Sinodina ashima, Jiang & Zhou & Wang & Chen & Chen, 2023

Jiang, Xuankong, Zhou, Jiajun, Wang, Jianguo, Chen, Wenlong & Chen, Huiming, 2023, Description of the first stygobiotic species of the atyid shrimp genus Sinodina (Decapoda, Caridea, Atyidae) from Yunnan Province, China, ZooKeys 1186, pp. 123-137 : 123

Sinodina ashima sp. nov.

Figs 1 , 2 , 3 , 4 , 5

Type material.

Holotype: male (rl 5.1 mm, cl 5.8 mm, tl 26.7 mm), China, Yunnan Province, Kunming City, Shilin County, Xiangshuiqing Cave, 24°45′27.53″N, 103°19′54.88″E, alt. 1790 m, 4. VI. 2023, Jiang X.K. leg. Paratypes. 2 males (rl 5.0-5.9 mm, cl 6.0-6.6 mm, tl 27.5-29.5 mm) and 8 females (rl 4.6-6.5 mm, cl 5.4-6.6 mm, tl 23.5-28.7 mm), collected with holotype; 3 females (rl 5.7-9.0 mm, cl 6.7-8.2 mm, tl 28.9-40.0 mm), same locality, III. 2023, Zhou J.J. leg.

Diagnosis.

Body color and eyes strongly degenerated. Rostrum extremely elongated and upturned, obviously beyond end of scaphocerite, rostral formula: 7-11 + 14-15/8-14. Male propodus of third and fourth pereiopod normal without dilation. Dactylus of third pereiopod with 4-6 spinules. Telson with 6-7 pairs of dorsal spines.

Description.

Body slender (Fig. 1 ). Rostrum long, slightly to strongly upturned (Fig. 2 ), reaching obviously beyond end of scaphocerite, 0.85-1.1 times of cl, armed dorsally with 22-26 (holotype 23) teeth, including 7-11 (holotype 8) situated posterior to orbital margin, ventrally with 8-14 (holotype 11) teeth, rostral formula: 7-11 + 14-15/8-14 (Figs 1 - 3A ).

Eyes small, highly reduced, without ocular peduncle, only centre of cornea slightly pigmented (Figs 1 - 3A ).

Carapace smooth, glabrous, antennal spine acute, pterygostomian margin subrectangular, pterygostomian spine absent (Figs 1 - 3A ).

Antennule (Fig. 3C ) peduncle three-segmented, c. 0.6 times as long as carapace. Basal segment about 1.5 times as long as second and 2.0 times as long as third. All segments with submarginal setae. Stylocerite almost reaching end of basal segment. Anterolateral angle reaching one third of 2nd segment. Flagella long and simple.

Antennal (Fig. 3D ) peduncle about 0.4 length of scaphocerite. Scaphocerite about 3.0 times as long as wide, outer margin straight, asetose, ending in a strong sub-apical spine, inner and anterior margins with long plumose setae.

Mandible incisor process with six irregular and blunt teeth. Molar process truncated (Fig. 3B ).

Maxillula (Fig. 3E ) lower lacinia broadly rounded, with several rows of plumose setae. Upper lacinia elongate, with numerous small teeth and short setae on inner margin. Palp digitiform, slightly expanded distally, with few long setae.

Maxilla (Fig. 3F ) with palp slender and slightly curved. Upper endites subdivided. Scaphognathite tapering posteriorly with some long, curved setae.

First maxilliped (Fig. 3G ) epipod small. Palp rounded, with several terminal plumose setae. Exopod flagellum distinct, well developed and with plumose marginal setae. Caridean lobe narrow, with dense plumose marginal setae.

Second maxilliped (Fig. 3H ) slender. Ultimate and penultimate segments of endopod fused. Inner margin of ultimate, penultimate and basal segments with long straight setae. Exopod long and slender, with several plumose setae distally. Podobranch simple.

Third maxilliped (Fig. 4A ) endopod three-segmented, basal segment about 7 times as long as broad, second segment about 10 times as long as broad and 0.95 times as long as basal segment, distal segment as long as second segment, ending in small claw-like apical spine surrounded by simple setae, preceded by 7 spines along distal third of posterior margin, a clump of long and simple setae proximally. Exopod reaching beyond end of basal segment of endopod, with long plumose setae distally.

