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FHE NAUTILUS

Volume 104
1990

AUTHOR INDEX

Annis. C G , Jr.
Belancer, T. V.

Bcx;an, a. E

Cairns. J , Jr., . . .

Cherrv, D. S

Coney. C. C

doherty, f. g.
Emberton. K. C.
Emerson. V\'. K
P'airbanks. H. L

CilLMER, R \\

Harasewych. M. G.
houbrick, r. s.

Hl'NTER. R D. ...

. 4 Lodge. DM

4 Marshall, B ,\

29 McLean, J. li

10 Neck, R. W

10 Petuch, E. J 5'

130 Pierce, H. G

10 Richardson, L

■W Robertson, R

108 Rosenberg, G,

71 Sage, W E. Ill 1,

1 1 1 Spamer, E. E

120 Stahl, T

3.5 Toll, R B

87 VanEpps, D. D

10,3

I i

, 96
53
33

145
29

108
29
92
26

. 4

NEW TAXA proposed IN VOLUME 104 (1990)

MONOPLACOPHORA

Micropilina tangaroa Marsli.ill, new .species 107

GASTROPODA

Cvathermiidae McLean, new family (Archeogastropoda) 78

Stjmmetrophalus McLean, new genus ((\!yallierniiidae) 79

Symmctrophalus regitlaris McLean, new Species (Cyathermiidae) 79

Turritella tiiarianopsis Petuch, new species (Turitellidae) 59

Cypraea (Macrocypraea) spengleri Petuch, new Species (Cypraeidae) 97

Cypraea (Pseiidozonaria) porteUi Petuch, new species (Cypraeidae) 97

Chicoreus hilli Petuch. new species (Muricidae) 59

Dermomurex (TrialatcUa) cuna Petuch, new species (Muricidae) 60

Murt'X ruhitlus fxinuniicits Petuch, new species (Muricidae) 62

Mtirexiella eduardpauli Petuch, new species (Muricidae) 62

Miccosukea Petuch. new subgenus (Melongenidae) 99

Melongena (Miccosukea) cynthiac Petuch. new species (Melongenidae) 99

Melongena (Miccosukea) holeylandica Petuch, new species (Melongenidae) 100

Latirus cuna Petuch, new species (Fasciolariidae) 62

Latirus deynzcrorum Emerson and Sage, new species (Fasciolariidae) 1

Milra (Sehularia) leonardi Petuch. new species (Mitridae) 63

Ohta (Strepliona) reticularis erncsti Petuch. new species (Oiividae) 63

Prunum leonardhilli Petuch. new species (Margineiiidae) 63

Falsilyria ernensti Petuch. new species (V'oi\itidae) 64

Sraphella seminolc Petuch. new species (Volutidae) 100

Voluta lacertina Petuch. new species (Volutidae) 64

Conux brunneufilaris Petuch, new species (Conidae) 66

Conus capeletii Petuch, new species (Conidae) 100

Conus ernesli Petuch, new species (Conidae) 67

Conus granarius panamicus Petuch, new species (Conidae) 67

Conus griffini Petuch, new species (Conidae) 103

Conus hilli Petuch, new species (Conidae) 67

Conus lemoni Petuch, new species (Conidae) 103

Conm roscmarijae Petuch. new species (C^onidae) 68

Fusiturrictda sunderlandi Petuch, new species (Turridae) 69

Knejastia hilli Pclucli tii\.. species (Turridae) 70

Procijmhulia phillporum Gilmer, new species (Peraclididae) 112

BIVALVIA

Bellascinlillii Coney ii'"' <p.'cies (Galeommatidae) 137

Bellascintilln parmaUr,. n f miey. new species (Galeommatidae) 138

THE NAUTILUS

Volume 104, Number 1
June 25, 1990
ISSN 0028-1344

A quarterly devoted
to malacology.

iAdU^^i Biological Laboralcr^
LIBRARY

JUL 9 1990

j Woods Hole, Mass.

EDITOR-IN-CHIEF
Dr. M G. Harasewych
Division of Mollusks
National Museum of
Natural History
Smithsonian Institution
Washington, DC 20560

ASSOCIATE EDITOR
Dr. R. Tucker Abbott
American Malacologists, Inc.
P.O. Box 2255
Melbourne, FL 32902

CONSULTING EDITORS
Dr. Riidiger Bieler
Department of Malacology
Delaware Museum of
Natural History
P.O. Box 3937
Wilmington, DE 19807

Dr. Robert T. Dillon, Jr.
Department of Biology
College of Charleston
Charleston, SC 29424

Dr. William K. Emerson

Department of Living Invertebrates

The American Museum of Natural

History

New York, NY 10024

Mr. Samuel L. H. Fuller
1053 Mapleton Avenue
Suffielcl, CT 06078

Dr. Robert Hershler
Division of Mollusks
National Museum of
Natural History
Smithsonian Institution
Washington, DC 20560

Dr Richard S. Houbrick
Division of Mollusks
National Museum of
Natural History
Smithsonian Institution
Washington. DC 20560

Mr. Richard I. Johnson
Department of Mollusks
Museum of Comparative Zoology
Harvard University
Cambridge, MA 02138

Dr. Aurele La Rocque
Department of Geology
The Ohio State University
Columbus, OH 43210

Dr. James H. McLean
Department of Malacology
Los Angeles County Museum of
Natural History
900 Exposition Boulevard
Los Angeles, CA 90007

Dr. Arthur S. Merrill
% Department of Mollusks
Museum of Comparative Zoology
Harvard University
Cambridge, MA 02138

Ms. Paula M. Mikkelsen
Harbor Branch Oceanographic
Institution, Inc.
Ft. Pierce, FL 33450

Dr. Donald R. Moore

Division of Marine Geology

and Geophysics

Rosenstiel School of Marine and

Atmospheric Science

University of Miami

4600 Rickenbacker Causeway

Miami, FL 33149

Mr. Richard E. Petit

P.O. Box 30

North Myrtle Beach, SC 29582

Dr. Edward J. Petuch
Department of Geology
Florida Atlantic University
Boca Raton, FL 33431

Dr. David H. Stansbery
Museum of Zoology
The Ohio State Universit\
Columbus, OH 43210

Dr. Ruth D. Turner
Department of Mollusks
Museum of (Comparative Zoology
Harvard University
Cambridge, MA 02138

Dr. Geerat J. Vermeij
Department of Geology
University of California at Davis
Davis, CA 95616

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TH Ef^NAUTI LUS

CONTENTS

Volume 104, Number 1

June 25. 1990

ISSN 0028-1344

William K. Emerson
Walter E. Sage, III

A new species of Latirua from the Philippine Islands
(Gastropoda: Fasciolariidae)

T^t::

Thomas V. Belanger Growth rates of the Asiatic Clam, Corhicula fluminea, in \

Clifford G. Annis, Jr. the Upper and Middle St. Johns River, Florida J(JL 9 1990 ^

Delmar D. VanEpps 1

' ',

Francis G. Doherty Multiseasonal tissue growth trends in Corhicula fluminea

Donald S. Cherry (Bivalvia: Corbiculidae) from the New River, Virginia 10

John Cairns, Jr.

Raymond W. INeck Geological substrate and human impact as influences on

bivalves of Lake Lewisville, Trinity River, Texas 16

Ronald B. Toll A reaffirmation of the nomenclatural status of Octopus

filosus Howell, 1868, the senior synonym of Octopus
Inimmclincki Adam, 1936 26

Gary Rosenberg Coelatura Conrad, 1853, Caelatura Conrad, 1865 and

Arthur E. Bogan Coelatura Pfeiffer, 1877 (Mollusca): a tale of two

Earle E. Spamer diphthongs 29

Kenneth C. Emberton Eduardus Pilsbry, 1930, a subgenus of Praticolella

Leonard Richardson Martens, 1892 (Gastropoda: Stylommatophora:

Polygyridae) 33

INews and Notices 34

WESTERN SOCIETY OF MALACOLOGISTS

in conjunction with the

SANTA BARBARA SHELL CLUB

is offering a

STUDENT RESEARCH GRANT IN MALACOLOGY

As part of their commitment to the continued study of molkisks, tlie Western Society of Malacologists and the Santa
Barbara Shell (^lub are pleased to announce the availability of grants to support student research in malacolog\ . Funds
are available for actual research costs, including iiut not limited to, field and laboratory equipment, chemicals,
photographic supplies, computer time and supplies, microscope usage fees, and reasonable research travel costs.

ELIGIBILITY

Applicant must be a full time student in a formal graduate or undergraduate degree program.

The thesis, di.ssertation or research project must be focused primarily on the systematics, biology, ecology or
paleontology of marine, terrestrial or freshwater mollusks. Research currently in progress or beginning in the 1990-
91 academic year w ill be considered.

REQUIREMENTS

Five copies of the following ilocuments are required for each application:

1. A completed application form.

2. A proposal, limited to two pages, which discusses the research project and its malacological significance
including details of the work to be aided by this grant.

3. A budget which outlines how the grant funds will be used.

4. A resume or outline of the applicant's academic background.

5. A letter of recommendation from the applicants research advisor.

6. A list of grants and amounts which are currently being received or have been applied for the 1990-
91 academic year.

AWARD

One or more research grants up to $1,500 are available.

APPLICATION DEADLINE

Completed applications musi be received no later than .'J I July 1990. .Awards will be announced
by 15 S(^ptember 1990. Plea.se send applications to:

Malacology Grant

Department of Invertebrate Zoology

Santa Barbara Museum of Natural History

2559 Puesta del Sol Road

Santa Barbara, CA 93105

For further information or applications contact:

Dr. Vida Kenk (408) 924-4894, or Paul Scott (805) 682-4711

THE NAUTILUS 104(l):l-3. 1990

Page 1

A New Species of Latirus from the Philippine
Islands (Gastropoda: Fasciolariidae)

William K. Emerson
Waller E. Sage, III

Department (if Iinertebrates
American Museum of Natural Histors
Ne« York, NY 1002-1, USA

ABSTRACT

Latirus deynzcrorum new species is descril^ed from specimens
obtained in tangle nets set off Bogo, NE Cebu Island, Philippine
Islands and elsew here in the central Philippine Archipelago.

INTRODL'CTION

During the past ten years many new species or otherwise
significant specimens of marine mollusks have Ijeen col-
lected by fishermen from tangle nets set in moderateK'
deep water in the channels off the central Philippine
Islands, mostK in the region of Cebu and Bohol. Speci-
mens of the new species of Latirus described herein were
obtained several years ago from these sources by Major
Al Deynzer of Showcase Shells, Sanibel, Florida, who
recently submitted the specimens for study. We take
pleasure in describing this nev\' ta.xon in honor of Bev
and Al De>nzer, \\ ho, as avid students of mollusks, have
generously shared their discoveries with us and others
through the years.

SYSTEMATIC ACCOUNT

Family Fasciolariidae Gray, 1847
Subfamily Peristerniinae Tryon, 1880
Genus Latirus Montfort, 1810

Type species: by monotypy, Latirus aurantiacus Mont-
fort, 1810 [= L. gihhulus [QmeWn. 1791)], Recent, Indo-
Pacific,

Latirus deijnzerorurn new species

(figures 1-3)

"Latirus sp. Springsteen, 1985:4,

■, fig. 4.

Diagnosis: A mediimi-size latirid, ornamenteil with
prickled varices. Shell somewhat resembles Latirus mac-
ulata (Reeve, 1847; Turbinclla species 70, pi. 13:70a,
70b) from the Indo-Pacific (Springsteen & Leobrera, 1986:
181, pi. 48:22). It differs from Reeves taxon in having a

larger, more angular shell, with a much longer and more
recurved siphonal canal and by distinctive sculptural
characters and color patterns, Peristernia cremnochione
Melvill (1891:397, pi. 2:9), a smaller species attaining 24
mm in length, from Mauritius, more closely resembles
this new taxon in the outline and color pattern of the
shell. Melvill's taxon, however, lacks a siphonal fascicle,
and has a short, straight siphonal canal, characteristic of
Peristernia.

Description: Shell solid, fusiformly elongate, attaining
40-1- iTim in length, whorls angularK rounded, axialh
ribbed and crossed by conspicuous spiral lirae forming
small prickle-like profusions medially on varices, si-
phonal canal narrowly elongated and recurved, outer lip
thin, edge of labrum lirate.

Protoconch glossy, smooth, consisting of 1 Vz embryonic
whorls; postnuclear whorls 6 to 6'/2 in number, with 8 to
9 widely spaced, rounded axial ribs, crossed by about 14
strong spiral cords on the body whorl posterior to the
siphonal canal. Suture partialK obscuretl b\ fluted axial
riblets. Dorsal surface of siphonal canal with 2 prominent
spiral ridges and numerous lesser intervening lirae. Ap-
erture widely ovate, outer lip with weak lirations; col-
umella smooth, with inner margin raised to form a thin
detached edge anteriorly, extending to near the terminal
end of the narrow, recurved siphonal canal; siphonal
fascicle well-formed and strongly corded. For measure-
ments, see table 1. Radula and soft parts not seen.

Color: Protoconch light tan; base color of shell orange
buff, early whorls of spire grayish brown, subsequent
whorls with broken bands of brown forming prominent
blotches (figure 1); some specitnens weakK blotched or
entirely lacking blotches (figures 2, 3); fascicle stained
dark brow n above and w ithin the groove; aperture pink-
ish white.

Type locality: Off Bogo, NE Cebu Island (11°03'N,
124°E), from tangle nets set in moderateK deep water.
May, 1981.

Type depository: Holotype AMNH 232138, 4 paratypes
AMNH 232139; 2 paratypes in the Deynzer collection.

Page 2

THE NAUTILUS, Vol, 104, No. 1

Figures 1-3.

X 1V4.

Type specimens of Latirus deynzerorum new species. 1. Holotype AMNH 232138; 2, 3. Paratypes AMNH 232139;

Range: Known from the type locality in the central
Philippine Islands; also off Panglao Island (9°35'N,
123°48'E), October, 1985, in "deep water," tangle nets,
AMNH 239585 (2 specimens, ex-F. J. Springsteen coll.);
and off Punta Engano, Mactan Island, NE Cebu, in tangle
nets (Springsteen, 1985:4).

Remarks: Our knowledge of the ta.xonomic relation-
ships of the multitude of latirid-like species that are re-
ferable to Peristerniinae genus-group taxa has not pro-
gressed much since the appearance of the early reviews
of Kiener (1840), KiJster and Kobelt (1844-1876), Reeve
(1847), Tryon (1880, 1881), Cossmann (1889) and Melvill
(1891, 1911). At the present time (see Boss, 1982:1016,
1017; Vaught, 1989:50), most of these species are assigned
to either the genus Latirus scnsu tato (with several non-
nominate subgenera), or to the genus Peristernia Mcirch
(1852:99), type species (by subsequent designation: Coss-
mann 1889:166), Turhinella crenulata Reeve (1847, pi.

4, fig. 24). Based on shell characters alone, however,
generic placement of these species is largely arbitrary,
without knowledge of the radular morphology. For ex-
ample, the type of Fu.solatinis Kuroda and Habe (1971:
182), Fusolatirus pilsbryi (Kuroda and Habe, 1971:183,
pi. 50, figs. 1, 2), was described as having '". . . the shell
of Latiriis-form and the radula of Peristernia-{onnu\a.."
Therefore, the precise generic allocation of the new
species described herein must remain provisional until
the nature of the radula is known.

ACKNOWLEDGEMENTS

In addition to Major Deynzer, we thank F. J. Springsteen
for contributing comparative material. We also thank
Andrew S. Modell and Stephanie Crooms of the Amer-
ican Museum of Natural History, respectiveK , for the
photography and word-processing.

Table 1. Latirus deynzerorum new species. Shell measure-
ments of specimens in mm and number of postiiuciear whorls;
widths measured including varices, n = 9. Specimens deposited
in the AMNH collection unless otherwise stated.

No.

Length

Width

whorls

Holotype (figure 1)

39.6

17.3

6'/2

Paratype (figure 2)

39.4

16.4

Paral)pe (figure 3)

33.4

15.3

Paratype (Deynzer

L'Oll.)

34.2

15.7

Paratype (De\nzer

L-Oll.)

33.9

15.0

Paratype

31.0

14.4

Paratype

27.2

12.8

Referred specimens

■>.5..5

16.1

6'/2

(AMNH 2.39.58.51

■■A :}

13.3

LITERATURE CITED

Boss. K. J. 1982. Mollusca. In: Parker, S. P. (ed.). S>nopsis
and classification of living organisms. McGraw-Hill Book
Company, New York, 1:945-1166.

Cossmann, M. 1889. Catalogue illustre des coquilles fossiles
de I Eocene des environs de Paris. .Annales de la Societe
Royale Malacologiqvie de Belgique, Memoires 24(4):3-381.

Gtnelin, J. E. 1791. Caroli a Linne Systema naturae per regna

tria naturae, 13th ed. Leipzig, vol. 1, pt. 6, cl. 6, \'ernies,

p. 3021-3910
Gray, J. E. 1847. .\ list of the genera of Recent Mollusca,

their synonyma and tvpes. Proceedings Zoological Society

of London.'for 1847:129-219.
Kiener, L. C. 1840. Genre Turhinelle, Species general et icon-

ographie des cotjuilles \i\ antes. . . , Paris, 5:1-50. pis. 1-

21.

W. K. Emerson and W. E. Sage, III, 1990

Page 3

Kuroda, T. and T HuIk-. 1971 Iii: kuioda. T., T. llalw and
K. Oyama (eds. ). The sea sliells ot Sagami Bay, collected
by HLs Majest)' The Emperor ol Japan. Marnzen C^o,, To-
kyo, p. i-xix, 1-741. Tokyo, p. \vi + 748 [Japanese text];
121 pis., p. 1-489 [English text], p. 1-51 [index].

Kiister, H C. and \V. Kobelt. 1844-1876. Systematisches Con-
chylien-Cabinet von Martini und Chemnitz, neu heraus-
gegeben Turhinella und Fasciularia. . . . Nuremberg, 3(3a):
1-164.

Melvill, J. C;. 1891. .An historical account of the genus Ldtinis
(Monttort) and its dependencies, with ilescriptions of elev-
en new species, and a catalogue ot Latirus and FeristcnUa.
Memoirs and Proceedings of the Manchester Literary &
Philosophical Societ)', series 4, 4(5):365-411.

Melvill, J. C. 1911. An enumeration of the additions made to
the genus Latirus Montfort, since 1891, with descriptions
of three new species. The Journal of Conchologv 13(6):
164-178.

Moiitlnrt, P. D, dc 1810. t:onch\ liiilogic s\slematique et
classilication methodique des ciHiuilles, . . Paris 2:1-676.

Morch, O. A. L. 1852. C;atalogus conchyliorum quae reliquit
D .Alphonso D'Aguirra et (ladea CJomes de Yoldi. Typis
Ludosici Kleini, Fasciculus Primus, C^openhagen, [Gastro-
poda, etc.], 170 p.

Reeve, L. A. 1847. Conchologia Iconica: illustrations of the
shells of Molluscous animals, vol. 4. Monograph of the
genus Turhinella, text & 13 pis.

Springsteen, V. J. 1985. Some unusual I'hilippine shells, pt.
111. Carfel Philippine Shell News 7(4):3-7.

Springsteen, F. J. and F. M. Leobrera. 1986. Shells of the
Philippines. Carfel .Seashell Museum. Manila, 377 p., illus.

Trvon, G. V\'., Jr. 1880, 1881. Family Fusidae, Manual of
Conchology, series 1, 3(9):46-64, [issued, Jan. 2, 1880];
3(10):65-97 [issued. Mar. 28, 1881].

Naught, K. C. 1989. A classification of the living Mollusca.
American Malacologists, Melbourne. FL. \ii + 195 pp.

THF NAUTILUS 104(l):4-9, 1990

Page 4

Growth Rates of the Asiatic Clam, Corhicula fluminea, in the
Upper and Middle St. Johns River, Florida

Thomas V. Bclanger
Clifford G. Aniiis, Jr.
Delmar D. VanEpps

Departnieiit of (^licinical and
Em iroiiinental Knginecriiig
Florida Institute of Tecfinology
Melbourne, FL 32901, USA

ABSTRACT

Growth rates and population densities of Corhicula jiuminca
were studied over a two year period in the Upper and Middle
St. Johns River, Florida Measured grow th rates were compared
with published data from other systems, and factors influencing
growth rates were identified. Growth rates of C. fluminea were
affected by flow rate and sediment type, and ranged between
0.0043 and 0.0437 mm/day in this study. Corlncula were found
to dominate the sandy sediment regions, usually characterized
by higher flow rates, while unionid mussels inhabited the more
flocculent organic sediments present in slower moving water.
Of the 1,6.50 bivalves collected from dredge samples, 79.3%
were C. fluminea and 20.7/'; were unionids. Unionid growth
was adversely affected by the presence of Corlncula. as mussel
growth rates decreased when numbers of C. fluminea in-
creased.

INTRODUCTION

Corhicula fluminea (Miiiler, 1774) has spread rapidly
throughout the United State.s and has become a species
new to many freshwater systems throughout the country
(McMahon, 1982). It appears that the great success of C.
fluminea is primarily due to its lack of predators, resis-
tance to environmental stresses, tolerance of many sub-
strates, high reproductive ability, rapid growth, and abil-
ity to filter large volumes of water (McMahon, 1977;
Mattice, 1979; Graney et al, 1980; Rodgers et ai, 1980;
Gottfried & Osbourne, 1982). Population density and
growth rate data from various aquatic systems have been
well documented (Gardner et ai, 1976; O'Kane, 1976;
Sickel, 1976; Britton et al., 1979; Kng, 1979; Buttner &
Ileidinger, 1980; Scott-Waslik et ai, 1983; Welch & Joy,
19>-;4; Joy, 1985).

Mtfioiigh macroinvertebrate surveys noting the pres-
'•ula fluminea were conducted in the Upper
S! cr by Mascjn and Beianger (1979), Biizzi

(1979) '.ox ai.'.l Moody (1980) and Llibre (1982), little
is known about the population dynamics and growth
rates of the clams in tjiis river system. The purpose of

this research was to determine population densities, dis-
tributions, and growth rates of C. fluminea in the I'pper
and Middle St. Johns River so that comparisons with other
aquatic systems could be made and possible factors in-
fluencing growth rates could be identified. A secondary
purpose was to investigate the effect of C. fluminea on
the growth of indigenous unionid bivalves.

STUDY AREA

The St. Johns River basin encompasses 18,290 sq. km
and is one of the few large rivers in the world that flows
from south to north. The river originates in the dense
marshes of St. Lucie County and flows approximately
300 km north to the Atlantic Ocean, east of Jacksonville,
Florida. The topography of the study region is relatively
flat, resulting in a shallow river-lake system. This study
considered the upper and middle sections, with sampling
sites extending from Zig-Zag Canal, Brevard County, to
Lake Monroe, Seminole County (figure 1).

MATERIALS AND METHODS

Clams were collected at all sites from August 1983 through
May 1984. Caged clams were maintained in the field
during three separate periods, September 1983 to July
1984, August 1984 to February 1985, and February 1985
to July 1985. Each clam was measured to the nearest
0.05 mm for length (greatest anterior-posterior distance),
width (greatest distance through the valves), and height
(gre^itest dorso-ventral distance perpendicular to the the
hinge line), using vernier calipers. Clams were measured
before being placed in the cages and after retrieval.
C^ages were constructed from 19-liter plastic buckets and
approximately 100 holes 1 cm in diameter were drilled
in the sides of each container. The bottom of each cage
was filled with acid-waslied .sand to a depth of 25 cm
and the cage fitted with a locked lid. Ten (first and second
study periods) to 15 clams (third study period) were
placed in each cage. In addition, five cages were placed

T. V. Belanger et ai. 1990

Page 5

R 60
Ver o Beoch

lor Ida
ur npike

Figuro 1. Thf St Johns River hasin with Ideation of sampling
sites. 1 = Zig-Zag Canal*; 2 = Lake Sawgrass Outlet; 3 = Camp
Holly (Route 192)**; -4 = Lake Washington; 5 = Lake Wash-
ington Outlet**; 6 = Lake Poinsett Outlet; 7 = Route 50 Bridge;
8 = Lake Harne> Inlet Bridge; 9 = Lake Harney Outlet; 10
= Lake Jessup Outlet, 11 = Lake Monroe Inlet*; 12 = Lake
Monroe Outlet*; 13 = Lake Monroe Power Plant Outfall; * =
sampling and cage site; ** = cage site only.

at the Lake Washington site to determine the effect of
Corbicula fluminea populations upon the growth rates
of unionid mussels. In this experiment, ten unionid mus-
sels (Elliptio sp.) were placed in each cage together with
C. fluminea in densities equivalent to 500, 1,000, 2,000
or 3,000 clams/m^. After five months, the unionid mus-
sels were retrieved and measured to determine growth
rates. Water quality parameters (depth, dissolved oxygen
[D.O.], water temperature, flow rate, pH, and percent
sediment volatile solids) were measured routinely (at least
bimonthly) using standard techniques (A. PH. A., 1980).
The mean values for these parameters at the sites are
presented in table 1.

RESULTS AND DISCUSSION

Population Density and Distribution

Population densities of Corbicula fluminea varied widely
along the St. Johns River system. Of the 1 1 sites sampled,
only one site (Site 12) was completely devoid of clams.
With the exception of the Lake Jessup site (Site 10), clams
were found in densities greater than 100/m- at least once

Table 1. Mean plusical and chemical data from routine sam-
pling at selected sites in the Upper and Middle St. Johns River.
Data were collected at least bimonthK from August 1983 through
May 1984.

Sedi-

ment

Flow

vol.

Depth

DO*

Temp*

rate*

solids

Site

(m)

(mg/l)

CC)

(ft/sec)

(%)

2.9

3.0

20.0

0.09

6.69

13.72

2.0

4.7

21 0

0 20

7.19

18.20

:an

-4

1.5

5.6

23.0

001

7.70

3.34

2.5

6.1

22.0

0.30

7.42

2.00

3 4

4.9

22.0

0 19

7.04

4.73

2.6

5.3

20.7

0.47

724

2.13

2.7

8.0

19.5

0.29

7.71

7.35

2.4

8.2

20.4

0.20

8.74

3.70

4.3

5.7

23.2

0 39

7.88

474

5.8

24.3

0.16

8.23

11.42

4(1

5 5

20 9

0.17

8.30

3.14

Measured near sediment-water column interface.

during the nine sampling events. Four sites contained
densities greater than 1,000/m-, with Lake Harney Inlet
(Site 8) exhibiting the maximum density of 2,700 indi-
viduals/m- in November, 1984. Table 2 lists the popu-
lation densities of C. fluminea recorded throughout the
study. Only juveniles were found in Zig-Zag Canal (Site
1), where they did not become established.

When only adult populations are considered, some
generalities may be draw n from the data. Corbicula flu-
minea were most abundant in sandy sediment with low
organic content, such as the Lake Harney Inlet site (Site
8), where the highest mean monthly density of 839 clams/
m- was recorded. Sandy substrates were favorable for C.
fluminea growth from Lake Washington (Site 4) down-
stream to the Lake Harney Inlet (Site 8), and clams from

100

80--

o 60--

Total: 1,268 clams

1 2 4 6 7 8 9 10 11 12 13

Figure 2. Corhiciila fluminea population distributions, at the
Upper and Middle St. Johns River sampling sites, 1983-84. (%
frequencN = Corbicula percentage of total collected inverte-
brates at each site; dotted line = only juvenile clams)

Page 6

THE NAUTILUS, Vol. 104. No. 1

Table 2. Carbicula fluminca population densities (no 'm^'), from sanipliriK .sites in tlie Upper and Middle St Johns Hi\er (.August
1983-Mav 1984)

198:5

1984

Site

Aug

Sep

Oct

Nov

Jan

Feb

Mar

.Apr

May

Mean

*1.417

*233

*250

—

*211

464

—

150

—

600

567

217

117

217

433

250

229

183

117

700

383

583

—

230

263

200

283

117

433

517

1,033

183

217

344

292

—

2,217

2,700

233

2,217

167

—

839

1,166

—

100

—

117

367

267

—

188

162

—

783

1,083

1,217

627

572

* — Ju\cni

le elanis

onl\.

NS — Not sampled.

these sites represented 68% of the total clams collected.
Helanger et al. (1985) reported similar results and sug-
gested that rivers with fine, well-oxygenated sand sub-
strates would be optimal for the establishment of C.
fluminca populations in newly colonized sites.

The distribution ol C. fluniinea in the Llpper and
Middle St. Johns River (figure 2) is primarily related to
sedinu'iit t\ pe and flow rate. The distribution of C. flii-
minea varied from 34.2% of the total fauna at the Lake
Harney Inlet site (Site 8) toO% at the Lake Monroe Outlet
site (Site 12), where deep deposits of organic sediment
occurred. Also, few clams were observed in the upper
reaches of the study area (Sites I and 2), as peat sedi-
ments, low flow rates and low dissolved o.xygen conditions
predominated.

.\lthough it was found that both sediment type and
Dow rate affected the density of C. fluminea populations,
results from this study indicated sediment type was the
most important limiting factor, as high flow can be in-
effective if the sediment type is imsuitable. For example,
samples taken from organic muck and peat .sediments

revealed only small numbers of C. fluminea. even though
flow rate was often suitable. The reverse situation, sandy
sediment and no flow, was encountered at the Lake
Washington site (Site 4) where an average clam density
of 250/m- was found. Flow rate is an important factor
because it is responsible, in part, for the transport of
essential materials to the clams, such as food and oxygen.
It is also important for the dispersal of waste products
and clam larvae. However, it appears that a very high
flow rate can limit C. fluminca. At Camp Holly, ap-
proximately 1 km upstream of the Lake Washington site,
the flow rate averaged 1.0 ft/sec over sandy substrate
during sampling trips but no clams were found. Obser-
vations using SCL'BA revealed that the high current had
.scoured the sediment surface, exposing hard-packed sand.
Under these sediment and flow conditions it is very dif-
ficult for clam larvae to become established in the river-
bed. Instead, they are generally swept downstream to
sites where the current velocity has decreased, enabling
them to settle out. The natural spread of C. fluminea is
limited bv the nonswimming larval stage, thus river cur-

Table 3.

Elliptio sp. population density (no. nr) at tlie sanipl

ling sites, 1983-84.

1 ^)8.>

1984

Mean

Site

Aug Sep Oct Nov Jan

Feb Mar

Apr

May

2
4
6

•I

1 1

100

*4,866

* — Juvenile cLiiiit- ur.l\
NS— Not sampled

133

—

17 50

NS NS NS

\541

1,622

T. V. Belanger et at., 1990

Page 7

rent can be an important dispersal mechanism leading
to rapid down-river range expansion (McMahon, 1982).
Corbictila fltiminea population densities in the St. Johns
River are intermediate to the ranges reported in other
areas of the United States. Hall (19(S4) reported densities
as high as 6,663 clams/m- in the littoral zone of Lake
Norman, North Carolina. Eng (1979) found C. fluminea
population densities in sand bars in the concrete lined
Delta-Mendota Canal in California to be between 10,000-
20,000 clams/m-. Population densities of C. fluminea
were noted to be greatest in fine sand (452 clams/m-),
followed by sand/gravel substrata (177 clams/m-) in the
New River, Virginia (Belanger et ai, 1985). In a study
on the Wekiva River, F"lorida, Gottfried and Osbourne
(1982) reported population densities of 1,210 clams/m".
Gardner et al. (1976) reported the C. fluminea popu-
lation density increased from 0 to 10,000 clams/m- from
1971 to 1974 in the Altamaha River, Georgia.

Effects of Cohbicvl.x Den.sities on Unionids

I'nionid mussels (Elliptio sp.) were observed in much
lower population densities than Corbicula fluminea. Al-
though mussels occurred in high density (4,866 clams/
m-) at the Zig-Zag site, this number represented only
larval mussels and neither C. fluminea nor Elliptio sp.
became established at this site during the study. The
largest adult population of unionids was found at the
Lake Sawgrass site (Site 2) in November, when 133
unionids/m- were collected. All other sites contained
densities of 50 unionids/m- or less, and adult populations
were found at only six of the eleven sites. Table 3 shows
the mean population densities of unionids at the sampling
sites and indicates that density decreases downstream,
with few mussels occurring downstream of the Lake
Poinsett site (Site 6).

Elliptio sp. population densities were inversely cor-
related to those of Corbicula fluminea (F test; p < 0.05).
As the mean C. fluminea population density increased
in a downstream direction through the first six sites, £/-
liptio sp. mean population densities decreased to zero.
Of 1,600 bivalves collected from dredge samples, 79.3%
were C. fluminea and 20.7% were of the family Union-
idae (Elliptio sp. ). Only in the upper reaches of the river,
where peat sediments dominated, were Elliptio sp. pop-
ulation densities greater than those of the Asiatic clam.
In sandy regions where both bivalves occurred, C. flu-
minea predominated. Thus, Elliptio sp. predominated
only where the sediment type was limiting to C. flu-
minea.

SCUBA diving observations at Lake Harney Inlet (Site
8) showed that unionids do exist at the site, even though
no individuals were captured in the dredge samples, and
revealed the distributional relationships of the two bi-
valves under natural conditions. In general, Corbicula
fluminea outnumbered Elliptio sp. in the central region
of the channel where sandy sediments and measurable
flow existed. Toward shore, the sediments changed from
sand to silt-covered sand, and then to sand covered with

2.00

.50

1/1 1.00

■» 0.50

I July 12 - Oct. 28, 1984 )

0 500 1000 3000

CORBICULA DENSITY (#/m2)

Figure 3. Cage experiments data .showing the effect of Cor-
hicula fluminea densities on grovvtli of Elliptio sp.

heavy accumulations of silt and detritus. Increasing or-
ganic silt accumulations near the river banks were ac-
companied by increasing numbers of unionids. In con-
trast, the number of C. fluminea decreased as silt
accumulation increased. It appeared that C. fluminea
could not tolerate silt accumulations deeper than 0.5 to
1.0 cm. As the silt depth increased beyond 1 cm, only
unionid mussels were observed. The size and shape of
the shell of Corbicula fluminea may contribute to its
preference for sandy substrates. Corbicula fluminea shells
are more circular in comparison to the elliptical shape
of the Elliptio sp. Unionid bivalves, being elliptical and
usually larger, may extend their shells and siphons be-
yond the silt while still remaining within the firm sandy
substrate below. In the case of C. fluminea. only large
specimens would be able to accomplish this. Smaller C.
fluminea. such as those found at Site 8 (20-25 mm size
class), would not be able to extend their siphons beyond
the silt or muck layer to the more oxygenated flowing
river water. The 20-25 mm and 15-20 mm shell-length
size classes were the dominant groups collected in the
St. Johns River, comprising 46%- and 23% of the C flu-
minea found, respectively.

Several investigators have reported that Corbicula flu-
minea can outcompete native unionid and sphaeriid bi-
valves (Boozer & Mirkes, 1979; Cooper & Johnson, 1980;
Taylor & Hughart, 1981). In thisstud\ , growth of Elliptio
sp. and C. fluminea were observed together to confirm
previous observations that unionid population densities
are inversely correlated with C. fluminea population
densities. Elliptio sp. mussels, placed in control cages,
increased their shell length by an average of 1.76 mm
during the period between July 12 and October 28, 1984.
Elliptio sp. growth rates in cages that contained various
densities of C. fluminea were reduced and the reductions
in growth were related to the po[)ulation density of the
Asiatic clams in each particular cage. Figure 3 shows the

Page 8

THE NAUTILUS, Vol. 104, No. 1

Table 4. Curbicula growth rales from representative areas of the I nited States

Growth rale

Site

Measurement period

(mm/day)

Reference

St. Johns River, FL

Lake Washington

10/28/84-2/22/85

0.03

This Study'

Lake Monroe Inlet

8/15/84-2/23/85

0.0197

Lake Monroe Outlet

8/13 S-)-2 23/85

0.0296

Lake Washington

2/23 85-7 22/85

0.0112

Lake Harnev Inlet

2/23/85-6/30/95

0.0437

St. Johns River. FL

Zig-Zag Canal

1/8/84-7/2/84

0.0063

Camp Holly

9/15/83-7/2/84

0,0273

Lake Washington

1/8/84-7/2/84

0.0060

Lake Monroe Outlet

11/13/83-7/2/84

0.0043

Southern Illinois Fish Poiul

Summer

7/20/79-9/22/79

0.012

Buttner and Heidinger (1980)-

Winter

12/6/79-1/16/80

0.003

Selected Texas Reservoirs

1975

0.044

O'Kane (1976)

.Altamaha River. C,.\

1975

0.072

Sickel (1976)

Oelta-Mendota Canal, C\

2/20/73-6/25/73

0.0516

Eng (1979)

Lake Renbrook, TX

Sandbar Specimens

6/7/75-9/9/77

0.056

Britton et al. (1979)'

Container Specimens

6/14/77-9/30/77

0.054

Kanawha River, WV

Container Specimens

3/12/83-12/16/83

0.094

Jov (1985)^

Lake Frie, OH

6/82-9/82

0,114

Scott-Wasilk ('/ al. (1983)

Kanawha River, WV

Container Specimens

Summer, 1983

0.136

Welch and Jo\ (1984)^

1 = 19 liter containers (cages) — with covers, placed on the bottom

2 = Open top cages, 0 3 m- and 9 cm deep, placed on the bottom.

3 = Floating units (each unit consisted of .5 cages).

effect of C. fluminea population den.sities on the growth
rates of Elliptio sp. The reductions in growth rates were:
19.3% when the C. fluminea population density was 500
clams/m-; 40.9% for a density of 1,000 clams/m- and
37.5% at a density of 3,000 ciams/m-. The steady de-
crease in FJliptio sp. growth is evident at C. fluminea
population densities up to 1,000 clams/m-. Beyond this
point, for reasons unknown, growth rate reduction seemed
to level off. The decreases in growth rate of the Unionidae
may have been due to increased competition for essential
requirements such as food or oxygen.

In summary, the growth and distribution of Corbicula
fluminea in the St. Johns River .seems to be related to
substratum and Dow rate. Elliptio sp. growth was ad-
versely affected by the presence of C. fluminea. How-
ever, the adaptability of this unioiiid mu.ssel to organic
sediment types which are generally uninhabitable by C.
fluminea may serve to protect it from the dangers of
overcrowding or the possibility of becoming replaced
altogether by populations of the Asiatic clam.

Growth Raiks

A summary of Corhicula fluminea growth rates at the
cage sites, and ;i comparison with growth rates reported

from other areas of the United States, are presented in
table 4. Fastest growth was seen at Lake Harney Inlet
(Site 8) during the third sampling period (0.0437 mm/
day), as all conditions for growth were favorable at this
site (high flow, high D.O., sandy sediment). In general,
growth rates in this study were intermediate in com-
parison to rates reported in other areas of the United
States (table 4), although very low rates were measured
at the Zig-Zag (Site 1), Lake Washington (Site 4) and
Lake Monroe Outlet (Site 10) sites. The average growth
rates reported by Eng (1979) from concrete lined canals
in (California, were 0.45 and 0.70 mm for the months of
March-May in 1974 and 1976, respectively. By com-
parison, the St. Johns River C. fluminea grew an average
of 0.70 mm and 1.00 mm during the same months in
1984 and 1985. The data in table 4 were collected from
many different aquatic systems with site specific varia-
tions in habitat conditions which undoubtedly affect
growth rates. Britton et al. (1979) reported on clams
grown in lake environments in northern Texas, while the
St Johns Ri\ er clams inhabit hiimic-colored waters under
both lake and river conditions. The most important fac-
tors leading to slower C. fluminea growth in the St. Johns
River than in many other areas were probably the lack
of food due to low flow rates, periodic low oxygen levels

T. V. Bellinger et al.. 199U

Page 9

in the water column and the predominance of organic
sediment in the river.

ACKNOWLEDGEMENTS

The authors with to thank John Platko and Jim Yount
for their valuable assistance throughout the course of this
research.

LITERATURE CITED

.American Public Healtli .Association 1980 Standard methods
for the examination of water and wastewater, 15tli etl
.\ P H A , Inc , NY

Belanger, S. E.. J. L. Farris, D. S. Cherry, and J. Cairns, Jr.
1985. Sediment preference of the freshwater Asiatic clam,
Corbicula fluminea. The Nautilus 99(2-3):66-73,

Boozer, A. C. and P. E. Mirkes. 1979. Observations on the
Fingernail clam, Museulium partumeium ( Pisidiidae) and
its association with the introduced Asiatic clam, Corbicula
fiuminea. The Nautilus 94(4):1:30-1.'3.5.

Britton, J. C, D. R Coldiron, L, P Evans, C Golightly, K D
O'Kane, and J. R TenEyck. 1979. Reevaluation of the
growth pattern in Corbicula fluminca (Miiller) /)!; Brit-
ton, J. C. (ed.). Proceedings ot the First International Cor-
bicula Symposium, Texas Christian University Research
Foundation, Fort Worth, Texas, p. 177-192.

BuUner, J K and R. C Heidinger. 1980 Seasonal \ariations
in growth of the Asiatic clam, Corbicula fluniinea (Bi-
valvia: C^orbiculidae) in a Southern Illinois fish pond The
Nautilus 94(1):8-10,

Buzzi, R. A- 1979. Macroinvertebrates of Lake Washington.
M.S. Thesis, Floriila Institute of Technolog\ , Melbourne,
Florida, 62 p.

Cooper, C. M. and \' W Johnson 1980 Bivalve Mollusca of
the Yalobusha River, Mississippi, Tlie Nautilus 94:22-24.

Cox, D T. and D L. Moody. 1980 .\nnual progress report
for research project F-.'33-4. Florida Game and Fresh Water
Fish C^immission, Tallahassee, Pdorida, 218 p,

Eng, L, L. 1979, Population dynamics of the .Asiatic clam,
Corbicula fluminca (Miiller), in the concrete-lined Delta
Mendota Canal of Central California. In: Britton, J C.
(ed.). Proceedings of the First International Corbicula
Symposium, Texas Christian University Research Foun-
dation, Fort Worth, Texas, p. 39-68,

Gardner, J .A,. W, R, Woodall, A, A, Staats, and J F Napoli
1976 The invasion of the .Asiatic clam (Corbicula rnan-
ilcnsis Philippi) in the .Altamaha River, Georgia The Nau-
tilus 90(3):1 17-125,

Gottfried, P K and J, .A Osbourne 1982 Distribution, abun-
dance and size of Corbicula rnanilensis (Philippi) in a
spring-fed Central F'lorida stream. Florida Scientist 45(3);
178-188.

Cirane), H L, D S Cherr\, J H Rodgers, and J Cairns, Jr
1980, The influence of thermal discharges and substrate
composition on the population structure and distribution
of the Asiatic clam, Corlricula fluniinea. in the New River,
Virginia, The Nautilus 94(4): 130-135,

Hall, J, J, 1984, Production of immaiuTe C'orbicula fluntinca
(Bi\alvia: C-orbiculidae) in Lake Norman, North CJarolina,
The Nautilus 98(4):153-1.59,

Jov, J, E. 1985, A 40-week study on growth of the .Asian clam,
Corbicula flumenea (Muller), in the Kanawha River, West
Virginia, The Nautilus 99(4):1 10-1 16,

Llibre, J H 1982 Benthic macroinvertebrates, biological
indicators, and diversity indices ot the I'pper St. Johns
River, Florida MS Thesis, Florida Institute of Technol-
ogy, Melbourne, Florida

Mason, D, R, and T \', Belanger, 1978, Lake Washington:
final report Dei)artment of Environmental Science and
Engineering, Florida Institute of Technolog), .Melbourne,
Florida,

Mattice, J, S 1979 Interactions of Corbicula sp with power
plants. In: Britton, J. C. (ed.). Proceedings of the First
International Corbicula Symposium, Texas Christian L'ni-
versitv Research Foundation, Fort Worth, Texas, p, 119-
1.38,

McMahon, R, F 1977, Shell size-frequenc\ distrilnitions of
Corbicula rnanilcnsi.s Philippi from a clam fouled stream
condenser. The Nautilus 91(2):54-59.

McMahon, R F 1982, The occurrence and spread of the
introduced Asiatic freshwater clam, Corbicula fluniinea
(Miiller), in North America: 1924-1982, The Nautilus 96(4):
134-141,

O Kane, K, D, 1976, .A po])ulation studs of the exotic bixaUe
Corbicula rnanilensis (Philippi, 1841) in selected Texas
Resersoirs, MS, Thesis, Texas Christian Universit\, P'ort
Worth. Texas.

Rodgers, J. H., D. S. Cherr\ , R. L Grane\, K L Dickson, and
J. Cairns, Jr. 1980. Comparison of heavy metal inter-
actions in acute and artificial stream bioassay techniques
for the Asiatic clam (Corbicula fluminea). In: J. G Eaton.
P. R. Parrish and A. C. Hendricks (eds ). .Aquatic Toxi-
cology. .Am, Soc, Test, Mater, Philadelphia, Pa,: 266-280

Scott-Wasilk. J , J S Lietzow, G, G Downing, and K, L Clay-
ton, 1983, Growth of Corbicula fluminea in Lake Erie,
North American Benthological Society 31st .Annual Meet-
ing, La Crosse, Wise, 27-29 April,

Sickel, J, B, 1976 Population growth and productivity of
Corbicula rnanilensis (Philippi) in the .Altamaha River,
Georgia, ASB Bulletin 23(2):96,

Taylor, R, W, and R, C, Hughart, 1981, The freshwater naiads
of Elk River, West \'irginia with a comparison of earlier
collections. The Nautilus 95:21-25,

Welch, K J and J E, Joy 1984 Growth rates of the Asiatic
clam, Corbicula fluminea (Miiller), in the Kanawha River,
West Virginia, Freshwater Invertebrate Biology 3:139-
142.

THE NAUTILUS 104(1):10-15, 1990

Page 10

Multiseasonal Tissue Growth Trends in Corbiciila fliiminea
(Bivalvia: Corbiculidae) from the New River, Virginia

Francis G. Dohcrty'
Donald S. Cherry
John Cairns, Jr.

Dt-parliiifiit of Biology and

I'niversity Center for

Environmental and Hazardous

Materials Studies
\ irginia Foiytechnic Institute and

State University
Biacksburg, VA 24061, USA

ABSTRACT

Juvenile and adult Corhirula fluminea were collected monthly
in 1985 from the New Biver in Narrows, Virginia. Shell length,
shell height, shell inflation, and soft tissue dry weight were
recorded for each individual Regression analyses among all
pairs of data sets were calculated monthly All comparisons
among shell dimensions and between shell dimensions and dry
tissue weight generated coefficients of determination (B-)
>0.801. In all instances, comparisons between shell dimensions
and the cube root of dry tissue weight generated higher R-
values than comparisons between shell dimensions and dry
weight. A comparison of monthly regression lines generated
between shell secretion and the cube root of dry weight suggests
that shell accretion and ti.ssue grow th are not equivalent for all
individuals in a population and are dependent on initial size
of an individual and on season.

Key words: Corlncula fluminea: Asiatic clam; shell dimen-
sions; tissue weight; regression analvsis.

INTRODUCTION

Studies assessing the growth of Corbicula fluminea (Miil-
ier, 1774) have been conducted previously to establish
energy budgets for juveniles (Foe & Knight, 1986a), de-
termine the effect of various artificial and algal diets and
suspended sediment on growth (Dauble et al., 198,5; Foe
6i Knight, 1985), or monitor growth rates of clams under
natural conditions (Welch & Joy, 1984; Joy, 1985). In
general, these studies monitored individually marked
clams or narrow size ranges of clams in the laboratory
for defined durations (usually <30 days) or in the field
for as long as 4 years. Potential applications for data
collected in such studies include use of growth rates as

' Present Address: Syracuse Research Corporation, Merrif
Lane, Syracuse. NY 13210.

a sublethal monitor for exposure of clams to to.xic ef-
fluents and chemicals (Reianger et ai. 1986a, b; Foe &
Knight, 1986b), estimation of soft tissue mass based on
shell size in aquaculture efforts (Joy & McCoy, 1975;
Buttner, 1986), calculation of condition indices to deter-
mine levels of physiological fitness (Joy, 1985), and per-
haps as a means by which decisions may be reached
concerning optimal periods for chemical control efforts
in fouling populations. Few, if any, of these studies ad-
dressed growth of both shell and soft tissue simultaneous-
ly over a continuum of clam sizes in a natural population.
The present study was undertaken to document rela-
tionships in tissue weight and shell size in a natural pop-
ulation of C. fluminea for a minimum of 1 year to de-
termine if the two parameters provided equivalent
conclusions concerning growth in C. fluminea.

MATERIALS AND METHODS

Specimens were collected from the New River at Nar-
rows, Giles County, Virginia, on the last Monday of each
month during 1985. Clams were sampled by means of
a .3-m handled dredging cage (mesh size = 7.0 mm),
permitting collection of individuals as small as 6 mm in
shell length (SL). Clams were returned to the laboratory
within 2 hr of collection for measurement of shell di-
mensions and dry tissue weights (DW) of 100 individuals.
Voucher samples of intact clams have been deposited
with the Department of Malacology at the Academy of
Natural Sciences in Philadelphia (ANSP A12516).

Shell dimensions measured included shell length (SL),
the maximum anteroposterior dimension; shell height
(SH), the distance between dorsal and ventral margins
of the shell measured at the apex of the umbo; and shell
inflation (SI), the lateral thickness of a bivalve (Britton
& Morton, 1982). Shell dimensions were measured with
vernier calipers to the nearest ±0.05 mm on the intact
animal. Prior to shucking the soft tissues from the shell.

F. G. Dohertv cf al., 1990

Page 11

35i

'to

.2 10

Discharge
Temperature

< I I

J F M

J J

Month

1 I

O N D

■30

«^

►-

Figure 1. Mean vveekls water temperature (Narrows) and mean dail\ discharge rate (Radford) for the New River, Virginia, in
1985.

mantle cavity water was drained from the clam by sev-
ering the shell adductor muscles and standing the clam
on the ventral edges of its shell over absorbent paper
toweling. Soft tissues were scraped from the shell, trans-
ferred to preweighed aluminum pans, and dried in a
drying oven at 80 °C for 48 hr. Pans with tissues were
weighed on a Mettler balance to the nearest ±0.5 mg.
Abiotic data available at the time of the study included
New River water temperatures and discharge levels pro-
vided by a local industry and federal agency, respectively
(figure 1).

Least squares regression (LSR) analyses were per-
formed monthly among shell dimensions (SL, SH, SI),
between individual shell dimensions and DW, and be-
tween individual shell dimensions and the cube root of
tissue dry weight (CRDW). Regressions of CRDW against
a shell dimension resulted in a linearization of the allo-
metric relationship between the untransformed variables
(Schmidt-Nielsen, 1984). Generation of LSR analyses was
facilitated by programs (general linear models) of the
Statistical Analysis System (SAS Institute, Inc., 1982).
Coefficients of determination (R-) were generated in con-
jvuiction with the LSR analyses as a feature of the com-
puter programs employed.

RESULTS

All comparisons among shell dimensions and between
shell dimensions and tissue weights generated a R- >
0.801 (table 1). The highest R- values were generated

between SH and SL for shell dimension comparisons and
between SH and CRDW for comparisons between a shell
dimension and dry tissue weight. Values for R' ranged
from 0.988 to 0.996 and 0.895 to 0.970, respectively.
Linear regressions of CRDW against shell dimensions
always generated better lines of best fit than regressions
between untransformed variables.

Intermonthly comparisons of regressions between SH
and CRDW revealed marked seasonal trends in weight
gain and loss relative to a constant shell size (figures 2-
5; table 2). The monthly regression lines are presented

Table 1. Coefficient of determination (R-) ranges for com-
parisons among all potential pairings of shell dimensions and
untransformed as well as transformed dr> tissue weights for all
collections in 1985.

Parameters

compared*

Minimum R-

Ma.vimum R-

SH, SL

0.988

0.996

SL, SI

0.980

0 990

SH, SI

0.922

0.992

SL, DW

0.826

0-953

SL, c;rdw

0.884

0.958

SH, DW

0.832

0.949

SH, CRDW

0.895

0.970

SF, DW

0.801

0.935

SI, CRDW

0.865

0.953

* CRDW = cube root dr\ weight, DW = dry weight, SH
shell height, SI = shell inflation, SL = shell length.

