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Phyiogeny and Paedomorphosi
African Family of Freshwater ^
(Gonorynchiformes: Kneriidae)

Terry Grande

October 31, 1994
Publication 1459

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FIELDIANA

Zoology

^JEW SERIES, NO. 78

Phylogeny and Paedomorphosis in an
African Family of Freshwater Fishes
[Gonorynchiformes: Kneriidae)

rerry Grande

Research Associate

Department of Geology

Field Museum of Natural History

Roosevelt Road at Lake Shore Drive

Chicago, Illinois 60605-2496

Assistant Professor
Department of Biology
Loyola University
5525 North Sheridan Road
Chicago, Illinois 60626

Accepted May 26, 1994
Published October 31, 1994
Publication 1459

PUBLISHED BY FIELD MUSEUM OF NATURAL HISTORY

© 1994 Field Museum of Natural History

ISSN 0015-0754

PRINTED IN THE UNITED STATES OF AMERICA

Table of Contents

Abstract 1

Introduction 1

Methods 2

Materials Examined 2

List of Abbreviations 4

Results and Systematic Descriptions 4

Unnamed Kneriid Subgroup A 5

Grasseichthys Gery, 1 964 6

Cromeria Boulenger, 1901 8

Unnamed Kneriid Subgroup B 13

Unnamed Kneriid Subgroup C 13

Parakneiua Poll, 1 965 13

Knerl\ Steindachner, 1 866 16

Discussion 17

Acknowledgments 19

Literature Cited 20

List of Illustrations

1 . Phylogenetic hypothesis of gonorynchi-
form relationships 3

2. Phylogenetic hypothesis of kneriid rela-
tionships showing two monophyletic
groups: Grasseichthys + Cromeria and
Parakneria + Kneria 5

3. Coronoid processes of Chanos chanos

and Kneria wittei 6

4. Skull of Grasseichthys gabonensis and
ventral skull of Chanos chanos 7

5. Anterior vertebrae and neural arches of
Parakneria tanzaniae 8

6. Skull, anterior vertebrae, and neural
arches of Cromeria nilotica 8

7. Specimen of Grasseichthys gabonensis

and Cromeria nilotica occidentalis 9

8. Lateral view of suspensorium of Gras-
seichthys gabonensis 10

9. Anterior vertebrae and neural arches of
Grasseichthys gabonensis 10

10. Skull of Cromeria nilotica 11

1 1 . Lateral view of suspensorium of Crome-
ria nilotica 11

12. Ventral gill arches of Parakneria tanza-
niae and Chanos cyprinella 12

13. Specimens of Parakneria tanzaniae and
Kneria wittei; specimen of K. wittei
showing opercular apparatus 13

14. Dorsal and ventral views of skull of
Parakneria tanzaniae 14

15. Lateral and medial views of suspensoria

of Parakneria tanzaniae 15

16. Dorsal and ventral views of skull of
Kneria wittei 17

17. Lateral and medial views of suspensoria

of Kneria wittei 18

18. Anterior vertebrae and neural arches of
Kneria wittei 19

List of Tables

Data matrix from which the phylogenetic
hypothesis for kneriid fishes was con-
structed 4

Meristic counts of representative sp)ecies
of Kneria, Parakneria, Cromeria, and
Grasseichthys for comparisons 9

f

[

Phylogeny and Paedomorphosis in an
African Family of Freshwater Fishes
(Gonorynchiformes: Kneriidae)

Terry Grande

i Abstract

The freshwater gonorynchiform family, Kneriidae, lives in west and central Africa and con-
tains some of the smallest known vertebrates. The extremely small size and paedomorphic
nature of some of these species pose an interesting theoretical problem for phylogenetic analyses.

The Kneriidae is defined as monophyletic in part by the presence of lateral extensions of the
mesethmoids and the articulation of the first neural arch with both the exoccipitals and su-
praoccipital. The family is frequently divided into two clades, one consisting of the genera
Cromeria and Grasseichthys, and the other consisting oi Parakneria and Kneria. Cromeria and
Grasseichthys are unusually small fish that mature at only 30 and 16 mm standard length,
respectively, whereas Parakneria and Kneria are substantially larger by the time they reach
maturity. Three characters supporting the Cromeria + Grasseichthys clade are the lack of scales,
incomplete cranial ossification, and the lack of median contact between the frontal bones.
Incongruent with those three characters is a peculiarly shaped vomer shared by Cromeria,
Parakneria, and Kneria. At first look, parsimony would seem to indicate that the Cromeria +
Grasseichthys group is monophyletic. The three characters supporting that group, however, are
problematic, because they all are either absence or reductive characters and could be the result
of paedomorphic developmental patterns. In contrast, the vomer character suggesting a Crome-
ria + Parakneria + Kneria group is neither a loss nor a reductive character. Additional non-
reductive characters are needed to better resolve the family interrelationships.

Introduction convenience. Gosline (1960) stated that "each

family within the Gonorynchoidei is so widely dif-

The teleostean order Gonorynchiformes is ferent that any relationship between them is dif-

geographically widespread, is morphologically di- ficult to comprehend" (p. 353).

verse, and has a fossil record dating back to the Not until Greenwood et al. (1966) reexamined

Early Cretaceous. For many years the order was gonorynchiform relationships was any significant

poorly defined and its monophyly in doubt (Gayet, progress made. They proposed the order Gono-

1986). Various gonorynchiform taxa have in the rynchiformes with two suborders: the Gonoryn-

past been included in the Salmoniformes, Clupeo- choidei (including Gonorynchidae) and the Cha-

morpha and Elopomorpha (Regan, 1929). Gosline noidei (including Chanidae, Kneriidae, and

(1960) recognized the suborder Gonorynchoidei Phractolaemidae). Kneriidae 5en5M Greenwood et

in which he included the Chanidae, Gonorynchi- al. (1966) included two tiny (probably paedo-

dae, and Kneriidae, but he grouped these gono- morphic) genera, Cromeria and Grasseichthys.

rynchoids within the Cypriniformes. Gosline Gonorynchiformes was diagnosed as having an

(1960) was not convinced of the monophyly of epibranchial organ, upper and lower intermuscu-

Gonorynchoidei and gave no diagnostic characters lar bones, a loosely articulated suspensorium, and

for the taxon. He simply used it as a group of one or more pairs of cephalic ribs. In 1970 Rosen

