Coutierella tonkinensis Sollaud, 1914

Li, Xinzheng, Bruce, Alexander J. & Manning *, Raymond B., 2004, Some Palaemonid Shrimps (Crustacea: Decapoda) From Northern South China Sea, With Descripitions Of Two New Species, Raffles Bulletin of Zoology 52 (2), pp. 513-553 : 514-515

Coutierella tonkinensis Sollaud, 1914

( Fig. 1 )

Coutierella tonkinensis Sollaud, 1914: 318-322 , Figs. IIIB, IV;

Bruce, 1989a: 177-186, Figs. 1-6 ; Holthuis, 1993: 104, Fig. 91. Palaemonetes tonkinensis - Kemp, 1925: 315-316.

Palaemonetes (Palaemonetes) tonkinensis - Holthuis, 1950: 10. Palaemonetes tonkinensis tonkinensis - Liu et al., 1990b: 249, Fig.

40.

Material examined. – 8 males, 3 females ( IOCAS) , 1 male, 1 female ( ZRC) , 1 male, 1 female (SI), Haikou, Hainan Is. , fishery market, 18 Jan.1956 ; 1 male, 2 females (1 ovig), 3 juv.. ( IOCAS), CN 90 C-047A1, Haikou , algae culture field, coll. J. Y. Liu, 4 Nov.1990 ; 1 female, CN 92 C-1065B, Wanquan River, Qionghai, Hainan Is. , coll. X. Li, 2 Apr.1992 .

Diagnosis. – Rostrum well developed, compressed, exceeding antennular peduncle, armed with 5-7/1-3 teeth; carapace with antennal and branchiostegal spines, branchiostegal suture distinct anteriorly; without supraorbital and hepatic spines; orbital notch distinct, anterior lateral margin of carapace concave, anterolateral angle slightly produced. Mandible robust, without palp, molar process stout, with several blunt marginal teeth, incisor process robust, with 4 teeth. First maxilliped with subcylindrical palp, separated by deep Ushaped notch from large, broad basal endite. First pereiopods slender, extending to distal margin of scaphocerite, chela small. Second pereiopods slender, subequal, similar, extending beyond scaphocerite by fingers. Endopod of first pleopod in male without appendix interna. Fourth thoracic sternite with slender medium process. Dactyls of ambulatory pereiopods simple. Telson with 2 pairs of small dorsolateral spines, arising at 0.5, 0.67 of telson length respectively, posterior margin with 6 pairs of spines, lateral pair short, similar to dorsolateral spines, lateral second pair large, about 3 times as long as the lateral pair, submedian pairs more slender and shorter.

Distribution. – Red River, Vietnam and Hong Kong, fresh to brackish and salt water.

Remarks. – Sollaud (1914) established the genus Coutierella , but Kemp (1925) treated it as a junior synonym of the genus Palaemonetes and all authors since then followed Kemp until Bruce (1989a), who re-established it as a full genus based on its characteristic mouthparts and the apex of the telson. Only one species, C. tonkinensi s was described in this genus, which is found only in the northern part of the South China Sea and adjacent freshwater habitats. It was previously recorded in Chinese waters from Hong Kong ( Bruce, 1989a).

Liu et al. (1990b) described a subspecies from fresh water or estuaries of Fujian Province to the estuary of Zhujiang River (Pearl River), Guangdong Province, named Palaemonetes tonkinensis guangdongensis (= Coutierella tonkinensis guangdongensis ). The main differences between C. t. guangdongensis and the nominal subspecies C. t. tonkinensis they described are: the former has a rostrum with 5-7 dorsal teeth (average 6.06 teeth based on their material), and telson with 3-4 pairs of posterior spines (average 4.0 pairs based on their material); the latter with rostrum with 7-9 dorsal marginal teeth and telson with 6-7 pairs of posterior spines. Bruce (1989a) reported on material from Hong Kong, at the estuary of the Zhujiang River, stating that the rostrum of the species has 5-7 dorsal teeth, and telson with posterior spinulation rather irregular and presenting the appearance of abnormal variations. According to his illustrations of the posterior telson margin, the spines and spinules in total vary from 4 to 7 pairs. In our material from Hainan Island, 12 of which have the rostrum with 6 dorsal teeth, 7 with 7 teeth, 1 with 8 teeth, 1 juvenile with 5 teeth, the average is 6.5. Concerning the posterior spines of the telson, among the Haikou specimens collected in 1956, the males have 5-8 pairs, average 5.8, females have 6-8 pairs, average 6.7, the females usually have more spines than males; the female of 90C-1065B from Wanquan River (NE of Hainan Island) has 5 pairs of posterior telson spines; the telsons of male and females of 90C-047A from Haikou are damaged, one of a juvenile with 13 spines and spinules, another with 10. So, the average number of pairs of posterior telson spines is 6.2. According to Liu et al. (1990b), it is difficult to decide which subspecies our material, as the number of dorsal rostral teeth is similar to C. t. guangdongensis and that of posterior telson spines is similar to the typical subspecies. Bruce’s (1989a) specimens are similar to C. t. guangdongensis in the number of dorsal rostral teeth but the number of posterior telson spines is more than in this subspecies. No specimen in our material from Hainan Island has plumose setae on the posterior telson margin, in Bruce’s (1989a) specimens from Hong Kong and Sollaud’s (1914) material, there are several plumose setae, and in Liu et al.’s (1990b) material of Palaemonetes tonkinensis guangdongensis from Guangdong Province, there are many these setae. There may be a series variation in the numbers of rostral teeth, posterior marginal spines or spinules and plumose setae of telson, in the species, from Viet Nam and Hainan Island, to Guangxi, Guangdong and Fujian. As such, the two subspecies may represent two extreme forms of variation in the same species, and it is possible that Palaemonetes tonkinensis guangdongensis might well be proven to be a junior synonym of Coutierella tonkinensis . However, until further samples and more intermediate forms between the two subspecies are collected to clearly show the extent of this variation, we prefer to deal with the two forms as two subspecies.

Figures

Fig. 1. Coutierella tonkinensis Sollaud, 1914. a, carapace and rostrum, lateral view; b, mandible; c, 1st maxilliped; d, telson; e, tip of telson.

Fig. 2. Exopalaemon orientis Holthuis, 1950. a, carapace and rostrum, lateral view; b, mandible; c, 1st pereiopod; d, 2nd pereiopod; e, 3rd pereiopod; f, same, dactyl and propodus; g, 5th pereiopod; h, same, dactyl and propodus.

Fig. 3. Leander tenuicornis (Say, 1818). a, carapace and rostrum, lateral view, female; b, same, male; c, antennule.

Fig. 4. Leandrites stenopus Holthuis, 1950. a, carapace and rostrum, lateral view; b, eye; c, antennule; d, scaphocerite; e, telson and uropod, dorsal view; f, tip of telson; g, eggs.

Fig. 5. Leandrites stenopus Holthuis, 1950. a, b, carapace and rostrum, lateral view; c-e, mandible, c, d, right, e, left; f, maxillula; g, maxilla; h, 1st maxilliped; i, 2nd maxilliped; j, 3rd maxilliped.