Glyptothorax platypogonides (Bleeker 1855)

Ng, Heok Hee & Kottelat, Maurice, 2016, The Glyptothorax of Sundaland: a revisionary study (Teleostei: Sisoridae), Zootaxa 4188 (1), pp. 1-92: 61-63

publication ID

http://doi.org/10.11646/zootaxa.4188.1.1

publication LSID

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scientific name

Glyptothorax platypogonides (Bleeker 1855)
status

 

Glyptothorax platypogonides (Bleeker 1855) 

( Fig. 31View FIGURE 31)

Pimelodus platypogonides Bleeker, 1855a: 260  , 272 (type locality: Lahat, Sumatra).

Glyptosternon platypogonides  — Bleeker, 1858c: 219; 1860a: 47.

Glyptothorax platypogonoides  — Hubrecht, 1887: 11; Fowler, 1915: 220; Roberts, 1989: 136 (in part).

Glyptothorax platypogonides  — Fowler, 1904: 500; Kottelat et al., 1993: 77 (not pl. 37 which is G. schmidti  ); Tan & Ng, 2000: 292; Jiang et al., 2011: 280.

Glyptosternum platypogonoides  —Weber & de Beaufort, 1913: 267.

Glyptothorax lampris  (non Fowler, 1934)— Jiang et al., 2011: 280.

Material examined. SUMATRA: RMNHAbout RMNH 6912View Materials (4 syntypes), 53.6–67.1 mm SL  ; RMNH 15289 (3 syntypes), 65.6– 73.5 mm SL; Sumatera Selatan: Lahat. ANSPAbout ANSP 27285View Materials (1), 78.0 mm SL  ; Sumatera Barat: Kabupaten Tanah Datar , Batusangkar. UMMZAbout UMMZ 243329View Materials (1), 59.6 mm SL  ; Sumatera Barat: market at Kiliranjao. UMMZAbout UMMZ 243339View Materials (3), 40.4– 71.7 mm SL  ; ZRCAbout ZRC 41588View Materials (15), 43.9–78.2 mm SL, Sumatera Barat: market at Sungaidareh   . ZRC 53525 (4), 38.5– 52.8 mm SL; CMK 20532View Materials (4), 36.0– 51.1 mm SL; Sumatera Selatan: market in Lahat, Lematang (Musi) drainage, 3°48'S 103°32'EGoogleMaps  . UF 166621View Materials (9), 40.5–56.4 mm SL; Sumatera Selatan: Air Lematang , 3°45'29.22"S 103°39'22.14"EGoogleMaps  . UF 166622View Materials (1), 50.0 mm SL; Sumatera Selatan: Air Kikim Kecil , 3°45'49.92"S 103°27'34.08"EGoogleMaps  . UF 166626View Materials (1), 52.4 mm SL; Lampung: Way Besai , 4°45'26.88"S 104°33'19.56"E.GoogleMaps 

MALAY PENINSULA: UMMZ 245600 (1 alc., 1 c&s), 66.2–67.8 mm SL; Thailand: Surat Thani, Tapi River drainage; Khlong Sok at Phanom. ZRCAbout ZRC 53482View Materials (2), 37.5–39.3 mm SL  ; Malaysia: Pahang, Sungai Tembeling near Jeram Pai  , Pahang River drainage, 4°05'N 102°20'E.GoogleMaps 

