Betadevario ramachandrani, Fang, Fang, Devi, Rema, Liao, Te-Yu, Beevi, Jameela & Kullander, Sven O., 2010

Fang, Fang, Devi, Rema, Liao, Te-Yu, Beevi, Jameela & Kullander, Sven O., 2010, Betadevario ramachandrani, a new danionine genus and species from the Western Ghats of India (Teleostei: Cyprinidae: Danioninae), Zootaxa 2519, pp. 31-47 : 35-39

Betadevario ramachandrani , new species

(Fig. 1)

Holotype. ZSI/SRS F.8147. Adult male, 45.1 mm SL. India: Karnataka: Dakshina Kannada: Shimoga District: Agumbe, small stream tributary to Sita River, 2 km upstream from Onake Abbi Fall (13°30’79’’N 75°4’49’’E), 558 mASL; P.K. Pramod, Jan 2008.

Paratypes. NRM 57779, 3, 43.2–48.7 mm SL; NRM 44980, 1, 48.3 mm SL, cleared and stained; NRM 57780, 1, 45.0 mm TL, tissue; NRM 57781, 1, 60 mm TL, tissue; India: Karnataka: Dakshina Kannada: Sita River close to Barkana Falls, bordering Shimoga and Someshwara regions, between Hebri and Somaishwara. (Approximately 13°30’N, 75°00’N). No date, A. Manjunath. Kept in aquarium, preserved 2008. — NRM 60838. 9, 35.1–36.6 mm SL. Same data as holotype. — ZSI/SRS F.8147. 10, 49.0–61.0 mm SL; Same locality as holotype; P.K. Pramod, 16 Dec 2007.

Diagnosis. As for the genus. For field identification purposes B. ramachandrani is readily distinguished from all species of Devario (see Fig. 1) by its colour pattern including a wide light horizontal band along the middle of the side bordering a wide dark lateral band along the abdominal side, and the long rostral and maxillary barbels.

Description. Measurements and counts were taken from the holotype and nine paratypes, ZSI/SRS F.8147, and NRM 60838 ( Table 3 ). Counts were taken also from NRM 57779 and NRM 44980. General body features and pigmentation are illustrated in Figs. 1–2.

FIGURE. 1. Betadevario ramachandrani . Holotype, ZSI/SRS F.8147, male, 45.1 mm SL, from Sita River, Karnataka, India.

Body laterally compressed, elongate. Predorsal contour slightly curved, with minor occipital indentation, slightly ascending, sloping posteriorly from dorsal-fin insertion. Prepelvic contour slightly curved. Chest conspicuously more compressed below pectoral-fin base, not keeled. Snout short, rounded in dorsal aspect, obtuse in lateral aspect, about as long as eye diameter. Infraorbital process very low, long, with slightly curved margin. Danionine notch caudally margined by well developed anteromediad projecting laminar dentary process, processes of opposite sides meeting medially when mouth closed. Skin cover absent from distal part of infraorbital process, dentary process, and narrowly anterior margin of supraorbital. Mouth terminal, obliquely directed upwards. Small skin-covered bony knob at dentary symphysis fitting into depression in upper jaw. Maxilla reaching to below anterior margin of orbit. Jaws equal anteriorly; lower jaw ending anteriorly at horizontal through about middle or upper ¼ of eye. Small tubercles with broad base and sharp pointed tip arranged in 2–3 rows along adlabial lateral margin of dentary. Minute tubercles present in groups along anterior pectoral fin rays in six of 10 specimens. Rostral barbel extending beyond to posterior margin of vertical limb of preopercle. Maxillary barbel longer than rostral barbels, reaching to slightly beyond vertical from posterior margin of opercle. Sexual dimorphism expressed only in presence of tubercles on pectoral-fin rays, and slightly more developed tubercles on dentary in males.

Lateral line complete, along 32 (3), 33(8), 34 (2) scales, and 1–2 scales on caudal-fin base; comprising six tubed scales running caudoventrad followed by tubed scales paralleling ventral outline and ending on lower half of caudal peduncle. Median predorsal scales 16 (10), 17 (3). Lateral scale rows passing between dorsal and pelvic fins ½6+1+1. Circumpeduncular scale rows 7 above, 3 below lateral lines (total 12) in five specimens; 9 above, 3 below (total 14) in eight specimens. A row of scales along anal-fin base. Slightly less than ¼ of caudal-fin length scaled basally.

Dorsal-fin rays ii.7 ½ (4), ii.8 ½(10). Anal-fin rays iii.11 ½ (7), iii.12 ½(7). Pectoral-fin rays i.12 (2), i.13 (1). Pelvic-fin rays i.6 (2), i.7 (10). Dorsal fin inserted at highest point of dorsum, little posterior to middle of body. Anal fin inserted below anterior rays of dorsal fin. Pectoral-fin insertion at about vertical through posterior margin of osseous opercle; pectoral fin reaching slightly past origin of pelvic fin. Pectoral-fin axial lobe well developed. Pelvic fin inserted slightly anterior to midbody, not reaching anal-fin origin. Pelvic axillary scale present. Caudal fin forked; procurrent rays 6 in both lobes, except in one specimen with 7 ventrally; principal rays 10+9 (14).

Vertebrae 16+19=35 (4), 16+20=36 (2), 17+18=35 (5), 17+19=36 (3). Predorsal vertebrae 14 (14). Vertebral centra contained within caudal peduncle 8(6), 9 (8). Pharyngeal teeth 5,3,2/2,3,5 (one specimen dissected, Fig. 3 ).

