Periclimenaeus echinimanus, Ďuriš, Zdenĕk, Horká, Ivona & Horani, Fuad Al -, 2011

Ďuriš, Zdenĕk, Horká, Ivona & Horani, Fuad Al -, 2011, Periclimenaeus echinimanus sp. nov. (Crustacea: Decapoda: Pontoniinae), a new species from the Gulf of Aqaba, Red Sea, Zootaxa 2983, pp. 57-68 : 58-66

publication ID	https://doi.org/ 10.5281/zenodo.208057
DOI	https://doi.org/10.5281/zenodo.6185161
persistent identifier	https://treatment.plazi.org/id/03E53979-CC22-2774-D6C5-FDBDFB15FE87
treatment provided by	Plazi
scientific name	Periclimenaeus echinimanus
status	sp. nov.

Treatment

Periclimenaeus echinimanus 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 )

Type material. Marine Science Station area, Aqaba, Gulf of Aqaba, Jordan, scuba, sandy sublittoral with patch reefs, coll. Z. Ďuriš & I. Horká: (i) 1 female paratype CL 1.4 mm, MSS, coll. # Aq09-6F, 11 Jun. 2009, from dead coral, 8.7 m.— (ii) 4 spms paratypes, RMNH D.53449 (3 males CL 1.2–1.5 mm; 1 female CL 1.7 mm), coll. # Aq09-69, 2 June 2009, from grey keratose sponge about 3 cm thick, with numerous small oscula, overgrowing stone, 6 m. — (iii) 3 spms paratypes OUMNH-ZC.2011-02-060 (2 ovigerous females CL 2.4 and 2.7 mm; 1 female CL 2.4 mm), coll. # Aq09-73A, 2 June 2009, from keratose sponge growing between branches of dead part of Stylophora coral, 8 m. — (iv) 1 subadult male paratype CL 1.6 mm, OUMNH-ZC.2011-02-061, coll. # Aq 09-87I, 4 July 2009, from dead coral, 2– 4 m.— (v) 6 spms (1 male holotype CL 2.2 mm, RMNH D.53450; 1 ovigerous female allotype CL 2.2 mm, RMNH D.53451, dissected; 4 juveniles paratypes CL 0.8–1.6 mm, RMNH D.53452), coll. # Aq09-101E, 6 July 2009, from sponge growing inside dead part of Pocillopora coral, 8– 9 m.

Two remaining specimens (in addition to iii), damaged, are deposited in authors’ (ZĎ, IH) laboratory, UO.

Diagnosis. Rostral dentition 5–9/0–2, most frequently 7–8/1; supraorbital tooth present; antennal spine submarginal; scaphocerite with distolateral spine overreaching lamina; first pereiopod fingers narrowly spatulate and about one third of chela length, carpus longer than chela; second pereiopods with fingers shorter than palm, palms covered with erect slender spines on margins and medial surface, dorsal carpus and ventral merus and ischium spinose, fingers with cutting edges simple, dactylus of major chela with low plunger; ambulatory dactyli biunguiculate, ventral margins of corpus and unguis concave, with series of 4–5 denticles; first abdominal segment with anterior dorsomedian lobe; telson without posterior median process.

Description of male holotype. Small sized pontoniine shrimp of subcylindrical form ( Fig. 1 View FIGURE 1 ).

Rostrum ( Fig. 2 View FIGURE 2 A) straight, slightly turned downwards, about 0.7 of CL, height equal throughout, almost reaching end of antennular peduncle, with 9 acute dorsal teeth and two subterminal ventral teeth, ventral lamina straight, upturned distally.

Carapace ( Figs 1 View FIGURE 1 , 2 View FIGURE 2 B) smooth, without epigastric or hepatic spines; supraorbital tooth strong, conical; antennal spine well developed, distinctly submarginal, placed at level of inferior orbital angle; inferior orbital angle not produced but distinct, anterolateral margin of branchiostegite strongly produced, rounded.

