriform or elongate ovoid, aborally it is usually rounded (Fig. 17a)
but may occasionally be pointed. It is composed of a mixture of different sizes of angular
quartz, with organic cement seen infrequently as part of the surface matrix. The cement
appears as single units squashed together so that they are adjacent or overlap (Fig. 1 7c). The
aperture is circular and usually surrounded by small particles which give it a characteristic
well-defined outline (Fig. 17b). The illustrated aperture has a cyst plug, which although
broken at one edge has in general a smooth surface, suggesting that it is mainly organic but
reinforced by particles of quartz. About 10% of the examined specimens had an apertural
cyst plug.

MEASUREMENTS (in um). See Tables 1 and 2.

DIFFLUGIA IN BRITAIN

Fig. 15 Difflugia tennis: a, lateral view x 1000, b, apertural view x780; c, specimen with
'filament-like' structures projecting from the surface x 780; d, shell surface showing small areas
of organic cement x 8 100; e, detail of organic cement network x 24 000.

C. G. OGDEN

Fig. 16 Difflugia tennis: a, portion of shell surface to show distribution of 'filament-like'
structures x2500; b, rosette of 'filaments', tentatively identified as bacterial rods x 7000.

MATERIAL EXAMINED Specimens were collected from a sample of Sphagnum moss gathered
at Holmsley Lodge, Burley, New Forest, Hampshire in March, 1980.

GEOGRAPHICAL DISTRIBUTION. Argentina (Boltovskoy & Lena, 1974), Austria (Laminger,
1971), British Isles (Ogden & Hedley, 1980), Germany (Schonborn, \962a, 1965, 1975), Java
(BartoS, 1963a),Roumania(Godeanu^0/., 1973), Switzerland (Penard, 1902).

REMARKS. The present material extends the measurements we gave previously (Ogden &
Hedley, 1980) to encompass those given by Penard (1902). There remains the problem of
priority of names for these specimens because Penard (1902) described two distinct species,
namely D. lemani Blanc, 1892 and D. viscidula sp. nov., which he differentiated mainly on
size; the former being 50-85 um long (three individuals were 100-200 um) and the latter
180-260 um long. When he later found (Penard, 1905) that he had used incorrect measure-
ments for D. lemani he suggested that D. viscidula should be regarded as a synonym.
However, this proposal left his description of specimens under the name D. leman /-Penard,
1902 p. 249, without a proper designated name. They were divided into two series, the first
slim, between 75-85 um long and the second wider, but smaller about 50 urn long. It would
appear that no subsequent report has rectified this situation, and it would seem that now is
too late to change this because of the proliferation of species that have since been described
and fall within the size range of the earlier description. Furthermore, it appears that Blanc's
(1892) original description of D. lemanii might contravene Article 8 of the International
Code of Zoological Nomenclature, because when first issued it would seem that it was not
available by purchase or free distribution. There are no records of this publication in either
this Museum's Libraries nor in the British Library, although I have recently obtained a
photocopy from the Universitaire Lausanne. In Blanc's initial description of D. lemanii the
shell dimensions varied as follows: body length between 180-310 um, breadth 130-150 um.
and the aperture diameter was given as 1 lOum, it had a cylindrical body with almost parallel
sides and the composition was such that it was friable and delicate. These measurements are
in good agreement with Penard's 180-260 um body length for D. viscidula, and those given
here in Table 1 except for the diameter of the aperture, this latter feature is given as being
equal to about half the breadth of the shell by Penard (1905). The diameter of the aperture
and the pyriform rather than cylindrical shape of the body are considered sufficient to
differentiate the present specimens and those of Penard (1902, 1905) from D. lemanii Blanc,
1892. This therefore leaves Penard's designated name of D. viscidula as valid and the
specimens described here are so named.

DIFFLUGIA IN BRITAIN

Fig. 17 Difflugia viscidula: a, lateral view x410; b, detail of aperture which is blocked by a cyst
plug x 1000; c, detail of organic cement x 13 000.

Pointed species or those with protruberances

Difflugia amphoralis Cash & Hopkinson, 1 909

DESCRIPTION. The shell is transparent, squat pyriform with the aboral extremity tapering
evenly to a point (Figs. 19a & b). It is composed mainly of medium pieces of quartz with
small pieces mixed and so arranged to produce an intermediate smooth surface. Organic
cement is seen in small patches between particles (Fig. 19d) and appears as rings fused to

linearis I \gassowskii/ \ bryophila I V petricola

Fig. 18 Diagrams of pyriform and elongate species to illustrate the basic, outline based on

measurements given in Table 2.

Table 2 Average dimensions of pyriform specimens listed in
Table 1 and illustrated in Fig. 18.

Species

Length

Breadth

Diameter of
aperture

D. minutissima

D. pulex

D. pristis

D. glans

D. manicata

D. tennis

D. linearis

100

D. gassowskii

102

D. bryophila

108

D. petricola

111

D. paulii

126

D. lanceolata

128

D. parva

149

D. lacustris

183

D. cylindrus

211

112

D. viscidula

217

161

DIFFLUGIA IN BRITAIN

Fig. 19 Difflugia amphoralis: a, lateral view x850; b, lateral view to show even aboral
tapering x 500; c, apertural view x 760; d, shell surface showing areas of organic cement
x 4500; e, detail of organic cement network x 24 000.

30 C. G. OGDEN

form a network, each mesh of which is about 380-450 nm internal diameter and the raised
walls are 130 nm thick, a smooth membrane covers each enclosure (Fig. 19c). The circular
aperture is surrounded by a small rim of mainly small particles to give a poorly defined
border (Figs. 19a,b&c).

MEASUREMENTS (in urn). A single specimen: body length 109, breadth 62, diameter of
aperture 28.

MATERIAL EXAMINED. The specimen was found in Sphagnum moss gathered at Holmsley
Lodge, Burley, New Forest, Hampshire in March, 1980.

GEOGRAPHICAL DISTRIBUTION. British Isles (Cash & Hopkinson, 1909), Tashkent
(Pashintowa, 1929).

REMARKS. The structure of the shell in the present specimen differs from the original (Cash &
Hopkinson, 1909) by being composed mainly of quartz particles, rather than 'amorphous
(?siliceous) scales'. However, it should be noted that the specimens described by Leidy (1879)
and quoted as synonyms of this species by Cash & Hopkinson (1909) are also composed
mainly of 'quartz sand'.

Difflugia bicruris Gauthier-Lievre & Thomas, 1958

DESCRIPTION. The shell is elongate ovoid, the sides being almost parallel with a slight
tapering towards the aperture and the aboral extremity, the latter is rounded and has two
small, equally spaced, protruberances or horns (Figs. 20a & c). It is composed of medium to
large pieces of angular quartz, with some small particles being used in shaping the horns (Fig.
20d). The surface is rough but patches of organic cement are seen to form part of the shell
matrix (Fig. 20e). Organic cement is arranged in the form of a regular network whose mesh
has a diameter of about 300-350 nm and the distance between each enclosure is about
300 nm (Fig. 20f). The aperture is circular and surrounded by an even arrangement of small
particles (Fig. 20b).

MEASUREMENTS (in um). Two specimens: body length 202-207, breadth 95-1 1 5, diameter of
aperture 4 1-5 8.

MATERIAL EXAMINED. Specimens were collected from aquatic plants taken at the banks of the
River Brett, near Hadleigh, Suffolk, in August, 1979.

GEOGRAPHICAL DISTRIBUTION Ivory Coast (Gauthier-Lievre & Thomas, 1958), Poland
(Golemansky, 1970).

REMARKS. Slight differences exist between the present specimens and those described by
Gauthier-Lievre & Thomas (1958). They have slightly larger general body measurements,
although the proportions are directly comparable, and the horns are reduced in length,
20 urn here compared with 30-33 um in the African specimens. Nevertheless, the
descriptions are in good agreement showing that D. bicruris is distinctly ovoid with two
aboral spines or horns.

Difflugia distenda nom. nov.
Difflugia acuminata var. inflata Penard, 1899

DESCRIPTION. The shell is transparent, pyriform with the aboral extremity acutely curved
towards a small central tubular horn (Fig. 2 la), although the extent of the angle may be less
acute in a few specimens. It has an intermediate smooth surface and thickness, being
composed mainly of small to medium pieces of quartz, with occasional diatom frustules
added. Areas of organic cement are sometimes seen in the shell matrix as a network (Fig.
21c), with a mesh 350-400 nm in diameter and walls 150-200 nm thick (Fig. 21d). The

DIFFLUGIA IN BRITAIN

Fig. 20 Difflugia bicruris: a, lateral view illustrating the two aboral horns x 420; b, apertural
view x400; c, alternative lateral view with aboral horns not easily seen x430; d, detail of aboral
horn x2500; e, portion of shell surface showing distribution of organic cement x2700; f, detail
of organic cement network x 25 000.

C. G. OGDEN

Fig. 21 Difflugia distenda: a, lateral view to show small aboral horn x430; b, apertural
view x350; c, shell surface showing large areas of organic cement x2400; d, detail of organic
cement network x 1 1 000.

aperture is circular and usually surrounded by an even arrangement of small particles (Fig.
21b).

MEASUREMENTS (in urn). Based on ten specimens: body length 217-270, breadth 109-135,
diameter of aperture, 58-64; B/L 0-53 ±0-04, d/L 0-26 ±0-02.

MATERIAL EXAMINED. Specimens were collected from a sample of Sphagnum moss gathered
at Holmsley Lodge, Burley, New Forest, Hampshire in March, 1980.

DIFFLUGIA IN BRITAIN 33

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Austria
(Laminger, 1971, 19736), Belgium (Chardez, 196 la), British Isles (Cash & Hopkinson,
1909), Congo (Chardez, 1964; Gauthier-Lievre & Thomas, 1958), France (Deflandre, 19626;
Thomas & Mabille, 1956), Gabon (Gauthier-Lievre & Thomas, 1958), Ivory Coast
(Gauthier-Lievre & Thomas, 1958), Mexico (Laminger, 19736), Morocco (Gauthier-Lievre
& Thomas, 1958), Poland (Golemansky, 1970; Moraczewski, 1965), Switzerland (Penard,
1902), Tashkent (Pashintowa, 1967).

REMARKS. The variations of D. acuminata, and its twelve varieties has recently been
illustrated by Chardez (1961). More recently it has been shown (Ogden, 1979) that D.
acuminata Ehrenberg, 1838 has a distinctive elongate shape and an apparently unique
organic cement pattern. Specimens described as var. inflata differ from this species in shape,
size and organic cement pattern, the former is clearly demonstrated when the measurements
are expressed as ratios, the comparable ratios for D. acuminata are B/L 0-36 ±0-03 and d/L
0-1 5 ±0-03 (Ogden, 1979).

The specimens described here agree well with Penard's (1899, 1902) original descriptions,
and the differences from D. acuminata are considered sufficient to warrant specific
designation. Our normal practise is to raise the variety name to specific rank, but on this
occasion it is impracticable as the terminology inflata has been used several times in
connection with specimens of Difflugia, for example D. curvicaulis var. inflata Decloitre,
1951.

ETYMOLOGY The specific name has been selected to reflect the inflated condition of the shell
(L. distenda = swell out).

Difflugia labiosa Wailes, 1919
Difflugia amphora Leidy 1879 of Penard, 1901; 1902 & 1905

DESCRIPTION. The shell is opaque or dark brown, ovid or elongate ovoid, tapering from the
mid-body region sharply to the rounded or pointed aboral extremity and more gradually
towards the aperture (Fig. 22a). It is relatively thick and composed of quartz pieces so
arranged that small particles fill the interstices between the larger pieces which form a
mainly smooth surface (Fig. 22d). Organic cement is seen infrequently but is in the form of a
network, each mesh being about 250-350 nm in diameter and is usually covered by a smooth
membrane (Fig. 22e). The aperture is roughly circular but is sinuous with as many as six or
seven undulations or lobes (Fig. 22b). It is slightly recessed into the main body, as though it
was surrounded by a groove, the margin or lips, are thin and bordered by tiny particles of
quartz. (Fig. 22b & c).

MEASUREMENTS (in um). Based on five specimens: body length 150-21 1, breadth 112-158,
diameter of aperture 50-63.

MATERIAL EXAMINED. Specimens were collected from aquatic plants taken at the banks of the
River Brett, near Hadleigh, Suffolk in August, 1979.

GEOGRAPHICAL DISTRIBUTION. Austria (Laminger, 1971, 1975), Belgium (Chardez, 1980),
British Isles (Cash et al, 1919; Ogden & Hedley, 1980), Czechoslovakia (Ertl, 1965;
Stepanek, 1952, 1967), France (Thomas, 1954; Thomas & Mabille, 1956), Germany
(Grospietsch, 1958; Schonborn, 19620, & 6), Netherlands (Hoogenraad & Groot, 1940),
Poland (Moraczewski, 1961, 1965), Russia (Kourov, 1925), South Africa (Oye, 1931),
Switzerland (Penard, 1902), Venezuela (Deflandre 1926a; Grospietsch, 1975).

REMARKS. There has been some confusion over the correct name for this species, most recent
authors using D. amphora Leidy, 1879, basing their identifications on the description given
by Penard (1902). However, this name is preoccupied as it was used by Ehrenberg (1854,
1872) to describe a specimen which is no longer considered to be a species of Difflugia. It

C. G. OGDEN

•? •

fc:4-^"""X-
.

Fig. 22 Difflugia labiosa: a, latero-apertural view to show arrangement of particles x 580; b,
apertural view illustrating the undulations or lobes x470; c, lateral view of aperture to show
slight groove and small particles on margin x990; d, portion of shell surface showing the close
packing of particles x 1 300; e, detail of organic cement x 24 000.

DIFFLUGIA IN BRITAIN 35

follows that the later reports by Leidy (1874, 1879) default for the same reason. The latter
report being more confusing by quoting D. amphora as a synonym of D. urceolata, whilst
giving a figure of D. ureceolata var. amphora. Wailes (in Cash et ai, 1919) noted these earlier
reports and proposed the new name D. labiosa, giving Penard's (1901 , 1902, 1905) reports as
synonyms. Earlier, Cash & Hopkinson (1909) had suggested that part of Leidy 's (1879)
description of/), urceolata var. amphora was a synonym of their new species D. amphoralis.
The specimens described here are in good agreement with Penard (1902) who gave a range of
body lengths 150-270 urn, but usually about 200-210 urn, and Wailes who suggested that it
was a rare species from his single 265 um long specimen.

This species is distinct in its ovoid-conical shape plus the lobed aperture with distinct
margin and recessed base.

Difftugia mamillaris Penard, 1 893

DESCRIPTION. The shell is colourless or hyaline, ovoid elongate, swollen or arched in the
mid-region but tapering at both extremities, to give a rounded protruberance aborally and
gradually near the aperture to give a slightly pronounced neck (Fig. 23a). Irregularities in
general shape are not uncommon, for example one specimen although tapered did not have
an aboral protruberance, whilst another (Fig. 23c) tapered markedly from the mid-body
region. It is composed mainly of small to medium pieces of quartz so arranged that the larger
particles tend to be in the mid-body region whilst the extremities have the smaller particles,
overall it usually produces an intermediate thickness of a single layer and a relatively smooth
outline. Organic cement occurs in small patches as a network, which has walls about
80-1 30 um thick between each mesh but sometimes 230 um thick at junctions. Each mesh is
about 250nm in diameter and is covered by a smooth membrane which is distinct in having
three or four small white spots on the surface of each enclosure (Figs. 23d & e). The aperture
is circular, composed of small particles, and roughly finished so that the margin appears
uneven or serrated (Fig. 23b).

MEASUREMENTS (in um). Based on twenty-three specimens: body length 93-111, breadth
54-72, diameter of aperture 23-3 1 .

MATERIAL EXAMINED. Specimens were collected from a sample of aquatic plants taken at the
banks of the River Brett, near Hadleigh, Suffolk in August, 1979.

GEOGRAPHICAL DISTRIBUTION. Austria (Laminger, 1975), Congo (Chardez, 1964),
Czechoslovakia (St6panek, 1967), Germany (Grospietsch, 1957), Switzerland, (Penard,
1901), Venezuela (Grospietsch, 1975).

REMARKS. This species was initially described by Penard (1893) and redescribed in more
detail by the same author (Penard, 1 902). The present specimens are in good agreement with
the latter description, including measurements which gave the body length as being generally
between 90-110 um with a few large specimens up to 130 um long. More recently,
Grospietch (1957) has shown a similar regularity in size of specimens from Lake Maggiore,
giving length 90-1 13 um and breadth 48-63 urn. Penard (1902) suggested that this species
was rare in Swiss Lakes, and this appears to be the case in other localities judging by its
reported incidence. Nevertheless, if the two recent reports (Grospietch, 1957 and the
present) are used as indicators, it would appear that when present this species is usually
abundant.

D. mamillaris is distinct in outline, even though the thin structure may be subject to
distortion, and the unusual organic cement pattern.

Difftugia microdaviformis (Kourov, 1925) comb. nov.
Difflugia oblonga var. microdaviformis Kourov, 1925
DESCRIPTION. The shell is brown, pyriform with a distinct aboral protruberance (Fig. 24a). It

C. G. OGDEN

w^S, *

Fig. 23 Difflugia mamillaris: a, lateral view x 1 100; b, apertural view x 790; c, lateral view of
irregular shaped shell x 440; d and e, detail of organic cement network, note the small white
spots in each enclosure which is a regular feature x 24 000.

DIFFLUGIA IN BRITAIN

Fig. 24 Difflugia microclaviformis: a, lateral view x 230, b, apertural view x 530; c, shell surface
illustrating the arrangement of particles and organic cement x2600; d, detail of organic cement
network, note the regular distribution of small pores in each enclosure x 33 000.

is composed of small to medium pieces of quartz, some flattish diatom frustules, and a
network of organic cement is often seen as part of the shell matrix (Fig. 24c). The result is a
smooth surface and a well defined outline. The mesh of the organic cement has a diameter of
300 nm with walls 150nm thick, and a smaller network, with pores about 30 nm in
diameter, covers each mesh enclosure (Fig. 24d). The aperture is circular and surrounded by
small particles (Fig. 24b).

38 C. G. OGDEN

MEASUREMENTS (in um). Based on two specimens: body length 202-206, breadth 88-89,
diameter of aperture 27-28.

MATERIAL EXAMINED. Specimens were collected from a sample of Sphagnum moss gathered
at Holmsley Lodge, Burley, New Forest, Hampshire, in March, 1980.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Argentina
(Vucetich, 1978), Austria (Laminger, 19736), Congo (Gauthier-Lievre & Thomas, 1958),
France (Thomas, 1954), Ivory Coast (Gauthier-Lievre & Thomas, 1958), Mexico (Laminger,
1973a), Roumania (Godeanu et al, 1973), Russia (Kourov, 1925), Spain (Gracia, 1972a).

REMARKS. This species when initially described (Kourov, 1925) had a body length not
greater than 185 urn, whereas Gauthier-Lievre & Thomas, 1958 gave dimensions similar to
those given here. It is redescribed to show its marked similarity to D. claviformis, lack of
material prevents a complete comparison and the identification must be treated as tentative.
D. microclaviformis appears to differ from D. claviformis (see Ogden, 1979) in size and
possibly the organic cement pattern.

Difflugia molesta Penard, 1902

DESCRIPTION. The shell is brown, ovoid or ovoid-elongate, sometimes with a small apertural
collar and arched aborally (Fig. 25a). It is composed of a mixture of quartz particles and
diatom frustules, the former usually being predominant. Organic cement is seen as a network
between particles, either as part of the shell matrix or occasionally at junctions. The rings
that form the network are about 650-750 nm internal diameter with the dividing wall being
100-1 50 nm thick, a second thin, inner wall lies close to the main wall and in the illustrated
specimen the covering membrane is either holed or figured (Fig. 25c). The aperture is
roughly circular, irregular in outline, and mainly surrounded by small particles (Fig. 25b).

MEASUREMENTS (in um). Based on four specimens: body length 106-114, breadth 61-87,
diameter of aperture 28-43.

GEOGRAPHICAL DISTRIBUTION. Roumania (Godeanu et al, 1973), Russia (Kourov, 1925),
Switzerland (Penard, 1902).

REMARKS. These specimens are tentatively identified here as D. molesta, the query arising
due to their similarity with D. amphoralis. Of the four specimens examined, the smallest
(Fig. 25a) bears the closest resemblance being slim, with a small aperture and differing in the
absence of a pointed aboral protruberance. The three broader specimens have a wider
aperture, a narrow neck and are arched aborally. In addition, there are differences in the
organic cement patterns between the two species, but altogether there is insufficient
information to satisfactorily resolve the problem.

Difflugia tricornis (Jung, 1936) comb. nov.
Difflugia elegans forma tricornis Jung, 1936

DESCRIPTION. The shell is pyriform, with a slight broadening near the aperture, and is
characterised by three, evenly spaced, aboral spines (Fig. 26a). The surface is rough and
mainly composed of a mixture of medium and large pieces of angular quartz, the spines have
medium particles at their wide bases but small particles are used progressively as they taper
to a point. Small areas of organic cement are seen between the particles (Fig. 26c), usually in
the form of a regular network (Fig. 26d), having a mesh between 350^00 nm internal

DIFFLUGIA IN BRITAIN

Fig. 25 Difflugia molesta: a, lateral view x910; b, apertural view x740; c, detail of organic
cement to show arrangement of rings and figured centre x 24 000.

diameter and dividing walls about 1 50 nm thick although at some junctions there are larger
areas. The aperture is circular and surrounded by an irregular assortment of particles (Fig.
26b).

MEASUREMENTS (in um). One specimen: body length 1 16, breadth 82, diameter of aperture
40.

C. G. OGDEN

Fig. 26 Dijjlugia tricornis: a, lateral view to show the three equally spaced aboral spines x 690; b,
apertural view x 530; c, portion of shell surface showing small areas of organic cement x2300;
d, detail of organic cement network x 14 000.

MATERIAL EXAMINED. The specimen was collected from aquatic plants taken at the banks of
the River Brett, near Hadleigh, Suffolk in August, 1979.

GEOGRAPHICAL DISTRIBUTION. Germany (Jung, 1936), Sudan (Gauthier-Lievre & Thomas,
1958).

REMARKS. In the earlier descriptions (Jung, 1936; Gauthier-Lievre & Thomas, 1958) the
specimens resembled D. elegans except for the three aboral spines which were stated to be
randomly placed, although Jung (1936) cited Penard's figures referring to much smaller
animals. Differences in the shape and structure of D. elegans examined recently by the

DIFFLUGI A IN BRITAIN 41

author (Ogden, 1979; Ogden & Hedley, 1980) have been confined to the size and structure of
the single aboral spine or horn, whilst the body length was usually of a standard size
110-160 jim.

The present specimen has three, equally spaced, aboral spines and the body breadth is
markedly wider, features that are considered sufficiently different from D. elegans to warrant
a specific designation. The earlier reports are placed, with reservations, in synonymy.

Difflugia ventricosa Deflandre, 1926

DESCRIPTION. The shell is colourless, elongate, with a slight swelling in the aboral half of the
body which then tapers to a sharp point (Fig. 27a). It is composed of a mixture of quartz,
diatom frustules and flagellate cysts to give a thin, irregular surface. Organic cement is
frequently seen between particles in the form of a network (Fig. 27c), made of rings about
600-680 nm in diameter with walls 1 80-250 nm thick (Fig. 27d). In some instances the rings
are fused and appear to have lost or merged their walls (Fig. 27e). The aperture is circular
and usually surrounded by small particles (Fig. 27b).

MEASUREMENTS (in urn). Two specimens: body length 177-199, breadth 64-66, diameter of
aperture 30-3 1 .

MATERIAL EXAMINED. The specimens were collected from a sample of Sphagnum moss
gathered at Holmsley Lodge, Burley, New Forest, Hampshire in March, 1 980.

GEOGRAPHICAL DISTRIBUTION. Belgium (Chardez, 1973), Congo (Gauthier-Lievre &
Thomas, 1958), France (Thomas & Mabille, 1956), Ivory Coast (Gauthier-Lievre &
Thomas, 1958), Venezuela (Deflandre, 1926a).

REMARKS. A redescription of D. ventricosa has recently been given by Chardez (1973) who
compared it with other species having a pointed aboral extremity. It is interesting to note
that he made no comparison with D. venusta, although from the description given here
(below) there would seem to be some similarities. The tabulated measurements given by
Chardez (1973) from earlier descriptions, are in good agreement with the exception of those
given by Thomas & Mabille (1956).

This species is distinct in having a thin, elongate outline which is sharply pointed aborally.

Difflugia venusta (Penard, 1902) comb. nov.

Difflugia pyriformis var. venusta Penard, 1902

Difflugia oblonga var. venusta (Penard, 1902) Cash & Hopkinson, 1909

DESCRIPTION. The shell is pale yellow or hyaline, cylindrical, gradually swelling from the
aperture for about two-thirds of the body length to the broadest diameter and then tapering
sharply in the last third to the bluntly pointed apex (Fig. 28a & b). It is composed mainly of
small to medium pieces of quartz and diatom frustules arranged to give a relatively regular,
intermediate smooth, outline apart from the occasional addition of a larger angular piece of
quartz or diatom frustule. Small areas of organic cement are sometimes visible as a thick
walled network with a covered mesh (Fig. 28d), but more often as thick walled rings about
450-600 nm in diameter and walls 150-220 nm (Fig. 28c). The aperture is usually circular
and surrounded by small particles that give it an irregular margin (Fig. 28c).

MEASUREMENTS (in um). Based on three specimens: body length 174-188, breadth 68-76,

diameter of aperture 30-32.

MATERIAL EXAMINED. Specimens were collected from a sample of Sphagnum moss gathered

at Holmsley Lodge, Burley, New Forest, Hampshire in March, 1980.

GEOGRAPHICAL DISTRIBUTION. Argentina (Dioni, 1970), Belgium (Chardez & Caspar, 1976),

C. G. OGDEN

Fig. 27 Difflugia ventricosa: a, lateral view to illustrate tapering of aboral spine x 520; b,
apertural view x 760; c, shell surface showing small areas of organic cement x4700; d, detail of
organic cement network of rings x 24 000; e, organic cement network with fused rings x 28 000.

DIFFLUGIA IN BRITAIN

Fig. 28 Difflugia venusta: a and b, lateral views to show sharp tapering of aboral region x570
and x340; c, apertural view x590; d, shell surface showing distribution of organic
cement x 9200; e, detail of organic cement network x 24 000.

C. G. OGDEN

mamillaris / \ amphoralis

Fig. 29 Diagrams of pointed species or those with protruberances to illustrate the basic outline,

based on measurements given in Table 3.

DIFFLUGIA IN BRITAIN 45

Table 3 Average dimensions of pointed species or those
with protruberances used to give basic outlines illustrated
in Fig. 29

Species

Length

Breadth

Diameter of
aperture

D. mamillaris

103

D. amphoralis

109

D. molesta

110

D. tricornis

116

D. labiosa

183

132

D. venusta

179

D. ventricosa

188

D. microclavi-

formis

204

D. bicruris

205

106

D. distenda

230

122

France (Thomas, 1954), Haute Volta, W. Africa (Gauthier-Lievre & Thomas, 1958),
Switzerland (Penard, 1902).

REMARKS. The present specimens agree well with the descriptions given by Penard (1902),
Cash & Hopkinson (1909) and Gauthier-Lievre & Thomas (1958) who considered it a
variety of D. pyriformis/oblonga, although the shells described by Cash & Hopkinson (1909)
were slimmer than those reported here and by Gauthier-Lievre & Thomas (1958).

This species is distinct in the graceful outline with bluntly pointed aboral extremity and
shell structure.

Ovoid or spherical species

Difflugia ampullula Playfair, 1918

DESCRIPTION. The shell is hyaline, ovoid and circular in cross section (Fig. 30a). It has a
medium thickness and is composed mainly of small to medium pieces of quartz, arranged to
give a clean outline with a smooth surface. Small areas of organic cement in the form of a
network, are often seen as part of the shell structure (Fig. 30d). The mesh of the network is
small about 300-350 nm in diameter with thin walls 50-100 nm thick, and an even smaller
distinctive network covering each mesh enclosure (Figs. 30e & f)- The aperture is circular,
surrounded by a slightly raised collar of small particles, and the edge of the collar is often
irregular (Figs. 30b & c).

MEASUREMENTS (in urn). Range of 39 specimens: body length 54-95, breadth 35-72,
diameter of aperture 16-29.

MATERIAL EXAMINED. Specimens were collected from aquatic plants taken at the banks of the
River Brett, near Hadleigh, Suffolk in August, 1979.

GEOGRAPHICAL DISTRIBUTION. Australia (Playfair, 1918).

REMARKS. The specimens described here differ slightly from the original description
(Playfair, 1918) in the absence of a 'minute, pointed apiculate process' on the aboral
extremity. However, this process was reported as being present sometimes, and as there is
otherwise good agreement between the two reports, the specimens are designated as D.
ampullula.

C. G. OGDEN

Fig. 30 Difflugia ampullula: a, lateral view x 1000; b, latero-apertural view of aperture to
illustrate the small collar x 1200; c, apertural view x 770; d, portion of shell surface to show the
arrangement of particles and organic cement x5000; e, detail of shell surface x7700; f, small
area of organic cement network, note that each enclosure has an inner network x 25 000.

DIFFLUGIA IN BRITAIN 47

Dijflugia angulostoma Gauthier-Lievre & Thomas, 1958

DESCRIPTION. The shell is transparent, spherical and composed mainly of diatom frustules
(Fig. 3 la & b). The particles are packed close together with many overlapping, to give a
rough surface. Organic cement is seen infrequently as small strands between particles (Fig.
3 Ic). The aperture is usually circular (Fig. 3 la), but it may have irregularities depending on
the arrangement of surrounding diatom frustules.

Two groups of specimens with identical shell features but differing dimensions were
examined, the 'a' specimens are from all four listed localities and 'b' specimens are from

Three Shires Stone only.

MEASUREMENTS (in urn)

body diameter of

length breadth aperture B/L d/L

8 specimens 'a' 40-56 40-48 18-23 0-94 ±0-06 0-42 ±0-06

8 specimens 'b' 60-82 50-73 28-51 0-87±0-09 0-56±0-05

MATERIAL EXAMINED. Specimens were collected from samples of Sphagnum moss gathered
at four localities: Cranes Moor in May, 1977, Holmsley in May, 1978 both in the New
Forest, Hampshire; Three Shires Stone, Wrynose Pass and Lanthwaite, both in Cumbria,
June, 1979.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Argentina
(Vucetich, \913a & b), Congo (Gauthier-Lievre & Thomas, 1958).

REMARKS. This species was described by Gauthier-Lievre & Thomas (1958), from specimens
found in Algeria, who considered that it differed from D. minuta by the large size of the
aperture, quoted as being about one-third of the breadth in diameter, and the covering
diatoms. Both sets of the present specimens, 'a' and 'b', agree well with this description,
having a large aperture about half the breadth diameter and are composed of diatoms. The
'b' specimens share almost similar dimensions to D. angulostoma, the latter having a body
length 60-95 um and aperture 30-45 um, whereas the 'a' specimens are generally smaller.
The difference in size between specimens 'a' and 'b' is more apparent when the ratios d/L are
compared, such differences are usually significant. However, lack of similar data from the
original description of D. angulostoma does not allow a comparison to be made. In the
absence of this information and the otherwise similarity of the two groups of specimens, they
are both designated as D. angulostoma.

Dijflugia decloitrei Godeanu, 1972

Difflugia levanderi Playfair, 1918 (in part)
Difflugia acuminata Levander, 1 894 (in part)

DESCRIPTION. The shell is transparent, ovoid, tapering evenly from the mid-body position
towards the aperture and aboral extremity, there is the suggestion of a collar near the
aperture due to the tapering ending prior to the apertural opening (Fig. 32a). In some
specimens there is an apparent lateral compression, but it is usually slight and probably
related to the fragility of the structure. It has a well defined outline, and the arrangement of
flattish pieces of quartz give it a smooth surface. A network of organic cement is seen at most
junctions of these particles (Fig. 32c). The mesh is about 280-350 nm in diameter and the
walls 350 nm thick (Fig. 32d). The aperture is circular with often a rugged outline due to the
placement of the flattish particles (Fig. 32b).

MEASUREMENTS (in |im). Based on ten specimens: body length 77-95, breadth 39-55,
diameter of aperture 20-27.

C. G. OGDEN

Fig. 31 DiJJlugia angulostoma: a, apertural view x 1600; b, lateral view, note the covering
diatom frustules x 1000; c, shell surface with strands of organic cement x 8700.

MATERIAL EXAMINED. Specimens were collected from a sample of Sphagnum moss gathered
at Myndd Hiraethog, Denbigh, Clywdd, North Wales in August, 1980.

GEOGRAPHICAL DISTRIBUTION. Australia (Playfair, 1918), Germany (Levander, 1894),
Roumania (Godeanu, 1972).

REMARKS. Levander (1894) described four different forms of D. acuminata, one of
which-type 'b'-was considered by Playfair (1918) to represent a distinct species., D.
ievanderi. Both of these authors suggested that there were two sizes of these specimens,
'110x60 and 70x40um', the larger being rough and 'stony' whilst the smaller were
chitinous with small, scattered granules. Recent descriptions of D. Ievanderi, for example

DIFFLUGIA IN BRITAIN

Fig. 32 Difflugia decloitrei: a, lateral view x 1 300; b, apertural view x 900; c, portion of shell to
show arrangement of flat particles to give a smooth surface x2400; d, detail of organic cement
network x 22 000.

that given by Gauthier-Lievre & Thomas (1958) stated a range of body length of 85-140 ^m
suggesting that these are the larger specimens of the earlier authors. The specimens described
by Godeanu (1972) as D. decloitrei appear to be similar to the group of smaller specimens,
having a similar structure and large aperture. Those described here are in good agreement
with this latter description and share similar measurements; body length 62-86 breadth
40-56 and diameter of aperture 20-23 (Godeanu, 1972). In the absence of larger shells for
comparison the present specimens are referred to D. decloitrei.

50 C. G. OGDEN

Difflugia gramen Penard, 1 902

This species has recently been redescribed (Ogden, 1980), but is included here because the
numbers examined allow a comparison of dimensions between specimens from different
habitats and localities. Both samples were collected in August, 1979, from sites which are
about fifty miles apart. Specimens 'A' were selected from a sample of algae and water plants
in stationary water (see Ogden, 1980), specimens 'B' from aquatic plants at the banks of the
River Brett, near Hadleigh Suffolk, which in summer is a slow moving, small watercourse.

MEASUREMENTS (in urn). 'A' thirty-five specimens; 'B' forty-four specimens.

body diameter of

length breadth aperture B/L d/L d/B

'A' 89-117 70-112 23-39 0-96±0-07 0-34±0-04 0-36 + 0-03

'B' 61-97 42-75 18-33 0-77±0-07 0-32±0-04 0-43 ±0-04

avg. 4A' 98-8 94-3 33-6

avg. 'B' 78-7 60-5 26-2

REMARKS. In shell construction the 'A' specimens are larger, spherical and more regular,
only one aperture not appearing typically trilobed. Whilst, 'B' specimens are ovoid and nine
(about 20%) had four lobes or were irregular in outline. It is interesting to note that the
common feature between these specimens is the ratio of the aperture to the body length.

Difflugia masaruzzi Oye, 1958

DESCRIPTION. The shell is transparent, ovoid and composed of a mixture of flattish siliceous
particles including some diatom frustules, to give a fragile structure with an irregular surface
and outline (Fig. 33a). Organic cement is seen at some junctions (Fig. 33c), but there is a
degree of overlapping with most particles. It appears as a network having a mesh of about
450-600 nm in diameter with walls 200 nm thick, each enclosure having a smaller network
with a mesh about 90 nm in diameter (Fig. 33d). The aperture is circular, wide, usually with
an irregular margin (Fig. 33b).

MEASUREMENTS, (in um). Two specimens: body length 66-67, breadth 39^43, diameter of
aperture 25.

MATERIAL EXAMINED. Specimens were collected from a sample of aquatic plants taken from
the edge of a pond at Burley, New Forest, Hampshire in March, 1980.

GEOGRAPHICAL DISTRIBUTION. Congo (Oye, 1958), 'Costa Rica (Laminger, 1973a), Mexico
(Laminger, 1973a).

REMARKS. In the initial description of D. mazaruzii it was stated by Oye (1958) to be similar
to D. rubescens and D. lucida, although it only shares a transparent shell with these two
species. The present specimens agree well with his description of a shell having some large
distinct particles attached, and an aperture devoid of a regular margin more or less wavy
because parts of the shell extend to the edge. Two specimens formed the basis for the earlier
report and were somewhat larger, 72 and 78 |im in body length, 44 and 55 um in breadth, 28
and 30 nm diameter of aperture. Although this species is similar in size to D. glans Penard,
1902 (see p. 7), it is distinct in having a transparent, fragile shell, wide aperture and a
patterned organic cement.

Difflugia mica Frenzel, 1892
DESCRIPTION. The shell is brown, spherical or ovoid with a shallow apertural collar (Fig.

DIFFLUGIA IN BRITAIN

Fig. 33 Difjlugia masaruzii: a, lateral view x 1400; b, apertural view x 1 100; c, shell surface
illustrating the distribution of organic cement x4200; d, detail of organic cement network
x 26 000.

34a). It is composed of small flattish pieces of quartz (Fig. 34d), packed tightly together to
form a strong structure with a smooth surface and positive outline. Only small strands of
organic cement are visible between the particles (Fig. 34e). The aperture is circular and
usually well defined by the collar, which has a thin, even layer of organic cement around it

C. G. OGDEN

Fig. 34 Difjlugia mica: a, latero-apertural view showing the shallow collar x 1600; b, apertural
view, note that the aperture is blocked by a cyst plugx 1 100; c, portion of apertural collar to
illustrate the organic cement covering x3900; d, shell surface with close packing of
particles x 3800; e, detail of organic cement x 24 000.

DIFFLUGIA IN BRITAIN 53

(Figs. 34b & c). The illustrated specimen has a broken cyst membrane, made mainly of
organic cement, just inside the apertural opening.

MEASUREMENTS, (in um). Based on seven specimens: body length 44-58, breadth 36^9,
diameter of aperture 12-1 8; B/L 0-81 ±0-10, d/L 0-31 ±0-05.

MATERIAL EXAMINED. Specimens were collected from a sample of aquatic plants taken at the
banks of the River Brett, near Hadleigh, Suffolk, in August, 1979.

GEOGRAPHICAL DISTRIBUTION. Argentina (Frenzel, 1892), Germany (Schonborn, 1962a & b,
1965), Poland (Moraczewski, 1961, 1965); Roumania (Godeanu et al., 1973), Switzerland
(Penard, 1902).

REMARKS. This species was initially described as Difflugia sp. by Frenzel (1892), the specific
name being added as a footnote (p. 135). In redescribing the species Penard (1902) used the
name D. mica? Frenzel, the query has been dropped by subsequent authors and the name
considered to be valid.

Difflugia microstoma (Thomas, 1954) comb. nov.
Difflugia globularis var. microstoma Thomas, 1954

DESCRIPTION. The shell is ovoid or subspherical, composed mainly of a mixture of small to
medium pieces of flattish quartz and diatom frustules. The particles are arranged to give a
relatively smooth outline (Fig. 35a), with the diatom frustules being in general additions to
the main structure (Fig. 35d). The close packing of materials is such that only small strands
of organic cement are seen (Fig. 35c). The aperture is circular and usually surrounded by a
border of small particles (Figs. 35b & e).

MEASUREMENTS (in um). Based on fifteen specimens: body length 76-105, breadth 63-83,
diameter of aperture 1 8-29; B/L 0-79 + 0-07, d/L 0-26 ±0-03.

MATERIAL EXAMINED. Specimens were collected from Sphagnum moss gathered at Holmsley
Lodge, Burley, New Forest, Hampshire in July, 1978; March, 1980 and at Myndd Hiraethog,
Denbigh, Clwyd, North Wales in August, 1980.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), France (Thomas,
1954).

REMARKS. Thomas (1954) considered when describing the variety D. globularis var.
microstoma that it was similar to specimens of/), globulosa illustrated by Penard (1902, p.
258 Fig. 6), although he later (Gauthier-Lievre & Thomas, 1958) proposed both as
synonyms of D. minuta Rampi, 1950. The examples of D. minuta described in this report
show that D. microstoma is distinct in having a larger ovoid shell with a small aperture
(compare ratios B/L and d/L, below), the latter feature also differentiates it from D. globulosa
Dujardin, 1837.

Difflugia minuta Rampi, 1950

DESCRIPTION. The shell is ovoid or spherical, composed mainly of small pieces of flattish
quartz and the occasional fragment or diatom frustule (Fig. 36a). The particles are packed so
closely, to give a robust structure, that organic cement is visible only as small strands (Fig.
36c). The aperture is small and often surrounded by a narrow lip of organic cement (Fig.
36d), the lip is not apparent in side view but makes the apertural opening distinct when
viewed en face (Figs. 36b & d).

MEASUREMENTS, (in um). Based on six specimens: body length 44-53, breadth 34-48,
diameter of aperture 9-12; B/L 0-98 + 0-08, d/L 0-25 ±0-04.

C. G. OGDEN

Fig. 35 Difflugia microstoma: a, lateral view of shell with smooth surface x980; b, apertural
view x770; c, portion of shell surface with strands of organic cement x 13 000; d,
lateral view of shell with added diatom frustules x 770; e, apertural view x 580.

DIFFLUGIA IN BRITAIN

Fig. 36 DiJJlugia minuta: a, lateral view x 1400; b, apertural view x970; c, portion of shell
surface showing close packing of particles x7700; d, detail of aperture to show narrow lip of
organic cement x3700.

MATERIAL EXAMINED. Specimens were collected from samples of Sphagnum moss gathered
at three locations, Cranes Moor, in May, 1977; Holmsley, in July, 1978, both in the New
Forest, Hampshire; Myndd Hiraethog, North Wales in August, 1980; and aquatic plants
taken at the bank of a pond near Burley, New Forest in March, 1980.

GEOGRAPHICAL DISTRIBUTION. Brazil (Green, 1975), Costa Rica (Laminger, 1973a),
Germany (Schonborn, 1965), Italy (Rampi, 1950), Roumania (Godeanu £/ a/., 1973).

REMARKS. The initial report (Rampi, 1950) of this species is brief, consisting of one
figure and a few lines of description. These note that it has a globular shell made mainly of
quartz particles and concludes that it differs from D. globulosa by its small size, length
53 um, breadth 48 urn. Unfortunately no dimensions for the aperture are given. The
specimens referred to this species by Gauthier-Lievre & Thomas (1958) are all much larger
than the measurements given by Rampi (1950), and are here considered to represent D.
microstoma (see p. 53).

D. minuta is considered a distinct species in having a circular shell composed mainly of
quartz, with a small aperture surrounded by a narrow lip or rim of organic cement.

C. G. OGDEN

Fig. 37 Difflugia rotunda: a, apertural view x270; b, lateral view x240; c, apertural view of
specimen made mainly of quartz particles, note the regular outline of the aperture x290; d,
portion of shell surface of 'diatom' specimen x 3300; e, shell surface of specimen made mainly of
quartz x 2900.

Difflugia rotunda nom. nov.
Difflugia globularis var. sphaerica Chardez, 1956

DESCRIPTION. The shell is brownish, spherical or hemispherical, with the outline frequently
distorted by the addition of large diatom frustules (Figs. 37a & b). The basic structure is made

DIFFLUGIA IN BRITAIN 57

mainly of quartz (Fig. 37c), but diatom frustules or fragments of frustules, are often mixed
with this in different proportions (Fig. 37b). This material is usually packed tightly together
so that only small strands of cement are seen (Figs. 37d & e). The aperture is circular,
sometimes slightly irregular, but usually surrounded by a shallow rim of small particles (Figs.
37a&c).

MEASUREMENTS (in um). Based on sixteen specimens: body length 133-204, breadth
138-193, diameter of aperture 79-1 13; B/L 0-98 + 0-12, d/LO-55±0-07.

MATERIAL EXAMINED. Specimens were collected from samples of Sphagnum moss gathered
at Holmsley Lodge, Burley, New Forest, Hampshire in May, 1978; March, 1979; 1980 and
Myndd Hiraethog, Denbigh, Clwyd, North Wales in August, 1980.

GEOGRAPHICAL DISTRIBUTION. Argentina (Vucetich, \913a & b), Belgium (Chardez, 1956).

REMARKS. In the original description of this variety, D. globularis var. sphaerica, Chardez
(1956) noted that it differed in both size and diameter of aperture, the latter feature being
about half the breadth, from his concept of/), globularis. According to Cash & Hopkinson
(1909) the name globularis was used in error by Wallich (1864) for D. globulosa Dujardin,
1837. Nevertheless, these distinguishing features are used here to differentiate these
specimens from other spherical species. Again a new name is proposed because the term
sphaerica has been widely used for varieties in the terminology of this genus.

ETYMOLOGY. The specific name has been chosen to reflect the shape of the shell (L.
rotunda — round circular or orbicular).

Difflugia stoutii sp. nov.

DESCRIPTION. The shell is ovoid or ovoid elongate, composed of mainly small, flattish
particles of siliceous material, including quartz, diatom frustules and shell plates from
smaller testate amoebae (Figs. 38a & d). It is extremely fragile, several specimens having
collapsed in preparation, and hence the apparent lateral flattening of the specimen shown in
Fig. 38c. Organic cement is seen only as small threads due to the regular overlapping of the
shell components (Fig. 38e). The aperture is roughly circular, small and appears to be
recessed, but this latter feature may be due to structural fragility (Figs. 38b & d).

MEASUREMENTS (in um). Based on four specimens: body length 47-59, breadth 33-36,
diameter of aperture 9-12.

MATERIAL EXAMINED. Specimens were collected from a sample of Sphagnum moss gathered
at Myndd Hiraethog, Denbigh, Clwyd, North Wales in August, 1979.

REMARKS. The present specimens are similar to three species recently described from
Germany, namely D. stechtinensis Schonborn, 1962, D. sudiformis Schonborn, 1966 and D.
szczepanskii Schonborn, 1965. They differ from the two former species in general
dimensions, D. stechtinensis is almost spherical, with an aperturual diameter equal to half
the body breadth, whilst D. sudiformis is an elongate, very slender species. D. szczepanskii is
a slightly larger species but differs mainly in having an aperture size two-thirds of the body
width. All three species are described as having a hyaline shell covered with a meagre
scattering of particles.

D. stoutii is distinct in having a fragile, elongate ovoid shell composed of flattish particles
and a small aperture.

ETYMOLOGY. This species is named after the late Dr John Stout in recognition of his
contributions to recent advances in protozoology.

Difflugia urceolata Carter, 1864
DESCRIPTION. The shell is opaque, ovoid or rotund, often having one or more irregular blunt

C. G. OGDEN

Fig. 38 Difflugia stoutii: a, lateral view x 1 700; b, apertural view x 1 700; c, lateral view ot"
specimen slightly compressed anteriorly x 1 100; d, latero-apertural view of ovoid specimen with
slightly recessed aperture x 1 300; e, shell surface, note the overlapping of particles x 5800.

DIFFLUGIA IN BRITAIN 59

aboral protruberances, and a pronounced apical rim or collar (Fig. 39a). The rim has a
recurved appearance the edge of which is usually well denned (Figs. 39b & c), with an
abundance of organic cement apparent as part of the rim matrix (Fig. 39e). The body is
composed of small to medium particles of quartz, blended together so that the smaller
particles and organic cement fill the gaps between the larger particles and give a relatively
smooth surface. Diatom frustules or parts of them are occasionally included in the structure.
Organic cement in the form of a network is seen as part of the matrix (Fig. 39d), the mesh has
a diameter of about 240-290 nm with walls 100-180 nm thick (Fig. 39f). The aperture is
usually circular (Fig. 39a).

Variation in this species is not uncommon. Although usually limited to the presence or
absence of aboral protruberances, an occasional deformed shell may be seen. The specimen
illustrated here (Figs. 40a & b) has a depressed apical rim, malformed body and defined
aboral protruberances are absent.

MEASUREMENTS (in jim). Based on twenty-one specimens: body length 204-398, breadth
193-^26, diameter of aperture 87-198; B/LO-92±0-10,d/L 0-44 + 0-06.

MATERIAL EXAMINED. Specimens were collected from samples of Sphagnum moss gathered
at Holmsley Lodge, Burley, New Forest, Hampshire on several occasions, May, 1977; 1978
and March, 1980.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Argentina
(Boltovskoy & Lena, 1971, 1974; Dioni, 1970; Vucetich, 19730 & b), Australia (Playfair,
1918), Austria (Laminger, 1972c, 19736), Belgium (Chardez, 1960, 19616; Chardez &
Gaspar, 1976), Brazil (Green, 1975), British Isles (Cash & Hopkinson, 1909; Ogden &
Hedley, 1980), Chile (Decloitre, 1954), China (Decloitre, 1954), Congo (Chardez, 1964;
Stepanek, 1963), Czechoslovakia (Stepanek, 1952), France (Deflandre 1962b; Thomas,
1954), Germany (Jung, 1936), Hungary (Bereczky, 1973), Italy (Grandori & Grandori,
1934), Java (Bartos, 1963a), Netherlands (Hoogenraad & Groot, 1940), Poland
(Moraczewski, 1965), Russia (Kourov, 1925), Spain (Margalef, 1955), Sudan (Gauthier-
Lievre & Thomas, 1 958), Switzerland (Penard, 1 902), United States of America (Laminger et
al, 1979), Venezuela (Deflandre, 19260;Grospietsch, 1975).

REMARKS. This is one of the most widely reported specimens ofDifflugia, probably due to its
size and distinctive shape. However, variation in shell construction has led to the description
of several varieties. Thomas (1954) used the presence of aboral protruberances to
differentiate the variety olla Leidy, 1879; whilst Gauthier-Lievre & Thomas (1958) list four
which differed in rim construction, namely lageniformis (Wallich), lageniformis forma
minor forma nov., minor Deflandre and sphaerica Playfair; and more recently descriptions
of specimens which differed in shape and material have produced two more-var. chayuensis
Wang Jiagi, 1977 and forma subureceola Chardez & Gaspar, 1976.

These reports of natural variation can have little value until they are thoroughly
investigated, and the present specimens are therefore referred to D. urceolata.

Compressed species

Difftugia himethogii sp. nov.

DESCRIPTION. The shell is light yellow or transparent, thin pyriform with a distinct neck or
collar which often has parallel sides (Figs. 4 la & b). The neck region is made of angular
quartz and usually has a rough appearance (Fig. 41b), whilst the remainder of the body is
composed of small to medium pieces of flattened quartz and has a smooth appearance.
Organic cement is frequently seen in small areas as part of the shell matrix (Fig. 4 Id). It is in
the form of a network, made of fused rings each having an internal diameter of about
250-320 nm and walls 200-260 nm thick (Fig. 41e). The aperture is circular and surrounded
by assorted particles of quartz to give it an irregular outline (Fig. 41c).

C. G. OGDEN

Fig. 39 Dijjlugia urceolata: a, apertural view x 180; b, lateral view, note the apertural collar and
small aboral protruberances x 260; c, part of apertural collar, note the well-defined edge of small
particles x 790; d, portion of shell surface to illustrate the distribution of organic cement x 5600;
e, detail of apertural collar shown in c. x 3700; f, detail or organic cement network x 1 5 000.

DIFFLUGIA IN BRITAIN

Fig. 40 Difflugia urceolata specimen with a deformed shell; a, lateral view x 1 70; b,

latero-apertural view x 1 60.

Some of the examined specimens had cyst plugs in their apertural openings. These plugs
varied from being either an uneven mixture of angular quartz (Fig. 42a) or flattish pieces
(Fig. 42b), in both instances the sealing cement was similar to that binding the shell walls
(Figs.42c&d).

MEASUREMENTS (in jim). Based on twenty-six specimens: body length 137-171, breadth
87-1 37, depth 57-84 diameter of aperture 35-52; B/L 0-67 ±0-06, d/L 0-26 ±0-02.

MATERIAL EXAMINED. Specimens were collected from a sample of Sphagnum moss gathered
at Myndd Hiraethog, Denbigh, Clwyd, North Wales in August, 1980.

REMARKS. This species is similar to two other compressed species namely, D. compresscf!
and D. lingula Penard, 1911. Complications regarding the species D. compressa Carter, 1 864
should have been resolved by Cash & Hopkinson (1909) who suggested that from Carter's
figures he was 'beyond question' referring to a species of Pontigulasia. Nevertheless, the
name has been used subsequently to refer to compressed specimens of Difflugia, either as D.
compressa or D. oblonga/pyriformis var compressa. Whether or not there are some genuine
specimens of Difflugia amongst these descriptions is difficult to know, but the name
compressa is preoccupied by Carter's description and is no longer valid, and most refer to
much longer, broader specimens than those described here. The present specimens are
distinct from D. lingula Penard, 1911 and D. lingula var regularis Gauthier-Lievre &
Thomas, 1958 because these have a more rounded shape which tapers sharply from the
mid-body region to the aperture, and D. lingula also has an aboral horn.

D. hiraethogii can be recognised by its lateral compression, distinct circular collar and
aperture.

ETYMOLOGY. This species is named after the area of North Wales in which it was found.

Difflugia lucida Penard, 1890

DESCRIPTION. The shell is transparent, ovoid, gracefully curved aborally but tapering more
gradually towards the aperture to give a well defined outline (Fig. 43a), and laterally
compressed (Fig. 43c). It is thin, smooth and composed mainly of flattish pieces of quartz
with an occasional siliceous shell plate or diatom frustule added, these particles are usually
arranged so that they meet but do not overlap. Small areas of organic cement, in the form of a
network, are seen as part of the shell matrix (Fig. 43d). The network is often an arrangement

C. G. OGDEN

Fig. 41 Dijjlugia hiraethogii: a, lateral view x 730; b, lateral view to illustrate the distinct circular
neck and compressed body x430; c, apertural view x540; d, portion of shell surface showing
small areas of organic cement x 3500; e, detail of organic cement x 1 3 000.

DIFFLUGIA IN BRITAIN

Fig. 42 Difflugia hiraethogii: a, detail of aperture with cyst plug composed mainly of angular
quartz, organic cement at edges x 1 500; b, specimen with cyst plug composed mainly of organic
cement x 1100; c, portion of cyst plug shown in b., note that the particles appear to be well
embedded in organic cement x 3500; d, detail of organic cement of cyst plug x 1 7 000.

of rings whose internal diameter is about 38(M80 nm with walls 95-125 nm thick (Fig. 43e).
The aperture is elliptical and surrounded by irregularly arranged particles which give a
rough outline to the immediate apertural region (Figs. 43a & b).

Several presumably encysted specimens were present in the sample, and easily
distinguished optically by the dark -appearance around the aperture. On detailed
examination this dark area was seen to be a concentration of flat particles projecting from the
apertural openings (Figs. 44a & b).

MEASUREMENTS (in urn). Based on thirty-six specimens: body length 67-91, breadth 40-55,
depth 23-37, diameter of aperture 23-29, depth of aperture 13-19.

MATERIAL EXAMINED. Specimens were collected from a sample of Sphagnum gathered at
Myndd Hiraethog, Denbigh, Clwyd, North Wales in August, 1980.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Argentina
(Vucetich, 1972), Austria (Laminger, 1972a, 19736, 1974, 1975), Belgium (Chardez, 19616;
Couteaux, 1969), British Isles (Cash & Hopkinson, 1909), Bulgaria (Golemansky, 1967),
Canary Isles (Gracia, 1965a & b), China (Bartos 19636), Congo (Chardez, 1964; Stepanek,
1963), Costa Rica (Laminger, 1973a), Czechoslovakia (Rosa, 1957; Stepanek, 1952, 1967),

C. G. OGDEN

Fig. 43 Difflugia lucida: a, lateral view to illustrate basic outline x 1 300; b, apertural view
x 1 100; c, view showing lateral compression and smooth surface x 840; d, part of shell surface
with small areas of organic cement x 5900; e, detail of organic cement network x 23 000.

DIFFLUGIA IN BRITAIN

Fig. 44 Difflugia lucida specimen with cyst plug, note the irregular arrangement of particles in
the apertural opening: a, lateral view x620; b, apertural view x 1 100.

angulostomai \ angulostoma

minuta mica \ stout/ i / \ masaruziil \ decloitrei / \ ampullula

Fig. 45 Diagrams of ovoid, spherical and compressed species to illustrate the basic outline, based
on measurements given in Table 4. Note that D. rotunda and D. urceolata are drawn to the
reduced scale.

C. G. OGDEN

Table 4 Average dimensions of ovoid or spherical species and
compressed species used to give basic outlines illustrated in Fig. 45

Species

Length

Breadth

Diameter of
aperture

angulostoma a.

minuta

mica

stoutii

masaruzii

decloitrei

ampululla

microstoma

rotunda

165

159

urceolata

314

283

143

lucida
hiraethogii

length

76
150

breadth depth

46
104

30
67

diameter of
aperture

17x25
41

France (Thomas, 1954), Germany (Schonborn, 19620 & b\ Guatemala (Laminger, 19730),
Hungary (Varga, 1963), Italy (Grandori & Grandori, 1943; Rampi, 1950), Java (Bartos,
19630; Hoogenraad & Groot, 19406), Mexico (Laminger, 19730), Morocco (Decloitre,
1961), Nepal (Laminger, 19726), Netherlands (Hoogenraad & Groot, 19400), Poland
(Golemansky, 1970; Pateff, 1926), South Shetland Isles (Smith, 1972), Spain (Gracia, 1964),
Switzerland (Penard, 1902).

REMARKS. Some differences in dimensions are worth noting from earlier descriptions; Penard
(1 890) gave a range of body length 50-70 um, but later stated that specimens ranged between
50-60 and rarely greater than 65 um (Penard, 1902), Cash & Hopkinson quoted 60-80 um,
whilst Gauthier-Lievre & Thomas (1958) suggested that there might be three groups (a)
44-50 (b) 55-70 (c) 83-90. In the present group of specimens only seven are outside of the
range 70-80 um and they are remarkable for their similarity.
This species is distinct in having a well defined shape and by being evenly compressed.

Discussion

One of the main difficulties encountered in trying to identify specimens ofDifflugia is due to
the irregular shape of the shell. It is a problem shared with other agglutinate species of
protozoa, such as the foraminifera. In general most species have a regular basic outline,
which may be altered by either natural variation or obscured by the addition of extraneous
material. Both natural and additional variation are probably related to the composition of
the shell, fragile shells being more likely to be influenced by disturbances in the environment
during or after construction, whilst robust shells may be so encrusted by particles that any
resemblance of a specific shape is lost.

Fragile shells are usually made of small particles arranged in a single layer and often have
organic cement as a major component of the shell matrix. In some species a smooth surface
composed of flattish particles is constructed, for example D. mamillaris, where variation in

DIFFLUGIA IN BRITAIN 67

general shape is frequently seen especially in the aboral region (see Fig. 23). Nevertheless, in
a species with a similar surface but different shape, D. lanceolata which is rounded rather
than pointed in the aboral region, there is a relatively constant shape. In the present report a
third of the specimens of D. mamillaris differ from the basic outline given in Fig. 29, whilst
all of the specimens of D. lanceolata agree with the outline in Fig. 1 8. Although robust shells
are usually made of angular quartz which do not lend themselves to being arranged in a
regular manner, if enough specimens of a species is present in a sample it is possible to
illustrate a basic outline. The problems of subsequent recognition of such species from the
basic outline is complicated when the diagnostic feature is obscured by the arrangement of
particles. For instance the diagnostic feature may be the presence of a neck, but if this is
hidden it may be identified incorrectly. Amongst species with this type of shell, examples of
specimens incorporating a single large particle with similar dimensions to the whole shell
have been observed and a not infrequent sight is to see two similar shells united. In these
latter instances the shell is usually of similar size and composition, but these are not
necessarily species of Difflugia but can be other agglutinate forms like Pontigulasia (pers.
observation).

To assist in resolving the question of what represents the basic outline in the species
described here, three sets of line drawings are provided (Figs. 18, 29, 45) which are based on
the average dimensions of the specimens examined.

In the previous studies on pyriform species of Difflugia it has been suggested (Ogden,
1979) that measurements are useful in distinguishing species, with the body length and
diameter of aperture perhaps being the more stable dimensions. However, it was emphasised
that these features alone are not usually sufficient to warrant specific diagnoses. The problem
of using dimensions as a diagnostic character is that they may be valid for a proportion of
species in a genus, but do not hold for all especially in the present instance with a genus
supposedly comprised of over three hundred species. Possibly this is best illustrated by the
variability in size exhibited within a species of testate amoebae, the smallest often being
reported as half the size of the largest, which does not pose problems of identification when
the body length is under 80 um, but for those of larger dimensions the difference between
200 jim and 400 urn can often be interpreted as representing two separate species. The
extreme example is as we have noted previously (Ogden & Fairman, 1979) the range of
measurements quoted for the body length of D. oblonga, 60-580 um, which is so variable
that it could embrace most of the genus or almost all of the described testate amoebae.
Nevertheless, there are examples of consistent dimensions within a species, for instance
those of D. lanceolata and D. mamillaris described here are in good agreement with
previously published results (Penard, 1902; Grospietsch, 1957). The regularity of body
length in D. lanceolata is such that over 87% of the specimens fall within a range of ± 10% of
the average value given in Table 2, whilst in D. mamillaris 96% fall within the same range.

Ovoid or spherical specimens of Difflugia present the same problem. In certain cases
groups of similar species may only be distinguished by dimensions, for example D. anchlora,
D. gramen and D. lobostoma (see Ogden, 1980) which may represent a phylogenetic series.
Whilst is other cases, like the D. globulosa/globularis species complex, size variation is so
great that it is difficult not to include any ovoid or spherical specimen between 50-1 50 um in
this complex. Part of the difficulty is illustrated by the two groups of specimens described
here as D. angulostoma (p. 47), where the shells are identical in construction and essentially
they share the same shape, but there are differences in dimensions especially the diameter of
the aperture. It is possible to separate some of these small spherical species using the latter
feature in addition to other differences, as shown in the descriptions of D. minuta, D. mica
and D. microstoma (see p. 53, p. 50 & p. 53). Structural differences in basic outline as
mentioned earlier are mainly related to shell components and deformities, the former
concerns the choice of materials and will be dealt with later, but the latter using D. urceolata
as an example may be due to its large size. Perhaps it is easier to understand if one considers
that in all probability the shell components are not cemented together until the final shape

68 C. G. OGDEN

has been moulded by cytoplasmic movements. As this process takes about sixty minutes in a
small siliceous species (Ogden, 1981), it will probably take considerably longer in a larger
animal, during which time in a natural environment there is a continual motion
and hence a possibility of disruption. The result of such a disturbance may produce the shell
illustrated in Fig. 40, sufficiently different from normal but not enough for the animal to
abhort and discard the shell prior to the final stiffening of the cement.

Studies on clonal cultures of both siliceous and proteinaceous species (Ogden, 1981 &
pers. observations) show that variation in dimensions are small, differences outside the norm
usually being attributed to abnormal development and even here it is usually below 5%.
Such abnormal development is thought to be associated with cultural differences and not a
frequent natural occurrence. One feature of siliceous species behaviour which may explain
some changes in dimensions, is the occasional production of a shell having a double
complement of shell plates (Hedley & Ogden, 1973). However, this results in an increase in
volume of an ovoid structure, which means that the enlargement in body length is probably
no greater than a third.

At present there are only two reports (Jennings, 1916, 1937) on the development of
Difflugila corona in the laboratory. Both have shown that there can be some variation in
shell construction and until further observations are available on other species of Difflugia,
the question of shell size and composition as diagnostic features will remain a subject of
speculation.

Mention has already been made in the literature of differences in shell construction and
the three categories which are readily identified, robust, intermediate and fragile (Ogden,
1980). But the choice of materials, other than a comment (Ogden, 1980) on the influence of
pH, has not been discussed. That a system of choice is available to the animal is clearly
demonstrated by the composition of certain shells. For example, D. minutissima, D.
lanceolata, D. mamillaris and D. decloitrei all use flattish pieces of quartz, in some instances
small flat particles of diatom frustules may be substituted, but the components used appear
to be restricted in size and thickness. The function of the cytoplasm to identify and select
these particles may appear to be extreme. Nevertheless, it can be measured against the ability
of siliceous testate amoebae to hold each shell plate during shell construction, place it in
position so that there is an even amount of overlap between plates and in some specimens
manipulate spines into definite positions (Ogden, 1981). This selectivity is not restricted to
flat particles, but probably includes the choice of diatoms or angular particles, as well as
mixtures of all types in the composition of Difflugia shells. An additional factor that
influences the choice of particles is undoubtedly the structure and extent of organic cement
in the shell matrix.

It has already been suggested (Ekert & McGee-Russell, 1974) that the organic cement
which binds the shell particles together in Difflugia lobostoma imparts both strength and
flexibility to the structure. This may seem obvious from the different type of shells
constructed by these animals, but it has an importance related to the material used. For
instance, when the cement becomes part of the surface matrix, usually in species with flat
particles, it is found at each facet as part of the shell wall. The strength of the shell is then
directly related to the tenacity of the cement at these junctions.

Furthermore, in species where there is some overlapping of particles the cement is
interwoven with the material and can be likened to the structure of a brick wall, in which the
strength is dramatically increased by the combination of bricks and mortar beyond the
strength of the individual materials assessed on their own. The importance of the organic
cement in shell structure is easily demonstrated by treating a robust individual with either a
chelating agent or concentrated sulphuric acid, in each case within a short time it is reduced
to a small residue of particles. Strength is not directly due to the composition of the acid
mucopolysaccharide material that forms the basic organic cement, but to the properties of
this material. It has already been shown that inorganic elements incorporated with this type
of material in the proteinaceous shells of testate amoebae (Hedley et al, 1976; pers. observ.)

DIFFLUGIA IN BRITAIN 69

and areanceous foraminifera (Hedley, 1963) are thought to strengthen the shell. Some
specimens of Difflugia have been examined by X-ray microanalytical techniques (pers.
observ.), and found to have a significant amount of ferrous iron associated with areas of
organic cement. This probably accounts for the reports of yellow or brown specimens, the
degree of colouration being proportional to the amount of inorganic elements bound to the
organic cement. There is no doubt that the density of this colouration in proteinaceous
specimens can be used as a measure of the degree of reinforcement that the inorganic
elements impart to the structure, newly formed shells being light coloured and fragile, whilst
older shells are dark and strong. This measure can probably be applied to agglutinate forms
as well.

The differences in the network structure of the organic cement are harder to understand,
especially as the examination is limited to surface detail. A need for porosity in some of the
individual organic cement units is puzzling. If they are definite pores to the interior of the
shell they might function as pressure valves for aqueous interchange, because often when the
animal is moving or feeding the apertural opening is completely blocked by cytoplasmic
extrusions. Such a scheme could ensure that the internal volume unoccupied by cytoplasm is
not isolated and allowed to stagnate. Alternatively it may be associated with the hardening
process by inorganic elements. This process seems to be directly related to the environment
and the chemical composition of the cement, the activities of the animal apparently having
no effect on this association. The strengthening process has some degree of justification
because the pores often seen between individual proteinaceous units is newly-formed, light
coloured, shells ofArcella, are not seen in older darker specimens. Examination of the walls
of such specimens show that they are thick and stronger, the implication being that the
inorganic elements have strengthened the shell not the deposition of further organic material
(pers. observ.).

The diversity in the construction of the organic cement units is considered to be a good
taxonomic feature, although they are beyond the limit of optical microscopy, the appearance
of some being particularly unique for example the button-type of D. lacustris (see Fig. 5e
p. 9). The sharing of the same type of unit between different species may suggest some
phylogenetic relationship, possibly linked to the type of shell construction whether smooth,
rough, fragile or strong. However, at present only a quarter of the described species have
been examined and it is too early to make proposals on such relationships. That is apart from
the apparent sharing of the same organic cement pattern between most ovoid species. It is
hoped that further studies in progress on this genus will help to unravel the complications
attributed to describing so many different shapes and forms, and allow a comprehensive
division based on shell structure.

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Manuscript accepted for publication 4 June 1982

Index of species and synonyms

Difflugia

acuminata inflata Penard, 1 899 30

amp hora Leidy, 1879 33
amphoralis Cash & Hopkinson, 1909 27

ampullula Playfair, 1918 45
angulostoma Gauthier-Lievre & Thomas,

1958 47
bicruris Gauthier-Lievre & Thomas,

1958 30

bryophila (Penard, 1902) 2

cylindrus (Thomas, 1953) 5

decloitrei Godeanu, 1972 47

distenda nom. nov. 30

elegans tricornis Jung, 1 936 38

gassowskii nom. nov. 5
glans Penard, 1902

globularis microstoma Thomas, 1 954 53

globularis sphaerica Chardez, 1956 56

gramen Penard, 1902 50

hiraethogii sp. nov. 59

labiosa Wailes, 1919 33

lacustris (Penard, 1899) 9

lanceolata Penard, 1 890 1 1

lemanii Blanc, 1892 26

levanderi Playfair, 1918 47

linearis (Penard, 1890) 11

longicollis(Gasso\vsky, 1936) 5

lucida Penard, 1 890 61

mamillaris Penard, 1893 35

manicata Penard, 1902 16

masaruzziOye, 1958 50

mica Frenzel, 1 892 50

microclaviformis(Kourov, 1925) 35

microstoma (Thomas, 1954) 53

minuta Rampi, 1950 53

Difflugia

minuta minor Godeanu, 1972 22

minutissima Penard, 1904 16

molesta Penard, 1902 38

oblonga bryophila Penard, 1 902 2

oblonga cylindrus Thomas, 1953 5

oblonga elongata Oye, 1953 17
oblonga lacustris Cash & Hopkinson,

1909 9

oblonga linearis Penard, 1 890 1 1
oblonga microclaviformis Kourov, 1925 35

oblonga parva Thomas, 1 954 1 7
oblonga tenuis Wailes & Penard, 1911 24
oblonga venusta Cash & Hopkinson,

1909 41

parva (Thomas, 1954) 17

paulii nom. nov. 1 7

petricola Cash, 1909 20

pristis Penard, 1902 20
pulex Penard, 1902

pyriformis bryophila Penard, 1 902 2

pyriformis lacustris Penard, 1 899 9
pyriformis longicollis Gassowsky, 1936

pyriformis tenuis Penard, 1 890 24

pyriformis venusta Penard, 1902 41

rotunda nom. nov. 56

stoutii sp. nov. 57
tenuis (Penard, 1890)
tricornis (Jung, 1936)
urceolata Carter, 1 864

ventricosa Deflandre, 1 926 4 1

venusta (Penard, 1902) 41

viscidula Penard, 1902 24

Sexangularia

minutissima (Penard, 1 904) 1 6

British Museum (Natural History)

An Atlas of Freshwater Testate Amoebae

C. G. Ogden & R. H. Medley

1980, Hardcovers, 222pp, £17,50 (£18.00 by post). Co-published by British Museum
(Natural History) and Oxford University Press.

This book illustrates, using scanning electron micrographs, most of the common
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The text is designed not only to enable biologists to identify species of testate
amoebae, but to serve as an introduction to students interested in the taxonomy
and biology of these freshwater protozoa. It will be of special interest to
protozoologists, ecologists, limnologists, water treatment specialists and
micropalaeontologists interested in recent sediments.

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Osteology, genitalia and relationships of the Acanthodactylus
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The Opthalmotilapia assemblage of cichlid fishes reconsidered.

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Bulletin of the

British Museum (Natural History)

Miscellanea

Zoology series Vol 44 No 2 24 February 1983

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World List abbreviation: Bull. Br. Mus. nat. Hist. (Zool.)

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The Zoology Series is edited in the Museum's Department of Zoology
Keeper of Zoology : Dr J. G. Sheals
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ISSN 0007-1498 Zoology series

Vol44 No 2 pp 75-1 90

British Museum (Natural History)

Cromwell Road

London SW7 5BD Issued 24 February 1983

Miscellanea

Contents

Cirolana cranchi Leach, 1818 (Crustacea: Isopoda: Cirolanidae) redescribed, with
notes on its distribution. By N. L. Bruce & Joan Ellis

Valettieta, a new genus of deep-sea amphipod (Gammaridea: Lysianassidae) with
descriptions of two new species from the North Atlantic Ocean. By Roger J.
Lincoln & Michael H. Thurston

Three new genera of misophrioid copepods from the near-bottom plankton
community in the North Atlantic Ocean. By G. A. Boxshall

Larval development of British prawns and shrimps (Crustacea: Decapoda: Natantia)
4. Palaemon (Palaemon) serratus (Pennant, 1 777) and functional morphology of
swimming. By A. A. Fincham

The larval development of the Angular Crab, Goneplax rhomboides (Linnaeus)
(Decapoda: Brachyura). By R. W. Ingle & P. F. Clark

The larval and first crab stages of three Inachus species (Crustacea: Decapoda:
Majidae); a morphological and statistical analysis. By Paul F. Clark .

Page

103

125

163

179

Cirolana cranchi Leach, 1818 (Crustacea: Isopoda:
Cirolanidae) redescribed, with notes on its
distribution

Niel L. Bruce

Department of Zoology, University of Queensland, St Lucia, Queensland, 4067, Australia

Joan Ellis

British Museum (Natural History), Cromwell Road, London SW7 5BD

Cirolana cranchi is considered to be the type of the genus Cirolana Leach (by monotypy,
Bruce, 1981) and as Cirolana is the type genus for the family Cirolanidae (Harger, 1880;
Hansen, 1890), the species is of some significance. It comes therefore as some surprise to find
that C. cranchi has not been effectively described since the work of Hansen (1890). The
species has frequently been considered to be indistinguishable from Cirolana parva Hansen
1890 (Stebbing, 1917; Nordenstam, 1946; Monod, 1976), and though these authors have
discussed at some length the similarities of the two species, none resorted to redescription.

Hale (1925) described a variety of Cirolana cranchi from South Australia. Examination of
that species suggested that not only was Hale's variety quite distinct from C. cranchi, but that
several closely similar species exist in the seas around Australia. It was therefore necessary to
examine the holotype and specimens of Cirolana cranchi from England in order to be certain
that none of the Australian species is C. cranchi.

To prevent any further confusion of Cirolana cranchi with C, parva and similar related
species, a new description is given here with full figures, from specimens in the British
Museum (Natural History) collections. The holotype, initially stored in the British
Museum's dry collections (Ellis, 1981) is in extremely poor condition, lacking most
appendages, setae and spines, and is in two pieces. The holotype, taken from Cornwall was
closely compared to Norman's (1904) specimen to assure conspecificity, and the description
and drawings are taken from the latter.

Cirolana cranchi Leach
(Figs 1-3)

Cirolana cranchii Leach, 1818 : 347; Gosse, 1855 : 134, Fig. 230; Hesse, 1866 : 257; Bate & Westwood,
1867:296, Fig. 5; Delages, 1881 : 156; Chevreux 1884:519; Koehler, 1886:25, 61; Bonnier,
1887: 134;Heape, 1888: 1 76; Robertson, 1888 : 76; Hansen, 1890 : 341, PI. 3, figs 3-3i; 1905:350,
PI. 33. fig 3a; Stebbing, 1893 : 343; 1906 : 275; Norman, 1904 : 438; 1907 : 362; Norman & Scott,
1906:40, PI. 4; Monod, 1923: 14; 1930: 137, 145, Figs 2, 5B; 1976: 151; Larwood, 1940:33;
Barrett & Yonge, 1958 : 99, Fig. 59; Crothers, 1966 : 58; Naylor, 1972 : 28, Fig. 9A-C; Ryland &
Nelson-Smith, 1975 : 252; Kussakin, 1979: 191, Figs 71, 72; Bruce. 1981 : 949.

Nelocira swainsonii Leach, 1818 : 347; Desmarest, 1825 : 302, PI. 48, fig. 2.

Eurydice swainsonii: Milne-Edwards, 1840 : 236.

Conilera grampoides Gourrett, 1 89 1 : 1 1 , PI. 1 , fig. 7, PI. 3, figs 4-1 1 .

Cirolana cranchi: Marine Biological Association, 1931 : 183; 1957 : 195; Ellis, 1981 : 123.

Cirolana borealis: Clarke, 1971 : 103 (Non Natatolana &0ra2//s(Lilljeborg)).

Part Cirolana cranchii, Nordenstam, 1946:3, Figs 1-5. [More than one species is involved in
Nordenstam's description.]

Non Cirolana cranchii, Barnard, 1920 : 346; 1940 : 392, 49, 499, Fig. 66; Kensley, 1978 : 65, Fig. 27B,
C.[= Cirolana vicina Barnard, 1914].

TYPE. The holotype is held by the British Museum (Natural History).

Bull. Br. Mus. nat. Hist. (Zool.) 44(2): 75-84 Issued 24 February 1 983

N. L. BRUCE &J. ELLIS

Fig. 1 Cirolana cranchi: (a)-(e), rf 17-0 mm, Polperro; (f) 9 13-3 mm, Polperro; remainder, d
14-0 mm. Plymouth, (a) lateral view; (b) cephalon, dorsal view; (c) pleon and pleotelson, dorsal
view; (d) pleon, lateral view; (e) clypeal region; (0 pleon and pleotelson; (g) pereopod 1 ; (h)
pereopod 7; (i) antennal peduncle; (j) pereopod 1, propodus; (k) pereopod 2; (1) pereopod 2,
dactylus; (m) antennule. Scale line represents 4-5 mm.

CIROLANA CRANCHI

Fig. 2 Cirolana cranchi: all figs d 14-0 mm except (iHO 9 13-3 mm. (a) pleopod 1; (b) appendix
masculina, apex; (c) pleopod 2; (d) pleopod 3; (e) pleopod 2, medial margin of peduncle; (0
pleopod 4; (g) pleopod 5; (h) uropod, ventral view; (i) uropodal exopod, ventral view; (j) uropod,
dorsal view; (k) uropodal endopod, apex; (1 ) uropodal exopod, apex; (m) sternite 7; (n) penes.

N. L. BRUCE &J. ELLIS

Fig. 3 Cirolana cranchi: all figs from cf 14-0 mm. (a) maxilliped; (b) maxillule; (c) right mandible;
(d) antenna, flagellar articles 9-11; (e) antennule, flagellar articles 4-7; (f) left mandible, incisor;
(g) mandibular palp; (h) maxilla.

TYPE LOCALITY. Leach (1818) gives 'Grande Bretagne' as the source of his specimens. Ellis
(1 98 1 ) records the locality as Falmouth, Cornwall.

MATERIAL. 2cf (17-0, 13-3 mm), Polperro, Cornwall. Coll. A. M. Norman. BM(NH) Reg
1911. 11. 8:7840-49. 2rf(14-0, 9-5 mm) 9 (12-6 mm), Plymouth, Devon. Coll. A. M.
Norman. BM(NH) Reg 191 1. 11.8: 7828-30. <S (17-2 mm), 2 9 (13-0, 13-5 mm), Torquay,
Devon. Coll. A. M. Norman. BM(NH) Reg 191 1. 1 1. 8: 7831-33. These specimens form part
of those reported on by Norman (1904).