Page 12

THE NAUTILUS, Vol. 104, No. 1

Table 2. Regression parameters and coefficients ol dcternii-
nation (R-) for lines of best fit equations predicting the cube
root of dry weight from shell height for clams collected on a
monthly basis in 1985 from the New River, Virginia, at the
colleclioti temperatures listiil

Collec-

tion

temper-

ature

Month

Slope

Y-Iiitercept

R-

January

0.0185

0.031

0.955

2.0

February

0.0178

0 033

0.914

5.0

March

0 0194

0.037

0.924

7.8

April

0.0195

0.073

0.895

15.0

May

0.0258

-0018

0.970

19.4

June

0.0230

-0.009

0.960

22.5

July

0.0215

0005

0.935

22.0

August

0.0191

0017

0.939

22.0

September

0.0182

0 026

0.956

17.0

October

0.0178

0.028

0.943

16.0

November

0.0188

0 0.33

0.960

December

0 0192

0028

0.960

2.0

in chronological order in figures 2, 3, and 4 to illustrate
the month-to-rnonth progressions. Selected monthly
regression lines are presented in figure 5 to illustrate
comparisons between seasons Although there was a trend
towards declining dry weight in all clams in February
relative to the initial collection in January, CRDW in-
creased among all clams through April (figure 2). This

was demonstrated by progressively higher Y-intercepts,
indicating that increases in tissue mass surpassed in-
creases in SH (table 2). As a point of reference, a 15-mm
(SH) adult possessed 81.5% more tissue (DW) in April
than it did in February. The relationship between CRDW
and SFJ shifted in May from that previousK observed,
as demonstrated by an increase in the slope of the regres-
sion line. Larger individuals (>13 mm SH) possessed
more tissue mass relative to SH than in previous months,
while smaller individuals (<13 mm SH) had less tissue
relative to SH in May than in previous months (figure 2;
table 2). Declining slopes and increasing intercept values
were observed from May through October (figures 3, 4;
table 2) until a distinct increase in CRDW relati\e to SH
was observed in November and December (figures 4, 5).
This shift in the regression lines coincided with major
flooding of the New River in early November (figure 1).
As a point of reference, a 15-mm (SH) adult possessed
22 and 23% more tissue (DW) in November and Decem-
ber, respectively, than it did in October.

DISCUSSION

Regressions among shell dimensions and between shell
dimensions and tissue dry weights generated high R-
values that were comparable to the findings of other
investigators. The approach to analysis of the data gen-
erated in this study differed from that used by others, in
that some investigators failed to transform their data (Joy
& McCoy, 1975; Rodgers et al., 1977) while others uti-
lized a log-log transformation prior to generating lines

06-
04-

^ 0.2

I 06-1

?r> 0.4-

0.0

— r-
8

— r-
4

— I—
12

—I —
16

Shell Height (mm)

Figures 2-5. Ni'.nlhlv lines of best fit for the cube roots of tissue dr\ weiglit regressed against shell height for CorhUula fluniinea
indi\idudK o.Jlf. I. d troni the New River, Virginia, in (2) January, February, March, .Xpril, and May; (3) May. June, and .August;
(4) August SeptcMili r October, and November; and (5) February/October, ,\pri], November, and December, 1985.

F. G. Dohertv ct al., 1990

Page 13

of best fit through regression analysis (Sickel, 1979; Al-
dridge & McMahon, 1978; Kennedy & Heukelem, 1985;
Foe & Knight, 1986a, 1987). Comparisons between a shell
dimension and either viscera wet or dry weight reveal a
curvilinear relationship that is not appropriate!) ana-
lyzed b> linear regressions. While log-log transformations
do provide a linearization of the relationship between
these variables, we believe that use of a cube root trans-
formation may be more biologically appropriate, because
body weight is a function of volume and height is a
measure of a single, linear dimension. Transformation
of weight to its cube root permits a simpler linear regres-
sion comparison between shell dimensions and tissue
weight rather than regressions between log-log trans-
formed variables. Previously, Dauble et al. (1985) uti-
lized a similar approach by regressing the square root of
clam weight against SL. One other factor distinguishing
our study from those previously reported is that all of
the above cited studies used either SL or SI in regressions
against tissue weight. Our data demonstrate a lower de-
gree of variability in measurements of SH and, therefore,
greater precision in the estimation of tissue weights.

Regressions of CRDW against SH (figures 2-5; table
2) demonstrated that no single monthly or quarterly es-
timate of tissue mass based on SH can be extrapolated
to all other periods of the year. Consistent slopes for the
relationships from January through April suggested that
the individuals from all size classes were responding to
environmental variables in a proportionately common
fashion through either the loss (January to February) or
accumulation (February through April) of tissue. While
the manner in which the data were collected prohibits
statements concerning actual shell growth rates, the fact
that Y-intercepts declined and increased demonstrates
active soft tissue degradation and growth, respectively,
at rates not comparable to shell growth. The slope of the
regression line describing the relationship rose markedly
in May, documenting a change in the relationship among
different size clams. Larger individuals were apparently
accumulating tissue at a rate proportionately greater than
previously observed. Smaller individuals were most likely
continuing to accumulate tissue, but the apparent re-
duction in tissue mass relative to SH probably signified
a rapid increase in rate of shell growth.

The increase in tissue mass in larger individuals ( ~ 15
mm and greater) in May was most likely in preparation
for reproductive activities, while the marked decrease in
slope of the regression line from May to June could have
reflected initiation of spawning. Reproductive effort in
this population for 1984 was greatest during June and
July (Dohert> et al., 1987). This interpretation is consis-
tent with the observations of Morton (1982). He reported
a 42?t decline in the slope of the regression line between
DW and SL for groups of Corbicula fluminialis collected
both prior to and after spawning. In contrast, Aldridge
and McMahon (1978) did not find significant differences
for regressions between log transformed variables of SL
and DW for 28 groups of Corbicula fluminea collected
over a 16-month period. The gradual reduction in slope

from June to October may have reflected a continuing
release of juveniles by adults, although the need for in-
creased energy e.xpenditure during the warmest period
of the year may have also contributed to the decline.

The changes in CRDW relative to SH for smaller clams
(~10 mm or less) between April and May were probably
a reflection of increased shell secretion rather than tissue
loss or resorption. If clams of this size were sexually
immature, they would not require a massive increase in
tissue to accommodate reproductive efforts. An overlap
of the April and May regression lines for clams ranging
in size from ~10 to 14 mm may indicate that physio-
logical activities are allocated equally to shell secretion
and tissue growth. This interpretation also suggests that
size of an individual at the time of spawning dictates the
total number of veligers released by that individual.

Increases in the slopes and Y-intercepts for November
and December could have been due to tissue growth,
resulting from an abundance of nutritive material as-
sociated with high river discharge from locally heavy
flooding (figure 1). Doherty et al. (1987) hypothesized
that high river discharges provided high levels of nu-
trients that permit more than two spawning episodes per
year while Foe and Knight (1985) concluded that sus-
pended sediments, up to a concentration of 150 mg/liter,
do not adversely affect growth of the Asiatic clam. Since
lower temperatures during these months might result in
reduced metabolic demands, the potential for growth
and maintenance of tissue mass could have been en-
hanced.

These data also support earlier observations by other
investigators that an inverse relationship exists between
growth rate and initial size of an individual (Britton et
al, 1979; Dreier & Tranquilli, 1981; Welch & Joy, 1984).
For example, a 6-mm (SH) juvenile had a dry weight of
2.7 mg in February, whereas the dry weight of an in-
dividual of similar shell size had a dry weight 154%
greater in April. The increase in tissue mass for a 20-
mm (SH) adult was only 68% between February and
April (59 and 99 mg dry tissue weight, respectively).

Similarly, the magnitude of the difference between
regression lines between any two months is unequal,
supporting observations by other investigators that growth
is seasonally influenced. Both Fuji (1957) and Joy (1985)
observed no growth (SL) in clams maintained at water
temperatures <10°C. Measurable growth was observed
when temperatures rose above 14 °C, while the greatest
rates of growth were observed at 24 to 30 °C. Britton et
al. (1979) reported a slowing of shell deposition in clams
with shell >10 mm in length during winter, while
McMahon and Williams (1986) found growth rates of
Corbicula fluminea individuals to be characterized by
large seasonal variation. Mattice and Wright (1986) ob-
served varying growth rates for the Asiatic clam in field
studies and suggested that temperature played a major
role in growth determination. These conclusions, though,
were formulated from observations of shell growth rate.
Our study demonstrates that growth of tissue can occur
at temperatures below those which appear to be necessary

Page 14

THE NAUTILUS, Vol. 104, No. 1

for measurable increases in sliell height, length, or infla-
tion (February to April; October to November; table 2).
Russell-Hunter et at. (1984) have reported comparable
observations for populations of freshwater puimonate
snails. Comparisons between pre- and post-winter sur-
viving individuals of Helisoma trivolvis and Lijmnaea
palustris revealed reductions in soft tissue ranging from
19-169% ba.sed on predictive equations between shell
and tissue ma.ss for pre-winter snails.

This study demonstrates that shell growth as defined
bv increases in shell height, length, or inflation is not
equivalent to, and does not necessarily parallel, tissue
growth. Initial size, reflective of the reproductive ma-
turit\' of an individual, and season, reflective of temper-
ature and food availability among other things, are pos-
sibK' major factors in determining whether shell or tissue
growth will predominate. These data imply that regres-
sions between a shell dimension and soft tissue mass gen-
erated at one time of the year are not applicable to the
same population in other months or seasons.

ACKNOWLEDGEMENTS

This research was funded in part by a grant from Amer-
ican Electric Power Company and a Cunningham Dis-
sertation Year Fellowship awarded to the senior author
by Virginia Polytechnic Institute and State University.
Water temperatures and discharge rates for the New
River were provided by R. Roy (Celanese Corporation)
and H. Williams (United States Geological Survey), re-
spectively. Appreciation is extended to J. Grudzien for
drafting the figures, to Daria Donald for editorial assis-
tance, and Betty Higginbotham for typing the final draft.

LITERATURE CITED

Aidridgf, D W and K V McMahoii 1978. Growth, fecun-
dity, and bioeneri^etics in a natural population of fresh-
water clam, Corhinilu riuinilrnsis Pliilippi, from North
Central Texas. Journal Molluscan Studies 4^:49-70

Belanger, S. E., 13. S. Cherry, and J Cairns, Jr. 198(ia. Sea-
sonal, behavioral, and growth clianges of juvenile Corl/ic-
ula fluminea exposed to chrysotile asbestos. Water Re-
search 20:1243-1250.

Belanger, S. E., J. L. Farris, I). S Cherry, and J Cairns, Jr
19S6b. Growth of Asiatic clams (Corlnrtda sp ) during
and after long-term zinc exposure in field-located and
laboratory artificial streams. Archives Eru ironmenlal ( loii-
laniination Toxicology 15:427-4.34

Brilton. J C. and B Morton. 1982 A dissection guide, field
and laboratory manual for the introduced bivalve Corlric-
ula fluminea. Malacological Review Supplement No. 3.
82 p.

Brilton, J. C, D. R C;oldiron, L. P. Evans, Jr., C. Golightlv, K.
D O'Kane, and J. R. TenE\ck 1979. Reevaluation of
I Ik- growth paltern in Corbkula fluminea (Miiller). In:
liritlon, J (; (ed.). Proceedings of the First International
Ciirlnnila Svniposium. Texas Christian University Rc-
scarcli 1-oiindalion. IVjrl Worth, TX, p. 177-192.

Butlner, J K l')8B Biology of Corbicula in catfish rearing
ponds In: Brill. .n. J C (ed.). Proceedings of the Second

Inlernalional C'orhicula Symposium .Xmerican Malacol-
ogical Bulletin Special Edition No. 2:211-218.

Dauble, D. D., D. S. Daly, and C. S. Abernathy. 1985. F"actors
affecting growth and survival of the Asiatic clam, Corbic-
ula sp., under controlled laboratory conditions. In: Card-
well, R. D., R. Purd\ and R C. Bahner (eds ). Aquatic
Toxicology and Hazard Assessment: Seventh Symposium.
STP 854. American Societv for Testing and Materials,
Philadelphia, p 1.34-144.

lioherty, F G., D S. C^herry, and J. Cairns, Jr 1987 Spawning
periodicity of the Asiatic clam, Corbicula fluminea in the
New River, Virginia. ,'Vmerican Midland Naturalist 117:
71-82,

Oreier. H and J. Tranquilli. 1981. Reproduction, growth,
dislribution, and abundance of Corlncula in an Illinois
cooling lake. /;i; Larimore, R W. and J. .\. Tranquilli
(eds.). The Lake Sangchris study: case history of an Illinois
cooling lake. Illinois Natural Historv Survev Bulletin .32:
378-393.

Foe, G and A. W. Knight 1985. The effect of ph\ toplankton
and suspended sediment on the growth of Corbicula flu-
minea (Bivalvia). Hydrobiologia 127:105-115.

Foe, C. and A. W Knight. 1986a. A thermal energy budget
for juvenile Corbicula fluminea. In: Britlon, J. G (ed.)
Proceedings of the Second International Corbicula S>tn-
posium. American Malacologiral liulletin Special Edition
No. 2:14.3-1.50.

¥oe, C. and A W. Knight. 1986b. .\ method for evaluating
the sublethal impact of stress employing Corbicula flu-
minea. In: Brittou, J. G. (ed). Proceedings of the Second
International Corlncula Symposium. American Malaco-
logical Bulletin Special Edition No. 2:133-142.

Foe, G and A. W. Knight. 1987. Assessment of the biological
impact of point source discharges employing Asiatic clams.
Archives Environmental Contamination Toxicology 16:.39-
51.

F'uji, A. 1957. Growth and breeding season of the brackish
water bivalve, Corbicula japonica in Zyusa-Gata inlet.
Bulletin of the Facult\ of F"isheries, Hokkaido I'niversit)
8:178-184.

Joy, J. E 1985, A 40-week stud\ on growth of the .\sian clam,
Corlncula fluminea (Miiller), in ihe Kanawha River, West
Virginia. The Nautilus 99:110-116.

joy, J. E. and L. E. McC^ov. 1975. Compari.sons of shell di-
mensions and viscera mass weights in Corbicula nianilcn-
sis (Philippi, 1844). The Nautilus 8951-54.

Keiuiedy, V. S. and L. Van Heukelem. 1985. Gametogenesis
and larval production in a population of the introduced
Asiatic clam, Corlncula sp. (Bivalvia: (-orbiculidae). in
Maryland Biological Bullelin 168.50-60.

Mallice, j S and I, D. Wright 1986. Aspects of growth of
Corbicula fluminea. .Vmerican Malacological Bulletin Spe-
cial lulition No, 2:167-178.

McMalion, R. F. and C. J. Williams 1986 .\ reassessment of
grow th rate, life-span, life-cycles and population dynamics
in a natural population and field caged individual of Gor-
bicula fluminea (Miiller) (Bivalvia: Gorbiculacea) In: Bril-
ton, J, (;. (ed). Proceedings of the Second International
Corbicula S\niposium .American Malacological Bullelin
Special Edition No, 2: 151-166,

Morton, B, 1982, Some aspects of ihe [jopulalion sirueture
and sexual strateg\ of Corbicula ef fluminialis (Bivalvia:
Gorbiculacea) Irom the Pearl River, Peoples Republic ol
China Journal of Molluscan Studies 48: 1 -23

Kodgers, J H , Jr . D S Cherry. J R Clark, K E Dickson,

F. G. Doherty et al.. 1990 Page 15

and J. Cairns, Jr 1977 The invasion of Asiatic clam, Sickel, J 1979. Population d>'naniics of Curhicula in the Al-

Corbicula manilcnsis in tfie New River, Virginia. The taniaha River, Georgia 7n. Britton, J. C;. (ed). Proceedings

Nautilus 91:43-4(1 ot the First International Corhiciila .Symposium Texas

Russell-Hunter, W D., R A. Browne, and D W Aldridge Christian Llniversit\ Research Foundation, Fort Worth, p

1984. Overwinter tissue degrowth in natural populations 69-80.

of freshwater pulmonate snails (Helisoma thvolvis and Welch, K. J. and J, E. Joy 1984 Growth rates ol the Asiatic

Lymnaca palu.slris). Ecology (55:22.3-229. clam, Corhiciila flurninea (Miiller), in tlie Kanawha River,

SAS Institute, Inc. 1982. SAS user's guide: basics, 1982 ed. West Virginia, Freshwater Invertebrate Biology 3:1.39-

.SA8 Institute, Inc., Gary, North Garolina, 923 p. 142.

Schmidt-Nielsen, K, 1984. Scaling, why is animal size so im-
portant'r* C^ambridge I'niversity Press, Cambridge, 242 p.

THE NAUTILUS 104(1): 16-25, 1990

Page 16

Geological Substrate and Human Impact as Influences on
Bivalves of Lake Lewisville, Trinity River, Texas

Raymond W. Neck

Texas Parks and Wildlife Department
4200 Smith School Road
Austin, Texas 78744, USA

ABSTRACT

The bivalve fauna of Lake Lewisville (Elm Fork Trinity River),
Denton County, Texas, consists of 16 species. Present are the
introduced Asian clam and 1,5 native unionids. Relative abun-
dances of species in different areas of the reservoir are related
to inundation history and geological substrate Inundation has
localK extirpated some species while other species ha\e flour-
ished. Utilization of shell material for the cultured pearl in-
dustry is documented. Ecological, taxonomic, and zoogeo-
graphical notes are presented for each species.

Ketj icords: Freshwater bi\aKes; Lake Lewisville; Trinity Riv-
er, faunal changes; commercial utilization.

INTRODUCTION

Little is known of the detailed distributions of the fresh-
water mussels of Texas. Two comprehensive lists have
been published (Singley, 1893; Strecker, 1931), but these
compilations are in need of updating. Even recent treat-
ments of North .\inerican unionids (Burch, 1973, 1975)
do not adequately cover the Texas fauna. The only stud-
ies of freshwater bivalves from north central Texas lo-
calities cover Lake Texoma (N'alentine & Stansbery, 1971;
White and White, 1977) and Lake ,\rrowhead (Neck,
1989b). Murray (1972, 1978) has summarized the unio-
nids present in two reservoirs in central and southern
Texas. Localized faunal surveys of freshwater bivalves
of other portions of Texas have been published recently
(Neck, 1986, 1987, 1989a; Neck ti Metcalf, 1988).

Below is a summary of a survey of the mussel fauna
of Lake Lewisville, a reservoir in north central Texas on
the Elm Fork of the Trinity River (figure 1 ). The purposes
of this survey were to determine relative abundance of
resident species, intra-reservoir distributions of various
species, and human impact upon this fauna. Justifications
for the nomenclature used are provided where proper
usage has been unclear; nomenclature follows Turgeon
pl al. (198S).

Previous reports of freshwater bivalves from the upper
Trinity River drainage have been published. Flook and
Ubelaker (1972) reported nine species from a single lo-
cality in Lake Lewisville. Strecker (1931) reported four-

teen species from the Elm Fork of the Trinity River
"near Lewisville, Denton County. The naiad fauna of
Dallas County (which borders the southern edge of Den-
ton County) was studied by Read (1954; Read & Oliver,
1953). A survey of unionids of several reservoirs of Tar-
rant County (Fort Worth, to the west of Dallas County)
is available (Mauldin, 1972).

STUDY AREA

Lake Lewisville (figure 2) is located in north central
Texas in central Denton County, approximately 24 ki-
lometers southeast of Denton and 35 kilometers north-
west of Dallas. Impounded watercourses include the
mainstem and lower reaches of some tributaries of the
Elm Fork of the Trinity River. The Elm Fork of the
Trinity River is formed from the coalescence of many
small tributaries in Cooke, Montague, Clay, and Archer
Counties to the west of Denton County.

Lake Lewisville has a dual history; information below
is from Dow ell and Breeding (1967). The original im-
poundment (Lake Dallas) was created by Garza Dam
built during 1924 through 1927; deliberate impound-
ment of water began 16 February 1928. The area of the
original impoundment was 44.5 km- at spillway eleva-
tion. Original capacity was 2.4 million cubic meters
(drainage area 3,018 km-). Accumulation of sediment
became a severe problem in the original Lake Dallas. By
1952, capacity of the reservoir had decreased 19.3% to
1.9 million cubic meters. Hydrochemical and vegeta-
tional conditions of Lake Dallas were reported by Harris
and Silvey (1940).

Construction of a second dam downstream near Lew is-
ville was begun in November 1948 and completed in
.■\ugust 1955. Impoundment of water began 1 November
1954. Following a prolonged filling period during a se-
vere drought, a passageway was created through Garza
Dam on 28 October 1957. The combined reservoir system
has a surface area of approximately 94.28 km- at con-
servation pool level (156 meters above mean sea level).
Surface area of the flood pool (161 m msl) is 158.17 km^.
Capacity of the combined reservoir system is 5.7 million
cubic meters at conservation ()ool and 12.2 million cubic

R. W. Neck, 1990

Page 17

Lake
Bridgeppr t

.^Lahe Ray Roberts

Lake Lewisville

Lake Lavon

Grapevine Lake

Lake Ray Hubbard
Cedar Creek Res.

Lake Worth
Benbrook Lake

Lake Arlmgtor)
Mountain Creek Lake

Navarro Mills Lake

Fairfield Lake

Lake Livingston-

TRINITY RIVER DRAINAGE

Houston
County
fles

Lake Anahuac -

Figure 1. Mali "f TriiiiU Knci drainage, Texas, showing
location of Lake Lewisville and other reservoirs.

LAKE LEWISVILLE

Figure 2. Map of Lake Lewis\ ilie, Texas, showing geological
snlistrate, reservoir subdivisions (Roman numerals), and col-
lecting localities (Arabic numbers;.

meters at spillwav level. Drainage area above the dam
is 4,300 square kilometers. Shoreline of the conservation
pool is appro.ximateK 295 kilometers. Primary purposes
of the reservoir are flood control, municipal/industrial
water supply, and recreation.

More recentK Smith (1973) studied the physicochem-
istrv of Lake Lew is\ ille. Nariation in water phv siochem-
ical parameters was found to be due more to the original
characteristics of the basin rather than the length of
impoundment. Algal species composition was fairly uni-
form throughout the surveved portions of the reservoir.
Water temperature varied seasonally from 5.0 °C to 28.5
°C and pH varied from 7.3 to 8.4. Alkalinit)' varied from
90 to 107 mg/L (mostly bicarbonate) for area II and
from 116 to 151 mg/L for area I. Nitrate levels varied
from 0.354 to 3.588 mg/L, while phosphate levels ranged
from 0.017 to 0.165 mg/L. The Lake Dallas basin (area
I) had greater turbiditv' and higher nutrient enrichment
(phosphate and bicarbonate) than area II.

This reservoir has suffered from a lack of name stan-
dardization. Originally both the combined impound-
ment and the dam structure were known as Garza-Little
Elm Reservoir and Garza-Little Elm Dam. In 1955 the
name of the dam was changed to Lewisville Dam al-
though the reservoir name was unaltered Subsequently
the U.S. Army Corps of Engineers (which operates the
dam and reservoir) has changed the name of the reservoir
to Lake Lewisville.

The surface geology of the area covered by Lake Le-
wisville is rather simple (VVinton, 1925). The eastern
portion is underlain bv the Eagle Ford Formation and
alluvial deposits, whereas the western portion is under-

lain by the Woodbine Formation and limited alluvial
areas. All deposits are Upper Cretaceous except for the
Pleistocene and Recent alluvial terraces. The Eagle Ford
consists of a series of black oily shales with a few thin
ledges of sandstone. The Woodbine is somewhat variable
( Winton, 1925); several lavers of indurated sandstone are
separated by softer sandstone, loose sand, and clav' layers.
The Eagle Ford /Woodbine contact is aligned approxi-
mately along a NNE to SSW line and passes very close
to the axis of Garza Dam, w liich formed Lake Dallas.

Climate of the studv area is transitional between mar-
itime-subtropical and continental-temperate. The near-
est recording weather station is at Denton, where the
average monthly temperature varies from 7.2 °C in Jan-
uary to 29.3 °C in .\ugust. Extreme temperatures re-
corded are 45 °C and —19.4 °C. Annual precipitation
averages 804 mm, but has varied from 384 mm in 1963
to 1,433 mm in 1957. The growing season is 226 days
(27 March to 8 November). Weather records for any
particular year often are far from the mathematical
"norms" because this region is characterized b> dramatic
year-to-year fluctuations. Fluctuations in precipitation
usually are larger than those in temperature. Major
droughts occurred in the 1930's and 1950's.

Drought during the mid 1950's was severe enough that
1.2 million cubic meters (98,470 acre-feet) of water were
diverted from the Red River into Lake Dallas. Water
was pumped from the Red River in Cooke County into
Pecan Creek through which the water flowed by gravity
into the Elm Fork of the Trinitv River (Dovvell & Breed-
ing, 1967:36).

Page IS

THE NAUTILUS, Vol. 104, No. 1

METHODS

Twelve survey sites (Appendix) were chosen in a manner
that all major areas of the reservoir were sampled. Most
of the sites were located in various recreation parks built
by the U.S. Army Corps of Engineers. Time of sampling
activities (Winter 1977 through Fall 1978) coincided with
an extended drought, which resulted in substantial low-
ering of the reservoir level. Many hectares of reservoir
bottom were exposed to air. Bivalve shells were extremely
abundant and readily counted.

Survey transect areas were four meters wide along the
water edge for varying distances. Length of transects
varied from 50 to 70 meters, but some were lengthened
be\ond 70 meters in order to increase sample number.
Counts should not be taken as relative densities, but as
estimates of relative species occurrence at particular sites.
Only paired valves were counted in order to reduce the
effect of water movement of "dead" valves to localities
unsuitable for the species. Such movement is believed to
be of minimal significance because most valve pairs lay
in situ, partialK' covered with sediment at the place of
death. .After counts along the pre-selected transect were
completed, additional lengths of adjacent reservoir edge
were walked. Additional species at times were added to
the list of species occurring at a given sampling area.
Such occurrences are not recorded in the relative counts
for a particular site (tables 1 and 2).

Representative specimens collected during this study
have been deposited in the Dallas Museum of Natural
Historv.

BIVALVE FAUNA

A total of 16 species were observed at the various sam-
pling stations around the reservoir shore (table 1). All
but one, Corhicula fluminea, are native members of the
Unionidae. No fingernail or pea clams (family Sphaeri-
idae) were observed during this study. Below is a list of
species recovered from Lake Lewisville with nomencla-
torial discussion, publisheil haliitat notations, and habitat
occurrences in Lake Lewisville.

Corbicula fluminea (Miiller, 1774) was not abundant
in Lake Lewisville; no living specimens were found. Fa-
vorable habitat areas (moving water over sand or gravel
substrate) were in small creeks feeding into the reservoir.
A few young shells (7 mm length) were found on sand
at Fish-O-Hama (private commercial development). All
specimens from Lake Lewisville were referable to the
"white form" (Hillis & Patton, 1982).

Anodonta grandis Say, 1829, is an extremely variable
taxon as several names have been applied to different
phenotypes. Read (1954) reported this species to be the
'most abundant and widely distributed species in Dallas
Coimty, ' but referred his specimens to A. corpulcnta
'-('opei. 1S.'34; Strecker (1931) called all specimens A.
taaudus Lake Lewisville specimens tended toward the
corpuhnln phuiiolype (largest specimen measured 148.3
mm in slieli Irngth). A. grandis was a common species

in Lake Lewisville; 106 specimens were taken, and all
12 reservoir localities were represented (table 1).

Anodonta imbecillis Sa\, 1829, occurs in the eastern
United States, throughout the entire Mississippi system,
and southward through the Gulf drainages into Mexico
(Simpson, 1914:396; Burch, 1975:15). Mauldin (1972) re-
ported A. imbecillis to be more frequent in ponds and
small reservoirs than in large reservoirs. Only 18 indi-
viduals of A. imbecillis from 8 scattered localities were
found in Lake Lewisville (table 1). Anodonta imbecillis
probably was more abundant in backwater sloughs and
pools of small creeks that drain into Lake Lewiss ille.

Arcidens confragosus (Say, 1829) is distributed
throughout the Mississippi drainage (Murray is. Leonard,
1962). In Dallas Co., Read (1954) found A. confragosus
only in Parson's Slough in shallow water with a "fair
current " over a mixed sand and mud substrate. This
species was found at 9 reservoir localities, but only 16
individuals appeared in 7 transects (table 1).

Amblema plicata (Say, 1817) was the most abundant
naiad in Lake Lewisville; 624 specimens (38.8% of total)
were counted at 12 transect locations (table 1). This species
was the most abundant bivalve at all locations. Amblema
plicata occurs throughout much of eastern North Amer-
ica, south to the Nueces River, Texas (Burch, 1975). A
number of taxa have been established for the A. plicata
complex in the United States. Read (1954) reported both
A. costata Rafinesque, 1820, and A. perplicata (Conrad,
1841) from the Elm Fork of the Trinity River in Dallas
County. Flook and Ubelaker (1972) recorded both A.
plicata and A. costata for Lake Lewisville, but only 4 of
150 were referred to A. costata. These two forms are
believed to be either genetic morphs or ecophenotypes;
in either case no taxonomic rank is recognized herein.

Quadrula mortoni (Conrad, 1834) is restricted to the
eastern half of Texas (Strecker, 1931). This species is
represented in Lake Lewisville by pustulate and non-
pustulate forms, which are known from reservoirs in
neighboring Tarrant County (Mauldin, 1972). Some of
the less angulate specimens, particularly those with a
large number of pustules, approach Quadrula pustulosa
(Lea, 1829). However, specimens similar to Q. pustulosa
from Lake Lewisville differ from Q. pustulosa from
southeastern Texas in general shape of shell as well as
number, form, and arrangement of pustules. Specimens
of Q. mortoni differ from Q. pustulosa by being broader
and somewhat flatter along the dorsal portion of the
valves. Individuals of Q. mortoni (pustulate and non-
pustulate) in Lake Lewisville are most abundant on a
sand substrate, even if the sand exists only as a shallow
bar over bedrock shale (as in area II).

Shells referred to t\ pical Q. mortoni in this stud) can
be keyed to Q. houstonensis (Lea, 1859) b\ using Read
(1954), who reported the latter taxon to be "not common
in Dallas County," from Elm Fork of the Trinity River
on gra\el bottom in about a meter of water. Strecker
(1931) noted, however, that Q. houstonensis from the
Elm Fork near Lewisville was "rather inflated and seems
peculiar to this branch of the Trinity." Examination of

R. W. Neck, 1990

Page 19

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Page 20

THE NAUTILUS, Vol. 104

, No. 1

Table 2. Relative counts and percentages

of bivalves

of Lake

Lewisville and

subdivisions

III

Total

r;**

'■;

Corbicula fltiminea

—

0.6

0.2

Anodonia grandis

5.4

6.2

/ - /

106

6.5

Anodonta imliecilis

1.3

0.9

1.3

1.1

Arcidens confragosus

1.3

0.2

1.9

1.0

Aniblema plicala

128

42.8

301

37.5

195

37.6

624

38.5

Quadrula morttmi

1.0

0.8

Qiiarida apictilala

27.8

116

14.5

15.8

281

17.3

Tritogunia verrucosa

—

Lampsilis hiidiana

4.3

124

15.5

14.8

214

13.2

Lampsilis satura

—

Lampsilis teres

2.0

6.2

3.9

4.7

Leplodea fragilis

4.6

4.4

3.9

Polarrtdus amphichaenus

2.0

2.5

Potamilus purpura! us

8.7

5.4

3.7

5 4

Toxolasma parvus

—

0.7

—

0 4

TrunciUa truncata

3.3

4.6

4.2

4.3

Si^ecies

—

Individuals***

299(13)

—

802(14)

—

519(12)

—

1,620(14)

—

% of Total Sample

18.5

—

49 5

—

.32 0

—

100,0

—

* Present, but not recorded in transect.
** % of transect sample
*** N'imiber in parentlieses is number of species present in transect.

shells at the Streckcr Museum (SM) from the Elm Fork
near Lewisville identified as Q. houslonensis by Strecker
(SM 325-329) revealed shells of Q. pustulosa that are
somewhat more ciuadrate than typical Q. mortoni. No
such shells were found in the present survey. Examina-
tion of other shells referred to Q. houslonensis by Streck-
er revealed robust shells that appear to represent several
species of Quadrula.

Quadrula nodulata (Hafinesque, 1S20) has been re-
ported from various portions ot eastern Te.xas (Strecker,
1931). A single specimen that resembles Q. nodulala was
found in Lake Lewisville in transect samples. Exami-
nation of specimens from Lake Lewisville that resemble
Q. nodulata indicated that these shells were Q. mortoni.
These Lake Lewisville specimens did not exhibit nodules
on the posterior ridge as in typical Q. nodulata; nodules
are restricted to the middle of the shell (below the umbo
area).

Read (1954) reported Quadrula metanevra (Hafin-
esque, 1820) from adjacent Dallas County. These shells
may have been these nodtdala-]\ke shells or an extremely
angulate Quadrula apiculata.

Quadrula apiculata (Say, 1829) ranges from the Rio
Grande through all Texas streams to the .\labama River
( Xeel, 1941). The southern maple-leaf mussel is the sec-
ond-most abundant naiad species in Lake Lewisville; 281
individuals were taken at all 12 sites (table 1). Read
I HJ.J4) rcpiirtcd two phenotypes in Dallas County in-
cluding l"lm Fork below the present Lake Lewisville: 1)
"specinsu [.( 1, 1 sfi2" with pustules extending to the ven-
tral margin, and 2 "for.sheyi Lea, 1859" with pustules

only on the more dorsal portions of the valves. Read
(1954) reported that both forms prefer sand bottoms;
"speciosa" tended to be found in shallow water while
"forsheiji" tended to be found in fairK- deep water. These
morphological tvpes represent genetic variation in the
Q. apicidata population, but they ma> also be the result
of reduced rates of pustule formation in older individuals.
Neel (1941), who treated apiculata as a form of Quadrula
quadrula (Rafinesriue, 1S20), presented a discussion of
the iorms of the Q. quadrula group.

Tritogonia verrucosa (Rafinesque, 1820) has a wide
distribution throughout the Mississippi drainage and oth-
er Gult coastal tlrainages from Georgia to Texas (\'al-
entiiie & Stan.sbery, 1971). In Dallas County, Read (1954)
found it only in Elm Fork, where it was "perhaps the
most abundant species," on hard gravel or sand in fairly
deep water in sw ift current This species most often has
white nacre; pink and purple nacres become more com-
mon in the southern part of its range according to Val-
entine and Stansbery (1971), who found few specimens
in Lake Texoma (all of which had white nacre). All
specimens located in this study have white nacre. This
spe'cies is extreme!) uncommon in Lake Lewisville; no
specimens were encountered in the transect censuses (only
one specimen was found, at Graveyard Slough, which is
near an incoming creek, w hich would "freshen" the water
i)ualitv ) The raritv of T. verrtico.sa in Lake Lewisville
is the result ol its requirement for a rapid current of
water.

Lampsilis hydiana (Lea, 1838) ranges from eastern
Texas and Oklahoma eastward to Arkansas and Alabama

R. W. Neck, 1990

Page 21

(Uurcli, 1973:2U). L. hijdiana was reported rare in Dallas
County by Read (1954), who found it only in Elm Fork.
L. hijdiana is the third most abundant mussel in Lake
Lewisville (but is not common in Area 1); a total of 213
individuals were counted in 12 transects (tables 1, 2).
Shells exhibit phenotypic variation in details of structure
of the pseudocardinal teeth, but this variation tends to
be ontogenetic (changing with age). Rays are absent,
present on the entire shell, or restricted to the posterior
half. Rays may be single and narrow (about 0.1 mm
wide) or may coalesce into stripes (whose widths ap-
proach 3 mm). Spacing between rays varies such that
80*^0 of the periostracum may be greenish in contrast to
the yellowish horn color of the background. Variation in
shell morphology may reflect genetic influence by Lamp-
silis luteola (Lamarck, 1819), a species that ranges
throughout all of the Mississippi River and southern Can-
ada east of the Rock\ Mountains (Burch, 1973:21); /;/-
teola intergrades with hijdiana in Louisiana and southern
Arkansas (Stansbery, 1983).

Lampsilis satiira (Lea, 1852), the southernmost species
ot the Lampsilis ovata (Say, 1817) group, is restricted to
westernmost Louisiana and eastern Te.xas (D. H. Stans-
bery, personal communication). A single shell was found
in Lake Lewisville at station 7 (table 1). This specimen
is small (47.6 mm, shell length) and had been dead for
several years before reco\er\. The umbo is somewhat
higher than those of most L. satura from eastern Texas.
The recovered specimen probably represents a remnant
population (possibly now extirpated) adapted to a free-
flowing stream. Read (1954) reported Lampsilis vcntri-
cosa (Barnes, 1823) as rare in Dallas County; this record
probably refers to L. satura.

Lampsilis teres (Rafinesque, 1820) was reported b\
Read (1954) as being not ver\' abundant in Dallas Count\
on soft mud substrate, but found in the side of a tight
mud bank. Lampsdis fallaciosa Smith, 1899, has been
utilized to refer to a smaller form with greenish rays (not
found in Lake Lewisville but found in Elm Fork below
Lewis\ille Dam during this stud\ ). \alentine and Stans-
bery (1971) suggested that Lampsilis fallaciosa may have
been replaced by L. teres in Oklahoma during the twen-
tieth century after they compared their contemporary
collections with those of Isely (1924). White and White
(1977) reported the two forms from Lake Texoma in
similar habitats but in different arms of the reservoir. L.
teres was found at every locality sampled in this study;
a total of 76 individuals were counted in 11 transects
(table 1).

Leptodea fragilis (Rafinesque, 1820) occurs through-
out most of the eastern United States (Valentine & Stans-
bery, 1971). Read (1954) found L. jragilis widely dis-
tributed in Dallas County in soft sand and muck. L.
fragilis was found at all 12 of my sample sites although
only 63 individuals were found in eleven transects (table
1). This species was more abundant on sand than on clay
substrates, although 1 found L. fragilis in mud at the
base of a terrace cutbank in moving water in the Elm
Fork above Lake Lewisville.

PotamUus ainphichaenus (Frierson, 1898), is known
from the Brazos, Trinity and Sabine Rivers of Texas and
westernmost Louisiana (Strecker, 1931). Despite Frier-
son's (1898) statement that P. amphichaenus was "one
oi the most distinct and remarkable Unios, this taxon
is little known today. Specimens of P. amphichaenus
from Lake Lewisville can be separated from specimens
of Potamiliis ohicnsis (Rafinesque, 1820) from the Red
River to the north by the following characters of P.
amphichaenus: 1) less compressed laterally; 2) more
prominent sinus in the posterior portion of the pallial
line; 3) prominent umbo scars; 4) much lower wings,
anteriorly and especialK' posteriorly; 5) large gape be-
tween the valves, especialK anteriorly; and 6) decreased
prominence of pallial line anteriorly.

Potamilus purpuratiis (Lamarck, 1819) occurs in
streams from western Tennessee to Kansas, southward to
Louisiana, w here it is more common in downstream sites
(Valentine & Stansbery, 1971). Read (1954) found it
abundant in Elm Fork on gravel, hard clay, mud, and
sand. P. purpuratiis is the fifth most common naiad in
Lake Lewisville; 88 specimens were counted in 12 tran-
sects, and presence was noted in two additional sites.

Toxolasma parvus (Barnes, 1823) is the smallest unio-
nid found in this area. T. parvus is found in streams from
New York to the Dakotas, southward to Texas and Al-
abama (N'alentine & Stansbery, 1971). Live specimens
from Lake Texoma were found on silt or soft mud in
areas protected from v\ ind disturbance (White and White,
1977). Read (1954) found T. parvus widely distributed
in Dallas County on mud bottoms in shallow ponds and
sluggish streams. The largest T. parvus that I have seen
from Lake Lewisville were 24.9 mm in length. Only six
individuals were found at three transects; additional
specimens were found at three other sites. T. parvus is
a monomorphic (presumabK' monoeicious) species in
comparison to the larger, dimorphic (presumably dioe-
cious) Toxolasma texasensis (I. Lea, 1857), a species not
known from Lake Lewisville.

Truncilla truncata Rafinesque, 1820, is known trom
the Mississippi River drainage and westw ard into eastern
Texas (Strecker, 1931; Burch, 1973). T. truncata was
reported from Elm Fork on soft mud, but occasionally
in gravel and sand (Read, 1954). Color of periostracum
of Lake Lew isville specimens varies from \ ellow ish brown
to dark brown; a few specimens have narrow, faint rays.
Sixty-nine individuals were collected from 11 transects.

The bivalve fauna of Lake Lewisville as recorded in
this survey consists of 16 species (one corbiculid and 15
unionid species). Amhicma plicata is the most numerous
species at all 12 sampling localities and includes well
over one-third of the individuals counted. The seven most
abundant species in the transects comprise 89.9% of the
sample. The seven least common species comprise the
remaining 10. 1 % of the sample. Seven species were found
at all 12 sampling sites; 1 1 species, 9 or more sites. Except
for the two species found at only a single locality, all
species were found at fi\ e or more sites. No site contained
all species, but all sites had at least nine.

THE NAUTILUS, Vol. 104, No. 1

DISCUSSION
Zoogeography

The unionid fauna present -Lake Levusville is typical
of the West Gulf Province (Hoback et al 1980, Neck,
198'7a) which includes the area drained b> rivers west
and'south of the Mississippi River from the Sab.ne system
through the l\.o Grande System. The Trinity Hjver drain-
age luts the Miss>ssippi drainage just north of Lake
Lewisvilie, where the Red and Trinity Rivers are sepa-
rated bv a low divide. Little or no recent f aunal exchange
haf occurred because of the very 'i-J^d "umber of
mussel species in the Red River. Along the Coastal Plain
Se drainages of the Trinity and the Red are separated
by the Sabine/Neches system.

\he species present in Lake Lewisvdle represent the
•upland" component of those species present in the Trin-
ity River Strecker (1931) recorded several species in the
lower Trinity (but not the Elm Fork) that are not present
in Lake Lewisvilie, because the pre-impoundmen con-
ditions of the Elm Fork were not suitable for such large-
stream or sand-substrate forms. Species included are
StrophUis undulatus (Say, 1817), Fusconma cenna
(Conrad, 1838), Megalonaias nervosa (Rafmesque, 1820),
Plcctomerus domheyanus (Valenciennes, 1827), Irun-
cUla donaciformis (I. Lea, 1828), and Truncilk macro-
don (1. Lea, 1859).

INTRA-RESERVOIR DISTRIBUTIONS

Lake Lewisvilie can be divided into three major subdi-
visions, which are based upon natural and artificial en-
vironmental factors (figure 2). Area I consists of the orig-
inal Lake Dallas; this area is underlain by the Woodbine
Formation. The substrate presently consists of silty clays
which have been deposited over the past 50 years. This
area receives sewage outfall from the city of Denton
(1980 population-48,063) and probably several small
towns farther upstream. Area II consists of the larger
part of the new reserxoir portion of Lake Lewisvil e
which is underlain by thm silty clay terraces that mantle
the Eagle Ford Formation (shale). Area III is the Hickory
Creek Arm of the new lake portion, which is underlain
by the Woodbine Formation. Substantial portions of this
area maintain sandy substrates although the upper reach-
es are covered by recently deposited sediments.

The Denton County soil survey provides mtormation
concerning soils now covered by Lake Lew^isvil e (Ford
& Pauls 1980). Soil types presently inundated by the
original Lake Dallas (area 1) include Callisburg fine sandy
loam Gowen clay loam, and Navo cla> loam. Soils pres-
ently under area II include Altoga silty clay Ferns-Hei-
den'clays, and Heiden clay. Area III inundates Bastrop
fine sand%- loam, Birome-Rayex-Aubrey complex (sands),
Callisburg fine sandy loam, and Crockett fine sandy loam.
Examination of the data concerning relative percent-
ages of species in the three major subdivisions of Lake
Lewisvilie indicates that areas II and III are more siniilar
to each other than either is to area I (table 2). This

relationship indicates that, as a factor in thi '^^^ s di
tribution, similar period of impoundment (11 and 111) i
more important than similar geological substrate (I and
111) \lso important is unrestricted water and organism
movement between II and III whereas an old dam struc-
ture with a narrow breach exists between and I; no
direct connection exists between I and III. Shallower
water depths and decreased water quality in area I may
be additional factors.

Except the stream species that are found onh near
creek entrances and probably do not reproduce within
the reservoir {Lampsilis satura and Tritogonia verru-
cosa), no species are restricted to only one of these hree
subgroups. However, as indicated above, area I stands
well apart from the other two in terms of f aunal com-
position. For example, the two most com'^^"" ""T't
in Lake Lewisvilie (Ambler^ia plicata and Quadrula
apiculata) together comprise 55.8% of the entire fauna^
and the corresponding values for areas II and HI are
comparable (53.0% and 53.4%, respectively), but m area
I these two species comprise 70.6% o the fauna. Area
supports the least diverse fauna and is the area mos
dominated by species that are tolerant of environmental
disturbance by humans. ,. ^u -J

In contrast to dominance by abundant taxa, the third
most common species, Lampsilis hydiana is distinctly
least common in area I. The other species that are least
abundant in area I are Anodonta grandis Lampsilis
teres Leptodea fragilis, Potamilus amphichaenus and
Truncilla truncata. Potamilus purpuratus is distinctly
most common in area I. Arcidens confragosus is more
common m areas I and III than in area II; this distribution
pattern indicates a preference for sandy substrates, pos-
sibly in inflowing streams. Rare in all areas are Quadrula
mortoni. Anodonta imbecilis. Toxolasma parvus, and
Corbicula fluniinea. .

More individuals and more species occurred in areas
with clav rather than sand substrates in Lake Lewisvilie,
although a few species are more abundant on sand sub-
strates (L.'pf odea /ragi/«, Quadrula mortoni, Arcidens
confragosus, and Tritogonia verrucosa) Domination ot
the fauna by one or two species was frequent in clay
substrates and rare in sand substrates. Such relative abun-
dance relationships were also observed at several sites in
area II where well-developed sand bars overlay shale
bedrock Within areas of clay substrate, uniomds were
more common on sites with exposure to wave action.
Small sloughs in these areas seldom supported more than
a few bivalves.

Faunal Change

Several species reported from the Elm Fork by Read
(1954) were not found in Lake Lewisvilie. Obhquaria
reflexa Rafinesque, 1820, is a species that requires hard
substrates and moderate to fast currents (mqtuma re-
flexa was reported from Lake Texoma (White k White,
1977) oiiK- in riprap grasel substrate and substantial wmd-
generated xvater movement; this was the onK riverine

R. W, Neck, 1990

Page 23

species found in Lake Texoma. I have found O. rcflcxa
in the Elm Fork, below Lewisville Dam; isolated indi-
viduals could survive in localK favorable micro-habitats
within Lake Lewisville, but periodic drought conditions
reduce reservoir elevation and feeder creek flows to such
low levels that survival of O. reflexa is unlikely

Only two unionid taxa reported by Strecker (1931)
from the Elm Fork at Le\\ isville were not found during
this survey. His Qiiadrula houstonensis apparently rep-
resented shells referred to Qiiadrula mortoni in this study
(see previous discussion). Read (1954) reported Strecker's
Fiisconaia flaia uiulata to be rare in Dallas County, and
found only in the southeastern section. Several other
species were reported b\ Read (1954) in Dallas County,
i.e.. Lasmigona costata (Rafinesque, 1S20), Ohovaria
subwtunda (Rafinesque, 1820), Pleurobema cordatum
(Rafinesque, 1820), Qiiadrula meianevra (Rafinesque,
1820) and Qiiadrula petrina (Gould, 1855). These species
are not known to have occurred anywhere in the Trinity
River; these records appear to represent misidentifica-
tions.

Two species not recorded for the Trinitv Ri\er at Lew-
isville by Strecker (1931) have established populations in
Lake Lewisville. These species are Anodonta grandis
and Anodonta imbecillis; the former has become the
fourth most common bivalve in Lake Lewisville. Increase
in abundance of these Anodonta has been reported by
Murray (1982). Causes of this expansion are not under-
stood but probably invoke emploving a large number
of fish species as hosts during the glochidial stage of the
unionid life cycle (Trdan iT Hoeh, 1982). Read (1954)
suggested that fish stocking activities "probabK contrib-
uted some species . . . since Strecker," but offered no
supporting evidence. Changes in the bivalve fauna of
this reservoir are similar to those faunal alterations ob-
served in Lake Springfield, Illinois (Parmalee, 1955; Klip-
pel & Parmalee, 1979).

Human Utilization of Fauna

An additional human impact upon the unionid fauna of
Lake Lew isville was observed during this survey. L'nion-
id valve material is being utilized in the cultured pearl
industry. The high-purity calcium carbonate of unionid
shells (Nelson et al., 1966) is formed into spheres to
provide large "seeds" for cultured pearls (Peach, 1983).
In August 1978 individual shell collectors were being
paid twenty cents a pound (total wet \\ eight of shell and
animal) for shells of Amblcma plicaia and Qiiadrula
apiculata. At least one collector sold 500 kilograms (1,100
pounds) in a single day. The preferred species was A.
plicata. which had to measure about 125 mm in length
and could not exhibit worn periostracum on the ridges.
Only Amblema plicata from the "new lake" (areas II
and III in discussion below) were acceptable as shells
from the "old lake" (area I) had thin layers with black
or purple coloration. Amblcnm plicata from the "old
lake possessed thinner shells than those from other por-
tions of Lake Lewisville, shell material was often heavily

sufiused with purple, and shells with white nacre did not
possess the bright white nacre seen elsewhere in the res-
ervoir. Stansber\ (1971) found that young A. plicata on
fine substrates (similar to silted portions of the "old lake"
bed) grew more slowly than A. plicata on coarse sub-
strates.

Individual collectors were experiencing the effects of
resource depletion as suitable unionids were "becoming
hard to find." Lhiionids in some isolated coves were rea-
sonably safe from collection, but some collectors used
boats to get to these sites. Most collectors gathered union-
ids in water that was less than two meters deep. Unionids
were located visually or tactilely (\\ ith hands or feet). In
deeper water, diving equipment was used. Neck (1982b)
reported amounts of shell removed from various Texas
reservoirs, including Lake Lewisville. The 500 kilograms
of A. plicata reported above consist of approximately
1,430 animals with an average weight of 350 grams.

ACKNOWLEDGEMENTS

I thank R. W. Fullington for his field assistance, en-
couragement, and general introduction to the intriguing,
challenging, and befuddling world of unionids. Discus-
sions w ith D. H. Stansbery were useful in understanding
the complex problems in determining proper nomencla-
ture.

LITERATURE CITED

Burch, J B. 197,3. Freshwater unionacean clams (Mollusca:
Pelecvpoda) of North America. Biota of Freshwater Eco-
s> stems, Identi. Man. II, U.S. Eiivi. Pro. Agency, 176 p.

Burch, J. B. 197.5. Freshwater unionacean clams (Mollusca:
Pelecypoda) of North America, revised ed. Malacological
Publications, Hamburg, Michigan, 204 p.

Dou f 11, C. L. and S. D. Breeding. 1967. Dams and reservoirs
in Texas. Texas Water Development Board Report 48,
267 p.

Flock, J. M. and J E. L'belaker. 1972 A survev of metazoan
parasites in unionid bivalves of Garza-Little Elm Reser-
voir, Denton Oiuntv , Texas. Texas Journal of Science 2.3:
.381-392.

Ford, A and E. Pauls. 1980. Soil survey of Denton County,
Texas. U.S. Department of Agriculture, Soil Conservation
Service and Texas .-Agricultural Experiment Station, Wash-
ington, DC, 160 p.

Frierson, L. S. 1898. Unio (Lampsitis) aniphichacniis. n. sp.
The Nautilus 11:109-110.

Harris, B. B. and J. K. G. Silvey. 1940 Limnological inves-
tigation on Texas reservoir lakes. Ecological Monographs
10:111-143.

Hillis, D. M. and J. D. Patton 1982. Morphological and elec-
trophoretic evidence for two species of Corbicula (Bival-
via; Corbiculidae) in North America. American Midland
Naturalist 108:74-80.

Isely, F. B. 1924. The freshwater mussel fauna of eastern
Oklahoma. Proceedings of the Oklahoma ,\cademy of Sci-
ence 4:4.3-118.

Klippel, W, E. and P E. Parmalee. 1979. The naiad fauna
of Lake Springfield. Illinois: an assessment after two de-
cades. The Nautilus 94:189-197.

THE NAUTILUS, Vol. 104. No. 1

MauldinV L 1972. The bivalvemollusca of selected Tarrant
Countv Texas reservo.rs. Masters thesis, Texas (Ju.st.an

University, Ft. Worth. 83 p. , , , l l Rl Texas

u n 1^72 Fresh water mussels of Lake LBJ, iexas.