Abdomen glabrous, first segment tergite with shallow but distinct anterior median lobe ( Fig. 2 View FIGURE 2 C); pleura rounded, fourth and fifth posteriorly produced, rounded, sixth segment dorsal length subequal to fifth, posterolateral and posteroventral angles subacute (malformation on left side – Fig. 2 View FIGURE 2 D).

Telson ( Fig. 2 View FIGURE 2 D) about 0.7 of CL, 2.3 times sixth segment dorsal length, 1.8 times longer than anterior width; lateral margins feebly convex, posteriorly convergent; dorsal telson spines about 0.2 of telson length, at 0.14 and 0.5 of telson length; posterior margin broadly convex without median process, lateral posterior spines small, about 0.4 of dorsal spines, intermediate spines well developed, slender, about 0.3 of telson length and 1.5 times dorsal spine length, submedian spines slender, about 0.7 of intermediate spine length, setulose.

Eyes ( Fig. 2 View FIGURE 2 B) with corneal diameter about 0.2 of CL, corneal length about half of diameter; eye without visible accessory pigmented spot; stalk short, medial length subequal to corneal diameter.

Antennule ( Fig. 2 View FIGURE 2 B) of usual form for the genus; basal peduncular segment about 2.5 times as long as central width, stylocerite broad, laterally rounded, distolateral margin slightly concave, proximally broadly rounded, and reaching distal end of second segment, medial margin with minute ventromedial tooth at about 0.5 of segment length; intermediate segment short, about 0.15 of proximal segment length, distinctly wider than long; distal segment 1.5 times longer than preceding, length slightly greater than width; upper flagellum biramous; 4–5 proximal segments fused, short ramus with 3 segments, 8 groups of long aesthetascs; longer ramus slender, with about 15 segments, lower flagellum similar, slender, with about 15 segments.

Antenna ( Fig. 2 View FIGURE 2 E) of normal form; basicerite short, laterally and dorsally unarmed; carpocerite subcylindrical, reaching about 0.7 of scaphocerite length; scaphocerite about twice longer than broad, greatest width distally, anterior margin rounded, lateral margin slightly concave, almost straight, with well developed strong distal tooth far overreaching distal margin of lamella.

Thoracic sternites narrow and without special structures.

First pereiopods ( Fig. 3 View FIGURE 3 A) slender, overreaching carpocerite by distal half of merus; chela with palm subcylindrical, about 4 times longer than deep, fingers about half of palm length, narrowly spatulate to acute tip, dactylus somewhat distally hooked, overreaching straight tip of fixed finger; carpus 1.6 times chela length, slender, about 7 times longer than distal width, tapering proximally; merus about subequal to and slightly stouter than carpus; ischium about 0. 5 of merus length, stout; basis and coxa ventrally unarmed, coxa with high dorsal lobe over articulation with basis.

Major second pereiopod ( Fig. 3 View FIGURE 3 C,D) well developed, chela about 2.5 times CL, palm 2.3 times longer than maximal depth, slightly swollen proximally, oval in section, covered with erect slender spiniform denticles ( Fig. 3 View FIGURE 3 D – detail) dorsally, ventrally, and on upper (medial) surface, latter somewhat areolate proximally by rows of spinules; outer surface with scattered low tubercles; fingers ( Fig. 3 View FIGURE 3 D) about 0.4 of palm length, sparsely setose; dactyl 2.5 times longer than maximal depth, dorsal margin broadly convex, strongly curved distally, with several spiniform denticles proximally on medial surface; tip of dactylus hooked, cutting edge with low elongate molar process in midlength, distal cutting edge concave, entire; fixed finger shorter than dactylus, tapering distally (tip broken in holotype), with fossa proximally and triangular, anteriorly directed lobe proximomedially on cutting edge; carpus about one-third of palm length, narrow proximally and expanded distally, with several sharp tubercles dorsally; merus about 0.4 of palm length, robust, twice as long as central depth, tuberculate ventrally, with produced rounded distal lobe on ventrolateral margin; ischium 0.6 of meral length, twice as long as distal depth, tapering proximally, with ventral denticles; basis and coxa short, without special features.

