Auchenipterichthys Bleeker, 1862

Ferraris Jr, Carl J., Vari, Richard P. & Raredon, Sandra J., 2005, Catfishes of the genus Auchenipterichthys (Osteichthyes: Siluriformes: Auchenipteridae); a revisionary study, Neotropical Ichthyology 3 (1), pp. 89-106 : 90

Auchenipterichthys Bleeker, 1862

Auchenipterichthys Bleeker, 1862 (in Bleeker, 1862 -63): 7. Type species: Auchenipterus thoracatus Kner, 1857 . Type by original designation. Gender: Masculine.

Diagnosis. A genus of the Auchenipteridae characterized by the following combination of characters: eye large, midlateral, and visible in both dorsal and ventral views; anal fin with long base and at least 18 branched fin rays; lateral surface of body with several vertically-oriented rows of pale spots above the lateral line; caudal fin emarginate or obliquely truncate; pelvic fin with eight or nine branched rays; and adipose fin present.

Remarks. At present, no derived characters have been identified that are unique to the species of Auchenipterichthys (see Ferraris, 1988; Soares-Porto, 1994; de Pinna, 1998). Instead, the characters listed in the diagnosis are derived characters within the Auchenipteridae (except for the presence of the adipose fin, which is primitive), each of which is also present in at least one other genus in the family, but that occur in common only in the species of Auchenipterichthys . In the absence of an identified unique synapomorphy it is possible that Auchenipterichthys is non-monophyletic; however, no evidence has been advanced to date to suggest that the genus is not natural. In the absence of evidence to the contrary we continue to treat the included species as a single, presumably natural, genus.

Based on overall similarity, the species of Auchenipterichthys fall into two groups. One group, which consists of A. coracoideus and A. thoracatus , has the ventral surface of the coracoid bone covered only by a thin integument ( Figs. 1a, b ) and thus appears to be exposed to the body surface, has eight branched pelvic-fin rays, and has an obliquely-truncate caudal-fin margin. The second group, which includes A. longimanus and A. punctatus , has a thick layer of integument superficial to the ventral margin of the coracoid, such that the coracoid is not visible on the body surface ( Fig. 1c ), has nine branched pelvic-fin rays, and, in most individuals, has a caudal fin that is emarginate and symmetrical (some larger specimens exhibit a truncate fin margin). Because the monophyly of Auchenipterichthys has yet to be established, future studies of the relationships within the Auchenipteridae should include a representative species from each of these two groups so as to determine whether the groups cluster together as a natural unit.

Sexual dimorphism. Sexual dimorphism in the species of Auchenipterichthys includes the enlarged urogenital orifice in females, whereas the urogenital pore of males is located at the distal tip of an elongated tube that is bound by integument to the anterior margin of the anal fin. Males also have an elongated and enlarged posterior unbranched and anterior branched anal-fin rays and elongated spinules along the anterior and posterior margins of the distal part of the dorsal-fin spine. Nuptial males of at least one species ( A. coracoideus ) have an elongated dorsal-fin spine. Species of Auchenipterichthys lack the ossification of the maxillary barbel, elongation of the unbranched pelvic-fin ray, and presence of keratinaceous unculi on dorsal surface of the head, abdomen and maxillary barbel that are found in some other genera of auchenipterids (Ferraris and Vari, 1999, Vari and Ferraris, 1998, Akama and Ferraris, 2003).

Figures

Fig. 1. Ventral view of anterior portion of body of (A) Auchenipterichthys coracoideus, ANSP 178446, 94 mm SL; (B) A. thoracatus, FMNH 57798, 89 mm SL; and (C) A. longimanus, INHS 61570, 67 mm SL; showing different degrees of exposure of coracoid in that region. Line points to exposed coracoids.