Pseudolaguvia viriosa, Ng, Heok Hee & Tamang, Lakpa, 2012

Ng, Heok Hee & Tamang, Lakpa, 2012, Pseudolaguvia viriosa, a new catfish (Teleostei: Sisoridae) from north-eastern India, Zootaxa 3522, pp. 81-88 : 82-86

Pseudolaguvia viriosa sp. nov.

( Fig. 1 )

Type material. Holotype: ZSI V/ APRC /P-524, 26.0 mm SL; India: Arunachal Pradesh, East Siang district, Sille River, approximately 1 km upstream from RCC bridge, about 10 km from Ruksin and about 26 km before Pasighat, 27°52'37.6"N 95°18'18.0"E; L. Tamang, 28 October–2 November 2011.

Paratypes: RGUMF 0 0 7 (13), 23.1–27.2 mm SL; data as for holotype.

Diagnosis. Pseudolaguvia viriosa differs from all congeners except P. m u r i c a t a in having longer dorsal- (23.4–29.0% SL vs. 11.3–21.7) and pectoral-fin (26.9–32.9% SL vs. 15.9–27.5) spines. It can be further distinguished from P. m u r i c a t a in having a deeper body (depth at anus 16.9–19.0% SL vs. 11.7–16.5), longer caudal peduncle (14.8–17.7% SL vs. 12.6–15.7), one or more distinct pale bands encircling the body (vs. bands indistinct or absent), and a dorsal spine with anterior edge smooth or with rugose surface only on distal third of spine (vs. distinct serrations throughout entire length of spine). The following combination of characters serve to further distinguish P. v i r i o s a from congeners: eye diameter 10–15% HL, interorbital distance 35–38% HL, head width 21.5–23.5% SL, thoracic adhesive apparatus reaching beyond base of last pectoral-fin ray, length of adiposefin base 12.5–15.4% SL, caudal peduncle depth 7.4–9.8% SL, caudal-fin length 26.5–32.4% SL, and 28–29 vertebrae.

Description. Biometric data as in Table 1 . Head depressed, body moderately compressed. Dorsal profile rising evenly from tip of snout to origin of dorsal fin, then sloping gently ventrally to end of caudal peduncle. Ventral profile flat to anal-fin base, then sloping gently dorsally to end of caudal peduncle. Supraoccipital spine reaching nuchal shield. Weberian lamina well developed, approximately same length as supraoccipital spine and extending parallel to either side of spine. Eye ovoid, horizontal axis longest; located entirely in dorsal half of head. Orbit with free margin. Gill openings narrow, extending from posttemporal to isthmus. Branchiostegal membranes united at isthmus. Caudal peduncle short and moderately slender. Anus and urogenital openings located at vertical through middle of adpressed pelvic fin. Skin prominently tuberculate, with conical tubercles particularly prominent on dorsal third of head and body. Lateral line complete and midlateral. Vertebrae 13+15=28* (8), 14+14=28 (4) or 14+15=29 (1). Abdomen with thoracic adhesive apparatus consisting of longitudinal, unculiferous ridges arranged in elliptical field and with prominent central median depression. Adhesive apparatus extending to midway between base of last pectoral-fin ray and pelvic-fin origin.

Mouth small, inferior and with papillate lips; upper jaw projecting beyond lower jaw. Oral teeth small and in irregular rows on all tooth-bearing surfaces. Premaxillary tooth band consisting of single broad lunate patch across midline; with conical teeth and not exposed when mouth is closed. Dentary tooth band narrow, with conical teeth. Barbels in four pairs. Nasal barbel very short and broad, extending to midway between its base and anterior orbital margin. Maxillary barbel slender, with broad skin flap at base and extending to base of pectoral-fin spine. Outer mandibular barbel with broad skin flap on dorsal margin and extending to base of pectoral-fin spine; inner mandibular barbel broad and shorter, reaching to vertical through midway between posterior orbital margin and base of pectoral-fin spine.

Dorsal fin located about two-fifths along body; with 5 (14) rays and straight margin. Dorsal-fin spine long, flattened, slightly curved and robust; adpressed spine extending posteriorly to vertical through origin of anal fin. Anterior margin of spine smooth in some individuals, with rugose surface on distal third in other individuals; posterior margin with 7–11 serrations.

Pectoral fin with stout, blade-like spine, sharply pointed at tip, and with 5,i (3), 6 (2), 5,ii (5) or 6,i* (4) rays. Anterior spine margin with 13–27 small serrations. Posterior spine margin with 8–11 serrations. Pectoral-fin margin straight anteriorly and posteriorly. Coracoid with moderate posterior processes, extending to midway between base of last pectoral-fin ray and pelvic-fin origin.

Pelvic-fin origin at vertical through base of last dorsal-fin ray. Pelvic fin with i,5 (14) rays and straight margin; tip of adpressed fin not reaching anal-fin origin.

