Laomedia astacina De Haan, 1841

Anker, Arthur, Pratama, Idham Sumarto, Firdaus, Muhammad & Rahayu, Dwi Listyo, 2015, On some interesting marine decapod crustaceans (Alpheidae, Laomediidae, Strahlaxiidae) from Lombok, Indonesia, Zootaxa 3911 (3), pp. 301-342 : 330-333

Laomedia astacina De Haan, 1841

( Fig. 23 )

Selected synonymy (for full synonymy see Ngoc-Ho 1997):

Laomedia astacina De Haan 1841: 165 , pl. 35, fig. 8, pl. N; Sakai 1962: 27, pls. 5–7, figs. 1–25; Sakai & Miyake 1964: 86, figs. 1–3; Yaldwyn & Wear 1972: 137, figs. 13–20; Kim 1973: 589, fig. 14; Fukuda 1982: 19, figs. 1–7; Ngoc-Ho 1997: 732, fig. 1.

Not Laomedia astacina— Sankolli 1971: 235, figs. 1, 2 (= Laomedia sp., see below); Johnson 1972: 406 (= L. cf. paucispinosa Ngoc-Ho, 1997).

Material examined. Indonesia. 1 female ( RMNH. CRUS.D.56754), southern Lombok, Lembar, prawn ponds, mud flat, in burrows in banks of brackish stream, suction pump, 0–0.2 m at low tide, leg. D.L. Rahayu et al., 14 May 2014 [LB-St5-10].

Description. See Sakai (1962, with some errors), Yaldwyn & Wear (1972), and Ngoc-Ho (1997).

Habitat. Mud flats and muddy sand flats, usually near estuaries or mangroves; in burrows or under rocks, mangrove wood, debris etc., also in fine mud in mangrove swamps, brackish prawn ponds. Depth range: intertidal to about 5 m.

Distribution. Indo-West Pacific: Japan, Korea, China, Taiwan, Vietnam, Indonesia (first record) ( Ngoc-Ho 1997; present study).

Remarks. Following the most recent assessment of Laomedia in Ngoc-Ho (1997), the single specimen from Lombok is morphologically closest to the type species, L. astacina . Based on the material examined by Ngoc-Ho (1997), L. astacina appeared to range from Japan and Korea south to Vietnam; Johnson’s (1972) specimen of L. astacina from Malaysia was re-identified as L. cf. paucispinosa Ngoc-Ho, 1997. Thus, prior to this study, L. astacina was believed to occur in temperate and subtropical waters of East Asia, being “replaced” by L. paucispinosa in the more tropical parts of South-East Asia ( Ngoc-Ho 1997). However, our first record of L. astacina from central Indonesia suggests that this species extends well into the tropics south of the equator.

The female from Lembar, southern Lombok, shows all the typical features of L. astacina , as illustrated by Ngoc-Ho (1997), although a few differences were noted. For instance, in the female from Lombok, the postocular spines are blunter and less projecting compared to those of males from Taiwan and Vietnam ( Ngoc-Ho 1997: fig. 1A, C). The chelipeds of the Lombok female are extremely hairy, covered by large and very dense tufts of setae ( Fig. 23 ), completely concealing small spines on the dorsal surface of the palm and merus; Ngoc-Ho’s (1997) illustrations show chelipeds mostly denuded of setae. More material from Indonesia and adjacent regions ( Malaysia, Philippines, Papua New Guinea) is necessary to properly assess the status of what is currently seen as a tropical population of L. astacina .

The record of L. astacina from Maharashtra, India, by Sankolli (1971), although listed under the synonymy of L. astacina by Ngoc-Ho (1997), most likely refers to a different species, closely related to L. astacina and L. paucispinosa . Sankolli’s single specimen differs from the Japanese specimens of L. astacina (cf. Sakai 1962; Ngoc-Ho 1997) in the shape of the rostrum, which is narrowing distally, with two or three small, closely spaced teeth on the distolateral margins. Sankolli (1971) noted other differences between the Indian and the Japanese specimens, such as the absence of tubercles or teeth on the chelipeds, and the absence of a lateral notch on the uropod rami and telson. More material of Laomedia from India and other localities in the northern Indian Ocean is needed to clarify the taxonomic identity of the species reported by Sankolli (1971).

Figures

FIGURE 23. Laomedia astacina De Haan, 1841: female (cl 8.9 mm) from Lembar, Lombok, Indonesia (RMNH. CRUS. D. 56754), A—dorsal view; B—lateral view; close-up of frontal region, dorsal view.