Pseudolaguvia vespa, Praveenraj & Vijayakrishnan & Lima & Gurumayum, 2021

Praveenraj, Jayasimhan, Vijayakrishnan, Balaji, Lima, Akum & Gurumayum, Shantabala Devi, 2021, A new sisorid catfish of the genus Pseudolaguvia (Teleostei: Sisoridae) from Nagaland, north-eastern India, Zootaxa 5082 (1), pp. 77-86 : 78-82

Pseudolaguvia vespa , new species

( Figs. 1 , 2a , 3b , 4 )

Holotype. ZSI/ APRC /P-1882, 30.6 mm SL; India, Nagaland, Mokokchung district, Tsücha River, Khar Village ; 26°27.59’ N, 94°29.63’ E; 294.4m asl.; Lima and team, 21 April 2021.

Paratype. ZSI/ APRC /P-1883, 8 ex., 28.6–31.5 mm SL ; CIARI /FF-79, 1 ex., 29.5 mm SL, cleared and stained. Collection data same as holotype .

Diagnosis. Pseudolaguvia vespa differs from all its congeners except P. ribeiroi , P. spicula , P. shawi , P. nubila and P. jiyaensis by the following combination of characters: a shorter dorsal-fin spine (12.3–16.8% SL vs. 17.3– 29.0), a deeper caudal peduncle (9.0–10.5% SL vs. 6.5–9.2), deeper body (body depth at anus 15.6–17.7% SL vs. 11.0–15.2), shorter caudal fin (20.7–24.5% SL vs. 27.8–33.2), shorter pectoral fin (20.1–24.1% SL vs. 24.1–36.6), shorter interorbital distance (22.7–28.1% SL vs. 28.2–36.0). Pseudolaguvia vespa differs from P. ribeiroi in having a smooth (vs. serrated) anterior margin of the dorsal-fin spine, a deeper body (depth at anus 15.6–17.7% SL vs. 13.6–14.8) and a longer pectoral fin (20.1–24.17% SL vs. 13.6–15.4). Pseudolaguvia vespa is readily distinguished from P. shawi and P. nubila in having a greater pre-anal length (71.3–74.2% SL vs. 65.8–69.7) and more total vertebrae (33 vs. 31–32). It can further be differentiated from P. shawi in having the pectoral fin not reaching (vs. reaching) anterior origin of pelvic fin when adpressed and from P. nubila in having a shorter anal-fin base (12.1–14.6 % SL vs. 15.6–19.7). Pseudolaguvia vespa can also be differentiated from P. spicula in having a longer pectoral-fin spine (18.2–21.0% SL vs. 15.7–17.4), contrasting (vs. indistinct) banding on the body and a shorter interorbital distance (22.7–28.1% HL vs. 28.2–32.1).

Pseudolaguvia vespa appears most similar to P. jiyaensis in colouration but can be readily distinguished from this species by the following characters: thoracic adhesive apparatus extending to midway between base of last pectoral-fin ray and pelvic-fin origin (vs. thoracic adhesive apparatus almost reaching pelvic-fin origin) ( Fig. 2 ), a shorter head (25.9–29.2% SL vs. 30.3–33.3), posterior margin of the dorsal-fin spine with 3 serrae (vs. smooth), the region between lower lip and thoracic adhesive apparatus sparsely papillated (vs. densely papillated) ( Fig. 3 ).

Additional characters distinguishing it from other congeners are provided in the discussion.

Description. Morphometry data presented in table. 1. Head dorsoventrally depressed, body moderately compressed. Dorsal profile rising gently from tip of snout to origin of dorsal fin, then sloping gently ventrally to end of caudal peduncle. Ventral profile slightly concave from tip of snout to pelvic fin origin, then sloping gently dorsally to end of caudal peduncle. Supraoccipital spine nearly reaching nuchal shield. Snout slightly truncate when viewed dorsally. Weberian lamina well developed, slightly longer than supraoccipital spine, extending parallel to either side of spine. Eyes ovoid, horizontal axis longest and placed dorsally and entirely on posterior half of head. Gill slit narrow, extending from posttemporal to isthmus. Body with numerous tubercles except on thoracic adhesive apparatus and ray portion of the fins. Mouth subterminal, lips fleshy and papillated, region between lower lip and thoracic adhesive apparatus sparsely papillated, upper jaw projecting over lower jaw. Barbels in four pairs, upper lip continuing into maxillary barbel, with broad skin flap at base, extending almost close to base of pectoral-fin spine. Lateral mandibular barbel with moderately broad skin flap on dorsal margin, extending till 8 th branchiostegal ray; medial mandibular barbel broad and shorter, reaching to vertical through middle of eye orbit; nasal barbel very short and broad, extending to one-third distance between its base and anterior orbital margin. Thoracic adhesive apparatus moderately elliptical with a prominent central median depression, anterior portion moderately wide, narrow posteriorly, extending to midway between base of last pectoral-fin ray and pelvic-fin origin.

