Cuapetes lanceolatus, Okuno & Chan, 2012

Okuno, Junji & Chan, Tin-Yam, 2012, A new antipatharian-associated species of the genus Cuapetes Clark, 1919 (Crustacea: Decapoda: Palaemonidae) and a new record of C. nilandensis (Borradaile, 1915) from Japan *, Zootaxa 3367 (1), pp. 115-125 : 116-121

publication ID	https://doi.org/ 10.11646/zootaxa.3367.1.11
persistent identifier	https://treatment.plazi.org/id/504387CD-FFBD-302C-FF40-F5E5FA9D6E26
treatment provided by	Felipe
scientific name	Cuapetes lanceolatus
status	sp. nov.

Treatment

Cuapetes lanceolatus View in CoL n. sp.

( Figs. 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 , 6A View FIGURE 6 )

Periclimenes sp. B . — Kawamoto & Okuno 2003: 43, unnumbered colour fig.

Kemponia sp. — Kawamoto & Okuno 2006: 43, unnumbered colour fig.

Cuapetes sp. — Kawamoto & Okuno 2009: 43, unnumbered colour fig.

M aterial examined. Holotype. RUMF-ZC-1579, female, CL 3.0 mm, Umagai , Kume Island, Ryukyu Islands, Japan, 26°21ʹ46ʹ N 126 o 51ʹ56 ʹ E, 25 m, 29 October 2002 , coll. T. Kawamoto. Paratypes. RUMF-ZC-1580, ovigerous female, CL 2.6 mm, “Mystery Hole”, Kume Island , Ryukyu Islands, 25 m, 9 August 2002 , coll. T. Kawamoto ; CMNH-ZC 02411 , female, CL 3.1 mm, NTOU M01213 View Materials , ovigerous female, CL 2.5 mm, 2 females CL 1.8 mm, 2.5 mm, same locality as holotype, 12 November 2002, coll. J. Okuno.

Description. Carapace ( Fig. 1 View FIGURE 1 ) glabrous, supraorbital spine absent; orbit feebly developed, inferior orbital angle slightly produced, bluntly angular; antennal spine well developed, slender, submarginal, arising slightly ventral to inferior orbital angle; hepatic spine narrow, arising distinctly ventral to level of antennal spine; epigastric spine present, feebly demarcated; pterygostomial margin rounded.

Rostrum ( Fig. 2A, B View FIGURE 2 ) long, narrow, straight, horizontal, 1.1–1.6 times as long as carapace, distinctly overreaching distal blade of scaphocerite; dorsal margin armed with 8–10 (usually 9) equidistant, small, acute teeth, most proximal tooth situated just above posterior orbital margin; ventral margin armed with 2–3 (usually 3) acute teeth at about midlength.

Fourth thoracic sternite ( Fig. 2C View FIGURE 2 ) with acute median process, stouter than those of congeners.

Abdomen ( Fig. 1 View FIGURE 1 ) smooth, glabrous; pleura of first to third somites broad, rounded, those of fourth and fifth posteriorly produced, but blunt; posterodorsal margin of third somite not posterodorsally produced; sixth somite moderately compressed, 0.5–0.7 times as long as carapace, subequal to telson in length, posterolateral process acute, posteroventral margin slightly produced, with small tooth. Telson ( Fig. 2D View FIGURE 2 ) slightly tapering posteriorly, posterior margin convex, with 3 pairs of spines, lateral and intermediate spines simple, intermediate spines longest, submedian spines setulose; 2 pairs of small, subequal dorsolateral spines at proximal two fifths and posterior third of telson length.

Ophthalmic somite without interocular process. Eye ( Fig. 2A View FIGURE 2 ) with large, globular cornea, accessory pigment spot absent; stalk without dorsal tubercle, distinctly longer than corneal diameter, becoming slightly narrower distally, maximum width subequal to maximum corneal diameter.

Antennular peduncle ( Fig. 2F View FIGURE 2 ) with proximal segment distinctly longer than distal two segments combined; distolateral margin slightly produced, rounded, with row of sparse setae, lateral margin straight, terminating distally in acute tooth, reaching level of proximal third of intermediate segment; ventromesial margin armed with small acute tooth; stylocerite slender, acute, reaching level of proximal two fifths of proximal segment; statocyst well developed, rounded. Intermediate segment robust, about third of proximal segment length, slightly obliquely articulated with distal segment. Distal segment slightly longer than intermediate segment, slender, non-setose. Upper flagellum ( Fig. 2E View FIGURE 2 ) biramous, proximal 15–19 segments fused, shorter free ramus 7–9 segmented; lower flagellum similar to upper flagellum in width.

