Periclimenes nevillei, Bruce, 2010

Bruce, A. J., 2010, Periclimenes nevillei sp. nov. (Crustacea: Decapoda: Pontoniinae) from Vanuatu, Zootaxa 2510 (1), pp. 45-54 : 45-52

publication ID	https://doi.org/ 10.11646/zootaxa.2372.1.30
persistent identifier	https://treatment.plazi.org/id/E0212E34-8479-FF88-FF2F-F9057021FEBF
treatment provided by	Felipe
scientific name	Periclimenes nevillei
status	sp. nov.

Treatment

Periclimenes nevillei View in CoL sp. nov.

( Figs 1 –6 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 )

Material examined. Ovigerous ♀ holotype, QM W28767, 1 ♂ paratype, QM W28768, AMPI 1499 , Espiritu Santo , Vanuatu, 8 m, coll. N. Coleman, September 2004 .

Diagnosis. A small Periclimenes with rostrum well developed, straight, horizontal, with dorsal carina with 7 teeth, ventral carina with 2. Carapace without supraorbital spines, inferior orbital angle without reflected inner flange. Third abdominal segment not strongly postero-dorsally produced. Median ophthalmic process absent. Cornea well developed, globular. Fingers of first pereiopods simple, compressed. Second pereiopods well developed, subequal and similar, neither second pereiopod extremely elongate, palm smooth, fingers feebly dentate, distally entire, not proximally gaping, dactyls without lateral flange, merus without distoventral tooth. Ambulatory pereiopods with dactyl not long and slender, less than 0.25 of propod length. Telson with dorsal spines of normal size.

Description. A small sized pontoniine shrimp of subcylindrical body form.

Rostrum (female) ( Fig. 2B View FIGURE 2 ) well developed, compressed, subequal to CL, acute, slightly exceeding antennular peduncle, 1.1 times CL, dorsal carina well developed, with 7 acute teeth, decreasing in size distally, with few interdental plumose setae, ventral carina obsolete, margin feebly convex, with 2 small acute teeth at about 0.67 and 0.85 of rostral length, with numerous short plumose median setae. (♂), rostrum ( Fig. 4B View FIGURE 4 ) about 0.9 of CL, more slender, otherwise similar to female.

Carapace ( Figs 2A View FIGURE 2 , 4A View FIGURE 4 ) smooth, glabrous; with articulated epigastric spine at 0.19 of CL; without supraorbital spines or ridges; orbit obsolescent, inferior orbital angle ( Fig. 5A View FIGURE 5 ) produced, subacute, angular, with dorsal hump, without ventral flange; antennal spine well developed, marginal, exceeding inferior orbital angle; hepatic spine similar to antennal, at slightly lower level, anterior to epigastric spine level; anterolateral angle obtusely rounded.

Abdominal segments smooth, third segment tergite not posteriorly produced, without posterior marginal denticulations; sixth segment subequal to CL, twice as long as fifth, 2.4 times longer than central depth, posteroventral and posterolateral angles similar, acute; pleura broadly rounded, expanded on first 3 segments.

Telson ( Fig. 5K View FIGURE 5 ) about 0.8 of CL, 0.8 of sixth abdominal segment length, 4.0 times longer than anterior width; lateral margins sub-parallel anteriorly, convergent posteriorly, with 2 pairs of similar small submarginal dorsal spines, subequal to lateral posterior marginal spine length, at about 0.6 and 0.85 of telson length; posterior margin about 0.3 of anterior margin width, angular with central process without median point; posterior margin with lateral spines short, about 0.27 of intermediate spine length, intermediate spines long, about 0.15 of telson length, submedian spines shorter, about 0.4 of intermediate spine length, setulose.

Antennule, female ( Fig. 2C, D View FIGURE 2 ) with proximal segment about 2.4 times longer than central width, distal half tapering, medial margin setose with ventromedial tooth at half length, distolateral angle ( Fig. 5B View FIGURE 5 ) medially angularly produced, with strong acute tooth laterally; stylocerite ( Fig. 5C View FIGURE 5 ) slender, acute, reaching to about half segment length, dorsal surface with numerous long plumose setae; intermediate segment subequal to distal segment length, medial and lateral margins setose, distal segment non-setose; upper flagellum biramous, proximal 5 segments of rami fused, shorter free ramus with 2 segments, with 8 groups of aesthetascs, longer ramus filiform; lower flagellum filiform, both damaged. Male with upper rami fused for 6 segments, with 4 free segments, about 16 groups of aesthetascs.