Adipose fin short, posterior end deeply incised, located above anal-fin base. Anal fin with iv,6 (4), iii,8 (3), iv,6,i (4) or iv,7* (3) rays, and straight anterior and slightly convex posterior margin.

Caudal peduncle moderately slender. Caudal fin deeply forked, with i,7,7,i (14) principal rays; upper and lower lobes pointed, with lobes of equal length but lower lobe slightly broader than upper. Procurrent rays symmetrical, extending only slightly anterior to fin base.

Coloration. In 70% alcohol: dorsal surface and sides of head and body brown. Belly, chest and ventral surfaces of head and body cream. Series of three cream spots on dorsal and lateral surfaces of head and anterior portion of body: one at tip of supraoccipital spine, second at tips of nuchal plate elements and third along posterolateral exposed surface of Weberian lamina. Body with irregular cream band encircling it between dorsal and adipose fins. Caudal peduncle with small irregular cream patches on sides, coalescing to form thin irregular band in some individuals. Dorsal and ventral surfaces of caudal peduncle with elongate cream patch. Almost all of dorsal fin brown, with very thin, irregular hyaline distal margin. Anal fin with brown base on anterior half and irregular subdistal band; subdistal band reduced to spot on anterior portion of fin in some individuals. Small brown spot on base of last anal-fin ray. Pelvic fin hyaline with brown spot at base and transverse brown band along middle third of fin; brown band reduced to series of brown spots on first three fin rays in some individuals. Pectoral fin with brown base and irregular transverse brown subdistal band. Caudal fin with large brown spot at distal third of each lobe, hyaline tips and small brown spots randomly distributed in middle of median principal rays. Adipose fin brown at base, paler along dorsal and posterior parts. Nasal, maxillary and mandibular barbels cream, annulated with brown bands.

Distribution and habitat. This species is known from the Sille River in Arunachal Pradesh, India ( Fig. 2 ). The Sille River is a tributary of the Siang River, which together with the Dibang and Lohit rivers comprises the upper-middle Brahmaputra River drainage in India. The type series was caught in shallow (depth ca. 30–50 cm), clear and swift flowing water by mosquito net. The fish were found living amongst crevices of small to medium size stones, pebbles, and cobbles that comprise the substrate. The river is shallow and swiftly flowing, with vegetation on the bank consisting mostly of grasses and shrubs. The following fish species were also encountered at this locality: Barilius bendelisis (Cyprinidae) , Barilius vagra (Cyprinidae) , Chagunius chagunio (Cyprinidae) , Garra annandalei (Cyprinidae) , Pethia conchonius (Cyprinidae) , Pethia ticto (Cyprinidae) , Tor tor (Cyprinidae) , Psilorhynchus balitora (Psilorhynchidae) , Aborichthys elongatus (Nemacheilidae) , Acanthocobitis botia (Nemacheilidae) , Pangio pangia (Cobitidae) , Olyra longicaudata (Bagridae) , Amblyceps arunachalensis (Amblycipitidae) , Badis singenensis (Badidae) , Glossogobius giuris (Gobiidae) , and Mastacembelus armatus (Mastacembelidae) .

Etymology. The specific epithet is the Latin adjective viriosus, meaning strong or robust. This name is used in reference to the relatively deep, robust body and long fin spines of this species when compared to many congeners.

Besides P. v i r i o s a, seven species of Pseudolaguvia are known from the Brahmaputra River drainage (Ng, 2009): P. ferula , P. ferruginea , P. f l a v i d a, P. foveolata , P. m u r i c a t a, P. r i b e i ro i and P. shawi . Except for P. m u r i c a t a, P. v i r i o s a differs from all these congeners in having longer dorsal- (23.4–29.0% SL vs. 11.3–18.7) and pectoral-fin spines (26.9–32.9% SL vs. 16.3–24.3); the characters that diagnose P. viriosa from P. m u r i c a t a are as outlined in the diagnosis. Pseudolaguvia viriosa is further distinguished from P. ferula in having a wider head (21.5–23.5% SL vs. 17.1–19.9), a deeper body (depth at anus 16.9–19.0% SL vs. 12.1–13.8), shorter caudal peduncle (14.8–17.7% SL vs. 18.2–19.4), a longer caudal fin (26.5–32.4% SL vs. 21.7–26.6) and distinct pale bands encircling the body (vs. absent), from P. ferruginea , P. f l a v i d a and P. f o v e o l a t a in having a deeper body (depth at anus 16.9–19.0% SL vs. 10.5–12.4), a longer caudal fin (26.5–32.4% SL vs. 21.3–26.2) and fewer vertebrae (28–29 vs. 30–33), and from P. foveolata in having a shorter adipose-fin base (12.5–15.4% SL vs. 24.0–24.6) and a thoracic adhesive apparatus reaching beyond (vs. not reaching) the base of the last pectoral-fin ray. It further differs from P. r i b e i ro i in having a dorsal spine with anterior edge smooth or with rugose surface only on distal third of spine (vs. distinct serrations throughout entire length of spine), deeper body (depth at anus 16.9–19.0% SL vs. 13.6–14.8) and caudal peduncle (7.4–9.8% SL vs. 6.6–7.2), and from P. s h a w i in having a deeper body (depth at anus 16.9–19.0% SL vs. 13.1–16.6) and shorter adipose-fin base (12.5–15.4% SL vs. 15.9–20.3) and longer caudal fin (26.5–32.4% SL vs. 21.6–26.0).