"" BnlSi^of t!:.f A^ican Malacolog.cal Union 1972:36-

Murrt H D 1978. Freshwater mussels of Lake Corpus
Christi, Texas. Bulletin of the .\mencan Malacolog.cal

Muriv'n a^982: Un.onuls trom Ind.an sUes in McMullen
and Live Oak counties, Texas. Bulletn, of the .American
Malacological Union 1981:10-11
Murray H D and A. B. Leonard. 1962. Handbook of umomd
"""muils in Kansas. University of Kansas Museum of Nat-
ural Historv Miscellaneous Publication 28 184 P
Neck R W 1982a. Preliminary analysis o the ecological
zoogeographv of the freshwater mussels of Texas. In: Da-
vis ] R. (cd.y Proceedings of the symposium on recent
benthological investigations in Texas and adjacent states.
Texas Academy of Science, Austin, p. .■>3-42.
Neck, R. W. 1982b. A review of interactions between humans
and freshwater mussels in Texas. In: Davis, J, R. (ed.)^
Proceedings of the symposium on recent benthological
Lestigations in Texas and adjacent states. 1 exas Academy
of Science, .Xustiii, p. 169-182. , , , t, ,i,„„i

Neck R W. 1986. Freshwater bivalves of Lake Tawakom,
Sabine River, Texas. Texas Journal of Science 38 241-249.
Neck R W 1987. Freshwater bivalves of the Baffin Bay
drainage basin, southern Texas. Texas Journal of Science

Neck^^R'w ^1989a. Freshwater bivalves of Medina Lake,
Texas: factors producing a low-diversity launa. Texas Jour-
nal of Science 41.319-325. ,. , , , u 1
Neck R W 1989b. Freshwater bivalves ol Lake Arrowhead
' Texas: apparent lack of local extirpation. Texas Journal of

Science 41:371-377. . i • i ^c

Neck R W and A. L. Metcalf. 1988. Freshwaer bivalves
■ of the lower Rio Grande, Texas. Texas Journal of Science

40:259-268. , , , ,

Neel 1 K 1941 A taxonomic stud> ot (Juadrula qnadruta

'(Rafinesque). Occasional Papers of the Museum Zoologv

of the University of Michigan 448:1-8.
Nelson, D. J., T. C. Rains, and J. A. Norris. 1966. High-purity

calcium carbonate in freshwater clam shell Science 152:

1368-1370. , . , . ,

Parmalee, P. W- 1955 Some ecologica aspects ol l^^ "^lad
fauna of Lake SpringGeld, Illinois. The Nautilus 69.28-34.
Peach J L 1983 Comments on the commercial shell in-
dustry, past and present In: Miller, A. L^i';™"Pi'''^'- Re-
port of freshwater mussels workshop; 26-2, October 1982.
U.S. .'\rmy Engineer Experiment Station, \ icksburg. MS,

p. 84-89.' „ „

Read, L. B. 1954. The I'elecypoda ol Dallas County, I exas

Field & Laboratory 22:35-52.
Read L. B. and K. H. Oliver. 1953. Notes on the ecology ot
the freshwater mussels of Dallas County. Field & Labo-
ratory 21:75-80
Roback, S. S., D, J. Bereza, and M F. Vidrine 1980. De-
scription of Ablashesmyia (Diptera:Chironomidae:lany-
podinael svmbiont on unionid freshwater mussels (Mol-
lusc a BivaKia:Unionacea), with notes on its biology and
zoogeography. Transactions of the American Entomolog-
ical Society 105:577-619.
Smipson. C. T 1914. A descriptive catalogue ot the naiades
or pearly freshwater mussels. Detroit, 1540 p.

SmsileN J .V 1893. A prclmunary l.st of the land. Ireshwater
and marine Mollusca of Texas, Annual Report Geological
Survey of Texas, 1892. 4:299-343.
S.nilh 1 \ 1973. Primary productivity and nutrient rela-
■ tionships inGarza-LittleElm Reservoir. Ph D. dissertation.

North Texas University, Denton, 118 p.
Stansberv D H. 1971. A study of the growth rate and lon-
gevity of the naiad Amblema plicata (Say, 1817) in Lake
Erie (Bivalvia: Unionidae). Annual Report ot the American
Malacological Union. 1970:78-79. , ^ ■ i ,„J

Stansberv, D. H. 1983. Some sources of nomenclaorial and
systematic problems in unionid mollusks. In: \ il er, A. L..
(compiler). Report of freshwater mussels workshop; 2b-
27 October 1982, U.S. Army Engin. Waterways Exp, Sta..
Vicksburg, MS, p. 46-62.
Strerker 1 K 1931. The distribution of the naiads or pearls
freshwater mussels of Texas. Baylor University Museum
Special Bulletin 2, 71 p ... r ,

Trdan R J and W, R. Hoeh. 1982, Eur> topic host use lor
two congeneric species ot freshwater '"^"f l* ?'''«■> P^^^^
Unionidae: Anodonto). American Midland Naturalist 108:

Turgeon't^D., A. E. Bogan, E. V. Coan, W. K. Emerson, W.
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g', Thompson, and J. D. Williams. 198a Common and
scientihc names of aquatic invertebrates from the Umted
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Special Publication 16:1-277,
ValenUne, B. D. and D. H. Stansber> , 1971. An mtroduc ion
to the naiads of the Lake Texoma region, Oklahoma, w ith
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kiana 42:1-40. ,

White, D. S. and S, J. White, 197,, Observa ions on the
pelecvpod fauna of Lake Texoma, Texas and Oklahoma,
after more than .30 years impoundment. Southwestern
Naturalist 22:235-254.
Winton, W. M. 1925. The geology ol Denton County, Uni-
versity of Texas Bulletin 2544, 86 p.

APPENDIX

Below is a list of collecting localities on Lake Lewisyille,
Denton County, Texas, that were used for this study.
Numbers are keyed to those in figure 3.

1. Northeast end of -old'- Garza Da.B, west or "old-
Lake Dallas side. , ,., , cu .

2. Graveyard Slough, 17.5 km south of Shady Shores

community. r .

S. Willow Grove Park, 1.25 km east ot center ot city

of Lake Dallas. r ■ ■ -ll^

4. East Hill Park, ID km north ot spillway ot LewisvUle

Dam. , , .,, ,f

5. Stewart Creek Park, 15 km north ot spillway of

Lewisville Dam. ,

(,. Ilackberrv Park, east side of large cove m south-
eastern portion of Lake Lewisville State Park, 3.6

km west of FM 423. ., , , n i /PMl

7 Little Elm bridge on Farm-to-Market Road (FM)
720, .southeast portion 1.5 km southwest ot com-
munity of Little Elm.
8. Cottonwood Park, l.S km south-southeast of Little
Elm bridge (FM 720).

R. W. Neck, 1990

Page 25

9. Northeast end of "old" Garza Dam, east or "new"
Lake Lewisville Side.

10. Oakland Park, 0.7 km northeast of Copperas Point
(across Hickory Creek Arm).

1 1 . Fish-O-Rama (private commercial development ), just

southeast of boundary of Hickory Creek Park, 0.85
km west of IH 35 E.
12. Sycamore Bend Park, 2.9 km west of Interstate High-
way 35E.

THE NAUTILUS 104(1 ):26-28, 1990

Page 26

A Reaffirmation of the Nomenclatural Status of
Octopus filosus Howell, 1868, the Senior
Synonym of Octopus hummelincki Adam, 1936

Ronald B. Toll

Depaitmcrit i)l Biology
The L niversil\ of llie South
Sc«aneo. T\ 37375 USA

ABSTRACT

Voss (1962) placed Octopus Ituinnicliucki Adam, 1936 into the
synonyiiu of Octopus filu.sus Howell, 1868; however, the ma-
jority of accounts dealing with this ta.xon since that time have
continued to use the junior synonym. The type material of both
taxa were reexamined and their nomenclatural histories traced.
O. filosus is upheld as the correct senior s\ nonvm and a com-
plete s) nonynn is provided

Key words: Octopus filosus. Octopus huiniiuliucki. Octopo-

Hovvell (1868) described Octopus filosa from Santa Cruz
Island (= St. Ooi.x in the Virgin Islands). The original
description, based on the largest of several live animals
Howell had seen, is brief but contains details of body
morphometry, arm lengths and the lunnber of adoral,
uniseriall) arranged suckers along each arm. Howell
(1868:241) commented that the animal was "remarkable
for the long and thread-like terminations to the arms
. . .". As part of his description of the coloration of the
live animal he also noted (p. 241) that "it changes the
color of its spots with great rapidity." Howell illustrated
the holotype in ventral whole view. In his monographic
work on the Octopodinae, Robson (1929) included Oc-
topus (Octopus) filosus based .solely on Ilowell's original
description and corrected the gender of the specific ep-
ithet.

Adam (1936) described Octopus hummelincki from
Bonaire, Netherlands West Indies baseil on three syn-
types (1 male, 2 females). He noted the presence of a
pair of ocelli located between the eyes and the edge of
the web. The following year, based on the syntypic series,
•Adam (1937) expanded his description and provided
photographic whole views of two of the types and iihi.s-
traliori:i of the hectocotylus, penis, and fuiuiel organ.

Bused .■!! Howell's description alone, Pickford (1945)
plated Octopus filosus into the synonymy of O. vulgaris
bccau.se o( i,i r (jf-rception of a lack of a clear morpho-
logical distinition between several Floridian specimens

of O. vulgaris with attenuate arm tips that approached
the condition for filosus as described by Howell.

Voss (1962), in a report on the cephalopods in the
collections of The Academy of Natural Sciences of Phila-
delphia, reexamined the holotype ot Octopus filosus and
noted (p. 2) the presence of a "faded but distinct ocellus
beneath each eye and scattered thin, thread-like papillae
on the dorsimi of the head and mantle . Based on this
combination oi characters, particularly the ocelli (to which
Howell s comment regarding the changing colors of the
"spots" probably refers), Voss established O. filosus as
the senior synonym of O. hummelincki. Voss further
noted that due to the use of the name filosus by both
Robson (1929) and Pickford (1945) [an additional ref-
erence to this taxon by Pickford (1946) apparently was
overlooked], its use could not be suppressed by plenary
power [e.g., invocation of the 50 year ride as defined by
The International Ciode of Zoological Nomenclature
(ICZN, 1985: Art. 79)].

Probably because \'oss' 1962 paper is relatively ob-
scure and the nomenclatural situation regarding Octcjpus
filosus was mentioned only briefly (one paragraph), .Ad-
am s hummelincki has been maintained and used rou-
tinely as the specific epithet for this taxon in subsequent
accounts. In turn, Howells filosus has been relegated to
remain among the nimierous taxa recognized as junior
synonyms of O. vulgaris and as such is \ irtualK unknown
to a new generation of cephalopod workers.

In order to verify the systematic and nomenclatural
disposition of Octopus filosus and O. hummelitu^ki. I
reexamined the types of both taxa. The holoty pe of O.
filosus (Acadetny of Natural Sciences of Philadelphia
A6450) is a female (ML 36 mm) with maturing eggs,
now in fair condition. Indications of both ocelli are extant
and the manllc. ticad, antl basal portions ot the arms are
covered w itli thin papillae. Two oi the three sy ntypes of
O. hummelincki were obtained from the Zoologisch Mu-
seum-Universiteit Van Amsterdam (1 male with sper-
matophores, 1 female, ML 21 and 18 mm, respectively).
Both specimens are in excellent condition, the ocelli are
distinct, and the mantle, head and arms are ornamented

R. B. Toll, 1990

Page 27

with tall, thin papillae. The oiiK other octopod with
similar ocelli fouiKl in the Atlantic Ocean is O. maya
V'oss and Solis, 1966, which is entlemic to the Gulf of
Campeche, Mexico. In addition it attains large size (to
2.0 kg). My reexamination of the types and the known
distribution of ocellated octopods from the Atlantic Ocean
support \'oss" contention that O. filo.siis and O. hiim-
melincki are s\ non\ ms.

The name hummclincki has appeared in 26 accounts
including the original description. Of these, five are species
catalogues, three others include Octopus hummeliuchi
in a dichotomous key onl\-, and two more cite other
papers without the addition of new data. The remaining
16 papers (which include 2 unpublished theses) include
new information of a systematic, nomenclatural or bio-
logical nature. The name filosus has appeared in four
svstematic-tvpe treatments within the last fifty years
(Pickford, 1945, 1946; Voss, 1962; Toll, 1988). Addition-
ally it is listed, without comment, in the synonymy of
O. hiimmeliticki b\ Burgess (1966) and Roper et al.
(1984); however, these accounts do not constitute usage
as defined in Article 79c(l)i of the ICZN (1985). As
previously noted by V'oss (1962), Howell s name cannot
be suppressed by the use of plenary power (see ICZN,
1985:Art. 79c). .\s a result, O. filo.siis is here reaffirmed
as the senior synonym of O. hummclincki and should be
used as such. To be the best of m> know ledge, the com-
plete synonynn of O. filosus is as follows:

Octopus filosus Howell, 1868

Octopus filosa Howell, 1868:240.

Octopus filosus, Robson, 1929:146.— Pickford. 194.5:709; 1946:
422.— Voss, 1962:2.— Burgess, 1966:770.— Roper et al.
1984:201.— Toll, 1988:209.

Octopus {Octopus) rugosus (= Octopus vulgaris Lamarck.
1798), Robson, 1929 {pars, only specimen B,M.190;3.9.17,9.,
fide Pickford. 1946424).

Octopus hummclincki Adam, 19:36:1; 1937:2.5, Pickford. 1945:
745; 1946:414; 1950:1:39.— Voss, 1949:3; 1953:7.'3; 1956:
279; 1962:2; 1968:657; 1975:351; 1976:77 —Rees, 1950:
107.— Burgess, 1966:762.— Voss and Solis, 1966:624 —Pa-
lacio, 1977:101.— Cairns, 1976:2.58 —Wodinsky, 1977:
947— Nesis, 1982:302,— Aroclia-Pietri, 1983:37,— Roper
et al, 1984:201 —Calow, 1987:360,— Mangold, 1987:
182.— Hanlon. 1988:252 —Toll, i988:209 — \'ecchione et
al, 1989:20,

Octopus vulgaris. Pickford. 1945708 [pars, non O. vulgaris
Lamarck, 1798).

ACKNOWLEDGMENTS

George Davis and Mary Garback, Academy of Natural
Sciences of Philadelphia, loaned the holotype of Octopus
filosus. Robert Moolenbeck, Zoologisch Museum-lini-
versiteit Van Amsterdam, loaned the syntypes of O. Inim-
melincki. Michael Sweene\, Division of Mollusks, Na-
tional Museum of Natural History, conducted a computer
literature search that aided in the construction of the
synonymy. Susan Armentrout, Dupont Library, The Llni-
versity of the South, assisted in the acquisition of liter-

ature records. Their contributions are gratefully ac-
knowledged. This contribution was supported by a grant
from the National Science Foundation (BSR 8508439)
and general support for research from the University of
the South.

LITERATURE CITED

.Arocha-Pietra F 1983, Cephalopodos del genero Octopus
en el area insular del oriente de X'enezuela Master's Thesis,
L iiiversidad de Oriente. (Aunana, Wnezuela. 135 p.

.\dam, W. 1936. Notes sur les cephalopods. \4. — Une nou-
velle espece d'Octopus (Octopus humnteliucki sp. nov.)
des les hides occidentales Neerlandaises, Bulletin du Musee
ro\al d Histoire naturelle de Belgique 12(40): 1-3,

■\dam, W 1937 Ceplialopodes des lies Bonaire et Curacao.
Capita Zoologica 8:1-29

Burgess, L. A, 1966, \ stud\ of the morphology and biniogv
of Octopus hummclincki .\dam, 19:36 (Mollusca: Cepha-
lopoda). Bulletin of Marine Science 16(4):762-813-

Cairns, S. D 1976. Clephalopods collected in the Straits of
Florida bv the R/V Gerila. 15ulletin of Marine Science
26(2):233-272.

tialow , P, 1987, Fact and theory — an overview. In: Bovle, P,
R, (ed, ), Cephalopod life c\cles, volume IP comparative
reviews. Academic Press, London, p, ■351-;365.

llanlun. l\ T 1988. Behavioral and body patterning char-
acters useful in ta,\ononi\ anil field itlentificati(}n of cepli-
ak)pods, Malacologia 29( f ):247-264.

Howell, S, B, 1868, Descriptions of two new species of ceph-
alopods. American Journal of Conchologv 3:239-24 i,

ICZN, 1985. International Code of Zoological Nomenclature,
3rd ed. University of California Press, 338 p.

Mangold, K. 1987. Reproduction. /n: Boyle, P. R. (ed.). Ceph-
alopod life cycles, volume II: comparative reviews .-Vca-
demic Press, London, p. 157-200,

Nesis, K, .N, 1982, Brief svnopsis of certain cephalopod mol-
lusks of the world's oceans (in Russian), L',S,S,R,, 358 p,

Palacio. F, J, 1977, .\ stud\ of the coastal cephalopods from
Brazil with a review of Brazilian zoogeography. Doctoral
Dissertation, University of Miami, Florida. 311 p

Pickford, G. E. 1945. Le poulpe Americain: a study of the
littoral Octopoda of the western Atlantic. Transactions of
the Connecticut .Acadenu of .\rts and Sciences 36:701-
811,

Pickford, G, E, 1946. .\ review of the littoral Octopoda from
the Central and Western Atlantic stations in the collections
of the British Museum. .-Vnnals and Magazine of Natural
History, Ser. 11, Vol, 13:412-429,

Pickford, G. E. 1950 Tlie Octopoda of the Oxford L'niversity
Cayman Expedition. Proceedings of the Malacological So-
cieU of London 28(4,5):139-144.

Rees, W J 19.50. Notes on the cephalopods from the Carib-
bean. Proceedings of the Malacological Society of London
28(2,3):107-114,

Robson, G, C, 1929, ,A Monograph of the Octopoda, The
Octopodinae, British Museum (.Natural Hislorv), London,
236 p.

Roper, C, F, E., M, J, Sweeney, and C E, Nauen, 1984.
Cephalopods of the world. Food and .Agriculture Orga-
nization (F.\0) Species Catalogue Vol. 3,277 p. FAO Rome.

Toll, R, B. 1988. The use of arm sucker number in octopodid
systematics (Cephalopoda: Octopoda). .American Mala-
cological Bulletin 6(2):207-21I.

\ ecchione, M., C. F E Roper, and M J Sweeney. 1989

Page 28

THE NAUTILUS, Vol. 104, No. 1

Marine flora and fauna of the eastern United States. Mol-
lusca: Ck'phalopoda. .\OA.-\ Teclinieal Report NMFS 73,
22 p.

Voss, G. L. 19-19. Notes on a specimen of Oclopu.s humnic-
lincki .Vdani from the Florida Keys. Revista de la Soeiedad
Malacologica Carlos de la Torre 7{l):3-5.

\'oss, G. L. 1953. Observations on a living specimen of Oc-
topus hummelincki Adam. Nautilus 66:73-76.

\'oss, G. L. 1956. A checklist of the cephalopods of Florida.
Quarterly Journal of the Florida .Xcademy of Science 19:
27-1-2S2.'

Voss, G. L. 1962. List of the types and species of cephalopods
in the collections of the Academy of Natural Sciences of
Philadelphia. Notulae Naturae No. 356, 7 p.

X'oss, G. L. 1968. Oclopods from the R/V Pillsbury south-

western C^aribbean cruise, 1966, with a description of a
new species. Octopus zonatus. Bulletin of Marine Science
18:6-4.5-659.

Voss, G. L. 1975. Etuixoctupm, pillslmnjac. nt-w species, (^1'0\-
lusca; Ck'phalopoda) from the southern (Caribbean and Sur-
inam. Bulletin ol Marine Science 25(,3);346-.352.

\'oss, G. L. 1976. Seashore life of Florida and the Caribbean.
Seemann Publishing, Inc., Miami, 168 p.

\oss, G. L. and M. Solis. 1966. Octopus maya, a new species
from the Bay of Campeche, Mexico. Bulletin of Marine
Science 16(3);615-625.

W'odinsk), J. 1977. Hormonal inhibition ot feeding and death
in Octopus: control by optic gland secretion. Science 198:
948-951.

THE NAUTILUS 104(1 ):29-32, 1990

Page 29

Coelatura Conrad, 1853, Caelatiira Conrad, 1865 and
Coelatura Pfeiffer, 1877 (Mollusca):
A Tale of Two Diphthongs

Gary Rosenberg
Arthur E. Bogan
Earle E. Spanier

Acaderii) of Natural Sciences
19th and the Parkway
Philadelphia, PA 19103, L'SA

ABSTRACT

Coelatura Conrad, 1853 is the valid name for the genus of
unionid bivalves emended to Caclatura by Simpson (1900).
The family-group name Caelaturinae Model!, 1942 must be
corrected to Coelaturinae Modell. Caclatura Conrad, 1865 is
the valid name for the genus of barleeid gastropods renamed
Actaeonema Conrad, 1865. Coelatura Pfeiffer, 1877, Coela-
tura von Martens, 1880, Caelatura Germain, 1921 and Ario-
caelatura Germain, 1921 are objective synonyms of Plegma
Gude, 191 1, a genus of heli.xarionid gastropods. Confusion among
these names has resulted from the difficulty in distinguishing
between the "ae and "oe diphthongs when they are printed
as ligatures. The ligature for "ae" in some typefaces is used as
an "oe' in others. The only way to be sure of an author's
intentions is to compare words of known spelling.

Key words: Barleeidae, Actaeonema. Caclatura: diphthongs;
Helixarionidae, Plegma: L'nionidae. Coelatura.

INTRODUCTION

During routine curation of the moUusk collection at the
Academy of Natural Sciences of Philadelphia, we came
across a nomenclatural problem in trying to put speci-
mens identified as Caelatura in their proper position in
the systematic collection. The name Caclatura was in
use in both the Bivalvia and the Gastropoda, and sub-
sequent research in the literature revealed further prob-
lems with misspellings and emendations affecting taxa
in three families. Most of these complications stem from
the difficulty of distinguishing the "ae ' and "oe " diph-
thongs when they are printed as ligatures, as they were
in the texts in which the names considered here were
introduced. We have found that the ligature for "ae ' in
some typefaces is used as an "oe " in others and that the
only way to be sure of an author's intentions is to compare
words of known spelling. To sort out the confusion caused
by these diphthongs and their ligatures, we rely on the
provisions of the Internatiotial Code of Zoological No-
menclature (ICZN, 1985). We note at the outset that ae

and DC are regarded as interchangeable for the purposes
of homonymy in species-group names (ICZN Article 58),
but not in genus-group names, in which a single letter
difterence is sufficient to avoid homonymy (Article 56b).
We also make use of the ICZN's provisions for deter-
mining if subsequent spellings are misspellings or emen-
dations, and for determining if emendations are justified
or unjustified.

TAXONOMY

Coelatura Conrad (Bivalvia: Unionidae)

In 1853, Conrad named the genus Coelatura, with the
single included species Unio aegyptiacus Cailliaud,
1827. He used the spelling Coelatura twice (p. 267, 268),
and the distinction between the "oe" and "ae" ligatures
is clear in the text. Simpson (1900) used Conrad's genus
for a group of African unionid bivalves, but spelled it
"Caelatura," (p. 820, S62 and in the index, p. 1004). The
instance on page 862 looks like it is spelled with an "oe,"
because there is little difference between the ae and oe
ligatures in the italic typeface in Simpson's work. In-
spection of words such as "aegyptiacus" (p. 821), "lae-
vigatas" (p. 600) and "coctcstis" (p. 905) shows that he
used the spelling "Caclatura" throughout. This consis-
tent use qualifies as an intentional emendation (ICZN
Article 33b(i)). As there is no evidence in Conrad's text
that Coelatura is an original misspelling, the emendation
is unjustified and introduces the name Caelatura Simp-
son, 1900, which is a junior objective synonym of Coe-
latura Conrad, 1853 (Article 33b(iii)), and is also a junior
homony m of Caclatura Conrad, 1865 (Gastropoda). Most
authors after Simpson incorrectly used the name Cae-
latura, rather than Coelatura, exceptions being Yokes
(1980:96) and Vaught (1989:124). Modell (1942:190) in-
troduced the subfamilial name Caelaturinae based on
the emended spelling of Coelatura and Starobogatov
(1970:64) used the tribal name Caelaturini. These must

Page 30

THE NAUTILUS, Vol. 104, No 1

be corrected to Coeiaturinae Model), 1942 and Coela-
turini Modell, 1942 (Article 35d(ii)).

There is also a question as to the correct spelling of
the name of the type species of Coelatiira (Conrad. Cail-
liaud (1823-1827) rendered it Vnio aegyptiacu.s in the
text (p. 263), but Vnio egyptiacus in the plate caption
(pi. 61, fig. 5-6). Most authors have used the spelling
found in the text, which was published in 1827, but the
plate might have been published before then as the atlas
v\as issued in parts between 1823 and 1827 (Sherborn &
Woodward, 1901:334). From the available evidence, we
cannot prove that the plates were issued before the text,
so we retain the spelling "aegyptiacus."

Caelatura Conr.ad (Gastropoda: Barleeidae)

In 1865, Conrad published a catalogue of Eocene and
Oligocene shells of the United States, in which he intro-
duced the name Caelatura (Conrad, 1865a). He included
the species Pasithea sulcata Lea, 1833 and P. striata
Lea, 1833 in Caelatura. w hich he placed in the Terebri-
dae on page 28. However, he also listed Caelatura in the
.Acteonidae on page 35, including only Pasithea striata.
Tr\on (1865), the editor of Conrad's paper, stated that
Caelatura striata and sulcata both should have appeared
on page 35, not on page 28. Later in the year, Conrad
renamed Caelatura as Actaeonerna (1865b: 147), citing
page 35 and not page 28 of his earlier work, and illus-
trating Actaeonerna striata (pi. 11, fig. 2). He did not
state why he replaced the name. One might assume that
he replaced Caelatura because of its similarity to the
prior Coelatura. Iiut Ponder (1983) argued that Conrad
meant to restrict the name Caelatura to Pasithea sulcata
on page 28 and to provide a new genus for Pasithea
striata on page 35. This interpretation is demonstrably
incorrect because of Tryon's editorial correction and be-
cause Cionrad later (1866:9) included both sulcata and
striata in Actaeonerna and no longer used Caelatura.
Thus, both Pasithea sulcata and P. striata Lea, 1833 are
originally included species in Caelatura. and Aetaeone-
rtia must be regarded as a replacement name for it and
therefore an objective synonym.

There is also confusion regarding the type species for
Caelatura Conrad, 1865. We note that because Caela-
tura and Actaeonerna are objective synonyms, the first
valid type designation for either is a type designation
for both (Article 67h). Some authors (Tryon, 1887:53;
Fischer, 1885:779) have given Pasithea striata as an ex-
ample of Actaeonerna, which does not qualify as a type
designation. It should be noted that Palmer (1937:154)
demonstrated that Conrad (1865b) misidentified Pasi-
thea striata Lea; the species he figured (pi. 11, fig. 2) is
Tuba cancellata Lea, a mathildid. Palmer (1937:68) sug-
Ki'sled that P. striata Lea is ba.sed on a turritellid pro-
tucoiuh Inspection of the type lot (ANSP 5502) confirms
ih:ii tin- /'. striata is not a barleeid or a mathildid, but
its aftinitie."; with turritellids are uncertain, as indicated
h\ !'' ,1 II if r i ] 985: 1 05). Because Conrad (1865a) cited only
Lea ! tvi- Iv^MiTs of P. striata and P. sulcata, his later

(1865b) misidentification of Pasithea striata has no bear-
ing on the type species question, a point not realized b\
later authors. Palmer (1937:156) and Moore (1962:98)
treated Actaeonerna striata as a species described by
Conrad, but this is incorrect, as Conrad was merely in-
troducing a new combination. Cossmann (1893:29) stated
of Actaeonerna striata (Lea):

II y a lieu de remarquer que ce nest pas cette espece qui
est le veritable t\ pe du genre .Actaeonerna. mais Pyramis
striata. C>)nrad, c est a dire Pasithea .sulcata ou I espece
precedeiite [.Actaeonerna sulcatum (Lea)], de sorte que
Toil pent desormais fi.xer, d uue niariiere beaucoup plus
certaine, les caracteres de ce genre.

Cossmann thus equated Conrad's misidentification of
Pasithea striata with P. sulcata Lea (Conrad had syn-
onymized them as Pyramis striata in 1834), but this is
incorrect as shown by Palmer (1937). Because Coss-
mann s statement is ambiguous, it does not qualify as a
type designation (ICZN Article 67c(3)). Cossmann later
(1921:49) explicitly cited Pasithea sulcata Lea as the type
species of Actaeonerna: this is the first valid t\pe des-
ignation that we have found. Ponder (1983:244) recog-
nized P. sulcata as the type species of Caelatura, which
he placed in the Barleeidae, but incorrectly considered
P. striata to be the type of Actaeonerna.

CoEL.\TVRA PfEIFFER (GASTROPODA:

Hellxarionidae)

Pfeiffer (1877:8) also named a Coelatura. type species,
by monotypy, "//. coelatura Fer."[= Helix (Helicogena)
coelatura Ferussac, 1821], a Mascarene land snail. Von
Martens (1880:192) used Coelatura as a subgenus of
Pachxjstyla without attributing authorship to the name,
but he included "Pachystyla caelatura Ferussac (Helix
Helicogena), among other species, so it appears at first
that he was referring to Pfeiffer s genus. However, von
Martens (1881:74) cited himself as having introduced
Coelatura in ISSO. Therefore, we select Pachystyla cae-
latura (Ferussac) [= Helix (Helicogena ) coelatura Ferus-
sac, 1821], by reason of virtual tautonomy. as t\'pe species
of Coelatura von Martens, 1880, making it an objective
synonym of Coelatura Pfeiffer, 1877. Coelatura Pfeiffer
non Conrad was replaced b\ Plegnia Gude, 1911 and is
now placed in the Helixarionidae. (Helicarionidae is a
misspelling based on the unjustified emendation of He-
lixarion Ferussac, 1821 to Helicarion b\ Ferussac (1822)
(Kennard, 1942).)

Some authors (e.g.. Zilch, 1959:308) consider Pfeiffer's
Coelatura to have been emended to "Caelatura" by
Fi.scher. However, Fischer spelled Coelatura correctly
in the text (1883:461); it is misspelled in the index (1887:
1339), as noted by Schuize et al. (1927:482), but this
cannot be construed as an emendation, and has no no-
menclatural standing. The first author to have emended
Pfeiffer's Coelatura to Caelatura appears to be Germain
(1921:103), apparently because he thought that the cor-

G. Rosenberg et al., 1990

Page 31

rect spelling of the type species was Helix caelatura, not
Helix coelatura as given by Pfeiffer (1877:192). How-
ever, this is an unjustified emendation because Pfeiffer's
Coelatura cannot be considered an incorrect original
spelling based on evidence in Pfeiffer's text (ICZN Article
32c(ii)). Further complicating matters, Germain (1921:
461), who was unaware of Gude's Plegrna, introduced
Ariocaelatitra as a replacement for Pfeiffer's name when
he realized that it was preoccupied. Thiele (1931:615)
and Viader (1937:79) considered Ariocaelatura and
Plegma to be distinct genera although they are objective
synonyms. Wenz (1947) introduced the name Psciido-
caelatura for Ariocaelatura "Thiele" non Germain, with
type species Pachystyla scalpta (von Martens, 1877).
Wenz s name is preoccupied by Pseudocaclatura Ger-
main, 1921 and was replaced by Dancea Zilch, 1960.

There has been confusion as to the correct spelling of
the specific name of Helix (Helicogena) coelatura be-
cause of inconsistencies in Ferussac's work (1819-1832).
The species was illustrated on plate 28 (fig. 3, 4), the
caption of which was published on 6 April 1821. A second
reference to the plate appeared later that year in Ferus-
sac 1821a (p. 30 of the quarto edition, p. 34 of the folio),
which was published 26 Ma\ 1821 (dates from Kennard,
1942:109, 1943:122). In the plate caption, the specific
name is spelled "coelatura," but from inspection of other
words in the captions in the same italic t\ peface, it is
apparent that the typesetter often substituted ligatures,
using oe for ae. For example, acavae (pi. 33, 35), acavoe
(pi. 25, 30, 32, 34, 36); columellatae (pi. 11, 15, 17),
colurriellatoe (pi. 15, 17, 25, 32); and perforatoe for per-
foratae throughout. The vernacular descriptor that Fer-
ussac gave this species in the caption is "ciselee." mean-
ing carved or sculpted, corresponding in meaning to the
Latin caelatura. However, coel- is sometimes used as an
alternate spelling for the Latin root cael-, so it cannot
be proven from the evidence of the original publication
that "coelatura" is a misspelling. In 1821a (p. 30) and
1827 (p. 302) Ferussac used the spelling "caelatura." but
these do not qualify as emendations as the spelling ap-
pears only once in each work. The spelling "caelatura"
is repeated four times by Deshayes in Ferussac and De-
shayes (1850:162), which qualifies as an emendation.
(Deshayes continued Ferussac's work after the latter s
death in 1836). In the complete set of plate captions for
the work (Ferussac and Deshayes (1851 in 1819-1851))
the spelling "coelatura" recurs, presumabK' copied from
the original plate captions. Both spellings have been used
with about equal frequency in the literature, as shown
in the synonymy by Germain (1921:103). The two most
recent references to the species that we have found (Zilch,
1959:308; Groh and Griffiths, 1987:39) use the spelling
"coelatura." Because "coelatura" has priority, cannot be
proven to be an original misspelling, and does not threat-
en nomenclatural stability. Helix (Helicogena) coelatura
Ferussac, 1821 is the correct citation for the t\pe species
of Plegma. Helix caelatura Deshayes in Ferussac and
Deshayes, 1850 is an unjustified emendation and an ob-
jective synonym of it.

Summary

We have established the status of the following names;
valid names are listed first followed by objective syn-
onyms:

Coelatura Conrad. 1853 (Bivalvia: Uiiionidae) [type species,
by moiiotypy, Unio aegyptiacus C^ailliaud, 1827]
+ Caelatura Simpson, 1900
Caelatura Conrad, 186.5a (Ga.stropoda: Barleeidae)[t>pe species,
b\ subsequent designation of Cossmann (1921:49), Pasi-
thca sulcata Lea, 1833]

+ Actaconcma Conrad. 1865b
/'/r^'/iuj Glide, 1911 (Gastropoda; Helixarionidae) [type species,
b\ monot>py, "H. coelatura Fer. " = Helix (Helicogena)
coelatura Ferussac, 1821]
-I- Coelatura Pfeiffer, 1877
+ Coelatura von Martens, 1880
-I- Caelatura Germain, 1921
-I- Ariocaelatura Germain, 1921

ACKNOWLEDGEMENTS

We thank Audi Garback for bringing this problem to
our attention. Kenneth C. Emberton and two anonymous
reviewers provided helpful comments, Robert Robertson
aided with translations, and Kenneth J. Boss and P. K.
Tubbs advised on interpretation of the ICZN. This work
was made possible b\ NSF Grant BSR-8911074 for col-
lection support in the ANSP malacology department.

LITERATURE CITED

Cailliaud, F 1823-1827. Voyage a Meroeet au Fleine Blanc,
vol. 4, 415 pp., 1 pi , atlas vol. 2, 75 pi

Conrad, T. A. 1834. Fossil shells of the Lower Tertiar\ or
Eocene period. In: Morton, S. G. Synopsis of the organic
remains of the Cretaceous Group of the United States Key
& Biddle, Philadelphia, p. 3-8, appendix

Conrad, T, .\. 1853. A synopsis of the family of naiades of
North America, with notes, and a table of some of the
genera and sub-genera of the family, according to their
geographical distribution, and descriptions of genera and
sub-genera. Proceedings of the Academy of Natural Sci-
ences of Philadelphia 6:243-269.

Conrad, T, A. 1865a. Catalogue of the Eocene and Oligocene
Testacea of the United States, American Journal of Con-
chology 1:1-35 [published 25 February 1865].

Conrad, T. A. 1865b Descriptions of new Eocene shells of
the United States. American Journal of Conchology 1:142-
149, pf 10-11 [published 15 April 1865].

Conrad, T. A. 1866. Check list of the invertebrate fossils of
North America. Eocene and Oligocene. Smithsonian Mis-
cellaneous Collections 200, iv -(- 41 p

Cossmann. M. 1893. Notes complementaires sur la faune
Eocenique de r.\labania. Annales de Geologic et de Pa-
leontologie 12:1-51, pi. 1-2.

Cossmann, M. 1921. Essais de paleoconchologie comparee,
vol. 12. Paris, 349 p. pi, a-d, 1-6.

Ferussac, A. E. 1819-1832. Histoire naturelle generale et
particuliere des mollusques terrestres et fluviatiles. Atlas,
162 pi. [See Kennard (1942) for dates of plates and ac-
companying text.]

Page 32

THE NAUTILUS, Vol. 104, No. 1

Ferussac, A. E. 1821a. Tableau systematique de la famille
des lima9on.s, cochleae. Paris. [Quarto edition, 111 p.; folio
114 p. See Kennard (1942) for dates of publication of
signatures.)

Ferussac, .'\. E, 1827. C^atalogue des especes de mollusques
terrestres et fluviatiles, recueillies par M Rang, offic. de
la marine roy., dans un voyage aux grandes hides. Bulletin
des Sciences Naturelles et de Geologic 10:298-307, 408-
413.

Ferussac. A. E. and Desliayes, G. P. 1819-1851. Histoire
naturelle generate et particuliere des mollusques terrestres
et fluviatiles, 2 vols. [For collation see Kennard (1942).]

Fischer, P. 1880-1887. Manuel de concliyliologie et de pa-
leontologieconclnliologique. Librairie F. Savy, Paris, x.xiv
+ 1369 p . 23 pi , frontispiece.

Germain, L. 1921. Faune malacologique terrestreet fluviatile
des lies Ma.scareignes. Gaultier et Thebert, Angers, iv +
495 p., 13 pi.

Groh, K. and O. Griffiths. 1987. Africa and Adjacent Islands.
In: Parkinson, B., J. Hemmen, and K Groh. Tropical land-
shells of the world. Crista Henuiien, Weisbaden, Federal
Republic of Germany, p. 30-39.

Gude, G. K. 1911. Further note on preoccupied molluscan
generic names and a proposed new genus of the family
Helicidae. Proceedings of the Malacological Society of
London 9:361-362.

International Commission on Zoological Nomenclature. 1985.
International code of zoological nomenclature, third edi-
tion, adopted by the XX General .Assembly of the Inter-
national L'nion of Biological Sciences. London, x\ + 338 p.

Kennard, A. S. 1942. The llUtoire and Prodrome of Ferussac.
Proceedings of the Malacological Societv of London 25:
12-17, 105-118.

Kennard, A. S. 1943. Notes on the nomenclature of the Mas-
carene non-marine Mollusca. Mauritius Institute Bulletin
2:115-136.

Lea, 1, 1833 Contributions to (Jeology. Carey, Lea and Blan-
chard, Philadelphia, 227 p., 6 pi.

Modell, II. 1942. Das natiirliche System de Najaden. Archiv
fiir Molluskenkunde 74:161-191.

Moore, E. J. 1962. Conrad s Onozoic fossil marine mollusk
type specimens at the Academy of Natural Sciences of
Philadelphia, Proceedings of tfie Academy of Natural Sci-
ences of Philadelphia 114:23-120

Palmer, K. \\ W. 1937. The Claibornian Scapliopoda, Gas-
tropoda and dibranchiate (Cephalopoda of the southern
United States. Part I. Bulletins of American Paleontologv
7(32): 1-548.

Pfeiffer, L. 1877. Leber die systematische Anordiiung der
Helicaceen. Malakozoologische Blatter 24:1-14, 75-84.

Ponder, W. F. 1983. Review of the genera of the Barleeidae

(Mollusca: Gastropoda: Rissoacea). Records of the .Austra-
lian Museum 35:231-281.

Ponder, VV. F. 1985 (1984). .K re\iew of the genera of the
Kissoidae (Mollusca: Mesogastropoda: Rissoacea). Records
of the Australian Museum, Supplement 4, 221 p.

Schulze, F. E., W. Kiikenthal, and K. Heider, 1927, \omen-
clator animalium generum et subgenerum 2(6):477-636.
Preussischen Akademie der Wissenschaften, Berlin.

Sherborn, C. D. and B. B. Woodward. 1901. Dates of pub-
lication of the zoological and botanical portions of some
F'rench vovages. — Part II. .Annals and Magazine of Natural
History (7')8:333-336.

Simpson, C, T. 1900. Synopsis of the naiades, or pearK fresh-
water mussels. Proceedings of the United States National
Museum 22:501-1044, pi. 18.

Starobogatov, Y. I. 1970 Fauna mollyuskov i zoogeografi-
cheskoe raionirovanie kontinental nykh vodoemov zem-
nogo shara. Akademiya Nauk SSSR, Zoologicheskii Insti-
tut, Leningrad, 372 p,

Tliiele, J 1931, Haiidbuch der s>stematischen Weichtier-
kunde. Part 2. Gustav Fischer, Jena, p. 377-778.

Tryon, G. W. 1865. Correctionsandadditions to Mr. Conrad's
catalogue of Eocene Mollusca, published in the 1st number
of this journal. .American Journal ol Concholog) 1:191-
192. [Published 1 October 1865]

Tryon, G. W. 1887. [lanthinidae, Trichotropidae.Scalariidae.]
Manual of Conchology 9:33-111, pi. 7-18.

X'aught, K. C. 1989. .\ classification of the living Mollusca.
American Malacologists, Melbourne, Florida, xii + 195 p.

V'iader, R. 1937. Revised catalogue of the testaceous Mollusca
of Mauritius and its dependencies Mauritius Institute Bul-
letin l(2):xiv -I- 111 p., 1 map.

Yokes, H. E. 1980. Genera of the BivaKia: a systematic and
bibliographic catalogue (revised and updated). Paleonto-
logical Research Institute, Ithaca, New York, xxvii + 307 p.

von Martens, E. 1877. Ubersicht der wahrend der Reise um
die Erde in den Jahren 1874-1876 auf S. M. Schiff Gazelle
gesammelten Land- und Siisswasser-Mollusken. Monats-
bericht der Koniglichen .Akademie der Wissenschaften zu
Berlin, p. 261-291, pi. 1-2.

von Martens, E 1880 Mollusken In. Mobius, K., F. Richters,
and E. v Martens. Beitrage zur Meeresfauna der Insel
Mauritius und der Seychellen. Gutmann'schen Buchhan-
dlung, Berlin, p. 181-336, pi. 19-22.

\()n Martens, E. 1881. Mollusca. Zoological Record 17:1-104
(for 1880).

VVenz, W. 1947. Zur Taxonoinie tier Euth\ neiua, .Archi\ fiir
Molluskenkunde 76:36.

Zilch, .A. 1959-1960. Gastropoda: Eutlnneura In: Schinde-
wolf, O. H. (ed). Handbuch der Palaozoologie, vol. 6(2).
Gebriider Borntraeger, Berlin, p. i-xii, 1-834.

THE NAUTILUS 104(1):33, 1990

Page 33

Ediiardiis Pilsbry, 1930, a Subgenus of

Praticolella Martens, 1892

(Gastropoda: Stylommatophora: Polygyridae)

Kenneth C. Emberton
Leonard Richardson

Department iit Malacology
Academy of Natural Sciences
19th & the Park\va\
Philadelphia, PA 19103

ABSTRACT

The purpose of this note is to correct a iiomenclatural error
that occurs in the literature.

Pilsbry (1930:315) erected Eduardus as a section of the sub-
genus Pohjgyra {Daedalochila) Beck, 1837, with P. marten-
siana Pilsbr>', 1907, as the type and onl\ member Later, in a
brief note, Pilsbry (1937) transferred P. maricnsiana to the
genus Praticolella Martens, 1892, based on the genital anatom\
of specimens collected in 1934 at "Ingenio Agua Buena, near
Tamosopo, S.L.P., ' Mexico. Pilsbry (1956:30) continued this
assignation in a faunal paper on northern Mexico Both the
note and the faunal paper were apparently overlooked by Zilch
(1960:580, fig. 2036), who figured Praticolella (Eduardus) mar-
tensiana, but incorrectly gave the name as Daedalochila (Ed-
uardus) martensiana. This error was carried over into Rich-
ardson's (1986) catalog of species of the Polygyracea. Both
Eduardus and Einisa. which was introduced on the same page,
were omitted from Clench and Turner's (1962) "Names Intro-
duced b\ Pilsbr>. "

The shell of P. martensiana. with its depressed spire and
relatively open umbilicus, is quite distinct from those of all
other known members of Praticolella. It seems advisable there-
fore to retain Eduardus as a subgenus, pending a generic re-
vision, which is much needed although not presently planned
by either author of this note Thus. Praticolella comprises four
subgenera: Eduardus. Farragutia Vanatta, 1915; Filapex Pils-
bry, 1940; and Praticolella scnsu stricto. Pilsbr\ (1940) listed
Filapex as a section, which is equivalent to a subgenus (Inter-

national Commission on Zoological Nomenclature, 1985: Ar-
ticle He).

LITERATURE CITED

Clench, W. J. and R. D. Turner. 1962. New names introduced
by H A. Pilsbry in the Mollusca and Crustacea. Academy
of Natural Sciences of Philadelphia, Special Publication
No. 4:1-218,

International C^ommission on Zoological Nomenclature. 1985.
International Code of Zoological Nomenclature, Third
Edition. University of California Press, Berkelev and Los
.Angeles, p. 1-338,

Pilsbry, H. A. 1930. Anatomy and relationships of some .\mer-
ican Helicidae and Pol) g\ ridae. Proceedings of the .\cad-
emy of Natural Sciences of Philadelphia, 82:303-327.

Pilsbr\. H. A. 1936. Praticolella martensiana. Nautilus 49:
140

Pilsbry, H. A. 1956. Inland Mollusca of northern Mexico. III.
Polygyridae and Potadominae. Proceedings of the .Acad-
emy of Natural Sciences of Philadelphia 108:19-40.

Richardson, L. 1986 Pol\g\racea: catalog of species (parts
1, Polvgvridae; 2, Corillidae; 3, Sagdidae). Tryonia 13:1-
139, ]'-40, 1-38,

Zilch, A 1960. Gastropoda. Teil 2. Euthyneura. Band 6 In:
Schindewolf, O. H. (ed). Handbuch der Palaozoologie.
Gebrueder Borntraeger, Berlin, p 1-834

Page 34

THE NAUTILUS, Vol. 104, No. 1

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Volume 104, Number 2
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THE

CONTENTS

N AU T I L U S

Volume 104, Number 2

September 6. 1990

ISSN 0028-1344

Review of the genus Colina H. and A. Adams, 1854

(Cerithiidae: Prosobranchia) 35

Richard S. Houbrick

Harold G. Pierce

Two unusual gastropods from Late Pliocene lakes in

northeast Nebraska

Edward J. Petuch

A new molluscan faunule from the Caribbean coast of

Panama

H. Lee Fairbanks

Morphological comparisons of the species of Megapallifera
(Gastropoda: Philom>cidae)

M. G. Harasewych

Ovophagy in Anachis avara (Say, 1822) (Gastropoda:
Columbellidae)

Marine Biological Laboratory \
LIBRARY

SEP 1 7 1990

Woods Hole, Mass.

THE NAUTILUS 104(2):35-52, 1990

Review of the Genus Colina H. and A. Adams, 1854
(Cerithiidae: Prosobranchia)

Richard S. Houbrick

Department of Iinertehrate Zoology
National Museum of Natural Histor\
Smithsonian Institution
Washington. DC; 20560, USA

Page 35

ABSTRACT

The t\'pes of all nominal Colina species were examined as well
as numerous specimens in museum collections. Based on this
material and gross anatomical study of one species, a diagnosis
of the genus is presented. Fourteen species-level taxa have been
proposed; of these, three species are recognized herein: the
t\ pe-speeies. Colina macrostoma Hinds. 1844. Colina selccta
MeKill and Standen. 1S98. and Colina pinguis {A. .^dams.
18.541, The radulae of Colina macrostoma and Colina pinguis
were examined and anatomical features of the latter species
were studied for character analysis. Lectotypes for Colina cos-
tatum and Colina pinguis are selected, and Colina gracilis is
determined a nomcn dubium. The genus Colina is assigned to
the family Cerithiidae. subfamily Cerithiinae. near the genera
Biltium. Clypeomorus. and Cerithium.

INTRODUCTION

One of the more poorly known genera of the Family
Cerithiidae Ferussac, 1819, is Colina H. and A. Adams,
1854. Shells of members of this genus differ considerably
from those of all other cerithiids in having an overall
pupoid, fusiform, frequently-slender shape, and a mark-
edly constricted body whorl. The genus is not species-
rich, but the alpha taxonomy of the group has never been
comprehensively reviewed. Colina species are not well-
represented in museum collections and some appear to
be relatively uncommon in their natural habitats. To
date, their radular morphology has been obscure and
nothing has been published about their soft anatomy.

Colina has been assigned to or grouped with a com-
posite mixture of cerithiid and cerithiopsid genera, and
its placement among these groups has varied among au-
thors. For example, H. and A. Adams (1856:286) listed
Colina after Cerithium Bruguiere, 1789, and Vertagus
Schumacher, 1817. Tryon (1883:247-248) considered it
to be a subgenus of Cerithium, placing it between Cer-
ithioderma Conrad, 1860 and Cerithiella Verrill, 1882.
This allocation was obviously based on convergent shell
resemblance, as Cerithioderma is in Calyptraeoidea, while
Cerithiella is now considered a member of the Ceri-
thiopsoidea (see Marshall, 1980:85-86). Cossmann (1889:

61) believed that the protoconch of Colina was unlike
those seen in Cerithium species and suggested that it was
more like that of Lovenella Sars, 1878. a cerithiopsoide-
an. He subsequently pointed out that the name Colina
was preoccupied and considered it to be a subgenus of
Bezanconia Fischer, 1884, a fossil taxon, close to Atax-
ocerithium Tate, 1894 (Cossmann, 190690). Fossil Be-
zanconia species look very much like living species of
Ataxocerithium, a group which has been excluded from
the Cerithiidae and shown to belong to Cerithiopsoidea
(see Houbrick, 1987a). Both Thiele (1929:212) and VVenz
(1940:758-759) placed Colina within the Cerithiidae,
but grouped it with Ataxocerithium and other non-cer-
ithioidean taxa. Colina was placed after Vertagus but
before Campanile by Fischer (1884:680), thus further
linking it with non-cerithioidean taxa {Campanile is no
longer regarded as a cerithioidean. but has been raised
to superfamilial rank, Campanioloidea [see Houbrick,
1989]). Thiele (1929:212) proposed hchnocerithium as
a subgenus of Colina, but anatomical examination of the
type-species of the former taxon shows it to be a txpical
Cerithium representative (Houbrick. pers. obs. ).

As seen in the taxonomic historx presented above, the
composite systematic concept of Colina has oscillated
between cerithioidean and cerithiopsoidean assignments
due to the failure of authors to recognize convergent
shell characters in members of both superfamilies. \
comprehensive study (Houbrick, in press) of the alpha
taxonomy of Cerithium Bruguiere, sensu lato, led to
questions about Colina, as several species have been at-
tributed to both genera Examination of the types of the
nominal species of Colina and study of some preserved
anatomical material has revealed a number of interesting
characters and has prompted this review, which should
expose the genus to more comprehensive studies.

MATERIALS AND METHODS

The types of all nominal Colina species were examined
and specimens in major museums were studied to de-
termine the range of variation in shell sculpture. As few
preserved samples of Colina species were available for

Page 36

THE NAUTILUS, Vol. 104, No. 2

anatomical sIikIn. the radiila and opcrculuni ot some
species remain unkiumn. No live specimens ol Colina
were e.\amine(l Despile repeated attempts to obtain live-
collected, well-preserved specimens, the only available
material was unrelaxed, ethanol-preserved specimens of
Colina pinguis. from eastern Africa. Unfortunately, no
adult females were found during the course of this study,
and the pallia! oviducts could not be .studied.

Specimens were dissected under a Wild M-8 dissecting
microscope. Radulae and protoconchs were studied using
an Hitachi Scanning Electron Microscope.

.Abbreviations: AMS, .Australian Museum, Sydney;
ANSP, Academy of Natural Sciences, Philadelphia;
BMNM, British Museum (Natural History); BPBM, Bern-
ice P. Bishop Museum, Hawaii; DMNH, Delaware Mu-
seum of Natural History; LACM, Los Angeles County
Museum of Natural History; MCZ, Museum of Com-
parative Zoology; MNHNP, Museum National d'Histoire
Naturelle, Paris; NMW, National Museum of Wales;
USNM, United States National Museum; WAM, Western
Australian Museum.

