Pseudolaguvia jiyaensis, Tamang, Lakpa & Sinha, Bikramjit, 2014

Tamang, Lakpa & Sinha, Bikramjit, 2014, Two new species of the South Asian catfish genus Pseudolaguvia from northeastern India (Teleostei: Sisoridae), Zootaxa 3887 (1), pp. 37-54 : 45-50

Pseudolaguvia jiyaensis , sp. nov.

( Fig. 5 )

Type material. Holotype: ZSI/V/ APRC /P-1034, 29.9 mm SL; India: Arunachal Pradesh, Lower Dibang Valley District, Jiya stream, near Bolik village, approximately 14 km from Roing towards Shantipur, Assam, 28°00.377'N 95°45.562'E; 149 m asl., B. Sinha & L. Tamang, 18 March 2014.

Paratypes: ZSI/V/ APRC /P-1035, 15, 25.6–31.2 mm SL; same data as holotype.

Diagnosis. Pseudolaguvia jiyaensis is distinguished from its congeners by having the thoracic adhesive apparatus almost reaching the pelvic-fin origin, and fewer vertebrae (25-27 vs. 28–34; except in P. tenebricosa and P. tuberculata ). It can be further distinguished from P. nubila , P. inornata , P. muricata , P. ferula , P. flavida , P. viriosa , P. virgulata , P. lapillicola , and P. assula by having a shorter dorsal-fin spine (11.9–15.0% SL vs. 15.7–29.0) and in addition to P. assula and P. foveolata (but not P. nubila and P. lapillicola ) by having a shorter pectoral-fin spine (16.6–19.8% SL vs. 20.2–35.7); and from P. muricata , P. virgulata , P. v i r i o s a, P. austrina , and P. assula by having a shorter pectoral fin (22.6–26.0% SL vs. 26.4–38.1).

Congeners from the Brahmaputra drainage system (see above additional differentiating characters outlined for P. ferula , P. v i r i o s a and P. m u r i c a t a): Pseudolaguvia jiyaensis is distinguished from P. magna by having a shorter body (25.6–31.2 mm SL vs. 31.9–46.7 mm) and shorter interdorsal distance (14.4–17.0% SL vs. 16.7–20.3), by the presence (vs. absence) of two prominent creamy bands on body, longer anal- (11.3–15.2 vs. 9.1–11.8) and adiposefin bases (13.8–18.0% SL vs. 10.7–14.2), and longer caudal fin (22.3–29.7% SL vs.19.9–23.7); from P. foveolata by having a shorter adipose-fin base (13.8–18.0 vs. 24.0), a longer predorsal (40.6–45.5% SL vs. 38.7), a longer pelvic fin (12.9–16.1% SL vs. 19.0) and head (30.3–33.3% SL vs. 26.7), deeper body at anus (14.8–18.4% SL vs. 11), and a narrower (vs. broader) cream (vs. yellowish) band on caudal peduncle (see Fig. 5 here and fig. 2 in Ng, 2005a); further from P. ferula by having a distinct (vs. faint) cream bands on body and a longer predorsal (40.6–45.5% SL vs. 36.3–40.4); from P. r i b ei roi by having a smooth (vs. serrated) anterior margin of dorsal-fin spine, deeper caudal peduncle (8.4–10.4% SL vs. 6.6–7.2), narrower (vs. broader) subdistal brown band on pelvic and anal fins, caudal fin median rays with a brown (vs. cream) patch on proximal part (see Fig. 5 here and fig. 7e in Ng, 2009); from P. s ha w i by having a narrower (26–32% HL vs. 35) interorbital width, caudal fin with a regular (vs. irregular) subdistal brown band and with a narrower (vs. broader) medial transverse cream band, and on the caudal peduncle (see Fig. 5 here and fig.7f in Ng, 2009); from P. ferruginea by having a longer prepectoral distance (24.2–27.7% SL vs. 18.3–24.5), a deeper body at anus (14.8–18.4% SL vs.10.5–12.4), pelvic and anal fins with a narrower (vs. broader) subdistal brown band and also smaller (vs. larger) proximal bands, and pelvic-fin tip extending almost to (vs. far from) anal-fin origin (see Fig. 5 here and fig. 1, Ng, 2009); from P. viri osa by having a narrower (26–32% HL vs. 35–38) interorbital width; and from P. m u r i c at a by having a longer caudal peduncle (16.0–20.7% SL vs. 12.6–15.7), more depressed head (depth 10.2–15.5% SL vs. 16.7–19.5), and shorter inner mandibular barbel (28–37% HL vs. 59–84).

