Comparisons. Besides G. amnestus, whose differences with G. plectilis are already outlined in the diagnosis, there are six other congeners known from Sumatra: G. famelicus, G. f u s c u s, G. keluk, G. ketambe, G. platypogonides and G. s c h m i d t i. Glyptothorax plectilis is further distinguished from G. famelicus, G. platypogonides and G. schmidti in having a deeper body (depth at anus 15.3 – 18.8 % SL vs. 11.4 – 15.7), a deeper caudal peduncle (8.4 – 10.6 % SL vs. 5.8 – 8.7) and a shorter post-adipose distance (14.0 – 17.6 % SL vs. 17.6 – 22.0), from G. famelicus in having a greater predorsal length (35.3 – 40.6 % SL vs. 32.1 – 35.2) and a longer adipose-fin base (12.9 – 17.2 % SL vs. 11.4 – 12.8), and from G. f u s c u s in having a concave (vs. straight) margin of the dorsal fin. It further differs from G. keluk in having a straight (vs. convex) dorsoposterior margin of the adipose fin, from G. ketambe in having a wider head (18.4 – 23.5 % SL vs. 16.1 – 17.9), a deeper body (depth at anus 15.3 – 18.8 % SL vs. 12.7 – 15.3) and a shorter caudal peduncle (13.4 – 19.9 % SL vs. 20.1 – 22.9), and from G. schmidti in having a shorter dorsal-to-adipose distance (17.9 – 23.5 % SL vs. 23.9 – 28.1), and lacking (vs. having) a prominent pale midlateral stripe on the body. Among the remaining Sundaic congeners, G. plectilis further differs from G. exodon in having the premaxillary tooth band approximately two-thirds (vs. almost entirely) exposed when the mouth is closed, a wider (18.4 – 23.5 % SL vs. 16.0 – 18.1) and deeper (15.2 – 19.4 % SL vs. 13.8 – 15.1) head, and a shorter post-adipose distance (14.0 – 17.6 % SL vs. 21.5 – 24.0), from G. nieuwenhuisi in having a deeper caudal peduncle (8.4 – 10.6 % SL vs. 7.0 – 8.4), and from G. p i ct u s in lacking (vs. having) dark vertical bars at the adipose-fin base and the base of the caudal fin. It is further distinguished from G. platypogon in having a straight (vs. convex) dorsoposterior margin of the adipose fin, a longer caudal fin (26.6 – 33.1 % SL vs. 20.1 – 27.0) and the presence (vs. absence) of dark spots on the body, and from G. prashadi in having a concave (vs. straight) margin of the dorsal fin and a shorter caudal peduncle (13.4 – 19.9 % SL vs. 20.1 – 22.2). Glyptothorax plectilis can be further differentiated from both G. robustus and G. stibaros in having a deeper caudal peduncle (8.4 – 10.6 % SL vs. 6.6 – 8.3), from G. robustus in having (vs. lacking) a medial pit in the thoracic adhesive apparatus, and from G. stibaros in having a smooth (vs. serrated) posterior margin of the dorsal-fin spine,