As mentioned earlier, morphological characters de-
rived from soft part anatomy are known chiefly from
ethanol-preserved specimens of Colina pingins and from
one dried sijecirnen of C. macrosionia; thus, what follows
is incomplete and may be inaccurate, as some anatomical
features have been distorted due to poor preservation.

SYSTEMATIC REVIEW

An overview of the taxonomy, morphology, and the ecol-
og> of Colina species is presented below. A discussion of
the relationship of this genus to other cerithiids and a
review of the species follows.

Colina W and A. .Adams, 1S54

Colina H. and \ .\danis, 1854:2SH, pi oO, fig. 2 (type species
by o.d.: Cchthium macwstonia Hinds, 1844); Tryon, 1883:
247-248. pi, 69, fig. 52; 1887:141; Fischer, 1884:680; Coss-
mann, 1889:61-62; Thiele, 1929:212; Wenz, 1940:758.

Colinia H. and .A. .Adams, 1858 [emended] Cossmann, 1906:
90-91 (not C.oliuia Nuttaij, 1832, Aves); Wenz, 1940:758.

Diagnosis: Shell small, elongate, usually decollate, and
pupoid with gibbous midwhorls; teleoconch sculptured
with axial ribs; body whorl constricted. Columella with
strong internal plait. Aperture narrowly ovoid and with
expanded outer lip. Operculum corneous, ovoid, pauci-
spiral, with subterminal nucleus. Mantle edge dorsalK
fringed with papillae. Foot large, having epipodial skirt
fringed with papillae and large, posterior operculiferous
lobe; sole with well-developed propodial mucus gland
tih! massive centrally located, metapodial mucus gland
•!i longitudinal slit-like opening. Alimentar\ system
-,•; rising taenioglossate radula with scjuarish rachidian
(■" '.'i i.inf esophageal gland, and stomach with gastric
blii'-l'i jr .1 ,tyln sac. Osphradium bipectinate, very broad
CtcdiJi uin <-.\tending length ol mantle cavity and com-
prising i :ig digit .ip filaments. Pallial gonoducts open.

Epiathroid nervous system w ith long cerebro-pedal con-
nectives.

Synonymic Remarks: The name Colina was thought to
be a secondary homonym of the bird taxon, Colinus
Goldfuss, 1820; by Cossmann (1906:90-91), who emend-
ed the name to Colinia (preoccupied by Colinia Nuttall,
1832, also Aves). This action was unnecessary, as Article
56b of the International Code of Zoological Nomencla-
ture (ICZN, 1985) clearly states that even if the differ-
ence between two genus-group names is only one letter,
these two names are not homonyms; thus, Colina is a
valid genus group name, and is not preoccupied

Colina macrostoma (Hinds, 1844)
(figures 6-44)

Ccrithium macruatuma Hinds, 1844:27, pi. 26, ligs. 1 1-12 (llo-
lotype [probable]: BMNH 1989181, 10.1 mm; Type local-
it\ : Borneo); Sowerb\ , 1855:877, pi. 184, fig. 219; Sowerby
in Reeve, 1865: pi 17, fig. 118; Tryon, 1887:142, pi. 26,
figs. 10, 13-15 {in part).

Culina pupiformis A. Adams, 1853:176, pi. 20. fig. 14 iHolo-
type: BMNH 1989182, 13.6 mm. T\ pe locality: Duma-
guete, Philippines).

Ccrithium (Colina) costatum .A. Adams in Sowcrbv, 1855:126,
pi. 184, fig. 220(Lectot\pe, here selected: BMNH 1989180,
11.1 mm; Type locality: not given (not CU'rithium costa-
tum Defrance, 1817).

Ccrithium pupacjorme A, Adams. Sowerby. 18.55:877, pi. 184,
fig. 221; Sowerby in Reeve, 1866, pi. 17, fig. 122.

Ccrithium costifcrum (cmd. pro costatum .\ .Adams) Sowerb\ .
18,55:896, pi. 184, fig, 220; Sowerbv in Reeve, 1866: pi.
17, fig. 117,

Colina gracilis H. Adams, 1866:150-151 (Type material not
located, no figure given: nomen dubium).

Colina pijgmaca H. Adams, 1867:308, pi. 19, fig. 20 (Holotype:
BMNH 1878.1.28.32, 10.1 mm; Type locality: Borneo).

Ccrithium coarctatum Sowerby, 1866: pi. 12 [supplementary],
figs. 321-322 (Type material not found; Type locality: not
given; Sowerb) s fig, 32 selectetl to represent le'ctot\pe)-

Cerithium (Colina) macrostoma Hintl.s, E, .\. Smith. 1884:66-
67,

Ccritliiuni rigens Bayle, 1880:244 (replacement name for Cer-
ilhiuiu costatum .A, .Adams, 1855). Tryon, 1887:142.

Description: Shell (figures 6-41): Shell narrowly tur-
reted, elongated, comprising about 15 inflated whorls.
Protoconch small, comprising one smooth whorl. Upper
teleoconch whorls sculptured with 3 spiral cords and
numerous fine axial striae. Adult teleoconch whorls sculp-
tured with about 4 major spiral cords and 4 minor spiral
cords; central cord frecjuentK' large, carinate; subsutural
cord with minute axial pleats. Spiral cords crossed by
12-13 weak to strong axial ribs, forming cancellate sculp-
ture; intersections commonly beaded Suture moderately
impressed, distinit Boil) whorl strongly constricted,
elongated, .sculptured with broad, flattened spiral cords
and weak axial striae and incised lines. Aperture ovately
elongate with moderateK elongate, slightK reflexed ca-
nal, concave columella; lliiring outer lip of aperture, thick
and smooth at edge. Shell color [linkish tan to light brow n.

R. S. Houbrick, 1990

Page 37

cmg

Figures 1-5. Anatomical features of Colina pingttis. 1. ventral aspect of the sole of foot, showing crescent shaped propodium,
fringing papillae and operculiferous lobe of the epipodial fringing skirt, and two mucus glands, bar = 1 mm; 2. right lateral aspect
showing mantle edge and headfoot, bar = 3 mm; 3, longitudinal cross section through middle of foot showing columella muscle
and metapodial mucus gland; 4. frontal section through propodium showing details of propodial mucus gland; 5. section of
osphradium showing layout of pectens. Abbreviations: cm — columellar muscle; cmg — columellar muscle groove; d — duct of me-
tapodial mucus gland; dp — duct of propodial mucus gland; eps — epipodial skirt; f — flap covering slit into propodial mucus gland;
mmg — metapodial mucus gland; mp — mantle papilla; ms — metapodial slit; op — operculum; opl — operculiferous lobe; p — papilla;
pmg — propodial mucus gland; s — sole of foot; sn — snout.

with dark brown spiral lines and bands, and blotched
with white, especially on beads.

Radula (figures 42-44): Raduiar ribbon small, short,
about one-seventh the shell length. Rachidian tooth (Fig-
ure 44) with square basal plate having slight median
posterior projection and weak lateral fold at each pos-
terior base; cutting edge with median, spade-shaped main
cusp flanked on each side by 2-.'3 pointed denticles. Lat-
eral tooth (figure 44) with rhomboid basal plate having

short lateral extension and wide central pillar with small
pustule; cutting edge with large pointed main cusp, one
inside denticle and 2-3 outside pointed denticles. Mar-
ginal teeth (figures 42, 43) spatulate having wide bases
and curved tips w ith long pointed main cusp, 2-3 inner
pointed denticles and 2 outer denticles; outer marginal
tooth same but lacking outer denticles.

Animal: Dried specimen from Japan (ANSP 240281)
with papillate mantle edge, moderately long snout and

Page 38

THE NAUTILUS, Vol. 104, No. 2

R. S. Houbrick, 1990

Page 39

long, thick cephalic tentacles. Foot long, somewhat tu-
bular in shape, having narrow sole.

Synonymic remarks: The type lot of Cerithium macro-
stoma Hinds originally consisted of five specimens glued
to boards The one surviving specimen is labeled "prob-
able holot\pe": it is the figured specimen in Sowerby s
Thesaurus Conclnjliorum (fig. 219) and in Conchologia
Iconica (pi. 17, figs. 118a,b). The type of Colina gracilis
H. Adams has not been found. Considering that the de-
scription is ambiguous and no figure was presented, it
seems prudent to regard this ta.xon as a nomen duhium.
H. Adams (1866) noted its close resemblance to Colina
macrostoma and later remarked (1866:308) that "The
species I lately described as C. gracilis 1 find has been
since described by Mr. G. B. Sowerby under the name
of C. coarctata. ' Although the type of Cerithium coarc-
tatum has not been found, Sowerby s figures adequately
represent it, and indicate close resemblance to Colina
macrostoma. The many synonyms of this species lia\e
resulted from the failure of authors to appreciate the
wide range of intraspecific shell characters. Recognition
of the variability of Colina macrostoma was first noted
by E. A. Smith (1884:66-67), who suggested that Colina
costata, C. costiferum. C. pygmaea, and C. pupiforn}is
were all ". . . mere variations of one and the same shell, '
and who noted the variation in whorl number and shape
due to loss of the upper spire. While it may be difficult
to believe tliat extreme phenotypes such as the shells of
the nominal species shown in figures 6-41 are conspe-
cific, examination of many museum specimens and the
types of the nominal species listed in the above synonymy
reconfirms E. A. Smith's conclusion.

Colina selecta Melvill & Standen, 1898 (Figures 46,
47), is conchologically ver>' close to Colina macrostoma,
and may be a synonym of this species, but this remains
unresolved, due to lack of comparative material.

Discussion: This species is highly variable in shell shape
and sculpture. Older adult shells have a truncated, pu-
pate appearance due to decollation of early whorls and
erosion of the apex, and these look very different from
nondecollate shells (see figures 37, 38, 40, 41). Some
specimens lose more of the early whorls than do others.
When the apex of the spire has been broken off, the
animal closes the opening with a spiral plug and fre-
quently this is inset deeply within the old whorl (figures
33-36).

There is a great intraspecific difference in whorl num-
ber and in the number and strength of the axial ribs. A
range of phenotypes, from those having extremeK slen-
der shells (figures 8-10, 13-16, 19, 20) to those with
highly inflated midwhorls with wide axial ribs on their

shells (figures 29-34, 37, 38), may occur within the same
population. Shell sculpture is highly variable, but gen-
erally comprises 4-6 spiral cords of which the dominant
one frequently forms a keel on the middle of the whorl.
Spiral cords are crossed by 12-14 strong axial ribs pre-
senting an overall cancellate appearance (figures 19, 20,
39). Some phenotvpes have small nodes at the intersec-
tions (figures 8, 9,' 13, 14, 17, 18, 22, 23). The subsutural
spiral cord has many minute axial pleats. The body whorl
cords are flat and weakly sculptured with about 10 in-
cised spiral lines (figure 39). There is seldom any axial
sculpture on the bod\ whorl except for the axial pleats
beneath the suture. Shell color varies from light tan to
pinkish-brown, the body whorl and especially its incised
spiral lines, frequently being brown. These show through
on the inside of the outer apertural lip.

Shells from Japan and the Philippines (figures 6-25)
are slender and higliK elongate, while those from Aus-
tralia and the Indian Ocean (figures 26-41) tend to be
shorter, broader, and more pupate. These shorter phe-
notypes have been given the names Colina pupijormis
and Colina pygmaea. Initially, I was inclined to recog-
nize these nominal species as a subspecies of Colina mac-
rostoma because their shorter, more stocky shells tend
to occur in more southern and western geographical re-
gions. However, there are intergrades (figure 39), and
non-decoUate specimens from these regions bridge the
gap. Specimens from these parts of the range are fre-
cjuently badly eroded and uncommon in collections: when
more material is available for study, this putative geo-
graphic trend in morphology may become better doc-
umented. Currently, there is insufficient material to un-
equivocally resolve this issue, and it seems best to be
conservative and regard these nominal taxa as pheno-
t\pes of Colina macrostoma.

There is little information about the specific micro-
habitat of Colina macrostoma. In Japan and the Phil-
ippines, the habitat appears to be shallow, subtidal sea
grass beds (IISNM 343907, 273627). Although spa\\-n and
larvae of Colina macrostoma are unknown, its proto-
conch morphology (Figure 28) suggests a lecithotrophic
type of development (see Robertson, 1974; Jablonsky and
Lutz, 1980).

Geographic distribution (figure 45): This species ap-
pears to be confined to the Indo- West-Pacific, having a
distribution from Japan south through the Philippines,
Indonesia and tropical Australia, and into the Indian
Ocean as far west as eastern India and Ceylon.

Specimens examined: INDIA: W of Mandapam, Cull
of Mannar (ANSP 302283). CEYLON: (USNM 91248).

Figures 6-25. Colina macrostoma (Hinds) 6-7. iectotype of Cerithium macrostoma Hinds, Borneo, BMNH 1989181, length
10.1 mm; 8-10. Port Douglas, Queensland, Australia, LACM 116089, length 18.9 mm; 11-12. Iectotype of Cerithium (Colina)
Costatum A, Adams, BMNH 1989180, length 11.1 mm; 13-18. Sulu Archipelago, Philippines, LACM 76874, length 15.5 mm.
165 mm, 11.6 mm, respectively; 19-20. Shimoda, Shizuoka Pref., Japan. L,'\C:M 9:3102, length 19 0 mm; 21. holotype of Colina
pupijormis A. .^dams, Dumaguete, Philippines, BMNH 1989182, length 1'3.6 nmi; 22-23. Sulu Archipelago, Philippines, L.-KCM
76874, length 15 :3 mm; 24-25. Honshu, Japan, ANSP 240281, length 12.0 nmi

Page 40

THE NAUTILUS, Vol. 104, No. 2

R. S. Houbrick, 1990

Page 41

Figures 42-44. Colina macrostoma. scanning electron micrographs of radula 42. portion of radula with marginal teeth spread
open, bar = 40 /urn; 43. portion of radula with folded marginal teeth, bar = 40 iim, 44. detail of lateral and rachidian teeth, bar
= 20 Mill.

BORNEO: (type-specimen, Borneo (BMNH). JAPAN:
Shirahama, near Shimoda, Kii, Shizuoka Pref., Honshu
(LACM 93102); Ikenedan (BPBM 229662); Shirahama,
Kii, Shizuoka Pref., Honshu (MCZ); Oshima. Osumi,
Honshu (USNM 343907, 273627, MCZ); Hachijo Shima,
off Tokyo (ANSP 2402S1, 240158, 240223); Kanada Bav,
Kyushu (USNM 91115); Banda, Boshiu (ANSP 65275,
MCZ); Hirado, Hizen, Kvushu (USNM 343908, ANSP
1217). RYUKYUS: Loo Choo Ids (ANSP 195629); Ada
Village, Kumigami Prov., Okinawa (ANSP 320695).
PHILIPPINES: Laminusa, Siasi, Sulu Archipelago

(LACM 76874), WESTERN AUSTRALIA: North West
Cape Reef, Yardie Creek to Tantabiddi (WAM 1020-
84); Mangrove Bay, North West Cape (WAM 1021-84).
QUEENSLAND, AUSTRALIA: Grays Bay, Bovven,
Queensland (AMS CI 17180); 2 mi N of Ellis Beach,
Queensland (AMS CI 17178); Mission Beach, Queensland
(AMS C17177); Clump Pt, N Mission Beach, Queensland
(BMNH); Dunk Id, Queensland (ANSP 140135. 140136);
Four Mile Reef, 4 mi S of Port Douglas (AMS CI 17175);
headland between Kings & Queens Beaches, Bowen (AMS
C117169, 117173); Lindeman Ids, N of Mackay (AMS

Figures 26-41. Colina macrostoma (Hinds). 26-27. holotype of Colina pygmaea H. Adams, Borneo, BMNH 1878.1.28.32, length
10 1 mm; 28. protoconch and early whorls, AMS C117177, total length 3 mm; 29-30. N. Mission Beach, Queensland, .Australia,
BMNH, length 10.7 mm; 31-34. Ellis Beach, Queensland, Australia, AMS C117178, lengths 95 mm, 99 mm, respectively; 35-
36. N. Mission Beach, Queensland, Australia, BMNH, length 8 3 mm; 37-38. Ellis Beach, Queensland, Australia, AMS C117178,
length 9.6 mm; 39. Port Douglas, Queensland, Australia, AMS CI 17177, scanning electron micrograph, length 9.8 mmm; 40-41.
Hinchenbrook Id., Queensland, Australia, AMS, length 9 3 mm

Page 42

THE NAUTILUS, Vol. 104, No. 2

20- 40- 60" 8tf

Figure 45. Geographic distribution of Colina species.

100"

120

140

160°

C178174); Hinchenbrook Id, Queensland (AMS); Thurs-
day Id, Torres Strait, Queensland (BMNH 8212697).

Colina selecta Melviil & Standen, 1898
(figures 46, 47)

Colina selecta Mclvill & Standen, 189«:31, pi. 1, fijr. 2 (Holo-
t\pe: Manchester Museum, 1.5 1 ini'i; Type locality; Ma-
dras, India).

Description: Shell (figures 46, 47): Shell turreted, elon-
gate, narrow comprising about 12 convex whorls having
overall cancellate sculpture. Protoconch unknown. Early
teleoconch whorls with 3-4 four spiral cords. Adult te-
leoconch whorls scul[)tured with 5 spiral cords crossed
by 14-1,5 axial ribs and with siibsutural cord pleated
axially. Suture impressed. Body whorl elongate, con-
stricted, with about 10 flattened spiral cords, but lacking
axial sculpture. Aperture narrow, ovate, with slight si-
phonal constriction and short, reflected canal and smooth
outer lip. Clolumella concave with slight callus. Shell color
%\hitish-gray to tan. Operculum, radula and animal un-
known.

l)!-.rii';si<in: This species is based solely upon the type
'uii (i;il .'im prising two specimens. It is mori^hologi-
i :iil ■ loM- i(, Molina macroslotna with v\hich it is geo-
grapl.'. .liv svnipatric In India. Mclvill & Standen (1898:
31 pon.i, .! iiiif th, resemblance of Colina selecta to Coli-

na macrostoma (cited as C. taeniatum), but noted that
it was not as pupiform in shape, and not as nodulated
transversely. Colina selecta has highly cancellate sculp-
ture, a greater number of axial ribs, and an unflaring
aperture. Considering the extreme phenotypic variation
observed in Colina macrostoma, it is not unreasonable
to suggest that Colina selecta may be mereK another
variation of the former species. However, Colina selecta
is known only from a few specimens, and as no specimens
of Colina macrostoma with intermediate shell sculpture
bridging the gap have been seen, it seems best to regard
Colina selecta as a good species until evidence is pre-
sented suggesting otherwise.

Geographic distribution (figure 45): The range of this
species is limited to the t\pe localit\ in Madras, India.

Specimens examined: INDI.\: Madras (type-specimen,
Manchester Museum); Krusadi, Madras (paratope, NMW
55158).

Colina pingttis (A. .\dams, 1854)
(figures 48-76)

C'cnlhimu pin^uis .\ .\daMis, IS.")l:S(i ll.frtn(\ |H-, Iktc des-
ii;natcd: HMNII 1989200 1. 17 7 nun, l paralectotypes;
BMNH 19S99()() 2-5; Type loc,ilit\ I'hilippines [in error];
here cdirrclcil lo Cape Natal. .Snulli Africa);

R. S. Houbrick, 1990

Page 43

Figures 46-4-7. Colina selecta Mel\'ill & Standen. 46. liolotvpe, Madras, Manchester Museum, 15,1 mm length; 47. paratype,

NMW 55158, 10,5 mm length.

Cerilhinm pinguc A, Adams, Sowerby, 1855:877, pi, 184, fig.
217; Sowerby in Reeve 18Wi: pi. 17, fig. 121.

Cerithium (Colina) pingue A. Adams. Tryon, 1887:141, pi, 26,
figs, 8,9,11; Abrard, 1942:61, pi. 6, fig. 28.

Cerithium taeniatum Sowerby in Reeve, 1866: pi. 17, fig. 119
(Holotype: BMNH 1989199; Type-locality: Cape Natal,
South Africa, 16 mm (not Cerithium taeniatum Quo\ and
Gaimard, 1834:11.3); Sowerby, 1866: pi. 17. fig, .320; 1866,
pi. 12 [supplementar\], fig. 320,

Cerithium contraclum Sowerb\, 1855:877, pi, 184, fig, 218
(Holotype: BMNH 1907.10,28,129, 17 mm; Type localit> :
unkown; not Cerithium contractum Bellardi, 1850); Sow-
erby in Reeve, 1866: pi. 17. fig. 120.

Cerithium crumena Bayle, 1880:245-246 (replacement name
for Cerithium contractum Sowerb), 1855).

Colina perimensis Jousseaume. 1930:28.5-286 (replacement
name for Cerithium taeniatum Sowerby, 1866).

Description: Shell (figures 48-73): Shell moderately
elongate, decollate (adults usualK' missing 3-4 vvhoris),
adults with plug-like apex; upper whorls v\ith concave
outline, conve.x, swollen middle whorls, and constricted
body whorl. Shell shape pupate due to decollation of
early whorls and formation of secondary apex. Proto-
conch comprising about 2 imsculptured smooth w horls
with slightly sinuous apertural lip. Early teleoconch whorls
sculptured with 3-4 spiral striae; teleoconch whorls con-
cave, pendant; penultimate whorl convex. Adult whorls

with overall sculpture of fine spiral striae and incised
lines and with 10-14 large axial plicae or ribs on lower
half. Body whorl large, elongate, tightly constricted, and
weakly sculptured w ith subsutural plicae and spiral cords.
Suture moderateK impressed. Aperture narrowly ovoid
with short, broad weakly reflexed anterior canal, and
smooth dilated outer lip. Columella concave, smooth w ith
slight wash at aperture; 2 internal columellar plaits ex-
tending up pillar. Shell color white, with large tan to
brown blotches or maculations; thin brown stripes on
body whorl appearing as stripes or brown checks at ap-
erture inner lip; axial ribs frequently white. Periostracum
tan, thin. Operculum (Figures 67, 68) corneous, ovate,
paucispiral with eccentric nucleus.

Animal (figures 1-5): Body comprising about four
whorls. Long, wide columellar muscle 2 whorls in length;
anterior columellar muscle with 2 deep grooves (figure
3, cmg) corresponding to columellar plaits of shell pillar.
Ophalic tentacles moderately elongate, but fat and very
broad with large peduncular eyes (figure 2); snout mod-
erately elongate, bilobed at tip. Inhalant siphon slightly
protruding, with large papillae at edge and darkly pig-
mented undersurface. Foot large; epipodial skirt fringed
with many short papillae (figure 1, p) and having large,
posterior operculiferous lobe (figure 1, opl); sole with

Page 44

THE NAUTILUS, Vol. 104, No. 2

; i.n.rrs 4-8-55. Colina pinguis and types of nominal species. 48-49. lectotype of Cerithium pinguis A. Adams from <^ape Natal
a, RMNH 1989200/1, 17 7 mm length; 50-51. paralectotype of Cerithium pinguis. Cape Natal, South Africa, BMNH
_ f n.S mm length; 52-53. holotype of Cerithium taeniatum Sowerhy, Cape Natal, South Africa, BMNH 1989199,
Iti.w niiT. lei.gln, 54-55. liolotvpe of Cerithium amtraclum Sowerhy, BMNH 1907.10.28.129, 17.0 mm length.

R. S. Houbrick, 1990

Page 45

Figures 56-66. Colina pinguis, showing variation in pattern and sculptural niorpholi)g> . 56-57. Port Alfred, South Africa, DMNH
16073, 17.3 mm length; 58. shell cut axially to show weak columellar fold, 16.0 mm length; 59-60. Port Alfred, South Africa,
DMNH 16073, 18.5 mm length; 61-62. Djibouti, Djibouti, MNHNP, 18.5 mm length; 63-64. Port Alfred, South Africa, DMNH
16073, 16.9 mm length; 65-66. Djibouti, Djibouti, MNHNP, 15.8 mm length.

Page 46

THE NAUTILUS, Vol. 104, No. 2

R. S. Houbrick, 1990

Page 47

Figures 74-76. Colina pinguis, scanning electron micrographs of radula (Port Alfred, South Africa, DMNH 16073). 74. general
view of ribbon with marginal teeth spread open, bar = 6 nm; 75. half row, bar = 6 ^m; 76. detail of lateral and rachidian teeth,
bar = 40 nm.

Figures 67-73. Colina pmguis. scanning electron micrographs of shell and operculum (Oman, BMNH) 67-68. attached and
free sides of the operculum, respectively, bar = 0 9 mm; 69. early juvenile whorls (protoconch missing), bar = 0.5 mm; 70-73.
lateral and apical views of decollate shell apices, showing broken original shell and replacement plugs, bar (70, 72) = 0.9 mm, bar
(71, 73) = 0.,5 mm.

Page 48

THE NAUTILUS, Vol. 104, No. 2

large, centrally-located, slit-like metapodial mucus gland
(Figure 1, mmg) extending deeply within central foot.
Propodial mucus gland (figures 1, 4, pmg) crescent
shaped, slit-like, extending deeply into front edge of foot,
and overlain b\ thin epithelial flap.

Radula (figures 74-76): Radula about one-fifth the shell
length. Rachidian tooth (figure 76) with square basal
plate ha\ing small central bottom projection and with
slightly raised fold at each lateral edge; cutting edge
convex, with large, central spade-shaped cusp flanked on
each side with 2, sometimes 3 small, blunt denticles.
Lateral tooth (figure 76) rhomboid-shaped with mod-
erate lateral extension and having wide posterior pillar-
shaped extension with small bead; cutting edge com-
prising small inner denticle, large pointed cusp and 3
small outer denticles. Marginal teeth (figure 76) spat-
ulate, broad at middle, curved at tips; inner marginal
tooth with 2 inner denticles, long pointed central cusp
and 2 outer denticles; outer marginal tooth same but
lacking outer denticles.

Synonymic remarks: This species has four synonymous
names. The type lot of Colina pinguis comprises five
specimens, which vary greatly in sculpture and shape.
The largest specimen (figures 48, 49), which corresponds
to Sowerby's (1855) fig. 217 in the Thesaurus, also ap-
pears to be the figured specimen of Colina pinguis in
Conchologia Iconica (1866: pi. 17, fig. 121) and is here
designated as the lectotype. The second largest specimen
of the type lot (figures 50, 51; paralectotype) was figured
by Sowerby (1866) in Conchylogia Iconica on the same
plate (fig. 120), and named Cerithium contractum, but
this name is preoccupied. The holotype of Colina taenia-
tum (name preoccupied) is a weakly sculptured, non-
decollate specimen (figures 52, 53) of Colina pinguis.
which shows some brown spiral stripes not seen in the
type lot. Both Colina taeniatum and Colina contractum
were given replacement names by Jousseaume (1930)
and Bayle (1880), respectively.

Discussion: Colina pinguis is easily distinguished from
its congener, Colina macrostoma, by its larger, wider,
and heavier shell. Its upper whorls are concave and pen-
dant, sculpture is not usually as cancellate as in Colina
macrostoma, and it never attains the narrowly elongate
form of that species. There is no geographical overlap
between the two species.

Examination of many lots of Colina pinguis from South
.\frica and from more northern locations reveals consid-
erable sculptural variety within populations (see figures
48-66). Moreover, older, decollate individuals (figures
48-55) have a fatter, more .squat aspect than younger,
more fusiform individuals with retained spires (figures
56-66). Specimens from the Red Sea (figures 61, 62, 65,
66) and northwestern Indian Ocean appear to be more
darkly colored than those from South Africa.

This species, commonly recorded from South Africa.
pr .1 inix occurs in suitable habitats all along the north-
eustern I'ncan coast, which is more poorly known. Spec-
imens In; tn Kr-rva indicate that southern populations are

probably continuous with more northern ones in the Red
Sea. Colina pinguis lives gregariousK in lower midtidal
pools, chiefly in clumps of coralline algae (Kilburn &
Rippey, 1982:54). A label accompanying specimens from
Oman in the British Museum (Natural Histor\ ) collection
also cites coralline algae as the habitat. Bosch and Bosch
(1982:49) record Colina pinguis occurring on sand and
algae at low tide in Oman.

The spawn of Colina pinguis has been briefly de-
scribed and illustrated b\ Kilburn and Rippey (1982:55,
fig. 20), who recorded that it is deposited among branches
of coralline algae, and consists of a gelatinous mauve
string. Their depiction of the egg ribbon shows that it is
small, about 10 mm in length, and contains few, mod-
erately large eggs. This feature, plus the unsculptured
protoconch, and the patchy, nearly disjunct geographic
distribution of the species suggest a direct type of de-
velopment, but this needs confirmation.

Fossil records: This species has been recorded from the
Pleistocene of Somalia (Abrard, 1942:61, pi. 6. fig. 28).

Geographic distribution (figure 45): Colina pinguis
occurs along the eastern African coast from South Africa
north to Kenya, and then jumping north to the Red Sea,
the Gulf of Oman, and Persian Gulf, extending eastward
to Pakistan. The single records from Suez and the Persian
Gulf need reconfirmation.

Specimens examined: RED SEA: Suez, Egvpt (USNM
23227). AFFARS & ISSAS: Djibouti (MNHNP). OMAN:
Muscat (USNM 798223); Wadi Haart, near Salalah
(BMNH); Slud, near Salalah (BMNH). PERSIAN GULF
(MNHNP). IRAN: Chah Bahar (MNHNP). PAKISTAN:
Manani Rocks, Karachi (BMNH). KENYA: Mombassa
(USNM). SOUTH AFRICA: Albany (USNM 97995); Port
Alfred, Eastern Cape (USNM 186801, DMNH 16073);
Port Gonubie (USNM 845781); Cape Natal (BMNH).

DISCUSSION

Shell Morphology and .4natomy: There are several
notable diagnostic shell features of Colina species. This
genus is easily identified by its unusual fusiform, fre-
quentK- slender, pupate shell ha\ing inflated midwhorls
and a highly constricted bod\ whorl. EarK whorls are
concave in outline, while adult midwhorls are inflated
and usually sculptured with large axial ribs. The bod>
whorl is constricted and narrow, relativel\- weakK sculp-
tured, and has an elongate, o\ate aperture. In addition,
the upper \\ horls are frequently decollate and a second-
ary apex (figures 70-73) is added as a plug, enhancing
the pupate shape.

The truncated apex is a distinctive feature of the shell
of Colina species, .\lthough decollation and formation
of a secondary apex occurs in shells of Cerithidea species,
family Potamididae (Houbrick, 1984), this phenomenon
is not seen in other genera of the Cerithiidae nor in
members of other cerithioidean families.

The protoconch of Colina macrostoma (figure 28) is
smooth, comprises one whorl, and is indicative of direct

R. S. Houbrick, 1990

Page 49

development. It differs totally from the elaborately sculp-
tured protoconchs of litiopids (see Houbrick, 1987b: 12,
figs. S, 10) and is unlike those of most Bittium and Cer-
ilhiiim species that have pelagic veliger larvae. However,
Cerithium species with direct development have pro-
toconchs similar to those in Colina (see Hout)rick, 1973;
1974). Cossmann's (1889:61) assertion that the proto-
conch of Colina was unlike those of cerithiids and more
like those of cerithiopsids such as LovcncUa. is probably
due to his mistaken notion that the secondary ape.x of
decollate Colina individuals (see figures 70-73) he ex-
amined was the real protoconch.

EarK whorls of Colina species are sculptured with
three to four spiral cords (figure 69), the two anterior
ones being strongest. Kilburn and Rippey (1982:55, fig.
19) noted that "Juveniles resemble very narrow, very
high-spired trochids, with a flattened base and short,
sharp siphonal spout." Immature Colina pingttis shells
have a concave outline, and look very much like adult
Trochocerithium species (see Houbrick, in press).

Of the three Colina species recognized herein, Colina
pinguis has the largest, widest shell (figures 48-66). In
contrast, Colina macrostoma (figures 6-41) commonly
is highly elongate and slender, some morphs attaining
almost a nail-like shape (figures 8-10, 14-16, 19-20). This
species also has the most variable shell sculpture within
the genus. The shell of Colina selecta (figures
46, 47) has a sculpture that closely resembles Colina
macrostoma, but is more finely cancellate.

Anatomy: Most of the anatomical knowledge about Co-
lina species has been derived from an examination of
Colina pinguis; thus, anatomical characters may be aug-
mented and/or redefined as the soft parts of other species
become known.

Externally, the animal has an overall certithiid aspect
and comprises about four w horls. The visceral coils con-
sist of a typical digestive gland and gonad, a stomach
about one whorl in length, and a moderately large kid-
ney. The columellar muscle (figure 3, cm) is long and
broad, extending nearK two whorls in length, and has
two deep anterior grooves (figure 3, cmg) that corre-
spond to the columellar plaits of the shell. The long, broad
columellar muscle seen in Colina species does not occur
in Bittium species or in litiopids. The dorsal mantle edge
is fringed with papillae (figure 2, mp).

The large foot has an epipodial skirt (figure 2, eps)
fringed with papillae along its lateral edges and has a
large, posterior papillate operculiferous lobe (figure 1,
opl), similar to that seen in many Bittium species. The
operculum (figure 1, op) overlies the operculiferous lobe.
The foot is probably longer and more slender than de-
picted in figure 1, and the epipodial papillae more ten-
tacular in living snails. The epipodial papillae are short
(at least in preserved specimens), and do not appear to
be as elongate as in litiopids. In this respect, they are
more like the epipodial papillae observed in some Bit-
tium species (Houbrick, pers obs. ). The operculigerous
lobe of the posterior epipodium of Colina species is also

similar to that observed in Bittium species (see Marcus
& Marcus, 1963:75, fig. 80; Houbrick, pers. obs.).

The propodium is crescent shaped (figure 1) and has
a long papilla at each side followed by the smaller pa-
pillae (figure 1, p) of the epipodial skirt. The leading
edge of the propodial sole has a deep slit along its leading
edge overlain by a thin propodial flap (figures 1, 2, 4, f).
This slit leads into a large deep propodial mucus gland
(figures 1, 4, pmg) in the front of the foot. The mor-
phology of the propodial mucus gland of Colina pinguis
is nearly identical to that of litiopid and Bittium species.

The sole of the foot (figures 1, 3, s) is highly glandular,
having many transverse furrows and a deep longitudinal
slit (figures 1, 2, ms) beginning at the middle of the foot
and extending back to its posterior edge. The slit marks
the entrance to a massive metapodial mucus gland (fig-
ures 2, 3, mmg) having a large duct (figure 3, d) that
extends deep into the headfoot to the pedal ganglia.
Similar metapodial mucus glands also occur in litiopids
(see Houbrick, 1987b: 12, figs. 7, 12) and in some Bittium
species (Marcus & Marcus, 1963:75, fig. 80; Houbrick,
pers. obs). In litiopids and in some Bittium species, this
gland produces a strong mucus thread, anchoring the
animal to the substrate, as seen in Colina pinguis. It is
therefore reasonable to infer that it has the same function
in other Colina species.

The ovate, corneous, paucispiral operculum (figures
67, 68) is similar to the opercula of cerithiid species such
as Bittium Gray, Cerithium Bruguiere, Ctijpeomorus
Jousseaume, Rhinoclavis Swainson, and Pseudovertagus
Vignal, differing only in having a subterminal nucleus.

The cephalic tentacles are very fat, wide, and stubby,
each bearing a large eye at its peduncular base. The
snout (figures 1, 2, sn) is short and has a bilobed tip.
Both the snout and cephalic tentacles are probabK longer
in living animals.

The dorsal mantle margin has a double fringe, but is
smooth ventrally. The upper dorsal part of the double
fringe is smooth, while the lower part bears long papillae.
This fringed dorsal mantle edge occurs among all mem-
bers of the Cerithiidae. but is absent in litiopids. The
exhalant siphon protrudes slightly, and the dorsal mantle
edge adjacent to the inhalant siphon is marked by a deep,
left-central cleft, which has enlarged, protruded papillae
and a darkK pigmented undersurface.

The mantle ca\ ity is deep and spacious. A ver\- broad
bipectinate osphradium (figure 5), comprising tall pec-
tens, tapers posteriorly and extends nearly the full length
of the ctenidium. The ctenidium is as long as the mantle
cavity, twice as broad as the osphradium, and comprises
long, tall leaflets, narrow at their left leading edges and
becoming long and shallow to the right. The hypobran-
chial gland is thick and glandular and as broad as the
ctenidium. The rectum is half as wide as the hvpobran-
chial gland and is filled with many white, ovoid stacked
fecal pellets. The male pallial gonoduct is open, ty pically
cerithioid, and has many transverse glandular folds along
its entire length. These probably comprise the prostate
and possibly a spermatophore forming organ, respec-

Page 50

THE NAUTILUS, Vol. 104, No. 2

lively. No spermatophores were found, but as they are
t>pical of teritliioideatis. the\ prohabK occur in this
group as well. The fcmaie paliial o\ ickKts are unknown.
.■\ltliough the nianllc cavity organs of Colina pingiiis are
t\pically cerithioid, the ver\ broad bipectinate osphra-
dium is unusual, especially in such a small snail; other-
wise, it is typical of those seen in Cerithiuni species
(Marcus & Marcu.s, 1964). In litiopids (Houbrick, 1987b:
13) and some Bittium species (Marcus & Marcus, 1963:
78-79, fig. 88, y) the osphradium is monopectinate, while
in other Bittium species it is a simple ridge (Houbrick,
pers. obs.). The morphology of the ctenidial filaments in
Colina piiiguis is very similar to those seen in litiopid
and Bittium species.

The buccal mass is moderately large, filling the short
snout. There are two semilunar shaped prismatic jaws.
A pair of thin, tube-like salivary glands coil tighti\ in
front of the nerve ring, but extend through and originate
behind it. The taenioglossate radula (figures 42-44 &
74-76) of Colina species is of moderate size, about one-
seventh the shell length. The rachidian tooth is square,
having a cutting edge with a large pointed central cusp
flanked by two blunt denticles on each side. The basal
plate of the rachidian tooth has a small median posterior
e.xtension and a weak raised fold at each lateral edge.
The lateral tooth is rhomboid-shaped, having a wide,
posterior pillar-shaped extension on the basal plate and
a moderate lateral extension. The marginal teeth are
spatulate with curved serrated tips. The shape and den-
tition of the rachidian tooth of the radula of Colina
species (figures 44, 76) are unlike those of litiopids and
man\ Bittium species, which have hourglass-shaped bas-
al plates (see Houbrick, 1987b:12, figs. 13-14; 15, figs.
18-19; Marcus & Marcus, 1963:75, fig. 81): in Colina
species, the rachidian is more squarish, as in many Cer-
it Ilium species.

The stomach and anterior alimentary tract of Colina
pinguis are l\pical of cerithiids and litiopids. Immedi-
ately behind the nerve ring, the midesophagus is twisted
and expands to form a large esophageal gland whose
inner epithelium is thrown into many transverse ridges.
E.sopliageal glands also occur in Cerithiuni. Clypcomo-
rua and Bittium species (Houbrick, 1974, 1985, in press)
and in litiopids (Houbrick, 1987b). The posterior esoph-
agus is a narrow straight tube. The large stomach is lined
interiorly with many small ridges and grooves torming
complex sorting areas. A raised central pad divides the
sorting area; a cuticular gastric shield and a short, but
distinct, style sac are present. Although a crystalline style
was not observed in preserved specimens, short style sacs
and styles occur in Cerithiuni and Clypcomorus species
(Houbrick, 1985). Examination of fecal pellet contents,
;ind the morphology of the radula and alimentary system,
' ariiciilariy the sorting surface, gastric shield, and style
' "I the stomach, suggest that members of this genus
' .i!ii:i. 'uhagous herbivores.
I 'i' nt r\oii> system is epiathroid. The right cerebral
aini I '. .r,;il ganglia are closely joined, but there are very
long M-. l.io-pcdil connectives. The pedal ganglia lie

deep in the foot, each having a statocyst on its inner side.
The supraesophageal connective is very long. The gan-
glia of the nervous system are thus typically cerithioid
in layout, but the long cerebro-pedal connectives are
notable.

The kidney extends posteriorly, about one-half of a
whorl in length. Only one lobe was discerned, and there
is a large kidney opening into the posterior mantle cavity.

Ecology: Very little has been recorded about the hab-
itats and life histories of Colina species. In the original
description of the genus, H. & A. Adams (1854:286)
remarked that "The species known are inhabitants of
deep water, living in coarse sand. ..." This statement
appears to be erroneous, as museum records of all species
examined cite intertidal to shallow subtidal habitats. The
few data available from collection records indicate that
Colina species are closely associated with weedy or algal
substrates.

Colina species appear to use a thread of mucus pro-
duced by the large metapodial mucus gland to anchor
themselves to their algal substrate in much the same way
that litiopids (Houbrick 19S7b:ll) and some Bittium
species do (Houbrick, pers. obs). This phenomenon has
been observed by Kilburn and Rippey (1982:55). who
recorded that Colina pinguis ". . . anchors itseli with
elastic threads."

Conclusions: Colina is not a speciose genus and does
not have an extensive fossil record, only one Pleistocene
record being recorded (Abrard, 1942:61). Although some
external anatomical characters such as the epipodial skirt
fringed with papillae, a large papillate operculiferous
lobe, and deep propodial and mesopodial mucus glands
are similar to those seen in species of Alaba H. & A.
Adams 1853, and Litiopa Rang, 1829, family Litiopidae
(see Houbrick, 1987b), the combination of shell and other
anatomical features are more like those observed in
members of the Cerithiidae, especialK' in Bittium species.
Iri addition, some Bittium species have a mesopodial
mucus gland. These include a shell with a distinct si-
phonal canal and a protoconch similar to those Bittium,
Cerithiuni. and Clypcomorus species with direct de\el-
opment. The attached surface of the operculum of Col-
ina (Figure 67) does not have the spiral ridge seen in
litiopid species (see Houbrick, 1987b:10, fig. 1), but is
more like those of the cerithiids (see Houbrick, 1974;
1985). Other anatomical characters of Colina. absent in
litiopids, include the fringed papillate dorsal mantle edge,
a long broad columellar mu.scle, short, fat cephalic ten-
tacles (which may be artifactual), a squarish rachidian
tooth, and coiled sali\ary glands (straight tubes in litiop-
ids). With the exception of the long, broad columellar
muscle and short, fat, cephalic tentacles, these characters
are present in Bittium. Cerithiuni. and Clypcomorus
s|)ecies.

.•\s the temale paliial oN-iduct anatomy of Colina is
unknown, comparison of paliial oviducts of cerithiid gen-
era thought to be closely related to it is not possible.
Ne\crtlieless, the known shell, radular. and anatomical

R. S. Houbrick, 1990

Page 51

cliaracters of Colina species clearly suggest an assign-
ment of this genus to the Cerithiidae, subfamiK Ceri-
thiinae Ferussac, 1819, close to the general Bittium Gra%',
1847, Cerithium Bruguiere, 1789, and Clypeomorus
Jousseaume, 1888. As more knowledge of the smaller-
sized and obscure cerithiid genera is accumulaletl, these
data, along with those from Colina. can be utilized in a
more complete cerithioidean ph\logenetic analysis (see
Houbrick, 1988). Only then will the generic relationships
become clearer and have a more substantial basis.

ACKNOWLEDGEMENTS

For loans of types and specimens I thank the curators
and collection managers of the follow ing museums: Dr.
Riidiger Bieler (DMNH), Dr. Philippe Bouchet
(MNHNP), Dr. George Davis (ANSP), Mr, Ian Loch
(AMS), Dr. James McLean (LACM), Dr. Richard Petit
(Manchester Museum), Ms. Alison Trevv (NMW), Ms.
Kathie Way (BMNH), Dr. Fred Wells (WAM). I thank
Mr. Victor Krantz, Smithsonian Photographic Services.
The Smithsonian Scanning Electron Microscope Labo-
ratory assisted w ith preparations of micrographs. I am
grateful to Ms. Shelley Greenhouse for checking the orig-
inal draft of this manuscript for errors.

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Adams, A. 1854. A monograph of Cerithidca. a genus of
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Adams, A. 1853-1855. The genera of Recent Mollu,sca 1(1-
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(1855). London.

.^dams, H. 1866, Descriptions of a new genus and a new
species of niollusks. Proceedings of the Zoological Society
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Adams, H. 1867, Descriptions of new species of shells. Pro-
ceedings of the Zoological Societ\ of London. 1867. p.
307-309, pi. 19, fig. 20.

Adams, H. and A. Adams. 1853-1858. The genera of Recent
Mollusca; arranged according to their organization 3 \ols
London, 389 p., 138 pis.

Bayle, E. 1880. Liste rectificative de quelques nonis de genres
et d'especes. Journal de Conch\liologie 28(3):240-251,

Bellardi, L. 1850. Raisonne des fossiles nunnnuliti(|ues du
Conte de Nice. Memoirs de la Societe Geologique de France
(serie 2) 4:205-300, pis.

Bosch, D. and E. Bosch. 1982. Seashells of Oman. Longmans,
New York, 206 p., illustrated.

Bruguiere, J. G. 1789, 1792. Encyclopedic methodique: his-
toire naturelle des vers. l(l):l-344 (1789); l(l):345-758
(1792).

('oinad, T. .\, I S6() Ocsrriptinusol new spccii-s of Cretaceous
and Eocene fossils of Mi.ssissippi and Alaliarna, Journal of
the .\cadem\ of Natural Sciences, Philadeiplii.i (series 2)
4:275-298, pis. 46-47,

Cossmann, M. 1889. Catalogue illu.slre des eociuilles iossiles
de I'Eocene des environs de Paris Societe Ro\ale Mala-
cologique de Belgique, Part 4:380 p , 12 pis

Cossmann, M. 1906. Essais de paleoconchologie comparee,
X'olume 7, Paris, 261 p., 14 pis.

Delrance, \! J L 1816-18.30. Dietionnaire des sciences iia-
turelles. . . . Paris. 60 vols

Ferrussac, J, B. L. d'A de. 1819, Histoire naturelle general et
particulire des mollusques terrestres et flu\iatiles. \ol, 1
Paris. (1-28): 128 p., 162 pis.

Fischer, P, 1880-1887. Manuel de conchyliologie el de pa-
leontologie conein liologique ou histoire naturelle des
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Goldfuss, G, .\.. von. 1820, Handhuch der Zoologie 2, N'urn-
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Ciray, J. E. 1847. The classification of the British Mollusca h\
N. E. Leach, M D .Annals and Magazine of Natural His-
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Hinds, R, B, 1844, Zoology of the voyage of HM.S. Sulphur,
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the vears 1836-42, X'olume 2. Mollusca. London, 72 p.. 21
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Houbrick, R. S, 1973. Studies on the reproductiw l)iology of
the genus Cerithium (Gastropoda: Prosobranchia) in the
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Houbrick, R, S, 1985. Genus C7i/pcr;f?if;r(/.s Jousseaume i(!er-
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Houbrick, R, S, 1987a. Description of a new giant Ataxoeer-
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Houbrick, R, S, 1987b, Anatomy of Alalia and Litiopa (Pro-
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Jablonski, D. and R. A. Lutz. 1980. Molluscan larval shell
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THE NAUTILUS, Vol. 104, No. 2

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Tate, R. 1894. L'nrecorded genera of the older Tertiar\ fauna
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THE NAUTILUS 104(2):53-56, 1990

Page 53

Two Unusual Gastropods From Late Pliocene Lakes in Northeast
Nebraska

Harold C. Pierce

Research Associate

University of Nebraska State Museum

Lincoln, NE 68688, USA

ABSTRACT

Lyninaca {Acella) haldanani Binney 1867 and Acroloxus colo-
radoensis (Henderson 1930), rare as living species and unusual
as fossils, are found in a late Pliocene lacustrine assemblage in
northeast Nebraska in association with two extinct taxa, Ont-
alodiscus paltersoni (F. C. Baker, 1938) and Deroceras aenig-
ma, Leonard 19,50. Climatic interpretation, based on the re-
maining mollu,scan fauna, suggest the late Pliocene climate,
immediately preceeding the first glacial advance, approximat-
ed that of the present.

curring during pluvial intervals on the High Plains, sug-
gesting additional investigations involving other known
fossiliferous deposits in the immediate area. A second
locality, some 6.5 kilometers (4 s.m.) north of the Clark
Mills Locality, the Niekles Gravel Pit, UNSM KX 109
(Figure 1), was sampled, largely on the report of a late
Blancan microvertebrate fauna, an associated ash, and
an overlying till (Voorhies, pers. comm.). Samples pro-
cessed from this locality produced a second molluskan
fauna, w hich matched verv well the Clark Mills fauna.

During the 1988 field season. Dr. K. G. Goodwui, De-
partment of Geology, Llniversity of Nebraska-Lincoln,
discovered fossiliferous lacustrine sediments in Knox
County, Nebraska associated with a volcanic ash and
underlying a glacial till. Dr. M. R. Voorhies, Curator of
Vertebrate Paleontology, University of Nebraska State
Museum, quarried and processed approximately one
metric ton of sediment from the locality now known as
the Clark Mills Local Fauna, UNSM KX 143 (figure 1).
Mammals recovered indicated a late Blancan age (2.0-
2.5 MA) for the fauna, and paleomagnetic analyses in-
dicate that the sediments were deposited in a reversed
magnetic field (Matuyama Reversed Epoch) (Voorhies
& Goodwin, 1989). On this basis, the ash is identified as
Pearlette Type B, fission-track dated at 1.97 MA (Boells-
dorf, 1973:39), hence, of late Pliocene age.

In addition to the mammals, an unusually diverse fish
fauna was recovered, to include such northern species as
walleye {Stizostedion vitrettm), northern pike (Esox, cf.
£. luciiis), muskellunge (Esox. cf. £. masqitinongij), and
an undetermined trout (Salmonidae, Gen. et sp. indet.)
(Voorhies, pers. comm). The mollusks recovered while
sorting for vertebrates were given to me for study. Fur-
ther collection of material from this locality in 1989,
collected at controlled stratigraphic intervals, was pro-
cessed specifically for mollusks and ostracods. The larger
gastropods were somewhat crushed, but all taxa were
identifiable with confidence. A generally typical cool
water fauna was identified, suggesting that cool, pluvial
conditions existed at time of deposition (table 1) This
fauna differed from the typical Pleistocene faunas oc-

•SD

BROWN

v..

r-^

^KX 109

•

.'-KX 14 3

Figure 1 Locality map of C:lark Nhlls Locality (KX 1-43),
NIckles Pit Locality (KX 109), l)oth Knox County, Nebraska,
and Sand Draw Locality (SU), Brown Counts, Nebraska.

Page 54

THE NAUTILUS, Vol. 104, No. 2

Table 1. Comparison of faunas of the Clark Mills Locality (KX 143), Nickles Pit Locality (KX 109) and Sand Draw Locality 6.
Frequency data: VR = 1; R = 2-5; F = 6-1.5; C = 16-50; A = 51-200; VA = >200. X = Reported b\ Taylor, 1960, from Sand
Draw, but not his complete list * = Extinct taxa, or taxa not known with certainty to still exist locally

I'auiuil list

KX 113

Lower

Up pel

KX 109

Sand Draw

\'alvatidae

Valvata lewisi Curier 1868
v. Iricarinata (Say 1817)

Planorhidae
Cijraidus parvus (Say 1817)
I'ronu'netiis cxacuous (Say 1821)
P. nmhilicatellus (Cockerell 1887)
Omalodiscus pattersoni (F. (;. Baker 1938)*
Planorlnda annigera (Say 1818)
Planorbella trivolvis (Say 1817)
//. anceps (Menke 1830)

L\ iMiiaeidae
Lyninaea hiirnilis Say 1822
L. palustris (Muller 1774)
/.. hnlitnoUlcs Lea 1841 (?)
/. Imlclciiiuni Binney 1867*

Pii\si(iae
Phijsclla gyrina Say 1821
P. sp. ianalina'i')
Phijsa jcnncs.si skinncri (Taylor 1954)*

Ancylidac

Acroloxus coloradocnsis (Hend. 1930)*
Fcrrissia mci'kiaiui (Stimpson 1863)*

Carscliiidae

(■/irychiiau cxigiiiiiu (Say 1822)
Liinacidac

Dcrocrras acnignia Leonard 1950*
Cen. & sp. indet.

Succineidae
cf. Sticcinea
Oxyloma sp.

