Glyptothorax

Ng, Heok Hee & Kottelat, Maurice, 2016, The Glyptothorax of Sundaland: a revisionary study (Teleostei: Sisoridae), Zootaxa 4188 (1), pp. 1-92 : 86-87

Key to the Glyptothorax species of Sundaic Southeast Asia

1. Body uniformly dark, with a prominent pale midlateral stripe................................................... 2

- Body mottled or uniform, without prominent pale midlateral stripe.............................................. 4

2. Thoracic adhesive apparatus short, not reaching to the level of the last pectoral-fin-ray bases.......................... 3

- Thoracic adhesive apparatus long, reaching to or just beyond the level of the last pectoral-fin-ray bases [central Sumatra, Malay Peninsula].............................................................................. G. schmidti

3. Head length 22.6–23.6% SL; caudal peduncle depth 5.8–7.3% SL; preanal vertebrae 19–20 [Danau Toba drainage in northern Sumatra]................................................................................... G. famelicus

- Head length 24.0–25.5% SL; caudal peduncle depth 7.6–8.9% SL; preanal vertebrae 16–17 [ Alas River drainage in northern Sumatra].................................................................................... G. ketambe

4. Presence of anteromedial striae in the thoracic adhesive apparatus in the thoracic adhesive apparatus ( Fig. 1 )............. 5

- No anteromedial striae in the thoracic adhesive apparatus..................................................... 8

5. Prominent dark vertical mark at base of caudal fin in shape of irregular cross [Kayan River drainage in northeast Borneo].............................................................................................. G. decussatus

- Base of caudal fin without dark vertical mark............................................................... 6

6. Anterolateral edge of thoracic adhesive apparatus gently convex; sides of body with prominent, enlarged tubercles [ Alas River drainage in northern Sumatra].................................................................... G. plectilis

- Anterolateral edge of thoracic adhesive apparatus straight or markedy concave; sides of body without prominent, enlarged tubercles............................................................................................ 7

7. Anterolateral edges of thoracic adhesive apparatus almost straight; caudal peduncle depth 9.8–11.2% SL [central Sumatra].............................................................................................. G. amnestus

- Anterolateral edges of thoracic adhesive apparatus markedly concave; caudal peduncle depth 7.7–10.1% SL [southern, west- ern, northern and northeastern Borneo]............................................................... G. major

8. Medial pit in thoracic adhesive apparatus absent; caudal fin with prominent dark longitudinal stripes running through each lobe [western Java and southern Sumatra].............................................................. G. robustus

- Medial pit in thoracic adhesive apparatus present; caudal fin without prominent dark longitudinal stripes running through each lobe................................................................................................ 9

9. Prominent pale patches on body......................................................................... 10

- No prominent pale patches on body...................................................................... 12

10. Body depth at anus 15.4–20.2% SL; caudal peduncle depth 8.4–10.9% SL; prominent dark vertical bars at level of adipose-fin base and base of caudal fin present [southern Borneo]................................................... G. pictus

- Body depth at anus 12.1–15.8% SL; caudal peduncle depth 6.5–7.9% SL; prominent dark vertical bars at level of adipose-fin base and base of caudal fin absent....................................................................... 11

11. Premaxillary toothband almost entirely exposed when mouth is closed [Kapuas River drainage in western Borneo]...................................................................................................... G. exodon

- Premaxillary toothband two-thirds exposed when mouth is closed [central Sumatra, Malay Peninsula].... G. platypogonides

12. Body uniformly colored, without dark spots; dorsoposterior margin of adipose fin convex........................... 13

- Body mottled, with dark spots; dorsoposterior margin of adipose fin straight...................................... 14

13. Pectoral-fin spine length 19.4–22.9% SL; caudal-fin length 26.9–30.7% SL [Sumatra]......................... G. keluk

- Pectoral-fin spine length 13.6–17.9% SL; caudal-fin length 20.1–27.0% SL [Java]........................ G. platypogon

14. Body strongly tapering posteriorly (caudal peduncle depth 3.4–3.8 times in body depth at dorsal-fin origin); posterior margin of dorsal spine serrated [western and northwestern Borneo]............................................ G. stibaros

- Body not strongly tapering posteriorly (caudal peduncle depth 2.1–2.8 times in body depth at dorsal-fin origin); posterior mar- gin of dorsal spine smooth............................................................................. 15

15. Margin of dorsal fin concave [eastern and southern Borneo]........................................ G. nieuwenhuisi

- Margin of dorsal fin straight............................................................................ 16

16. Snout acutely rounded when viewed dorsally; expanded distal tips of neural spines forming series of low bumps anterior to adipose fin; caudal fin with uniform color pattern without hyaline areas and pointed lobes [southeastern Thailand, Malay Pen- insula, central and southern Sumatra]................................................................ G. fus cus

- Snout broadly rounded when viewed dorsally; expanded distal tips of neural spines not forming series of low bumps anterior to adipose fin; caudal fin with with hyaline areas in median fin rays and tips of fin lobes and acutely rounded [northern Malay Peninsula]................................................................................... G. prashadi

Figures

FIGURE 1. Schematic illustration of thoracic adhesive apparatus of Glyptothorax, showing structures defined and mentioned in this study: anterolateral striae (ALS); anteromedial striae (AMS); medial pit (MP) (based on G. plectilis, MZB 4530, 50.2 mm SL).