First pereiopod (Fig. 4B ) stout, chela about 1.8 times as long as wide, 0.9 times length of carpus, movable finger about 2.8 times as long as wide, and 1.2 times length of palm, fingertips rounded, with numerous long setae. Carpus excavated anterodorsally, 2.3 times as long as wide and as long as merus. Merus slightly narrower than carpus. Ischium about 0.5 length of merus and about 2 times as long as basis.

Second pereiopod (Fig. 4C ) slender and longer than first pereiopod. Chela 2.2 times as long as wide, 0.72 times length of carpus. Movable finger 3.5 times as long as wide and 1.5 times as long as palm, setal brushes well developed. Carpus 5.2 times as long as wide, distal part normal, about 0.7 times length of merus.

Third pereiopod (Fig. 4D ) slender. Dactylus 2.8 times as long as wide (Fig. 5A ) (female 2.4, Fig. 5B ), ending in prominent claw-like spine surrounded by simple setae and 4-6 spines. Propodus 5.5 times as long as dactylus, bearing about 20 thin spinules evenly and loosely distributed on ventral margin, 13.5 times as long as wide. Carpus 0.71 times length of propodus. Merus 1.8 times length of carpus, with about 3-4 strong spines on the posterior margin. Ischium with a spine on the posterior margin.

Fifth pereiopod (Fig. 4E ) dactylus 3.6 times as long as wide, ending in prominent claw-like spine surrounded by simple setae, inner margin with about 30 and comb-like spines. Propodus 5.7 times length of dactylus, bearing about 15 spinules in two rows on ventral margin, 19.4 times as long as wide. Carpus 0.51 times length of propodus. Merus 1.5 times length of carpus, with about 3 strong spines on the posterior margin. Ischium about 0.3 times length of merus and 2.1 times length of basis.

First pleopod (Fig. 4F ) endopod tongue-like, about 2.0 times as long as wide, 0.4 times length of exopod, both inner and outer margin with spine setae, appendix interna well developed, arising from distal 1/5 of endopod, overreaching end of endopod, with cincinuli distally. Exopod 5.3 times as long as wide.

Second pleopod endopod slender. Appendix masculina (Fig. 4G ) strong, about 3/5 length of endopod, bearing about 25 long, spine-like setae distally as well as on distal part of inner margin. Appendix interna of endopod reaching 1/2 of appendix masculina, with cincinuli distally (Fig. 4G ).

Telson (Fig. 4H ) about 0.5 times the postorbital carapace length and as long as sixth abdominal somite, tapering posteriorly and ending in a small median projection, dorsal surface with about 6-7 pairs of submarginal spines. Posterior margin with a pair of outermost spines and 5 pairs of intermediate spines that are slightly shorter than the lateral pair. Exopod of uropod longer and wider than endopod, both with plumose marginal setae. Diaeresis bearing 8-11 (holotype 11) spines.

Eggs 0.85-0.91 × 1.20-1.27 in diameter.

Color strongly degenerated, translucent to flavescent (Fig. 1 ).

Etymology.

The specific name is in honor of Ashima, who is a famous female character of the local legend spreading among the Yi nationality and is a symbol of love and bravery.

Distribution.

Yunnan Province (Xiangshuiqing Cave), China.

Habitat.

Subterranean river in a karst cave.

Figures

Figure 1. Live specimens of Sinodina ashima sp. nov.

Figure 2. Cephalothorax of Sinodina ashima sp. nov., lateral view, showing the variation of the rostrum A female paratype, tl 23.5 mm B holotype C male paratype, tl 27.5 mm D female paratype, tl 40 mm. Scale bars: 2.5 mm.

Figure 3. Holotype of Sinodina ashima sp. nov. A cephalothorax and cephalic appendages, lateral view B mandible C antennule D antenna E maxillula F maxilla G first maxilliped H second maxilliped. Scale bars: 2.5 mm (A); 0.25 mm (B, E); 0.75 mm (C, D); 0.5 mm (F-H).

Figure 4. Holotype of Sinodina ashima sp. nov. A third maxilliped B first pereiopod C second pereiopod D third pereiopod E fifth pereiopod F first pleopod G appendix masculina and appendix interna of second pleopod H telson. Scale bars: 0.75 mm (A, C, F); 0.5 mm (B, H); 1 mm (D, E); 0.25 mm (G).

Figure 5. Dactylus of third pereiopod A holotype B female paratype. Scale bars: 0.25 mm.