Periclimenes paraleator, Li & Bruce, 2006

Li, Xinzheng & Bruce, Alexander J., 2006, Further Indo-West Pacific palaemonoid shrimps (Crustacea: Decapoda: Palaemonoidea), principally from the New Caledonian region, Journal of Natural History 40 (11 - 12), pp. 611-738 : 711-714

Periclimenes paraleator sp. nov.

( Figure 28 )

Material examined

New Caledonia: MUSORSTOM 4, stn 178, 18 ° 56.39S, 163 ° 12.99E, 520 m, 18 September 1985, 1 ovig. ♀ holotype (MNHN-Na 14945) .

Description

A medium-sized pontoniine shrimp of subcylindrical body form, very similar to Periclimenes aleator Bruce, 1991 ; both second pereiopods lost.

Carapace smooth, glabrous. Rostrum well developed, compressed, shallow, horizontal, with distinct dorsal curvature, slightly extending antennal scale, about 0.86 of carapace length; dorsal carina distinct, with seven long, acute subequal teeth along proximal 0.6 rostral length and anterior dorsal carapace, and minute subapical tooth, first tooth situated on carapace, second just above posterior orbital margin; lateral carinae feebly developed; ventral margin with four teeth on distal 0.6 ventral rostral length, first two long, similar to dorsal teeth, third tooth much smaller than first two, distal tooth subapical, minute, smaller than subapical dorsal tooth; interdental spaces and proximal ventral carina feebly setose. Supraorbital spine absent; epigastric spine situated at anterior 0.3 of the carapace length, with basal suture; orbit feebly developed, inferior orbital angle acutely produced, oval; antennal spine small, slender, marginal, distinctly below inferior orbital angle, not exceeding inferior orbital angle; hepatic spine larger than antennal spine, slender, slightly lower than antennal spine, below first dorsal rostral tooth, remote from anterior carapace margin; anterolateral angle of carapace not produced, bluntly rounded.

Abdominal segments smooth, glabrous; third abdominal segment not produced, noncarinate; pleura of first three segments broadly rounded, fourth and fifth posteriorly produced rounded, sixth segment about 1.6 times length of fifth, subcylindrical, about 1.8 times longer than deep, subuniform, posterolateral angle acute, posteroventral angle rounded. Telson about 1.62 times sixth segment length, slender, about 4.4 times longer than anterior width, lateral margins sublinear, with anterior third curved ventrally, subparallel, posterior two-thirds straight, convergent, dorsal surface with four pairs of welldeveloped dorsolateral spines at 0.39, 0.54, 0.67, and 0.84 of telson length, spines about 0.044 of telson length; posterior margin about 0.39 of anterior margin width, rounded, without acute posterior median point; posterior margin with normal three pairs of spines, lateral spines short, similar to dorsolateral spines, intermediate spines long, robust, about 0.09 of telson length, submedian spines about 0.47 of intermediate spine length.

Eye moderate large, with globular cornea, corneal diameter 0.16 of posterior orbital carapace length, without accessory pigment spot; stalk compressed, distinctly narrower than cornea in lateral view, 0.8 of corneal diameter, 1.22 times lateral width and 0.93 of dorsal maximum width.

Antennular peduncle overreaching second ventral rostral tooth; proximal segment about 2.0 times longer than central width, with slender acute stylocerite laterally, reaching to about 0.7 of segment length, anterolateral margin feebly produced, setose, with long slender acute lateral tooth reaching to about 0.6 of intermediate segment length; statocyst small; medial margin near straight, setose, with ventromedial tooth at about 0.5 of length; intermediate segment with dorsal length about 0.26 of proximal segment length, subequal to width, lateral margin expanded, setose; distal segment about 0.41 times proximal segment length, slender, about 1.75 times longer than distal width; upper flagellum biramous, with 11 proximal segments of rami fused, shorter free ramus with five segments, length about 0.42 of fused portion, total length about 0.54 of carapace length, with about 25 groups of aesthetascs; longer ramus slender, filiform, about 0.7 of carapace length; lower flagellum slender, filiform, about 0.95 times carapace length.

Antennal basicerite robust, with acute distolateral tooth; carpocerite subcylindrical, about 0.35 of scaphocerite length, 3.0 times longer than width; flagellum well developed, slender, more than 2.4 times postorbital carapace length; scaphocerite well developed, distinctly exceeding distal end of antennular peduncle, reaching beyond third ventral rostral tooth, broad, about 2.85 times longer than wide, greatest width at about 0.35 of length, distal margin bluntly rounded, distinctly exceeding distolateral tooth, lateral margin nearly straight, with strong acute distolateral tooth.

Epistome unarmed. Fourth thoracic sternite without slender median process, with broad triangular plates, separated by deep median fissure, fifth sternite similar, lateral plates smaller; posterior sternites unarmed.

