Periclimenes poriphilus, Bruce, 2010

Bruce, A. J., 2010, Pontoniine Shrimps (Crustacea: Decapoda: Palaemonidae) from the CReefs 2009 Heron Island Expedition, with a review of the Heron Island pontoniine fauna, Zootaxa 2541 (1), pp. 50-68 : 53-60

publication ID	https://doi.org/ 10.11646/zootaxa.2541.1.3
DOI	https://doi.org/10.5281/zenodo.5310629
persistent identifier	https://treatment.plazi.org/id/039C2F77-FFB9-FFBD-FF19-8E04B290D08E
treatment provided by	Felipe
scientific name	Periclimenes poriphilus
status	sp. nov.

Treatment

Periclimenes poriphilus View in CoL sp. nov.

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

Material examined. ovig. ♀, holotype, QM W31897 ; ♂ allotype, QM W31898 ; 1 ovig. ♀ paratype (dissected), QM W31899 ; 3♀, QM W31900 ; Heron Island reef, north-eastern side, stn HI09-076E, 23°25.990’S, 151°55.601’E, 10 m, 22 November 2009, coll. N. Bruce & K. Schnabel. GoogleMaps

Diagnosis. A small species of Periclimenes Costa of the P. diversipes species group. Rostrum straight, slender, reaching to end of antennular peduncle, dentition 6–8/1, all pre-orbital. Fourth thoracic sternite with low transverse plate without median notch. Second pereiopods unequal, dissimilar; fingers strongly gaping distally, dactyl with single small tooth proximally, fixed finger with two larger acute teeth; minor chela with fingers with 5 dactylar teeth, 3 on fixed finger, without distal gape. Ambulatory dactyl simple, not elongate; propod with single preterminal acute ventral spine, without transverse setal rows.

Description. Ovigerous female ( Fig. 2 View FIGURE 2 ). A small sized slender species of typical Periclimenes form.

Rostrum ( Fig. 3B View FIGURE 3 ) well developed, extending to end of antennular peduncle, straight, horizontal, about 0.71 of CL, dorsal carina well developed, extending onto anterior sixth of carapace, with 8 small acute equally spaced teeth, with short interdental setae, proximal tooth situated post-orbitally; ventral carina obsolete, margin straight, sparsely setose, with single small acute tooth at 0.8 of length.

Carapace ( Fig. 3A View FIGURE 3 ) smooth, glabrous, without epigastric or supraorbital spines or ridges; inferior orbital angle ( Fig. 3C View FIGURE 3 ) acute, with small inner flange; antennal spine well developed, slender, marginal, exceeding inferior orbital angle; hepatic spine ( Fig. 3D View FIGURE 3 ) well developed, similar to antennal spine, at lower level, feebly articulate, about at level of first dorsal rostral tooth; anterolateral angle of branchiostegite bluntly angular.

Abdominal segments smooth, glabrous. Third tergite not posteriorly produced, posterior margin entire. Sixth segment 0.75 of CL, 1.5 times longer than deep, 1.9 times fifth segment length; posterolateral angle acute; posteroventral angle slightly produced, semi-acute. Pleura of first three segments broadly rounded, fifth and sixth ( Fig. 2 View FIGURE 2 ) posteriorly produced, rounded.

Telson about 0.85 of CL ( Fig. 3I View FIGURE 3 ), 3.4 times longer than anterior width; lateral margins posteriorly convergent, straight, with 2 pairs of small dorsal spines, about 0.02 of telson length at 0.5 and 0.75 of telson length; posterior margin ( Fig. 3J View FIGURE 3 ) about 0.4 of anterior margin width, rounded, without median process; lateral spines small, subequal to dorsal spines; intermediate spines long, slender, about 0.25 of telson length; submedian spines shorter, robust, sparsely setulose, about 0.45 of intermediate spine length.