Antenna ( Fig. 2C, E View FIGURE 2 ) with robust basicerite with acute distolateral tooth, carpocerite about 2.4 times longer than central width, slightly swollen, reaching to about half scaphocerite length, flagellum well developed, scaphocerite extending well beyond antennular peduncle, lamella 3.7 times longer than central width, lateral margin straight with strong slender tooth at 0.85 of scaphocerite length, lamella distally bluntly angular.

Epistome ( Fig. 5D View FIGURE 5 ) with larger anterior and smaller posterior rounded submedian eminences.

Ophthalmic somite without median ophthalmic process or median pigment spot.

Eye ( Fig. 2 View FIGURE 2 CF) with well developed, pigmented, globular cornea, with accessory pigment spot, diameter about 0.18 of CL; stalk subcylindrical, about 2.0 times longer than wide.

Thoracic sternites broad, increasing in width posteriorly, first, second and third maxillipeds widely separated, sternites unarmed, fourth without median process, fifth with low transverse ridges separated by median notch.

Mouthparts (male). Mandible ( Fig. 3A View FIGURE 3 ) with corpus slender, without palp; molar processes ( Fig. 5E, F View FIGURE 5 ) subcylindrical, distally truncate, with several subacute blunt marginal teeth, group of stout spiniform setae anteriorly, smaller tuft posteriorly; incisor process ( Fig. 5G View FIGURE 5 ) slender, margins sub-parallel, distally oblique with 4 well developed acute teeth, central pair only slightly smaller than medial and lateral teeth. Maxillula ( Fig. 3B View FIGURE 3 ) as usual for the genus; palp ( Fig. 5H View FIGURE 5 ) distinctly bilobed, lower lobe stouter, with small ventral tubercle bearing minute seta; upper lacinia ( Fig. 5I View FIGURE 5 ) expanded centrally, tapering distally, distal margin rounded with about 8 short stout simple spines with more slender setae; lower lacinia curved, tapering distally, with 4 stout spiniform terminal setae, numerous slender simple setae distally and marginally. Maxilla ( Fig. 3C View FIGURE 3 ) with simple tapering palp, about 3.0 times longer than basal width, with 2 short plumose setae proximolaterally; basal endite bilobed, distal lobe with 8 simple setae distally, more robust than similarly setose proximal lobe; coxal endite obsolescent, convex, non-setose; scaphocerite well developed, about 2.6 times longer than central width, anterior lobe with medial margin concave, distally rounded, posterior lobe about 0.6 of anterior lobe length. First maxilliped ( Fig. 3D View FIGURE 3 ) with slender palp, about 6.5 times longer than basal width, with short simple preterminal seta; basal and coxal endites completely fused, broad, 2.0 times longer than wide, distal margin rounded with sparse long simple setae, medial margin straight with numerous shorter spiniform setae, proximally rounded non-setose; exopod well developed with slender flagellum with 4 plumose terminal setae, caridean lobe about 2.5 times longer than central width; epipod small, feebly bilobed, cordiform. Second maxilliped ( Fig. 3E View FIGURE 3 ) of usual form for the genus, endopod with dactylar segment about 2.5 times longer than broad, with numerous stout denticulate spines medially, propodal segment distally rounded, not medially produced, with several long simple marginal spiniform setae; carpus, ischiomerus and basis without special features; exopod with slender flagellum with 4 plumose terminal setae; coxa with rounded non-setose medial boss; epipod small, suboval, without podobranch. Third maxilliped ( Fig. 3F View FIGURE 3 ) with endopod slender, reaching to about proximal end of carpocerite; ischiomerus and basis fully fused, junction feebly indicated medially, combined segment about 8.5 times longer than central width, basal region expanded, medially convex, sparsely setose, ischiomerus with numerous long simple spiniform setae medially, laterally non-setose, with submarginal ventral row of 8 very short setae on proximal medial region of ischiomerus; penultimate segment about 0.5 of proximal segment, uniform, with 8 long simple spiniform setae and few simple setae medially, subcylindrical, 5.0 times longer than wide; terminal segment 0.4 of proximal segment length, 4.0 times longer than wide, slightly swollen proximally, tapering distally with about 5 or 6 transverse rows of denticulate setae medially; exopod with slender flagellum reaching to about 0.75 of proximal endopod segment length, with 4 long plumose terminal setae; coxa medially produced, rounded, non-setose, lateral plate well developed, rounded, without arthrobranch (possibly lost in dissection).