Coloration in preservative. No sexual dichromatism. Dark brown stripe marking dorsal midline from occiput to dorsal-fin base. Dorsal side and dorsal margin of caudal peduncle brown, except slightly lighter zone on each side of mid-dorsal brown stripe. Contrasting yellowish-white horizontal band, about 1½ scales deep from orbit to dorsal half of caudal-fin base. Dark brown cleithral spot covering three scales posterior to cleithrum, immediately ventral to light horizontal band. Side ventral to light horizontal stripe grayish brown to a depth of about three scale rows. Abdomen, area close to anal fin base, and ventral margin of caudal peduncle, pale yellowish. Top of head brownish. Cheek yellowish, peppered with brown melanophores. Gill cover and jaws grayish to hyaline. Dorsal fin basally light grey; dark grey to blackish stripe across middle of fin, margined distally by wide whitish zone and grey margin. Anal fin pale grayish or hyaline basally; blackish stripe from middle of anterior rays to tips of posterior rays; anterior margin white or hyaline. Pelvic and pectoral fins hyaline, pectoral fin lightly pigmented along first fin-ray. Caudal fin basally grayish, continuing dark body pigmentation, gradually fading along middle rays; pale grayish along dorsal and ventral margins of fin.

Live coloration ( Fig. 4 ). Bluish green dorsally, light horizontal stripe golden yellow, dark lateral band deep blue. Abdomen silvery. Dorsal fin yellow along middle, bluish distally. Anal fin yellow basally, white distal to dark band. Pelvic fins lemon yellow. Caudal fin, except for dark stripes lemon yellow.

Geographical distribution. Known only from the type locality area in the upper Sita River drainage on the southwestern coast of India ( Fig. 5 ). The type locality, at 558 m a.s.l. is a small, high-altitude stream with a cascade and riffle-pool habitat ( Fig. 6 ). The width of the stream was 2–2.7 m, the depth at most about 30 cm. As recorded at 1245h on 16 December 2007, the water temperature was 18.9°C, pH 6.4. The area has a notably high precipitation, Agumbe receiving an average rainfall of 7640 mm annually.

Phylogenetic position. Addition of Betadevario ramachandrani to the morphological matrix of danionines used by Fang (2003), as well as to the molecular dataset used by Fang et al. (2009) places the species with Devario ( Figs. 7–8 ). In the molecular tree ( Fig. 8 ), Betadevario is the sister group of other Devario , including the type species D. devario (Hamilton) , whereas in the morphological tree ( Fig. 7 ) D. devario is more basal.

Etymology. Named for Professor Alappat Ramachandran, School of Industrial Fisheries, Cochin University of Science and Technology, Kochi, in recognition of his contributions fisheries and sea food production management and studies on indigenous ornamental fishes.

Figures

FIGURE 3. Betadevario ramachandrani. Left side pharyngeal bone in anterolateral aspect. NRM 57781, 60 mm TL.

FIGURE 4. Betadevario ramachandrani. Freshly collected specimen from the type locality showing live coloration.

FIGURE 5. Betadevario ramachandrani. Location of type locality.

FIGURE 6. Betadevario ramachandrani. Type locality. Photo P. K. Pramod.

FIGURE 7. Cladogram of relationships among danionin cyprinids, based on morphological characters. Strict consensus tree from two most parsimonious trees, tree length 96 steps, consistency index 0.4688, homoplasy index 0.5313, retention index 0.7488, rescaled consistency index 0.3510. Numbers at nodes are bootstrap values in per cent from 1000 replications to the left of the slash, and the Bremer Decay Index to the right. Bootstrap values less than 50 % are not shown. Squares on branches show character states for each branch, the character number above the square, the state below. Only unambiguous transformations are shown; open squares are homoplasies, solid squares are synapomorphies.

FIGURE 8. Phylogram of relationships among danionin cyprinids. 50 % majority-rule consensus tree obtained from the Bayesian analysis based on nucleotide sequences of mitochrondrial cytochrome b and nuclear rhodopsin genes. Values above and below nodes indicate posterior probability and bootstrap support, respectively. Values lower than 95 (posterior probability) and 50 (bootstrap support) are not shown. Branch lengths are proportional to estimated change indicated on the lower left of the figure.

Tables

TABLE 3. Morphometry of Betadevario ramachandrani, ZSI / SRS F. 8147 (holotype) and NRM 60838 (9 paratypes). Measurements are in per cent of SL, except for SL and TL (in mm). SD = standard deviation.

	N Min	Max	Mean	SD
SL (mm)	10 35.1	53.8	45.1	5.47
Total length	8 46.7	71.0	59.1	8.04
Body depth	10 29.0	30.8	30.0	0.60
Head length	10 24.6	26.5	25.3	0.53
Snout length	10 7.1	7.9	7.4	0.23
Head depth	10 17.6	19.7	18.8	0.66
Head width	10 12.9	14.5	13.7	0.52
Upper jaw length	10 11.0	11.7	11.3	0.28
Lower jaw length	10 12.8	14.3	13.5	0.54
Orbital diameter	10 7.5	8.8	8.1	0.44
Interorbital width	10 10.8	11.7	11.3	0.29
Caudal peduncle length	10 19.1	22.1	21.2	1.03
Caudal peduncle depth	10 12.3	13.4	12.9	0.41
Dorsal-fin base length	10 13.4	15.1	14.1	0.58
Anal-fin base length	10 17.5	18.8	18.1	0.47
Predorsal length	10 58.9	62.4	60.6	1.12
Preanal length	10 60.8	64.7	63.5	1.25
Prepelvic length	10 44.1	49.5	46.7	1.43
Pectoral-fin length	10 22.7	25.3	23.8	0.98
Pelvic-fin length	10 15.0	17.0	16.2	0.58
Rostral barbel length	10 13.0	15.2	14.0	0.70
Maxillary barbel length	10 18.4	22.0	20.1	1.27