Pupillidae
Caslrocopta pcniodun (Say 1821)
G. armifera (Say 1821) ' ablrreviata
G. contracta (Say 1822)
C. holzingeri (Sterki 1889)
Vertigo nvata Sa\ 1822
V. mdium ((Jould 1840)
Pupilla museorum (Liim. 1758)*
Pnpoidi's allrilabris (C. B. Adams 1841)

\ allnniidae
Vallonia pidrhclla (Muller 1774)
\'. parvula Sterki 1893

/nnitidae

Haiiiiiia mmusctda (Binney 1840)

1- in'odiiiilidae

ililiroihsciis .•iinglpyamis (Pilsliry 1890)

Gastropods
Aquatic

F
C

A
C

R
C

R
VR

Terrestrial

R
R

R
F
F

VA
C

F
R

A
A
C

C
F

C
R
R

F
R

A
R

A
C

F
X
F

X
X

\'R

H. G. Pierce, 1990

Page 55

Table I . ( 'iintiriurd

FauMul list

K.\ 143

l.uuer

Ippt-r

K\ 109 Sand Drav

Bivalves

Uninnidae
Gen. & sp. indet,

Spliaeriidae
Pisidium. cf. P. ualkcri Sterki
P.. cf. P. ventrkusuni Prime 1
Sphaeritim partumeium (Say
S., cf. S. simile (Say 1816)

Ostracodes

Large candnnid

Plant
Cliara sp,, oogonia
Rhus sp., sumac nutlets
C'cltis sp , liackherr\ nutlets

1895
851
1822)

A
C
F

A
C

C
VA

C
C

F
F

and included a good sampling of the terrestrial gastro-
pods that were poorly represented in the Clark Mills
fauna. Table 1 compares these two faunas and a fauna
collected at Taylor's (1960:34) Sand Draw Locality 6,
Brown County Nebraska, which is supplemented by oth-
er taxa reported by Taylor from Sand Draw Localities.

Two unusual gastropod species make the Knox County
faunas remarkable. The fauna of the oldest lacustrine
section at the Clark Mills Locality, beneath the ash, in-
cluded three incomplete (2.5-4 whorls), but readiK iden-
tifiable Lymnaea (Acella) haldemani Binney, 1867 (fig-
ure 2) and eleven Acroloxus coloradoensis (Henderson,
1930) (figures 3, 4). Although no L. haldemani were
recovered at the Nickles Pit Locality, that fauna did
include A. coloradoensis. Two extinct species were also
found, Omalodiscus pattersoni (F. C. Baker 1938), re-
covered only at the Clark Mills locality, and Deroceras
aenignia Leonard 1950, found at both localities. For L.
haldemani, this represents a considerable extension in
range, both geographic and stratigraphic. Records of liv-
ing specimens are restricted to the Great Lakes drainages
and the Hudson River system (F. C. Baker, 1928:270;
LaRocque, 1968:456). Fossil occurrences have been un-
common, restricted to latest Pleistocene (Wisconsinan)
of Ohio (LaRocque, 1968:456), and from two medial
Pleistocene (Illinoian) localities in Illinois (Leonard et al..
1971:6). Acroloxus coloradoensis is even less common,
currently known to exist only in a very few lakes of river
systems tributary to the Arctic Ocean or Hudson Ba\
(Clarke, 1973:263: Mozley, 1926:56), and in a remote
mountain lake in Colorado (Walker, 1925:1). Fossil oc-
currences are only two, the Sand Draw Local Fauna,
Brown County, Nebraska, and the Dixon Local Fauna,
Kingman County, Kansas (Taylor, 1960:32-40), both of
late Pliocene age (late Blancan, 2.2-3.0 MA).

Comparison of the faunas of these two Knox County
localities with nearb\' modern faunas is most instructi\e.

With the exception of the four aforementioned species,
over 90% of the mollusks listed in table 1 are currently
found living within an approximately 160 kilometers
(100 s.m.) radius in northeastern Nebraska, southeastern
South Dakota, southwestern Minnesota or northwestern
Iowa. The two trees and the fish are also found locally,
or within a similar radius. It can, therefore, be inferred
that the climate of northeast Nebraska during the late
Pliocene, immediately preceding the first glacial ad-
vance, was quite similar to, but slightly cooler than, that
of today. The presence of lakes in an area presently
lacking lakes suggests either greater annual precipitation,
or lessened evaporation due to cooler summer maximum
temperatures.

Figures 2-4 Unusual Gastropods from the late Pliocene of
northeastern Nebraska. 2 Lymnaea (Acella) haldemani. K\-
14:5. aperture hroken back about '/2 whorl; 3-4. Acroloxus colo-
radoensis. broken specimens, 3, KX-143, 4. KX-109, All lOx,

Page 56

THE NAUTILUS, Vol. 104, No. 2

LITERATURE CITED

Baker, F. C. 1928. The frt'sli water Mnllusca of Wi.scoiisiii,
Part 1. CJa.strnpoda Wiseonsin Geological and Natural His-
tory Sarve\ Bulletin 70, Part 1. 507 p

Baker, F. C. 1938. New land and freshwater Mollusca from
the upper Pliocene of Kansas and a new species of Gy-
raulus from early Pleistocene strata. Nautilus .51:126-131.

Biiinev, VV. G. 1867. Notes surquelquesespecesdemollusques
Quviatiles de I'Amerique du Nord. Journal Conchliologie
15:-427-132.

Boellsdorf, J. 1930. Fission-track ages of Pleistocene volcanic
ash deposits in the Gentral Plains, U.S.A. Isocliron/West
8.39-42.

Clarke, A. H 1973. The freshwater mollusks of the C'anadian
interior basin. Vlalacologia 13(1-2) :l-509

Henderson, J. 1930. Ancyhis coloradoensis, new name for A.
hendersuni Walker, 1925, not 1908. Nautilus 44:31.

LaRocque, A. 1968. Pleistocene Mollusca of Ohio. Ohio Di-
vision of Geological Surve\ Bulletin 62. Part 3 pp. 357-
553.

Leonard, .\. B. 1950. .■^ Varrnouthian molluscan fauna in the
Midcontinent region of the L'nited States. University of
Kansas Paleontological Contributions, Article 3, 48 p.

LeonartI, \ B , J C. F'r\e, and \V. H. Johnson 1971 lllinoian
and Kansas molluscan faunas of Illinois. Illinois State Geo-
logical Survey (^iircular 461, 24 p.

Mozley, A. 1926. Preliminary list of the Mollusca of Jasper
Park, Alberta. Nautilus 40:53-56.

Ta\lor. D. W. 1960. Late Cenozoic molluscan faunas of the
High Plains. U.S. Geological Survev Professional Paper
337, 94 p., 4 pi

N'oorhies, M. R and R. G. Goodwin 1989 Plio-Pleistocene
glacial deposits of northeastern Nebraska: new exposures
and interpretations. Nebraska Geological Societ) . no pagi-
nation.

Walker, B. 1925. New species of North American .\nclyidae
and Lancidae. University of Michigan Museum of Zoology
Occasional Paper 164, 13 p

THE NAUTILUS 104(2):57-71, 1990

Page 57

A New Molluscan Faunule from the
Caribbean Coast of Panama

Edward J. Petuch

Department of Geology
Florida Atlantic University
Boca Raton, FL 33431, USA

ABSTRACT

The Carribbean coast of Panama, particularK the area aroumi
the San Bias Archipelago, has been iound to represent part ot
a new subregion of the Caribbean Molluscan Pro\ince, antl
harbors an endemic gastropod fauna. This new faunal di\ision,
referred to here as the Blasian Subregion (for the San Bias
Archipelago), characteristically contains a large number of Pan-
amic-Caribbean cognate species pairs, and has a distinctive
Panamic appearance. Being predominantK a coralline area in
an otherwise muddy region of the Caribbean, the Blasian Subre-
gion also contains numerous taxa that are closeK related to
coral reef-dwelling species from the Bahamas and Florida. The
Blasian Subregion ends abrupth at the Golfo de Uraba, on the
Panama-Colombia l)order and, based on peripheral data, ma\
extend northward to the Costa Rica-Nicaragua border. Si.xteen
new Blasian species are described, including TurrilcUa mart-
anopsis n.sp., Chicoreus hilli n.sp., Dcrmomurcx (Trialatella)
cuna n.sp., Murexiella edivardpauli n.sp., Latirus cuna n.sp.,
Mitra {Nebularia) leonardi n.sp., Prunum leonardhilh n.sp.,
Valuta lacertina n.sp., Fahihjria crnesti n.sp., Contis brun-
ncofilaris n.sp., Conus ernesti n sp., Conus hilli n.sp , Conus
porlobeloensis n.sp.. Conns rosemanjae n.sp,, Fusiturricula
sundcrlandi n.sp., and Kncfcistia hilli n.sp., and three new
Blasian subspecies are described, including Mitrcx ruhidus pan-
amicwi n.subsp., Oliva (Strephona) relindaris ernesti n subsp,.
and Conus granarius panamicus n.subsp.

Key ivords: Caribbean; Panama; gastropods, San Bias Archi-
pelago.

INTRODUCTION

The southern Caribbean region contains one of the least
studied molluscan faunas in the Recent western Atlantic
Although originalK thought to house a typical Caribbean
tropical molluscan fauna (Valentine, 1973:356), the
coastlines of eastern Central America and northern South
America are now known to harbor geographically dis-
crete faunules, each differing from one another in species
composition (Petuch, 19SS). Two of these faunules, one
along northern Honduras and eastern Nicaragua, and
the other along northern Colombia and the Gulf of Ven-
ezuela, were found to contain numerous living archaic
genera and species complexes that pre\iousl\ were

thought to have been extinct since the late Pliocene
(Petuch, 1980, 1981, 1982). These geographically sharp-
ly-defined pockets, each with its own characteristic mol-
luscan assemblage, demonstrate that the southern Carib-
bean is not a faimistically homogeneous region but is,
instead, a biogeographical mosaic of small, distinctive
faunules.

While the gastropod faunas of coastal Honduras and
Nicaragua, and northern Colombia and the Gulf of Ven-
ezuela are now better known (Petuch, 1987, 1988), the
intervening Caribbean coasts of Costa Rica and Panama
have been, to date, poorly studied. Only a single large
detailed work has ever been published on the molluscan
systematics of this area (Olsson & McGinty , 1958). That
paper, however, concentrated on the micromollusca and
small macromollusca that were collected in beach drift
near Bocas del Toro and Colon, Panama. Nevertheless,
the authors described a number of unusual new species
(some of which are listed later in this paper) and dem-
onstrated that the Panama coast did not ha\e a typical
West Indian-type Caribbean fauna. Houbrick (1968) fur-
ther showed that several of Olsson and McGinty's new-
Panama species were also present at Portete, Costa Rica.
These range extensions indicate that the (Caribbean coasts
of Panama and Costa Rica harbor a fourth Central .Amer-
ican-northern South American faunal subregion. \ year
later, Radwin (1969) published a species list of macro-
mollusks that had been collected from dredged spoil piles
near Cxilon. By incorporating the taxa of Olsson and
McGinty, this smaller work became the first, and only,
compendium of the molluscan faima of this fourth faunal
subregion.

L'nlike the Honduran and Colombian mainlands, w hich
have large areas of mudcK coastline [i.e.. the Gull of
Uraba), the Caribbean coasts of Panama and Costa Rica
contain large areas of coral reefs and coralline algal rub-
ble bottoms. Typical of these carbonate areas are the reef
platform and coral cays of the San Bias .Archipelago and
the massive coralline algal reefs and ridges along the
Portobelo coast and at Moro Tupo (Vermeij, 1978:88-
89). While working with local fishermen who trawl off-
shore of these carbonate areas, several Panamanian mala-
cologists, in particular Mr. James Ernest of Balboa, have

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THE NAUTILUS, Vol. 104, No. 2

recently collected numerous and important new species
of macrogastropods. Since the ranges of the niicrogas-
tropods of the Caribbean are still ver\ poorly know n, the
biogeographical implications of Olsson and McGinty's
micromolhisks, as indicators of a new faunal subregion,
are too tenuous. On the other hand, the ranges of the
Caribbean macrogastropods, particularly those of the
eighteen eutropical index families (Petuch, 1988:6-7),
are much better known. In this case, the macrogastropods
collected by Mr. Ernest are excellent biogeographical
indicators, especially since the ranges of their congeners
in Honduras, Nicaragua, Colombia, and Venezuela have
recently been established (Petuch, 1987, 1988).

The new taxa described in this paper help to demar-
cate yet another biogeographical subregion of the Ca-
ribbean Molluscan Province. This new subdivision is
spatially bounded by the Honduran and Colombian- Ven-
ezuelan Subregions (Petuch, 1988; figure 42) and includes
the coasts of C^osta Rica and Panama. Since the San Bias
Archipelago of Panama is the ecological and faunistic
archetype, I here refer to this new biogeographical entity
as the "Blasian Subregion". Unlike the Honduran and
Colombian- Venezuelan Subregions, which contain nu-
merous Pliocene Caribbean relictual taxa, the Blasian
Subregion characteristically contains numerous Panam-
ic-Caribbean cognate species pairs (scnsi/ Radwin, 1969).
Of the nineteen new Blasian taxa described here, seven
represent previously-unknown cognate pairs. The other
twelve taxa include endemic Blasian members of Carib-
bean species complexes. Nine gastropod families are rep-
resented by the new species, and all of these higher taxa
can be used for provincial subdivisional analysis (Petuch,
1988:5-8). Future collecting along the Panama-Costa
Rica mainland may uncover sufficient faunistic data to
support the elevation of the Blasian Subregion to sub-
provincial status. At present, not enough information
exists concerning the total molluscan fauna and, because
of this lack, I prefer to refer to the area as a "subregion".

THE BLASIAN GASTROPOD FAUNA

As pointed out by Radwin (1969), the Blasian gastropod
fauna bears a striking resemblance to the Panamic fauna
of western Central and South America, and in particular,
the Bay of Panama. For example, unlike the faunas of
the adjoining Honduran and Colombian regions, the Bla-
sian area contains a species of the turrid genus Knefaslia
Dall, 1919 (described here), which is normally considered
a classic Panamic group. Of particular interest in the
Blasian area is the presence of the bizarre vermetid genus
Stephopoma Morch, 1860 (Olsson & McGinty, 1958;
Houbrick, 1968; Radwin, 1969). Like Knefastia. this
characteristic Panamic gastropod is found in the (Carib-
bean only within the Blasian subregion. The small, en-
crusting vermetid, Stephopoma myrakeenac OLsson and
McGinty, 1958, lives embedded within the coralline algal
ridges along Colon and the San Bias Archipelago, and at
Portete, Costa Rica, and is characteristic of the unitiue
Blasian lithothamnion community.

The new Blasian members of gastropod cognate pairs
are of particular importance in that they underscore the
faunal ties to the Panamic-Eastern Pacific areas. Some
newly discovered examples of Caribbean-Panamic cog-
nates, based on new taxa proposed in the systematic
section of this paper, include: Turritella marianopsis
n.sp. and T. mariana Dall, 1908; Dermutnurex (Triala-
tella) cuna n.sp. and D. (Trialatclla) cunniiighamae
(Berry, 1964); Murexiclla edwardpaiiH n.sp. and M.
keenae Vokes, 1970; Latirus cuna n.sp. and L. centri-
fugus (Dall, 1915); Mitra (Nebitlaria) leonardi n.sp. and
M. (Nebularia) sphoni Shask% and Campbell, 1964;
Pntnum Iconardhilli n.sp. and P. curium (Sowerby, 1833);
and Knefastia hilli and K. olivacea (Sowerby, 1833).

The Atrato Seaway, the last connection between the
Pacific and Atlantic Oceans, closed at the end of the
Pliocene (Whitmore & Stewart, 1965; Woodring, 1966;
Petuch, 1988), and had its eastern opening along what
is now the San Bias Archipelago and the Golfo de Uraba.
This area, which was the last to be exposed to the Pacific
molluscan fauna, would be expected to have the most
Panamic-appearing molluscan assemblages in the Carib-
bean. The recent discovery of whole suites of new cog-
nate gastropods living along the Blasian area supports
this hypothesis. The enclave of Panamic mollusks in the
Caribbean, however, is geographically small, ranging
from near San Juan del Norte, Nicaragua (near the Nic-
aragua-Costa Rica border) in the west to the Golfo de
Uraba in the east. The broad Honduras-Nicaragua con-
tinental shelf, which contains the Honduran Subregion,
narrows and ends at San Juan del Norte. At that point,
the muddy environment of the Nicaraguan coast shifts
to the cleaner carbonate environments of Costa Rica and
Panama. A similar situation takes place at the western
edge of the Golfo de Uraba, indicating that substrate
type is the major limiting factor in the configuration and
distribution of the southern Caribbean molluscan subre-
gions. The substrate and bathymetric preferences of some
of the new taxa are discussed under the individual de-
scriptions in the systematic section. The entire Blasian
Subregion, with its attendant faunule appears to occupy
a stretch of coastline of only slightly over 800 km.

The following is a listing of some of the macrogastro-
pods that are presentK known to be confined to the
boundaries of the Blasian Subregion. Most of these belong
to ke\' tropical biogeographical index families (as out-
lined by Petuch, 1988). Several smaller macrogastropods
that were described by Olsson and McGinty (1958) are
also listed.

Turbinidae-Liotiinae

Arenc Intleri Olsson and McGinty, 1958
Turritellidae

Turritella marianopsis Petuch, n.sp.
Vermetidae

Uteplidpoma myrakeenac Olsson and McGinty, 1958
CCerithiidae

Ceritliium carihhaeum M. Smith, 1946

E. J. Petuch, 1990

Page 59

Muricidae

*Chicoreus emihjae Petucli, 1987

Chicoretts hilli Petuch, n.sp,

Dermomurex ciina Petuch, n.sp.

Mitrexiella edwardpauli Petuch, n.sp.

Miirex rubidun panamicus Petuch, n.sp.
Fasciolariidae

Latirits cuna Petuch, n.sp.
Cohimbelhdae

Nassarina diibia Olsson and McGint\, 1958
Olividae

Oliva reticularis crncsti Petuch, n.subsp.

Olivella chiriqiiicnsis Olsson, 1956

Olivella marmosa Olsson and McGinty, 1958
Margineilidae

Gibhcrula bocasensis Olsson and McGinty, 1958

Persicula iveberi Olsson and McGinty, 1958

Prunum IconardhiUi Petuch, n.sp.
Mitridae

Mitra (Nebularia) Iconardi Petuch, n.sp.
Volutidae

Falsihjria ernesti Petuch, n.sp.

Valuta lacertina Petuch, n.sp.

Vohita Hndae Petuch, 1987
Conidae

Conns brunncofilaris Petuch, n.sp.

Conus ernesti Petuch, n.sp.

Conns granarius panamicus Petuch, n.subsp.

Conns hiUi Petucli, n.sp.

Conns portobeloensis Petuch, n.sp.

Conns rosernaryae Petuch, n.sp.
Turridae

Fnsitnrricula sunderlandi Petuch, n.sp.

Knefastia hilli Petuch, n.sp.

SYSTEMATIG SECTION

The type material of the following new species is de-
posited in the collection of the Division of Mollusks,
National Museum of Natural History, Smithsonian In-
stitution, Washington, DC,, and bears USNM numbers:

Gastropoda
Prosobranchia
Gaenogastropoda
Gerithiacea

* Note Due tu an error in my field notes, 1 iiicorreeti) gave
the type locality of Chicoreus emilyae as "off Punta Patuca,
Honduras" (Petuch, 1987:65). This erroneous type locality is
here emended to "Bocas del Toro, Panama ', the locality of the
paratype. The other paratypes that came from "off Roatau is,,
Honduras ', appear to represent another, undescribed Chico-
reus species, and not E. emilyae. Chicoreus emilyae has now
been found to be a true Blasian endemic This is probably the
"Chicoreus ftorifer" listed b> Radwin (1969:231).

Family Turritellidae

Genus Turritella Lamarck, 1799

Tnrritella marianopsis new species

(figures 1-3)

Material examined: Holotype — Length 58 mm, trawled
by commercial fishermen from 65 m depth off Portobelo,
Panama, USNM 860523; Paratypes 1-3— same locality
and depth as holotype, lengths 52, 44 and 47 mm, USNM
860524.

Description: Shell tightly coiled, very elongated, classi-
calK turritelliform; whorls with 2 large cords, with the
anterior cord being better developed and projecting far-
ther from shell than posterior cord; 2 large cords strongly
beaded, giving shell rough appearance; 2 smaller, thin,
beaded threadlike cords present between 2 large cords,
and 1 thin beaded cord present between posterior cord
and suture; shell color brownish-tan with numerous
closely-packed, thin, darker brown longitudinal flam-
mules; early whorls pale whitish-tan; beaded cords with
alternating light tan and dark brown spots, giving shell
speckled appearance; base of shell light tan with scattered
tan flammules; aperture wide, slightly rectangular in
shape.

Etymology: Named for the new species resemblance
to the Panamic Turritella mariana Dall, 1908 (. . . "look-
ing like mariana").

Discussion: Turritella marianopsis is morphologically
closest to the Panamic T. mariana Dall, 1908, especially
in shell shape, color pattern, and number of spiral cords,
but differs primarily in being more coarsely sculptured,
with larger beading and stronger, more elevated spiral
cords. Otherwise, the two species are very similar and
form an excellent example of a Panamic-Caribbean cog-
nate pair. According to local collectors, T. marianopsis
is an abundant species at depths of around 60 m, and
apparently forms solid beds off the Portobelo coast.

Muricacea
Muricidae
Chicoreus Montfort, 1810

Chicoreus hilli new species
(figures 4, 5)

Material examined: Holotype — Length 26 mm, traw led
by commercial fishermen from 65 m depth off Portobelo.
Panama, USNM 860525; Parat)pes 1, 2— lengths 24 and
26 mm, same locality and depth as holotype, Leonard
Hill collection; Paratype 3 — length 24 mm, same locality
and depth as holotype, USNM 860526.

Description: Shell small for genus, fusiform in shape,
thin and delicate; 3 well de\eloped varices per whorl;
each bod) varix ornamented with 4 spines — one large
spine on shoulder, one small spine at midbody, and 2
small spines clumped together at bod\ whorl-siphonal
canal junction; large spine on shoulder 4 times length oi
smaller spines; small, scalelike spines sometimes present

Page 60

THE NAUTILUS, Vol. 104, No. 2

between larger spines on varix; varical spines open,
cupped, ramose; inter\arital areas ornamented \\ ith one
large, elongateil knob; bodv whorl sculptured with 12-
13 thin, raised spiral cords; one or more very fine sec-
ondary threads present between cords; siphonal canal
very elongated, narrow, ornamented with 3 large, flat-
teneil spines per varix; spiral cords and threads on body
« horl and siphonal canal minutely scaled; aperture pro-
portionally large, ovate; shell color light brownish-tan,
\\ ith varices and intervarical knobs being of darker chest-
nut brown.

Etymology: Named for Mr. Leonard C. Hill of Miami,
Florida, who recognized the species as new and who
kiiulK donated the type material.

Di>icussion: Chicoreus hilli is closest to C mergtis Yokes,
1974 from Florida, the West Indian .Arc, and northern
South America, but differs in being a smaller, thinner,
more elongated shell with proportionally much larger
spines. The varices of Chicoreus mergus are very thick
and rounded, giving the shell a compact, squat appear-
ance. The varices of Chicoreus hilli, on the other hand,
are much thinner and sharper, giving the shell a more
elongated, graceful appearance. The siphonal canal of
C. hilli is also much narrower and proportionally much
longer than that of C. mergus. The shoulder spine of C.
hilli is also proportionally at least twice as long as the
shoulder spine of C. mergus.

Chicoreus hilli is also similar to Chicoreus bullisi Yokes,
1974, from off Nicaragua, but differs in being a much
smaller, much more delicate shell with smaller and less-
developed varical spines. The varices of C. bullisi, like
those of C. mergus, are also much thicker, wider, and
more rounded than those of C hilli. The new species is
the smallest known Chicoreus in the western Atlantic,
and appears to be restricted to the coralline algal and
carbonate rubble areas off Portobelo and the San Bias
Archipelago.

Dermomurex Monterosato, 1890
Tridatella Berry, 1964

Dermomurex {Trialatella) cuna new species
(figures 9, 10)

Material examined: Holotype — Length 14 mm, trawled
by commercial hshermen from 65 m depth off Portobelo,
Panama, USNM 860527; Paratype 1— length 13 mm,
same locality and depth as holotype, Leonard Hill col-
lection, Miami, Florida.

Description: Shell elongated, fusiform, thin and fragile;
early whorls with 6 small thin varices per whorl; body
whorl and penultimate whorl with 3 large, thin, winglike
varices per whorl; bodv whorl ornamented with 6 low
flattened cords with cord along shoulder being strongest
and best developed; cords extend onto winglike varices,
producing slightly scalloped edges; cords of intervarical
areas ornamented with small, evenly-spaced nodules; si-
phonal canal elongated, well developed, slightly re-
curved; aperture proprotionally large, oval in shape; en-
tire shell covered with thick, cream-white, pebbled
intritacalx; surface of intritacalx of varices finely striate.

Etymology: Named for the Cuna Indians of the San
Bias Archipelago.

Discussion: Dermomurex (Trialatella) cuna is the fifth-
known member of its three-winged subgenus to be found
in the western Atlantic. The other species include D.
abyssicola (Crosse, 1865) from Guadeloupe, French An-
tilles, D. glicksteini Petuch, 1987 from southeastern Flor-
ida, D. kaicherae Petuch, 1987 from Yenezuela, and D.
oxum Petuch, 1979 from the Abrolhos Archipelago, Bra-
zil. Of the Atlantic species, D. cuna is closest to D. kaich-
erae, but differs in being a more broad-shouldered shell
with a proportionally lower spire, and in being a smooth-
er, less sculptured shell lacking the broad, thick inter-
varical cords and knobs of D. kaicherae (Petuch, 1987:
plate 24, figures 17, 18). Of the known Trialatella species,
D. cuna is closest to the Panamic D. cunninghamae
(Berry, 1964), the type of the subgenus, and the two form
an obvious cognate pair. The new Caribbean species
differs from its Panamic cognate in being a more elon-
gated, slender shell with a proportionally higher spire
and less developed winged varices. The form and number
of the body whorl cords and the structure of the intri-
tacalx of the two species, however, are very similar.

Yokes (1975: plate 4, figures 3a, b) illustrated a smaller
specimen of D. cuna from "Holandes Cav, off ("ape San
Bias, Panama, 22 fathoms l)ut referred it to the Lesser
Antilles species D. abyssicola. She later reillustrated the
same specimen (Yokes, 1985: figures 13a, b). but this time
referred the Panamanian shell to the Brazilian D. oxun^.
This now well-known specimen of D. cuna, however, is
a juvenile (with 6 varices) of only 9 mm length, and does
not exhibit the adult proportions. Fully mature, three-
winged specimens of D. cuna (approximately 13 mm)
and D. oxuni (holotvpe 12.5 mm) are quite different,
with D. oxum being a much broader, stockier shell with
wider bodv whorl cords and elongated intervarical knobs.
.Although similar to, and often confused with D. abys-

Figures 1-22. New gastropods from the Caribbean coast of Panama 1, 2. Turrilrtla marianopsis new species, liolotype, length
58 mm. L'SN'M 860523. 3. Turriletla marianopsis new species, paratype, length 52 mm. I .SNM 860524. t. 5. Chicarcn.s hilli new
species, holotype, length 26 mm. I S.WI 860525 6, 7. Murcxiclla cdnardpauli new species, holotvpe. I'SNM 860529 8. \tnrex
rubidus panamicus new subspecies, holotype, length 26 mm, I SNM 860528 9, 10. Dcrnionuircx (Trialatella) cuna neu species,
holotype, length 14 mm, USNM 860527. 11. Valuta virescens Lightfoot. 1786, 43 min specimen from Cartagena. Colombia, tor

E. J. Petuch, 1990

Page 61

comparison with Valuta lacertina. 12. 13. Latirus cuna new species, holotype, length 46 mm, I SNM 860531. 14, 15. Mitra
[Nebularia] leonardi new species, holotype, length 22 mm, USNM 860533. 16. Valuta lacertina new species, paratype, length 29
mm, IISNM 860538. 17, 18. Prunum leonardhilli new species, holotype, length 19 mm, I'SNM 860536. 19, 20. Oliva (Strephona)
reticularis ernesti new species, holotype, length 38 mm, USNM 860535. 21, 22. Valuta lacertina new species, holotvpe, length 31
mm, USNM 860537.

Page 62

THE NAUTILUS, Vol. 104, No. 2

sicola, D. cuna is a larger, broader shell with a higher,
more obvioiisK' stepped spire. The siphonal canals of botli
D. oxum and D. ahyssicola are neither as elongated nor
as well developed as that of D. cuna. and are not re-
curved.

In the fossil record, D. cuna is most similar to D.
antecessor Vokes, 1975 from the early Pleistocene of
Costa Rica (Moin Formation) and southern Florida (Ber-
mont Formation) This possible Pleistocene ancestor,
however, differs from the Recent Blasian species in being
a more elongated species with less developed varices and
coarser corded body whorl sculpture.

Murcx Linnaeus, 1758

Murex rubidus panainictts new subspecies
(figure 8)

Material examined: Holotype — Length 26 mm, trawled
by commercial fishermen from 50 m depth off Portobelo,
Panama, I'SNM 860528; Paratype 1— length 27 mm,
same locality and depth as holotype, Leonard Hill col-
lection, Miami, Florida.

Description: Shell small for genus, with fusiform body;
spire high, elevated; body whorl and varices rounded; 3
large, thick varices per whorl; 2-3 narrow, elongated
knobs in intervarical areas; body whorl, intervarical knobs,
and varices ornamented with 12-14 large, raised spiral
cords; thin spiral threads often present between spiral
cords; siphonal canal extremely long and narrow, equal
to length of shell body; base of siphonal canal ornamented
with 2 small spines; aperture small, rounded; peristome
ornamented v\ ith numerous large white teeth; shell color
bright orange with 2 darker orange-tan bands, one around
shoulder and one around body whorl-siphonal canal junc-
tion; posterior half of siphonal canal brown; anterior half
of siphonal canal pale orange-white.

Etymology: Named for Panama, the country of the type
locality.

Discussion: Murex rubidus Baker, 1897 is now known
to have a split distribution within the Caribbean region,
with the nominate subspecies, M. rubidus rubidus. being
found along the southeastern and western coasts of Flor-
ida and the northern Bahamas (Radwin and D'Attilio,
1976:71), and with a small, isolated population, M. rubi-
dus panamicus, being found along Caribbean Panama.
Both populations may be relicts of a once wide-ranging
Pleistocene species that has become biogeographically
bisected and spatially reduced since the late Pleistocene.
Several other Blasian species also share close morpholog-
ical similarities with Bahamian gastropods. Included are
the Blasian Chicoreus emihjae Petuch, 1987 and the
Bahamian-Floridian C. florifer Reeve, 1846 and the Bla-
sian Conus hilli n..>-p and the Bahamian Conus jucundus
Sowerby, 1887 (= C. abbotti Clench, 1942).

Murex rulndus panamicus differs from the nominate
subspecies in being a much more slender, more fusiform
shell with a much higher, more protracted spire. The
body whorl of A/, rubidus rubidus is rounded and glo-

bose, while the body whorl of M. rubidus panamicus is
narrower and elongated.

Murexiella Clench and Farfante, 1945

Murexiella edwardpauli new species
(figures 6, 7)

Material examined: Holotype — Length 15 mm, trawled
by commercial fishermen from 50 m depth off Portobelo,
Panama, USNM 860529; Paratype 1— length 15 mm,
same locality and depth as holotype, USNM 860530.

Description: Shell small for genus, thin, delicate, with
globose, inflated body; 6 varices per whorl, varices thin,
with 6 large, recurved spines; intervarical areas orna-
mented with 6 large spiral cords; intervarical cords and
varices minutely squamose; siphonal canal proportion-
ally very elongated, ornamented with 3 large, flattened
spines per siphonal varix; shell consistentK pinkish-tan
colored with 2 darker tan bands, one around shoulder
and one around midbody; shoulder of body whorl slightly
angled; aperture proportionally large, oval in shape.

Etymology: Named for Mr. Edward D. Paul of Miami.
Florida.

Discussion: Murexiella edwardpauli is closest to Mu-
rexiella macgintyi (Smith, 1938) from Florida and the
Bahamas, but differs in being a much smaller, more
delicate species with a much more globose body whorl,
less angled shoulder, and proportionally longer and nar-
rower siphonal canal. Murexiella edivardpauli is also
similar to M. leonardhilli Petuch, 1987 from Brazil, but
differs in being a much smaller shell with thinner, less
crassate varices. In the eastern Pacific, M. edwardpauli
is very similar to M. keenae Vokes, 1970, but differs in
being a smaller shell with a proportionalK longer si-
phonal canal. Based on shell morphology, M. keenae and
M. edivardpauli can be seen to be ver\' closeK' related
and represent Panamic-Caribbean cognates.

Fasciolariidae
Peristerniinae
Latirus Montfort, 1810

Lalirus cuna new species
(figures 12, 13)

Material examined: Holotype — Length 46 mm, traw led
by commercial fishermen from 60 m depth off Portobelo,
Panama, USNM 860531; Paratype 1— length 42 mm,
same locality and depth as holotype, USNM 860532;
Paratope 2 — length 45 mm, same localits and depth as
holotype, collection of Leonard Hill, Miami, Florida.

Description: Shell elongately fusiform, w ith high, sca-
lariform spire and narrow protracted siphonal canal;
shoulder sharply angled, with rounded, spikelike knobs;
whorls with 8 narrow, raised axial ribs per whorl; axial
ribs (>\erlaid with 5 large, thick spiral cords; 2 spiral
ct)rds at shoulder largest and best developed, projecting
farthest from shell body; areas between large cords or-

E. J. Petuch, 1990

Page 63

namented with numerous very fine cords and spiral
threads; siphonal canal ornamented with 4 large spiral
cords; areas between large siphonal cords ornamented
with numerous fine cords and threads; interior of aper-
ture with 10-12 large, beaded cords; edge of lip fineK
crenulated, with crenulations corresponding to fine spiral
cords and threads on shell surface; narrow umbilicus
present; shell color bright orange-tan; large cords of body
whorl, spire, and siphonal canal white; interior of ap-
erture orange.

Etymology: Named for the Cuna Indians of the San
Bias Islands,

Discussion: Latiriis cuna somewhat resembles the wide-
spread Caribbean L. cariniferiis Lamarck, 1822, but dif-
fers in being a more slender, elongated shell with a nar-
rower, more protracted siponal canal, and in having a
more sharpK -angled shoulder with proportionally larger
and sharper shoulder knobs. The new Blasian species is
also similar to the Panamic L. ccntrifugus (Dall, 1915),
but differs in being a more slender, elongated shell with
a proportionally longer siphonal canal. Otherwise, both
L. centriftigus and L. cuna share the same type of sharp-
ly-angled shoulder, large shoulder knobs, and strongly
projecting shoulder cords. I feel it is safe to assume that
L. cuna and L. ccntrifugus form a cognate species pair.

Volutacea

Mitridae

Mitra Lamarck, 1798

Nebularia Swainson, 1840

Mitra {Nebularia) leonardi new species
(figures 14, 15)

Material examined: Holotype — Length 22 mm, trawled
by commercial fishermen from 60 m depth off Portobelo,
Panama, USNM 860533; Paratype 1— length 20 mm,
same locality and depth as holotype, USNM 860534.

Description: Shell narrow and elongated, fusiform; spire
high, protracted, scalariform; suture indented, producing
narrow shoulder area and stepped spire whorls; body
whorl ornamented with 12 large, thick spiral cords; col-
umella with 4 plications, with posteriormost plications
being largest; shell color white, heavily overlaid with
wide, reddish brown vertical flammules; reddish-brown
flammules often coalesce into large, longitudinal patches;
some specimens (holotype) with thin white band around
midbody; aperture thin, narrow, roughly one-half length
of shell.

Etymology: Named for Mr. Leonard C. Hill of Miami,
Florida who kindly donated the type material.

Discussion: In the Caribbean, Mitra leonardi is closest
to M. semiferrtiginea Reeve, 1845, from the Bahamas,
but differs in being a smaller, much narrower shell with
a proportionally larger aperture. The two species also
differ in color; with M. semiferruginea being colored
bright yellow with dark, blackish-brown flammules and
with M. leonardi being white with reddish-brown flam-

mules. In the eastern Pacific, M. leonardi is closest to M.
sphoni Shasky and Campbell, 1964, especially in size and
color, but differs in having a more scalariform, stepped
spire. Mitra sphoni and M. leonardi. together, are another
example of a Panamic-Caribbean cognate species pair.

Olividae

Oliva Bruguiere, 1789

Strephona Morch, 1852

Oliva (Strephona) reticularis ernesti new subspecies

(figures 19, 20)

Material examined: Holotype — Length 38 mm, trawled
from 40 m depth on silty sand bottom off Portobelo,
Panama, USNM 860535; Paratypes 1-3— lengths 37-41
mm, same locality and depth as holotype, Petuch col-
lection.

Description: Shell average size for subgenus, cylindri-
cal, with only slightly rounded shoulder; spire low; body
whorl colored yellowish-tan, overlaid with dense, close-
packed pattern of small, dark brown triangles and zig-
zags; 2 wide bands of darker brown triangles present
around bod>' whorl, one around anterior one-third and
one around area just posterior of midbody line; sutural
area marked with large, evenly-spaced yellow patches
and numerous fine black hairlines; spire whorls glazed-
over with dark purple-brown enamel; aperture and col-
umellar area white; columella with 15-20 thin plicae;
fasciole yellow-tan marked with 2 rows of large dark
brown checkers; protoconch proportionally small, col-
ored dark purple-brown.

Etymology: Named for Mr. James Ernest of Balboa,
Panama, who collected the type lot.

Discussion: Oliva reticularis ernesti from the Blasian
area differs from O. reticularis reticularis Lamarck, 1810,
from the Bahamas and West Indian Arc, in being a more
straight-sided, cylindrical shell with a much lower spire.
The new subspecies is also a darker-colored shell with a
finer and denser pattern of triangle markings. Oliva re-
ticularis ernesti occurs with, and has often been confused
with, Oliva hewleiji Marrat, 1871. That species, however,
is a much larger shell (av. 55 mm) with a proportionateK'
higher spire and larger protoconch. Oliva bewleyi has a
much more diffuse color pattern, with the triangle mark-
ings and zigzags having a "smeared" look. The triangle
markings of O. reticularis ernesti. on the other hand,
are consistently clear and distinct. Although O. bewleyi
is now known to range from Panama to Santa Marta,
Colombia (Petuch & Sargent, 1986:126), O. reticularis
ernesti appears to be restricted to the Blasian area.

Marginellidae

Prunum Hermannsen, 1852

Prunum leonardhilli new species

(figures 17, 18)

Material examined: Holot\ pe — Length 19 mm, trawled
from 60 m depth h\ commercial fishermen, off Portobelo,

Page 64

THE NAUTILUS, Vol. 104, No. 2

Panama, USNM 860536. Paratypes 1, 2— lengths 18 mm
and 19 mm, same locality and depth as holotype, Leon-
ard Hill c'ollet'lioM.

Description: Shell elongated, ovate, somewhat inflated;
base of shell flattened anteriorly, bordered by thickened
parietal callus that connects with thickened outer lip
around anterior end; margins of shell thickened; spire
relatively low; columella with 4 very large plications that
extend beyond aperture region onto shell base; aperture
narrow, slightly wider at anterior end; shell pale bluish-
gray color with 2 darker gray bands; thickened lip and
basal callus white; junction of body whorl and lip marked
by thin \ ellow line; body whorl-lip junction area suffused
with pale yellow color; interior of aperture bright orange-
brown; protoconch and early whorls pale orange-tan.

Elymology: Named for Mr. Leonard C. Hill of Miami,
Florida, who kindly donated the holotype.

Discussion: Prttruim Iconardliilli is very similar to P.
curtum (Sowerby, 1832) from the coasts of Ecuador and
Peru, as both species share the same shell shape, shell
size, and form of the columellar plications. Pritnum cur-
tum. however, is a yellow shell with a pale orange outer
lip, while P. leonardhilli is basically a blue-gray shell
with a white outer lip. Regardless of color, the two species
appear to be cognates. In the Caribbean P. leonardhilli
is closest to P. prunum (Gmelin, 1791), which is abundant
and widespread along the coasts of Colombia and Ven-
ezuela. The new Panamanian species differs from the
common P. prunum, however, in being a smaller, more
globose, and less elongated shell, with much larger col-
umellar plications. The columellar plications of P. pru-
num do not extend as far onto the shell base as do those
of P. leonardhilli. The two species also appear to be
ecologically exclusive, with P. prunum preferring the
organic-rich coastal muds and P. leonardhilli preferring
fine particulate carbonate bottoms in offshore areas.
Prunum leonardhilli is sympatric with another Blasian
marginellid endemic, Persicula weheri Olsson and
McGinty, 1958.

Volutidae
Volutinae
Valuta Linnaeus, 1758

Valuta lacerlina new species
(figures 16, 21, 22)

Material examined: Holotype — Length 31 mm, trawled
by commercial fishermen from 100 m depth off Porto-
belo, Panama. USNM 860537; Paratype 1— length 29
mm, same depth and locality as holotype, USNM 860538;

Paratype 2 — length 30 mm, same depth and locality as
holotype, Leonard Hill collection.

Description: Shell very small for genus, averaging only
30 mm in length; shell outline broadly fusiform, tapering
toward anterior end; spire elevated; shoulder rounded,
ornamented with 10-12 low, riblike knobs; body whorl
ornamented with 20-24 horizontally-arranged, deeply
incised spiral sulci and numerous thin longitudinal plicae;
sulci and plicae intersect to produce strong cancellate
sculpture pattern; intersection of pair of sulci and plicae
producing large, raised bead, giving entire surface of
body whorl pebbly appearance; subsutural area orna-
mented with 6 large spiral cords; shell color yellowish-
tan overlaid with numerous minute brown dots and 3
bands of large light brown rectangular patches, one along
suture, one below shoulder, and one around anterior end;
protoconch proportionally large, composed of 2 whorls,
flattened and somewhat discoidal; protoconch asymmet-
rical in form, with first whorl projecting dorsally out of
alignment with second whorl; protoconch light brown in
color; aperture wide, yellow to pale orange in interior;
columella with 10 large, thin, smooth plications; thin,
small, secondary plications sometimes present between
anteriormost primary plications; outer lip of adults thick-
ened, marked with 10-12 small brown spots; operculum
unknown.

Etymology: "Little lizard", in reference to the new
species' beaded appearance, which resembles lizard skin.

Discussion: Valuta lacertina is the smallest-known Va-
luta s.s. and is also the deepest-dwelling, having been
trawled from 100 m depth. All other Valuta s.s., and
members of the closely-related Falsilyria Pilsbry and
Olsson, 1954 species complex, prefer depths of 30 to 50
m and some are often collected by SCL'BA diving (such
as Falsilyria .■iundcrlandi Petuch, 1987 from 10 m depth
off Utila Island, Honduras). At Cartagena, Colombia, the
closely-related Valuta virescens Lightfoot, 1786 is found
in shallow subtidal depths and frequently is collected as
beach specimens.

Valuta lacertina is most similar to the other Blasian
endemic volute, V. lindae Petuch, 1987 (figure 23), but
differs in being a smaller, more heavily scuptured shell
with a more rounded shoulder. The sculpture pattern of
the two species also differs, with V. lacertina having a
pebbly, beaded surface texture and with V. lindae having
stronger longitudinal plicae that give the shell a wrinkled
look. The shoulder knobs of V. lacertina are weak and
rounded, while those of \'. lindae are strong, angled, and
sharpl) pointed. Valuta lindae is also a more brightly
colored shell, being an intense yellow or yellow-orange
and having large, dark brown spots in rows around the
bodv whorl. Valuta lacertina, on the other hand, is a

Figures 2:i-il. \pu Volutes (Xoliilidae). Cones (Conidae). and Turrids (Turridae) from the C:aribbean coast of Panama 23.
Voliila lindae Petiich, 1987, 46 mm lioiotypc from Bocas del Toro, Panama, for comparison with Vohita lacertina. 21, 2,'j. Falsilyria
erne.sti new species, holoU pc |pni;lli ."^4 mm, USNM 860539. 26, 27. Conus grariarius panaminis new subspecies, hnioh |>c l.-tigth

E. J. Petuch, 1990

Page 65

24 mm, IISNM 860543, 28. 29. Conus crnesti new species, liolotype, length 29 mm, USNM 860542, 30, 31. Contts brunneofxlaris
new species, liolotype, length 14 mm, LISNM 860541, 32, 33. Conus poriobeloensis new species, hulutype, length 31 mm. USNM
860545, 34, 35. Conus rosemaryae new species, holotype, length 25 mm, L'SNM 860546. 36, 37. Conus hilli new species, hololype,
length 21 mm, USNM 860544. 38, 39. Knefastia hilli new species, holotype, length 50 mm. I'SNM 860548. 40. 41. Fusiturrirula
sunderlandi new species, holotype, length 33 mm, USNM 860547,

Page 66

THE NAUTILUS, Vol. 104, No. 2

drab little shell, being a pale tan or yellowish-tan and
lacks the large, scattered brown spots seen on V. lindac.
Both species, however, have the same fine-dotted pattern
that covers the entire shell, although the dots of V. lindae
are proportionally larger and darker. The protoconchs
of the two species also differ significantly, with that of
V". lindae being inflated and cylindrical in form, while
that of V. lacertina is flattened and asymmetrical. Balhy-
metrically, the two species also differ, with V. lacertina
living at depths of 100 m or deeper and with V. lindae
preferring much shallower areas of 20 to 50 m depth.

Valuta lacertina is also similar to the well known V.
virescens (figure 11), which ranges from off Nicaragua
to Santa Marta, Colombia, and the two species appear
to represent a pair of bathymetric siblings. As in V.
lindae, V. virescens prefers shallower depths, ranging
from 5 to 35 m. The substrate preferences of these three
closely-knit species also appear to differ, with V. lacer-
tina and V. lindae preferring coralline algal rubble and
carbonate bottoms and with V. virescens preferring
muddy, organic-rich bottoms. Valuta virescens from the
organic detrital and reducing substrates within the Golfo
de Uraba, on the Panama-Colombia border, are stained
black from reduced iron compounds and are often en-
crusted with iron sulfide Valuta lindac and \'. lacertina.
from the cleaner carbonate substrates of the Blasian area,
are usually shiny and uncoated by iron compounds.

Morphologically, V. virescens differs from V. lacertina
in being a larger shell with a smooth shell sculpture that
lacks the pebbly beading. The basic shell coloring also
differs between the two species, with V. virescens being
a characteristic green or greenish-gray while V. lacertina
is a pale yellow-tan. The protoconch of V. virescens is
proportionally smaller than that of V. lacertina, being
narrow and cylindrical in form. The protoconch of V.
lacertina is large for such a small shell, and is flattened
and almost discoidal in form. Interestingly enough, al-
though V. virescens is the largest species of the Pana-
manian-Colombian Valuta species complex, it has a pro-
portionally much smaller protoconch than those of its
diminutive relatives, V. lindae and V. lacertina.

Falsilyria and Pilsbry and Olsson, 1954

Falsilyria ernesti new species
(figures 24, 25)

Material examined: Holotype — Length 54 mm, trawled
by commercial fishermen from 65 m depth off Portobelo,
Panama, USNM 860539; Paratype 1— length 55 mm,
same locality and depth as holotype, USNM 860540;
Paratype 2 — length 54 mm, same locality and depth as
holotype, Leonard Hill collection, Miami, Florida.

De.scription: Shell narrow, elongated, fusiform, thick
and heavy; spire elevated, protracted; spire whorls slight-
ly convex in outline; whorls ornamented with 8-10 large,
rounded, axial plications; large plications overlaid with
numerous thin, riblike plications; shoulder angled, bor-
dered by single large spiral cord; subsutural areas sculp-
tured with 3 large spiral cords; subsutural spiral cords

intersect with thin axial riblets to produce beaded texture
on shoulder and spire; bod\ whorl shiny, polished; an-
terior end sculptured with 5-6 large spiral Cf)rds; colu-
mella slightly arcuate, with 11-12 thin, smooth plica-
tions; outer lip of adults thickened, projecting
posteriorward; protoconch proportionally large, round-
ed, domelike; shell color pale salmon-yellow with 2 wide
bands of brown and pale purple checkers and spots, one
around midbody and one around anterior end; midbody
band overlaid with 4-6 brown spiral hairlines and nu-
merous tiny brown vertical flammules; anterior band
similarly marked with 5 brown hairlines and tiny vertical
flammules; salmon-yellow areas between wide colored
bands completely overlaid with closely-packed, tiny or-
ange-brown speckles; protoconch light tan; columella and
interior of aperture pale salmon; edge of lip yellowish-
white, marked with evenly-spaced dark brown spots.

Etymology: Named for Mr. James Ernest of Balboa,
Panama, who collected the type lot.

Discussion: Of the Fasilyria species complex, F. ernesti
is the southernmost known member, and its discovery
came as a surprise to me. Previously (Petuch, 1987:62),
I had stated that the genus was restricted to the coasts
of Honduras and northern Nicaragua. The new Blasian
species, therefore, represents a considerable range ex-
tension for the complex. Of the eight known Falsilyria
species, F. ernesti is most similar to F. demarcoi (Olsson,
1965) from Honduras, but differs in being a much small-
er, more slender and elongated shell, with a much more
sharply-angled shoulder. The Honduran F. demarcai is
also a much more brightly colored shell, having a deep
orange base tone. The Blasian F. ernesti, on the other
hand, is a less colorful shell, having a base tone of pale
salmon-yellow. In shape and in having a small adult size,
F. ernesti is also similar to F. hara.seivychi Petuch, 1987,
from off Roatan Island. The new species differs from F.
hamseioychi. however, in having a salmon-\ellow base
color instead of white, and in lacking the wine-red flam-
mules and black and white checkered bands of F. harase-
wychi. The Roatan species has distinctive, characteristic
beaded columellar plications, while those of F. ernesti
are smooth.

Conacea
Conidae
Canus Linnaeus, 1758

Conus brunneofilaris new species
(figures 30, 31)

IVIaterial examined: Holotype — Length 14 mm, trawled
bv commercial fishermen from 65 m depth off Portobelo,
Panama, IISNM 860541.

Description: Shell small, elongately conical, thin, fra-
gile; shoulder sharpK angled, carinated; carina faintly
undulating; spire moderately elevated, with stepped
whorls; body whorl shiny and polished; anterior tip en-
circled with 6 small spiral cords; aperture narrow, slightly
w idcr at anterior end; protoconch proportionalK large.

E. J. Petuch, 1990

Page 67

mammillate; shell color bright golden-tan with wide
niidbod) band of large white patches and dark brown
flammules; anterior tip marked with large white flam-
mules; golden-tan and white base color overlaid with 21
extremely fine, hairlike, dark brown spiral lines; shoulder
and spire white with large, evenly-spaced, dark brown
flammules; spire flammules extend over edge of shoulder
carina onto body whorl; interior of aperture white; pro-
toconch and early whorls bright yellow.

Etymology: "Brown threaded", in reference to the
prominent, evenly-spaced, thin brown lines that encircle
the body whorl.

Discussion: Conns bninneofilaris. with its distinct brown
spiral lines, resembles no other known Caribbean or Pan-
amic cone shell. In shape and size, this unusual new
species is most similar to C. magnottei Petuch, 1987 from
Roatan Island, Honduras, but differs in having a bright
golden-tan base color instead of the pink and purple color
ot C. magnottei, and in having the overlay color pattern
of brown lines, which is lacking in the Honduran species.
The spire flammules of C. magnottei are also larger and
more irregular than those of C. bninneofilaris and do
not extend onto the body whorl.

Coj}tis ernesti new species

(figures 28, 29)

IMaterial examined: Holotype — Length 29 mm, trawled
by commercial fishermen form 65 m depth off Portobelo,
Panama, USNM 860542; Paratype 1— length 31 mm,
same locality and depth as holotype, Kevan Sunderland
collection.

Description: Shell slender, tapering rapidly toward an-
terior tip; shoulder wide, sharply angled; spire high, el-
evated, scalariform; shell smooth, polished, with deeply-
impressed spiral sulci around anterior end; aperture
straight, narrow; shell color white with 12-20 rows of
small brown dots and dashes; rows of dots often aligned
to form large brown vertical flammule; dotted pattern
overlaid with variable amounts of amorphous lighter
brown patches; clear band, with only one or two rows
of dots, present around midbody; some specimens (ho-
lotype) with brown patches coalescing into 2 broad bands,
one above, and one below, midbody; anterior tip of shell
white; spire whorls white with numerous, evenly-spaced
crescent-shaped flammules; early whorls brown; interior
of aperture white.