Antenna with stout basicerite armed ventrolaterally with acute tooth; scaphocerite ( Fig. 2G View FIGURE 2 ) overreaching antennular peduncle, 3.7–4.5 times as long as maximum width, lateral margin feebly concave, terminating in strong tooth falling distinctly short of distal blade of bluntly angular lamella; carpocerite stout, reaching proximal fourth of scaphocerite.

Epistome unarmed.

Mandible ( Fig. 3A View FIGURE 3 ) robust, without palp; molar process truncated distally, with large, blunt teeth; incisor process tapering distally, with 3 acute distal teeth. Maxillule ( Fig. 3B View FIGURE 3 ) with feebly bilobed palp, internal lobe with small distal protuberance; upper lacinia broad, curved, distal margin truncated, with about 7 spines and sparse submarginal setae; lower lacinia tapering distally, with some spiniform setae distally. Maxilla ( Fig. 3C View FIGURE 3 ) with palp slender, tapering distally; distal endite developed, narrow, deeply bilobed, densely covered with long setae distally; proximal endite obsolete, mesial margin feebly sinuous; scaphognathite well developed, posterior lobe short, tapering distally, distal half of anterior lobe narrow, distal margin subquadrate. First maxilliped ( Fig. 3D View FIGURE 3 ) with long, slender, simple palp; distal endite with mesial margin bearing 2 rows of dense setae, rounded distally; proximal endite small, rounded, separated from distal endite by shallow notch; caridean lobe broad; exopod with welldeveloped flagellum; epipod large, subquadrate. Second maxilliped ( Fig. 3E View FIGURE 3 ) with normal endopod; dactylus broad, mesial margin slightly concave; propodus with anteromesial margin broadly rounded; carpus with distinct ventromesial process; merus about twice as long as carpus; ischium and basis fused; exopod with well developed flagellum; coxa inflated mesially; epipod oval, without podobranch. Third maxilliped ( Fig. 3F View FIGURE 3 ) with endopod slender, reaching distal third of scaphocerite, ultimate segment tapering distally, mesially with about 8 transverse rows of short setae, laterally with dense setae; penultimate segment 1.8–2.3 times as long as ultimate segment, furnished uniformly with sparse setae; antepenultimate segment clearly demarcated from basis, ventral margin sparsely setose; basis and coxa feebly demarcated, exopod with well developed flagellum, distally with long setae; coxal plate oval; small unilamellar arthrobranch present.

Branchial formula as in Table 1.

First pereiopod ( Fig. 4A View FIGURE 4 ) long, slender, overreaching distal margin of scaphocerite by length of chela and distal third of carpus. Chela ( Fig. 4B View FIGURE 4 ) 0.3–0.4 times as long as carapace; palm subcylindrical, slightly compressed, 2.3–2.7 times as long as dactylus, with 5 transverse rows of short serrulate grooming setae proximoventrally; fingers each terminating in small unguis, with numerous groups of short setae, cutting edges entire, situated slightly laterad. Carpus 0.7–0.8 times as long as carapace, 2.0–2.3 times as long as chela, slightly widened distally, with longitudinal row of serrulate grooming setae distoventrally ( Fig. 4B View FIGURE 4 ). Merus 0.6–0.7 times as long as carapace, unarmed. Ischium and coxa ventrally setose.

Second pereiopods well developed, elongate, similar in form, unequal in length. Major second pereiopod ( Fig. 4C View FIGURE 4 ) overreaching scaphocerite by combined lengths of distal fifth of merus, carpus and chela; chela 1.3–2.0 times as long as carapace, 1.9–2.7 times as long as carpus, palm 1.9–2.2 times as long as dactylus, slightly compressed, fixed finger ( Fig. 4D View FIGURE 4 ) terminating in hooked, acutely pointed unguis, cutting edge situated laterally, armed with 3 small teeth at proximal fourth and a single large tooth at midlength, remaining part entire, sharply edged; dactylus ( Fig. 4D View FIGURE 4 ) with cutting edge almost entire, armed proximally with a single large, triangular tooth; carpus slender, unarmed, feebly widened distally; merus slender, unarmed, 1.2–1.4 times as long as carpus; ischium slender, unarmed. Minor second pereiopod ( Fig. 4E View FIGURE 4 ) slightly shorter than major second pereiopod, overraching scaphocerite by lengths of carpus and chela; chela 1.1–1.3 times as long as carapace, 1.7–2.0 times as long as carpus, palm 1.7–1.9 times as long as dactylus, dactylus slightly longer than that of major second pereiopod, cutting edge almost entire, armed with a single small tooth at proximal fourth; fixed finger armed proximally with 2 small teeth, with their interspace opposing dactylar tooth; merus 1.2–1.5 times as long as carpus.

