Pethia longicauda, Katwate, Unmesh, Paingankar, Mandar S., Raghavan, Rajeev & Dahanukar, Neelesh, 2014

Katwate, Unmesh, Paingankar, Mandar S., Raghavan, Rajeev & Dahanukar, Neelesh, 2014, Pethia longicauda, a new species of barb (Teleostei: Cyprinidae) from the northern Western Ghats, India, Zootaxa 3846 (2), pp. 235-248 : 236-242

Pethia longicauda , sp. nov.

( Figure 1 , 2 , 3 )

Holotype. BNHS FWF 96, 36.0 mm SL; India: Maharashtra: Kolhapur District: Hiranyakeshi River near Gavse- Ajara, 16o04'06''N 74o05'30''E, 690 m a.s.l.; U. Katwate, M. Paingankar and N. Dahanukar, 11 June 2013.

Paratypes. BNHS FWF 97–100, 4 ex., 32.0– 37.7 mm SL; same data as holotype; WILD-14-PIS-073–075, 3 ex., 30.1–35.7 mm SL; same data as holotype; ZSI-WRC P/3950–51, 2ex., 31.4–37.6 mm SL; same data as holotype.

Diagnosis. Pethia longicauda is distinguished from all its congeners by a combination of characters that includes a distinct long and shallow caudal peduncle; incomplete lateral line; lateral-line pored scales ceasing after 5th or 6th lateral-line scale; 22-24 scales in lateral series; ½3/1/3½ transverse scale rows; barbels absent; lips well developed with a distinct lateral fold on snout; 13–14 rakers on the first ceratobranchial; dorsal fin origin closer to the snout tip than to base of the caudal peduncle; 5 predorsal neural spines; dark-black humeral spot covering 3rd and 4th lateral-line scales and extending to one scale above the lateral-line row; two black blotches on caudal peduncle with first one distinct, covering 16th–18th scale in lateral series, and second hazy, covering 20th–22nd scales in lateral series.

Description. For general shape and appearance see Figure 1 . Morphometric and meristic data for the holotype and 9 paratypes provided in Table 1 .

Body elongate, shallow; compressed laterally; predorsal contour convex, rising gradually up to dorsal-fin origin, thereafter sloping down towards hypural notch. Ventral profile convex up to base of pelvic fin, running almost straight towards anal-fin origin, sloping down sharply from anal-fin origin towards posterior end of anal-fin base, then almost straight to hypural notch. Caudal peduncle slender, elongate, its length 1.2–1.8 times its depth.

Head small, laterally compressed. Snout rounded, smooth, slightly shorter than or equal to eye diameter, with a distinct lateral fold and fleshy overhanging upper lip. Eyes large, dorso-laterally positioned, closer to snout tip than margin of operculum, diameter 1.3–1.7 interorbital width. Mouth small, subterminal, ventrally ‘U’ shaped, angle of gape not reaching to vertical from anterior margin of eye. Upper lip relatively thicker, more fleshy than lower lip; lower lip not interrupted. Barbels absent.

Dorsal fin originating behind the pelvic-fin origin, closer to tip of snout than to base of caudal peduncle, its distal margin concave, height less than head length. Dorsal fin with 3 unbranched and 8 branched rays, last unbranched ray strong, osseous, densely serrated posteriorly. Pectoral fin with one unbranched and 11 (1), 12 (7) or 13 (2) branched rays, its tip rounded, reaching one or two scales anterior to pelvic-fin origin. Pelvic fin with one unbranched and 7 branched rays, its tip rounded, not reaching vent when adpressed. Anal fin with 3 unbranched and 5 branched rays, its distal margin concave with rounded corners. Caudal fin forked, lobes making more than half of fin length, their tips rounded. Principal branched caudal-fin rays dorsally 8 (9) or 9 (1), ventrally 8 (9) or 9 (1); procurrent rays dorsally 4 (1), 5 (3) or 6 (6), ventrally 4 (3), 5 (5) or 6 (2).

Lateral line incomplete; 22 (1), 23 (4) or 24 (5) scales in lateral series, which runs almost straight to caudal fin base, piercing anteriormost 5 (8) to 6 (2) scales. Scales in transverse row ½3/1/3½, predorsal scales 9, prepelvic scales 9 (2) or 10 (8), preanal scales 15 (1), 16 (3) or 17 (6), circumpeduncular scales 12. Pelvic axillary scale present, reaching to ¼ adpressed pelvic-fin length.