Minor second pereiopod ( Fig. 3 View FIGURE 3 F,G) chela of ‘shearing’ type, length about 1.5 times CL, with palm ( Fig. 3 View FIGURE 3 F) spinulose dorsally, ventrally, and on mesial surface, latter areolate proximally by rows of spinules; palm oval in section, 1.5 times longer than central depth, ventral margin convex, outer surface scarcely tuberculate; fingers about 0.7 of palm length, dactylus compressed, about 3.3 times longer than maximal depth, dorsal margin broadly convex, tip broken (hooked in other specimens examined), cutting edge simple; fixed finger basal width 1.5 times dactylus width, straight, tapering distally, tip broken (upturned, subacute in other specimens examined), cutting edge proximally grooved, with inner cutting lamina; carpus about 0.5 of palm length, stout, distally excavate, distal depth somewhat less than carpus length, dorsal surface with group of sharp denticles, ventral margin simple; merus stout, slightly longer than carpus length or half of palm length, almost twice as long as central depth, with produced rounded distal lobe on ventrolateral margin, ventrally tuberculate; ischium about 0.7 of merus length, ventral margin tuberculate; basis and coxa short, without special features.

Ambulatory pereiopods moderately robust; third pereiopod ( Fig. 4 View FIGURE 4 A) with dactylus ( Fig. 4 View FIGURE 4 B) 0.25 of propodus length, biunguiculate; unguis distinctly demarcated, 3 times longer than basal width, slightly curved, with 5 sharp ventral denticles, corpus compressed, about 2.2 times longer than deep basally, dorsal margin broadly convex, ventral margin concave, with 5 sharp, widely separated denticles and larger acute distal accessory tooth reaching to about 0.2 of unguis, accessory tooth slightly divergent from unguis; propodus about 0.6 of CL, 5.5 times longer than rather uniform width, distoventral angle armed with pair of stout spines, about 0.5 of dorsal corpus length, 10 single (one paired) spines regularly spaced along whole ventral margin; carpus as stout as propodus, tapering proximally, 0.6 of propodus length and 3.5 times longer than distal width, unarmed; merus subequal to propodus length, stouter, about 3 times longer than uniform width, ventral margin with series of widely set tubercles; ischium 0.4 of propod length, width subequal to merus width, tapering proximally, ventrally tuberculate; basis and coxa short, without special features.

Fourth pereiopod ( Fig. 4 View FIGURE 4 C,D) similar and subequal to third pereiopod, but segments slightly more slender, dactylar corpus with 4 ventral tubercles, more feebly developed, propodal spinulation reduced to 8 spines in addition to distoventral pair, merus ventrally tuberculate, ischium smooth.

Fifth pereiopod ( Fig. 4 View FIGURE 4 E,F) with segments slender in comparison to preceding legs (propodus and merus width about 0.6 of those of third pereiopod), dactylus less curved, almost straight, with unguine and corpus ventral denticles (4 on each) low but distinct, propodus lacking ventral spination except distoventral pair and single subdistal spine, merus with group of about 3 tubercles distally on ventral margin, ischium smooth.

First male pleopod with endopod ( Fig. 2 View FIGURE 2 F) 3.4 times longer than wide, medial margin straight, with 6 short slender spinules and one longer simple subterminal seta, apex and distolateral margin with 5 setulose setae, lateral margin with single short submarginal spinule at 0.4 of endopod length.

Second male pleopod with endopod bearing appendices ( Fig. 2 View FIGURE 2 G) at 0.3 of medial margin length, appendix interna far exceeding corpus of appendix masculina, with few distomedial cincinnuli, corpus of appendix masculina short, about 0.4 of appendix masculina length, 3 times longer than width, with long stout setulose terminal spiniform seta, about 4 times corpus length.

