Acmaeopleura parvula Stimpson, 1858

Naruse, Tohru, 2015, Description of a new genus and a new species of gaeticine crab (Crustacea: Brachyura: Varunidae) from the Ryukyu Islands, and a review of Acmaeopleura Stimpson, 1858, and Sestrostoma Davie & N. K. Ng, 2007, Zootaxa 3925 (2), pp. 211-228 : 218-221

publication ID	https://doi.org/ 10.11646/zootaxa.3925.2.4
publication LSID	lsid:zoobank.org:pub:A139405C-98D1-4137-97DE-645FB1D582B5
DOI	https://doi.org/10.5281/zenodo.5667356
persistent identifier	https://treatment.plazi.org/id/850887A2-F368-FF8E-FF49-FC5EFD80FAF7
treatment provided by	Plazi
scientific name	Acmaeopleura parvula Stimpson, 1858
status

Treatment

Acmaeopleura parvula Stimpson, 1858 View in CoL

( Figs. 1 View FIGURE 1 d, 2d, 3–5)

Acmaeopleura parvula Stimpson, 1858: 105 View in CoL ; 1907: 130, pl. 11, fig. 4; Bouvier 1906: 483; Balss 1922: 153; Shen 1932: figs. 99; 101; Sakai 1939: 662, pl. 75, fig. 4; Kamita 1941: 187, fig. 106; Miyake 1962: 130; Sakai 1965: 195, pl. 91, fig. 5; Kim 1973: 462, 647, fig. 199, pl. 91, fig. 152a–d; Sakai 1976: 643, pl. 220, fig. 2; Miyake 1983: 182, pl. 61-5; Kim & Jang 1987: 543; Fukui et al. 1989: 229, figs. 17, 18; Itani 2000: 69; Yamamoto et al. 2005: 12; Ng et al. 2008: 227; Machida et al. 2009: 567, pl. 2(A); Takeda et al. 2011: 70, fig. 35(152); Wada 2012: 74, fig. 4(4).

Material examined. Acmaeopleura parvula Stimpson, 1858 . Neotype: RUMF-ZC-2939, male, 6.9 × 8.5 mm, mouth of Oura River, Minami-Satsuma City, Kagoshima, Kyushu, Japan, coll. R. Maenosono, 2 Jan. 2014. Others. CBM ZC 6033, 4 males, 7.9 × 9.9–10.2 × 13.4 mm, 1 ovig. female, 9.0 × 11.6 mm, Aburatsubo, Misaki, Miura Peninsula, Japan, coll. T. Komai, 15 Mar. 2001

Description. Carapace subovate ( Figs. 3 View FIGURE 3 a, 4a) distinctly wider than long, CW 1.21–1.31 CL (mean 1.25, n = 6). Dorsal surface convex longitudinally, region poorly defined, H-shaped gastric groove discernible, covered with short, black setae near lateral margins, sidewall of posterolateral regions. Front sloping anteroventrally, frontal margin slightly convex medially in anterior view, frontal width 0.28–0.31 CW (mean 0.30, n = 6). Orbital margins entire, lined with low granules, external orbital angle weakly produced anteriorly. Infraorbital margin ending mesially with triangular, inner orbital tooth, tooth, lateral angle of front leaving wide gape between them. Male suborbital crest ( Fig. 3 View FIGURE 3 b) consists of 1 long continuous protuberance with 3 high, thick convexities on approximately middle, lateral quarter, lateral end, middle largest, lateral end smallest, lateral convexity sometime slightly apart from main protuberance; female suborbital crest ( Fig. 4 View FIGURE 4 c) continuous throughout, lined with minute granules, diminishing in size laterally. Posterior margin of pterygostomial region (anterior to Milne Edwards openings) granular. Milne Edwards openings distinct. Lateral margins of carapace entire, weakly cristate anteriorly; anterolateral margins convex; posterolateral margin straight, convergent posteriorly.

Epistome posterior margin produced medially, lined with granules.

Eyes oval, almost filling orbit ( Fig. 4 View FIGURE 4 c). Antennule with relatively high basal segment. Antenna entering orbit, with relatively short flagellum.

