Cuapetes yapiensis, Bruce, A. J., 2013

Bruce, A. J., 2013, Cuapetes yapiensis sp. nov. (Crustacea: Decapoda: Pontoniinae), a new mangrove shrimp from Yap, Caroline Islands, Zootaxa 3737 (2), pp. 118-128 : 118-126

publication ID	https://doi.org/ 10.11646/zootaxa.3737.2.2
publication LSID	lsid:zoobank.org:pub:1B7E5C39-CB2B-4F76-9A2C-BEEDFBE36B08
DOI	https://doi.org/10.5281/zenodo.6164012
persistent identifier	https://treatment.plazi.org/id/A6378798-865C-8F37-16EE-F88EDFA4F983
treatment provided by	Plazi
scientific name	Cuapetes yapiensis
status	sp. nov.

Treatment

Cuapetes yapiensis 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. ♂ holotype QM W29188, ovig. ♀ allotype QM W29197, 7 paratypes QM W29189, stn 3, Qamun, Yap, 17 August 2001, in mangroves, coll. R. MacKenzie. 1 ovig. ♀ paratype, idem, RMNH.CRUS.D.55313. 1 ovig. ♀ paratype, idem, OUMNH.ZC. 2013 -05-004.

Diagnosis. A small species of Cuapetes , of subcylindrical body form, rostrum slender, slightly exceeding scaphocerite, dentition 1+6-8/2–3, supraorbital spines absent, without postorbital ridge, distolateral tooth of scaphocerite well exceeding lamella, second pereiopod fully developed chela with feebly or strongly dentate fingers, merus with or without acute distoventral tooth, third ambulatory dactyl about 0.35 of propod length.

Description. Paratype female, CL 2.0 mms, QM W29189. A slender shrimp, of subcylindrical body form. Rostrum ( Fig. 2 View FIGURE 2 C) well developed, slender, straight, horizontal, slightly upturned distally, about 0.95 of CL, subequal to antennular peduncle, dorsal carina feebly developed with 7 acute teeth, first tooth pre-orbital, first to fifth teeth well developed, sixth smaller, seventh minute, preterminal, lateral carinae feebly developed, ventral carina distinct, convex, with 2–3 small acute teeth, interdental spaces with median row of short plumose setae proximal to first ventral tooth, double row distally.

Carapace ( Fig. 2 View FIGURE 2 AB) smooth, glabrous, with epigastric spine at 0.3 of CL, supraorbital spines absent, without postorbital carina, antennal spine ( Fig. 5 View FIGURE 5 A) well developed, acute, marginal, well exceeding inferior orbital angle, inferior orbital angle ( Fig. 2 View FIGURE 2 C, 5A) small, acutely produced in dorsal and lateral views, with narrow medial lobe, hepatic spine well developed ( Fig. 2 View FIGURE 2 D), slightly smaller than larger antennal spine, on slightly lower level, anterolateral branchiostegite bluntly obtuse.

Abdomen with third tergite with posterior margin minutely denticulate ( Fig. 6 View FIGURE 6 H), denticulations uniform, about 0.03 mm long, sixth somite about 0.45 of CL, 1.3 times length of fifth somite, compressed, posterolateral angle well developed, acute, posteroventral angle rounded with small acute tooth ventrally, ventral margin setose, pleura of first three somites broadly rounded, fourth rounded, fifth ( Fig. 2 View FIGURE 2 H) bluntly angular, ventrally setose, fifth with minute posteroventral tooth, sixth with acute posterolateral tooth, smaller posteroventral tooth.

Telson ( Fig. 2 View FIGURE 2 I) about 0.7 of CL, about 2.5 times longer than anterior width, lateral margins sublinear, posteriorly convergent, with two pairs of subequal dorsal spines, about 0.08 of telson length, at 0.4 and 0.68 of telson length, posterior margin ( Fig. 5 View FIGURE 5 J) angular, about 0.3 of anterior width, with small acute median process ( Fig. 5 View FIGURE 5 J), lateral posterior telson spines small, shorter than dorsal spines, intermediate spines 0.34 of telson length, submedian spines slender, subventral, feebly setulose, about 0. 5 of intermediate spine length.

Antennule ( Fig. 2 View FIGURE 2 F) with peduncle slightly shorter than CL, proximal segment about 2.2 times central width, medial margin straight, setose, with small acute ventromedial tooth at 0.5 of length, distolateral angle ( Fig. 5 View FIGURE 5 B) not produced, convex, setose, with small lateral tooth, lateral margin straight, glabrous, stylocerite acute, reaching about 0.5 of medial margin length, statocyst normal; intermediate and distal segments short, subequal in length, combined length about 0.4 of proximal segment length, upper flagellum biramous, proximal 8 segments fused, short ramus single segmented with about 4 groups of aesthetascs, longer ramus with 7 segments, lower flagellum with about 25 slender segments.

