Indochinamon kimboiense ( Dang, 1975 )

Naruse, Tohru, Quynh, Nguyen Xuan & Yeo, Darren C. J., 2011, Three new species of Indochinamon Yeo & Ng, 2007 (Crustacea: Brachyura: Potamoidea: Potamidae) from Vietnam, with a redescription of Ranguna (Ranguna) kimboiensis Dang, 1975, Zootaxa 2732, pp. 33-48 : 34-37

Indochinamon kimboiense ( Dang, 1975)

( Figs. 1 , 2 , 3 a–c)

Ranguna (Ranguna) kimboiensis Dang, 1975: 73 , fig. 7; 1980: 430, fig. 245; 1992: 318, figs; Dang & Ho 2001: 79, 80, fig. 13; Anonymous 2007: 375, fig. 224.

Potamon kimboiensis— Yeo & Ng 1999: 639; 2003: 1230; Cumberlidge et al., 2009: appendix 1. Indochinamon kimboiense— Yeo & Ng 2007: 283; Ng et al. 2008: 163.

Material examined. Neotype: male (80.7 by 63.5 mm) ( ZMHU), Kim Boi area, Hoa Binh Province, Vietnam, purchased from villagers, 14 & 15 Apr. 2007.

Others: 1 female (55.5 by 43.0 mm) ( ZMHU), 2 males (71.8 by 56.6, 71.5 by 56.8 mm), 2 females (63.0 by 49.5, 52.8 by 41.1 mm) ( ZRC 2010.0165), same data as neotype; 1 male (58.8 by 45.3 mm), 2 females (69.4 by 53.6, 49.9 by 37.4 mm) ( ZRC 2010.0166), stream in Cuc Phuong National Park, about 6 km from main gate, Ninh Binh Province, northern Vietnam, 20°18'N 105°38'E, coll. D. C. J. Yeo, H. H. Ng & X. Q. Nguyen, 16 Sep. 1997.

Diagnosis. Carapace ( Fig. 1 a) broader than long, CW 1.26–1.33 times (mean 1.29, n = 9) CL, low, dorsal surface ( Fig. 2 a) glabrous; regions well defined. Postorbital cristae gently divergent posterolaterally; regions behind epigastric, postorbital cristae weakly granulose to weakly rugose. External orbital angle relatively broadly triangular, outer margin slightly convex to almost straight; epibranchial tooth low; anterolateral margin convex, distinctly serrated, distinctly cristate; posterolateral margins convergent posteriorly; branchial region rugose to granulose. Epistome ( Fig. 2 a) posterior margin median tooth well developed, triangular. Ischium of third maxilliped broadly rectangular; exopod flagellum not exceeding merus width. Male cheliped carpus with anterior part of inner, outer margins not distinctly inflated, inner part distinctly granulose; chela with upper margin of palm granulose. Male abdominal somite 6 with lateral margins very gently convex to almost straight; male telson ( Fig. 1 b) broadly triangular, with lateral margins slightly concave. G1 ( Figs. 3 a, b) broad, gently sinuous; terminal segment relatively short, about 0.30 times length of subterminal segment, relatively slender, about 3.1 times longer than broad, distally slightly curved outwards, subcylindrical, not tapering distally, with tip broadly rounded, with distinct ventral distal opening, with low, narrow dorsal flap, about 0.37 times length of terminal segment; subterminal segment broad, with distinct subrectangular cleft on subdistal outer margin of dorsal surface.

Distribution. Kim Boi, Hoa Binh Province; Chi Ne, Hoa Binh Province; Cuc Phuong, Ninh Binh Province, northern Vietnam ( Dang 1980; Dang & Ho 2001; present study).

Remarks. The status of Ranguna Bott, 1966 [type species: Potamon (Potamon) rangoonense Rathbun, 1904 ], was clarified by Türkay and Naiyanetr (1987, 1989; see also ICZN 1991; Holthuis 1990; Ng 1990). Consequently, various Ranguna species were transferred to other genera, including R. kimboiense Dang, 1975 , which was tentatively moved to Potamon sensu lato (see Yeo & Ng 1999), and later reassigned to Indochinamon because it possesses the suite of characters diagnostic of the genus (see Introduction; Yeo & Ng 2007).

The G1 of I. kimboiense illustrated by Dang (1975: fig. 7; as Ranguna kimboiense ) does not appear to be that of a detached G1, but rather of an in situ G1, with the G2 still inserted in it. Considering this, the G1s of the present specimens ( Figs. 3 a, b) agree very well with Dang’s figures. The present specimens also match Dang’s (1975: fig. 7) illustrations of the carapace and male abdomen, and they should therefore be referred to the present species. The holotype (male 73 by 54 mm, from Kim Boi, Hoa Binh Province) of this species could not be located and is believed to be lost, like those of Indochinamon mieni (Dang, 1967) . Many type specimens from this period were lost because of constant translocation because of the war (see Yeo & Ng 1998: 637, 638). Following recent checks at the Vietnam National Centre for Natural Science and Technology where Prof Dang Ngoc Thanh’s collections (including types) are deposited, and confirmed by Prof Dang, we are now confident that the type material (including holotype) of I. kimboiense are lost as well. The present male specimen from the type locality (80.7 by 63.5 mm) (ZMHU) is hereby designated as the neotype for the species so as to stabilise its taxonomy.

Indochinamon kimboiense is easily separated from all other Indochinamon species except I. bavi n. sp. and I. phongnha n. sp. by the presence of a low but discernible dorsal flap (versus dorsal flap absent in all other Indochinamon species) on the terminal segment of the G1 ( Figs. 3 a, b). Indochinamon kimboiense is morphologically closer to I. bavi and I. phongnha in the G1 (presence of the low dorsal flap) and carapace characters. There are nevertheless consistent differences between them, which are covered in the Remarks for the latter two species (see later).

Figures

FIGURE 1. Indochinamon kimboiense (Dang, 1975). Neotype (ZMHU, male, CL 63.5 mm, CW 80.7 mm). a, dorsal view; b, ventral view.

FIGURE 2. Indochinamon kimboiense (Dang, 1975). Neotype (ZMHU, male, CL 63.5 mm, CW 80.7 mm). a, frontal view; b, major chela.

FIGURE 3. Male G 1 and G 2 of Indochinamon kimboiense (Dang, 1975) and I. bavi n. sp. a, d, right G 1, ventral view; b, e, right G 1, dorsal view; c, f, left G 2, ventral view. a – c, I. kimboiense, neotype (ZMHU, male, CL 63.5 mm, CW 80.7 mm); d – f, I. bavi, holotype (ZMHU, male, CL 42.9 mm, CW 56.8 mm). Scales = 5 mm.