Caridina serrata Stimposon,1860

Chen, Qing-Hua, Chen, Wen-Jian & Guo, Zhao-Liang, 2018, Caridean prawn (Crustacea, Decapoda) from Dong'ao Island, Guangdong, China, Zootaxa 4399 (3), pp. 315-328 : 316-318

Caridina serrata Stimposon,1860

(Figs. 2,3)

Caridina serrata Stimposon, 1860: 29 [type locality: Hong Kong, southwest China]. Caridina serrata Ortmann, 1894: 406 ; Bouvier, 1905: 76;1925: 258, fig. 593; Kemp, 1918: 289, fig. 12; Cai & Ng, 1999: 1605, figs. 2, 3; Liang, 2004: 173, fig. 83.

Material examined. 17 females (CL: 3.3–6.7 mm), 3 ovigerous females (CL: 3.9–5.7 mm), 17 males (CL: 2.8–5.3 mm), a small spring near the medical clinic of Dong’ao Village (E 113°42'26", N 22°01'12", al. 8.4 m, stn.1), 23 August 2014, coll. Z. L. Guo ; 10 females (CL: 3.4–6.6 mm), 2 ovigerous (CL: 3.7–5.7 mm), 7 males (CL: 2.9–5.6 mm), same site, 26 June 2017, coll. Z. L. Guo, W. J. Chen. 12 females (CL: 3.5–6.8 mm), 2 ovigerous (CL: 3.5–5.8 mm), 8 males (CL: 3.2–5.9 mm), a small springs near Paifang of Dong’ao Village (E 113°42'21", N 22°01'02", al.

29.4 m, stn. 2), coll. 23 August 2014. Z. L. Guo, 5 females (CL: 3.1–6.9 mm), 3 males (CL: 3.1–4.9 mm), same site, 26 June 2017, coll. Z.L.Guo, W. J. Chen. 10 females (CL: 3.1–6.9 mm), 17 males (CL: 2.9–5.9 mm), a small springs near Qiuziquan (E 113°42'18", N 22°01'23", al. 121.9 m, stn. 3), 26 June 2017, coll. Z. L. Guo, W. J. Chen. 6 females (CL: 3.2–5.9 mm), 3 males (CL: 2.5–4.8 mm), a small springs near Dieshi (E 113°42'41", N 22°00'46", al. 51.6 m, stn.5), 26 June 2017,coll. Z. L. Guo, W. J. Chen. 7 females (CL: 3.4–5.5 mm), 1 ovigerous (CL: 3.5 mm), 3 males (CL: 2.5–4.3 mm), a small springs near Dieshi (E 113°43'01", N 22°00'58", al. 34.4 m, stn. 6), 26 June 2017, coll. Leg. Z. L. Guo, W. J. Chen. 11 females (CL: 3.6–7.1 mm), 2 males (CL: 3.5–4.5 mm), a small springs near Dieshi (E 113°43'09", N 22°01'08", al. 22.4 m, stn.7), 26 June 2017, coll. Z. L. Guo, W. J. Chen. 6 females (CL:3.0– 5.6 mm), 3 males (CL: 3.7–4.8 mm), a small springs near Dieshi (E 113°43'09", N 22°01'12", al. 31.8 m, stn. 8), 26 June 2017, coll. Z. L. Guo, W. J. Chen. 8 females (CL: 3.3–6.2 mm), a small springs near Tongchen (E 113°42'54", N 22°01'39", al. 10 m, stn. 9), 26 June 2017, coll. Z. L. Guo, W. J. Chen.

Diagnosis. Rostrum short, straight or slightly curved downwards, reaching the end of eye to the end of second segment of antennular peduncle. The rostral formular: 0-5+6-12/0-3. The stylocerite long, reaching the middle of second segment of antennular peduncle. Endopod of the first male pleopod is rectangular, slightly wider proximally, distal margin broadly rounded, inner margin slightly concave, outer margin slightly convex; appendix interna well developed, arising from distal 1/4 of endopod, reaching beyond tip of endopod ( Fig.2.d ). Appendix masculina rod-shaped, inner margin and distally bearing numerous stout spines; appendix interna reaching about half length of appendix masculina ( Fig. 2. e ). Eggs 0.5-0.7 x 0.9-1.0 mm in diameter.

Remarks. Cai & Ng (1999) provided a thorough redescription and figures of this species based on specimens from Hong Kong and a neotype was designated for C. serrata . They stated that C. serrata only occours on Hong Kong. However, Liang (2004) reported that this species also occurs in Chaqiao, Zhongshan City, Guangdong Province.

An examination the specimens of eight sites from Dong’ao Island showed that agree well description of C. serrata ( Cai & Ng,1999; Liang, 2004), particularly the long stylocerite, the shape of the male first endopod and the appendix masculina of the male second pleopod. There is considerable variation in rostral features, most of specimens are typical rostrum as the description ( Cai & Ng,1999; Liang, 2004), that the rostrum reaches the end of the first segment of the antennular peduncle, some specimens are have the short rostrum that only reaches the end of the eye, also some specimens have the long rostrum that reaches the end of the second segment of the antennular peduncle ( Fig.2. a, b, c ).

Habitat. Caridina serrata is commonly found in pools of very small streamlets, the water is clear and flowing. It have well adaptad and high fecundity, so it is widely distributed everywhere of the island.

Colouration. The live shrimp show green-brown colouration and translucent; the blue spots are dispersed on the carapace; the abdomen is light, there is a blue band on the tergum of the third abdominal segment, extending to pleuron, and an irregular blue band on the fourth and the fifth abdominal segments; the tail is orange colour ( Fig.3 ).

Distribution. Southern China ( Hong Kong, Zhuhai City and Zhongshan City of Guangdong Provinces).

Figures

FIGURE 3. Caridina serrata, live specimen, showing the characteristic colouration, male, stn.3.

FIGURE2. Caridinaserrata, cephalothorax, a.male cl 18.04mm, stn.1;b.male cl 18.98 mm, stn.3; c. male cl 23.27 mm,stn. 5; d. male first pleopod, stn.2; e. appendix masculina and endopod of male second pleopod, stn.2.