Diagnosis. Glyptothorax platypogonides  is very similar to G. exodon  in terms of overall shape (a relatively slender body and caudal peduncle) and in sharing a mottled color pattern, but can be distinguished from it in having the premaxillary toothband two-thirds (vs. almost entirely) exposed when the mouth is closed. It differs from the other Sundaic congeners in having a unique combination of the following characters: anteromedial striae in the thoracic adhesive apparatus absent; eye diameter 11–14% HL; head length 25.2–26.8% SL; head width 17.0– 20.5% SL; predorsal length 36.5–39.1% SL; pectoral-fin spine length 17.8–22.7% SL; dorsal-fin spine length 15.6–19.3% SL; smooth posterior margin of dorsal-fin spine; margin of dorsal fin concave; dorsal-to-adipose distance 20.2–23.6% SL; body depth at anus 12.1–14.8% SL; adipose-fin base length 10.7–13.7% SL; straight dorsoposterior margin of adipose fin; caudal peduncle depth 6.5–7.9% SL; post-adipose distance 17.6–21.5% SL; caudal fin without prominent dark longitudinal stripes running through each lobe; and mottled body with neither prominent pale midlateral stripe nor dark vertical bands.

Description. Morphometric data in Table 12. Head depressed; body slender, subcylindrical. Dorsal profile rising evenly from tip of snout to origin of dorsal fin, then sloping gently ventrally from origin of dorsal fin to end of caudal peduncle. Ventral profile straight to anal-fin base, then sloping gently dorsally from anal-fin base to end of caudal peduncle. Anus and urogenital openings located at vertical through middle of adpressed pelvic fin. Skin tuberculate, with tubercles of even size on sides of body. Lateral line complete and midlateral. Vertebrae 16+18=34 (1), 17+17=34 (8), 16+19=35 (1), 17+18=35 (12), 17+19=36 (4) or 18+18=36 (5).

Head depressed and broad, triangular when viewed laterally. Snout prominent. Anterior and posterior nares large and separated only by base of nasal barbel. Gill opening broad, extending from ventral margin of posttemporal to isthmus. First branchial arch with 2+5 (1), 2+6 (14) or 2+7 (5) rakers. Bony elements of dorsal surface of head covered with thick, tuberculate skin. Eye ovoid, horizontal axis longest; located entirely in dorsal half of head.

Barbels in four pairs. Maxillary barbel long and slender, extending to middle of pectoral-fin base. Nasal barbel slender, extending to midway between its base and anterior orbital margin. Inner mandibular-barbel extending to midway between its base and that of pectoral spine. Outer mandibular barbel extending to two-thirds of distance between its base and that of pectoral spine.

Mouth inferior, premaxillary tooth band partially (approximately two-thirds) exposed when mouth is closed. Oral teeth small and villiform, in irregular rows on all tooth-bearing surfaces. Premaxillary teeth appearing in single broad semilunate band. Dentary teeth in a single crescentic band, consisting of two separate halves tightly bound at midline.

Thoracic adhesive apparatus consisting of keratinized striae in an elliptical field extending from isthmus to just beyond posterior limit of pectoral-fin base ( Fig. 3View FIGURE 3 l). Anteromedial striae absent. Narrow, v-shaped medial pit on posterior half.

Dorsal fin located above anterior third of body, with I,6 (20) rays; fin margin concave; spine short and straight, smooth on anterior and posterior margins. Adipose fin with anterior margin straight or slightly concave and posterior margin straight. Caudal fin strongly forked, with lower lobe slightly longer than upper lobe and i,7,8,i (20) principal rays. Procurrent rays symmetrical and extending only slightly anterior to fin base. Anal-fin base vertically opposite adipose-fin base. Anal fin with straight anterior margin and straight or slightly concave posterior margin; with iv,8 (3), iv,8,i (5), iv,9 (5) or iv,9,i (7) rays. Pelvic-fin origin at vertical through posterior limit of dorsal-fin base. Pelvic fin with slightly convex margin and i,5 (20) rays; tip of adpressed fin not reaching anal-fin origin. Pectoral fin with I,8 (1), I,8,i (18) or I,9 (1) rays; posterior fin margin slightly concave; anterior spine margin smooth, posterior margin with 6–14 serrations.

