Pseudolaguvia spicula, Ng, Heok Hee, 2010

Ng, Heok Hee, 2010, Pseudolaguvia spicula, a new sisorid catfish (Teleostei: Sisoridae) from Bangladesh and northeastern India, Zootaxa 2558, pp. 61-68 : 62-65

Pseudolaguvia spicula sp. nov.

( Fig. 1 )

(?) Pseudolaguvia shawi (non Hora)— Kar & Sen, 2007: 2603 Pseudolaguvia cf. ferruginea — Ng, 2009: 286, Fig. 9.

Type material. Holotype: PUCMF 1032, 31.1 mm SL; India: Mizoram, Bawrai River, a tributary of Langkaih River in the vicinity of Zawlnuam, 24°7'37.2"N 92°20'42.0"E; Lalramliana, 7 January 2010.

Paratypes: PUCMF 1033 (5), 26.2–30.2; data as for holotype. PUCMF 1034 (2), 25.5–26.5 mm SL; UMMZ 248864 (2), 25.7–26.5 mm SL; India: Mizoram, Sihthiang River, a tributary of the Teirei River in the vicinity of Sihthiang, 24°4'12.0"N 92°27'25.2"E; Lalramliana, 2 February 2010. PUCMF 1035 (6), 24.0– 29.1 mm SL; India: Mizoram, Teirei River in the vicinity of Saikhawthlir, 24°8'45.6"N 92°27'50.4"E; Lalramliana, 6 January 2010. PUCMF 1036 (13), 23.5–30.2 mm SL; India: Mizoram, Tuirial River in the vicinity of Melriat, 23°38'31.0"N 92°43'23.0"E; Lalramliana, 14 January 2010. UMMZ 248806 (1), 25.2 mm SL; Bangladesh: Rangapani Khal, 6.4 km NNW of Jaintapur on Sylhet-Shillong highway, 25°10'N 92°6'E; W. J. Rainboth et al., 19 February 1978.

Diagnosis. Pseudolaguvia spicula differs from congeners except for P. inornata , P. kapuri , P. tenebricosa , P. tuberculata and P. v i rg u l a t a in having a deeper caudal peduncle (7.9–9.6% SL vs. 5.0–8.1). It is distinguished from P. inornata in having shorter dorsal- (11.6–14.3% SL vs. 18.6–21.7) and pectoral-fin spines (15.7–17.4% SL vs. 20.4–23.3) and indistinct, pale vertical bands on the body (vs. bands absent), and from P. kapuri in having a shorter dorsal-fin spine (11.6–14.3% SL vs. 14.0–15.5), shorter adipose-fin base (14.7–17.1% SL vs. 17.1–18.9), and narrower head (19.2–22.6% SL vs. 23.4–24.0). Pseudolaguvia spicula differs from P. tenebricosa in having shorter dorsal- (11.6–14.3% SL vs. 15.8–17.3) and pectoral-fin spines (15.7–17.4% SL vs. 18.7–20.4) and a shorter caudal fin (24.2–27.5% SL vs. 28.5–31.2), from P. tuberculata in having a shorter snout (48.6–51.9% HL vs. 52.1–55.5), larger eye (10.6–13.9% HL vs. 8.8–10.4) and shorter pectoral-fin spine (15.7–17.4% SL vs. 18.3–20.1), and from P. virgulata in having shorter dorsal- (11.6–14.3% SL vs. 21.5–24.0) and pectoral-fin (15.7–17.4% SL vs. 28.5–29.1) spines and caudal peduncle (15.4–17.9% SL vs. 18.2–20.2), a smooth (vs. serrated) anterior edge of the dorsal-fin spine, the presence of pale vertical bands (vs. pale longitudinal stripes) on the flanks and the absence (vs. presence) of a pale yshaped marking on the dorsal surface of the head and supraoccipital process.

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 not reaching nuchal shield. Weberian lamina well developed, approximately same length as supraoccipital spine, extending parallel to either side of spine. Eye ovoid, its 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 of moderate length and depth. 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 14+16=30 (1), 15+15=30* (4), 16+14=30 (3), 15+16=31 (3), 16+15=31 (8), 15+17=32 (1) or 16+16=32 (10). Thoracic adhesive apparatus consisting of longitudinal, unculiferous ridges arranged in elliptical field and with prominent central median depression. Adhesive apparatus extending to midway of distance 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, broad, extending to midway between its base and anterior orbital margin. Maxillary barbel slender, with broad skin flap at base, extending just beyond base of pectoralfin spine. Outer mandibular barbel with broad skin flap on dorsal margin, extending to base of pectoral-fin spine; inner mandibular barbel broad, shorter, reaching to vertical through middle of orbit.

Dorsal fin located about two-fifths along body; with 5 (2) or 5, i* (28) rays. Dorsal-fin spine flattened, straight, robust; spine extending to vertical slightly posterior to base of pelvic fin. Anterior margin of spine smooth; posterior margin with 3–5 larger, indistinct serrations.

