Auchenipterichthys

Auchenipterichthys was first described by Pieter Bleeker in 1862, who designated A. thoracatus (originally described by Kner in 1857 as Auchenipterus thoracatus) as the type species.[1] There are no derived states that is unique to this genus; however, there is no evidence that has been advanced to indicate that this genus is not monophyletic.[1]

There are currently four described species in this genus:[2]

• Auchenipterichthys coracoideus (C. H. Eigenmann & W. R. Allen, 1942)
• Auchenipterichthys longimanus (Günther, 1864)
• Auchenipterichthys punctatus (Valenciennes, 1840)
• Auchenipterichthys thoracatus (Kner, 1858)

The eyes of these catfish are large and can be seen from both above and below the fish. The anal fin has a long base and at least 18 branched fin rays. The side of the body is decorated with vertical rows of spots above the lateral line. The adipose fin is present.[1]

The lateral line has an irregular zigzag pattern. The head is flattened anteriorly with a terminal mouth. There are three pairs of thread-like barbels, one pair maxillary and two pairs mandibular. The dorsal fin and pectoral fins have large spines; the dorsal fin spine has a lower degree of serration than the pectoral fin spines, which is always serrated strongly on the entire length of both margins.[1]

Based on similarities, the species fall into two groups. One group consists of A. coracoideus and A. thoracatus which have a coracoid covered by a thin layer of integument (allowing the coracoid to be seen from below) and an obliquely truncated caudal fin. The other includes A. longimanus and A. punctatus which has a thick layer of skin covering the coracoid and an emarginate or symmetrical caudal fin.[1] A. coracoideus typically has 25 or fewer branched anal fin rays, while A. thoracatus typically has 26 or more branched anal-fin rays. A. punctatus has a body with variably sized dark spots scattered over the body and the fins, while A. longimanus does not.[1]

Species of Auchenipterichthys are sexually dimorphic. Breeding males of A. coracoideus have an elongated dorsal fin spine.[1] In A. longimanus and A. thoracatus, serrae on the end of the dorsal fin spine are proportionally longer in breeding males than in juveniles and females.[1] Also, females have an enlarged urogenital opening. Males have their urogenital opening located at the end of a tube bound by integument to the anterior margin of the anal fin.[1] The males use their modified anal fin as a means of internal insemination; the female can later lay the eggs in isolation.[3]

Auchenipterichthys species are insectivores.[3] A. longimanus has been reported to feed primarily on terrestrial invertebrates.[1] There is also evidence that A. longimanus is involved in seed dispersal.[4] Auchenipterichthys species are also capable of producing sound.[5]