Schistura phamhringi, Shangningam, Bungdon, Lokeshwor, Yumnam & Vishwanath, Waikhom, 2014

Shangningam, Bungdon, Lokeshwor, Yumnam & Vishwanath, Waikhom, 2014, Schistura phamhringi, a new stone loach from Chindwin Basin in Manipur, India (Cypriniformes: Nemacheilidae), Zootaxa 3786 (2), pp. 181-191 : 182-188

Schistura phamhringi , new species

( Fig. 1 )

Holotype. MUMF 11157, 49.8 mm SL, male ( Fig. 1 A-C); India: Manipur: Chandel District: Dutah Stream, tributary of Yu River near Larong Village (Chindwin-Irrawaddy basin); 24°15'3.87"N, 94°14'58.55 "E, 283 m above sea level, BD Phamhring Anal, 19 April 2013.

Paratypes. MUMF 11156, 60.8 mm SL, male; MUMF 11159–11161, 56.0– 58.6 mm SL, 3 males; MUMF 11163, 38.5 mm SL, male; MUMF 11164, 38.5 mm SL, female ( Fig. 1 D); MUMF 11165, 38.3 mm SL, male; data same as holotype. ZSI FF 5065, 31.3–53.7 mm SL, 2 males (41.5–53.7 mm SL) and 1 female (31.3 mm SL); data same as holotype. One paratype ( MUMF 11161, 56.0 mm SL) dissected for examination of intestine and air bladder.

Diagnosis. Schistura phamhringi is distinguished from all other species of Schistura by the following combination of characters: 6–7 black saddles, each continued on both flanks forming a broad diamond-shaped black bar with narrow ventral margins; bars superimposed on a grey stripe along lateral line; upper lip with numerous melanophores arranged densely; black basicaudal bar arc-shaped; complete lateral line; processus dentiformis broad; prominent oar-like suborbital flap on male.

Description. General appearance as in Fig. 1 . Morphometric data are in Table 1 . Body relatively small, moderately elongate, slightly deeper anterior to dorsal-fin origin, 1.2 times deeper than wide; and compressed posteriorly. Dorsal profile of body evenly elevated from tip of snout to dorsal-fin origin, then straight to end of dorsal-fin base, elevated towards middle of caudal peduncle, forming a very low dorsal adipose crest. Head depressed, 1.1–1.2 times wider than deep, oblong. Snout short, dorsal head length 2.1 times snout length; rounded. Interorbital distance moderate, about 55.7% of head width at middle of eyes.

Dorsal fin with 4 simple and 8½ branched rays, its origin anterior to pelvic-fin origin, slightly nearer to tip of snout. Anterior margin of dorsal fin convex, posterior margin straight. Second branched dorsal-fin ray longer than remaining branched rays. Anal fin with 3 simple and 5½ branched rays, not reaching caudal-fin base, leaving gap of eye diameter. Pectoral fin sub-acuminate, with 1 simple and 11 branched rays, reaching midway to pelvic-fin origin. Pelvic fin sub-acuminate, with 1 simple and 7 branched rays, its origin vertical through base of dorsal branched ray 2 or 3, not touching anus when adpressed, leaving more or less a gap of eye diameter. Axillary pelvicfin lobe well developed. Caudal fin with 9+8 branched rays; deeply emarginate; lobes subequal, lower lobe 1.1 times longer than upper lobe. Caudal peduncle 1.1–1.2 times longer than deep, with a very low dorsal and ventral adipose crest on posterior half. Largest known size 60.8 mm SL (MUMF 11156).

Body completely covered with deeply embedded, minute cycloid scales except on chest and belly in front of anal-fin origin. Lateral line complete, with 84–99 pores. Cephalic lateralis system with 6–8 supraorbital, 3+9 infraorbital, 9–10 preorperculo-mandibular and 3 supratemporal pores. Unculi blunt, low on outer face of both jaws but high on margin and inner face, arranged side-by-side like tiles ( Fig. 2 ). Taste buds pyramidal, arranged sparsely on lips and barbels. Tubercles on lateral free margin of suborbital flap on male.

Anterior nostril pierced anteriorly with a low leaf-like pointed tube. Mouth arched, 1.3–1.9 times wider than long. Lips fleshy. Lower lip with deep median interruption with 7–8 furrows on outer edge ( Fig. 3 ). Upper lip thin laterally and broad medially, a deep median incision, and very low regular furrows on entire lip (furrows deeper near corners of mouth). Processus dentiformis prominent, broad. Lower jaw with shallow median notch.

Barbels: three pairs, inner rostral barbel not reaching corner of mouth; outer one reaching past base of maxillary barbel. Maxillary barbel reaching vertical through middle of eye. Free posterior chamber of air bladder small, spherical, concealed beneath manubrium ( Fig. 4 ). Intestine with small loop near stomach ( Fig. 5 ).

Sexual dimorphism. Males with prominent oar-like suborbital flap ( Fig. 6 ).

Colour. In fresh specimens: Body with 6–7 black saddles (2–3 pre-dorsally, 2 sub-dorsally and 2 postdorsally), each continued down flanks forming a broad diamond-shaped black bar with narrow ventral margins except pre-dorsal and anterior sub-dorsal bars with diffused ventral margins. Bars superimposed on a grey stripe along lateral line. All bars extending beneath lateral line, not meeting their antimeres ventrally except 2 post-dorsal bars. Body background colour grey on dorsum (dark grey on pre-dorsal) and dorsolaterally; dull white ventrally. Dorsal and ventral margin of caudal peduncle dull white. Interspaces wider than saddles on dorsum. Interspaces about half of width of each bar on dorsolateral flank, and much wider on ventral flank. Head dark grey dorsally and laterally; light grey to dull white with sparsely arranged melanophores ventrally. Upper lip with numerous melanophores arranged densely, covering about 70% of its area. A black spot at bases of simple and first two branched rays. A row of dark grey spots on last simple and all branched dorsal-fin rays at midway, near branching points on branched rays. First five pectoral-fin rays dark grey, remaining rays hyaline. Basicaudal bar black, incomplete, arc-shaped, medial, leaving a gap of about half of eye diameter on upper and lower extremities of caudal-fin base. A backwardly directed black bar from basicaudal bar on first three dorsal procurrent rays. Proximal portion of caudal-fin rays streaked grey, appearing as a blending from basicaudal bar, prominent on dorsal and ventral portion. Caudal-fin rays light grey to dark grey posteriorly.