DESCRIPTION OF MALE. Body about 2-75-3 times longer than wide. Cephalon without rostral
process, interocular carina on anterior margin, dorsal interocular furrow extending from the
dorsal medial margin of each eye; posterior margin of cephalon with groove on each side
indicating presence of maxillipedal somite. Pereonite 1 longest, with 2 horizontal furrows on
each side; pereonites 2-7 approximately subequal in length; coxal plates each with distinct
carina, posterior margins of coxae 5-7 straight, projecting beyond posterior margin of
segment. Pleonite 1 entirely concealed by pereonite 7; pleonite 3 with posterolateral margins
moderately produced, those of pleonite 4 rounded; dorsal surfaces of pleonites with posterior
margins minutely crenulate, pleonite 5 with additional small tubercles. Pleotelson slightly
more than 0-66 as long as greatest width, lateral margins sinuate, converging to narrowly

CIROLANA CRANCHI 79

rounded apex; posterior margins densely setose, with about 21 spines; dorsal surface flat
except for two oblique anterolateral ridges.

Antennule peduncle Inarticulate, articles 1 and 2 appearing fused, although suture
evident; peduncular article 3 equal in length to combined lengths of articles 1 and 2;
flagellum extends to posterior margin of eye. Antenna with peduncular articles 1 and 2 short,
peduncular article 3 about half as long as 4, which in turn is half as long as 5; flagellum
composed of about 38 articles, extends to pereonite 4.

Frontal lamina pentagonal, apex not overlapped by rostral process, lateral margins slightly
concave, diverging slightly, anterior margins straight; about 0-5 times as long as greatest
width. Clypeus about 5-75 times wider than long. Mandibles with asymetrical incisors, that
of right mandible with 3 distinctly formed subequal cusps, that of left mandible with
posterior cusp prominent, central cusp broad and shallow; molar process with about 25
teeth, inferior distal margin setose, lacina mobilis with about 7 spines; mandibular palp with
terminal article curved ventrolaterally, lateral margins with numerous stiff setae. Maxillule
with about 10 stout spines on gnathal surface of exopod, 3 robust plumose setae on proximal
half of medial margin. Maxilliped with continuous marginal setae on palp articles 3-5,
marginal setae on distal margins only of palp article 2; endite with 3 terminal and 3 lateral
plumose setae, and with 2 coupling hooks.

Pereopod 1 with slender spines at posterior distal angle of basis; ischium with 2 setae on
posterior margin and 3 setae at anterior distal angle; merus with about 6 setae at anterior
distal angle, posterior margin with 3 acute spines and 5 tubercular submarginal spines;
carpus with a single spine on posterior margin, set within a conspicuous indentation;
propodus with 2 acute spines on palm, each spine set distally to tooth like projection, third
robust spine opposes dactylus; margin of propodus minutely denticulate between spines.
Pereopods 2 and 3 similar, pereopod 2 with 3 acute spines at anterior distal angle of ischium,
2 blunt spines at posterior distal angle, and third spine on the distal lateral margin; merus
with 5 spines at anterior distal angle, posterior margin bisinuate, with 8 stout spines; carpus
with a single stout spine and single seta on posterior distal angle, spine present on lateral
distal margin; propodus with 3 spines on palm, fourth spine opposing the dactylus; dactylus
with weakly developed but distinct secondary unguis, as in all pereopods. Pereopods 5-7
similar, pereopod 4 intermediate in form between anterior (1-3) and posterior (5-7)
pereopods. Pereopod 7 with about 2 setae and anterior distal angles of propodus, otherwise
without setae; distal angles of ischium, merus and carpus each with a group of spines;
posterior margin of ischium and produs with further 3 groups of 1-4 spines; posterior
margins of merus and carpus with further group of spines; propodus has spine opposing
dactylus.

Penes set together on posterior of sternite 7, separated from each other by about 0-05 the
width of the sternite; penes are not robust, but rather lamellar flaps of cuticle which originate
posteriorly, and project anteriorly, lying against sternite.

Pleopods 3-5 with exopods with partial suture. Peduncles of pleopods 1-5 becoming
progressively shorter towards posterior, peduncle of pleopod 1 twice as wide as long,
peduncle of pleopod 4 3-5 times as wide as long; lateral distal angles each with a single spine,
medial margin 3-5 coupling hooks on pleopods 1-4, pleopod 5 without coupling hooks.
Pleopod 1 with rami subequal in length, endopod with margins parallel, exopod with spine
at proximal lateral angle. Pleopod 2 with endopod fractionally longer than exopod; appendix
masculina arises basally, extends beyond endopod by 0-1 of its length, narrows smoothly to
an acute apex.

Uropods extend distinctly beyond apex of pleotelson. Exopod slightly shorter than
endopod, lateral margin smoothly convex, with continuous marginal setae and about 9
spines, distal half of lateral margin with dense mass of setae extending on to dorsal surface;
medial margin with distinct angle half way along its length, distal half with 6 spines and
dense mass of marginal setae; apex not bifid. Endopod with lateral margin angled at about
0.33 of the way along its length, proximal 0-66 densely setose, setae extending onto dorsal
surface; medial margin convex with dense marginal setae and about 8 spines; apex not bifid.

N. L. BRUCE &J. ELLIS

Fig. 4 Map showing the distribution of C. cranchi. Type locality of Nelocira swainsonii Leach,

18 18 given as Sicily.

FEMALE. The only differences from the male are in the shape of the pleotelson which is wider,
in the shape of the uropods which are not angled, and the lack of the dense setae on the
pleotelson and uropods.

DEVELOPMENT. Young males are similar to females, and the characteristic shape and setation
of the uropods of large males is acquired gradually. One female has oostegites, and measured
13-3 mm.

CIROLANACRANCHI 81

VARIATION. From the specimens examined, it would appear that the minute crenulations on
the pleonites are not visible in large males. The presence and distribution of tubercles on
the dorsal surface of the pleonites is erratic.

SIZE. Hansen (1905) records the largest specimen as a female of 18.0 mm. Museum material
had adult males from 9-0-1 9-1 mm, females ranged from 9-6-1 9-2 mm.

COLOUR. In alcohol, all a pale tan. Barrett and Yonge (1958) describe the colour as 'very pale
grey, minutely dotted on first three segments; rear edge of first seven segments marked by
transverse line'.

REMARKS. The shape and setation of the pleotelson and uropods are unique, and
immediately separate Cirolana cranchi from all other species of Cirolana. Other characters
useful in separation include the shape of the frontal lamina, the shape of the posterolateral
margins of the pleonites, the length and shape of appendix masculina, the shape of the
endopod of pleopod 1 , and the form of the penes.

Cirolana cranchi can be separated from C. parva by the lack of a rostral point, by not
having the frontal lamina overlapped by a rostral projection, and the very different shape,
setation and spination of the pleotelson and uropods.

DISTRIBUTION. Reliably recorded only from the eastern North Atlantic and Mediterranean.
These records are summarized here together with new records from the collections of the
British Museum. Fig. 4 illustrates the present distribution of Cirolana cranchi.

Firth of Clyde: Cumbrae (Bate & Westwood, 1867); Fairland Point, Cumbrae (Robertson,

1888).

Galway Bay, Eire: Spiddal (Ryland and Nelson-Smith, 1975); near Galway (Naylor, 1972);

North Sound (Clark, 197 1 , as Cirolana borealis).

Nymphe Bank: Ballycotton, County Cork, Eire (BM(NH) Collections).

St George's Channel: Dale, Pembroke (Crothers, 1966).

English Channel: Falmouth (BM(NH), holotype); Gwyllyn Vase, Falmouth (Stebbing,

1906); Polperro, Cornwall; Torquay (Norman, 1904); Plymouth, outside breakwater (Bate &

Westwood, 1867); Batten, Mewstone Ledge, Tinside and Stoke Point, Plymouth (Marine

Biological Association, 1957); Knapp Buoy, Plymouth (Heape, 1888); Torbay (BM(NH)

collections); Anstis Cove, near Torquay (Stebbing, 1893); Jersey (Koehler, 1886); off St

Sampson's Harbour, Guernsey (Norman, 1907); Roscoff(Delages, 1881).

Bay of Biscay: Minou, Brittany (Hesse, 1866); Concarneau (Bonnier, 1887);

Grands-Carneaux and east of Belle-Isle, Croisic (Chevreux, 1884); Le Croisic; Belle Isle; He

d'Yeu; Guethery, near Biarritz (Hansen, 1905); Capbreton (Norman, 1904).

Mediterranean: Toulon; Cannes; Porto Vecchio, Corsica; Gabes, Tunis (Hansen, 1905);

Rade d'Hyeres (BM(NH) collections); Brusq, Var (Gourret, 1891, as Conilera grampoides);

Villefranche (Hansen, 1890); Monaco (Monod, 1923); Sicily (Leach, 1818, as Nelocira

swainsonii)', Alexandria (Larwood, 1940).

Discussion

Leach (1818) recorded Cirolana cranchi, the second species of what was to become
the family Cirolanidae. The species then received little attention up to the revision of
the family by Hansen (1890). In that publication and a later one Hansen (1905) reviewed all
previous records. Records published since Hansen's two publications have basically con-
tributed little towards an increased knowledge of the species. Monod (1930) figured the
pleopods, and Kussakin (1979) gave new figures for the antenna, pereopods 1 and 7 and the
male second pleopod, his other figures being taken from Hansen (1890). From this it can be
seen that although the figures given by Hansen (1890) are of a high standard, no modern
description has been given.

82 N. L. BRUCE &J. ELLIS

As a consequence of the lack of detailed description Cirolana cranchi has become
confused with Cirolana parva. The initiator of this confusion was Stebbing (1917)
who considered C. cranchi and C. parva as likely to be synonymous. This opinion
was later followed by Nordenstam (1946) who went to some length to demonstrate
that the two species were one. Unfortunately, he chose to do this by illustrating
pereopod characteristics, the one character likely to lead to the conclusion to which
he came. Pereopods in the genus Cirolana (sens. str. Bruce, 1981) vary very little
between species. Monod (1976) entered the argument in describing a Cirolana sp.
from Togo, West Africa. In this paper Monod reviewed the arguments of previous
authors, and discussed Hansen's (1890) diagnoses. Monod came to the conclusion
that the West African species could be assigned neither to cranchi nor to parva and
nor could they be said not to belong to those species. In effect, that parva and cranchi
are not separable.

When reviewing this debate, the most surprising aspect is that the problem existed
at all. Hansen's (1890) figures clearly separate the two species. The differences in
frontal lamina shape, pleotelson and uropods, presence and absence of rostral process are all
clearly shown. Hansen also states that in parva the uropod apices are bifid, and in cranchi
entire. It also seems remarkable that no author encountering this problem has sought to
redescribe the species involved as a solution. Comparison of the figures, description and
remarks given here to those of Bruce & Bowman (1982) show that Cirolana cranchi and
Cirolana parva are two readily separable species.

As there has been some confusion over the species included under the synonymies
of Cirolana cranchi, the most important of these are now listed and discussed.

Cirolana swainsonii: Miers, 1881. Examination of Miers' specimens shows that they

represent a species related to, but distinct from cranchi that has yet to be described.

Cirolana vicina Barnard, 1914. This species is very similar to C. cranchi and should

be redescribed before final judgement on its status is passed. From Barnard's (1914)

description it differs in having 'sub-bifid' uropod apices, and lacks the dense mass of setae on

the uropods.

Cirolana cranchii var. australiense Hale, 1925. This species is in no way a race or

variety of C. cranchi. It differs in the shape of the frontal lamina, pleotelson and

posterolateral margin ofpleonites2-4, and has a distinct rostral process.

Cirolana cranchii: Nordenstam, 1946. Nordenstam's material came from Europe, South

Africa and the Pacific, and consisted of C. cranchi., C. vicina and a species of

unknown identity from the Pacific.

Cirolana australiense Naylor, 1961. This species is closest to the variety described

by Hale (1925), but may be a distinct species. Naylor's specimens were from the

Chatham Islands, New Zealand.

Cirolana sp.: Monod, 1976. Monod figures two 'Cirolana sp', one from Togo, and

one from the Congo. One of these is Cirolana chaloti Bouvier, 1901 (Bruce, in press),

and the other species may well be new. Monod's (1931) record of C. cranchi may be

of one of these species.

In conclusion, it should be emphasized that in identifying or describing species
related to C. parva and C. cranchi particular care and attention should be given to
details of the frontal lamina, the relative position and shape of the penes, the shape
of the posterolateral margins of pleonites 2-4, the first and second pleopods of the
male, and most importantly details of the pleotelson and uropods.

Acknowledgements

We are grateful to Dr R. J. Lincoln for his comments on the manuscript and for the loan of
specimens to one of us (N. L. B.). This study was supported by a Commonwealth
Postgraduate Study Award to N. L. Bruce.

CIROLANA CRANCHI 83

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1930 Contribution a Petude des 'Cirolanidae'. Annls Sci. nat. (Zool.) (10) 13 : 129-183.

193 1. Sur quelques crustaces aquatiques d'Afrique (Cameroun et Congo). Revue Zool. Bot. afr. 21

1976. Remarques sur quelques cirolanides (Crustaces, Isopodes). Bull. Mus. natn. Hist. nat. Paris

(Zool.) No. 251 : 133-161.
Naylor, E. 1961. Some Isopoda from the Chatham Is., including two species of Cirolana new to New

Zealand. Trans. R. Soc. N.Z. (Zool.) 1 : 7-17.

1972. British Marine Isopods. Synopses Br. Fauna (N.S.) No. 3, 86 pp.

Nordenstam, A. 1946. Marine Isopoda from Prof. Sixten Bock's Pacific Expedition 1917-1918. Ark.

Zool. 37 A (7): 1-31.
Norman, A. M. 1904. British Isopoda of the families Aegidae, Idoteidae, and Arcturidae. Ann. Mag.

nat. Hist. (7) 14 : 430-448.

1907. Notes on the Crustacea of the Channel Islands. Ann. Mag. nat. Hist. (7) 20 : 356-371.

& Scott, T. 1906. The Crustacea of Devon and Cornwall. London (William Wesley & Son),

232 pp.
Robertson, D. 1888. A contribution towards a catalogue of the Amphipoda and Isopoda of the Firth of

Clyde. Proc. nat. Hist. Soc. Glasgow (N.S.) 2 : 9-99.
Ryland, J. S. & Nelson-Smith, A. 1975. Littoral and benthic investigations on the west coast of Ireland.

IV. (Section A: Faunistic and ecological studies.) Some shores in Counties Clare and Galway. Proc.

R. Ir. Acad. 75 Sect. B: 245-266.
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466 pp.
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Africa). Ann. S. Afr. Mus. 17 : 23-46.

Manuscript accepted for publication 14 June 1982

Valettietta, a new genus of deep-sea amphipod
(Gammaridea: Lysianassidae) with descriptions of
two new species from the North Atlantic Ocean

Roger J. Lincoln

Department of Zoology, British Museum (Natural History), Cromwell Road, London
SW7 5BD

Michael H. Thurston

Institute of Oceanographic Sciences, Brook Road, Wormley, Godalming, Surrey GU8 5UB

Introduction

Within the gammaridean family Lysianassidae the combination of a strongly toothed
mandibular incisor and unspecialized gnathopods is shared by only 4 genera, Valettia
Stebbing, 1888, Alicella Chevreux, 1899, Valettiopsis Holmes, 1908 and Valettiella
Griffiths, 1977. Each is monotypic with the exception of Valettiopsis which comprises 4
species, dentata Holmes, 1908, macrodactyla Chevreux, 1909, anacantha Birstein &
Vinogradov, 1963 and multidentata Barnard, 1961. Barnard (1969) included one other
genus, Onesimoides Stebbing, 1888, in his key to lysianassids having a toothed incisor, but
there is some doubt as to the true nature of the mandibular margin. Stebbing (1888), in his
description of O. carinatus says '. . . cutting edge . . . seemingly of the usual form . . .'. In O.
cavimanus, the mandible has '. . . bord tranchant presque simple, renforce a chacun de ses
angles par des bourrelets de chitine. . . .' (Pirlot, 1933), while in O. chelatus the cutting edge
is simple (Pirlot, 1933).

Those genera with a strongly dentate incisor share a broadly similar facies and can be
regarded as forming a natural group, with the omission of Valettia coheres which has a
quite different morphology, especially in the structure of the mouthparts. The choice of
names for these genera has turned out to be rather unfortunate since the genus name Valettia
was used as the stem term for the later taxa Valettiopsis and Valettiella with which it does not
have close affinity.

Valettiopsis and its allies live at moderate to great ocean depths and have as a conse-
quence been infrequently recorded. In fact, all six species were first described from unique
types, and only dentata and macrodactyla have since been redescribed from additional
material (Barnard, 1967; Chevreux, 1935). Recent deep-water collections from the North
Atlantic made during cruises of RRS Discovery and RRS Challenger have produced 5
mature individuals of this rare lysianassid group, one belonging to Valettiopsis
macrodactyla, the other 4 representing two species new to science. The combination of
characters shared by the two new species puts them close to Valettiopsis, but with
sufficient disparity in the configuration of the coxal plates, pereopodal bases, and
mandibular palp armature to justify the erection of a new genus for which we propose the
name Valettietta gen. nov. One existing species of Valettiopsis, namely V. anacantha from
the Philippine Trench in the Pacific, is transferred to the new genus.

Systematics
Family LYSIANASSIDAE

Genus VALETTIOPSIS Holmes, 1908

DIAGNOSIS. Body robust, compressed, pleosome well developed; urosome segment 1 with

Bull. Br. Mus. not. Hist. (Zool.)44(2): 85-101 Issued 24 February 1983

86 R. J. LINCOLN & M. H. THURSTON

large, acute, mid-dorsal tooth, segment 3 broad and dorsally flattened with lateral margins
raised. Antenna 1 and 2 elongate, slender, subequal length, peduncle articles 2-3 of antenna
1 compressed, flagellum article 1 conjoint, accessory flagellum well developed, multi-
articulate. Upper lip weakly notched; lower lip without inner lobes, mandibular lobes
elongate. Mandible having robust incisor, strong spine row interspersed with plumose setae,
and large triturative molar; palp attached level with molar, article 2 elongate with only
distomarginal setae. Maxilla 1 inner plate densely setose along entire inner margin, palp
robust, 2-articulate. Maxilla 2 inner and outer plates subequal length, inner plate with dense
mediodistal and facial setae. Maxilliped basic, outer plate with short inner marginal spines
grading distally to robust elongate spines. Coxal plate 1 much shorter than 2 and partly con-
cealed; plate 4 with only shallow posterior emargination. Coxal plate 5 anterior lobe deeper
than posterior lobe. Epimeral plate 2 distal angle with tooth. Gnathopods 1 and 2 subchelate;
gnathopod 1 palm transverse. Pereopod 7 basis expanded, lacking posterodistal lobe.
Uropods biramous, lanceolate, spinose; uropod 3 outer ramus 2-articulate. Telson deeply
cleft, each lobe with several large apical spines. Branchial lobes bearing small accessory lobe
at the base.

TYPE SPECIES. Valettiopsis dentata Holmes, 1908 (original designation).

REMARKS. Three of the Valettiopsis species names (dentata, anacantha, multidentata) have
been corrected to give the epithets feminine terminations. Holmes (1908) derived the name
Valettiopsis '. . .from Valettia, a genus of Amphipods, and 6vj/is, appearance'. Greek nouns
ending in ops, genitive opsis, are feminine and adjectival specific names must agree in gender
with their genus name (International Code of Zoological Nomenclature, Articles 1 1 (g) (i)
(D,34(b)).

Valettiopsis macrodactyla Chevreux
Valettiopsis macrodactyla Chevreux, 1909 p. 1 , figs 1-2; 1935 p. 8, pi. 2, fig. 1 .

MATERIAL EXAMINED. 1 rf Bay of Biscay abyssal plain, about 47° 15'-28'N 8° 9'^46'W; 4300
metres; collected by Dr A. G. Macdonald during RRS Challenger cruise, October, 1978,
using baited trap. BM(NH) reg. no. 1979 : 8 : 1.

DESCRIPTION. Figs la-h; 2a-h; 3a-k. Length 17 mm. Body robust, compressed, pleosome
segments strongly developed; urosome segment 1 with prominent dorsal tooth, upper margin
of tooth weakly sinous, apex acute. Epimeral plates 2-3 (Fig. 2h) with posterodistal tooth.
Head (Fig. Ib) with triangular lateral lobe apically produced and with sinuous lower margin;
postantennal sinus very shallow; eyes absent. Antenna 1 elongate, peduncle article 1 slender,
longer than 2-3 combined; flagellum 30-articulate; accessory flagellum 9-articulate, reaching
slightly beyond end of basal conjoint article of flagellum; conjoint article of flagellum equal
to length of peduncle, densely setose on inner surface; remaining flagellar articles sparsely
setose. Antenna 2 longer than 1 , peduncle article 5 slightly longer and more slender than 4,
flagellum 40-articulate, proximal flagellar articles with erect setules on inner margin. Upper
lip (Fig. 2a) rounded with minute apical notch. Lower lip (Fig. 2b) outer lobes elongate,
robustly spinulose on inner distal margin; inner lobes absent, mandibular lobes well
developed. Right mandible (Fig. 2c, d), incisor robustly 7-dentate, lacinia also strongly
toothed, comprising two plates with 7 and 4 teeth; spine row with 1 1 large spines
interspersed with long plumose setae, distal spines dentate; molar strongly triturative; palp
robust, article 3 oval with inner distal margin robustly setose, article 2 elongate, inner distal
margin with long setae, inner proximal margin naked. Maxilla 1 (Fig. 2e) inner plate with
entire inner margin densely setose; palp large, article 2 distal margin with stout short spines
and row of submarginal setae. Maxilla 2 (Fig. 20 inner and outer plates subequal, densely
setose, inner plate also with row of facial setae. Maxilliped (Fig. 2g) inner plate with 3 short
apical spines; outer plate inner margin bearing row of spines that are short and stout
proximally grading to elongate and plumose distally; palp elongate, article 3 with row of
strong facial setae, article 4 inner margin bearing 2 short spines.

VALETTIETTA GEN. NOV.

Fig. 1 Valettiopsis macrodactyla Chevreux. Male, a, habitus; b, head and antennae; c, gnathopod
1; d, gnathopod 1, palmar region; e, coxal plate 1, anterodistal margin; f, gnathopod 2; g,
gnathopod 2, palmar region; h, coxal plate 2, posterodistal margin. Bar scales: a, b, 2-0 mm; c, f,
1 -0 mm; d, e, g, h, 0-2 mm.

R. J. LINCOLN & M. H. THURSTON

Fig. 2 Valettiopsis macrodactyla Chevreux. Male, a, upper lip; b, lower lip; c, right mandible; d,
lacinia mobilis and spine row, right mandible; e, maxilla 1 ; f, maxilla 2; g, maxilliped; h, pleon.
Bar scales: a-g, 0-5 mm; h, 2-0 mm.

VALETTIETTA GEN. NOV. 89

Gnathopod 1 (Fig. 1 c, d) subchelate, coxal plate short, triangular, apically rounded, antero-
distal margin with small tooth (Fig. le), distal margin setulose; basis with long setae on
anterior and posterior margins; ischium elongate; merus short with mat of short setules on
posterior margin; carpus little longer than propodus, setose on posterior margin; propodus
rectangular, strongly setose, palm transverse (Fig. Id), delimited by group of stout spines,
palmar margin minutely toothed; dactylus short, slightly overlapping palm, inner margin
with small tooth. Gnathopod 2 (Fig. If, g) subchelate; coxal plate rectangular, posterodistal
margin with 2 small teeth (Fig. Ih); basis with many long setae on anterior and posterior
margins; ischium elongate; merus small; carpus equal to length of propodus, posterior
margin densely setose; propodus robust, densely setose, palm oblique (Fig. Ig) convex,
delimited by group of large dentate spines, palmar margin smooth; dactylus stout with small
tooth on inner margin. Pereopod 3 (Fig. 3a), coxal plate rectangular, distal margin weakly
sinuous, posterodistal angle with 2 small teeth (Fig. 3b); basis curved, merus robust; carpus
shorter than propodus. Pereopod 4 (Fig. 3c) similar to 3, except coxal plate with broad
shallow posterior emargination, distal margin without tooth. Pereopods 5-7 (Figs 3d, e, f)
robust, spinose; basis with tapering posterior lobe, distal angle weakly produced on 5, not
produced on 6-7, bearing 1-2 slender submarginal spines, posterior margin weakly serrate,
distal margin of basal lobe on pereopod 7 bevelled. Uropods biramous, spinose; uropod 1
(Fig. 3g) rami subequal, inner margins of rami minutely serrate; uropod 2 (Fig. 3h) outer
ramus little shorter than inner; uropod 3 (Fig. 3i) distal article of outer ramus about one-third
length of proximal article, inner margin of inner ramus setose. Telson (Fig. 3j) elongate
triangular, cleft to three-quarters length, inner apical margin rounded, outer apical angle
(Fig. 3k) with 4 graduated spines.

DISTRIBUTION. Known only from the North Atlantic in the region of the Azores (Chevreux,
1 935) at 1 692-1 919m, and from the present Biscay record at 4300 m.

VALETTIETTA gen. nov.

DIAGNOSIS. Body robust, compressed; pleosome well developed; urosome segment 1 with
weak dorsal process, segment 3 broad and flattened dorsally with lateral margins raised.
Antenna 1 and 2 elongate, slender, about equal length; peduncle articles 2-3 of antenna 1
compressed, flagellum article 1 conjoint, accessory flagellum well developed, multi-
articulate. Upper lip weakly notched. Lower lip without inner lobes, mandibular lobes
prominent. Mandible with robustly dentate incisor, spine row strong, interspersed with
plumose setae, molar large and triturative, palp attached level with molar, article 2 elongate
with proximal and distal margin setose. Maxilla 1 inner plate densely setose along entire
inner margin, palp robust, 2-articulate. Maxilla 2 inner and outer plates subequal length,
inner plate with dense mediodistal and facial setae. Maxilliped basic; outer plate with short
stout inner marginal spines grading distally to robust elongate spines. Coxal plates 1-4
forming continuous series; plate 4 with deep posterior emargination. Coxal plate 5 anterior
lobe not deeper than posterior lobe. Gnathopod 1 subchelate; palm oblique; gnathopod 2
subchelate or simple. Pereopods 5-7 basis expanded with prolonged rounded posterodistal
lobe. Uropods biramous, lanceolate, spinose. Telson triangular, deeply cleft. Branchial lobes
with small accessory lobe close to base.

TYPE SPECIES. Valettietta lobata sp. nov.

ETYMOLOGY. The affinity of the new genus to Valettiopsis is recognized by adding the
diminutive ending -etta to the common stem. Gender feminine.

Valettietta lobata sp. nov.

MATERIAL EXAMINED. Holotype d, Bay of Biscay abyssal plain, about 47°15'-28'N
8°9'^6'W; 4300 metres; collected by Dr A. G. Macdonald during RRS Challenger cruise
1980, using baited trap. BM(NH) reg. no. 1982 : 204.

R. J. LINCOLN & M. H. THURSTON

Fig. 3 Valettiopsis macrodactyla Chevreux. Male, a, pereopod 3; b, coxal plate 3, posterodistal
margin; c, pereopod 4; d, pereopod 5; e, pereopod 6; f, pereopod 7; g, uropod 1 ; h, uropod 2; i,
uropod 3; j, telson; k, apex of telson lobe. Bar scales: a-f, 1 -0 mm; g-j, 0-5 mm.

VALETTIETTA GEN. NOV.

Fig. 4 Valettietta lobata sp. nov. Holotype. a, habitus; b, head and antennae; c, gnathopod 1 ; d,
gnathopod 1, palmar region; e, gnathopod 2; f, gnathopod 2, palmar region; g, coxal plate 2,
posterodistal margin. Bar scales: a, 5-0 mm; b, 2-0 mm; c, e, 1 -0 mm; d, f, g, 0-2 mm.

R. J. LINCOLN & M. H. THURSTON

Fig. 5 Valetlietta lobata sp. nov. Holotype, a, left mandible; b, left mandible, incisor, lacinia and
spine row; c, right mandible, incisor, lacinia and spine row; d, upper lip; e, lower lip; f, maxilla 1 ;
g, maxilla 2; h, maxilliped; i, pleon. Bar scales: a, d-h, 0-5 mm; b, c, 0-2 mm; i, 2-0 mm.

VALETTIETTA GEN. NOV. 93

Paratype d1, Discovery station 9541 # 19, north west of Cape Verde Islands, RMT 1 +8
combination net, 18 April 1977, 4040-3970 m (fished 0-20 metres off bottom); 20°19-T N
21°51-3' W-20°184' N21°40-5' W. BM(NH) reg. no. 1982 : 205.

ETYMOLOGY. The epithet refers to the expansive posterior lobe of the pereopod basis.

DESCRIPTION. Figs 4a-g; 5a-i; 6a-m. Holotype. Length 21-5 mm. Body robust, compressed,
pleosome segments strongly developed; urosome segment 1 with small rounded median
knob-like process bearing pair of minute apical spinules. Epimeral plate 2 (Fig. 5i) distal
angle quadrate, plate 3 distal angle acute. Head (Fig. 4b) large, lateral lobe triangular,
postantennal sinus very shallow; eyes absent. Antenna 1 elongate, peduncle article 1 slender,
posterodistal angle with small tooth, articles 2-3 short, flagellum 34-articulate; accessory
flagellum 10-articulate, reaching little beyond end of basal conjoint article of flagellum;
conjoint article 1 equal to length of peduncle, densely setose on inner surface, remaining
flagellar articles sparsely setose. Antenna 2 little longer than 1, peduncle articles 4-5
subequal length, flagellum 48-articulate, proximal articles with erect setules on posterior
margin. Upper lip (Fig. 5d) asymmetrically rounded with small apical notch, distal surface
minutely setulose. Lower lip (Fig. 5e) outer lobes elongate, robustly spinulose on inner distal
margin, inner lobes absent, mandibular lobes elongate. Mandible (Fig. 5a, b, c), left incisor
robustly 8-dentate and closely applied to 6-dentate lacinia; right incisor 7-dentate, well
spaced from double bladed lacinia bearing numerous small teeth; spine row with 12-13 large
spines interspersed with long plumose setae, distal spines dentate; molar strongly triturative;
palp robust, article 3 oval with inner margin spinose, article 2 elongate with regular row of
long inner distal setae and irregular groups of shorter proximal setae. Maxilla 1 (Fig. 50 inner
plate with entire inner margin densely setose, outer plate with 2 rows (6 and 5) of pectinate
spines; palp large, article 2 distal margin with stout spines and row of submarginal setae.
Maxilla 2 (Fig. 5g) inner and outer plates subequal, distally setose, inner plate also with row
of facial setae. Maxilliped (Fig. 5h) inner plate with 3 short apical spines, outer plate inner
margin with row of short stout spines becoming gradually more elongated and plumose
distally; palp elongate, article 3 with row of strong facial setae, article 4 inner margin with 2
small teeth. Gnathopod 1 (Fig. 4c, d) subchelate; coxal plate rounded, distal margin with
small tooth, inner distal surface with about 8 groups of setae; basis short, anterior and
posterior mid-margins with long setae; ischium elongate, setose; merus short, margin with
mat of short setules; carpus shorter than propodus and robustly setose; propodus sub-
rectangular, robust, densely setose, palm weakly oblique (Fig. 4d), smooth, delimited by
fan-like group of 6 spines (3 on inner face, 3 on outer face); dactylus short, just reaching to
end of palm. Gnathopod 2 (Fig. 4e, 0 subchelate, longer and more slender than 1 ; coxal plate
subrectangular, posterodistal margin with 2 small teeth (Fig. 4g), inner distal surface with
about 6 groups of 2-5 setae; basis slender, anterior and posterior margins setose; ischium
elongate; merus small; carpus equal to length of propodus, densely setose; propodus sub-
rectangular, setose, palm weakly oblique (Fig. 4f) convex, delimited by fan-like group of 6
spines; dactylus short, not reaching end of palm; gnathopod 2 with characteristic twist in
appendage between basis and merus that reverses the orientation of distal articles. Pereopod
3 (Fig. 6a), coxal plate slender, rectangular, posterodistal angle with 2 small teeth (Fig. 6b);
basis curved; merus elongate slender and much longer than carpus; dactylus small, straight.
Pereopod 4 (Fig. 6c) similar to 3, except coxal plate with broad moderately deep posterior
emargination, posterodistal margin with small notch (Fig. 6d). Pereopods 5-7 (Fig. 6e, f, g),
robust, spinulose; basis broadly expanded with large posterodistal lobe that becomes more
angular from 5 to 7, posterior margin finely serrate; coxal plate of pereopod 6 with posterior
lobe distinctly angular. Uropods biramous; uropod 1 (Fig. 6h) rami subequal, robustly
spinose; uropod 2 (Fig. 6i) inner ramus just shorter than outer, spinose, adjacent margins
minutely serrate; uropod 3 (Fig. 6j) distal article of outer ramus about one-third length of
proximal article, apex with pair of minute inset setules (Fig. 6k). Telson elongate triangular
(Fig. 61), cleft to three-quarters length, inner apical margin acute, outer angle with 2 spines
set in groove (Fig. 6m); dorsal surface of telson flattened with lateral margins downturned.

R. J. LINCOLN & M. H. THURSTON

Fig. 6 Valettietta lobata sp. nov. Holotype. a, pereopod 3; b, coxal plate 3, posterodistal margin;
c, pereopod 4; d, coxal plate 4, posterodistal margin; e, pereopod 5; f, pereopod 6; g, pereopod 7;
h, uropod 1; i, uropod 2; j, uropod 3; k, apex inner ramus of uropod 3; 1, telson; m, apex of
telson lobe. Bar scales: a, c, e-j, 1,1-0 mm; b, d, 0- 1 mm.

VALETTIETTA GEN. NOV.

Fig. 7 Valettietta gracilis sp. nov. Holotype. a, habitus; b, gnathopod 1 ; c, gnathopod 1 palmar
margin; d, gnathopod 2; e, gnathopod 2 propodus, distal margin; f, urosome, telson. Bar scales: a,
2-0 mm; b, d, f, 0-5 mm; c, e, 0- 1 mm.

96 R. J. LINCOLN & M. H. THURSTON

REMARKS. The paratype male, body length 18 mm, has essentially similar morphology to the
holotype; antenna 1 flagellum 25-articulate with especially obvious tooth on peduncle
article 1; antenna 2 flagellum 36-articulate bearing calceoli. The structure of the calceolus
(Fig. 10) was examined by SEM and was found to approximate to the basic lysianassid form
described by Lincoln & Hurley (1981), but with certain unique features that set it apart from
all other lysianassid calceoli described to date. These include the 4 broad crescentic plates
that form the distal element and the lack of a cuticular pit at the point of origin of the stalk
from the flagellar article.

Valettietta gracilis sp. nov.

MATERIAL EXAMINED. Holotype rf, Bay of Biscay abyssal plain, about 47°15'-28'N
8°9'^6'W; 4300 metres; collected by Dr A. G. Macdonald during RRS Challenger cruise
1980, using baited trap. BM(NH) reg. no. 1982 : 206.

Paratype cf, Discovery Station 9541 * 19 north west of Cape Verde Islands, RMT 1 +8
combination net, 18 April 1977, 4040-3970 m (fished 0-20 m off bottom); 20°19-T N
21°51-3' W-20°18-4'N21°40-5' W. BM(NH) reg. no. 1982 : 207.

ETYMOLOGY. The epithet alludes to the slender condition of the gnathopod 2 propodus.

DESCRIPTION. Figs 7a-f; 8a-h; 9a-h. Holotype. Length 1 1 mm. Body compressed, pleosome
segments well developed; urosome segment 1 with rounded median process. Epimeral plates
1-2 posterodistal angle obtuse (Fig. 8h), plate 3 acutely produced. Head large (Fig. 8a),
lateral lobes triangular, apically rounded; postantennal sinus very shallow; eyes absent.
Antenna 1 elongate, flagellum 3 1 -articulate, sparsely setose; accessory flagellum 7-articulate,
reaching beyond end of basal conjoint article of flagellum; conjoint article equal to length of
peduncle article 1 , densely setose on inner surface. Antenna 2 little shorter than 1 , peduncle
articles 4 and 5 subequal length, flagellum 30-articulate, proximal flagellar articles with erect
setules on posterior margin. Upper lip asymmetrically rounded with small apical notch,
distal surface minutely setulose. Lower lip (Fig. 8b) outer lobes elongate, inner distal margin
robustly spinulose, inner lobes absent, mandibular lobes elongate. Mandible (Fig. 8c, d), left
incisor strongly 8-dentate and closely applied to 7-dentate lacinia; right incisor 8-dentate,
well spaced from 6-dentate lacinia; spine row with 13 large spines interspersed with long
plumose setae, distal spines dentate, molar strongly triturative; palp robust, article 1 small,
article 2 extremely elongate with regular row of inner distal setae and irregular groups of
proximal setae, article 3 oval with robust marginal setae. Maxilla 1 (Fig. 8e, 0 inner plate
setose along entire inner margin, outer plate bearing two rows of pectinate spines; palp large,
article 2 distal margin with stout spines and row of long submarginal setae. Maxilla 2 inner
and outer plates subequal, distally setose, inner plate also with row of facial setae. Maxilliped
inner plate with 3 short apical spines; outer plate inner margin with row of short stout spines
(Fig. 8g) becoming gradually elongate and plumose distally; palp elongate, setose.
Gnathopod 1 (Fig. 7b, c) subchelate; coxal plate rectangular, anterior margin angular, distal
margin setose; ischium long and setose; merus small, posterior margin with mat of short
setules; carpus much shorter than propodus, posterior margin densely setose; propodus
elongate, tapering distally, anterior and posterior margins with long setae; palm oblique (Fig.
7c) convex, dentate, delimited by group of short spines; dactylus overlapping palm, inner
margin toothed. Gnathopod 2 simple (Fig. 7d, e), coxal plate rectangular, distal margin
setose, smooth; basis curved, anterior and posterior margins setose; ischium extremely
elongate; merus small; carpus slender, sparsely setose; propodus slender, tapering distally,
margin with groups of long setae that curve inwards to form a setal basket, palm absent but
propodal margin with solitary spine close to the closing point of the dactylus. Gnathopod 2
with characteristic twist in appendage between basis and merus that reverses the orientation
of the distal articles. Pereopod 3 (Fig. 9a) coxal plate rectangular, distal margin setose; basis
curved; merus longer than carpus; propodus and carpus subequal length; all articles with
long marginal spinules. Pereopod 4 (Fig. 9b) similar to 3, except coxal plate very broad and

VALETTIETTA GEN. NOV.

Fig. 8 Valettietta gracilis sp. nov. Holotype. a, head and antennae; b, lower lip; c, left mandible;
d, right mandible; e, maxilla 1 ; f, maxilla 1 palp; g, maxilliped outer plate; h, pleon. Bar scales: a,
h, 1-0 mm;b-g, 0-2 mm.

R. J. LINCOLN & M. H. THURSTON

Fig. 9 Valettietta gracilis sp. nov. Holotype. a, pereopod 3; b, pereopod 4; c, pereopod 5; d,
pereopod 6; e, pereopod 7; f, uropod 1; g, uropod 2; h, uropod 3. Bar scales: a-e, 1 -0 mm; f-h, 0-5

mm.

Fig. 10 Valcttietta lobata sp. nov. Scanning electron micrographs of antennal calceoli; a, b, d
sectional photographs of same calceolus, bar scale: 5-0 (im; c, entire calceolus, bar scale 10 |im.

1 00 R. J. LINCOLN & M. H. THURSTON

deeply excavate posteriorly, distal margin straight and setose; merus and propodus
subequal and longer than carpus. Pereopods 5-7 (Fig. 9c, d, e) robust, spinulose; basis
broadly expanded with large posterodistal lobe that becomes more angular from 5 to 7,
posterior margin minutely serrate; coxal plate of pereopod 6 with subangular posterior lobe.
Uropods biramous; uropod 1 (Fig. 90 and uropod 2 (Fig. 9g) inner ramus shorter than outer,
spinose, adjacent margins minutely serrate; uropod 3 (Fig. 9h) distal article of outer ramus
two-thirds length of proximal article, apex of proximal article with triangular tooth, inner
margin of inner ramus setose, apex of both rami with inset small setule. Telson (Fig. 70
triangular, cleft beyond three-quarters length, apex acute with small spinule.

DISCUSSION. The new genus Valettietta shares a general appearance and many special
features with Valettiopsis, but is characterized by the following combination of characters:
fully developed coxal plate 1; obtuse epimeral plate 2; produced posterodistal lobes on
pereopods 5-7 bases; groups of proximal setae on article 2 of mandibular palp. The species
anacantha described by Birstein & Vinogradov from a deep-sea station in the Pacific south of
the Philippines is transferred to Valettietta; it is very close to gracilis but can be distinguished
by the rounded shape of coxal plate 4 and the presence of a short palm on the propodus of
gnathopod2.

Key to species of Valettiopsis and Valettietta gen. nov.

1 Coxal plate 1 reduced; urosome with strong acute tooth . . . (VALETTIOPSIS) 2
Coxal plate 1 not reduced; urosome lacking strong acute tooth (VALETTIETTA gen. nov.) 4

2. Pereon segments 5-7 and pleosome segments 1-3 dorsally dentate .... multidentata
Pereon segments 5-7 and pleosome segments 1-3

not dorsally dentate 3

3. Gnathopod 2 propodus elongate, tapering dentata

Gnathopod 2 propodus stout, ovo-rectangular macrodactyla

4. Gnathopod 2 simple, or with very small palm, propodus slender, tapering .... 5
Gnathopod 2 subchelate, propodus not slender, ovo-rectangular .... lobata sp. nov.

5. Gnathopod 2 palm oblique, coxal plate 4 distal margin convex anacantha

Gnathopod 2 lacking palm, coxal plate 4 distal margin straight .... gracilis sp. nov.

Valettietta gracilis and V. anacantha can be regarded as vicarious species having disjunct
distributions, one from the Atlantic Ocean and the other from the Pacific Ocean. The
differences separating them, although considered valid at species level, are of a minor nature,
and are much less marked than those separating either species from Valettietta lobata.
Within Valettiopsis, the Pacific species dentata and the Atlantic macrodactyla form a similar
species pair. Other Atlantic/Pacific species pairs are known; Paracallisoma alberti
Chevreux, 1903 and P. coecum (Holmes, 1908), and Crybelocephalus birsteini Thurston,
1976 and C. obensis Birstein & Vinogradov, 1964. The separation of the Atlantic and Pacific
elements of these species pairs may have occurred in the geologically recent past. All are
meso- to abyssopelagic, and have been found in areas that were contiguous prior to the
emergence of the Isthmus of Panama about 3-5 x 106yearsB.P. (Keigwin, 1978).

References

Barnard, J. L. 1961. Gammaridean Amphipoda from depths of 400 to 6000 meters. Galathea Rep. 5 :

23-128.
1967. Bathyal and abyssal gammaridean Amphipoda of Cedros Trench, Baja California. Bull.

U.S. natn. Mus. 260 : 1-205.

1969. The families and genera of marine gammaridean Amphipoda. Bull. U.S. natn. Mus.

271 : 1-535.
Birstein, J. A. & Vinogradov, M. E. 1963. The deep-sea pelagic amphipods of the Philippine Trench.

Trudy Inst. Okeanol. 71 : 8 1-93 (In Russian).
1964. Pelagic gammarids of the northern part of the Indian Ocean. Trudv Inst. Okeanol.

65: 152-195.

VALETTIETTA GEN. NOV. 101

Chevreux, E. 1899. Sur deux especes geantes d'Amphipodes provenant des campagnes du yacht

Princesse Alice. Bull. Soc. zool. Fr. 24: 1 52-1 58.
1903. Note preliminaire sur les Amphipodes de la famille Lysianassidae receuillis par la Princesse

Alice dans les eaux profondes de TAtlantique et de la Mediteranee. Bull. Soc. zool. Fr. 28: 8 1-97.
1909. Diagnoses d'Amphipodes nouveaux provenant des campagnes de la Princesse Alice dans

1'Atlantique nord. Bull. Inst. oceanogr. Monaco 150 : 1-7.

1935. Amphipodes provenant des campagnes du Prince Albert ler de Monaco. Result. Camp.

sclent. Prince Albert I 90 : 1-2 14.
Griffiths, C. 1977. The South African Museum's Meiring Naude cruises. Part 6 Amphipoda. Ann. S.

Afr. Mus. 14(4): 105-123.
Holmes, S. J. 1908. The Amphipoda collected by the U.S. Bureau of Fisheries Steamer 'Albatross' off

the west coast of North America, in 1903 and 1904, with descriptions of a new family and several

new genera and species. Proc. U.S. natn. Mus. 35 : 489-543.
Keigwin, L. D., Jr. 1978. Pliocene closing of the Isthmus of Panama, based on biostratigraphic

evidence from nearby Pacific Ocean and Caribbean Sea cores. Geology, Ashtead6(\0) : 630-634.
Lincoln, R. J. & Hurley, D. E. 1981. The calceolus, a sensory structure of gammaridean amphipods

(Amphipoda: Gammaridea). Bull. Br. Mus. nat. Hist. (Zool.) 40 (4) : 103-1 16.
Pirlot, J. M. 1933. Les amphipodes de 1'expedition du Siboga. Deuxieme partie. Les amphipodes

gammarides. II. Les amphipodes de la mer profonde. I. Siboga Exped. 33c (1 20): 1 1 5-1 67.
Stebbing, T. R. R. 1888. Report on the Amphipoda collected by H.M.S. Challenger during the years

1873-1876. Rep. sclent. Results. Voy. Challenger (Zoology) 29 : 1-1737.
Thurston, M. H. 1976. New pelagic amphipods (Crustacea: Amphipoda) collected on the Sond cruise.

J. mar. biol. Ass. U.K. 56: 143-159.

Manuscript accepted for publication 10 June 1982

Three new genera of misophrioid copepods from the
near-bottom plankton community in the North
Atlantic Ocean

G. A. Boxshall

Department of Zoology, British Museum (Natural History), Cromwell Road, London
SW7 5BD

Introduction

Only three species of the copepod order Misophrioida have been described, Misophria
pallida Boeck 1864, Benthomisophria palliata Sars 1909 and B. cornuta Hulsemann & Grice
1964. Despite the small number of species the misophrioids have attracted interest because
of the combination of characters that they exhibit, drawn from both the gymnoplean and
podoplean lineages within the Copepoda. Attention has recently been drawn to the unique
characters that misophrioids display; the possession of a carapace-like posterior extension of
the cephalosome, the lack of a nauplius eye in a free living copepod, the distensibility of the
gut and the retention of the antennary glands as the functional excretory organs of the adult
(Boxshall, 1982). These characters, together with the abbreviated lecithotrophic nauplius
phase of the life cycle, can be interpreted collectively as evidence of a bathypelagic origin of
the Misophrioida. This interpretation is supported by the discovery of several new
misophrioid taxa from the deep North Atlantic Ocean, which was reported at the First
International Conference on Copepoda held at Amsterdam in August 1981 (Boxshall, in
press).

A total of 37 misophrioids was taken in a single haul fished near the bottom in 3000 m of
water to the south west of the Azores. Fourteen of these were B. cornuta, 8 were B. palliata
and 15 represented previously undescribed taxa. Three new genera and species are here
described on the basis of 13 of these specimens, the remaining 2 specimens being too badly
damaged for description. The new genera are of great phylogenetic significance as they
exhibit some very plesiomorphic characters which provide fresh insights on the nature of the
appendages of the common ancestor of the Copepoda as a whole. The new records of B.
cornuta and B. palliata further extend their known geographical ranges.

Family MISOPHRIIDAE

Genus ARCHIMISOPHRIA nov.
DIAGNOSIS. As for type species.
TYPE SPECIES. Archimisophria discoveryi gen. et sp. nov.

Archimisophria discoveryi gen. et sp. nov.

Adult female (Fig. 1A) body length 1-1 to 14 mm. Prosome large, apparently 4-segmented
but with first free thoracic somite entirely concealed beneath a carapace-like extension from
the posterior margin of the maxilliped-bearing somite. Nauplius eye absent. Prominent
anteriorly-directed rostrum visible from dorsal aspect, not fused to labrum (Fig.
1 B). Cone organs not observed but large mass of glandular tissue present on sides of
cephalosome beneath usual location of cone organs. Urosome 6-segmented (Fig. 1C). Surface

Bull. Br. Mus. nat. Hist. (Zool.) 44(2): 103-124 Issued 24 February 1983

104

G. A. BOXSHALL

Fig. 1 Archimisophria discovery! gen. et sp. nov. Holotype 9. A, dorsal view; B, rostrum and
labrum, ventral; C, urosome, ventral; D, antennule, dorsal. Scales 100 urn unless otherwise
stated.

MISOPHRIOID COPEPODS 105

of prosome and urosome somites 1 to 5 ornamented with a reticulum of epicuticular
lamellae. Urosome somite 6 without reticulate markings. Caudal rami longer than wide;
armed with 2 long distal margin setae, 2 medium-length distal angle setae, a dorsal seta near
the inner margin and a distally located lateral seta.

Antennule (Fig. ID) 27-segmented, articulating proximally with an expanded area of
ventral cephalic surface (Fig. IB). Armature elements as follows: 1-2, II-2, III-2+1
aesthetasc, IV-2, V-2, VI-2, VII-2 + 1 aesthetasc, VIII-2, IX-2, X-2, XI-2+1 aesthetasc,
XII-2, XIII-2, XIV-2, XV-2, XVI-2+1 aesthetasc, XVII-2, XVIII-2, XIX-2, XX-2,
XXI-2, XXII-1, XXIII-1, XXIV-2, XXV-2, XXVI-2 + 1 aesthetasc, XXVII-5+1
aesthetasc. First segment also with patch of minute spinules.

Labrum (Fig. IB) small, posteriorly directed, not fused with rostrum, with a posterior row
of marginal denticles.

Antenna (Fig. 2A), basis lacking inner distal seta; endopod 3-segmented, exopod 8-
segmented. Endopod segment 1 apparently unarmed; segment 2 with 4 unequal unilaterally
plumose setae at inner distal angle; segment 3 with 6 long subequal unilaterally plumose
setae along distal margin and with several transverse rows of spinules. Exopod segment 1
with a short naked seta at inner distal angle; segments 2 and 3 unarmed; segment 4 with a
long plumose seta at inner distal angle; segment 5 with 2 long plumose setae on inner margin;
segments 6 and 7 small, unarmed; segment 8 with 3 long unilaterally plumose setae on distal
margin and areas of spinules subapically.

Mandible (Fig. 2B) with well developed gnathobase bearing distally 2 multicusped blades,

5 strong spines and an extensive fringe of pinnules. Mandibular palp comprising basis,
2 -segmented endopod and 4-segmented exopod. Basis armed with a naked seta at inner distal
angle. Endopod segment 1 with a short unilaterally plumose seta at inner distal angle;
segment 2 with 8 unequal plumose setae along distal margin. Exopod segment 1 unarmed;
segments 2 and 3 each with 1 long seta at inner distal angle; segment 4 with 3 similar
unilaterally plumose setae and a short naked seta.

Maxillule (Fig. 2C), gnathobase with 14 distal elements; endite 1 with 1 spiniform and 3
setiform armature elements, endite 2 with 3 spiniform elements. Outer lobe rudimentary,
represented by 6 plumose setae on outer surface of segment. Maxillulary palp biramous with
2 -segmented endopod and 1 -segmented exopod. Endopod segment 1 with 3 unequal
armature elements at inner distal angle; segment 2 with a long and a short seta proximally on
inner surface and an apical armature of 3 long unilaterally plumose setae, 1 long and 2 short
naked setae. Exopod with a proximal fringe of pinnules and 6 plumose setae on inner margin
and with 3 long unilaterally plumose setae and a naked seta on distal margin.

Maxilla (Fig. 3A) 6-segmented; segment 1 with 6 plumose setae on proximal endite and 3
on distal endite; segment 2 with 3 similar setae on both proximal and distal endites; segment
3 produced medially into a curved claw armed with 3 naked setae near its base; segments 4 to

6 with a total of 10 setae.

Maxilliped (Fig. 2D) 8-segmented, with a 3-segmented, robust proximal portion and a
slender 5-segmented distal portion. Segment 1 with 1 seta on inner surface; segment 2 with 2
medial setae and a row of pinnules along the outer margin; segment 3 with proximal endite
bearing 1 strong spine and 3 setae, distal endite with 1 naked seta and a long plumose seta, 2
other setae on inner margin, a plumose seta at inner distal angle and a long row of pinnules
along outer margin; segments 4 to 6 with 1, 2 and 1 medial setae respectively, each armed
with short spinules; segment 7 with an inner margin spinulate seta and an outer plumose seta
on which the pinnules decrease markedly in length towards the apex; segment 8 with 3
similar plumose setae and a naked seta.

Legs 1 to 4 incomplete in holotype 9 and paratype 9, assumed to be similar to those
described below for a paratype rf.

Leg 5 (Fig. 1C) uniramous, 3-segmented and positioned midventrally with inner margins
almost touching at base. Segment 1 with 1 naked seta at outer distal angle; segment 2 with a
short naked seta in same position; segment 3 elongate with 2 unequal distal margin setae, the
longer armed with spinules bilaterally.

G. A. BOXSHALL

Fig. 2 A. discoveryi. A, antenna, anterior; B, mandible, anterior; C, maxillule, posterior; D,
maxilliped, posterior. Scales 100 |im unless otherwise stated.

MISOPHRIOID COPEPODS

107

Fig. 3 A. discoveryi. A, maxilla, anterior; B, Paratype cf, dorsal view; C, urosome, ventral; D,
antennule, dorsal. Scales 100 fim unless otherwise stated.

108 G. A. BOXSHALL

Leg 6 (Fig. 1C) reduced to a semicircular flap closing off the opening of the genital antrum;
bearing an outer plumose seta and a short inner spine.

Adult male (Fig. 3B) body length 1-1 to 1-3 mm (based on 3 specimens). Prosome and
urosome (Fig. 3C) as in adult female. Appendages as in female except for antennules and legs
5 and 6.

Antennules (Fig. 3D) 25-segmented, unigeniculate with the articulation between segments
XIX and XX. Armature elements as follows: 1-2, II-2, III-2, IV-2, V-2, VI-2, VII-2, VIII-2,
IX-2, X-2, XI-2 + 1 aesthetasc, XII-2, XIII-2, XIV-2, XV-4, XVI-2+1 aesthetasc,
XVII-2, XVIII-2, XIX-2, XX-0(?), XXI-1, XXII-2, XXIII-2, XXIV-2+1 aesthetasc,
XXV-3 + 1 aesthetasc. Segment XIII with a spinous process at posterolateral angle.

Legs 1-4 (Figs 4A-D) biramous with 3-segmented rami; armature formula as follows:

coxa basis endopod exopod

legl 0-1 1-1 0-1;0-1;1,2,3, I-1;I-1;III,I,3

leg 2 0-1 1-0 0-1;0-2;1,2,3 I-1;I-1;1 11,1,4

leg 3 0-1 1-0 0-1;0-2;1,2,3 I-1;I-1;III,I,4

Ieg4 0-1 1-0 0-l;0-2;missing I-1;I-1;1 11,1,4

Pinnule rows present on inner and outer margins of endopod segments and inner margins of
exopod segments; spinules present along margins of exopod segments. All outer margin
exopodal spines armed with bilateral strips of fine membrane, apical spine with membrane
externally and pinnules internally. All setae plumose except for distalmost 2 inner margin
setae on exopod of leg 4. These setae with blunt tips and rows of short stout pinnules,
possibly representing a male dimorphic character.

Leg 5 (Fig. 4E) uniramous, 4-segmented and with bases of legs almost touching at ventral
midline as in 9. Segment 1 bearing 1 plumose seta at outer distal angle; segment 2 with naked
seta in same position; segment 3 with plumose seta at inner distal angle; segment 4 with short
inner margin plumose seta and 2 unequal plumose setae on distal margin.

Leg 6 (Fig. 3C) represented by a flattened plate bearing a long outer plumose seta and a
short inner spine.

MATERIAL EXAMINED. Holotype 9, 3 paratype cfd1, 19,2 Copepodid IV and 3 Copepodid III
stages all from Discovery Stn 10379*37 (34°5T N 32°55' W) in the North Atlantic to the
southwest of the Azores. Collected in RMT1+8M net system fished 23 to 56 m off the
bottom in a water depth of about 3000 m. BM(NH) Registration Nos Holotype 9 1982.128,
paratype 9 1982.129, rfrf 1982.130-132,Co. IV 1982. 133-134 and Co. Ill 1982.135-137.

REMARKS. The new genus differs from all known misophrioids, including those described
herein, in the possession of an anteriorly directed rostrum. In other genera the rostrum is
either ventrally directed (Misophria and Misophriopsis gen. nov.) or postero ventral ly
directed and fused to the labrum (Benthomisophria and Misophriella gen. nov.). Another
remarkable feature of this genus is the large number of segments in the antennules of both
sexes. The twenty-seven segments found in the female is the largest number recorded for any
copepod, including the calanoids in which 25 is the largest number known. The
phylogenetic significance of the multi-segmented antennules is discussed below.

The developmental stages of A. discovery! will not be described as only the third (Co. Ill)
and fourth (Co. IV) copepodid stages have been found. As in other misophrioids (Boxshall &
Roe, 1980) the copepodid stages can be determined by the number of urosome somites, the
Co. Ill having 3 and the Co. IV having 4. It is interesting to note that the segmentation of the
antennule is complete (27 segments) at the Co. IV stage whereas in Benthomisophria palliata
the complete complement of 1 8 segments is not achieved until the last moult into the adult.
The third copepodid of A. discoveryi has a 24-segmented antennule.

The presence of a 3-segmented leg 5 in female and 4-segmented leg 5 in male A. discoveryi

MISOPHRIOID COPEPODS

109

Fig. 4 A. discoveryi. A, leg 1 , anterior; B, leg 2, anterior; C, leg 3, anterior; D, leg 4, anterior; E,
leg 5, anteroventral. Scales 100 urn unless otherwise stated.

110 G. A. BOXSHALL

is the first documented example of sexual dimorphism in the fifth leg in misophrioids. In
Misophria and Benthomisophria sexual dimorphism is restricted to the antennules and sixth
legs. The presence of modified setae on the inner margin of the third exopod segment of leg 4
in male A. discoveryi may also represent sexual dimorphism but this cannot be confirmed
until more material is obtained, as the only 2 females in the present material had incomplete
fourth legs.

Genus MISOPHRIELLA nov.

DIAGNOSIS. As for type species.

TYPE SPECIES. Misophriella tetraspina gen. et sp. nov.

Misophriella tetraspina gen. et sp. nov.

Adult female (Fig. 5 A) body length 0-87 mm (Holotype 9). Prosome apparently 4-segmented
but, as in all misophrioids, with the first free thoracic somite entirely concealed beneath a
carapace-like extension of the posterior margin of the maxilliped-bearing somite. Nauplius
eye absent. Rostrum posteroventrally directed and fused to anterior surface of labrum, not
visible from dorsal aspect. Cone organs present in lateral areas on cephalosome. Urosome
6-segmented (Figs 6A-B), somites 2 to 5 each with a hyaline frill around posterior border.
Anal somite with paired lobes dorsally, either side of anus and row of minute spinules
around posterior margin. Pairs of pores present on both dorsal and ventral surfaces of anal
somite. Caudal rami about as long as wide, armed with 2 long distal margin setae, 2 medium
length distal angle setae, a dorsal seta near the distal margin, a seta near the middle of the
lateral margin and a proximal setule on this margin.

Antennule (Fig. 5B) 19-segmented, articulating basally with a raised area of ventral
cephalic surface. Armature elements as follows: 1-1, II-9, III-2, IV-2, V-6, VI-2, VII-2,
VIII-2, IX-2+ 1 aesthetasc, X-2, XI-2+ 1 aesthetasc, XII-2, XIII-2, XIV-2 + 1 aesthetasc,
XV-1, XVI-1, X VII-2, X VIII-2 + 1 aesthetasc, XIX-6+ 1 aesthetasc. Segment I with 1 and
segment II with 3 strong curved setae, each strongly sclerotized with an expanded base and a
row of spinules along its convex margin.

Labrum large, posteriorly directed and fused with rostrum.

Antenna (Fig. 5C); basis with inner distal seta; 3-segmented endopod and 6-segmented
exopod. Endopod segment 1 with a short plumose seta at inner distal angle; segment 2 with 2
short naked setae near middle of inner margin and a long and a short seta at inner distal
angle; segment 3 with 6 long unilaterally plumose setae along its distal margin. Exopod
segment 1 unarmed; segments 2 to 5 each with a single long, unilaterally plumose seta on its
inner margin; segment 6 with 2 similar setae and a short plumose seta on its distal margin.

Mandible (Fig. 7A) with well developed gnathobase bearing 4 multicusped blades and
some pinnules distally. Mandibular palp comprising basis, 2-segmented endopod and
4-segmented exopod. Basis apparently lacking inner distal angle seta. Endopod segment 1
with 1 naked seta at inner distal angle; segment 2 with 1 short naked seta and 4 long plumose
setae apically. Exopod segment 1 unarmed; segments 2, 3 and 4 with 1 , 2 and 3 long plumose
setae respectively.

Maxillule (Fig. 7B) with armature of gnathobase reduced, comprising only 7 curved
spinous elements, 1 hirsute seta and 2 slender naked setae. Endites 1 and 2 with 5 and 4
slender setae respectively; all setae sparsely armed with short spinules bilaterally. Outer lobe
apparently absent. Maxillulary palp biramous with 1 -segmented exopod and 3-segmented
endopod. Endopod segment 1 fused to basis, with 3 unequal plumose setae at inner distal
angle; segment 2 with 2 inner margin plumose setae; segment 3 small, bearing 4 unequal
setae apically. Exopod with 3 long plumose setae distally and a short plumose seta and a row
of pinnules along inner margin.

Maxilla (Fig. 7C) 6-segmented; segment 1 with 2 hemispherical endites, proximal endite
with 1 naked and 4 plumose setae, distal endite with 2 spinulate setae; segment 2 with a

MISOPHRIOID COPEPODS

111

Fig. 5 Misophriella tetraspina gen. et sp. nov. Holotype 9. A, dorsal view; B, antennule, dorsal;
C, antenna, anterior. Scales 50 Jim unless otherwise stated.

112

G. A. BOXSHALL

Fig. 6 M. tetraspina. A, urosome, dorsal; B, urosome, ventral. Scale 100 |im.

single elongate endite bearing 3 unequal naked setae at its apex; segment 3 produced into a
long medial claw with a fringe of minute pinnules along its concave margin and 3 setae near
its base; segments 4 to 6 each with 1 long, robust claw-like seta armed with a fringe of
pinnules, segment 6 also bearing 2 slender apical setae.

Maxilliped (Fig. 7D) 7-segmented; segments 1 and 2 long and robust. Segment 1 armed
with 1 proximal seta, 3 midmargin setae and 2 distal setae all on inner margin; segment 2
with 3 slender setae at middle of inner margin; segments 3 to 5 with 1, 2 and 1 slender inner
margin setae respectively; segment 6 with an articulated seta distally and segment 7 with 2
similar articulated setae, plus 2 short naked setae.

Legs 1-4 (Figs 8 A-D) biramous, presumably with 3-segmented rami; armature formula as
follows:

legl
leg 2
leg 3
leg 4

coxa

0-1

basis
1-1
1-0
1-0
1-0

endopod
0-1 ;0-2; 1,2,3
0-1 ;missing
0-l;0-2;missing
0-l;0-2;missing

exopod

I-l;missing
I-l;missing

Pinnule rows present on inner and outer margins of endopod segments and on inner margins
of exopod segments. Leg 1 with accessory digitiform processes on outer margin of exopod
segments 2 and 3 between bases of spines. Exopod spines armed with bilateral strips of
serrate membrane.
Leg 5 (Fig. 8E) uniramous, 4-segmented. Segment 1 broader than long, unarmed; segment

MISOPHRIOID COPEPODS 113

2 broader than both segments 1 and 3, armed with a naked seta on outer margin; segment 3
with spinous process at outer distal angle; segment 4 with 1 plumose seta either side of
central spine in distal margin, also with an inner margin plumose seta on left leg but not on
right.

Leg 6 (Fig. 6B) forming a curved plate on ventral surface of genital somite; armature
incomplete.

MATERIAL EXAMINED. Holotype 9 collected at Discovery Stn 10379*37 (34°57 N 32°55'W)
in the North Atlantic southwest of the Azores. Caught in RMT1 + 8M net system fished 23
to 56 m off the bottom in a water depth of about 3000 m. BM(NH) Registration No.
1982-138.

REMARKS. The new genus differs from all known misophrioids, including those described
herein, in the form of the maxillule (which has a 3 -segmented endopod, no outer lobe and an
elongate exopod bearing only 4 setae), in the presence of only a single endite on the second
segment of the maxilla and in the number of segments in the antennule. This genus exhibits a
general reduction in the numbers of armature elements on most of the mouthparts, particu-
larly on the maxillulary palp and the maxilla. In addition to these quantitative differences
there are also qualitative differences, such as the spiniform nature of 4 setae on the proximal
segments of the antennule and the presence of articulated setae on the maxilliped.

The armature elements of the fifth legs provide some indication of the homology of the
segments. The second segment carries an outer seta at its distal angle and it is also much
wider than the other segments. It probably represents the basis. Segment 1 therefore
represents the coxa, and segments 3 and 4 the 2-segmented exopod. The holotype exhibits
bilateral asymmetry in the armature of leg 5 but it is assumed that this is an aberrant con-
dition and is not indicative of a true asymmetry as displayed by the fifth legs of many
calanoids.

Genus MISOPHRIOPSIS nov.
DIAGNOSIS. As for type species.
TYPE SPECIES. Misophriopsis dichotoma gen. et sp. nov.

Misophriopsis dichotoma gen. et. sp. nov.

Adult female (Fig. 9 A) body length 0-9 mm (Holotype 9). Prosome apparently 4-segmented
but with first free thoracic somite entirely concealed beneath a carapace-like extension from
the posterior margin of the maxilliped-bearing somite. Nauplius eye absent. Rostrum small,
ventrally directed with its apex adjacent to, but not fused to, the labrum (Fig. 12). Cone
organs present in lateral areas on either side of cephalosome. Urosome (Fig. 9B)
6-segmented. Caudal rami wider than long, armed with 2 long distal margin setae, a medium
length seta at both inner and outer distal angles, another on the dorsal surface near bases of
distal setae, and a short lateral seta.

Antennule (Fig. 9C) 18-segmented. Armature elements as follows: 1-1, II-l 1, III-2, IV-6,
V-2, VI-2, VII-2, VIII-2 + 1 aesthetasc, IX-2, X-2+ 1 aesthetasc, XI-2, XII-2, XIII-2+ 1
aesthetasc, XIV-1, XV-1, XVI-2, XVII-2 + 1 aesthetasc, XVIII-6+1 aesthetasc. Spinules
present on posterior surface of segment II.

Labrum (Fig. 12) large, posteriorly directed but not fused with rostrum; armed with 2 large
medially directed spinous processes on its posterior margin.

Antenna (Fig. 9D) basis lacking inner distal seta; endopod 3 -segmented, exopod
6-segmented. Endopod segment 1 with 2 inner distal setae; segment 2 with 3 setae spaced
along inner margin; segment 3 with 5 long distal margin setae. Exopod segment 1 unarmed;
segment 2 with 2 inner margin setae; segments 3 to 5 each with a single seta at inner distal
angle; segment 6 with 3 plumose setae.

Mandible (Fig. 9E) with well developed gnathobase bearing distally 4 multicusped blades,

114

G. A. BOXSHALL

Fig. 7 M. tetraspina. A, mandible, anterior; B, maxillule posterior; C, maxilla, anterior; D,

maxilliped, posterior. Scale 100 |im.

MISOPHRIOID COPEPODS

115

Fig. 8 M. tetraspina. A, leg 1 , anterior; B, leg 2, anterior; C, leg 3, anterior; D, leg 4, anterior; E,
leg 5, antero ventral. Scales 100 ^im unless otherwise stated.

116

G. A. BOXSHALL

Fig. 9 Misophriopsis dichotoma gen. et sp. nov. Holotype 9 A, dorsal view; B, urosome, ventral;
C, antennule, dorsal; D, antenna, anterior; E, mandible, posterior; F, detail of mandibular
gnathobase. Scales 100 (im unless otherwise stated.

MISOPHRIOID COPEPODS 117

several strong spines and a small subapical patch of pinnules. Mandibular palp comprising
basis, 2-segmented endopod and an indistinctly 5-segmented exopod. Basis armed with a
plumose seta midway along inner margin. Endopod segment 1 with plumose seta at inner
distal angle; segment 2 elongate with 4 unequal setae on distal margin. Exopod segments 1
and 2 incompletely separated; segment 1 unarmed; segments 2 and 3 each with a plumose
seta at inner distal angle; segment 4 probably with inner seta, missing from dissected appen-
dage but its presence indicated by a scar on the surface of the segment; segment 5 with 1 inner
and 2 distal margin setae.

Maxillule (Fig. 10 A), gnathobase with 7 distal margin spines, 2 hirsute setae and 3 naked
setae subapically on the posterior surface, and 2 plumose setae on a spinulate swelling on the
anterior surface. Endite 1 short and slightly furrowed on its posterior surface, armed with 6
apical plumose setae. Endite 2 long, with 3 apical plumose setae. Outer lobe rudimentary,
represented by 8 plumose setae on outer surface of segment. Maxillulary palp biramous with
2-segmented endopod and 1 -segmented exopod; segment 1 of endopod fused to basis, with
junction marked by 2 subapical setae. Endopod segment 1 with 4 plumose setae at inner
distal angle; segment 2 with 3 naked setae arising proximal to the midpoint of the inner
margin, 3 similar setae arising subapically on same margin, and 5 setae on distal margin.
Exopod with 9 plumose inner and distal margin setae of varying lengths and with fringes of
long pinnules proximally.

Maxilla (Fig. 1OB) 6-segmented; segment 1 with 5 plumose setae on proximal endite and 3
on distal endite; segment 2 with 3 plumose setae on both proximal and distal endites;
segment 3 produced medially into a curved claw armed with 2 naked setae near its base;
segments 4 to 6 with a total of 7 naked setae.

Maxilliped (Fig. IOC) 7-segmented, although proximal segment showing some signs of
subdivision at midlength. Segment 1 bearing 4 plumose setae and a short naked seta along
inner margin, and some long pinnules proximally on outer margin; segment 2 with 3 inner
margin plumose setae; segments 3 to 6 each with 2 long, unilaterally plumose setae at inner
distal angle; segment 7 with 3 distal setae.

Legs 1-4 (Figs 1 1 A-D) biramous, with 3-segmented rami. Armature formula as follows:

coxa basis endopod exopod

legl 0-1 I-I 0-1;0-2;1,2,3 I-1;I-1;III,I,4

Ieg2 0-1 1-0 0-1;0-2;1,2,3 I-1;I-1;III,I,5

leg 3 0-1 1-0 0-l;0-2;missing I-1;I-1;III,I,5

leg 4 0-1 1-0 0-l;0-2;missing I-1;I-1;III,I,5

Outer margins of all exopod segments with strips of serrated membrane. Rows of pinnules
present on inner margins of all exopod segments and inner and outer margins of endopod
segments. Outer margin spines of leg 1 armed bilaterally with fine strips of smooth
membrane. Apical spines with short pinnules along inner margins, and strip of smooth
membrane on outer margin in leg 1. Outer margin element on basis spinous on leg 1,
setiform on legs 2 to 4.

Leg 5 (Fig. 1 1 E) biramous, comprising unsegmented protopod, 2-segmented exopod and
1 -segmented endopod. Basal seta present at outer distal angle of protopod. Exopod segment
1 unarmed, segment 2 with 3 distal margin elements, a long plumose outer seta, a median
spine and an inner naked seta. Endopod with single plumose seta apically.

Leg 6 (Fig. 1 1 F) with transverse intercoxal sclerite joining members of leg pair reduced to a
slender bar. Leg comprising an outer process with a long apical seta, a median spine and an
inner spinous process.

MATERIAL EXAMINED. Holotype 9 collected at Discovery Stn 10379*37 (34°57 N 32°55' W)
in the North Atlantic to the southwest of the Azores. Caught in RMT1 +8M net system
fished 23 to 56 m off the bottom in a water depth of about 3000 m. BM(NH) Registration No.
1982-139.

118

G. A. BOXSHALL

Fig. 10 M. dichotoma. A, maxillule, posterior; B, maxilla, anterior; C, maxilliped, anterior.

Scales 100|im.

MISOPHRIOID COPEPODS

119

Fig. 11 M. dichotoma. A, leg 1 , anterior; B, leg 2, anterior; C, leg 3, anterior; D, leg 4, anterior; E,
leg 5, anteroventral; F, leg 6, ventral. Scales 1 00 ^im unless otherwise stated.

120

rostrum

G. A. BOXSHALL

antennule

antenna

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paragnath

intermaxillary
swelling

mandibular
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Fig. 12

M. dichotoma. Ventral view of mouthparts of left side, with antennule, left paragnath and
mandibular gnathobase removed. Scale 100 urn.

REMARKS. The new genus differs from all known misophrioids, and from all known
podopleans, in the possession of a biramous fifth leg. It also differs from other misophrioid
genera in the presence of a pair of large spinous processes on the posterior margin of the
labrum. The arrangement of the mouthparts (Fig. 12) is very similar to that of
Benthomisophria palliata. The antennae and mandibular palps are both reflexed so that their
setae will sweep over the areas of cone organs located laterally on the cephalosome as in
Benthomisophria.

Key to genera and species of the Misophrioida

1. Large anteriorly directed rostrum visible in dorsal view; antennule with 25 (rf) or 27 (9)

segments Archimisophria discovery!

Rostrum ventrally or postero ventral ly directed, not visible in dorsal view; antennule with
less than 25 segments 2

2. Leg 5 biramous, with 1 -segmented endopod and 2-segmented exopod ....

Misophriopsis dichotoma

Leg 5 uniramous, with 1 to 4 segments 3

3. Leg 5 4-segmented, antennule with 19 segments (9) . . . Misophriellatetraspina
Leg 5 with less than 4 segments, antennule with less than 1 9 segments (9) .... 4

4. Leg 5 3-segmented; antennule with 1 3 segments (d) or 1 6 segments (9) Misophria pallida
Leg 5 2-segmented, comprising a triangular proximal segment and short distal segment;

antennule with 18 (9) or 16 (d1) segments Benthomisophria palliata

Leg 5 1 -segmented; antennule with 16 segments (9 & rf) B.cornuta

MISOPHRIOIDCOPEPODS 121

Discussion

These three new genera exhibit between them an unusual array of plesiomorphic characters,
many of which are present in a state approaching that attributed to the hypothetical ancestor
of the Copepoda as a whole (see discussion in Boxshall et al., in press). The antennae, for
example, are biramous with an 8-segmented exopod and a 3-segmented endopod in
Archimisophria, and the mandibles have a well developed gnathobase plus a biramous palp
with a 5 -segmented exopod and 2 -segmented endopod in Misophriopsis. The basic structure
of both these limbs is the same as that proposed for the ancestral copepod. The detailed
structure of the maxillule was not considered in the discussion reported by Boxshall et al. (in
press) but in my opinion the misophrioid pattern of large gnathobase, 2 other endites, 1
setose outer lobe, a 1 -segmented exopod and a 3-segmented endopod, with the first segment
fused to the basis, may well be similar to that possessed by the ancestral copepod. The
misophrioid maxilla comprises 6 segments, the first 2 each bear a pair of setose endites, the
third a claw-like endite, and the fourth to sixth variable number of inner and distal setae.
This is close to what may be considered to be the ancestral copepod pattern. The
8-segmented maxilliped of Archimisophria consisting of a 3-segmented protopod and
5-segmented endopod is also very similar to the 9-segmented basic copepod maxilliped
favoured by Gurney (193 1) in his analysis of copepod appendages.

All these misophrioid features closely approximate to those exhibited by the
plesiomorphic calanoids. It is the common possession of these calanoid-like
gnathostomatous mouthparts and the possession of a heart that indicates that the
Misophrioida diverged from the podoplean lineage soon after its separation from the
gymnoplean lineage. The discovery of a 27-segmented antennule in Archimisophria and of a
biramous fifth leg in Misophriopsis clearly demonstrates that the Misophrioida has diverged
less from the common ancestral stock of the Copepoda than any other podoplean group.

The possession of a biramous fifth leg is of great phylogenetic significance. The difference
between the normal biramous fifth swimming leg of gymnopleans and the reduced
uniramous fifth leg of podopleans led Giesbrecht (1899) to suggest the possibility that they
are not homologous. Gurney (1931) rejected this and suggested that the typical uniramous
leg of podopleans represents the exopod of an originally biramous limb. This interpretation
has been widely adopted and the presence, in Misophriopsis, of a biramous fifth leg in which
the endopod is reduced to a single segment bearing a single seta provides further
confirmation. The fifth leg undergoes considerable reduction within the Misophrioida. In
Misophria the endopod is represented by a single median seta on the distal margin of the
unsegmented protopod, although the exopod is similar to that found in Archimisophria. In
Benthomisophria cornuta the fifth leg is reduced to a single segment.

The 27-segmented antennule of female Archimisophria is of interest because of the con-
siderable controversy that exists (see Boxshall et al, in press) concerning the nature of this
limb in the ancestral copepod. Giesbrecht (1892 & 1899) analysed the segmentation and
armature of the antennules of many calanoid and other copepods in an attempt to reduce the
antennule of all copepods to a common type. Giesbrecht's basic copepod antennule was
25-segmented and by studying the arrangement of the armature elements he was able to
determine which segments had fused in those forms with fewer segments. This basic limb
closely resembles that ofCalanusfinmarchicusGunnerus, 1770 both in number of segments
and in setation. The typical armature present on each antennulary segment is 2 setae and 1
aesthetasc, at least in the female, although one or more of these elements is often lost, most
commonly the aesthetasc. Even the arrangement of these 3 elements, which Giesbrecht
called a 'trithek', follows a constant pattern. One seta, the proximal seta, is positioned about
midway along the anterior margin of the segment whereas the other seta, the distal seta, and
the aesthetasc are positioned close together at the distal angle of the anterior margin. The
typical trithek may have been different for the male, because a proximal and a distal seta
plus 2 distal aesthetascs are commonly found, as for example, in Eucalanus attenuatus
Dana, 1849. Some of the more distal segments have modified tritheks. In female Calanus

122

G. A. BOXSHALL

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MISOPHRIOID COPEPODS 123

finmarchicus segments 20 and 21 have no proximal seta, segments 22, 23 and 24 have no
proximal seta but have instead a distal seta on the posterior margin, and the terminal
segment 25 has an increased armature of up to 6 setae and an aesthetasc (see Table 1). As
Gurney (193 1) noted, many calanoids possess 3 complete tritheks on the second segment and
a single proximal seta plus a distal trithek on the first segment. He interpreted this as
evidence that the second segment of calanoid antennules is derived from 3 fused segments
and that the first segment may be derived from 2 fused segments. On the basis of this
interpretation he postulated that the ancestral copepod antennule comprised 27 or possibly
28 segments. The discovery of Archimisophria with its 27-segmented antennules provides a
remarkable corroboration of Gurney 's hypothesis.

