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
BioStor