Mouthparts mainly undissected. Mandible without palp; incisor process distally with three (right) or four (left) stout acute teeth, central teeth smaller than outer teeth. Third maxilliped with slender endopod, extending distally to middle of carpocerite, ischiomerus and basis fused completely, combined segment compressed, subuniform, setose medially, 6.1 times longer than central width; penultimate segment slightly compressed, about 0.57 of combined proximal segment length, with five groups of long finely spiniform setae medially; terminal segment about 0.45 of combined proximal segment length, 4.7 times longer than proximal width, distally tapering, with six transverse groups of spiniform setae ventromedially, with long distal spiniform setae; exopod with slender flagellum extending to distal end of combined proximal segment, with seven plumose setae distally; coxa with small subacute setose medial process, rounded lateral plate, arthrobranch distinct.

First pereiopods moderately slender, extending to tip of rostrum, exceeding carpocerite by chela and distal two-thirds carpus; chela with palm subcylindrical, slightly compressed, about 2.0 times longer than maximal depth, at about proximal 0.3 of length with six tranverse rows of short cleaning setae proximoventrally; fingers 0.93 of palm length, robust, tapering, surrounded by three groups of long setae medially and laterally, distally with shorter setae, cutting edges sharp, entire; carpus about 1.28 of chela length, 5.0 times longer than distal width, tapering proximally, with transverse row of serrulate setae distoventrally; merus about 1.5 times chela length, 7.4 times longer than distal width, subuniform; ichium 0.68 of chela length, 3.6 times longer than distal width, feebly carinate distoventrally, obliquely articulated with basis; basis 0.47 of chela length; coxa normal, with small, non-setose distoventral process.

Ambulatory pereiopods slender. Third pereiopod exceeds carpocerite by dactyl and propod, scaphocerite by dactyl; dactyl compressed, curved, about 0.19 of propod length, unguis distinct, about 0.51 of dorsal length of corpus, 3.64 times longer than proximal width; corpus about 2.2 times longer than proximal depth, dorsal margin feebly convex, non-setose, ventral margin largely straight, with acute distal accessory tooth, about 0.35 of unguis length, with short distolateral sensory setae; propod about 0.48 of carapace length, 10.5 times longer than maximum wide, subuniform, with pair of distoventral spines and four spines distributed along distal three-quarters ventral margin, with row of long simple setae distolaterally, and group of long simple setae distodorsally, small groups of long simple setae along ventral and dorsal margins; carpus about 0.56 of propod length, 5.1 times longer than distal width, with long produced distodorsal lobe, unarmed; merus 1.16 of propod length, 10.0 times longer than central width, uniform, unarmed; ischium 0.64 of propod length, 4.9 times longer than distal width, feebly proximally tapered; basis and coxa without special features. Fourth and fifth pereiopods similar to third, fourth propod 1.08, fifth propod 1.14 times third propod length; fifth exceeds carpocerite by dactyl and half propod.

Pleopods without special features.

Uropod distinctly exceeding distal end of extending intermediate posterior spine of telson; protopodite with posterolateral angle short, rounded; exopod 2.76 times longer than central width, lateral border distinctly convex, with small acute distal tooth, with large mobile spine medially, diaeresis distinct; endopod about 0.97 of exopod length, 3.5 times longer than wide.

Ova small, numerous, more than 300.

Measurements (mm)

Carapace length, 6.03; carapace and rostrum, 11.06; total body length (approximately), 30.1; length of ovum, 0.65.

Systematic position

Periclimenes paraleator n. sp. is very close to P. aleator Bruce, 1991 . It can be distinguished from the latter by the longer rostrum which distinctly exceeds the scaphocerite. In P. aleator , the rostrum also reaches slightly beyond the antennular peduncle. Also, the new species has a more robust body and relatively shorter ambulatory pereiopods than P. aleator . Periclimenes paraleator is also similar to P. alcocki Kemp, 1922 . It can be distinguished from the latter by the longer rostrum, larger cornea and more developed dorsolateral telson spines and the propods of ambulatory pereiopods with spinules along most ventral margin.

Etymology

Para (Greek), near, and the specific name aleator , referring to the close relationship between the two species.

Remarks

In the deep-water Periclimenes species with more than two pairs of dorsolateral telson spines, only P. albatrossae Chace and Bruce, 1993 has the rostrum exceeding the scaphocerite. Periclimenes paraleator can be distinguished immediately from that species by having only four pairs of dorsolateral telson spines. In P. albatrossae , seven pairs of those spines are present. In addition, the propod of ambulatory pereiopods in P. albatrossae is unarmed on the flexor margin.

Figures

Figure 28. Periclimenes paraleator, new species, holotype ovigerous female (MNHN-Na 14945). (a) Carapace and anterior appendages; (b) eye, dorsal view; (c) same, lateral view; (d) antennular peduncle; (e) antenna; (f) third pereiopod, propod and dactyl; (g) same, distal propod and dactyl.