Etymology: Named for Mr. James Ernest of Balboa,
Panama, who collected the holotype.

Discussion: Conus ernesti is most similar to Conns cin-
gulatus Lamarck, 1810 from the Caribbean coast of Co-
lombia, but differs in being a smaller, lighter colored
shell with a much higher, scalariform spire. The lower-
spired Conus cingulattis is a rough-textured shell, with
the body whorl being heavily sculptured with incised
sulci and raised spiral threads. Conns ernesti, on the
other hand, is a smooth, almost polished shell, with in-

cised sulci onlv on the anterior end. The dark purple-
brown C. cingnlatus has a purple aperture, whereas the
white and light brown C. ernesti has a white aperture.
The new species is also similar to C. garciai daMotta,
1982 from the Caribbean coast of Honduras, but differs
in being a nuich smaller shell with rows of brown dots.
Like C. cingnlatus, C. garciai is also a rough-textured
shell, heavily ornamented with raised threads, and differs
greatly from the smooth C. ernesti. Together, C. garciai,
C. ernesti, and C. cingnlatus form an interesting species
complex, with each being restricted to a separate mol-
luscan assemblage.

Conns granarins partamicus new subspecies
(figures 26, 27)

Material examined: Holotype — Length 24 mm, trau led
by commercial fishermen from 40 m depth off Portobelo,
Panama, USNM 860543; Paratype 1— length 28 mm,
same locality and depth as holotype, Leonard Hill col-
lection.

Description: Shell subpyriform, tapering abruptK to-
ward anterior end; shoulder sharply angled, subcarinat-
ed; spire very high, elevated, protracted; shoulder pe-
riphery and spire whorls heavily ornamented with
numerous large, rounded beads, producing distinctly co-
ronated spire; body whorl shiny, ornamented with IS-
IS evenly-spaced rows of tiny pustules; shoulder and
subsutural area flattened, producing pronounced stepped
spire; shell color pale lilac, often overlaid with large,
vertically-oriented, light tan patches; interior of aperture
violet.

Etymology: Named for Panama, country of the type
locality.

Discussion: Conus granarins panamicus may represent
an isolated population of the wide-ranging C. granarins
granarins, which ranges from northern Colombia into
the Gulf of Venezuela. The new subspecies differs from
the nominate subspecies in being a smaller, stumpier,
more biconically-shaped shell with a proportionally higher
and more scalariform spire. Conus granarins panamicus
also lacks the spiral rows of dots that characterize the
color pattern of C. granarins granarins, and is a much
paler, less colorful shell. Some specimens of C. granarins
panamicus are uniformly pale lilac (like the holotype),
while others have large tan patches. Although the nom-
inate subspecies appears to prefer muddy, siliciclastic
sediment bottoms with large amounts of organic matter,
C. granarins panamicus prefers coralline rubble and
carbonate sand bottoms.

It is conceivable that C. granarins panamicus may, in
fact, be a full species, closely related to, but distinct from,
C. granarins granarins. The new taxon may be part of
a Honduras-Panama-Colombia species complex, much
as in the case of Conns garciai-ernesti-cingulatns. This
species complex, then, would comprise the Honduran C.
harlandi Petuch, 1987, the Panamanian C. panamicus.

Page 68

THE NAUTILUS, Vol. 104, No. 2

and the Colombian C. granarius, with each being part
of a localized, eiideiiiic fauniile.

Coriua liilli new species
(figures 36, 37)

Material examined: Ilolotype— Length 21 mm, trawled
b\ commercial fishermen from 26 mm depth off Por-
lobelo, Panama, USNM 860544.

Description: Shell stocky, broad across shoulder; spire
low, flattened; shoulder sharpK -angled, subcarinated;
shoulder and spire whorls ob.soletely coronated, with low,
evenly-spaced undulations along periphery; body whorl
very smooth, polished, shiny; anterior tip with 10 small,
slightK raised spiral cords; shell color deep purple-blue
w ith blotch) , light blue band around midbod> ; light blue
midbody band marked with 4 rows of tiny, closely-spaced
reddish-brown dots; spire whorls white with evenly-
spaced, large dark brown cre.scent-shaped flammules;
protoconch mammillate, protracted, light orange in col-
or; aperture narrow, purple within.

Etymology:

Florida.

Named for Mr. Leonard C. Hill of Miami,

Discussion: Conus hilli is most similar to, and appar-
ently is a close relative of, Conus kulkulcan Petuch, 1980
from the Bay Islands of Honduras. The new species dif-
fers from C. kulkulcan, however, in having a lower,
flatter spire, and in having a squatter, less elongated
shape. The spire whorls and shoulder of C. kulkulcan
are marked with numerous fine, dark brown hairlines.
but these are absent on C. hilli. Conus kulkulcan is also
a textured shell, having spiral rows of tiny pustules around
the body whorl. Conus hilli, on the other hand, is an
unte.xtured shell, having a highly polished, shiny body
whorl. As in the case of the last two new cones in this
paper, Conus hilli forms an interesting species trio with
closely- related Honduran and Colombian species. This
complex, then, includes C. kulkulcan from Honduras, C.
hilli from Panama, and C. colomlrianus Petuch, 1987
from northern Colombia. Other related species in this
close-knit Caribbean complex include C. jucundus Sow-
erby, 1887 (= C. abbotti Clench, 1942) and C. inconstans
E. A. Smith, 1877 from the Bahamas, C. arangoi Sarasua,
1977 from Cuba, C^ay Sal, and Turks and Caicos, C.
cardinalis Hwass, 1792 and C. cidaris Kiener, 1845 from
Hispaniola and the West Indian Arc, C. mayaguensis
Nowell-Usticke, 1968 from the Dominican Republic and
Puerto Rico, C. harasewychi Petuch, 1987 from Palm
Beach, Florida, and possibly C. abrolhosensis Petuch,
1987 from the Abrolhos Archipelago of Brazil.

Conus portobeloensis new species
(figures 32, 33)

Material examined: Holotype — Length 31 mm, Irawled
by commercial fishermen from 30 m depth off Portobclo,
Panama, USNM 860545.

Description: Shell elongate, subpyriform, with low spire;
earliest, postnuclear spire whorls protracted, becoming
flattened during ontogeny; shoulder sharpK angled, edged
with small but distinct carina that projects be>ond shoul-
der margin; body whorl smooth and shiny, with 20 large,
raised cords around anterior quarter; spire whorls smooth;
shell color white, marked with intermittent longitudinal
flammules of pale orange-tan; longitudinal flanmniles, in
turn, overlaid with scattered darker tan dots and dashes;
anterior end of body whorl pale \ellow-orange; spire
white, with scattered amorphous flammules of dark or-
ange-tan; midbody marked with clear white band; in-
terior of aperture white; protoconch and early whorls
dark orange; periostracum thin, tan, silky in texture.

Etymology: Named for the city of Portobelo, off of
which the holotype was collected.

Discussion: At first glance, Conus portobeloensis ap-
pears to be related to the C. garciai-ernesti-cingulatus
species complex, particularly in color pattern. Based upon
the presence of a shoulder carina and a subp\ rif orm body
form, however, C. portobeloensis appears to be more
closely related to C. commodus A. Adams, 1854 (reil-
lustrated by Petuch, 1987: plate 10, figures 18, 19) from
off Roatan Island, Honduras, and may be the Panama-
nian analogue. Conus portobeloensis differs from the
Honduran species in being a larger, more elongated shell
and in having a color pattern of orange-tan flammules
and dots. The new Panamian species is also similar to C.
paraguana Petuch, 1987 from the Gulf of Venezuela, as
both species have an orangish dashed color pattern and
both have a clear white midbody band. Conus porto-
beloensis differs from C. paraguana. however, in being
a much larger, broader species with a wider and more
sharply angled shoulder.

Conus roseniaryac new species

(figures 34, 35)

material examined: HoIot>pe — Length 25 mm, trawled
by commercial fishermen from 85 m depth off Portobelo,
Panama. USNM 860546; Paratype 1— length 24 mm,
same depth and locality as holotype, Leonard Hill col-
lection, Miami, Florida.

Description: Shell small for genus, extremely pyriform,
turnip-shaped, wide across shoulder; shoulder carinated;
spire moderateK protracted, with concave whorls; body
whorl polished and shiny, faintly ornamented with nu-
merous low threads; spire whorls smooth; anterior third
of body whorl sculptured with 10 deeply-impressed wide
spiral sulci; body whorl white, overlaid with dense net-
work of large, amorphous, bright yellow-orange flam-
nuiles; some specimens (parat>pe) overlaid with .scat-
tered rows of dots; spire whorls white with scattered
large, amorphous yellow-orange patches and flammules;
ant(>rior tip of shell pale orange; protoconch and early
w horls orange; interior of aperture white; periostracum
thin, transparent tan, smooth.

E. J. Petuch, 1990

Page 69

•12

Figure 42. Map of the southwestern Caribbean Sea and the Panamanian Isthmus, show iiig the ilistribution of Caribbean molluscan
faunal subregions. H = Honduran Subregion; B = Blasian Subregion; CV = Colombian-Venezuelan Subregion (taken, in part, from
Petuch, 1988). Blasian geographical landmarks include the Laguna de Chiriqui (C), Portobelo (P), San Bias Archipelago (S), and
the Golfo de Uraba (U) As shown here, the Blasian Subregion may extend northward to the Costa Rica-Nicaragua border area,
in the vicinity of San Juan del Norte, Nicaragua.

Etymology: Named for Ms. Rosemary Adams of Sun-
nymead, California, who assisted Mr. James Ernest in
the collection of the new Blasian species.

Discussion: Of the known Blasian Conidae, Conns rose-
maryae is certainly one of the most distinctive. The pyr-
iform turnip shape of this new species is unique among
the Caribbean Panamanian cones. In general body form,
C. wsemaryae most closely resembles C. gibsonsmitho-
rum Petuch, 1986 from the Goajira Peninsula of Colom-
bia and the Gulf of Venezuela, but differs in being a
larger shell with a more elongated, tapered body whorl,
and in being narrower across the shoulder. Although both
C. gibsonsmithorum and C. wsemaryae have color va-
rieties with rows of dots, C. rosemaryae is a more heavily
patterned, more colorful species, with large orange flam-
mules (as in the holotype) covering most of the shell The
new species is also similar to C. sennottorum Rehder
and Abbott, 1951 from the Gulf of Mexico off Yucatan,
but differs in being a smaller, more slender, and more
brightly colored shell.

Turridae

Fusittirricula Woodring, 1928

Fusititrricula sundcrlandi new species
(figures 40, 41)

Material examined: Holotype — Length 33 mm, trawled
by commercial fishermen from 70 m depth off Portobelo,
Panama, USNM 860547.

Description: Shell extremely elongated, slender, and
fusiform; spire very elevated and protracted, turriculate;
shoulder sharply-angled, with 12 oval-shaped knobs per
whorl along periphery; subsutural area sloping; body
whorl below shoulder knobs ornamented with 10 large
beaded spiral cords; subsutural area ornamented with
numerous extremely fine spiral threads; margin of suture
bordered bv bands of small, closely-packed oblong pus-
tules; siphonal canal elongated, narrow, straight, orna-
mented with numerous fine, beaded, spiral threads, shell
color uniformly pinkish-tan; aperture and columella
white

Page 70

THE NAUTILUS, Vol. 104, No. 2

Etymology: Named for Mr. Kevan Suntlerlaml of Fort
Lauderdale, Florida, who kindly donated the holotype

Discussion: Fusiiurricula sunderlandi is most similar
to the Panamic species, F. armilda (Dall, 1908), but dif-
fers ill heiii^ a more slender, fusiform shell with a more
elongated body whorl. In F. armilda. the body whorl
pinches-in abruptly at the junction with the siphonal
canal, while in C sunderlandi, the body whorl tapers
gradually into the siphonal canal. The two species pos-
sibK form a cognate pair.

Knefasiia Dall, 1919

Knefastia hilli new species
(figures 38, 39)

Material examined: Holot\pe — Length 50 mm, trawled
bv commercial fishermen from 70 m depth off Portobelo,
Panama, USNM 860548.

Description: Shell large, robust, fusiform; spire very
high, elevated, distinct!) turriculate and scalaritorm;
subsutural area flattened, producing stepped spire whorls;
whorls ornamented with 8 large, rounded, elongated,
\ari.\-like axial knobs; body whorl ornamented with 12
large, pustulated spiral cords with one or two fine, pus-
tulated secondary cords in between; pustulated cords
overlie large axial knobs; siphonal canal short, stubby,
ornamented with 8 large, pustulated cords; fine cords
and threads present between main siphonal cords; outer
lip with numerous lirae along inside edge; anal notch
small, narrow; shell color orange-brown with darker
brown knobs; primary cords on spire, body whorl, and
siphonal canal white or light tan; body whorl-siphonal
canal junction marked with wide, dark brown band; an-
terior end of siphonal canal circled by wide, dark brown
band; aperture and columella pale orange-tan.

Etymology: Named for Mr. Leonard C. Hill of Miami,
Floritla.

Discussion: Knefastia hilli is the first-known living At-
lantic species of this primarily Panamic genus, Knefastia
hilli is most similar to K. olivacea (Sowerby, 1833), which
ranges from the Gulf of California southward to southern
Ecuador. The new Caribbean species differs from K.
olivacea in being a smaller shell with larger and more
pronounced a.xial knobs, and in having finer and more
numerous spiral cords. The two species, however, are
very similar and, no doubt, represent Panamic-Carib-
bean cognates.

ACKNOWLEDGEMENTS

I thank Mr. Leonard Hill of Miami, Florida, for the
donation of the valuable research material collected bv

Mr. James Ernest. Thanks also to Mr. Kevan Sunderland,
Fort Lauderdale, Florida, for the donation of the new
Fusiturricula species. Special thanks go to Mrs. Cynthia
Mischler, Department of Geology , Florida Atlantic Uni-
versity, for patiently typing the manuscript and to Mr.
William Lyons, Division of Marine Resources, Florida
Department of Natural Resources, for valuable ocean-
ographic data and critical review.

LITERATURE CITED

Houbrick, J. R. 1968. A survey of thf littoral marine mollusks
of the Caribbean coast of Costa Rica Thf Wliger 11(1):
4-23.

Olsson, A. A. and T. L McGinty 1958 Recent marine mol-
lusks from the Caribbean coast of Panama with the de-
scription of some new genera and species. Bulletins of
American Paleontology .39(177):5-.59.

Petuch, E. J. 1980. A relict caenogastropod fauna from north-
ern South America. Maiacologia 20(2)307-347,

Petuch, E. J. 1981. A voiutid species radiation from Northern
Honduras, with notes on the Honduran Caloosahatchian
Secondary Relict pocket Proceedings of the Biological
Society of Washington 94(4): 1 1 10-1130.

Petuch, E. J. 1982. Geographical heterochrony: contempo-
raneous coexistence of Neogene and Recent molluscan
faunas in the Americas. Palaeogeography, Palaeoclima-
tology, and Palaeoecology 37:277-312.

Petuch, E. J. 1987. New Caribbean molluscan faunas The
Coastal Education and Research Foundation. (Charlottes-
ville, VA, 1.54 p

Petuch. E J. 1988 Neogene histor\ of tropical .\merican
mollusks. The Coastal Education and Research Foimda-
tion, Charlottesville, VA, 217 p

Petuch, E. J. and D. M. Sargent. 1986. Atlas of the living
olive shells of the world. The Coastal Education and Re-
search Foundation, Charlottesville. WA, 253 p

Radwiii, G. E. 1969. A Recent molluscan fauna from the
Caribbean coast of Panama Transactions of the San Diego
Society of Natural History 15(14):229-2.36.

Radwin, G E. and A. D'AttiJio. 1976. Murex shells of the
world. Stanford University Press, Stanford, CA, 284 p.

Valentine, J. W. 1973. Evolutionary paleoecology of the ma-
rine biosphere Prentice-Hall, Inc , Englewood, NJ, 511 p.

\ ernu'ij. i'. J 1978. Biogeography and adaptation: patterns
oi marine life Harvard llni\ersit\ Press. C'ambridge, M.'^,
332 p,

Vokes, E, H, 1975, Cenozoic Muricidae ol the Western M-
lantic Region. Part VI Aspella and Dcrrnomurex. Tulane
Studies in Geology and Paleontology 11(3):121-162.

\'okes, E. H. 1985. Review of the West Coast Aspelloids
Aspella and Dermomurex (Gastropoda: Muricidae), with
the Descriptions of Two New Species. The Veliger 27(4):
430-439

Whilmore, F C and R H Stewart 1965 Miocene mammals
ami Central .•\meritan seawa\s Science 1 48: 1 80- 1 8.5.

Wooilring, W. P. 1966 The I'anania land bridge as a sea
barrier Proceedings ol the American Philosophical Society
110 42.5-43.3.

THE NAUTILUS 104(2):71-75, 1990

Page 71

Morphological Comparisons of the Species of
Megapallifera (Gastropoda: Philomycidae)

H. Lee Fairbanks

Pennsylvania State I'niversit)
Beaver Campus
Monaca, PA 1.5061, USA

ABSTRACT

Specimens of all three species of Megapallifera. M mutabilis.
M. uetherbyi. and M. ragsdalei. were collected from their t\ pe
localities. The external morphology and reproductive s\stem
anatomy of each of these species was compared. Mantle color
and pattern of M. mutabilis is different from those of M. weth-
erbxji and M. ragsdalei. Differences among the three species in
penial anatoms and in morphology of the lobes in the upper
atrium support ta.\onomic separation of the three species.

Keij words: Philomycidae; Megapallifera, morphology; re-
[jroductive-system anatomy.

INTRODUCTION

The Philomycidae are a family of terrestrial slugs native
to the eastern and south-centra! United States and eastern
Asia. There are three genera in the famiK : Philomycus,
Pallifera, and Megapallifera. The slugs in the genus
Philomtjciis are large and have a dart sac and dart, those
in the genus Pallifera are small and lack the dart sac
and dart. The slugs in the genus Megapallifera also lack
the dart sac and dart and were first placed in the genus
Pallifera. Hubricht (1956) established Megapallifera as
a subgenus of Pallifera, and cited five characteristics for
its species: (1) gray or white foot margins, (2) ribbed jaw,
(3) large size, (4) chevron-shaped transverse bands on
the mantle, and (5) a pilaster extending from the lower
vagina into the upper atrium. The latter three charac-
teristics separated Megapallifera from Pallifera. Hu-
bricht (1976) elevated Megapallifera to generic rank,
with M. mutabilis (Hubricht, 1951), as the type species,
and included M. wetherbyi (Binney, 1874) and M. rags-
dalei (Webb, 1950). Webb (1950, 1951) discussed the
reproductive-system anatomy of M. ivetherbiji and M.
ragsdalei (as a species and subspecies respectively of
Eitmelus), but data concerning the internal anatomy of
the atria and penes were incomplete or absent. When
Hubricht described M. mutabilis, he did not figure the
reproductive-system anatomy. Branson (1962) synon-
omized M. mutabilis with M. ragsdalei, apparently on
the basis of external morphology, without providing sup-
porting data. No comparative studies have been con-
ducted involving all three species of Megapallifera.

The objectives of this investigation were: (1) to char-
acterize and compare the external morphologies of each
of the species of Megapallifera and (2) to compare the
reproductive systems of these species in order to deter-
mine species specific characters.

METHODS AND MATERIALS

Specimens of Megapallifera mutabilis were collected on
18 May 1989 at the t\pe localitv (just west of Schoolfield,
Pittsylvania County, Virginia), elevation approximately
150 meters, under loose bark of dead trees. Specimens
of M. wetherbyi were collected on 23 May 1987 and 16
May 1989 at the type locality (near the mouth of the
Laurel River, Whitley County, Kentucky), elevation ap-
proximately 245 meters, on sandstone cliffs. One speci-
men of M. ragsdalei was collected on 3 April 1988 from
the t\pe locality (9.5 kilometers east of Calico Rock, on
State Route 56, Izard County, Arkansas), elevation ap-
proximately 125 meters, under moss on a sandstone cliff.
Additional specimens of M. ragsdalei. collected 25 .-^pril
1982, at Devils Den State Park, Crawford Count), .Ar-
kansas (preserved in ethanol) were obtained on loan from
the Field Museum of Natural History, Chicago, Illinois
(FMNH 210285).

External characteristics were compared with species
descriptions to ensure correct identification of all spec-
imens. Mantle color, mantle pattern and foot margin
color were compared among species. The live specimens
were drowned in distilled water and immediately dis-
sected. The reproductive svstems of the specimens dis-
sected were removed and opened so that the internal
structure of the atrium and penis could be described.
Measurements were taken of eight reproductive struc-
tures (length of penis, length of apical chamber of penis,
length of penial retractor muscle, length of spermathecal
duct, length of vagina, length of oviduct, length of vas
deferens, and length of hermaphroditic duct). All ma-
terial was preserved in 70% ethanol subsequent to dis-
section. DroNMiings and dissections of the live specimens
were conducted during the same time period (1-12 June)
in each year to control for differences in anatomy at-
tributable to phases of the life cycle.

All drawings are tracings of the systems or organs

Page 72

THE NAUTILUS, Vol. 104, No. 2

<l*.

'\^

^ts

Figures 1-3. Mantle patterns. 1. Megapallifera mutabilis. 2. Megapallifera wetherbyi. 3. Megapallifera ragsdalei. Scale bar
equals 10 mm

Table 1 . Length comparisons of eight reproductive structures (means with ranges in parentheses) and results of anal\ sis of variance
tests Measurements in millimeters

M. mutabilis

M. wetherbyi

M. ragsdalei

(N = 3)

(N = 2)

(N = 3)

Length of slug-

60 0

71,5

,5(),(^'

—

(55.0-65.0)

(68.0-75.0)

—

Penis

11.6

16,7

13.1

8.22

0,026^

(10.7-12.6)

(16,1-17,3)

(11.2-15,0)

Apical chamber

1.7

2,6

1.7

6.74

0.038^

(1.6-1.8)

(2.2-3,0)

(1.5-2.0)

Penial retractor

146

7.8

8.3

3.00

0 139

(10.0-20.3)

(6.8-8.8)

(6.7-10.8)

Spermathecal duct

10.3

13.2

10.9

3,11

0 132

(8.6-11.5)

(11.8-14.6)

(10.8-11.0)

Vagina

1.7

1.6

004

0.966

(1.5-1.9)

(-)

(1.0-2.7)

Oviduct

9.1

15.8

9.4

2.87

0.148

(6.8-12.6)

(12.2-19.3)

(6.8-11.4)

Vas deferens

18.7

34.5

28.1

5.48

0.055

(15.1-32.2)

(29.9-39.1)

(23.5-35.2)

Hermaphroditic duct

28.9

40.0

23,3

7.35

0,032^

(23,8-32.2)

(.^4. 4-155)

(20 8-25 5)

' Dciir.'cs of freedom 2 and 5.

- Crawling.

^Oniy one living specimen was obtained.

* Signifii ant difference at 5% level.

H. L. Fairbanks, 1990

Page 73

Table 2. Results of the Modified Duncan Multiple Range Tests.
Means (in millimeters) underscored by the same line are not
significantly different at the 5% level. A, Mcgapallifera mu-
tahilis. B, Megapallijera wcthcrlnji: C, Megapallifera rags-
dalci.

Species

L.ength of penis

Lengtii of apical chamber

11.57
l,(i7

13 01

1 73

l(i,7()
2,60

Species

Length of hermaphroditic

ict

23 33

2S93

39 9.)

figured The reproductive system was traced from a spec-
imen pinned out in a \va.\-bottom petri dish and pro-
jected, via an overhead projector, onto 8'/2 x H paper.
The atrial and penial figures are tracings of photographic
slides projected onto 8'/2 x 11 paper. Voucher specimens
have been deposited in the National Museum of Natural
History. Smithsonian Institution (USNM S54012 for
Megapallifera ragsdalei; USNM 854013 for M. weth-
erbyi. L'SNM 854014 for M. mutabilis).

Analysis of variance was used to compare the means
of measurements of reproducti\'e organs. After the anal-
ysis of variance tests were conducted, a modified Duncan
Multiple Range Test (Kramer, 1956) was used to deter-
mine which means, among those compared in a given
ANOX'A, were significantly different.

RESULTS

E.XTERNAL Characters

All living specimens attained crawling lengths that varied
between 50 and 75 millimeters (figures 1-3). All had
some transverse chevron-shaped bands on the mantle
(figures 1-3). All had gray or white foot margins.

The mantle color of Megapallifera mutabilis was fawn
or tan whereas the mantle color of M. ivetherbiji and M.
ragsdalei was gray. The "spots" that produce the mantle
pattern were light to dark brown in all three species;
however, the arrangement of those spots varied among
species. Both M. wetherbtji and M. ragsdalei had broad
distinct chevrons in their mantle pattern (figures 2, 3).
In M. mutabilis the mantle pattern was a series of spots
that in some cases produced vague chevrons on the man-
tle (figure 1).

Observed habitat preferences varied among the species.
Megapallifera mutabilis preferred old-growth decidu-
ous forest, whereas M. wetherbyi and M. ragsdalei pre-
ferred areas in which sandstone outcrops and cliffs were
common.

Reproductive System Characters

Comparisons of length measurements of some repro-
ductive structures are shown in table 1. Analysis of vari-
ance tests (table 1) indicated three significant differences

Figures 4-6. Genitalia, 4. Megapallijera wetherbyi. .5. Mcga-
pallifera ragsdalei. 6. Megapallifera nuilahilis. Scale bar e(|uals
10 mm .'\C, apical chamber; ,-\G, albumen gland, (.',. gonad;
HD, hermaphroditic duct; L.\, lower atrium; P, penis; PR,
penial retractor; SD. spermathecal duct; I'A, upper atrium;
L'V, free oviduct; V, vagina; VD, vas deferens.

among species. For each of these tests, the Modified
Duncan Multiple Range Tests (table 2) indicated which
of the species were significantly different from the others.
All specimens had an atrium with two "parts", a lower
atrium and an upper atrium (figures 7-9). The external
surface of the lower atrium (lying within the body cavity)
was covered with glandular material (figures 4-6), the
internal surface was relatively smooth (figures 7-9). The
color of the glandular material on the outside surface of
the lower atrium varied among species: light orange for
Megapallifera wetherbyi. white for M. ragsdalei. cream
for M. mutabilis. The external surface of the upper
atrium, in all specimens, was nonglandular, and had ac-
cessory retractor muscles located near the origin of the
vagina (figures 4-6). Internally, the upper atrium con-
tained two labia-like lobes, one on either side of the
opening to the penis (figures 7-9). In M. mutabilis these
lobes were the least complex, having two or three folds
that divided a lobe into sublobes (figure 9). In M. weth-
erbtji the primary lobes had two to three folds (figure 7)
whereas M. ragsdalei had four or fi\e sublobes (figure
8).

Page 74

THE NAUTLIUS, Vol. 104, No. 2

Figures 7-9. Internal details of the atria. 7. Mcgapallifera
wethcrbyi. 8. Mcgapallifera ragsdaln. 9. Mcgapallifera niu-
tahilis. Scale bar equals 10 mm. AL, atrial lobes; LA, lower
atrium; P, penis; PO, penial opening; SD, spermathecal duct;
UA, upper atrium; UV, free oviduct.

The penes of all specimens had an apical chamber at
the vas-deferens end, i.e.. a part of the penis set off by
an internal constriction (figures 10-12). The size of the
apical chamber varied among species (table 1), but in-
ternally there was little variation in the pattern of folds
and pilasters among species. Internally, below the apical
chamber, the penis of M. mittabilis had five to seven
(justulose pilasters that began at the vas-deferens end and
gradually disappeared at approximately the midpoint of
the penis (figure 12). The remainder of the penis, inter-
nally, was pustulose. The penis of M. ragsdalei had seven
to nine pustulose pilasters that ran the entire length of
the penis (figure 11). The internal penial anatomy of M.
wetherbyi (figure 10) was similar to that of M. ragsdalei
(figure 11). All specimens lacked a penial sheath (figures
10-12).

DISCUSSION

The external characteristics, mantle color and mantle
pattern, of Mcgapallifera mutabilis were clearly differ-
ent from both M. wetherbyi and M. ragsdalei (figures
1-3). In addition, the internal morphology of the penis
(figures 10-12) and the shape of the upper atrial lobes
(figures 7-9) of M. mutabilis were different from those

Figures 10-12. Internal detail of the penes 10. Mcgapallif-
era wetherbyi. 1 1. Mcgapallifera ragsdalei. 12. Mcgapallifera
mutabilis. Scale bar equals 10 mm. AC, apical chamber; PR,
penial retractor; \'D, vas deferens.

of both M. wetherbyi and M. ragsdalei. Significant dif-
ferences between the mean lengths of the penis and the
apical chamber of the penis (table 2) were demonstrated
between M. mutabilis and M. wetherbyi. These data
support the species status of M. mutabilis.

External morphological data supporting the separation
of Megapallifera wetherbyi from M. ragsdalei were not
conclusive (figures 2, 3). However, internal morpholog-
ical data supported specific-level separation of these two
taxa. Mean lengths of the penis, the apical chamber of
the penis, and the hermaphroditic duct for M. tvetherbyi
were significantly greater than those of M. ragsdalei
(table 2). In addition, the lobes in the upper atrium of
the former were different from those of the latter (figures
7, 8). Hubricht (1956) mentioned a pilaster that extended
from the lower vagina into the upper atrium Webb
(1950) mentioned a single pilaster or a bilobed pilaster
in the upper atrium. Neither author figured the lobes in
the uneverted condition. This study has demonstrated
that there are two separate lobes located in the upper
atrium, one on either side of the opening into the penis

H. L. Fairbanks, 1990

Page 75

and below the opening into the vagina. In addition, these
lobes were, in some specimens, quite complex. In these
three species the most obvious reproductive-system dif-
ferences were in these lobes, i.e.. all three species were
easily separated on the basis of these lobes alone (figures
7-9). Webb (1951) made note of the atrial lobes during
studies of the courtship between two M. wetherhiji. The
lobes were referred to as "hoods", in their everted shape,
and they appeared to play a significant role in premating
behavior. In view of the apparent function of these lobes
it seems appropriate, for these three species, to attach
considerable significance to atrial lobe differences.

In summary, this study demonstrated species-specific
morphological differences, both external and internal,
between Megapallifera mutabilis, M. wetherbyi, and M.
ragsdalei.

ACKNOWLEDGEMENTS

Thanks go to Susan McKee, who was the onlv person to
find a live specimen of Megapallifera ragsdalei at the
t\ pe locality. Thanks also go to Dr. Richard Reeder, who
helped locate specimens used in this study, and provided
valuable comments concerning the writing of this paper.
Financial support for field work was provided by grants

from the Research Development Grant iMind of Penn-
sylvania State University.

LITER.4TL RE CITED

Binne\, W. G. 1874. On tlie genitalia and liguai dfiititioii of
Pulmonata. .Annals of the Lyceum of Natural Histor\ of
New York 11:20-46, pis. 1-6.

Branson, B. A. 1962. The slugs (Gastropoda: Pulmonata) of
Oklahoma and Kansas u itii new records. Transactions of
the Kansas Academy of Science 65(2):110-119.

Hubricht, L. 1951. Three new land snails from eastern L^iited
States. The Nautilus f55(2):57-59.

Hubricht, L. 1956. Megapalliffra. nt-w subgenus. The Nau-
tilus fj9(4): 126.

Hubricht, L. 1976. Notes on some land snails of the eastern
United States. The Nautilus 90(3):104-107

Kramer, C. Y. 1956. Extension of multiple range tests to group
means with unequal numbers of replications. Biometrics
12:307-310.

Webb, G B 1950 New and neglected philonncids and the
genus Eumclu.s Bafinesque (Mollusca. Gastropoda, Pul-
monata). Transactions of the American Microscopical So-
ciety 69(l):54-63.

Webb, G B 1951. Notes on the sexology of philomycid slugs
of the genus Eumelus Bafinesque. Journal of the Tennessee
Academy of Science 26(l):73-78.

THE NAUTLIUS 104(2):76

Page 76

Ovophagy in Anachis avara (Say, 1822)
(Gastropoda: Columbellidae)

\I. G. Harasewych

Department of Invertebrate Zoology
National Museum of Natural History
Smithsonian Institution
Washington, DC 20560, L'SA

Five strands of egg cases of Melongena corona altispira
Pilsbry and X'anatta, 1934, were collected in the Indian
River, near VVabasso, Indian River County, Florida in
July of this year and maintained in a recirculating sea-
water table together with appro.ximately fifty specimens
of Melongena corona altispira. When examined after
several hours in the seawater table, si.x specimens of An-
achis avara (Say, 1822) were found on the egg capsules.
The Anachis were removed and returned to the table
approximately one meter from the egg cases. The cap-
sules were examined and placed in a large bowl, the rim
of which e.xtended above the water level in the seawater
table by two centimeters. Seawater flowed into the bowl,
overflowing the rim into the table.

The following morning (12 hours later) four of the six
specimens of Anachis avara in the seawater table were
again on the flat sides of the egg capsules, each on the
terminal capsule of a strand. When examined under a
dissecting microscope, the columhellids were observed
to have penetrated the walls of the egg cases near the
centers of the capsules, and to be feeding on the Melon-
gena larvae and on the dense inner layer of albuminous
fluid (figure 1). To reach the egg capsules, the Anachis
had to crawl past two large Mercenaria mercenaria that
had been cracked open and placed in the tank to feed
the Melongena.

Although there was not sufficient time to repeat these
observations with appropriate controls, it seems clear that
Anachis avara is capable of locating gastropod egg cases
at considerable distances by chemosensory means. It is
unclear whether Anachis avara showed a preference for
egg cases over Mercenaria mercenaria, or if it was de-
terred from feeding on the bivalves by the presence of
feeding Melongena.

Members of the family Columbellidae have extremely
diverse and opportunistic diets that may consist of poly-
chaetes, small Crustacea, a.scidians, hydroids, algae, or-
ganic detritus and carrion (Hatfield, 1979; Taylor et ai,
1980). Taylor (19S7) reported that six of 16 specimens

Figure 1. .\nachi.s avara feeding on
cunma altispira.

Mel,

Hungena

of Mitrella scripta examined contained gastropod eggs
in their stomachs. The present observations suggest that
gastropod eggs represent a significant dietar\' item for
at least some species of columhellids

This is contribution number 264 of the Smithsonian
Marine Station at Link Port.

LITERATURE CITED

llathekl, E 15 1979. Food sources for Anachis avara (Col-
uinhellidae) and a discussion of feeding in the family. The

Nautilus 93(l):40-4.3.

Taylor, J. D. 1987. Feeding ecolog) of some corninon niter-
tidal iieogastropods at Djerba. Tunisia \'ir \lillicu •')7(1):
1.3-20,

Ta\l(M, J I), \ J NU.rris. and C N. Tavlor 19S0. Food
sptTi.ili/alioii and the e\'olution of predatory prosobraneh
gastropods J'alaeontologN 23(2):375-409.

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rHE NAUTILUS

Volume 104, i\ umber 3
October 11, 1990
ISSN 0028-1344

A quarterly devoted
to malacology.

Marine Bi"'"^''^"^' laboralo:

OCT 19

'— '- Mole, Mass. ^

EDITOR-IN-CHIEF
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Division of Mollusks
National Museum of
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Smithsonian Institution
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Delaware Museum of
Natural History
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National Museum of
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Museum of Comparative Zoology
Harvard University
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Department of Geology
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Department of Malacology
Los Angeles County Museum of
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THE

AU T I L U S

CONTENTS

Volume 104, Number 3
October 11. 1990

ISSN 0028-1344

-■jjrdior;

James H. McLean

A new genus and species of neomplialid limpet from the
Mariana Vents w ith a review of current understanding gf
relationsfiips among Neomphalacea and Peltospiracea

R. Douglas Hunter

Shell dissolution rate in fresh .vater pulmonate snails:
influence of periostracuni and water chemistry . .

Thomas Stahl
David M. Lodge

Effect of experimentally induced shell damage on
mortality, reproduction and growth in Helisoma trivolvis
(Say, 1816)

Edward J. Petuch

New gastropods from the Bermont Formation (Middle
Pleistocene) of the Everglades Basin

B. A. Marshall

Micropilina tangaroa, a new monoplacophoran (Mollusca)
from northern New Zealand

105

William K. Emerson
Walter E. Sage, III

Addenda to "Distorsio ridens (Reeve, 1844); A synonym of
Distorsio clathrata (Lamarck, 1816) (Gastropoda:
Personidae)"

108

THE NAUTILI'S 104(3):77-86, 1990

Page

A New Genus and Species of Neomphalid Limpet from the
Mariana Vents with a Review of Current Understanding of
Relationships among Neomphalacea and Peltospiracea

James H. McLean

Lui Angeles Count) Museum of

Natural History
900 Exposition Boulevard
Los Angeles, CA 90007, USA

ABSTRACT

Symmetromphalus regularis new genus, new species, is de-
scribed from Intlrothermal vents of the Mariana Back Arc
Basin. It differs from Seornphalufi jretterae McLean, f9SI, in
having; the opening of the mantle cavity directed anteriorK
rather than to the left, more numerous epipodial tentacles, the
operculum retained in the adult, and in a deep sperm groove
on the left cephalic tentacles of males.

The famil) Cyathermiidae is here proposed for two coiled
members of the superfamiK Neomphalacea, the genera Cya-
thermia and Lacunoides. both of VVaren and Bouchet (1989),
The family Cyathermiidae is characterized by: a short snout,
a closed sperm groove along the left cephalic tentacle, and two
cirri at the tip of the left cephalic tentacle

Neomphalacea can be associated with Peltospiracea in a sub-
order Neomphalina, on the basis of shared characters (non-
nacreous shell, monotocardian heart, bipectinate gill, lack of
ctenidial bursicles, similar radula). As these may be plesio-
morphic or convergent characters, further anatomical com-
parisons are needed to establish additional synapomorphic char-
acters for such a suborder .\ fossil record of the newly expanded
complex is yet elusive, but should continue to be sought.

Key words: .\rchaeogastropoda; Neomphalacea; Symmetrom-
phalus, Cyathermiidae; Peltospiracea; hydrothermal-vent lim-
pets; Mariana Vents.

INTRODUCTION

Neomphalus fretterae McLean, 1981, the largest and
most densely aggregated of hvdrothermal-vent limpets,
was the first vent-limpet to be described (McLean, 1981).
Its anatomy was treated in an accompanying paper by
Freneret al. (1981). Although I expected that additional
species of Seomphalus would eventually be found at
other sites, none were found until the fauna of the Mar-
iana Back .\rc Basin was sampled in 1987, at which time
a new, monotypic genus in the family Neomphalidae
was discovered. The primary objective of this paper is
to provide the formal description of the new genus and
species Symmetromphalus regularis.

Recently, an affinity with Neomphalus w as recognized
in two coiled genera described by Waren and Bouchet
(1989) from Eastern Pacific hydrothermal vents: Cya-
thermia and Lacunoides. These small-shelled, monotyp-
ic genera are regularly coiled and have many of the
diagnostic features common to Neomphalus. although
they share other unique features, which indicate that
they in turn should be segregated within their own fam-
ily. Accordingly, the family Cyathermiidae is here pro-
posed.

Higher classification of Neomphalacea and the re-
cently proposed and probably related Peltospiracea Mc-
Lean ( 1 989a) has been discussed by Haszprunar ( 1 988a,b,
1989), Waren and Bouchet (1989), and Fretter (1989).
Another objective of this paper is to briefly review the
current work that assesses these relationships, noting the
gaps in our understanding of anatomy in certain mem-
bers.

My early interpretation of the possible fossil affinity
of Neomphalus has generated some controversy ; here I
take the opportunity to review these criticisms and offer
a revised assessment of the potential for a fossil record
of the groups treated here.

MATERIALS AND METHODS

The new species described here was first collected w ith
the deep-submersible Alvin in May, 1987, at hydrother-
mal vents of the mid-Pacific Mariana Back .^rc Basin. A
general description of the site was given b\ Hessler et
al. (1988). Until now, two other gastropods, Alvinocon-
cha hessleri Okutani and Ohta, 1988, and Pseudorimula
marianae McLean, 1989b, have been described from
these vents.

Limpet specimens were collected w itli the mechanical
arm of the Alvin in the course of collecting substrate
samples and general collecting of all organisms. Material
was preserved upon reaching the surface and was orig-
inally fixed for 24 hours in lO^c seawater formalin buf-
fered with sodium borate, washed in fresh water, and
transferred to 70% ethanol (for details of collecting pro-

Page 78

THE NAUTILUS, Vol. 104, No, 3

cedures see Turner et ai, 1985). Preserved specimens
were sorted at Scripps Institution of Oceanography and
forwarded to me by Robert R. Hessler.

Radulae were extracted from preserved specimens af-
ter dissolution of tissues with 10% NaOH for 48 hours,
air dried and coated with gold palladium for SEM ex-
amination. Juvenile shells with protoconchs were ex-
amined with SEM. Protoconch lengths were taken di-
rectly from scale indications for the SEM micrographs.

Repositories of the t\pe material are the Los Angeles
County Museum of Natural History (LACM), the United
States National Museum (USNM), and the Museum Na-
tional d'Histoire Naturelle, Paris. All figured specimens
are deposited at the LACM.

phalic lappets. Eyes lacking, epipodial and cephalic ten-
tacles non-papillate, left cephalic tentacle of male mod-
ified to function as penis, sperm groove open or closed.
Gonad with glandular gonoducts, dorsal to digestive gland
and intestine; females with seminal vesicle.

Radula rhipidoglossate, cusps of all teeth aligned in
descending rows, shaft lengths of all teeth increasing
toward edge of ribbon. Rachidian tooth with shaft broad
at base and acutely pointed overhanging cusp. Lateral
teeth four pairs, inner surfaces excavated to articulate
with rachidian or adjacent lateral teeth, overhanging
cusps of laterals like those of rachidian tooth. Marginal
teeth numerous, shafts wide but incompletely separated
at base, tips deeply serrate.

SYSTEMATICS

Superorder ARCHAEOGASTROPODA
Thiele, 1925

Recent authors (Salvini-Plawen, 1980; Salvini-Plawen &
Haszprunar, 1987; Haszprunar, 1988a, b; Hickman, 1988)
have discussed the problems inherent in the "archaeo-
gastropod" concept, pointing out that Archaeogastrop-
oda, as traditionally constituted (Thiele, 1925; Knight et
ai, 1960) represents a grade.

Hickman (1988) redefined Archaeogastropoda to in-
clude superfamilies Pleurotomariacea, Fissurellacea, and
Trochacea, stating that it was thereby synonymous with
Haszprunar's concept of Vetigastropoda Salvini-Plawen,
1980. However, Haszprunar (1988a, b) also included Le-
petodrilacea McLean, 1988, in Vetigastropoda, which
inclusion was overlooked by Hickman (1988) and also
by Bieler (1990:380) in hiscritic}ueof Haszprunar's work.
I follow Haszprunar ( 1988a, b) in retaining the traditional
meaning of Archaeogastropoda, allowing it to be ex-
pressly indicated in a classification as an orthophyletic
grade.

Superfamily NEOMPHALACEA McLean, 1981

The diagnosis that follows encompasses two families, the
Neomphalidae and the Cyathermiidae new family, tak-
ing into account the characters of the two coiled genera
described by Waren and Bouchet (1989). It will, how-
ever, need to be modified once the internal anatomy of
all genera becomes known.

Diagnosis: Shell regularly coiled or of limpet form, lack-
ing nacre, periostracum thick; first telcoconch whorl with
oblique aperture and rounded whorls, regularly coiled
in all genera; protoconch with net-pattern surface sculp-
ture; opercuhnn multispiral initially, final volution en-
larged, retained at least through the first telcoconch whorl
in all members

Monotocardi^Hi. ventricle not penetrated by rectum;
left kidney only. tJtenidiurn bipectinate, afferent mem-
brane lacking or ver\ short, gill axis producing sturdy
free tip, filaments elongate, skeleton lacking bursides.
Perioral surface with transverse furrow extending to ce-

CYATHERMIIDAE new family

Diagnosis: Shell coiled through teleoconch; sculpture
smooth to finely reticulate. Neck short; short snout pres-
ent; cephalic tentacles anterio-lateralK directed; en-
larged left tentacle serving as penis, sperm groove of
enlarged left tentacle closed, tip with two prominent
cirri. Afferent ctenidial membrane ver\ short. Cusps of
rachidian and lateral teeth finely serrate, cusp of ra-
chidian tooth much longer than those of inner lateral
teeth.

Included genera: Cyathermia Waren and Bouchet, 1989,
and Lacunoides Waren and Bouchet, 1989. Cyathermia
is monotypic for C. naticoides Waren and Bouchet, which
is widely distributed on the East Pacific Rise. Lacunoides
is monotypic for L. exqiiisitus Waren and Bouchet, known
only from the Galapagos Rift.

Remarks: Separation of the two monotypic coiled gen-
era from the two monotypic limpet genera is now ap-
propriate at the familial level, given that each of the two
groups of genera have synapomorphic characters in com-
mon. Diagnostic characters of the Cyathermiidae are the
short snout, left cephalic tentacle with closed sperm groove
and two cirri at the tip, serration of rachidian and lateral
teeth and enlargement of rachidian tooth. See Waren
and Bouchet (1989) for more detailed descriptions of
these two genera.

Family NEOMPHALIDAE McLean, 1981

Diagnosis: Shell coiled through first teleoconch whorl,
changing to limpet form in second teleoconch whorl;
sculpture of strong radial ribs. Neck long; snout lacking
in adult; cephalic tentacles posteriorly directed; sperm
groove of enlarged left tentacle open; cirri at tip of penis
lacking. Cusps of rachidian and lateral teeth non-serrate,
cusp of rachidian tooth of same length as those of inner
lateral teeth.

Included genera: Meornplialiis McLean, 1981, and
Symmetromphalus new genus, Neomphalus is mono-
typic for N, fretterae McLean. 1981, known from the
Galapagos Rift (the type locality) and from sites on the
East Pacific Rise. Syinmetroniphalus is monotypic for S.

J. H. McLean. 1990

Page 79

regtdaris new species, known onl\ from the Mariana
Back Arc Basin vents.

Remarks: Diagnostic characters of the Neomphahdae
are the limpet form of the mature shell, absence of snout,
posterior direction of cephalic tentacles, open sperm
groove and lack of cirri on the enlarged left tentacle. See
Fretter et al. (1981) for a more detailed description of
anatomy in Neomphalus fretterae.

Symmetromphalus new genus

Type species: Sijmmetromphalus regularis new species.

Description: Shell of limpet form, mantle cavity and
horseshoe-shaped muscle open anteriorly; shell outline
symmetrical in juvenile, irregular in mature specimens;
coiled apical whorl offset to right. Sculpture of finely
beaded radial ribs; operculum present in adult. Neck
long, perioral surface with transverse furrows extending
to cephalic lappets. Cephalic tentacles short, posteriorly
directed, left tentacle of male greatK distended, deep
dorsal sperm groove connecting with groove on left side
of neck. Epipodial tentacles present posteriorly and lat-
erally. Gill bipectinate, afferent membrane lacking, fil-
aments elongate, efferent axis of free tip extended over
long neck. Radula rhipidoglossate, four pairs of lateral
teeth, cusps similar to those of rachidian teeth, except
fourth lateral teeth strongK' serrate on outer edge; mar-
ginal teeth numerous.

Remarks: On characters of external anatomy, Sym-
metromphalus differs from Neomphalus in its: anterior
rattier than leftward opening of the mantle ca\it> and
shell muscle, its evenly distributed rather than posteriorly
grouped epipodial tentacles, smaller cephalic tentacles,
greater prominence of sperm groove in enlarged left
cephalic tentacle, and apparent absence of well-defined
food groove. The shell differs in ha\ing strong beading
on early ribs and lacking the interior ridge. A vestigial
operculum is present in mature specimens. The radula
is similar in both genera.

Most of these distinctions are regarded as significant
at the generic level. Only the sculptural difference
(prominent beading rather than smooth ribs) is consid-
ered a species-level difference by itself.

Names of both the new genus and species emphasize
the regular and symmetrical aspect, in contrast to the
leftward shift of the mantle cavit\ that characterizes
Seomphalus.

Symmetromphalus regularis new species
(figures 1-17)

Description: Shell (figures 1-3, 7-10, 17) of medium
size for family (maximum length 14.0 mm for females,
10.6 mm for males), white under thick, pale tan perios-
tracum, which projects beyond edge of shell. Profile mod-
eratel) elevated; juvenile shell nearly symmetrical, out-
line of mature shell irregular, indicating habitual site of

attachment. Apical whorl markedK posterior in juvenile
shell (figures 11, 12), closer to center in mature shell.
I'rotoconch (figures 13. 14) length 220 ^^\, surface sculp-
ture of irregular network of low ridges. First teleoconch
whorl rounded, suture deep, coiled through one-half whorl
of growth. Limpet form attained after completion of first
teleoconch whorl; growth of posterior slope beginning at
shell length of 1.5 mm. Radial (spiral) sculpture arising
at shell length of 1 mm, consisting of low primary cords
on which beading appears at shell length of 2 mm. Sec-
ondary cords arise at shell length of about 7 mm. quickly
assuming size of primary cords; cords at margin very
narrow, retaining beading, interspaces broad. Shell in-
terior glossy white. Muscle scar horseshoe-shaped, open
anteriorly, broad throughout, except posteriori}-; anterior
terminations rounded. Apical pit remaining open.

Dimension of holotype (female): Length 12.3, width
10.1. height 5.0 mm; dimensions of illustrated paratype
(male); length 8.4, width 6.5, height 3.0 mm.

External anatomy (figures 4-7, 9): Neck long, wide,
dorso-ventrally compressed, lateral edges acutely angu-
late (except left edge deeply grooved in male). Trans-
verse furrow extending laterally above mouth, delimiting
the ventrally positioned oral lappets. E\'es lacking, ce-
phalic tentacles posteriorly directed, equal and relatively
short and thin in females (contracted state); left tentacle
of male enormously distended, bearing a deep sperm
groove dorsally, which is continuous with deep groove
on left edge of neck. Females lack groo\e on left edge
of neck.

Mantle cavity deep, extending two-thirds the length
of shell muscle on left side. Ctenidium bipectinate, af-
ferent membrane lacking throughout its length, efferent
axis arising at posterior of mantle ca\ it\ on left; free tip
of gill separating above base of neck, its efferent axis
massive, extending well anterior of head; gill filaments
overlying head, greatly elongate, decreasing in length
toward tip.

Mantle margin with fine papillae corresponding to
radial ribs. Outline of foot rounded; anterior edge of foot
with furrow marking opening of pedal gland. Epipodial
ridge encircling foot, extending forw ard on both sides to
join with neck edges; short, contracted epipodial ten-
tacles evenly spaced along ridge, becoming smaller an-
teriorly, not extending anteriorly beyond position of shell
muscle. Operculum (figure 9) ver>- thin, transparent,
multispiral, with rapidK enlarging final whorl, edge
frayed, shed in some large females (largest operculum
about 4 mm diameter).

In dorsal view of detached animal, shell muscle arms
very broad, except posteriorly, where reaching one-fifth
the maximum width: anterior terminations rounded;
mantle skirt thin, show ing posteriormost extent and out-
line of ctenidium; pericardium \ isible as dark structure
posterior to gill; gonad and pallial gonoducts large, over-
King digesti\e gland, occupying posterior dorsal area
next to right arm of shell muscle (figure 4).

Radula (figures 15, 16) rhipidoglossate, rachidian and

Page 80

THE NAUTILUS, Vol. 104, No. 3

Figures 1-10. Synunetjomphalus regulari, new species, trom .\lice Springs vents, Mariana Back Arc Basin, Alvin dive 184,3,
3,640 m. Anterior at top in dorsal and ventral views. 1-6. Holotype (female), LACM 2432, shell length 12.3 mm. 1 Shell e.xtenor_
2. Shell interior 3. Left side of shell. 4. Dorsal view of detached bod> .5. Ventral view of detached body. 6. Left la era view ot
detached body. 7-!0. Paratype (male), LACM 2433, shell length 8 4 mm. 7. Dorsal view of detached body. 8. Shell exterior. 9.
Ventral view, animal attached to shell, showing opercuhim on edge. 10. Left side of shell.

four pairs of lateral teeth of similar morphology, mar-
ginal teeth numerous, cusj-. rows of all teeth forming
circular arc. Base of rachidian tooth broad, overhanging
cusp moderately long, tapered to acute tip. First lateral

tooth slightly less prominent than rachidian tooth, inner
base behind' that of rachidian tooth. Second, third and
fourth lateral teeth similar to each other, their innermost
bases behind the base of adjacent lateral teeth; lengths

]. H. McLean, 1990

Page 81

Figures 11-14.
1 1. Dorsal view
= 100 fim.