Comparison between the antennules of female Calanus finmarchicus and Archimisophria
discoveryi is made in Table 1. The precise correspondence in the position of typical tritheks,
denoted by T or t, and of modified tritheks, denoted by D or d and P or p, in these two taxa is
remarkable as they are drawn from the 2 main copepod lineages, Gymnoplea and Podoplea.
It is possible from the comparison in Table 1 to identify a common pattern from which both
may be derived by reduction. I suggest that this pattern may well represent that found in the
common ancestor of the Copepoda.

Functional interpretation of the unique characters exhibited by misophrioids (Boxshall,
1982 & in press) suggests that the ancestral misophrioid stock became adapted to a
bathypelagic existence and to gorging as a feeding strategy. The group appears to have
radiated in the deep-sea near-bottom environment and it is probable that many new
misophrioid taxa will be discovered as the near-bottom community is subject to more
intense study. Despite their obvious specializations the misophrioids also retain many
characters of the presumed ancestral copepod stock and it is clear that they diverged from the
ancestral podoplean stock soon after it had attained its characteristic division into prosome
and urosome.

Acknowledgements

I would like to thank P. M. David and Dr Howard Roe of the Institute of Oceanographic
Sciences for permission to work on this material and for arranging for it to be donated to the
BM(NH) collections. I am also grateful to Dr Roger Lincoln for reading and commenting on
the manuscript.

References

Boeck, A. 1864. Oversigt over de ved Norgs Kyster iagttagne Copepoder henhevende tie Calanidernes,

Cyclopidernes og Harpacticidernes Familiar. Fork. VidenskSelsk. Krist. 1864 : 226-28 1 .
Boxshall, G. A. 1982. On the anatomy of the misophrioid copepods, with special reference to

Benthomisophria palliata Sars. Phil. Trans. R. Soc. Lond. B. 297 : 125-181.
in press. The functional morphology of Benthomisophria palliata Sars, with a consideration of

the evolution of the Misophrioida. Crustaceana, Suppl. in press.
Boxshall, G. A., F. D. Ferrari & H. Tiemann. in press. The ancestral copepod: towards a consensus of

opinion at the First International Conference on Copepoda. Crustaceana, Suppl. in press.
Boxshall, G. A. & H. S. J. Roe. 1980. The life history and ecology of the aberrant bathypelagic genus

Benthomisophria Sars, 1909 (Copepoda: Misophrioida). Bull. Br. Mus. nat. Hist. (Zool.)38 : 9-41.
Dana, J. D. 1849. Conspectus Crustaceorum quae in orbis terrarum circumnavigatione, Carolo

Wilkes e classe Reipublicae Foederatae duce, lexit et descripsit Jacobus D. Dana. Proc. Am. Acad.

ArtsSci.2: 8-61.
Giesbrecht, W. 1892. Systematik und Faunistik des pelagischen Copepoden des Golfes von Neapel

und der angrenzenden Meeresabschnitte. Fauna Flora Golfo Napoli 19: 1-83 1 .
1899. Die Asterocheriden des Golfes von Neapel und der angrenzenden Meeresabschnitte. Fauna

Flora Golfo Napoli 25 : 1-2 1 7.
Gunnerus, J. E. 1770. Nogle smaa rare mestendelen nye norske S0dyr beskrevene. Skr.

Kiobenhavnske Selsk. Laerd. og Videnskab. Elsk. 10 : 175.

124 G. A. BOXSHALL

(in nicy, R. 1931. British Fresh-water Copepoda Vol. 1 . Ray Society, Lond.

Hulsemann, K. & Grice, G. D. 1964. A new bathypelagic species of Benthomisophria (Copepoda:

Misophriidae) from the North Atlantic. Zoo/. Anz. 173 : 259-264.
Sars, G. O. 1909. Note preliminaire sur trois formes remarquables de copepodes provenant des

Campagnes de S.A.S. Le Prince Albert de Monaco. Bull. Inst. Oceanogr. Monaco. 147 : 1-8.

Manuscript accepted for publication 9 June 1 982

Larval development of British prawns and shrimps
(Crustacea: Decapoda: Natantia) 4. Palaemon
(Palaemon) serratus (Pennant, 1777) and
functional morphology of swimming

A. A. Fincham

Department of Zoology, British Museum (Natural History), Cromwell Road, London
SW7 5BD

Introduction

Palaemonid shrimps are widely distributed in the N.E. Atlantic being found in fresh water,
in estuaries, intertidally and down to 40 m offshore, but their larvae are rare in the plankton.
All decapod larvae have a natural tendency to sink (Foxon, 1934) and in order to maintain
position at a particular depth (Savage, 1926) and perform daily vertical migrations (Russell,
1925, 1927; Hardy & Bainbridge, 1954), active upward swimming is necessary also. Foxon
measured rates of movement in various decapods including pandalid carideans and several
authors have noted the effect of light and gravity on the orientation and movement of
decapod larvae (Sollaud, 1921;Gurney, 1942; Forward &Cron in, 1978).

The aim of this paper is to review the larval development of Palaemon (Palaemon)
serratus (Pennant, 1777) and report on morphological adaptations, and a mechanism using
many-jointed plumose setae fringing the thoracic exopods, for larval swimming.

Materials and Methods
Rearing

Ovigerous Palaemon (Palaemon) serratus were trawled from 12 m in April 1979 from
Plymouth Sound, Devon (Grid reference: SX 475512). Similar rearing techniques to those
reported previously (Fincham 1977, 1978, 1979) were used with the following modifications:

1 . The controlled temperature room was at 1 4 °C.

2. Antibiotics were used for the first three stages only (Fincham, 1979).

Larval material has been deposited in the Crustacea collection of the BM(NH), registration
number 1982 : 186.

Telson morphology

The telson was removed from larvae by a cut at the narrow junction with the abdomen,
rinsed in distilled water, freeze dried, mounted end-on with Araldite on stubs, coated with
gold and examined with a scanning electron microscope.

Palaemon (Palaemon) serratus (Pennant, 1 777)

Astacus serratus Pennant, 1777

Melicerta triliana Risso, 1816

Palaemon trilianus Risso, 1826

Palaemon treillianus H. Milne Edwards, 1837

Leander latrei/lianus Czerniavsky, 1 884

Bull. Br. Mus. not. Hist. (Zool.)44(2): 125-161 Issued 24 February 1983

125

126

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128 A. A. FINCHAM

Leander serratus Sharp, 1 893
Leander treillianus Adensamer, 1 898
Leander serratus var. treillianus De Man, 1915
Palaemon (Palaemon) serratus Holthuis, 1950

SYNOPSIS OF LARVAL DATA FROM PUBLISHED WORK. Thompson, 1 836 zoeae I, III & V, p. 22 1 ,
Figs 1-5, laboratory reared and plankton. Couch, 1845 zoea I, p. 20, no Figs, laboratory
reared. Mayer, 1877 zoea I, telson, p. 250, Fig. 49. Keeble and Gamble, 1904 zoea I,
chromatophores, p. 316. Sollaud, 1912 zoeae I-IX, p. 664, no Figs, laboratory reared.
Williamson, 1915 zoea II (not I), Figs 120-125, zoea I Figs 126-128, last zoea Figs 129-132,
p. 396, plankton. Sollaud, 1923 zoeae I-IX & post larva I, p. 530, plates 16-18 (Figs 1^
only), laboratory reared and plankton. Reeve, 1969 zoeae I-V (XI), p. 77, no Figs,
laboratory reared. Sutton et at., 1969 zoea I, counting larvae, p. 433, Fig. 1, laboratory
reared. Fincham & Williamson, 1978 key to larval stages.

In the following short descriptions of the key characters of the larval stages, setal counts
have been omitted usually, but they are recorded in Table 1 .

Description of larval stages

Key characters are printed in italic type and are useful for separating stages in British species.
ZOEA 1 (Fig. 1)3-3 mm (3-2-3-5 mm)

Head (Figs la, b): eyes sessile.

Carapace (Figs la, b): without spines, rostrum straight or downcurved at tip, tapering

distally, ventral margin with minute retrorse teeth distally, equal to, or greater than, length of

peduncle of antenna 1 but not reaching to end of antenna I (excluding terminal aesthetascs

and setae).

Antenna 1 (Fig. Ic): peduncle bearing single flagellar segment with three aesthetascs distally,

usually two narrow and one wide, occasionally 1 narrow and 2 wide.

Antenna 2 (Fig. Id): exopodite as a broad lamina divided into 5 short segments distally, with

9 + 2 plumose setae on inner and distal margins. Endopodite of one segment (0-67 length of

exopodite), with terminal plumose seta and short spine.

Mandibles (Fig. le): asymmetrical.

Maxillipeds 1-3 (Figs Ih-j): with natatory exopodites.

Pereiopods 1,2 (Figs Ik, 1): rudimentary, biramous.

Pereiopods 3-5: absent.

Abdomen (Figs 1 a, b): somite 5 with posterior margin rounded, not produced into spines,

somite six continuous with telson. No trace of pleopods.

Telson (Fig. Ip): fans out distally, posterior margin bears 7 + 7 plumose spines, with minute

spines between four innermost spines.

ZOEA 2 (Fig. 2) 3-7 mm (3-5-3-9 mm)

Head (Figs 2a, b): eyes stalked.

Carapace (Figs 2a, b): one dorso-medial and a pair of supra-orbital spines all bent forward

with small retrorse teeth, rostrum without teeth, downturnedat end to form small hook.

Antenna 1 (Fig. 2c): two peduncle segments, stylocerite forming on proximal external margin

of first segment; single flagellar segment with four terminal aesthetascs, two wide and two

narrow.

Antenna 2 (Fig. 2d): exopodite with 4 or 5 short segments distally.

Pereiopods 1 , 2 (Figs 2k, 1): developed with natatory exopodite.

Pereiopods 3, 4 (Figs 2m, n): rudimentary, biramous.

Pereiopod 5 (Fig. 2o): rudimentary, uniramous.

Abdomen (Figs 2a, b): somite 5 with posterior margin produced into a pair of conspicuous

spines, somite 6 continuous with telson.

Telson (Fig. 2p): developing uropods visible beneath exoskeleton alongside telson proper; in

central group of small spines, one pair longer than others.

LARVAL DEVELOPMENT OF P. (P.)SERRATUS

129

Fig. 1 Zoea 1: (a) dorsal view; (b) lateral view; (c) antenna 1; (d) antenna 2; (e) mandibles; (f)
maxilla 1; (g) maxilla 2; (h) maxilliped 1; (i) maxilliped 2; (j) maxilliped 3; (k) pereiopod 1; (1)
pereiopod 2; (m) telson. Bar scales: a, b = 0-5 mm; c, d, h-m = 0-2 mm; g, f= 0-1 mm; e = 0-05
mm.

130

A. A. FINCHAM

Fig. 2 Zoea 2: (a) dorsal view; (b) lateral view; (c) antenna 1; (d) antenna 2; (e) mandibles; (0
maxilla 1; (g) maxilla 2; (h) maxilliped 1; (i) maxilliped 2; (j) maxilliped 3; (k) pereiopod 1; (1)
pereiopod 2; (m) pereiopod 3; (n) pereiopod 4; (o) pereiopod 5; (p) telson. Bar scales: a, b = 0-5
mm;c, d, h-p = 0-2 mm;g, f=0-l mm;e = 0-05 mm.

LARVAL DEVELOPMENT OF P. (P.)SERRATUS

131

Fig. 3 Zoea 3: (a) dorsal view; (b) lateral view; (c) mandibles; (d) maxilla 1; (e) maxilla 2. Bar
scales: a,b = 0-5 mm; c = 0-05 mm; d, e = 0-l mm.

ZOEA 3 (Figs 3,4) 4-0 mm (3-7-4-3 mm)

Carapace (Fig. 3a, b): two dorso- medial spines and a small fronto-lateral spine at edge of

carapace beneath the eyes, former with retrorse teeth ventrally.

Antenna 1 (Fig. 4a): conspicuous spine medially, stylocerite more pronounced; distal

segment of peduncle bearing first segment of internal flagellum, single segment of external

flagellum bearing 3 wide aesthetascs distally.

Antenna 2 (Fig. 4b, c): exopodite with distal part divided into 3 short segments; endopodite of

3 segments.

132

A. A. FINCHAM

Fig. 4 Zoea 3: (a) antenna 1 ; (b) antenna 2; (c) distal part of exopodite of antenna 2; (d) maxilliped
1; (e) maxilliped 2; (0 maxilliped 3; (g) pereiopod 1; (h) pereiopod 2; (i) pereiopod 3; (j)
pereiopod 4 ;(k) pereiopod 5;(l)telson. Bar scales: a, b, d-I=0-2 mm; c = 0-05 mm.

LARVAL DEVELOPMENT OF P. (P.) SERRA TVS 1 33

Abdomen (Figs 3a, b, 41): somite 6 divided from telson by suture. Uropod endopodite

rudimentary with no marginal setae, exopodite with marginal setae.

Telson (Fig. 41): narrower but still broader distally, outer pair of spines on posterior margin

reduced.

ZOEA 4 (Figs 5, 6) 4-5 mm (4-1-5-0 mm)

Carapace (Fig. 5a, b; Fig. 6a, b): three dorso- medial spines with retrorse teeth ventrally; pair

of small fronto-lateral spines at edge of carapace beneath the eyes; rostrum still

downturned at end to form a small hook.

Antenna 1 (Fig. 5c): single segment of external flagellum bearing 3 wide and 1 narrow

aesthetascs distally.

Antenna 2 (Fig. 5d): distal part of exopodite no longer divided into segments.

Pereiopod 3 (Fig. 6h): developed with natatory exopodite.

Pereiopod 4 (Fig. 6i): rudimentary, biramous.

Pereiopod 5 (Fig. 6j): developed, uniramous.

Abdomen (Figs 5a, b): endopodite and exopodite of uropod both with marginal plumose

setae.

Telson (Fig 6k): narrower but still broader distally; posterior margin weakly concave with

4 + 4 large spines, the 3 outer spines on the latero-distal margin reduced (outer pair

sometimes absent).

ZOEA 5 (Figs 7-9) 5-5 mm (5-2-5-8 mm)

Carapace (Figs 7a, b): rostrum still downturned to form a small hook.

Antenna 1 (Fig. 8a): rudiment of 'circular statocyst visible on first segment of peduncle.

Antenna 2 (Fig. 8b): endopodite of 3 or 4 segments.

Pereiopods 1 , 2 (Figs 9a, b): endopodite with internal distal margin of propodus produced

slightly forward (will become fixed finger of chela).

Pereiopod 4 (Fig. 9d): developed, exopod with rudimentary fringing setae.

Telson (Fig. 9f): a little broader distally than proximally; spine formula as in Zoea 4 but with

further reduction or even loss of small outer spines.

Abdomen (Fig. 7b): somites 1-5 with rudimentary pleopods.

ZOEA 6 (Figs 10-12) 5-7 mm (5-2-7-4 mm)

Carapace (Figs lOa, b): rostrum weakly hooked at tip; short plumose seta in angle of anterior
dor so- medial spine.

Antenna 1 (Fig. 11 a): single external flagellum with four aesthetascs distally, additional
group of 2 or 3 narrow aesthetascs on internal margin.

Antenna 2 (Fig. lib): increase in number of segments of endopodite flagellum,
approximately equal to scaphocerite in length, small spine on distal margin of peduncle
segment.

Maxilla 2 (Fig. 1 le): occasional increase in number of setae on basis 1 .
Maxilliped 1 (Fig. 1 If): one plumose seta on proximo-lateral margin of exopod.
Pereiopods 1, 2 (Figs 12a, b): endopodite with internal distal margin of propodus produced
foreward to almost half length ofdactylus (excluding terminal setae).
Pereiopod 4 (Fig 12d): exopodite occasionally with fringing plumose setae reduced.
Abdomen (Fig. lOb): pleopods on somites 1-5 rudimentary, biramous.

ZOEA 7 (Figs 13-15)6-1 mm (5-5-6-7 mm)

Carapace (Figs 1 3a, b): rostrum straight or weakly hooked at tip; 2 or 3 short plumose setae in

angle of anterior dorso- medial spine.

Antenna 1 (Fig. 14a): two or occasionally three groups of aesthetascs on internal margin of

external flagellum.

Maxilla 2 (Fig. 14e): up to 6 setae on basis 2.

Maxilliped 1 (Fig. 14f): 2-5 plumose setae on proximo-lateral margin of exopodite.

Pereiopods 1, 2 (Figs 15 a, b): endopodite with internal distal margin produced forward to half

length ofdactylus (excluding terminal setae).

134

A. A. FINCHAM

Fig. 5 Zoea 4: (a) dorsal view; (b) lateral view; (c) antenna 1; (d) antenna 2; (e) mandibles; (0
maxilla l;(g) maxilla 2. Bar scales: a, b = 0-5 mm;c, d = 0-2 mm;e = 0-05 mm; f, g = 0-l mm.

LARVAL DEVELOPMENT OF P. (PJSERRATUS

135

Fig. 6 Zoea 4: (a) tip of rostrum; (b) fronto-lateral corner of carapace; (c) maxilliped 1; (d)
maxilliped 2; (e) maxilliped 3; (f) pereiopod 1; (g) pereiopod 2; (h) pereiopod 3; (i) pereiopod 4;
(j)pereiopod 5;(k)telson. Bar scales: a, b = 0-05 mm;c-k = 0-2 mm.

136

A. A. FINCHAM

Fig. 7 Zoea 5: (a) dorsal view; (b) lateral view. Bar scales: 0-5 mm.

LARVAL DEVELOPMENT OF P. (P.) SERRA TVS

137

Fig. 8 Zoea 5: (a) antenna 1; (b) antenna 2; (c) mandibles; (d) maxilla 1; (e) maxilla 2; (f)
maxilliped 1 ; (g) maxilliped 2; (h) maxilliped 3. Bar scales: a, b, f-h = 0-2 mm; c = 0-05 mm; d,
e = 0-l mm.

138

A. A. FINCHAM

Fig. 9 Zoea 5: (a) pereiopod 1 ; (b) pereiopod 2; (c) pereiopod 3; (d) pereiopod 4; (e) pereiopod 5;

(f) telson. Bar scale: 0-2 mm.

LARVAL DEVELOPMENT OF P. (P.)SERRATUS

139

Fig. 10 Zoea 6: (a) dorsal view; (b) lateral view. Bar scales: 0-5 mm.

140

A. A. FINCHAM

Fig. 11 Zoea 6: (a) antenna 1; (b) antenna 2; (c) mandibles; (d) maxilla 1; (e) maxilla 2; (0
maxilliped 1; (g) maxilliped 2; (h) maxilliped 3. Bar scales: a, b, f-h = 0-2 mm; c=0-05 mm; d,
e = 0-l mm.

Pereiopod 4 (Figs 1 5d, e): exopodite occasionally with fringing plumose setae much reduced.
Abdomen (Figs 13b, 15g-k): pleopods 1-5 still rudimentary, biramous with traces of
terminal setae on exopodites.
Telson (Figs 1 3a, 1 5 1 ): posterior margin straight or slightly convex.

LARVAL DEVELOPMENT OF P. (P.)SERRATUS

141

Fig. 12 Zoea 6: (a) pereiopod 1 ; (b) pereiopod 2; (c) pereiopod 3; (d) pereiopod 4; (e) pereiopod 5;

(Otelson. Bar scale: 0-2 mm.

ZOEA 8 (Figs 16-1 9) 6-6 mm (5-8-7-1 mm)

Maxilliped 1 (Fig. 1 8a): up to 6 plumose setae on proximo- lateral margin ofexopodite.

Pereiopod 1 , 2 (Figs 1 8d, e): endopodite with internal distal margin produced forward to over

half length ofdactylus (excluding terminal setae).

Telson (Fig. 1 9i): posterior margin convex.

142

A. A. FINCHAM

Fig. 13 Zoea 7: (a) dorsal view; (b) lateral view. Bar scales: 0-5 mm.

ZOEA 9 (Figs 20-23) 7-3 mm (6-9-7-9 mm)

Carapace (Fig. 20b): 3 short plumose setae in angle of anterior dorso- medial spine, 1 in angle

of second dor so- medial spine.

Antenna 1 (Fig. 2 la): internal flagellum of 1 or 2 segments, external flagellum of 2 segments;

3 or 4 groups of aesthetascs on internal margin of external flagellum; statocyst fully

developed.

Antenna 2 (Fig. 21b): increase in number of segments of endopodite flagellum, now longer

than scathocerite.

Maxilliped 1 (Fig. 21g): 14 to 20 setae on internal margin of basis, 5 to 9 plumose setae on

proximo- lateral margin ofexopodite.

LARVAL DEVELOPMENT OF P. (P.) SERRA TVS

143

Fig. 14 Zoea 7: (a) antenna 1; (b) antenna 2; (c) mandibles; (d) maxilla 1; (e) maxilla 2; (0
maxilliped 1; (g) maxilliped 2; (h) maxilliped 3. Bar scales: a, b, f-h = 0-2 mm; c=0-05 mm; d,
e = 0-l mm.

144

A. A. FINCHAM

Fig. 15 Zoea 7: (a) pereiopod 1 ; (b) pereiopod 2; (c) pereiopod 3; (d) pereiopod 4; (e) variant of
pereiopod 4 exopod with reduced setae; (0 pereiopod 5; (g) pleopod 1 ; (h) pleopod 2; (i) pleopod
3; (j) pleopod 4; (k) pleopod 5; (1) telson. Bar scale = 0-2 mm.

LARVAL DEVELOPMENT OF P. (P.)SERRATUS

145

Fig. 16 Zoea 8: (a) dorsal view; (b) lateral view. Bar scales: 0-5 mm.

146

A. A. FINCHAM

Fig. 17 Zoea 8: (a) mandibles; (b) maxilla 1; (c) maxilla 2; (d) antenna 1; (e) antenna
1 - enlargement of proximal array of sensory hairs showing thread-like connections remaining in
cast exoskeleton; (0 antenna 2. Bar scales: a, e = 0-05 mm; b, c = 0- 1 mm; d, f = 0-2 mm.

LARVAL DEVELOPMENT OF P. (P.) SERRA TUS

147

Fig. 18 Zoea 8: (a) maxilliped 1 ; (b) maxilliped 2; (c) maxilliped 3; (d) pereiopod 1 ; (e) pereiopod

2. Bar scale: 0-2 mm.

148

A. A. FINCHAM

Fig. 19 Zoea 8: (a) pereiopod 3; (b) pereiopod 4; (c) pereiopod 5; (d) pleopod 1 ; (e) pleopod 2; (0
pleopod 3; (g) pleopod 4; (h) pleopod 5; (i) telson. Bar scale: 0-2 mm.

LARVAL DEVELOPMENT OF P. (P.) SERRA TVS

149

Fig. 20 Zoea 9: (a) dorsal view; (b) lateral view. Bar scales: 0-5 mm.

Pereiopods 1, 2 (Figs 22c, d): endopodite with immovable finger of propodus produced

forward to almost length ofdactylus (excluding terminal setae)

Abdomen (Figs 20b, 23c-g): pleopods with rudimentary setae, a few fully plumose;

endopodite of pleopods 2 to 5 with rudiment of appendix interna (stylamblys).

Telson (Fig. 23h): further narrowing distally, posterior margin with 4 + 4 large spines (no

small spines between) and with 3 reduced spines on latero-distal margin.

150

A. A. FINCHAM

Fig. 21 Zoea 9: (a) antenna 1 ; (b) antenna 2; (c) antero-lateral teeth of carapace; (d) mandibles; (e)
maxilla l;(f) maxilla 2; (g) maxilliped 1. Bar scales: a, b, g = 0-2 mm; c, d = 0-05 mm; e, f=0-l
mm.

LARVAL DEVELOPMENT OF P. (P.) SERRATUS

151

Fig. 22 Zoea 9: (a) maxilliped 2; (b) maxilliped 3; (c) pereiopod 1; (d) pereiopod 2; (e) pereiopod

3. Barscale = 0-2 mm.

152

A. A. FINCHAM

Fig. 23 Zoea 9: (a) pereiopod 4; (b) pereiopod 5; (c) pleopod 1; (d) pleopod 2; (e) pleopod 3; (0
pleopod 4; (g) pleopod 5; (h) telson. Bar scale: 0-2 mm.

LARVAL DEVELOPMENT OF P. (P.)SERRATUS

153

Fig. 24 Post larva 1: (a) rostrum; (b) rostrum with characters intermediate between larval and
post larval phases; (c) antenna 1; (d) antenna 2; (e) mandible; (0 maxilla 1; (g) maxilla 2. Bar
scales: a, b = 0-5 mm;c, d = 0-2 mm; e = 0-05 mm; f, g = 0-l mm.

154

A. A. FINCHAM

Fig. 25 Post larva 1 : (a) maxilliped 1 ; (b) maxilliped 2; (c) maxilliped 3; (d) pereiopod 1 chela; (e)
pereiopod 2 chela; (0 pereiopod 3; (g) pereiopod 4; (h) pereiopod 5. Bar scale: 0-2 mm.

POST LARVA 1 (Figs 24-26) 7-9 mm (7-0-8-6 mm)

Most specimens had metamorphosed to post larvae or intermediate stages at this
moult. Meristic characters of the more advanced individuals are described here and included
in Table 1.

LARVAL DEVELOPMENT OF P. (P.)SERRATUS

155

Fig. 26 Post larva: (a) pleopod 1; (b) pleopod 2; (c) pleopod 3; (d) pleopod 4; (e) pleopod 5; (0
somite 5 with postero-lateral spines (plumose setae of pleopod 5 not shown); (g) uropod
exopodite (plumose setae not shown); (h) telson. Bar scale: 0-2 mm.

Fig. 27 Telson of palaemonid Zoea 1 . (a) Dorsal view of posterior margin. Bases of large plumose
spines with row of smaller spines between, (b) Single large spine ornamented with spinules. (c)
Articulation at base of large spines with circlet of small spines, (d) Ventral view of posterior
margin showing rows of small spines arranged with gaps.

LARVAL DEVELOPMENT OF P. (P.)SERRATUS

157

Fig. 28 Single plumose seta from natatory exopodite of pereiopod. Shaft is a differentially
thickened cylinder hinged at intervals and bears two rows of thin lateral setules. (a) Seta
stationary, (b) Beginning of recovery stroke, (c) End of recovery stroke. Bar scale: 0-05 mm.

Carapace (Fig 24a): rostrum with 6 or 7 dorsal and 2 ventral teeth, rostral tip straight.

Supra- orbital spines missing. Intermediate condition of rostrum shown in Fig. 24b.

Antenna 1 (Fig. 24c): internal Jlagellum of 5 or more segments and external Jlagellum of 6 or

more segments.

Antenna 2 (Fig. 24d): endopodite multisegmented, at least twice as long as scaphocerite.

Mandible (Fig. 24e); divided into pars incisiva and pars molaris, lacinia mobilis no longer

present and palp (three jointed in adult) not yet appeared.

Maxilla 2 (Fig. 240: reduction of setae on coxal endite and endopodite, increase in setae on

basal endites.

Maxilliped 2 (Fig. 25b): endopodite with dactylus, propodus and merus flattened.

Maxilliped 3 (Fig. 25c): endopodite dactylus shortened.

Pereiopods 1 , 2 (Figs 25d, e): immovable finger of propodus same length as dactylus.

Pereiopods 3, 4 (Figs 25f, g): dactylus shortened.

Pleopod 1 (Fig. 26a): ratio of endopodite to exopodite 1:4; endopodite bearing terminal

plumose setae, exopodite fringed with long plumose setae.

Pleopods 2-5 (Figs 26b-e): endopodite over half length of exopodite, both with long,

marginal plumose setae, endopodite with appendix interna bearing well developed intero-

distal coupling hooks.

Abdomen (Fig. 260: fifth abdominal somite with posterior margin still produced into pair of

lateral spines.

158 A. A. FINCHAM

Telson (Fig. 26g): intermediate condition (extreme narrowing with posterior margin
tapering to point not yet developed).

Discussion

Most of the specimens reared by Sollaud (1912) at the Marine Laboratory in Roscoff reached
metamorphosis after 8 larval stages. But he found also '. . . quelques individus, en effet,
peuvent presenter un stade IX supplementaire avant de se transformer. . .' He concluded,
however, that the normal larval development for Palaemon serratus was eight stages
(Sollaud, 1923). In the present work the differences between stages 8 and 9 were slight and
confirm, therefore, the conclusion reached by Sollaud. The insertion of extra moults which
probably represents an adaptation to sub-optimal conditions by prolonging larval existence
is a recurrent feature of the development of Palaemoninae (Fincham, 1977, 1979). Sandifer
and Smith (1979) indicated that in addition to being affected by environmental factors the
tendency of individual palaemonid larvae to pass through a given number of larval stages
may be inherited. They suggested also that variation in development may enhance the
general advantages of an extended planktonic larval phase, a common feature of 'r'
strategists. These include greater potential for dispersion and the ability to colonize new
habitats quickly if favourable conditions occur. A variable planktonic existence may
produce a wider spread of individuals of a given brood and average the risks of survival. At
the population level Sandifer and Smith emphasize that early metamorphosis will enhance
the possibility of gene flow between populations.

Many environmental factors affect development including photoperiodicity. Wickins
(1972) reported work on larval Palaemon serratus in which growth was improved and
metamorphosis reached sooner in those reared in continuous light. Eight hours dark and 16
hours light produced improved growth compared with 8 hours light and 16 hours dark;
continuous darkness produced slowest growth and development. Dalley (1979) working with
Palaemon elegans concluded that greatly increased mortality during larval development in
non-circadian light regimes was due to desynchronization of the circadian rhythms of
metabolic processes.

One feature commonly found in exuviae of the various larval stages are thin strands
extending from the bases of sensory hairs (see Figs 17d, e). In a paper on the ultrastructure of
the antennal sensilla of the shrimp Acetes Ball & Cowan (1977) describe dense strands of
unknown composition crossing the base of their type 1 seta, which they consider
uninnervated. Tracts leading from the bases of their other four types of seta contain axons.
The exact nature of the strands in the exuviae of Palaemon serratus is not clear and will be
examined further.

Swimming: adaptations and a mechanism

When palaemonid larvae first hatch they usually swim upside down and telson first. At rest
the larvae tend to sink and there are several adaptations which slow the rate of descent. At
either end of the body plumose setae or spines increase drag. Fringing plumose setae
effectively double the area of the broad exopodite (scaphocerite) of antenna 2 at the anterior
end of the body (Figs la, 2a, 3a, 5a, 7a, lOa, 13a, 16a, 20a). These antennal setae are
thickened at the base (Fig. 4c) and their rigidity increases drag when the exopodites are
spread.

At the posterior end the telson bears stout spines which are ornamented with rows of small
spines and are also plumose (Figs 27a-d). The function of the ornamentation is uncertain but
might further slow the rate of sinking. Body size increases as larval development progresses
and the importance of even the large spines on the telson for increasing drag, diminishes
when the sixth abdominal segment develops its appendages. The exopodites of these uropods

LARVAL DEVELOPMENT OF P. (P.) SERRA TVS \ 59

appear at zoea 3 (Fig. 41) and endopodites at zoea 4 (Fig. 6k) and are broad and flat and
fringed with plumose setae. The spreading of these uropods slows the rate of sinking during
periods when the larva is not swimming.

The telson, however, retains its important function as a stabilizing hydrofoil throughout
larval life and is supplied with powerful muscles that enable it to assist in orientation control.
Its gradual transformation from a triangular shape at zoea 1 with a 7 + 7 spine formula (Figs
1m, 27a-d) to the narrow shape at the last larval stage with spine formula 4 + 4 and three
pairs of lateral spines (Fig. 23h) accompanies the gradual development of more thoracic
natatory exopodites.

In the present rearing programme food is supplied to the larvae in the form of Anemia
nauplii. In the wild it is likely that copepods and other small planktonic organisms form the
main source of food (Sollaud used copepods in his rearing work at Roscoff). The pursuit of
prey- Anemia or copepods - necessitates accurate orientation and direction control. The
propulsive locomotory force is provided by the natatory exopodites developed sequentially.
Zoea 1 has only three natatory exopodites - those of the maxillipeds-but biramous
pereiopods are developed later and are also integrated into a regular beating pattern of the
limbs. Pereiopod 5 is in fact developed by stage 4 before pereiopod 4 in Palaemon serratus
but has no exopodite and is therefore not involved in larval swimming. The effective area of
the propulsive exopodites is extended by the fringing plumose setae. Preliminary analysis of
the swimming action from cine film shows that there is a power stroke and a recovery stroke.
The morphological adaptations of these plumose setae and their role in swimming behaviour
was determined following the routine examination by light microscopy of hundreds of
moults during the course of the rearing programme.

The shaft of the plumose setae fringing the natatory exopodites is a differentially thickened
cylinder with flexible cuticular hinges at intervals along its length (Fig. 28a). The hinges only
permit bending towards the unthickened side of the shaft. During the propulsive power
stroke the setae remain straight with the two rows of thin, lateral setules set at an obtuse angle
to the shaft, thus providing maximum surface area and purchase in the water. On the
recovery stroke the flexible exopodite bends and the marginal plumose setae fold back along
the many hinge lines with their thin side branches streaming out behind. This offers the least
possible resistance by the exopodite to the water and repositions the limb ready to begin the
next power stroke.

The rhythmic beating of the six pairs of setose thoracic exopodites in the three larval
stages, and swimmerets or pleopods in the post larvae of lobsters, has been analysed from
cine film by Neil et al. (1976), Macmillan et al. (1976) and Laverack et al. (1976). No
comparable study has been made for a caridean with regular sequential addition of limbs (in
lobsters all limbs are present on hatching). The rarity of palaemonid larvae in the plankton
remains an enigma especially as they are apparently so well adapted for swimming. Detailed
analyses of cine film of swimming in larval palaemonids, together with plankton sampling
using a static bottom net and experimental work on the periodicity of larval swimming, all of
which are in progress, should shed some light on the problem.

References

Adensamer, T. 1898. Decapoden gesammelt auf S.M. Schiff Pola in den Jahren 1890-1894. Berichte

der Commission fur Erforschung des ostlichen Mittelmeeres. XXII Zoologische Ergebnisse. XI.

Denkschr. Akad. Wiss. Wien6S : 597-628.
Ball, E. E. & Cowan, A. N. 1977. Ultrastructure of the antennal sensilla of Acetes (Crustacea,

Decapoda, Natantia, Sergestidae). Phil Trans. R. Soc. Lond. B 277 : 429-456.
Couch, R. Q. 1845. On the metamorphosis of the crustaceans, including the Decapoda, Entomostraca

and Pycnogonidae. Rep. R. Cornwall polytech. Soc. 12 : 17-46.
Czerniavsky, W. 1884. Crustacea Decapoda Pontica littoralia, Materialia ad Zoographiam Ponticam

comparatum. II. Trans. Soc. Univ. Kharkow, 13 (suppl.) : 1-268.

160 A. A. FINCHAM

Dalley, R. 1979. Effects of non-circadian light cycles on the survival and development of Palaemon

elegans Rathke reared in the laboratory. In: Proc. 13th Eur. mar. Biol. Sym. 13 : 157-163 (Eds E.

Naylor& R. Hartnoll. Oxford: Pergamon Press).

Edwards, H. Milne 1837. Histoire naturelledes Crustaces. II. Paris. 53 1 pp.
Fincham, A. A. 1977. Larval development of British prawns and shrimps (Crustacea: Decapoda:

Natantia). 1. Laboratory methods and a review of Palaemon (Palaeander) elegans Rathke, 1837.

Bull. Br. Mus. nat. Hist. (Zool.)31 (1) : 1-28.
1978. Larval development of British prawns and shrimps (Crustacea: Decapoda: Natantia). 2.

Palaemonetes(Palaemonetes) varians (Leach, 18 14) and morphological variation. Bull. Br. Mus. nat.

///s/.(Zool.)35(2): 163-182.

1979. Larval development of British prawns and shrimps (Crustacea: Decapoda: Natantia). 3.

Palaemon (Palaemon) longirostris H. Milne Edwards, 1837 and the effect of antibiotic on

morphogenesis. Bull. Br. Mus. nat. Hist. (Zool.) 37 (1 ) : 1 7^46.
Fincham, A. A. & Williamson, D. I. 1978. Crustacea, Decapoda: Larvae. VI Caridea, Families

Palaemonidae and Processidae. Ficht. Ident. Zooplancton, 159/160: 8 pp.
Forward, R. B. & Cronin, T. W. 1978. Crustacean larval phototaxis: possible functional significance.

In: Proc. 12th Eur. mar. Biol. Sym. 12:253-261 (Eds D. S. McLusky & A. J. Berry. Oxford:

Pergamon Press).
Foxon, G. E. H. 1934. Notes on the swimming methods and habits of certain crustacean larvae. J.

mar. biol. Ass. U.K. 19 : 829-849.

Gurney, R. 1942. Larvae of decapod Crustacea. 306 pp. Ray Society, London.
Hardy, A. C. & Bainbridge, R. 1954. Experimental observations on the vertical migrations of

plankton animals. J. mar. biol. Ass. U.K. 33 : 409-448.
Holthuis, L. B. 1950. The Palaemonidae collected by the Siboga and Snellius expeditions with

remarks on other species. 1 . Subfamily Palaemoninae. Siboga Exped. 39a : 1-268.
Keeble, F. & Gamble, F. W. 1904. The colour physiology of the higher Crustacea. Phil. Trans. R. Soc.

Lond. 8196:295-388.
Laverack, M. S., Macmillan, D. L. & Neil, D. M. 1976. A comparison of beating parameters in larval

and post-larval locomotion systems of the lobster Homarus gammarus (L.). Phil. Trans. R. Soc.

Lond. 8274:87-99.
Macmillan, D. L., Neil, D. M. & Laverack, M. S. 1976. A quantitative analysis of exopodite beating in

the larvae of the lobster Homarus gammarus (L.). Phil. Trans. R. Soc. Lond. B 274 : 69-85.
Man, J. G. De 1915. On some European species of the genus Leander Desm., also a contribution to

the fauna of Dutch waters. Tijdschr. ned. dierk. Vereen. Ser. 2, XIV : 115-1 79.
Mayer, P. 1877. Zur Entwicklungsgeschichte der Dekapoden. Jena. Z. Med. Naturw. 11 : 188-269.
Neil, D. M., Macmillan, D. L. & Laverack, M. S. 1976. The structure and function of thoracic

exopodites in the larvae of the lobster Homarus gammarus (L.). Phil. Trans. R. Soc. Lond. B

274 : 53-68.

Pennant, T. 1777. British Zoology. 4 : 136 pp.
Reeve, M. R. 1969. Growth, metamorphosis and energy conversion in the larvae of the prawn,

Palaemon serratus. J. mar. biol. Ass. U.K. 49 : 77-96.
Risso, A. 1816. Histoire naturelle des Crustaces des environs de Nice. Paris a la libraire

Greque-Latine-Allemande. 175pp.

A. 1 826. Histoire naturelle des principales productions de {'Europe meridionale. 5 : 403 pp.

Russell, F. S. 1925. The vertical distribution of marine macroplankton. An observation on diurnal

change. /. mar. biol. Ass. U.K. 13 : 769-809.
1927. The vertical distribution of marine macroplankton. V. The distribution of animals caught

in the ring-trawl in the daytime in the Plymouth area. J. mar. biol. Ass. U.K. 14 : 557-608.
Sandifer, P. A. & Smith, T. I. J. 1979. Possible significance of variation in the larval development of

palaemonid shrimp. J. exp. mar. Biol. Ecol. 39 : 55-64.

Savage, R. E. 1926. The plankton of a herring ground. Fish. Invest. Lond. 9 : 1-35.
Sharp, B. 1893. Catalogue of the crustaceans in the museum of the Academy of Natural Sciences of

Philadelphia. Proc. Acad. nat. Sci. Philad. 104-127.
Sollaud, E. 1912. Les metamorphoses du 'Bouquet', Leander serratus Pennant. C. R. Acad. sci. Paris

154 : 664-666.
1921. Le comportment des larves de Palaemonetes varians microgenitor Boas. Changement de

signe du phototropisme apres la metamorphose. Bull. Ass. fr. Avanc. Sci. Congres de Rouen

1921:671-673.
1923. Le developpement larvaire des Palaemoninae. Bull. biol. Fr. Belg. 57 : 509-603.

LARVAL DEVELOPMENT OF P. (P.) SERRATUS 161

Sui ton, A. H., Main, G. & Ronald, A. 1969. An instrument for counting the larvae of the prawn

Palaemon serratus and the brine shrimp Anemia salina. Lab. Pract. 18 : 433^36.
Thompson, W. V. 1836. Memoir on the metamorphosis in the Macrourae or long-tailed Crustacea,

exemplified in the prawn (Palaemon serratus). Edinb. New phil. J. 21 : 221-223.
Wickins, J. F. 1972. Developments in the laboratory culture of the common prawn Palaemon serratus

Pennant. Fishery Invest. Lond. Series 2 27 (4) : 1-23.
Williamson, H. C. 1915. Nordisches Plankton. VI. Crustacea Decapoda. Larven. Nord. Plankt.

6:315-588.

Manuscript accepted for publication 1 1 June 1982.

The larval development of the Angular Crab,
Goneplax rhomboides (Linnaeus) (Decapoda:
Brachyura)

R. W. Ingle & Paul F. Clark

Department of Zoology, British Museum (Natural History), Cromwell Road, London
SW7 5BD

Introduction

The Angular Crab, Goneplax rhomboides (Linnaeus) occurs in the Eastern Atlantic Ocean
and Mediterranean Sea. It has been reported from the northern Irish Sea to as far south as the
Cape region of South Africa (see Barnard, 1950 : 285; Ingle, 1980 : 109); the species occurs
from the lower shore to depths of about 700 m.

Capart (1951 : 1 69) discussed regional variation of this species with respect to the degree of
development of the posterior pair of carapace anterio-lateral teeth and differences in shapes
of the male first pleopod. He suggested two 'varieties' may exist. Specimens attributed to G.
rhomboides (L.) have a very rudimentary pair of posterior teeth and are reported only from
the Mediterranean Sea, coast of Mauritania and the Canary Islands whereas material
assigned to G. angulata (Pennant) has been recorded from various Atlantic Ocean localities
(see Manning & Holthuis, 1981 : 164).

The larval stages of G. rhomboides have been described previously (see larval and
post-larval references below), but these accounts are generally inadequate for use in detailed
comparative studies of larval morphology. The recent rearing of G. rhomboides to third crab
stage has provided sufficient material for redescribing the complete larval development of
this species and an account is given here of the four zoeal and megalop stage.

Materials and Methods

After several unsuccessful trawling attempts, SCUBA diving was used to collect ovigerous
material. On the advice of Alan Howard (MAFF) members of the BM(NH) Diving Unit
searched the sandy-mud substrate to a depth of 18m off Shoalstone Point (SX937568),
Brixham, Devon. An ovigerous crab was collected on 10 July 1981 and transported to the
rearing laboratory of the Crustacea Section, BM(NH). The larvae were reared using methods
described by Rice & Ingle (1975) and Ingle & Clark (1977), except that sea water was
untreated. Drawings and measurements were made with the aid of a camera lucida.
Measurements are as follows: total lengths of zoeae (T.T.) measured from tip of dorsal to tip
of rostral spine and carapace length (C.L.) measured from between eyes to posterio-lateral
margin of carapace (for zoeae) and from rostral tip for megalop. All material was fixed in
Steedman's preservative (Steedman, 1976 : 148) and later transferred to 70% ethanol
alcohol. The female and larval stages are deposited in the collections of the BM(NH),
accession numbers 1981 : 540 & 1982 : 55 respectively.

Descriptions

Goneplax rhomboides (Linnaeus, 1 758)

non Gonoplax rhomboides:-Cano, 1891, Tav. XI, figs ID (or ?E), IXd, IXe (megalops); Brachynotus
sexdentatus:-Cano, 1891, Tav. XI, fig. IF (crab stage); non Gonoplax rhomboides:-Wi\\iamson, 1915,

Bull. Br. Mm. not. Hist. (Zool.) 44(2): 1 63-1 77 Issued 24 February 1983

164

R. W. INGLE & P. F. CLARK

Fig. 1 Goneplax rhomboides (L.): a-d lst-4th zoeae; e megalopal carapace from left lateral
aspect f; megalop from dorsal aspect; g moult of megalopal abdomen slightly flattened to show
setation; scale, each division = 0- 1 mm.

LARVAL DEVELOPMENT OF ANGULAR CRAB

Goneplax rhomboides (L.): a-d antennule of 1 st-4th zoea respectively and e of megalop;
f-i antenna of lst-4th zoea and j of megalop respectively; scale = 0- 1 mm.

fig. 398 (after Cano); Gonoplax angulata:- Caroli, 1927: 161 (lst-4th zoeae, megal., describ.);
Gonoplax rhomboides:- Lebour, 1928 : 534, figs 4 (6-9), 5 (22-24), PI. II, fig. 6, PI. XI, fig. 10, PI. XII,
figs 1-4 (lst-4th zoeae, megal., lst-4th crab); Gonoplax angulata.-Bourdi lion-Casanova, 1960 : 180,
figs 57a-c (1st zoea, megal.); Goneplax rhomboides:- Rice & Williamson, 1977 : 55, fig. 29 (3rd zoea).

FIRST ZOEA

Dimensions: 1.1. 1-5 mm,C.L. 0-5 mm.

Carapace (Fig. la): Dorsal, rostral and lateral spines present; a pair of posterio-dorsal

166

R. W. INGLE & P. F. CLARK

Fig. 3 Goneplax rhomboides (L.): a-c abdomen and telson of lst-3rd zoea respectively from
dorsal aspect and d-f same from lateral aspect; g, h left half of mandible of 1st and 4th zoea
respectively (drawn from scanning EM photographs); scale, each division = 0-1 mm except

LARVAL DEVELOPMENT OF ANGULAR CRAB

167

Fig. 4 Goneplax rhomboides (L.): a abdomen and telson of 4th zoea from dorsal aspect; b of
another specimen from lateral aspect; c, d 1st maxilliped of 1st and 2nd zoea respectively; scale,
each division = 0-1 mm.

setules; dorso-median elevation present; posterior margin of carapace minutely serrate and

with 3-4 setules.

Eyes: Partly fused to carapace.

Antennule (Fig. 2a): Exopod unsegmented, with 2 terminal aesthetascs and one seta.

Antenna (Fig. 2f): Exopod with very minute spinules distally and with 2 median spinules and

2 setules; spinous process distally spinulate, slightly longer than exopod.

168

R. W. INGLE & P. F. CLARK

Fig. 5 Goneplax rhomboides (L.): a, b 1st maxilliped endopods of 3rd and 4th zoea respectively;
c, d 2nd maxillipeds of 1st and 2nd zoea and e, f 2nd maxilliped endopods of 3rd and 4th zoea
respectively; g maxillule of 1 st zoea; scale = 0- 1 mm.

LARVAL DEVELOPMENT OF ANGULAR CRAB 169

Mandible (Fig. 3g): Incisor and molar processes developed.

Maxillule (Fig. 5g): Endopod 2 -segmented, proximal segment with one seta, distal with 2

sub-terminal and 4 terminal setae; basal endite with one seta and 4 spines on distal margin;

distal and inner margins of coxal endite with a total of 6 setae.

Maxilla (Fig. 7a): Scaphognathite with 4 long plumose setae and one distal stout posterior

process; endopod bilobed, with 5 + 3 setae; basal endite unequally bilobed, with 4 + 5 setae;

coxal endite bilobed with 4 + 4 setae.

First maxilliped (Fig. 4c): Exopod incipiently 2-segmented, with 4 terminal plumose setae;

endopod 5-segmented, with 3,2, 1,2,4+1 setae; margin of basis with 2, 2, 3, 3 setae.

Second maxilliped (Fig. 5c): Exopod incipiently 2-segmented, with 4 terminal plumose

setae; endopod 3-segmented, with 1, 1,4+1 setae; margin of basis with 4 setae.

Third maxilliped'. not developed.

Pereiopods: not developed.

Abdomen (Figs 3a, d): 5-segmented + telson, segments 2-4 each with a pair of lateral

processes decreasing in size on each respective segment; posterio-lateral margins of segments

with minute denticles as shown in inset to Fig. 3d; margin of segment 2 produced and

rounded, those of 3-5 with acute processes; each posterio-dorsal margin of segments 3-5

with minute denticles and of 2-5 with a pair of small setules. Telson broad, one long dorsal

and one lateral spine on each fork; posterior margin concave, with 3 spines on each outer

half, outermost pair longest; middle portion of telson forks invested with minute spinules.

SECOND ZOEA

Dimensions: T.T. 1-9-2-0 mm, C.L. 0-6-0-7 mm.

Carapace (Fig. Ib): Now with 2 pairs of anterio-dorsal setules, 4-6 setules on posterior

margin and a prominent dorso-median elevation; eyes free.

Antennule (Fig. 2b): Exopod now with 3 terminal aesthetascs.

Antenna (Fig. 2g): Exopod setules longer than in previous stage, an incipient endopod bud

present.

Mandible: Unchanged.

Maxillule (Fig. 6a): Endopod now conspicuously stepped distally; basal endite with a

prominent plumose seta on outer margin, distal and inner margins with a total of 3 setae and

5 spines; distal and inner margins of coxal endite with a total of 7 setae.

Maxilla (Fig. 7b): Scaphognathite now with 12 marginal setae.

First maxilliped (Fig. 4d): Exopod now with 6 terminal plumose setae.

Second maxilliped (Fig. 5d): Exopod now with 7 terminal plumose setae.

Third maxilliped: represented as a small bud.

Pereiopods: represented as small buds.

Abdomen (Figs 3b, e): Dorsal surface of 1st segment with one seta, posterio-lateral margin

now slightly produced, lateral processes on segment 2 and posterio-lateral processes on 3-5

longer than in previous stage.

THIRD ZOEA

Dimensions: T.T. 2-8-2-9 mm, C.L. 1-1-1-2 mm.

Carapace (Fig. Ic): Now with 5 pairs of anterio-dorsal setules and 7-10 setules on posterior

margin.

Antennule (Fig. 2c): Exopod now with 3 setules and 3 setae.

Antenna (Fig. 2h): Endopod bud well developed.

Mandible: Incisor sub-divided.

Maxillule (Fig. 6b): Basal endite now with 3 setae on distal margin and with a total of 9 setae

on distal and inner margins of coxal endite.

Maxilla (Fig. 7c): Scaphognathite now with 20 setae, basal endite with 5 + 5 and coxal with

4 + 5 setae.

First maxilliped (Fig. 5a): Exopod now with 8 terminal plumose setae; distal segment of

endopod now with 5 + 1 setae.

170

R. W. INGLE & P. F. CLARK

Fig. 6 Goneplax rhomboides (L.): a-c maxillule of 2nd-4th zoea respectively; scale = 0- 1 mm.

Second maxilliped (Fig. 5e): Exopod now with 8 terminal plumose setae; distal segment of

endopod with 5 + 1 setae.

Third maxilliped: represented as a conspicuous biramous bud.

Pereiopods: rudimentary but conspicuous, first pair incipiently chelate.

Abdomen (Figs 3c, 0: Now 6-segmented + telson; a minute lateral process on segment 5 in

some specimens; posterio-lateral processes on segments 3-5 longer than in previous stage;

LARVAL DEVELOPMENT OF ANGULAR CRAB

171

Fig. 7 Goneplax rhomboides (L.): a, b maxilla of 1 st and 2nd zoea; c, d endopod, basal and coxal
endites of maxilla of 3rd and 4th zoea respectively; scale = 0- 1 mm.

dorsal surface of 1st segment now with 3 setae; rudimentary paired pleopods on segments

2-5.

FOURTH ZOEA

Dimensions: T.T. 3-5-3-6 mm, C.L. 1-4-1-5 mm.

Carapace (Fig. Id): Now with 8 or more pairs of anterio-dorsal setules, 2 pairs at base of

172 R. W. INGLE & P. F.CLARK

rostral spine and sometimes a small setule on each eye; 12-1 5 setules on posterior margin of

carapace.

Antennule (Fig. 2d): Exopod now with 4 terminal aesthetascs and short setae; endopod

represented as an incipient bud.

Antenna (Fig. 2i): Exopod now with conspicuous distal spinules; endopod bud more than

half length of exopod.

Mandible (Fig. 3h): Incisor and molar processes sub-divided as shown.

Maxillule (Fig. 6c): Distal and inner margins of basal endite now with a total of 7 setae and 7

spines; margins of coxal endite with a total of 10 setae.

Maxilla (Fig. 7d): Scaphognathite now with 31 marginal setae; margins of basal endite with

6 + 6 and coxal with 4-1-6 setae respectively.

First maxilliped (Fig. 5b): Exopod now with 9 terminal plumose setae; distal segments of

endopod proportionally slightly longer than in previous stage.

Second maxilliped (Fig. 50: Exopod now with 10-1 1 terminal plumose setae; segments of

endopod proportionally longer than in previous stage.

Third maxilliped'. more conspicuous than in previous stage.

Pereiopods: more developed than in previous stage.

Abdomen (Figs 4a, b): Segment 6 now with minute denticles on posterio-dorsal margin and

with a pair of pleopods; segments 1, 2, 3 with 5, 4, and 3 dorsal setae respectively; pleopods

biramous. Medio-posterior margin of telson with 3 setae, dorsal surface with a pair of median

setae.

MEGALOP

Dimensions: C.L. 1-8-1-9 mm.

Carapace (Figs le-f): Rostrum small, slightly deflected ventrally; mesogastric region with a

prominent longitudinal carina; each half of protogastric region with a prominent curved

spine; cardiac and intestinal regions with carinae and broad tubercles arranged as shown in

Fig. If; margin of carapace with numerous small setules.

Antennule (Fig. 2e): Peduncle 3-segmented, with 2 setae on each segment; exopod

4-segmented with 0, 5, 4, 3 aesthetascs and 0, 0, 2, 2 setae respectively; endopod

unsegmented, with one sub-terminal and 5 terminal setae.

Antenna (Fig. 2j): Peduncle 3-segmented, with 1,1,0 setae and flagellum 7-segmented with

1 , 0, 2, 5, 0, 4, 4 setae respectively.

Mandible (Fig. 9e): Molar process now reduced, palp 3-segmented, with 0, 1, 8 setae

respectively.

Maxillule (Fig. 8a): Endopod now reduced and unsegmented, with 2 terminal setae; margins

of basal endite with a total of 1 3 setae and 8 spines; margins of coxal endite with a total of 1 5

setae/spines.

Maxilla (Fig. 8b): Scaphognathite with 51 marginal setae and 4 setae on dorsal surface,

posterior margin sub-truncate; endopod reduced to a sub-acute lobe with setae on outer

margin; basal endite with 8 + 7 marginal setae and with additional setae on dorsal and ventral

surfaces as shown; coxal endite with 6 + 9-10 setae.

First maxilliped (Fig. 8c): Coxal segment with 6-7 setae, basis with 26-28 setae; endopod

represented as a broad sub-acute lobe invested with 3-4 setae; exopod 2-segmented, with 3

and 5 setae respectively; epipod well developed, with 6 long setae.

Second maxilliped (Fig. 8d): Coxal segment hardly differentiated from basis, with 5-6 setae,

ischium to dactylus differentiated, with 0, 3, 1, 4, 5 setae respectively in addition to 4 spines

on dactylar margin; exopod 2-segmented, with 2 and 4 setae respectively; 2 setae at

basis-exopod junction; epipod short, with 3 distal setae.

Third maxilliped (¥\g. 9a): Coxa not differentiated from basis, with 4-5 setae as shown; outer

margin of ischium with 1-2 broad, acute spines and with 19-20 setae; merus to dactylus well

differentiated and with 1 1-12, 5, 7, 6 setae respectively; exopod 2-segmented, with 1 and 5

setae respectively; epipod long, with numerous short setae in proximal half (circa 18) and

1 5 long medio- to distally placed setae.

LARVAL DEVELOPMENT OF ANGULAR CRAB

173

Fig. 8 Goneplax rhomboides (L.): megalop-a maxillule; b maxilla; c 1st maxilliped; d 2nd

maxilliped; scale = 0-1 mm.

Pereiopods (Figs 9b-d, lOa, b, i): Cheliped stout, invested with numerous setae as shown in
Fig. 9b; one large and one small ischial spine present; inner margin of propodal extension
with 2-3 processes, inner margin of dactylus without processes. Pereiopods stout, setose as
shown in Figs 9c, d & lOa, b; coxal-ischial segments of pereiopods 2-4 each with a well
developed spine; dactylus of 5th pereiopod with 3 long setae on inner distal margin.

174

R. W. INGLE & P. F. CLARK

Fig. 9 Goneplax rhomboides (L.): megalop - a 3rd maxilliped; b left cheliped; c 2nd pereiopod; d
3rd pereiopod; e mandible; each division of scale = 0-1 mm.

Cephalothorax (Fig. lOi): Second to 4th sternites each with a prominent curved spine and a
seta, first segment of sternum also with a small spine and numerous setae.
Abdomen (Figs If, g & lOh): 6-segmented + telson; posterio-lateral margin of first segment
sub-acute, of 2nd truncate, of 3rd-5th acutely produced and of 6th sub-truncate. Surfaces of
segments invested with numerous setae distributed as shown in Fig Ig. Well developed

LARVAL DEVELOPMENT OF ANGULAR CRAB

175

Fig. 10 Goneplax rhomboides (L.): megalop-a-b 4th and 5th pereiopods and c-f lst-4th
pleopods respectively; g telson and left uropod from dorsal aspect; h abdomen from right lateral
aspect; i sternites and coxal-ischial segments of pereiopods from left side, ventral aspect; scale,
each division = 0-

mm.

biramous pleopods on segments 2-5, exopods with 17, 17, 16, 15 long plumose setae on
lst^4th pairs (Figs lOc-f) respectively; inner distal margin of endopod of each with 3
coupling hooks. Uropods (Fig. lOg) well developed, distal segment with 7-8 long plumose
setae. Telson much broader than long, dorsal surface with a pair of lateral and 2 pairs of
median setules, ventral surface with 3-4 small setules.

176

R. W. INGLE & P. F. CLARK

Remarks

The present laboratory reared material of G. rhomboides differs in a number of features from
the accounts given by Bourdil Ion-Casanova (1960) and Rice & Williamson (1977). These
differences are tabulated below.

Bourdillon-Casanova

ZOEA!

Denticles on proximal part of posterio-lateral
margin of abdominal segments very pronounced.

MEGALOP

Disto-lateral margins of rostrum very acute.
Protogastric spines of carapace stout and straight.
A pair of widely spaced tubercles on meta-
branchial-intestinal regions.
Groups of setae on posterior region of carapace

Exopod of uropod with 8-9 setae

Rice & Williamson

ZOEA III
Antennal exopod with a single mid-point seta.

Scaphognathite of maxilla with 1 8-19 setae.
Endopod of 2nd maxilliped with 1,1,5 setae.

ZOEAE 1-IV

Exopod terminal segment of 2nd maxilliped with
4, 7,9,11 setae in respective stages.

Present material

ZOEA I

Denticles on proximal part of posterio-lateral
margin of abdominal segments very minute.

MEGALOP

Disto-lateral margins of rostrum not acute.

Protogastric spines of carapace thin and curved.

A pair of tubercles placed near to median line on

cardiac region.

Without groups of setae on posterior region of

carapace.

Exopod of uropod with 7-8 setae.

ZOEA III

Antennal exopod with more than one seta/spinule
at mid-point.

Scaphognathite of maxilla with 20 setae.
Endopod of 2nd maxilliped with 1,1,6 setae.

ZOEAE I-IV

Exopod terminal segment of 2nd maxilliped with
4, 7, 8, 10-1 1 setae in respective stages.

With the exception of Geryon tridens (Kroyer), the zoeae of Goneplax rhomboides can
be distinguished from those of other known brachyrhynchs occurring in the N.E. Atlantic sea
area (see Ingle, 1980) by the following combined features: (1) A pair of small but prominent
dorso-lateral processes on the 4th segment of the abdomen and sometimes a minute pair on
the 5th segment in the 3rd and 4th stages. (2) The antennal exopod with spinules and setae
sub-terminally placed. Features separating zoeae of G. rhomboides from those of Geryon
tridens were tabulated by Ingle (1979 : 229). The following amendments must now be made
to this table with respect to G. rhomboides: (1) The antennal exopod-the spinous process is
longer than the exopod in all stages. (2) Maxilla of ZHI-scaphognathite with a maximum of
20 setae on margin. (3) 1st maxilliped-endopod setae of ZIII, G. tridens 2, 2, 1, 2, 5+ 1 and
G. rhomboides 3, 2,1,2,5+1 respectively.

Acknowledgements

We express our thanks to the following persons. Alan Howard, Fisheries Laboratory, MAFF,
Burnham-on-Crouch, Essex, for detailed locality information that enabled us to collect
material. Drs David George and Howard Platt without whose support the diving programme
could not have been realized; John Tapp and Brian Maddock, ICI Marine Laboratory,
Brixham, Devon, who provided facilities for keeping live crabs and helped us in many other
ways. We also thank Don Claugher for providing scanning photographs that confirmed some
morphological features.

LARVAL DEVELOPMENT OF ANGULAR CRAB 1 77

References

Barnard, K. H. 1950. Descriptive catalogue of South African Decapod Crustacea (Crabs and Shrimps).

Ann. S. Afr. Mus. 38 : 1-837.
Bourdillon-Casanova, L. 1960. Le meroplancton du Golfe de Marseille: Les larves de crustaces

decapodes. Reel. Trav. Stn mar. Endoume30 : 1-286.
Capart, A. 1951. Crustaces Decapodes, Brachyures. Result, sclent. Exped. oceanogr. belg. Eaux cot.

afr. Atlant. Sud. Ill (I) : 1 1-205.
Caroli, E. 1927. Sviluppo larvale della Gonoplax angulata (Pennant). Boll. Soc. Nat. Napoli

38: 161-166.
Ingle, R. W. 1979. The larval and post-larval development of the brachyuran crab Geryon tridens

Kroyer (Family Geryonidae) reared in the laboratory. Bull. Br. Mus. nat. Hist. (Zool.) 36 : 2 1 7-232.
1980. British Crabs, vi + 222 pp. British Museum (Natural History) & Oxford University Press,

London & Oxford.

& Clark, P. F. 1977. A laboratory module for rearing crab larvae. Crustaceana 32 : 220-222.

Lebour, M. V. 1928. The larval stages of the Plymouth Brachyura. Proc. zool. Soc. Lond. 2 : 473-560.
Manning, R. B. & Holthuis, L. B. 1981. West African Brachyuran Crabs (Crustacea: Decapoda).

Smithson. Contr. Zool. 306 : i-xii, 1-379.
Rice, A. L. & Ingle, R. W. 1975. The larval development of Carcinus maenas (L.) and C.

mediterraneus Czerniavsky (Crustacea, Brachyura, Portunidae) reared in the laboratory. Bull. Br.

Mus. nat. Hist. (Zool.) 28 : 101-1 19.
& Williamson, D. I. 1977. Planktonic stages of Crustacea Malacostraca from Atlantic Seamounts.

Meteor ForschErgebn. D 26 : 28-64.
Steedman, H. F. (Ed.) 1976. Zooplankton fixation and preservation. In: Monographs on oceanographic

methodology. 350 pp. Paris.

Manuscript accepted for publication 1 1 June 1982

The larval and first crab stages of three Inachus
species (Crustacea: Decapoda: Majidae); a
morphological and statistical analysis

Paul F. Clark

Department of Zoology, British Museum (Natural History), Cromwell Road, London
SW7 5BD

Introduction

Several authors have acknowledged difficulties in distinguishing between congeneric
brachyuran crab- larvae (see Lebour, 1928 : 546; Hartnoll, 1961 : 181; Christiansen, 1969;
Rice & Ingle, \915a & 19756; Ingle, 1982). These observations were based on a limited
amount of material that did not permit statistical analysis of larval characters. Rearing large
numbers of crab larvae (see Ingle & Clark, 1977) provided sufficient material for this
statistical study. A multivariate technique was used to examine the larvae and first crab stage
of three species of spider crabs belonging to the genus Inachus.

Material & Methods

Berried females of Inachus dorsettensis and /. phalangium were collected by trawl from
localities off Port Erin, Isle of Man, and Plymouth and /. leptochirus was trawled from
Modiolus beds four miles south of Spanish Head, Isle of Man. The adult females, together
with the larvae used in this study are deposited in the BM(NH). Larvae were reared using
methods described by Ingle & Clark (1977), then fixed and preserved in 80% alcohol. Twenty
specimens of each stage were dissected and mounted as permanent slide preparations in
lignin pink/poly vinyl lactophenol. For the multivariate study 43, 142 & 178 characters were
used for zoeal, megalop and first crab stages respectively. The majority of these characters
are meristic, e.g. setal counts on appendages, but a few were present or absent scores.
Accurate measurements of spines and carapace dimensions, as well as carapace setal counts
of megalops and crab stages proved to be impracticable and were not used. Setal counts were
scored for one side of the body although on occasions it was necessary to combine parts of
both left and right appendages to form a complete score. The data was subjected to Principal
co-ordinate analysis according to Gower (1966). This method summarizes similarities
between OTUs as a 2-dimensional plot. The computation was carried out using a varian V
72 computer. Each larval stage was analysed separately to avoid major differences between
stages swamping any specific variation.

Results
Statistical Analysis

First and second principal co-ordinates were plotted for zoea II, megalops and first crab stage
of each species. The zoea I stage data was not computed because only two characters were
considered significant on inspection. The OTUs in zoea II (Fig. 1) can be separated into two
groups, /. leptochirus and /. dorsettensis/I. phalangium whereas in both megalops (Fig. 2)
and first crab stage (Fig. 3) they are clearly separated into three groups which correspond to
the three species.

Bull. Br. Mas. nat. Hist. (Zool)44(2): 179-190 Issued24 February 1983

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SECOND PRINCIPAL CO-ORDINATE

Fig. 1 A plot of the 1st & 2nd Principal co-ordinates of zoea II. Scores of variate 1 (range 5, 6, 7),
variate 1 1 (range 16, 17, 18, 19, 20) and variate 36 (range 0, 2) are plotted against their OTUs.
OTUs 1-20 /. leptochirus, 21-40 /. dorsettensis, 41-60 /. phalangium. The dotted line divides
the OTUs into two groups, group 1 =1. leptochirus and group 2 — 1. dorsettensis/I. phalangium.
Variate 36 is the only diagnostic character separating the two groups. Note that the dotted line
has no statistical significance.

The zoea I stages can be divided into two groups, /. leptochirus and /. dorsettensis/I.
phalangium, using the basal article of the second maxilliped and the posterio-dorsal margin
of the first abdominal somite. /. leptochirus has one seta on the basis (Fig. 4b) and two on the
first abdominal somite (Fig. 4c) whereas /. dorsettensis and /. phalangium have no setae at
either site (Fig. 4a, d). The first zoeal stages of/, dorsettensis and /. phalangium cannot be
separated on setal characters.

STATISTICAL ANALYSIS OF CRAB LARVAE

181

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SECOND PRINCIPAL CO-ORDINATE

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Fig. 2 A plot of the 1 st & 2nd Principal co-ordinates of megalops using 68 variates. OTUs 1-20 /.
leptochirus, 21-40 /. dorsettensis, 41-60 /. phalangium. These OTUs fall into 3 distinct groups
which correspond to the three British Inachus species.

The second zoeal stages can also be split into the same two groups (Fig. 1). The three
characters showing variation were the number of terminal aesthetascs on the antennule, the
numbers of setae on the margin of the maxillary endopod and on the posterio-dorsal margin
of the first abdominal somite. The scores of these three characters are shown respectively on
Fig. 1 in bold type, adjacent to their respective OTUs. Separation of the two groups shown by
the dotted line is determined only by one character, the number of posterio-dorsal marginal
setae on the first abdominal somite. /. leptochirus has 2 setae (Fig. 4c) whereas /. dorsettensis
and /. phalangium have none (Fig. 4d).

The megalops can be divided into three groups which correspond to the three species using
only 68 out of the original 142 characters (Fig. 2). Group separation remains constant how-
ever, if only nine characters are used.

By using combinations of the means of these nine characters it seems possible to separate
the megalops of the three species.

Nevertheless, their overlapping distribution (Table 2) makes separation very difficult in
practice as no single character separates all three species. For example, OTU 21 (I.
dorsettensis) is grouped with OTUs 52 and 53 (I. phalangium) on its overall similarity as
they have identical scores for all nine characters. Overlapping ranges of variation in numbers
of setae makes it impossible to differentiate all three species with absolute confidence at the

182

P. F. CLARK

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Fig. 3 A plot of the 1 st & 2nd Principal co-ordinates of the first crab stages using 1 38 variates.
OTUs 1-20 /. leptochirus, 21-40 /. dorsettensis, 41-60 /. phalangium. These OTUs fall into 3
distinct groups which correspond to the three British Inachus species.

megalop stage. Only the number of setae on the proximal exopod segment of the antennule
(Figs. 4e, f) displays no intraspecific variability and serves as a diagnostic character
separating /. leptochirus from /. dorsettensis/I. phalangium. The number of spines on the
merus of the first peraeopd is also a relatively good character separating /. leptochirus from
the other two species, but this is a particularly difficult character to observe because of the
thickness of the merus.

Differentiation of the first crab stage OTUs (Fig. 3) was achieved using 1 38 characters from
the original 178, but clustering of the OTUs corresponding to the three Inachus species does
not alter when the number of characters is reduced to 21 (Fig. 5). These 21 characters are
listed in Table 3.

As with the megalops, separation of the three species is marked when the means of the
variates (Table 4) are used, but again the distributions show considerable overlap. In

STATISTICAL ANALYSIS OF CRAB LARVAE

183

Fig. 4 2nd maxilliped, zoea I (a) /. dorsettensis & I. phalangium (b) /. leptochirus; abdomen of
zoea I & II (c) /. leptochirus (d) /. dorsettensis & I. phalangium; antennule of megalop (e) /.
leptochirus (f) /. dorsettensis & /. phalangium.

184 P.F.CLARK

Table 1 A list of characters that may separate the megalops of the three Inachm species

Variate no.

Characters

4
7

44
48
62
67
81
95
109

number of setae on proximal exopod segment of antennule
number of setae on first segment of antenna
number of setae on merus of 3rd maxilliped
number of setae on epipodite of 3rd maxilliped
number of spines on merus of 1st peraeopod
number of setae on propodus of 2nd peraeopod
number of setae on propodus of 3rd peraeopod
number of setae on propodus of 4th peraeopod
number of setae on propodus of 5th peraeopod

Table 2 Studying the means of each character from Table 1 , the megalops in theory are separable
using combinations of characters. However, if the distribution of each character is tabulated only
variate 4 is a good diagnostic character, but this only separates 7. leptochirus from /. dorsettensis/I.
phalangium (see Figs. 4e, 0- (L = 7. leptochirus, D = I. dorsettensis & P = 7. phalangium)

distribution of variate 4

1 2

L 0 20

D 20 0

P 20 0

variate 4 separates L from D & P

distribution of variate 7

0 1

L 0 20

D 2 18

P 15 5

variate 7 separates P from D & L

distribution of variate 44

4 5

L 1 19

D 18 2

P 16 4

variate 44 separates L from D & P

distribution of variate 48
0 1 2

LOO 7 13

D 1 9 8 2

P 0 5 10 5

variate 48 separates L from D & P

distribution of variate 62

2 3

L 00

D 0 20

P 415

variate 62 separates L from D & P

20
0

mean

2
1

mean
1

1
0

mean
5
4
4

mean
3

2
2

mean
4
3
3

distribution of variate 67

16 17 18 mean

L 3 17 0 17

D 19 1 0 16

P 0 19 1 17
variate 67 separates D from L & P

distribution of variate 81

15 16 17 mean

L 0 2 18 17

D 1 19 0 16

P 0 3 17 17
Variate 8 1 separates D from L & P

distribution of variate 95

15 16 17 mean

L 0 6 14 17

D 4 16 0 16

P 1 10 9 16
variate 95 separates L from D & P

distribution of variate 109

14 15 16 mean

L 1 2 17 16

D 0 20 0 15

P 1 18 1 15
variate 1 09 separates L from D & P

Note that the means have been rounded up to the nearest whole number.

STATISTICAL ANALYSIS OF CRAB LARVAE 185

Table 3 List of characters that may be used to separate the 1 st crab stages

Variate no. Characters

6 aesthetascs on 2nd exopod segment of antennule

9 setae on endopod of antennule

1 3 number of setae on 3rd segment of antenna

14 number of spines on 1st segment of antenna

2 1 number of setae on distal segment of mandibular palp

45 number of setae on basis of 2nd maxilliped

57 number of setae on coxa of 3rd maxilliped

94 number of setae on basis of 2nd peraeopod

99 number of spines on merus of 2nd peraeopod

1 00 number of spines on ischium of 2nd peraeopod

1 14 number of setae on ischium of 3rd peraeopod

1 1 5 number of setae on basis of 3rd peraeopod

1 20 number of spines on merus of 3rd peraeopod

1 2 1 number of spines on ischium of 3rd peraeopod

1 35 number of setae on ischium of 4th peraeopod

1 36 number of setae on basis of 4th peraeopod
141 number of spines on merus of 4th peraeopod
146 number of hooks on propodus of 4th peraeopod

1 56 number of setae on ischium of 5th peraeopod

1 57 number of setae on basis of 5th peraeopod

1 67 number of hooks on propodus of 5th peraeopod

practice, only a combination of characters can be used to distinguish between the species at
first crab stage.

Morphology

The general morphology of/, dorsettensis was described and illustrated by Ingle (1977).
Most of the setal counts fall within the variation recorded during the present study. This
indicates little or no temporal variation. Some of the discrepancies may be due to the
difficulty of classifying and objectively defining elements, as between a seta and a spine,
when the structures grade one into the other (Gurney, 1931 : 38). However, some disparity
between Ingle's study and the present work could not be accounted for.

Discussion

Williamson (1965 : 390) listed the presence of a seta on the outer margin of the maxillule
basal endite as one often characters for separating brachyuran larvae from anomuran larvae.
In previous descriptions of zoea II in majids this character is shown as present, for example,
Ingle (1977) records this seta as present in zoae II and megalops of Inachus reared from
Plymouth material — this was confirmed by re-examining Ingle's material and by rearing
fresh material from the Plymouth area. In this study the seta was absent from zoea II of/.
dorsettensis reared from the Isle of Man and from all three megalops.

Lebour* (1928) suggested that larvae of the three Inachus species could be separated on
size, chromatophore patterns and length of dorsal spines, but none of these claims could be
verified. Only the megalops and first crab stage of/, leptochirus in the present study proved to
be larger than those of the other two species. Larval inachinids have apomorphic zoeal
characters which were listed by Rice (1980 : 307), to which can now be added the absence of

*Lebour's material is no longer extant; Ingle, pers. comm.

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Fig. 5 A plot of the 1st and 2nd Principal co-ordinates of first crab stage using 2 1 variates. OTUs
1-20 7. leptochirus, 21-40 /. dorsettensis, 41-60 /. phalangium. Although the number of variates
is reduced from 138 to 21, the OTUs still fall into 3 distinct groups which correspond to the 3
British Inachus species. The grouping of the OTUs is similar to that in Fig. 3 and therefore
illustrates that the 21 characters selected contribute to the separation of the 3 groups. Note that
the groups /. leptochirus and /. dorsettensis have changed positions when compared with Fig 3;
this has no significance in the analysis.

STATISTICAL ANALYSIS OF CRAB LARVAE

Genus INACHUS

189

Genus MACROPODIA

group 1

I. leptochirus
I. thoracicus

group 2

I. dorsettensis
I. phalangium

M. tenuirostris

M. rostrata

2 setae present
on first
abdominal somite

First abdominal somite
without setae.

Zoea I without a
seta on basis of
2nd maxilliped

Distal endopod
segment of 2nd
maxilliped with
3 terminal setae.

Distal endopod segment of 2nd maxilliped
with h setae.

1 seta present on basis of 2nd maxilliped in zoea I
and absent in zoea II.

Zoea II with mandible palp and antennule endopod absent.

Fig. 6 Cladogram of known Inachus & Macropodia larval descriptions.

a mandibular palp and endopod bud on the antennule of zoea II. Similarly, when compared
with other majid larva characters the loss of paired dorsal setae on the first abdominal somite
and the absence of setae on the basis of the 2nd maxilliped in /. dorsettensis and /.
phalangium, can be considered as derived traits. The present study failed to reveal characters
which separate the larvae of/, dorsettensis from /. phalangium, but demonstrated that the
larvae of/, leptochirus can be easily recognized.

Adult males of/, leptochirus share one important feature with two other species of Inachus
(i.e. /. thoracicus & I. aquiarii) in having a sternal callosity, a character that is absent in
males of/, dorsettensis, I. phalangium and /. communissimus. Such a separation of Inachus
species into two groups, those with and those without a sternal callosity, is supported by the
present study. Heegaard (1963) studied the zoeae of/, thoracicus and clearly figures two setae
on the first abdominal somite (p. 475, Fig. 83), but not a seta on the basis of the 2nd
maxilliped (p. 475, Fig. 82). Unfortunately Heegaard's material is no longer extant.
Re-examination of /. thoracicus zoeae may well show that they are inseparable from /.
leptochirus, adding support to the suggestion that there are two natural groups in the genus
Inachus.

Present larval evidence supports the view that Inachus and Macropodia are the most
derived of all majids since they show the greatest reduction in numbers of setae; considered
by Rice (1980) to be the derived condition. A suggested phylogeny of well documented
larvae from the genera Inachus and Macropodia is shown in Fig. 6.

Setal studies of other brachyuran genera have shown that the larvae of species accepted as

190 P. F. CLARK

closely related are not usually separable on quantitative characters. Therefore meristic setal
incongruities within genera, as shown here for Inachus, may be the only morphological
evidence of phylogenetic non-homogeniety.

This project formed part of an M.Sc. degree in Modern Taxonomy. All relevant data and
larval figures were deposited in the Crustacea Section, BM(NH) and the Library of the
Polytechnic of Central London.