Coloration. In 70% ethanol: Dorsal and lateral surfaces of head, and body brown to brownish gray, fading to beige on ventral surfaces. A dark, diffuse midlateral stripe running along lateral line; lateral line without such pigmentation in some individuals, causing it to show up as paler stripe within darker stripe. Body often with four long, elliptical pale patches: first above lateral line and spanning region between dorsal and adipose fins, second below lateral line and first spot, third on anterior half of caudal peduncle above lateral line and fourth on anterior half of caudal peduncle below lateral line, with pale patches imparting appearance of dark vertical band on body between adipose and anal fins. Dorsal fin with brown base and broad subdistal triangular brown mark. Pectoral fin hyaline, with brown melanophores forming a diffuse broad, transverse band subdistally. Pelvic fin hyaline, with faint transverse brown band in middle. Anal fin with brown base and brown melanophores forming V-shaped subdistal mark on anterior half of fin; rest of fin hyaline. Adipose fin brown to brownish gray, with hyaline distal margin. Caudal fin brown to brownish gray, tips and posterior margins of lobes hyaline. Maxillary barbel brown to brownish gray dorsally, beige ventrally.

Distribution. Glyptothorax platypogonides  is known from the upper part of river drainages in central and southern Sumatra (from the Batang Hari drainage southwards to the short coastal drainages that drain the southern tip of the island), as well as the Malay Peninsula in rivers on the eastern slope from the Tapi River drainage southwards to the Pahang River drainage ( Fig. 24View FIGURE 24).

Comparisons. There are seven other congeners known from Sumatra: G. amnestus  , G. famelicus  , G. f u s c u s, G. keluk  , G. ketambe  , G. plectilis  and G. schmidti  . Glyptothorax platypogonides  differs from G. amnestus  in lacking (vs. having) anteromedial striae in the thoracic adhesive apparatus and having a larger eye (diameter 11–14% HL vs. 6–10), a more slender body (depth at anus 12.1–14.8% SL vs. 15.3–20.6) and a more slender caudal peduncle (6.5–7.9% SL vs. 9.8–11.2), from G. famelicus  in having a larger eye (diameter 11–14% HL vs. 7–8), a greater predorsal length (36.5–39.1% SL vs. 32.1–35.2) and lacking (vs. having) a prominent pale midlateral stripe on the body, and G. f u s c u s in having a concave (vs. straight) margin of the dorsal fin and a more slender body (depth at anus 12.1–14.8% SL vs. 15.6–20.7). It is distinguished from G. keluk  in having a mottled (vs. uniform) coloration, a larger eye (diameter 11–14% HL vs. 7–11), a straight (vs. convex) dorsoposterior margin of the adipose fin, a shorter adipose-fin base (10.7–13.7% SL vs. 13.6–17.2) and a longer post-adipose distance (17.6–21.5% SL vs. 15.2–16.7), and from G. ketambe  in having a larger eye (diameter 11–14% HL vs. 8–10), a smaller predorsal length (33.3–35.9% SL vs. 36.5–39.1), a longer dorsal-fin spine (15.6–19.3% SL vs. 12.5–14.8), a longer pectoral-fin spine (17.8–22.7% SL vs. 14.3–16.6) and lacking (vs. having) a prominent pale midlateral stripe on the body. Glyptothorax platypogonides  differs from G. plectilis  in lacking (vs. having) anteromedial striae in the thoracic adhesive apparatus and having a more slender body (depth at anus 12.1–14.8% SL vs. 15.3–18.8), a more slender caudal peduncle (depth 6.5–7.9% SL vs. 8.4–10.6) and a longer post-adipose distance (17.6–21.5% SL vs. 14.0– 17.6), and from G. schmidti  in having a larger eye (11–14% HL vs. 5–10), a longer dorsal-fin spine (15.6–19.3% SL vs. 8.9–14.9), a shorter dorsal-to-adipose distance (20.2–23.6% SL vs. 23.9–28.1) and lacking (vs. having) a prominent pale midlateral stripe on the body.

