Periclimenes paralcocki Li & Bruce, 2006

Bruce, A. J., 2008, Palaemonoid shrimps from the Australian north west shelf, Zootaxa 1815, pp. 1-24 : 12-14

Periclimenes paralcocki Li & Bruce, 2006

( Figs 7, 14B)

Periclimenes paralcocki Li & Bruce, 2006: 707–710 , fig 27.

Material examined. 1 ♀, CL 5.7, CMAR Cruise SS 05 2007, Imperieuse L 23 transect, 17°31’44”S 118° 50’37”E – 17°32’31”S 118°50’21”E; 407m, beam trawl, 15 June 2007, NMV J56495 .

Diagnosis: A member of the alcocki species group, rostrum not overreaching scaphocerite; dorsal rostral margin concave, dentition 8/3, first tooth epigastric, eye stalk not distinctly narrower than cornea, corneal diameter about 0.125 of carapace length, third pereiopod propod with spinules on flexor margin, and transverse setal rows and spines distally, telson with three pairs of dorsolateral spines.

Colouration ( Fig. 9B). (From colour photo). Body and appendages translucent white, rostrum and ambulatory pereiopods denser white, second pereiopod with yellowish tinge, caudal fan suffused with pink.

Remarks. The single specimen is almost complete with both first and second pereiopods and three ambulatory pereiopods, and is in good condition. The rostrum ( Fig. 7B) slightly fails to exceed the scaphocerite, is feebly concave dorsally and slightly up-turned distally, with a dentition of 8/3, dorsal carina low over most of rostral length, the proximal tooth situated over the posterior orbital margin, ventral teeth all on distal 0.4 of margin, margin mainly non-setose, with only a few submedian setae proximally. Carapace ( Fig. 7A) with the epigastric spine well separated from the posterior dorsal rostral tooth, the hepatic spine normal, well below antennal spine level and close to anterior carapace margin. The second pereiopods are markedly unequal, with palms subcylindrical finely tuberculate. The major chela ( Fig. 7C) has the fingers about 0.43 of the palm length, the dactylus ( Fig. 7 DE) is slender, compressed and laminar with a lateral expansion; the tip bears a short stout tooth, distal two thirds of cutting edge entire, proximal third with a large acute tooth distally separated by a deep notch from a smaller proximal tooth; fixed finger inflated, dentition similar to dactyl but teeth smaller, without flange. The third pereiopod ( Fig. 7G) agrees closely with that of the holotype, the propod with a pair of normal distoventral spines and a pair and three single ventral spines, with numerous long setae distolaterally; the dactyl is also similar but has paired sensory setae distolaterally on the corpus; the unguis is not demarkated. The dorsal telson spines are asymmetrical ( Fig. 7H), with four on the left and five on the right. The normal number for this species could therefore be four pairs or five pairs. Three pairs are present in the holotype but the distance between the proximal pair and the intermediate pair is double the interval between the intermediate pair and the posterior pair, suggesting that a pair of spines may be missing. In the alcocki species group, intraspecific variation in the number of dorsal telson spines can be considerable. In P. alcocki Kemp, 1922 , it has been shown to range from 2:2 to 4:5 ( Bruce, 1996).

Distribution. New to the Australian fauna and previously known only from the holotype specimen from

Bay Bayonne, Tuvalu, at a depth of 600 metres.