Acknowledgements

I wish to thank Drs Roger Lincoln, Ray Ingle and Geoff Boxshall, Crustacea Section
BM(NH), for their help and critical comments on earlier drafts of this paper. For help with
collection of ovigerous crabs, I thank Mr Tony Mattacola, Plymouth Marine Laboratory, the
crews of the research vessels, Sarsia, Sepia & Squilla (Plymouth Marine Laboratory) and
Cuma & Silver Spray (Port Erin, Isle of Man) and Drs D. I. Williamson & Richard Hartnoll
(Port Erin Marine Station, University of Liverpool). Miss Joan Ellis, Crustacea Section,
kindly sorted through large quantities of Modiolus, and Dr M. Hills & Miss Kay Shaw,
Biometrics Section, gave invaluable statistical advice.

References

Christiansen, M. E. 1969. Marine invertebrates of Scandinavia. No. 2. Crustacea, Decapoda,

Brachyura. Universitetsforlaget, Oslo pp. 1-143. Oslo.
Clark, P. F. 1980. British Spider Crabs of the genus Inachus; a morphological study of larval

development. M.Sc. Modern Taxonomy (C.N.A.A.) Thesis. Polytechnic of Central London/City of

London Polytechnic.
Gower, J. C. 1966. Some distance properties of latent root and vector methods used in multivariate

analysis. Biometrika 53 (3-4) : 325-358.

Gurney, R. 1931. British Fresh- Water Copepoda. Vol. 1, 239 pp, Ray Society, London.
Hartnoll, R. G. 1961. A re-examination of the Spider Crab, Eurynome Leach from British waters.

Crustaceana2(3) : 171-182.
Heegaard, P. 1963. Decapod larvae from the Gulf of Napoli, hatched in captivity. Vidensk. Meddr

dansk. nalurh. Foren. 125 : 449-493.
Ingle, R. W. 1977. The larval and post-larval development of the Scorpion Spider Crab, Inachus

dorsettensis (Pennant) (Family: Majidae) reared in the laboratory. Bull. Br. Mus. nat. Hist. (Zool.)

30 (9) : 329-348.
1982. Larval and post larval development of the slender- legged Spider Crab, Macropodia

rostrata (Linnaeus) (Oxyrhyncha: Majidae: Inachinae), reared in the laboratory. Bull. Br. Mus. nat.

Hist. (Zool.) 42 (3) : 207-225.
Ingle, R. W. & Clark, P. F. 1977. A laboratory Module for rearing crab larvae. Crustaceana

32 (2): 220-222.

Lebour, M. V. 1928. The larval stages of the Plymouth Brachyura. Proc. zool. Soc. Lond. 2 : 473-560.
Rice, A. L. 1980. Crab zoeal morphology and its bearing on the classification of the Brachyura. Trans.

zool. Soc. Lond. 35 : 271-424.
Rice, A. L. & Ingle, R. W. 1975a. The larval development of Carcinus maenas (L.) and C.

mediterraneus Czerniavsky (Crustacea, Brachyura, Portunidae) reared in the laboratory. Bull. Br.

Mus. nat. Hist. (Zool.) 28 (3) : 101-1 19.
19756. A comparative study of larval morphology of the British Portunid crabs Macropipus

puber(L.) and M. holstatus (Fabricius), with a discussion of generic and sub-familial larval characters

within the Portunidae. Bull. Br. Mus. nat. Hist. (Zool.) 28 (4) : 1 2 1-1 5 1 .
Williamson, D. I. 1965. Some larval stages o"f three Australian crabs belonging to the families

Homolidae and Raninidae, and observations on the affinities of these families (Crustacea:

Decapoda). Aust. J. mar. Freshw. Res. 16 : 369-398.

Manuscript accepted for publication 18 June 1982.

British Museum (Natural History)
British Marine Amphipoda: Gammaridea

by R. J. Lincoln

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Zoology series Vol 44 No 3 31 March 1983

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ISSN 0007-1498 Zoology series

Vol 44 No 3 pp 191-247
British Museum (Natural History)
Cromwell Road
London SW7 5BD Issued 31 March 1983

A review of the Euplotidae (Hypotrichida,
Ciliophora)

Colin R. Curds & Irene C. H. Wu

Zoology Department, British Museum (Natural History), Cromwell Road, London
SW7 5BD

Contents

Introduction
Key to Genera .
Genus Discocephalus
Genus Diophrys
Genus Uronychia .
Genus Certesia .
Genus Gastrocirrhus
Genus Euplotaspis .
Genus Euplotidium .
Genus Paraeuplotes .
Genus Swedmarkia .
Genus Gruberella
Genus Cyatharoides.
References .
Index .

191
192
193
197

215
227
228
232
234
239
240
242
243
244
247

Introduction

Guides to the species of two genera of Euplotid ciliates, Euplotes Ehrenberg in Hemprich
and Ehrenberg, 1831 and Aspidisca Ehrenberg, 1830, have been published in recent years
(Curds, 1975; Wu & Curds, 1979). The other genera in the family Euplotidae Ehrenberg,
1838 contain fewer species but there are still identification problems in some. The present
work is intended to aid the specific identification of the remaining nine genera which Borror
(1972) grouped together into the Euplotidae, another more recently described genus and one
other addition. Although four of these genera only contain single species it was thought
worthwhile to include them for completeness. The genera included here are in chronological
order of authority. Discocephalus Ehrenberg in Hemprich and Ehrenberg, 1828; Diophrys
Dujardin, 1841; Uronychia Stein, 1859; Certesia Fabre-Domergue, 1885; Gastrocirrhus
Lepsi, 1928; Euplotaspis Chatton and Seguela, 1936; Euplotidium Noland, 1937;
Paraeuplotes Wichterman, 1942; Swedmarkia Dragesco, 1954; Gruberella Corliss, 1960 and
Cyatharoides Tuffrau, 1975.

Members of the Euplotidae are hypotrichs with the characteristically prominent adoral
zone of membranelles (AZM) arranged at the anterior left of the ventral surface bordering a
wide peristome. In certain genera the AZM may continue over the apical end of the body
onto the dorsal surface. Unfortunately there is no set of characters which will include all of
Borror's (1972) genera into the family. This could well indicate that it is not a natural family.
The cirri on the ventral surface are arranged in distinct groups but they are not the only
hypotrichs to have this feature. For example, the Oxytrichidae Ehrenberg, 1838 also have
grouped cirri, and Borror (1972) distinguished them from the Euplotidae by their possession
of only a few left marginal and no right marginal cirri, even so there are several exceptions to

Bull. Br. Mus. nat. Hist. (Zool.)44(3): 191-247

Issued 31 March 1983

191

192 C. R. CURDS & I.C. H. WU

this rule. Furthermore, while right caudal cirri are present in Diophrys, Discocephalus,
Euplotes and Uronychia, they are absent in others. However, transverse cirri are present in
all but one Euplotid genus. With this state of affairs, perhaps it is not surprising that there is
some disagreement in the literature as to what constitutes the family Euplotidae. Borror
(1972) included Aspidisca in the family but Stein (1859a), Biitschli (1889), Kahl (1932),
Faure-Fremiet (1961) and Corliss (1961, 1977, 1979) all maintain it in a separate family the
Aspidiscidae Ehrenberg, 1838. Corliss (1979) included four genera in the family
Aspidiscidae; Aspidisca, Euplotaspis, Onychaspis Stein, 1859 and Paraeuplotes (as an
incertae sedis). The genus Onychaspis differs from Aspidisca only by the former's possession
of a larger number of transverse cirri and most authors consider it to be a synonym of
Aspidisca (Borror, 1972; Wu and Curds, 1979). Indeed, Corliss (1979) indicated this
possibility in his classification. One of the features of the Aspidiscidae is the great reduction
of oral membranelles, however this description would not fit the AZM of Euplotaspis or
Paraeuplotes. Corliss (1979) also placed three of the genera being considered here
(Cirrhogaster Ozaki and Yagui, 1941; Euplotidium and Gastrocirrhus) into the family
Gastrocirrhidae Faure-Fremiet, 1961 . Here the single species genus Cirrhogaster is regarded
as a member of the genus Gastrocirrhus as it only differs slightly in cirral number. Borror
(1972) included Gastrocirrhus in the Euplotidae but noted that its position in that family was
provisional.

It is clear from this brief synopsis that the position of these genera within three or a single
family group is still in a state of flux and to a large extent a matter of conjecture. It is not
the purpose of the present paper to attempt to assign the genera to any old, current or new
classification scheme; more data, particularly concerning their comparative morphogenesis,
are required before anything useful can be suggested. The aim here is to aid the marine
ecologist and protozoologist to identify the species of those genera which conveniently fall
within the single family Euplotidae.

Key to Genera

1 AZM conspicuous, in single anterior part 2

AZM inconspicuous, in 2 parts ASPIDISCA (see Wu& Curds, 1979)

2 Without frontoventral cirri, caudals never extremely large . . . GRUBERELLA(p.242)
With frontoventral cirri (when frontoventrals reduced and inconspicuous then caudals

usually very large)

3 With caudal cirri 4

Without caudal cirri 11

4 With marginal cirri, caudals sometimes very large 5

Without marginals, caudals present but never very large

5 Caudals very large and prominent 6

Caudals weak EUPLOTES (see Curds, 1975)

6 5- 10 conspicuous frontoventral cirri present, moves forwards . . DIOPHRYS (p. 197)
3 inconspicuous cirri present, moves backwards URONYCHIA(p.2l5)

1 Elongate with discoid 'head' region DISCOCEPHALUS (p. 193)

Ovoid to elongate, when elongate never with discoid 'head' region 8

8 Ovoid, dorsoventrally flattened 9

Elongate, rounded in section, often cup-shaped with funnel-shaped peristome opening

apically and ventrally 10

9 Cirri mainly in 2 rows, found on coral PARAEUPLOTES (p. 239)

Cirri in well-defined groups, found in sea-squirts EUPLOTASPIS (p. 232)

10 With 5-6 transverse cirri EUPLOTIDIUM (p. 234)

Without transverse cirri GASTROCIRRHUS (p. 228)

11 Without marginal cirri, rounded in section EUPLOTIDIUM (p. 234)

With marginal cirri, dorsoventrally flattened 12

1 2 Marginal cirri on both right and left sides, confluent posteriorly . SWEDMARKIA (p. 240)
Marginal cirri on either right or left sides 13

13 Marginal cirri on left, not planktonic CERTESIA(p.221)

Marginal cirri on right, planktonic CYATHAROIDES(p.243)

REVIEW OF EUPLOTIDAE 193

Genus DISCOCEPHALUS Ehrenberg, 1 828

Introduction

The genus Discocephalus was erected by Ehrenberg in Hemprich and Ehrenberg (1828) and
although his description and illustration of the type species D. rotatorius were crude, it was
clear that the organism had a distinctive discoid 'head' formed by a constriction at the
anterior end of the elongate oval body. Butschli (1889) expressed some doubt concerning the
observations of Ehrenberg (1831) but it was not until Kahl (1932), that Discocephalus was
adequately described. The latter description concerned an organism which Kahl (1932)
considered to be D. rotatorius Ehrenberg and of which he thought Polycoccon octangularis
Sauerbrey, 1928 to be a junior synonym. Later, however, Dragesco (1960) isolated an
organism from Roscoff which although identical to that described by Kahl (1932) was
different in several respects from D. rotatorius Ehrenberg. Dragesco (1960) therefore named
the species found at RoscoffZ). ehrenbergi and designated D. rotatorius Kahl to be its junior
synonym. However, Dragesco (1960) agreed that Polycoccon octangularis Sauerbrey was a
synonym of D. rotatorius Ehrenberg. In addition to the two species mentioned above two
others, D. grandis Dragesco, 1954 and D. minimus Dragesco, 1968, have been described.

There is a well developed AZM in all four of the above species which borders the small
ventral peristome on the left of the discoid 'head'. In one species, D. ehrenbergi, there are 5-7
large membranelle-like structures lying along the right border of the peristome which
Dragesco (1968) called 'pre-membranelles'. This character enables the diagnosis and
separation of D. ehrenbergi Dragesco from D. rotatorius Ehrenberg which lacks these
'membranelles'.

The cirral patterns on the ventral surface of Discocephalus differ greatly from those of
Euplotes and as their morphogenesis is yet to be published fully it is difficult to interpret
them adequately. Furthermore as the cirri vary considerably from species to species, it is
possible that Discocephalus is really a polyphyletic group. The present confusion in different
terms used for the same cirri by different authors can be illustrated by reference to 'marginal'
cirri. In D. rotatorius and D. ehrenbergi there are two 'marginal' cirri on the left body edge
just below the peristome. However, in D. grandis, Dragesco (1954) refers to the presence of
three rows of 'marginal' cirri which is more characteristic of members of the Oxytrichidae
rather than the Euplotidae. Furthermore, in D. minimus there is one row of cirri on the right
body edge called ventral cirri and one row on the left edge called 'marginal' cirri. Until
further morphogenetic information becomes available the present authors prefer to follow in
part the system used by Hartwig and Parker (1977) which distinguishes left, central and right
ventral cirri rather than to attempt to distinguish marginal from ventral rows simply on the
basis of their position on the ventral surface. However, it is preferable to call the most
posterior cirri, left and right caudal cirri, rather than left and right posterior 'marginals' as
used in Hartwig and Parker (1977). The dorsal surface of Discocephalus has received less
attention than that of either Euplotes (Curds, 1975) or Aspidisca (Wu & Curds, 1979) but
both Dragesco (1965) and Kahl (1932) have illustrated D. ehrenbergi with six kinetics on the
dorsal surface. Dorsal argyrome patterns as found in Euplotes and Aspidisca (Curds, 1975:
Wu & Curds, 1979) have yet to be described. This means that the four species must currently
be distinguished on the basis of their size, numbers and distribution of cirri, the presence or
absence of membrane-like structures on the right of the peristome and the nature of the
macronuclear apparatus. Corliss (1979) described this as a curious genus which he included
only 'tentatively' in the Euplotidae and indeed, the unique body shape, the cirral arrange-
ment and large number of macronuclear parts may well be considered sufficient for placing it
in a separate family.

Diagnosis of Discocephalus

Oval marine hypotrichs with an anterior constriction of the body which forms a discoid

194

C. R. CURDS & I. C. H. WU

'head' containing the peristome and AZM on the left. Ventrally there are 4-8 frontal, 5-1 1
transverse (including satellites) and variable numbers and arrangements of ventral cirri.
Posterio-dorsally there are 3-4 right caudal and 9-30 left caudal cirri. The size varies
between 50-200 um long and there are numerous macronuclei.

Key to the species of Discocephalus

\ With 2 left ventral cirri

With 7 to many left ventral cirri

2 With 5 transverse cirri but without 'pre-membranelles'.
With 8-9 transverse cirri and several 'pre-membranelles'

3 Large (200 urn), row of many (about 40) left ventral cirri
Small (50 urn), row of few (7-8) left ventral cirri .

2
3

D. rotatorius

D. ehrenbergi

D. grandis

D. minimus

Species descriptions

Discocephalus rotatorius Ehrenberg, 1828 in Hemprich and Ehrenberg
Polycoccon octangulus Sauerbrey, 1928

DESCRIPTION (Fig. 1). Medium sized (70-100 um long) marine species whose elongate, oval
body is typically discocephalic. There is a well developed AZM bordering the left of the
peristome area. The 7-8 frontal cirri are restricted to the anterior 'head' region. The ventral
cirri are in two groups: there are 2-4 on the right body edge and 2 on the left immediately
behind the peristome. There are 5 prominent transverse cirri. The caudal cirri are also in two
groups and arise dorso-laterally: on the right are 3-4 large prominent caudals and on the left

20yu

Fig. 1 Discocephalus rotatorius: (a, b) after Sauerbrey, 1928 (called Polycoccon octangulus); (c)
unpublished figure after Faure-Fremiet (in Dragesco, 1960).

REVIEW OF EUPLOTIDAE

195

is a row of many (12-20) smaller caudal cirri. The macronucleus is divided into many
randomly distributed spherical parts.

NOTES. The description is based on that of Sauerbrey (1928) and on the illustration given in
Dragesco (1960) but attributed to unpublished diagrams of Faure-Fremiet.

Discocephalus grandis Dragesco, 1954

DESCRIPTION (Fig. 2). Large (200 um long) marine species with an uncharacteristically large
number (120-150) of ventral cirri arranged in three longitudinal rows: one lies on the left
body edge and two on the right. There are 4 frontal cirri which are all located along
the right margin of the discoid 'head'. Immediately above the first of the long transverse cirri,
on the left, are two small 'satellite' transversal cirri. There are two small right caudal and
about 13 left caudal cirri. The macronucleus is divided into many (10-20) spherical parts
each being 3-6 um in diameter.

NOTE. This description is based on those of Dragesco (1954, 1960) who noted that the
species is very similar to Holosticha discocephalus Kahl.

Discocephalus ehrenbergi Dragesco, 1960
Discocephalus rotatorius Kahl, 1932 misidentification

Fig. 2 Discocep ''alus grandis, after Dragesco, 1 960.

196

C. R. CURDS & I. C. H. WU

DESCRIPTION (Fig. 3). This is a medium sized (90-120 um long) marine species. The presence
of 7-9 transverse cirri (with 1 or 2 'satellites', Fig. 3f-h) and 5-7 'pre-membranelles' on the
right of the peristome serve to distinguish it from the type species D. rotatorius Ehrenberg.
The AZM consists of 18-22 membranelles arranged along the left of the peristome and there
is an undulating membrane on the right. The 4-8 frontal cirri are of variable size and there
are 2 left ventral, 2 mid-ventral and 4 right ventral cirri. The caudal cirri are in two groups:
3-4 right caudal and 14-20 caudal cirri on the left. There are 6 dorsal kineties with only the
third from the right extending into the 'head' region (Dragesco, 1965). There is a large

30K

Fig. 3 Discocephalus ehrenbergi: (a, b) ventral and dorsal surfaces, after Dragesco, 1965; (c, d)
ventral and, dorsal surfaces, after Kahl, 1932 (called D. rotatorius); (e, 0 ventral surface and
variations in transverse cirral arrangement, after Dragesco, 1960.

REVIEW OF EUPLOTIDAE 197

number of spherical parts to the macronuclear apparatus which are scattered throughout the
body but apparently not in the 'head' region.

NOTES. This species was first described by Kahl (1932) as D. rotatorius Ehrenberg but was
renamed and redescribed by Dragesco (1960, 1965). Later Dragesco (1968) expressed doubts
about his conclusions and suggested that the species described as D. ehrenbergi in 1960 (Fig.
3e-h) might be a different species from that described in 1965 (Fig. 3a-b), although there was
insufficient information to be certain. The description above is based on that of Dragesco
(1965) but variations noted in other descriptions are included.

Discocephalus minimus Dragesco, 1968

DESCRIPTION. Discocephalus minimus (Fig. 4) is characterised by its small size (50-60 urn
long) and possession of left ventral cirri. The species has 7 frontal, 4-6 right ventral, 2 mid-
ventral and 7 left ventral cirri. There are 4 right caudal and 9-10 left caudal cirri. The
macronucleus is divided into relatively few (3-1 5) spherical parts.

lOyu

Fig. 4 Discocephalus minimus, after Dragesco, 1 968.

NOTES. The single description of this species is based on the observation of 5 individuals
(Dragesco, 1968) and there are no data on the dorsal aspect of this organism.

Genus DIOPHRYS Dujardin, 1841
Introduction

It was Dujardin (1841) who first briefly described an organism called Diophrys marina and
defined the genus Diophrys as having a discoid shape with groups of long 'cilia' at the two
extremities of the body which was without a mouth. Later Stein (18590) stated that both D.
marina and the earlier Stylonychia appendiculata Ehrenberg, 1838 were synonyms of

198 C. R. CURDS & I. C. H. WU

Styloplotes appendiculatus Stein, 1859 (see Stein 1859a) which he characterised by the
presence of three large right caudal cirri. Biitschli (1889) recognised Diophrys as a distinct
genus and his list of synonyms included certain species of the genera, Stylonychia Ehrenberg,
Ploesconia Dujardin, Euplotes Claparede & Lachmann, Schizopus Claparede & Lachmann,
Styloplotes Stein, Styloplotes Quennestedt, Styloplotes Fresenius, Styloplotes Rees,
Styloplotes Fabre-Domergue, and Styloplotes Andrusova. Although Biitschli (1889) stated
that there were two species in the genus, he only illustrated Diophrys (Styloplotes) grandis
Rees, 1 88 1 and failed to mention D. appendiculata. Over the next few years the combination
D. appendiculata was used occasionally, for example, by Wallengren (1901) and by Calkins
(1902) who established the combination Diophrys (Styloplotes) appendiculatus Stein.
However, it was Kahl (1932) who first traced the taxonomic history of the species correctly.
Borror (1972) recently listed eleven species of the genus with their synonyms and he
designated Diophrys scutum (Dujardin, 1841) Kahl, 1932 the type species and listed D.
marina as a synonym of D. appendiculata (Ehrenberg) Kahl. In view of the evidence given
above, the present authors are of the opinion that Diophrys (Stylonychia) appendiculata
(Ehrenberg, 1838) Kahl, 1932 is the correct name and authority for the type species of the
genus Diophrys.

Kahl (1932) defined the genus Diophrys as those members of the family Euplotidae with
conspicuous sturdy transverse cirri and a single group of three large caudal cirri. In addition
to D. appendiculata, Kahl (1932) described, and gave keys, to three other species, Diophrys
(Ploesconia) scutum (Dujardin, 1841) Kahl, 1932; Diophrys hystrix Buddenbrock 1920 and
Diophrys irmgard Mansfeld, 1923. Of the eleven species listed by Borror (1972) the present
authors accept ten nominal species. D. tetramacronucleata Kattar, 1970 and D.
multinucleata Hartwig, 1973 are two later additions to the genus, characterised by their
possession of four and over twenty macron uclei respectively. The authors accept the latter as
a distinct species but suspect that the former is a synonym of D. appendiculata.

Two of the species, D. appendiculata and D. scutum, have been described by many authors
over the past century but most of the other species are relatively recent additions. In most
cases there are rather few data on the extent of intraspecific variation that might be found in
potentially useful diagnostic structures. Even so, it was thought worthwhile to present a
summary of the data that are available and to discuss the possible diagnostic importance of
the various morphological features.

(a) Shape. The typical body shape of Diophrys is an ovoid in which there is often a posterior
right lateral indentation where the right caudal cirri are located. The anterior of D. hystrix is
particularly truncate and the body of D. kahli is elongate. The dorsal surface of Diophrys is
generally smooth, but in D. irmgard it is described with a 'trapeziform elevation'
(Mansfeld, 1923). These variations are apparently distinctive although the keys here do not
rely upon them for identification of these species.

(b) Size. Most Diophrys species are between 50 and 120 um long. D. scutum at 1 50-200 (j.m
long is the largest and D. hystrix at 30-40 um long is the smallest. Size variation within
species appears to be small (Hartwig, 1973) so the size differences between D. hystrix, D.
scutum and D. appendiculata (50-100 um long) are likely to be of diagnostic value.

(c) Adoral zone of membranelles (AZM). Diophrys has a wide peristome which extends a
third to two-thirds down the body length. On the right of the peristome there is a large, wide
undulating membrane. On the left, there is a well-developed AZM which continues
anteriorly over onto the dorsal surface: in some species it can return to the ventral surface
down the right side of the body. Borror (1965a) stated that statistical analysis showed that the
length of the right portion of the AZM in D. scutum was significantly longer from that of D.
peloetes. He noted that this 'terminal portion' of the AZM in D. scutum was 0-4 the body
length but only 0-3 the body length in D, peloetes. The present authors would not
recommend species recognition on such a small difference as this without resort to statistical
morphometric analysis but it is a useful feature for distinguishing between certain species.

REVIEW OF EUPLOTIDAE

199

For example, in D. appendiculata the AZM hardly extends onto the right of the body while
in D. scutum it extends almost to the central region. Rees (1883) and Kahl (1932) also
consider this right extension of the AZM to be an important diagnostic feature by which they
identified Styloplotes quennerstedti and D. scutum respectively.

(d) Cirri. The type species, D. appendiculata, has 7-8 fronto ventral, 5 transverse, 1-3 left
marginal and 3 right caudal cirri. The frontoventral cirri are arranged in two distinct groups,
with 5 in the anterior right frontal group and 2-3 in the ventral group, often much smaller
than the frontal cirri, lying in close proximity to the first transverse cirrus on the right. This
distribution pattern is seen in all species but D. hystrix, D. irmgard and D. kahli have 9-10
frontoventrals in groups of 7 frontals and 2-3 ventrals which the authors consider to be of
diagnostic importance. Some authors are in agreement with this others are not. For example,
Agamaliev (1967) established a new species D. scutoides which differs from D. scutum only
in having five instead of seven frontoventral cirri. However, Borror (1963) identified an
organism as D. irmgard even though it possessed only five frontoventrals rather than the nine
in Mansfeld's (1923) original description. Borror (1963) neither established the organism as a
new species nor did he suggest the cirral difference to be due to intraspecific variation. The
morphogenesis of cirri in D. appendiculata was described by Wallengren (1901). The
frontoventral-transverse cirri arise from six streaks of kinetosomes as in Euplotes, with the
I/I , 11/2, II/3, HI/2 and IV/2 cirri forming the frontals: V/2 and VI/2 the ventrals and II-VI/1
the transversals (Fig. 5).

The transverse cirri of Diophrys are noticeably larger than those of Euplotes. There are
almost invariably five transverse cirri but there are only four in D. irmgard and D.
multinucleata. The presence of large, sickle-shaped, dorso-laterally attached right caudal
cirri is a characteristic feature of the genus Diophrys. During morphogenesis, these cirri arise
from basal bodies at the posterior ends of the ciliary rows on the right of the dorsal surface
(Borror, 1972). Most of the species described have three of these cirri but D. quadricaudatus
Agamaliev, 1967 has four and D. kahli Dragesco, 1963 has only one. Intraspecific variation
in the number of these cirri has not yet been reported and so it is thought that this might be a
useful diagnostic character. In most species, the left marginal cirri are located just posterior

Fig. 5 Arrangement and numbering of cirral streaks in Diophrys appendiculata, after

Wallengren, 1901.

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C. R. CURDS & I.C. H. WU

to the peristome, but in D. irmgard, D. kahli and D. multimicronucleata, they are in the
'caudal position' as are those in Euplotes and Uronychia. Hartwig (1974) believed that the
positioning of these cirri in these three species was sufficient to constitute a separate genus.
While the present authors agree that the caudal positioning of the left marginal cirri appears
to be a significant character apparently associated with the presence of only four transverse
cirri, they hesitate to erect a new genus on this alone. Mansfeld (1923) and Kahl (1932)
distinguished D. irmgard from other species, not by the position of the left marginal cirri but
by their number. Although most species have two left marginal cirri and D. irmgard has
three, variation between 1-3 has been observed in D. appendiculata.

(e) Nuclear features. The most commonly found nuclear arrangement in Diophrys is two
macronuclei and 2-6 micronuclei. Exceptions to this include D. quadricaudatus, D.
tetramacronudeata and D. multinucleata which have three, four and over 20 macronuclei
respectively, with the diagnosis of the latter two species resting heavily on this feature. The
macronuclei may be rod-shaped, ovoid or moniliform.

Fig. 6 Nuclear arrangement in Diophrys: (a) Diophrys magnus, after Raikov & Kovaleva, 1968;
(b-d) Diophrys scutoides, after Agamaliev, 1967; (c) Diophrys quadricaudatus, after Agamaliev,
1967; (e, 0 Diophrys hystrix, after Buddenbrock, 1920.

Raikov and Kovaleva (1968) separated D. magnus from D. scutum principally on the basis
of its macronuclei being moniliform, however they are similar to those of D. scutum and
other species which are often shown to be slightly nodular (Fig. 6a-c). Here D. magnus and
D. scutum are therefore regarded to be synonymous.

Summers (1935) described the reorganisation and division of the macronuclei of D.
scutum, misidentified as D. appendiculata. He noted (Fig. 7) that in the normal resting stage,
the species possesses two macronuclei without a visible strand between them and a variable
number of micronuclei. He observed that fragmentation of the reorganised parts of the
macronuclei was not uncommon but 'fragments of the macronuclei have never been found
free in the cytoplasm after the several parts fuse to form the rod-like mass'. One cannot be
certain if the tripartite macronuclear structure of D. quadricaudatus (Fig. 6d) is the result of
fragmentation or if it is the true resting stage, but it is likely that the sausage-shaped nucleus
which Buddenbrock (1920) described in certain specimens of D. hystrix to be a divisional
stage in the normally ovoid macronuclei (Fig. 6e).

REVIEW OF EUPLOTIDAE

201

Fig. 7 Division of the macronucleus of Diophrys scutum, after Summers, 1935 (called D.
appendiculatd): (a) nucleus at rest; (b) first appearance of a reorganisation band at the outer pole
of the posterior macronucleus; (c) reorganisation bands about to disappear at inner poles of the
macronuclei; (d) fusion of the macronuclei; (e) after fusion; (0 macronucleus beginning to divide;
(g) macronuclei completely divided just before daughter cells separate.

Kisselbach (1936) also illustrated various stages in the nuclear development of D.
appendiculata (Fig. 8a-e) one of which shows a quadripartite stage similar to that illustrated
by Kattar (1970) in D. tetramacronucleata (Fig. 8f, g). In view of this D. tetramacronucleata
should be strongly suspected as being a synonym of the type species. However, since one
illustration by Kattar (1970) and another by Hartwig (1974) show the four ovoid
macronuclei to be completely distinct (Fig. 8g) the species has been provisionally included
here awaiting further data. As mentioned above, there are commonly 2-6 micronuclei in
Diophrys. Borror (19650) accorded little significance to this feature and referred to Ito (1963)
who stated that macronuclei may vary considerably in number within a species.

(/) Dorsal silver-line system. Borror (19650) pointed out that few workers had mentioned the
dorsal ciliature in Diophrys species descriptions and observed that Kahl (1932) was the first
to note the presence of five rows of short cilia in D. scutum. Using the Chatton-Lwoff(1930)
technique, Borror (19650) was able to show that '. . . the kinetosomes in the dorsal rows of
Diophrys behave during cell division in a manner similar to the behavior of the dorsal
kinetosomes in Euplotes, hence the proter and opisthe usually have the same number of
rows. Within a population, with practically no exceptions, all members of the genus present
have the same number of rows of cilia dorsally, and this is apparently not related with body
size.'

202

C. R. CURDS & I.C. H. WU

Several authors have used the number of dorsal kinetics as a diagnostic character (Borror,
19650, b: Agamaliev, 1967: Raikov & Kovaleva, 1968). However, the dorsal silver-line
systems of other species including D. hystrix, D. irmgard, D. kahli, D. tetramacronudeata
and D. multinucleata still remain to be described. For this reason the key here only
distinguishes between D. oligothrix and D. peloetes on this character. All dorsal argyromes
that have been described so far consist of a meshwork pattern and are therefore of little value
for specific identification.

Fig. 8

20yur

Nuclear arrangement in Diophrys: (a-e) Diophrys appendiculata, after Kisselbach, 1936;
(f, g) Diophrys tetramacronudeata, after Kattar, 1970.

Diagnosis of Diophrys

Marine hypotrichs 30-200 um in length. Ovoid body usually with prominent right
posterio-lateral concavity from which arise three large sickle-shaped right caudal cirri. There
are 5-10 fronto ventral, 4-6 transverse and usually 2-3 left marginal cirri. There are often
two elongate, sometimes nodular, macronuclei but in some species there may be four or over
twenty macronuclei. There is a variable number of micronuclei. The dorsal silver-line
system consists of 4-8 dorsolateral kinetics and a mesh-like argyrome.

Key to the species of Diophrys

1 With 5 frontoventral cirri

With more than 5 frontoventral cirri

2 With 7-8 frontoventral cirri

With 9- 10 frontoventral cirri

3 With 4 right caudal cirri

With 3 right caudal cirri

4 With 1-3 left marginal cirri

Without left marginal cirri

5 With 2 macronuclei

With 4 or more macronuclei

6 With 5-6 dorsolateral kinetics

With less than 5 or greater than 6 dorsolateral kinetics .

7 AZM extends almost to centre of right border, 1 50-200 um long.
AZM hardly extends at all down right border, 50- 1 00 um long .

8 With 4 dorsolateral kinetics

With 8 dorsolateral kinetics

I), scutoides

. . 2

. . 3

. . 10

D. quadricirratus

. . 4

. . 5

D. salina

. . 6

D. scutum

D. appendiculata

D. oligothrix

D. peloetes

REVIEW OF EUPLOTIDAE 203

9 With 4 macronuclei D. tetramacronucleata

With 20 or more macronuclei D. multinucleata

10 With 2 left marginal cirri posterior to the peristome, 30-40 urn long .... D. hystrix
Left marginal cirri in the 'caudal' position, 80-100 um long. ....... 11

1 1 With 1 right caudal and 2 left marginal/caudal cirri D. kahli

With 3 right caudal and 3 left marginal/caudal cirri D. irmgard

Species descriptions

Diophrys appendiculata (Ehrenberg, 1838)Kahl, 1932

Stylonychia appendiculata Ehrenberg, 1838

Diophrys marina Dujardin, 1 84 1

Schizopus norwegicus Claparede & Lachmann, 1858

Styloplotes appendiculatus Stein, 1 859

Styloplotes fresenii Rees, 1883

Styloplotes appendiculatus var. pontica Andrusova, 1 886

Planiplotes wagneri Andrusova, 1 886

Diophrys appendiculatus (Stein, 18 59) Calkins, 1902

DESCRIPTION (Figs 9, 10). This, the type species of the genus, is 50-100 (im long. The body
shape is typically ovoid with the characteristic lateral concavity at the posterior where the
three sickle-shaped right caudal cirri arise. There are 7-8 frontoventral cirri - 5 anterior and
2-3 close to the transversals, 5 transverse and 1-3 left marginal cirri. The AZM extends
down half to two-thirds of the length of the body on the left but hardly at all on the right. The
two macronuclei are usually elongate to ovoid and may be smooth or nodular. There are 2-4
micronuclei and 5-6 dorsolateral kinetics each carrying 6-10 cilia.

NOTES. Some of the nomenclatural history of this species has already been outlined in the
introduction to the genus. Kahl (1932) transferred Stylonychia appendiculata Ehrenberg,
1838 to the genus Diophrys and redescribed the species. However, he made no reference to
the fact that Stein (1859#) had already erroneously redefined the species as Styloplotes
appendiculatus which combination was subsequently used by many workers (Fresenius,
1865: Quennerstedt, 1867: Kent, 1881: Rees, 1883: Fabre-Domergue, 1885). Stein (18590)
suggested that Ehrenberg (1838) had overlooked the frontoventral cirri and suggested that
Schizopus norwegicus Claparede & Lachmann, 1858 was probably a synonym, even though
Claparede & Lachmann (1858) had distinguished their species from Stylonychia
appendiculata Ehrenberg by the absence of marginal cirri. It seems likely that the two left
marginal cirri were mistaken identified to be satellite transverse cirri. Calkins (1902) later
transferred Styloplotes appendiculatus Stein to the genus Diophrys.

Rees (1883) briefly 'described a species of Styloplotes which he stated was the same as
Styloplotes appendiculatus Stein as described by Fresenius (1865) which he (Rees, 1883)
proceeded to call Styloplotes fresenii. Earlier Rees (1881) had described the new species
Styloplotes grandis but later (Rees, 1883) concluded that it was identical to Styloplotes
norwegicus Quennerstedt, 1867 which he then erroneously called Styloplotes quennerstedti.
In the present authors, opinion, Quennerstedt (1867) was mistaken in making Styloplotes
norwegicus Quennerstedt a synonym of Schizopus norwegicus Claparede & Lachmann. It is
here considered that the former species is a synonym of D. scutum because of the extent to
which the AZM is developed on the right side of the body. Rees (1883) also used this
character to distinguish Styloplotes quennerstedti, a synonym of D. scutum, from Styloplotes
fresnii, a synonym of D. appendiculata.

Diophrys scutum (Dujardin, 1841) Kahl, 1932

Ploesconia scutum Dujardin, 1841 (in part)

204

C. R. CURDS & I.C. H. WU

15;urn

* •* » " «-J--1.9

jfa. - * •:- •: fto i>
*-% • feiS-VS*!'
><V^ V^-^'V-1

• ^•-ni^.s

Fig. 9 Diophrys appendiculata: (a) after Ehrenberg, 1838 (called Stylonychia appendiculatd);
(b, c) after Claparede & Lachmann, 1 858 (called Schizopus norwegicus); (d, e) after Stein, 1 859a
(called Styloplotes appendiculatus); (0 after Fresenius, 1865 (called Styloplotes appendiculatus);
(g) after Calkins, 1902 (called D. appendiculatm; (h) after Kahl, 1932; (i,j) after Pierantoni,
1909; (k) after Andrusova, 1886 (called Styloplotes appendiculatm var. pontica; (1) after
Andrusova, 1886 (called Planiplotes wagneri).

205

Fig. 10 Diophrys appendiculata, after Borror, 1963: (a) ventral surface; (b) dorsal surface; (c)

nuclei.

20 um

20 urn

Fig. 11 Diophrys scutum: (a) after Dujardin, 1841 (called Ploesconia scutum); (b) after Butschli,
1 889 (called Diophrys grandis); (c) after Dragesco, 1963; (d-f) ventral surface, dorsal surface, and
nuclei, after Borror. 1965a.

206

C. R. CURDS & I. C. H. WU

Styloplotes norwegicus Quennerstedt, 1 867
Styloplotes grand is Rees, 1881
Styloplotes quennerstedti Rees, 1 883
Diophrys grandis Butschli, 1889
Diophrys magnus Raikov & Kovaleva, 1968
Diophrys kasymovi Agamaliev, 1 97 1

DESCRIPTION (Figs 11, 12). This is the largest species (150-200 urn long) of the genus so far
described. It may be distinguished from the type species, D. appendiculata, by its size and by
the AZM which extends to the central body region on the right side. The body shape is ovoid
with an indentation in the posterior right. The dorsal surface is smooth and arched. There
are 3 large sickle-shaped right caudal cirri, 7-8 fronto ventral, 5 transverse and 2 left marginal
cirri. The two elongate macronuclei may be curved, nodular or moniliform and are
accompanied by up to six micronuclei. The dorsal silver-line system consists of 5-6
dorsolateral kinetics interspersed with mesh-like argyromes.

Fig. 12. Diophrys scutum: (a, b) ventral and dorsal surfaces with section showing argyromes, after
Agamaliev, 1968; (c) after Raikov & Kovaleva, 1968 (called D. magnus); (d, 0 ventral argyrome,
nuclei and dorsal argyrome after Agamaliev, 1 97 1 (called D. kasymovi).

REVIEW OF EUPLOTIDAE

207

NOTES. Claparede & Lachmann (1858) and Stein (\S59a) believed that the three illustrations
of Ploesconia scutum by Dujardin (1841) were of two different species. Claparede &
Lachmann (1858) thought that one represented a Euplotes species whereas Stein (1859a)
considered it to be Styloplotes appendiculatus Stein. The present authors doubt both of these
opinions but agree with Kahl (1932) who identified the species as Diophrys scutum and
considered the AZM originating in the middle of the right border to be an important
diagnostic feature. It is mainly by this character that D. scutum can be distinguished from D.
appendiculata. Raikov and Kovaleva (1968) distinguished D. magnus from D. scutum by the
difference in the shapes of their macronuclei which is not a significant feature. The recent
addition D. kasymovi Agamaliev, 1971 has been included here in spite of it being rather
small for this species.

Fig. 13 Diophrys hystrix, after Buddenbrock, 1 920: (a) ventral surface; (b, c) nuclear features.

Diophrys hystrix Buddenbrock, 1920

DESCRIPTION (Fig. 1 3). Diophrys hystrix is a small (30^0 urn long) species. The body outline
is generally oval but it is truncated anteriorly and there is the usual concavity on the
posterior right accommodating three large sickle-shaped right caudal cirri. The dorsal
surface is strongly arched. The ten frontoventral cirri are arranged in two distinct groups
with 7 'frontals' at the anterior on the right of the peristome and 3 'ventrals' near the
transverse cirri. One of the 'ventrals' is adjacent and similar in size to the transversals, but it
points in the opposite direction and is used in the creeping movements of the animal. There
are 4 long transverse cirri and 2 small left marginal cirri located just behind the peristome.
There are two ovoid macronuclei.

NOTES. Kahl (1932) gave an almost identical description and illustration of this species as in
Buddenbrock's (1920) original. Kattar (1970) identified a small (35-40 urn) species with two
ovoid macronuclei as D. hystrix but this is a dubious identification since the author gave an
inadequate description and the illustration was of a different shape and cirral number to that
of Buddenbrock (1920).

Diophrys irmgard Mansfeld, 1 923

DESCRIPTION (Fig. 14). This is a medium sized (75-135 urn long) marine species. The body
shape is characteristic, being broadly oval in outline but tending to be rectangular. The wide
peristome is approximately half the body length and there is a prominent undulating

208

C. R. CURDS & I. C. H. WU

Fig. 14 Diophrys irmgard: (a, b) after Mansfeld, 1923; (c, d) after Kahl, 1932; (e) after Dragesco,

1 963 ;(f) after Borror, 1963.

membrane on the right. The AZM bordering its left edge curves around the anterior end but
only just extends to the right side of the body. There are 3 right caudal, 9 frontoventral, 4-5
transverse and 3 left marginal cirri. The two ovoid macronuclei are 8 urn in diameter and
each is associated with a micronucleus.

NOTES. This species may be distinguished from the type species, D. appendiculata, by the
presence of 9 instead of 7 frontoventral cirri and because the left marginal cirri are in the
'caudal' position. The shape of its body is consistently observed to be widely oval,
rectangular and lacks the posterior lateral concavity on the right which is usually charac-

REVIEW OF EUPLOTIDAE

209

teristic of the genus. Additionally, the right caudal cirri are attached dorsally like those of
Uronychia. Horror (1963) described an organism which he called D. irmgard but as it had
only 5 frontoventral cirri perhaps future studies will show this to be a separate species.

Diophrys salina Ruinen, 1938

DESCRIPTION (Fig. 1 5). This is a small (3CMO um long) species. The outline shape of the
body is characteristically oval without any obvious lateral concavities but there is a posterior
indentation where the 3 large caudal cirri arise. The dorsal surface is strongly convex, but the
ventral surface is flattened. The peristome region extends to the centre of the body, with an
AZM on the left and a well developed undulating membrane on the right. The frontoventral
cirri are arranged in two groups with 4 right anterior 'frontals' and 4 'ventrals' situated
immediately behind, and to the right of, the peristome. There are no left marginal cirri. Five
transverse cirri lie between the caudal and 'ventral' cirri. The original description did not
include any details concerning the nuclear apparatus. Feeds on diatoms, algae and bacteria.

Fig. 15 Diophrys salina: (a, b) ventral surface and lateral view, after Ruinen, 1 938.

Diophrys kahli Dragesco, 1 963

DESCRIPTION (Fig. 16). This species is about 80 um long, the body is elongate with a short
posterior narrowed tail region. The peristome is small, bordered on the right by a well
developed undulating membrane and on the left by a small AZM. The frontoventral cirri
consist of a group of 7 long 'frontals' and 2 small 'ventrals'. The 5 transverse cirri are long,
the 2 left marginal cirri are in the 'caudal' position and there is only one right caudal cirrus.
The two oval macronuclei are connected by a nuclear membrane and there are 4-6
micronuclei. A few cilia have been observed along the left border of the animal.

NOTES. Dragesco (1963) identified an organism that he considered to be identical to one
incompletely studied by Kahl (1932) which he called D. kahli. Untypically, the body of this
species is rather elongate and its left marginal cirri emerge caudally instead of immediately
posterior to the peristome. Hartwig (1974) grouped this species with D. irmgard and D.

210

C. R. CURDS & I.C. H. WU

Fig. 16 Diophrys kahli: (a, b) ventral surface and dorsal plaques, after Dragesco, 1963; (c) dorsal
surface, after Kahl, 1932 (called an 'incompletely studied Diophrys species').

multinucleata because of this latter feature. In contrast to other species in the genus, D. kahli
has only one right caudal cirrus, its peristome is rather small and the AZM is under-
developed. Dragesco (1963) described the presence of small oval plaques on the dorsal
surface (Fig. 14b) which he suspected to be 'protrichocysts'.

Diophrys oligothrix Borror, 1 965

DESCRIPTION (Fig. 17). Diophrys oligothrix is a medium sized (79-106 urn long), ovoid
species. The concavity at the posterior right edge, so typical of the genus, is here incon-
spicuous and the dorsal surface smooth. The AZM bordering the left edge of the large
peristome continues dorsally along the anterior region to the right side of the body. The
ciliature and nuclear features are also typical of the genus, there are 7 fronto ventral, 5
transverse, 2 left marginal and 3 right caudal cirri. The two irregular, elongate macronuclei
are usually accompanied by four micronuclei. The silver-line system consists of 3 dorsal
kinetics, one lateral kinety on the right and a fine mesh-like argyrome. The dorsal kineties
bear, from left to right, 13-20, 16-24, 12-18 cilia and the ventral kinety 9-13 cilia.

NOTE. This species is distinguished from D. scutum on the basis of its different number of
kineties.

Diophrys peloetes Borror, 1965

DESCRIPTION (Fig. 18). D. peloetes is a medium sized (95-135 urn long) species typical of the
genus. It has a wide peristome which is about two-thirds of the body length, bordered by a
well developed AZM on the left and an undulating membrane on the right. The AZM travels
along the anterior dorsal edge onto the right side of the body where it extends about 3/10 of
the body length. There are 3 prominent right caudal cirri, 5 long transverse, 7 frontoventral
and 2 left marginal cirri. The two macronuclei are elongate. There are 8 dorsolateral

REVIEW OF EUPLOTIDAE

211

Fig. 17 Diophrys oligothrix, after Borror, 19656: (a) ventral surface; (b) dorsal surface; (c) frontal

section showing nuclei.

kinetics, each bearing 6-17 cilia. The number of kinetics distinguishes this species from D.
scutum which has only five.

NOTES. Borror (1965a) established D. peloetes after a morphometric comparison with D.
scutum. He stated that the new species was 'extremely similar to D. scutum except for having
eight dorsal rows of cilia instead of five, having fewer cilia per row, and having a significantly
shorter AZM'. He also pointed out that he had identified it incorrectly as D. scutum in an
earlier study (Borror, 1963).

Diophrys quadricaudatus Agamaliev, 1967

DESCRIPTION (Fig. 19). This is a medium sized (100-1 10 urn long) species, characterised by
the presence of 4 right caudal cirri arising from a particularly prominent concavity on the
posterior right of an otherwise oval body. The wide peristome is about 48 um long and on its
right there is a conspicuous undulating membrane. The AZM is composed of 50-60
membranelles which extend forward over to the right side of the body. There are 7
fron to ventral, 5 transverse, and 3 left marginal cirri. The dorsal silver-line system consists of
5 or 6 dorsolateral kinetics and a finely-meshed dorsal argyrome. There are two anterior and
one posterior macronuclei.

212

C. R. CURDS & I. C. H. WU

Fig. 18 Diophrys peloetes: (a, b) ventral and dorsal surfaces, after Borror, 1963 (called D.
scutum); (c-e) ventral and dorsal silver-line systems, and nuclei, after Borror, 1965a.

NOTES. Agamaliev (1967) considered the presence of four right caudal cirri and three
macronuclei to be the diagnostic features of this species. The uneven number of macron uclei
is rather strange and could perhaps represent an interdivisional state.

Diophrys scutoides Agamaliev, 1967

DESCRIPTION (Fig. 20). D. scutoides is 1 10-120 urn long. The body is oval with a prominent
concavity on the posterior right edge. The AZM of 75-80 membranelles borders the left edge
of a wide peristome and continues along the anterior edge to extend a third of the body length

REVIEW OF EUPLOTIDAE

213

20yum

Fig. 19 Diophrys quadricaudatus, after Agamaliev, 1967: (a) ventral surface of living cell (b-d)
stained ventral surface, dorsal surface and nuclei.

down the right side. There are 3 right caudal, 5 transverse and 2 left marginal cirri but only 5
frontoventral cirri. The two elongate macronuclei are nodular and are accompanied by three
micronuclei. The silver-line system consists of 5 dorsolateral kinetics with mesh-like dorsal
and ventral argyromes.

214

C. R. CURDS & I. C. H. WU

Fig. 20 Diophrys scutoides, after Agamaliev, 1967: (a) ventral surface; (b) dorsal surface; (c, d)

ventral and dorsal argyromes.

NOTES. Agamaliev (1967) described this species from the Caspian Sea. Apart from being
slightly smaller in size, it differs from D. scutum in having five instead of seven frontoventral
cirri.

Diophrys tetramacronucleata Kattar, 1970

DESCRIPTION (Fig. 21). This is a small (55-65 urn long) species. The body is oval except for
the concavity at the posterior right edge. The AZM consists of about 36 membranelles which
extend about halfway down the body on the left but hardly at all on the right. There are 7
frontoventral, 5 transverse, 2 left marginal and 3 right caudal cirri. There are 5 dorsolateral
kinetics and 4 ovoid macronuclei.

NOTES. The original description of this species was brief and only the presence of four
macronuclei distinguished it from the type species. Although it is suspected that Kattar
(1970) described an interdivisional specimen, it is provisionally included here as a nominal
species. Kattar (1970) stated that protargol impregnation showed the presence of three
median and two dorsolateral kinetics he provided no diagram of these structures. The

REVIEW OF EUPLOTIDAE

215

Fig. 21 Diophrys tetramacronucleata, after Kattar, 1 970: (a) ventral surface; (b) nuclei.

redescription and photographs of this species by Hartwig (1974) are also incomplete
although the presence of four macronuclei was clearly demonstrated.

Diophrys multinucleata Hartwig, 1973

DESCRIPTION (Fig. 22). D. multinucleata is a medium sized (76-11 Sum long) highly
thigmotactic species. The body is oval to rectangular in outline with the dorsal surface being
arched and the ventral surface flattened. There is a small but distinct projection on the
anterior right corner of the body. The peristome is about two-thirds of the body length. The
AZM consists of about 30 membranelles lying along the left of the peristome and a few larger
membranelles along the anterior edge of the body. The frontoventral cirri are arranged in
two distinct groups: the 5-6 large 'frontals' are in the anterior and the two very small
'ventrals' lie close to the transverse cirri. There are 4 long transverse, 3 right caudal and 3 left
marginal/caudal cirri. There are at least 20 macronuclei present.

NOTES. This species is characterised by the presence of over twenty macronuclei which is
unique in the genus, otherwise it is similar to D. irmgard in cirral arrangement, particularly
in the caudal positioning of the left marginal cirri which Hartwig (1973, 1974) considered to
be a feature of diagnostic importance.

Genus URONYCHIA Stein, 1859

Introduction

Stein (1859#, 18596) established and described the genus Uronychia and transferred
Trichoda transfuga Muller, 1786 to the genus as the type species. Between 1901 and 1928,
five new species were described and Kahl (1932) included a key to them in his classical
compendium. Since then only one addition, Uronychia bivalvorum Fenchel, 1965, has been

216

C. R. CURDS & I.C. H. WU

Fig. 22 Diophrys multinucleata, after Hartwig, 1973: (a) dorsal surface; (b) ventral surface

showing nuclei.

made which he found in the mantle cavity of certain lamellibranch molluscs. Uronychia is
characterised by its enormous peristome region occupying half of the ventral surface with
conspicuous peristomial membranes, the three posterior groups of large cirri, the apparent
absence of frontoventral cirri and by its rapid backward motion (Bullington, 1940). How-
ever, there are few features which clearly distinguish the described species from one another.
Many of the features used in the past are variable so that here only four nominal species are
recognised.

(a) Shape. The typical Uronychia body is oval. Dorsal ribs, ridges or striations are often
mentioned in descriptions but there are few data on the variability of these structures.
Ventrally, there are two large posterior cavities which accommodate the transverse and left
marginal cirri. In general, the right caudal cirri of Uronychia are attached more dorsally than
those in Diophrys, so the oval body outline is without the dorsolateral concavity at the
posterior right which is characteristic of the latter genus. However, Buddenbrock (1920)
described U. heinrothi with an 'Ausschnitt' (notch) on the posterior right edge which can
make the posterior border S-shaped. Similarly, Taylor (1928) described an 'uncinus' on U.
uncinata which he stated apparently owes its origin in part to an attenuation of the remnant
which holds proter to opisthe during the final stages of division.

It seems likely that the 'Ausschnitt' and 'uncinus' are the same structure and as
Buddenbrock (1920) noted that it was variable in extent and absent from some individuals
then it cannot be used as a reliable diagnostic character. Indeed if it is formed during division
then it could only be present in the proter of a dividing cell.

(b) Size. The distinctive sizes of U. magna and U. setigera are here considered to be

REVIEW OF EUPLOTIDAE

217

diagnostically significant. The former at 450 um long is the largest species so far described in
the family Euplotidae, and the latter at 40-50 jim long is the smallest Uronychia species. The
sizes of the remaining species fall within the range of 70-250 um long. The size of the type
species U. transfuga has been noted to vary between 50-1 50 um long (Kahl, 1932) but
Bullington (1940) separated U. heinrothi from U. transfuga by the larger size (129-264 um
long) of the species he observed. However, Buddenbrock (1920) described U. heinrothi as
having the range 70-250 urn in length. It is apparent that the size variation of these two
species is great and their ranges overlap. Since there are no other significant distinguishing
features, these two species are here regarded as being synonymous.

(c) Adoral Zone of Membranelles. The ventral surface of Uronychia is dominated by an
enormous peristome with conspicuous membranelles and membranes. Unlike the rest of the
Euplotidae, the AZM of Uronychia consists of large membranelles along the anterior of the
body and 4-5 smaller paroral membranelles at the posterior left of the peristome and there
are undulating membranes along both sides of the peristome. Fenchel (1965) was of the
opinion that it was the fusion of the adoral membranelles which forms the membrane along
the left peristomial border. These peristomial membranes and membranelles may be
observed to be closed over the peristome region or spread out and wing-like. The paroral
membranes are often found in a pocket-like invagination of the peristomial wall.

Buddenbrock (1920) described the presence of two large peristomial membranes in U.
heinrothi but these appear to be split into five parts in one of his diagrams. Bullington (1940)
observed four peristomial membranes on his specimens of U. heinrothi plus another large
membrane close to the posterior right edge of the body. This marginal membrane has been
described only on this occasion so it has not been used here as a diagnostic character.
Although the peristomial membranes of U. heinrothi appear to be larger and more numerous
than has been observed in U. transfuga, it is not considered to be a reliable character. On the
other hand, Calkins (1902) described 'flagella-like' cirri in the peristome of U. setigera which
have subsequently been noted by other authors (Buddenbrock, 1920; Young, 1922; Kahl,
1932; Kattar, 1970). This feature is apparently distinctive and consistent and is therefore
useful in the identification of U. setigera.

Fig. 23 Arrangement and numbering of cirral streaks in Uronychia transfuga, after Wallengren,

1901.

218

C. R. CURDS & I.C. H. WU

(d) Cirri. One of the most distinctive generic features of Uronychia is the apparent absence of
frontoventral cirri. Wallengren (1901) studied cirral morphogenesis in U. transfuga and was
first to number the cirral streaks (Fig. 23). He found that there was a small residuum of cirral
elements I/I, II/2 and 111/2 grouped closely together at the anterior right near the adoral
membranelles which he described as membranous cirri. Young (1922) noted these in three
Uronychia species and described them as cirri-like membranelles, but it was Buddenbrock
(1920) who illustrated three similar small cirrus-like structures at the anterior left as well as
on the right. Wallengren (1901) showed that the cirri V/2 and VI/2 which form the 'ventrals'
in Euplotes and Diophrys lie among the transversals in U. transfuga and they appear like
'satellites' in this group of cirri. These cirri have not yet been observed by other authors but
Buddenbrock (1920), Young (1922) and Taylor (1928) described the presence of one slender
cirrus at the right of the transversals in U. setigera, U. heinrothi and U. uncinata.

All species of Uronychia have 4 or 5 transverse cirri. Young (1922) considered the
possession of four transversals in U. binucleata to be a specific character even though he
recorded that the number of transversals in U. transfuga varied between 4 and 5. To the left
of the ventral cavity from which the transversals emerge, there is another cavity which
accommodates the two enormous left marginal cirri with a variable number of small cirri or
cilia. The right caudal cirri emerge dorsally on the posterior right and are invariably sickle-
shaped. All of the described species have three right caudals except U. magna which was
shown as having two by Pierantoni (1909), although he also observed only two right caudals
in U. transfuga which others have shown to possess three. Bullington (1940) discussed the
attachment and movement of the right caudal cirri in Uronychia (Fig. 24).

In addition to these three groups of large cirri, two small right marginal cirri have been
observed in most Uronychia species. Fenchel (1965) distinguished U. bivalvorum from U.
transfuga partly by the absence of these two small cirri but it should be noted that both U.
transfuga and U. setigera have also been described without right marginals.

Fig. 24 Arrangement of the right caudal cirri of Uronychia transfuga, after Bullington, 1940
(called U. heinrothi): (a) showing two large cirri attached in the mid-dorsal region of the posterior
body end with a cirrus on the right; (b) showing two defimbriated cirri attached to either side of
the mid-line and one cirrus attached in a pocket near the right edge and slightly below the other
two cirri.

REVIEW OF EUPLOTIDAE

219

Fig. 25 Stages in cell division of Uronychia transfuga, after Calkins, 1911: (a) resting stage; (b)
condensation of the macronucleus; (c, d) later stages in division; (e) just before cell separation;
(f-h) daughter cells immediately, 15 minutes and 1 hour after separation.

Kahl (1932) noted the presence of a long slender right caudal cirrus in U. binucleata which
he considered to be of diagnostic value, similarly Young (1922) described such a cirrus in U.
setigera although no others have reported its presence. It is evident that cirral numbers and
arrangements in this genus are highly variable and therefore of little diagnostic importance.

(e} Nuclear features. Kahl (1932) relied heavily on the nuclear features of Uronychia in his
key to the species. For example, he stated that U. transfuga had, without exception, two
sausage-shaped macronuclei with a micronucleus and that U. magna and U. heinrothi had
their nuclei split into many fragments. However, U. transfuga had already been seen with its
macronucleus in many fragments. Calkins (1911) described the nuclear reorganisation of U.
transfuga and showed that the macronucleus just after cell division was in two parts but that
it was a fragmented C-shape when at the resting stage (Fig. 25). The macronucleus of U.
transfuga has been described as having a fragmented C-shape, like a string of beads or
partially fused, and in two parts (Fig. 26) (Buddenbrock, 1920; Bullington, 1940). Borror
(1972) has also noted that the macronuclear shape and number were variable and for this
reason considered U. heinrothi to be synonymous with the type species.

Calkins (1902) described U. setigera with a single ovoid macronucleus but Young (1922)
observed two irregular macronuclei in his specimens of the same species. Fenchel (1965)
distinguished U. bivalvorum from the type species partly on the basis of its nucleus which he
described as 'an irregular structure divided into two or more parts of unequal size': this
would lie within the range of variability already noted above for U. transfuga. Kattar(1970)
distinguished between U. transfuga and U. setigera by their possession of 9-15 and 2 nodular
macronuclei respectively, although he also concluded that the six species recognised by Kahl
(1932) including U. setigera could be varieties of U. transfuga. Although the number and
shape of the macronuclei in Uronychia appear to be highly variable this is not the case with

220

C. R. CURDS & I. C. H. WU

€

Fig. 26 Nuclear variation in Uronychia transfuga, after Buddenbrock, 1920 (called V. heinrothi).

the micronucleus. Most species possess a single micronucleus but U. binucleata is charac-
terised by the presence of two micronuclei. Only one other species, U. magna, has been
recorded with two micronuclei.

(/) Dorsal silver-line system. Kattar (1970) noted the presence of four kinetics on the dorsal
surface of U. transfuga and five on U. setigera, while Reiff (1968) illustrated five dorsolateral
kinetics on the former species. The kinetics which have only recently been described appear
to correspond in number and position with the dorsal ridges and striations that are
sometimes described by earlier authors. However, far more data are required before the
diagnostic importance of the silver-line systems of Uronychia can be assessed.

Diagnosis of Uronychia

Marine hypotrichs of variable size, mostly within the range 50-250 urn long, but up to
450 um long. Body oval and smooth in outline, dorsal surface smooth or with ridges.
Peristome large with conspicuous membranes. The AZM is limited to the anterior border
and the paroral region. There are 4-5 transverse and 2 left marginal cirri which emerge from
prominent ventral cavities. The 3 large right caudal cirri are attached to the dorsal surface
and there are sometimes 2 right marginal cirri present. The frontoventral cirri are reduced to
a field of 3 near the origin of the AZM. The macronuclei are variable in number and shape
and there are 1 or 2 micronuclei. Characteristically moves backwards rapidly.

Key to the species of Uronychia

50-250 um long

Smaller than 50 um long or larger than 250 um long

With a single micronucleus

With two micronuclei

Peristomial cirri present

Peristomial cirri absent

40-50 um long

About 450 um long

About 450 urn long, macronucleus moniliform and C-shaped
60-80 um long, macronucleus in 3-5 pieces ....

2
4
3
5

U. setigera

U. transfuga

U. setigera

U. magna

U. binucleata

Species descriptions
Uronychia transfuga (Muller, 1 786) Stein, 1 859

Trichoda transfuga Muller, 1 786
Ploesconia scutum Dujardin, 1841 (in part)
Campylopus paradoxus Claparede & Lachmann, 1 858
Uronychia heinrothi Buddenbrock, 1920
Uronychia uncinata Taylor, 1928
Uronychia bivalvorum Fenchel, 1965

REVIEW OF EUPLOTIDAE

221

-•M- P

Fig. 27 Uronychia transfuga: (a, b) ventral and dorsal surfaces, after Stein, 1859a; (c, d) ventral
and dorsal surfaces, afier Claparede & Lachmann, 1858 (called Campylopus paradoxus); (e)
dorsal surface, after Dujardin, 1841 (called Ploesconia scutum); (f, g) ventral and dorsal surfaces
showing nuclei, after Pierantoni, 1909; (h) ventral surface and nuclei, after Calkins, 1911; (i)
dorsal surfaces and nuclei, after Young, 1922.

222

C. R. CURDS & I. C. H. WU

FMZ

vFM

IMC

Fig. 28 Uronychia transfuga: (a-c) ventral and dorsal surfaces showing nuclei, after Kahl, 1 932 (c
called U. uncinata); (d-f) ventral and dorsal surfaces and nuclei, after Fenchel, 1965 (called V.
bivalvorum); (g, h) ventral surface and dorsal surfaces showing nuclei, after Reiff, 1968.

REVIEW OF EUPLOTIDAE

223

Fig. 29 Uronychia transfuga: (a, b) ventral surface and nuclei, after Kattar, 1970; (c) ventral
surface, after Fenchel, 1965 (called U. bivalvorum)', (d-g) ventral surface, dorsal surface showing
nucleus, ventral view and lateral view of peristomial membranes, after Buddenbrock, 1920
(called U. heinrothi); (h) ventral surface, after Bullington, 1940 (called U. heinrothi); (i) dorsal
surface, after Taylor, 1928 (called U. uncinata).

224

C. R. CURDS & I.C. H. WU

DESCRIPTION (Figs 27, 28 & 29). This is a cosmopolitan species. The oval shaped body is
variable in size (50-260 urn long), its dorsal surface is arched and may be smooth or with 3-4
ridges. At the posterior right there are the 3 characteristically sickle-shaped right caudal cirri.
The large peristome and two posterior cavities occupy most of the ventral surface.
Prominent adoral membranelles are situated along the anterior edge of the body and these
emerge dorsally. At the posterior left of the peristome, there are 4-5 paroral membranelles
lying in a pocket-like invagination. Large undulating membranes border two sides of the
peristome. There are 4-5 large transverse cirri implanted in the larger posterior cavity on the
right, sometimes with 1 or 2 satellite cirri. In the posterior left cavity there are 2 large
marginal cirri sometimes accompanied by a few, usually 2, small cirri or cilia. The
macronucleus varies from being a moniliform (5-13 segments) C-shape at resting stage, to
being 2 irregular masses immediately after cell division. The silver-line system consists of
3-5 dorsolateral kinetics. It has been observed in the mantle cavities of the lamellibranch
molluscs Thyasiraflexuosa and T. sarsi.

10JJ

Fig. 30 Uronychia setigera: (a) after Calkins, 1902; (b-d) after Young, 1922; (e) after Kattar,

1970.

REVIEW OF EUPLOTIDAE

225

NOTES. Stein (1859<2, b) established the genus Uronychia and redescribed U. (Trichoda)
transfuga Muller as the type species. U. transfuga has since been identified by many workers
from various localities (see Hartwig 1973, 1974). As discussed earlier U. heinrothi, U.
uncinata and U. bivalvorum were established on characters that are now known to be
variable and unreliable. These three species are here regarded as synonyms of the type
species until more convincing data become available.

Uronychia setigem Calkins, 1 902

DESCRIPTION (Fig. 30). This is the smallest (40-50 urn long) species yet described. The dorsal
surface is arched and is sculptured longitudinally by 3-4 ridges. There are 2-3 flagella-like
cirri in the large peristome and there are about 4 paroral membranelles. Wide undulating
membranes lie on each side of the peristome. There are 3 curved right caudal cirri attached
dorsally and a long thin satellite cirrus has been observed. In the two ventral cavities there
are 4-5 transverse cirri and 2 large left marginal cirri. The macronucleus is usually in 2 band-
like parts with a micronucleus between them but a single spherical macronucleus has also
been observed in this species. There are 5 dorsolateral kinetics.

NOTES. This species is characterised by the presence of flagella-like cirri extending from the
posterior left margin into the peristome (Calkins, 1902). This author further distinguished it
from the type species by its single ovoid macronucleus; however later authors (Young, 1922;
Kattar, 1970) reported two macronuclei. Kattar (1970) impregnated the cell with protargol
but failed to clearly illustrate the silver-line system.

..ctrr.

SOyum

Fig. 31 Uronychia magna, after Pier^.ntoni, 1 909; (a) ventral surface; (b) dorsal surface.

226

C. R. CURDS & I. C. H. WU

Uronychia magna Pierantoni, 1909

DESCRIPTION (Fig. 3 1 ). This is the largest species yet recorded (450 um long). The body shape
is approximately oval in outline but is ornamented at either end. The anterior dorsal edge is
serrated and there are two short spines on the posterior left dorsal border. The dorsal surface
is longitudinally striated. The peristome is extensive, occupying most of the ventral surface.
The AZM is located anteriorly in a posterior pocket in the peristome. There are two large
undulating membranes, one on each side of the peristome. There are 6 transverse, 2 left
marginal and 3 right caudal cirri. The macronucleus is in many pieces forming a string of
beads which follow the curve of the left side of the body so that it is C-shaped. Anteriorly
there are 2 micronuclei.

NOTE. This species has apparently been described on a single occasion.

Uronychia binucleata Young, 1 922
DESCRIPTION (Fig. 32). Uronychia binucleata is 60-80 urn long. The dorsal surface is arched

10yum

Fig. 32 Uronvchia binucleata: (a-c) ventral surface, dorsal surface and nuclear features, after

Young, !922;(d)afterKahl, 1 932.

REVIEW OF EUPLOTIDAE

227

and decorated with many small pits. The peristome is bordered on either side by a large
undulating membrane and at the anterior left there are 3 delicate sickle-shaped
membranelles. About 4 paroral membranelles lie in the 'buccal' pocket. There is a long
slender cirrus accompanying the 3 curved right caudal cirri, 4 transverse, 2 left marginal and
2 right marginal cirri. The macronucleus is in 3-5 fragments and 2 micronuclei.

NOTES. Young (1922) established this species which he showed to be almost identical to U.
setigera in his comparative study. He distinguished his species by the absence of peristomial
cirri, the presence of 4 or less transverse cirri, and the presence of a slender right caudal cirrus
in addition to the two micronuclei. Although Young (1922) described a satellite cirrus in U.
setigera which he considered to be significant, curiously he failed to mention it in U.
binucleata even though he illustrated it. Here the presence of two micronuclei is used to
characterise the species: should future studies show that the number of micronuclei to be
variable, then it would become synonymous with U. transfuga.

Genus CERTESIA Fabre-Domergue, 1885

Introduction

Fabre-Domergue (1885) described an organism that was very similar to Euplotes except that
it had a row of left marginal cirri, no caudal cirri and the macronucleus was in four parts. In
his view this was sufficient to create the new genus Certesia although later both Biitschli
(1 889) and Sauerbrey (1928) considered it to be a subgenus of Euplotes. Since the description
of the type species, Certesia quadrinucleata Fabre-Domergue, 1885, only one other species,
Certesia ovata Vacelet, 1960, has been described. Vacelet (1960) distinguished it from the
type species on account of its smaller size, its more oval shape and its two curved left
transverse cirri. Here, these differences are not considered to be sufficient to treat C. ovata as
a separate species.

Diagnosis of Certesia

Oval marine hypotrichs with an anterior nose-like projection on the right anterior body
edge. There is a conspicuous AZM which extends a third to halfway down the left side of the
body. There are 1 1-13 frontoventral, 5 large transverse, and a variable number (6-1 1) of left
marginal cirri. There are no caudal cirri. Macronucleus in several parts. Single species genus.

20/jm

Fig. 33 Certesia quadrinucleata: (a) after Fabre-Domergue, 1885; (b) after Sauerbrey, 1928; (c)
after Kahl, 1932;(d, e) after Vacelet, 1960 (called C. ovata).

228 C. R. CURDS & I. C. H. WU

Species description

Certesia quadrinucleata Fabre-Domergue, 1885
Certesia ovata Vacelet, 1 960

DESCRIPTION (Fig. 33). Certesia quadrinucleata is a medium sized (75-80 fim long), oval,
rigid and colourless marine hypotrich. The dorsal surface is arched and smooth: the ventral
surface flat. The right body border is convex and the left may be slightly concave. There is a
distinct nose-like projection on the right of the extreme anterior body edge. The peristome is
a third to a half of the body length. The AZM consists of about 5 large membranelles along
the anterior border and 1 5-20 smaller ones along the left edge of the peristome. There are
1 1-13 frontoventral cirri, 5 large transverse cirri, a row of 6-1 1 left marginal cirri but no
caudal cirri. Four ovoid macronuclei are located in pairs, one pair on the right anterior and
one pair on the left below the AZM.

Genus GASTROCIRRHUS Lepsi, 1928

Introduction

Lepsi (1928) created the genus Gastrocirrhus and stated that the type species Gastrocirrhus
intermedium Lepsi, 1928 possessed characters that were intermediate between the oligotrichs
and the hypotrichs. The organism had ventral cirri arranged in groups like those of
hypotrichs, but its large anterior funnel-shaped peristome and spiral AZM were more like
those of oligotrich genera such as Stentor. Kahl (1932) thought that the organism was
probably a piece of a fragmented Oxytricha, but soon after Bullington (1940) established
another species Gastrocirrhus stentoreus Bullington, 1940. This has been followed by several
other species descriptions.

The six cirri along the right side of G. intermedius are here interpreted to be frontoventrals
and the remaining ten cirri are called caudals. Bullington (1940) recorded the presence of
four marginals, four ventral and two oral/anterior cirri on G. stentoreus. These are
considered to be frontoventral cirri so that this species may be diagnosed by the presence of
only five caudal cirri. In Gastrocirrhus adhaerens Faure-Fremiet, 1954, there are 16 cirri
arranged in two rows on the right of the peristome, and 12 in a semi-circle at the posterior.
Here, these are interpreted to be frontoventral and caudal cirri respectively. Gastrocirrhus
trichocystus Ito, 1958 has 18 frontoventral and 13 caudal cirri arranged similarly to those in
G. adhaerens but the species is characterised by the presence of zones of trichocysts
(mucocysts?) on the dorsal and ventral surfaces.

Faure-Fremiet (1961) created the family Gastrocirrhidae and included the single species
genus Cirrhogaster Ozaki & Yagui, 1942 in the family. The type species, Cirrhogaster
monilifer Ozaki & Yagui, 1942 is similar to G. adhaerens, but the former species has 10
rather than 16 frontoventral cirri. Dragesco (1965) suggested that these two species were
synonymous but here, although C. monilifer is considered to be a species of Gastrocirrhus it
is not considered to be a synonym of G. adhaerens.

Diagnosis of Gastrocirrhus

Marine hypotrichs that may be dorso vent rally flattened or cup-shaped. There is a large
anterior funnel-shaped peristome which opens both anteriorly and ventrally. A well
developed AZM borders the C-shaped anterior body edge and winds anti-clockwise down the
left of the peristome. There are 5-18 frontoventral cirri, usually arranged in two oblique
rows on the right of the peristome: 5-13 caudal cirri along the posterior pole of the body
which in some species curve forwards ventrally on the left to give the appearance of
transverse cirri. Macronucleus may be oval or moniliform in 11-15 pieces.

REVIEW OF EUPLOTIDAE

229

Key to the species of Gastrocirrhus

\ With 10 fronto ventral cirri 4

With 6, or more than 10 frontoventral cirri 2

2 With 6 frontoventral cirri G. intermedius

With more than 10 frontoventral cirri 3

3 With 1 6 frontoventral cirri and 1 2 thigmotactic caudal cirri, without 'trichocyst' zones

G. adhaerens
With 1 8 frontoventral cirri, 1 3 caudal cirri and with dorsal and ventral zones of 'trichocysts'

G. trichocystus

4 With 5 caudal cirri G. stentoreus

With 12-13 caudal cirri G.monilifer

10/jm

Fig. 34 Gastrocirrhus intermedius, after Lepsj, 1 928.
Species descriptions

Gastrocirrhus intermedius Lepsi, 1928

DESCRIPTION (Fig. 34). This species is a dorso ventral ly flattened cup-shape, approximately
70 jim long. The well developed AZM borders the anterior funnel-shaped peristome. There
are 16 cirri in three distinct groups. Near the right body margin there are 6 frontoventral
cirri. The caudals are situated along the posterior pole, comprised of a group of 3 sickle-
shaped cirri, rather like the right caudal cirri in Diophrys, and 7 others to their left which are
smaller and straighten The macron ucleus is oval.

NOTES. There is only a single description of this, the type species of the genus. The
observations of Lepsi (1928) appear to have been made exclusively on living specimens. The
arrangement of the cirri and nuclear features do not appear to be as typical as those of the
species described later.

Gastrocirrhus stentoreus Bullington, 1940

DESCRIPTION (Fig. 35). Gastrocirrhus stentoreus is a medium sized (100 urn long, 70-80 um
wide) perfectly cup-shaped species. The large funnel-shaped peristome has a ventral,
elongate opening about two-thirds of the body length and is bordered by a prominent AZM.
There are 1 1 frontoventral cirri on the right of the peristome in groups of two, four and five
cirri. At the posterior right margin, there are 5 sickle-shaped caudal cirri.

230

C. R. CURDS & I. C. H. WU
^

SOiim

Fig. 35 Gastrocirrhus stentoreus, after Bullington, 1 940.

Fig. 36 Gastrocirrhus adhaerens: (a) ventral surface; (b) attached to substratum showing nuclei.

Both after Faure-Fremiet, 1954.

Gastrocirrhus adhaerens Faure-Fremiet, 1954

DESCRIPTION (Fig. 36). This is a medium sized (100 urn long), typically cup-shaped species.
The peristome diameter is slightly less than the body length. The AZM, which winds around
the anterior of the cell and down the left side of the peristome, consists of about 150
membranelles. The species is characterised by its 12 very long thigmotactic caudal cirri
along the posterior border of the cell which can be retracted when not attached to a
substratum. There are 16 frontoventral cirri arranged in two rows of 8 cirri on the right of the

REVIEW OF EUPLOTIDAE

231

peristome. The moniliform macronucleus is composed of about 12 pieces: 3-5 micronuclei
have been observed.

Gastrocirrhus monilifer n. comb.
Cirrhogaster monilifer Ozaki & Yagui, 1942

DESCRIPTION (Fig. 37). Gastrocirrhus monilifer is 95-105 urn long, 75-90 urn wide and cup-
shaped. The ventral opening into the large funnel-shaped peristome is about a half the body
length. The 10 frontoventral cirri, arranged in two rows, are restricted to the small area on
the right of the peristome. There are 12 long caudal cirri. The moniliform macronucleus
consists of 1 1-1 5 pieces and there are 8 micronuclei scattered along its length.

NOTES. Dragesco (1965) suggested that this species should be a synonym of G. adhaerens.
Here it is considered to be a separate species until further information concerning the
variability in numbers of frontoventral cirri become available.

Fig. 37 Gastrocirrhus monilifer, after Ozaki & Yagui, 1 942 (called Cirrhogaster monilifer).

Gastrocirrhus trichcystus Ito, 1958

DESCRIPTION (Fig. 38). Gastrocirrhus trichocystus is 90-103 um long, 82-90 urn wide and
cup-shaped. The ventral surface becomes flattened when starved. The large peristome is
bordered by numerous long adoral membranelles. There are 18 frontoventral and 13 caudal
cirri separated by longitudinal ridges on the ventral surface. The sickle-shaped macronucleus
is moniliform with 10-12 pieces. There are usually 8 micronuclei. The species is
characterised by bands of 'trichocysts' (mucocysts?) along the anterior and right margin of
the dorsal surface, also they are found along the left margin and at the anterior right on the
ventral surface.

232

C. R. CURDS & I. C. H. WU

O 0 0 0 °

U> o o o °
\0 0 0 o 0
\C 0

O O >

: •'.:

o °o

°0

0 00

o°0o

o n0

° ° 0

oo0

O Q/

Fig. 38 Gastrocirrhus trichocystus, after Ito, 1958: (a) ventral surface; (b, c) ventral and dorsal

surfaces showing trichocyst distribution.

Genus EUPLOTASPIS Chatton & Seguela, 1936

Introduction

Chatton & Seguela (1936) described a Euplotes-like hypotrich found in the branchial cavity
of the sea squirt, dona intestinalis. They noted that the organisms were never observed on
or around their host and they did not survive without their host for more than 36 hours in a
medium which had been used successfully for the culture of many marine Euplotes.

This species was found to have many characters similar to those of Euplotes but Chatton &
Seguela (1936) noted that its body shape and very thick short cirri were more like those of
Aspidisca. Furthermore, the AZM was entirely ventral so that it did not border the anterior
dorsal surface as in Euplotes, and four of the frontoventral cirri were split into two parts
which is a distinctive feature. Corliss (1961) placed this genus along with Paraeuplotes in the
family Paraeuplotidae but later (Corliss, 1977) he transferred it to the family Aspidiscidae.

REVIEW OF EUPLOTIDAE

233

Diagnosis of Euplotaspis

Marine oval hypotrichs living in sea squirts. There is a prominent AZM restricted to the
ventral surface. There are 9 frontoventral, 5 transverse and 3—4 caudal cirri. The four
frontoventral cirri towards the right body border are split longitudinally into two parts.
Macronucleus C-shaped. The dorsal argyrome is like that of Euplotes vannus (see Curds,
1975).

