Bagrichthys hypselopteru

Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, Journal of Natural History 34, pp. 267-303 : 270

Bagrichthys hypselopteru s (Bleeker, 1852)

Bagrus hypselopterus Bleeker, 1852d: 588 (type locality: Palembang , Sumatra).

Bagrichthys hypselopterus: Weber and de Beaufort, 1913: 346 , ®gure 146 (in part); Kottelat et al., 1993: 63, pl. 29.

Material examined. BATANG HARI DRAINAGE: ZRC 40472 (1), 242.0 mm SL. ZRC 41532 (15), 166.1±279.5 mm SL. ZRC 41898 (1), 208.8 mm SL.

Remarks. Males can be di erentiated from the females in possessing an elongate genital papilla and in having longer nasal and maxillary barbels (nasal-barbel length 63.8±78.2 mm HL vs 45.1±51.0; maxillary-barbe l length 96.6±106.7 vs 78.5±87.7). The gut contents of ®ve specimens were examined and the guts were found to be distended with ®ne silt from the river bed, although chironomid larvae and pupae (Diptera) were also found in small quantities (D. H. Murphy, personal communication). This seems to suggest that B. hypselopterus feeds by ingesting large amounts of silt from the river bed while targeting aquatic arthropods. We note that the dentition of B. hypselopterus is rather unique and consists of long and slender teeth that are markedly exposed from the gum (especially in the lower jaw). This dentition seems to suggest a less carnivorous diet compared to most other cat®shes and, together with the contents of the gut, seemingly con®rms Roberts’ (1989) contention that B. hypselopterus is a detritus feeder.