Pseudoclimenes holthuisi, Bruce, 2008

Bruce, A. J., 2008, Palaemonoid shrimps from the Australian north west shelf, Zootaxa 1815, pp. 1-24 : 17-23

Pseudoclimenes holthuisi sp. nov.

( Figs 10–13)

Material examined. 1 ♀ holotype, 1 ♀ paratype, CLs 1.85, 1.6, Cruise SS 2005/10 083, Jurien Bay , 29°48’ 25”S 114°25’52”E to 29°48’53”S 114°25’55”E, 113–114m, Sherman sled, coll. G.C. Poore, 2 December 2005, NMV J55446 .

Diagnosis. As for the genus.

Description. A slenderly built pontoniine shrimp of subcylindrical body form.

Rostrum ( Fig. 11B) slender, compressed, reaching to about distal margin of intermediate segment of antennular peduncle, 0.7 of CL, dorsal carina distinct, with 7–8 small acute teeth, first two postorbital, lateral and ventral carinae obsolescent, ventral margin with numerous short plumose median setae, two small acute teeth distally, with additional minute preterminal ventral tooth in holotype.

Carapace ( Fig. 11A) smooth, glabrous, without supraorbital, epigastric, or hepatic spines, orbits obsolescent, inferior orbital angle ( Fig. 11C) broadly rounded, without ventral flange, antennal spine robust, well below inferior orbital angle, submarginal.

Abdomen with third tergite not produced or carinate, sixth segment about 1.6 of CL, 0.9 of telson length, twice as long as deep, posteroventral angle minutely acute, posterolateral angle broadly acute.

Antennule ( Fig. 11D) proximal segment of peduncle ( Fig. 11E) about 1.6 times longer than maximal width, tapering distally, medial margin straight, sparsely setose distally, with small acute ventromedial tooth at about half length, lateral margin convergent distally, concave, with small rounded distal lobe with slender divergent acute tooth laterally ( Fig. 13A), reaching well beyond adjacent lobe, statocyst normal, with granular statolith, stylocerite acute, reaching to about half segment length, intermediate and distal segments normal, combined length about 0.5 of proximal segment length, upper flagellum biramous, proximal three segments fused, upper ramus with four segments, about nine groups of aesthetascs, with long terminal group, lower ramus with ten segments.

Antenna ( Fig. 11F) normal, basicerite with small acute lateral tooth, carpocerite short, about 0.27 of scaphocerite length, subcylindrical, 2.3 times longer than wide, flagellum well developed; scaphocerite well exceeding antennular peduncle, 3.0 times longer than width, lateral margin straight, with acute distolateral tooth ( Fig. 13 AB), 0.08 of scaphocerite length, about at 0.8 of scaphocerite length, well exceeded by lamella.

Ophthalmic somite without median process or accessory pigment spot.

Eye ( Fig. 11G) with well pigmented hemispherical cornea, about 0.25 of CL, subequal to stalk width, without accessory pigment spot, stalk subcylindrical, about 1.4 times longer than width.

Epistome unarmed. Paragnaths ( Fig. 12G) with alae feebly bilobed, corpus with deep median groove.

Mandible ( Fig. 12A) corpus moderately robust, without palp; incisor process ( Fig. 13D) slender, with three acute teeth distally, lateral tooth largest, central tooth smallest; molar process ( Fig. 13C) subcylindrical, distally truncate, with five marginal teeth. Posterior tooth large and projecting, with small adjacent tufts of short simple setae.

Maxillula ( Fig. 12B) of normal form, palp ( Fig. 13E) feebly bilobed, lower lobe with small ventral tubercle with minute seta; upper lacinia ( Fig. 13F) tapering distally, rounded, with six short stout simple spines and several spiniform setae; lower lacinia subcylindrical, tapering distally, sparsely setose, with 2–3 short spiniform terminal setae and few simple setae

Maxilla ( Fig. 12C) with simple elongate non-setiferous palp; basal endite bilobed, lobes short, subequal, each with about six slender simple seta; coxal endite obsolete, medial margin rounded, non-setose; scaphog- nathite about 3.0 times longer than wide, anterior lobe 1.2 times longer than basal width, distally rounded, medially not emarginate, posterior lobe narrow, 0.8 of anterior lobe length.

First maxilliped ( Fig. 12D) with simple elongate palp with preterminal plumose seta; basal endite well developed, rounded, sparsely setose, with long simple setae, coxal endite obsolescent, convex, with single short seta only; exopod well developed with slender flagellum with four plumose terminal setae, caridean lobe normal, narrow, epipod lost in dissection.

