Isopisthus
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| Isopisthus | |
|---|---|
.jpg) | |
| Isopisthus parvipinnis | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Acanthuriformes |
| Family: | Sciaenidae |
| Genus: | Isopisthus Gill, 1862 |
| Type species | |
| Ancylodon parvipinnis | |
Isopisthus is a genus of marine ray-finned fishes belonging to the family Sciaenidae, the drums and croakers. These fishes are found in the western Atlantic and eastern Pacific Oceans.
Isopisthus was first proposed as a monospecific genus in 1862 by the American biologist Theodore Gill with Ancylodon parvipinnis, originally described by Georges Cuvier in 1830 with its type locality given as Cayenne, designated as its type species.[1][2] This genus has been placed in the subfamily Cynoscioninae by some workers,[3] but the 5th edition of Fishes of the World does not recognise subfamilies within the Sciaenidae which it places in the order Acanthuriformes.[4]
Etymology
Isopisthus is a combination of isos, meaning "equal", and opisthen, which means "behind", an allusion to the soft-rayed part of the dorsal fin and anal fin of the bigtooth corvina being almost equal in length.[5]
Species
Isopisthus has 2 extant species classified within it:[6]
- Isopisthus parvipinnis (Cuvier, 1830) (Bigtooth corvina)
- Isopisthus remifer Jordan & Gilbert, 1882 (Silver weakfish)
An extinct species was described in 2016 from the Río Banano Formation of Costa Rica:[7]
- †Isopisthus acer Aguilera, Schwarzans & Béarez, 2016
Characteristics
Isopisthus species have an elongated and highly compressed body. They have large eyes and an oblique mouth which has the lower jaw clearly protruding. There are no barbels or pores on the chin. The upper jaw has a pair of robust, curved cacine-like teeth at its tip. The margin of the preoperculum has small serrations and the upper angle of the operculum is incised. The dorsal fin is divided in two separate parts, with a gap between each part. The anal fin is supported by 2 short spines and between 16 and 20 soft rays. The scales are cycloid and the soft-rayed part of the dorsal fin and the anal fin are scaled. The lateral line reaches the centre of the caudal fin.[8] The bigtooth corvina has a maximum published total length of 41.6 cm (16.4 in), while that of the silver weakfish is 36 cm (14 in).[6]