Amblypharyngodon grandisquamis Jordan & Starks, 1917

Sudasinghe, Hiranya, Pethiyagoda, Rohan, Maduwage, Kalana & Madhava Meegaskumbura,, 2019, The identity of the Sri Lankan Amblypharyngodon (Teleostei, Cyprinidae), ZooKeys 820, pp. 25-49 : 31-35

Amblypharyngodon grandisquamis Jordan & Starks, 1917 Figure 4

Amblypharyngodon melettinus , Non-Valenciennes, 1844 (from Sri Lanka): Günther 1868: 202; Day 1878: 555; Day 1889: 292; Duncker 1912: 265; Deraniyagala 1952: 45; Senanayake 1980: 167; Pethiyagoda 1991: 25; Pethiyagoda 2006; MOE 2012; De Silva et al. 2015.

Material examined (all from Sri Lanka).

SU 22868, 8 paratypes, 56.4-65.4 mm SL, river at Colombo (presumably the Kelani, which is the only river in the vicinity of the city); WHT 30275, 6, 65.0-76.4 mm SL, Bolgoda River basin, Bellanwila-Attidiya; WHT 64, 3, 45.4-47.5 mm SL, Kalu River basin, Ingiriya, Dombagaskanda; WHT 22, 2, 37.2-38.7 mm SL, Kalu River basin, Walandure, Kuruwita; WHT 225, 2, 30.2-34.3 mm SL, Kalu River basin, Ekneligoda, Kuruwita; WHT 30790, 3, 49.3-52.8 mm SL, Kelani River basin, Deraniyagala; WHT 32, 3, 49.6-60.1 mm SL, Attanagalu Oya basin, Weliweriya; WHT 30260, 58.2 mm SL, Nilwala River basin, Godapitiya, Akuressa; WHT 30167, 3, 54.2-74.7 mm SL, Malwathu Oya basin, Anuradhapura; DZ 3193, 7, 57.2-74.0 mm SL, Mahaweli River basin, Polonnaruwa; DZ 3564, 2, 57.2-62.3 mm SL, Mahaweli River basin, Badulu Oya, Kandeketiya; WHT 1694, 3, 42.7 -45.1 mm SL, Mahaweli River basin, Wasgamuwa; WHT 45, 4, 54.6-71.9 mm SL, Mi Oya basin, Puttlam; WHT 1810, 4, 40.8-52.4 mm SL, Kirindi Oya basin, Weerawila; WHT 1851, 41.2 mm SL, Gal Oya basin, Rathugala near Bibile. Cleared and stained: WHT 11075, 64.2 mm SL, Bolgoda River basin, Bellanwila-Attidiya; WHT 11046, 54.2 mm SL, Mi Oya basin, Puttlam; WHT 11081, 45.1 mm SL, Mi Oya basin, Puttlam; WHT 11052, 45.9 mm SL, Kelani River basin, Deraniyagala; WHT 11070, 40.0 mm SL, Kelani River basin, Deraniyagala. Other material (identified for distribution data, but not measured): WHT 30789, Mahaweli River basin, Wasgamuwa; DZ 3434, Mahaweli River basin, Naula; DZ 1504, Mahaweli River basin, Ulhitiya; WHT 30263, Deduru Oya basin, Wewagama, Kuliyapitiya; WHT 30679, Deduru Oya basin; WHT 2158, Kirindi Oya basin, Tissamaharama; DZ 4423, Kirindi Oya basin, Lunugamwehera; WHT 30723, Heda Oya, Lahugala; WHT 30310, Kala Oya basin, Eluwankulam; WHT 30167, Malwathu Oya basin, Anuradhapura; DZ 4042, Attanagalu Oya basin, Yakkala; DZ 3577, Mi Oya basin, Galgamuwa; DZ 3292, Kalu River basin, Remuna.

Diagnosis.

Amblypharyngodon grandisquamis is distinguished from A. melettinus by having a deeper body (26.9-31.2% SL in A. grandisquamis , vs. 22.9-26.3 in A. melettinus ); fewer pored lateral-line scales (8-16 (25), 19 (1), vs. 15(1), 17-21 (13) in A. melettinus : Figure 3A); more caudal vertebrae (18-19 (5), vs. 17 (2) in A. melettinus ); 2-4 minute foramina (absent in A. melettinus ) in addition to a large foramen on the base of the lateral arm of the fifth ceratobranchial; and absence of a minute foramen at the base of the medial arm of the fifth ceratobranchial (present in A. melettinus ). It differs from A. microlepis by having fewer scales in the lateral series (42-56 vs. 55-65 in A. microlepis ) and a greater body depth (26.9-31.2% SL vs. 24.3-26.3 in A. microlepis ); from A. mola by a lesser dorsal-fin height (21.1-27.6% SL vs. 27.8-29.2 in A. mola ), shorter eye diameter (22.7-30.5% HL vs. 31.3-36.6 in A. mola ), fewer scales in the lateral series (42-56 vs. 69-73 in A. mola : Figure 3B), fewer circumpeduncular scales (20-24 vs. 27-31 in A. mola : Figure 3C), and fewer scale rows between the origins of the dorsal and pelvic fins (14-17 vs. 23-25 in A. mola : Figure 3D); from A. chulabhornae by having more pored lateral-line scales (8-16 (25) or 19 (1) vs. 6-7 in A. chulabhornae ) and more vertebrae (33-34 (5) vs. 31-32 in A. chulabhornae ); and from A. atkinsonii by having fewer scales in the lateral series (42-56 vs. 55-61 in A. atkinsonii ), a lesser body depth (26.9-31.2% SL, vs. 40.5 in A. atkinsonii ), and fewer scale rows between the origins of the dorsal and pelvic fins (14-17 vs. 21 in A. atkinsonii ).