Antennule of normal form ( Fig. 3E View FIGURE 3 ), proximal segment about 2.0 times longer than central width, tapering slightly distally; median margin straight, setose, with small acute ventromedial tooth at about 0.3 of length; lateral margin feebly convex, sparsely setose; anterolateral margin ( Fig. 6A View FIGURE 6 ) produced with small bluntly angular medial lobe and acute lateral tooth, distinctly exceeding medial lobe, reaching to about middle of intermediate segment length; stylocerite slender, acute, reaching to about 0.5 of segment length, proximal lateral margin non-setose, statocyst normally developed, with granular statolith. Upper flagellum biramous, proximal 5 segments fused; shorter free ramus with 4 segments, about 12 groups of aesthetascs; longer ramus slender, short, filiform; lower flagellum longer, slender, filiform.

Antenna of normal form ( Fig. 3F View FIGURE 3 ); basicerite robust, with strong acute distolateral tooth. Ischiocerite and merocerite without special features. Carpocerite about 0.33 of scaphocerite length, 4.0 times longer than central width, reaching to about 0.37 of scaphocerite length. Flagellum well developed. Scaphocerite well exceeding antennular peduncle, about 0.85 of CL, 3.0 times longer than central width, tapering slightly distally; anterior margin bluntly angular; lateral margin straight, with well developed distolateral tooth, about 0.14 of scaphocerite length, at 0.77 of length.

Ophthalmic somite without median process, with small black median pigment spot.

Eye. Cornea globular ( Fig. 3G View FIGURE 3 ), oblique, diameter about 0.33 of CL, appearing whitish, poorly pigmented, with dorsal accessory spot, stalk subcylindrical, about as long as corneal diameter.

Epistome unarmed ( Fig. 4H View FIGURE 4 ), with sub-median hemispherical lateral bosses.

Labrum rounded ( Fig. 4H View FIGURE 4 ), without median carina.

Mandible ( Fig. 4A View FIGURE 4 ). Corpus slender, without palp; incisor process ( Fig. 6C View FIGURE 6 ) slender, tapering distally, obliquely truncate, with 3 acute teeth, single central tooth smallest (left) or 2 small central teeth (right), medial margin unarmed; molar process ( Fig. 6B View FIGURE 6 ) stout, subcylindrical, distally oblique, with 2 blunt teeth and numerous rows of short stout setae.

Maxillula ( Fig. 4B View FIGURE 4 ) of normal form, palp ( Fig. 6D View FIGURE 6 ) feebly bilobed, lower lobe with small ventral tubercle with minute terminal seta; upper lacinia distally rounded ( Fig. 6E View FIGURE 6 ) with about 10 stout simple spines, several simple spiniform setae, sparse plumose setae proximally; lower lacinia subcylindrical, tapering distally, with numerous simple spiniform setae.

Maxilla ( Fig. 4C View FIGURE 4 ) with flattened tapering, non-setiferous palp, about 2.5 times longer than basal width, basal endite bilobed, lobes short, dorsal lobe slightly stouter than ventral, each with about 15 slender simple terminal setae; coxal endite obsolescent, margin convex, scaphognathite well developed, about 2.8 times longer than wide, posterior lobe about 2.0 times longer than basal width, anterior lobe about 1.3 times, distally narrow, medial margin feebly concave.

First maxilliped ( Fig. 4D View FIGURE 4 ) with simple setose palp, about 4.0 times longer than wide; basal endite well developed, broadly rounded, medial margin straight, with sparse, slender simple marginal setae; coxal endite rounded, non-setose, exopod with well developed flagellum, with 4 plumose distal setae; caridean lobe large; epipod well developed, triangular, feebly bilobed.

Second maxilliped ( Fig. 4E View FIGURE 4 ) of normal form, dactylar segment about 3.0 times longer than wide, medial margin straight, densely provided with serrulate spines. Propodal segment with anterior margin broadly rounded, not medially produced, with numerous spiniform setae. Carpus, ischiomerus and basis without special features, exopod with well developed flagellum, with 4 plumose terminal setae. Coxa with medial margin convex, non-setose, with sub-rectangular epipod laterally, without podobranch.