Osteology. Four supraneurals (1); predorsal neural spines 5 (1). First pterygiophore of dorsal fin inserted between 9th and 10th vertebrae ( Figure 2 A). Weberian apparatus constitutes first four vertebrae. Predorsal vertebrae including weberian apparatus 9 (1). Total number of vertebrae 4 + 26, with 4+13 abdominal and 13 caudal vertebrae (1). Infraorbital 3 deep, partially overlapping the cheek and preoperculum ( Figure 2 B); postepiphysial fontanelle absent ( Figure 2 C). Gill rakers simple, acuminate, 3 on epibranchial, one at angle and 13–14 (2) on ceratobranchial region. Last unbranched dorsal-fin ray serrated posteriorly with 11 (2), 12 (6), 13 (1) or 15 (1) pairs of serrae on its distal half, 1 (6) to 2 (4) serrae on apical half ( Figure 2 D). Caudal fin with six hypurals and one parhypural, last three caudal vertebrae support caudal fin ( Figure 2 E). Free uroneural absent, last neural spine on compound centrum small, stunted. Neural and haemal spines of the 2nd and 3rd pleural centra well developed, equally supporting caudal peduncle. Paired neural and haemal spines on 3rd pleural centra.

Coloration in preservative. For general appearance see Figure 1 ; body above lateral-line scale row dark brown; snout, head, dorsum dark brown; lower lip, cheek, opercular region below inferior border of eye cream; ventral region uniformly cream white. Body with one dark black humeral spot (10), overlapping 3rd and 4th lateral-line scales, extending one scale above lateral-line row (10); two black blotches on caudal peduncle, first overlapping 16th and 17th (3) or 17th and 18th (7) scales of lateral series, second overlapping 20th–21st (3) or 21st–22nd (2) scale of lateral series ( Figure 3 ), hazy in some preserved specimens (5). Dorsal fin usually without any color bands or blotches but in breeding males sometimes studded with two rows of indistinct minute black spots. Anal and caudal fins hyaline, without any color bands or spots. Pectoral and pelvic fins lightly pigmented with melanophores. Each body scale bordered with black pigmentation.

Coloration in life. Fresh specimens ( Figure 4 ) with body iridescent silver, each scale bordered with black pigmentation. Position of humeral spot and caudal blotches same as described for preserved specimens, first caudal peduncle blotch more distinct than second in fresh specimens. Second blotch on caudal peduncle distinct in freshlycollected live specimens, but disappears immediately after collection and in stressed condition. Dorsal fin usually hyaline without any markings but in breeding male studded with two rows of indistinct minute black spots. Pectoral, pelvic and anal fins hyaline. Pectoral and pelvic fins with scattered melanophores. Caudal fin colorless. Sclera uniform iridescent silver in females and immature males, red in breeding males. Opercular and infraorbital region studded with black spots.

Distribution. Pethia longicauda is currently known only from its type locality ( Figure 5 ) located in the upstream catchments of the east-flowing Hiranyakeshi River near Gavse-Ajara, Kolhapur District, Maharashtra, India.

Habitat. Pethia longicauda occurs in flooded temporary pools, riffles and runs with boulders and gravel as substratum ( Figure 6 ) with riparian vegetation. Co-occurring fishes included species of Salmostoma , Devario , Danio , Rasbora and Acanthocobitis .

Etymology. The species name ‘ longicauda ’ is Latin for ‘long tail’ and is named for the characteristic long caudal peduncle in the species. Gender feminine.

Common name. Long-tailed Pethia .

Phylogenetic position. Model test suggested best fit nucleotide substitution model to be Tamura & Nei (1993) model with gamma distribution and invariant sites (TN93+G+I, BIC = 15439.70, lnL = -6879.61, G = 0.79, I = 0.43). Pethia longicauda was nested within the clade of Pethia ( Figure 7 ) conforming its generic status, but was genetically distinct from the other Pethia species for which genetic data are available.

Figures

FIGURE 1. Pethia longicauda, holotype, BNHS FWF 96, 36.0 mm SL.

