BULLETIN OF TIM, SOUTHERN CALIFORNIA
ACAD E M Y O I SCIENC IS
.Mini. 7, 1973
Nl Mill I' I
NEW TAXA OF BRACHYURAN CRABS FROM DIM' WATER OFF WESTERN PI Rl
AND COSTA RICA
John S. GARTH 1
Abstract: Five new species and one new genus of brachyuran crabs obtained by 1 M
del Solar and E. Fernandez-B. are described and illustrated. Of these, Homolodromia roberlsi,
Acanthocarpus delsolari, Pilumnus fernandezi, and Trizocarciniu peruvianus are most closely re-
lated to western Atlantic deep-water species, whereas. Delsolaria enriquei, a new genus and spe-
cies, is a west American endemic. The family Homolodiomiidae and ihe genera Homolodromia
and Acanthocarpus are reported for the first time from the eastern Pacific. Il is postulated
that the analogous pairs of deep-water Amphi-american species have been separated since free
communication existed at or near the depths at which they presently occur. I he Bolivar
Trench which extends across northern South America is suggested as the probable Miocene
or earlier connection.
Through the efforts of Enrique M. del Solar-C.
technical adviser to IMARPE (Instituto del Mar
del Peru), careinological collections from a
hitherto untapped source have lately found their
way into museums in the United States and
western Europe, among them the Allan Hancock
Foundation (AHF), Los Angeles, the U.S. Na-
tional Museum of Natural History (USNM),
Washington, and the Royal Netherlands Museum
(RNM), Leiden. These come from deep waters
off Peru, and are the by-product of a search for
edible shrimp and other fisheries products con-
ducted by the research vessels "Wiracocha,"
"Challua japic," and "SNP-1" under the direction
of del Solar. Independent probing of deep waters
off western Costa Rica by Hno. Eduardo
Fernandez-B., Colegio de La Salle, San Jose, has
similarly enriched the collections of the U.S.
Not only have a number of the brachyuran
species proven to be new to science, but repre-
sented among them are genera and families not
previously known to inhabit the eastern Pacific.
Four of the new species described herein have
already been mentioned in Peruvian journals (del
Solar, Blancas. and Mayta. 1970: del Solar. 1972)
with identifications to genus only, and three have
been illustrated (Chirichigno, 1970), but without
specific names. Since the genera under which
they were first reported may differ from the ones
used here, and since the published illustrations
are sometimes insufficient for species identifica-
tion, citations to the above are given for clarifica-
tion only, and are not intended to establish
priority for the species in question, which dates
solely from this publication. This paper is Allan
Hancock Foundation Contribution No. 343.
Homolodromia robertsi. new specie^
Figure 1. A-F
Type: Female, holotype, AHF No. 719. from off
Peru. lat. 03°48.5' S. long. 81°18.4' w . 800 m. 11
January 1971. mud bottom. E. M. del Solar, collector
(Orig. No. B-260). Ovigerous female, paratype.
USNM No. 141570. from off Peru. lat. 07 ; 59' S.
long. S0 C 22' \V. 800 m. 26 November 1971. hard
bottom. Trawler "Challua japic." E. M. del Solar,
collector (Orig. No. B-376).
Measurements (all in millimeters): Female holo-
type: length, including rostrum. 42.5. width
length of rostrum. 4.0. width of rostrum. 7.5, cheliped
1 Allan Hancock Foundation. Universitj
ern California. Los Angeles. Califorri