Ambulatory pereiopods rather slender, similar to each other. Third pereiopod ( Fig. 4G View FIGURE 4 ) overreaching distal margin of scaphocerite by lengths of dactylus and distal two thirds of propodus. Merus 0.8–1.0 times as long as carpus, unarmed, feebly setose. Carpus unarmed. Propodus ( Fig. 4H View FIGURE 4 ) 2.1–2.3 times as long as carpus, 6.3–10.3 times as long as dactylus, armed ventrally with 6–8 spines, dorsal surface with few short setae. Dactylus ( Fig. 4I View FIGURE 4 ) slender, curved, compressed laterally, unguis not demarcated, dorsal margin with a long seta at midlength. Fourth pereiopod overreaching distal margin of scaphocerite by lengths of dactylus, propodus and distal part of carpus, proportion similar to that of third pereiopod. Fifth pereiopod longest in all ambulatory pereiopods, overreaching distal margin of scaphocerite by lengths of dactylus and distal two thirds of propodus.

Uropod ( Fig. 2D View FIGURE 2 ) with protopodite posterolaterally produced; exopod broad, overreaching telson, subquadrate distally, lateral margin nearly straight, terminating in small acute tooth, larger, mobile spine present just mesial to distolateral tooth; endopod oval, falling slightly short of posterior margin of exopod.

Colour in life ( Fig. 6A View FIGURE 6 ). Body and appendages generally transparent, with dense red pigmentation on ventral edge of carapace, ventral midline of abdominal somites, distal part of telson, external margin of stylocerite, lateral surface of antennal basicerite, and dorsal surface of uropod. Fingers of second pereiopod pale brown, proximally ringed with pale yellow band.

Etymology. From the Latin,” lancea ”, meaning spear-like, in alluding to the general body form as well as the shape of the rostrum of the new species.

Common name. Jihuwa-tenaga-kakure-ebi (new standard Japanese name).

Distribution. So far only known from Kume Island, the Ryukyu Islands, southern Japan.

Ecological notes. The present new species was associated with an unidentified species of the genus Antipathes Pallas, 1766 (Cnidaria: Anthozoa: Hexacorallia: Antipatharia : Antipathidae ) living on the upper wall of large crevices at a depth of 25 m in Kume Island. The host black coral has a dense and intricate branching growth form (see Kawamoto & Okuno 2003, 2006, 2009).

Remarks. The present new species can be assigned to the genus Cuapetes on account of the following features: fixed hepatic spine present on the carapace; fourth thoracic sternite armed with an acute median process; mandibular palp lacking; first to third maxillipeds with developed exopodal flagella; second pereiopod elongate, exceeding scaphocerite; ambulatory pereiopods with simple dactyli and propodi bearing distoventral spines but lacking distoventral dense setae.

The lack of a supraorbital spine, eyestalk without dorsal tubercle and the absence of distoventral spines on the ischium and merus of the second pereiopod link the new species to C. akiensis ( Kubo, 1936) and C. calmani ( Tattersall, 1921) . Nevertheless, the form of the rostrum and the long upper antennular flagellum readily distinguishes the new species from these two species. In C. lanceolatus , the rostrum is straight and narrow throughout its length, and the proximal fused part of the upper flagellum of the antennule consists of 15–19 segments. In the other two species, the rostrum is proximally straight but distinctly sinuous distally, and the midlength of the rostrum is deeper than distal part. The proximal fused part of the upper flagellum of the antennule only has 5–11 segments in C. akiensis and C. calmani (see Kubo 1936; Bruce 1987). Cuapetes lanceolatus further differs from C. calmani by the terminal tooth of the external margin of the scaphocerite falling short of the distal margin of the lamella versus exceeding the lamella in C. calmani (Bruce 1987) . The ecology of C. lanceolatus also differ from C. akiensis and C. calmani with the latter two species being free living ( Bruce 2004).

In pontoniine shrimps, several genera and species are known to be associated with antipatharians (e.g., Spotte et al. 1994; d’Udekem d’Acoz 1996; Okuno 1998; Vargas 2000; Bruce 2010), although the only other Cuapetes species which does so is C. nilandensis (see below). Morphologically, C. lanceolatus can be readily separated from C. nilandensis by the lack of a supraorbital spine.

The “ Periclimenes sp. B ”, “ Kemponia sp. ” and “ Cuapetes sp. ” in Kawamoto & Okuno (2003, 2006, 2009) refer to the same colour photograph and the photographed individual is the holotype of Cuapetes lanceolatus .