Uropods ( Fig. 2 View FIGURE 2 D) with protopodite posterolaterally unarmed; rami subequal to telson length; exopod about 2 times longer than broad, lateral margin convex, unarmed, feebly setose, with acute triangular tooth distally and adjacent feebly curved spine about twice as long as tooth; endopod ovate, 2.2 times longer than broad.

Mouthparts ( Fig. 5 View FIGURE 5 ) (allotype specimen, ovigerous female (v) ). Mandible ( Fig. 5 View FIGURE 5 A–G) without palp; incisor process ( Fig. 5 View FIGURE 5 C,F) slender with apex bearing series of 11 minute denticles in obliquely convex line; molar process ( Fig. 5 View FIGURE 5 D,G) slender, with apex truncate, subquadrate, with 3 or 4 subacute teeth at marginal angles and 2 patches of dense brushes of short setae. Mandibular asymmetry ( Fig. 5 View FIGURE 5 A,D,E,G) expressed in terminal truncation plane of molar processes, in their distal margin denticulation (3 denticles between 2 larger terminal teeth on right mandible, vs. unarmed between terminal teeth on left mandible), and in extension of setal patches on molar areas (small, widely separated patches on right mandible, vs. larger proximal patch almost reaching distal patch).

Maxillula ( Fig. 5 View FIGURE 5 H–J) with feebly bilobed palp, lower lobe short, with small spinule; upper lacinia broad, dorsal margin convex, distal margin with about 8–9 strong spines bearing series of 1–4 strong subterminal serrules on one side, and several slender spiniform setae; lower lacinia elongate, curved, tapering distally, with dense group of slender terminal and subterminal setae.

Maxilla ( Fig. 5 View FIGURE 5 K,L) with simple palp with short simple subterminal seta and tapering rounded apex, basal endite overreaching palp, deeply bilobed on right maxilla but with lobes completely fused on left maxilla, both lobes with numerous distal setae, distolateral margin of basal endite with 4 plumose setae; coxal endite obsolete, non-setose; scaphognathite normal, 4 times longer than central width, anterior lobe about 1.2 times longer than basal width, posterior lobe well developed, scaphognathite with short plumose marginal setae.

First maxilliped ( Fig. 5 View FIGURE 5 M) with elongate palp, about 5 times longer than central width, not exceeding anterior margin of basal endite, with single plumose seta on distal third of its length; basal endite with distal margin produced, rounded, medial margin rounded, with numerous spiniform setae; coxal endite divided from basal endite by shallow concavity, with several spiniform and 3 long simple setae medially; exopod with caridean lobe large, produced, overreaching distal margin of basal endite, with lateral margin broadly rounded, marginal setae plumose; flagellum subequal to caridean lobe length, flattened, with segmented-like margins and four plumose terminal setae, epipod well developed, distinctly bilobed, lobes broad, distally rounded.

Second maxilliped ( Fig. 5 View FIGURE 5 N) with normally developed endopod, dactylar segment robust, about 2.5 times longer than central width, medial margin with numerous serrulate setae; propodal segment with distomedial margin feebly produced, with 2 serrulate setae and 2 simple setae; carpus, merus and ischiobasis without special features, merus feebly divided from ischium; coxa medially rounded, with produced outer tubercle bearing single terminal seta; exopod far overreaching carpus, flattened, with segmented-like margins and four plumose terminal setae; epipod small, elongate, rounded distally, without podobranch.

Third maxilliped ( Fig. 5 View FIGURE 5 O –Q) stout, with endopod overreaching end of ischiomerus; coxa with rounded distoventral lobe, lateral plate short, broadly rounded, arthrobranch absent; basis with ventral margin rounded, ischiomerus fused to basis, without suture, combined segment about 3.8 times longer than basal width, with row of 10 short plumose setae along inner side and proximally along medial margin ( Fig. 5 View FIGURE 5 P), with long serrulate setae along distomedial margin and single small distolateral spine; penultimate segment about 0.5 of ischiomerus and basis length combined, about 3 times longer than wide, with ventromedial row of long spiniform setae; terminal segment about 0.6 of penultimate segment length, stout, tapering distally, with pair of strong terminal spines and scattered spiniform setae ventrally and on sides of ventral margin; exopod normally developed, slightly overreaching ischiomerus, flattened, with segmented-like margins ( Fig. 5 View FIGURE 5 Q) and four plumose terminal setae.