Congeners from the Sittang and Irrawaddy river systems: Pseudolaguvia jiyaensis is distinguished from P. tenebricosa by having a longer prepectoral (24.2–27.7% SL vs. 20.6–23.0), head (30.3–33.3% SL vs. 26.6–29.6), and a shorter (vs. longer) adipose fin (see Fig. 1 a in Britz & Ferraris, 2003); and from P. tuberculata by having a shorter (vs. longer) adipose-fin base, not reaching (vs. reaching) dorsal-fin base.

Congeners from the Surma-Meghna River system: Pseudolaguvia jiyaensis is distinguished from P. spicula by having a longer predorsal (40.6–45.5% SL vs. 37.4–40.4) and head (30.3–33.3% SL vs. 26.0–28.8), and shallower head (10.2–15.5% SL vs. 15.6–19.1), distinct (vs. indistinct) cream bands on body, and caudal fin with a complete (vs. incomplete) hyaline medial bands across each lobe.

Congeners from the Kaladan River: Pseudolaguvia jiyaensis is distinguished from P. nubila by having a longer predorsal (40.6–45.5% SL vs. 36.6–40.6) and prepectoral (24.2–27.7% SL vs. 22.0–24.9), shorter dorsal spine (11.9–15.0% SL vs. 16.4–19.3) and anal-fin base (11.3–15.2% SL vs. 15.6–19.7), and shallower head (depth 10.2–15.5% SL vs. 15.3–18.9).

Congeners from Ganga drainage system (see above additional differentiating characters outlined for P. inornata , P. virgulata , and P. assula ): Pseudolaguvia jiyaensis is distinguished from P. inornata , P. virgulata and P. assula by the presence (vs. absence) of prominent cream bands on the body; further from P. inornata by having shorter maxillary (54–68% HL vs. 78–83) and inner mandibular (28–37% HL vs. 38–41) barbels, and in addition to P. flavida by having a deeper caudal peduncle (8.4–10.4% SL vs. 6.5–8.5); further from P. inornata and P. virgulata by having a shallower head (depth 10.2–15.5% SL vs. 15.9–19.4), shorter post-adipose distance (15.5–17.4% SL vs. 17.6–18.7; except in P. inornata ); further from P. f l av i da by having a longer pelvic fin (12.9–16.1% SL vs. 10.2), prepectoral (24.2–27.7% SL vs. 19.5), adipose-fin base (13.8–18.0% SL vs. 11) and head (30.3–33.3% SL vs. 27.6), and deeper body at anus (14.8–18.4% SL vs. 11); further from P. assula by having a broader (vs. narrower) thoracic adhesive apparatus (compare Fig. 6 here and fig. 2; Ng & Conway, 2013); from P. kapuri by having a smooth (vs. serrated) dorsal-spine margin, shorter adipose-fin base (13.8–18.0% SL vs. 17.1–20.6), smaller (vs. larger) cream patches on the anterior and posterior margins of adipose-fin, a narrower (vs. broader) cream band on the caudal peduncle and across the middle of the caudal fin, and caudal fin with smaller (vs. larger) hyaline tips (see Fig. 5 here and fig. 8 in Ng, 2009).

Congeners from Bharathapuzha River, Subramanya and Kumaradhara River (see above additional characters in the beginning outlined for this two species): Pseudolaguvia jiyaensis is differentiated from P. austrina and P. lapillicola by having a shorter interdorsal distance (14.4–17.0% SL vs. 29.2–32.7), and shorter nasal- (13–23% HL vs. 25–48) and maxillary barbels (54–68% HL vs. 77–106); from P. austrina by having a shorter pelvic fin (12.9–16.1% SL. vs. 16.0–20.9), longer caudal peduncle (16.0–20.7% SL vs. 8.8–14.7), and adpressed anal fin not reaching (vs. reaching) the lower procurrent caudal-fin rays; further from P. lapillicola by having a longer predorsal (40.6–45.5% SL vs. 39.5–41.8) and prepelvic (49.6–54.9% SL vs. 47.0–49.1), shorter adipose-fin base (13.8–18.0% SL vs. 21.2–23.9), deeper caudal peduncle (8.4–10.4% SL vs. 7.5–8.2), shallower head (depth 10.2–15.5% SL vs. 19.4–20.7), longer snout (47–55% HL vs. 34–42), cream-colored bands complete (vs. incomplete, covering only ventrolateral region below lateral line) across the body, a narrower (vs. broader) hyaline band across the middle of the caudal fin, smaller (vs. larger) cream–colored patches on tips of each lobe, and head and sides of body without (vs. with) numerous prominent brown and black spots.

