Koima remadevii ( Shaji, 2002 )

Anoop, V. K., Dahanukar, Neelesh & Raghavan, Rajeev, 2024, Koima, a new genus of nemacheilid loach from the Western Ghats, India (Cypriniformes: Nemacheilidae), Zootaxa 5538 (2), pp. 101-126 : 108-112

Koima remadevii ( Shaji, 2002)

Figs. 6–8

Mesonoemacheilus remadevii Shaji, 2002: 217 , figs. 2–4 (type locality: Kunthi River at Poochipara, Silent Valley National Park , Kerala, India) Holotype: KFRI F900 . Paratypes: CLTV F11541 (2), KFRI F901 (3) (types presumed lost) .

Material examined: KUFOS-AN-2019.1.1–10 , 28.6–66.6 mm SL, 10 ex.; India: Kunthi River at Poochipara, Silent Valley National Park (11.114° N & 76.430° E, 935m ASL); V.K. Anoop, 17 April 2029 .

Diagnosis. Koima remadevii is distinguished from its only known congener, Koima monilis by the lateral line having 3–11 spots (vs. well-developed, moniliform black band along lateral line extending from snout to middle of caudal fin with 17–22 spots), presence of irregular bands or spots on dorsal side (vs. dorsal without bands), small, black spots on dorsal side of head (vs. absence); and thick and wide suborbital flap (vs narrow). Koima remadevii differs from its congener K. monilis with a raw genetic distance of 5.2–6.0% in barcoding region of cox1 gene.

Description. Morphometric data in Table 1 . Body slightly compressed anteriorly, more compressed posteriorly. Head slightly sharp and pointed, head length about 1/4 th of SL. Pectoral fin reaching about halfway to base of pelvic fin. Pointed axillary pelvic lobe. Pelvic fin originates directly opposite to first dorsal-fin ray, reaching about halfway to anal fin, but not reaching anal opening. Pre-anal length about 3/4 th of SL. Anal fin not reaching caudal-fin base. Distal margin of dorsal fin concave. Dorsal-fin base length about 1/7 th of SL. Body depth greater than body width at dorsal-fin origin. Length of caudal peduncle higher than its depth. Caudal fin forked; its length almost equal to head length. Adipose crest on caudal peduncle, lower reaching end of anal fin.

Dorsal fin composed of three supernumerary rays, one unbranched and eight branched rays. Pectoral fins with one unbranched and 10 branched rays, pelvic fins with one unbranched and six branched rays, and anal fin with two supernumerary, one unbranched and five branched rays. Principal caudal-fin rays nineteen. Four to ten procurrent rays supported on upper caudal fin, and three to five on lower caudal fin.

Body including belly entirely covered with scales. Lateral line reaching beyond anal fin, with 72–94 pores. Cephalic lateral line with 7 supraorbital pores, 4+12 infraorbital, 9 preoperculo-mandibular and 3 supratemporal pores. Total vertebrae 36 (2 ex.), with insertion of dorsal fin after 12 th vertebrae, and anal fin after 22 nd vertebrae.

Anterior nostril on front side of flaplike tube, with slightly pointed tip. Mouth semi-circular, its width about 1/4 th of HL. Interorbital width about 1/3 rd of HL, higher than gape width. Upper lip with narrow deep incision and lower lip with wide interruption. Well-developed barbels, outer rostral barbel reaching posterior end of eye, maxillary barbel reaching almost middle of opercle. Suborbital flap thick and wide, larger than nostril. Maximum head width (at posterior end of head) more than half of HL. Head depth at eye nearly half of head length. Interorbital width about 1/3 rd of HL, greater than mouth width. Intestine with a small loop behind stomach.

Sexual dimorphism. Males can be easily identified by their thick and wide orbital flap ( Fig. 8A ), and a layer of tubercles on pectoral-fin rays.

Coloration. Body colour variable, even within the same population. Yellowish-brown ground colour, with uneven irregular bands or spots on dorsal side. Dorsal bands rarely extending below and reaching lateral line, its width thinner in adults. Lateral line with 3–11 spots, with higher numbers in juveniles compared to adults. In small juveniles, (<3 cm), a black stripe is seen starting from posterior end of head and terminating at caudal peduncle. All fins hyaline. In some juveniles, an elongated patch on caudal fin base, turning into two independent spots, one on middle of caudal-fin base and second on upper procurrent rays, in mature adults.

Habitat. Koima remadevii typically inhabits swift-flowing riparian streams with substrates comprising rocks, boulders, and gravel, with sand and silt patches scattered throughout ( Fig. 9 ). These substrates produce a variety of microhabitats, such as gaps under boulders, and clefts between rocks that provide protection from powerful currents. Stream depth (40 cm to 2 m) and width (7m to 20 m) varies according to seasons. Co-occurring species include Ghatsa pillaii , Bhavania australis , Devario malabaricus, Garra mullya, Balitora jalpalli , Mesonoemacheilus guentheri , and Rasbora dandia .

Distribution. Koima remadevii is currently known only from its type locality, Kunthi River (a tributary of the Bharathapuzha River) at Poochippara, inside the Silent Valley National Park, Kerala, India ( Fig. 10 ).

Figures

FIGURE 6. Koima remadevii (in life) from its type locality at Poochippara, Silent Valley, Kerala, India (KUFOS-AN-2019.1.3; 59.43 mm SL).

FIGURE 7. Koima remadevii from its type locality at Poochippara, Silent Valley, Kerala, India A. lateral, B. dorsal and C. ventral views (KUFOS-AN-2019.1.4; 63.27 mm SL).

FIGURE 8. Koima remadevii from its type locality at Poochippara, Silent Valley, Kerala India, in preservative. (A-H) head lateral, head dorsal, head ventral, dorsal fin, pectoral fin, pelvic fin, caudal fin, and coloration below dorsal fin respectively (KUFOS-AN-2019.1.4; 63.27 mm SL).

FIGURE 9. Habitat of Koima remadevii at its type locality, Poochippara, Silent Valley, Kerala, India.

FIGURE 10. Distribution range of Koima remadevii and K. monilis in the Southern part of the Western Ghats, India