In 10% buffered formalin: all bars and saddles black; background colour on dorsal dark grey to light grey, ventral and ventrolateral portions dull white to white. Interrradial membranes of fins dull white to white. Distribution. Known only from Dutah Stream, tributary of Yu River (Chindwin basin), Chandel District, Manipur, India ( Fig. 7 ).

Habitat. The species inhabitants cool, clean, swift-flowing shaded freshwater streams which flow over a substrate of gravel, cobble and boulders ( Fig. 8 ). Topotypic specimens were collected from a stream near Larong Village in Chandel District, Manipur, India (the Chindwin-Irrawaddy basin), among small pebbles, in slow current. Other species occurring with Schistura phamhringi were Cyprinidae : Barilius ngawa , Devario acquipinnatus , Neolissochilus stracheyi , Poropuntius burtoni , Garra paralissorhynchus ; Psilorhynchidae : Psilorhynchus ngathanu ; Nemacheilidae : Schistura khugae , S. reticulata ; Sisoridae : Glyptothorax granulus , G. ventrolineatus ; Mastacembelidae : Mastacembelus armatus ; and Channidae : Channa gachua .

Etymology. The species is named in memory of BD Phamhring Anal, recently deceased and collector of the specimens of the new species.

Figures

FIGURE 1. Schistura phamhringi, n. sp. A) lateral, B) dorsal, and C) ventral views of holotype, MUMF 11157, 49.8 mm SL, male; D) paratype, MUMF 11164, 35.4 mm SL, female, lateral view.

FIGURE 2. Oromandibular structures of Schistura phamhringi (MUMF 11161, 56.0 mm SL). A) Ventral surface of head; B) magnified ventral surface of head; C) closeup view of box i in A, showing taste buds on rostral barbel; D) closeup view of box ii in B, showing unculi on lower jaw. TB- taste bud, UC- unculi, LJ- lower jaw, LL- lower lip, UL- upper lip, RB- rostral barbel.

FIGURE 3. Lip structure of Schistura phamhringi (MUMF 11157, 49.8 mm SL). Scale bar = 1 mm.

FIGURE 4. Air bladder of Schistura phamhringi (MUMF 11161, 56.0 mm SL) showing free posterior chambers. Scale bar = 1 mm.

FIGURE 5. Coiling pattern of intestine of Schistura phamhringi. Scale bar = 1 mm.

FIGURE 6. Lateral view of head of Schistura phamhringi (MUMF 11157, 49.8 mm SL, male) showing suborbital flap.

FIGURE 7. Map showing type locality (solid star) of Schistura phamhringi.

FIGURE 8. Manipur: Dutah Stream at Larong Village (Chindwin-Irrawaddy basin), collection site of Schistura phamhringi; looking downstream and to the east.

Tables

TABLE 1. Morphometric characters of Schistura phamhringi (holotype, MUMF 11157) and nine paratypes ─ seven in MUMF, Manipur (MUMF 11156 – 11165) and three in ZSI Kolkata (ZSI FF 5065). Values of holotype are included in ranges.

	holotype	range	mean	SD
Standard length (mm)	49.8	31.3–60.8
In percentage of standard length
Body depth at dorsal-fin origin	16.7	13.3–16.8	15.6	0.2
Head depth at nape	13.6	11.3–14.0	12.9	0.2
Head depth at eye	11.2	10.0–11.9	10.9	0.5
Lateral-head length	24.3	22.0–25.1	23.5	0.7
Dorsal-head length	22.1	19.2–23.0	21.1	1.4
Caudal-peduncle length	15.7	14.3–18.4	15.7	1.6
Caudal-peduncle depth	13.1	11.7–13.8	12.7	0.1
Pre-dorsal length	48.4	48.2–49.8	48.8	0.6
Pre-pelvic length	49.8	47.8–52.1	51.3	0.9
Pre-anus length	69.5	68.2–72.3	69.9	0.7
Pre-anal length	77.1	74.4–79.3	76.2	0.9
Dorsal-fin height	14.9	13.3–15.8	14.8	0.9
Anal-fin depth	14.3	12.0–17.5	14.4	0.0
Pectoral-fin length	21.5	19.2–22.6	21.2	1.1
Pelvic-fin length	18.3	15.7–19.3	17.9	0.6
Maximum head width at cheek	16.1	13.0–16.1	14.7	0.5
Body width at anal-fin origin	10.8	9.0–10.8	9.9	0.4
Body width at dorsal-fin origin	14.7	12.1–14.7	13.3	0.7
In percentage of dorsal head length
Snout length	42	41–55	47.7	4.9
Interorbital distance	35	28–37	33.3	3.1
Eye diameter	16	14–18	16.0	1.3
Mouth gape width	34	29–42	33.2	4.2
Head depth at eye	51	46–56	51.9	3.0
Head depth at nape	62	55–72	61.6	5.8
Head width at nares	47	42–55	49.2	4.1
Maximum head width at cheek	73	61–79	70.0	6.5