Symmetromphalus regularis new species. SEM views of ju\enile paratvpe, LACM 2433. shell length 3.5 mm.
12. Oblique, left lateral view. 13. Protoconch and early sculpture, scale bar = 200 tim. 14. Protoconch, scale bar

of shafts and overhanging cusps increasing in length out-
wardly. Fourth lateral tooth larger than third, its outer
edge sharply serrate, its lowermost serration most prom-
inent. Inner marginal teeth with long, broad shafts, cusp
edges deepK serrate; shafts of outer marginal teeth in-
completely separated.

Type locality: Alice Springs vents, Mariana Back-Arc
Basin (18°12.6'N, 144°42.4'E), 3,640 m. The limpets oc-
cur in dense aggregations on the walls of the vents (figure
17). From the photograph it is evident that the limpets
are oriented randomly, filling all space on the substrate,
but not stacked.

Type material: 27 specimens from t\pe localitv, Alvin
dive 1843, 4 May 1987. Holotype LACM 2432, io para-
types LACM 2433, 10 paratypes USN'M 784763, 6 para-
types MNHN. All specimens have undamaged perios-

traca, free of biogenic or mineral encrustations. Males
are represented by six specimens only, of which the
smallest (with broken shell) is approximate!) .5 mm in
length. Twelve specimens under 5 mm in length are too
small to sex w ithout sectioning.

DISCUSSION

Higher Classification

The affinities and the higher classification of the N'eom-
phalacea are yet to be fully resolved and are likely to
remain controversial for .some time. Fretter et al. (1981)
aflirined that Seoniphalus is a highly derived archaeo-
gastropod, but could not relate it to other known living
groups. Waren and Bouchet (1989) placed the newK'
described family Peltospiridae McLean, 1989, in the

Page 82

THE NAUTILUS, Vol. 104, No. 3

Figures 15, 16. Symnictroiuphdhis rcgiiluns iitn\ species. .SEN! views of radula of paratype. 15. Full width of ribbon, showing
rachidian, four pairs of lateral teeth and numerous marginal teeth, scale bar = 40 nm. 16. Enlarged view of overhanging cusps of
rachidiaii, laterals and marginals, scale bar = 20 nm.

Neomphaiacea, whereas McLean {1989a), Fretter (1989),
and Haszprunar ( 1988a, b, as hot- vent group A) separated
two superfamilies: Neomphaiacea and Peltospiracea.
Shared characters of both superfamilies include the mo-
notocardian heart, bipectinate ctenidia that lack bursi-
cles, oesophageal features, statocysts with statoliths, and
radular similarity. In having the left kidney only and in
lacking ctenidial bursicles both groups were placed out-
side the \'etigastropoda (superfamilies Scissurellacea,
Pleurotomariacea, Fissurellacea, Haliotacea, Trochacea,

and Lepetodrilacea) by Salvini-Plawen and Haszprunar
(1987) and by Haszprunar (1988a, b). Both groups were
regarded as generally more primitive than the Vetigas-
tropoda by Haszprunar.

The main argument for separation of Neomphaiacea
and Peltospiracea concerns the striking differences in
external features that are related to feeding modes: in
Neomphaiacea the neck is long and dorso-ventrally com-
pressed; transverse furrows lead from the recessed mouth
to protruding lappets that are ventral to the cephalic

Figure 17. Symmcdomplmlus ref^ularis new species. In situ view of limpets on basalt boulders in path of effluent at Alice Springs,
Mariana Back Arc Basin, 3,640 m. The largest limpets may exceed 14 mm in length Photo courtesy S Ohta

J. H. McLean, 1990

Page 83

tentacles (see Waren & Bouchet, 1989: fig. 23 for Cya-
thermia), and there is a notch for dorsal access to the
mouth from the food groove (well-developed only in
Neomphalus), the bipectinate gill is h\pertrophied, the
gill filaments elongate and separated for filter feeding in
combination with grazing. In contrast, the Peltospiracea
are known by the descriptive appellation of "tapersnouts,'
which was first used by McLean (1985) prior to their
formal description, because of their long, tapered snouts.
The tapered snout was correlated by Fretter (1989) with
a well-developed, protrusible subradular organ, enabling
the snout to project at great length.

The Peltospiridae include both limpet-shaped and
coiled members. Two important papers on anatomy of
peltospirids have been published, that of Fretter (1989)
on anatomy of the limpets and the subsequent paper of
Haszprunar (1989) on the anatom\ of the coiled Melano-
drymia. UnfortunateK Haszprunar did not have benefit
of access to the manuscript of Fretter (1989), so that
comparisons could not be made. Melanodrymia is atyp-
ical of peltospirids in several respects: having both the
left and right tentacles modified for copulation (unlike
the peltospirid limpets or other coiled peltospirids), and
lacking skeletal rods in the ctenidium. It may be that
Melanodrymia is not a true peltospirid, although Hasz-
prunar elected not to establish a family for it.

Anatomical comparisons between all supposed pelto-
spirids are needed. The limpet Hirtopelta McLean, 1989a,
lacks a tapered snout and represents a genus not strictly
peltospirid. Another unresolved problem has been noted:
there are two different protoconch tvpes (net sculpture
and longitudinallv ribbed) both in limpet genera and
coiled genera (McLean, 1989a; Waren & Bouchet, 1989).

Knowledge of the internal anatomv' of Cyathermia is
also needed. Because it is regularly coiled, it seems ev-
ident that Cyathermia is less derived and probably a
better representation of neomphalacean anatomy than
Neomphalus, although the Cyathermiidae seem to have
more complex reproductive modifications in having cirri
at the tip of the copulatory appendage. Symmetrom-
phalus. the new genus described here, is less derived
than Seomphalus. for the reason that its symmetry is
typical of all other prosobranch limpets, its torsion not
carried through an additional 90 to place its mantle cav-
ity on the left, as in Seomphalus. S'eomphalus is also
more derived in having a well-defined food groove and
a gill that is larger and thereby more effective than that
of Symmetromphalus.

Radular similarities between Neomphalacea and Pel-
tospiracea need not inilicate close affinity. Hickman (1983)
first discussed both radular types, and in 1984 reported
that the radula of Melanodrymia yvas similar to that of
Neomphalus and that both could represent an "unspe-
cialized grade of rhipidoglossate radular evolution"
Haszprunar (1989) agreed that radular similarities could
be '"plesioniorphic and should not be overemphasized in
tracing phylogenetic relationships. ' A similar case of rad-
ular uniformity is known in the earliest ontogenetic stages
of most trochaceans (Waren, 1990).

One can unite the superfamilies Neomphalacea and
Peltospiracea within a suborder Neomphalina based on
such shared characters as the similarity of the unspe-
cialized radulae, lack of nacre, and lack of ctenidial
bursicles, but these are plesioniorphic, grade defining
characters. It is difficult to identify apomorphic char-
acters to define such a suborder. We are left yvith negative
characters that suffice to remove both superfamilies from
other y\ ell-defined suborders. In spite of the present dif-
ficulties in justifying a suborder Neomphalina within a
rigorous cladistic frameyvork, I expect that the original
hy pothesis of Waren and Bouchet (common ancestry for
Neomphalidae and Peltospiridae) will eventually be ac-
cepted.

An alternative view of the affinity of Neomphalus was
given by Sitnikova and Starobogatov (1983), in a short,
unillustrated paper in which they- placed Neomphalus
in their neyv suborder "Neomphaloidei" [sic] in the order
N'ivipariformes Sitnikova and Starobogatov, 1982. A
translation of the original Russian has been obtained,
courtesy David R. Lindberg. The radula of Neomphalus
was said to lack a lateromarginal plate and to have mar-
ginal teeth that are not distributed in groups of small
secondary teeth as in rhipidoglossate radulae of trochid,
turbinid, and neritid species. Marginal teeth of Neom-
phalus yvere said to be more similar to the marginal teeth
in the architaenioglossate radula, particularly the genus
Leonia in Pomatiidae, despite the fact that there are
only tyvo pairs of marginal teeth in Leonia. Other shared
characters cited yvere elongate mantle cavities and looped
pallial gonoducts.

Waren and Bouchet ( 1989) dismissed the Sitnikova and
Starobogatov phylogeny of Neomphalus as not to be
taken seriousl) in the absence of detailed evidence, and
objected to the placement of Neomphalus among the
Mesogastropoda. I agree that a more convincing expo-
sition of the theory needs to be presented. The radular
argument seems irrelevant to me: why should the neom-
phalacean radula be structured like that of other knoyvn
rhipidoglossate groups? Nothing is said to falsify- the in-
terpretation that it is a relatively unspecialized rhipi-
doglossate radula. Recently, Golikov and Starobogatov
(1988) introduced 36 new prosobranch suborders while
maintaining the order Vivipariformes yvith suborders
Neomphaloidei, Viviparoidei, and N'alvatoidei. This was
done yvithout knoyvledge of the later introduction of Pel-
tospiracea (McLean, 1989a; Waren & Bouchet, 1989;
Fretter, 1989) and of recent work on Valvatidae (Rath,
1988), yvhich resulted in the placement of N'alvatacea in
the subclass Heterobranchia by Ponder and \\'aren (1988).

An article in Japanese entitled "Neyv archaeogastropod
superfamily Neomphalacea" by Nakamura (1986) is not
to be taken as a proposal of a homonym for the super-
family ; rather it is evidently a review note intended for
Japanese readers.

Feeding Biology

Haszprunar (1988b) suggested that "Neomphalus itself
probably does not feed by filter-feeding alone, but pos-

Page 84

THE NAUTILUS, Vol. 104, No. 3

sibly by symbiotic chemoautotrophic bacteria and/or by
grazing bacterial films like some other molluscs of the
hydrothermal vents. This is indicated bv its radula, which
is not like those of typical Biter feeders. ..." Original
reports on Neomphaltts of McLean (1981) and Fretter
et al. (1981) made it clear that part of its nutrition is
deri\ed from grazing, particularly in the younger stages.
Symbiotic chemoautotrophic bacteria are associated with
most bivalves in the hydrothermal-vent community, but
the onl\ \ent-associated gastropod for which this rela-
tionship is known is Alvinoconcha hessleri, as reported
by Stein et al. (1988). Stein (personal communication)
has informed me that other vent limpets have been sub-
jected to biochemical assay (ribulose-l,5-diphosphate
carbo.xylase) for chemoautotrophic s\nibionts, but the
negative results were not published. There is, however,
a report by de Burgh and Singla (1984) of bacterial
colonization of the gill surface and direct endocytosis of
the bacteria in the limpet subsecjuently described as Le-
petodrilus jncensis McLean, 1988.

Haszprunar's comment that the radula of Neomphalus
is not like that of typical filter-feeders is not relevant,
because the radulae of filter feeding gastropods in such
superfamilies as Trochacea, Cerithiacea, and Calyptrae-
acea are subject to the phylogenetic constraints of the
radular plans typical of each group. A typical filter-
feeding radula can therefore not be defined. The radula
of a filter-feeding gastropod functions primarily to rake
in a food string, for which many possible morphologies
are suitable.

Fossil Record

A direct fossil record for any neomphalacean or pelto-
spiricean shell morphology remains to be established. In
my earlier assessment of Neomphalus (McLean, 1981),
I suggested that there may be a link between Neompha-
lacea and the Paleozoic Euomphalacea, which I had
(somewhat rashly) emphasized by placing both in a
therein proposed suborder Euomphalina. The thrust of
my argument was as follow s: given that euomphalaceans
have been regarded as immobile and therefore potential
filter-feeders (references in McLean, 1981), a gill like
that of Neomphalacea could have provided the mech-
anism by which filter-feeding was possible in Paleozoic
euomphalaceans.

Although most subsequent authors have ignored my
functional argument, Runnegar (1983) took notice of it.
He did "not wish to disagree with an\ of this," but had
difficulty with the resulting classificatit)n. Batten (1984)
found no similarities in shell structure between Neom-
phalacea and Paleozoic Euomphalacea. Bandel (1988)
removed from Euomphalacea all Mesozoic genera men-
tioned by McLean (1981) as possible links between the
two groups. While the latter two authors have found no
e^ idence supporting the connection, it can still be argued
that a connection to Paleozoic euomphalaceans (or pos-
sible related iiroups) through unknown intermediate steps
remains possible. Now that Cyathermia, as well as the

entire peltospiracean complex, is known, it may be easier
to conceive of a connection leading to other li\ing genera.

Sitnikova and Starobogatov (1983) stated that a con-
nection between Neon^phalus and eumphalaceans was
falsified because Euomphalacea had paired gills (on the
basis of the spiral keel in some euomphalacean genera),
but that rather dogmatic assumption is not generally
accepted and to me seems poorly founded and unlikely.
The shell of Ctjathermia has a deep sinus in the outer
lip (see Waren & Bouchet, 1989: figs. 6, 7), which is
undoubtedly related to projection of the single bipecti-
nate gill. This evidence suggests to me that a hypertro-
phied single gill like that of Neomphalacea would better
correlate with spiral keels or sinuses in the lips of euom-
phalaceans (see McLean, 1981; fig. 13) than would paired
gills.

The coiled genera Cyathermia and Lacunoides dem-
onstrate that the typical neomphalacean gill and mouth
w ith dorsal access to ctenidial filaments can function in
mature, coiled snails. These coiled snails are mobile, but
they are also smaller, of a size comparable to the juveniles
of Neomphalus and Symmetromphalus. We have yet to
discover a larger, coiled member of the Neomphalacea,
but there is no reason to assume that it could not function
as a sedimentary filter feeder. However, we are not likely
to find such a member of Neomphalacea in the h\dro-
thermal-vent habitat, as it would be more prone to shell
crushing by the brachyuran predators in the hydrother-
mal environment.

Now that we have recognized major radiations com-
prising the superfamilies Neomphalacea and Peltospi-
racea, as well as the Lepetodrilacea (see McLean, 1988;
Fretter, 1988), which superfamily is not discussed here,
I continue to believe it likeK that these groups must have
had a fossil record in the Paleozoic and early Mesozoic,
the time at which all living archaeogastropod superfam-
ilies diverged (more detailed discussion in McLean, 1981,
1985, 1988, 1989a, b). There are numerous extinct gas-
tropod clades of the Paleozoic and Mesozoic, which are
assumed to have been rhipidoglossate archaeogastropods,
for which the anatomical plan remains conjectural (see
Knight et al., 1960). The enormously plastic Peltospi-
racea and the newly expanded Neomphalacea have only
been introduced into the literature for slightly over one
year, hardly enough time for paleontologists with inter-
ests in Paleozoic and Mesozoic faunas to have searched
for connecting links.

BlOGEOGRAPHlC IMPLICATIONS

The Mariana Back Arc Basin vents are isolated from all
other known Indrothermal sites, \et the\- contain some
launal elements in common with those of other sites, in
addition to faimal elements found nowhere else. Only
one moUusk, the lepetodrilacean limpet Lepetodritus ele-
vatus McLean, 1988, occurs widely at vents on the Ga-
lapagos Rift and at all Indrothermal vent-fields on the
East Pacific Rise as well as at the Mariana vents (McLean,
unpublished). There is also a faunal connection of the

J. H. McLean, 1990

Page 85

Mariana vents to the vents of the Mid-Atlantic Ridge:
Pseitdorinmla McLean, 1989, has an undescribed con-
gener at the Mid-Atlantic Ridge (McLean, in prepara-
tion). Hessler et al. (1988) suggested that hvdrothermal
vents associated with past spreading centers are likeK to
account for these wideK disjunct distributions. Tuiuii-
cliffe (1989) discussed the vicariant events that shaped
the present distributions of hydrothermal-vent faunas
shared b\ the East Pacific Rise and the Juan de Fuca/
Gorda Ridge S)Stems. The \icariant events that would
allow interchange between the eastern Pacific ridge s\s-
tems and the Mariana Back Arc Basin remain to be
treated in the literature. Vast amounts of geologic time
must surely be involved, in view of the slow, step-by-
step dispersal of vent archaeogastropods that is necessi-
tated by their lack of planktotrophic dispersal stages (for
review see Lutz, 1988).

ACKNOWLEDGEMENTS

Specimens of Symmetromphalus regularis were for-
warded by Robert Hessler of Scripps Institution of
Oceanography. I thank Clif Coney (LACM) for oper-
ating the SEM at the Center for Electron Microscopy
and Microanalysis, Universit) of Southern California.
Pictures of the preserved specimens are the work of
Bertram C. Draper, LACM volunteer. I thank S. Ohta
for the use of figure 17. Helpful commentary on the
manuscript was provided by Gerhard Haszprunar and
Anders Waren and by an anon\mous reviewer. I take
full responsibility for the opinions expressed here and
the decisions as to the need for the new supraspecific
taxa.

LITERATURE CITED

Bandel, K. 1988, Reprasentieren die Euoniphaioidea eine
naturlich Einheit der Gastropoden? Mitteilungen des Geo-
logische-Palaontologischen Institutes der Universitat
Hamburg 67:1-33.

Batten, R. L. 1984. Shell structure of the Galapagos rift limpet
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cle scars and insertions. American Museum Novitates no.
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Bieler, R. 1990. Haszprunar s "dado-evolutionary" classifi-
cation of the Gastropoda — a critique Malacologia 31(2):
371-380.

de Burgh, M. E. and C. L. Singla. 1984. Bacterial colonization
and endocytosis on the gill of a new limpet species from
a hydrothermal vent. Marine Biology 84:1-6

Fretter, \'. 1988. New archaeogastropod limpets from hv-
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Fretter, \', 1989. The anatonn of some new archaeogastropod
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Fretter, V., A. Graham, and J H, McLean. 1981. The anat-
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(;(>liko\. A, .\. atid V 1. Slarohogatov. 1988. Problems of
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THE NAUTILUS 104(3):87-91, 1990

Page 87

Shell Dissolution Rate in Freshwater Pulmonate Snails:
Influence of Periostracum and Water Chemistry

R. Douglas Hunter

Department of Biological Sciences

Oakland University

Rochester, MI 48309-4401, USA

ABSTRACT

The size-specific rate of shell dissolution was measured in situ
in three Michigan lakes that differed in pH and calcium con-
centration using shells of two species of freshwater pulmonate
snails. Physella integra (Haldeman 1S41 ) and Helisoma anceps
(Menke 1830). Lack of a periostracum resulted in significantK
higher rates of dissolution as did exposure to lake water with
either low pH and/or low [Ca-*]. Three-factor ANOV'A indi-
cated significant effects for periostracum condition and site as
well as significant two and three-way interactions.

For H. anceps (but not P. integra) the periostracum appears
to greatly reduce the rate of shell dissolution hence ma\' serve
to reduce shell damage in acid waters. .Adverse water chemistry
(low pH and or low Ca'*) has a much greater effect on shell
dissolution across species (CD = 81 S) than does presence or
absence of periostracum (CD = 4'^).

Shell dissolution response to water chemistry as well as the
degree of periostracum protection differs between these two
species of snails. Models of lake acidification involving either
Ca-* flux and pool sizes or mollusk population survival may
need to consider such differences.

Key words: .-Acidification; pH; calcium; snail; shell; perios-
tracum; dissolution; freshwater.

INTRODUCTION

Freshwater mollusks are known to be more sensitive to
acidification of their habitat than other benthic groups
(Okland & Okland, 1986). Although shell erosion of adult
snails and certain physiological processes are influenced
by exposure to acid waters, the egg and juvenile stages
are most severely affected (Zischke et ai, 1983; Rooke
& Mackie, 1984; Burton e^ a/., 1985; Hunter, 1988, 1990).
This sensitivity of early developmental stages is also ob-
served in waters of low calcium concentration due to the
importance of calcium in normal molluscan physiology
(Rooke & Mackie, 1984; Hunter, 1990). It is now evident
that the disappearance of mollusk populations from lakes
or streams affected by acidic deposition is due to re-
cruitment failure as a result of developmental arrest and
poor juvenile survival (Hunter, 1988, 1990; Shaw &
Mackie, 1989). In contrast to eggs and juveniles, adult
snails are relatively resistant to short-term exposure to

moderate (pH 5-6) levels of acidity (Servos & Mackie,
1986); however they commonly develop shell damage,
such as pitting, as a result. Longer term exposure at
slightly higher (but still subneutral) pH may also result
in shell pitting. Evidence of shell dissolution in adult
snails may therefore provide an early indication that the
population is at risk from recruitment failure (Hunter,
1988). .■\lthough it might appear that one could make
such a determination based on measurement of ambient
physico-chemical parameters (e.g.. pH, [Ca'*], dissolv-
ed inorganic carbon, etc.), such measures are indirect
indicators of stress on an ac}uatic mollusk population
hence, at best, are useful only as general indicators. Ev-
idence cited in Okland and Okland (1986) suggests there
is a wide range of tolerances to high [H*] among species
of freshwater mollusks. This is likeK compounded by
interpopulation variation in tolerance, making it difficult
to predict at precisely what pH level one would e.xpect
a particular species-population to begin showing stress.
Results that examine the interaction of pH and [Ca-*]
in terms of adverse effects on fecundity, dexelopment,
and juvenile survival in a pulmonate snail have been
reported elsewhere (Hunter, 1990). The purpose of this
study was to measure the rate of shell dissolution using
shells of two species of freshwater pulmonate snails, some
v\ith periostracum (proteinaceous outer shell la\ er), some
w ithout it, in lakes with different pH and [Ca-*] condi-
tions. Interspecific differences, influence of the perios-
tracum, and lake differences insofar as they might mod-
iiy the rate of shell dissolution were of particular interest.

MATERIALS AND METHODS

The shells of two species of freshwater pulmonate snails
were used in this study. Shells of Physelh ("Physa")
integra and Helisoma anceps originated from Douglas
Lake, Cheboygan Co., Michigan, I'S.A. Empt\ shells from
adult-size animals that had died w ithin the past 24 hours
were obtained from aquaria of concurrent culturing ex-
periments. Any remaining debris inside these shells was
removed by a jet of distilled water into the aperture after
w Inch the shells were air-dried. Such shells had a fully
intact periostracum. Living snails were not used because

Page 88

THE NAUTILUS, Vol. 104, No. 3

they deposit shell even while previously secreted CaCOa
is undergoing dissolution. Hence the use of gravimetric
methods to measure rates of loss would be confounded
by simultaneous additions to and removal from the shell
mass.

Shells w ithout a periostracum were obtained from as-
sorted shells (probabK <5 years old) that had washed
up above water level where the periostracum was lost
by natural (aerial) weathering. These latter shells con-
trasted markedly with those having an intact periostra-
cum b\ lacking most of the characteristic color and glossy
sheen of the shells of living snails, instead having a matte,
chalk) white appearance. Shells that were eroded, pitted,
or strongly discolored, were avoided.

The apertures of both kinds of shells were completely
sealed with silicone aquarium sealer so as to prevent
erosion of shell material from the inner surface (nacreous
layer) of the shells. This assured that any shell loss by
dissolution would be from the outer surfaces of the shell
onK. Shells were then dried at 10.5 ± 5 °C to a constant
weight and placed into numbered mesh bags ("bridal
veil" of 1 mm- mesh size). The bags were then enclosed
in styrene plastic boxes with screened tops and bottoms
and attached to stakes securely driven into the bottoms
of three selected lakes. The lakes in whicli the shells were
submerged are identified below along w ith the means of
three calcium and pH measurements (taken near shore
at 0.5 m). These study sites were all located on protected
(windward) shores.

1. Douglas Lake, Cheboygan Co., MI: high calcium
(35.4 mg Ca^VD; high pH (8.59).

2. Vincent Lake, Cheboygan Co., MI: low calcium (3.5
mg Ca-+/L); high pH (7.78).

3. Lake Nita, Alger Co., MI: low calcium (3.0 mg Ca-*/
L); low pH (5.47).

No mollusks are presently found in either Vincent or
Nita; however, H. anceps (with pitted shells) occurred
in Vincent Lake up to a few years ago.

The experimental design was factorial with three sites,
two species, and two periostracum conditions giving 3
X 2 X 2 = 12 treatments. Each treatment involved ten
replicate shells or 120 total shells. Shells remained in situ
at 0.25-0.5 m depth for 42 days at Douglas Lake and
Vincent Lake and 45 days at Lake Nita, after w hich they
were removed, dried, and weighed. Change in shell mass
was computed from weights before and after dr\ing,
then (assuming linear weight loss) converted to a rate by
dividing by the number of days. Since larger shells lose
more CaC03 per unit time than smaller shells, small
differences in starting shell size among treatments were
compensated for b> dividing dissolution rate b> shell size
(maximum shell dimension), hence the data are ex-
pressed as bi/.c-sppcific dissolution rate which is ;ug CaCO,,
dissoKed per tma shell dimension day.

Differences am. mx treatments were evaluated using
one and three factor .WOVA and Fishers Protected Least
Significani iWev^.ncr Procedure (PLSD). The latter is a
two-stage proc\"J.urf. w lere an overall test of significance

(standard F-test) is followed by pairwise comparisons if
the F-test is significant at the chosen alpha level (Koop-
mans, 1987).

RESULTS

Figure 1 shows mean size-specific dissolution rate for all
twelve treatment groups. Results of a one-factor ANOVA
indicated that there were significant differences among
treatments (F,,, i,,,, = 116.99, P < 0.0001). Treatment
histograms having a common letter are not significantly
different from each other by Fishers PLSD (a = 0.05).
These data indicate that there are substantial site and
periostracum effects; e.g., shell dissolution is minimal at
Douglas Lake (<3 /ig/'(mmday) for either species
whether the periostracum is present or absent. In con-
trast, the Vincent Lake site (high pH, low [Ca-^]) pro-
duced dissolution rates that were intermediate, ranging
from 9.7 ^g/(mm-day) for H. anceps shells with peri-
ostracum to27.2^g/(mmda\ ) for H. anceps shells with-
out periostracum. The highest rates of shell dissolution
occurred at Lake Nita (low pH, low [Ca-*]) ranging from
17.7 ^g/(mm-day) for H. anceps with periostracum to
58.7 /ig/(mmday) for H. anceps without periostracum.
Dissolution rates for P. integra shells with periostracum
were higher than the above rates for H. anceps. Physella
integra shells with periostracum at Vincent Lake lost
mass at 15.1 ^g/(mmdaN ) while those at Lake Nita lost
mass at 36.7 /jg/(mmday). Without periostracum, how-
ever, P. integra rates were lower than those for H. an-
ceps: 19.8 /xg/(mmday) at Vincent Lake and 39.7 ng/
(mm -day) at Lake Nita.

It can also be seen from figure 1 that absence of a
periostracum in H. anceps greatly increased the shell
dissolution rate of that species, however, in P. integra
the dissolution rate was only slightly increased by lack
of a periostracum. and the difference was not significant.
In H. anceps the lack of a periostracum resulted in a
dissolution rate that is over two (at N'incent Lake) or
three times greater (at Lake Nita) than at Douglas Lake.

The degree to which size-specific dissolution rate is
influenced by the three main effects (site, species, peri-
ostracum condition) is expressed in table 1. which gives
the results of a three-factor ANOVA (SPSS-X). Since the
data were neither normally distributed nor were the
variances of the treatment means equal, a square root
transformation was used. Both site and periostracum con-
dition had significant effects on size-specific dissolution
rate; for site, F. „):,. = 712.84 (P < 0.001) and for peri-
ostracum condition, F,i ,03) = 63.92 (P < 0.001). There
was no significant effect for species; i.e.. P. integra and
//. anceps shells had similar rates of dissolution when
considered as species groups across the three sites. The
size-specific rate of dissolution was influenced more by
site differences than b\ presence or absence of a perios-
tracum. The coefficient of determination for site = 81%
whereas that for periostracum condition = 4%.

Table 1 also indicates that there are significant two-
aiid three-wav interactions between the main effects.

R D. Hunter, 1990

Page 89

E
E

50-

S^ 30

■^ 20 ■

o
b

_o_ g

DL DL VL VL LN LN
+ - + - + -

Helisoma onceps

DL DL VL VL LN LN

+ - + - + -

Physella Integra

Figure 1. Size specific shell dissokitioii rates (x ± SE) lor P.
Integra and H. anceps with ( + ) and without ( — ) periostracum
at three lakes: DL = high pH, high Ca-* site; VL = high pH,
low Ca-* site; LN = low pH, low Ca-* site. Histograms with
the same letter over them are not siguificantK different bv
Fishers PLSD (a = 0.05). N = 10 for all treatments.

Specifically, the shell dissolution rate of either species at
a particular site is dependent on periostracum condition.
Assuming a constant dissolution rate at summer lake
surface temperatures, one can calculate the number of
days required for dissolution losses to equal the entire
mass of an average size shell. Using a mean dry shell
weight of 70.9 mg for P. Integra and 77.7 mg for H.
anceps, it would take 8,273 days and 2,472 days, re-
spectively, for a typical adult-size shell, with intact peri-
ostracum at Douglas Lake, to completely dissolve. At
Vincent Lake, these figures are lowered to 424 days for
P. Integra and 768 da\s for H. anceps (both with peri-
ostracum), and at Lake Nita they are further lowered to
178 days for P. Integra and 368 days for H. anceps. The
shortest time to complete dissolution would be 118 days
for an H. anceps shell, without periostracum, in Lake
Nita.

DISCUSSION

The results presented herein suggest that the periostra-
cum of Physella Integra shells offers little protection
against shell dissolution due either to low ambient [Ca-*]
or to low pH. For Helisoma anceps, however, the pres-
ence of an intact periostracum substantialK reduces shell
loss in lakes of low [Ca-*]. For example, in Vincent Lake
(low [Ca-*], high pH), shell loss was reduced by 64.6%
when compared to shells without a periostracum. Simi-
larly, at an acid lake (Lake Nita) where both low [Ca-*]
and low pH occurred, the presence of a periostracum
reduced shell dissolution by 69.8'^(:. Hence in H. anceps
the presence of an intact periostracum may reduce shell
damage in slightly acid waters.

Table 1 . Results of three factor ANO\'A on size-specific shell
dissolution rate data tor Physella integra and Helisoma anceps
at three different lakes and with periostracum either present
or al)sent. Data were square root transformed.

Degrees

Mean

Source of \ariation

freedom

square

Main effects

Site

265.60

712.84*

Species

0.00

0 00 ns

Periostracum

23.82

63.92*

Two-way interaction

Site X species

0.71

1.91 ns

Site X periostracum

17.64

47.35*

Species x periostrac\mi

14.49

38.88*

Three-way interaction

Site X species x

periostracum

9.92

26.61*

Error

103

0.37

Total

114

5,78

*P < 0,001; ns = P > 0.05.

The method used to obtain periostracum-free shells
was to select weathered shells from debris above the high-
water line. These w eathered shells had been exposed to
sun, dr\ing, freeze-thaw, etc., for a few months/years.
It is not known if this weathering did more than simply
cause the loss of the periostracum; i.e., does such treat-
ment alter the dissolution rate? If so, the effect is likely
to be small based on the fact that for P. integra there is
no significant difference in dissolution rate between
weathered (= periostracum-free) and unweathered (=
with periostracum) shells at all three sites (see table 1).

The periostracum is the outermost laser of mollusk
shells and is entireK organic, consisting largeK' of con-
chiolin, a quinone-tanned protein (Wilbur, 1964). Below
this layer lies most of the mass of the shell which is
calcium carbonate secreted in a protein matrix.

Most of the references to periostracum function in the
literature are to prosobranchs or bivalves (Wilbur, 1964;
Digby. 1968; Tevesz & Carter, 1980). Fretter and Gra-
ham (1962) suggest that, for prosobranch snails and la-
niellibranchs, the function is to reduce shell erosion. It
is not clear if this is a reference to mechanical abrasion,
chemical dissolution or both. In .some groups, such as
burrowing and boring bivalves, there is a substantial peri-
ostracum that apparently protects against mechanical
abrasion (Morton, 1964; Yonge & Thompson, 1976). Tev-
esz and Carter (1980) suggest that the unionacean peri-
ostracum is one of the most important adaptations of this
group to prevent shell dissolution. A variety of peri-
ostracum functions have been suggested for bivalves,
including minimization of encrusting b\- epizooans, re-
sistance to boring and attack by other predators, in-
creased stabilit) in the substratum, and decreased effect
of substratum scour (Bottjer & Carter, 1980; Wright &
Francis, 1984). .\lthough working w ith h\drothermal vent

Page 90

THE NAUTILUS, Vol. 104, No. 3

bivalves, Hunt (1987) observed that periostraca might,
among other functions, provide protection of the mature
shell from chemical dissolution. In a study of marine
bivalves, Swinehart and Smith (1979:380) suggested that
magnesium and iron in the periostracum could "act as
a defensive buffer against degradation from acidic con-
ditions."

In freshwater pulmonate snails, the periostracum is
relatively thin and generally lacks hair-like projections
that are found in certain bivalve groups. There is little
in tile literature to suggest a function for the periostracum
in this group of snails.

Further evidence that the periostracum provides some
protection against shell erosion is derived from casual
field observations that pulmonates from stressful envi-
ronments often have deeply pitted shells. It is likely that
once a small area of periostracum has become worn away
(usually abraded by mechanical damage) then the ex-
posed underKing shell dissolves more rapidly than un-
affected areas nearby. The result is a pit in the shell that,
in time, may open into a perforation possibly leading to
the death of that individual. Although e.xtensive wear
and pitting is often observed in the umbonal region of
freshwater bivalves, such wear is likely a result of the
physical process of abrasion, rather than of chemical
effects (Hinch & Green, 1988). Bivalve shells, which are
in contact with interstitial water of the substratum over
much of the shell area, are subject to somewhat different
(moderated) physico-chemical conditions than are pul-
monate snails, which are usually located on the surfaces
of stones, vegetation, sediment, etc., hence are more di-
rect!) exposed to lake or stream water conditions. Hinch
and Green (1988) argue that increased shell erosion in
bivalves most likely results from physical etching due to
water turbulence rather than from chemical dissolution.
However, chemical dissolution rates would also be ele-
vated by conditions of water turbulence and should not
be ruled out. The same authors found that bivalve shell
etching was not related to water chemistry (alkalinity
and pH levels) and it may be that the nacroprismatic
shell microstructure of unioiiaceans is substantialK more
resistant to dissolution than that of freshwater pulmo-
nates (Tevesz & Carter, 1980; Hinch & Green, 1988).

It is not surprising that contact by snail shells with
lake water low in calcium or low in both calcium and
pH substantially increases the rate of shell dissolution.
In a laboratory study, whole animal [Ca-*] of Planorbella
trivolvis, after 53 days of exposure to pH 4.9, decreased
16% on a dry weight basis and 14% on a size-specific
basis (Hunter, 1988). In that same study it was reported
that ashed shells (essentially CaC^O.j without the perios-
tracum or any other organic material) lost ClaCO, about
4.6 times faster than did the shells of live animals. One
may envision the shell as a non-living mass of CaCO,
which is in direct contact with and responsive to calcium-
deficient or acid water, despite being a part of a living
mollusk.

What is perhaps unexpected is that there is such a
different response by the shells of the two species in-

volved in this study. Comparing the size-specific disso-
lution rate of shells exposed to X'incent Lake water (low
[C^a-^j, circumneutral pH) with that of shells exposed to
Douglas Lake water (high [Ca-*], slightly alkaline water),
P. Integra showed a 43-fold increase and H. anceps a
6-fold increase in dissolution rate. In other words, P.
Integra shells with intact periostraca were far more sen-
sitive to dissolution-inducing conditions than were shells
of H. anceps. Interestingly, H. anceps shells were the
more sensitive of the two species to the absence of a
periostracum. Thus, P. Integra shells are moderateK sen-
sitive to dissolution-inducing conditions, whether the
periostracum is present or not. In contrast, H. anceps
shells with periostracum are less sensitive to dissolution
than those of P. Integra, but without a periostracum, H.
anceps shells are considerably more sensitive. This study
suggests that the periostracum in some snail species {e.g.,
H. anceps) could act as a deterrant to shell dissolution.
In populations that are in locations subject to gradual
acidification, the life of adults may be prolonged com-
pared to other species {e.g., P. integra).

Clearly, either the paucity of Ca-^ ions in the water
or relatively low pH ma\ result in higher rates of loss of
shell mass in pulmonate snails. Data from this study
indicate that when both conditions occur (which is typ-
ical of acid lakes) that the shell dissolution rate is higher
than it is for lakes having low [Ca-^] and neutral or
alkaline pH. It is not possible from this study to know if
pH and [Ca-*] are acting synergistically; however data
from another study indicate that such is not the case,
i.e., effects of low [Ca-*] and low pH on growth and
fecundit) of snails reared in the lab are no more than
additive (Hunter, 1990).

This study demonstrates that degree of periostracum
protection and shell dissolution rates may differ signifi-
cantly between species, hence, CaCOj loss cannot be
assumed to be identical for all freshwater snails. Such
considerations are of potential interest in the modeling
of lake acidification processes either in terms of the dis-
appearance of specific molluscan taxa from the benthos
in a regime of continual pH and alkalinit\ reduction or
calcium release by biota to free ion pools.

ACKNOWLEDGEMENTS

I would like to thank the Oakland I'niversity Research
Committee for the Faculty Research Fellowship that
enabled me to work at the I'niversitN of Michigan Bio-
logical Station in Summer, 1986, and the staff at UMBS,
especially Bob Vande Kopple, for their cooperation and
expert assistance. Thanks are also due to Mary Coffey
(OU Mathematics), who helped with the statistical meth-
ods.

LITERATURE CITED

Bottjer. D. J. ainl J. G, Charter, 1980. Functional and pliyio-
geiietic signilicanee ol prdjctlint; pfriostiucai structures in

R. D. Hunter, 1990

Page 91

tile BivaKia (Mollusca). Journal t)f Paleontolog\ 5-1:200-
216,

Burton, T. M,, H, M. Stanford, and J W .Mien. 1985. Acid-
ification effects on stream biota and organic matter pro-
cessing. Canadian Journal of Fisheries and .Aquatic Science
42:669-675.

Digby, P. S B. 196S The mechanism of calcification in the
molluscan shell. In: Fretter, \'. (ed.). Studies in the struc-
ture, physiologN , and ecolog\ of molluscs. .\cai!emic Press,
New York, p. 93-107.

Fretter, V. and A. Graham. 1962. British prosobranch mol-
luscs. Ray Society, London. 755 p.

Hinch, S. G. and R. H. Green. 1988. Shell etching on clams
from low-alkalinity Ontario lakes: a physical or chemical
process? Canadian Journal of Fisheries and Aquatic Sci-
ence 45:2110-2113.

Hunt, S, 1987. .^mino acid composition of periostracal pro-
teins from molluscs living in the \ icinit\ ot deep sea hy-
drothermal \ents. Comparati\e Biochemistry and Physi-
ology 886:1013-1022.

Hunter, R. D. 1988. Effects of acid water on shells, embryos,
and juyenile survival of Planorbella trivolvis (Gastropoda:
Pulmonata): a laboratory stud\ Journal of Freshwater
Ecology 4:315-327.

Hunter, R D. 1990 Effects of low pH and low calcium
concentration on the puhnonate snail. Planorbella trivol-
vis: a laborator\' study. Canadian Journal of Zoology 68:
1578-1583.

Koopmans, L. H. 1987. Introduction to contemporary statis-
tical methods, 2nd ed. Duxbury Press, Boston, MA.

Morton, J. E. 1964. Locomotion. In: Wilbur, K. M. and C.
M. Yonge (eds.). Physiology of Mollusca, Vol. I. Academic
Press, New York, p. 383-423.

Okland, J, and K. A. Okland 1986 The effects of acid de-
position on benthic animals in lakes and streams. Exper-
ientia 42:471-486.

Rooke, J B and (; L Mackie. 1984. Growth and production
of three species of molluscs in six low alkalinit) lakes in
Ontario, Canada Canadian Journal of Zoology 62T474-
1478.

Servos, M. R. and G. L Mackie 1986 The effect of short-
term acidification during spring snowmelt on selected Mol-
lusca in south-central Ontario Canadian Journal of Zo-
ology 64:1690-1695.

Shaw, M. A and G L Mackie. 1989. Reproductive success
of Amnicola limosa (Gastropoda) in low alkalinity lakes
in south-central Ontario, Canadian Journal of Fisheries
and Aquatic Science 46:863-869,

Swinehart, J, H, and K. W, Smith. 1979. Iron and manganese
deposition in the periostraca of several bivalve molluscs.
Biological Bulletin 156:369-381.

Tevesz, M J S and J. G Carter. 1980. Environmental re-
lationships of shell form and structure of unionacean bi-
valves. In: Rhoads, D C. and R. A Lutz (eds.). Skeletal
growth of aquatic organisms. Plenum Press. New York, p.
295-322.

Wilbur, K M. 1964. Shell formation and regeneration In:
Wilbur, K. M. and C. M. Yonge (eds.). Physiology of Mol-
lusca, \'ol, I. .Academic Press, New York, p. 243-282.

Wright, M. M and L. Francis. 1984. Predator deterrance by
flexible shell extensions of the horse mussel. Modiolus mo-
diolus. N'eliger 27:140-142.

Yonge, C. M, and T E. Thompson 1976 Living marine
molluscs. Wm. Collins Sons, Ltd., London. 288 p.

Zischke, J. A., J. W. Arthur, K. J. Nordlie, R. O. Hermanutz,
D. A. Standen, and T. P. Henry. 1983. Acidification
effects on macroinvertebrates and fathead minnows (Pi-
mephales promelas) in outdoor experimental channels.
Water Research 17:47-63.

THE NAUTILUS 104(3):92-95, 1990

Page 92

Effect of Experimentally Induced Shell Damage on
Mortality, Reproduction and Growth in
Helisoma trivolvis (Say, 1816)

Thomas Stahl
David M. Lodge'

Department of Biological Sciences
University of Notre Dame
Notre Dame, IN 46556, USA

ABSTRACT

We conducted a replicated laboratory experiment to test the
potential effect of shell damage (imitating that inflicted by
craxfish) on mortality, reproduction, and shell growth of the
snail Helisoma trivolvis (Say, 1816). During the egg-laying
period of the snail, we removed 0, 2, 4 or 9 mm of shell from
the aperture. For the subsequent 29 days, we monitored snail
egg production, mortality, and shell growth. We predicted that
because of phssiological trade-offs, snails would either repair
their shell and show decreased egg production and mortality
(Hypothesis 1), or forego repair and show high egg production
and early (or high) mortality (Hypothesis 2).

Results were inconsistent with both hypotheses. Only shell
growth differed significantly (p < 0.05) among damage treat-
ments, with growth positively related to damage. Our data do
not conclusiveK refute the trade-off assumption. However, the
results tlo strongly suggest that non-lethal shell damage, like
that indicted by crayfish, is unlikely to affect snail population
growth.

Key words: Helisoma, Orconectes, predation, damage, trade-
off, repair, snails, crayfish.

INTRODUCTION

Snails and their predators have coevolved in ways that
enhance their ability to survive predation and to catch
prey, respectively (Vermeij and Covich, 1978). The im-
portance of predation on marine snails is supported by
an abundance of observations (Norton, 1988; Raffaelli,
1978; Vermeij, 1979, 1982; Vermeij and Covich, 1978)
and experimental evidence (Garrity et ai. 1986). Fresh-
water gastropods, however, have developed far fewer
antipredatory shell features than marine gastropods, per-
haps because of limited minerals in fresh water, insuf-
ficient time for coevolution (due to the relatively young
age of most freshwater bodies), and a lower diversity of
predators in fresh water (Vermeij and Covich, 1978).

' Author to whom correspondence should be addressed.

Recent evidence suggests, though, that freshw ater snails
are readily eaten by both shell-invading predators like
leeches (Brown and Strouse, 1988) and shell-crushing
predators like redear sunfish (Stein ct at.. 1984), pump-
kinseed sunfish (Osenberg and Mittelbach, 1989), and
crayfish (Crowl, 1989; Lodge and Lorman, 1987; Olsen,
1989; Weber and Lodge, 1990). Probably because of their
relatively high feeding rate, e.g., 50-200 Hydrobiaciay-
fish '-day ' (Olsen, 1989), and frequently high densities
(Lodge et ai, 1987), crayfish (Orconectes spp. ) appear
to be particularly potent predators of snails. Field ob-
servations (Weber and Lodge, 1990) and experimental
(Lodge and Lorman, 1987; Lodge, unpublished data)
evidence suggest that crayfish predation influences abun-
dance and species composition of snails in northern Wis-
consin lakes. Indirect effects of predation, such as the
non-lethal shell damage documented extensiveK for ma-
rine snails (Geller, 1990; Raffaelli, 1978; Vermeij, 1982;
Vermeij et ai, 1980; Vale and Rex, 1989; Zipser and
Vermeij, 1980), may have an impact on snail populations
by reducing individual fitness. An experimental test of
this possibility, which has not been previously explored
for freshwater snails, is the topic of this paper.

In laboratory experiments in which freshwater Or-
conectes crayfish prey on snails, predation rate differs
among snail species (A. P. Covich, personal communi-
cation), but intermediate sized shells (6-9 mm) are most
often non-lethally damaged (Olsen, 1989). Smaller snails
are almost always successfully eaten; larger snails, which
have stronger shells, are not handled as easily. In labo-
ratory experiments, Orconectes rusticus (Girard, 1852)
(31-39 mm carapace length) eat about 7% and non-
lethally damage (>1 mm shell aperture peeled awa\ )
about 25% of 60 Helisoma available to single cra\fish in
one night (Olsen 1989). In this paper, we test the impact
on snail mortality, fecundit), and shell growth of ex-
perimentally induced damage that mimicked the cray-
fish-inflicted damage described by Olsen (1989).

Our experiment v\as designed to test two opposing
Inpotheses regarding the effects of non-lethal damage
on reproductively active snails. Both hypotheses are built

T. Stahl and D. Lodge, 1990

Page 93

on the assumption that trade-offs (sensu Tilman, 1989)
exist in the allocation of resources b\' individual snails to
repair, growth and reproduction. The trade-off assump-
tion, e.g., that energy spent on growth decreases energy
available for reproduction, is a critical component in
much ecological and evolutionary thought, to the point
of becoming a paradigm (Tilman, 1989).

Hypothesis 1 is that a damaged snail will divert energy
and nutrients from growth and reproduction to repair
its damaged shell. If this occurs, non-lethal shell damage
b> a predator might limit snail populations even though
the snail is not killed. Hypothesis 2 is that a snail would
respond to non-lethal damage by foregoing repair and
putting all of its energy into reproduction (Kirkwood,
1981 ). This might be the expected result for semelparous
snails, like the Helisoma used in our experiment (see
Boerger, 1975 for description of Helisoma life cycle). If
H\ pothesis 1 is correct, we predicted damaged Helisoma
would exhibit low fecundity, and low or delayed mor-
talit\-. In this case, non-lethal damage might depress snail
populations. If Hypothesis 2 is correct, we predicted
damaged snails would exhibit fecundity similar to un-
damaged snails and early, high mortality rates. In this
case, non-lethal damage would have a negligible effect
on snail populations.

MATERIALS AND METHODS

The experiment was conducted at the University of Notre
Dame Environmental Research Center (L'NDERC) in
the Upper Peninsula of Michigan (46°N, 89°W) during
the latter part (1 June-1 July 1989) of the reproductive
season of H. trivolvis (Boerger, 1975). Adult snails (mean
shell diameter of 24.6 mm, range = 21-29 mm) were
collected from Mullahy and Ward lakes, two small me-
sotrophic lakes on UNDERC propert\ .

This size range of snails was used because it was most
available. While these snails are larger than those most
susceptible to non-lethal damage (Olsen, 1989), we as-
sume response to damage would be similar to that of
species w hose reproductive size is smaller, e.g., Helisoma
campanulata (Say).

Shells were artificially damaged by peeling 0, 2, 4, or
9 mm ring of shell from the aperture with forceps. The
living tissue of all snails was undamaged. There were
seven replicates for each of the four damage treatments.
Each of the 28 experimental units was a shallow fiberglass
tray (30 x 35 x 8.5 cm deep), filled to a depth of 5 cm
with lake water. Snails were randomly assigned to treat-
ments, and trays randomly assigned to a lab bench po-
sition. Trays were maintained with natural lighting from
windows. Temperature fluctuated in the range 14-21 °C.
Each tray contained 10 snails (all with the same degree
of damage) and 2-3 periphyton covered rocks (6-10 cm
diameter) to provide snail food. Food le\el was kept as
constant as possible throughout the experiment by re-
placing water and rocks about once per week (three times
during the experiment). Snail mortalities and egg sacs
were counted every other day. Dead snails were re-

300 n

200-

< y, 1 00 -

~ <

12 16 20 24 2i

0 mm damage
2 mm damage
4 mm damage
9 mm damage

TiMK (I).^^S)

Figure I. Mean (N = 7) cumulative number of eggs per 10
snails as a function of time. No significant difference in total
egg production (day 29) existed among treatments (.\NOV'.>\ p
= 0 40) Figure 2. Mean (N = 7) cumulative deaths per 10
snails as a function of time. Mean for 0 damage treatment is
zero from day 0 through day 8. Differences among treatments
in total mortality (da\ 29) were margitialK significant (.WOX'.^
p = 0.052). For figures 1 and 2, ± 1 SE is indicated for day 29
onl\ .

moved. Egg sacs were collected with a .scalpel from tray
sides, rocks, and shells of snails. Eggs in each egg sac
were counted under a dissecting microscope. Every snail
was measured for new shell growth near the end of the
experiment (24 June).

We tested differences among treatments in egg pro-
duction, mortality, and shell growth with a separate
ANOVA for each response.

Page 94

THE NAUTILUS, Vol. 104, No. 3

1.2

1.0-

^ 0,8i

o
cc
o

1/3

0.6

0.4-

0.2-

0.0-

DAMAGE (mm)

Figure 3. Histogram of mean shell growth (N = 7) ±2 SE for
the four shell damage treatments (ANOVA p < 0.001). The
horizontal bar connects treatments that did not differ (p >
0.05, Tukey's Test).

RESULTS

For all four damage levels, cumulative egg production
increased through about day 12, and began to level off
thereafter as egg-laying ceased (figure 1). No differences
existed among treatments in total eggs laid (ANOVA p
= 0.40 for day 29 data).

Mortality was very low in all treatments through the
egg-laying period, and began to increase in all treatments
after egg-laying ceased (figure 2). On day 29, there was
a marginally significant difference among treatments in
total mortality (ANOVA p = 0.052), but the apparent
rank order of mortality was not correlated to inflicted
damage levels.

Shells in all treatments grew during the experiment,
with growth differing among treatments (ANOVA p <
0.001) and generally positively related to damage level
(figure 3). Regrown shell on damaged snails was very
thin compared to the rest of the shell. This, along witli
the original fracture line, made it easy to measure growth
on damaged snails. On control snails, however, new
growth often blended in with the old shell, rendering
uncertain our growth measurements for the control treat-
ment. Even if control growth data were removed from
consideration, the positive relation between damage and
growth remains for the three damage treatments.

DISCUSSION

Differences in mortality among damage lev els were mar-
ginally significant (p = 0.052), but probabl\- not biolog-
ically meaningful because there is no relationship be-
tween the treatment and the apparent response (figure
2). A lack of relation between damage and mortality is
consistent with the conclusions of Zipser and Vermeij
(1980) that shell damage does not cause mortality in
marine snails. More recentK , though. Geller ( 1990) found
that damaged Nucella, an intertidal snail, have higher
mortality than undamaged snails. Like Helisoma, how-
ever, damaged Nucella have more shell growth, and no
difference in fecundity relative to undamaged snails
(Geller, 1990). In Helisoma, the only response that clear-
ly differed significantly among treatments was growth
(figure 3), which increased with increasing damage. H.
trivolvis damaged most severely regrew their shells the
most (figure 3, p < 0.001), but suffered no decline in
fecundity (figure 1) or any increase in mortality (figure
2). Results were therefore inconsistent with both initial
hypotheses, and apparently inconsistent with the trade-
off assumption underKing both hypotheses.

While this apparent contradiction of the trade-off as-
sumption is intriguing, the limitations of our experiment
make it premature to reject the occurrence of physio-
logical trade-offs in these snails. We did not measure
responses in energy or other relevant units, nor did we
measure other physiological responses that may be in-
volved in trade-offs, e.g., growth of living biomass, egg
weight, or egg viability. Results do, however, suggest
that shell growth is "hardwired," i.e., it cannot be turned
off, even with senescence imminent in semelparous snails.