Third maxilliped ( Fig. 4F View FIGURE 4 ) with endopod extending to slightly exceed the carpocerite. Ischiomerus completely fused with basis, combined segment bowed, about 5.5 times longer than central width, margins sub-parallel, sparsely setose disto-medially, with palisade of about 14 short submarginal plumose setae proximally, distolateral border with 3 small spinules. Basal region medially rounded, non-setose. Exopod well developed, flagellum slender, not exceeding antepenultimate segment of endopod, with 4 terminal plumose setae; penultimate endopod segment about 0.7 of antepenultimate segment length, sub-cylindrical, 5.3 times longer than central width, sparsely setose, with 5 long spiniform setae along medial margin, with sparse spiniform setae laterally; terminal segment tapering, about 4.0 times as long as basal width, with sparse long spiniform setae medially, short transverse rows of serrulate spines laterally. Coxa with small rounded medial margin, with semicircular lateral plate, without arthrobranch.

Paragnath ( Fig. 4G View FIGURE 4 ). Corpus with deep non-setose median fissure, alae narrow, somewhat pointed laterally.

Second thoracic sternite ( Fig. 3H View FIGURE 3 ) with low broad triangular median ridge; third obsolete; fourth with lower transverse ridge with small blunt submedian teeth separated by small notch; fifth with small transverse ridges laterally, posterior segments unarmed.

First pereiopod ( Fig. 5A View FIGURE 5 ) moderately slender, slightly exceeding scaphocerite carpus. Chela ( Fig. 5B View FIGURE 5 ) about 0.4 of CL; palm oval in section, tapering slightly distally, about 2.6 times longer than depth, with 4 transverse rows of short serrulate spinules proximally; fingers ( Fig. 5C View FIGURE 5 ) slender, subequal, dactyl about 0.66 of palm length, about 4.5 times longer than proximal depth, with numerous long setae, with small hooked terminal spine, cutting edges concave, laminar over distal half, entire; fixed finger similar. Carpus about 1.3 times chela length, 6.0 times longer than distal width, tapering slightly proximally, with distoventral cleaning setae; merus subequal to carpus length, subcylindrical, 6.0 times longer than width. Ischium about 0.6 of merus length, basis short, without special features. Coxa with well developed setose distoventral process ( Fig. 6F View FIGURE 6 ).

Major second pereiopod ( Fig. 5D View FIGURE 5 ) well developed. Chela ( Fig. 5E View FIGURE 5 ) slender, about 1.1 of CL. Palm subcylindrical, smooth, 3.7 times longer than depth, tapering slightly distally, fingers ( Fig. 5F View FIGURE 5 ) slender, slightly more than half palm length. Dactyl about 0.4 of palm length, slender, about 3.8 times longer than proximal depth, tapering distally to stout terminal unguis, distal half of cutting edge concave ( Fig. 6G View FIGURE 6 ), without lamina, proximal half thickened, with single strong acute tooth distally. Fixed finger ( Fig. 6G View FIGURE 6 ) with 2 large teeth distally, separated by small notch, with smaller tooth proximally, distal half biconcave, with larger deeper concavity proximally and smaller shallower concavity distally, both fingers with numerous long setae. Carpus about 0.3 of palm length, 1.7 times longer than distal width, tapering proximally, unarmed. Merus 0.73 of palm length, 5.0 times longer than width, uniform, unarmed, sparsely setose. Ischium slender, subequal to merus length, about 0.7 of palm length, 5.4 times longer than distal width, tapering slightly proximally, unarmed. Basis and coxa robust, without special features.

