(Fig. 13)

Periclimenes antonbruunii Bruce, 1967: 45-53, Figs. 19-22; 1971b: 10.

Leandrites cyrtorhynchus Fujino & Miyake, 1969: 143-149, Figs. 1-3; Bruce, 1983a: 42.

Urocaridella antonbruunii - Chace & Bruce, 1993: 42; Bruce & Coombes, 1995: 103; Jeng, 1998: 119, photo; Debelius, 1999: 173, photo.

Material examined. – 1 female, CN R140-28, [20ºN, 108º30’E], 60m, muddy sand, AT, coll. J. Y. Liu, 9 Feb.1960.

Diagnosis. – Rostrum with 2 + 2 + 1-2/6-8 teeth, excluding the epigastric tooth on the carapace. Carapace with branchiostegal spine removed from margin by at least twice length of spine. Mandible without palp. First pereiopod with fingers subequal to palm length, chela much shorter than carpus. Second pereiopod with fingers more or less subequal to palm length, palm no longer than carpus. Third pereiopod with propodus at least 4 times as long as dactyl. Third abdominal somite with nearly subrectangular dorsal profile, 5th abdominal pleuron rounded posteroventrally. Inner pair of posterior marginal spines on telson robust, without setae.

Distribution. – Previously recorded from the Comoro Islands, Japan, Indonesia, Great Barrier Reef, and the Palau Islands. Recorded here for the first time from South China Sea.

Remarks. – Borradaile (1915) erected the genus Urocaridella, for his new species Urocaridella gracilis Borradaile, 1915. Holthuis (1950) transferred this species to Leander, because the presence of a pleurobranch at the base of the third maxilliped, and as it “shows all characters of the genus Leander ” (Holthuis, 1950: 30), and renamed this species as Leander urocaridella Holthuis, 1950 because it is a junior secondary homonym with Leander gracilis Smith, 1871. Chace & Bruce (1993) re-established the generic status of Urocaridella when describing a new species, Urocaridella vestigialis Chace & Bruce, 1993, from the Albatross collections. Their new species posesses a vestigial mandibular palp. It otherwise appears to be closely related to the pontoniine species, Periclimenes antonbruunii Bruce, 1967, in which there is no mandibular palp. They suggested to “give greater weight to the configuration of the carapace and rostrum than to the usually more stable mandibular palp” (Chace & Bruce, 1993: 42). They transferred P. antonbruunii to this genus.

These three species share many characters morphologically: their rostrum is very slender and long and strongly curved dorsally, with 2 strong dorsal teeth proximally, which curve anteriorly and bear a series of small serrations on their distal ventral margins, there are 1-3 subapical dorsal teeth; the carapace has the lower margin of the orbital angle produced anteriorly, into an oval lobe; the branchiostegal spine is situated posterior to the anterior margin of the carapace, sometimes the distance is more than 2 times the length of the spine; there is a strong tooth situated at about the midlength of the dorsal surface of the carapace (epigastric tooth); the mouthparts are very similar, except for the mandible, which appears to vary in the development of the palp from U. urocaridella (developed, 2 segments) to U. vestigialis (vestigial) to P. antonbruunii (absent); the pereiopods are subequal, slender and long. All three species have a pleurobranch at the base of third maxilliped, and 2 pairs of spines and a pair of submedian setae on the posterior margin of telson. The branchiae, consisting of one pleurobranch and one arthrobranch or 2 arthrobranchs, on the third thoracic somite, have been discussed by many authors (e.g., Borradaile, 1917; Kemp, 1922; Holthuis, 1950, 1952a, 1955, 1993; Bruce, 1986, 1993), and considered very important for distinguishing the subfamily Palaemoninae from the Pontoniinae. Borradaile (1917), as well as Kemp (1922), placed Urocaridella in the subfamily Pontoniinae, and Holthuis (1950, 1952a) transferred it to the subfamily Palaemoninae mainly on account of the branchiae associated with third maxilliped. But the status of these branchiae overlaps in some taxa between these two subfamilies (Duris & Bruce, 1995). Urocaridella sensu Chace & Bruce (1993) is a special genus, which shares some characters from the two subfamilies, e.g., the branchiae of the third maxilliped and the posterior marginal spines on the telson, but the rostrum is unique in the family Palaemonidae.