FIELDIANA: ZOOLOGY, N.S., NO. 78, OCTOBER 31, 1994, PP. 1-20 1

and Greenwood included the Gonorynchiformes
within the superorder Ostariophysi as the sister
group to the Otophysi (fishes possessing a Weber-
ian apparatus and including all non-gonorynchi-
form ostariophysans). Lenglet (1974) agreed that
the Gonorynchiformes and Otophysi are closely
related but considered Rosen and Greenwood's
(1970) findings to be premature. He considered
the interrelationships within the order uncertain,
and the placement of Cromeria and Grasseichthys
in the Gonorynchiformes problematic because of
their probable paedomorphic nature. Lenglet
(1974) found that Cromeria and Grasseichthys do
not share all the characters of the Gonorynchi-
formes and proposed that the two genera be placed
within a new suborder, Cromeroidei, on the basis
of a reduction in cranial osteology, lack of scales,
and lack of suprapreopercle. Roberts (1973) crit-
icized Rosen and Greenwood's (1970) classifica-
tion and stated that the inclusion of the Gonoryn-
chiformes within the Ostariophysi would render
the latter paraphyletic. But later. Fink and Fink
(1981) corroborated Rosen and Greenwood's
placement of the Gonorynchiformes within the
Ostariophysi and further diagnosed the order. Al-
though today few ichthyologists question the
monophyly of the group, many debate the rela-
tionships among its taxa. Howes (1 985), in a study
based on muscle characters, was unable to resolve
relationships of taxa within the order.

In a study of the phylogenetic interrelationships
of both Recent and fossil gonorynchiform fishes,
Grande (1992) confirmed the monophyly of the
order. This was based on several characters, in-
cluding the loss of the orbitosphenoid bone, a re-
duction and separation of the pterosphenoid bones,
a reduction of the parietals along with expansion
of the frontal bones posteriorly, an extension of
the supraorbital canal ending on the frontals in-
stead of the parietals, the loss of teeth on the fifth
ceratobranchial, lateral expansion of the first neu-
ral arch, the presence of a strong ascending process
of the parasphenoid that rises high and passes in
front of the prootics, the presence of cephalic ribs,
and the presence of an epibranchial organ. Grande
(1992) also showed that Chanos (a marine Indo-
Pacific form) is the sister group to a group con-
taining the Gonorynchidae plus an African fresh-
water clade consisting of the Phractolaemidae
{Phractolaemus) and the Kneriidae (Grasseich-
thys, Cromeria, Parakneria, Knerid) (Fig. 1).

This paper will focus on the phylogenetic inter-
relationships of the family Kneriidae. The Knerii-
dae has long been a systematically problematic

group. Myers (1938) suggested that Cromeria (a
monotypic genus) was only a larval stage of some
species of Kneria. Howes (1985) tentatively syn-
onymized Parakneria and Kneria, stating that
"characters separating the genera Kneria and
Parakneria appear to be ones of degree and on the
basis of synapomorphies of the skeleton and jaw
musculature the two genera should probably be
considered a single genus" (p. 299). The family is
thus in need of review.

Methods

Skeletal material was prepared using a modified
version of Dingerkus and Uhler's (1977) method
of clearing and double staining. Measurements and
meristic counts were taken from all specimens ex-
amined as outlined by Hubbs and Lagler (1949).
Cranial and postcranial osteological illustrations
were made using a Wild M5 or M8 dissecting mi-
croscope equipped with a camera lucida.

Comparative morphological data were analyzed
to assess the relationships among kneriid fishes by
means of phylogenetic analysis, or cladistics (Nel-
son & Platnick, 1981). Character polarity was de-
termined by outgroup comparison. Outgroups
chosen for this study included Chanos (a gener-
alized gonorynchiform), Phractolaemus (the hy-
pothesized sister group to the Kneriidae), and Op-
sariichthys (a generalized cypriniform).

Derived character information (character ma-
trix. Table 1 ) was processed using outgroup root-
ing, Deltran optimization, and the branch-and-
bound version of PAUP version 3.0 (Swofford,
1990). These data were also analyzed using the
Hennig 86 program to test the stability of my data
matrix and the reliability of PAUP. Characters
were optimized using a character description pro-
gram, D3, version 2, by Buckup (1991). This pro-
gram generates lists of character state transfor-
mations from the output produced by Hennig 86.

Materials Examined

Chanos chanos: 1 6 specimens (SL = 30-220 mm):
AMNH 87984 (cleared & stained); ansp 122260,
122264 (alcoholics); fmnh 971 10, 3981, 101 19
(cleared & stained).

Chanos cyprinella: 58 specimens (SL = 70-105

FIELDIANA: ZOOLOGY

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Gonorynchiformes

Fig. 1. Phylogenetic hypothesis of gonorynchiform relationships from Grande (1993), modified from Grande
(1992). The cladogram was generated using the 3.0 version of PAUP; consistency index equals 0.83. Daggers indicate
extinct taxa. Bars identify monophyletic groups.

mm): cas 03108-031 15, 05022-05075 (cleared

& stained, alcoholics).
Gonorynchus sp.: 6 specimens (SL = 20-24.5 mm):

CAS 60742, 60743 (cleared & stained).
Goncrynchns gonorynchus: 3 specimens (SL =201-

213 mm): amnh 96050 SD, 96053 SD, 96057

(dried skeletons).
Gonorynchus greyi: 7 specimens (SL = 86-120

mm): amnh 32973 (cleared & stained); su 2078 1 ,

31874, 09178 (cleared &. stained, alcoholics).
Gonorynchus mosleyi: 1 specimen (SL = 122): su

29239 (holotype).

Phractolaemus ansorgei: 12 specimens (SL = 64.4-
123.9 mm): ansp 71873-71875 (cleared &
stained, alcoholics); fmnh 63938 (cleared &
stained).

Grasseichthys gabonensis: 43 specimens (SL =
15.5-20 mm): ansp 103405 (paratypes); cas
38524 (alcoholics); usnm 199509 (alcoholics);
USNM 272934 (cleared &, stained); usnm 1 9959 1
(paratypes, cleared & stained); su 63379 (alco-
holics); T 73-02-P-264-268 (cleared &. stained).

Cromeria nilotica: 2 specimens (SL = 23.2-25.6
mm): t 141098-099 (cleared & stained).

GRANDE: PHYLOGENY AND PAEDOMORPHOSIS IN KNERIIDAE

Table 1 . Data matrix from which the phylogenetic hypothesis for kneriid fishes was constructed.*

Characters

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

Grasseichthys

1

1

1

1

1

1

1

1

1

1

0

0

0

0

0

0

0

0

Cromeria

1

1

1

1

1

1

0

0

0

0

1

1

0

0

0

0

0

0

Parakneria

1

1

1

0

0

0

0

0

0

0

0

1

1

1

1

1

0

0

Kneria

1

1

1

0

0

0

0

0

0

0

0

1

1

1

1

0

1

1

Chanos

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Phractolaemus

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Opsariichthys

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

* 0 = primitive condition; 1 = derived condition.