Description.

For general appearance, see Figure 4; morphometric data are provided in Table 5. Head and body oblong, slightly compressed. Head wider than body. Body depth greatest at dorsal-fin origin. Snout short, subequal to eye diameter, dorsally rounded, laterally subtriangular. Mouth terminal; symphysial knob present, small, elongated, fitting into shallow groove on inner margin of upper jaw with mouth closed.

Lateral line incomplete, with 8 (1), 9 (2), 10 (4), 11 (4), 12 (6), 13 (5), 15 (1), 16 (2) or 19 (1) pored scales, 42 (1), 44 (1), 45 (4), 46 (3), 47 (4), 48 (4), 49 (2), 50 (1), 51 (1), 52 (2), 53 (2) or 56 (1) scales in lateral series plus 2-4 scales on base of caudal fin. Predorsal scales 27 (2), 28 (3), 29 (2), 30 (2) or 32 (1). Prepelvic scales 25 (1), 26 (1), 27 (1), 28 (1), 29 (1), 30 (2), 31 (1), 33 (1) or 34 (1). Lateral scale rows between origins of dorsal and pelvic fins ½8+1+5½ (1), ½8 +1+6 (1), ½9+1+4½ (2), ½9+1+5½ (8), ½9 +1+6 (1), ½9+1+6½ (2), ½10+1+4½ (1), ½10 +1+5 (1), ½10+1+5½ (4), or ½10+1+6½ (5). Circumpeduncular scales 20 (2), 21 (7), 22 (10), 23 (5) or 24 (2).

Dorsal fin with two unbranched and seven branched rays, its origin just posterior to vertical through pelvic-fin origin, its distal margin straight. Anal fin with three unbranched and five branched rays, its origin slightly posterior to vertical through origin of dorsal fin, its distal margin slightly concave. Pectoral fin with a single unbranched and 11 (1), 12 (10), 13 (2), or 14 (1) branched rays, its origin anterior to posteriormost point of opercular opening, not reaching pelvic-fin origin when adpressed. Pectoral-fin axillary lobe rudimentary. Pelvic fin with one unbranched and 7 (3) or 8 (13) branched rays, its origin slightly closer to anal-fin origin than to origin of pectoral fin, its tip not reaching anal-fin origin when adpressed. Pelvic ‘axillary’ scale present. Caudal fin with 9 + 8 (14) branched rays, forked, lobes rounded distally, upper and lower lobes subequal.

Vertebrae 15 + 18 = 33 (1), 15 + 19 = 34 (4). Pharyngeal teeth 5 + 2 + 1 (4), 5 + 3 + 1 (1) (Figure 5 A–C). Fifth ceratobranchial with 2-4 minute foramina in addition to a large foramen at base of lateral arm; no foramen at base of medial arm (Figure 5 A–C).

Coloration.

In 70% alcohol (Figure 4B), head and body silvery brown, darker dorsally, becoming lighter laterally, off-white ventrally. Head darker than body. Dusky-brown stripe 1 –1½ scales wide on side of body, from immediately behind operculum, extending to caudal fin base, broader at middle, scales above it with prominent melanophores throughout, scales below it with scattered melanophores on margins, disappearing ventrally. Fins hyaline. Dorsal and caudal fins with scattered melanophores, more prominent on caudal fin.

In life (Figure 4A), head and body silvery grey to iridescent gold, lighter laterally. Scattered melanophores on side of body. A faint yellowish stripe extending from behind operculum to caudal fin base. Caudal fin yellowish, other fins mostly hyaline.

Habitat, distribution, and natural history.

Amblypharyngodon grandisquamis occurs in lotic habitats such as rivers and canals as well as in lentic habitats such as reservoirs and marshes. The species is recorded primarily from the lowland floodplain of Sri Lanka, in both the dry and the wet zones of the island (annual precipitation less than, and greater than, 2,000 mm, respectively), though much more frequently encountered in the dry zone (Figure 6). The highest elevation from which we recorded A. grandisquamis was at ca 460 m a.s.l., in the Samanala reservoir on the Walawe River basin. It is a slow-swimming fish, usually encountered in large groups close to the surface. With the onset of the rains, adults are observed in rice paddies, probably migrating there to spawn. The relative abundance of A. grandisquamis , at least in the wet zone, appears to be seasonal, with more adults usually observed during the rainy season.