Dorsal fin located about two-fifths of standard length along body, with 5, i (1), 6, i*(2) or 6 (7) rays and straight margin. Dorsal spine straight, osseous and pointed, compressed laterally. Anterior margin of spine smooth and posterior margin with 3 serrae distally. Adipose fin short, anterior margin straight, posterior margin straight to slightly convex with incised posterior end, its origin slightly anterior to pelvic fin origin. Pectoral fin with strong, dorsoventrally depressed, pointed spine and 7*(2) or 8 (8) rays. Anterior margin of spine with 7* (2), 8 (2), 9 (6) moderate serrations, distally directed, becoming granular towards base; posterior margin with 5 (1) or 6* (9) 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 girdle with prominent postcoracoid processes, hidden beneath skin, extending to midway between its base and pelvic-fin origin. Lateral line complete and midlateral. Pelvic fin with i, 4, i (2) or i, 5, i* (8) rays, anterior margin slightly convex, tip of adpressed fin extending beyond anus, but never reaching anal-fin origin. Anal fin with iv, 5, i* (5), iv, 6, i (4) or iv, or iv, 7, i (1) rays, its posterior margin slightly convex posterior margin straight. Caudal fin moderately forked with i, 14, i (10) principal rays; upper and lower lobes subequal, lower deeper in width than upper lobe, tip of upper lobe more pointed than lower. Basal margin of caudal fin rays with tubercules. Procurrent rays symmetrical, extending anteriorly only to hypural margin. Vertebrae 17+16=33 (1).

Colouration. In life ( Fig. 4 ). Dorsolateral surface of head and body brown, occipital region dark-brown to black. Head and body pale-brown to chest nut coloured with numerous minute, brown to dark-brown spots scattered throughout, except ventral region between snout tip and pelvic-fin origin with few spots. The space between the ridges of thoracic adhesive apparatus also with minute pigmentation. Two prominent irregular chrome-yellow bands across body: one situated between dorsal and adipose fins and the other on caudal peduncle, former band twice as broad as latter at mid-dorsal. A pair of chrome-yellow spots on each side body just below dorsal-fin origin. One pair of large irregular chrome-yellow patches on upper and lower bases of first procurrent ray, upper patch smaller than lower. Dorsal fin dark-brown with chrome yellow distal margin. Adipose fin brown, anterior and posterior margin with small pale-yellow patch. Caudal fin with dark-brown base extending up to median rays, and an irregular subdistal brown band parallel to posterior edge of fin. Tips of upper and lower lobes hyaline, upper one smaller than lower. Pectoral, pelvic and anal fin translucently pale-yellow with brown bases and dark-brown transverse subdistal bands; the bands on pelvic fin very narrow. Nasal barbel brown with numerous black spots. Maxillary and outer mandibular barbels pale-yellow annulated with brown rings. Inner mandibular barbel creamy-white. In preservative ( Fig. 1 ): colouration similar to live condition except the chrome-yellow to pale-yellow colouration on fins appears hyaline.

Distribution and habitat. Pseudolaguvia vespa is presently known only from the type locality in the Tsücha River, a tributary of the Milak River, a south bank tributary of the Brahmaputra River, Khar Village, Mokokchung district, Nagaland. Co-occurring species included Pterocryptis indicus , Balitora sp. , Garra sp. and Amblyceps apangi .

Etymology. The specific name vespa is derived from the Latin, meaning wasp, in reference to the alternating chrome-yellow and brown stripes on the body resembling a wasp. Used as an adjective.

Figures

FIGURE 1. Pseudolaguvia vespa, holotype, ZSI/APRC/P-1882, 30.6 mm SL; lateral, dorsal and ventral views.

FIGURE 2. Ventral view showing details of thoracic adhesive apparatus in: a. Pseudolaguvia vespa, ZSI/APRC/P-1882, holotype, 30.6 mm SL; b. P. jiyaensis, CIARI/FF-76, 26.9 mm SL. Black line indicates posterior most extent of thoracic adhesive apparatus. Figure not to scale.

FIGURE 3. Ventral view showing details of papillation in: a. Pseudolaguvia vespa, ZSI/APRC/P-1882, holotype, 30.6 mm SL; b. P. jiyaensis, CIARI/FF-76, 26.9 mm SL. Yellow line indicates the region between lower lip and thoracic adhesive apparatus. Figure not to scale.

FIGURE 4. Pseudolaguvia vespa, ZSI/APRC/P-1882, holotype, 30.6 mm SL, showing fresh colouration.