Cromeria nilotica occidentalis: 12 specimens (SL

= 24-34.5 mm): su 54641 (cleared & stained);

BMNH 1 1.14:124-128 (cleared & stained).
Parakneria tanzaniae: 3 specimens (SL = 43.7-

49 mm): bmnh 10.21:163-165 (cleared &

stained).
Parakneria malaissei: 1 specimen (SL =57.6 mm):

T 164685 (male paratype, cleared & stained).
Kneria sp.: 5 specimens (SL = 5 1 .2-53.5 mm): CAS

16 1 50 (cleared & stained); usnm 272929 (cleared

& stained).
Kneria articulata: 5 specimens (SL = 44.9-47.8

mm): bmnh 5.2:8-10 (cleared & stained); usnm

257091 (cleared & stained).
Kneria katangae: 3 specimens (SL = 34.4-35.1

mm): bmnh 1976.10.20:116-118 (cleared &

stained, alcoholic).
Kneria wittei: 7 specimens (SL = 47.9-55.6 mm):

FMNH 63939 (alcoholics); t 79-0 l-P-5 16-521

(cleared & stained).
Opsariichthys bidens: 2 specimens (SL = 52.5-

67.1 mm): su 68907 (cleared &. stained).

For additional gonorynchiform and euteleos-
tean material examined and used for the phylo-
genetic analysis of the order of Gonorynchiformes,
see Grande (1992).

epo, epioccipital; exo, exoccipital; fr, frontal; hb 1 ,
hypobranchial 1; hb2, hypobranchial 2; hb3, hy-
pobranchial 3; hh, hypohyal; hm, hyomandibula;
lac, lacrimal; lat eth, lateral ethmoid; max, max-
illa; mes, mesopterygoid (= entopterygoid); meth,
mesethmoid; mpt, metapterygoid; n, nasal; na,
neural arch; op, opercle; pa, parietal; pal, palatine;
pmx, premaxilla; pop, preopercle; prot, prootic;
psph, parasphenoid; pto, pterotic; pts, pterosphe-
noid; q, quadrate; rat, retroarticular; rb, pleural
lib; SL, standard length (taken from the tip of the
snout to the posterior margin of the hypural); sn,
supraneural; so, supraorbital; soc, supraoccipital;
sop, subopercle; sph, sphenotic; sym, symplectic;
vert, vertebrae; vo, vomer.

Institutional— AMNH, American Museum of
Natural History, New York; bmnh, British Mu-
seum (Natural History), London; cas, California
Academy of Sciences, San Francisco; fmnh. Field
Museum of Natural History, Chicago; su, Cali-
fornia Academy of Sciences, Stanford Collection,
San Francisco; t, Musee Royal de L'Afrique Cen-
tral,Tervuren; USNM, Smithsonian Institution,
Washington, D.C.

Results and Systematic Descriptions

List of Abbreviations

Anatomical— aa, anguloarticular (terminology
from Nelson, 1973); bbl, basibranchial 1; bb2,
basibranchial 2; bb4, basibranchial 4; bb5, basi-
branchial 5; bh, basihyal; boc, basioccipital; cbl,
ceratobranchial 1 ; cb2, ceratobranchial 2; cb3, cer-
atobranchial 3; cb4, ceratobranchial 4; cb5, cera-
tobranchial 5; cha, anterior ceratohyal; chp, pos-
terior ceratohyal; crb, cephalic rib; dent, dentary;

One tree (Fig. 2) was found with a consistency
index of 0.83. The analysis indicates that the Kne-
riidae forms of monophyletic group consisting of
two clades. One clade consists of the genera Gras-
seichthys and Cromeria as sister taxa, and the other
clade consists of Kneria and Parakneria. A char-
acter conflict exists, however, in that Cromeria
shares with the Parakneria + Kneria clade a very
distinctive vomer morphology (character 1 2). This
character is therefore incongruent with the char-
acters uniting Cromeria with Grasseichthys. This

FIELDIANA: ZOOLOGY

4 5 6

1 2 3
I I I

7 8 9 10
I I I I

11

1.3 14 1j
■ I I

B

16

1^

'Phractolaemus

'Grasseichthys

'Cromeria

•Parakneria

Kneria

Fig. 2. Phylogenetic hypothesis of kneriid relationships showing two monophyletic groups: Grasseichthys +
Cromeria and Parakneria + Kneria. Character 1 2 is shared by Cromeria, Parakneria, and Kneria and is incongruent
with the characters uniting Grasseichthys with Cromeria.

character conflict will be addressed in the Discus-
sion section.

Ostariophysi Sagemehl, 1885 {sensu Fink & Fink,
1981)

Gonorynchiformes Berg, 1940 {sensu Rosen &
Greenwood, 1970)

Kneriidae Steindachner, 1866 (sensu Rosen &
Greenwood, 1970)

Four monophyletic genera compose this family:
Kneria, Grasseichthys, Cromeria, and Parakneria.
They are all small fishes ranging in size from 20
to 60 mm SL, known only from freshwater rivers
and river basins of west and central Africa (Poll,
1933). Members of Kneriidae exhibit several in-
teresting morphological specializations (to be dis-
cussed) thought by several researchers to be eco-
logical adaptations (Thys van den Audenaerde,
1961). The Kneriidae, unlike other gonorynchi-
form families, have no known fossil record.

Members of the family Kneriidae are diagnosed
by the following synapomorphies:

(1) The angular forms a major component of the
coronoid process. In Chanos and Phractolae-
mus, the dentary forms the coronoid process
(Fig. 3).

(2) Lateral wing-like extensions on the meseth-

moids. These extensions also support a series
of nodular rostral processes (Fig. 4 A). In other
gonorynchiforms, there are no processes on
the mesethmoids, and the mesethmoids are
small with no extensions (Fig. 4B).
(3) Articulation between the first neural arch and
the exoccipitals and supraoccipital (Figs. 5, 6,
and 9). In Grasseichthys, Cromeria, and Para-
kneria, the first neural arch forms an antero-
dorsal extension that articulates with the back
of the skull. In other gonorynchiforms, the first
neural arch abuts only the exoccipitals and
forms no extension.

Unnamed Kneriid Subgroup A

Monophyly of the Grasseichthys + Cromeria
clade is indicated by the following characters:

(4) Absence of scales on the body. In all other
gonorynchiform taxa, scales are present on the
body or in some cases also covering the head
(i.e., Gonorynchus). Interestingly, Gonoryn-
chus specimens less than 25 mm SL are also
devoid of scales (cas 60742, 60743). This
character is therefore problematic and indi-
cates that the lack of scales in Grasseichthys
and Cromeria may be the result of delayed or
arrested development (i.e., paedomorphosis).