First pereiopod ( Fig. 4C View FIGURE 4 ) slender, reaching to about middle segment of antennular peduncle, slender, chela ( Fig. 4D View FIGURE 4 ) with palm about 3.4 times longer than central depth, oval in section, with several rows of short pectinate spines proximo-medially, fingers about 0.6 of palm length, slender simple, with small, hooked tips, distal cutting edges laminar, entire; carpus 1.5 times chela length, about 8.0 times longer than distal width, with several longer pectinate spines distomedially; merus slender, subequal to carpus length, 1.5 times ischium length, basis normal; coxa with small rounded distoventral process with 3 simple spiniform terminal setae.

Second pereiopods. In female ( Fig. 2G View FIGURE 2 ), slightly unequal, similar. Major chela ( Fig. 2H View FIGURE 2 ) exceeding antennular peduncle by dactyl, chela about 0.75 of CL, palm smooth, uniform, oval in section, about 3.2 times longer than depth, dactyl ( Fig. 2I View FIGURE 2 ) about 0.5 of palm length, robust, 3.5 times longer than proximal depth, dorsal margin convex, strongly hooked unguis distally, cutting edge straight, distal half sharp, entire, with single small acute tooth at 0.3 of length, with scattered setae, fixed finger ( Fig. 2I View FIGURE 2 ) 2.0 times longer than proximal depth, slightly spatulate distally, otherwise similar to dactyl, with single small acute tooth at about 0.5 of length, carpus about 0.66 of palm length, 3.3 times longer than distal width, distally unarmed, tapering proximally, merus 0.95 of palm length, 6.2 times longer than wide, ischium 0.87 of palm length. Minor chela ( Fig. 2 View FIGURE 2 JK) reaching to end of antennular peduncle, about 0.86 of major chela length, similar to major chela, segments slightly shorter and more slender.

In male ( Fig. 4E View FIGURE 4 ), slightly unequal, major chela about 0.7 of CL, palm smooth, subcylindrical, oval in section, slightly swollen centrally, about 4.0 times longer than central depth, fingers ( Fig. 4F View FIGURE 4 ) about 0.5 of palm length, dactylus slender, compressed, about 4.0 times longer than proximal depth, tip curved with strong hooked terminal tooth, cutting edge with small blunt slightly recurved tooth at mid-length, distal cutting edge laminar, entire, fixed finger 2.4 times longer than proximal depth, similar to dactyl but with 2 small acute teeth centrally, opposite dactylar tooth, with small depression; carpus 0.7 of palm length, 4.5 times longer than distal width, tapering proximally, unarmed; merus slender, subequal to palm length, uniform, 9.0 times longer than wide, unarmed; subequal to merus length, slender, 12.5 times longer than central width, unarmed; basis and coxa without special features. Minor second pereiopod ( Fig. 4G View FIGURE 4 ) with chela 0.78 of major chela length, palm 4.0 times longer than distal width, oval in section, tapering slightly proximally, fingers ( Fig. 4H View FIGURE 4 ) 0.6 of palm length, slender, simple, with strongly hooked tips, dactyl 4.2 times longer than proximal width, cutting edge unarmed, distally laminar, fixed finger similar; carpus 1.35 times palm length, slender, 8.0 times longer than distal width; merus subequal to carpal length, ischium subequal to carpus length.

Ambulatory pereiopods slender, third pereiopod ( Figs 2L View FIGURE 2 , 4I View FIGURE 4 ) with dactyl ( Figs 2N View FIGURE 2 , 5J View FIGURE 5 ) about 0.2 of propod length, slender, about 4.0 times longer than basal width, simple, curved, with unguis poorly demarcated, about 0.75 of corpus length; propod ( Fig. 2M View FIGURE 2 ) about 0.65 of CL, 10.0 times longer than wide, with pair of short distoventral spines and pair of similar distal ventral spines, carpus half of propod length, merus subequal to propod length, ischium subequal to carpal length; fourth pereiopod similar to third, propod 1.15 times longer, with single distoventral and distal spines; fifth pereiopod 1.22 times longer than third, distally with numerous spiniform setae only.