FIGURE 2. Osteology of Pethia longicauda (A) Cleared and stained specimen BNHS FWF 99 (female); (B) circumorbital series (So, supraorbital; IO 1 - 5, infraorbitals 1 - 5; Pop, preopercle); (C) dorsal view of orbital region of cranium (F, frontal; Pa, parietal ;; Sc, supraorbital sensory canal); (D) last unbranched dorsal-fin ray; and (E) caudal skeleton (CC, compound centrum; Ep, epural; H 1 - 6, hypurals 1 - 6; Ph, parhypural; Pls, pleurostyle; PU 2 - 3, preural centra 2 - 3).

FIGURE 3. Pethia longicauda, holotype, BNHS FWF 96, 36.0 mm SL, showing distribution of prominent body pigmentation.

FIGURE 4. Pethia longicauda, uncatalogued specimen, showing colour in life. Second blotch on caudal peduncle was distinct in freshly-collected specimens, but disappeared shortly after collection.

FIGURE 5. Map showing type locality of Pethia longicauda in the northern part of the Western Ghats mountain ranges.

FIGURE 6. Habitat at type locality of Pethia longicauda.

FIGURE 7. Phylogenetic position of Pethia longicauda based on maximum likelihood method. Values along the nodes are percent bootstraps for 1000 iterations. Garra species are used as outgroup.

Tables

TABLE 1. Morphometric characters and meristics of Pethia longicauda holotype (BNHS FWF 96) and paratypes (BNHS FWF 97 – 100, WILD- 14 - PIS- 073 – 075, ZSI-WRC P / 3950 – 51).

Characters	Holotype	Paratypes (n= 9)
Morphometric data Total length (mm) Standard length (SL, mm)	44.8 36.0	Mean (s.d.) Range 42.2 (3.7) 36.4−48.5 33.5 (2.5) 30.1−37.7
%SL Head length (HL) Head depth Head width	25.8 22.3 14.5	27.2 (1.8) 25.1−30.4 20.9 (2.2) 17.4−23.3 15.1 (0.9) 13.8−16.3
Body depth Body width at dorsal-fin origin Body width at anal-fin origin Pre-dorsal distance	32.3 19.1 13.9 43.0	33.1 (2.6) 29.1−37.2 16.8 (2.4) 13.2−19.8 11.2 (2.1) 7.4−13.8 49.5 (1.6) 47.0−51.5
Dorsal to hypural distance Prepelvic distance Preanal distance Prepectoral distance	47.5 46.7 68.7 26.7	52.5 (1.5) 50.7−54.8 46.8 (1.6) 44.7−50.4 68.6 (1.2) 66.9−70.5 26.6 (2.2) 23.9−31.0
Dorsal-fin length Dorsal-fin spine length Length of dorsal-fin base Pectoral-fin length	22.1 19.2 14.3 18.1	22.9 (1.7) 20.1−24.9 17.6 (2.1) 15.1−21.3 14.8 (1.5) 12.3−16.9 19.3 (1.3) 17.5−21.3
Anal-fin depth Caudal-peduncle length Caudal-peduncle depth	15.7 19.0 13.4	15.5 (1.6) 12.6−17.2 22.6 (2.3) 19.4−25.6 14.0 (1.1) 12.6−16.3
% HL Head depth Head width Snout length	86.3 56.4 24.2	77.0 (6.5) 68.5−85.3 55.7 (5.3) 47.9−64.2 25.6 (3.3) 20.1−29.7
Eye diameter Inter-orbital width Meristic data	27.4 43.4	28.1 (2.7) 23.5−31.4 39.3 (4.7) 31.6−45.1
Lateral-line scales Number of lateral-line pores Last unbranched dorsal-fin serrae Transverse scale rows	23 5 13 ½3/1/3½	22−24 5−6 11−15 ½3/1/3½
Predorsal scales Prepelvic scales Preanal scales Circumpeduncular scales Dorsal-fin rays	9 10 17 12 iii 8	9 9−10 15−17 12 iii 8
Pectoral-fin rays Pelvic-fin rays Anal-fin rays	i 12 i 7 iii 5	i 11−13 i 7 iii 5
Caudal-fin rays (procurrent) Caudal-fin rays (principal)	4+4 9+8	4−6+4−6 8−9+8−9