(5) Absence of suprapreopercle bones. These bones
are found in most other gonorynchiforms (with
the exception of the Gonorynchidae) and most

GRANDE: PHYLOGENY AND PAEDOMORPHOSIS IN KNERIIDAE

Fig. 3. Coronoid processes (arrow) of (A) Chanos chanos, fmnh 971 10 (SL = 76.2 mm), and (B) Kneria wittei,
T 79-01-P-5 16 (SL = 54.3 mm). Kneriids are diagnosed by a reduction in the size of the dentary and an enlargement
of the anguloarticular.

otophysans. It is hypothesized that the loss of
these bones occurred independently in the
Gonorynchidae, Grasseichthys and Cromeria,
and that the presence of such bones is most
likely an ostariophysan character.
(6) The paired frontals are widely separated in the
adults and do not contact each other medially.
The frontal bones run along the sides of the
skull separated by a protruding brain covered
only by connective tissue and skin (Fig. 6).
This condition does not occur in any other
adult gonorynchiform. In all other gonoryn-
chiforms, the skull is well ossified on the dorsal
surface and the frontals either meet along the
midline (i.e., Chanos) or are laid down as one
median element (i.e., Gonorynchns). Once
again, the separated frontal bones seen in
Grasseichthys and Cromeria may be the result
of an incomplete ossification process. Early
ontogenetic stages observed in Chanos also
show a separation of the frontals, and then
later in development the bones articulate with
each other along the dorsal midline of the skull.
This character uniting Grasseichthys with Cro-
meria in all probability does not reflect their
true phylogenetic relationships but is really the
result of delayed development.

Grasseichthys Gery, 1964

The genus Grasseichthys is a monotypic genus
consisting of only G. gabonensis Gery, 1964 (Fig.
7A). Although not much is known about its ecol-
ogy, life history, and behavior, Gery (1964) re-
ported that Grasseichthys is found in freshwater
streams deep in the forests of Gabon and central
Zaire. Grasseichthys gabonensis is the only species
within the Gonorynchiformes without an epibran-
chial organ. Gut content analysis indicates that
Grasseichthys feeds on small insects and is prob-
ably not an epiphytic feeder like all other gono-
rynchiforms.

Grasseichthys reaches an adult length of only 20
mm SL. Individuals are mature at only 16-18 mm
SL. The body is elongate, compressed, and semi-
translucent. Scales are absent and the myomeres
are clearly visible. The mouth is small and ter-
minal. The dorsal fin is short and inserts behind
the middle of the body (predorsal length equals
56% of SL). The pelvic fins are abdominal. The
pectoral base and girdle are attached to the head,
and posttemporals are absent. The caudal fin is
rounded, and the caudal peduncle is three times
longer than high. The number of dorsal fin rays is
reduced to 5 principal rays, pelvic fin rays 5-6,

FIELDIANA: ZOOLOGY

Fig. 4. A. Skull of Grasseichthys gabonensis, t 73-02-P-264 (SL = 18.9 mm) showing laterally extended meseth-
moid extensions with nodular processes. B. Ventral skull of Chanos chanos, fmnh 971 10 (SL = 76.2 mm) showing
a reduced mesethmoid devoid of lateral processes. Anterior to left.

pectoral fin rays 4-5, and anal fin rays 5-6. The
number of vertebrae is 36-37, and the number of
branchiostegal rays is reduced to 2 (Table 2).

Cranium and Jaw Elements— The entire cra-
nium of Grasseichthys is poorly ossified (Fig. 4).
The frontals are separated, and it is therefore pos-
sible to look through the skull and examine the
ventral elements and at the same time examine
the dorsal skull bones. The mesethmoid possesses
laterally extended wings, which are diagnostic for
the family Kneriidae. The lateral ethmoids are ex-
tended, as in all African forms, including Phrac-
tolaemus. The vomer and parasphenoid are straight
and the parasphenoid forks posteriorly as it meets
the basioccipital. The supraoccipital and parietals
are small in size, but the exoccipitals are greatly

enlarged both posteriorly and laterally, accom-
modating the large occipital region of the brain.

The suspensorium and cheekbones are poorly
ossified (Fig. 8.) Both the ectopterygoid and met-
apterygoid bones are absent. The symplectic (re-
ported by Gery, 1964, as missing) is slender and
elongated, unlike that found in other kneriids.

Anterior Vertebrae and Associated Struc-
tures—The first vertebra (Fig. 9) is approximately
one-third the size of the rest, and its neural arch
extends and articulates with both the exoccipitals
and the supraoccipital. A hook-like process ex-
tends posteriorly from the ventral side of the sec-
ond vertebra. The second neural arch is expanded
both dorsally and posteriorly. All neural arches
abut their posteriorly positioned vertebra. Only
those supraneurals associated with the second and

GRANDE: PHYLOGENY AND PAEDOMORPHOSIS IN KNERIIDAE

Fig. 5. Anterior vertebrae and neural arches o{ Parakneria tanzaniae, bmnh 10.21:163 (SL = 43.7 mm). Anterior
to right.

third arches are present. The first pleural rib is
fused with the third vertebra, and there are no
intermuscular bones, including cephalic ribs.

Grasseichthys is diagnosed by the following apo-
morphies:

(9) Absence of metapterygoids. All other gono-
rynchiforms have metapterygoids.
(10) Absence of intermuscular bones, including
cephalic ribs. This is the only gonorynchi-
form without intermuscular bones.

(7) The symplectic is elongated, proportionally
twice that found in other kneriids.

(8) Absence of the ectopterygoids. Ectopterygoid
bones are found in all other gonorynchi-
forms.

Cromeria Boulenger, 1901

This paedomorphic gonorynchiform genus con-
sists of only one species, C nilotica. Two subspe-

^^^

Fig. 6. Skull, anterior vertebrae, and neural arches oi Cromeria nilotica, t 141098 (SL = 23.2 mm) showing the
separated frontal bones and a first neural arch that articulates with both the exoccipitals and supraoccipital. Anterior
to left.

FIELDIANA: ZOOLOGY

cies (Cromeria n. nilotica Boulenger, 1901, and
Cromeria n. occidentalis Daget, 1954) have been
described based on minor meristic count differ-
ences and differences in geographic distributions.
Cromeria nilotica reaches an adult length of about
30-35 mm and is mature at about 27 mm. It is
an elongate fish (Fig. 7B) with the body com-
pressed and scaleless. The eyes are very large (8%
of head length) and the otic capsule is enlarged.
The mouth is small and ventrally positioned. The
number of branchiostegal rays is reduced to 3. The
vertebrae are small and delicate and range in num-
ber from 42 to 43. The number of principal dorsal
fin rays is 7; anal fin rays, 5; pectoral fin rays, 9;
and pelvic fin rays, 7 (Table 2).

Not much is known about the ecology oi Crome-
ria. Gery (1964) reported that Cromeria is found
in tributaries near sandy riverbanks of the Nile
and Niger rivers (north of Grasseichthys' habitat).
Roberts (1972) reported that Cromeria spends
much of its time buried in the sand.

