Cheilobarbus Smith, 1841

Skelton, Paul H., Swartz, Ernst R. & Vreven, Emmanuel J., 2018, The identity of Barbus capensis Smith, 1841 and the generic status of southern African tetraploid cyprinids (Teleostei, Cyprinidae), European Journal of Taxonomy 410, pp. 1-29 : 17-19

Genus Cheilobarbus Smith, 1841 stat. nov.

Barbus Daudin, 1805: 58 (in part, non-Daudin: Barbus (Cheilobarbus) capensis Smith, 1841 ).

Barbus (Cheilobarbus) Smith, 1841 : description of pl. X., fig.1 (applied as a subgenus).

Barbus – Jordan 1919: 244.

‘ Pseudobarbus ’ – Yang et al. 2015: 99.

Type species

Cheilobarbus capensis Smith, 1841 ( Fig. 10B )

Included species

Cheilobarbus capensis Smith, 1841 ( Fig. 10B ), known as the witvis or Berg-Breede River whitefish, from the Berg (Atlantic drainage) and Breede Rivers (Indian Ocean drainage); Cheilobarbus serra (Peters, 1864) known as the sawfin or saagvin, from the Clanwilliam Olifants River (Atlantic drainage).

Diagnosis

Cheilobarbus is distinguished from all other southern African tetraploid cyprinine genera by attaining a relatively large size (adult> 150 mm SL vs <150 mm SL), and by having an extended snout as reflected in an elongated lachrymal bone (length 3 × depth vs rectangular-shaped lachrymal length 2 × depth). Cheilobarbus also differs from Sedercypris gen. nov. by an absence of red colour at the base of the fins, in the position of the mouth (subterminal vs terminal) and in the length of the gut (> 1.5 × SL vs <1.5 × SL). Cheilobarbus differs from Amatolacypris gen. nov. in overall size, colour (silvery to olive-bronze vs grey with double black lateral stripe), number of barbels (two pairs vs one pair), number (five vs four) and form of the 3rd and 4th infraorbital bones (narrow and slender vs broad). Cheilobarbus differs from Namaquacypris gen. nov. in the position of the dorsal fin (entirely before anal fin base vs reaching above anal fin base), form of the scales (regular vs thin), and the lack of a membrane between the innermost pelvic rays and the body (vs present). Cheilobarbus differs from Pseudobarbus in having a serrated dorsal-fin unbranched ray (vs simple dorsal-fin unbranched ray), an absence of red patches at the base of the fins (vs presence), no sexual dimorphism in fin size and shape and in the form and expression of nuptial tubercles as adults (vs clear sexual dimorphism in fin size and shape [males with larger fins] and nuptial tubercles [males with large conical tubercles on snout and head, small tubercles on scales and fins]). Cheilobarbus can be separated from all other large sized southern African cyprinids by karyology

(tetraploid vs diploid or hexaploid) the form of the scales (radiate striae vs parallel striae) and a serrated unbranched dorsal-fin ray (vs simple spinous unbranched dorsal-fin ray).

Etymology

The name Cheilobarbus is derived from the Greek ‘ cheilos ’ meaning a margin, lip or brim, and the Latin ‘ barba ’ meaning a beard and referring to the oral barbels. Smith (1841) mentioned the “lips” of these species as being “full and firm”. Gender masculine.

Description

Cheilobarbus is a genus of tetraploid cyprinine fishes with moderately sized, radiately striated scales; an elongated snout with elongated lacrymals, mouth subterminal with firm, well-developed lips, two pairs of simple oral barbels, pharyngeal bones with three rows of hooked pharyngeal teeth, tooth formula 5,3,2-2,3,5; intestine involuted and longer than the SL; dorsal fin positioned over or slightly behind the origin of the pelvic fins, the last simple ray bony weakly or strongly serrated, and eight branched rays; anal fin with three simple rays and five or six branched rays; mature breeding adults of both sexes develop small erupted nuptial tubercles densely scattered over head dorsum and in single rows over the pectoral fin rays; both species breed in male dominated nuptial shoals over gravel and cobbles.

History

Smith (1841) attributed both the large Barbus species he described to a new subgenus Cheilobarbus , i.e., Barbus (Cheilobarbus) capensis and Barbus (Cheilobarbus) marequensis . While the latter species is identified as a Labeobarbus , the former, a tetraploid species, does not belong in Labeobarbus . The type species of the subgenus, B. capensis , was designated by monotypy by Jordan (1919: 244) as first revisor and, therefore, is not a junior synonym of Labeobarbus . The subgenus Cheilobarbus was described by Smith (1841) as follows: “Mouth opening forwards; lips full, and firm; intermaxillary bones slightly extensible; nostrils double; four cirri, two from snout, and one from each angle of mouth; lateral line consisting of a series of small tubes; scales large; dorsal fin short, and commencing slightly in front of base of ventral fins; commencement of anal fin about midway between ventral and caudal fins.” However this description is not diagnostic, e.g., it does not mention the nature of the unbranched dorsal-fin ray nor the nature of the scale radii. In order to institute Cheilobarbus as the genus for these species, an expanded diagnostic definition is required and the species to be included identified along phylogenetic grounds.

Figures

Fig. 10. Species representative of southernAfrican tetraploid cyprinine genera. A. Pseudobarbus afer (Peters, 1864). B. Cheilobarbus capensis Smith, 1841. C. Amatolacypris trevelyani (Günther, 1877) gen.et comb.nov. D. Sedercypris calidus(Barnard, 1938) gen.et comb.nov. E. Namaquacyprishospes (Barnard, 1938) gen. et comb. nov. Photograph credits:A–D by P.H. Skelton (SAIAB); E by R.I. Bills (SAIAB).