Minor second pereiopod ( Fig. 5G View FIGURE 5 ) smaller than major pereiopod. Chela about 1.04 of CL, 0.86 of major chela length. Palm 4.8 times longer than depth. Fingers ( Fig. 5H View FIGURE 5 ) 0.5 of palm length, slender. Dactyl 3.6 times longer than proximal depth, with stout hooked tip, proximal half of cutting edge ( Fig. 6H View FIGURE 6 ) with 2 low blunt teeth proximally, and similar tooth more distally; distal cutting edge entire, concave. Fixed finger with proximal half of cutting edge ( Fig. 6H View FIGURE 6 ) with 5 small teeth, central 3 larger than others, distal half entire, unarmed, proximally with small concavity, distally convex. Carpus 0.4 of palm length, 2.0 times longer than distal width, tapering proximally, unarmed. Merus 0.75 of palm length, 5.0 times longer than distal width, tapering slightly proximally, unarmed. Ischium slender, slightly longer than merus, basis and coxa robust, without special features.

Third pereiopod ( Fig. 5I View FIGURE 5 ) slender, slightly exceeding scaphocerite. Dactyl ( Fig. 5K View FIGURE 5 ) slender, about 0.25 of propod length, corpus and unguis clearly demarcated, unguis simple, slender, curved, about 3.5 times longer than basal width, 0.62 of corpus length, corpus compressed, about 2.0 times longer than proximal depth, dorsal margin feebly convex, ventral margin almost straight, unarmed, with paired distolateral sensory seta. Propod ( Fig. 5J View FIGURE 5 ) about 0.65 of CL, 10.0 times longer than wide, uniform, mainly sparsely setose, with single short simple distoventral spine, about 0.4 of unguis length, 0.4 of distal propod width; with single similar distal ventral spine; with numerous groups of long slender setae distally. Carpus about 0.5 of propod length, 4.0 times longer than wide, unarmed. Merus equal to 0.95 of propod length, 7.0 times longer than wide, unarmed. Ischium subequal to carpal length, 0.8 of meral length, unarmed. Basis and coxa without special features.

Fourth pereiopod similar to third, propod about 0.9 times length of third propod, spinulation and dactyl as in third pereiopod.

Fifth pereiopod similar to third. Propod about 1.2 times length of third propod, otherwise similar to third, with numerous spiniform cleaning setae; with short distoventral spine and 2 distal ventral spines, largely obscured by setae.

Uropod with protopodite posterolaterally rounded ( Fig. 3K View FIGURE 3 ). Exopod reaching well beyond telson, 2.8 times longer than broad, lateral margin straight, non-setose, with small acute distolateral tooth, with larger mobile spine medially ( Fig. 6I View FIGURE 6 ); diaeresis obsolete. Endopod about 0.9 of exopod length, 3.6 times longer than broad.

Ova small, about 40.

Male. Generally similar to female but slightly smaller and more slender.

Rostral dentition 8/1.

One second pereiopod ( Fig. 7A View FIGURE 7 ) only, chela ( Fig. 7B View FIGURE 7 ) about 1.2 times CL. Palm 3.3.times longer than deep. Dactyl ( Fig. 7C View FIGURE 7 ) 0.72 of palm length, 5.0 times longer than basal width, cutting edge mainly straight, distally concave, with small tooth at about 0.5 of length, distal cutting edge without marginal lamella, with small acute hooked tip. Fixed finger similar, proximal two-thirds straight, with small acute tooth at about half length, distal edge with minute tooth at 0.25 distally concave with laminar cutting edge. Carpus about 0.66 of palm length, 2.6 times longer than distal width, tapering proximally, unarmed. Merus 0.88 of palm length, 5.0 times longer than wide, unarmed. Ischium 1.24 times palm length, 9.0 times longer than distal width.

First pleopod ( Fig. 7D View FIGURE 7 ) with basipodite 2.3 times longer than wide, glabrous. Exopod ( Fig. 7E View FIGURE 7 ) 1.4 times longer than basipodite, 5.5 times longer than broad. Endopod 0.5 of basipodite length, with small sub-acute disto-medial accessory lobe; medial margin straight, with 3 small curved simple marginal spinules; distolateral border rounded, with sparse short plumose setae.