Antenna ( Fig. 2 View FIGURE 2 G) with small antennal gland tubercle medially, basicerite with acute lateral tooth, carpocerite subcylindrical, short, about 2.0 times longer than wide, reaching to about 0.28 of scaphocerite length, merocerite and ischiocerite normal, short; scaphocerite ( Fig. 2 View FIGURE 2 G) well developed, well exceeding antennular peduncle and rostral tip, lamella narrow, tapering distally, rounded distally ( Fig. 5 View FIGURE 5 C), about 2.5 times longer than maximal width, lateral margin straight, with well developed, slender acute tooth distally, about 0.18 of scaphocerite length, at 0.86 of lateral margin length, well exceeding distal margin of lamella.

Ophthalmic somite without median process or median pigment spot.

Eye ( Fig. 2 View FIGURE 2 E) with well pigmented globular cornea, with dorsal accessory pigment spot, diameter about 0.21 of CL, stalk about as wide as long, length about 0.8 of corneal diameter.

Paragnath ( Fig. 6 View FIGURE 6 E) with broad robust alae, corpus short stout, tapering distally, distoventrally grooved.

Mandible ( Fig. 3 View FIGURE 3 A) robust, without palp, molar process ( Fig. 5 View FIGURE 5 DE) stout, subcylindrical, distally truncate with three stout teeth, posterior tooth broad, incisor process ( Fig. 5 View FIGURE 5 F) normal, tapering slightly distally, with three acute teeth distally, central tooth smaller than medial and lateral teeth.

Maxillula ( Fig. 3 View FIGURE 3 B) with feebly bilobed palp ( Fig. 5 View FIGURE 5 G), upper lobe slender, non-setose, lower lobe with small simple terminal setose tubercle, upper lacinia tapering, distally truncate ( Fig. 5 View FIGURE 5 H), with about 10 short stout similar simple spines and numerous spiniform setae, lower lacinia short, tapering, with numerous longer spiniform simple setae distally, several slender setae ventrally.

Maxilla ( Fig. 3 View FIGURE 3 C) with simple flattened tapering non-setose palp, about 4.0 times longer than basal width, basal endite bilobed, lobes slender, distal lobe more robust with about 12 simple setae distally, proximal lobe smaller and shorter, with about 8 distal setae, coxal endite obsolete, margin feebly convex, scaphognathite normal, anterior lobe as wide as long, posterior lobe about as long as anterior lobe, 1.5 times longer than basal width.

First maxilliped ( Fig. 3 View FIGURE 3 D) with palp similar to that of maxilla, with single long densely plumose preterminal seta, basal endite well developed, distinctly demarcated from coxal endite, distal margin rounded, medial border straight, sparsely setose with simple slender spiniform setae, coxal endite separated from basal by distinct notch, subquadrate; exopod normal, with robust flagellum with 6 long plumose terminal setae, caridean lobe small, narrow, epipod large, triangular, simple.

Second maxilliped ( Fig. 3 View FIGURE 3 E) of normal form, dactylar segment about 4.5 times longer than broad, with serrulate medial spines, propodal segment rounded anteromedially, with few stout spines and spiniform setae, carpus, merus and ischiobasis without special features, coxal endite densely setose with stout centrally swollen simple spines ( Fig. 6 View FIGURE 6 F); exopod with robust flagellum with 5 long plumose terminal setae, coxa medially produced, rounded, with long slender spines ( Fig. 6 View FIGURE 6 F), epipod small, subrectangular, without podobranch.

Third maxilliped ( Fig. 3 View FIGURE 3 F) slightly exceeding carpocerite, by length of terminal spine, with ischiomerus almost completely fused to basis, ischiomeral segment about 6.0 times longer than central width, slightly bowed and distally broadened, medial and lateral margins sub-parallel, medial margin sparsely setose, with long simple setae, distal half of lateral margin with 3 short spines, size decreasing distally, penultimate segment 0.85 of ischiomeral segment length, subcylindrical, 5.5 times longer than wide, with sparse long simple setae medially, stouter long denticulate spines laterally, terminal segment about 0.6 of penultimate segment length, 4.0 times longer than basal width, tapering distally, with short simple terminal spine, 8 groups of coarsely serrulate spiniform setae medially, exopod with robust flagellum with 5 long plumose terminal setae, coxa produced medially with small subacute process, with few simple setae ( Fig. 6 View FIGURE 6 G), lateral plate well developed, semicircular, with small 3-4 lamellar arthrobranch.

