Zosimus maculatus (De Man, 1887 )

Hsueh, Pan-Wen, 2020, New species and record of xanthid crabs (Crustacean, Decapoda) from Taiwan, Zootaxa 4809 (3), pp. 535-546 : 541-545

publication ID	https://doi.org/ 10.11646/zootaxa.4809.3.7
publication LSID	lsid:zoobank.org:pub:8FE54BBA-250D-4109-8023-1A28864A7D97
persistent identifier	https://treatment.plazi.org/id/03D9878E-833D-FFE9-FF18-FEBC422A9CC7
treatment provided by	Plazi
scientific name	Zosimus maculatus (De Man, 1887 )
status

Treatment

Zosimus maculatus (De Man, 1887) View in CoL

Figs 4 View FIGURE 4 A–G, 5A–E, 6A–H

Zosimus maculatus: Ng et al. 2008: 206 View in CoL .

Lophactaea maculate: De Man, 1887: 250 , pl. 9, fig. 1

Platypodia maculatus: Guinot 1867: 559 .

Material Examined. One specimen ( NMNS 8194-002 View Materials ), male, 30.5 by 20.6 mm, near the mouth of the Nuclear Power Plan III cooling water discharge (21°55. 87' N, 120°44.69' E), Kentin Township, Pingtung County, Taiwan, subtidal hard bottom, 8 m deep, coll. H.- T. Hong, 21 October 2014 GoogleMaps .

Description. Carapace oval, wider than long, width to length ratio about 1.48 ( Fig. 4A, B View FIGURE 4 ); dorsal surface evenly convex, regions well defined by various sizes and shapes of humps or ridges and deep grooves, mostly smooth with some granules present at edge of posterolateral margin (1R–3R), short, stiff, setae present in grooves at hepatic (1F, 2F, 1M and 2M) and branchial regions (1L–4L and1R); pattern of humps and ridges varied among regions, 2F and 1M square, with undivided hump, 2M divided into 2 uneven sized subregions, outer subregion hump with a shallow notch, humps partially connected at base of 1L–3L, 3M pentagonal, with small horizontal ridges at four lower corners, a pair of small humps with shallow grove present at center of pentagon, anterior corner of pentagon with sharp triangular hump extended to anterior of 2M, 4L with square hump, 5L and 6L with low, irregular shape of humps, fully or partially separated; 1P with a triangular hump on both margins, 2P with a triangular hump at center ( Fig. 4B View FIGURE 4 ). Front bi-lobed, separated medially by a small shallow cleft, margin about 0.3 times width of carapace, smooth and slightly arched ( Fig. 4B, C View FIGURE 4 ). Anterolateral margin flatten and arched, divided into four lobes by shallow clefts, surface smooth, shorter than posterolateral margin; posterolateral margin nearly straight ( Fig. 4B View FIGURE 4 ). Orbits well defined, supraorbital margin smooth, interrupted by a medial fissure; eyes not fully withdraw into orbital pits. Basal antennal segment rectangular, clearly separating antennular pits from orbits, flagellum short, project beyond front, antennules folding obliquely ( Fig. 4C, D View FIGURE 4 ). Third maxilliped longitudinal slender, length to width ratio about 4.50, not fully covering buccal field when closed, outer margins smooth; ischium rectangular, length to width ratio about 1.90; merus rectangular, wider than long, width to length ratio about 1.75, outer angle produced, inner angle rounded; carpus slightly inflated, approximately one-fifth as large as merus ( Fig. 4 View FIGURE 4 E–G).

Chelipeds equal in size ( Fig. 4C, E View FIGURE 4 ); merus rectangular, length to width ratio about 0.80, inner and outer surfaces covered with granules, upper and anterior margins with a longitudinal ridge, all covered with granules; carpus rectangular, length to width ratio about 1.25, anterior margins with a ridge, all covered with granules, outer surface entirely covered with granules and vermiculation of granules, forming deep vertical (upper and lower margins) and oblique (middle area) grooves, surface of each grove covered with numerous minute setae; propodus rectangular, length to width ratio about 1.50, outer margin also covered granules and vermiculation of granules, forming deep longitudinal grooves, surface of each groove also covered with numerous minute setae, lower margin of propodus thickened, smooth, anterior submarginal area with a longitudinal shallow groove extended forward to mid-region of pollex, anterior margin of upper propodus with a wide plate-like protrusion, whitish in colour; fingers subequal in size, with sharply pointed tips, blackish in colour except tips, dactylus strongly curved downward, pollex nearly straight, leaving a small gap at proximal area when closed; upper margin of dactylus with a longitudinal shallow groove on outer surface, cutting edge with 4 medium teeth, smaller distally, increasing in size toward proximal area, anterior 3 teeth wide triangular with sharp edges, 4 th tooth truncated; cutting edge of pollex with 3 large teeth and I small tooth anteriorly and a cluster of 4 minute teeth at proximal end, 2 most anterior teeth narrowed triangular, middle tooth largest and wide triangular, all 3 teeth with sharp edges, 4 th tooth smallest and truncated, cluster teeth at proximal end all triangular ( Fig. 5A, B View FIGURE 5 ).

