SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 543 ...

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Leander by Holthuis (1950a)—and the similar-looking Periclimenes
antonbrunii—which differs most significantly from
U. urocardella in the absence of a mandibular palp—was
suggested by the discovery in the Albatross collections of an
apparently undescribed species with a vestigial mandibular
palp that otherwise appears to be closely related to P.
antonbrunii. This attempt to give greater weight to the
configuration of the carapace and rostrum than to the usually
more stable mandibular palp may prove to be premature. Some
2.
Key to Species of Urocaridella
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY
of our colleagues may contend that U. urocaridella differs from
the other two species in characters other than the presence of a
well-developed mandibular palp, such as a narrowly triangular
endpiece on the telson, more robust third maxilliped, and
different proportionate lengths of the segments of the pereopods.
It seems to us, however, that the proposal may be
defended as a possibly valid rearrangement of generic
characters that requires the involvement of no previously
unknown genera.
Telson terminating posteriorly in narrowly triangular endpiece; mandible with
well-developed 2-segmented palp; 1st pereopod with fingers longer than palm,
chela more than twice as long as carpus; 2nd pereopod with fingers considerably
longer than palm, palm longer than carpus; 3rd pereopod with propodus less than
3 times as long as dactyl; 4th and 5th pereopods with propodus less than 4 times
as long as dactyl 54. U. urocaridella
Telson with posterior margin rather simply triangular without narrow endpiece;
mandible with vestige of palp or none at all; 1st pereopod with fingers subequal to
palm in length, chela much shorter than carpus; 2nd pereopod with fingers more
or less subequal to palm in length, palm no longer than carpus; 3rd pereopod with
propodus at least 4 times as long as dactyl; 4th pereopod with propodus more than
4 times as long as dactyl; 5th pereopod with propodus more than 5 times as long
as dactyl 2
Branchiostegal spine removed from margin by at least twice length of spine; 3rd
abdominal somite with nearly subrectangular dorsal profile; 5th abdominal
pleuron rounded posteroventrally; mandible without trace of palp
U. antonbrunii (Bruce, 1967a:45)
(Comoro Islands, Japan, Great Barrier
Reef, and Palau Islands [USNM])
Branchiostegal spine removed from margin by no more than length of spine; 3rd
abdominal somite with moderately convex (not nearly subrectangular) dorsal
profile; 5th abdominal pleuron strongly acute posteroventrally; mandible with
vestigial palp *55. U. vestigialis, new species
54. Urocaridella urocaridella (Holthuis, 1950)
FIGURE 16
Urocaridella gracilis Borradaile, 1915:210 [type locality: Maldive Islands];
1917:352, pi. 53: fig. 2.—Bruce, 1990a:150.
Leander urocaridella Holthuis, 1950a:6. 28 [new name for secondary junior
homonym Leander gracilis (Borradaile)].
DIAGNOSIS.—Carapace with apex of branchiostegal spine
reaching nearly or quite as far as margin; 3rd abdominal somite
with dorsal profile nearly subrectangular, 5th abdominal
pleuron with small acute tooth at posteroventral angle; telson
terminating posteriorly in narrowly triangular endpiece; anten-
nal scale about 4 times as long as wide; mandible with
well-developed 2-segmented palp; 1st pereopod with fingers
1V2 times as long as palm, chela more than twice as long as
carpus; 2nd pereopod with fingers l 2 /3 times as long as palm,
palm distinctly longer than carpus; 3rd pereopod with propodus
2 3 A times as long as dactyl; 4th pereopod with propodus 3'A
times as long as dactyl; 5th pereopod with propodus 3 2 /3 times
as long as dactyl; maximum postorbital carapace length
probably about 5 mm.
RANGE.—Maldive Islands, northeastern India, Andaman
Islands, Mergui Archipelago, Indonesia, and New Caledonia;
littoral to 130 maters.