Cranial and Jaw Elements— Figure 10 illus-
trates both the dorsal and ventral skull bones in
Cromeria. This view is possible because of the
expanded frontals and the lack of ossification above
a much enlarged brain, a condition also found in

Fig. 7. A. Specimen of Grasseichthys gabonensis, t
73-02-P-265 (SL = 20 mm). B. Specimen of Cromeria
nilotica occidentalis, bmnh 11.14:124 (SL = 35 mm).
Scale bar = 10 mm.

Grasseichthys. The anterior cranial bones are re-
duced in size and poorly ossified. The vomer ex-
tends beyond the mesethmoid complex and is di-
rected ventrally (as opposed to horizontally as in
Grasseichthys). The lateral ethmoids are extended
anteriorly and are comparatively longer than those
of Grasseichthys. The parasphenoid is a thick bone
that extends to the posterior margin of the exoc-
cipitals and does not fork at its posterior end as it

Table 2. Meristic counts of representative species of Kneria, Parakneria, Cromeria, and Grasseichthys for com-
parisons. See text for discussions. Ranges in text are wider, based on additional specimens.

Total

Dorsal

Anal

Pectoral

Pelvic

vertebrae

fin rays

fin rays

fin rays

fin rays

Kneria katangae

BMNH 10.20:116

41

ii,9

ii 8 (6 branched)

11

10 (9 branched)

BMNH 10.20:117

41

ii,9

ii 8 (6 branched)

11

8 (7 branched)

Kneria sp.

USNM 272929a

41

ii,8

ii 8 (6 branched)

14

8 (7 branched)

USNM 272929b , ,., .

41

ii, 8

ii 8 (6 branched)

14

8 (7 branched)

: Kneria wittei

T79-01-P-516

42

u, 8

ii 8 (6 branched)

16

8 (7 branched)

T79-01-P-517

41

ii, 8

ii 8 (6 branched)

16

8 (7 branched)

Parakneria malaissei

T 164685

42

ii, 8

ii 7 (5 branched)

15

9 (8 branched)

Parakneria tanzaniae

BMNH 10.21:163

43

ii, 8

ii 7 (5 branched)

14

9 (8 branched)

BMNH 10.21:164

43

ii,8

ii 7 (5 branched)

14

9 (8 branched)

Cromeria nilotica

T 141098

42

i. 7

i 5 (4 branched)

9

7 (5 branched)

T 141099

42

i, 7

i 5 (4 branched)

9

7 (5 branched)

BMNH 11.14:124

43

i, 7

i 5 (4 branched)

9

' 7 (5 branched)

Grasseichthys gabonensis

T 73-02-P-264

36

i, 5

i 5 (4 branched)

5

6 (5 branched)

T 73-02-P-265

36

i, 5

i 5 (4 branched)

4

—

GRANDE: PHYLOGENY AND PAEDOMORPHOSIS IN KNERIIDAE

dent

Fig. 8. Lateral view of suspensorium oi Grasseichthys gabonensis, t 73-02-P-264 (SL = 18.9 mm). Anterior to
right. Light stippling indicates bone.

Fig. 9. Anterior vertebrae and neural arches of Grasseichthys gabonensis, t 73-02-P-264 (SL = 1 8.9 mm). Ante-
rior to right.

10

FIELDIANA: ZOOLOGY

lateth

Fig. 10. Skull of Cromeria nilotica, t 141098 (SL = 23.2 mm). Anterior to left.

does in Grasseichthys. The supraoccipital is greatly
enlarged while the parietals are hardly noticeable.
The exoccipitals are enlarged both dorsally and
anteriorly and do not border the foramen magnum
dorsally. The foramen magnum is therefore bor-
dered only by the large supraoccipital above and
the small basioccipital below.

The suspensorium and jaw bones (Fig. 1 1) are
considerably more ossified than in Grasseichthys
but are still quite delicate, showing size reductions
in all bones except possibly the hyomandibula.
The quadrate has a very distinctive shape, with
an elongated forked posterior process. There is no
symplectic.

Anterior Vertebrae and Associated Ele-
ments—The anteriormost vertebrae in Cromeria
are small and delicate (Fig. 6). The first neural arch
articulates with both the exoccipitals and the su-
praoccipital. All subsequent neural arches abut each
other dorsally and ventrally. There are no supra-
neurals, and there is no evidence to suggest that
they have fused with their corresponding neural
arches. A slender cephalic rib is present bilaterally,
extending from the exoccipitals to the cleithra. The
first pleural rib, although more robust than the
others, is slender and fused to the third vertebra.

Cromeria is diagnosed by the following apo-
morphy:

mes + mpt

pmx

Fig. 11. Lateral view of suspensorium of Cromeria nilotica, t 141098 (SL = 23.2). Anterior to left. Dark stippling
indicates cartilage; light stippling indicates bone.

GRANDE: PHYLOGENY AND PAEDOMORPHOSIS IN KNERIIDAE

11

12

HELDIANA: ZOOLOGY

(11) The presence of a distinctively shaped quad-
rate with an elongated forked posterior pro-
cess (Fig. 1 1). In other gonorynchiforms this
process is not present.

Unnamed Kneriid Subgroup B

The monophyly of a Parakneria + Kneria clade
is indicated by the following:

(13) The presence of ossified fourth and fifth bas-
ibranchials that lie between the enlarged cer-

Patobranchials (Fig. 1 2 A). In other gonoryn-
chiforms, the fourth and fifth basibranchials
are formed in cartilage (Fig. 1 2B).

(14) The presence of six infraorbital bones. Other
gonorynchiforms have five.

(15) Absence of parietals. In all other gonoryn-
chiforms, the parietals (although reduced in

\ —

Unnamed Kneriid Subgroup C

The monophyly of a Cromeria + Parakneria +
Kneria clade is indicated by the following synapo-
morphy:

( 1 2) Rostral extension and ventral inclination of
the vomer. In these fish, the anterior part of
the vomer is curved and directed ventrally.
In other gonorynchiforms, the vomer is
straight {Chanos, Grasseichthys, Gonorynchi-
dae) or curved dorsally (Phractolaemus). This
character is most likely unique among eute-
leosts. A character conflict therefore exists
between those characters uniting Cromeria
with Grasseichthys and this character uniting
Cromeria with the Kneria + Parakneria clade.

Parakneria Poll, 1965

These small African gonorynchiforms reach an
adult length of about 60 mm (Fig. 1 3 A). The body
is slender (body depth 12.6% of SL), the head is
small (about 14% of SL), the eyes are positioned
dorsolaterally, and the mouth is ventral. Scales

Fig. 13. A. Specimen of Parakneria tanzaniae, bmnh
10.21:165 (SL = 51 mm). B. Specimen oi Kneria wittei,
T 79-01-P-517 (SL = 62 mm). C. Specimen of Kneria
wittei, T 79-01-P-517 (SL = 62 mm) showing the oper-
cular apparatus. Scale bar = 10 mm.

cover the postcranial body. The number of bran-
chiostegal rays is reduced to 3. The number of
vertebrae ranges from 42 to 43; principal dorsal
fin rays, 8-9; pectoral fin rays, 14-15; pelvic rays,
9-10; and anal rays, 7 (Table 2).