Thoracic sternum wide. Male thoracic sternites 2, 3 with wide, shallow depression medially ( Figs. 1 View FIGURE 1 d, 3b); female with shallower depression, anterior sternal plate of portion not covered by telson, when abdomen closed, densely covered with soft setae ( Fig. 4 View FIGURE 4 b, c). Lateral end of sternite 2 widely, weakly produced anteriorly, projection fitting concavity of third maxilliped ischium when folded ( Figs. 1 View FIGURE 1 d, 3b, 4c, 5a). Sternites 3, 4 indiscernible. Male sternoabdominal cavity moderately wide; cavity, telson reaching distal third level of cheliped bases. Simple, small granule for locking mechanism present on distal third on sternite 5. Penis sternal. Female sternoabdominal cavity not reaching suture 2/3. Vulvae apart from each other, placed posterior to base of third maxilliped ischium, adjacent to suture 5/6 on sternite 6, very short, wide sternal cover developed from posterolateral corner; operculum present.

Third maxilliped ( Figs. 1 View FIGURE 1 d, 3b, 4c, 5a) rectangular, leaving median hiatus when closed. Ischium as long as merus; ischium, merus each as long as its width, border between ischium, merus horizontal. Ischium with broad, shallow concavity on proximal margin medially, mesial margin slightly dentate, outer surface rimmed on mesial third. Merus lateral margin almost straight, mesial half of anterior margin concave, carpus attached to concave margin, outer surface rimmed over mesial third. Propodus attached to distal end of carpus, dactylus developed from subdistal portion of outer surface of propodus ( Fig. 2 View FIGURE 2 d); carpus longest, dactylus shortest; carpus, propodus trigonal-pyramid in cross-section, propodus thicker than carpus, dactylus flat, linguiform, distal end of dactylus slightly short of proximomesial corner of merus (reaching to approximately proximal quarter of mesial margin of merus) when folded ( Figs. 1 View FIGURE 1 d, 3b, 4c, 5a); long setae present on distoanterior margin of propodus, distal end of dactylus ( Fig. 2 View FIGURE 2 d); distal end of long setae reaching thoracic suture 2/3. Exopod with long flagellum, reaching distal end of carpus, with long setae on tip.

Male chelipeds subequal ( Fig. 3 View FIGURE 3 a). Merus triangular in cross-section, upper, lower-lateral, proximal portion of lower-mesial margins lined with granules, distal portion of lower-mesial margin chitinous, cristate; outer surface scattered with black short setae, lower-mesial margin with a few black, stiff, long setae. Carpus with punctate upper surface, mesial margin weakly granular, no distinct inner tooth. Chela swollen ( Fig. 3 View FIGURE 3 a, c), almost smooth except for sparsely punctate upper half of outer surface, slightly granular upper proximal margin, cluster of large granules on middle of inner surface; distinct tuft of setae on proximal third of occlusal margins of both fingers. Female chelipeds almost symmetrical ( Fig. 4 View FIGURE 4 a); chelae smaller than those of male, more densely covered with soft setae than those of male, especially on outer surface of chela.

Ambulatory legs moderately stout, P3 longest; no marginal spine or tooth. Meri longest among segments, with convex anterior, posterior margins; anterior, posterior, distal margins distinctly covered with short setae. Carpus covered with 1 or 2 wide rows of setae on upper surface, setae denser along outer margin. Propodus with reticulated setal pattern on upper surface, setae denser along outer margin. Dactylus with slightly incurved distal spine, with 3 setal rows on outer surface.

Male abdomen moderately wide ( Fig. 5 View FIGURE 5 b). First, second somites short, second, third widest, lateral margins of third to proximal two-thirds of sixth somites gradually convergent distally, third to sixth somites with sutures visible but functionally fused. Telson as long as sixth somite.

G1 ( Fig. 5 View FIGURE 5 c, d) stout, straight, distally setose, with distal chitinous short beak. G2 ( Fig. 5 View FIGURE 5 e) short, opening on distal end.

Remarks. See remarks of the genus.