Botia kubotai, Maurice Kottelat, 2004

Maurice Kottelat, 2004, Botia kubotai, a new species of loach (Teleostei: Cobitidae) from the Ataran River basin (Myanmar), with comments on botiine nomenclature and diagnosis of a new genus., Zootaxa 401, pp. 1-18 : 2-8

Botia kubotai , new species

(Fig. 1)

Holotype. MHNG 2644.24, 84.9 mm SL; Myanmar: Kayin [Karen] State: stream "Chon Son" between Kyondaw and Phadaw, about 20 km northwest of Payathouzu (at border with Thailand); about 15°25'N 98°15'E; don. K. Kubota, December 2002.

Paratypes. CMK 17774, 10; 36.5-83.5 mm SL; same data as holotype . - CMK 17943, 215, MHNG 2644.25, 10; NRM 49891, 10; ZRC 49125, 10; 42.7-106.5 mm SL; same locality as holotype; don. K. Kubota, March 2003 . - CMK 17829, 3, 35.0-68.6 mm SL; aquarium material, probably from same locality as holotype; don. T. Halvorsen, 18 Mar 2003 . - ZRC 47858, 3, 37.2-48.4 mm SL; Thailand: aquarium trade, 19 May 2003 .

Diagnosis. Botia kubotai is distinguished from all other species of the genus by its unique body colour pattern with three black stripes and five black bars leaving four pairs of elongate yellow blotches; with increasing age, the bars and stripe widen, the yellow blotches become more slender and rows of small yellow spots are added in the stripes and in the bars.

Description. General appearance is shown in Figure 1; morphometric data are in Table 1. Body compressed. Ventral profile straight from lower jaw to caudal-fin base. Dorsal profile regularly arched to dorsal-fin origin, then slightly descending along dorsal-fin base, then horizontal to caudal-fin base. Suborbital spine bifid, outer prong straight, very short; inner prong slightly curved. Two pairs of rostral barbels, one pair of mandibular barbels(at posterior corner of mouth) and one pair of mental barbels. Lips finely pleated.

Dorsal fin with 4 simple and 9 (holotype) or 10 (10 paratypes) branched rays, last two rays sharing same pterygiophore (8-9½); distal margin straight to slightly concave. Caudal fin deeply forked, with 9+8 branched rays. Anal fin with 3 simple and 6 branched rays, last two sharing same pterygiophore (5½). Pelvic fin with 8 rays, reaching beyond anus but not to anal-fin origin. Pectoral fin with 13(8) or 14(3) rays, almost reaching pelvic-fin origin.

Coloration. Based on examined material, live aquarium specimens, and photographs. Colour pattern of body and head complex, with conspicuous changes with growth, making it difficult to describe with accuracy. Pattern variable and therefore following description somewhat schematized. Smallest individuals with relatively paler appearance than larger ones, resulting mainly from dark markings being less contrasted and narrower. An ontogenic trend in decreasing pale areas and increasing dark ones, and evolving from a yellow body with a pattern of intersecting stripes and bars towards a black body with rows of yellow spots (through a widening of the bars and stripes and a reduction of blotches coupled with addition of median rows of spots in bars and stripes). Stripes and bars usually distinct entities in smallest individuals, fused and more or less merged in large ones.

In smallest available specimens (less than about 40 mm SL; Fig. la), basic body pattern made of three stripes and five bars. A midlateral stripe running along lateral line, a ventral stripe from above pectoral base to lower contour of caudal peduncle, and a dorsal stripe from upper margin of eye to posterior extremity of dorsal base, parallel to but not touching dorsal mid-line. Anterior bar immediately behind gill opening, second bar midway between gill opening to dorsal-fin origin, third bar under dorsal-fin base, fourth bar at anal-fin origin, fifth bar on posterior third of caudal peduncle and base of caudal fin. Bars continuous across belly and back. Bars darker and more contrasted than stripes. Each bar with a median vertical row of one to five small, roundish yellow spots. Intersections of stripes and bars leaving four pairs of longitudinally elongated yellow blotches, and two narrow yellow saddles in predorsal area. Head with narrow bar through eye, a band from eye to posterior part of upper lip, and one from top of head to tip of snout.

In specimens about 40-50 mm SL (Fig. 1b -c), colour pattern modified as follows: stripes become darker, as contrasted as and merged with bars. Bars and stripes widened relative to paired yellow blotches. An additional row of small roundish spots in midlateral stripe, and a few spots in dorsal and ventral stripes.

In specimens about 55-70 mm SL (Fig. 1d): additional rows of spots in bars 2-4, in band from eye to upper lip, and in band on top of head, eye bar branched below eye. In specimens about 80-85 mm SL (Fig. 1e), additional row of spots in all bands, resulting in a general appearance of a black body with more or less regular horizontal rows of yellow spots. Large blotches much reduced, remaining as four pairs of horizontally elongated spots.

Dorsal fin with a broad basal band (usually with a notch or a spot continuing row of yellow spots of third body bar) and a subdistal row of elongated blotches on rays. Caudal fin with three (small specimens) or four (specimens larger than 80 mm SL) vertical bands on each lobe, anterior one continuous across whole fin. Anal fin with two (small specimens) or three (specimens larger than 60 mm SL) bands. Pectoral fin with three and pelvic fin with two bands on dorsal surface, usually regular but occasionally branched or anastomosed.

Etymology. Named for Katsuma Kubota, in appreciation for his help with various projects and for the gift of valuable material, including the first known specimens of this species with locality information.

