Australian Soleid Flatfish

Taxonomy of the genus microcephalus

As an undergraduate, I took part in an REU program at the Smithsonian Museum of Natural History studying the taxonomy of Australian Soleichthys flatfish. Most of the nominal species of soles placed in Soleichthys were described and remain known only from the holotype or relatively few speciems. Most nominal species of Soleichthys are small flatfishes seldom exceeding 180mm in SL, and most are collected only infrequently using trawls. Unlike many other soleids that have uniformly drab ocularside pigmentation, most species of Soleichthys have conspicuous ocular-side pigmentation patterns featuring either boldly pigmented crossbands and or other conspicuous markings such as blotches and spots. In my research, Soleichthys microcephalus (Günther), which occurs in warm temperate waters off New South Wales, is re-described based on examination of a syntype and additional non-type material. This species differs from congeners in its combination of: low meristic features; in having two elongated ocular-side pectoral-fin rays of nearly equal length; with small scales present on the ocular-side pectoral-fin base and proximal halves of elongated pectoral-fin rays; in its ocular-side pigmentation consisting of a series of 8-10 mostly complete, bold, wide, dark-brown or blackish crossbands of nearly uniform width throughout their lengths and noticeably wider than the alternating lighter-colored crossbands; and with two, conspicuous, mid-lateral white spots arranged in horizontal series. Two previously unrecognized species phenotypically most similar to S. microcephalus are described from specimens collected in tropical waters of northern Australia. Soleichthys serpenpellis n.sp., known from the Gulf of Carpentaria and Delambre Island, Dampier Archipelago, northwestern Australia, is distinguished from S. microcephalus and other congeners by the combination of: an ocular-side head and body pigmentation featuring incomplete, diamond-shaped crossbands broadest in their mid-sections; fewer (about 6) ocular-side body crossbands; small, brown spots scattered in the interspaces between crossbands; and by some of its meristic features. Soleichthys oculofasciatus n.sp. occurs off northeast Australia and is distinguished from congeners in its combination of: a first elongate ocular-side pectoral-fin ray longer than the second; in lacking scales on the ocular-side pectoral-fin base and elongate pectoral-fin rays; in some of its morphometric features; in having a longitudinal series of crossbands (usually 11) on the ocular-side head and body; and with four conspicuous white spots on the body, two of which are arranged in a vertical series at mid-body.


PDF - Two new soleid flatfishes (Pleuronectiformes: Soleidae: Soleichthys) from Australian waters, with a re-description of Soleichthys microcephalus (Günther)