Ten species of Parakneria have been described
from rivers in Rhodesia, Mozambique, Angola,
and the Congo Basin. Parakneria inhabits slow-
moving pools with muddy bottoms as well as fast-
moving streams with waterfalls (Jubb & Bell-Cross,
1974; Penrith, 1973). Parakneria is believed to be
an epiphytic feeder because of a developed epi-
branchial organ. Grande (1992) aligned Para-
kneria and Kneria as sister taxa (based on osteo-
logical characters), although Howes (1985) could
not distinguish them on the basis of myological
characters. The type species is Parakneria damasi
Poll, 1965.

Fig. 12. A. Ventral gill arches of Parakneria tanzaniae, bmnh 10.21:163 (SL = 43.7 mm) showing the ossification
of basibranchials 4 and 5. Cartilage is not drawn. B. Ventral gill arches of Chanos cyprinella, CAS 05022 (SL =101
mm) showing cartilaginous basibranchials 4 and 5. Anterior to left.

GRANDE: PHYLOGENY AND PAEDOMORPHOSIS IN KNERIIDAE

13

pmx

Fig. 14. Dorsal view (A) and ventral view (B) of skull of Parakneria tanzaniae, bmnh 10.21:163 (SL = 43.7 mm).
Anterior to left. Dashed lines indicate sensory canals.

Cranium and Jaw Elements— The morpho-
logical descriptions presented for the genus Para-
kneria are based on examinations of cleared and
stained specimens of P. tanzaniae Sind P. malaissei
and on Lenglet's ( 1 974) detailed osteological study
of P. thysi. The vomer in Parakneria (Fig. 1 4 A)
extends beyond the butterfly-shaped mesethmoid
and, as in Cromeria, is directed ventrally. The
lateral ethmoids extend anteriorly to the anterior
margin of the vomer. The lacrimals are elongated

and are at least twice as long as those of Kneria
(character 16). The frontals extend posteriorly to
the pterotics, which are larger and more rounded
than those of Kneria. Parietals are absent in Par-
akneria, so the pterotics border the triangularly
shaped supraoccipital instead of the parietals. A
supraoccipital crest is present but is not forked as
in Kneria. The exoccipitals are moderate in size
(not as disproportionally large as in Grasseichthys
and Cromeria) and do not border the foramen
magnum from above. On the ventral surface of

14

FIELDIANA: ZOOLOGY

Fig. 15. Suspensoria o{ Parakneria tanzaniae, bmnh 10.21:163 (SL = 43.7). A, lateral view; B, medial view.
Anterior to left.

the skull (Fig. 14B), the parasphenoid is a massive
bone that terminates in a point at the anterior end
of the basioccipital. The basioccipital is rectan-
gularly shaped and squat in comparison to Kneria.
Among the interesting osteological features of
this genus is the presence of large but thin maxilla
and premaxilla bones (Figs. 1 5 A and B). The pre-
maxilla overlaps the maxilla and completely ex-
cludes it from the gape. The ectopterygoid is re-
duced in size and borders the quadrate anteriorly.
The symplectic, in comparison to that of Gras-
seichthys, is greatly reduced in size (almost one-
half smaller). The opercular border is partially
sealed to the body wall, forming only a small pas-
sageway for water to exit the buccal cavity. The
extensions of the preopercle forming the height
and length of the bone (Fig. 1 5 A) are straight and

form a right angle where they meet posteriorly.
The preopercle is rounded in Kneria, and its ex-
tensions are of equal length. The subopercle has a
prominent ascending process that rises dorsal to
the level of the interopercle. One suprapreopercle
is present in this genus and serves only as a sensory
canal.

Anterior Vertebrae and Associated Ele-
ments—The neural arch of the first vertebra is
expanded and enlarged. Two dorsal processes ex-
tend from this arch and articulate with the exoc-
cipitals and supraoccipital (Fig. 5). The second
neural arch is without a neural spine. One single
autogenous supraneural is present posterior to
neural arch 2; no other supraneurals are present.
The first pleural rib is expanded and fused with
its vertebra. One large blade-like cephalic rib (Fig.

GRANDE: PHYLOGENY AND PAEDOMORPHOSIS IN KNERIIDAE

15

14 A) extends from the exoccipital to the cleithrum
on either side.

Ventral Gill Arches— In Parakneria (as well
as Kneria), both basibranchials 4 and 5 are ossified
(Fig. 1 2A). In more generalized gonorynchiforms
(i.e., Gonorynchus and Phractolaemus), only basi-
branchials 2 and 3 are ossified; the others are car-
tilaginous.

Parakneria is diagnosed by the following syn-
apomorphy:

( 1 6) Elongated lacrimal bone, proportionally three
times the lacrimal length oi Kneria (Fig. 14 A).

Kneria Steindachner, 1866
(Xenopomatichthys Pellegrin, 1905,
Is a Junior Synonym)

Kneria reaches an adult size of about 55 mm
(Fig. 13B). It has a deeper body than its sister
taxon, Parakneria (15% of SL in Kneria as op-
posed to 1 3% of SL in Parakneria). The head is
shorter than Parakneria's, the eyes are lateral, and
the mouth is almost terminal. There are three
branchiostegal rays. The number of vertebrae
ranges from 41 to 46. The number of dorsal fin
rays is 9; pectoral fin rays, 1 1-14; pelvic rays, 8;
and anal fin rays, 8 (Table 2).

Fourteen species of Kneria have been described
from the Congo Basin and Angola. Kneria con-
stitutes the most specious genus within the order
Gonorynchiformes. Its habitat is very similar to
that of Parakneria, as it inhabits quiet forest pools
as well as fast-flowing waters (Howes, 1985). Kne-
ria, like most other gonorynchiforms, is an epi-
phytic feeder (Roberts, 1972). The type species is
Kneria angolensis Steindachner, 1866.

Cranium and Jaw Elements— Descriptions of
Kneria are based on examinations of Kneria sp.,
K. autriculata and K. wittei. The head of Kneria
is stout and not as elongate as Parakneria. The
vomer is directed ventrally and extends beyond
the anterior margin of the mesethmoid (Figs. 16A
and B). The lateral ethmoids extend anteriorly, but
they are not as long as in Parakneria. There are
no parietals, and the pterotics are elongated pos-
teriorly and separated by a large supraoccipital.
The supraoccipital is extended laterally, and the
supraoccipital crest is forked, unlike the crest of
Parakneria. The exoccipitals are considerably
larger in Kneria than in Parakneria. The para-
sphenoid runs along the ventral side of the cra-
nium and ends at the anterior margin of the ba-

sioccipital. One large foramen is positioned almost
in the center of the parasphenoid. Its function is
yet to be determined.