It is possible that a damaged snail might be more
vulnerable to subsequent attacks b\ predators. We did
not test this possibility , but suspect the eftect would be
minor. In lab experiments where crayfish damaged shells
(Olsen, 1989), crayfish appeared to curtail an attack be-
cause the remaining shell was simpK- too strong to break.
In addition, the earlier experiments probabK enhanced
the frequency of shell damage over natural frequencies
by enhancing encounter rates between predator and prey.
Thus, it seems unlikely that non-lethal shell damage by
cra\fish would have any impact on snail population
growth.

ACKNOWLEDGEMENTS

We thank Mark Olsen for helpful suggestions on the
design of this experiment, which was derived from a
similar preliminary experiment conducted b\ Olsen.
Thanks also go to Ronald Hellenthal, Martin Berg, Mi-
chael Dini, Kathleen McTigue and students of the UN-
DERC" program, who all helped in the research. Geerat
Vermeij. Robert Dillon, Roy Stein, and Ken Brown pro-
vided helpful reviews of the manuscript. Financial sup-
port for this project was provided by the Hank Family
Endowment for I'NDERC and grants to David M. Lodge
(NSFBSR-8500775 and NSFBSR-8907407). This is a con-

T. Stahl and D. Lodge, 1990

Page 95

tribution from the ITniversity of Notre Dame Environ-
mental Research Center.

LITERATURE CITED

Boerger, H. 1975. .\ comparison of the life c>cles. reproduc-
tive ecologies, and size-weight relationships of Helisoma
anceps, H. aimpai^ulata. and H trivolvis (Gastropoda,
Planorbidae). Canadian Journal of Zoolog\ 53;1812-1S24.

Brown, K. M. and B. A. Strouse. 1988. Relative vulnerability
of six freshwater gastropods to the leech Nephelopsis ob-
scura (Verrill). Freshwater Biology 19:157-166,

Crowl. T. A. 1989. Direct and indirect effects of crayfish
(Orconectes virilis) predation on snail {Physella virgata
virgata ) population d\ namics in spring-fed streams. Ph.D.
dissertation. The L niversits of Oklahoma, 139-1- pp.

Garrity, S. D, S. C. Levings, and HM Caffey. 1986. Spatial
and temporal variation in shell crushing by fishes on rocky
shores of Pacific Panama. Journal of Experimental Marine
Biology and Ecology 103:131-142,

Geller. J B 1990. Reproductive responses to shell damage
by the gastropod \ucclla emarginata (Deshayes). Journal
of Experimental Marine Biolog) and Ecology 136:77-87.

Kirkwood, T. B. L. 1981. Repair and its evolution: survival
versus reproduction. In: Townsend, C R. and P Calow
(eds. ). Ph\'siological ecology: an evolutionary approach to
resource use. Blackwell Scientific Publications, Boston, p.
165-189.

Lodge. D. M., K. M. Brown, S. P. Klosiewski, R. .A. Stein, A.
P. Covich, and C. Bronmark 1987. Distribution of fresh-
water snails: spatial scale and the relative importance of
physicochemical and biotic factors. .'American Malaco-
logical Bulletin 5:73-84.

Lodge, D M and J G Lorman 1987 Reductions in sub-
mersed macrophyte biomass and species richness by the
crayfish Orconectes rusticus. Canadian Journal of Fish-
eries and Aquatic Science 44:581-597.

Norton, S. F. 1988. Role of the gastropod shell and operculum
in inhibiting predation by fishes. Science 241:92-94

Olsen, T. M. 1989. Impact of the introduced crayfish, Or-
conectes rusticus, in Northern Wisconsin lakes: field and
laboratory studies. M.S. thesis, Universitv of .Notre Dame.

Osenberg, C W and G. G Mittelbach. 1989. Effects of body
size on the predator) -prey interaction between pumpkin-
seed sunfish and gastropods. Ecological Monographs .59:
405-432.

Raffaelli, D. G. 1978. The relationship between shell injuries,
shell thickness and habitat characteristics of the intertidal
snail Littorina rudis Maton. Journal of Molluscan Studies
44:166-170

Stein. R. A., C. G. Goodman, and E. A. Marschall. 1984. Using
time and energetic measures of cost in estimating prey
value of fish predators. Ecolog\ 65:702-715.

Tilman, D. 1989. Discussion: population dynamics and species
interactions. In: Roughgarden, J., R. H. May, and S A.
Levin (eds.). Perspectives in Ecological Theor\ Princeton
University Press. Princeton, p. 89-100.

Vale, F. K. and M. A. Rex. 1989 Repaired shell damage in
a complex of Rissoid gastropods from the Upper Conti-
nental Slope south of New England. The Nautilus 103:
105-108.

Vermeij, G. J. 1979. Shell architecture and causes of death
in micronesian reef snails. Evolution 33: 686-696.

Vermeij, G. J. 1982 Gastropod shell form, breakage, and
repair in relation to predation b\ the crab Calappa. Maia-
cologia 23:1-12.

Vermeij, G. J and \ P. Covich. 1978. Coevolution of fresh-
water gastropods and their predators. American Naturalist
112:833-843.

Vermeij, G. J., E. Zipser, and E. C Dudley 1980 Predation
in time and space: peeling and drilling in terebrid gastro-
pods. Paleobiolog)' 6:352-364.

Weber, L. M. and D. M. Lodge. 1990. Periph\tic food and
predatory crayfish: relative roles in determining snail dis-
tribution Oecologia 82:33-39.

Zipser, E and G. J. Vermeij. 1980. Survival after nonlethal
shell damage in the gastropod Conus sponsalis. Micro-
nesica 16:229-234.

THE NAUTILUS 104(3):96-104, 1990

Page 96

New Gastropods from the Bermont Formation
(Middle Pleistocene) of the Everglades Basin

Edward J. Peluch

Dtpartnicnt of Geology-
Florida Atlantic University
Boca Ralon, FL 33431, USA

ABSTRACT

Eight new gastropods are described from tfie poorly-known
basal beds ("Holey Land Unit") of the middle Pleistocene Ber-
mont Formation of the Everglades Basin. The new species
include Cypraea (Macrocypraea) spengleri n.sp. and Cypraea
(Pseudozonaria) portelli n.sp. (Cypraeidae), Melongena (Mic-
cosukca) cynthiae n.sp, and Melongena {Miccosukea) holey-
landica n.sp, (Melongeiiidae), Scaphella seminole n.sp. (Volu-
tidae), and Conus capelettii n.sp., Contis griffini n.sp., and
Conufi lemoni nsp, (Conidae). Also described is a new subgenus
of Melongena Schumacher, 1817, Miecosukea n.subgen., which
represents an endemic Pleistocene species radiation from within
the Everglades region.

Key words: Gastropods; Pleistocene; Everglades; Florida.

INTRODUCTION

Of the major surficial stratigraphic units of the Ever-
glades Basin of southern Florida, the middle Pleistocene
Bermont Formation is the least known and the most
poorly studied. Indeed, the formation did not even re-
ceive an official designation until 1974, when DuBar
informally named and described this important set of
units. Previously (i.e., McGinty, 1970; Hoerle, 1970), the
formation was simply referred to as "Unit A" or the
"Glades Unit," or, prior to that time, as the "un-named
post-Caloosahatchee formation" (i.e., E. Voices, 1968).
Although the formation name still has not been accepted
by regional offices of the United States Geological Survey
(fide Wesley L. Miller, Water Resources Division, USGS,
Miami), several workers in the Pleistocene paleontology
of southern Florida have adopted its usage and recognize
its importance as the "missing link" in the stratigraphic
record of the Everglades region (i.e., E. Yokes, 1976,
1984; Petuch, 1988). Since the depositional center of the
formation is within the Everglades Basin where there
are few sampling sites, only sporadic collections of Ber-
mont material have been made and the molluscan fauna,
particularly the gastropod component, is known from
only a handful of publications.

In response to increased building and construction in
southern Florida, several large new land fill (juarries have

been excavated within the Everglades region over the
last few years. Two of these in particular, the Capeletti
Brothers pit #11 in northern Dade County and the Grif-
fin Brothers pit on the Brow ard-Palm Beach County line,
have cut into extremely fossiliferous beds of the Bermont
Formation and have uncovered many new and interest-
ing gastropods. Besides new species, both quarries have
yielded large numbers of classic Bermont index fossils
(as listed by McGinty, 1970; DuBar, 1974; and Petuch,
1988, 1989) such as Melongena (Rexmela) hispinosa
(Philippi, 1844), Fasciolaria okecchobeensis Tucker and
Wilson, 1932, Latirus maxwelli Pilsbry, 1942, Vasum
floridanum McGinty, 1940, Fusinus watermani (M.
Smith, 1940), and Stromhua mayacensis Tucker and Wil-
son, 1933, demonstrating the contemporaneous nature
of their beds. Several other newly-described index fossils,
including Lindoliva griffini Petuch, 1988, Lindoliva
spengleri Petuch, 1988, and Maica petiti Petuch, 1989
were also collected in both quarries, indicating that the
dredged fossiliferous sediments came from the same
stratigraphic horizon.

At both quarries, the Bermont Formation is approxi-
mately 10 meters thick and is stratigraphically more
complex than had previously been reported (DuBar,
1974). Of particular interest are the basal beds of the
formation, w hich contain a large number of undescribed
gastropod species. Although containing the same species
at both localities, the basal beds in the Capeletti Brothers
pit are marly and unconsolidated whereas the strati-
graphic equivalents in the Griffin Brothers pit are in-
durated into a thick la\ er of dense limestone. This richly
fossiliferous indurated bed (figure 22), which averages 2
meters in thickness and is found at a depth of approxi-
mately 15 meters below surface, has also been uncovered
at construction sites in the Loxahatchee area of West
Palm Beach and south of South Ba\, along the North
New River Canal in central Palm Beach County. The
most numerous and largest blocks of this Bermont lime-
stone, however, have been dredged from the Griffin
Brothers pit. Since the Griffin pit and its exposures of
Bermont material are adjacent to the Holey Land Wild-
life Refuge (named for the numerous shallow craters
formed by World War II bombing practice, ^c/f" Howard

E. J. Petuch, 1990

Page 97

A. Griffin, Jr.), the basal indurated bed has been infor-
malK referred to by local paleontologists as the "Holey
Land Unit, " A cursory survey of the gastropods of the
Holey Land LInit has shown that a large percentage of
the species appear to be undescribed and that several
belong to previousK unknown subgenera and species
complexes.

In this paper, eight new gastropod species and a new
gastropod subgenus are described from the basal beds
("Holey Land Unit") of the Bermont Formation. In-
cluded are Cypraea (Macrocypraea) spengleri n.sp. and
Cypraea (Pseudozonaria) portclli n.sp. (Cypraeidae),
Melongena (Miccosiihca) cynthiae n.sp. and Melongena
{Miccosiikea) holeylandica n.sp. (Melongenidae), Sca-
phella Seminole n.sp. (N'olutidae), and Coniia capelettii
n.sp.. Conns griffini n.sp., and Conns lemoni n.sp. (Co-
nidae), and the new subgenus of Melongena, Miccosukea
n.subgen. Institutional abbreviations, for the deposition
of t\'pe material, include: USNM (Department of Paleo-
biology, National Museum of Natural History, Smith-
sonian Institution), UF (Florida Museum of Natural His-
tory, Universit) of Florida, Gainesville, Florida), CM
(Department of Paleontology, Carnegie Museum of Nat-
ural History, Pittsburgh, Pennsylvania), and FALI (De-
partment of Geology, Florida Atlantic University, Boca
Raton, Florida).

SYSTEMATICS

Gastropoda

Prosobranchia

Cypraeacea

Cypraeidae

Cypraea Linnaeus, 1758

Macrocypraea Schilder, 1930

Cypraea (Macrocypraea) spengleri new species
(figures 5, 6)

Material examined: HOLOTYPE — Length 107 mm,
dredged from 20 m depth in Capeletti Brothers pit #11,
7 km west of Florida Turnpike, due west of Hialeah.
northeastern Dade County, Florida, CM 35728; PARA-
TYPES — Length (fragmentary) 105 mm, dredged from
15 ni depth in Griffin Brothers pit, 10 km west of US
Highway 27, along Palm Beach-Broward County line,
Florida, FAU 320; length 120 mm, internal mold, same
locality as previous paratype, FAU 321; length 158 mm,
same locality as previous two paratypes, Spengler col-
lection. Lantana, Florida; length 83 mm, same locality
as holotype, Petuch collection.

Description: Shell typical of subgenus, large, inflated,
subcylindrical; aperture narrow, widening toward an-
terior end, arcuate; columella (holotype) with 33 narrow
teeth that extend into aperture; lip with 44 narrow teeth;
fossula poorK developed, with 9 narrow teeth; base of
shell rounded; auricles (extrapolated from damaged type
material) well developed, projecting; color pattern (faint-
ly preserved on holotype) composed of numerous small,
widely-scattered round spots.

Etymology: Named for Mr. John Spengler of Lantana,
F"lorida, who has helped me collect at several important
fossil sites in the Everglades.

Discussion: Cypraea spengleri represents the first new-
species of the subgenus Macrocypraea to be described
from the fossil record of the continental United States,
and is the largest cowrie known from the Neogene of
Florida. The cypraeid fragments from the "Glades Unit"
of the Belle Glade pit, listed by Hoerle (1970:63) as
"Cypraea ?cenms Linne," are probably referable to C.
spengleri. The "Cypraea cervus" from Belle Glade and
Ortona Lock, listed by McGinty (1970:55), is also prob-
ably C. spengleri. Based on the specimen in the Spengler
collection (158 mm paratype), I also previously referred
the new species to C. cervus (Petuch, 1988: plate 24, fig.
10). As molds, C. spengleri is relatively common in the
Holey Land limestone at the Griffin Brothers pit. but the
preservation is poor and most specimens are fragmen-
tary. Complete specimens such as the holotype, however,
have only been collected in the unconsolidated marly
facies of the Holey Land Unit in northern Dade County.
Cypraea spengleri is most similar to C. (Macrocy-
praea] cervus Linnaeus, 1771 from the Carolinian Prov-
ince and, based on its similar shape and size, is probably
the direct ancestor of that well known Recent species.
The main difference between the two cowries, however,
is seen in the form of the apertural teeth, particularly
those of the columella; in C. cervus, the columellar teeth
are slender and elongated, extending well onto the base
of the shell (figure 7), while in C. spengleri. the colu-
mellar teeth are short and coarse and do not extend onto
the base but. instead, terminate along the edge of the
columella (figure 6). Likewise, the labial teeth of C cer-
vus are finer and more elongated than those of C. spen-
gleri. and also extend farther onto the shell base. The
number of apertural teeth also differs between the two
species, with C. cervus having more teeth (average 37
columellar. 43 labial) than C. spengleri (average 33 col-
umellar, 40 labial).

Pseudozonaria Schilder. 1927

Cypraea (Pseudozonaria) portelli n.sp.
(figures 8. 9. 10)

Material examined: HOLOTYPE — Length 25 mm,
dredged irom 15 m depth in Griffin Brothers pit, 10 km
west of US Highwav 27, at Broward-Palm Beach Countv
line, Florida, UF 28985; PARATYPE— Length 25 mm,
from 20 m depth in Capeletti Brothers pit #11, 7 km
west of Florida Turnpike, northeastern Dade County-,
Florida, Petuch collection.

Description: Shell average size for subgenus, oval in
outline, dorsoventralK flattened; beaks yvell developed,
projecting; margins thickened, sharply angulate; base
slightly rounded; spire region shalloyvly indented; ap-
erture narroyv, slightly arcuate; teeth blunt and coarse,
numbering 15 along columella and 19 along lip (of ho-

THE NAUTILUS, Vol. 104, No. 3

Figures 1-10. New Melongenids and Cypraeids from the "Holey Land Unit" of the Bermont Formation 1. Melongena (Mic-
cosukea) cijnthiae n.sp . dorsal view of paratype, length .5.5 mm; 2. Melongena (Miccosuke(2)cynthiae n sp., ventral view of holotype,
length 38 mm; 3, 4. Melongena (Miccosukea) holeylaiulica n.sp., dorsal and ventral views of holot\ pe, length .35 mm; 5. 6. Cypraea
{Macrocypraea) spengleri n.sp., dorsal and ventral views of holotype, length 107 mm; 7. Cypraea (Macrocypraea) cervus Linnaeus,
1771, ventral view of 85 mm specimen, for comparison with C. (Macrocypraea) spengleri. 8, •). Cypraea (Pseiidozonaria) portelli
n.sp., dorsal and ventral views of holotype, length 25 mm; 10. Cypraea {Pseiidozonaria) porlelli n sp., lateral view (left) of holotype.

E. J. Petuch, 1990

Page 99

lotype); color pattern (faintly preserved on holotype)
composed of numerous, denseK -packed specklings, often
fusing together to form longitudinal stripes, on the dor-
sum and numerous evenly-spaced small spots on margins;
anterior and posterior tips each with 2 large patches.

Etymology: Named for Mr. Roger Portell, Florida Mu-
seum of Natural History, who collected the holotype.

Discussion: Cypraea portelli represents the first species
of its subgenus to be found in the fossil record of the
United States. Until now, Pseudozonaria was unknown
in the Caloosahatchian Province (Miocene to Pleistocene
S.E. United States and the Floridian Peninsula), and was
thought to have been confined to the Gatunian Province
(Miocene to Pleistocene Caribbean, northern South
America, and western Central America) (Petuch, 1982;
Vermeij & Petuch, 1986). In the Recent, the subgenus is
represented by three species from the Panamic Province
of the tropical western Americas; C. [Pseudozonaria)
arobicula (Lamarck, 1811), C. (Pseudozonaria) nigro-
punctata Gray, 1828, and C. (Pseudozonaria) robertsi
(Hidalgo, 1906). Of the three living species, C. (Pseu-
dozonaria) portelli is most similar to C. robertsi, being
the same size and having the same type of apertural
teeth, shape and form of the aperture, and color pattern.
The new species differs from C. robertsi, however, in
having a broader, more rounded outline and in having
angled, thickened margins.

In the fossil record of the Gatunian Province of the
Caribbean basin, C. portelli is most similar to C. ray-
mondrobertsi bowdenensis (Pilsbry, 1922) from the Plio-
cene of Jamaica and the Dominican Republic. Both spe-
cies share the same broad, oval shell outline and the same
flattened appearance. The apertural teeth of C. raij-
mondrobertsi bowdenensis, however, are proportionally
much larger and better developed than those of C. por-
telli, and extend much farther across the base of the
shell. Cypraea portelli was probably the last Pseudozo-
naria to live in the Atlantic.

Buccinacea

Melongenidae

Melongeninae

Melongena Schumacher, 1817

Miccosukea new subgenus

Diagnosis: Shells average-sized for genus, but more
elongated and fusiform, generally resembling Fasciola-
ria species in outline; shoulders, especialK' those of body
whorls, rounded, without prominent spines or Dutings;
shoulders of whorls ornamented with low, rounded knobs
or evenly-spaced low, rounded axial ribs; spires and body
whorls both heavily sculptured with numerous strong
spiral cords; spiral cords finer and more numerous on
siphonal canals; siphonal canals very well-developed,
elongated; siphonal canals of some species well-differ-
entiated from body whorl, narrow, giving shells appear-
ance of small Pugilina or Busycon species; aperture wide,
flaring, oval in shape; spire height and development vari-

able within subgenus, with some species having elevated,
scalariform spires and others having low, slightly-stepped
spires; sutures slightly impressed, smooth, without fine
fimbriations or crenulations.

Type species: Melongena (Miccosukea) cynthiae new
species, described here. Lower beds ("Holey Land Unit")
of Bermont Formation, Aftonian Stage, Pleistocene, Palm
Beach County, Florida (figures 1, 2).

Other species in Miccosukea: Melongena (Miccosukea )
holeylandica new species, described here. Lower beds
("Holey Land Unit") of Bermont Formation, Aftonian
Stage, Pleistocene, Palm Beach County (figures 3, 4);
Melongena (Miccosukea) sp., fragmentary, Bermont
Formation, Aftonian (Yarmouth?) Stage, Pleistocene,
Dade County, Florida.

Etymology: The new subgenus honors the Miccosukea
Seminole Tribe of the Everglades.

Discussion: The new subgenus represents a separate
evolutionary line off the Melongena Schumacher, 1817
(sensu stricto) stock, and appears to have been endemic
to southern Florida. This local radiation differs from
classic Melongena species in containing smaller, more
fusiform shells with better-developed and more elon-
gated siphonal canals, and in lacking sutural fimbriations
and large shoulder spines. Miccosukea also differs from
the subgenus Rexmela Olsson and Harbison, 1953 in
being more fusiform in shape, in having much better
developed siphonal canals, in lacking large shoulder
spines, and in lacking the "collar" of fimbriations bor-
dering the suture.

At several Bermont localities, Melongena (Miccosu-
kea) species and Melongena (Rexnuda) species, such as
M. (Rexmela) bispinosa (Philippi, 1844), occur together
and show that the two subgenera were sympatric.

Melongena (Miccosukea) cynthiae new species

(figures 1, 2)

Material examined: HOLOTYPE — Length 38 mm,
dredged from 15 m depth in Griffin Brothers pit, 10 km
west of US Highway 27, at Broward-Palm Beach Countv
line, Florida, USNM 448813; PARATYPES— Length 55
mm (incomplete), same locality as holotype, FAU 322
(figure 1); lengths 41 and 52 mm, same locality as ho-
lotype, FAU 323; length 64 mm, same locality as holo-
type, Petuch collection.

Description: General shell shape and form as for sub-
genus; spire protracted, scalariform; spire v\ horls convex;
suture impressed; spire, body whorl, and siphonal canal
heavily sculptured with numerous large, evenly-spaced
spiral cords; smaller secondary cords present between
large primary cords.

Etymology: Named for Mrs. C\iithia Mischler, De-
partment of Geology, Florida Atlantic L'niversitv .

Discussion: Melongena cynthiae, type of the new sub-
genus, more closely resembles a small Pugilina Schu-

Page 100

THE NAUTILUS, Vol. 104, No. 3

machcr, 1817 species than it does other western Atlantic
melongenids. UnUke Pugilina species, M. cynthiae has
a distinctly rounded shoulder on the body whorl, rounded
and convex spire whorls, and an impressed suture. In
having a protracted, scalariform spire, the new species
somewhat resembles high-spired forms of Melongena
(Rexmela) corona (Gmelin, 1791), such asaltispira Pils-
bry and Vanatta, 1934. Melongena cynthiae differs from
these high-spired forms, however, in having a much more
elongated body whorl and in having a much better de-
veloped, and longer, siphonal canal. Being in Miccusii-
kea, M. cynthiae also lacks the open shoulder spines and
fimbriated sutures of Rcxnicla species.

The new species is also similar to the stratigraphically
higher Melongena (Miccosukea) holeylandica n.sp. (fig-
ures 3, 4), but differs in having a much higher, scalari-
form spire, in having a longer siphonal canal, and in
being more heavily sculptured with strong spiral cords.
A large, undescribed Miccosukea species has also been
collected, although only as fragments, in the uppermost
beds of the Bermont Formation in the Capeletti Brothers
pit. This un-named species also has a high, scalariform
spire, but has a smoother, less sculptured shell. The "Mel-
ongenid-new genus, new species" that I previously il-
lustrated (Petuch, 1988: plate 24, figs. 1, 2) is M. cynthiae.

Melongena (Miccosukea) holeylandica new species
(figures 3, 4)

Material examined: HOLOTYPE — Length 35 mm,
dredged from 12 m depth in Griffin Brothers pit, 10 km
west of US Highway 27, at Broward-Palm Beach County
line, Florida, USNM 448814; PARATYPES— Lengths 48,
51, and 55 mm, same locality as holotype, FAU 324;
length 52 mm, same locality as holotype, Petuch collec-
tion.

Description: General shell shape and form as for sub-
genus; spire low, rounded, slightly dome-shaped; sub-
sutural area raised to form large, rounded spiral cord;
subsutural cord producing minutely canaliculate suture;
spire, body whorl, and siphonal canal sculptured with
low, faint spiral cords; shoulder of body whorl orna-
mented with scattered small, low knobs; siphonal canal
broad.

Etymology: Named for the area adjacent to the type
locality, the Holey Land Wildlife Refuge.

Discussion: The similarities and differences between
Melongena holeylandica and the only other named Mic-
cosukea species, M cynthiae, are discn.s.sed under the
preceding description. The "Melongenid-nev\ genus, new
species" that I previously illustrated (Petuch, 1988: plate
24, figs. 5, 6) is M holeylandica.

Volutacea

Volutidac

Scaphellin; •

Scaphella .'■ u ;rvn, 1832

Scaphella seminole new species
(figures 18, 19, 20, 21)

Material examined: HOLOTYPE — Length 52 mm,
dredged from 20 m depth in Capeletti Brothers pit #11,
7 km west of Florida Turnpike, due west of Hialeah,
northeastern Dade County, Florida, CM 35729; P.\R,\-
TYPES — Length 53 mm, same locality as holotype, CM
35730 (figures 20, 21); lengths 54, 55, and 56 mm, same
locality as holotype, FAU 325; lengths 55, 56 mm, same
locality as holotype, Petuch collection.

Description: Shell small for genus, fusiform, with
rounded, sloping shoulder; spire proportionally low, with
sloping whorls; top of shoulder marked with faintly in-
cised, shallow furrow; area between suture and shoulder
furrow producing wide, faintK raised subsutural band;
protoconch proportionalK large, rounded, domelike, with
rounded calcarella; first 2 postnuclear whorls heavily
sculptured w ith numerous, evenly-spaced, large axial ribs;
axial ribs overlaid with numerous fine spiral threads,
producing slightly cancellate appearance; columella with
4 large plications; color pattern, when preserved, com-
posed of 7-9 rows of large, evenly-spaced rectangular
checkers.

Etymology: Named for the Seminole Indian Tribe of
the Everglades region.

Discussion: Scaphella seminole is the smallest of the
known fossil Scaphella species, with the average length
of the type lot (all adult specimens with thickened, pos-
teriorly-Daring lips) being only around 54 mm. The new-
species is similar to the late Pliocene-earK Pleistocene
Caloosahatchee Formation S. floridana (.Heilprin, 1886),
but differs in having a much smaller, stumpier shell with
a much lower, unprotracted spire. The axial ribbing on
the postnuclear whorls of S. floridana is also coarser and
better developed than that of S. seminole and extends
onto the third whorl.

Conacea
Conidae
Conus Linnaeus, 1758

Conus capelettii new species
(figures 11, 12, 13)

Material examined: HOLOTYPE — Length 38 mm,
dredged from 20 m depth in Capeletti Brothers pit #11,
7 km west of F'lorida Turnpike, due west of Hialeah,
northeastern Dade C:ount\, Florida, CM 35731; PARA-
TYPES— Length 33 mm, same localit\ as holot\ pe, CM
35732 (figure 13); lengths 36, 39, 41, and 42 mm, same
localits as holotype, Petuch collection.

Description: Shell slender, elongateK subpyriform, bi-
coiiic; shoulder sharply angled, carinated; spire very pro-
tracted, scalariform; body whorl and spire smooth, with
silky texture; anterior end encircled with 8-10 deep,
evenly-spaced grooves; aperture narrow, widening slightly

E. J^ Petuch, 1990

Page 101

Figures 11-21. New Conids and Volutids from the "Holey Land Unit" of the Bermont Formation. 11, 12. Conus capelettii
n.sp., dorsal and ventral views of holotype, length 38 mm; 13. Conus capelettii n.sp, dorsal view of paratspe, length 33 mm: 14,
15. Conus griffini n.sp., dorsal and ventral views of holotype, length 15 mm; 16. 17. Conus lemoni n.sp., dorsal and ventral views
of holotype, length 56 mm; 18, 19. Scaphella seminole n.sp., dorsal and ventral views of holotype, length 52 mm; 20, 21. Scaphella
Seminole n.sp., dorsal and ventral views of parat\pe, length 53 mm.

Page 102

THE NAUTILUS, Vol. 104, No. 3

Figure 22. Detail of a fossiliferoiis liincstone block from the lia.sal beds ("Holey Land Unit") of the Bermont Formation. This
block was dredged from 15 rn depth in the (iriffin Brothers pit on the Palm Beach-Broward County line in the central Everglades
Basin. The lucinids on the left and lower left are approximately 60 mm in diameter

toward anterior end; color pattern, ulieii preserved, com-
posed of wide longitudinal flaiiumiles and zig-zags.

Etymology: Named for Mr. Ronald Capeletti, of Ca-
peletti Brothers, Inc., Hialeah, Florida, in thanks for al-
lowing me to collect large suites of Bermont material on
his property.

Discussion: Conns capelettii has the highest, most sca-
lariform spire of any cone shell known from the Plio-
Pleistocene fo.ssil record of Florida. Based on shell shape,
size, and spire form, the new species appears to be more
closely relatetl to Conns scalaris Valenciennes, 1832 from
the Recent western coast of Mexico than to other western
Atlantic cone shells. C.'of!(/.s capelettii differs from C.

E. J. Petuch, 1990

Page 103

scalaris, however, in having a proportionally shorter body
whorl with a distinctly more pyriform shape. The new
Berniont species is also similar in shape to some slender
morphs of the Recent Carolinian Province C. floridanus
Gabb, 1868, but differs primarily in having a sharper,
more carinated shoulder and in having a much higher,
scalariform spire.

Conus griffini new species
(figures 14, 15)

Material examined: HOLOTYPE — Length 15 mm,
dredged from 15 m depth in North New River Canal,
along US Highway 27, 30 km south of South Bav. Palm
Beach C:ount> , Florida, CM 35733; PARATYPE— Length
18 mm, dredged from 15 m depth in Griffin Brothers
pit, 10 km west of US Highway 27, at Broward-Palm
Beach County line, Florida, Petuch collection.

Description: Shell small for genus, slender, straight-
sided; shoulder sharply angled, carinated; spire low and
flattened; body whorl smooth and shiny; anterior tip en-
circled with 8-10 low, rounded cords; aperture narrow;
protoconch mammillate, projecting above spire line; col-
or pattern, when preser\ed, composed of single row of
small spots around midbod\

Etymology: Named for Mr. Howard A. ("Andy") Grif-
fin, Jr., Davy, Florida, in thanks for allowing me to collect
on his propert) over the last eight years.

Discussion: Conus griffini is the first member of the C.
magellanicus Hwass, 1792 species complex to be found
in the fossil record of continental North America. In the
Recent, this complex of small cones is confined to shallow
water, coral reef areas of the West Indies, Bahamas, and
Caribbean Basin. The new Bermont species is most sim-
ilar to the Recent C. kalafuti DaMotta, 1987 from Roatan
Is., Honduras, and both cones have the same small size,
flat spire, projecting nipple-like protoconch, and color
pattern composed of a checkered midbody band. Conus
griffini differs from C. kalafuti, however, in having a
more slender, straight-sided shell and in having stronger
spiral cords around the anterior tip. Otherwise, the two
species are very similar, and C. griffini is most probably
the ancestor of the Honduran C. kalafuti.

Previously (Petuch, 1988: plate 23, fig. 2), 1 had illus-
trated and referred to this new Bermont cone as "Conus
cf. eversoni Petuch, 1987." That species, which is also
related to C. kalafuti and is also from Roatan Is., Hon-
duras, has a larger and more elongated shell than C.
griffini. The protoconch of C. griffini is also proportion-
ally larger than that of C. eversoni and is more promi-
nentlv mammillate.

Conus lemoni new species
(figures 16, 17)

Material examined: HOLOTYPE— Length 56 mm,
dredged from 15 m depth in Griffin Brothers pit, 10 km

west of US Highway 27, at Broward-Palm Beach County
line, Florida, CM 35734; PARATYPES— Length 49 mm,
same localit>- as holotype, CM 357.35; lengths 37, 45, 48^
and 68 mm, same locality as holotype, FAU 326; length
65 mm, dredged from 20 m depth in Capeletti Brothers
pit #11, 7 km west of Florida Turnpike, due west of
Hialeah, northeastern Dade County, Florida, Petuch col-
lection.

Description: Shell broad, heavy, with wide shoulder;
shoulder angled, with rounded edge; spire low, flattened,
with early whorls projecting above later whorls; suture
indented; spire w liorls distinct!) canaliculate; bodv whorl
heavily sculptured v\ ith numerous, closely-packed, large
spiral cords; aperture narrow; color pattern, when pre-
served, composed of numerous rows of small spots, often
arranged in bands, and scattered large axial flammules
that often coalesce to form longitudinal stripes; spire
marked with evenly-spaced crescent-shaped flammules.

Etymology: Named for Dr. Roy Lemon, Department
of Geology, Florida Atlantic University.

Discussion: Conus lemoni is a new member of the Co-
nus spurius, 1791 species complex of the Pliocene-to-
Recent Caribbean and Floridian regions. Morphologi-
cally, the new Bermont species combines the shell char-
acters of tw o Recent species, C. spurius atlanticus C:lench,
1942 and C. lorenzianus Dillwyn, 1817. In having a
broad shell shape, rounded shoulder edge, and low spire,
C. lemoni resembles the Carolinian C. spurius atlanti-
cus. On the other hand, in being hea\ il\ sculptured \\ ith
closeK-packed spiral cords and in having a flammulated
color pattern, the new Bermont cone resembles the south-
western Caribbean C. lorenzianus. It is possible that C.
lemoni is ancestral to both closely-related species.

In the Florida fossil record, C. lemoni is similar to
several undescribed subspecies of C. spurius from the
upper beds of the Bermont Formation and the overlying
Fort Thompson Formation (late Pleistocene). The new
Holey Land species differs from the younger C. spurius
subspecies, however, in having distinctly canaliculate spire
whorls and in being heavik' sculptured with spiral cords.

ACKNOWLEDGEMENTS

I thank Mr. John Spengler, Lantana, Florida, for assisting
me in the collection of Bermont fossils, and Mr. Howard
("And\") Griffin, Jr., and Mr. Ronald Capeletti for al-
lowing me to collect on their propert) . Special thanks to
Mrs. Cynthia Mischler for patientK t\ping the manu-
script.

LITERATURE CITED

DuBar, J R 1974 Suinmar\ ot tlie N'eogene stratigraphy of
southern Florida In: Oaks, R. Q. and J R DuBar (eds.)
Post-Miocene stratigraph) , Central and Southern .Atlantic
Coastal Plain. Utah State University Press, p. 206-231.

Hoerle, S, E 1970 Mollusca of the "Cllades" unit of .southern

Page 104

THE NAUTILUS, Vol. 104, No. 3

Florida: Part II. List of Molluscan species from the Belle
Glade Rock Pit, Palm Beach C:oiint\ , Florida. Tiilane Stud-
ies in Geology and Paleontology 8(2):56-68.

McGinty, T. L. 1970. Mollusca of the "Glades" unit of south-
ern Florida: Part I. Introduction and observations. Tulane
Studies in Geology and Paleontology 8(2):53-56.

Petuch, E. J. 1982. Geographical heterochrony: contempo-
raneous coexistence of Neogene and Recent molluscan
faunas in the .Americas. Palaeogeography , Palaeoclima-
tology, and Palaeoecology 37:277-312.

Petuch, E. J. 1988. Neogene history of tropical .American
mollusks. The Coastal Education and Research Founda-
tion, Charlottesville, Virginia. 217 p.

Petuch, E. J. 1989. New species of Malea (Gastropoda Ton-
nidae) from the Pleistocene of southern Florida. The Nau-
tilus 103(3):92-95.

\ ernieij, G J. and E. J Petuch 1986. Differential extinction
in tropical .American molluscs: endemism, architecture,
and the Panama Land Bridge. Malacologia 27(1):29-41.

\okes, E. H. 1968. Cenozoic Muricidae of the Western .At-
lantic Region. Fart IV — Hexaplex and Murexiella. Tulane
Studies in Geology 6(3):85-126.

N'okes, E. H. 1976. Cenozoic Muricidae of the Western .At-
lantic Region. Part VII — Calotropbon and Attiliosa. Tu-
lane Studies in Geology and Paleontology 12(3):101-132.

Vokes, E. H. 1984. A new species of Turbinella (Mollusca:
Gastropoda) from the Pliocene of Mexico, with a revision
of the geologic history of the line. Tulane Studies in Ge-
ology and Paleontology 18(2):47-52.

THE NAUTILUS 104(3): 105-107, 1990

Page 105

Micropilina tangaroa, a New Monoplacophoran
(Mollusca) from Northern New Zealand

B. A. Marshall

National Museum of New Zealand

Box 467

Wellington, New Zealand

ABSTRACT

Micropilina tangaroa n.sp., based on a single shell from the
Three Kings Rise, northern New Zealand, is the first record of
the class Monoplacophora from the western Pacific.

Key words: Monoplacophora; New Zealand; Micropilina.

the multiple muscle attachment scars characteristic of
many species of the class (figure 3) (Lemche & Wing-
strand, 1959; Wingstrand, 1985), The class name is gen-
erally credited to Wenz (in Knight, 1952), but, as indi-
cated by Waren (1988), it was first introduced bv Odhner
{in Wenz, 1940).

INTRODUCTION

Since the discovery of Neopilina galathea in 1952
(Lemche, 1957), 14 Recent species have been added to
the class Monoplacophora (Lemche, 1957; Clarke & Men-
zies, 1959; Menzies & Layton, 1963; Tebble, 1967; Men-
zies, 1968; Rokop, 1972; McLean, 1979; Moskalev et al,
1983; Bouchet et al, 1983; Waren, 1988, 1989; Waren
& Bouchet, 1990). These species are based on material
from off Hawaii, the eastern Pacific margin, the western
and northern Atlantic, and the Gulf of Aden. The present
record extends the range to the southwestern Pacific (fig-
ure 1). Recent monoplacophorans are mainly confined
to bathyal and abyssal depths, though one species lives
at 174-388 m depth off southern California (McLean,
1979). Monoplacophoran morphology and anatomy have
been discussed in detail by Lemche and Wingstrand
(1959) and Wingstrand (1985), while Menzies e< al. (1959)
and Tendal (1985) have discussed their ecology and diet.

Class Monoplacophora Odhner in Wenz, 1940

Genus Micropilina Waren, 1989:2

Type species: Micropilina minuta Waren, 1989, by
original designation; Recent, northern Atlantic.

Remarks: Suprageneric classification of the Monopla-
cophora has been drastically modified by Moskalev et
al. (1983) and Starobogatov and Moskalev (1987). These
authors placed the 11 Recent species then known into
six families and three superfamilies. Unfortunately the
anatomy of Micropilina is unknown, so it cannot be
placed in this hierarchial framework. Despite the lack
of supportive anatomical data, Micropilina species are
undoubtedly monoplacophorans, since their shells exliibit

Figure 1. Map of New Zealand showing t\pe localit\' (star)
for Micropilina tangaroa new species. 200 and 1000 meter
contours indicated

Lll

/w-

(f--

V ■

f .

•

'-P

Figures 2-5. Micwpilina tangawa new species. 2. Lett lateral, '.\. ventral, and l. dorsal views of holotype (length = L50 mm)
5. Detail of teleoconcfi sculpture (800 x ).

B. A. Marshall, 1990

Page 107

Micropilina tangaroa new species
(figures 2-5)

Description: Shell {holot\pe) 1.50 mm long, thin,
strongK arched capuliform; apertural margin regularly
(uate, concave from side to side; rounded apex projecting
slightly beyond anterior apertural margin, opaque white.
Shell wall apparently lamellar throughout, presumably
arganonite. Apical area convex, 0.17 mm long, defined
bv fine concentric ridge, surface slightly etched. Exterior
surface at 0.17-0.30 mm shell length essentially smooth
apart from few, fine raised concentric growth lines.
Thereafter sculptured with strong concentric ridges and
finer radial riblets. Concentric ridges close, sharply de-
fined, broader than high, summits weakK' convex, inter-
spaces about half width of each ridge, weaker and less
sharply defined beside apertural margin. Radial riblets
confined to interspaces of concentric ridges, rounded,
interspaces slightly narrower than each riblet, each riblet
about as wide as interspace of each concentric ridge.
Interior surface encircled by complex series of muscle
attachment scars, of which at least 15 pairs are discern-
able, through precise number of muscle attachment points
uncertain, especially over anterior half. Animal un-
known.

Type material: Holotype New Zealand Oceanographic
Institute, Wellington H.555 (length 1.50 mm, w idth 0.88
mm, height 0.50 mm).

Type locality: (Figure 1) Station U.602, 31°30.7'S,
172°49.8'E, northern Three Kings Rise, northern New-
Zealand, dead 1,216-1,385 m, rocky substratum with
pumice, carbonate sand and shell, February 9, 1988, R. V.
Rapuhia.

Etymology: The species is named for the Maori sea god
Tangaroa.

Discussion: Compared with the north Atlantic species
Micropilina miniita Waren, 1989, which it most resem-
bles, M. tangaroa differs in being larger (length 1.50 mm
compared with 1.06 mm), and in having concentric ridg-
es that are much larger both in actual size and in size
relative to the size of the radial riblets. Judging from the
increasing curvature of the posterior and lateral slopes
and the change (presumably senescent) in sculpture be-
side the apertural margin, the holotype of M. tangaroa
is evidently an adult. Apical pits recorded by Waren
(1988, 1989) were not observed in the present specimen,
which is long dead, locally stained by manganese de-
position, and slightly etched.

ACKNOWLEDGEMENTS

1 thank curatorial staff at New Zealand Oceanographic
Institute, Wellington, for access to sediment samples that
yielded the monoplacophoran, New Zealand Geological
Survey, Lower Hutt, for scanning electron microscopy,
Mark Strange for photographic printing and Kathleen
Ryan for word processing.

LITERATURE CITED

Bouchet, P., J H McLean, and A. Waren. 1983. .\lonopla-
copliorans in the North .■\tlantic. Oeeanologica Acta 6'.117-
118.

Clarke, A. H, and R. J. Menzies. 19.59, Seopilina (Vema)
ewingi, a second new living species of tlie Paleozoic class
Monoplacophora. Science 129:1026-1027.

Knight, J, B. 1952. Primitive fossil gastropods and their bear-
ing on gastropod classification. Smithsonian Miscellaneous
Collections 117(13):l-56.

Lemche, H, 1957 .\ new living deep .sea mollusc of the
Cambro-Devonian class Monoplacophora. Nature, London
179:41.3-416.

Lemche, H. and K G, Wingstrand. 19.59. The anatomy of
Neopilina galatheae Lemche, 1957. Galathea Report 3:9-
71.

McLean, J. H. 1979. A new monoplacophoran limpet from
the continental shelf off southern California. Contributions
in Science. Natural Historv Museum of Los Angeles Coun-
ty 307:1-19.

Menzies, R. J. 1968. New species of Ncopi/ina of the Cambro-
Devonian class Monoplacophora from the Mihie-Edwards
Deep of the Peru-Chile Trench, R/\' ,\nton Bruun Pro-
ceedings of the Symposium on Mollusca of the Marine
Biological .'Association of India 3:1-19.

Menzies, R. J. and W. Layton. 1963. A new species of mono-
placophoran mollusc, Neopilina (Neopilina) veleronis from
the slope of the Cedros Trench, Mexico. Annals and Mag-
azine of Natural History ser. 13, 5:401-406.

Menzies, R. J., M. Ewing, J, L. Worzel, and A. H. C;larke. 1959.
Ecologv of the Recent Monoplacophora. Oikos 10:168-
182.

Moskalev, L. 1., Y. I Starobogatov, and Z. A. Filatova. 1983.
New data on the abyssal Monoplacophora from the Pacific
and South Atlantic Oceans. Zoologicheski Zhurnal 112:
981-995.

Rokop, R. J. 1972. \ new species of monoplacophoran from
the abyssal North Pacific Veliger 15:91-95.

Starobogatov, Y. I. and L. I Moskalev. 1987. Systematics of
the Monoplacophora. In: Starobogatov, Y. I., A. N. Goli-
kov, and I. M. Likarev (eds.). Molluscs, results and per-
spectives of investigation. USSR, .\cadeniy of Sciences,
Zoological Institute, p. 7-11. Eight meeting on the inves-
tigation of molluscs.

Tebble, N. 1967. A Neopilina from the Gulf of .lAden. Nature,
London 215:663-664.

Tendel, O. S. 1985. Xenophyophores (Protozoa, Sarcodina)
in the diet of Neopilina galatheae (Mollusca, Monopla-
cophora). Galathea Report 1695-98.

Waren, A. 1988. Neopilina goesi, a new Caribbean mono-
placophoran mollusk dredged in 1869. Proceedings of the
Biological Society of Washington 101:671-681

Waren, A. 1989. New and little known Mollusca from Iceland.
Sarsia 74:1-28.

Waren, A. and P Bouchet. 1990. Laevipilina rolani, a new
monoplacophoran from off southwestern Europe. Journal
of Molluscan Studies 56(3):449-453

Wenz, W, 1940 Ursprung und friihe Stammesgeschichte der
Gastropoden. Archiv fiir Molluskenkvmde 72:1-10.

Wingstrand. K. G 1985. On the anatom\ and relationships
of Recent Monoplacophora. Galathea Report 16:7-94.

THE NAUTILUS 104(3): 108-1 10, 1990

Page 108

Addenda to ^'Distorsio ridens (Reeve, 1844): A Synonym of
Distorsio clathrata (Lamarck, 1816)
(Gastropoda: Personidae)"

^ illiam K. Emerson
^ alter E. Sage. Ill

Department of Imertebrates
American Museum of Natural History
New York, NY 10024-5192 USA

We are indebted to David Freeman of Cape Town, South
Africa for calling our attention (in litt.. June 6, 1990) to
an error in our recent paper pertaining to the identity
of Distorsio ridens (Reeve, 1844) (Emerson and Sage,
1990). Through an unfortunate oversight, a photograph
of the apertural view of a paralectotype of D. ridens
[British Museum (Natural History) 1967630, = D. clath-
rata (Lamarck, 1816)], which was correctly cited and
illustrated in figure 6, was inadvertently substituted for
figure 2. Figure 2 was erroneously labeled the apertural
view of the lectotype of D. ridens [American Museum
Natural History (AMNH) 6369, = D. clathrata].

The apertural view of the lectotype was previously
illustrated by Lewis (1972:45, figure 48) and an enlarge-
ment of the aperture of the lectotype was provided in
our paper (Emerson and Sage, 1990, figure 15). To cor-
rect our error, the entire view of the ventral aspect of
the lectotype is given herein to compare with Reeves
(1844, pi. 12, sp. 46) original figure of Triton ridens [=
Distorsio clathrata]. See figures 1, 2, herein.

Reference also should be made here to the two un-
identified species of Distorsio trawled in 400 m off Cape
Gardafui (Ras Asir), Somalia that were under study by
us at the time we were preparing our review of D. ridens
(Emerson and Sage, 1990:131). One of these was de-
scribed on March 31, 1990 as Distorsio somalica Parth
from "North of Mogadishou, dredged in deep water"
(Parth, 1990, figure 1; herein figures 9-12). Parth's newly
described taxon has some morphological characters that
are reminiscent of Distorsio decipiens (Reeve, 1844) and
D. reticularis (Linne, 1758) [= D. reticulata Roding 1798,
fide Beu, 1987:314]. Distorsio somalica has a larger, nar-
rower shell with more prominent labial teeth (as well as
other differing sculptural features) than that of D. de-
cipiens. Distorsio somalica resembles somewhat the gen-
eral shape of D. reticularis, but has a narrower shell with

weaker sculpture and more prominent labial teeth. In
the past D. reticularis has been confused with D. de-
cipiens (see Springsteen, 1985). Parth (1990:1), however,
compared the type specimens of D. somalica with D.
perdistorta Fulton, 1938.

The other Somalian specimens we examined are ap-
parentK referable to D. perdistorta. a wide-ranging Indo-
West Pacific species with populations also in the eastern
and western Atlantic Ocean (Beu, 1985:62). Our speci-
mens of D. perdistorta from Somalia differ from the
shells of the western-Pacific populations b\ having a wid-
er, more inflated shell, with the expanded outer lip com-
monly colored with tan rays and the parietal shield cov-
ered (in all 4 of the specimens examined) by a brightly
colored tan glaze (herein figures 3-6). The "typical" Indo-
Pacific specimens of D. perdistorta. which have a nar-
rower, less inflated, but a more distorted shell with a
whitish parietal shield, however, are also known from
off Madagascar in 300-340 meters [N. of Nossi Be, 12°43'S,
48°15'E, Academy Natural Sciences of Philadelphia
352156 (ANSP)], as reported by Lewis (1972:29). The
presence of both of these forms in the Indian Ocean
suggests that they are likely only morphs of D. perdis-
torta. Compare figures 3-6 with figures 7, 8. Distorsio
reticularis (Linne, 1758) is also known to occur in the
Indian Ocean, as noted by Parth (1990).

ACKNOWLEDGEMENTS

In addition to the courtesy extended by Mr. Freeman,
we are indebted to Mr. John Bernard of Crossville, TN
and to Dr. Gary Rosenberg of the Philadelphia .-Kcadem}-
of Sciences, PA for kindK- pro\iding us w ith the Somalian
and Madagascan specimens of Distorsio. respectiveK , for
study and report. Dr. Alan Beu of the New Zealand
Geological Survey, Lower Hutt generously contributed

Figures 1, 2. Distorsio ridens (Reeve. 1844). 1. Copy of original illustration of Triton ridens Reeve. 2. Lectotype of Triton
ridens Reeve (AMNH 6369) Figures 3-8. Distorsio perdistorta Fulton, 1938. 3-6. Off Cape Gardafui, Somalia, ex-John Bernard
Collection (3, 4. AMNH 232148: H. 6. AMNH 232147). 7, 8. North of Nossi Be, Madagascar (ANSP 352156) Figures 9-12.
Distorsio somalica Parth, 1990, same locality data as in figures 3-6 (9, 10. AMNH 232149; 11. 12. AMNH 232150) All figures
xl.

W. K. Emerson and W. E. Sage, 1990

Page 109

Page 110

THE NAUTILUS, Vol. 104, No. 3

additional data and expressed his views on the taxonomic
status of the specimens from Somalia. We also thank
Mr. Andrew Modell and Ms. Stephanie Grooms of the
.\merican Museum of Natural History who undertook
the photography and the word-processing of the manu-
script, respectively.

LITERATURE CITED

Beu, A. G. 1985. A classification and catalogue of living world
Ranellidae (= Cymatium and Bursidae). American Con-
chologist (Bulletin Conchologists of America) 13(4):.55-66.

Beu, A. G. 1987 ["1986"]. Taxonomy of gastropods of the
families Ranellidae (=Cymatiidae) and Bursidae. Part 2.
Descriptions of 14 new modern Indo-West Pacific species
and subspecies, with revisions of related taxa. New Zealand
Journal of Zoology 12(3):273-355 [published January 28,
1987, teste BeuJ

Emerson, W. K, and VV. E, Sage, III. 1990, Distorsio ridens
(Reeve, 1844); a synonym of Distorsio clathrata (Lamarck,
1816) (Gastropoda: Personidae). The Nautilus 103(4): 131-
135.

Fulton, H C. 1938. Descriptions and figures of new Japanese

marine shells. Proceedings of the Malacological Societ\ of

London 23(l):55-57.
Lewis, H. 1972. Notes on the genus Distorsio (Cymatiidae)

with descriptions of new species. The Nautilus 86(2-4):

27-50.
Linne, C. von. 1758. Systema naturae per regna tria naturae.

Editio decima, reformata. Stockholm 11-824
Parth, M, 1990. Distorsio somalica. spec, nov., ein neue Art.

aus Somalia (Gastropoda. Ranellidae). Spixiana (Miinchen)

13(l):l-3.

Reeve, L. A. 1844. Monograph of the genus Triton. Con-
chologia Iconica: or illustrations of the shells of molluscous
animals. Reeve Brothers, London, 2, Triton text and 20
pis. [T. ridens, sp. 44, pi. 12, May 1844; T. decipiens, sp.
102, pi. 20, August, 1844J

Roding, P. F. 1798. Museum Boltenianum , . pars secunda
continens Conchylia. Hamburg, i-vii. 1-199 p.

Springsteen, F. J. 1985. Distorsio decipiens (Reeve, 1844), a
valid biospecies rediscovered. Cartel Philippine Shell News
(Manila) 7(5):3-5.

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rHE NAUTILUS

Volume 104, Number 4
December 13, 1990
ISSN 0028-1344

A quarterly devoted
to malacology.

Maiiiie Biological Laboratory ..
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DEC 2 6 1990

Woods ^^■'■'«. Mass.

EDITOR-IN-CHIEF
Dr. M G. Harasewych
Division of Mollusks
National Museum of
Natural History
Smithsonian Institution
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American Malacologists, Inc.
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