Glyptothorax platypogonides  differs from the remaining Sundaic congeners in having a more slender body (depth at anus 12.1–14.8% SL vs. 14.2–23.1); it is additionally distinguished from G. decussatus  in lacking (vs. having) anteromedial striae in the thoracic adhesive apparatus, having a larger eye (diameter 11–14% HL vs. 8–9), a shorter head (25.2–26.8% SL vs. 27.2–30.2), and a deeper caudal peduncle (6.5–7.9% SL vs. 10.3–10.9), and from G. major  in lacking (vs. having) anteromedial striae in the thoracic adhesive apparatus, having a larger eye (diameter 11–14% HL vs. 7–10), a shorter head (25.2–26.8% SL vs. 27.2–31.3) and a more slender caudal peduncle (depth 6.5–7.9% SL vs. 7.7–10.1). It further differs from G. p i c t u s in having a more slender caudal peduncle (depth 6.5–7.9% SL vs. 8.4–10.9) and lacking (vs. having) dark vertical bars at the adipose-fin base and the base of the caudal fin, and from G. platypogon  in having a larger eye (diameter 11–14% HL vs. 7–9), a longer pectoral-fin spine (17.8–22.7% SL vs. 13.6–17.9), a shorter adipose-fin base (10.7–13.7% SL vs. 13.6–18.0), a straight (vs. convex) dorsoposterior margin of the adipose fin, a longer post-adipose distance (17.6–21.5% SL vs. 14.6–17.6) and a longer and more slender caudal peduncle (length 18.0–21.5% SL vs. 15.5–18.2; depth 6.5–7.9% SL vs. 8.0–11.4) Glyptothorax platypogonides  is further distinguished from G. prashadi  in having a narrower head (17.0–20.5% SL vs. 20.2–22.8), a concave (vs. straight) margin of the dorsal fin, a more slender body (depth at anus 12.1–14.8% SL vs. 15.8–18.8) and a more slender caudal peduncle (6.5–7.9% SL vs. 8.3–10.3), from G. robustus  in having (vs. lacking) a medial pit in the thoracic adhesive apparatus, a longer dorsal-to-adipose distance (20.2–23.6% SL vs. 16.9–20.4) and lacking (vs. having) prominent dark longitudinal stripes running through each lobe of the caudal fin, and from G. s t i b a ro s in having a smooth (vs. serrated) posterior margin of the dorsal-fin spine and a shorter adipose-fin base (10.7–13.7% SL vs. 14.6–17.8).

TABLE 12. Morphometric data for Glyptothorax platypogonides (n = 20).

  Mean±SD
  64.2±2.01
  13.1±0.80
  14.4–17.1
  21.6–25.5 23.7±1.26
  25.9–31.8
  12.2±0.96
  17.6–21.5
  18.0–21.5
  13.4±0.90
  25.2–26.8 26.0±0.49
  17.0–20.5 18.3±1.09
Outer mandibular barbel length
RMNH

National Museum of Natural History, Naturalis

ANSP

Academy of Natural Sciences of Philadelphia

UMMZ

University of Michigan, Museum of Zoology

ZRC

Zoological Reference Collection, National University of Singapore

Kingdom

Animalia

Phylum

Chordata

Class

Actinopterygii

Order

Siluriformes

Family

Sisoridae

Genus

Glyptothorax

Loc

Glyptothorax platypogonides (Bleeker 1855)

Ng, Heok Hee & Kottelat, Maurice 2016

2016
Loc

Glyptothorax lampris

Jiang 2011: 280

2011
Loc

Glyptosternum platypogonoides

Beaufort 1913: 267

1913
Loc

Glyptothorax platypogonides

Jiang 2011: 280
Tan 2000: 292
Kottelat 1993: 77
Fowler 1904: 500

1904
Loc

Glyptothorax platypogonoides

Fowler 1915: 220
Hubrecht 1887: 11

1887
Loc

Glyptosternon platypogonides

Bleeker 1858: 219

1858
Loc

Pimelodus platypogonides

Bleeker 1855: 260