Second pleopod ( Fig. 7F View FIGURE 7 ) with basipodite 1.1 times first basipodite length, 2.3 times longer than broad. Exopod 1.15 times basipodite length, 4.0 times longer than wide. Endopod ( Fig. 7G View FIGURE 7 ) 0.9 of exopod length 5.3 times longer than wide, with appendices at 0.33 of medial margin length. Appendix masculina ( Fig. 7H View FIGURE 7 ) 0.28 of endopod length, subcylindrical, 6.5 times longer than wide, with 3 long simple terminal spines, longest about 0.55 of corpus length; with ventrolateral row of 4 simple spines of decreasing size proximally. Appendix interna ( Fig. 7H View FIGURE 7 ) 1.25 times length of appendix masculina with small group of cincinnuli distomedially.

Variations. Non-ovig. ♀♀, CL 1.6 mm, 1.5 mm and 1.2 mm, rostral dentitions 7/1, 6/1, 6/1 respectively.

Measurements. Holotype female: post-orbital carapace length, 1.75 mm; carapace and rostrum, 3.8 mm; total body length (approx.), 9.0 mm; major second pereiopod chela, 2.3 mm; minor second pereiopod chela, 1.9 mm; length of ovum, 0.5 mm. Allotype male: post-orbital carapace length, 1.7 mm; carapace and rostrum, 3.1 mm; total body length (approx.), 9.0 mm; major second pereiopod chela, missing; minor second pereiopod chela, 1.7 mm.

Colouration. No data.

Etymology. From pori– (Latin) from the association with a poriferan host, and φƖλíα, philia (Greek), suffix meaning attraction to.

Systematic position. Periclimenes poriphilus is a member of the Periclimenes diversipes species group, designated by Bruce (1989). This group included P. jugalis Holthuis , P. madreporae Bruce , P. diversipes Kemp , P. gonioporae Bruce , P. mahei Bruce , P. watamuae Bruce and P. difficilis Bruce. The latter is probably incorrectly placed in this group as it possesses a linguiform median plate on the fourth thoracic sternite, a feature lacking in the other species and of generic importance in some other pontoniine taxa. A key to these species is provided by Bruce (1989).

Periclimenes poriphilus most closely resembles P. gonioporae Bruce, 1983 , sharing the following features with that species: second pereiopod chelae unequal, dissimilar; fingers of major second pereiopod chela dentate, non-spatulate, with the fixed finger without a single large tooth at 0.8 of its length.

Periclimenes poriphilus may be readily distinguished from P. gonioporae by the presence of a normal, non-spatulate chela on the minor second pereiopod with proximally dentate cutting edges; and the dentition of the fingers of the major second pereiopod with a pair of robust teeth posterior to a deep preterminal concavity, unlike the single large tooth, with the distal concavity extending to the tip of the dactyl as in P. gonioporae . Also, P. poriphilus is an associate of Porifera whereas P. gonioporae is associated with scleractinian corals.

Host. Dysidea sp. , [ Dysideidae : Demospongiae] (J.N.A. Hooper, pers. com., 2 March 2010).

Remarks. The association of Periclimenes poriphila with a sponge host is of particular interest. The species of the genus Periclimenes are well known as associates with a wide variety of invertebrate hosts, including many cnidarians, molluscs, echinoderms, and a few decapod crustaceans. Only one Indo-West Pacific species, P. incertus Borradaile, 1915 , has been repeatedly reported in association with sponges. Little detail is available on the association, but specimens collected by the author have usually been found on the external surfaces of the host. Periclimenes poriphila is the first Indo-West Pacific species to have been found living in the cavity of the sponge host. The host, an undescribed species, is reported to be common on the reefs around Heron Island (J.N.A. Hooper, pers. com.).