In Kneria, the premaxilla and the maxilla are
not as large as in Parakneria (Figs. 17A and B).
The ectopterygoid is almost jug-shaped, larger, and
more rounded than in Parakneria. The symplectic,
like that of Parakneria, is very small. The height
of the preopercle equals its length (in Parakneria,
the preopercle is longer than it is high), and the
interopercle appears more robust and massive than
in Parakneria. The opercular bone is rounded and
supports an opercular apparatus in males. The
subopercle is small, without an ascending process
as in Parakneria. Two suprapreopercular bones
are present (compared to one in Parakneria) but
are reduced to canals.

Anterior Vertebrae and Assocl\ted Ele-
ments—The anterior part of the vertebral column
of Kneria differs markedly from that of Parakneria
(Figs. 5 and 1 8). The anterior vertebrae are very
reduced in size and the neural arches are massive.
The first neural arch abuts both the exoccipitals
as well as the supraoccipital. There is, however,
no anterior process extending from the arch and
attaching to the skull as in Parakneria. There are
no autogenous supraneurals, although the second
supraneural is fused with the second neural arch.
One large forked cephalic rib is present. According
to Greenwood et al. (1966), this large rib is a fusion
of two smaller ones. Kneria differs from Para-
kneria in the presence of enlarged and expanded
epipleural ribs or intermuscular bones. These in-
termuscular bones branch oflffrom the pleural ribs
or from ventral processes of the first and second
vertebrae. These intermuscular bones extend lat-
erally and attach to the body wall by ligaments.
The most anterior six ribs are the most modified
and massive. Intermuscular bones of this nature
are not found in any other gonorynchiform, and
their presence distinguishes Kneria from Para-
kneria.

Kneria is diagnosed by the following synapo-
morphies:

(17) The external opercular region in males is
greatly modified, with a sucker-like appara-
tus directly on the opercle (Fig. 13). It has
been assumed that this apparatus is used dur-
ing breeding (Lenglet, 1974), even though
virtually nothing is known about the fish's
life history. The histological structure of this
apparatus is now under investigation (Gran-
de & Jones, in prep.). It is not known whether

16

FIELDIANA: ZOOLOGY

pmx

Fig. 16. Skull oiKneria wittei, t 79-01-P-516 (SL = 54.3 mm). A, dorsal view; B, ventral view. Anterior to left.

the males are bom with an opercular appa-
ratus or it develops at maturity. In any event,
no other gonorynchiform exhibits this oper-
cular modification.
(18) The anterior epipleural ribs are greatly mod-
ified and enlarged (Fig. 18). These ribs are
attached to the body walls. In no other gon-
orynchiform, male or female, are these ribs
expanded in this way.

Discussion

The phylogenetic study presented here clearly
shows that the family Kneriidae is monophyletic
and belongs to the order Gonorynchiformes, su-
perorder Ostariophysi. To exclude the genera Cro-
meria and Grasseichthys from the Kneriidae would
render the family paraphyletic. Contrary to Howes
(1985), Kneria exhibits two very interesting apo-

GRANDE: PHYLOGENY AND PAEDOMORPHOSIS IN KNERIIDAE

17

Fig. 17. Suspensoria of Kneria wittei, t 79-01-5 16 (SL = 54.3 mm). A, lateral view; B, medial view. Anterior to
left.

morphies that diagnose it as distinct among gon-
orynchiforms. These are the modified epipleural
ribs that attach to the body wall and the sucker-
like opercular apparatus found in males. These
characters plus differences in cranial and postcra-
nial morphology show that the genera Kneria and
Parakneria are diagnosable taxa and should not
be synonymized.

The relationship ofCromeria to the other kneri-
ids is problematic. A character conflict exists be-

tween the characters uniting Cromeria with Gras-
seichthys (i.e., loss of scales, reduction in cranial
ossification, and separated frontals) and the char-
acter that unites Cromeria with Kneria and Para-
kneria (ventral inclination of the vomer). Both
Cromeria and Grasseichthys are tiny-bodied forms,
and the characters that unite them are all loss or
reductive characters. Such characters are likely to
be the result of paedomorphic development in spe-
cies as small as these. Ontogenetic stages examined

18

FIELDIANA: ZOOLOGY

Fig. 18. Anterior vertebrae and neural arches oi Kneria wittei, t 79-01-P-516 (SL = 54.3 mm) showing the
elaborate epipleural ribs. Anterior to right.

in other gonorynchiform taxa (i.e., Chanos and
Gonorynchus) showed that fishes smaller than 25
mm were also devoid of scales, the frontals were
separated, and the cranium poorly ossified. Han-
ken (1984) demonstrated the same cranial devel-
opmental pattern as that exhibited in Cromeria
and Grasseichthys (e.g., a reduction in cranial os-
sification, loss of many dermal bones, a separation
of the frontal bones) in the paedomorphic pleth-
odontid salamander Thorius (adult SL about 14
mm). He hypothesized that the limiting factor to
cranial miniaturization is directly correlated to the
minimum size at which the nervous and sensory
structures can function. In essence, the skull shrinks
around the now predominant brain and sense or-
gans (Hanken, 1983). All extraneous bones are
lost. It seems clear that the paedomorphic events
that occur in Thorius are independent from those
that occur in Grasseichthys and Cromeria, and yet
the same pattern of cranial development results in
all. It therefore seems that the similarities existing
among those paedomorphic taxa are the result of
independent paedomorphic events not reflective
of a shared evolutionary history. If we assume that
the characters uniting Cromeria and Grasseichthys
are the result of paedomorphosis, these reductive
characters could be combined as a single character
(i.e., all the result of a single phenomenon— pae-
domorphosis). Then the choice becomes one be-
tween a group containing Cromeria + Grasseich-
thys (supported by the shared phenomenon of
paedomorphosis) versus a group containing
Cromeria + Kneria + Parakneria (supported by

the ventral inclination of the vomer). The value
of reductive characters or losses in phylogenetic
analysis has been demonstrated by Begle (1991).
Those characters, however, must be unambiguous
and shown to be derived reductions and losses by
means of character congruence (Begle, 1 99 1). That
is clearly not the case here. The characters uniting
Grasseichthys and Cromeria seem to be the result
of two independent paedomorphic events, as in-
dicated by the fact that Cromeria shares a unique
nonreductive character with Parakneria and Kne-
ria. Paedomorphosis is therefore obscuring the true
phylogenetic relationships within this family of
gonorynchiform fishes. To unambiguously solve
this dilemma, additional nonreductive character
information is necessary. Characters obtained from
mithochondrial DNA (Grande, in prep.) and the
addition of nonosteological characters to the da-
tabase should help to resolve the phylogenetic re-
lationships of Cromeria within the family Kneri-
idae.