Distribution. Botia kubotai is definitively known from headwaters of the Ataran basin in Myanmar (Fig. 2). A stream "Chon Son" does not appear on the maps available to me, but the stated locality clearly is in the Megathat Chaung, a headwater of the Ataran (see below). It possibly also occurs in the headwaters of the same basin in Thailand.

Discussion

Comparison. Botiine loaches have traditionally been placed in the genera Leptobotia and Botia , the last one divided in 3 subgenera ( Botia , Hymenphysa , Sinibotia ; see Fang, 1936; Nalbant, 1963; Taki, 1972). The presence of a pair of mental barbels and the type of colour pattern of B. kubotai makes it a member of the subgenus Botia (Botia) auct. (hereunder called Botia sensu stricto ), whose members are known from the Salween basin westwards to the Indus basin. The species of Botia s.s. have been revised by Menon (1993). Menon recognised two 'complexes' (but neither defined, diagnosed nor discussed them) within Botia s.s. , with the following species and synonyms: a) the almorhae complex , with B. almorhae (synonyms: B.grandis , B. rostrata , B. lohachata , B. dayi ), B. birdi , B. dario (synonyms: Cobitis geto , Diacantha flavicauda , D. zebra ), B. histrionica ; b) the striata complex , with B. striata .

Further, Menon merely mentions B. macrolineata in an addendum (p. 113) and B. javedi has been described since from Pakistan.

As for most Indian fish taxa presently recognised in the literature, it is doubtful whether Menon's species limits and synonymies will survive a critical revision based on fresh and well preserved material of various growth stages. Menon simply placed names in synonymy. He did not justify, discuss or explain any of his actions. It is not the place here to venture into a discussion of species-level systematics of Indian botiines; nevertheless, the geographic position of B. kubotai at the extreme southeastern edge of the range of Botia s.s. and the existing material and information on botiine species recorded from the adjacent Salween and Irrawaddy drainages allows one to recognise this species as new and to suggest that it has no immediate relationships with any Indian species.

Menon recorded a single species of Botia s.s. from Myanmar, B. histrionica (see also Rendahl, 1948). Blyth's description of B. histrionica is not very informative, but he described the colour pattern of the species here identified as B. histrionica : "The bands of the body are broad and subregular in shape, each containing a pale round spot at the lateral line and another on the ridge of the back". Day (1878) described and figured a single specimen, referring to Blyth's description and his 1870 paper in which he (Day) explicitly mentioned having examined a single specimen received from "Major Berdmore at Pegu". This most likely is the holotype or a syntype of B. histrionica . The drawing agrees with Blyth's description and the above diagnostic features.

Botia kubotai is immediately distinguished from B. histrionica by its colour pattern (compare Figures 1 and 3). Botia histrionica has a yellowish brown body with 5 bars in positions identical to those of small B. kubotai . The smallest individuals also have a few round pale spots in the bars and a vague indication of a midlateral stripe (vs. 3 stripes in B. kubotai ). But in larger individuals, the stripe disappears and the bars become very irregular or dissociated into blotches, resulting in a mainly pale coloured body with irregular dark markings, while in B. kubotai colour pattern evolves from a relatively pale one towards a mostly black body with an 'organised' pattern of yellow spots and blotches. The black pattern on the fins of B. histronica is also less extensive: the black band at dorsal-fin base is very narrow or absent (vs. broad), there is usually only one band on the pelvic (vs. two).

Botia histrionica was originally described from "Tenasserim" (Blyth, 1860: 166) but the type locality is listed as "Pegu" by Menon (1993: 43) and Menon & Yazdani (1968: 120). Similar discrepancies between Blyth's published data and those appearing on later ZSI labels are discussed by Ng & Kottelat (2001) who concluded that there is no evidence to conclude that the label data are correct (they might be correct, but without supporting evidence it would be premature to accept them as correct). The "Pegu" localities possibly date back to Day (1870), but it seems clear from his various statements "received from Berdmore at Pegu", "received from Major Berdmore, Pegu", "Pegu (Major Berdmore)" that Pegu could have been the place of residence of Berdmore and not the place where he collected the fishes. For some species, Day unambiguously stated "collected at Pegu", but we have no way to know whether this was a guess or based on actual data.

Kottelat & Chu (1987) reported botiines from the Chinese stretches of the Irrawaddy (Fig. 3d) and Salween which they tentatively identified as B. rostrata . The specimens are no longer accessible for direct comparison, but they seem to be large B. histrionica with the bars dissociated one step further. Botia rostrata is considered as a synonym of B. almorhae by Menon (1993), a species reported from the Himalayan foothills, from Darjeeling to Rajasthan.

Using Menon's (1993) key, B. kubotai keys out as B. almorhae . Menon describes B. almorhae as having a sexually dimorphic colour pattern; but he does not provide evidence to demonstrate that these colour patterns effectively correspond to different sexes. These colour patterns were apparently recognised as different species by earlier authors, but this also is not discussed by Menon. In the absence of material, I tentatively follow Menon's conclusions.

The colour pattern of adult males B. almorhae is reminiscent of that of large B. kubotai with its pale spots surrounded by a blackish background (the rendering of the published illustrations does not allow to recognize if there is an organised pattern in the distribution of the spots). There are more bands on the caudal fin (7, vs. 3-4 in B. kubotai ), on the pectoral fin (5, vs. 2-3) and on the dorsal fin (3, vs. 2). The pattern of the females and juveniles B. almorhae is conspicuously distinct. It is missing the three stripes of B. kubotai and the second, third and fourth bars are Y-shaped, leaving a pale triangular saddle along dorsal mid-line; between each pair of bars, on the lateral line, there is a vertically elongated blotch. Problems of identification of B. almorhae and B. birdi are discussed by Kullander et al. (1999).