Species description

Euplotaspis cionaecola Chatton & Seguela, 1936

DESCRIPTION (Fig. 39). Euplotaspis cionaecola is a 60-70 um long marine hypotrich found in

rv-'x ;<N

£> \ ::..x A u

,/ /--T ,-(' 1A _^

^ ri 4---"\- J !'

,.-\ f-

v — 4

<v ..*
.-.-4 I-
_>- ) — v-

V""' i

Fig. 39 Euplotaspis cionaecola, after Chatton & Seguela, 1936: (a) ventral surface of living cell;
(b, c) ventral and dorsal surfaces of silver-impregnated specimens.

234 C. R. CURDS & I. C. H. WU

the branchial cavity ofCiona intestinalis. The body outline is perfectly oval, convex dorsally
and flattened or slightly concave ventrally. The AZM of about 50 membranelles, is a
prominent band parallel to, and at a short distance from, the left body margin. There are 10
short, wide frontoventral cirri: the four on the right being split longitudinally. The 5
transverse cirri are separated by marked ridges on the ventral surface. The 3-4 caudal cirri
are small and indistinct in vivo but can be seen in silver impregnated specimens. The dorsal
silver-line system consists of 7-8 dorsal kinetics, each carrying about 1 5 cilia, with simple
cross-links between the kinetics. The macronucleus is C-shaped and a single micronucleus
has been observed at its posterior left.

Genus EUPLOTIDIUM Noland, 1937

Introduction

Noland (1937) described a hypotrich found in sponges from the Gulf of Mexico and stated
that 'the organism differs from Euplotes, its nearest relative, in the absence of caudal cirri,
and in the more cylindrical shape of the body'. Consequently, he erected the genus
Euplotidium Noland, 1937 and called the organism Euplotidium agitatum Noland, 1937
because of its erratic movements. Ito (1958) also described a cylindrical Euplotes-\ike
organism, but in this species there was one left caudal cirrus and more frontoventral and
transverse cirri than in E. agitatum, this he called Euplotidium itoi Ito, 1958. A further
species with different numbers of frontoventral and transverse cirri, Euplotidium arenarium
Magagnini & Nobili, 1964, was later described and Borror (1972) transferred Euplotes
psammophilus Vacelet, 1961 to the genus. More recently Hartwig (1980) added another
species to the genus.

Diagnosis of Euplotidium

Small to large (65-200 um long) marine hypotrichs. Outline shape slightly elongated oval.
Rounded in cross-section, never dorso ventrally flattened. The peristome is a wide funnel-
shape with a prominent AZM that borders both the anterior semi-circular body edge and the
left margin of the peristome. There are 7-12 frontoventral, 5-6 transverse and, when present,
a reduced number (1-2) of caudal cirri.

Key to the species of Euplotidium

1 With less than 10 frontoventral cirri 2

With 10 or more frontoventral cirri 4

2 With 9 frontoventral cirri but without caudal cirri E. agitatum

With 7 frontoventral and 1 or 2 caudal cirri 3

3 With 1 caudal cirrus, macronucleus in many parts E. helgae

With 2 caudal cirri, macronucleus elongate E. psammophilus

4 With 10 frontoventral and more than 1 caudal cirri E. arenarium

With 12 frontoventrals and 1 caudal cirrus E. itoi

Species descriptions

Euplotidium agitatum Noland, 1937

DESCRIPTION (Fig. 40). This, the type species, is 65-95 um long and its cylindrical body
shape is most apparent when viewed from the anterior. There is a funnel-shaped peristome
which is lined around its anterior rim and left side by a prominent AZM. There are
approximately 40 membranelles on the anterior part and about the same number in the

REVIEW OF EUPLOTIDAE

235

Fig. 40 Euplotidium agitatum, after Noland, 1937: (a) ventral surface; (b) dorsal surface; (c) view

from anterior showing cylindrical body.

ventral part of the AZM. There are 9 frontoventral cirri, aligned in 2 rows, near the right
body edge and 5 conspicuous transverse cirri but caudal cirri are not present.

NOTE. Originally isolated from water squeezed from sponges in the Gulf of Mexico.

Euplotidium itoi Ito, 1958

DESCRIPTION (Fig. 41). This is a medium sized (89-95 um long), cylindrical hypotrich with a
slightly flattened ventral surface. The AZM borders the anterior and left edges of the
peristome forming a sigmoid shape. Nine of the 12 frontoventral cirri are in 2 oblique rows
situated near the anterior right of the peristome while the other 3 are scattered along the right
body edge. There are 6 large transverse cirri and a single small left caudal cirrus. The
macronucleus is in 2 ribbon-like parts with 4 micronuclei.

NOTES. The position of the reorganisation band in Ito's (1958) diagram indicates that it could
have been at some stage of division. Originally found in seaweed in the Inland Sea of Japan.

Euplotidium arenarium Magagnini & Nobili, 1964
DESCRIPTION (Fig. 42). This is a medium sized (71-120 um long) oval species with a wide

236

C. R. CURDS & I. C. H. WU

Fig. 41 Euplotidium itoi, after Ito, 1958.

triangular peristome. The AZM consists of about 75 membranelles and it extends around the
anterior semi-circular rim of the peristome down to the left side. There are 10 fron to ventral s,
5 transversals and a single left caudal cirrus. The transverse cirri are not conspicuous as in
the other species of the genus and could be overlooked. The macronucleus is moniliform, in
5-10 pieces, and is curved towards the right. The silver-line system consists of 2 marginal
kinetics confluent posteriorly and there are dorsal and ventral mesh-like argyromes.

NOTE. Originally isolated from sand in the Gulf of Naples.

Euplotidium psammophilus (Vacelet, 1961)Borror, 1972
Euplotes psammophilus Vacelet, 1 96 1

DESCRIPTION (Fig. 43). This is a large (125 urn long) species in which the wide peristome
extends about two-thirds down the length of the body. There are 7 frontoventral cirri
arranged in 2 groups on the right of the peristome. Three are closely packed together at the
anterior and 4 are in a row behind them. The 5 transverse cirri are long and there are 2
caudal cirri. Vacelet (1961) also described the presence of a row of short cilia along the
posterior right body edge. The elongated curved macronucleus is rod-like with an adjacent
micronucleus.

NOTES. This was originally described as a species of Euplotes', Borror (1972) transferred it to
Euplotidium on account of the shape of the body and peristome and because of the reduced
number of caudal cirri.

Euplotidium helgae Hart wig, 1980
DESCRIPTION (Fig. 44). This is the largest (up to 200 urn long) of the species. The peristome

Fig. 42 Euplotidium arenarium, after Magagnini & Nobili, 1964; (a) ventral surface of living cell;
(b, c) ventral and dorsal surfaces of silver-impregnated specimens; (d) stages in nuclear
reorganisation.

238

C. R. CURDS & I. C. H. WU

20iim

Fig. 43 Euplotidium psammophilus, after Vacelet, 1961 (called Euplotes psammophilus): (a)

ventral surface; (b) nuclear apparatus.

50yu

Fig. 44 Euplotidium helgae, after Hartwig, 1 980.

extends about two-thirds down the body length. The original author (Hartwig, 1980) was not
too sure about the cirral pattern and the interpretation used here is based on the assumption
that there are 5 transverse and 7 frontoventral cirri rather than 4 transverse and 8
frontoventral cirri. There is a single caudal cirrus on the left and the fronto ventral s are
arranged in a single group on the right of the peristome. The macronucleus consists of 1 1
oval parts arranged in the shape of the letter C. There are several micronuclei.

NOTE. Originally found in sand in Bermuda.

REVIEW OF EUPLOTIDAE

Genus PARAEUPLOTES Wichlerman, 1942

239

Introduction

Wichterman (1942) described a hypotrichous ciliate which he found in abundance on the
coral Eunicea crassa in the Tortugas. The species resembled Euplotes in that it had a well
developed AZM and a C-shaped macronucleus, but its rather peculiar ciliature bore no
resemblance to that of Euplotes. He called the genus Paraeuplotes Wichterman, 1942 and
placed it in a new family, the Paraeuplotidae Wichterman, 1942. Here, following Horror
(1972) and Corliss (1977) the genus is provisionally included in the Euplotidae.

Diagnosis of Paraeuplotes

Discoid marine hypotrich with a well-developed AZM which originates on the dorsal surface
and curves down three-quarters of the body length on the ventral surface. Undulating
membrane absent. There are no marginal cirri but there is a small group of short caudal cirri.
There is an extensive arc of transverse cirri parallel with the right body edge. Anteriorly,
there is an arc of cilia parallel with the apical body edge and an isolated pair of cirri in the
midventral position. The macronucleus is C-shaped. Contains numerous zooxanthellae.

20>um

Fig. 45 Paraeuplotes tortugensis, after Wichterman, 1942: (a) ventral surface; (b) dorsal surface;

240 C. R. CURDS & I. C. H. WU

Species description

Paraeuplotes tortugensis Wichterman, 1942

DESCRIPTION (Fig. 45). Small to medium discoid species measuring on average 80 um in
diameter. The well-developed AZM forms a collar-like structure on the anterior dorsal
surface which extends ventrally down about three-quarters of the body length. There is no
undulating membrane present. Anteriorly there is an arc of cilia parallel with the body edge
and a pair of isolated cirri lying in a midventral position. There is an extensive arc of
transverse cirri parallel with the right body edge and a group of 5-6 short caudal cirri slightly
to the right of the posterior body pole. The macronucleus is C-shaped. The cell is packed
with numerous yellow-brown zooxanthellae.

NOTE. Originally isolated from the coral Eunice crassa in the Tortugas.

Genus SWEDMARKIA Dragesco, 1954

Introduction

Dragesco (1954, 1960, 1965) studied and described this genus over a period of several years.
He (Dragesco, 1960, 1965) likened the genus to Euplotidium and Gastrocirrhus and
considered it to be a possible evolutionary link between the Holostichidae Faure-Fremiet,
1961 and the Euplotidae. Both Faure-Fremiet (1961) and Corliss (1977) placed Swedmarkia
in the family Gastrocirrhidae but it is here provisionally included in the Euplotidae.

Diagnosis of Swedmarkia

Medium sized (100-1 10 jim long) marine hypotrichs with conspicuous AZM arranged
around a wide triangular peristome. There are two particularly long membranelles at the left
of the apex of the peristome. A wide undulating membrane lies on the right of the peristome.
There are many (54-58) cirri present with the following distribution. Numerous
frontoventrals include a row along the right peristome edge, an apical group and an irregular
midventral row. There are 5 large transverse and rows of right and left marginal cirri that are
confluent posteriorly. The macronucleus is divided into numerous (about 100) portions and
there are 5-9 micronuclei.

Species description

Swedmarkia arenicola Dragesco, 1954

DESCRIPTION (Fig. 46). This is a medium sized (100-1 10 urn long) marine hypotrich, similar
in shape to Euplotes. The body is oval to triangular in shape and there is a large triangular
peristome which extends down three-quarters of the body length where it occupies about half
of the ventral surface. The AZM consists of 54-68 membranelles of which two, at the
extreme left apex of the peristome, are particularly long. There is a wide undulating
membrane on the right peristome border. The total of 54-58 cirri are arranged as follows, a
row of fron to ventral (peristomial) cirri is spaced evenly along the right peristomial edge. A
group of 6 frontoventral cirri are situated around the extreme apex of the cell and there is an
irregular row of 5 frontoventrals lying in the midventral position. Additionally, a short row
of left marginal cirri is present with an irregularly spaced row of right marginals, of which the
anterior half arise from the dorsal surface. The marginals are continuous along the posterior
border. The macronucleus is divided into numerous (about 100) spherical pieces and there
are 5-9 micronuclei. The three dorsal kinetics bearing double cilia are illustrated in Fig. 46b.

REVIEW OF EUPLOTIDAE

241

Fig. 46 Swedmarkia arenicola, after Dragesco, 1965: (a) ventral surface; (b) dorsal surface; (c, d)
ventral surface showing variations in form, number and arrangement of certain cirri.

242

C. R. CURDS & I. C. H. WU

Genus GRUBERELLA (Gruber, 1884) Corliss, 1960

Stylocoma Gruber, 1 884
Introduction

Gruber (1884) described the marine hypotrich Stylocoma oviformis Gruber, 1884 which
Kahl (1932) redescribed and placed in the family Euplotidae. Soon after, another species,
Stylocoma adriatica Kiesselbach, 1936, which lacked transverse cirri, was described. Corliss
(1960) pointed out that the generic name was preoccupied by Stylocoma Lioy, 1864 a
dipteran insect, and proposed that it should be replaced by Gruberella Corliss, 1960. Borror
(1972) considered the genus to be of questionable status but Corliss (1977) included it as an
incertae sedis in the Sporadotrichina. Here, the genus is provisionally included in the
Euplotidae on account of its funnel-like peristome, which is reminiscent of Gastrocirrhus,
and the arrangement of cirri which, although reduced, are more like those in the Euplotidae
than in any other family of hypotrichs.

Diagnosis of Gruberella

Ovoid, marine hypotrichs, rounded in cross-section. There is a centrally placed funnel-
shaped peristome bordered by a conspicuous AZM anteriorly and down the left side. Cirri
reduced. Caudal cirri present, transverse cirri may or may not be present. Frontoventral and
marginal cirri absent. Macronucleus in two parts.

Key to the species of Gruberella

1 With 6 caudal and 7 transverse cirri .
With 6 caudal but without transverse cirri

G. oviformis
G. adriatica

Species descriptions

Gruberella oviformis (Gruber, 1 884) Corliss, 1960
Stylocoma oviformis Gruber, 1 884

DESCRIPTION (Fig. 47). Ovoid marine hypotrich with wide, centrally placed, funnel-shaped
peristome which has a slightly raised edge forming an anterior collar-like region. The

Fig. 47 Gruberella oviformis: (a) after Gruber, 1 884; (b) after Kisselbach, 1936.

REVIEW OF EUPLOTIDAE 243

prominent AZM consisting of many large membranelles originates on the ventral surface on
the right of the peristome and continues around the apex down the left side. There are only 2
groups of cirri, 7 transverse and 6 long caudal cirri. No frontoventral or marginal cirri are
present. Shape of macronucleus unrecorded.

Gmberella adriatica (Kisselbach, 1936) Corliss, 1960
Stylocoma adriatica Kiesselbach, 1936

DESCRIPTION (Fig. 48). Medium sized (80 um long) triangular shaped marine hypotrich with
funnel-shaped, centrally positioned peristome. Prominent AZM borders the anterior and left
peristomial edges. Cirri reduced to a single group of 6 long caudals. There are no transverse,
frontoventral or marginal cirri present. Macronucleus divided into 2 ovoid pieces with a
micronucleus between the pair.

Fig. 48 Gruberella adriatica, after Kisselbach, 1 936.
Genus CYATHAROIDESTuffrau, 1975

Introduction

Tuffrau (1975) described a species from Antarctica which closely resembled Euplotes in
certain respects but not in others. It is characterised by the presence of a row of 12 large right
marginal cirri in addition to the usual frontoventral and transverse cirri. Furthermore, there
is an extensive paroral membrane composed of a single kinety of long cilia which is unlike
the undulating membrane of Euplotes and there is also endoral ciliature which is not found
in Euplotes.

Diagnosis of Cyatharoides

Irregularly oval marine hypotrich with a very large peristomial funnel occupying much of
the ventral surface onto which it opens. The peristome is surrounded by a collar-like
swelling of the anterior left body edge, with a characteristic 'niche' or invagination of the
right anterior peristome region. The AZM is composed of many membranelles lining the left
peristomial border. On the right, at the bottom of the peristomial funnel there is a paroral
membrane composed of a single kinety of long cilia and an arc of endoral cilia. There are 10
frontoventral, 5 transverse and a row of 1 2 right marginal cirri along the right body edge.
Dorsally there are 12-26 kinetics of cilia and the macronucleus is C-shaped.

244

C. R. CURDS & I. C. H. WU

Species description

Cyatharoides balechi Tuffrau, 1 975

DESCRIPTION (Fig. 49). Irregularly oval, large (140-200 urn long) marine, planktonic
hypotrich with a very large peristomial funnel opening over much of the ventral cell surface.
Anteriorly the peristome is surrounded by a collar-like swollen ridge of the anterior left body
edge, with a characteristic invagination of the peristome on the right anterior edge. The
AZM is prominent and composed of many large membranelles. There are paroral and
endoral membranes on the posterior right peristomial edge. With 10 frontoventral, 5
transverse and 12 right marginal cirri. Dorsal surface with 12-26 kinetics of many cilia.
Macronucleus large, open C-shaped.

NOTE. Originally isolated from plankton sample taken from Antarctic Ocean near base of
Argentina by Prof. Balech.

Fig. 49 Cyatharoides balechi, ventral surface, after Tuffrau, 1975.

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Magagnini, G. & Nobili, R. 1964. Su Euplotes woodruffi Gaw e su Euplotidium arenarium n.sp.

(Ciliatea, Hypotrichida). Monitore zool. ital. 12 : 1 78-202.

Mansfeld, K. 1923. 16 neue oder wenig bekannte marine Infusorien. Arch. Protistenk. 46 : 97-140.
Miiller, O. F. 1 786. Animalcula Infusoria Fluviatilia et Marine. 367 pp. Havniae et Lipsiae.
Noland, L. E. 1937. Observations on marine ciliates of the gulf coast of Florida. Trans. Am. microsc.

Soc.56: 160-171.
Ozaki, Y. & Yagui, R. 1942. A new marine ciliate Cirrhogaster monilifer n.g. n.sp. Annotns zool. jap.

21:79-81.

Pierantoni, N. 1909. Su alcuni Euplotidae del Golfo di Napoli. Boll. Soc. Nat. Napoli 1909 : 53-64.
Quennerstedt, A. 1867. Bidragtill a Sveriges Infusorie-fauna. Ada Univ. lund. 4 : 1-47.
Raikov, I. B. & Kovaleva, V. G. 1968. Complements to the fauna of psammobiotic ciliates of the Japan

Sea (Posjet Gulf). Ada Protozool. 6 (27) : 309-333.
Rees, J. van 1881. Zur Kenntnis der Bewimperung der Hypotrichen Ifusorien, nach Beobachtungen an

Styloplotes grandis n.sp. und Euplotes longipes Claparede & Lachmann. Ellerman & Harms,

Amsterdam.

1883-1884. Protozoaires de 1'escautde Test. Tijdschr. ned. dierk. Vereen. Suppl. 1 : 592-673.

Reiff, I. 1968. Die genetische Determination mutlipler Paarungstypen bei dem Ciliaten Uronychia

transfuga (Hypotricha, Euplotidae). Arch. Protistenk. 110 : 372-397.

Ruinen, J. 1938. Notizen uber Ciliaten aus konzentrierten Salzgewassern. Zool. Meded. 20 : 243-256.
Sauerbrey, E. 1928. Beobachtungen uber einige neue oder wenig bekannte marine Ciliaten. Arch.

Protistenk. 62 : 355-407.
Stein, F. 18590. Der Organismus der Infusionsthiere nach eigenen Forsuchungen in Systematischer

Reihenfolge Bearbeitet I. 206 pp. Leipzig.

185%. Charakteristik neuer Infusoriengattungen. Lotos 9 : 2-5. 9 : 57-60.

Summers, F. M. 1935. The division and reorganization of the macronuclei of Aspidisca lynceus

Miiller, Diophrys appendiculata Stein, and Stylonychia pustulata Ehrbg. Arch. Protistenk.

85: 173-208.
Taylor, C. V. 1928. Protoplasmic reorganization of Uronychia uncinata sp.nov. during binary fission

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Tuffrau, M. 1975 (1974). Un nouvel Euplotidae: Cyatharoides balechi, n.g., n.sp., cilie Hypotriche de

1'Anarctique. Prostistologica 10 (3) : 31 1-317.

REVIEW OF EUPLOTIDAE

247

Vacelet, E. 1960. Note preliminaire sur la faune infusorienne des 'Sables a Amphioxus' de la biae de

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36(1): 1-34.
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Zool. 36 : 353-395.

Manuscript received for publication 4 August 1982

Index to Species

(Names given in roman refer to synonyms)

Campylopus paradoxus 220
Certesia ovata 228

quadrinucleata 228
Cirrhogaster monilifer 23 1
Cyatharoides balechi 244

Discocephalus ehrenbergi 195

grandis 195

minimus 197

rotator ius 194

rotatorius 195
Diophrys appendiculata 203

appendiculatus 203

grandis 206

hystrix 207

irmgard2Ql

kahli 209

kasymovi 206

magnus 206

marina 203

multinucleata2\5

oligothrix 2 1 0

peloetes 2 1 0

quadricaudatus 2 1 1

salina 209

scutoides 2 1 2

scutum 203

tetramacronucleata 2 1 4

Euplotaspis cionaecola 233
Euplotes psammophilus 236
Euplotidium agitatum 234

arenarium 235

Helgae236

/to/ 23 5

psammophilus 236

Gastrocirrhus adhaerens 230

intermedius 229

monilifer 231

stentoreus 229

trichocystus23\
Gruberella adriatica 243

oviformis 242

Paraeuplotes tortugensis 240
Planiplotes wagneri 203
Ploesconia scutum 203, 222
Polycoccon octangulus 194
Schizopus norwegicus 203
Stylocoma adratica 243

oviformis 242

Stylonychia appendiculata 203
Styloplotes appendiculatus 203

appendiculatus var pontica 203

fresenii 203

grandis 206

norwegicus 206

quennerstedti 206

Swedmarkia arenicola 240
Trichoda transfuga 220

Uronvchia binucleata 226
bivalvorum 220
heinrothi 220
magna 226
setigera 225
transfuga 220
uncinata220

British Museum (Natural History)

An Atlas of Freshwater Testate Amoebae

C. G. Ogden & R. H. Hedley

1980, Hardcovers, 222pp, £17.50 (£18.00 by post). Co-published by British Museum
(Natural History) and Oxford University Press.

British Museum (Natural History)
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Titles to be published in Volume 44

Observations on the systematics of the genus Difflugia in
Britain (Rhizopoda, Protozoa).

By Colin C. Ogden

Miscellanea

A review of the Euplotidae (Hypotrichida, Ciliophora).

By Colin Curds & Irene C. H. Wu

Osteology, genitalia and relationships of the Acanthodactylus
(Reptilia: Lacertidae). By E. N. Arnold

The Opthalmotilapia assemblage of cichlid fishes reconsidered.

By Peter Humphrey Greenwood

Morphological studies on some Difflugiidae from Yugoslavia
(Rhizopoda, Protozoa).

By Colin G. Ogden & Andjelija Zivkovic

Printed by Henry Ling Ltd, Dorchester

Bulletin of the

British Museum (Natural History)

The Ophthalmotilapia assemblage of
tichlid fishes reconsidered

Peter Humphry Greenwood

Zoology series Vol 44 No 4 28 April 1983

Publications Sales,

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Cromwell Road,

London SW7 5BD,
England.

World List abbreviation: Bull. Br. Mus. not. Hist. (Zool.)

<C) Trustees of the British Museum (Natural History), 1983

The Zoology Series is edited in the Museum's Department of Zoology
Keeper of Zoology : Dr J. G. Sheals
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ISSN 0007-1498 Zoology series

Vol 44 No 4 pp 249-290
British Museum (Natural History)
Cromwell Road
London SW7 5BD Issued 28 April 1983

The Ophthalmotilapia assemblage of cichlid fishes
reconsidered

Peter Humphry Greenwood^

Department of Zoology, British Museum (Natural History), Cromwell Roa
SW7 5BD

Contents

Synopsis 249

Introduction 249

Material examined 250

A review of group characters for the Ophthalmotilapia assemblage . . . 254

The Ophthalmotilapia assemblage reconsidered 262

Relationships within the Ophthalmotilapia assemblage .... 263
The nature of the apophysis for the upper pharyngeal bones in the

Ophthalmotilapia assemblage 274

A review of other schemes of relationship suggested for members of the

Ophthalmotilapia assemblage 275

Summary of the taxonomic conclusions and a discussion of the sister-group

problem in these and other lake cichlids 278

The status of Cyathopharynx Regan, 1 920 and Cardiopharynx Poll, 1 942 . 282

Cyathopharynx Regan, 1920 284

Description 284

Acknowledgements 289

References 290

Synopsis

The Ophthalmotilapia assemblage of cichlid fishes from Lake Tanganyika, first defined by Liem
(1981), originally comprised the genera Asprotilapia, Ectodus, Lestradea, Cunningtonia and
Ophthalmotilapia (with which was synonymized Ophthalmochromis). The characters on which the
assemblage was based are reviewed and revised in the light of information derived from large-scale
outgroup comparisons.

As a result of this review, five additional genera can be included in the assemblage (viz.
Aulonocranus, Grammatotria, Callochromis, Xenotilapia and Cyathopharynx (with which Cardio-
pharynx is synonymized). Two lineages within the Ophthalmotilapia assemblage are defined.

Previous schemes of supposed relationships for these taxa are discussed, as is the problem of
identifying the sister-group for the assemblage. No sister-group can be identified amongst the endemic
taxa of Lake Tanganyika, but the possibility of an endemic taxon from Lake Malawi being the sister-
group is explored.

Problems arising from possible homoplasy and thus the misidentification of sister-groups are
illustrated by examples involving cichlid species from Lakes Tanganyika and Malawi, and from these
lakes and Lake Fwa (Zaire drainage basin).

Introduction

During the last thirty years there has been a marked increase in our knowledge of taxonomic
and ecological diversity amongst African cichlid fishes. Unfortunately there has been less
progress made in our understanding of phyletic relationships between the various elements
of those faunas, or even amongst members of the so-called species flocks of the major African
lakes (see Greenwood, 1980).

Bull. Br. Mm. nat. Hist. (Zool.) 44 (4): 249-290 Issued 28 April 1 983

250 P- H. GREENWOOD

Two recent papers are welcome and important contributions to the field of phyletic
studies since both are concerned with interrelationships in a single species flock, that of Lake
Tanganyika (Liem & Stewart, 1976;Liem, 1981).

Liem's (1981) paper is directed at establishing the monophyletic origin of five endemic
genera from that lake, viz. Asprotilapia, Ectodus, Lestradea, Cunningtonia and Ophthalmo-
tilapia. Although Liem was able to argue a case for recognizing the monophyly of
these taxa (the Ophthalmotilapia assemblage), and the intragroup relationships of its
constituent genera, he was unable to recognize a sister-group for the whole assemblage. He
did, however, suggest that among the endemic Tanganyika genera, Aulonocranus,
Xenotilapia, Callochromis and Cardiopharynx share some of the derived features
characterizing the Ophthalmotilapia assemblage (Liem, 1981 : 206; 208).

My interest in these species, and the Ophthalmotilapia lineage, stems from my current
research into the levels of relationship existing between the endemic cichlid genera of Lakes
Victoria, Malawi and Tanganyika (Greenwood, 1979; 1980). Using information acquired in
this search, it seemed that Liem's concept of the Ophthalmotilapia assemblage could be
extended to include several other Tanganyika taxa, including those suspected of such
relationship by Liem. It was also apparent that the group characters for the assemblage
should be reviewed in the light of more extensive outgroup comparisons than were employed
originally.

Finally, my interest was aroused by what seemed to be the unusually clear light that some
members of the Ophthalmotilapia assemblage could throw on the longstanding and often
intractable problem of homoplasy and its effects on hypotheses of relationship amongst
African cichlid fishes.

Like Liem, I have been unable to identify a sister-group for the Ophthalmotilapia
assemblage from amongst the Tanganyika cichlids. A very tentative suggestion can be made,
however, for a possible sister-group relationship between the assemblage and certain
members of the Lake Malawi flock.

Material examined

Dissections were made of the dorsal gill-arch musculature in one, or usually 2, specimens of
each genus now included in the Ophthalmotilapia assemblage (see p. 278). The specimen of
Asprotilapia leptura (BMNH 1906.9.6: 157) was that used by Liem (1981) but the jaw
muscles of the left side were freshly dissected.

The nature of the gut and its coiling pattern were checked in several specimens of each
Ophthalmotilapia assemblage species (except Asprotilapia leptura where only the type and
the specimen noted above could be used).

Jaw and dorsal gill-arch muscles were dissected in unregistered specimens of Astatotilapia
elegans and in A. burtoni.

All available dry skeletal material in the BM(NH) collections was examined, in particular
that prepared for the revisions of the Lake Victoria, Edward-George, Kivu, and Turkana
haplochromine species (see Greenwood, 1980). Additional material, prepared for this
paper, and alizarin transparencies not previously listed, are given below. The taxa are
first grouped geographically, and then alphabetically, within the categories: Dry skeleton
(DS) and Alizarin transparency (AT).

Lake Tanganyika

DS:

A sprotilap ia leptu ra 671

Aulonocranus dewindti 1960.9.30 : 4629-641

Callochromis macrops 1906.9.8: 178

Cardiopharynx schoutedeni 1950.4.1. : 1854-81; 1960.9.30 : 1647-56

Cyathopharynxfurcifer 1900.9.8 : 25 1 ; 148; 1950.4. 1 : 1 7 14^7

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES

251

Cunningtonia longiventralis
Ectodus descampsi
Eretmodus cyanostictus
Grammatotria lemairei
Lestradea perspicax s tappers i
Limnochromis auritus
Limnochromis leptosoma
Lobochilotes labiatus
Neotilapia tanganicae
Ophthalmotilapia boops
Ophthalmotilapia ventralis
Perissodus microlepis
Perissodus paradoxus
Petrochromisfamula
Petrochromisfasciolatus
Petrochromis polyodon
Simochromis babaulti
Simochromis curvifrons
Simochromis dardennei
Simochromis diagramma
Simochromis loocki
Trematocara marginatum
Trematocara unimaculatum
Tropheus moorei
Xenotilapia boulengeri

AT:

Astatotilapia burtoni
Aulonocranus dewindti
Callochromis macrops macrops
Callochromis macrops melanostigma
Cardiopharynx schoutedeni
Ctenochromis horei
Cunningtonia longiventralis
Cyathopharynx furcifer
Ectodus descampsi
Eretmodus cyanostictus
Grammatotria lemairei
Hemibates stenosoma
Lamprologus brevis
Lamprologus cunningtoni
Lamprologus elongatus
Lamprologus fasciatus
Lamprologus tetracanthus
Lamprologus werneri
Lestradea perspicax
Limnochromis abeelei
Limnochromis auritus
Limnochromis dhanisi
Limnochromis otostigma
Limnochromis pfefferi
Limnochromis permaxillaris
Ophthalmotilapia boops
Ophthalmotilapia ventralis
Perissodus hecqui
Perissodus microlepis
Perissodus paradoxus
Petrochromisfasciolatus
Petrochromis polyodon

1950.4.1

1265-1281

1906.9.8

194; 1950.4.1

1950.4.1

5171-82; 693

1950.4.1

3758-3785

1960.9.3C

I: 1553-1557

1906.9.6

1950.4.1

554-566; 567

3066-67

1900.12.13:35
1960.9.30: 1720-1724

1906.9.8 : 144
Uncatalogued
1906.9.8. : 267
1950.4.1 : 7642-52
1960.9.30: 1368-71; 1372-75

1 898.9.9 : 66; 1 950.4. 1 : 7608-6 1 1 ; uncatalogued
Uncatalogued

1955.4.12 : 47-66; uncatalogued

1906.9.8 : 244; uncatalogued (4 specimens)

1906.9.8: 217; uncatalogued

1950.4.1 : 7674-7701; 7702-7728

1960.9.30:4835^850

1906.9.6: 119

1950.4.1 : 907-67; uncatalogued

1961.11.22:290-293

1960.9.30:2415-33

1950.4.1 : 4695-775; 4642-656

1960.9.20:2821-2823

1960.9.30:2845-2859

1960.9.30: 1574-1615

1960.9.30:2526-28

1960.9.30: 1896-1907

1960.9.30: 1792-1802

1961.11.22: 113-119

1950.4.1 : 5171-5182

1960.9.30 : 3317-30; 3276-79; 3208-21

1961.11.22:976-989

1960.9.30:7181-7225

1950.4.1 : 6701-6707

1960.9.30:6851-6860

1950.4.1 :7075

1960.9.30:7309-7336

1976.5.21 : 46-65

1960.9.30: 1468-84

1961.11.22:56-58

1960.9.30: 1981-85

1960.9.30:2001-04

1960.9.30: 1989-97

1960.9.30: 1923-26

1961.11.22:41-46

1960.9.30: 1716-18; 1720-24

1960.9.30: 1689-94

1960.9.30:6364-69

1960.9.30:6386-91

1960.9.30:6468-6482

1960.9.30: 1392-93; 1394-96; 1390

1960.9.30: 1359-63

252

Simochromis curvifrons
Simochromis dardennei
Simochromis diagramma
Simochromis loocki
Telmatochromis temporalis
Trematocara caparti
Trematocara kufferathi
Trematocara marginatum
Trematocara nigrifrons
Trematocara stigmaticum
Trematocara unimaculatum
Tropheus moorei
Xenotilapia boulengeri
Xenotilapia melanogenys
Xenotilapia ochrogenys
Xenotilapia sima
Xenotilapia tenuidentata

Lake Malawi
DS:

Astatotilapia calliptera
Aulonocara nyassae
Aulonocara rostrata
Chilotilapia rhoadesii
Corematodus shiranus
Corematodus taeniatus
Cyathochromis obliquidens
Cynotilapia afra
Docimodusjohnstoni
Genyochromis mento
Gephyrochromis lawsi
'Haplochromis ' ahli
'Haplochromis ' annectens
'Haplochromis ' argyrosoma
'Haplochromis ' atritaeniatus
'Haplochromis ' auromarginatus
'Haplochromis ' breviceps
'Haplochromis ' caeruleus
'Haplochromis ' chrysonotus
'Haplochromis ' dimidiatus
'Haplochromis ' ericotaenia
'Haplochromis ' euchilus
'Haplochromis ' eucinostomus
'Haplochromis ' fuscotaeniatus
'Haplochromis' guentheri
'Haplochromis ' intermedium
'Haplochromis ' johnstoni
'Haplochromis ' kirkii
'Haplochromis ' kiwinge
'Haplochromis ' labifer
'Haplochromis ' labridens
'Haplochromis ' lateristriga
'Haplochromis ' lepturus
'Haplochromis ' longimanus
'Haplochromis ' macrostoma
'Haplochromis ' marginatus
'Haplochromis ' moorii
'Haplochromis ' nototaenia
'Haplochromis ' ornatus

P. H. GREENWOOD

1961.11.22:2-8

1960.9.30: 1061

1960.9.30: 1170-1174; 1188-91

1950.4.1 : 7702-28

1960.9.30:6531-6538

1961.11.22:703-721

1961.11.22:883-910

1960.9.30:4881-90

1961.1 1.22 : 693-703; 1960.9.30 : 4990-5019

1960.9.30:5143-171

1961.11.22:519-528

1961.11.22: 13

1961.11.22:225

1950.4.1 : 4035-40; 1960.9.30 : 3449-455

1960.9.30:3820-855

1961.11.22:208-211

1960.9.30:7998-8014

1893.11.15:4

1935.6.14: 2259-63; 681. 5A

681. 5A

681.2; 1935.6.14:2103-211

68 1.4 A

681.4B;681.4C

1935.6.14 : 282-295; 681. 12A : 681. 12B

1893.1.17: 8 (syntype)

681.3

1965.10.26:24-29

1965.11.2: 14-22(paratypes)

1935.6.14: 1469-71

1935.6.14:847-52

1935.6.14: 1657-61

1935.6.14: 1426-9

1935.6.14: 1476-78

1935.6.14:870-72

1935.6.14: 1267-69

1935.6.14: 1823-32

1935.6.14: 1154-71

1935.6.14:2405-2411

1972.9.13:70

1962.10.18: 1-10

1935.6.14:494-95

1921.9.6: 154-62

1972.9.13:91-94

1935.6.14:523-32

1935.6.14:953-62

1935.6.14: 1031^0

1972.9.13:77-81

1935.6.14:991-1000; 1001-05

1935.6.14: 1209-18

1935.6.14: 1340-56

1972.12.20:35-78

1935.6.14:605-7

1935.6.14:769-77

1935.6.14: 1692-1700

1935.6.14: 1378-84

1972.12.18:31-33

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES

253

'Haplochromis ' orthognathus
'Haplochromis ' placodon
'Haplochromis ' pleurotaenia
'Haplochromis ' polystigma
'Haplochromis ' quadrimaculatus
'Haplochromis ' prostoma
'Haplochromis ' rhoadesii
'Haplochromis ' rostratus
'Haplochromis ' semipalatus
'Haplochromis ' spilonotus
'Haplochromis ' spilorhynchus
'Haplochromis ' subocularis
'Haplochromis ' tetrastigma
Hemitilapia oxyrhynchus
Labeotropheus fuelleborni
Labidochromis vellicans
Labidochromis zebroides
Lethrinops auritus
Lethrinops lethrinus
Lethrinops longimanus
Lethrinops parvidens
Lethrinops praeorbitalis
Melanochromis melanopterus
Melanochromis vermivorous
Petrotilapia tridentiger
Pseudotropheus fuscus
Pseudotropheus livingstoni
Pseudotropheus lucerna
Pseudotropheus macrophthalmus
Pseudotropheus tropheops
Pseudotropheus williamsi
Pseudotropheus zebra
Trematocranus microstoma
AT:

Astatotilapia calliptera
Aulonocara nyassae
Lethrinops lethrinus

Elsewhere
DS:

Astatotilapia bloyeti
Astatotilapia nubila
Chromidotilapia batesii
Chromidotilapia kingsleyae
Oreochromis niloticus
Tilapia rendalli
Tilapia zilli
AT:

Astatotilapia bloyeti
Astatotilapia macropsoides
Oreochromis niloticus

Radiographs used in this study were:
Lake Tanganyika

Asprotilapia leptura
Aulonocranus dewindti
Callochromis macrops macrops

1973.3.26: 189; 1969.3.11 : 19

1935.6.14: 1736^15

1935.6.14:911-16

1935.6.14:433-37

1935.6.14: 1960-69

1962.10.18 : 59-71; 1979.1 1.26 : 5-9

681T

1935.6.14:549-54

1956.6.12:9-10

1969.3.11 : 11-14

1935.6.14: 1260-^

1935.6.14: 1180-89

1935.6.14: 1556-66; 1567-77

1906.9.7 : 39

1972.8.11 : 3-5; 681. 11

1965.10.26: 14-21

1981.1.9: 102-1 06 (paratype)

1930.1.31 : 84-86

1930.1.31 : 150-4; 1906.9.7:35

1969.3.11 : 20-23

1935.6.14:2070-73

696J

1935.6.14 : 303 (syntype); 1971.9.13 : 32-36

1935.6.14: 307-16 (syntype)

1981.2.2: 212-20; 681.9

1965.10.25: 131^1

1935.6.14: 128-30

1935.6.14: 165-9 (syntype)

Uncatalogued

1965.10.25: 1 15-24; 681. 8C

1965. 10.25: 20-26; 68 1.8B

1935.6.14: 135-40; 681.8A

1935.6.14:2232-6

1966.7.26: 17-42
1935.6.14:2259-63
1930.1.31 : 109-118

1961.12.1 : 341-353

1911.3.3: 148

1912.6.29:4

1912.4.1 :526; 1908.5.30: 186

662 D; Uncatalogued

1906.9.7:32

1907.12.2:3767

Uncatalogued
Uncatalogued
1907.12.2:3533-534

1906.9.6: 156-157 (FW 677)
1950.4.1 : 4843-93 (FW678)
1950.4.1 : 3258-3 12 (FW683)

254

Callochromis macrops melanostigma
Callochromis pleurospilus
Cardiopharynx schoutedeni
Cunningtonia longiventralis
Cyathopharynxfurcifer
Ectodus descampsi
Grammatotria lemairei
Les traded perspicax
Ophthalmotilapia hoops
Ophthalmotilapia ventralis
Xenotilapia boulengeri
Xenotilapia melanogenys
Xenotilapia ochrogenys
Xenotilapia ornatipinnis
Xenotilapia sima

Lake Fwa

Callopharynx microdon
Cyclopharynxjwae
Neopharynx schwetzi

P. H. GREENWOOD
1960.9.30 : 2882-96 (FW683)

1940.4.1

1960.9.30: 1574-1615 (FW674)

1950.4.
1950.4.

3458-662; 1920.5.25 : 152-53 (FW682)

1 282-86 (FW676)

1605-37; 1906.9.8 : 249-251 (FW673)

1 96 1.1 1.22: 76-87 (FW677)
1950.4.1 3703-3727 (FW684)
1950.4.1 153 1^16 (FW676)
1960.9.30: 1 720-24 (FW675)
1950.4.1 1291-1465 (FW675)
196 1.1 1.22: 290-93 (FW679)
1960.9.30: 3419-48 (FW681)
1950.4.1 : 4047-1 36 (FW679)
1960.9.30 : 3685-728 (FW681)
1961.11.22: 1 90-202 (FW680)

MRAC71300(FW671)
MRAC71301(FW671)
MRAC 71290, 76201 (FW671); 71291-99 (FW672)

A review of group characters for the Ophthalmotilapia assemblage

As originally defined by Liem (1981), the Ophthalmotilapia assemblage1 comprised the
following genera: Asprotilapia Blgr (1901), Ectodus Blgr (1898), Lestradea Poll (1943),
Cunningtonia Blgr (1906) and Ophthalmotilapia Pellegrin (1904). Ophthalmochromis Poll
(1956) was shown by Liem (1981 : 210) to be a synonym of Ophthalmotilapia, a decision
with which I fully agree.

Liem's concept of the OA, and his grounds for considering it a monophyletic group, were
based on eight uniquely congruent apomorphic characters present in all the constituent taxa
(Liem, 1981 : 207-208). With one possible exception, however, Liem believed that none of
these characters is an autapomorphy for the group (Liem's character 2, the outline shape of
the palatine bone, is the exception).

The apomorphic status of the eight group-characters was justified by Liem (198 1 : 205) on
the grounds of their being derived relative to the character state found in various generalized
taxa (such as Astatotilapia burtoni and A. elegans) and in other taxa from Lake Tanganyika.

I have been able to extend Liem's outgroup comparisons to include the cichlid genera of
Lakes Malawi, Victoria and Edward, taxa from various river systems and their associated
small lakes, and additional genera from Lake Tanganyika itself. Wherever possible, several
species of a genus were examined.

The review of the eight OA group-characters which follows takes this extra material into
account. It should be noted, however, that the new members of the 0A (see p. 262) are, for
the purposes of the review, not treated as elements of the assemblage. Thus, unless otherwise
indicated, all references to the OA in this section of the paper are to the assemblage as
originally defined by Liem.

Since the sequence in which group apomorphies are treated here differs somewhat from
that used by Liem (1981 : 207), the number he gave to a character is given, in square
brackets, after the number used in this review. The same convention is followed throughout
the paper.

(1) [1]. The entopterygoid is widely separated from the palatine (see Liem,
1981: 205-206, 207; fig. 4; and Figs 1 A-F below).

1 For the sake of brevity, Liem's shorthand term for the assemblage, the OA, will be used in this paper as well.

THE OPHTHALMOTILAP1A ASSEMBLAGE OF CICHLID FISHES

255

Scales '3 mm

Fig. 1 Suspensoria (left) of: A, Callochromis macrops melanostigma; B, Xenotilapia
tenuidentata; C, Cyathopharynx furcifer; D, Cyathopharynx schoutedeni (see p. 282); E.
Grammatotria lemairei; F, Aulonocranus dewindti.

As far as I can determine, this character, except for its occurrence in the Malawian genus
Lethrinops (and those species from Tanganyika which I propose to include in the 6>A) is
unique to the Ophthalmotilapia assemblage.

The gap is created, in part, by a reduction in the depth of the entopterygoid, and in part by
a reduction of its extension above the quadrate. As a. result of these proportional and
positional changes, the anterior entopterygoidal margin lies below the level of the palatine's
posterior margin, and below the upper part of the ectopterygoid as well (with both of which
bones it would otherwise articulate). The space between the three bones (that is, the 'gap') is
actually filled by dense, translucent connective tissue.

256 P. H. GREENWOOD

It could be argued (and has been argued by Barel, pers. comm.} that the palatopterygoid
gap is a correlate of the large and often ovoid eye characterizing all members of the OA. This
is a complex problem to resolve since the influence of eye size and shape on cranial
architecture is the result of several interacting factors, and there are few data available on the
dynamics of syncranial ontogeny. In particular we have no information on the influence of
ultimate eye size on the ontogeny of the whole suspensorium, of which the palatine and
entopterygoid bones are but a part (see below p. 257).

Taking the maximum diameter of the eye (expressed as a proportion of head length) as a
measure of eye size it is difficult to find a simple correlation between that ratio and the nature
of the palatine-entopterygoid articulation. For example, in Hemibates, Trematocara,
Reganochromis, certain ' 'Limnochromis'' species and in Perissodus (all from Lake
Tanganyika) the eye is as large as that in members of the OA, and the eye in Trematocara is
as markedly ovoid as it is in any member of the OA. Yet, in none of these species is there a
palatopterygoid gap. (Recently, Poll (1981) has revised the genus Limnochromis which he
now divides into four genera. Since several of the older references in the literature are just to
the genus Limnochromis, I have adopted the convention of referring to the taxon as
'Limnochromis', except when reference is made to species retained by Poll (1981) in that
genus.)

Conversely, in many species of the Malawian genus Lethrinops (Fig. 15) there is a
palatopterygoid gap (albeit a less extensive one than in some though not all OA species), but
the eye is smaller than in members of the OA.

Since, amongst the taxa with enlarged eyes only the OA species have developed a
palatopterygoid gap, the gap would seem to be a shared derived character for the assemblage.

That argument would hold even if future research shows the 'gap' to be one of several
correlated features associated with the evolution of a large eye. The presence of a gap in
Lethrinops (which does not have enlarged eyes), on the other hand, fails to support any
argument suggesting that eye size and a palatopterygoid gap are necessarily correlated.

(2) [3]. The slender hyomandibula has a long symplectic process and no, or a very
reduced, hyomandibular flange.

On the basis of extensive outgroup comparisons I cannot agree with Liem on the relative
length of the symplectic process. In fact, most OA species have a process which is no longer
than that in Astatotilapia burtoni, A. elegans (or in other Astatotilapia species), or that in
other Tanganyika genera (Fig. 2). Unfortunately this character is difficult to quantify and is
one affected by the level to which the anterior margin of the hyomandibular flange is
produced ventrally. To this extent the apparent length of the process is an optical illusion. It
is also affected by the stoutness of the flange which, in this region of the bone, is easily
damaged; if partially broken its absence may add to the apparent length of the symplectic
process.

As compared with the hyomandibular flange in many taxa (both within and outside Lake
Tanganyika) that in all OA species is reduced. But, I would question that it is ever absent,
even in those species with the greatest reduction in flange area.

A reduction in flange area comparable with that found in OA species does occur in several
other species as well, and these are mostly taxa with large eyes. Thus, amongst the Lake
Tanganyika endemics a reduced OA-like flange is found in Hemibates, Trematocara,
Haplotaxodon, Grammatotria, Callochromis, Xenotilapia, Cardiopharynx, Cyathopharynx
and Aulonocara. In contrast, Reganochromis calliurus, whose eye is as large as that in some
OA species, has a moderately well-developed flange which is larger than that in any OA
species.

The hyomandibular flange is not reduced in Lethrinops (Lake Malawi) nor in any of the
species examined whose modal eye size (i.e. eye diameter as a proportion of head length) is
less than that of any OA species.

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES

257

i mm

Fig. 2 Hyomandibula (right), in lateral view, of: A, Ectodus descampsi; B, Astatotilapia

macropsoides.

There is thus some suggestion that a reduction in hyomandibular flange area may be
correlated with a large eye size. This correlation could result, ontogenetically, from the
developing eye preempting some of the space which otherwise would be available for the
levator arcus palatini muscle whose origin is principally from the flange. It is noteworthy
that in those species with a reduced flange, the levator arcus palatini has, relatively speaking,
a reduced volume, and that its origin has shifted largely to the metapterygoid (Liem,
1981 : 19 5-6; personal observations).

Incidentally (pace Liem, 1981 : 207), in three of the four Oreochromis niloticus specimens
examined, hyomandibular flange area is proportionately equivalent to that in the OA
species; in the fourth specimen it is noticeably larger. The two smallest O. niloticus (ca. 42
and 52 mm standard length) have the narrowest flanges of the four specimens examined,
again suggesting that flange area may be related to eye size since the smallest fishes have
proportionately the largest eyes.

(3) [5] The vertical depth of the metapterygoid is shallow.

It is difficult to assess the value of this character as an indicator of phyletic relationships.
The metapterygoid is noticeably shallow in all the OA species recognized by Liem, and in
those which I would add to the assemblage. However, an equally shallow or even shallower
metapterygoid is known from several Tanganyika taxa (for example, in species of
Lamprologus, Reganochromis, Trematocara, 'Limnochromis', and also in Perissodus
hecqui, P. microlepis and P. eccentricus). In some of these species the eye is large (equivalent
in size to those of the OA species), in others it is smaller. From this information it is
impossible to decide whether a shallow metapterygoid is a correlate of eye enlargement, a
homoplastic feature, or one which might be indicative of phyletic relationship at a higher
level than that under consideration.

(4) [2] The posterior and dorsal margins of the palatine form a 90° angle. Elsewhere,
Liem (1981: 206) expands this statement and notes that The 90° posterodorsal angle
surrounding a posterodorsal expansion of the palatine is not found in any other
Tanganyika cichlids and deviates from the condition in generalized cichlids (e.g.
Astatotilapia burtoni, Liem and Osse, 1975 and A. elegans, Barel, et al, 1976).'

258 P. H. GREENWOOD

Liem (1981 : 208) places particular importance on this character, considering it as possibly
the only autapomorphic feature of the assemblage.

My observations on the OA species indicate that the posterodorsal angle is not always
rectangular and that it shows some intra- and interspecific variability. Also, I would contest
the statement that the OA type of palatine shape is not found in other Tanganyika species. It
does occur, for example, in Limnochromis abeelei, and is closely approached in other species
as well. Furthermore it occurs in species outside the lake (e.g. Astatotilapia macropsoides
[Lakes Edward and George] and in some Lethrinops species [Lake Malawi]).

I would agree, however, that the overall type of palatine morphology in OA species is
relatively uncommon amongst African cichlids, combining as it does a straight or virtually
straight posterior margin meeting the dorsal margin at, or almost at, an angle of 90°, and with
a posteriorly expanded body of the bone. In combination these features give to the elongate
vertical part of the bone a distinctive and near rectangular outline.

Like character (3) [5], the palatine shape is difficult to evaluate as an indicator, or potential
indicator, of close phylogenetic relationship. However, since a similarly shaped bone is
rarely present amongst taxa other than members of the OA (and in those genera where it does
occur it is not manifest by all member species), and since non-OA taxa with this type of
palatine are not closely related to the OA, it might well indicate a shared common ancestry
for the Ophthalmotilapia assemblage.

(5) [4]. The anterior margin of the pterosphenoid is notched.

This character is so widely distributed amongst African cichlids (including the most
generalized taxa) that it cannot be treated as an apomorphy at this level of phyletic analysis.

That the notch, or rather the tongue which delimits one aspect of the notch, has not been
commented upon before, or been shown in figures of cichlid neurocrania, may well be due to
its fragility and hence loss during preparation of the skull. (It is of course absent in some
species and is not invariably present in all members of a genus.) Also, the process can be
rather small and is then virtually invisible unless the skull is carefully cleaned of connective
tissue.

Pace Liem (1981 : 207), the ligament connecting the sclerea with the pterosphenoid or its
notch is present in generalized cichlids. In fact, it is present in all the cichlids I have
dissected, and also in several other teleostean groups as well (including non-percoids).

(6) Liem's two myological characters, viz. [7] the transversus dorsalis is reduced, and [8]
the obliquus posterior is enlarged, may be taken together.

At the outset of any discussion it must be made clear that neither character is easily
assessed, partly because of insufficient comparative data from outgroups, and partly because
they are not readily quantified and are thus particularly subjective.

In the discussion which follows, Asprotilapia is excluded from any generalizations about
the transversus dorsalis in the OA; Asprotilapia does show unequivocally clear-cut
reduction of the transversus dorsalis anterior and the posterior head of the muscle is not
developed at all.

From my observations on dorsal gill-arch muscles in OA taxa, and in other cichlids from
Tanganyika and elsewhere (including generalized species such as Astatotilapia elegans, and
'derived' taxa such as Bathybates, Hemibates and Trematocara (see also Stiassny, 1981), I
would not consider the condition of the transversus dorsalis or the obliquus posterior in OA
species to be trenchantly distinct. For example, although Liem (1981 : 207) considers the
transversus dorsalis complex in OA species to be reduced relative to that in A. elegans, and
the obliquus posterior to be hypertrophied, I could see no obvious differences when making
the same comparisons.

That there are differences in the extent to which these and other dorsal gill-arch muscles
are developed amongst African cichlids cannot be denied (see for example Liem, 1973; Liem
& Osse, 1975; Stiassny, 1981). But, the differences are rarely trenchant and in some cases

THE OPHTHALMOT1LAPIA ASSEMBLAGE OF CICHLID FISHES 259

(including manifestly trenchant ones) are the result of environmentally induced individual
variations (see Liem & Osse, 1975 : 442, fig. 11; for environmental effects, see Greenwood
1965).

Thus, until considerably more comparative data are available, and until some means of
quantifying apparent differences is employed, the use of relative muscle size would seem to
be of very limited value, and could even be misleading. For those reasons I would not use
either of the muscle characters in attempting to unravel the phylogeny of the OA (except, as
noted earlier, with regard to Asprotilapia; see below, p. 263).

(7) [6] The operculum has a distinct auricular process.

Although Liem (1981 : 207) notes that a well-developed auricular process occurs on the
operculum in several taxa, it is only in Perissodus hecqui, 'Limnochromis' dhanisi and the
six genera now included in the OA (see p. 262) that I would consider the process equivalent
to that found in the OA species. In all members of the assemblage, the opercular process,
although interspecifically variable in form and size, is always a noticeable feature of the
bone. That fact, coupled with the infrequent occurrence of a distinct process amongst other
genera (and its mosaic interspecific distribution in those taxa), would seem to enhance its
value as an indicator of monophyletic origin for the OA.

In brief, of the eight supposedly apomorphic characters cited by Liem as suggesting a
monophyletic origin for the OA, only three would seem to fulfil the necessary requirements
for such features, and then mainly because of their unique congruence in the species con-
cerned. The characters, as numbered above, are: the palatopterygoid gap (1), the morphology
of the palatine bone (4), and the presence of an auricular process on the posterodorsal
margin of the operculum (7).

The remaining characters (i.e. 2, 3, 5 & 6) are either of no value, are possible homoplasies,
or cannot be fully evaluated within the scope of our present knowledge.

There are, however, two other characters noted by Liem, and used by him at a different
level of universality (the intragroup level), which I consider to be group apomorphies for
the whole assemblage. These are:

(8) [15] The morphology of the lachrymal (1st infraorbital) bone.

The lachrymal in members of the OA has a very distinctive appearance (see Liem, 1981,
fig. 5; and Figs 3A-H), one which, apparently, is not replicated in any other African cichlid.
It differs from the generalized condition (as seen, for example, in Astatotilapia macropsoides,
Fig. 3J) in its overall protraction and relative shallowness. Because the anterior portion is
noticeably deeper than the posterior part, the bone has almost the appearance of a short but
deep handle extending from its expanded and near rhomboidal anterior region (Figs 3A-H);
although the anterior region is much deeper than the posterior part, it is by no means as
expansive as it is in the majority of African cichlids.

An elongate lachrymal occurs in a few other taxa (e.g. certain 'Limnochromis' species; Fig.
31) but here the bone is uniformly protracted and so lacks the contrast between its shallower
posterior third to half and the deeper anterior part, which is so characteristic of the OA type
lachrymal. Also, in these non-OA taxa with an elongate, or relatively elongate lachrymal,
the dorsal margin of the bone is but slightly concave, whereas in the OA species it is
markedly so.

The anterior margin of the lachrymal is straight or very slightly concave, its anteroventral
angle produced into a slight but distinctive peak (which is lacking in most species with an
elongate lachrymal but is present in some, e.g, 'Limnochromis' permaxillaris and 'L'.
pfefferi).

When the bone is in situ its anterior margin slopes upwards at an angle of 50°-60° to the
horizontal (the 'modal' slope in African cichlids would seem to be one close to the
horizontal, but there are several and apparently unrelated species where the slope is between
45° and 60°).

260

P. H. GREENWOOD

Fig. 3 Lachrymal (left), in lateral view, of: A, Cyathopharynx furcifer; B, Callochromis macrops
melanostigma; C, Xenotilapia tenuicaudata; D, Xenotilapia boulengeri; E, Grammatotria
lemairei; F, Cyathopharynx schoutedeni (see p. 282); G, Asprotilapia leptura; H, Aulonocranus
dewindti: I, Limnochromis auritus; J, Astatotilapia macropsoides.

Liem's figure of the OA species Cunningtonia longiventralis (and his comments on the
bone, Liem, 1981 : 206, fig. 5C) represents an unusual condition in that species since the
anterior lachrymal margin is shown as markedly concave and aligned almost horizontally. In
all 12 specimens I examined, the orientation of the bone and the shape of its anterior margin
(including the anteroventral peak) are typically of the OA type (see Fig. 4).

There are, with very few individual exceptions, six lateral line canal pores in the
lachrymal of OA species (but see p. 263 below). The modal number of these pores in all
African cichlids is five; the occasional departure from that number seems to be attributable
to individual variability. Thus, both in its outline shape (including the anteroventral peak)
and in having six lateral line pores, the lachrymal appears to be a unique apomorphic feature
for the OA.

Liem (1981 : 208) used the presence of an anteroventral peak on the lachrymal as a
synapomorphy differentiating Ectodus, Lestradea, Ophthalmotilapia and Cunningtonia
from Asprotilapia which, by implication, lacked this process. In the three specimens of
Asprotilapia leptura (the sole species) I examined, a typical OA peak is present and the
outline shape of the bone also conforms with that of other OA species (see Fig. 3G).

THE OPHTHALMOT1LAPIA ASSEMBLAGE OF CICHLID FISHES 261

omm

Fig. 4. Cunningtonia longiventralis, left lateral view of lachrymal in situ.

(9) [9]. The presence on the anguloarticular bone of a well-developed, anteroposteriorly
aligned fossa for the insertion of the adductor mandibulae muscle A2.

This well-developed fossa is noted by Liem (1981 : 195) in his anatomical description of
Ectodus descampsi, and is illustrated in the six species depicted in his figure 4. Liem did not,
however, use the feature as a major apomorphy for the OA as a whole. Indeed, he used the
presence of an extensive fossa in Asprotilapia as an autapomorphic character for that genus
(Liem, 1981 : 208).

In all <9A species the fossa is clearly defined, and is limited anteriorly by a prominent,
near-vertically aligned ridge on the anguloarticular. The principal surface for muscle
insertion is situated on the lateral aspect of the bone, and is thus unlike the generalized
condition where it lies on and across the bone's posterior margin. The insertion face, and
hence the area of the fossa, varies in size amongst members of the OA. It is largest in
Asprotilapia, smallest in Cunningtonia, with the other species occupying various inter-
mediate positions in the range. Parenthetically, it may be noted that amongst the species I
would now include in the 6>A, the fossa is small in Cyathopharynx, of intermediate size in
Xenotilapia and Grammatotria, and largest in Callochromis.

Amongst the outgroup taxa examined, an 0A type fossa is found only in Lethrinops (Lake
Malawi), Trematocara (Lake Tanganyika), Chromidotilapia batesi and C. kingsleyae (West
Africa) and, in a poorly developed state, in the following Lake Malawi 'Haplochromis'
species 'H. ' prostoma, 'H. ' johnstoni, 'H. ' breviceps and 'H. ' tetrastigma. (For the use of the
name 'Haplochromis' see Greenwood [ 1 979 : 3 1 7]).

In all other outgroup taxa examined the adductor mandibulae A2 inserts along the some-
what medially expanded posterior margin of the anguloarticular.

There is no obvious evidence to suggest a recent common ancestry shared by the O\ and
the Chromidotilapia species, nor one between any of the Lake Malawi 'Haplochromis' and
either the OA or the Chromidotilapia species.

262 P. H. GREENWOOD

In the current state of our knowledge one can be less certain about making a similar state-
ment with respect to the OA and either Trematocara (also from Lake Tanganyika) or the
Malawian genus Lethrinops. Thus a suspended judgement only can be given on whether the
presence of an OA-type fossa in these three taxa is a homoplasy, or whether it is a
synapomorphy for a group of higher universality than the one under discussion (see also
p. 257).

Because the fossa is present in all OA species (including the new additions, see below) and
because it is congruent with other apomorphic features shared by them, it can, I would con-
sider, be taken as further evidence for the monophyly of the lineage.

To summarise this review of group characters in the Ophthalmotilapia assemblage (as
defined by Liem, 1981), the congruent apomorphic features are:
(i) The presence of a palatopterygoid gap (see p. 254)
(ii) The morphology of the palatine bone (see p. 257)
(iii) The presence of an auricular process on the opercular bone (see p. 259)
(iv) The shape of the lachrymal bone (1st infraorbital); see p. 259)
(v) The presence of a well-defined, laterally placed fossa for the insertion of the A2
adductor mandibulae muscle on the anguloarticular bone (see p. 261).

The Ophthalmotilapia assemblage reconsidered

On the grounds of all their constituent species sharing the five features listed above, and
because none possesses any feature which might suggest other relationships, six further
genera can be included in the Ophthalmotilapia assemblage (see Figs 1,3, 10 and 1 1).

The new additions are:

(i) Xenotilapia Blgr, 1899 (type species X. sima Blgr)

(ii) Callochromis Regan, 1920 (type species Pelmatochromis macrops Blgr)

(iii) Grammatotria Blgr, 1899 (type species G. lemairii Blgr)

(iv) Cyathopharynx Regan, 1920 (type species Tilapia grandoculis Blgr; but see p. 284).
(v) Cardiopharynx Poll, 1942 (type species C. schoutedeni Poll)

(vi) Aulonocranus Regan, 1920 (type species Paratilapia dewindti Blgr)

Although not apparently relevant to the question of their phyletic relationships, it may be
noted that these six genera also share with members of Liem's original OA all the other
features discussed in the previous section (i.e. characters 2, 3, 5 & 6).

For taxonomic and biological details of these genera and their contained species, reference
should be made to Poll (1946 & 1956). Since I can find no grounds for maintaining
Cyathopharynx and Cardiopharynx as separate genera (see p. 282), all further references to
these taxa will be made under the name of the senior synonym, Cyathopharynx.

Liem (198 1 : 208) has already suggested that Xenotilapia, Callochromis and Aulonocranus
might be the sister lineage of the Ophthalmotilapia assemblage, but he felt that more
information was needed before their 'precise relationships' to the others could be
determined. His reason for making this suggestion was that all three genera share with the
OA a palatopterygoid gap and various derived features of the hyomandibula, ie characters (1)
and (2) above. That the three taxa also shared the other six and supposedly apomorphic
features originally used to define the OA, was not noted by him.

Although I would be chary of claiming that the 'precise relationships' of Xenotilapia,
Callochromis, Aulonocranus, Grammatotria and Cyathopharynx have been determined, I
would submit that an a priori case can be established for including them within the
Ophthalmotilapia assemblage itself, and not just as a sister-group to that lineage.

Before going on to consider intralineage relationships within the expanded OA, some
comments must be made about certain features in Aulonocranus and Xenotilapia.

In Aulonocranus the lachrymal has the characteristic shape of that bone in other OA
species (Fig. 3H), but it lacks the anteroventral peak; the anteroventral angle is rounded and

THE OPHTHALMOT1LAPIA ASSEMBLAGE OF CICHLID FISHES 263

so resembles the condition found in most cichlid taxa. It is possible that this atypical anterior
profile might be attributed to the greatly inflated laterosensory canals in the lachrymal of
Aulonocranus.

In most Xenotilapia species too, the lachrymal is atypical for the OA because in these
species there are, modally, five and not six openings to the laterosensory canal system (Figs
3C & D). There is, however, considerable inter- and intraspecific variation in pore number;
some species have six pores, others only four, and some individuals have a different number
of pores on each side of the head. Clearly, pore number is an unstable characteristic in
Xenotilapia. The genus also differs from all other OA taxa, and all other African cichlids I
have examined, in having the posterior opening to the lachrymal laterosensory system
positioned below and not opposite the anterior canal opening in the second infraorbital
bone.

As in Aulonocranus, the outline shape of the lachrymal in Xenotilapia is a typical OA one
(Figs 3C & D); not surprisingly, considering the number of species (11), there is rather more
variation on that basic shape in Xenotilapia than in other members of the assemblage.

Relationships within the Ophthalmotilapia assemblage

In its original form, the assemblage was divided into two major sublineages, one comprising
only Asprotilapia leptura, the other containing the four remaining genera, Ectodus,
Lestradea, Ophthalmotilapia and Cunningtonia (see Liem, 198 1 : 208 & fig. 9).

As defining features for the larger sublineage, Liem employed two supposedly
synapomorphic characters: (i) the morphology of the lachrymal, and (ii), the dominance of
the A, division of the adductor mandibulae muscle complex (Liem's characters 15 & 16
respectively).

The Asprotilapia lineage was recognized both by the absence of those features, and, more
importantly, by its having six presumed autapomorphic characters (see Liem, 198 1 : 208).

As argued above (character (8)[15], page 259), the features of the lachrymal must now be
considered an apomorphic character for the whole OA (including the new additions and
Asprotilapia itself)-

The muscle character, according to Liem, has two components. First, that the A, division
of the adductor mandibulae has become the dominant component of the complex, its cross
sectional area surpassing '. . . that of the other parts', and second, that '. . . its origin has
expanded ventrally at the expense of the adductor mandibulae part A2' (Liem, 1981: 208).

It is difficult to test the first claim adequately, and my attempts to do so failed to confirm
Liem's claims, especially if, as his statement implies, the A, division is dominant to both
the A2 and A3 divisions combined. However, the area of origin of A, in the taxon concerned
is very clearly greater than that of A2 when measured by its extent along the vertical arm of
the preoperculum (see fig. 6 in Liem, 1981).

When, however, the additional OA taxa are taken into account, the second feature shows a
continuous range of variation from a state where the origins of both A, and A2 occupy an
approximately equal depth on the vertical preopercular limb, to one where the origin of A2
is virtually excluded from that limb and thereby is almost confined to the horizontal part of
the bone. Furthermore, even within a single genus (as in Xenotilapia and Callochromis}
some species have A, and A2 with almost equal depths of vertical origin (the plesiomorph
condition in cichlids), others have the depth of A, greater than A2, and yet others have A2
with a much greater vertical depth of origin than A, (Fig. 5B). Thus there would no longer
seem to be any grounds for maintaining the unity of the Ectodus- Cunningtonia sublineage
on the basis of its myological characters.

The peculiar arrangement of the adductor mandibulae muscles in Asprotilapia still stands
as a well-defined autapomorphy for the genus. Here, division A, is markedly reduced, both
in the depth of its origin on the preoperculum, and in its overall bulk (Fig. 5A), a condition
not found elsewhere in the OA. Other features, however, suggest that Asprotilapia is closely
related to some of the newly incorporated members of the assemblage (p. 265).

264

P. H. GREENWOOD

Fig. 5 Superficial adductor mandibulae muscles (left side) of: A, Asprotilapia leptura; B,
Xenotilapia sima. AM, & AM2 : adductor mandibulae divisions 1 and 2; TAM, : tendon of
insertion for AM,.

Although a primary dichotomy within the OA cannot be made on the characters
employed by Liem, such a dichotomy can be established on differences in the length of the
gut and the manner in which it is arranged within the visceral cavity (see Figs 6 & 7).

Liem (1981 : 209; character [19]) used intestinal length to define a group of taxa
(Ophthalmotilapia, Cunningtonia and Lestraded) within the original 0A, but he did not
comment on the spatial arrangement of the alimentary tract in those species.

Within the expanded OA, the member taxa can be grouped into those with an intestinal
length less than 3 times the standard length of the body, modally 2-3-2-5 times SL, and those
with an intestinal length 3-6 times the standard length.

Species in the first group have the relatively short gut coiled into a few loops whose
arrangement is in an essentially anteroposterior direction. In contrast, species with a long gut
have the intestine much coiled and the coils are arranged in an essentially transverse
direction (see Figs 6 & 7). At first sight this transverse arrangement gives an erroneous
impression of the intestine actually being coiled around the stomach (Fig. 7).

A long and complexly coiled gut is a derived feature, occurring in several cichlid lineages.
But, since these lineages are not closely related it can be treated as a synapomorphy at the
level of universality involved here.

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES

265

» mm

Fig. 6 Alimentary tract (left lateral view) of an Asprotilapia subassemblage taxon (Grammatotria

lemairei).

»mm

Fig. 7 Alimentary tract (left lateral view) of an Ophthalmotilapia subassemblage taxon

(Ophthalmotilapia boops).

Taxa of the OA belonging to the group with a long and transversely coiled intestine are:
Lestradea, Ophthalmotilapia, Cunningtonia and Cyathopharynx - hereafter referred to as
the Ophthalmotilapia subassemblage; their interrelationships will be considered later (see p.
271).

The group with a short and longitudinally coiled intestine comprises the genera
Asprotilapia, Callochromis, Xenotilapia, Grammatotria, Ectodus and Aulonocara-
hereafter referred to as the Asprotilapia subassemblage.

Four genera in the Asprotilapia subassemblage, viz. Asprotilapia, Callochromis,
Xenotilapia and Grammatotria, share an apomorphic feature which suggests their shared
common ancestry. This character is the presence of a fully developed pharyngeal hanging
pad, with its associated modifications to the superficial anatomy of the gill-rakers; see Figs 8
&9.

The pad is an hypertrophied and well-circumscribed, forwardly directed, and turgid fold of
the buccopharyngeal tissues. It lies immediately anterior to the upper pharyngeal bones and
extends forward and downward, as a visor-like projection, for a short distance in front of the
first gill-arch. Posterolaterally the pad is fused with the thickened tissue covering the
epibranchial gill-rakers of the first gill-arch, but over most of its width the visor-like part is

266

P. H. GREENWOOD

Fig. 8 Pharyngeal hanging pad in Xenotilapia boulengeri. Left side, seen from a slightly

dorsolateral viewpoint.

Fig. 9 Ventral portions of the gill-arches, and the lower pharyngeal bone of Xenotilapia
boulengeri, viewed from above to show the nature of the gill-rakers.

separated from the buccal roof by a distinct transverse groove. This groove is open anteriorly
and laterally. In the buccal midline the left and right halves of the visor-like portion are
confluent with the buccopharyngeal roof. When the mouth is closed, and the ventral
gill-arch skeleton is adducted, the visor occludes the pharynx, leaving only a narrow channel
coincident with the medial area of confluence between the two halves of the visor and the
buccopharyngeal epithelium.

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES 267

The pharyngeal surface of the visor is thrown into a large number of broad-based but
terminally acute papillae. When the gill-arches are adducted the papillose area is brought
into close contact with the upper surface of the cerato- and hypobranchial regions of the
gill-arches. These, in turn, are covered by a greatly thickened and soft epithelium. The inner
and outer gill-rakers on the ceratobranchial of each arch are joined transversely by anvil-
shaped folds of thickened tissue so that, superficially, there appears to be but a single series of
rakers, with each raker extending across the breadth of the arch (Fig. 9).

A pharyngeal hanging pad is known from two other, and very dissimilar, African genera,
Chromidotilapia and Tylochromis, and in the South American Geophagus (see Trewavas,
1 974 : 389-392). Since there are several features strongly indicating that none of these taxa is
closely interrelated, and that none is closely related to the Ophthalmotilapia assemblage, the
repeated occurrence of a hanging pad can only be interpreted as the result of convergent
evolution. Any other explanation would be most unparsimonious. It would be equally
unparsimonious to assume that its occurrence in four of the OA taxa was the result of
independent evolution in each genus. This is particularly so since three of the four genera
share another apomorphy, a high number of caudal vertebrae in Xenotilapia, Asprotilapia
and Grammatotria, and a second derived character, the shape of the dentary, is shared by
Xenotilapia, Callochromis and Grammatotria, of which taxa Callochromis alone does not
share the vertebral apomorphy.

Thus, on the basis of their all possessing a pharyngeal hanging pad, Xenotilapia,
Callochromis, Grammatotria and Asprotilapia1 are taken to form a natural group within the
<9A. The group can be further subdivided on the distribution within its members of certain
other derived features.

Xenotilapia, Callochromis and Grammatotria all have a peculiarly shaped dentary (Fig.
10). When viewed laterally, the dorsal margin of the bone is seen to dip downwards
immediately behind the last tooth in the outer row. It continues posteriorly at this lower
level until it curves upwards to form the anterior margin of the coronoid process. The
alveolar surface is confined to that part of the bone preceding the step, behind which it is
edentulous. The dentary of Asprotilapia will be discussed below.

This type of dentary, as far as I am aware, is not found in any other cichlid from Lake
Tanganyika, or for that matter from Lake Victoria either. It is, however, closely approached
by the dentary in the Malawian genus Lethrinops and in some 'Haplochromis' species from
that lake. The significance of this similarity, and the occurrence in Lethrinops of a
palatopterygoid gap, is discussed on page 279.

Within the group comprising Xenotilapia, Callochromis and Grammatotria it is
impossible to determine which two genera are the more closely related since no clear-cut
linking synapomorphies can be recognized. It is accepted that the diagnostic 'generic'
characters for each genus are autapomorphies for that taxon. At present the trio can only be
treated as an unresolved trichotomy, but with the suggestion that further research may show
Xenotilapia and Grammatotria to be sister taxa.

Asprotilapia, the fourth member of the group, is a most distinctive taxon, in which Liem
(1981 : 208) identified six autapomorphies. These must now be reviewed in the context of
the expanded Ophthalmotilapia assemblage.

As in earlier discussions, Liem's apomorphy number is given in square brackets.

(i) [9]. The elongate, slender mandible has an expanded adductor fossa for the A2
division of the adductor mandibulae muscle.

As noted earlier (p. 261) the adductor fossa is expanded in several members of the OA,
particularly in species of the group to which Asprotilapia belongs. However, even amongst
those species the fossa is most expansive in Asprotilapia.

'Microbranchiospines are present in all four of these Tanganyika genera; in this respect they resemble Tylochromis
and differ from Chromidotilapia (see discussion in Trewavas, 1 973 : 1 7 & 1 974 : 388).

268

P. H. GREENWOOD

ADDF

Fig. 10 Dentary and anguloarticular in two species of the Asprotilapia subassemblage : A,
Grammatotria lemairei (lateral view); B & C, Xenotilapia boulengeri (lateral and ventral views
respectively). ADDF : adductor fossa. NF : nerve foramen.

1mm

Fig. 11 Left dentary and anguloarticular of Asprotilapia leptura in : A, lateral view; B, occlusal
view. In B the teeth have been restored (based on a spirit specimen), but in A only the tooth scars
are shown.

THE OPHTHALMOTILAP1A ASSEMBLAGE OF CICHLID FISHES 269

The mandible is not, in my view, especially elongate, particularly when it is compared
with that element in other members of the Asprotilapia subassemblage (cf. Figs 10 & 1 1). Its
gross morphology differs from that in Xenotilapia, Callochromis and Grammatotria since it
lacks a 'stepped' alveolar margin, and because each ramus of the jaw has a more abrupt and
stronger medial curvature towards the symphysis. Also, in Asprotilapia, immediately before
the dentary curves inwards, the alveolar surface is produced laterally so as to form a
noticeable, shelf-like overhang of the underlying ramus (Fig. 1 1).

Overall, the dentary in Asprotilapia bears a fairly close resemblance to that bone in
Labeotropheus of Lake Malawi, a resemblance enhanced by the tricuspid, slender-necked,
procumbent and movably implanted teeth present in both genera. Asprotilapia has, how-
ever, a shallower dentary, and the anguloarticular is taller and more expansive than in
Labeotropheus. Parenthetically it may be noted that Asprotilapia, like Labeotropheus, has
an enlarged and similarly shaped cartilaginous meniscus underlying the premaxillary
ascending process, and a similar fleshy medial projection overlying the broad palato-
premaxillary ligaments. Observations made from radiographs of the two species, and from
manipulation of preserved specimens, indicate that the protrusile mechanisms in the two
species are very similar. There are, however, no reasons to doubt that these similarities
should be treated as homoplasies.

(ii) [10]. The posterior head of the transversus dorsalis anterior muscle is absent.

This seems to be a clear-cut autapomorphy, but should be checked in more examples than
the single specimen available to Liem and myself.

(iii) [11]. Lateral ethmoids greatly enlarged.

This again is an apparently good autapomorphy.
(iv) [12]. Interorbital width greatly reduced.

The interorbital width is reduced in some Xenotilapia species, but in none is it as narrow
as in Asprotilapia.

(v) [13]. The reduced articular process of the premaxilla is in a more forward position.

There is considerable and continuous variation in the relative position of this process in
Xenotilapia species, and indeed within the taxa of the entire OA. It would not, therefore,
seem to be a character of particular value.

(vi) [14]. The greatly enlarged cranial condyle and the premaxillary process constitute
the bulk of the maxilla.

The maxilla of Asprotilapia is less outstanding when compared with that bone in other
members of the subassemblage, especially Xenotilapia (Fig. 12). In X. boulengeri, for
example, the process is larger than in Asprotilapia. The cranial condyle, however, is largest
in Asprotilapia and, as compared with all other <9A species, the whole bone is relatively
foreshortened.

In the context of the expanded <9A, I would consider that at least three of the
autapomorphies originally proposed (i.e. nos. i, ii and iii above) retain their validity (if, that
is, the apomorphic features of the lower jaw are interpreted as has been done here).

Although not listed as an autapomorphy by Liem (198 1), the peculiar condition of the A,
division of the adductor mandibulae muscle in Asprotilapia would seem deserving of that
status. In Asprotilapia, as compared with all other OA taxa, A, is a very short and narrow
muscle with an extremely long tendon of insertion (Liem, 1981; fig. 6; also Fig. 5), and an
area of origin much smaller in all respects than that of the A2 division. No other species in
the OA has this arrangement of the adductor mandibulae muscles.

270

P. H. GREENWOOD

1mm

Fig. 12 Right maxilla, in lateral view, of: A, Xenotilapia boulengeri; B, Asprotilapia leptura (the
damaged ventral margin of the premaxillary saddle is indicated by a broken line).