Thoracic sternites with first narrow, second and third widening, fourth broad with short median fingerlike process( Fig. 5 View FIGURE 5 I), fifth with low transverse lateral carinae separated by small median notch, posterior sternites narrow, unarmed.

First pereiopod ( Fig. 4 View FIGURE 4 A) slender, exceeding scaphocerite by fingers of chela ( Fig. 4 View FIGURE 4 B), with palm oval in section, slightly compressed, about 2.0 times as long as deep, with numerous transverse rows of cleaning setae along most of ventral palm length, fingers with sparse tufts of setae, subequal to palm length, slender, with simple hooked tips ( Fig. 4 View FIGURE 4 C), cutting edges lateral, entire, carpus slender, about 1.2 times chela length, 6.0 times longer than distal width, tapering slightly proximally; merus 0.85 of carpal length, 7.0 times longer than central width, uniform; ischium about 0.85 of chela length; basis and coxa without special features, coxa with setose ventromedial process.

Major second pereiopod ( Fig. 4 View FIGURE 4 D) with chela ( Fig. 4 View FIGURE 4 E) about 1.7 times CL, palm subcylindrical, slightly swollen centrally, smooth, 3.75 times longer than central width; fingers ( Fig. 4 View FIGURE 4 F) about 0.55 of palm length, slender, dactylus slender, 6.0 times longer than proximal depth, slightly curved with feebly hooked tip, cutting edge with two large coarse feebly bidentate teeth, separated by deep notch, on central fifth of length, proximal cutting edge with two small teeth, distal cutting edge straight, laminar, entire; proximal segments as in paratype female, merus with well developed distoventral tooth.

Minor second pereiopod similar to major but chela slimmer, fingers similar, cutting edges with similar dentition; merus with distoventral tooth.

Ambulatory pereiopod ( Fig. 4 View FIGURE 4 G) similar, slender, fourth exceeding scaphocerite by dactyl, dactyl ( Fig. 4 View FIGURE 4 I) slightly compressed, with feebly demarcated unguis, slender, curved, simple, about 8.0 times longer than basal width, 0.4 of length of dorsal margin of corpus, corpus about 4.6 times longer than proximal depth, curved, dorsal margin feebly convex, with pair of short setae at about 0.66 of length, ventral margin concave, unarmed; propod ( Fig. 4 View FIGURE 4 H) about 0.65 of CL, about 15.5 times longer than wide, uniform, with pair of slender distoventral spines, three short ventral spines; proximal segments unarmed, carpus 0.43 of propod length, 7.0 times longer than distal width, subcylindrical; merus subequal to propod length, 8.5 times longer than wide, uniform; ischium about 0.55 of propod length, 10.5 times longer than distal width, subcylindrical; basis and coxa without special features. Propod of fourth pereiopod slightly more slender than fifth propod, 1.2 times length as long.

Uropod ( Fig. 2 View FIGURE 2 K) with protopod distolaterally acute, rami well exceeding telson tip, exopod 2.4 times longer than broad, with lateral margin straight, setose, with well developed acute distolateral tooth ( Fig. 5 View FIGURE 5 K) with larger mobile spine medially, about 2.0 times tooth length, dieresis feebly developed, endopod about 0.9 of exopod length, 2.8 times longer than broad.

Ova numerous, small, about 50.

Holotype male, CL 2.5 mms, QM W29188 ( Fig. 1 View FIGURE 1 , 6 View FIGURE 6 A–B) generally very similar to female.

Rostrum with epigastric tooth and 7 dorsal, 2 ventral teeth, length subequal to CL, exceeding antennular peduncle, to distal margin of scaphocerite, distal dorsal tooth very small. Sixth abdominal segment with numerous long plumose setae along posteroventral margin, posteroventral angle with small dorsal protrusion ( Fig. 6 View FIGURE 6 B).

Major second pereiopod chela about 1.7 times CL, palm subcylindrical, slightly swollen centrally, smooth, 3.75 times longer than central width; fingers ( Fig. 6 View FIGURE 6 A) about 0.55 of palm length, slender, dactylus slender, 6.0 times longer than proximal depth, slightly curved with feebly hooked tip, cutting edge with three small acute teeth on second fourth of length, distal cutting edge straight, laminar, entire; proximal segments as in paratype female, merus with well developed distoventral tooth.

Minor second pereiopod similar to major but chela slimmer, fingers similar, cutting edges with similar dentition; merus with distoventral tooth.