Pleopods as usual in the genus. Male first pleopod with endopod ( Fig. 4J View FIGURE 4 ) about 3.2 times longer than wide, distally rounded, non-setose, with well developed medial accessory lobe. Second pleopod ( Fig. 4K View FIGURE 4 ) with appendices ( Fig. 4L View FIGURE 4 ) well developed, arising at 0.3 of proximal margin length, appendix masculina corpus about 7.5 times longer than wide, 0.27 of ramus length, with 2 long and 1 shorter simple terminal spiniform setae, longest spine greater than corpus length; appendix interna slender, 1.5 times length of appendix masculina, with few terminal cincinnuli.

Uropods ( Fig. 5K View FIGURE 5 ) as usual in the genus, protopodite postero-laterally unarmed; exopod about 3.8 times longer than wide, extending well beyond endopod, lateral margin straight, with short submarginal setae ventrally, ending in small acute tooth with much larger mobile spine medially ( Fig. 5N View FIGURE 5 ), with well developed complete diaeresis ( Fig. 5M View FIGURE 5 ) and large oval terminal lamina; endopod 0.8 of exopod length, about 4.0 times longer than wide, exceeding tips of posterior telson spines.

Measurements. Holotype female, postorbital carapace length, 2.3 mm; carapace and rostrum, 4.5 mm; total body length, 14.0 mm; major second pereiopod chela, 1.75 mm; minor second pereiopod chela, 1.6 mm; length of ovum, 0.5 mm. Paratype male, postorbital carapace length, 2.3 mm; carapace and rostrum, 4.5 mm; total body length, 14.0 mm; major second pereiopod chela, 1.4 mm; minor second pereiopod chela, 1.2 mm.

Etymology. Named in honour of the collector, Neville Coleman, Curator of the Australian Marine Photographic Index.

Host. Cirripathes sp. [ Antipathidae , Antipatharia ].

Colouration. (From colour photo, Fig. 6 View FIGURE 6 ). Body mainly semi-transparent, densely speckled with small yellowish-white patches; antennae and ambulatory pereiopods similar; cornea and ophthalmic somite white; eyestalk with two longitudinal white lines dorsally; hepatopancreas olive speckled with red, ovary similar, heavily marked with white; first 3 abdominal segments ventrally reddish; dorsal surface of second and third segments with transverse white bar, similar smaller narrower bars on fourth and fifth segments; caudal fan proximally white, exopod and endopod distally white.

Systematic position. Periclimenes nevillei sp. nov. is morphologically most similar to P. albolineatus Bruce & Coombes, 1997 , from which it may be distinguished by its longer rostrum (dentition 1+6/2) exceeding the antennular peduncle, with two distal ventral teeth (versus 1 + 4–5/0, shorter than antennular peduncle); inferior orbital angle strongly produced (versus feebly produced); fingers of second pereiopods not distally gaping, fixed finger with single tooth (versus fingers of second pereiopods distally gaping, fixed finger with two teeth); carpus 0.6 of palm length (versus 0.3); ambulatory propod slender, with distal and distoventral spines, sparsely setose (versus robust, non-spinose, with long setae); dactyl slender, about 0 2 of propod length, not strongly curved (versus robust, dactyl about 0.25 of propod length, strongly curved); uropodal exopod with very small distolateral tooth (versus with well developed tooth),

Remarks. Numerous popular field guides to the tropical marine life of the Indo-West Pacific region provide illustrations of Cirripathes spp. and the pontoniine and pandalid shrimps associated with these hosts, particularly Dasycaris zanzibarica Bruce, 1973 , Pontonides spp. , and Miropandalus hardingi Bruce, 1983 . Several of these species have a similar colour pattern to the host consisting of conspicuous broad transverse yellow bands, quite distinct from the colouration of P. nevillei . That this new species has not been previously observed or collected suggests that it may be relatively rare or of limited distribution.