When commenting on the unusual A, muscle in Asprotilapia, Liem (1981:203)
makes particular reference to a tendon stemming from the muscle's principal tendon of
insertion, and which joins the tendinous part of adductor division A^. This emphasis might
give an impression that the vertically directed interconnecting tendon is a unique (or
unusual) feature of Asprotilapia. That is not so because the tendon is present in all cichlids
whose jaw musculature has been examined (see for example Liem & Osse, 1975: fig. 6;
Stiassny, 1981 : 80, and figs 8 & 1 1 [tA.b]; also personal observations on species other than
those studied by these authors). Asprotilapia is, however, unusual in having a discrete,
ligament-like condensation in the connective tissue between the premaxilla and dentary,
inserting on the lateral (and not the medial) face of the premaxilla.

Interestingly, despite the resemblances in lower jaw morphology between Asprotilapia and
Labeotropheus (see above p. 269), the pattern of adductor muscles in the two genera is quite
different. Labeotropheus has the typical generalized cichlid arrangement.

The various autapomorphies of Asprotilapia serve to indicate the taxon's isolation within
its group. For the moment it can only be treated as the sister taxon to the other three genera
(i.e. Callochromis, Xenotilapia and Grammatotria) combined.

The two remaining taxa in the Asprotilapia subassemblage (see p. 265), Ectodus and
Aulonocranus, are 'interrelated' only at the level of their sharing with their supposed sister-
group, Asprotilapia, Callochromis, Xenotilapia and Grammatotria, the plesiomorphic
feature of a short intestine. With one possible exception, neither Ectodus nor Aulonocranus
has any uniquely shared derived features suggestive of their recent common ancestry.

The exceptional feature concerns the marked elongation of the first, and to a lesser extent
the second pelvic fin rays in adult males. In Aulonocranus the first ray extends to about the
middle of the anal fin, and in Ectodus to a point beyond its spinous part, but never as far as
the middle of the fin. Other members of the Asprotilapia subassemblage have variously
modified relative proportions of different pelvic fin rays (see Poll, 1956) but none has the first
ray elongated to the degree found in Ectodus and Aulonocranus. The significance of this
feature is, however, somewhat questionable (see p. 272).

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES 271

In Liem's scheme (1981 : 208-9, fig. 9), Ectodus was allied with Lestradea, Ophthalmo-
tilapia and Cunningtonia (now considered to be a separate sublineage, see below)
and not with Asprotilapia. Liem's grounds for this alliance were based on Ectodus sharing
two apomorphic characters with Lestradea, Ophthalmotilapia and Cunningtonia, namely a
distinct antroventral process on the lachrymal bone, and a dominant Aj division in the
adductor mandibulae muscle complex.

As was argued above (pp. 262-263) the former character is one shared by all members of
the OA (except Aulonocranus) and the latter is a variable feature of little value as an
indicator of relationships within the OA.

Aulonocranus was not included in the original OA, although Liem (1981 : 206 & 208) did
suggest that it might be related to that assemblage.

The genus is readily identified by one outstanding apomorphy, the hypertrophy of its
cephalic laterosensory canal system, and as a probable correlate, the enlarged saccular bulla
in the basioccipital and prootic bones.

Ectodus has one autapomorphy, viz. the vertical and horizontal limbs of the pre-
operculum are of equal or almost equal length (see Liem, 1981 : 209). Liem also ranked the
enlarged saccular bulla as an autapomorphy, but the bulla is enlarged to an equal extent in
Lestradea and Ophthalmotilapia amongst members of the original OA, and in Aulonocranus
and Cyathopharynx among the new additions to the assemblage. Indeed, apart from
Callochromis, Xenotilapia and Grammatotria the saccular bulla is noticeably enlarged in all
OA species, the degree of enlargement showing a continuous increase from the condition in
Asprotilapia through to that in Aulonocranus, with Lestradea, Ectodus and Ophthalmo-
tilapia all close to Aulonocranus.

Turning now to the second lineage of the primary dichotomy, the Ophthalmotilapia
subassemblage (p. 265), one again finds difficulty in establishing intragroup relationships,
but little difficulty in recognizing autapomorphies for the constituent genera, viz. Lestradea,
Ophthalmotilapia, Cunningtonia and Cyathopharynx.

Since Lestradea lacks the various derived features shown by its congeners in the
subassemblage it would appear to be the plesiomorph sister taxon to the other three genera
combined.

Liem (1981 : 209) singled out two autapomorphies for Lestradea (i) the edentulous
anterior process of the lower pharyngeal bone is only half as long as the toothed part (his
apomorphy 20), and (ii), the body of the maxilla is stout, and has a prominent postmaxillary
process (his apomorphy 2 1 ).

I cannot agree with Liem's statement about the relative proportions of the anterior process
of the lower pharyngeal bone* The Lestradea specimens I have examined all have this
process as long as, or almost as long as the toothed part, a condition approaching that in
Ophthalmotilapia and Cunningtonia. This condition must be considered derived relative to
that in Astatotilapia and many other African cichlids. In these various taxa the edentulous
anterior process of the bone is indeed half or less than half as long as the toothed part.

The body of the maxilla in Lestradea is stout and the posterior process is prominent, but
in both features the bone does not differ from the maxilla in Ophthalmotilapia where the
process is a little less prominent. A relatively short maxilla with a prominent posterior
process is, it would seem, a common feature in the whole Ophthalmotilapia assemblage.

Cyathopharynx is readily distinguished by its autapomorphous lower pharyngeal bone
(Fig. 23), with its deeply concave occlusal surface, heart-shaped dentigerous area, and greatly
inflated body below that surface. There are, however, no synapomorphies (except group
ones) shared by Cyathopharynx and any other member of the subassemblage.

Liem (1981:209) recognized three synapomorphies which suggested to him that
Ophthalmotilapia and Cunningtonia were members of a monophyletic unit. The presumed
synapomorphies were (i) jaw teeth with long stalks, and movably implanted, (ii) the first
pelvic ray greatly elongate (Liem's apomorphies 22 & 23 respectively), and (iii) the posterior
margin of the vertical preopercular limb is straight and forms a 90° angle with the horizontal
limb.

272 P. H. GREENWOOD

The teeth in all members of the OA (sensu lato) are movably implanted, and in all species
the teeth could be described as having 'long stalks', albeit with specifically distinct but
varying degrees of slenderness. For example, in both these features the outer jaw teeth in
Ophthalmotilapia are very like those in Lestradea, but those in Cunningtonia have a much
more slender and elongate neck than do the teeth in any other OA species.

The first and second pelvic rays are elongate (much more so in males than in females) in
both Ophthalmotilapia and Cunningtonia, with, in the former, the first ray somewhat longer
than the second. But, when other species in the expanded OA are taken into account one
finds that the condition of the two rays in Cyathopharynx furcifer is like that in
Cunningtonia longiventralis, and that Aulonocranus also has elongate rays but which extend
only to the middle of the anal fin base and not to the posterior margin, or slightly beyond, as
they do in Cunningtonia and Cyathopharynx furcifer. Cyathopharynx schoutedeni has
elongate first and second pelvic rays too, but in this species it is the second ray which is the
longer and, unlike the elongate first ray in C. furcifer, it extends posteriorly only a short
distance beyond the spinous part of the anal fin.

Thus it is difficult to treat marked elongation of the first, or first and second pelvic rays as a
synapomorphy for Ophthalmotilapia and Cunningtonia. That it is a character showing
continuous variation and one that is incongruent with other apomorphies would also
preclude its use as an indicator of recent shared common ancestry for the genera exhibiting
it, namely Aulonocranus, Ophthalmotilapia, Cunningtonia and Cardiopharynx (see below).

Some comment on the spatulate, bifid tips to the first ray in males of Ophthalmotilapia
species would be appropriate here.

The feature appears to be a unique apomorphy for Ophthalmotilapia, indeed it is one of
the reasons given by Liem (1981 :210) for synonymizing Ophthalmochromis with that
genus. Spatulate tips have not been mentioned in the formal descriptions of any other
species, nor have I seen such modifications in any of the taxa, other than Ophthalmotilapia,
which I have examined. However, Brichard (1978 : 187) describes the pelvic fin in
Cyathopharynx furcifer as having '. . . a long filament tipped with a yellow double spatula'.
On page 190 of the same book he comments on 'The ventral filaments, reaching the end of
the anal fin are each tipped with a double yellow-orange spatula'. Finally, Brichard
(1978 : 148 & 149) provides two illustrations of a live individual (or individuals) showing
what certainly looks like a spatulate tip to the protracted pelvic fin rays.

Brichard is an experienced underwater-naturalist and one is hesitant to suggest he has
misidentified his material. On the other hand, in his description (Brichard, 1978 : 326) of
Ophthalmotilapia ventralis (as Ophthalmochromis ventralis) he remarks that The males . . .
have very long pelvic filaments also forked like O. nasutus, but the tips are without spatulae
(although they are pale yellow like those of O. nasutusY; bold type added. Clearly there is
some terminological confusion here since none of the male O. ventralis specimens I have
examined, or those which have been described elsewhere, lacks well-defined spatulae.

The tips of the elongate pelvic rays in Cyathopharynx are brightly coloured, and seem to
serve the same ethological function as the spatulae in Ophthalmotilapia. Perhaps the
confusion stems from that colour similarity rather than a structural one? Until spatulate
Cyanopharynx are described formally, the uncertainty will remain.

In itself, very marked elongation of the first and second pelvic rays is a derived feature (see
below), but in the context of the OA it is not clear at what level of universality it can be
recognized as a synapomorphy. For example, if used to unite Aulonocranus, Cyathopharynx,
Ophthalmotilapia and Cunningtonia, pelvic fin length would be incongruent with the group
synapomorphy of an elongate and complexly folded intestine shared by all except
Aulonocranus, which has a short and simply folded intestine. If, on the other hand, because
of its short gut Aulonocranus was taken to be the plesiomorph sister taxon of the others, then
where would Lestradea which has a long gut but short pelvic fins be placed?

The problem is further compounded by Ectodus which has a short and simply folded gut
but elongate first and second pelvic rays produced to a degree almost comparabale with those
in Aulonocranus.

THE OPHTHALMOT1LAPIA ASSEMBLAGE OF CICHLID FISHES 273

In no case are there any known synapomorphies which are uniquely congruent with
protracted pelvic fin length, and which would thereby establish a strong case for arguing that
the gut character is a homoplasy. Finally, it must be recalled that some relative elongation of
the first and second pelvic rays is of relatively common occurrence in African cichlids (see
Greenwood, 1981), and that the degree of elongation must be treated as a continuous
variable, albeit one rarely reaching the extremes found in Cunningtonia and Ophthalmo-
tilapia.

Liem's third synapomorphy (involving the shape of the preoperculum; see page 271) is
also difficult to substantiate, particularly in the context of the expanded OA. In all
constituent species of the O\ sensu law the vertical and horizontal limbs of the preopercular
bone meet at, or very nearly at, a right angle, and in all except Ophthalmotilapia and
Cunningtonia the posterior margin of the vertical limb curves inwards for a short distance
near its dorsal extremity. Because Ophthalmotilapia and Cunningtonia have the bony
flange behind the vertically aligned laterosensory canal tube narrowing imperceptibly, rather
than abruptly, the entire posterior margin of the preoperculum does give the impression of
being straight in these two species. The difference between the two types of posterior margin
is, however, very slight and is almost obliterated by the condition in Cyathopharynx. Here
the dorsal extremity of the margin is slightly indented, but less noticeably so than in most
other OA taxa.

Thus, of the three apomorphies under review, only the nature of the preopercular margin,
a not particularly trenchant character, would seem to be a synapomorphy linking
Ophthalmotilapia and Cunningtonia.

On the morphological evidence alone, it is thus impossible to hypothesize precise
intragroup relationships for the Ophthalmotilapia subassemblage, except to note that on a
simple summation of derived features Lestradea would seem to be the most plesiomorph
taxon. At the generic level the other taxa are readily identified by their particular
autapomorphies (see below).

It is possible that these currently obscure and therefore uncertain intralineage relation-
ships will be clarified when more data are available on the breeding habits of its constituent
species. Brichard (1978 : 108), for example, groups Cyathopharynx with Ophthalmotilapia
as polygamous spawners in which there is no contact between the sexes at the nest site. The
import of Brichard's statement is not really clear, and the phyletic importance of most
ethological characters still awaits evaluation. Nevertheless it is suggestive that Brichard did
single out these taxa as forming a distinctive reproductive class.

Returning now to the autapomorphic features of the genera constituting the sub-
assemblage, one finds that Ophthalmotilapia (sensu Liem, 1981 : 210) is distinguished by
the bifid spatulae in which each elongate first pelvic ray terminates, and the subdivision of
the retractor dorsalis muscle of the upper gill-arches into two distinct heads (see Liem,
1981 :201,fig.8D).

Cunningtonia has as its principal autapomorphies the nature of its oral dentition, the stout
foreshortened dentary (Fig. 1 3) and the stout premaxilla.

5mm

Fig. 13 Left dentary and anguloarticular of Cunningtonia longiventralis in lateral view.

274 P. H. GREENWOOD

Most of the jaw teeth are very slender and tall, with strongly recurved, tricuspid and broad
crowns. The teeth are arranged in wide bands over the entire alveolar surface of the
premaxilla and on the transverse part of the dentary, but on the lateral alveolar surface the
teeth are much stouter and are unicuspid.

The palatine of Cunningtonia is also unique in having its facet for articulation with the
lateral ethmoid expanded medially into a shelf-like projection. When viewed from the side,
especially in specimens prepared as alizarin transparencies, the shelf has a spine-like
appearance (see Liem, 198 1 : 2 10; apomorphy 26).

Liem considered that the symplectic in Cunningtonia was '. . . very elongate' (his
apomorphy 28), but I find that it is of virtually equal relative length in all members of the
OA.

In Cyathopharynx the principal autapomorphy is the peculiar, heart-shaped and deeply
concave dentigerous surface of the lower pharyngeal bone and, of course, the correlated
changes in the shape of the upper pharyngeal elements (see p. 288).

The nature of the apophysis for the upper pharyngeal bones in the Ophthalmotilapia
assemblage

Like Liem (1981), I have not taken into account the nature of the pharyngeal apophysis
when analysing intragroup relationships amongst members of the OA (see Greenwood,
1978, for an evaluation of this character in determining phyletic relationships; also Fryer &
lies, 1972:504^5^.).

Based on material examined personally, the distribution of apophyseal types (defined as in
Greenwood, 1978) within the two major subassemblages of the 0A is as follows:

Asprotilapia subassemblage Ophthalmotilapia subassemblage

Hap.1 Troph. Tilapia Hap. Troph. Tilapia

Callochromis Xenotilapia — — Cyatho- Lestradea

(a few spp.) pharynx

Xenotilapia Aulono-

(most spp.) cranus Ophthalmotilapia

Grammatotria* Ectodus Cunningtonia

lffap. = Haplochromis type; Troph. = Tropheus type; Tilapia = Tilapia type.

*In all specimens the apophysis is of the Haplochromis type on one side, and the Tropheus type on the other.

It is interesting that no true Tilapia type apophysis occurs amongst members of the
Asprotilapia subassemblage, but that three of the four taxa in the Ophthalmotilapia
subassemblage do have an apophysis of that type. In contrast, a Haplochromis type
apophysis occurs in three members of the Asprotilapia subassemblage but not in any taxa of
the Ophthalmotilapia subassemblage.

It must be borne in mind, however, that the Tropheus apophyseal type is structurally
intermediate between the Haplochromis and Tilapia types (see Greenwood, 1978) and that
in the Asprotilapia subassemblage certain taxa have more than one type of apophysis.
Indeed, the three specimens of Grammatotria lemairei examined have a Haplochromis type
apophysis on one side of the skull and a Tropheus type on the other.

It is also interesting to note that if the Tropheus category (of Greenwood, 1978), which
Regan did not recognize, is ignored and the taxa in that category are returned to the one in
which they were placed by Regan (1920), then the entire Asprotilapia subassemblage is of the
Haplochromis type, and the Ophthalmotilapia subassemblage becomes exclusively of the
Tilapia type.

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES 275

Such a pattern might well be taken to argue against my earlier criticisms of the pharyngeal
apophysis as an indicator of phyletic relationships at a high level of universality
(Greenwood, 1978) and that, on the contrary, African cichlids can be divided into 'Tilapicf
and 'Haplochromis"1 supralineages as suggested by Regan (1920).

If the latter argument is accepted, then the synapomorphies delimiting the Ophthalmo-
tilapia assemblage as a whole must be considered as homoplasies developed independently
in the two subassemblages recognised here. That assumption would produce a scheme of
relationships less parsimonious than the one proposed above and earlier by Liem
(1981). Also, the existence of intermediate conditions (i.e. the Tropheus type) in the
structure of the apophysis, and of other cases where a classification based on apophyseal
structure is incongruent with different and apparently synapomorphic characters (see
Greenwood, 1978; Liem & Stewart, 1976) would seem to support the rejection of apophyseal
structure as an indicator of phyletic relationships at the level proposed by Regan.

A review of other schemes of relationship suggested for members of the
Ophthalmotilapia assemblage

Regan (1920 : 52) did not present detailed arguments for his views on the interrelationships
of the Lake Tanganyika genera, which were strongly influenced by his assumption of there
being a fundamental dichotomy of African cichlids into those with a 'TilapicC type
apophysis, and those with a 'Haplochromis'' type (see above). As a result of this basic
difference in approach, it is difficult to make direct comparisons between Regan's ideas and
those put forward in this paper. However, some comments can be made on certain of Regan's
suggested relationships involving OA members and taxa outside that assemblage.

For example, Ophthalmotilapia was grouped with Cyathopharynx, Cunningtonia,
Asprotilapia, Petrochromis and the Malawian genus Petrotilapia (then considered a species
of Petrochromis); furthermore, Regan suggested that Ophthalmotilapia was closely related to
Limnotilapia (now synonymised with Simochromis, see Greenwood, 1979) and that it had
'. . . given rise to Cyathopharynx'.

Petrochromis and Petrotilapia were included in this grouping because, in their dental
morphology and pattern, they are strikingly similar to Cunningtonia (see p. 280 below).

No reasons were given for including Asprotilapia, a taxon quite unlike the others in its
gross morphology and in its dentition; presumably the reason lay in Regan's (1920 : 42)
belief that the 'Skeleton (is) essentially similar to that of Ophthalmotilapia ventralis . . .'. The
skeletal features noted by Regan (1920 : 41 & 42) were, it should be emphasised, not those
used in this paper; most can be treated as plesiomorph characters when used at the level of
analysis involved here.

Presumably it was the same suite of skeletal characters which led Regan to suggest a close
relationship between Limnotilapia (i.e. Simochromis) and Ophthalmotilapia, a relationship
which I cannot accept since ''Limnotilapia'' apparently shares no derived features with any
members of the OA..

Ectodus (as a putative ancestral morphotype) was grouped by Regan (1920: 53) with
Callochromis, Xenotilapia and Grammatotria,\hQ taxa being given that order of increasing
morphological derivation. Again no detailed reasons are given for this grouping, save that
all its taxa have a 'Haplochromis'' type pharyngeal apophysis and small conical teeth. In
effect, however, it approximates closely to the arrangement proposed in this paper.

Regan (1920 : 53) also included, albeit implicitly rather than explicitly, Aulonocranus and
Trematocara with those genera listed in the previous paragraph. The association of
Aulonocranus with Trematocara was, presumably, based on both genera having hyper-
trophied cephalic laterosensory canal systems (Regan, 1920:47); no other relationship
with Aulonocranus was suggested, save that it is 'Intermediate between Haplochromis and
Trematocara.'' The linking of Aulonocranus and Trematocara with the Ectodus-
Grammatotria group (see above) was apparently based on the common possession of small
conical teeth and a 'Haplochromis' type of pharyngeal apophysis.

276 P. H. GREENWOOD

That Regan did not consider there to be any relationship between his Asprotilapia-
Ophthalmotilapia and his Ectodus-Grammatotria ( + Aulonocranus) groups is doubtless due
to his basic assumption that the endemic genera of Lake Tanganyika were derived from
'. . .two ancestral types, one nearly related to Limnotilapia and the other to Haplochromis'
(Regan, 1920:53).

After Regan's initial analysis of the Tanganyika cichlids, no further attempt to interrelate
the endemic genera of the lake was made for more than fifty years. In 1972 Fryer & lies paid
considerable attention to this problem, in particular to the assumption that there was a basic
diphyletic origin of the flock. However, despite their professed uncertainty about the value of
the pharyngeal apophysis as an indicator of phyletic relationships, Fryer & lies (1972 : 506,
fig. 337) virtually followed Regan's (1920) scheme. They were, of course, able to include
three genera described since that time, namely Lestradea, Cardiopharynx and Ophthalmo-
chromis. Cardiopharynx is now considered a synonym of Cyathopharynx (see p. 282)
and Ophthalmochromis was synonymised with Ophthalmotilapia by Liem (1981: 210-21 1).

As would be expected, Fryer & lies considered Ophthalmochromis and Cardiopharynx to
be the sister taxa of Ophthalmotilapia and Cardiopharynx respectively. Interestingly, they
associated Lestradea with Asprotilapia, Cunningtonia and the Ophthalmotilapia-
Ophthalmochromis pair, but gave no reasons for doing so. Their tentative alliance of
Cyathopharynx -{-Cardiopharynx with Lobochilotes and Limnotilapia is not explained
either, and only partly follows Regan who implied some relationship between Limnotilapia
and Lobochilotes, but also included Gephyrochromis, Simochromis and Tropheus in the
same group -again without a detailed explanation (Regan 1920:52). I can find no
synapomorphic characters to support the idea of a close relationship between Lobochilotes
and any member of the Ophthalmotilapia assemblage.

Like Regan, Fryer & lies (1972 : fig. 337) treat Aulonocranus and Trematocara as close
relatives, but give the two genera an origin separate from that of the taxa currently grouped
in the 0A.

Leptochromis (now renamed Reganochromis, see Whitley, 1928), a genus not mentioned
in Regan's analysis, is included by Fryer & lies as a member of their Ectodus, Callochromis,
Xenotilapia lineage, but again no reasons are given. This suggested relationship is discussed
on p. 278 below.

In effect, the main difference between the schemes proposed by Regan (1920) and Fryer &
lies (1972) lies in the latter authors not portraying any taxa in an ancestor-descendent
relationship, as was implied, or stated explicitly, in Regan's treatment. Also, Fryer & lies
indicate a more distant relationship than did Regan between Limnotilapia (i.e.
Simochromis) and other members of the latter author's Ophthalmotilapia group (see above,
p. 275).

In their final analysis Fryer & lies are less definite in their suggested relationships than was
Regan (see figure 337 in Fryer & lies, 1972 : 507); their phylogram was to be '. . . regarded as
extremely tentative'.

Liem's (1981) wide ranging review of the 0A is, in its treatment of anatomical and
morphological detail, far more thorough than either of the other two reviews. It was also the
first to employ a basically cladistic (sensu Hennig, 1966, phylogenetic sensu Wiley, 1981)
methodology.

Liem brought together certain taxa from Regan's two major groups (see above p. 275),
namely Ectodus with some elements of Regan's Ophthalmotilapia- Asprotilapia group, but
excluded other taxa from his Ectodus-Grammatotria assemblage (see p. 275 above).

The present analysis (also cladistically based) finally brings together, in a single lineage, all
but one pair of taxa from Regan's two groups, the exceptions being Petrochromis and the
Malawian genus Petrotilapia (see above, p. 275). It also includes Aulonocranus (but not
Trematocara) from a third group which Regan implied had some relationship with his
Callochromis-Grammatotria lineage (Regan, 1920 : 53). Effectively it hypothesizes that the
two major Regan groups are sister lineages within a larger taxon which, following Liem
(1981), can be named, informally, the Ophthalmotilapia assemblage (see Fig. 1 4).

Asprotilapia SA

..Ophthalmotilapia SA.

1-5

Fig. 14 Cladogram for the Ophthalmotilapia assemblage based on the 10 apomorphic characters
discussed in this paper. Page numbers, given in brackets after each numbered character, refer to
those pages on which the character is discussed in detail.
An interrogation mark precedes character 9 since its apomorphic status is doubtful (see p.

272).

( 1 ) Palatopterygoid gap (p. 254)

(2) Auricular process on the operculum
(P. 259)

(3) Morphological features of the palatine
bone (p. 257)

(4) Outline shape of the lachrymal (1st infra-
orbital bone), and the presence of six
laterosensory canal pores (p. 259)

(5) Adductor fossa on the lateral aspect of the
anguloarticularbone (p. 261)

(6) Intestine long and transversely coiled
p. 264)

(7) Presence of a pharyngeal hanging pad and
associated modifications to the gill-raker
morphology (p. 265)

(8) Dentary with a distinct 'step' (p. 267)

(9) First branched pelvic fin ray produced
(P. 272)

(10) Dorsal part of the flange behind the vertical
part of the preopercular laterosensory
canal not narrowing abruptly (p. 273)

278 P. H. GREENWOOD

Summary of the taxonomic conclusions and a discussion of the sister-group problem

in these and other lake cichlids

The Ophthalmotilapia assemblage, originally comprising the genera Ectodus, Lestradea,
Asprotilapia, Cunningtonia and Ophthalmotilapia (Liem, 1981) can now be expanded to
include Xenotilapia, Callochromis, Grammatotria, Aulonocranus and Cyathopharynx (with
which is synonymized Cardiopharynx).

Taxonomically, the assemblage is recognized as a monophyletic lineage on the grounds of
its member species sharing a unique congruence of five apomorphic characters (pages
254-262; Fig. 14).

Two major sublineages can be recognized within the assemblage.

One, characterized by having a short and simple coiled intestine, comprises the genera
Ectodus, Aulonocranus, Asprotilapia, Xenochromis, Callochromis and Grammatotria. It can
be further subdivided on the basis of various synapomorphies shared by four of its members
(see pages 263-274 and Fig. 14).

The other major sublineage contains Lestradea, Ophthalmotilapia, Cunningtonia and
Cyathopharynx, species in which the intestine is long and complexly coiled (see pages
264-265). Attempts to subdivide this lineage have not proved satisfactory, but it would seem
that Lestradea is the plesiomorph sister-group of the other three genera (pages 271-274 and
Fig. 14); possibly amongst these three genera Ophthalmotilapia and Cunningtonia are sister
taxa, but the entire group is, for the moment, probably best treated as an unresolved
polychotomy.

No sister-group, or even a single taxon, has so far been satisfactorily identified amongst the
cichlids of Lake Tanganyika. Regan's (1920 : 52) suggestion of close relationship between
Limnotilapia (i.e. Simochromis, see Greenwood, 1979) and Ophthalmotilapia (and hence
Cyathopharynx, Asprotilapia and Cunningtonia as well) cannot be corroborated on the basis
of shared synapomorphies.

When comparisons are made with other Tanganyika taxa the results are equally
unproductive except that two OA group synapomorphies occur, singly, in some species of
' Limnochromis* and Trematocara.

For example, in Trematocara marginata, but in no other species, there is a poorly
differentiated OA-like projection from the anteroventral angle of the lachrymal (see p. 259).
A similar projection occurs in 'Limnochromis'' permaxillaris and 'L.' pfefferi, both of which
are now placed in Poll's genus Gnathochromis. Both the ' 'Limnochromis* species and
Trematocara marginata have only 5 pores in the lachrymal, but other 'Limnochromis'
species which lack the projection, V otostigma, L. auritus and L. abeeli, have 5 or 6 pores.

Neither Trematocara nor ' ' Limnochromis'' has the characteristically shaped lachrymal of
the OA species, and the distribution pattern of the two OA group-features indicates an
independent (i.e. homoplastic) origin in the two genera.

Regan's (1920:53) suggested relationship between Aulonocranus and Trematocara
apparently stems from the hypertrophied laterosensory canals, and pores, present in both
taxa. Apart from that feature, and the weak OA-type lachrymal peak in one species of
Trematocara, there are no derived features uniquely shared by the two genera. Admittedly
there is a trend amongst the OA species for there to be some degree of hypertrophy in the
laterosensory canal system of the lachrymal. But, in the absence of other synapomorphies it
would be unrealistic to use a trend character as a basis for suggesting group relationships,
especially when that trend occurs in several other lineages as well. In this particular instance,
too, the lowest degree of canal enlargement is found in those OA species with the least
number of derived features (i.e. Ectodus and Lestradea), and which are therefore taken to be
the plesiomorph members of their respective subassemblages.

The tentative phylogenetic schemes proposed by Fryer & lies (1972 : 507, fig. 337) are not
always arranged so as to suggest sister-group relationships with taxa outside the OA. They
do, however, show Leptochromis (i.e. Reganochromis) as a sister taxon of Ectodus,
Callochromis, Xenotilapia and Grammatotria, and Aulonocranus is paired with

THE OPHTHALMOT1LAPIA ASSEMBLAGE OF CICHLID FISHES

279

Trematocara. Once again, there are no shared derived features to substantiate such relation-
ships, and none which might indicate that either Reganochromis or Trematocara is the
sister-group, or part of the sister-group, to the Ophthalmotilapia assemblage.

The only taxon which consistently shows more than a single OA group synapomorphy
amongst a number of its species is the Malawian genus Lethrinops.

I have examined alizarin preparations and dry skeletons of five Lethrinops species, the
type species Lethrinops lethrinus, and L. praeorbitalis, L. parvidens, L. auritus and L.
longimanus. In all there is a distinct palatopterygoid gap and a well-defined, although not
extensive OA type adductor fossa on the anguloarticular bone (Figs 1 5 & 16).

The palatopterygoid gap is relatively smaller than in most OA species, but in none of the
Lethrinops species examined is there any contact between the palatine and the
entopterygoid. Unlike members of the OA, the Lethrinops species have a much deeper
entopterygoid, and one that either rests along the upper margin of the quadrate or slightly
overlaps that bone medially. In OA species, most of the entopterygoid lies medial to the
quadrate, and is thus largely obscured by it in lateral view. As a consequence of this spatial
relationship the dorsal margin of the entopterygoid in Lethrinops lies at a level nearer the
palatine head than it does in OA species.

* mm

Fig. 15 Left suspensorium of Lethrinops lethrinus.

The shape of the palatine (Fig. 15) in Lethrinops differs somewhat from that in the OA
taxa(see p. 257 above). Its posterior margin is slightly concave, and the angle between this
margin and the head of the bone is less nearly rectangular; the posterodorsal margin
contributing to the angle is also less acute in Lethrinops; indeed, in some specimens and
species it is almost rounded. But, as in the OA species the body of the bone is expanded
posteriorly so that the bone's proportions are nearer those of the OA type than that
commonly found amongst African cichlids.

The occurrence of this particular palatine shape in association with a palatopterygoid gap
raises the question of whether or not the two characters are correlated. That a similarly
shaped palatine does occur in at least two species without a palatopterygoid gap (viz.
Limnochromis abeeli [Lake Tanganyika] and Astatotilapia macropsoides [Lakes Edward
and George]), would seem to argue against correlation, but the possibility requires further
testing.

The adductor fossa in Lethrinops (Fig. 16) is well defined but, as compared with the fossa
in members of the Asprotilapia subassemblage amongst the OA (p. 261) it is less extensive. It
is, however, comparable with the fossa in members of the Ophthalmotilapia subassemblage
(p. 265).

280 P. H. GREENWOOD

omm
Fig. 16 Left dentary and anguloarticular ofLethrinops lethrinus, lateral view.

An adductor fossa of this type is not restricted to members of the OA, but also occurs in
several seemingly unrelated taxa, including some 'Haplochromis* species from Malawi (see
p. 261). Thus, in itself, the fossa cannot be considered a unique apomorphy; its value as a
group synapomorphy stems solely from its congruence with other apomorphic characters.

There is a third derived character found in the five Lethrinops species which is also present
in one subgroup of the OA, namely a stepped dorsal margin to the dentary, with the teeth
confined to the higher level of the step (Fig. 16). Amongst the OA taxa this feature is found
only in Xenotilapia, Callochromis and Grammatotria (all members of the Asprotilapia
subassemblage; see p. 267). Its restricted distribution within the OA considerably reduces its
potential significance as a character indicative of a possible relationship between Lethrinops
and the OA. That it apparently occurs only in these OA species and in Lethrinops, and that
both groups have a palatopterygoid gap is, nevertheless, intriguing and requires further
investigation.

Attempts to evaluate the two apomorphic features shared by Lethrinops and the OA in its
entirety (i.e. the palatopterygoid gap and the adductor fossa) are hampered by lack of
comparative data from the Malawi cichlids as a whole. A relatively superficial survey shows,
however, that the adductor fossa is present only in some haplochromine species (see p. 26 1 ).
Whether or not these haplochromines are closely related to Lethrinops has not been
adequately tested, but preliminary investigations do not suggest that this is the case.

The situation regarding the palatopterygoid gap is different. I have examined specimens of
all the described genera of Malawi fishes, but by no means all their included species. In none
is there a palatopterygoid gap. Thus, the character appears restricted to Lethrinops and the
OA (see also p. 255).

In summary, it seems that no group of Lake Tanganyika cichlids consistently shows one or
more of the group synapomorphies for the OA. On the other hand, in Lake Malawi at least
some species of Lethrinops share two derived features with all members of the OA, and
only one of these features (the adductor fossa) occurs in other Malawi taxa. The Lethrinops
species also have a third derived feature, the shape of the dentary, which is present in one
lineage amongst the OA.

As it stands, this indication of a possible sister-group relationship between the OA and
Lethrinops is no more than suggestive. It could well be refuted as an example of convergence
when more is known about the interrelationships of the cichlids from Lake Malawi and those
of Lake Tanganyika.

There are several cases of close similarity existing between certain features in endemic taxa
of each lake, but few between species in those lakes and endemic taxa from Lake Victoria.

As examples one may mention that the dentition in Cunningtonia is virtually identical
with that in Petrotilapia and there are marked similarities in the jaw anatomy of the two
genera (Petrochromis from Lake Tanganyika can also be included in this example); or, the
morphology of the dentary in Asprotilapia which is like that of Labeotropheus a Malawian
genus also sharing several features with Tropheus from Lake Tanganyika. Finally, one can
cite the many similarities in syncranial architecture existing between Simochromis of
Tanganyika and the Pseudotropheus species complex of Lake Malawi.

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES

281

These are by no means the only cases that can be, or have been, cited of supposed
convergence or parallelism between the cichlid faunas of the two lakes (see Fryer & lies,
1 972). Adequate explanations for these similarities are, however, far more difficult to find.

An example of similarity involving much greater geographical separation than that
between Tanganyika and Malawi, and one which incorporates a greater number of species
as well as a mosaic distribution of similar characters amongst the species, involves two
members of the OA, another, unrelated, genus from Lake Tanganyika, a Malawian taxon
and Neopharynx schwetzi, a monotypic genus from the lower Fwa (Kasai drainage in south-
western Zaire; for a full description of N. schwetzi, see Poll, 1948).

>mm

Fig. 17 Lower pharyngeal bone of Neopharynx schwetzi, occlusal view (from a specimen in

paratypical series, MRAC 7 1 29 1-7 1 299).

Neopharynx schwetzi has a lower pharyngeal bone morphologically and dentally almost
identical with that of Cyathopharynx (see Figs 17 & 24). Its oral dentition, in contrast, is
virtually identical with that in Petrochromis (Tanganyika) and Petrotilapia (Malawi), and is
quite unlike that in Cyathopharynx. As far as the morphology of the teeth is concerned, but
not their distribution on the dentary, Neopharynx also closely resembles Cunningtonia of
Lake Tanganyika. It differs from all three taxa in the shape of its premaxilla, but the
morphology of the premaxillary teeth is, as might be expected, very similar in all four genera.

The relationships of Neopharynx have yet to be established; probably they lie with two
other Fwa endemics, Cyclopharynx and Callopharynx, genera having an extreme
development of the Neopharynx-Cyathopharynx type of lower pharyngeal bone (for details
see Poll, 1948).

Neopharynx has neither an OA type lachrymal, a palatopterygoid gap, nor an OA-type of
adductor fossa, and the shape of its palatine bone is close to the generalized form. Thus the
similarities between Neopharynx, Cyathopharynx and Cunningtonia are undoubtedly
homoplastic, as most probably are the similarities shared with Petrochromis and
Petrotilapia.

The Neopharynx example underlines the problems involved in attempting to work out
interrelationships amongst cichlid fishes, as do the repeated appearances of certain derived
features shown by members of the Ophthalmotilapia assemblage in species which appear to
be but distantly related to the OA.

Surmises about the interrelationships of African lake cichlids have, I believe, been unduly
influenced, perhaps even inhibited, by three major factors. Firstly, the idea that there are two

282 P. H. GREENWOOD

basic lineages, a ' Tilapia" line and a 'Haplochromis' one (see discussion in Greenwood, 1 978;
also p. 274 above). Secondly, that the major lakes are, faunistically, closed basins and have
been so almost since their inception, with the result that the cichlids of a lake are presumed
to have evolved from one or a few ancestral species originally trapped there (see discussion in
Fryer & lies, 1972; and Greenwood, 1974). In other words, assumed histories for the lakes
have been given too great a weight in deciding whether a feature was the result of
convergence, parallelism, or the consequence of common ancestry.

The third, and overriding, factor is a paucity of specific and critical studies on the
phylogeny of the fishes. Overall resemblances, or the use of characters without adequate
outgroup comparisons, are often major weaknesses influencing decisions on relationships.

The effect of these three factors has resulted in a tendency to restrict the search for sister-
groups to a single lake and to the appropriate 'Tilapia' or 'Haplochromis' lineage.
Admittedly, at lower levels of universality sister species are generally to be found within the
same lake or proto-lake system (Greenwood, 1980); the problems arise when attempting to
establish relationships at somewhat higher taxonomic levels. The Ophthalmotilapia
assemblage, and the search for its sister-group are good examples of problems encountered at
these two levels.

The existence of endemic species flocks, the superficially close similarity of species in
different flocks, and indeed of many different taxa outside the lakes, all help to complicate
the issue. Under such circumstances the possibility and probability of homoplasy are
theoretically enhanced, as in practice are the problems associated with their resolution.

What is needed to resolve these problems are tests of the assumption that a so-called
species flock is really of monophyletic origin. If a lake's cichlid fauna was derived from a few
species which are not true sister species, and if the true sister taxa were the ancestors of
another flock, then the situation suggested by the apparent relationship of Lethrinops
(Malawi) and the 0A (Tanganyika) could well be a real one. The idea first put forward by
Regan (1922) that the Malawi 'flock' carries indicators of its monophyly must be seriously
questioned (Greenwood, in press). No indicators of monophyly have been suggested for
the Tanganyika 'flock' (even at the levels of the supposed 'Tilapia' and "Haplochromis" type
basic stocks). The possibility of a close relationship between the faunas of the two lakes
deserves very careful examination.

The status of Cyathopharynx Regan, 1920 and Cardiopharynx Poll, 1942

In his original description of the monotypic genus Cardiopharynx, Poll (1942 : 346) noted
the great similarity between its peculiarly shaped lower pharyngeal bone and the lower
pharyngeal of Cyathopharynx. He differentiated the two genera because Cardiopharynx has,
as compared with Cyathopharynx:

(i) Larger scales (36-38 c/48-64 in a longitudinal series (see Poll, 1956:1 27).

(ii) Jaw teeth in two rows, the teeth, in both jaws, of equal size (c/3-5 rows; teeth in the

outer row larger than those of the inner rows),
(iii) Dentigerous surface of the lower pharyngeal bone cardiform (cf rounded in

Cyathopharynx)
(iv) Supraoccipital extending forward to a level above the anterior margin of the orbit

(c/to the mid-orbital region only)
(v) Parietal crests ending above the centre of the orbit (c/extending to a point above the

posterior part of the orbit)
(vi) More vertebrae (36, i.e. 17+19) c/32-34 (i.e. 1 6 or 1 7 + 1 6 or 1 7)

Poll gives no reasons why these characters should be used to separate the taxa at a generic
level, and neither does he indicate why the great similarity in pharyngeal morphology, and
its uniqueness, should be outweighed as an indicator of close phyletic relationship by the
diagnostic characters he enumerates.

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES 283

None of these latter features can be considered uniquely apomorphic for Cardiopharynx,
and now that more material is available several are found to be less trenchant than was first
thought to be the case, as the following comments show.

The teeth in both jaws of all Cardiopharynx specimens I examined are invariably arranged
in two rows, but in Cyathopharynx there is a greater variation than was intimated by Poll
(1942 & 1956). In the majority of specimens examined, the inner premaxillary row is, in
places, irregularly arranged so as to give the appearance of a double row wherever the
irregularities occur. Occasionally there are specimens in which the inner tooth row is clearly
and regularly double, thus giving a total count of three tooth rows; also occasionally it is
distinctly single, giving a total of two rows. In none of the specimens is there a total of more
than three premaxillary rows. The inner row of teeth in the dentary is generally single; in a
few fishes, however, it is somewhat irregular and so comes to resemble the modal condition
in the premaxilla.

Contrary to Poll (1946), I can find no marked difference between the taxa in the relative
size of inner and outer teeth. In both genera the outer teeth, in both jaws, are clearly taller
and stouter than those of the inner row or rows, and not of equal size in Cardiopharynx as
claimed by Poll. The most that can be said is that in Cardiopharynx the size difference
between outer and inner row teeth is a little less marked than in Cyathopharynx.

In a later redescription of both taxa, Poll (1956) commented on the outer teeth of
Cardiopharynx being more or less tricuspid in young fishes, but he gave no size-range over
which tricuspid teeth are found. In specimens 60-105 mm SL I have examined, there are no
outer tricuspids, whereas in specimens of Cyathopharynx of a comparable size range and up
to 1 12 mm SL, distinctly, and also weakly, tricuspid teeth do occur. In larger Cyathopharynx
specimens the teeth are exclusively and clearly unicuspid.

The difference in the shape of the dentigerous surface of the lower pharyngeal bone (iii
above, p. 282) is due entirely to a marked median depression in the posterior face of the bone
and of the toothed area in Cardiopharynx. In Cyathopharynx this margin of the bone is
slightly and more broadly indented, and there is no indentation of the posterior tooth row
(Fig. 23).

In all other respects the lower pharyngeal bone in both taxa is identical. As noted above (p.
27 1 ) it represents a uniquely derived condition amongst the cichlids of Lake Tanganyika.

The shape of the pharyngeal teeth, tall and slender, with spatulate crowns that are not
broader than the neck, and their cardiform pattern on the alveolar surface of the bone, is the
same in both genera (Fig. 24). Likewise, the morphology of the principal upper pharyngeal
bones is identical, as is the morphology and pattern of their teeth. Unlike the lower teeth,
those on the upper pharyngeal bones do have a slight, shoulder-like cusp at the base of the
spatulate crown surface.

The anterior point reached by the supraoccipital and parietal crests (iv & v above) is
variable intragenerically. In the skulls I have examined there are specimens from each genus
showing conditions intermediate between those originally used as diagnostic features for the
two genera.

Finally, there are the supposedly intergeneric differences in vertebral number (vi above). I
have examined 15 specimens of Cardiopharynx schoutedeni (13 from radiographs, 2 as
alizarin preparations), and 12 of Cyathopharynx furcifer (10 from radiographs and 2 dry
skeletons), and obtained the following counts:

Cardiopharynx: Total number (excluding the fused Ui-PUi centra) 33 (f5) and 34
(flO), comprising 1 5 (fl), 16 (f7) or 17 (f7) abdominal and 16 (fl), 17(f9) or 18 (f5) caudal
elements.

Cyathopharynx: Total number (excluding the fused Ui-PUi centra) 32 (f5) 33 (f6) or 34
(fl ), comprising 1 6 (f9) or 1 7 (D) abdominal and 1 6 (f7) or 1 7 (f5) caudal elements.

The differences in range are not very marked and there is a complete overlap in other
counts, but with a slight difference in the modal number for total [34 c/33] and abdominal
counts [1 7 cf\ 6] for Cardiopharynx and Cyathopharynx respectively.

Thus, of Poll's (1942) original diagnostic features, only the difference in scale size remains.

284 P. H. GREENWOOD

There are, however, other differences which were noted in the original diagnosis.
Cyathopharynx has proportionately longer pelvic fins, in males the tip of this fin reaches the
last anal fin ray or even to as far as the caudal fin fork; in Cardiopharynx it reaches only to
about the middle of the anal fin. Also, in Cyathopharynx the first pelvic ray is clearly the
longest whereas in Cardiopharynx either the first and second rays are equally protracted or
the second ray may be the longest.

Other differences involve neurocranial shape (Figs 18 & 19). Cardiopharynx has a
shallower skull than does Cyathopharynx, the prootic portion of its otic bulla is more
inflated, and the interorbital region is much narrower.

Undoubtedly the two taxa are distinguishable. The problem is to decide at what
taxonomic level their separation should be recognized.

To recognize two genera on the basis of the differences discussed above is to obscure the
fact that, amongst the Lake Tanganyika cichlids, Cyathopharynx and Cardiopharynx share a
unique apomorphy (the form of the lower pharyngeal bone) which would indicate a common
ancestry not shared with any other taxon. That relationship is, I believe, best indicated by
treating the two species as members of a single genus, Cyathopharynx Regan, 1920.

Cyathopharynx Regan, 1 920

Cyathopharynx Regan, 1920. Ann. Mag. nat. Hist. (9), 5: 42-43.
Cardiopharynx Poll, 1942. Revue Zool. Bot. afr., 36: 346-347.

TYPE SPECIES. Tilapia grandoculis Boulenger, 1899. Trans, zool. Soc. Lond. 15: 94, pi. XIX,
fig. 6.

Poll (1946 : 283^) has synonymized this species with C.furcifer (Blgr), 1 898.

DIAGNOSIS. A member of the Ophthalmotilapia assemblage, distinguished from other
members of that group by having a cardiform dentigerous surface to the lower pharyngeal
bone, the body of which is inflated and nearly cardiform in outline.

Cyathopharynx is distinguished from other species with a cardiform alveolar surface to the
lower pharyngeal bone by, among other features, its <9A group characters (see p. 262) and by
the marked elongation of the first, or first and second pelvic fin rays in adult male fishes;
these protracted rays extend to at least the middle of the anal fin, and in one species, some-
times as far as the fork of the caudal fin.

Description

Neurocranium (Figs 1 8 & 1 9). In its general outline, the skull differs little from that of the
generalized haplochromine type in which the preorbital profile is slightly decurved. The
orbit, however, is relatively larger than in a generalized skull, and the otico-occipital region
is shorter, a correlate, probably, of the enlarged orbit since the ethmoid region retains the
same proportions as in a generalized skull.

The ventral apophysis for the upper pharyngeal bones is of a weak 'Tropheus1 type, in
which the basioccipital barely contributes to the articular surface (see Greenwood, 1978; also
p. 274 above).

Suspensorium (Figs 1 C & D). As in other members of the Ophthalmotilapia assemblage,
there is a distinct palatopterygoid gap (see p. 255), and the entopterygoid is shallow, with
only one-third to one-quarter of its depth visible above the quadrate margin. The
hyomadibula has a narrow flange anterior and dorsal to the symplectic process. The shape
and proportions of the symplectic are typically those of an OA species (see p. 256).

Infraorbital series (Figs 3 A & F). The lachrymal bone (1st infraorbital) has the typical
outline shape, and the anteroventral process, of an OA taxon (see p. 259). There are six
pores opening from the laterosensory canal system, the tubular part of which is somewhat

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES

285

5mm

Fig. 18 Neurocranium of Cyathopharynx furcifer in : A, left lateral view; B, dorsal view.

inflated. The pores, however, do not show a corresponding enlargement (i.e. they do not
deviate noticeably from the generalized condition). The other infraorbital bones are little
more than tubular ossifications around the sensory canal, but do have low dorsal and ventral
keels.

Myology. Division I of the adductor mandibulae complex has an extensive origin along
the vertical limb of the preoperculum, but division II has its preopercular origin mainly from
the horizontal limb of that bone; only a small area extends onto the vertical limb.

The dorsal gill-arch muscles compare closely, in most respects, with those of other 0A
species (see Liem, 1981 : 196-7 & 205, & fig. 8; also p. 258 above). The retractor dorsalis
muscles are especially well developed with, in some individuals of both species, indications
of a subdivison into dorsal and ventral components.

Dentition (Fig. 20). Some aspects of the oral dentition have been commented upon already
(p. 283 above). The outer row teeth in both jaws are tall and slender. In C. furcifer the crown
is slightly broader than the neck and shaft of the tooth, whereas in C. schoutedeni the crown
is no wider than the shaft. The crowns are slightly recurved in both species.

Premaxillary outer row teeth are aligned vertically to the alveolar surface, but in the
dentary the teeth situated anteriorly and anterolaterally are procumbent. The posterior
dentary teeth are vertical, those of C. furcifer continuing for some distance up the coronoid
process.

Inner row teeth in both jaws, and both species, are noticeably smaller than those of the
outer row, and are implanted so as to lie almost horizontally.

Mouth. The lips are thin, and the gape is horizontal.

286

P. H. GREENWOOD

5mm

Fig. 19 Neurocranium of Cyathopharynx schoutedeni in : A, left lateral view; B, dorsal view.

Fig. 20 Outer row jaw teeth (drawn in situ) from : A & B, Cyathopharynx schoutedeni, specimen
103 mm SL (premaxillae and dentary respectively); C & D, C. furcifer, specimen 1 13 mm SL
(premaxilla and dentary, respectively). Dentary teeth viewed from below.

Jaws. The dentary in both species is a moderately slender bone, shallower and less robust in
C. schoutedeni than in C. furcifer (Fig. 2 1 ). Anteriorly and anterolaterally the dorsal aspect of
the bone is expanded into a broad surface which extends outwards to overhang, as a narrow
shelf, the body of the bone. The tooth rows occupy only the outermost part of the surface,
with the result that there is a wide expanse of bone lying medial to them. The laterosensory
canal system and its openings in C. furcifer are more cavernous than those in C. schoutedeni.
The anguloarticular has a well-defined but short fossa for the adductor mandibulae
muscle, with the ridge delimiting its anterior margin particularly deep and prominent.
The premaxilla (Fig. 22) has no especially outstanding features.

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES

287

Fig. 21 Dentary and anguloarticular, in left lateral and occlusal views respectively, of : A & B,
Cyathopharynxfurcifen C & D, C. schoutedeni.

5mm

Fig. 22 A & B, premaxilla ofCyathopharynxfurcifer, anterior and lateral view; C, maxilla (left)

seen from a slightly ventrolateral viewpoint.

288

P. H. GREENWOOD

As compared with the generalized type of maxilla, that in Cyathopharynx is foreshortened
and has a well-developed, long-based posterior process (see also p. 269).

The pharyngeal bones. The shape and other peculiar features of the lower pharyngeal bone
(Fig. 23) are described on page 283.

The upper pharyngeal bones differ less markedly from the usual condition seen in African
cichlids. The outline of the alveolar surface of the major element (pharyngobranchial 3) is
noticeably ovoid, but otherwise differs little from the generalised condition. Their principal
difference lies in the relatively greater alveolar surface area, and its more elongate
proportions. Other differences are found in the less prominent facets for articulation with the
3rd and 4th epibranchials, and in the lower summit facet (nomenclature following Barel et
al, 1976: 214, fig. 26).

The lower pharyngeal teeth (Fig. 24) are slender, near cylindrical in cross-section and are
closely packed. Those at the periphery of the dentigerous area are weakly curved, the others

i mm

Fig. 23 Lower pharyngeal bone, in occlusal view of: A, Cyathopharynx furcifer, B,
C. schoutedeni, and, in ventral view, C, of C. furcifer.

I \

0.25mm

Fig. 24 Cyathopharynx furcifer, pharyngeal teeth (lateral and semiocclusal views) from : A, the

posterior; and B, anterior dental fields.

THE OPHTHALMOTILAPIA ASSEMBLAGE OF CICHLID FISHES 289

erect. There is a noticeable and rapid increase in the height of the teeth forming the posterior
5 or 6 rows, with the teeth of the posterior row tallest and stoutest. The elongate crown of
each tooth is flat, and slopes gently upwards and backwards. There is no indication of a low
shoulder-like projection or cusp at the base of the crown.

The shape and dense arrangement of the upper pharyngeal teeth are very similar to those
of the lower bone, the teeth differing only in having a small shoulder or cusp at the base of the
posteriorly directed crown.

Vertebrae. Regan (1920 : 43), in his original description of Cyathopharynx, noted that the
third vertebra lacks an inferior apophysis, from which the retractor dorsalis muscles
originate. In four of the five dry skeletons and alizarin preparations I examined, a low
apophysis is present on the fourth centrum in one fish and on the fifth centrum in three
others, but none is present in the fifth specimen.
Vertebral counts for the two species are given on page 283.

Squamation. Scales on the body are weakly ctenoid except for the cycloid scales on the chest
and belly. Those covering the thoracic region are small, and are fairly abruptly demarcated
from the larger scales on the ventral flanks and the belly.

The two Cyathopharynx species differ, disjunctly, in the size of their body scales, with
C. schoutedeni having 36-38 scales in a longitudinal series, and C. furcifer 48-64. The
species also differ, slightly, in the posterior extension of the upper lateral line pore scales,
those in C. furcifer usually extending almost to the caudal fin base, whereas in C. schoutedeni
the pore scales terminate at a level 3 or 4 scale rows anterior to the caudal base. There is,
however, some interspecific overlap in this feature.

Fins. Little can be added to the description (p. 272) of the protracted first or first and second
pelvic fin rays in adult males. In females and juvenile males these rays are also noticeably
longer than the others, but usually do not extend beyond the level of the anus; exceptionally
they may reach the spinous part of that fin.

The caudal fin is forked; adult males have the two upper- and lowermost principal
branched rays produced into fine filaments. Rows of small, barely overlapping scales are
present on the fin membrane (except between the three middle rays), and extend to the level
of the fork.

Gut. The intestine is long (ca 3 to 4 times SL) and complexly coiled in a predominantly
transverse direction (see p. 264).

Contained species

Cyathopharynx furcifer (Blgr) 1898
Cyathopharynx schoutedeni (Poll) 1 942

Both are lacustrine species endemic to Lake Tanganyika; for detailed descriptions, figures
and biological data see Poll (1956: 1 30-1 37 & 1 25-1 30 for the species respectively).

Acknowledgements

Gordon Howes has once again devoted much time and patience to producing the figures, and
for that I am especially grateful. I also owe him a great deal of gratitude for his help with all
the numerous, and monotonous, tasks he has undertaken in helping with the production of
this paper.

I am greatly indebted to Dr Thys van den Audenaerde of the Koninklijk Museum voor
Midden-Afrika, Tervuren, who so graciously allowed me to borrow the types and other
material of the river Fwa cichlids.

Finally, it is a great pleasure to thank my colleague Professor Karel Liem of the MCZ
whose original paper on the <9A has proved both a stimulus and a focal point for my studies
on the interrelationships of the cichlid species flocks from the African lakes.

290 P. H. GREENWOOD

References

Barel, C. D. N., Witte, F. & van Oijen, M. J. P. 1976. The shape of the skeletal elements in the head of

a generalized Haplochromis species: H. elegans Trewavas 1933 (Pisces, Cichlidae). Neth. J. Zool. 26

(2): 163-265.
Boulenger, G. A. 1898. Report on the collection of fishes made by Mr J. E. S. Moore in Lake

Tanganyika during his expedition, 1895-96. Trans, zool. Soc. Lond. 15 (1) : 1-30.
Brichard, P. 1978. Fishes of Lake Tanganyika. T.F.H. Publications Inc., New Jersey & London.
Fryer, G. & lies, T. D, 1972. The cichlid fishes of the Great Lakes of Africa. Their biology and

evolution. Oliver & Boyd. Edinburgh.
Greenwood, P. H. 1965. Environmental effects on the pharyngeal mill of a cichlid fish,

Astatoreochromis alluaudi and their taxonomic implications. Proc. Linn. Soc. Lond. 176: 1-10.

1974. Cichlid fishes of Lake Victoria, East Africa: the biology and evolution of a species flock.

Bull. Br. Mus. nat. Hist. (Zool.) Suppl. 6: 1-134.

1978. A review of the pharyngeal apophysis and its significance in the classification of African

cichlid fishes. Bull. Br. Mus. nat. Hist. (Zool.) 33: 297-323.

1979. Towards a phyletic classification of the 'genus' Haplochromis (Pisces, Cichlidae) and

related taxa. Part I. Bull. Br. Mus. nat. Hist. (Zool.) 35 : 265-322.

1980. Towards a phyletic classification of the 'genus' Haplochromis (Pisces, Cichlidae) and

related taxa. Part II: the species from Lakes Victoria, Nabugabo, Edward, George and Kivu. Bull. Br.
Mus. nat. Hist. (Zool.) 39 : 1-101.

1981. The haplochromine fishes of the East African Lakes. Kraus-Thomson Organization

GmbH. Munich & London.
Hennig, W. 1966. Phylogenetic systematics. University of Illinois Press, Urbana.
Liem, K. F. 1973. Evolutionary strategies and morphological innovations: cichlid pharyngeal jaws.

Syst. Zool. 22 (4): 42 5-441.

1981. A phyletic study of the Lake Tanganyika cichlid genera Asprotilapia, Ectodus,

Lestradea, Cunningtonia, Ophthalmochromis, and Ophthalmotilapia. Bull. Mus. comp. Zool. Harv.
149(3): 191-214.

& Osse, J. W. M. 1975. Biological versatility, evolution and food resource exploitation in

African cichlid fishes. Am. Zool. 15 (2) : 427-454.

& Stewart, D. J. 1976. Evolution of the scale-eating cichlid fishes of Lake Tanganyika: a

generic revision with a description of a new species. Bull. Mus. comp. Zool. Harv. 147 (7) : 3 19-350.
Poll, M. 1942. Cichlidae nouveaux du Lac Tanganyika appartenant aux collections du Musee du
Congo. Revue Zool. Bot. afr. 36 (4) : 343-360.

1946. Revision de la faune ichthyologique du lac Tanganyika. Annls. Mus. Congo beige C.

Zool.Serl,4(l): 141-364.

1948. Descriptions de Cichlidae nouveaux recueillis par le Dr. J. Schwetz dans la riviere Fwa

(Congo beige). Revue Zool. Bot. afr. 41 : 91-104.

1956. Poissons Cichlidae. Result, sclent. Explor. hydrobiol. lac Tanganyika (1946-1947), 3

fasc.Sb: 1-619.

1981. Contribution a la faune ichthyologique du lac Tanganyika. Revision du genre

Limnochromis Regan 1920. Description de trois genres nouveaux et d'une espece nouvelle:

Cyprichromis brieni. Annals Soc. r. zool. Belg. Ill: 163-179.
Regan, C. T. 1920. The classification of the fishes of the family Cichlidae-I. The Tanganyika

genera. Ann. Mag. nat. Hist. (9) 5 : 33-53.

1922. The cichlid fishes of Lake Nyassa. Proc. zool. Soc. Lond. 1921 : 675-727.

Stiassny, M. L. J. 1981. Phylogenetic versus convergent relationship between piscivorous cichlid

fishes from Lakes Malawi and Tanganyika. Bull. Br. Mus. nat. Hist. (Zool.) 40 : 67-101.
Trewavas, E. 1973. On the cichlid fishes of the genus Pelmatochromis with a proposal of a new

genus for P. congicus; on the relationship between Pelmatochromis and Tilapia and the recognition

of Sarotherodon as a distinct genus. Bull. Br. Mus. nat. Hist. (Zool.) 25 : 1-26.
~^==-4574. The freshwater fishes of rivers Mungo and Meme and Lakes Kotto, Mboandong and

Soden, West Cameroon. Bull. Br. Mus. nat. Hist. (Zool.) 26 : 299^1 9.
Whitley, G. P. 1*928. Studies in ichthyology. No. 3. Rec. Aust. Mus. 17 : 101-143.
Wiley, E. O. \9jH?Phylogenetics. John Wiley & Sons. New York.

Manuscript accepted for publication 9 September 1982

East African Cichlid Fishes

The haplochromine fishes of the east African lakes
P. H. Greenwood, British Museum (Natural History)

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Osteology, genitalia and the relationships of
Acanthodactylus (Reptilia: Lacertidae)

• 2 6 h AY 198

E.N.Arnold t

Department of Zoology, British Museum (Natural History), Cromwell Road, London
SW7 5BD

Contents

Synopsis 291

Introduction 292

The reality of the genus Acanthodactylus 293

Systematic position of Eremias guineensis 296

Characters varying within Acanthodactylus 297

Osteological characters 297

Hemipenial characters 300

Polarity of hemipenial features 303

Origin of hemipenial differences 304

Description of the hemipenes of different species 305

External features 307

Species boundaries and species groups 311

A. micropholis 311

The A. cantons group, A. gongrorhynchatus and A. haasi. . . . 311

A. schreiberi and A. boskianus 315

The A. grandis complex 316

The A. tristrami group 318

The /I. erythrurus group 318

The A. pardalis group 319

The A. scutellatus group 322

The A. opheodurus group 329

Inter-relationship of the species of Acanthodactylus 329

Acknowledgements 336

References 336

Addendum 338

Synopsis

Acanthodactylus is reassessed, supplementing the external features previously used with new data from
the skeleton and hemipenis. The genus appears to be closely related to Eremias and Mesalina rather
than to Latastia as was previously thought, and 'Eremias' guineensis is confirmed as an
Acanthodactylus.

It is suggested that genitalia have an enhanced propensity to 'store' evidence of shared evolutionary
experience in the form of common characters among descendants, when compared with other organ
systems. Such characters deserve relatively high weight in assessing relationships. However, not all
genital characters can be interpreted in this way for some seem likely to have evolved as physical
isolating mechanisms between similar species and, in such cases, closely related forms may have
radically different genitalia. Differences of this kind, together with some osteological features, have
proved important in establishing the species status of several forms usually regarded as subspecies or
varieties. Thus the four subspecies of A. cantoris are now accorded full species status as A. cantoris, A.
blanfordii, A. schmidti and A. arabicus and a similar upgrading may well be appropriate for two taxa
usually subsumed in A. tristrami: A. (/.) tristrami and A. (t.) orientalis. Within the A. pardalis complex,
A. pardalis, A. maculatus and A. spinicauda are regarded as separate species and the form listed by

Bull. Br. Mm. nat. Hist. (Zool.) 44(5): 29 1-339

Issued 26 May 1983

292 E. N. ARNOLD

Boulenger (1921) as var. bedriagai is treated as a subspecies of A. pardalis; a similar un-named West
Moroccan population is also assigned to this species. Recently available material makes it probable
that A. grandis and A. fraseri are closely related and perhaps allocatable to the same highly variable
species. Within the A. scutellatus group the following taxa recognized by Bons and Girot (1962) are
assigned to A. scutellatus itself: A. s. scutellatus, A. s. audouini, A. s. hardyi, A. i. inornatus and A.
dumerilii. A. longipes is retained as a separate species and the same status is given to A. aureus which
Bons and Girot regarded as a subspecies of A. inornatus. Geographical variation requires considerable
further study in a number of taxa including the A. grandis complex, A. boskianus and the A. scutellatus
group but a number of currently recognized subspecies are invalid such as A. tristrami iracensis
Schmidt, 1939 ( = A. (/.) orientalis), A. pardalis latastii ( = A. maculatus) and probably several of the
forms in the A. scutellatus group.

An attempt has been made to estimate a phylogeny for the species of Acanthodactylus, although
considerable character conflict exists.

Introduction

The lacertid lizard genus Acanthodactylus Wiegmann, 1834 contains about 26 species. It
occurs from Spain and Portugal across the Sahara desert and its periphery to the Red Sea,
over most of Arabia and as far north as Cyprus and the Syrian-Turkish border; it also
extends through Iraq, south and east Iran, south Afghanistan, Pakistan and northwest India.
All its members are quite small, maximum body sizes of populations varying from about
52 mm to around 105 mm from snout to vent. They are diurnal and essentially ground-
dwelling lizards usually found in relatively flat, often sandy situations and occurring in a
wide variety of dry habitats which usually have at least some vegetation and range from open
woodland to the borders of quite severe desert. Substrates occupied vary from quite hard
loess and clay to aeolian sand. All species appear to be mainly active hunters and feed largely
on small invertebrates including ants. Body temperatures of normally active animals are
usually in the range 36° to 41° C (personal observations; Duvdevani & Borut, 1974a). Like
most open-country lizards, Acanthodactylus species are probably very prone to bird
predation and are also taken by other vertebrates such as snakes and monitor lizards
(Varanus). Predator avoidance seems to depend largely on crypsis (colour match with
substrate is often very good), fleeing, tail autotomy and the use of burrows. All species are
oviparous and usual clutch size varies from two to about seven eggs, females in many
populations appearing to produce more than one clutch annually. The majority of forms
seem to mature within a year of hatching although some, like A. erythrurus in Spain and
Portugal, may take two seasons.

The most detailed synopsis of the genus to date is that of Boulenger (192 1) which although
inevitably to some extent out dated, remains extremely useful, providing detailed descrip-
tions of many forms. However, the amount of material available for study has increased
massively over the past fifty years. In particular, specimens from many areas previously
unsampled, such as much of the Sahara desert and Arabia, have been obtained. Furthermore,
both Boulenger and subsequent workers have depended almost entirely on external
characters. As there are reasons for believing that these on their own can be misleading when
judging lacertid relationships (see for example Arnold, 1973) it seems worthwhile to increase
the range of characters considered and, in the present paper, osteology and the structure of
the hemipenis are taken into account.

What follows is not a formal revision but an overview of Acanthodactylus is given paying
especial attention to the objective reality of the genus, species boundaries and, so far as they
can be judged, inter-relationships of its members. Although the results presented here differ
considerably from previously held opinions, the genus still requires a more detailed appraisal
based on the large but scattered collections available in continental Europe and North
America.

RELATIONSHIPS OF ACANTHODACTYLUS 293

In this paper, the methods of phylogeny estimation employed are those discussed by
Arnold (1981 a). They depend largely but not entirely on Hennig's (1950, 1 966) precept that
joint possession of a derived character state is prima Jade evidence of relationship. The word
relationship is used in its genealogical sense: two species are more closely related to each
other than to a third if they share a common ancestor not shared by that form. The following
terms coined by Hennig are used, together with the adjectives derived from them:
apomorphy — a derived character state; synapomorphy — a derived character state shared by
two or more species and possibly indicating their relationship to each other; plesiomorphy —
a primitive character state; symplesiomorphy — a primitive character state snared by two or
more species, it does not indicate their relationship. Monophyletic and holophyletic are used
in the sense of Ashlock (1974).

Abbreviations used

BM(NH) — British Museum (Natural History), London; CAS — California Academy of
Sciences, San Francisco; CM— Carnegie Museum, Pittsburgh; EBD — Estacion Biologica de
Donana, Seville); INHM — Iraq Natural History Museum, Baghdad; JUM — Jordan
University Museum; MCZ — Museum of Comparative Zoology, Harvard; NMW —
Naturhistorisches Museum, Vienna; RSM — Royal Scottish Museum; USNM — United
States National Museum, Washington.

The reality of the genus Acanthodactylus

On the basis of external features, Boulenger (19 18a) described the genus Acanthodactylus as
'un des plus naturels et des plus nettement delimites de la famille des Lacertides'. Exam-
ination of skeletal and hemipenial characters provides additional support for Boulenger's
view and Acanthodactylus is confirmed as a clearly denned assemblage that shows no
integration into other genera. Most of its features are found in the lizard usually known as
Eremias guineensis but it is certain that this form should really be included in Acantho-
dactylus (see p. 296). Features present in all or most species are listed below.

1 . Frontal bones completely fused in adults and at least largely so in juveniles.

2. Often a fontanelle in the anterior wall of the orbit between the frontal and prefrontal

bones.

3 . A backwardly directed spur of jugal bone absent.

4. Parietal fontanelle present,

5. Parietal bone not projecting backwards over the supraoccipital.

6. Postorbital and postfrontal bones usually separate (fused only in A. cantoris).

7. Postorbital bone not filling supratemporal foramen.

8. Parietal and squamosal bones not usually in contact.

9. Pterygoid teeth present or absent (often considerable intraspecific variation).

1 0. Epipterygoid not usually in direct contact with pro-otic bone.

1 1 . Fourteen scleral ossicles present in each eye.

12. Scleral ossicle number 14 (following numbering system of Gugg, 1939) lacks a

radially directed peripheral section (see Fig. 1).

13. Number of presacral vertebrae ranges from 23 to 27, in most cases 23-26.

14. In the post-thoracic series of free dorsal ribs, the longer anterior ribs are fewer than

the shorter posterior ones.

1 5. Ribs on last presacral vertebra very reduced or absent.

294 E. N. ARNOLD

Fig. 1 Scleral ossicles of Acanthodactylus; arrow indicates scleral ossicle 14 which lacks a radially

directed peripheral section.

16. Sternum with a more or less heart-shaped fontanelle, which is sometimes divided

into left and right sections.

1 7. Sternal: xiphisternal rib formula 3 : 2 or less commonly 3:1.

18. Clavicle expanded medially with a large fenestra in this region, so that the bone

forms an uninterrupted loop.

19. Interclavicle cruciform, the lateral arms usually directed obliquely forwards.

20. Only the principal coracoid foramen present.

21. Caudal vertebrae of the C-type (Arnold, 1973: 305); that is, the most anterior

autotomic vertebrae have two pairs of transverse processes, the members of
the posterior one being longer and directed obliquely backwards.

22. Hemipenis and armature usually asymmetrical with medial side reduced (see

p. 300).

23. Hemipenis with an armature consisting of a flat intramuscular plate, one or two

clavulae and short connectors.

24. In species where the hemipenis and armature is not very reduced there may be more

than four connectors.

25. Nostril closable by a valve hinging on the posterior side of the opening.

26. Nostril nearly always situated between a postnasal, an internasal and the first upper

labial (not in A. guineensis, although the situation in this species is derivable
from that found in other Acanthodactylus, see Fig. 2).

27. First upper labial broad above but sides converge downwards (not in A. guineensis',

see comments about previous character).

28. Occipital scale reduced or, more usually absent.

29. A distinct collar of imbricate scales beneath neck.

30. Dorsals small and granular or larger, imbricate and keeled with rounded posterior

borders.

3 1 . Maximum number of ventral scales in a row across the belly varies from 8 to 1 8.

32. Toes with three longitudinal rows of scales around them and fingers with three or

four rows.

33. Subdigital lamellae keeled.

34. Lateral rows of scales on the toes and sometimes fingers forming pectinations.

35. Femoral pores present.

36. Tail more or less cylindrical, longer than body.

RELATIONSHIPS OF ACANTHODACTYLUS

295

Fig. 2 Right nasal regions of Eremias and Acanthodactylus'. (a) 'Eremias' ( = Acanthodactylus)
guineensis, adult: (b) Eremias nitida, adult: (c) 'Eremias'' ( = Acanthodactylus) guineensis,
juvenile: (d) Acanthodactylus erythmrus lineomaculatus, juvenile: (e) A. e. lineomaculatus,
atypical juvenile, BM 1966.430. Arrows indicate first upper labial scales.

Of these features, the following are probably derived, rather than primitive, within the
Lacertidae as a whole: 1,2,3,5,7,8, 10, 12, 15, 16, 21, 22,24, 25,27, 28, 31, 32, 33 and 34.
Only number 27 appears to be unique to Acanthodactylus but 22, hemipenial asymmetry
with the medial side of the organ reduced, is found elsewhere only in Philochortus Matschie,
1893 which, on other grounds, does not seem to be closely related. Monophyly is also
suggested by (i) the great similarity between the species of Acanthodactylus so that they are
interconnected by high levels of resemblance; (ii) possession of a unique combination of
derived features even if they themselves are not unique to the genus; (iii) a coherent geo-
graphical range.

The relationship of Acanthodactylus to other lacertids is difficult to judge outside the

296 E. N. ARNOLD

context of a comprehensive revision of the Lacertidae. Boulenger (1921) suggests that the
genus is related to Latastia Bedriaga, 1884 but the two share only a couple of the derived
features listed above, namely 1 and 33. Most derived features are shared with Eremias
Wiegmann, 1834 (used in the restricted sense of Shcherbak, 1974, for the Palaearctic species)
and Mesalina Gray, 1838 (used for the north African and southwest Asian species originally
referred to Eremias— see Arnold, 19806). Eremias shares 1, 2, 3, 7, 8, 14, 15, 16, 28, 32, 33
and often 25 and 34 while Mesalina shares 1, 2?, 3, 5, 7, 8, 10, 15, 16, 21, 33 and sometimes
28. More characters need to be examined before it can be decided which of these is likely to
be the sister taxon of Acanthodactylus or whether this is Eremias plus Mesalina.

Systematic position of Eremias guineensis

Eremias guineensis Boulenger, 1887a was described on the basis of a single hatchling,
supposedly from 'Brass, Mouths of Niger' (Nigeria). In fact, as Schmidt (1919) has already
suggested, this locality is almost certainly erroneous, or the result of accidental trans-
portation, for all the specimens collected since have come from places far to the north of
Brass in the Doka and Sudan woodland areas (vegetation classification of Rosevear, 1965) of
Nigeria and Ghana (BM(NH) specimens), Niger (Pappenfuss, 1969) and Cameroon. Material
from the latter country was described as a separate species, Eremias benuensis Monard, 1949
but Pappenfuss correctly synonymized this form with E. guineensis. The differences noted
by Monard (p. 740) result largely from comparing adult Cameroon animals with Boulenger's
description of a single juvenile, as is clearly apparent now that a number of adults are
available from Nigeria and other more western localities. The ostensible differences in head
and frontal scale proportions and relative head and leg lengths all result from allometric
changes during growth, and the supposedly distinctive conditions of the supraocular scales,
supraciliary granules and subnasal scale in E. benuensis can all be matched in E. guineensis
from Nigeria. Finally the supposed difference in pattern (six white stripes on dorsum in E.
benuensis and allegedly five in E. guineensis results from an error in Boulenger's description.

Boulenger placed E. guineensis in Eremias sens. lat. because it has the combination of fine
dorsal scaling, keeled subdigital lamellae and nostril separated from the first upper labial
scale that this author regarded as diagnostic of the genus. But he felt that this species
occupied an isolated position within the assemblage and assigned it to a new subgenus,
Taenieremias Boulenger, 19186. This separation of E. guineensis from the rest of Eremias
sens. lat. appears valid, for it differs in a number of features from the three main groups
included in Boulenger's concept of the genus. It can be distinguished from Eremias proper (a
Palaearctic assemblage) by having its postorbital and postfrontal bones unfused, by absence
of a radially directed peripheral section on scleral ossicle number 14, possession of C-type
caudal vertebrae, a reflectable collar and an asymmetrical hemipenis; from members of
Mesalina by absence of a radially directed peripheral section of scleral ossicle number 14,
absence of an occipital scale, possession of three rows of scales around the digits, which are
pectinate, and an asymmetrical hemipenis; and from the Ethiopian species usually referred
to Eremias and the probably related Meroles by C-type caudal vertebrae and an asym-
metrical hemipenis which differs in detail from any found in that group. It also differs from
the great majority of them in its heart-shaped sternal fontanelle and in absence of a
peripheral section of scleral ossicle 14 and of an occipital scale.

On the other hand, E. guineensis agrees with all the features of Acanthodactylus listed on
pp. 293-294 with the exception of the arrangement of scales around the nostril (features 26 &
27). Yet even here the situation in E. guineensis is not very like that found in species
assigned to Eremias sens. lat. and in size, shape and pattern of contact with each other, the
scales bear a close overall resemblance to those in Acanthodactylus, the only obvious
difference being the presence of an extra suture in E. guineensis running across the area
occupied by the first upper labial scale in Acanthodactylus to produce a smaller, nominal
first upper labial and a subnasal scale that is radically different in form from that found in

RELATIONSHIPS OF ACANTHODACTYLUS

297

members of Eremias sens. lat. (Fig. 2). Evidence that the E. guineensis condition is easily
derived from that found in Acanthodactylus is provided by a juvenile A. erythrurus
lineomaculatus (BM(NH) 1966.430) which, although normal in other respects, possesses an
extra suture that virtually duplicates the condition found in E. guineensis (Fig. 2e).

In addition to possessing the overwhelming majority of the features found in all or most
Acanthodactylus, E. guineensis bears a more detailed resemblance to A. boueti of north
Dahomy and Ghana and to A. erythrurus and A. savignyi of northwestern Africa (p. 318).
Given this degree of similarity, it seems best to transfer E. guineensis to Acanthodactylus, as
suggested elsewhere (Arnold, 1980/?).

Characters varying within Acanthodactylus

The following features may vary between species of Acanthodactylus and are therefore
potentially useful in defining species and in attempting to work out their inter-relationships.
Species names mentioned in the course of description are used in the senses employed
subsequently in this paper. A summary of many of the features is given in Tables 8 and 9.

Osteological characters

Shape ofthepremaxillary region (Fig. 3).

In many Acanthodactylus the outer edge of the premaxilla (viewed from above or below) is
smoothly continuous with those of the maxillae, but in some species this bone is abruptly
narrowed and there may be a slight constriction where its lateral surfaces meet the maxillae.

Fig. 3 Premaxillary regions of Acanthodactylus skulls from beneath: (left) A. erythrurus — outer
edge of maxilla and premaxilla smoothly continuous; (centre) A. schmidti premaxilla abruptly
narrowed; (right) A. scutellatus — premaxilla abruptly narrowed and premaxillary teeth reduced
to five, pm-premaxilla m-maxilla.

This condition is strongly developed in A. blanfordii, A. schmidti, A. arabicus, A.
gongrorhynchatus, A. haasi, A. masirae and especially the members of the A. scutellatus
group: it is at least indicated in many A. boskianus, A. cantoris and A. opheodurus. A smooth
lateral border to the anterior part of the skull is the usual condition in lacertids and the
narrowing found in some Acanthodactylus is almost certainly apomorphic. It is best
developed in species habitually living on soft sand. These forms usually have very acutely
pointed snouts and at least some probe the sand when hunting, perhaps in response to tactile
or aural cues originating from hidden invertebrates. Narrowing of the premaxilla may be
related to producing the acuminate snout-tip necessary for this activity.

Number of premaxillary teeth.

The usual number of premaxillary teeth in most Acanthodactylus species is seven with
occasional individual variation to six or eight. The three specimens of A. boueti checked are
singular in apparently having nine premaxillary teeth while many members of the A.

298 E. N. ARNOLD

scutellatus group have only five; this is true of the great majority of A. scutellatus and A.
longipes examined but of only a few A. aureus (see p. 328). As the number
of premaxillary teeth in most lacertids is about seven to nine, five seems likely to be an
apomorphic condition within Acanthodactylus. Its development may well be connected with
the narrowness of the premaxilla in these forms.

Postorbital and postfrontal bones.

These elements are separate in nearly all Acanthodactylus but they are fused in A. cantoris,

even juvenile ones.

Number ofpresacral vertebrae.

