Coutierella tonkinensis Sollaud, 1914: 318-322 Palaemonetes tonkinensis Coutierella tonkinensis Sollaud, 1914 Palaemonetes (Palaemonetes) tonkinensis Holthuis, 1950: 10 Palaemonetes tonkinensis tonkinensis Liu et al., 1990b: 249 Some Palaemonid Shrimps (Crustacea: Decapoda) From Northern South China Sea, With Descripitions Of Two New Species Li, Xinzheng Bruce, Alexander J. Manning *, Raymond B. Raffles Bulletin of Zoology 2004 52 2 513 553 9GP3J Sollaud, 1914 Sollaud 1914 [922,1343,1056,1081] Malacostraca Palaemonidae Coutierella GBIF Animalia Decapoda 1 514 Arthropoda species tonkinensis  ( 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.  Fig. 1.  Coutierella tonkinensis Sollaud, 1914. a, carapace and rostrum, lateral view; b, mandible; c, 1st maxilliped; d, telson; e, tip of telson.    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 90C-047A1, Haikou, algae culture field, coll. J. Y. Liu,  4 Nov.1990;  1 female, CN 92C-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, Vietnamand 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  Palaemonetesand 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. tonkinensis was described in this genus, which is found only in the northern part of the South ChinaSea 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. guangdongensisand the nominal subspecies C. t. tonkinensisthey 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 juvenilewith 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. guangdongensisand that of posterior telson spines is similar to the typical subspecies. Bruce’s (1989a)specimens are similar to C. t. guangdongensisin 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 Kongand Sollaud’s (1914)material, there are several plumose setae, and in Liu et al.’s (1990b) material of  Palaemonetes tonkinensis guangdongensisfrom 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 Namand 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 guangdongensismight 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. [347,613,308,329] IOCAS 2 515 11 3 8 ZRC 2 515 2 1 1 1956-01-18 Is. Haikou 2 515 2 1 1 Hainan 1990-11-04 IOCAS J. Y. Liu Haikou 2 515 CN 90 3 2 1 Hainan 1992-04-02 CN X. Li Wanquan River Is. Qionghai 2 515 CN 92 1 1 Hainan