Description. General body shape as in Figure 5 ; morphometric data are provided in Table 2 . Head dorsoventrally depressed, moderately broad, degree of depression increasing towards snout margin, lateral profile gently sloping from insertion of pectoral fin to snout tip, side and dorsum scattered with numerous small keratinized tubercles, those on occipital region minute. Snout margin moderately rounded. Humero-cubital and scapular processes well-developed. Body with numerous series of tubercles except on thoracic adhesive apparatus. Fleshy bases of adipose fin also with tubercles. Rayed portions of fins without tubercles. Eye small, ovoid, located entirely on dorsal half of head, situated slightly closer to end of operculum than snout tip. Mouth subterminal, consisting of fleshy papillated lips, region between lower lip and thoracic adhesive apparatus densely papillated, upper jaw projecting over lower jaw, premaxillary tooth band partially visible when mouth closed. Gill opening wide, extending obliquely from posttemporal to isthmus. Supraoccipital spine terminating very close to nuchal shield. Upper lip continuing into maxillary barbel, barbel bases connected to sides of head through small triangular dermal flap at base, just above corner of mouth. Thoracic adhesive apparatus long (about twice as long as broad), extending close to pelvic-fin origin ( Fig. 6 ). Lateral line complete, midlateral, vertebrae 25–27 in four specimens.

Body moderately elongate, greatest depth at dorsal-fin origin, deeper than wide, moderately compressed anteriorly, degree of compression increasing from insertion of dorsal fin to caudal-fin base. Dorsal profile overall evenly rising to dorsal-fin origin, gently decreasing posteroventrad thereafter to caudal-fin base. Ventral profile almost horizontal from mouth to pelvic-fin origin, thereafter very gently ascending towards caudal-fin base.

Maxillary barbel with broad base, base extending posterior to level of mid nostril, tip almost reaching pectoralfin origin. Nasal barbel arising from internarial septum, extending at least halfway to anterior orbital margin. Outer mandibular barbel slender with pointed tip and reaching pectoral-fin origin. Inner mandibular barbel shorter, extending only half as far as outer mandibular barbel tip, originating from same level as outer mandibular barbel base. Anus and urogenital opening situated slightly nearer to anal-fin origin than to pelvic-fin origin.

Thoracic adhesive apparatus moderately elliptical with a prominent central median depression, anterior portion moderately wide, narrow posteriorly, extending close to pelvic-fin origin (its length twice its breadth, sometimes slightly less), lateral margin of thoracic adhesive apparatus not reaching base of pectoral fin.

Dorsal fin located about two-fifths of standard length along body, with 5,i*(15) or 6 (1) rays and straight margin, middle of base situated midway between snout tip and mid-adipose-fin base, at near vertical to middle of pectoral- and pelvic-fin origins; spine rigid, pointed, straight, laterally compressed, anterior and posterior margin smooth. Erect spine extends only to perpendicular from body axis.

Adipose fin short, roughly triangular, anterior margin straight, posterior margin straight to slightly convex with incised posterior end, originating slightly anterior to vertical at pelvic-fin origin.

Pectoral fin with a dorsoventrally depressed, strong, sharply pointed spine, with 6,i*(14) or 7,i (2) rays. Anterior margin of spine with 9–12 moderate serrae, distally directed, size of serrae decreasing to minute or granular towards base; posterior margin with 6–7 strong, large serrae, size decreasing towards base; tip of spine soft and flexible, accompanied by soft anterior and posterior serrae; tip of adpressed fin extending to vertical through base of third to last ray of dorsal fin. Pectoral spine movable backwards only (perpendicular to horizontal laterally); pectoral fins not plaited. Pectoral girdle with prominent postcoracoid processes, hidden beneath skin, extending to midway between its base and pelvic-fin origin.

Pelvic fin soft, with i,4,i*(14) or i,5 (2) rays, located almost at middle of body; its origin almost vertically beneath base of antepenultimate dorsal-fin ray. Anterior margin slightly convex, posterior obliquely straight; first and second branched rays longest; adpressed fin extending beyond anus, but never reaching anal-fin origin; tip of last ray reaching middle to posterior margin of anus in adult specimens, extending slightly past anus in juveniles.

Caudal fin moderately forked, longer than all other fins, and with i,7,7,i* (5); i,6,8,i (6) or i,6,7,i (5) principal rays; upper and lower lobes subequal, lower slightly deeper than upper, tip of upper lobe more pointed than lower. Procurrent rays symmetrical, extending anteriorly only to hypural margin.

Distance between pectoral-fin and pelvic-fin origins equal to distance between pelvic fin and posterior most base of anal fin; interdorsal distance equal to post-adipose distance; pectoral spine equal to snout length, length of supraoccipital spine equals interorbital width.

