Synalpheus jinqingensis, Wang & Sha, 2015

Wang, Yan-Rong & Sha, Zhong-Li, 2015, A review of the genus Synalpheus (Crustacea: Decapoda: Caridea: Alpheidae) from China seas, Zoological Systematics 40 (4), pp. 357-435 : 390-394

Synalpheus jinqingensis sp. nov.

( Figs 23–25 )

Material examined. Holotype (MBM 283385), ♀, CL 4.6 mm, TL 12.5 mm, Jinqing Island, Xisha Islands (16°27′57″N, 111°44′17″E), 25 April 1958, coll. Zhen-Gang Fan, Jie-Shan Xu. Paratypes: (MBM 283385), 1♂, CL 4.5 mm, TL 10.5 mm, Jinqing Island, Xisha Islands (16°27′57″N, 111°44′17″E), 25 April 1958, coll. Zhen-Gang Fan, Jie-Shan Xu; (MBM 283386), 1♀, CL 4.1 mm, TL 10.5 mm, Jinqing Island, Xisha Islands (16°27′57″N, 111°44′17″E), 25 April 1958, coll. Zhen-Gang Fan, Jie-Shan Xu.

Description. Carapace smooth, glabrous; rostrum 1.7 as long as wide at base, with lateral margins slightly convex, rounded tip bearing two short setae, reaching about 2/3 length of visible part of first segment of antennular peduncle; orbital hoods about 1.5 times as wide at base as rostrum, distinctly shorter than rostrum, with rounded tip bearing two short setae; notches between orbital hoods moderately deep, V-shaped; pterygostomial corner produced into blunt acute angle.

Abdominal somites smooth, glabrous. Telson about 1.1 times as long as wide at base; lateral margin slightly concave posteriorly; dorsal surface with median groove, with two pairs of large spines, inserted approximately at 1/4 and 1/2 length of telson; posterior margin strongly convex, fringed with long setae, posterolateral angle each with two pairs of spines, lateral 1/2 length of mesial, posterolateral margins each produced into acute tooth, but distinctly shorter than lateral spine.

Eyes concealed in lateral and dorsal view.

Antennular peduncle slender, with distally acute stylocerite, latter overreaching middle of second segment of antennular peduncle, about 1/6–1/5 length of second; second segment 1.3 times as long as wide; visible part of first segment slightly longer than second, latter subequal to third. Antenna with basicerite with acute distodorsal tooth, 1/7 length of distolateral tooth, latter hardly overreaching middle of third segment, distinctly longer than stylocerite; carpocerite beyond end of antennular peduncle by 1/3 length of third segment; scaphocerite blade narrow, slightly longer than antennular peduncle, lateral spine with lateral margin slightly concave posteriorly, slightly shorter than carpocerite.

Third maxilliped far beyond antennular peduncle and carpocerite when extended; antepenultimate segment longest, about 4.6 times as long as wide; penultimate segment about 1.3 times as long as wide at base; tip of ultimate segment bearing crown of five spine-like long setae, with several brush consisting of 6–8 transverse rows of setae along ventral margin.

Major cheliped with short, stout ischium; merus 2.2 times as long as wide at base, superodistal margin ending in acute tooth; carpus cup-shaped, with long setae distodorsally; chela cylindrical, not a bit compressed or twisted, with palm about 3.2 times as long as dactylus, superodistal margin of palm almost without projecting; dactylus longer than pollex.

Minor chela with merus about 3.2 times as long as wide, longer than that of major cheliped, superodistal margin ending in acute tooth, ventral margin bearing short setae; carpus cup-shaped proportionally longer that of major cheliped; palm about 1.6 times as long as fingers; dactylus spatulate, with flexor margin slightly convex, distal three similarly teeth; pollex spatulate, with flexor surface obliquely convex, distal four teeth, with one longest, two middle and one shortest.

Second pereiopod with ischium shorter than merus; carpus five-segmented, segment ratio subequal to 4: 1: 1: 1: 2, with first segment shorter than sum of last four segment, segments 2–4 wider than long; dorsal margin of palm convex; fingers slightly shorter than palm. Third pereiopod stout; merus longer than propodus, about four times as long as wide at base, without spines on ventral margin; carpus about 1/3 merus length, with dorsal margin extended into an obtuse tooth, ventral margin with one distal spine; propodus with usual eight spines along ventral margin plus one distal pair of spines near dactylus; dactylus around 1/6 propodus length, biunguiculate, moderately slender, extensor tooth slightly longer than flexor tooth, subwide flexor tooth at base; notch between extensor and flexor tooth V-shaped. Fourth pereiopod generally similar to third; but ventral margin of carpus without distal spine. Fifth pereiopod with merus about 3.5 times as long as wide; carpus about 5/7 merus length, ventral margin without distal spine; propodus slightly shorter than merus, with one moveable spine and seven transversal rows of setae along ventral margin plus one pair of spines near dactylus.

Etymology. “jinqing” meaning the Jinqing Islalnd, the type locality of this new species.

Type locality. Jinqing Island, Xisha Islands, South China Sea.

Distribution. Xisha Islands, presently known only from the type locality in South China Sea.

Remarks. Synalpheus jinqingensis sp. nov. can be distinctly distinguished from other species by distal of spatulate dactylus and pollex of minor chela with three and four teeth, respectively. In the Indo-Pacific waters, the distal of fingers of minor chela spinform are only found in four species: S. sciro , S. pescadorensis , S. antenor , S. liui sp. nov. This new species can distinguished from above four species by the characters summarized in Table 2.

One specimen has slightly differences from others in following two ways: the stylocerite varying from the middle of the second segment to the end of that segment, the distolateral of the basicerite varying from the end of second segment to the middle of the third segment, but the stylocerite always distinctly shorter than the distolateral of the basicerite ( Fig. 25a ); the superodistal margin of the merus of minor chela (one paratype) rounded, without any projecting ( Fig. 25b ).

Figures

Fig. 23. Synalpheus jinqingensis sp. nov., female (cl 4.6mm) (MBM 283385). a–b. Frontal region. a. Dorsal. b. Lateral. c–e. Major cheliped. c. Mesial. d. Merus, lateral. e. Chela, lateral. f–h. Minor cheliped (right). f. Lateral. g. Tip of dactylus, mesial. h. Tip of dactylus and pollex. Scale bars: a–f, i–j=0.5mm; g–h=0.1 mm.

Fig. 24. Synalpheus jinqingensis sp. nov., female (cl 4.6 mm) (MBM 283385). a. Second pereiopod, lateral. b–c. Third pereiopod. b. Lateral. c. Distal propodus and dactylus, lateral. d–e. Third maxilliped. d. Dorsal. e. Tip, dorsal. f. Fourth pereiopod, lateral. g. Fifth pereiopod, lateral. h. Second pleopod. i. Telson and uropod, dorsal. Scale bars=0.5 mm.

Fig. 25. Synalpheus jinqingensis sp. nov., female (cl 4.5mm) (MBM 283385). a. Frontal region, dorsal. b. Minor cheliped, merus, lateral. Scale bars =0.5mm.