Pseudetroplus Bleeker

Pethiyagoda, Rohan, Maduwage, Kalana & Manamendra-Arachchi, Kelum, 2014, Validation of the South Asian cichlid genus Pseudetroplus Bleeker (Pisces: Cichlidae), Zootaxa 3838 (5), pp. 595-600 : 596-599

Pseudetroplus Bleeker

Pseudetroplus Bleeker , in Günther, 1862: 266; type species Etroplus maculatus (Bloch) .

Pseudetroplus Bleeker, 1862: 125 ; type species Etroplus coruchi Cuvier.

Microgaster Swainson, 1839: 171 (non Latreille, 1804).

Diagnosis. Pseudetroplus is distinguished from Etroplus by having 11 (vs. 12–13) pleural ribs; 26–27 (vs. 28–29) total vertebrae; lateral line incomplete (vs. interrupted), with 1–7 (vs. 13–24) pored scales; possessing an occipital prong (vs. possessing an occipital process; Fig. 1D ); postero-dorsal outline of operculum curved, with a well-developed process (postero-dorsal outline of operculum straight, lacking a well-developed process); anterior half of median suture of lower pharyngeal jaw serrated (vs. smooth; Fig. 1B ); base of the lateral arm of lower pharyngeal jaw broad (vs. narrow; Fig. 1B ); first 6 anal-fin pterygiophores arranged anterior to the first 3 (vs. 2) haemal spines ( Fig. 1A ); supraoccipitalexoccipital prong well developed, extending ventrally over half-way across foramen magnum (vs. less-well developed, not extending into foramen magnum; Fig. 1C ). Further, the anterior jaw teeth in Pseudetroplus are acuminate (vs. spatulate in Etroplus ; Fig. 2 ). Pseudetroplus also differs from Etroplus in pigmentation, possessing one or more black blotches on the side of the body (vs. 7–9 prominent dark lateral bars in Etroplus ); possessing two brown stripes on the dorsal fin (vs. lacking stripes on the dorsal fin); and lacking a black patch on the pectoral fin, near its base (vs. black blotch present on base of pectoral fin).

Discussion. The name Pseudetroplus was published both by Bleeker in Günther (1862) and by Bleeker (1862). While the date of publication of the former is 8 November 1862 ( Eschmeyer, 2014), the date of publication of the latter is unknown and must under ICZN (1999) art. 21.3.2 be assumed to be 31 December, 1862. Bleeker (1862) gave the type species as Etroplus coruchi Cuvier, 1830 (type locality: Malabar [Kerala], India), a junior subjective synonym of Chaetodon maculatus Bloch, 1795 (type locality: ponds along the Coromandel coast [Tamil Nadu], India), while Bleeker in Günther (1862) specified the type species as E. maculatus . The statement in Eschmeyer (2014) that "if [Bleeker in Günther] was first, then suratensis is probably the type " is evidently an error, for Günther (1862: 266) wrote: "According to a communication from Dr. v. Bleeker, he intends to separate this species [i.e. E. suratensis ] generically from E. maculatus , retaining the name of Etroplus for the former, and adopting that of Pseudetroplus for the latter [i.e. E. maculatus ]". Cuvier (1830) used the spelling Etroplus coruchi on p. 491 of his text, which indicated plate 136, on which he employed the name Glyphisodon koruschi : as first reviser we here give precedence to the spelling Etroplus coruchi .

Microgaster Swainson, 1839 (type species E. coruchi Cuvier , in Cuvier & Valenciennes, 1830), while a senior synonym of Pseudetroplus , is a junior homonym of Microgaster Latreille (1804: 175) in Hymenoptera .

Sparks (2008) and Stiassny et al. (2001) distinguished the South Asian cichlids from their sister group, the Madagascan genus Paretroplus , by the former possessing more than a single row (vs. only a single row) of teeth in each jaw; the presence of a single lacrimal plate (lachrymal bifurcated in Paretroplus ); and an asymmetrical displacement of the first anal-fin pterygiophore behind and the second in front of the haemal spine complex (vs. first anal-fin pterygiophore in front of and the second behind the haemal spine complex). While our results are consistent with this description, we note that the arrangement of anal-fin pterygiophores differs consistently between Pseudetroplus and Etroplus , with the former having the first 6 pterygiophores falling anterior to the first 3 haemal spines, whereas in the latter the first 6 pterygiophores fall anterior to the first 2 haemal spines: see Fig. 1A ). Furthermore, whereas in both Pseudetroplus and Etroplus all lateral jaw teeth and the inner rows of the anterior teeth are tricuspid, the anterior jaw teeth are acuminate in adult Pseudetroplus and spatulate in adult Etroplus .

Sparks (2008) noted also that the monophyly of the “ Etroplus suratensis + Etroplus canarensis clade” (i.e. Etroplus sensu stricto) was supported by the presence of a blunt snout with a steeply sloping profile in lateral view (particularly in specimens <about 75mm SL); the presence of seven to nine prominent dark lateral bands; and an unique, unreversed character: a prominent black patch on the pectoral fin near its base. These, together with the dental and osteological characters mentioned in the Diagnosis, above, serve to distinguish Pseudetroplus from Etroplus .

Day (1877: 415) noted that specimens of P. maculatus from Madras (the then presidency, now part of Tamil Nadu State, in which the type locality, Tharangambadi, is located) possessed 17–18 dorsal-fin and 11–12 anal-fin spines, whereas those in southern Karnataka possessed 19–20 and 14–15 spines, respectively. Should the populations of Pseudetroplus in the eastern and western regions of the Indian peninsula prove specifically different, the name P. coruchi Cuvier , in Cuvier & Valenciennes, 1830, is available for the latter.

The difference in anterior jaw dentition in Pseudetroplus and Etroplus appears related to diet, the former being piscivorous, whereas adults of the latter feed on filamentous algae, detritus, aquatic plants and diatoms ( Bindu & Padmakumar, 2008).

Figures

FIGURE 1. Osteology of 1, Pseudetroplus maculatus, WHT 11087, 54.6 mm SL, Kerala, India; 2, Etroplus suratensis, WHT 11088, 63.1 mm SL, Bellanwila, Sri Lanka; 3, E. canarensis, WHT 11084, 48.3 mm SL, Natravedi River, Bengal, India. A, Anterior caudal vertebrae and associated structures in right lateral view; B, lower pharyngeal jaw; C, posterior view of neurocranium, showing foramen magnum; D, lateral view of supraoccipital crest and associated structures. Abbreviations: Hsp.1, first haemal spine; Apt 1–2, anal pterygiophore 1–2; La, lateral arm of lower pharyngeal jaw; Ms, median suture of lower pharyngeal jaw in lingual view; Sec.pr, supraoccipital-exoccipital prong; Fm, foramen magnum; Soc.cr, suproccipital crest; occ.pg, occipital prong; occ.pr, occipital process. Scale bar 1 mm.

FIGURE 2. Anterior premaxillary dentition of A, Pseudetroplus maculatus, AMS B. 8099, 70.5 mm SL, Madras (Tamil Nadu), India; B, Etroplus suratensis, AMS I. 4478, 73.4 mm SL, Madras (Tamil Nadu), India; C, E. canarensis, AMS B.8148, 61.5 mm SL, Canara (Karnataka), India.