There are from 23 to 27 vertebrae between the skull and the sacrum in Acanthodactylus. The
interspecific variation encountered during this study is set out in Table 1. From this it will
be seen that, in most species, males usually have more presacral vertebrae than females, the
average difference in vertebral number between them varying from about 0-66 to 1-23. The
main exceptions to this are A. pardalis bedriagai and members of the A. scutellatus group
where average sexual differences are very small, ranging from —0-07 to 0-28. Although most
populations of A. schmidti show sexual differentiation in count, this is very reduced in
populations from the United Arab Emirates, eastern Arabia. In the majority of species, there
are 24 presacral vertebrae in most males and 25 in most females, but counts are higher in A.
(t.) tristrami, A. (t.) orientalis, A. robustus, A. erythrurus, A. savignyi, A. boueti and A.
guineensis: here males typically have about 25 presacral vertebrae against usually 26 or even
27 in females. A. pardalis bedriagai generally has 26 vertebrae in both sexes while in male
and female A. schmidti from the United Arab Emirates, A. scutellatus and A. aureus average
counts approach 24; the average is even lower in A. longipes and in some parts of its range
may be around 23.

Nearly all other lacertids show marked sexual variation in vertebral number, so its
reduction is likely to be apomorphic. Counts of 23 in males and 23 or 24 in females are at the
lower limit for lacertids as a whole and may well be derived conditions. Other counts are well
within the normal range for the family but the higher ones, 25 in males, 26 or 27 in females,
may possibly also be apomorphic as they commonly occur only in a minority of forms which
on other grounds may be closely related.

In general, species with high presacral vertebral counts are found in relatively mesic
habitats while those with low vertebral numbers occur in drier, more open places with
sparser vegetation. It may be that the former habitat type requires more body flexion in
passing through plant cover and more vertebrae facilitate this. Certainly in lacertids as a
whole there is a distinct if imprecise correlation between vertebral number and habitat
structure.

The selective pressures that cause loss of sexual differentiation in vertebral number are
obscure. Possibly the difference in average count found in most lacertids reflect sex-
correlated difference in microhabitat, males might, for instance, spend more time in open
situations than females. If this were so, uniformity of vertebral number might result from
lack of such microhabitat differences, something that seems quite probable in the relatively
uniform, open environments occupied by A. schmidti and the A. scutellatus group. Another
possibility is that the extra vertebrae of most female lacertids increase the length of the body
cavity for carriage of eggs and that loss of sexual differentiation is a correlate of small clutch
mass. However, although egg number in the A. scutellatus group at least is quite small (n = 2
or 3) there is no clear evidence that a clutch occupies a smaller proportion of the body cavity
than in most other species of Acanthodactylus.

Sternal ribs.

In the great majority of Acanthodactylus species the usual sternal rib formula is 3 : 2, that is
three pairs of ribs attach directly to the sternum and two to the xiphisternum. However, in
nearly all of these, the fifth sternal rib is interrupted on at least one side in a minority of
individuals, albeit often only briefly. In contrast, interruption is the commoner condition in

RELATIONSHIPS OF ACANTHODACTYLUS

299

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intra muscular portion of armature

medial connectors

upper surface of
lateral clavula

TS of lateral clavula

lateral connectors

upper surface of
medial clavula

TS of medial clavula

medial clavula

lateral lobe

reflexed lateral
sulcal lip

medial lobe

reflexed medial sulcal lip

medial lip of sulcus

sulcus

lateral lip
of sulcus

Fig. 4 Left armature and uneverted hemipenis of Acanthodactylus micropholis, diagramatic view
from below, the base of the hemipenis is at the bottom of the illustration. The m. retractor penis
magnus and ventral wall of the hemipenis have been removed, the flattened hemipenial lobes
spread out and the armature disconnected: normally the points marked A coincide, with the
armature lying largely above and behind the retracted hemipenis.

members of the A. pardalis and A. scutellatus groups, sometimes overwhelmingly so (Table
1 .) Furthermore, the fifth sternal rib is frequently reduced to quite a small vestige.

Hemipenial characters

Like many other lacertids, Acanthodactylus has a hemipenis with an armature, that is a
discrete and complex supporting structure of dense connective tissue situated mainly in and
around the penis retractor magnus muscle. Its basic anatomy and that of the lacertid

RELATIONSHIPS OF ACANTHODACTYLUS

d e f

Fig. 5 Uneverted left hemipenes of Acanthodactylus spp. showing variation in form and
symmetry. In all except (b), the lobes are flattened and normally complexly folded, but they have
been spread out for illustration, (a) lobes subequal (A. micropholis); (b) lobes subequal but
tubular and unflattened (A. cantoris); (c) medial lobe somewhat reduced (A. blanfordii. A.
pardalis generally similar); (d) medial lobe very small (some A. (t.) orientalist (e) medial lobe
minute, lateral lobe large (e.g. A. schmidti); (f) medial lobe absent, lateral lobe extremely large
(e.g. A. scutellatus).

hemipenis in general are described elsewhere (Arnold, 1973; and in press) but Fig. 4 shows
the salient features in Acanthodactylus. A number of variations between species are
described below, and are illustrated in Figs 5 and 6.

Size.

Hemipenes are small in A. cantoris, A. boueti, A. maculatus and A. spinicauda.

Asymmetry in the lobes of the hemipenis.

In many species, the two lobes are subequal in size but in others the medial lobe is reduced
while the lateral one increases in size and becomes more fan-like in the uneverted organ. The
amount of medial reduction varies and in some cases the medial lobe is absent or minute.

Lobes subequal: A. micropholis, A. cantoris, A. boskianus, A. schreiberi, A. grandis
complex, A. (t.) tristrami, A. robustus, A. erythrurus, A. savignyi, A. boueti.

Medial lobe somewhat reduced: A. blanfordii.

Medial lobe more strongly reduced: A. pardalis, some A. (t.) orientalis.

Medial lobe very small: some A. (t.) orientalis.

302

E. N. ARNOLD

Fig. 6 Left armatures of Acanthodactylus species. Main views from beneath; arrangement of
distal views of clavulae and of their transverse sections as in Fig. 4: (a) A. cantoris: (b) A.
blanfordii', (c) A. schmidti; (d) A. arabicus', (e) A. gongrorhynchattus; (f) A. (t.) tristrami.

A number of species have generally similar armatures to A. (t.) tristrami but differ mainly in
the form of their lateral clavula, consequently in (g)-(j) only this is shown, ventral and dorsal
views and a cross section being given: (g) A. robustus', (h) A. grandis; (i) A. boskianus; (j) A. e.
erythrurus, A. pardalis; (k) A. (t.) orientalis; (1) A. guineensis\ (m) A. maculatus; (n) A. scutellatus',
(o)A. opheodurus.

Medial lobe minute or absent: A. schmidti, A. arabicus, A. gongrorhynchatus, A. haasi, A.
guineensis, A. maculatus, A. spinicauda, A. aureus, A. longipes, A. scutellatus, and the A.
opheodurus group.

Lobe shape.

In most Acanthodactylus, the hemipenial lobes are flattened and fan-shaped, but complexly

folded in the uneverted organ. However, in A. cantoris they are narrow and tubular.

Form of the proximal lip of the medial branch of the sulcus.

This is usually well developed and flap-like in species where the medial side of the hemi-

RELATIONSHIPS OF ACANTHODACTYLUS 303

penis is relatively large, although it is usually reduced in forms where this is not so. A.
boskianus, A. schreiberi and A. grandis are exceptional in having a well-developed median
lobe but a weak proximal lip to the medial branch of the sulcus.

Reduction of the medial side of the armature.

In most species, the medial side of the armature is reduced in size, simpler in form than the
lateral side and indeed may be entirely absent. The extent to which this reduction occurs
varies and shows some correlation with reduction of the medial lobe of the hemipenis,
although how precise this is varies.

Sides subequal: A. micropholis, some A. cantoris.

Medial side somewhat reduced: some A. cantoris, A. boskianus, A. schreiberi, A. grandis
complex, A. (t.) tristrami, A. robustus, A. erythrurus, A. savignyi, A. boueti, A. pardalis.

Medial side more strongly reduced: A. blanfordii, some A. schmidti, A. (t.) orientalis.

Medial side reduced to a thread or absent: most A. schmidti, A. arabicus, A. gongrorhyn-
chatus, A. haasi, A. guineensis, A. maculatus, A. spinicauda, A. aureus, A. scutellatus, A.
longipes, A. opheodurus, A.felicis, A. masirae.

In these forms the medial branch of the sulcus is short or absent.

Shape of the medial clavula.

In species where a medial clavula is present there are two main patterns.

Clavula fairly broad, flat and blunt-tipped with at least the inner edge turned upwards: A.
micropholis, A. cantoris, A. blanfordii and some A. schmidti.

Clavula narrow and pointed with a ^ -shaped cross section: A. boskianus, A. schreiberi, A.
grandis complex, A. (t.) tristrami, A. robustus, A. erythrurus, A. savignyi, A. boueti, A.
pardalis.

In A. (tristrami) orientalis the median clavula is like this or very small and flattened.

Shape of lateral clavula.

Substantial differences are found in the form of this structure.

1 . Simple, flattened, often with one or both edges turned dorsally: A. micropholis, A.
cantoris, some A schmidti, A. robustus, A. opheodurus, A.felicis, A. masirae.

2. Not flattened, blunt, edges folded dorsally, a central lobe on the upper surface with a
proximally directed pocket: A. blanfordii, many A. schmidti.

3. Very narrow, hollowed above: A. arabicus, A. gongrorhynchatus (A. haasi has a similar
but shorter lateral clavula).

4. Complexly structured with multiple lobes below: A. boskianus, A. schreiberi (most
medial lobe often single), A. grandis complex (most medial lobe often divided).

5. Complexly structured although not conspicuously lobed below, sometimes very
slightly bifurcate: A. (t.) tristrami.

6. Complexly structured and not conspicuously lobed below but clearly bifurcate at tip: A.
(t.) orientalis, A. erythrurus, A. savignyi, A. boueti, A. pardalis.

1. Lateral clavula simple but often bifurcate and folded to give a D-shaped cross section:
A. maculatus, A. spinicauda.

8. Lateral clavula flattened and not bifurcate but folded to give a ID-shaped cross section:
A. aureus, A. scutellatus, A. longipes.

Connectors.

In some species the connectors are all relatively thin but in others the most medial one on the
lateral side is usually thickened. This is found in A. boskianus, A. schreiberi, the A. grandis
complex, A. (t.) tristrami, A. (t.) orientalis. A. robustus, A. erythrurus, A. savignyi, A. boueti,
A. guineensis, A. pardalis, A. maculatus and A. spinicauda.

Polarity of hemipenial features

The only available criterion for the polarity of hemipenial features found in Acanthodactylus
is outgroup comparison using other lacertids as the outgroup. In these, the hemipenis is

304 E. N. ARNOLD

usually fairly large and symmetrical with well developed sulcal lips on both sides. Where
present the armature is also typically symmetrical with simple, often flattened and rather
blunt clavulae. On this basis, small size, asymmetry of the lobes, sulcal lips and armature and
the development of peculiar and often complex clavulae and thickened connectors are all
likely to be derived features.

Origin of hemipenial differences

It is common in many animal groups for genital structure to vary between taxa and for at
least some of its features to be considered good indicators of relationship, especially as they
often correlate with characters from other organ systems. The origin of such differences and
possible reasons why they should often reflect relationship are discussed at length elsewhere
(Arnold, 1973; in press). It is suggested that genitals differ from other organ systems in their
potential to retain changes that develop in them as a result of pleiotropic effects or transient
selective forces. With most organ systems, any pleiotropically induced change is likely to
result in a loss of functional efficiency. Provided this lowering or efficiency does not
outweigh the original selective advantage of the genetic change concerned, the pleiotropic
alteration will initially become fixed. But there will then be normalizing selection modifying
the genotype so that the pleiotropic change will tend to be suppressed and the organ will
return to its original state and level of efficiency. Similarly, if the organ changes in response
to direct but transient selective pressure, it will tend to revert to its original condition once
this pressure is relaxed.

The situation with genitalia is different since their efficiency cannot be considered in
isolation but only in relation to their co-ordinated functioning with the genitals of the
opposite sex. Efficiency does not depend on a particular conformation or size but on good
match between the sexes. Consequently, if there were, say, a pleiotropic change affecting the
male organs which reduces copulatory efficiency, there would not only be normalizing
selection acting on the male genotype to bring the male organ back towards its original
condition but also, simultaneously, selection acting on the female genotype to produce
genital changes adapting to the pleiotropic alterations that have already taken place in the
male system. This means that the two sets of genitals might return to their previous mutual
efficiency without reverting to their original morphological state. The same sort of effect
would be expected if transient selective forces acted directly on the genitalia themselves.
Genitals are thus likely to 'store' changes, which in other organ systems would probably be
eradicated. So they may be on the whole more likely to incorporate evidence of shared
evolutionary experience than many other organs.

An important factor in the production of hemipenial differences in lizards, including
Acanthodactylus, may be the development of physical isolating mechanisms when pre-
viously allopatric species come into contact. Such isolating mechanisms could reduce the
loss of reproductive effort which is likely if two species interbreed. That such loss can occur
is evidenced by the occasional discovery of hybrids between lacertid species (cases in Lacerta
and its relatives are summarized by Arnold, 1973, and in Acanthodactylus by Mertens,
1968). Physical isolating mechanisms would be at a premium in situations where similar
species with no experience of each other come into contact since, in this situation,
premating isolating mechanisms may not be well developed. Interspecific mating would be
reduced if considerable mismatch evolved in the shape and dimensions of the genitalia of the
forms concerned. The often radically different hemipenes of otherwise similar species of
Acanthodactylus may be examples of this, especially as they correspond in shape and size to
the cloacal bursa of their own females into which the male organ is inserted. Such differences
occur between forms which, on other grounds, are likely to be closely related, for instance
Acanthodactylus pardalis and A. maculatus and, because they reduce the possibility of
successful copulation between the forms, are prima facie evidence of separate species status.
Some of the derived features found in the hemipenes of Acanthodactylus can be interpreted
as contributing to such isolating mechanisms; they include not only small size but also

RELATIONSHIPS OF ACANTHODACTYLUS 305

asymmetry of the hemipenis and armature since loss of its medial side reduces the diameter
of the organ.

Although they are likely to be 'stored' beyond their period of function (presumably
premating isolating mechanisms are likely to develop in the long run), changes that are
probably associated with physical isolating mechanisms are not likely to be very reliable
indicators of relationship. This is partly because, by their nature, they tend to produce
marked differences between very similar and often closely related species. Also, means of
producing incompatible genitalia are rather restricted in lizards and it is very likely that
small size and asymmetry may have been produced several times. This is supported by their
patchy occurrence in Acanthodactylus, turning up in a number of groups which on other
grounds do not seem to be closely related. Furthermore these features have developed in
other lacertid genera. Other hemipenial features may not be subject to such strong
convergent selective forces and, as such are more likely to be good indicators of relationship
for the reasons given earlier in this discussion.

Description of the hemipenes of different species

Figures in parentheses refer to the number of individual organs examined.

A. micropholis (2). Lobes more or less symmetrical or medial rather reduced, sulcus
bifurcate, the proximal borders of its branches formed by backwardly directed flaps;
armature fairly symmetrical although one or other clavula larger than the other, clavulae
rather expanded and obtusely pointed, the medial one with its inner edge turned upwards,
lateral one with both edges turned upwards; often three lateral connectors and two medial
ones, all narrow.

A. cantoris (7). Size reduced; medial lobe usually rather smaller than lateral, lobes not
complexly folded, the walls often corrugated and lack regular plicae, stem of hemipenis long,
sulcus bifurcate, the proximal borders of its branches formed by a soft flap in at least some
cases although this is not always clear; armature symmetrical or medial side somewhat
reduced, slender, the clavulae expanded and laminar, medial with inner edge turned
upwards, lateral with both edges turned upwards, at least one connector on each side.

A. blanfordii (10). Lateral lobe large and medial one reduced, sulcus bifurcate, proximal
border of lateral but not medial side formed by a backwardly directed flap; armature clearly
asymmetrical, the median side reduced with a flattened clavula of which the inner edge is
turned upwards, lateral clavula large and obtusely pointed, not flattened, edges turned
upwards and a central lobe present on the upper side below which there is a proximally
directed pocket (the lobe is least developed in southern populations), connectors as in A.
micropholis.

A. schmidti (10). Lateral lobe large and fan-shaped, medial lobe absent or minute, sulcus
bifurcate but medial branch very short; medial side of armature absent or reduced to a thread
in most cases; lateral clavula large, either rather pointed, slightly bifurcate or rather blunt,
edges turned upwards and clavula may be rolled to some extent, a central lobe present in
many cases on the upper side, below which is often a proximally directed pocket as in A.
blanfordii but is less well developed. In one case (BM(NH) 1931.7.16.48) there is a flattened
medial clavula.

A. arabicus (6). Essentially like A. schmidti but intramuscular part of armature much
narrower and lateral clavula very narrow, simple and pointed with a concavity above or the
medial edge rolled upwards.

A. gongrorhynchatus ( 1 ). Similar to A. arabicus but medial edge of clavula rolled onto dorsal
surface.

306 E- N. ARNOLD

A. haasi (1). Like A. gongrorhynchatus but clavula shorter, broader and more dorso-
ventrally flattened.

A. (tristrami) tristrami (3). Lobes more or less symmetrical, sulcus bifurcate, the proximal
borders of its branches formed by distinct flaps; armature asymmetrical, the medial side
reduced with a pointed clavula that has a ^ -shaped cross section; lateral clavula expanded
and, when spread out, essentially flat with a very weakly bifurcate tip formed of overlapping
laminae, lower surface fairly smooth but with a strap-shaped area with free edges towards
outer side, upper surface with a medially directed pocket and edges rolled upwards; three
lateral and two medial connectors, the more medial of the lateral ones thickened.

A. (tristrami) orientalis (4). Different from A. (t.) tristrami: lateral lobe very large and medial
strongly reduced (as in Fig. 5c or d), sulcus bifurcate, proximal borders of branches formed
by distinct flaps, the median one rather small; armature very asymmetrical, medial clavula
quite small, either pointed with a <= -shaped cross-section or blunt and flattened; lateral
clavula rather similar to that of A. (t.) tristrami and has free strap-shaped area on lower
surface but is smaller with a more bifurcate tip and no clear pockets.

A. robustus (2). Generally like A. (t.) tristrami but lateral clavula much simpler with edges
turned on to dorsal surface.

A. boskianus (10), A. schreiberi (5). Generally like A. (t.) tristrami but proximal border of
medial branch of sulcus is a relatively weak, soft fold rather than a flap; lateral clavula has
similar general form but is more swollen and lobed and there is an area with free edges
towards the medial side of the ventral surface; upper surface has medial edge rolled upwards
and greatly swollen. In A. schreiberi and A. boskianus the median area of the ventral surface
may be divided by a longitudinal cleft.

A. erythrurus erythrurus (3), A. e. lineomaculatus (3), A. savignyi savignyi (2), A. s. bland
(2). Similar to A. (t.) tristrami but lateral clavula usually clearly bifurcate at tip and the more
median cleft in A. (t.) tristrami, that separates a strap shaped area with free edges in this form,
is usually not clearly marked.

A. e. belli (6). As A. e. erythrurus but lateral clavula is smaller, flatter and usually simpler.

A. boueti (1). Size reduced; lobes subequal; armature asymmetrical, the medial side reduced
with a pointed clavula that has a <c -shaped cross section; lateral clavula expanded and
flattened, bifurcate at tip, with lateral edge turned upwards.

A. guineensis (1). Lateral lobe very large, medial lobe absent, sulcus lacks medial branch,
proximal border of its lateral branch formed by a backwardly directed flap; medial side of
armature absent, lateral clavula superficially narrow but in fact laminar and tightly rolled,
lower surface smooth but with a cleft near each margin, dorsum with a medially directed
pocket; two connectors, the more medial one broad.

A. pardalis (20). Lateral lobe large and medial small but plicate, sulcus bifurcate, the
proximal border of its branches formed by backwardly directed flaps; armature very like that
of A. erythrurus and A. savignyi.

A. maculatus (20), A. spinicauda (2). Small; lateral lobe large, medial lobe absent; medial
branch of sulcus very short, proximal border of lateral branch only of sulcus formed by back-
wardly directed flap; medial side of armature absent or reduced to a thread, lateral side
narrow and clavula small but sometimes bifurcate; compared to condition in A. pardalis,
lateral clavula has been rotated and folded to give a ^-shaped cross section so that the
bifurcation, if present, is in the vertical plane; two or three connectors, the most medial one
usually thickened.

A. aureus (3). Lateral lobe large and fan-shaped, medial lobe absent or very small and
confluent with lateral one, medial branch of sulcus absent or very short; medial side of

RELATIONSHIPS OF ACANTHODACTYLUS 307

armature absent or reduced to a thread, lateral side broad; lateral clavula flattened but
rotated sideways, as in A. maculatus, and folded to give a D -shaped cross section, with two
connectors.

A. scutellatus (5), A. longipes (3). Generally similar to A. aureus but folded clavula usually
broader and sometimes apparently only one connector present.

A. opheodurus (10), A. felicis (4), A. masirae (2). Lateral lobe extremely large, medial one
very reduced, sulcus with relatively short medial branch, proximal border of lateral branch
usually visible as a rather weak flap or fold; medial side of armature reduced to a thread or
absent, lateral clavula usually flattened with the margins rolled over onto dorsal surface;
lateral connectors usually two or sometimes three, slender.

External features

These have nearly all been used by Boulenger (1918a, 1921) and subsequent authors and,
until now have formed the basis of Acanthodactylus classification.

Scales around nostrils.

A. guineensis has a peculiar perinasal scale arrangement that seems to be derived from the
typical Acanthodactylus condition, it also occurs as a rare variant in A. erythrurus (see
p. 296).

Frontonasal scale.

This is usually intact but is frequently divided in two by a longitudinal suture in some

populations of A. erythrurus and A. savignyi. The condition occurs as a rarity in a few other

species.

Azygos scales between prefrontals.

One or more azygos scales between the prefrontals occurs commonly in A. boueti, A.
savignyi and in some populations of A. erythrurus. This arrangement is also found as an
uncommon variant in A. guineensis, A. schreiberi and A. boskianus and even more rarely in
some other forms.

Supraocular scales.

There is considerable variation in the extent to which the supraocular scales roofing the orbit
are fragmented in Acanthodactylus. 1. A. schreiberi has four large, more or less intact scales;
this condition is approached by members of the A. grandis complex. 2. In the A. cantoris, A.
scutellatus and A. opheodurus groups and in A. gongrorhynchatus, A. haasi and many A.
boskianus there is usually an area of granules wedged between the third and fourth supra-
oculars and, in some cases, between the first and second too; the fourth supraocular may also
be broken up, at least to some extent. A. boskianus from north Egypt and A. haasi may
have the first supraocular divided into two or three sections. 3. Members of the A.
pardalis group have the first supraocular sometimes divided into two or even three and the
fourth is very fragmented. 4. In the A. tristrami and A. erythrurus groups the first supraocular
is divided into at least three sections and often into many granules and this usually applies to
the fourth too. 5. A. boueti has the first, second and third supraoculars all fragmented. There
is however a significant amount of variation within taxa.

It is probable that the plesiomorphic condition is four more or less undivided supraocular
scales, as this is by far the commonest state in the Lacertidae as a whole, but fragmentation
seems to have occurred independently in some forms assigned to Eremias and in Ichnotropis.

Subocular scale.

A number of species have a subocular scale that extends ventrally to the edge of the mouth,
separating the, in these cases, usually four anterior upper labial scales from the remainder.
This condition is found in A. (t.) tristrami, A. (/.) orientalis, A. masirae, A. boueti and A.
guineensis, in many A. micropholis, A. erythrurus and A. savignyi, in a few A. boskianus
from the Iraq region and in occasional examples of some other species such as members of

308 E. N. ARNOLD

the A. pardalis group and A. opheodurus. Elsewhere the subocular is shallower and the upper
labials form a continuous series beneath it. The former state is likely to be plesiomorphic as
it is very widespread in the Lacertidae as a whole, but the latter occurs in Eremias proper, in
some species usually assigned to Eremias from the Ethiopian region and in Meroles Gray,
1838, Aporosaura Boulenger, 18876 and Ichnotropis Peters, 1854. The supposed apomor-
phic condition may apparently arise by the subocular becoming increasingly narrowed
ventrally or by splitting to produce a small ventral scale that forms an extra upper labial.

In general, the subocular is separated from the lip in forms from drier, more open habitats
which tend to have particularly large eyes and the character may be at least partly a
functional correlate of this size increase. In species where the subocular scale usually borders
the mouth, the lateral surface below the anterior eye, formed from the jugal and maxillary
bones, tends to be fairly vertical, so that the scale can cover it but still remain roughly in the
same plane as the upper lip of which its lower section forms part. But, with increase in eye
size, the jugal arch bulges outwards and its outer face and that of the section of the maxilla
below it is directed more obliquely downwards. In this situation, a single scale covering this
surface and forming part of the lip would be strongly bent and possibly not able to provide
the necessary flexibility for labial movement. In forms living in dry areas, the need for such
movement is increased, for the upper lip projects further ventrally and is more bulky, so it
and the scales covering its outer surface are displaced more during closure of the mouth,
presumably producing a more efficient seal against water loss and incursion of sand particles
than is present in more mesic species. Because of these changes, the replacement of the
original subocular by two functional parts would probably be an advantage.

Number of upper labial scales anterior to the centre of the eye.

In the majority of forms there are typically four upper labials anterior to the centre of the eye
but in some, such as the members of the A. cantoris group, A. scutellatus and A. longipes, five
is the usual number. As four is found in forms which on other grounds seem primitive, it may
be the plesiomorphic condition for Acanthodactylus. When present, the extra upper labial
sometimes seems to develop by being split off the subocular but this may not always be its
origin. In many species exceptions to the usual number occur.

Parietal scales.

A. boueti is singular in having the parietal scales reduced and the areas normally occupied

by their lateral and posterior parts replaced by small scales.

Ear opening.

This is usually quite large but in A. gongrorhynchatus and A. haasi it is reduced in size, being
occluded by skin from above and from the front. Similar reduction is found in some other
lacertids that live on loose sand such as Aporosaura and some species of Meroles.

Dorsal body scales.

There is great variation in size and shape of the dorsal scales. In many species they are fine
and more or less granular and either smooth or carinate, but in others size increases
posteriorly and the scales become flat, more keeled and strongly imbricate. In such cases, the
lateral scales tend to be smaller than the more medial ones. Transverse counts at mid-body
may be as high as 100 in the most fine-scaled species, A. longipes, or as low as 18 in some A.
boskianus asper. There is often substantial variation within and, more obviously, between
populations of a species; thus counts vary from about 35 to 80 in A. scutellatus and from 1 8
to 52 in A. boskianus. This suggests that dorsal scalation is very labile so that the assessment
of a primitive condition for the genus is impossible. All that can be said is that the extremes
encountered in Acanthodactylus are near the extremes for the Lacertidae as a whole and that
the primitive condition is perhaps more likely to be somewhere in between.

In some other sections of the Lacertidae, relatively fine granular scaling is usually
associated with open environments while, large, keeled, strongly imbricate scales are
typically found in species that live, or at least take refuge in, dense often spiny vegetation.

RELATIONSHIPS OF ACANTHODACTYLUS 309

The latter scale arrangement provides much better mechanical protection against damage to
the flexible skin between the scales, something that is potentially likely to occur when
running in densely vegetated habitats. The same selective pressure may well act on
Acanthodactylus; the most fine-scaled forms, like many populations of the A. scutellatus
group, tend to live in the most open habitats, whereas forms like A. boskianus do frequently
seem to take refuge in spiny vegetation (see p. 3 1 5).

Dorslateral tracts of enlarged scales.

These are found on the posterior body of A. schmidti and are at least indicated in some A.

blanfordii.

Ventral scale number.

The number of ventral scales in the longest transverse row across the belly varies from about
8 to 18, 10 being the commonest figure. As the majority of lacertids have low numbers, these
are likely to be primitive in Acanthodactylus. In general low numbers are most frequent in
forms occupying more mesic habitats and higher ones in species living in relatively arid
areas, but this correlation is imprecise. Intraspecific variation occurs, especially in forms
with higher counts.

Tessellation of ventral scales.

Forms with high transverse counts of ventrals often have the scales tessellated, that is, they
are staggered so that they do not form regular longitudinal rows. In many cases, this
staggering is confined to the sides of the belly, but it may affect the median areas too. It is best
and most extensively developed in most populations of the A. scutellatus group and in the A.
grandis complex; it is found to a lesser extent in other members of these assemblages and is
at least indicated in the A. cantoris group and A. gongrorhynchatus. There is significant
variation in the extent of staggering within species where it is present. Tessellation is found
in some other lacertid groups such as Eremias proper, Meroles and Aporosaura.

Inter gradation of dorsal and ventral scales.

In most Acanthodactylus, dorsal and ventral scales are easily distinguished from each other,
but in A. gongrorhynchatus they intergrade. This trend is also apparent in A. haasi and to a
lesser extent in some A. arabicus.

Number of rows of scales running along fingers.

In many species there are three rows of scales running along fingers one to four, the same
number that runs along each toe. One row is dorsal, one ventral and the third posterior. On
finger five, and sometimes at the base of the others, there may be four rows, the additional
one being anterior. In contrast, a number of forms have four regular and continuous rows of
scales on all fingers; these include the A. cantoris and A. scutellatus groups, the A. grandis
complex, A. gongrorhynchatus and A. haasi. In fact, these two conditions are not as clear cut
as they appear, for a number of individuals of species that usually have three scale rows
possess additional scales forming an irregular fourth row on at least some fingers; this occurs
in A. micropholis, A. robustus and A. opheodurus. A. masirae habitually has four rows but
these are often irregular, and A. cantoris in which four regular rows are usually present
occasionally has the anterior one strongly reduced.

It seems likely that three scale rows running along the fingers is the primitive condition in
Acanthodactylus for it comes closest to the two rows typical of the majority of Lacertidae and
other scincomorph lizards. Three or four scale rows on the fingers also occur in Eremias
proper, Meroles and Aporosaura. The presence of a regular fourth row is largely associated
with sandy habitats. It may well allow better development of a pectination on the anterior
face of the digit that matches the posterior one. This results in a wider digit that is more
efficient for digging in light, unconsolidated substrates such as fine sand where
Acanthodactylus often scrabbles for food as well as excavating burrows.

310 E.N.ARNOLD

Pectination of the digits.

The scales along the posterior surfaces of the digits are pointed and project to form a comb-
like fringe or pectination. In some instances, this is inconspicuous but in others the scales
become very long and flattened in the horizontal plane and in extreme cases, such as A.
longipes, the fringe on the toes may be wider than the digits themselves. The scales forming
the row running along the upper surfaces of the digits may project slightly forwards to
produce a weak anterior fringe as well, but in species where there is an anterior scale row on
the fingers, this may form a fringe approaching the posterior one in development.

There is a continuum between the weakest fringes and the most pronounced ones. Degree
of development correlates very closely with what is known about the ecology of the species
concerned, being least in forms living on relatively hard ground and greatest in forms from
soft sand. The relationship is so strong in taxa for which some ecological information is
available that it seems reasonable to use degree of pectination to predict substrate type in
cases where this is unknown. The importance of fringes on the fingers for digging in loose
sand has already been mentioned; fringes also enable lizards to travel across soft sand
surfaces efficiently by increasing the area covered so that unit pressure is low and effort is not
wasted pushing the sand backwards as the lizard moves forwards.

Keeling on upper caudal scales.

Most Acanthodactylus, like the majority of lacertids, have keels on the dorsal scales of the tail
base but these are absent in A. (/.) tristrami, A. (t.) orientalis and A. robustus. The restricted
distribution of this feature in the Lacertidae suggests it is an apomorphy, although it has
developed independently elsewhere, for instance in Mesalina rubropunctata.

Lateral processes on tail base.

In A. spinicauda the lateral scales at the base of the tail are greatly enlarged, especially in

males, with their keels produced to form tubercles. This feature is unique in the Lacertidae.

Tail length.

In most Acanthodactylus the tail is more than 1-5 times the length of the head and body

together but in A. (t.) tristrami, A. (t.) orientalis and A. robustus it is less.

Pattern.

In the great majority of Acanthodactylus species, juveniles have a striking pattern of narrow,
dark and light longitudinal stripes. The only certain exceptions are A. schmidti, A. longipes
and some A. scutellatus in which the newly hatched young are uniform or dappled. This
condition is likely to be derived as striped patterns are very widespread among juvenile
lacertids. When present, the number of dark stripes varies considerably and there may be as
many as six pairs, although not all these run the whole length of the body. In the no-
menclature of Lantz (1928), developed for Palaearctic Eremias, these are 1. the spinal
originating near the mid-line and usually fusing to produce a single stripe on the body, 2. the
occipital arising from the hind edge of the parietal scale, 3. the parietal arising from the
lateral edge of that scale, 4. the temporal beginning behind the eye and passing over the
upper edge of the ear (equivalent to Lantz's upper and lower temporals), 5. the maxillary
passing through the ear and 6. the costal passing below it.

It is usually acknowledged that a high number of stripes is plesiomorphic in the Lacertidae
(Eimer, 1881; Boulenger; 1921; Lantz, 1928) and this condition is certainly commoner in
forms which on other grounds seem primitive. Reduction in number seems to take place
most usually by loss or fusion of bands at the mid-line. As we have seen, a few Acantho-
dactylus have a pair of spinal bands on the neck that fuse on the body; reduction from this
state appears to follow a clear sequence: 1. the spinals fuse throughout their length; 2. the
resultant composite stripe shortens while the occipital stripes fuse posterior to it; 3. the
spinal stripe is reduced to a vestige or disappears and fusion of the occipitals extends for-
wards; 4. the occipitals fuse completely to produce a simple mid-line stripe. This means of
course that mid-line stripes in Acanthodactylus are not always homologous as they can be

RELATIONSHIPS OF ACANTHODACTYLUS 3 1 1

composed either of fused spinal bands or of occipitals. There may also be loss of the outer-
most bands, especially the costals on the body.

Presence of a pair of spinal stripes on the neck is largely confined to some A. micropholis,
A. erythrurus and A. pardalis. The partial development of a mid-dorsal stripe made up of the
occipitals occurs in some individuals of the following species: A. boskianus, A. schreiberi, A.
pardalis, A. scutellatus, A. opheodurus, A. felicis and A. masirae, but complete fusion seems
to be confined to some A. boskianus and A. scutellatus and most A. opheodurus.

A. micropholis retains a simple striped pattern throughout life. In other forms this is often
modified, but predominantly striped individuals, or ones with longitudinal rows of spots, are
common in most species. However not all the stripes present in juveniles may be discernible
in these adults.

A. pardalis and A. maculatus are singular in that some individuals of each have spots of
brownish red pigment on their backs that do not fade or disappear in alcohol.

In A. (t.) tristrami, A. (t.) orientalis and A. robustus some individuals have two rows of large
ocellar markings along the back.

Species boundaries and species groups

The introduction of osteological and especially hemipenial characters provides a partial test
of the homogeneity of the species presently recognized within Acanthodactylus. For even if
the external features on which these nominal taxa are based show little obvious variation,
discontinuity in characters from the new sources may indicate that more than one form is
involved. The species are mostly discussed below in groups that consist of species with a high
level of overall similarity and which, in most cases, probably form holophyletic assemblages,
although there are exceptions.

A. micropholis

A. micropholis Blanford, 1874a, occurs in southeast Iran and southwest Pakistan, in the
latter country occupying sandy places along water courses in hilly areas (Minton, 1966). It
has a high proportion of primitive features including the following: premaxilla with about
seven teeth and not abruptly narrowed, 24 presacral vertebrae in males and 25 in females,
sternal ribs usually intact; hemipenis and armature fairly symmetrical, clavulae flattened and
simple, connectors slender; subocular often reaching mouth, frequently four upper labials
anterior to centre of eye, eight or ten ventrals in longest row across belly, ventrals arranged in
straight longitudinal rows, usually three longitudinal rows of scales on fingers, pectination on
digits rather weak, upper caudal scales keeled, young with numerous dorsal stripes which are
retained by adults. On the other hand, the first and fourth supraoculars are broken up and, in
some individuals, the subocular may be separated from the mouth, five upper labials are
sometimes present anterior to the centre of the eye and there may be indications of a fourth
scale row on the fingers.

The A. cantons group, A. gongrorhynchatus and A. haasi

A. cantons Giinther, 1864ft: NW. India, Pakistan, E. Afghanistan.

A. blanfordii Boulenger, 191 8a: S. Afghanistan, SW. Pakistan, SE, Iran, Oman (Muscat area).

A. schmidti Haas, 1957: Arabia except extreme west; SW. Iran (Anderson, 1963, 1974).

A. arabicus Boulenger, 1918a: SW. Arabia.

A. gongrorhynchatus Leviton & Anderson, 1967: E. and SE. Arabia.

A. haasi Leviton & Anderson, 1967: E. Arabia (Dhahran).

The first four forms, which constitute the A. cantoris group, are all associated with loose
sand habitats (A. cantoris— Minton, 1966; Mertens, 1969, A. blanfordii— Blanford, 18746;
Anderson, 1963; Clark et ai, 1969; M. D. Gallagher, pers. comm. A. schmidti— Anderson,
1963; personal observations, A. arabicus— Anderson, 1895). Soft ground types are also

312 E.N.ARNOLD

suggested by the extensive pectination of the digits. Members of the A. cantoris group share
the following features: premaxilla with about seven teeth and usually abruptly narrowed
(least in A. cantoris), usually 24 presacral vertebrae in males, 25 in females (less sexual
differentiation in some populations of A. schmidti), fifth sternal rib often intact; hemipenis
and armature usually showing marked asymmetry (not in most A. cantoris), clavulae not
very complex, connectors relatively slender; first supraocular intact or not much divided and
the fourth large or rather fragmented with a group of granules wedged between it and the
third, subocular nearly always separated from the mouth, usually five upper labials anterior
to the centre of the eye, posterior dorsals coarse and carinate, 12-18 ventrals in longest row
across belly, ventrals arranged in fairly straight longitudinal rows, although sometimes
staggered at sides, nearly always four longitudinal rows of scales on fingers (anterior row
sometimes reduced in A. cantoris), pectination on digits strong, upper caudal scales keeled,
young usually with numerous dorsal stripes (not in A. schmidti) that are typically lost in
adults.
In the past it has been usual to treat these four forms as subspecies of A. cantoris. But,

Table 2 Variation in the A. cantoris group

A. cantoris A. blanfordii A. schmidti

A. arabicus

Hemipenis
size

medial lobe

small
unreduced

medial side of armature virtually

unreduced

lateral clavula

flat and
simple

Postorbital and

postfrontal bones fused

Sexual variation in number

of presacral vertebrae yes

Dorsal scales across mid-body 26-36
Dorsolateral tracts of

enlarged scales on no

hind back
Number of ventral scales in

longest row across belly 1 2( 1 4)
Juveniles with dorsal

stripes yes

Adults striped or with rows

of dark spots sometimes

Tail with transverse bands no

Maximum size within
populations
(snout-vent, mm)

large

somewhat
reduced

lobed and
pocketed

separate
yes

30-46

indicated in
some cases

(11)12-14(16)
yes

sometimes
(all animals
from Muscat)

60-75

large

minute or absent

usually absent

lobed and
sometimes
pocketed

separate

not in populations
from United Arab
Emirates

33-51

yes

13-18

in juveniles and
many adults

67-105

large

minute or
absent

absent

very narrow

separate

yes

27-35
no

(12)14-16
yes

in west of
range

no
55-63

RELATIONSHIPS OF ACANTHODACTYLUS 3 1 3

although they have a strong overall resemblance to each other and, so far as is known, are
allopatric, each has a number of distinctive characters that are often more pronounced than
those separating accepted species of Acanthodactylus (see Table 2). Because of this, it seems
more consistent to give them full species status.

A. cantoris is widespread in northwest India and in Pakistan is found in the southeast and
in the Indus drainage whence it reaches east Afghanistan (Kabul River area, CAS 96200-01 ,
120358-60); it also extends westwards along the Pakistan coast at least to Ormara (BM(NH)
1904.12.7.2; Minton, 1966, records A. blanfordii from this locality but his specimens, RSM
1 964.58.2/6, are in fact A. cantoris). There is some geographical variation, for instance in the
Punjab the anterior row of scales on the fingers is incomplete in some animals. This is true of
a female from Cambellpur (BM(NH) 1933.5.16.8) which is also peculiar in having a rather
blunt snout and elongate, strongly overlapping dorsal scales.

A. blanfordii reaches its easternmost limit in the Helmand drainage of south Afghanistan
and the neighbouring border area of Pakistan (BM(NH) 86.9.21.77-80; Mertens, 1969; it is
also probable that the specimens listed by Clark et al, 1969, and Minton, 1966 are A.
blanfordii). A. blanfordii and A. cantoris may be separated by intervening high ground in this
area but it is possible that they meet on the coast for A. blanfordii extends eastwards as far as
Pasni (Mertens, 1969), only about 130 km from the nearest known A. cantoris locality. The
differences in dorsal and gular scale counts on which these two forms were originally
separated do not always hold but they can be distinguished by the fusion of postorbital and
postfrontal bones in A. cantoris and by hemipenial features. A. blanfordii extends into
eastern Iran at least as far as the Bandar Abbas region (Anderson, 1963) and an isolated
population has recently been found by M. D. Gallagher near Muscat, southeast Arabia
(BM(NH) 1973.723-26, 1976. 1462-64, 1977.68-69); here all the adults examined retain at
least traces of dorsal striping.

A. schmidti is widespread in Arabia where it shows substantial regional variation in body
size (Arnold, 1981/7). It also extends into southwest Iran (Anderson, 1974) but without
apparently contacting A blanfordii.

A. arabicus is restricted to the littoral area of southwest Arabia and seems to be separated
from A. schmidti by hilly, not very sandy country occupied by such species as A. boskianus,
A. felicis and A. opheodurus. Although A. arabicus and A. schmidti both have the medial
side of the hemipenis and armature very reduced, they differ in their other apparent
apomorphies (A. arabicus — very narrow clavula; A. schmidti — often very large size,
dorsolateral tracts of enlarged scales on hind back, lack of stripes in juvenile and adult
patterns) and in dorsal scale number. In fact A. arabicus is more similar to A. blanfordii,
especially Muscat specimens, differing mainly in its more slender build, greater hemipenial
asymmetry, narrower clavula and higher number of ventral scales across the belly (usually
14—16 as against 11-13(14) at Muscat). A. arabicus from Aden and its vicinity are
comparatively large and usually retain stripes or spots when adult but animals from futher
east (as far as Gischin ( = Qishn), NMW 11814/1-16) are smaller and often become uniform
in colouring with maturity.

Relationships within the A. cantoris group are not easy to discern with great certainty,
since most of the apomorphies available for judging affinities are rather weak (see p. 324), but
A. blanfordii, A. schmidti and A. arabicus all differ from A. cantoris in their more narrowed
premaxillae, more asymmetrical hemipenes and usually higher number of ventrals, while
lacking its fused postorbital and postfrontal bones and its hemipenial peculiarities (p. 305),
so they may well form a distinct unit with A. blanfordii as the least modified species. Within
it, A. schmidti and A. arabicus share almost total loss of the medial side of the hemipenis and
armature, but there are no other apparent synapomorphies joining them, apart from increase
in ventral scale count. As extreme hemipenial asymmetry has developed a number of times
within Acanthodactylus, its value as an indicator of relationship is quite low. It is possible
that A. schmidti is the sister species of A. blanfordii for the latter occasionally shows
indications of the dorsolateral tracts of enlarged scales on the hind-back that are typical of

314 E.N.ARNOLD

the former and they often share a peculiar lateral clavula shape in which there is a proxi-
mally directed pocket. Moreover, A. schmidti occasionally has a medial clavula exactly like
that of A. blanfordii. Certainly A. arabicus and A. schmidti are more like A. blanfordii than
like each other and may well have been independently derived from a A. blanfordii-\ike
stock.

A. gongrorhynchatus is sympatric with A. schmidti in east and southeast Arabia and shares
many features of the A. cantoris group but it differs in its very slender adult build, convex
pileus, short but abruptly acuminate snout, weakly keeled supratemporal scales that are
fragmented posteriorly, four upper labials anterior to the centre of the eye, an ear hole that is
reduced in size and fine dorsal scaling that sometimes grades into the ventral scales. Recent
observations by Mr W. Ross (personal communication) show that A. gongrorhynchatus lives
on aeolian sand. Its morphology — depressed fingers, strong digital pectination, very pointed
snout and partly occluded ear opening — is appropriate for such a substrate and suggests that
it is more strictly confined to this habitat than A. schmidti which occupies the same general
area. A. gongrorhynchatus may well be paedomorphic in some features which are typical of
juvenile Acanthodactylus, for instance the rounded pileus, short snout and lack of strong
keeling on the supratemporal scales. In fact it has substantial resemblance to immature
specimens of A. arabicus and may well be closely related to this species, especially as their
hemipenes are very similar including the very narrow lateral clavula.

The present situation in Arabia may have arisen by a second stock of the A. cantoris group
invading to exist alongside one already present. It is possible that much of the peninsula was
originally occupied by A. arabicus-\ike populations and that the precursor of A. schmidti
entered the area from the east to become sympatric with them, except in the extreme south-
west littoral region which is isolated by geographical barriers. Here A. arabicus survives but
elsewhere coexistence of two species in soft-sand habitats favoured by the A. cantoris group
would be expected to produce considerable character displacement, the A. arabicus-like
stock giving rise to A. gongrorhynchatus and the invading one to A. schmidti, the two most
divergent species in the assemblage. An analagous situation exists among the nocturnal
ground geckoes of the genus Stenodactylus that occupy soft sand habitats (Arnold, 1980a).
As in Acanthodactylus there is a single species in the southwestern littoral region of Arabia
(S. pulcher) which has a close relative widespread in the peninsula (S. arabicus), where it is
sympatric with another more distantly related species (S. doriae). As with A. gongrorhyn-
chatus, S. arabicus is more strongly adapted to sandy environments and smaller than its
southwestern relative whereas S. doriae, like A. schmidti is relatively large.

A. haasi is known only from the male holotype obtained at Dahran, eastern Saudi Arabia.
In spite of being collected in 1946, no further examples have appeared, even though a great
deal of Acanthodactylus material has been taken in the general area. A. haasi has much in
common with A. gongrorhynchatus and shares a number of synapomorphies with it that
occur nowhere else in the genus; these include very slender habitus, similar lateral clavula
structure and reduced ear opening. It differs in its less acuminate snout and less narrowed
premaxilla, shorter lateral clavula, five upper labials anterior to the centre of the eye, large
and weakly keeled dorsal scales, less pectination on the fingers and numerous keels on the
subdigital lamellae. In most of these features and many others A. haasi resembles members of
the A. cantoris group from which A. gongrorhynchatus is probably derived. This together
with the synapomorphies shared with the latter may indicate that A. haasi and A.
gongrorhynchatus are sister species.

Another possibility, suggested partly by the fact that no further specimens have been
collected, is that A. haasi is a hybrid between A. gongrorhynchatus and one of the other
Acanthodactylus species in eastern Arabia. Assuming that a hybrid would probably be
intermediate in many features, the various candidates can be considered in turn. A. schmidti
is unlikely because its premaxilla is constricted, it has a high number of ventral scales in the
longest row across the belly (13-18 compared with 10-12 in A. gongrorhynchatus and 12 in
A. haasi), pectination on the fingers is extensive, multiple carination on the digits is absent

RELATIONSHIPS OF ACANTHODACTYLUS 3 1 5

(present in A. haasi) and, in east Arabia, it is a far larger animal than A. gongrorhynchatus, so
interspecific copulation is unlikely; size difference would probably also exclude A. boskianus
as well. A. scutellatus has a narrow premaxilla with only five teeth, dorsal scaling is fine and
again there is no multiple carination on the digits. A. opheodurus has this feature in at least
some cases and possesses all the other characteristics to be expected if A. haasi is a hybrid
between it and A. gongrorhynchatus. But the status of A. haasi will probably only be decided
by further collection in the area of the type locality.

A. schreiberi and A. boskianus

A. schreiberi Boulenger, 1878; Cyprus, Lebanon, N. Israel.

A. boskianus (Daudin, 1802): Much of north Africa as far south as N. Nigeria and Eritrea, Arabia but
not the R'ub al Khali, S. Israel, Jordan, Iraq, Syria and adjoining Turkey.

These species are rarely found on very soft sand surfaces but occur on more stable sand and
other harder substrates. A. boskianus is often associated with quite dense, sometimes spiny
vegetation, although it also forages in more open areas (Doumergue, 1901; Flower, 1933;
field labels attached to BM specimens; personal observations in southeast Arabia). Both
species share a relatively high number of primitive features including the following:
premaxilla with about seven teeth and not abruptly narrowed, usually 24 presacral vertebrae
in males and 25 in females; fifth sternal rib often intact, hemipenis more or less symmetrical,
medial side of clavula not strongly reduced; supraoculars more or less intact (first sometimes
divided in A. boskianus), usually four upper labials anterior to centre of eye, typically 10
ventral scales in longest row across belly (12 in many Arabian A. boskianus), ventrals
arranged in straight longitudinal rows, three longitudinal rows of scales on fingers,
pectination on digits not exceptionally strong, upper caudal scales keeled, young with
numerous dorsal stripes that are sometimes retained in modified form by adults. Apparently
apomorphic characters include reduction of the proximal lip of the medial branch of the
hemipenial sulcus, some reduction of medial side of armature, medial clavula pointed with a
^ -shaped cross section, lateral clavula complexly lobed, most medial of the lateral
connectors broad; subocular does not usually reach mouth (exceptions in A. boskianus) and
dorsal scales are often large. The close resemblance of A. schreiberi and A. boskianus
together with the close match of their hemipenes in apomorphic features makes it very
probable that they are sister species.

A. schreiberi has two allopatric populations: A. s. schreiberi on Cyprus and A. schreiberi
syriacus Boettger, 1879 in Lebanon and north Israel, the latter having coarser dorsal scales
with sharper keels. A. boskianus usually differs most obviously from A. schreiberi in
possessing larger dorsal scales. However there is slight overlap in the transverse scale counts
between the hind limbs, but not in Israel where the two species appear to contact each other
without introgression (Duvdevani and Borut, 19746). A. boskianus is the most widely
distributed species of its genus but the range is not continuous in northern Africa where this
lizard is mainy restricted to the periphery of the Saharan desert and to oases and other
fairly mesic areas within it. As the species is relatively uniform in this region, its spread
to these isolated areas may have been quite recent, presumably during one of the episodes in
the Quaternary when conditions in north Africa were less extreme.

A. boskianus has been divided into three subspecies: A. b. boskianus in the Nile delta area
and parts of Sinai; A. b. euphraticus Boulenger, 1919 described from Ramadieh ( = Ramdi,
Iraq) and A. b. asper (Audouin, 1829) which covers almost the whole of the species' range.
This simple, tripartite division is not satisfactory, for some of the supposedly distinctive
features of A. b. euphraticus are not consistent and there is some differentiation within the
populations assigned to A. b. asper. An adequate intraspecific treatment of A. boskianus is
beyond the scope of this paper but variation of some features within the species will be

316 E.N.ARNOLD

briefly described. Over most of north Africa, the number of dorsal scales in a transverse row
at mid-body varies from about 26 to 41, although maxima are less in many areas, the first
supraocular scale is usually intact and the subocular does not reach the mouth in most
individuals. In the Nile delta and north Sinai, populations assigned to A. b. boskianus have
high dorsal scale counts (34-52) and the supraocular scale is divided, but these populations
intergrade with those typical of the rest of north Africa and with similar ones in Israel and
west Jordan. Animals with high dorsal counts (38-48) also occur in northeast Jordan, north
and central Iraq, east Syria and adjoining Turkey. In some cases, such as the types of A. b.
euphraticus, they also have the first supraocular divided and the subocular often meeting the
mouth, but these conditions are absent in many individuals from neighbouring populations.
Arabian animals are rather similar to those widespread in north Africa but are characterized
by low transverse dorsal scale counts at mid-body (usually 18-27 but up to 36 in the south-
western mountains) and a large body size (up to 93 mm from snout to vent against maxima of
about 82 elsewhere; specimens from the western periphery of the peninsula tend to be
smaller). Arabian A. boskianus contrast strongly with those found to the north. In Jordan an
animal from the southeast of the country (El Inab, JUM R505) is of the Arabian type
whereas those from elsewhere are less coarsely scaled (31-37 scales across mid-back) and
relatively small (only up to about 65 mm from snout to vent). Animals of this type occur at
Wadi Rum (JUM R69), only about 130 km from El Inab. Whether the two forms intergrade
and, if so, whether the intergradation is abrupt is not known.

Geographical variation in A. boskianus may well reflect differences in niche across its
range. As stated, this species is often associated with dense vegetation and large dorsal scales
may well be protective where shrubs are rigid and spiny; the fine-scaled populations are in
relatively mesic areas (Nile Delta, Tigris-Euphrates river system) where vegetation would be
expected to be less damaging than in more arid regions. Division of the first supraocular scale
and a subocular that reaches the mouth are also characters typical of more mesic situations
(see p. 307). The distinctive features of lowland Arabian A. boskianus may be related to the
fact that they coexist here with A. opheodurus, a small form originally confused with A.
boskianus that occupies similar substrates and occurs in strict sympatry with it, at least in
some areas (Arnold, 19806). The presence of A. opheodurus might have produced displace-
ment or restriction of the niche available to A. boskianus with consequent morphological
change (Arnold, 19816). Thus, increase in body size may allow adult A. boskianus to take
larger prey, reducing competition for small food items; very large scale size could indicate
that this species spends a higher proportion of time in vegetation than elsewhere. It is
perhaps significant that in extreme southwest Arabia, where no A. opheodurus are known, A.
boskianus is smaller with higher dorsal scale counts than elsewhere in the peninsula.

In spite of the considerable variation encountered in A. boskianus, as presently under-
stood, there is as yet no firm evidence that it consists of more than one species. However, A.
schreiberi may well have originated as an isolate of A. boskianus.

The A. grand is complex

A. grandis Boulenger, 1909 complex (including A. fraseri Boulenger, 1918c): Syria, E. Lebanon,
Jordan, NW. Arabia, Iraq, SW. Iran (Khuzistan and Pars provinces — Anderson, 1974).

Nothing certain is known about the ecology of these lizards but the restricted pectination on
the digits suggests that they are not usually found on very soft sand surfaces; however there is
some variation in this feature between populations which may indicate that they occupy a
variety of ground types. The members of the A. grandis complex share many features with A.
schreiberi and A. boskianus, especially the former, the most significant differences being
that, in the A. grandis complex, the ventrals are tessellated and the number in the longest
row across the belly is higher (14-18), there are four longitudinal series of scales running
along the fingers and the hemipenis, although generally very similar often differs slightly in
the pattern of lobing on the upper surface of the lateral clavula (p. 306); also, five upper
labial scales are more frequently present anterior to the centre of the eye.

RELATIONSHIPS OF ACANTHODACTYLUS
Table 3 A. grandis complex: variation between samples

317

Locality n

Maximum
snout-vent Dorsal scales
length of in transverse
available row at
adults mid-body

Strength of
keeling on
dorsal scales
(0-none,
4-strong)

Ventral
scales in
longest row
across belly

Projections on
free edges of
sub-digital
lamellae

JORDAN and SYRIA

(BM, MCZ56647,

including types of

A. grandis) 6

cT!03 56-64

16-18

several

IRAQ (localties

listed from

northwest to

southeast)

Hatrah, Ninevah

Prov. (INHM) 2

rf70 47,49

several

Rawa Desert

(BM) 2

several

Jabal Hamrin

(INHM) 1

962 49

several

Between Baghdad

and Falluja

(BM) 4

43-50

several

Al Uzaym, Dijla

Prov. (INHM) 1

c?90 53

one

Shthath, Kerbala

(INHM) 1

one

25 km S. of

Najaf

(INHM) 1

d76 50

one

Nassiryah (BM) 1

rf78 49

one

Zubeya( = Az

Zubayr, BM,

types of A.

fraseri)

rf73 48,50

one

SW.IRAN

(USNM 13500-01) 2

c?63 42,44

14-16

one

A. grandis was originally described from the Damascus area of Syria while the only other
nominal species assignable to the complex, A. fraseri, is based on material from Zobeya,
Shariba ( = Shu'aiba, northeast of Basra) far to the east in southeastern Iraq. Material
collected subsequently in the intervening areas shows a variety of conditions intermediate
between the named forms but the pattern of variation appears to be irregular and sometimes
animals from adjacent localities show considerable differences in such features as adult size,
strength of keeling on the dorsal scales, and pattern (summarized in Table 3). In general,
members of the eastern populations tend to be smaller than western animals with fewer,
more strongly keeled dorsal scales and single points on each subdigital lamella.

It is possible that the A. grandis complex is best regarded as a single species but available
samples are too small and scattered to be certain about this. The irregular variation of
populations intermediate between typical A. grandis and A. fraseri may reflect the geography
of Mesopotamia, for here the comparatively arid country favoured by Acanthodactylus is
divided up by the Tigris and Euphrates rivers and their tributaries which flood seasonally, so
populations may be substantially discontinuous. Other Acanthodactylus species, especially
A. boskianus, also show considerable variation in this area.

318 E.N.ARNOLD

The A. tristrami group

A. (/.) tristrami (Giinther, 1864): Lebanon, SW. Syria, NW. Jordan.

A. (/.) orientalis Angel, 1936: E. Syria, W. and central Iraq.

A. robustus Werner, 1929: S. Syria, SW. Iraq, Jordan and N. Arabia.

The weak digital pectination in these forms suggests that they are found on fairly hard
substrates. A. (t.) tristrami seems to be confined to steppe-type habitats on the edge of the
Anti-Lebanon range. A. (t.) orientalis may also be restricted to relatively mesic habitats since
most records are from localities on or near the Tigris-Euphrates river system (Angel, 1936;
Schmidt, 1939; Haas and Werner, 1969), although Angel also records it from Palmyra. A.
robustus, on the other hand seems to occupy more desertic regions; Riney (1953) gives brief
ecological notes that refer to this species, although they are attributed to A. (t.) orientalis.

Typical A. tristrami has many features in common with A. schreiberi (p. 3 1 5) but there
are a number of differences: there are more presacral vertebrae, with about 25 in males and 26
or 27 in females, the proximal lip of the medial branch of the hemipenial sulcus is not
reduced, the lateral clavula is complex but not lobed and is very slightly bifurcate at its tip,
the first and fourth supraoculars are fragmented, the subocular reaches the mouth, the dorsal
and upper caudal scales lack keels and the tail is short. Of these features, fragmentation of the
supraoculars, unkeeled upper caudals, short tail, clavula shape, and perhaps vertebral
number may be regarded as apomorphies. Nearly all occur in other populations of the A.
tristrami group and unkeeled upper caudals and the short tail are confined to it.

Two other subspecies assigned to A. tristrami have been named, A. t. orientalis from
eastern Syria and A. t. iracensis, Schmidt, 1939, described from Haditha on the Euphrates in
west Iraq. The latter is said to have a lower mid-body dorsal scale count (45-46 against
48-56) and a weaker dorsal pattern than A. t. orientalis but other material from the same area
(Haas & Werner, 1969) and from Najaf, further down the Euphrates (INHM, with 51 dorsal
scales at mid-body and a bold pattern) suggest that this distinction is illusory. A. t. iracensis is
therefore referred to the synonymy of orientalis. As understood here, this form is
distinguished from typical tristrami by its smaller size (up to 63 mm from snout to vent
instead of up to 92 mm) and fewer dorsal scales (43-56 against 54-65). The hemipenes are
also distinctive, orientalis having the medial lobe and medial side of the armature very
reduced. These differences suggest that tristrami and orientalis might be better regarded as
full species but more information is needed before this can be confirmed.

A. robustus shares most of the distinctive features of A. (t.) tristrami but the lateral clavula
is relatively simple, the snout is shorter and more pointed, the subocular frequently
separated from the mouth, there are often 12 instead of 10 ventrals in the longest row across
the belly and there may be a rudimentary fourth longitudinal row of scales on the fingers.

A. ery thrums group

A. erythrurus (Schinz, 1833): Spain, Portugal, Morocco, N. Algeria.

A. savignyi(Audou\n, 1829): N. Algeria, N. Tunisia.

A. boueti Chabanaud, 1 9 1 7: N. Dahomey, N. Ghana.

A. guineensis (Boulenger, 1887a): Ghana, Nigeria, Niger and Cameroon.

These species are typical of relatively mesic areas and usually have weak digital pectination.
They are similar to A. (t.) tristrami in many features but all lack the short tail and unkeeled
upper caudal scales of this form and also frequently have an azygos shield between the
prefrontal scales.

In A. erythrurus and A. savignyi the lateral clavula of the hemipenis is deeply bifurcate at
its tip, the frontonasal scale is quite often divided and the subocular may be separated from
the lip.

A. erythrurus has three widespread forms: A. e. erythrurus in Spain and Portugal A. e.
lineomaculatus Dumeril & Bibron, 1839 in lowland western Morocco and A. e. bellii Gray,

RELATIONSHIPS OF ACANTHODACTYLUS 3 1 9

1845 in the adjoining higher country and in north Algeria. Each of these is well denned on
external features and A. e. bellii is further distinguished by its usually simple lateral clavula.
Two other subspecies are sometimes recognized: A. e. mauritanicus, Doumergue, 1901 of
extreme northern Algeria resembles A. e. bellii in most features including its lateral clavula
and differs only in its more obviously keeled dorsals; A. e. atlanticus Boulenger, 1918# has a
restricted distribution in north Morocco between the ranges of A. e. bellii and A. e.
lineomaculatus and may be an intermediate between them. A. savignyi bland Doumergue,
1 90 1 of north Tunisia is very similar to A. e. lineomaculatus but A. s. savignyi which coexists
with A. erythrurus in north Algeria is more distinctive. It has a clearly pointed snout and a
better developed pectination on the digits than is usual in its close relatives which may be
related to its occupying more sandy habitats (Doumergue, 1901). It is possible that the
differences between the two subspecies of A. savignyi are a result of character displacement
(Arnold, 198 16).

A. boueti and A. guineensis are generally like the above but the frontonasal is undivided
and the subocular scale is never separated from the lip. Each species has a number of
distinctive features. In A. boueti there are nine premaxillary teeth, the hemipenis is very
small, the second supraocular scale is broken up and the parietal scales are partly
fragmented. A. guineensis has the medial side of the hemipenis and armature absent and a
peculiar arrangement of nasal scales (p. 296), a feature that occurs rarely also in A.
erythrurus.

The A. pardalis group

A. p. pardalis (Lichtenstein, 1823): Cyrenaica, north Egypt, Israel.

A. p. bedriagai Lataste, 1881: High plateaux of north Algeria (provinces of Oran, Algiers and

Constantine); closely related populations in west Morrocco and west Tunisia.
A. maculatus (Gray, 1838): northeast Morocco, north Algeria, Tunisia, Tripolitania.
A. spinicauda Doumergue, 1901: Arba Tahtani and El Abiodh Sidi Sheikh, northwest Algeria.

Members of the A. pardalis group are largely confined to relatively hard compact substrates
such as clayey-sandy soils, clay, loess and salt flats (Blanc, 1980; Gauthier, 1967; Mosauer,
1 934; data on labels attached to BM(NH) specimens).

They all agree in the following characters: premaxilla with about seven teeth, not
narrowed and separated from the maxillae by a constriction, presacral vertebrae usually
24-26 in males and 25-26 in females, fifth sternal rib often interrupted; hemipenis and
armature asymmetrical, often markedly so, lateral clavula often bifurcate at tip, lateral
connectors often thickened; first supraocular intact or not very much divided and the fourth
fragmented, subocular separated from mouth, four or five upper labials anterior to centre of
eye, dorsals small and often more or less smooth, 12 or more ventrals in longest row across
belly, ventrals arranged in fairly straight longitudinal rows, three longitudinal rows of scales
on fingers, pectination on digits relatively weak although somewhat variable, young with
numerous dorsal stripes.

Boulenger (1918a, 1921) treated the A. pardalis group as a single species within which he
recognized five varieties: pardalis (his forma typica), bedriagai, maculatus, latastii
Boulenger, 1918a and spinicauda. Pasteur & Bons (I960) regarded spinicauda as a distinct
species but felt that the other varieties were no more than individual variations and placed
them in the synonymy of the monotypic species A. pardalis. In fact, the introduction of
osteological and hemipenial data helps to confirm the validity of the majority of Boulenger's
divisions and it appears that at least five entities within the A. pardalis group can be
recognized (see Table 4 & Fig. 7), A. maculatus, as understood here, includes Boulenger's
var. latastii. This author restricted maculatus to often relatively small-bodied populations in
which the posterior dorsal scales are frequently keeled and some individuals have light
stripes or rows of light spots. These are distributed along the coastal areas of Tripolitania and

320 E. N. ARNOLD

Table 4 Variation within the Acanthodactylus pardalis group

A. p. A. p.

pardalis bedriagai

Un-named
west Moroccan
population

A. A.

maculatus spinicauda

Hemipenis lacks medial

lobe and medial section of

armature
Usual number of presacral

vertebrae: males
females
Approximate number of animals

in which 5th sternal rib

is interrupted
Number of ventral scales in

longest transverse row
Longitudinal rows of ventral

scales
Keeling on dorsal scales

often quite strong
Enlarged, tubercular scales

on sides of tail base

24/25
25(26)

26
26

20/24 7/14

26
26

4/9

24
25

24
26

12(14) 14(12,16) 12

27-34 31-36

30-34

48/62 7/10

12(14) 12

27-33 27-33

'excluding population from Tamesmida, see below.

Tunisia and in northeast Algeria. The name latastii was applied to inland populations lying
mainly to the south in which body size is sometimes greater, dorsal scales are usually more or
less smooth, the dorsal pattern tends to lack light stripes or spots and the snout is more
pointed. However, there is considerable variation and many intermediates occur, so it seems
best to regard these populations as a single unit. The geographical differences within this
may reflect change in vegetation and substrate conditions; the pattern of maculatus-type
animals is more likely to be cryptic where vegetation is relatively dense whilst that typical of
latastii is probably cryptic in more open areas.

The relationships between the forms described in Table 4 are not entirely clear, but it is
certain that they cannot all be assigned to a single species. Although no areas of certain
sympatry are known, bedriagai, the form of the high plateaux of north Algeria, approaches
the more southern maculatus near Biskra (bedriagai — Aures Mountains north of Biskra,
BM(NH) 91.5.4.70-72; maculatus— near Biskra, BM(NH) 1907.4.6.10-25, BM(NH)
1920.1.20.791, BM(NH) 1969.2121-23). The two localities are probably within 100 km of
each other but the forms retain their differences in hemipenial structure, usual number of
presacral vertebrae and of ventral scales in the longest row across the belly, and in pattern. It
seems likely therefore that bedriagai and maculatus are distinct species, especially as the
hemipenial differences between them could act as an isolating mechanism.

The un-named west Moroccan population (north of Agadir, BM(NH) 1970.246^7; 20 km
north of Tiznit, BM 1970.248; 30km southwest of Goulmime, BM(NH) 1970.249-50) is
generally similar to bedriagai and is probably conspecific with it but differs in the following
features: snout often more pointed, posterior dorsal scales more pointed and keeled, ventrals
in longest row across belly often 12 (not 14), upper labials anterior to centre of eye often four
(frequently five in bedriagai), range of dorsal patterns somewhat different. It is possible that
this population also contacts A. maculatus although evidence is lacking.

Another A. bedriagai-\ike population occurs at Tamesmida (33.05N 8.23E) in western
Tunisia (BM(NH) 1920.1.20.3018, discussed by Boulenger, 1921, p. 67). The two male
specimens available resemble this form very closely in osteological features and externals
but the hemipenis is single-lobed and the median side of the armature is lacking. Close by at

RELATIONSHIPS OF ACANTHODACTYLUS

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322 E. N. ARNOLD

Furryanah (34.57N 8.35E), A. maculatus occurs (BM(NH) 1920.1. 20.30 18e) but, as the
Tamesmida specimens are not like this form in other respects, a hybrid origin for them seems
unlikely. Possibly they represent an isolate of the A. bedriagai stock that has undergone
hemipenial modification in response to some previous threat of introgression, as seems to
have happened several times in Acanthodactylus (p. 304). Tamesmida is on the edge of the
eastern extension of the high ground on which A. bedriagai is found.

The form spinicauda is known only from Arba Tahtani ( = Arbaouat, 33.05N 00.35E) and
nearby El Abior Sidi Sheikh ( = E1 Abiodh Sidi Cheikh, 32.53N 00.34E), oases at the
southern foot of the Saharan Atlas in northwest Algeria. In general form, hemipenial
structure and pattern, it resembles A. maculatus populations in the region (Mecheria and
Laghouat) but differs in having the lateral scales at the base of the tail greatly enlarged,
especially in males, with their keels produced to form tubercles, this condition occurring in
no other lacertid. The hind legs are also rather longer than in nearby A. maculatus
populations, although this is partly due to the fact that relative hind-leg length decreases
with size and spinicauda is quite small; three females radiographed all have 26 presacral
vertebrae instead of the 25 usual in A. maculatus. The two forms do not appear to be
sympatric, so a direct test of the species status of spinicauda is not possible. It is certainly
very like neighbouring A. maculatus but the three distinctive features, especially the unique
tail structure, suggest it may be best to regard it as a full species, at least for the present. In the
south of its range, maculatus appears to have a disjunct distribution, occurring mainly
around oases such as Ouargla, Ghardia and Leghouat. Presumably its range was once more
continuous but has become fragmented since the climate of the area has become more
extreme. It is probable that A. spinicauda originated from such an oasis isolate.

Typical A. pardalis show some variation, for instance animals from the Jebel el Akhdar
region of Cyrenaica appear to be smaller than samples to the south and east. Also, although
Egyptian animals usually have 24 presacral vertebrae in males and 25 in females, in
Cyrenaica 25 is common in males and females sometimes have 26. While there is evidence
that bedriagai and maculatus are specifically distinct, it is less clear how they are related to
typical A. pardalis. This is partly because neither is known to contact this form, there being a
gap in the known range of the A. pardalis group as a whole south of the Gulf of Sirte, Libya,
although whether this is real or a collecting artifact is uncertain. Typical A. pardalis
resembles bedriagai in hemipenial structure but differs in usual number of presacral
vertebrae and ventral scales in the longest row across the belly (although the bedriagai-\ike
population in west Morocco matches pardalis in this last characteristic). On the other hand,
A. pardalis resembles maculatus in these features and the nearest populations of each form
are quite similar, although coastal maculatus west of the Gulf of Sirte are smaller and have
more strongly keeled dorsal scales than the closest pardalis. However, these two forms differ
radically in hemipenial structure which, coupled with size-difference in this area might well
preclude interbreeding. This being so, it seems reasonable to regard maculatus as specifically
distinct from pardalis, although it cannot be ruled out that connecting populations may yet
be found in north Libya with intermediate hemipenes. Typical bedriagai and the similar
west Moroccan population are tentatively regarded as conspecific with pardalis as they are
hemipenially similar and the differences between them are mainly in features showing
substantial variation within each population. On hemipenial evidence, the Tamesmida
population may be specifically distinct from A. bedriagai but it seems safest to leave its status
undecided until more is known about it.

The 1. scutellatus group

A. scutellatus (Audouin, 1829): North Africa south to Senegal, Mauretania, Mali, Niger, N. Chad and

N. Sudan; S. Israel, N. Arabia, S. and central Iraq.
A. longipes Boulenger, 1918a: North Africa including parts of S. Morocco, Algeria, Libya, Mauretania,

Mali, Niger and Chad.

RELATIONSHIPS OF ACANTHODACTYLUS 323

A. aureus Gunther, 1903; Coasatal areas of NW. Africa from S. Morocco to Mauretania; also some
neighbouring inland areas.

The A. scutellatus group is largely associated with soft-sand habitats (Anderson, 1898;
Doumergue, 1901; Flower, 1933; Mosauer, 1934; Gauthier, 1967; Blanc, 1980; field labels
on BM(NH) material); this is also suggested by the extensive pectination usually present on
the toes. However occasional populations are found on harder substrates (Scortecci, 1946).
In north Africa the group occupies many desert areas and, unlike A. boskianus in this region,
is not largely confined to relatively mesic enclaves. A. scutellatus and its relatives have few
features plesiomorphic within Acanthodactylus but many apomorphic ones including the
following: premaxilla often with only five teeth and abruptly narrowed, usual number of
presacral vertebrae 23 or 24 with very little sexual variation, fifth sternal rib interrupted in a
high proportion of individuals; medial lobe of hemipenis, medial branch of sulcus and
medial side of armature absent or greatly reduced, clavula with a ID -shaped cross section;
subocular scale separated from mouth, five or six upper labial scales anterior to centre of eye
(four in A. aureus), (10)12-18 ventral scales in longest row across belly; ventrals tessellated,
four longitudinal rows of scales on fingers, pectination on digits usually strong; young often
uniform above.

The populations that constitute the A. scutellatus group show great variation in some
features: maximum adult size ranges from about 50 mm from snout to vent to nearly 80 mm,
dorsal scales may be coarse and keeled or fine and smooth, transverse counts at mid-body
ranging from 36 to 100, number and degree of tessellation of ventral scales varies as does
amount of pectination on digits and dorsal pattern ranges from stripes or rows of spots to
reticulation or uniformity. From analogy with other species in the genus, keeled dorsal
scales, low scale counts, reduced ventral tessellation, limited pectination and striped patterns
are all likely to be associated with habitats that have harder substrates and more extensive
vegetation, whereas contrasting conditions may be typical of soft, open sand.

Although the A. scutellatus group is easily defined, recognition of taxa within it is difficult.
Boulenger, (19180, 1921) treated it as a single species with six varieties. Bons & Girot (1962)
pointed out that, as some of these were sympatric, they could not be regarded as mere
subspecies and suggested the following arrangement for Boulenger's taxa; they also included
a form named by Haas (1957) and another described by themselves.

A. scutellatus scutellatus (Audouin, 1829): Egypt, Israel, Sudan.

A. scutellatus hardyi Haas, 1957: Arabia, S. Iraq.

A. scutellatus audouini Boulenger, 1918#: S. Egypt, Libya, S. Tunisia, S. Algeria.

A. longipes longipes Boulenger, 1918#: S. Libya, Algerian Sahara.

A. longipes panousei Bons & Girot, 1962: SE. Morocco.

A. inornatus inornatus (Gray, 1838): N. Libya, Tunisia, N. Algeria, S. Morocco.

A. inornatus aureus Gunther, 1903: Atlantic coast from S. Morocco to Port Etienne.

A. dumerilii (Milne-Edwardes, 1829): Senegal, Mauretania, Niger.

But this system too presents problems for there is no real evidence that A. scutellatus, A.
inornatus and A. dumerilii act as good species, nor is it clear that A. i. inornatus and A. i.
aureus are conspecific. Difficulties in the interpretation of the A. scutellatus group arise
partly because intrapopulational variation is great and there are large areas in its huge range
where material is unavailable. Problems also stem from the geographical structure of the
group. The soft-sand habitats favoured by these lizards are by no means continuous and
consist of a series of isolates and semi-isolates which have almost certainly had a complicated
history of contraction and expansion, and contact and isolation (see, for instance Sarnthein,
1 978). The lizard populations associated with these different, partly discrete habitat units are
likely to have been subjected to differing selective regimes and even neighbouring
populations may show differences. However, although the A. scutellatus group exhibits great

324 E. N. ARNOLD

variation, it is mainly in a few characters that are likely to be ecologically correlated and it
seems possible that similar morphotypes may have developed independently in some cases.

Sometimes, populations may have evolved differences while isolated that enable them to
act as good species if contact is restored. Such areas of sympatry or parapatry would provide
the best evidence of speciation within the A. scutellatus group but, in the stringent environ-
ments inhabited by these lizards, the niche space they usually occupy may often be able to
support only one species, so that areas of extensive sympatry may be uncommon and regions
of contact will frequently be very restricted. Given the poor sampling available, places where
two species occur together will not be very easy to find. Nevertheless they do exist and there
are others where quite different populations approach each other very closely. On the basis
of such localities, the A. scutellatus group is best divided into three species A. scutellatus,
A. longpipes and A. aureus.

A. scutellatus

As understood here, this widespread species consists of populations in which there are
typically less than 70 dorsal scales in a transverse row at mid-body and not usually more than
1 4 ventral scales in the longest row across the belly (exceptions to both frequent in Egypt and
neighbouring areas), five or six upper labial scales anterior to the centre of the eye,
premaxilla typically with five teeth, most usually 24 presacral vertebrae and dorsal
coloration highly variable. Variation is summarized in Table 5. The name A. scutellatus was
originally applied to the often large, frequently reticulated, fine scaled populations of
northern Egypt. The var. audouini of Boulenger is said to differ in usually having spots or
vermiculations and in its coarser, keeled dorsal scales but individuals assignable to these two
forms occur in the region of Wadi Haifa, Sudan, alongside intermediates and animals from
Kufra cannot be convincingly assigned to one form or the other. Other examples attributed
by Boulenger to var. audouini occur on the coast of Tripolitania but extensive material now
in the British Museum (Natural History) shows that these intergrade with other samples
assignable to the small var. inornatus. The snout-length difference between these forms
mentioned by Boulenger is very difficult to demonstrate and is complicated by allometric
changes. It seems very improbable, on present evidence, that two species are represented by
these samples.

Animals from Mauretania and Senegal were assigned by Boulenger to var. dumerilii,
regarded as a full species by Bons and Girot. This form is characterized by usually small size,
coarse dorsal scales, low ventral number and sometimes striped dorsal patterns. But, if
samples are compared, there is a gradual change from south to north the numbers of dorsals
and ventrals increasing and striping disappearing (Table 5, localities N-J). The most
northern animals are extremely similar to the next available samples in northern Algeria and
there are certainly no differences that would suggest they are not conspecific.

In summary, the forms scutellatus, audouini, inornatus and dumerilii are not discrete and,
on present evidence, cannot be separated at the species level. The pattern of geographical
variation in A. scutellatus seems too complex to assign subspecies names in any consistent
way, at least at present.

A. longipes

This species can be distinguished from sympatric or parapatric A. scutellatus by its higher
mid-dorsal transverse scale count (usually over 70 and always over 65), typically greater
number of ventral scales in the longest row across the belly (often more than 14) and
frequently lower presacral vertebral count (usually 23); the dorsum is typically very pale,
either plain or with a reticulation on the flanks. These differences, together with its usually
greater pectination on the toes, suggest that it occupies softer, more open sand than A.
scutellatus, where they occur together. A number of contact or approach areas are known.
In northern Algeria, there may be considerable geographical overlap but in Mauretania only
a narrow abutment seems to be present with A. scutellatus in the west and A. longipes in the

RELATIONSHIPS OF ACANTHODACTYLUS

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east. In south Libya sympatry may be quite extensive, as indicated by Scortecci, 1946 (his
group A is apparently A. scutellatus and group B is A. longipes). This author's observations
give some support to the ecological separation between the two species suggested above.