Acknowledgments

Many thanks to Dr. Lance Grande (Field Mu-
seum of Natural History) for reading and com-
menting on various drafts of this manuscript. My
thanks to Dr. Warren Jones (Loyola University)
for helping in the translation of several key sci-
entific papers, Mr. Joseph Schluep (Loyola Uni-
versity) for his photographic expertise, and Ms.

GRANDE: PHYLOGENY AND PAEDOMORPHOSIS IN KNERIIDAE

19

Elaine Zeiger for her clerical expertise. Special
thanks to the Lester Armour Foundation for fund-
ing part of my research and to the University of
Illinois at Chicago for its support for my doctoral
studies in the Department of Biological Sciences.

Literature Cited

Begle, D. 1991. Relationships of the osmeroid fishes
and the use of reductive characters in phylogenetic
analysis. Systematic Biology, 40(1): 33-53.

BouLENGER, G. A. 1901. Diagnoses of new fishes dis-
covered by Mr. W. L. S. Loat in the Nile. Annual
Magazine of Natural History, series 7, 8(47): 444-446.

BucKUP, P. 1991. Computer Program to Generate Lists
of Characters by Hennig 86, D3, Version 2.

DiNGERKUS, G., AND L. D.Uhler. 1977. Enzyme clear-
ing of alcian blue stained whole vertebrates for dem-
onstration of cartilage. Journal of Stain Technology,
52(4): 229-232.

Fink, S. V., and W. L. Fink. 1981. Interrelationships
of ostariophysan fishes (Teleostei). Zoological Journal
of the Linnean Society of London, 72(4): 297-353.

Gayet, M. 1986. Ramallichthys Gayet du Cenoma-
nien inferieur marin de Ramallah (monts de Judee).
Une introduction aux relations phylogenetiques des
Ostariophysi. Memoires du Museum National d'His-
toire Naturelle, Paris, series C, 51: 1-81.

Gery, J. 1964. Une nouvelle famille de poissons dul-
caquicoles africains; les Grasseichthyidae. Compte
Rendu de I'Academie des Sciences, Paris, 259(245):
4805-4807.

GosLiNE, W. A. 1960. Contributions towards a clas-
sification of modem isospondylous fishes. Bulletin of
the British Museum (Natural History), Zoology, 6(6):
336-352.

Grande, T. 1992. Higher interrelationships of Recent
and fossil gonorynchiform fishes. Ph.D. diss.. Uni-
versity of Illinois at Chicago.

. 1993. The interrelationships of Fossil and Re-
cent Gonorynchid fishes and the inclusion of two Cre-
taceous taxa from Israel. Symposium of the Interna-
tional Congress of Mesozoic Fishes, Germany.

Greenwood, P. H., D. E. Rosen, S. H. Weitzman, and
G. S. Myers. 1966. Phyletic studies of teleostean
fishes, with provisional classification of living forms.
Bulletin of the American Museum of Natural History,
131: 339-455.

Hanken, J. 1983. Miniaturization and its effects on
cranial morphology, genus Thorius (Amphibia, Pleth-
odontidae): II. The fate of brain and sense organs and
their role in skull morphogenesis and evolution. Jour-
nal of Morphology, 177: 255-268.

. 1984. Miniaturization and its effects on cranial

morphology in plethodontid salamanders genus Tho-
rius (Amphibia: Plethodontidae). I. Osteological vari-
ation. Biological Journal of the Linnean Society, 23:
55-75.

Howes, G.J. 1985. Cranial muscles of gonorynchiform
fishes, with comments on generic relationships. Bul-
letin of the British Museum (Natural History), Zool-
ogy, 49(2): 273-303.

HuBBS, C. L, AND K. F. Lagler. 1949. Fishes of the
Great Lakes Region. Cranbrook Press, Bloomfield Hills,
Michigan.

JuBB, R. A., AND G. Bell-Cross. 1974. A new species
of Parakneria Poll 1965 (Pisces: Kneriidae) from Mo-
zambique. Amoldia (Rhodesia), 6(29): 1^.

Lenglet, G. 1 974. Contribution a I'etude osteologique
des Kneriidae. Annales de la Societe Royal Zoologique
de Belgique, 22: 52-103.

Myers, G. S. 1 938. Fresh-water fishes and west Indian
zoogeography. Annual Report, Smithsonian Institu-
tion, 1937: 339-364.

Nelson, G. 1973. Relationships of the clupeomorphs
with remarks on the lower jaw in fishes, pp. 333-349.
In Greenwood, P. H., R. S. Miles, and C. Patterson,
eds.. Interrelationships of Fishes. Academic Press,
London.

Nelson G., and N. Platnick. 1981. Systematics and

Biogeography, Cladistics and Vicariance. Columbia

University Press, New York, 567 pp.
Pellegrin, J. 1 905. Poisson nouveau de Mozambique.

Bulletin du Museum National d'Histoire Naturelle,

Paris, 11: 145-146.

Penrtth, M. J. 1973. A new species of Parakneria
from Angola (Pisces: Kneriidae). Cimbebasia, 2: 131-
135.

Poll, M. 1933. Contribution a la faune ichthyologique
du Katanga. Annals de Musee de 1' Belgium Congo,
Tervuren Zoologia, series 1, 3(3): 101-152.

. 1965. Contribution a I'etude des Kneriidae et

description d'un nouveau genre, le genre Parakneria
(Pisces, Kneriidae). Memoires, Academic Royale de
Belgique, series 8, 36(4): 1-28.

Regan, C. T. 1929. Fishes. Encyclopaedia Britannica,
9(14): 305-328.

Roberts, T. 1972. Ecology of fishes in the Amazon
and Congo basins. Bulletin, Museum of Comparative
Zoology, 143: 117-147.

. 1973. Interrelationships of ostariophysans, pp.

397-513. In Greenwood, P. H., R. S. Miles, and C.
Patterson, eds.. Interrelationships of Fishes. Academic
Press, London.

Rosen, D. E., and P. H. Greenwood. 1970. Origin of
the Weberian apparatus and the relationships of the
ostariophysan and gonorynchiform fishes. American
Museum Novitates, 2428: 1-25.

SwoFFORD, D. L. 1 990. PAUP: Phylogenetic analysis
using parsimony, version 3.0. Computer program dis-
tributed by the Natural History Survey, Champaign,
Illinois.

Thys van den Audenaerde, D. F. E. 1961. L'anato-
mie de Phractolaemus ansorgei Boulenger et la posi-
tion systematique des Phractolaemidae. Annales de
Musee Royal de I'Afrique Central, series 8, 103: 99-
167.

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