Ambulatory legs stout, not long, strongly depressed, crested at upper, lower and anterior margins on meri, upper and anterior margins on carpi, and upper margin on propodi, grooves present between crests and raised outer surface of meri, carpi and propodi, each groove covered with numerous minute, stiff, setae; each propodus with numerous minute, stiff, setae and several long setae at basal half of lower margin; upper and lower margins of each dactylus also covered with numerous minute, stiff, setae and several long setae, claw sharp ( Fig. 5C View FIGURE 5 ).

Sternum about equal in length and width, suture between sternites 1 and 2 absent, sternites 1and 2 inclined toward body centre, surface covered with dense large granule, tip of sternites 1 with a tuft of stiff setae, dense, stiff, setae also present at suture between sternites 2 and 3, sternites 3 and 4 separated by shallow grooves curving towards abdominal cavity, surfaces of sternite 3 and anterior area of sternite 4 covered with scattered small granules, stiff setae sparsely present at suture between sternites 3 and 4 ( Fig. 5D, E View FIGURE 5 ). Male abdomen with 6 somites, dorsal surface partially covered with small to minute setae; pleonites 1 and 2 much broader than long, width to length ratio about 5.0, 3.95, respectively, pleonite 3 widest, 3–5 pleonites fused with trace of sutures, a strong raised ridge present at middle of pleonites 2 to 5, pleonite 6 square, telson semicircular, reaching to mid-region of sternum 4 ( Fig. 6A, B View FIGURE 6 ).

G1 long, slender, nearly straight at mid-region, strongly curved outwards subdistally, distal sharply tapering to sharp point, subdistal area lined with few long setae and covered with scattered small spines ( Fig. 6 View FIGURE 6 C–E); G2 short, basal segment distal end round, distal segment elongate, curved nearly perpendicular to basal segment, sharply tapering to sharp point at distal area, tip spatuliform, surface covered with dense minute to small spines ( Fig. 6 View FIGURE 6 F–H).

Colour. In life, carapace surface dark brownish with uniformly scatted yellow to orange spots, becoming beige in alcohol ( Fig. 4A, B View FIGURE 4 ).

Distribution. Ambon, Indonesia; Southern Taiwan

Remarks. The most striking feature to link the present specimen to Z. maculatus (De Man, 1887) is live colour pattern of the carapace. The live colour pattern of the present specimen agrees well with De Man’s description on colour of the type specimen: “Die Grundfarbe des Rückenschildes ist ein bräunliches Roth; die Oberfläche trägt nun eine ziemlich grosse Zahl von runden oder eirunden, gelben, weissgesäumten Flecken, und ähnliche Flecken trägt die Unterfläche nahe den Seitenrändern…” (De Man 1887; Fig. 4A View FIGURE 4 ). The other morphological characters of the present specimen are mostly in agreement with original description, but there are noticeable differences between the two specimens. For example, De Man (1887: 251) noted that the carapace surface of the type specimen is smooth and hairless, but that of the present specimen is partly granulated (i.e. 1R–3R) and covered with dense minute, stiff, setae (i.e., 1F, 2F, 1M, 2M, 1L–4L, and1R) ( Fig. 4B, C View FIGURE 4 ). Moreover, De Man (1887: 251) stated that 3L of the carapace is free from 1L and 2L but connects to rear part of 2L on right side of the carapace. In the present species, 3L is not free from 1L and 2L on either side of the carapace ( Fig. 4B View FIGURE 4 ). Lastly, the type specimen has 3 teeth on the cutting edge of the pollex, whereas the present specimen has 8 (3 large and 1 small teeth on anterior area and a cluster of 4 minute teeth at proximal area of the pollex) (De Man 1887: 252, pl. 9, fig. 1 a; Fig. 5A, B View FIGURE 5 ). These morphological variations between type and the present specimen might be due to different body size. Carapace measurements of type and the present specimen are 18 x 12 mm and 30.5 x 20.6 mm, respectively (De Man 1887: 252).