Ovigerous female allotype, CL 2.0 mms, QM W29197 ( Fig. 6 View FIGURE 6 A) generally similar to above descriptions.

Rostrum with epigastric tooth and 8 dorsal, 2 ventral teeth, length subequal to CL, slightly exceeding antennular peduncle, distal dorsal tooth very small.

Second pereiopods subequal, similar, exceeding scaphocerite by carpus and chela, major chela ( Fig. 6 View FIGURE 6 C) about 1.5 times CL, palm subcylindrical, smooth, 5.9 times longer than distal depth, fingers ( Fig. 6 View FIGURE 6 D) about 0.4 of palm length, slender straight with hooked tips, about 5.0 times longer than proximal depth, proximal half of cutting edges with two large feebly bicuspid teeth separated by deep depression, distal cutting edges entire; carpus about 0.6 of palm length, lightly constricted pre-terminally and feebly expanded distally without distinct marginal teeth, tapering proximally; merus 0.72 of carpal length, with strong distoventral tooth, subcylindrical, 5.0 times longer than distal width; ischium 0.96 of meral length, 6.25 times longer than central width, unarmed, basis and coxa as in ovigerous female paratype specimen. Minor second pereiopod similar to major, slightly more slender; chela 4.33 times longer than central depth, fingers about 0.53 of palm length, similar to those of major chela, teeth slightly smaller; proximal segments as in major chela. Specimen lacks third pereiopods, distal telson and right uropodal exopod.

Male paratype, CL 1.7 mms, QM W29189 ( Fig. 6 View FIGURE 6 I–M).

Rostrum with epigastric tooth and 6 dorsal teeth, ventral margin with 2 teeth.

One major second pereiopod present, with dentate fingers separated by deep notch.

First pleopod ( Fig. 6 View FIGURE 6 I) with robust basipodite, twice as long as distal width, with single distomedial seta; exopod 1.4 times basicerite length, normal; endopod ( Fig. 6 View FIGURE 6 J) short, about 0.85 of basipodite length, proximally narrow, distal half broadly expanded, laminar with distal fourth with nine short plumose setae, central third of medial margin with pair of short hooked spinules, narrow proximal region with two medial plumose setae. Second pleopod ( Fig. 6 View FIGURE 6 K) with basipodite more robust, 2.2 times longer than wide, non-setose; exopod 1.4 times basipodite length, 3.0 times longer than wide; endopod ( Fig. 6 View FIGURE 6 L) 1.2 times basipodite length, 4.6 times longer than wide, with appendices at about half median margin length; appendix masculina ( Fig. 6 View FIGURE 6 M) robust, 0.4 of endopod length, subcylindrical, 4.0m times longer than wide, with ventral row of 11 slender simple spines and medial row of 8 spines; appendix interna slightly shorter than appendix masculina.

Variation. Rostral dentition in males (2, CLs 1.8, 2.5 mm) 1 +6/2, 1+8/3. In ovigerous females (6, CLs 1.9– 2.2 mm) 1+6/2 (1), 1+7/2 (5); non-ovigerous females (3, CLs 1.7–1.9 mm) 1+6/2 (2), 1+7/2 (1).

In holotype and allotype specimens the left and right pereiopods are subequal and similar, with strongly bidentate fingers separated by a deep notch. Only four other specimens have both second pereiopods. Two of these have dentate major chela and a simple minor chela, one has a dentate major chela and a semi-dentate minor chela and one has two with simple chelae. Nine specimens had the major chela strongly dentate and this should be regarded as normal for this species and a point of distinction from C. darwiniensis which lacks this feature.

Of the specimens with both second pereiopods one lacks a distoventral meral spine on its minor chela and one of the specimens with a single chela lacks this tooth on its minor chela.

The denticulations on the posterior margin of the third abdominal tergite are present in both male specimens, but could not be discerned in the smallest female specimen (CL 1.7 mm) or the allotype female.

Measurements (mms:) Holotype male: postorbital carapace length, 2.5; carapace and rostrum, 4.8; total body length (approx.), 11.0; major second pereiopod chela, 3.6. minor second pereiopod chela, 3.0. Allotype ovig. ♀, postorbital carapace length, 2.0; carapace and rostrum, 5.0; total body length (approx.),11.3; major second pereiopod chela, 3.2; minor second pereiopod chela, 3.3; length of ovum, 0.5.

Colour. Unknown.

Etymology. From Yap, the island of capture of these specimens, used in apposition, and – iensis (Latin), for place.

Ecology. The specimens were collected from among mangroves.