Pectoral fin with stout, blade-like spine, sharply pointed at tip, with 6,i (10), 6,ii* (13) or 7,i (7) rays. Anterior spine margin with 9–15 small, distinct serrae. Posterior spine margin with 5–7 large, distinct serrae. Anterior and posterior pectoral-fin margin straight. Coracoid with moderately long posterior process, extending along proximal two-thirds of pectoral spine. Pelvic-fin origin at vertical through middle of dorsalfin base. Pelvic fin with i, 5 (30) rays, its margin straight; tip of adpressed fin not reaching anal-fin origin. Adipose fin short, its posterior end deeply incised; fin located above anal-fin base. Anal fin with iii,5,i (15), iii,6 (1), iii,5,ii (2), iv,5,i* (11) or iv,5,ii (1) rays, its anterior and posterior margins straight. Caudal peduncle moderately deep. Caudal fin deeply forked, with i,7,7,i (30) 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. Body with two irregular cream bands: first band on sides of body between dorsal and adipose fins, second band on caudal peduncle. Bands with indistinct margins. Almost all of dorsal fin brown, with very thin, irregular hyaline distal margin. Anal fin with brown base and irregular subdistal band; brown band at base and subdistal band partially coalescent in some individuals, leading to appearance of hyaline spot in middle of first two or three anal-fin rays. Pelvic fin hyaline with transverse brown bands at base and along middle third of fin. Pectoral fin with brown base and transverse brown subdistal band. Caudal fin predominantly brown, with hyaline tips and hyaline patches on middle of median principal rays. Adipose fin brown at base, paler along dorsal and posterior parts. Nasal barbel brown dorsally, cream ventrally; maxillary and outer mandibular barbels cream, annulated with brown bands; inner mandibular barbel cream. Coloration in life similar, except with a strong yellow hue.

Distribution and habitat. This species is known from the Surma-Meghna River system (one of the three river systems that forms the Ganges Delta), being found in the upper (Barak River drainage in Mizoram, India) and the middle (Meghna River drainage in northeastern Bangladesh) portions of the system ( Fig. 2 ). This species was collected from shallow streams with a moderate to strong current and a substrate of sand, pebble and rocks. Water temperature in the streams ranged from 19–23°C. The following species of fishes were associated with P. s p i c u l a at its type locality: Psilorhynchus sucatio (Psilorhynchidae) , Glyptothorax botius (Sisoridae) , G. telchitta (Sisoridae) and Pseudolaguvia virgulata (Sisoridae) .

Etymology. The specific epithet is the diminutive form of the Latin noun spica, meaning a point or a spike. This name is used in reference to the relatively short dorsal- and pectoral-fin spines of this species when compared to many congeners. It is applied as a noun in apposition.

Figures

FIGURE 1. Pseudolaguvia spicula, PUCMF 1032, holotype, 31.1 mm SL; dorsal, lateral and ventral views.

FIGURE 2. Map showing collection localities of Pseudolaguvia spicula. Each circle may indicate more than one locality.

Tables

TABLE 1. Biometric data for Pseudolaguvia spicula (n = 30).

	Holotype	Range	Mean±SD
%SL
Predorsal length	40.2	37.4–40.4	38.9±1.08
Preanal length	66.9	66.0–69.9	68.0±1.35
Prepelvic length	49.5	46.7–50.7	48.5±1.33
Prepectoral length	22.8	21.0–25.0	23.0±1.41
Length of dorsal-fin base	13.5	13.2–15.9	14.3±1.01
Dorsal-fin spine length	12.5	11.6–14.3	13.1±0.79
Length of anal-fin base	17.7	14.3–17.7	16.0±1.08
Pelvic-fin length	15.8	14.6–17.1	15.8±0.97
Pectoral-fin length	22.8	19.9–23.0	21.9±1.04
Pectoral-fin spine length	17.4	15.7–17.4	16.7±0.66
Caudal-fin length	25.7	24.2–27.5	25.9±1.10
Length of adipose-fin base	16.4	14.7–17.1	15.6±0.84
Dorsal to adipose distance	16.4	13.9–17.9	15.9±1.37
Post-adipose distance	13.2	13.2–18.1	15.8±1.33
Caudal peduncle length	15.4	15.4–17.9	16.5±0.85
Caudal peduncle depth	8.7	7.9–9.6	8.5±0.47
Body depth at anus	14.4	12.8–16.8	14.4±1.09
Head length	26.0	26.0–28.8	27.7±0.84
Head width	21.5	19.2–22.6	20.6±1.12
Head depth	16.1	15.6–19.1	17.3±1.24
%HL
Snout length	50.6	48.6–51.9	50.3±1.28
Interorbital distance	29.6	28.2–32.1	30.4±1.33
Eye diameter	12.3	10.6–13.9	12.2±1.06
Nasal barbel length	16.0	14.6–23.3	17.8±2.84
Maxillary barbel length	80.2	61.1–85.4	76.7±8.71
Inner mandibular barbel length	49.4	27.4–51.4	40.3±7.59
Outer mandibular barbel length	64.2	39.3–72.6	58.3±11.28