Variation. The series of 17 specimens examined exhibits some morphological variation. The rostral formula varies within the range 5–9/0–2, with the most posterior dorsal tooth being postorbital in some specimens; 7–9/ 1–2 in adults (CL over 2 mm) and 5–6/ 0–1 in juveniles up to CL 1.3 mm; the posteriormost dorsal rostral tooth is never positioned postorbitally in juveniles.

The largest specimens are the ovigerous females, with a CL of 2.2–2.7 mm and TL about 9–11 mm (iii; v), the male holotype (only complete adult male available) (v), has a CL of 2.2 mm and TL about 9.5 mm. The male appendix masculina is recognizable already in two subadult specimens at CL 1.6 mm (iv; v). Adult females are morphologically very similar to males, only the second pereiopod chelae are relatively smaller; the major chela of the largest ovigerous female (CL 2.7 mm) is about 2.2 times longer than its CL (versus 2.5 times in the holotype male).

Although the ventral rostral dentition is reduced in juveniles (absent in one specimen), supraorbital spines are well developed in them. The spinulation of the second cheliped, is sometimes less dense than in adults, but still comprises of distinct, erect spinifom denticles; only in the smallest juvenile (v: CL 0.8 mm, rostral formula 5/0) there is no trace on the supraorbital spines, and both the chelipeds are elongate, similar, equal; both being of the cutting type without a molar process/fossa structures, with the chelae surfaces smooth, lacking spiniform denticles.

The posterior telson margin lacks the median process in all specimens examined but an individual of CL 2.2 mm (iii: sex undetermined through specimen damage) possesses a minute, inconspicuous median process.

Color. Generally semitranslucent, whitish when alive, with white cornea and a wide diffuse longitudinal line on inner side of eyestalks; internal organs inside the cephalothorax somewhat purple (i), inconspicuous scattered red dots dorsally on the carapace (ii; iv), sometimes feeble spots also on chelae (iv), or easily visible dense red dots over the whole carapace and abdomen, with the female ovaria yellowish (iii – ovigerous female CL 2.7mm; iv).

Host. Unidentified sponges [Demospongia: Keratosa] ( Fig. 7 View FIGURE 7 ) growing between branches of the dead part of corals Pocillopora and Stylophora [ Scleractinia ], among branches of dead corals, or on the reef surface. Live sponge surface was grayish brown, with upturned short cylindrical oscula about 0.5-1 cm in diameter ( Fig. 7 View FIGURE 7 B,D). Sponges, or dead corals with the host sponges, were collected from depths of 2–9 m from patch reefs on a sandy sublittoral slope down from the fringing reef.

Associated fauna. In sample (ii), the host sponge was growing over a solid rock surface, and its collected part only harboured 4 specimens of the new species. In other samples, when the host sponge was growing amongst the branches of dead part of live coral, Alpheus bucephalus Coutière, 1905 , A. cf. paracrinitus Miers, 1881 , Synalpheus fossor Paulson, 1875 , S. tumidomanus ( Paulson, 1875) , Saron marmoratus ( Olivier, 1811) , Thor amboinensis ( De Man, 1888) , Exoclimenella sudanensis ( Ďuriš & Bruce, 1995) , Cuapetes spp., and gonodactylid stomatopods, were frequently or occasionally encountered.

Etymology. A combination of the Greek echinos [ἐχῖνος] (= hedgehog; sea urchin) and the Latin manus (= hand), referring to the unique erected spinules covering the chelae, like the spinose armament in sea urchins and hedgehogs.

Distribution. Known only from the type locality, Aqaba, Gulf of Aqaba, northeastern Red Sea.