Pseudohomaloptera Silas 1953

Pseudohomaloptera Silas 1953

(Figures 3 E, 4B, 5E, 14)

Pseudohomaloptera Silas, 1953:204. (type species: Homaloptera tatereganii Popta 1905:180, by original designation). Gender feminine.

Remarks. Homaloptera tatereganii Popta 1905 was designated as the type species for the genus Pseudohomaloptera by Silas (1953). Pseudohomaloptera was distinguished from Homaloptera by the “presence of a rostral groove and other structures associated with the mouth” (Silas 1953:205). Tan (2009) recognized Pseudohomaloptera as a junior synonym of Homaloptera, since all species of Homaloptera (sensu lato) have a rostral and postoral groove to varying degrees. Kottelat (2012) recognized H. tatereganii as a species of Balitoropsis and treated Pseudohomaloptera as a junior synonym of Balitoropsis.

Pseudohomaloptera is morphologically very similar to Balitoropsis, and the mouth characters given by Silas (1953) cannot differentiate the two genera. Tan (2009) gave a simple pelvic-fin ray count of 3 for H. tatereganii to distinguish it from species of Homaloptera (s.l.), which have 2 simple pelvic-fin rays. However, the holotype, the only known specimen of H. tatereganii (RMNH 7632), has only 2 simple pelvic-fin rays (on both sides). Other counts that differ from those given by Tan (2009) are the following: iii, 8½ vs. ii, 8 dorsal-fin rays; ii, 5½ vs. ii, 5 anal-fin rays; vii, 12 vs. viii, 12 pectoral-fin rays; 18 vs. 14 circumpeduncular scale count; and 6/7 vs. 5/6 transverse scale count. The following measurements differ from Tan (2009) (owing likely to different methods): predorsal length 44.1% vs. 45.3% SL; body depth 12.5% vs. 10.4% SL; dorsal-fin base 16.7% vs. 18.8% SL; pectoral-fin length 29.4% vs. 28.5% SL; head depth 48.2% vs. 42.8% HL; head width 81.3% vs. 78.3% HL; snout length 61.9% vs. 57.2% HL; 15.1% vs. 14.5% HL; 40.3% vs. 37.7% HL.

Diagnosis. Distinguishing characters are given in Table 4 and shown in Figures 3 E, 4B, 5E, and 14. Pseudohomaloptera is distinguished by the following combination of characters: without reddish tints on fins in life (Fig. 3 E); dorsal-fin origin anterior to or above pelvic-fin origin; 8½ branched dorsal-fin rays; 8–9 branched pelvic-fin rays; forked caudal fin; keeled scales (Fig. 4 B); 50–61 total lateral-line scales; 13–19 predorsal scales; anus closer to anal-fin origin than to pelvic-fin insertion; no adipose keel on caudal peduncle; large rostral cap; 2 thick rostral barbels in close proximity to one another; thick and triangular/crescentic upper lip; fleshy pad between lateral portions of lower lip (Fig. 5 E).

Species included. Pseudohomaloptera tatereganii (Popta 1905), P. sexmaculata (Fowler 1934), P. leonardi (Hora 1941), P. yunnanensis (Chen 1978), P. vulgaris (Kottelat & Chu 1988), and P. batek (Tan 2009). Type localities for species of Pseudohomaloptera are shown in Figure 15.

Comparison. Pseudohomaloptera is distinguished from Homaloptera by absence vs. presence of reddish tints on fins in life; 8–9, 8 (M) vs. 7 branched pelvic fin-rays; 13–19 vs. 20–27 predorsal scales.

Pseudohomaloptera is distinguished from Homalopteroides by having dorsal-fin origin anterior to or at pelvicfin origin vs. posterior to pelvic-fin origin; 8½ vs. 6–8½, 7½ (M) branched dorsal-fin rays; large vs. small rostral cap; medial- and lateral-rostral barbels in close proximity to one another vs. barbels widely separated at base; thick vs. thin upper lip; presence vs. absence of fleshy pad between lateral portions of lower lip.

Pseudohomaloptera is distinguished from Homalopterula by having dorsal-fin origin anterior to or at pelvicfin origin vs. posterior to pelvic-fin origin; 8½ vs. 5½ and 7½, 7½ (M) branched dorsal-fin rays; 8–9 vs. 7 branched pelvic fin-rays; keeled vs. smooth scales; 13–19 vs. 28–56 predorsal scales; forked vs. truncated or emarginated caudal fin; absence vs. presence of adipose keel on caudal peduncle; large vs. small rostral cap; medial- and lateralrostral barbels in close proximity to one another vs. widely separated at base; presence of fleshy pad vs. lobes between lateral portions of lower lip.

Pseudohomaloptera is distinguished from Balitoropsis by having anus closer to anal-fin origin than to pelvicfin insertion.

Material examined. Pseudohomaloptera tatereganii: Borneo: RMNH 7632 (holotype of Homaloptera tatereganii). P. sexmaculata: Thailand: ANSP 56374 (holotype of Homaloptera sexmaculata), 56375 (paratypes of Homaloptera sexmaculata) (2), 56402 (holotype of Homaloptera septemmaculata), 56403 (paratype of Homaloptera septemmaculata); UF 183358 (2), 177819 (3), 181170 (3). P. leonardi: Peninsular Malaysia: ZRC 1753 (paratype of Homaloptera leonardi); RMNH 23264 (6), 25921 (4); UF 169909 (3), 235746 (3). P. yunnanensis: China: IHASW 60-VII- 012 (holotype of Balitoropsis yunnanensis). P. vulgaris: China: 788229 (KIZ 1978001047) (holotype of Homaloptera vulgaris), 788225-788227 (KIZ 1978001048-50) (paratypes of Homaloptera vulgaris). P. batek: Borneo: MZB 10990 (holotype of Homaloptera batek); ZRC 51743 (paratype of Homaloptera batek).