Localities for A. longipes are very scattered and, given the disjunct nature of the sort of
habitat that it occupies, this species may consist of several quite isolated populations.

A. aureus

The populations found along the Atlantic coast of northwest Africa are all rather similar and
in many respects resemble neighbouring A. scutellatus (referred by Bons and Girot to A. i.
inornatus). They differ most obviously from this species in having only four upper labial
scales anterior to the centre of the eye, seven teeth in the premaxilla and the snout is often
more acuminate. Such animals, typical of A. aureus, may occur some way from the coast
(e.g. at Uedi Taamia, 26.0 IN 13.12W; EBD 2450) but at present they are not known to
contact A. scutellatus. However, at two localities in Mauretania, the latter occurs alongside
another form that may well be conspecific with A. aureus. If so this provides some evidence
that the latter is a good species. The animals concerned are from Fort Gouraud (cfcf,
BM(NH) 1982.292-93) and Atar (9, BM(NH) 1982.294) and are compared with sympatric
A. scutellatus in Table 7. They are very similar to typical A. aureus in most features and it
seems likely that they are referrable to this species.

The inter-relationships of the three species that make up the A. scutellatus group are
unclear. A priori, A. aureus might be considered the most primitive, often having seven
premaxillary teeth and four upper labials anterior to the centre of the eye. But, if the
Mauretanian specimens with five premaxillary teeth are assignable to A. aureus, this
apomorphic feature cannot be used to unite A. scutellatus and A. longipes as sister species.
Also, the presence of four, instead of five or six upper labials, may be secondary, for other
species with acuminate snouts (A. gongrorhynchatus, A. masirae] have lower labial scale
counts than expected from their phylogenetic relationships judged by other features.

Table 7 A. aureus: comparison of samples with neighbouring A. scutellatus

Fort Gouraud, Atar Coastal area

scutellatus aureus aureus

Upper labial scales anterior to

centre of eye 5 or 6 4 4

Dorsal scales across mid-body 45-56 38-46 41-60

Lower temporal scales large, often large, usually small,

keeled smooth smooth

Enlarged gular scales bordering

4th and 5th chin shields frequent none rare

Usual number of rows of granules

beneath centre of collar 2 or 3 0 0 or 1

Usual number of premaxillary

teeth 5 57

Pattern of males Fine spots or coarse spots coarse spots or

reticulation vermiculation

RELATIONSHIPS OF ACANTHODACTYLUS 329

The A. opheodurus group

A. opheodurus Arnold, 19806: Arabia (but not apparently the southern desert or northern Oman),

S. Israel, Jordan, parts of Iraq.

A.felicis Arnold, 19806: S. Arabia (Republic of South Yemen and Dhofar, S. Oman)
A. masirae Arnold, 19806: S. Oman.

This assemblage consists of three small species, all wholly or largely confined to Arabia. All
have only recently been described for, although A. opheodurus and A. felicis have been
present in museum collections for some time, they have been confused with A. boskianus.
These lizards appear to be associated with relatively hard substrates and have restricted
pectination on the digits.

The group possesses a high proportion of plesiomorphic features: premaxilla with about
seven teeth and not abruptly narrowed (except in A. masirae), usually 24 presacral vertebrae
in males and 25 in females, fifth sternal rib usually intact; lateral clavula simple, hemipenial
connectors unthickened; first supraocular more or less intact, typically four upper labial
scales anterior to the centre of the eye, eight or ten ventral scales in longest row across belly,
ventrals arranged in straight longitudinal rows, three longitudinal rows of scales around
fingers (a fourth row in A. masirae), pectination on digits not strong, upper caudal scales
keeled, young striped dorsally, the stripes sometimes persisting in adults. However the
hemipenis is highly modified in the A. opheodurus group, the medial lobe and medial side of
the armature being greatly reduced, the fourth supraocular scale is at least partly broken up
and the subocular scale is often separated from the mouth (not in A. masirae) and the
number of stripes in the juvenile pattern shows some reduction. Dorsal scaling is relatively
coarse, there being 25-42 scales in a transverse row across the mid-body.

The three species are grouped together largely on the grounds of overall similarity.

Inter-relationship of the species of Acanthodactylus

The approach used for estimating the phylogeny of the species of Acanthodactylus is briefly
discussed on p. 293. Probably derived character states shared by two or more species
(provisional synapomorphies) are listed in Table 8 and their distribution shown in Table 9.
Polarity, that is which state of a character is primitive and which state or states derived, has
been decided largely by outgroup comparison, using the rest of the Lacertidae as the
outgroup. Some assessment of the relative reliability of characters as indicators of relation-
ship (character weighting) was attempted employing the indicators mentioned by Arnold
(198 la). No features scored very well on this basis and most scored quite badly but among
the better ones were the following (numbers refer to Tables 8 & 9, and Fig. 9): premaxillary
teeth reduced to five (1); hemipenial features not thought to be connected directly with the
development of physical isolating mechanisms against interbreeding discussed on p. 304 (9,
1 1-1 7); reduction in size of the ear opening (24); no keeling on proximal dorsal caudal scales
(30). These features are consequently given some precedence in situations where the
evidence of different derived character states conflicts. Because many features are poly-
morphic, with both the primitive and a derived state occurring together in the same species,
Le Quesne's (1969) method for determining compatible characters could not be used. As well
as joint possession of derived character states, strong overall resemblance is also taken as
prima facie evidence of close relationship. Using these indicators, a provisional partial
phylogeny of Acanthodactylus was constructed and is shown in Fig. 9.

The relationships of the A. cantoris group, A. gongrorhynchatus and A. haasi are discussed
on p. 3 1 1 . By and large, the hypothesis of their relationships shown in Fig. 9 involves a
pattern of shared apomorphies that does not include much homoplasy. As stated, the main
conflict involves the position of A. schmidti: is it more closely related to A. arabicus or to A.
blanfordiil The former relationship is supported by total loss of the medial side of the
hemipenis and armature (8d, lOc) and some increase in the number of ventral scales (26b),

330 E. N. ARNOLD

Table 8 Probable derived character states shared by two or more species of Acanthodactylus. Where
features appear to constitute a transformation series, they are listed in their supposed order of origin
and denoted by a consecutive letter thus: a, b, c, d.

1 . Premaxilla narrowed: a. somewhat; b. distinctly.

2. Premaxillary teeth reduced to five.

3. Presacral vertebrae 23 or 24 in females.

4. Presacral vertebrae 26 or 27 in females.

5. On average, females have less than one more presacral vertebra than males: a. 0-66-0-84 more
vertebrae; b. 0-07-0-33 more vertebrae.

6. Fifth sternal rib interrupted in over 50% of individuals.

7. Hemipenis small.

8. Medial lobe of hemipenis reduced: a. somewhat reduced; b. more strongly reduced; c. very small;
d. minute or absent.

9. Proximal lip of medial branch of hemipenial sulcus reduced to a fold in symmetrical hemipenes.

10. Medial side of armature reduced: a. somewhat reduced; b. more strongly reduced; c. reduced to a
thread or absent.

1 1 . Medial clavula narrow and pointed with a ^ -shaped cross section.

12. Lateral clavula with a proximally directed pocket.

13. Lateral clavula very narrow.

14. Lateral clavula complexly structured with multiple lobes below.

1 5. Lateral clavula complexly structured and divided at tip.

1 6. Lateral clavula folded with D-shaped cross section.

1 7. Most medial connector on lateral side of hemipenis thickened.

1 8. Nostril separated from first upper labial scale by a subnasal.

19. Frontonasal scale longitudinally divided.

20. One or two azygos scales present between the prefrontal scales.

2 1 . Supraocular scales not all intact: a. an area of granules wedged between the third and fourth
supraoculars and the latter sometimes divided; b. first supraocular divided into two or three, fourth
supraocular very fragmented; c. first and fourth supraoculars very fragmented; d. first, second and
fourth supraoculars very fragmented.

22. Subocular scale usually separated from mouth.

23. Upper labial scales anterior to centre of eye more than four.

24. Ear opening reduced in size.

25. Dorsolateral tracts of enlarged scales on posterior body.

26. Maximum number of ventral scales in a transverse row: a. 12; b. 14 or more.

27. Ventral scales tessellated: a. at sides only; b. generally.

28. Ventral scales grade into dorsals: a. to a small extent; b. more generally.

29. Four longitudinal rows of scales on the fingers: a. anterior row irregular; b. anterior row regular
and continuous.

30. No keeling on proximal dorsal caudal scales.

3 1 . Tail less than 1-5 times snout-vent distance.

32. Occipital stripes fuse to form a mid-dorsal band (often not visible in adults): a. fusion does not
extend to occiput; b. fusion extends to occiput.

33. Young without pattern of light and dark stripes.

34. Reddish-brown spots present in pattern that do not fade in alcohol.

35. Two rows of large ocellar markings along back.

while affinity to A. blanfordii is suggested by similarity in lateral clavula structure (12) and
the presence of dorsolateral tracts of enlarged scales (25). The former characters appear
weaker indicators of relationship, especially as they have developed several times in the
Lacertidae, while characters 12 and 25 are known nowhere else. A. schmidti is consequently
regarded as the sister species of A. blanfordii. Whether A. haasi is the sister species of A.
gongrorhynchatus, which is suggested by its slender habitus, reduced ear opening (24) and
some features of the lateral clavula (p. 306), or a hybrid between this species and another
such as A. opheodurus, is discussed elsewhere (p. 314).

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333

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Fig. 9 Tentative hypothesis of the relationships of the species of Acanthodactylus. Figures refer to
derived characters listed in Tables 8 and 9. Lines above species names join forms that have a
very close overall resemblance, vindicates alternative position for the A. scutellatus group (A.
aureus, A. scutellatus and A. longipes).

A number of Acanthodactylus species share a distinctive hemipenial structure which
incorporates two derived features not found elsewhere: the medial clavula is narrow and
pointed with a ^ -shaped cross section (1 1) and the most medial connector on the lateral side
is often thickened (17); in addition there is moderate asymmetry of the armature (lOa). This
pattern occurs in A. boskianus, A. schreiberi, the A. grandis complex, A. (t.) tristrami, A. (t.)
orientalis, A. robustus, A. erythrurus, A. savignyi, A. boueti and A. pardalis. It seems
probable that these forms constitute a monophyletic group in Ashlock's (1974) sense within
Acanthodactylus. Among them A. boskianus, A. schreiberi and the A. grandis complex all
have a reduced proximal lip to the medial branch of the hemipenial sulcus (9) and a lateral
clavula that is complexly lobed (14). Within this trio, A. boskianus and A. schreiberi may
well be sister species, for some populations are extremely similar. A. grandis shows conflict
of evidence as to its relationships. It has some similarity in derived features to members of the
A. cantoris group, viz. high number of ventral scales (26) which are tessellated (27b) and four
longitudinal rows of scales along the fingers (29b). However, weighting criteria (especially
frequent occurrence in groups not closely related to Acanthodactylus} suggest these features
are relatively weak indicators of relationship, whereas it has been argued (p. 329) that most of
the conflicting hemipenial features (9, 11, 14, 17) that ally the A. grandis complex to A.
boskianus and A. schreiberi are likely to be of greater reliability. Moreover, any detailed
placement of the A. grandis complex in the A. cantoris group would involve additional
homoplasies.

Members of the A. tristrami group share features not found elsewhere in the genus, viz. no
keeling on the proximal, dorsal caudal scales (30), a short tail (31) and an often distinctive
pattern (35). The very similar A. (t.) tristrami and A. (t.) orientalis could well be sister species.
A. robustus has some features that suggest relationships elsewhere: subocular scale separated
from the mouth (22), increased number of ventrals (26a) and an irregular fourth scale row on
the fingers (29a), but none of these derived states is very strongly developed and all seem
likely to be relatively weak indicators of relationship compared with those allying A.
robustus with A. (t.) tristrami and A. (t.) orientalis.

The A. tristrami and A. erythrurus groups share some distinctive features, in particular a
high number of presacral vertebrae (4) and fragmented first and fourth supraocular scales

334 E. N. ARNOLD

(2 1 c). Furthermore, some species of each have a lateral clavula that is bifurcate at its tip ( 1 5),
so it seems reasonable to regard the two assemblages as closely related. The members of the
A. erythrurus group are all generally similar and at least some individuals of all species have
one or more azygos shields between the prefrontal scales (20) although this condition also
occurs occasionally in other forms. It is suggested that A. erythrurus and A. savignyi are sister
species on the evidence of their great similarity and frequent division of the frontonasal scale
(19). They are also the only members of the group in which the subocular scale may be
separated from the lip (22). A. boueti and A. guineensis both have distinctive features of their
own (A. boueti — nine premaxillary teeth, fragmented parietal scales, small hemipenis (7),
supraocular scales very fragmented (2 Id); A. guineensis — very asymmetrical hemipenis and
armature (8d, lOc), lateral clavula rolled) but their precise relationships to each other and to
A. erythrurus and A. savignyi are not clear. All A. guineensis examined (n = 20) have a
peculiar arrangement of nasal scales (18) which occurs as a rarity in A. erythrurus (p. 296).
However, this feature cannot be regarded as strong evidence of the close relationship of these
species within the group, for its rarity in A. erythrurus raises the possibility that its apparent
absence in A. savignyi and A. boueti may be due to inadequate sampling or to pseudoreversal
(Arnold, 198 la).

The A. pardalis group seems likely to be a monophyletic assemblage on the basis of the
strong overall similarity of its members. They also have more hemipenial asymmetry (8b or
8c) than the species placed in the A. grandis complex and the A. boskianus, A. tristrami and
A. erythrurus groups, share a high incidence of interruption of the fifth sternal rib (6) and the
number of ventral scales is also regularly high (26). The main reason for allying the A.
pardalis assemblage with these groups is that the species with the least modified hemipenis,
A. pardalis, has an armature just like the others with derived features lOa, 11 and 17. The
absence of these features in the other two species in the A. pardalis group, A. maculatus and
A. spinicauda, may be secondary, the result of the development of physical isolating
mechanisms (p. 304). The A. pardalis group shares with the A. tristrami and A. erythrurus
groups frequent bifurcation of the tip of the lateral clavula (15), some fragmentation of the
supraocular scales (2 Ib) and some tendency for high presacral vertebral counts (4). However,
the last feature is not universal and the supraoculars are less broken up than in these forms.
Because of this, the A. pardalis group is tentatively placed as a sister assemblage to them.
Within the A. pardalis group, A. maculatus and A. spinicauda may be closely related having
strongly asymmetrical hemipenes and armatures (8d, lOc) with the lateral clavula folded
sideways (16).

Holophyly of the A. scutellatus group is supported by the close similarity of its members
and their possession of a unique synapomorphy; premaxillary teeth reduced to five (2). Its
members have several other derived features that occur elsewhere and these suggest
conflicting hypotheses as to the closest relatives of the group. The main candidates are A.
schmidti, particularly the populations in the United Arab Emirates that have little sexual
variation in the number of presacral vertebrae, and all or part of the A. pardalis group.
Derived features that these share with the A. scutellatus assemblage are set out in Table 10;
the A. grandis complex shares a much smaller number, namely 26, 27 and 29. Most derived
features, eleven, are shared with A. schmidti populations from the United Arab Emirates and
only seven with the A. pardalis group of which no more than six occur in any one species.
Thus on simple count of shared characters A. schmidti would be considered clearly the more
likely sister taxon, but the likely quality of the features as indicators of relationship should
also be taken into account. In general, the features shared with A. schmidti seem rather weak
as they score badly on the weighting criteria listed by Arnold (198 la). For instance, numbers
3, 5, 6, 8d, lOc, 23, 26, 27, 29 and 33 occur in a number of other lacertid stocks; there are
additional functional reasons for thinking 8d and lOc may have evolved more than once
(p. 304); if the argument on p. 333 that the A. grandis complex is more closely related to the
A. boskianus group than to the A. cantoris assemblage is accepted, then characters 23, 26, 27
and 29 must have evolved twice within Acanthodactylus and a third independent origin

RELATIONSHIPS OF ACANTHODACTYLUS 335

Table 10 Comparison of derived features shared by the A. scutellatus group with A. schmidti and the
A. pardalis group.

A. schmidti A. pardalis group

Main United Arab A. scutellatus A. maculatus

range Emirates group A. pardalis A. spinicauda

Ib Premaxilla narrow + + +

3 Presacral vertebrae 23 or

24 in females + +

5b Little variation in number

of presacral vertebrae + + +

6 Fifth sternal rib often

interrupted + + +

8 Medial lobe of hemipenis

very reduced + + + +

1 Oc Medial side of armature

very reduced + + + +

1 6 Lateral clavula folded to

produce a z> -shaped cross section — + +

23 High number of upper

labials + + + + +

26 Increased number

ofventrals + + + + +

27 Ventrals tessellated,

at least at sides + + +

29 Four scale rows on fingers + + +

33 Young without stripes + + +,—
Strong pectination

on toes + + +

would not seem unlikely; a number of features seem to be functionally related to the
problems of living in the open, soft-sand habitats occupied by A. schmidti and the A.
scutellatus group, this is true of Ib, 3, 29, 33 and strong pectination on the digits; the coercive
selective forces likely to produce convergence of these features are discussed in the relevant
character descriptions. Finally, two features, 3 and 5, are confined in A. schmidti to a very
small part of the geographical range, the United Arab Emirates. The restricted distribution
of these characters suggest they may well have developed independently within the species. If
so, the number of features to be considered is reduced to nine. On the other hand the
relationship of the A. scutellatus assemblage to the A. pardalis group is supported by an
apparently unique hemipenial feature (16) and the high incidence of interrupted sternal ribs,
a condition not found elsewhere in the genus. Assessing such conflicting evidence is
inevitably difficult but, on balance, the author is inclined to believe that the A. scutellatus
group is most closely related to the A. pardalis assemblage.

As stated, the members of the A. opheodurus group are placed together largely on the
grounds of overall similarity which is especially marked between A. opheodurus and A.
felicis. Shared derived features are 8d, lOc and in some individuals of each species 32a; none
of these are unique to the group. Evidence for the inter-relationship of the species is
conflicting: A. felicis and A. opheodurus share 5a and 22 while the latter species and A.
masirae share 1 and 29, although 29 occurs only in a reduced form in A. opheodurus and
only in a minority of individuals.

The lack of strong derived characters makes it difficult to relate the A. opheodurus group
to other Acanthodactylus, but absence of a thickened hemipenial connector (1 7) suggests that
it is not directly related to the A. grandis-A. guineensis sequence (see Fig. 9). Nor is it clear
how this sequence relates to A. micropholis and the A. cantoris assemblage.

336 E. N. ARNOLD

Acknowledgements

The author is very grateful to the various collectors who, in the past few years have donated
often critical series of Acanthodactylus to the British Museum (Natural History). They
include D. Vesey Fitzgerald, M. D. Gallagher, J. and P. Gasperetti, D. J. Greathead,
K. M. Guichard, M. C. Jennings, M. R. K. Lambert, J. P. Mandeville, S. Moult, G. V.
Popov, T. D. Rogers, T. D. Stoner, W. Thesiger and J. O. Wade.

The following curators were kind enough to lend material in their care: E. R. Brygoo,
(Museum Nationale d'Histoire Naturelle, Paris), J. Castroviejo and P. W. Hopkins (Estacion
Biologica de Donana, Seville), M. S. Hoogmoed (Rijksmuseum van Natuurlijke Historic,
Leiden), A. E. Leviton (California Academy of Sciences, San Francisco), C. J. McCoy
(Carnegie Museum, Pittsburgh), H. Marx (Field Museum of Natural History, Chicago),
F. Tiedemann (Naturhistorisches Museum, Vienna), E. E. Williams and P. Alberch
(Museum of Comparative Zoology, Harvard), H. Marx (Field Museum, Chicago).

Some of the radiographs used in this study were produced by B. T. Clarke.

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RELATIONSHIPS OF ACANTHODACTYLUS 337

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xxviii + 289.

Gugg, W. 1939. Der Skleralring der plagiotremen Reptilien. Zool. Jb. Abt. Anal. 65 : 339-416.
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Manuscript accepted for publication 4 August 1982

Addendum

Since this paper was submitted for publication, I have had the opportunity to see the recent
article on Acanthodactylus by Dr Alfredo Salvador. (1982). In the main, we are in agreement
over species boundaries within the genus and a number of the divergencies that exist can be
attributed to using different criteria for deciding if allopatric populations merit species status
or not, always a rather subjective decision. These and other more important disagreements
are briefly considered below.

1. The A. yemenicus group of Salvador is the same as the A. opheodurus group of Arnold
(19806 and this paper) but with the addition of a new taxon, A. yemenicus. This form has
much in common with A. felicis. Unlike the other members of the group, its specific status
cannot be confirmed by sympatry, as its range is completely separate from the others. There
are considerable differences between the two populations from which A. yemenicus has been
described, Ta'izz and the Sheikh Osman-Aden area, even although these are only separated
by some 1 30 km.

2. A. erythrurus group. Salvador treats bland as a full species rather than a subspecies of A.
savignyi. Given the differences between this form and typical savignyi, this course is not
unreasonable.

3. A. pardalis group. A. pardalis, as understood here, is divided by Salvador into three full
species: A. p. pardalis becomes monotypic as A. pardalis, A. p. bedriagai becomes A.
bedriagai and the Moroccan population related to bedriagai becomes A. busacki n. sp.
These forms overlap in many morphological features.

4. A. tristrami sens. lat. Salvador regards A. tristrami, in its wide sense, as consisting of two
subspecies: A. t. tristrami, with which A. t. orientalis is synonymized, and A. t. iracensis. This
contrasts with the arrangement adopted here where orientalis is regarded as separable from
tristrami and iracensis is synonymized with orientalis. A careful examination of the types of
all three forms and of most other available material convinces me that the latter course is
more appropriate. A. t. iracensis cannot be separated from orientalis on the basis of the

RELATIONSHIPS OF ACANTHODACTYLUS 339

features mentioned by Schmidt (1939), namely lower transverse dorsal count, less vivid
colour pattern and more sharply pectinate toes; nor does it differ significantly in any of the
other features investigated. On the other hand, typical tristrami differs from orientalis,
including iracensis, not only in its larger size, more numerous dorsal scales and hemipenial
structure, but usually also in its deeper snout with convex upper profile, absence of a
denticulation on the anterior edge of the ear and virtual lack of pectination on the toes. In
addition, the first supraocular is more fragmented (tristrami-n— 10, average number of
fragments on each side 5.4, range 3-10; orientalis-n= 17, average number of fragments on
each side 2.8, range 1-6).

5. A. scutellatus group. Salvador divides A. scutellatus, as understood here, into A.
scutellatus in the east and A. dumerilii in the west. The two supposed species are said to
approach each other in Mali and Algeria but not to integade. I have re-examined the
BM(NH) material from Mali that Salvador assigns to A. scutellatus and A. dumerilii and can
find no differences in the features that are said to separate them, namely transverse ventral
count, snout shape and number of rows of supraciliary granules. Where A. scutellatus and A
dumerilii approach each other around the Algerian-Tunisian border, I again find no
consistent differences in snout shape as mentioned by Salvador, and although there are
average differences in degree of fragmentation of the fourth supraocular scale, there is
substantial overlap. I consequently regard the separation of A. dumerilii from A. scutellatus
as unproven.

Salvador divides his A. dumerilii into two subspecies: A. d. dumerilii in Senegal, southwest
Mauretania and Mali and A. d. exiguus in Algeria and Morocco. The former is said to have
12 instead of 14 longitudinal rows of ventral scales, two instead of one row of supraciliary
granules and longer legs. In material I have examined, I find that two rows of supraciliary
granules are often absent in the area where A. d. dumerilii is reported and leg length is
variable. Furthermore, there is a very large intergrade area between the two subspecies where
other characters vary clinally. It scarcely seems worth while naming such poorly defined
entities, especially when A. scutellatus varies so substantially elsewhere in its large North
African range and no subspecies names are assigned.

6. The diagnosis of Acanthodactylus given on p. 8 does not fully differentiate the genus
from Meroles or Eremias.

Salvador, A. 1982. A revision of the lizards of the genus Acanthodactylus (Sauria: Lacertidae). Bonn,
zool. Monogr. 16: 1-167.

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Titles to be published in Volume 44

Observations on the systematics of the genus Difflugia in
Britain (Rhizopoda, Protozoa).
By Colin G. Ogden

Miscellanea

A review of the Euplotidae (Hypotrichida, Ciliophora).

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Osteology, genitalia and relationships of the Acanthodactylus
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Morphological studies on some Difflugiidae from Yugoslavia
(Rhizopoda, Protozoa).

By Colin G. Ogden & Andjelija Zivkovic

Printed by Henry Ling Ltd, Dorchester

Bulletin of the

British Museum (Natural History)

Morphological studies on some

Difflugiidae from Yugoslavia

(Rhizopoda, Protozoa)

Colin G. Ogden & Andjelija Zivkovic

Zoology series Vol 44 No 6 30 June 1983

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ISSN 0007-1498 Zoology series

Vol44No6pp341-375
British Museum (Natural History)
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London SW7 5BD Issued 30 June 1983

Morphological studies on some Difflugiidae from
Yugoslavia (Rhizopoda, Protozoa)

Colin G. Ogden

Department of Zoology, British Museum (Natural History), Cromwell Road, London
SW7 5BD

Andjelija Zivkovic

Institute for Biological Research, University of Belgrade, 29, Novembra 142, 11000
Belgrade, Yugoslavia

Contents

Introduction 341

Materials and methods 341

Systematic descriptions 342

Difflugia 342

Cucurbitella 369

Pontigulasia 369

Summary 373

References 374

Introduction

Recent studies (Ogden, 1979, 19800, b, 1983; Ogden & Fairman, 1979) on the shell
morphology of specimens belonging to the family Difflugiidae, have shown that detailed
examination of these structures aid identification at the species level. It is now possible using
the scanning electron microscope to demonstrate differences in shell structure and to
examine more easily the type and arrangement of materials used in these complex con-
structions. Earlier workers were handicapped in similar examinations by the limited
resolution of reflective optical microscopy. This made comparisons of shell structure
difficult due to the different densities of the shell ranging from opaque to transparent, and
sometimes the shape made a complete survey impracticable, ovoid or circular shells being
particularly awkward. The present work is based on specimens collected in Serbia,
Yugoslavia, from an area of peat bogs located on the high plateau at 1200 m, now submerged
by the artificial lake 'Vlasina', which was formed by damming the river Vlasina and flooding
a depression. A limnological study of this lake by Milovanovic & Zivkovic (1956) gives
information relating to the chemical and biological conditions during the initial formation of
this feature.

There are several reasons for our interest in the Difflugiidae of Yugoslavia, no previous
records of testate amoebae are available for this region, there appears to be a similarity of this
fauna with that reported from Africa by Gauthier-Lievre & Thomas (1958) and specimens of
the so-called 'cosmopolitan' species are available for comparison with those already
described from the British Isles. Furthermore, the presence of several compressed species of
Difflugia is unusual, as these forms appear to be rare.

Materials and methods

Samples were collected in September, 1947 from a pond 'Godzina bistrica' located at the

Bull. Br. A/MS. nat. Hist. (Zool.) 44(6) : 34 1-375 Issued 30 June 1 983

342 C. G. OGDEN & A. 2lVKOVIC

margin of a peat bog, and preserved in formalin. The samples were divided into two in 1980,
one half was deposited in the Zoology Department, British Museum (Natural History) and
the other was retained in Yugoslavia. This report is based mainly on the BM(NH) specimens
but reference is also made to those in the other sample. Selected shells from the sample were
washed in several changes of distilled water, then individuals were prepared for scanning
electron microscopy using the technique described by Ogden (1979). The prepared stubs
were examined using a Cambridge Stereoscan SI 80 operating at 10 kV and the results
recorded on Ilford HP5 film.

Systematic descriptions

The species ofDifflugia are listed in alphabetical order, except for the new species which are
described last and D. gramen which is described with D. schurmanni for comparative
purposes. The single species of the genus Cucurbitella and two species of Pontigulasia are
described after the species of Dijflugia. The measurements for total body length includes
aboral processes, unless otherwise stated, breadth and diameter of aperture are taken as the
widest point, the latter is an internal measurement.

Genus DIFFLUGIA Leclerc, 1815

Difftugia acuminata Ehrenberg, 1838

A single specimen, 199 urn long, 85 urn in breadth, with an aperture diameter of 37 urn, was
examined and seen to be identical to those already described (Ogden, 1979). Significantly the
distinctive organic cement pattern of this species, a network in which each mesh is further
divided by a smaller network, was present.

Difflugia acutissima Deflandre, 193 1

DESCRIPTION. The shell is transparent, pyriform with the sides tapering evenly from about
the mid-body region and terminating usually with a sharp point (Fig. la). It is composed
mainly of flattish pieces of quartz to give a smooth surface, with organic cement sometimes
seen as part of the shell matrix (Fig. Ic). The cement is usually in the form of a network about
400 nm in diameter with walls 200 nm thick, and each mesh is covered by a smooth
membrane (Fig. Id). The aperture is circular and surrounded by small to medium particles
(Fig. Ib). One specimen had an oblique aperture and a misaligned aboral protuberance (Fig.
le), the latter being only partially sealed (Fig. 10, but was considered to agree with the
general description of this species in all other respects.

MEASUREMENTS (in um). Four specimens: body length 178-217, breadth, 80-107, diameter
of aperture 47-51.

GEOGRAPHICAL DISTRIBUTION. Argentina (Dioni, 1970), Chad (Gauthier-Lievre & Thomas,
1958), Congo (Chardez, 1964), Gold Coast, Morocco (Gauthier-Lievre & Thomas, 1958),
United States of America (Leidy, 1879), Venezuela (Deflandre, 1931).

REMARKS. This species was initially described by Deflandre (1931) who considered that it
was distinct from D. acuminata and its varieties by the sharpness of the aboral extremity. It
differs from D. ventricosa, also described by Deflandre (1926) from Venezuela, by having a
much wider body and aperture. The general body dimensions are similar to those given for
D. distenda by Ogden (1983), which was a variety of D. acuminata but this species is curved
aborally to a small tubular horn. The problems of differentiating between species with aboral
horns or spines are emphasized in two publications by Chardez (1961 & 1973), which show
several figures supposedly pertaining to the same species. It is clear that concise specific

DIFFLUGIDAE FROM YUGOSLAVIA

343

Fig. 1 Difflugia acutissima : a, lateral view x600; b, apertural view x360; c, detail of organic
cement pattern x 14000; d, portion of shell surface to show organic cement between particles
X 6600; e, specimen with oblique aperture and non-central aboral spine x 420; f, detail of partial
closure at extremity of aboral spine x 1900.

344 C. G. OGDEN & A. 2IVKOVIC

identification of specimens must await morphogenetic evidence of natural variation of this
feature within a species.

Difflugia bicornis Penard, 1890

DESCRIPTION. The shell is transparent, ovoid or spherical with usually two, but occasionally
one aboral spines (Figs 2a & b). Of the three specimens examined only one had a single long
aboral spine. The surface is rough, thin and composed of a mixture of small to medium
particles of quartz, with the occasional addition of either a portion of diatom frustule or a
siliceous flagellate cyst. Each aboral spine is roughly pointed and composed of small
particles. A network of organic cement is sometimes seen between particles (Fig. 2d). It is in
the form of a sheet with each mesh being separated by small walls, about 80 nm thick. The
mesh is irregular, about 300-400 nm in diameter, and each enclosure often has a small inner
circular wall with arms connecting it to the mesh wall (Fig. 2e). The aperture is usually
circular and surrounded by a mixture of particles (Fig. 2c).

MEASUREMENTS (nm). Three specimens: body length 75-85, breadth 39-53, diameter of
aperture 19-23.

GEOGRAPHICAL DISTRIBUTION. Germany (Penard, 1890; Jung, 1936), Guatemala, Mexico
(Laminger, 1973), Switzerland (Penard, 1902).

REMARKS. This species was initially described as a distinct species by Penard (1890) but was
later considered (Penard, 1902) to be a small form of D. elegans, and he illustrated the vari-
ability of the shell in this form with several figures, including specimens with either one or
two aboral spines. The specimens reported here have a fragile shell and are in good agree-
ment with the original description of D. bicornis, the body lengths without the spines or
horns being about 60 um which is near to Penard's 50-60 urn. The contrast between these
specimens and those of D. elegans studied recently (Ogden, 1979), which had robust shells
and varied in body length between 1 1 3-1 58 um, is marked. In the absence of information on
other small forms identified as D. elegans, we have decided to use the earlier description of
D. bicornis and consider the present specimens as a distinct species.

Difflugia bryophila (Penard, 1902)

A single specimen, 124 um in body length, 53 um broad with an aperture diameter of 1 7 um.
It was identical to those described by Ogden (1 983).

Difflugia capreolata Penard, 1 902

DESCRIPTION. The shell is opaque, thick, pyriform with a restriction of the neck at a position
about one-third of the total body length, before it swells into the main body (Fig. 3a). It is
composed of small to medium pieces of angular quartz, with small areas of organic cement as
part of the matrix (Fig. 3c). This cement is in the form of a smooth sheet with irregular
perforations (Fig. 3d), the reason that there is no apparent pattern to these perforations may
be due to these areas being in thin strips rather than a more open arrangement. Each
perforation has a mean diameter of 200 nm. The aperture is circular and surrounded by a
regular distribution of medium particles (Fig. 3b).

MEASUREMENTS (in um). One specimen: body length 225, breadth 128, diameter of aperture
58.

GEOGRAPHICAL DISTRIBUTION. Argentina (Dioni, 1970; Lena & Zaidenwerg, 1975),
Germany (Schonborn, 1965), Russia (Kourov, 1925), Tunisia (Gauthier-Lievre & Thomas,
1958), Sudan (Gauthier-Lievre & Thomas, 1958), Switzerland (Penard, 1902).

REMARKS. This species although it is large and has a distinctive outline, does not appear to be
common and is rarely found in large numbers.

DIFFLUGIIDAE FROM YUGOSLAVIA

345

Fig. 2 Difjlugia bicornis: a, lateral view of specimen with two aboral spines x 1400; b, lateral
view of specimen with single aboral spine x 760; c, apertural view x 820; d, portion of shell
surface to illustrate the organic cement (arrowed) x7500; e, detail of organic cement x 35000.

346

C. G. OGDEN & A. 2IVKOVIC

Fig. 3 Difflugia capreolata: a, lateral view x400; b, apertural view x340; c, shell surface
showing small areas of organic cement x 3000; d, detail of organic cement pattern x 1 3000.

Difflugia corona Wallich, 1864

DESCRIPTION. The shell is brown, spherical or ovoid with distinct cone-like spines projecting
from the aboral half of the body (Fig. 4a-d). The main body is composed of a mixture of
small to medium particles of quartz arranged to give a relatively smooth shell. The spines are
randomly arranged, varying between two and eight in number, made of small particles and
are usually finely pointed. Organic cement in the form of a network is sometimes seen where
particles meet. The aperture is circular and surrounded by a distinct denticular collar. There

DIFFLUGIIDAE FROM YUGOSLAVIA

347

, , ^~'-^~
r^%£'j^^&

Fig. 4 Difflugia corona: a, lateral view of specimen with six spines x430; b, apertural view of a,
note the regular arrangement of twelve teeth x 330; c, lateral view of another specimen x 240; d,
apertural view of c, to show sixteen thickened teeth x 240.

are usually between ten to twelve tooth-like projections, although one specimen in the
present sample had sixteen (Fig. 4d). They are arranged evenly, usually being finely
pointed, but as seen in Fig. 4d compression of the teeth makes the projections thicker and the
outer curvature of the collar more rounded.

MEASUREMENTS (in um). Fourteen specimens: body length 126-190, breadth 126-177,
diameter of aperture 53-86.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Argentina
(Boltovskoy & Lena, 1974; Lena & Ziadenwerg, 1975; Vucetich, 1970), Austria (Laminger,
1975), Belgium (Chardez, 1961, 1980), Brazil (Green, 1975), British Isles (Ogden & Hedley,
1980; Wallich, 1864), Chad (Gauthier-Lievre & Thomas, 1958), Congo (Chardez, 1964;
Gauthier-Lievre & Thomas, 1958), Czechoslovakia (Ertl, 1965), Germany (Penard, 1890),
Hungary (Bereczky, 1973), India (Wallich, 1864), Java (BartoS, 1963), Netherlands
(Hoogenraad & Groot, 1940), Roumania (Godeanu et al, 1973), Russia (Kourov, 1925),

348

C. G. OGDEN & A. 2IVKOVIC

•

Fig. 5 Difflugia difficilis: a, lateral view x 950; apertural view x 760; c, detail of aperture to show
short collar and organic cement (arrowed) between particles x 2 100; d, detail of organic cement
x 18000.

Senegal, Sudan and West Africa (Gauthier-Lievre & Thomas, 1958), South Africa (Oye,
1931), Switzerland (Penard, 1902), United States of America (Leidy, 1879).

REMARKS. This species is truly 'cosmopolitan' having been reported from most continents,
but these sightings are probably due to the ease in observing the prominent features of this
large, distinctive shell in any sample. Although Jennings (1916, 1937) showed that variation
of both teeth and spines occurred under cultural conditions, subsequent authors have
continued to designate forms and varieties based on these structures. It could be argued that
Jenning's observations were made on rough cultures and that clonal cultures would behave
differently, or that the medium used was limiting in some way. Nevertheless, some of the
reported features could easily be considered to represent natural variation.

DIFFLUGIIDAE FROM YUGOSLAVIA 349

Difflugia decloitrei Godeanu, 1 972

A single specimen similar to those recently described by Ogden (1983) was found. It is
possibly an encysted form as the aperture was blocked with several flat pieces of quartz
bound by organic cement.

MEASUREMENTS (in um). One specimen: body length 79, breadth 52, diameter of aperture 22.

Difflugia difficilis Thomas, 1954

DESCRIPTION. The shell is transparent, ovoid, thin with a small apertural collar (Fig. 5a). It is
composed of small to medium pieces of angular quartz arranged to make a relatively smooth
surface, with the occasional projection of some particles. A network of organic cement is
frequently seen as part of the shell matrix (Fig. 5c). The mesh of this network is open, each
opening being about 350 nm wide with dividing walls 200 nm thick (Fig. 5d). A short collar
made mainly of regularly arranged smallish particles, surrounds the circular aperture (Figs
5b & c).

MEASUREMENT (in um). One specimen: body length 8 1 , breadth 56, diameter of aperture 18.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Argentina (Lena
& Zaidenwerg, 1975), Congo (Chardez, 1964), France (Thomas, 1954), Ivory Coast
(Gauthier-Lievre & Thomas, 1958), Roumania (Godeanu et al, 1975), Sudan (Gauthier-
Lievre & Thomas, 1958).

REMARKS. This specimen has similar dimensions to those given for D. difficilis and D.
kabylica by Gauthier-Lievre & Thomas (1958). It differs from D. kabylica in having a
smaller aperture which does not have a flattened irregular outline. It is most similar to D.
difficilis, although it does not have 'une excoissance peu proeminente' as initially described
by Thomas (1954). However this species was later reported (Gauthier-Lievre & Thomas,
1958) to vary a great deal in body outline and often the aboral protuberance is absent. The
feature that is characteristic of this species is the small collar and in the absence of further
specimens the present specimen is considered to be D. difficilis.

Difflugia gramen

Seep. 357.

Difflugia labiosa Wailes, 1919

Two specimens of this species identical to those recently redescribed by Ogden (1983) were
found.

MEASUREMENTS (in um). Two specimens: body length 176 & 177, breadth 111, diameter of
aperture 45 & 52.

Difflugia lata Jung, 1942

Difflugia oblonga forma lata Jung, 1942

DESCRIPTION. The shell is opaque, pyriform having a rough surface composed of a mixture of
mainly small to medium pieces of quartz, with an occasional large particle added (Fig. 6a).
One specimen has a curved or malformed aboral extremity (Fig. 6c), but in all other respects
is similar to the original description. Organic cement in the form of a network is seen as part
of the shell matrix (Fig. 6d). The mesh of the network is open and has a mean diameter of
350 nm with walls 200 nm thick, although the walls often fuse to give larger areas of cement
(Fig. 6e). The aperture is circular and surrounded by both small and medium particles
arranged to give a somewhat irregular outline (Fig. 6b).

350

C. G. OGDEN & A. ZlVKOVIC

Fig. 6 Dijjlugia lata: a, lateral view x 590; b, apertural view x 420; c, specimen with malformed
aboral extremity x 400; d, shell surface with organic cement as part of matrix x 3600; e, detail of
organic cement x 13500.

MEASUREMENTS (in urn). Two specimens: body length 137 & 149, breadth 90 & 103,
diameter of aperture 42 & 46.

GEOGRAPHICAL DISTRIBUTION. Chile (Jung, 1942).

REMARKS. This species is known apparently only from the initial description (Jung, 1942) as
a new form of D. oblonga. Although measurements are not given in the original text, from

DIFFLUGIIDAE FROM YUGOSLAVIA

351

Fig. 7

••••^^^^^^^^•••••^^^^^^^••••••••••••••••^^^•l •••••••••••••••••••••••••''•••I

Difflugia levanderi: a, lateral view x730; b, apertural view x530; c, portion of shell
surface with organic cement (arrowed) x 7000.

the figure these are estimated to be body length 157 um, breadth 81 urn and diameter of
aperture 43 urn, which agree well with the present specimens. Note that our Fig. 6c
compares well with that given by Jung (1942). This species is considered to be distinct from
D. oblonga (see Ogden, 1979) in its stout pyriform body, wide aperture and organic cement
pattern.

Difflugia levanderi Playfair, 1918

DESCRIPTION. The shell is ovoid or almost spherical, composed of flattish and angular pieces
of quartz to give a regular outline (Fig. 7a). The particles appear to overlap and produce a
robust structure with a network of organic cement, which is seen infrequently, binding the
particles (Fig. 7c). Details of the surface are restricted because all the examined specimens
have a slight covering of small debris, this latter material is clearly no part of the shell
structure. The aperture is circular, well defined and surrounded by small particles (Fig. 7b).

MEASUREMENTS (in um). Five specimens: body length 95-104, breadth 76-92, diameter of
aperture 32-40.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Australia
(Playfair, 1918), Chile (Jung, 1942), Morocco and Tunisia (Gauthier-Lievre & Thomas,
1958).

REMARKS. The descriptions of both Levander (1894) and Playfair (1918) refer to specimens
having a similar shape but differing in size and composition. The larger being robust with a
coarse appearance, whilst the smaller had a chitinous shell with a scattering of particles.
Unable to differentiate them Playfair (1918) described them as a new species D. levanderi.

C. G. OGDEN & A. 2IVKOVIC

Fig. 8 Difflugia lismorensis: a, latero-apertural view x 640; b, apertural view to illustrate the
thickened teeth and collar x470; c, part of shell surface with overlay of extraneous material
X 3400.

Fortunately, he created a precedence by initially describing the larger specimens, which are
now considered to represent D. levanderi. Specimens similar to D. levanderi except for being
smaller and having a thin shell whose particles did not overlap, were described by Godeanu
(1972) as a new species D. decloitrei, and these are considered to be identical to the smaller
animals described by Levander (1894), Playfair (19 18) and redescribed by Ogden (1983).

Difflugia lismorensis Playfair, 1918

Difflugia lismorensis var. quinquelobata Gauthier-Lievre & Thomas, 1958
Difaugia lismorensis var. elongata Gauthier-Lievre & Thomas, 1 958

DIFFLUGIIDAE FROM YUGOSLAVIA 353

DESCRIPTION. The shell is either elongate or ovoid, thick, composed of small to medium
pieces of quartz arranged to give a rough surface (Fig. 8a). All the specimens examined had a
proportion of the surface covered with an overlay of small extraneous material (Fig. 8c),
nevertheless, the portions of actual surface visible had only strands of organic cement as part
of the shell matrix. The aperture has five lobes which are equally spaced, strong, blunt,
tooth-like extensions (Fig. 8b). Often the strengthening around these lobes, usually with
small particles, gives it a collar-like appearance (Fig. 8b).

MEASUREMENTS (in um). Three specimens: body length 132-144, breadth 96-104, diameter
of aperture 3 6-4 5.

GEOGRAPHICAL DISTRIBUTION. Argentina (Vucetich, 1970), Australia (Playfair, 1918), Brazil
(Green, 1973), Chad (Gauthier-Lievre & Thomas, 1958), Congo (Chardez, 1964; Gauthier-
Lievre & Thomas, 1958), Gold Coast, Morocco and Sudan (Gauthier-Lievre & Thomas,
1958).

REMARKS. Playfair (1918) described D. lismorensis as having an ovoid or sub-globular shell
with a six-lobed aperture, and added two varieties trilobulata and crucifera which had three
and four lobes respectively. Since that time two more varieties with five lobes, from Africa,
have been described by Gauthier-Lievre & Thomas (1958). They suggested the name
quinquelobata for the ovoid variety and elongata for the specimens with an elongate body,
the former has subsequently been reported again in Africa by Chardez (1964). Vucetich
(1970) after examining about 50 specimens with seven lobes from Argentina, concluded that
these were otherwise identical with D. lismorensis and she did not consider that differences
in the number of lobes warranted specific designation. Until examples of this species from
Australia, Africa and South America are compared, we agree with Vucetich (1970) that her
specimens, plus those of Gauthier-Lievre & Thomas are best described as D. lismorensis.

Difflugia lithophila (Penard, 1902), Gauthier-Lievre & Thomas, 1958

Difflugia hydrostatica var. lithophila Penard, 1902

A single specimen identical to that described by Ogden & Hedley (1980) was examined. It is
slightly smaller than previous records being 93 um in body length, 67 urn breadth and having
an apertural diameter of 32 um; however, it is proportionally similar. African specimens
appear to have a larger range of body length, 100-170 um (Gauthier-Lievre & Thomas,
1958), to those from Europe 99-1 40 um (Penard, 1902; Thomas, 1954).

Difflugia lucida Penard, 1 890

A single specimen was examined, it measured 61 um in body length, 39 um broad, 19 um
depth with an aperture diameter of 22 um. Although slightly smaller than those examined in
an earlier study (Ogden, 1983) it was otherwise identical.

Difflugia manicata Penard, 1 902

Two specimens 76 & 78 um long, 39 & 43 um in breadth, with aperture diameters of 14 &
17, were examined and found to be identical to those recently redescribed by Ogden (1983).

Difflugia mica Frenzel, 1892

DESCRIPTION. The shell is brownish, spherical or ovoid sometimes with a shallow apertural
collar (Fig. 9a). It is composed of flattish pieces of quartz arranged to give a relatively smooth
surface, although one specimen has most of the surface obscured by extraneous material.
Organic cement is seen infrequently between particles but is more evident around the
aperture. The cement around the aperture is apparent as a thin layer on the surface of some
outer particles (Fig. 9c), but is a concentration of strands, some apparently fused, on the

354

C. G. OGDEN & A. 2IVKOVIC

Fig. 9 Difjlugia mica: a, lateral view showing the arrangement of flattish particles x 1400; b,
apertural view x 1 100; c, organic cement at outer limit of apertural concentration x 17000; d,
concentration of organic cement on apertural lip, note the fusion of some strands x 20000; e,
general appearance of organic cement network x 29000.

DIFFLUGIIDAE FROM YUGOSLAVIA

355

Fig. 10 Difflugia nodosa: a, apertural view x270; b, view to illustrate lateral compression
x 160; c, lateral view showing the lateral wings and aboral protuberance x970; d, portion of
shell surface close to aperture, note that the organic cement is torn (arrowed) x4600; e, & f,
detail of organic cement pattern x 14000 & x 2 1000.

apertural lip (Fig. 9d). The general structure is of a network with an irregular mesh about 300
to 500 nm in diameter, with dividing walls about lOOnm thick (Fig. 9e). The aperture is
circular, well denned, usually with an organic margin and sometimes with a collar (Fig. 9b).

MEASUREMENTS (in um). Two specimens: body length 55 & 60, breadth 46 & 55, diameter of
aperture 19 & 18.

356 C. G. OGDEN & A. 2lVKOVIC

REMARKS. These specimens are in good agreement with the description given by Ogden
(1983). They are described again here to include information of the organic cement pattern.

Difflugia microclaviformis (Kourov, 1925)

The two specimens examined here fall within the range of body lengths given by Kourov
(1925) of 139-1 60 um, their respective measurements are: — body length 141 & 163 urn,
breadth 66 & 75 um and diameter of aperture 19 & 21 um. Furthermore, they are in good
agreement with the recent redescription of slightly larger specimens given by Ogden (1983).

Difflugia nodosa (Leidy, 1879) comb. nov.
Difflugia pyrif or mis var. nodosa Leidy, 1879 and in Penard, 1902
Dijflugia oblonga var. nodosa Leidy, 1 879 in Gauthier-Lievre & Thomas, 1958

DESCRIPTION. The shell is thick, opaque, pyriform with the main body compressed to give
two large lateral wings and an aboral extension or protuberance (Figs lOb & c). It is
composed of a mixture of various sized pieces of quartz, which unfortunately in the present
specimen is overlaid with debris. Nevertheless, some organic cement was observed close to
the aperture (Fig. lOd); it is in the form of a network with the open mesh having a mean
diameter of 200 nm and walls 200 nm thick (Figs lOe & f)- The aperture is circular and
surrounded by a regular arrangement of small particles (Fig. 1 Oa).

MEASUREMENTS (in um). One specimen: body length 367, breadth 241, depth 140, diameter
of aperture 53.

GEOGRAPHICAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Belgium
(Chardez, 1980; Chardez & Gaspar, 1976), Congo (Gauthier-Lievre & Thomas, 1958),
Germany (Laminger, 1973; Schonborn, 1962), Ivory Coast (Gauthier-Lievre & Thomas,
1958), Netherlands (Hoogenraad & Groot, 1940), Roumania (Godeanu et al, 1973), Russia
(Kourov, 1925), Sudan (Gauthier-Lievre & Thomas, 1958), United States of America (Leidy,
1879).

REMARKS. This species has consistently been described as a variety of/), oblonga, initially
Leidy (1879) remarked that it was a 'striking variety' distinguished by its unusually large size,
compressed body and three conical eminences which varied a great deal in their develop-
ment. Although Leidy (1879) reported it as being abundant on one particular occasion, so
that one drop of ooze contained several dozen individuals, since that time no other reports
have been so fruitful with specimens. Nevertheless, we consider that this variety is best
treated as a distinct species which differs from the typical D. oblonga in the features
described above and the organic cement pattern.

Difflugia oblonga Ehrenberg, 1838

Two specimens with the typically rough shell recently redescribed by Ogden & Fairman
(1979) were examined; they measured: body length 232 & 263 um, breadth 1 12 & 109 um
and diameter of aperture 46 & 41 um.

Difflugia parva (Thomas, 1954)

The specimens of this species agree well with the redescription given by Ogden (1983) having
a relatively smooth shell and areas of organic cement as part of the shell matrix; body length
143-203 urn, breadth 78-94 urn and diameter of aperture 24-32 um.

Difflugia pristis Penard, 1902

Four specimens, body length 37-62 um, breadth 27-38 um and diameter of aperture
13-16 um, having shells composed mainly of quartz particles but with some added diatom
frustules, were examined.

DIFFLUGIIDAE FROM YUGOSLAVIA 357

Difflugia pulex Penard, 1902

Two small ovoid specimens, body length 30 & 32 um, breadth 22 & 24 um with diameter of
aperture 10 & 1 1 um were examined.

Difflugia rubescens Penard, 1 89 1

Two specimens, body length 5 & 62 um, breadth 34 & 40 um and diameter of aperture
1 5 um were examined.

Difflugia gramen Penard, 1902

DESCRIPTION. The shell is transparent or light brown, spherical tapering towards the
aperture (Fig. 1 la). It is composed of a mixture of small to medium pieces of quartz, bound
by an organic cement network (Fig. lie). A ring of small pores surrounds the aperture (see
Ogden, 1 980b) which is trilobed and bordered by an irregular raised rim (Fig. 1 1 b).

MEASUREMENTS (in um). See Table 1 .

REMARKS. A brief description of this species is included so that a direct comparison can be
made with specimens of Difflugia schurmanni Oye, 1 932 described below.

Table 1 Range of measurements (in um) of four ovoid species of Difflugia.

Length
(L)

Breadth
(B)

Diameter of
aperture
(da)

B/L

da/L

da/B

D. achlora

(E)

49-54

43^6

16-17

D. schurmanni

(Y)

50-70

36-52

18-26

74 ±0-05

35±0-04

•48 ±0-03

D. gramen

(Y)

69-90

51-81

26-32

84±0-08

36+0-03

044 + 0-04

D. gramen

(E)

89-117

70-112

23-39

0-96+0-07

34±0-04

36 ±0-03

D. lobostoma

(E)

123-186

106-166

32-60

87±0-06

29 ±0-03

33 ±0-02

n = number of specimens; E = Norfolk, England (see Ogden, 1 9806); Y = Yugoslavia (present work)

Difflugia schurmanni Oye, 1 932

DESCRIPTION. The shell is transparent, elongate ovoid, tapering equally to the aperture and
aboral extremity (Fig. 1 Id). It is composed mainly of flattish pieces of quartz arranged to give
a smooth and rather fragile appearance. The particles are bound by organic cement, similar
to that described for D. gramen, but because the particles fit closely together cement is not
seen as frequently as in that species. The aperture is trilobed with the dividing projections
less pronounced in apertural view (Fig. lie) compared with those of D. gramen, and this
gives it a more open outline especially as the shell has a smaller breadth (see Table 1). In
addition, the surrounding ridge is often not as well defined although in lateral view the lobes
are more prominent (Fig. 1 Id). A ring of small pores surrounds the aperture, similar to those
described for D. gramen (see Ogden, 19806).

MEASUREMENTS (in um). See Table 1.

GEOGRAPHICAL DISTRIBUTION. Brazil (Green, 1975), Congo (Gauthier-Lievre & Thomas,
1958), Guatemala (Laminger, 1973a), Senegal (Gauthier-Lievre & Thomas, 1958), South
Africa (Oye, 1932), Sudan (Gauthier-Lievre & Thomas, 1958).

358

C. G. OGDEN & A. ilVKOVIC

K-

•r:f ;<;"*'.
•ry-^'^t

*'-^/;

4 'H

Fig. 11 Difflugia gramen: a, lateral view x 1000; b, apertural view, note the small aperture
opening but well denned surrounding ridge x610; c, detail of organic cement pattern x7500
Difflugia schurmanni; d, lateral view, note the different arrangement of particles and denned
apertural lobes x 1500; e, apertural view to illustrate wide opening and less pronounced ridge
xlOOO.

DIFFLUGIIDAE FROM YUGOSLAVIA

359

REMARKS. Reports of this species appear to be confined to tropical countries, but this may be
due to it being reported elsewhere as D. gramen. The measurements of specimens for the
three similar species, D. achlora, D. gramen and D. lobostoma, redescribed recently (Ogden,
1980&) from England are listed in Table 1 for comparison. It would appear that the
information given does not help to resolve specific identification, which still depends on the
measurement of overall body length and differences in shell structure. The significance of
these latter features must await morphological studies on clonal cultures.

D. schurmanni is considered to be distinct from D. gramen in being smaller, more
elongate, having a smooth surface composed of flattish particles and a more open aperture.

Difflugia smilion Gauthier-Lievre & Thomas, 1958

DESCRIPTION. Unfortunately the only specimen was broken during preparation. The shell is
transparent, elongate with a distinct aboral conical protuberance. It is composed mainly of
medium to large, angular or flat pieces of quartz to give a rough surface. Organic cement is
seen at the junctions of these particles as enclosed spheres, or spheres with small openings, or
as a thick rimmed circle with four equal openings (Fig. 12b & c). The spheres are about
600 nm in diameter, the walls of the circle are about 1 50 nm thick and the internal openings
vary between 1 50-220 nm. The aperture is circular and surrounded mainly by medium sized
particles (Fig. 12a).

Fig. 12 Difflugia smilion: a, apertural view to show arrangement of surrounding particles; b & c,
detail of organic cement pattern x 2 1 000 & x 1 3000.

Table 2 Range of measurements (in um) of D. tuberculata and D. wailesi

Length

Breadth

Diameter of

(L)

(B)

aperture (da)

B/L

da/L

da/B

D. wailesi (i)

(Y)

84-1 1 1

63-103

27-40

85 + 0-09

32+0-03

38 + 0-01

D. wailesi (ii)

(Y)

73-103

62-82

22-28

8310-07

3010-03

36 + 0-02

D. wailesi

(E)

96-112

79-90

29-34

•80 + 0-03

30 + 0-01

38 + 0-02

D. tuberculata

(Y)

96-116

74-94

31-35

•82 + 0-05

3110-02

•37 + 0-03

D. tuberculata

(E)

102-152

88-141

29-44

•89+0-10

•29 + 0-04

•33+0-02

n = number of specimens; (i) = typical specimens with indented aperture; (ii) = specimens with circular aperture;
E = Norfolk, England (see Ogden, 1 9806); Y = Yugoslavia (present work)

360 C. G. OGDEN & A. ZlVKOVIC

GEOGRAPHCAL DISTRIBUTION. Algeria (Gauthier-Lievre & Thomas, 1958), Argentina (Dioni,
1970), Belgium (Chardez, 1980; Chardez & Caspar, 1976), Brazil (Green, 1975), Congo
(Chardez, 1964), France (Thomas, 1953, 1954), Ivory Coast (Gauthier-Lievre & Thomas,
1958), Poland (Moraczewski, 1965), Roumania(Godeanu^a/., 1973).

REMARKS. This specimen is similar in all respects to the description given by Thomas (1953),
the body length being about the same, 226 urn, although here it is an estimated figure because
of the state of the specimen. No value is given for the breadth, but it was seen to be only
slightly larger than the aperture which has a diameter of 4 1 u,m.

Dijflugia tuberculata (Wallich, 1864)

Specimens with the typical protuberances were examined and the measurements are
included in Table 2.

Dijflugia wailesi Ogden, 1980
Difflugia tuberculata var. minor Wailes, 1919

DESCRIPTION. Two distinct forms of this species are present in the examined material, both
are figured and described.

In the typical form the shell is transparent, ovoid but tapering slightly near the aperture
(Fig. 13a). It is composed mainly of flattish pieces of quartz and siliceous elements arranged
to give a smooth surface (Fig. 1 3a). The aperture is polygonal with usually five but occasion-
ally six indentations and bordered by a small lip (Fig. 13b). A ring of about ten small pores is
often seen just posterior to the apertural rim.

In the other form the shell is ovoid but more markedly tapered towards the aperture (Fig.
13c). The aperture is circular with no indentations (Fig. 13d), but with a similar small ridge
as in the typical form. There are nine or more small tooth-like projections inside the
apertural rim on a level with the main body of the shell (Fig. 13e), these tooth-like structures
are similar to those sometimes seen at the apex of each apertural projection in the polygonal
aperture specimens.

MEASUREMENTS (in um). See Table 2.

REMARKS. The similarity of dimensions between the present specimens and those reported
recently from Norfolk, England, highlight the difficulty of differentiating the two species D.
tuberculata and D. wailesi. A further division of D. wailesi is not desirable unless supported
by strong morphological evidence, therefore, although the specimens are reported as two
groups no particular significance is attached to these differences.

Difflugia balcanica sp. nov.

DESCRIPTION. The shell is transparent, ovoid or roughly circular with an aboral cone or spine
and laterally compressed, the shape resembles either an arrow-head or a leaf (Figs 14a & c).
It is composed of a mixture of small to large pieces of mainly flattish quartz, arranged to give
a relatively smooth but irregular surface, unfortunately the illustrated specimen has some
overlying debris scattered on the anterior third of the body. An open network of organic
cement is seen between the particles. The aperture is roughly circular and surrounded by
small or medium pieces of quartz (Fig. 14b).

MEASUREMENTS (in um). Two specimens: body length 1 1 1-1 14, breadth 79-82, depth 50,
diameter of aperture 3 1 .

REMARKS. There does not appear to be any prior descriptions of any similar compressed
species of Difflugia, and D. balcanica is considered to be distinct in having a leaf-like shape,
with an angular surface and a pointed aboral extremity.

DIFFLUGIIDAE FROM YUGOSLAVIA

361

Fig. 13 Difflugia wailesi: a, lateral view of typical specimen x 760; b, apertural view of a, note
the six indentations x470; c, lateral view of elongate specimen x 1 100; d, apertural view of; c, to
show circular aperture and surrounding collar x 720; e, detail of teeth on inner rim of circular
aperture x5100.

362

C. G. OGDEN & A. 2lVKOVIC

Fig. 14 Difflugia balcanica sp. nov.: a, view to illustrate general outline with aboral pro-
tuberance x570; b, apertural view x620; c, lateral view to show compression, note the
tapering at the apertural and aboral extremities x 460.

Difflugia bistrica sp. nov.

DESCRIPTION. The shell is ovoid or roughly circular, thin and laterally compressed (Fig. 15a
& b). It is composed of medium flattened pieces of quartz with smaller particles between to
give a smooth surface (Fig. 15d). Small areas of organic cement occur infrequently, and are
usually in the form of a network (Fig. 1 5e). The aperture is a regular oval and surrounded by
small particles (Fig. 1 5c).

MEASUREMENTS (in um). One specimen: body length 104, breadth 84, depth 54, diameter of
aperture 38.

REMARKS. Although this specimen has an encrustation of small debris, which is not part of
the shell matrix (see Fig. 15d), it is still possible to describe the surface as smooth. This
species is similar to D. balcanica in dimensions and degree of compression, but differs signifi-
cantly in having a rounded, smooth shell which is curved gently at the aboral extremity.
Notwithstanding that this description is based on a single specimen, it is still considered to
represent a distinct species and is so designated.

Difflugia dragana sp. nov.

DESCRIPTION. The shell is opaque, elongate ovoid, thick, tapering gradually from the
mid-body position to a gracefully curved aboral extremity and anteriorly to the suggestion of
a small apertural collar, it is laterally compressed (Figs 16a & b). Medium pieces of quartz
appear to make up most of the surface with smaller particles added. Only small strands of
organic cement have been seen (Fig. 16d) between these particles. The aperture is circular
and surrounded by mainly small particles of quartz (Fig. 16c).

MEASUREMENTS (in um). One specimen: body length 195, breadth 1 19, depth 96, diameter of
aperture 48.

DIFFLUGIDAE FROM YUGOSLAVIA

363

Fig. 15 Difflugia bistrica sp. nov.: a, lateral view to show regular, circular shape x 760; b, view to
illustrate lateral compression, note the gentle aboral curvature x 720; c, apertural view showing
oval-shaped aperture x 660; d, portion of shell surface to show flat particles overlaid with
extraneous debris x 2900; e, organic cement (arrowed) partially obscured by debris x 13000.

364

C. G. OGDEN & A. 2lVKOVIC

Fig. 16 Difflugia dragana sp. nov.: a, lateral view to illustrate the general outline x490; b, view
of lateral compression to show gradual curving at both extremities x 320; c, apertural view
x 400; d, part of shell surface with strands of organic cement (arrowed) x 9400.

REMARKS. This compressed specimen is similar to D. lingula Penard, 1911, D. avellana
Penard, 1890 and D. hiraethogii Ogden, 1983. It differs from D. lingula and D. avellana
which have pyriform shells, because of the narrow, elongate body which is almost cigar-
shaped in lateral view (Fig. 16b), and wide aperture. Although it is most similar to D.
hiraethogii, it lacks the distinct neck of this species and is again more elongate and not evenly
compressed. D. dragana is considered to be distinct in having an elongate, compressed shell
with a wide aperture.

DIFFLUGIDAE FROM YUGOSLAVIA

365

Fig. 17 Difflugia serbica sp. nov.: a, lateral view of specimen encrusted with extraneous debris
x680; b & c, additional specimens to illustrate the variations of tapering x310 & 240; d,
apertural view x420; e, view to show lateral compression x400; f, detail of organic cement
network x 21000.

366

C. G. OGDEN & A. 2IVKOVIC

ETYMOLOLGY. This species is named after Dragana Dorothea Zivkovic, who has been most
helpful in correcting the language shortcomings of both authors.

Difflugia serbica sp. nov.

DESCRIPTION. The shell is opaque, shaped like a spear-head, tapering evenly from the body
to the pointed aboral extremity and gradually, anteriorly towards the short apertural collar,
it is laterally compressed (Figs 1 7a-e). The body is composed mainly of medium to large
flattish pieces of quartz with a mixture of small to medium pieces at the aperture and aboral
extremity. Although the surface is usually smooth, two of the specimens are covered with a
layer of small particular debris which appears to have been added after the shell was con-
structed (Fig. 1 7e). The organic cement is not frequently seen but is in the form of a network,
the mesh being about 400 nm in diameter with walls 50 nm thick, each mesh being covered
(Fig. 1 70- The aperture is circular and usually surrounded by small particles (Fig. 1 7d).

Fig. 18 Difflugia serbica sp. nov. Diagrams of four specimens to show the variation in outline.

MEASUREMENTS (in um). Five specimens: body length 169-189, breadth 110-113, depth
68-79, diameter of aperture 31-41.

REMARKS. The dimensions of five specimens from the Yugoslavian sample were somewhat
larger: body length 180-280, breadth 1 10-160, depth 75-1 15 (only two measured), diameter
of aperture 40-70. Nevertheless, they demonstrate a similar variability in general shape and
structure (Fig. 18). This species is similar to D. soudanensis Gauthier-Lievre & Thomas
(1958) and D. kempyi Stepanek, 1953 in general dimensions, but both of these species have a
distinct apertural collar, are curved aborally and have a median pronounced spine or horn.
Furthermore, of these two species only D. soudanensis is compressed. Difflugia serbica is
considered to be distinct in having an irregular spear-shaped shell which is laterally
compressed, with the suggestion of a small apertural collar and usually pointed aborally.

Difflugia serrata sp. nov.
DESCRIPTION. The shell is transparent, ovoid, composed of small to medium flattish particles

DIFFLUGIDAE FROM YUGOSLAVIA

367

Fig. 19 Dijjlugia serrata sp. nov.: a, lateral view, note the serrated apertural margin x 1300; b,
apertural view x 930; c, portion of shell surface with organic cement (arrowed) x 9400.

of quartz arranged to give a smooth surface (Fig. 1 9a). Organic cement is seen as small
strands or as a smooth sheet, with regular perforations about 50 nm in diameter (Fig. 1 9c).
The aperture is circular with a slight irregular or serrated margin (Figs 19a & b).

MEASUREMENTS (in um). One specimen: body length 66, breadth 56, diameter of aperture 28.
REMARKS. This species is distinct from other ovoid species of similar dimensions, like D.

368

C. G. OGDEN & A. 2lVKOVIC

Fig. 20 Dijflugia styla sp. nov.: a, lateral view to illustrate the aboral spine and smooth surface

X 700; b, apertural view x 960.

Fig. 21 Difflugia elegans. Illustrations of four specimens, the typical constriction of the neck can

be seen in a.

minuta Rampi, 1950 and D. pristis Penard, 1902 which have recently been redescribed by
Ogden (1983), in having a thin smooth shell and a wide aperture. It is most similar to D.
pristis, but the more ovoid or rounded shell, with a large and serrated aperture serve to
distinguish D. serrata.

Difflugia styla sp. nov.

DESCRIPTION. The shell is transparent, ovoid with a distinct aboral spine (Fig. 20a). It is
composed of small to medium flattish pieces of quartz, and a network of organic cement is
often seen around the aperture as part of the shell matrix. Elsewhere on the surface the
organic cement is seen as strands between particles. The aperture is circular and surrounded
by smallish particles (Fig. 20b).

DIFFLUGIDAE FROM YUGOSLAVIA 369

MEASUREMENTS (in um). One specimen: body length 97, breadth 54, diameter of aperture 29.

REMARKS. This species is similar to D. elegans or D. bicornis (see p. 000) in having a single
aboral spine or horn. However, both of these latter species are described as having a rough,
irregular surface made of angular quartz particles and diatom frustules. In addition, D.
elegans has a slight constriction of the neck which gives the aperture a flared appearance
(Ogden, 1979), and it was found in the Yugoslavian portion of the sample to show these
features (Fig. 21). Although D. styla shares similar dimensions to D. serrata (see p. 000) the
presence of an aboral spine separates these species. D. styla is distinct in being elongate ovoid
with an aboral spine, and having a smooth shell composed of flat particles.

Genus CUCURBITELLA Penard, 1902

Cucurbitella vlasinensis sp. nov.

DESCRIPTION. The shell is brown or opaque, subcircular or ovoid, with a distinct apertural
collar (Fig. 22a). It is composed of a mixture of small to medium pieces of quartz to give a
rough surface, but arranged so that the outline is more or less regular. The particles are
packed close together (Fig. 220, with only small areas of organic cement visible. The cement
is in the form of a network whose mesh is covered by a smooth membrane (Fig. 22e). The
collar is trilobed and composed of small pieces of quartz arranged randomly (Fig. 22b). A
double thickness of particles strengthens the three tooth-like projections where they form a
dividing barrier with the inner apertural opening; these 'teeth' are usually well denned and
composed of small particles. Each lobe has a small recess or cavity so that the internal
opening is smaller than the external collar, the floor of these recesses appears as a con-
tinuation of the shell matrix (Fig. 22d). The apertural opening is trilobed in sequence with
the collar and lined with flattish pieces of quartz with smaller pieces filling the junctions (Fig.
22c).

MEASUREMENTS (in um). Forty-one specimens: body length 81-1 13, breadth 69-97, diameter
of collar 36-5 1 , depth of collar 9-16, diameter of aperture 1 9-35.

REMARKS. In a review of the genus Cucurbitella by Gauthier-Lievre & Thomas (1960) the
number of lobes surrounding the aperture was used to differentiate species into a number of
varieties and forms. More recently, Ogden (19806) considered that the three and four lobed
specimens of C. mespiliformis were otherwise identical in all but that feature, and should
therefore be designated as a single species until adequate morphological information was
available on the variability of lobe formation. Nevertheless, observations on the many speci-
mens of the present sample show that there is little or no variation in the number and shape
of the lobes. C. vlasinensis is similar to C. modesta Gauthier-Lievre & Thomas, 1960 and C.
modesta forma trilobata Gauthier-Lievre & Thomas, 1960. It differs from C. modesta, which
has four lobes, in that feature and general measurements, and from C. modesta forma
trilobata in having well-defined teeth, a more extensive inner lining to each lobe and in over-
all larger general dimensions.

An interesting ecological point to note is that C. modesta forma trilobata was reported
only from Morocco which has similar climatic conditions to the region of Yugoslavia
where the present samples were collected.

ETYMOLOGY. This species is named after the location where the samples were collected, Lake
Vlasina, and which, after a visit by both authors in 1 982, has become especially significant.

Genus PONTIGULAS1A Rhumbler, 1895

Pontigulasia bryophila Penard, 1902

DESCRIPTION. The shell is pyriform, tapering from the aperture to the slightly swollen
posterior third of the body (Fig. 23a). It has a rough surface composed of a mixture of quartz
particles with an occasional diatom frustule added. Organic cement is seen at the junctions

C. G. OGDEN & A. 2IVKOVIC

Fig. 22 Cucurbitella vlasinensis sp. nov.: a, lateral view x 830; b, apertural view x 540; c, view to
illustrate the arrangement of particles around the collar x 1200; d, detail of aperture to show
tooth-like projections and smaller internal opening x 1200; e, detail of organic cement
(arrowed) x 1 3000; f, portion of shell surface showing the close packing of particles x 1 500.

DIFFLUGIDAE FROM YUGOSLAVIA

371

Fig. 23 Pontigulasia bryophila: a, lateral view x 470; b, view inside external aperture to show the
internal aperture opening (arrowed), micrograph obtained by 'expanded contrast' facility
x4100; c, apertural view x760; d, detail of organic cement to illustrate the smaller irregular
network of each mesh enclosure x 29000.

between particles as a network. This network has a mesh about 600 nm in diameter
separated by walls 200 nm thick. Each enclosure has a smaller irregular network over its
surface (Fig. 23d). The external aperture is small, surrounded by small or medium particles
often arranged to give a serrated or tooth-like margin (Fig. 23c). The single, internal aperture
is roughly circular (Fig. 23b) and positioned about a quarter of the body length from the
external aperture.

MEASUREMENTS (in urn). See Table 2.

REMARKS. This species is similar in general appearance to Difflugia bryophila but may be
distinguished from it by the presence of an internal aperture and a different organic cement
pattern. The present specimens are similar in most respects to specimens of P. bryophila
found in England (C.G.O. pers. observ.) except for a difference in organic cement patterns.
This feature alone is not considered sufficient for specific recognition.

372

C. G. OGDEN & A. ZlVKOVIC

Pontigulasia montana sp. nov.

DESCRIPTION. The shell is pyriform, bluntly rounded aborally for one-third of its length and
usually tapering gradually from the widest point towards the aperture (Fig. 24a), although
sometimes there is a distinct constriction at the position of the internal aperture (Fig. 24c). It
is composed of a mixture of mainly medium to large pieces of quartz arranged to give a rough
surface. Organic cement is often seen as part of the shell matrix (Fig. 24d), in the form of an

Fig. 24 Pontigulasia montana sp. nov.: a, lateral view of specimen without neck constriction
x 730; b, apertural view with the internal aperture arrowed x 730; c, lateral view of specimen
with distinct neck constriction x430; d, portion of shell surface showing organic cement as part
of the shell matrix x4400; e, detail of organic cement network x 14000.

DIFFLUGIDAE FROM YUGOSLAVIA 373

open network with walls 200 nm thick and a mesh diameter of 400 nm (Fig. 24e). The
external aperture is roughly circular and surrounded by small or medium particles randomly
positioned to give it an irregular margin (Fig. 24b). The smaller, single, internal aperture is
also circular and surrounded by small particles overlaid with organic cement.

MEASUREMENTS (in um). See Table 3.
Table 3 Range of measurements (in um) of two species ofPontigulasia

Diameter

Length

Breadth

of external

ofinternal

(1)

(B)

aperture (da)

aperture

B/L

da/L

P. bryophila

99-146

52-66

18-21

11-14

0-52 + 0-05

0-15+0-03

P. montana

91-125

68-81

28-32

15-18

0-6910-07

0-28±0-03

REMARKS. The specimens described here are similar to Pontigulasia bryophila Penard, 1902,
but the latter species has a more streamlined, elongate shell, with smaller internal and
external openings, plus a distinct organic cement pattern. Comparison of the measurements
given in Table 3 emphasizes the difference in body and apertural size between these two
species, furthermore, P. bryophila appears to be the only previously described species of
Pontigulasia with a single internal aperture.

ETYMOLOGY. This species is named after the geographical topography surrounding Lake
Vlasina, which is mountainous (L. montana).

Summary

The information provided by this study extends our knowledge of the family Difflugiidae, in
particular the finding of compressed species of Difflugia. The scarcity of these forms is
perhaps highlighted by the review of African species in which Gauthier-Lievre & Thomas
(1958) list twelve compressed species, of these nine were new, out of a total of one hundred
and thirty-three. Thirty-three species of Difflugia are listed here of which thirteen are re-
described, including two former varieties of D. oblonga — namely D. lata and D. nodosa, six
new species are described — D. balcanica, D. bistrica, D. dragana, D. serbica, D. serrata and
D. styla the first four having compressed shells. In addition, two other new species are
described — Cucurbitella vlasinensis sp. nov. and Pontigulasia montana sp. nov.

It has been mentioned before (Ogden, 19806) that the size and shape of the aperture in
pyriform species of Difflugia is a relatively uniform character, but in ovoid specimens
appears more variable as shown here in the description of D. lismorensis.

Morfoloska studija nekih Difflugiidae iz Jugoslavije (Rhizopoda,

Protozoa)

REZIME

Podatke date u ovom radu prosiruju nasa znanja o familiji Difflugiidae, narocito u pogledu
otkrivanja pljosnatih vrsta Difflugia. Retkost ovih vrsta mozda se najbolje ogleda u radu o
africkim vrstama, Gauthier-Lievre i Thomas (1958), u kome je dat spisak od ukupno 133
vrsta; medju njima je dvanaest pljosnatih vrsta, od kojih je devet novih. Ovaj rad sadrzi
spisak od tridesettri vrste Difflugia, od kojih su trinaest ponovo opisane, ukljucujuci i dya
ranija varijeteta: D. oblonga, odnosno D. lata i D. nodosa, a opisano je i sest novih
vrsta — D. balcanica, D. bistrica, D. dragana, D. serbica, D. serrata i D. styla, od kojih prve

374 C. G. OGDEN & A. 2IVKOVIC

cetiri poseduju pljosnate ljusture. Opisane su i dve nove vrste — Cucurbitella vlasinensis sp.
nov. i Pontigulasia montana sp. nov.

U ranijim publikacijama ukazano je (Ogden, 19806) da su velicina i oblik pseudostoma u
piriformnim vrstama Difflugia relativno konstantna, medjutim, pojavljuje se veca vari-
jabilnost u ovoidnim uzorcima, kao sto je slucaj u D. lismorensis.

Prouceni materijal sakupljen je 9 septembra 1947. godine iz jedne bare sa prostrane
sfagnumske tresave na Vlasini (1200 m) koja je izgradnjom akumulacionogjezera izcezla.

References

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& 1 960. Le genre Cucurbitella Penard. Arch. Protistenk. 104 : 569-602.

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Manuscript accepted for publication 23 July 1982

British Museum (Natural History)

An Atlas of Freshwater Testate Amoebae

C. G. Ogden & R. H. Hedley

1980, Hardcovers, 222pp, £17.50 (£18.00 by post). Co-published by British Museum
(Natural History) and Oxford University Press.

The text is designed not only to enable biologists to identify species of testate
amoebae, but to serve as an introduction to students interested in the taxonomy
and biology of these freshwater protozoa. It will be of special interest to
protozoologists, ecplogists, limnologists, water treatment specialists and
micropalaeontologists interested in recent sediments.

British Museum (Natural History)
Publication Sales,
Cromwell Road,
London SW7 5BD.

Titles to be published in Volume 44

Observations on the systematics of the genus Difflugia in
Britain (Rhizopoda, Protozoa).
By Colin G. Ogden

Miscellanea

A review of the Euplotidae (Hypotrichida, Ciliophora).

By Colin Curds & Irene C. H. Wu

The Opthalmotilapia assemblage of cichlid fishes reconsidered.

By Peter Humphry Greenwood

Osteology, genitalia and relationships of the Acanthodactylus
(Reptilia: Lacertidae). By E. N. Arnold

Morphological studies on some Difflugiidae from Yugoslavia
(Rhizopoda, Protozoa).

By Colin G. Ogden & Andjelija Zivkovic

Printed by Henry Ling Ltd, Dorchester

BOUND

2 0 JUL 1988

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