Coloration in preservative. In 70% alcohol: Dorsolateral surface of head and body brown, darker on occipital region. Head and body with minute brown to dark-brown spots scattered throughout except creamy ventral region between snout tip and pelvic-fin origin. Two prominent creamy bands across body: one situated between dorsal and adipose fins and another on caudal peduncle, former band twice as broad as latter at mid-dorsal. A single pair of creamy spots on body just below dorsal-fin origin except in one individual. One pair of small oval creamy patches on upper and lower bases of first procurrent ray, upper patch smaller than lower. Dorsal fin brown with hyaline distal margin. Adipose fin brown, anterior margin with small pale patch at middle, sometimes near base, posterior margin hyaline. Caudal fin with brown base extending up to median rays, with a pale to hyaline narrow band in middle of each lobe, separated by narrow median brown rays. Tips of upper and lower lobes hyaline, upper one smaller than lower. Pectoral, pelvic and anal fins with brown bases and transverse subdistal bands. Pelvic fin with a very narrow subdistal streak, sometimes absent. Nasal barbel overall brown. Maxillary and outer mandibular barbels creamy ventrally, light brown dorsally, annulated with brown rings. Inner mandibular barbel creamy.

Distribution and habitat. Known from the Jiya stream ( Fig. 7 ), near Bolik village in Lower Dibang Valley District, Arunachal Pradesh, India ( Fig. 8 ). The Jiya stream is a small tributary of the Kundil stream that flows into the Lohit River above juncture of the Dibang and Lohit Rivers north of the Dibru-Saikhowa sanctuary, near the Assamese town of Sadiya. The stream-water was clear, moderately flowing adjacent to the main road en route to the Shantipur checkgate. Both species ( Pseudolaguvia magna and P. j i y a en s i s) occur syntopically and were captured along with species of Psilorhynchus , Barilius , and Danio from the same collection locality in a microhabitat consisting of small to medium-sized stones, pebbles, cobbles with light green algae, and deposits of sand particles near banks. In spite of continuous sampling for about 3 hours at the collection site, no species of Glyptothorax were obtained.

Etymology. Pseudolaguvia jiyaensis is named for the “Jiya” stream; an adjective.

Figures

FIGURE 1. Pseudolaguvia magna, ZSI / V / APRC / P- 947, holotype, 46.1 mm SL; dorsal, lateral and ventral views.

FIGURE 5. Pseudolaguvia jiyaensis, ZSI / V / APRC / P- 1034, holotype, 29.9 mm SL; dorsal, lateral and ventral views.

FIGURE 6. Thoracic adhesive apparatus of Pseudolaguvia jiyaensis, ZSI / V / APRC / P- 1035, paratype, 29.6 mm SL.

FIGURE 7. Type locality of Pseudolaguvia magna and P. jiyaensis: Jiya stream, Arunachal Pradesh, India.

FIGURE 8. Map of Arunachal Pradesh and Lower Dibang Valley District showing the type locality of Pseudolaguvia magna and P. jiyaensis, indicated by a red circle.

Tables

TABLE 2. Morphometric data for Pseudolaguvia jiyaensis (n = 16): ZSI / V / APRC / P- 1034 (holotype), ZSI / V / APRC / P- 1035 (15 paratypes).

	Holotype	Range	Mean±SD
Standard length (mm)	29.9	25.6–31.2	29.2+1.5
%SL
Predorsal length	41.5	40.6–45.5	43.1+1.3
Preanal length	70.4	66.8–73.6	70.4+1.8
Prepelvic length	52.2	49.6–54.9	52.1+1.4
Prepectoral length	26.9	24.2–27.7	26.3+1.0
Length of dorsal-fin base	13.8	13.4–16.4	14.2+0.8
Dorsal-fin spine length	14.6	11.9–15.0	14.1+0.9
Length of anal-fin base	15.2	11.3–15.2	13.3+1.3
Pelvic-fin length	14.8	12.9–16.1	15.0+0.7
Pectoral-fin length	24.7	22.6–26.0	24.3+1.1
Pectoral-fin spine length	18.1	16.6–19.8	18.1+1.0
Caudal-fin length	26.1	22.3–29.7	25.9+1.6
Length of adipose-fin base	17.7	13.8–18.0	15.6+1.6
Dorsal to adipose distance	15.4	14.4–17.0	15.7+0.7
Post-adipose distance	15.5	15.5–17.4	16.4+0.8
Caudal peduncle length	17.9	16.0–20.7	18.2+1.1
Caudal peduncle depth	8.9	8.4–10.4	9.3+0.5
Body depth at anus	15.9	14.8–18.4	16.0+0.9
Head length	30.5	30.3–33.3	31.8+1.0
Head width at pectoral fin origin	22.7	21.9–25.2	23.1+0.9
Head depth just posterior to eye	11.8	10.2–15.5	12.5+1.3
%HL
Snout length	51	47–55	50.0+2.6
Interorbital width	32	26–32	29.9+2.0
Eye diameter	12	11–18	13.7+2.2
Nasal barbel length	14	13–23	16.5+3.2
Maxillary barbel length	67	54–68	62.8+4.7
Outer mandibular barbel length	50	46–61	54.2+5.3
Inner mandibular barbel length	33	28–38	33.9+3.1