Pseudolaguvia viriosa further differs from P. inornata in having a wider interorbital distance (35–38% HL vs. 30–34), deeper body (depth at anus 16.9–19.0% SL vs. 13.9–16.1) and distinct pale bands encircling the body (vs. absent), from P. s p i c u l a in having a wider interorbital distance (35–38% HL vs. 28–32), deeper body (depth at anus 16.9–19.0% SL vs. 12.8–16.8), shorter adipose-fin base (12.5–15.4% SL vs. 14.7–17.1) and fewer vertebrae (28–29 vs. 30–32), and from P. virgulata in having a shorter caudal peduncle (14.8–17.7% SL vs. 18.2–20.2) and lacking (vs. having) pale, narrow longitudinal stripes running along the sides of the body. It is further distinguished from P. kapuri in having a dorsal spine with anterior edge smooth or with rugose surface only on distal third of spine (vs. distinct serrations throughout entire length of spine), deeper body (depth at anus 16.9–19.0% SL vs. 12.7–15.2), shorter adipose-fin base (12.5–15.4% SL vs. 17.1–18.9) and pelvic fin (13.1–15.6% SL vs. 15.3–17.9), and longer caudal fin (26.5–32.4% SL vs. 22.5–25.8), from P. tenebricosa in having a wider interorbital distance (35–38% HL vs. 28–30) and deeper body (depth at anus 16.9–19.0% SL vs. 12.7–14.4), from P. tuberculata in having a wider interorbital distance (35–38% HL vs. 28–34), deeper body (depth at anus 16.9–19.0% SL vs. 11.2–13.7) and shorter adipose-fin base (12.5–15.4% SL vs. 16.8–22.7). Pseudolaguvia viriosa differs from P. austrina in having a larger eye (10–15% HL vs. 4–8), longer (14.8–17.7% SL vs. 8.8–14.7) and more slender (7.4–9.8% SL vs. 10.3–14.7) caudal peduncle, fewer vertebrae (28–29 vs. 33) and distinct pale bands encircling the body (vs. absent).

Figures

FIGURE 1. Pseudolaguvia viriosa, RGUMF 0 0 6, holotype, 26.0 mm SL; dorsal, lateral and ventral views.

FIGURE 2. Map showing collection localities of Pseudolaguvia viriosa.

Tables

TABLE 1. Biometric data for Pseudolaguvia viriosa (n = 14)

	Holotype	Range	Mean±SD
%SL
Predorsal length	43.5	41.1–47.1	44.4±1.88
Preanal length	67.7	67.7–71.9	70.5±1.81
Prepelvic length	52.3	52.3–56.9	55.2±1.71
Prepectoral length	23.8	23.8–28.6	26.2±1.76
Length of dorsal-fin base	14.6	14.6–18.0	16.5±1.51
Dorsal-fin spine length	23.5	23.4–29.0	24.9±2.11
Length of anal-fin base	17.7	13.4–17.7	15.9±1.49
Pelvic-fin length	13.1	13.1–15.6	14.7±0.88
Pectoral-fin length	29.2	29.2–36.6	31.9±3.48
Pectoral-fin spine length	26.9	26.9–32.9	28.9±2.20
Caudal-fin length	28.5	26.5–32.4	28.8±2.31
Length of adipose-fin base	15.4	12.5–15.4	14.2±1.26
Dorsal to adipose distance	15.4	11.7–15.4	13.7±1.78
Post-adipose distance	16.5	14.6–18.6	15.8±1.56
Caudal peduncle length	17.7	14.8–17.7	16.4±1.28
Caudal peduncle depth	8.8	7.4–9.8	8.8±0.88
Body depth at anus	16.9	16.9–19.0	18.1±0.86
Head length	33.1	28.5–33.1	30.9±1.72
Head width	23.5	21.5–23.5	22.6±0.76
Head depth	17.7	16.0–20.8	18.5±1.63
%HL
Snout length	50	50–54	53±1.5
Interorbital distance	35	35–38	36±1.5
Eye diameter	11	11–15	12±2.3
Nasal barbel length	16	11–16	13±2.3
Maxillary barbel length	66	55–81	69±9.7
Inner mandibular barbel length	36	33–43	37±3.5
Outer mandibular barbel length	52	44–65	53±6.8
Discussion