Second maxilliped ( Fig. 12E) of normal form, endopod with dactylar segment about 4.0 times longer than wide, medial margin straight with numerous denticulate spines, propod with anteromedial margin rounded, small, with few spiniform setae, carpus, ischiomerus and basis normal, exopod well developed with slender flagellum with four plumose terminal setae, coxa with small subrectangular epipod laterally, without podobranch,

Third maxilliped ( Fig. 12F) of normal form, endopod exceeding carpocerite by terminal segment, ischiomerus feebly demarkated from basis by small margin notch, uniform, about 4.0 times longer than wide, laterally glabrous, medially with few simple setae, proximal third of medial margin with row of seven short submarginal plumose setae; penultimate segment about 0.75 of ischiomeral length, subcylindrical, 4.0 times longer than width, with pair of spiniform setae distomedially, three similar setae proximally; terminal segment about 0.8 of penultimate segment length, 4.0 times longer than proximal width, tapering distally, medial margin with five pairs of denticulate spines and similar terminal spines; exopod with slender flagellum, reaching to distal margin of ischiomerus, with four plumose terminal setae; coxa with small rounded lateral plate, medial margin not produced, non-setose; without arthrobranch.

Thoracic sternites unarmed, third with broad transverse ridge, fourth sternite without finger-like median process, with low transverse ridge without median notch.

First pereiopod ( Fig. 13G) with chela ( Fig. 13H) about 0.4 of CL, palm subcylindrical, about 1.7 times longer than deep, with three rows of short cleaning setae proximoventrally, fingers subequal to palm length, similar, sparsely setose, slender with small acute hooked tips, narrow sharp entire lamina over distal half of cutting edge; carpus short, stout, 0.79 of chela length, 3.4 times longer than distal width, tapering proximally, with several distoventral cleaning setae; merus subequal to chela length, uniform, about 6.3 times longer than wide; ischium normal, about half merus length; basis and coxa normal, coxa with small rounded ventromedial process with four short simple spiniform setae.

Second pereiopod ( Fig. 13I) small, slender; chela ( Fig. 13J) about 0.8 times CL, palm subcylindrical, smooth, about 4.0 times linger than central width, fingers ( Fig. 13K) 0.85 of palm length, dactyl slender, sparsely setose, 6.2 times longer than basal width, with acute hooked tip, cutting edge unarmed, sharp, entire over distal two thirds, fixed finger similar, tip minutely notched; carpus about 0.6 of palm length, unarmed, 2.5 times longer than distal width, tapering proximally, 1.25 times palm length, uniform, 6.5 times longer than width, unarmed; ischium about 0.8 of merus length, 5.0 times longer than distal width, tapering slightly proximally, basis and coxa without special features.

Third pereiopod of normal form, dactyl ( Fig. 13M) curved, biunguiculate, about 0.26 of propod length, unguis ( Fig. 13N) clearly demarkated, slender, about 4.0 times longer than oblique basal width, 0.63 of corpus length, corpus 3.5 times longer than basal width, dorsal margin concave, ventral margin straight with slightly preterminal slender straight accessory spine, about 0.25 of unguis length; propod ( Fig. 13 LM) about 0.57 of CL, 10.5 times longer than wide, with single or paired distoventral spine, slightly shorter than basal width of dactylar corpus, with four similar ventral spines. Fourth and fifth pereiopods similar to third.

Pleopods without special features, endopods of second pleopods without appendices masculinae.

Telson ( Fig. 11H) about 0.75 of CL, subequal to sixth segment length, 3.0 times longer than anterior width, lateral margins straight, convergent, with two pairs of submarginal dorsal spines, about 0.06 of telson length, at 0.39 and 0.68 of telson length, posterior margin about 0.4 of anterior width ( Fig. 11I) angular, without median point, with three pairs of spines, lateral spines about 0.8 of dorsal spine length, 0.28 of intermediate spine length, intermediate spines about 0.17 of telson length, submedian spines non-setulose, 0.5 of intermediate spine length.

Uropod ( Fig. 11J) with protopodite unarmed; exopod slightly exceeding endopod, 3.5 times longer than wide, lateral margin straight, with slender distolateral tooth and spine ( Fig. 13O), with sparse submarginal ventral setae; endopod about 0.85 of exopod length, 3.6 times longer than width.

Etymology. Named after Professor Lipke Bijdeley Holthuis (21 April 1921 – 8 March 2008), news of whose death was received today, in recognition of his outstanding contribution to carcinology in general and the study of the Pontoniinae in particular, and his never failing assistance to the author over half a century.

Measurements. Holotype female, postorbital carapace length, 1.85; carapace and rostrum, 3.45; total body length (approx.), 10.4, second pereiopod chela, 2.0.

Distribution. Known only from the type material.

Remarks. Apart from the lack of a hepatic spine, Pseudoclimenes holthuisi bears a close resemblance to species of the Periclimenes obscurus species group Bruce (1987; in press, 2008), particularly P. obscurus ( Kemp, 1922, fig. 15). The ambulatory dactyls in the obscurus group are generally similar, being simply biunguiculate. The accessory spines are usually slender, about half the unguis length and originate immediately adjacent to the base of the unguis, projecting more or less in the line of the unguis. In Pseudoclimenes holthuisi , the slender accessory spine is slightly remote from the base of the unguis and projects at a divergent angle to the axis of the unguis.