Isopisthus

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
Isopisthus parvipinnis
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Acanthuriformes
Family: Sciaenidae
Genus: Isopisthus
Gill, 1862
Type species
Ancylodon parvipinnis

Taxonomy

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 (fish{|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 publsihed total length of 41.6 cm (16.4 in), while that of the silver weakfish is 36 cm (14 in)>[6]

Distribution and habitat

Isopisthus is found in the western Atlantic and eastern Pacific. The bigtooth corvina occurs in shallow inshore waters over sandy mud or soft mud substrates from Costa Rica to southern Brazil.[9] The silver weakfish is found in inshore waters and outer estuarine areas from Baja California and the Gulf of California to Peru.[10]

Fisheries and conservation

Isopithus fishes are caught by fisheries. The silver weakfish is targeted by commercial and artesinal fisheries and has shown declines in the amount landed and the size of the fishes landed but it is still a common species with a wide range and is classified as Least Conccern by the IUCN.[11] The bigtooth corvina is not targeted by fisheries but is caught as bycatch in shrimp trawl fisheries, although it is not of great commercial value and the catch is mainly used as bait. This species is also classified as Least Concern.[12]

References
  1. Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Genera in the family Sciaenidae". Catalog of Fishes. California Academy of Sciences. Retrieved 10 May 2023.
  2. Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species in the genus Isopisthus". Catalog of Fishes. California Academy of Sciences. Retrieved 12 May 2023.
  3. Kunio Sasaki (1989). "Phylogeny of the family Sciaenidae, with notes on its Zoogeography (Teleostei, Peciformes)" (PDF). Memoirs of the Faculty of Fishes Hokkaido University. 36 (1–2): 1–137.
  4. J. S. Nelson; T. C. Grande; M. V. H. Wilson (2016). Fishes of the World (5th ed.). Wiley. pp. 497–502. ISBN 978-1-118-34233-6.
  5. Christopher Scharpf & Kenneth J. Lazara, eds. (9 March 2023). "Series Eupercaria (Incertae sedis): Families Callanthidae, Centrogenyidae, Dinopercidae, Emmelichthyidae, Malacanthidae, Monodactylidae, Moronidae, Parascorpididae, Sciaenidae and Sillagidae". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf and Kenneth J. Lazara. Retrieved 12 May 2023.
  6. Froese, Rainer and Pauly, Daniel, eds. (2023). Species of Isopisthus in FishBase. February 2023 version.
  7. Aguilera, Orangel; Schwarzhans, Werner & Béarez, Philippe (2016). "Otoliths of the Sciaenidae from the Neogene of tropical America". Palaeo Ichthyologica. 14: 7–90.
  8. "Genus: Isopisthus, Shortfin Corvina Croaker, Weakfishes, Corvinas". Shorefishes of the Greater Caribbean online information system. Smithsonian Tropical Research Institute. Retrieved 12 May 2023.
  9. Froese, Rainer; Pauly, Daniel (eds.) (2023). "Isopisthus parvipinnis" in FishBase. February 2023 version.
  10. Froese, Rainer; Pauly, Daniel (eds.) (2023). "Isopisthus remifer" in FishBase. February 2023 version.
  11. Chao, L.; Espinosa-Perez, H.; and Bearez, P. (2020). "Isopisthus remifer". IUCN Red List of Threatened Species. 2020: e.T183342A130937638. doi:10.2305/IUCN.UK.2020-2.RLTS.T183342A130937638.en. Retrieved 12 May 2023.
  12. Aguilera Socorro, O. (2020). "Isopisthus parvipinnis". IUCN Red List of Threatened Species. 2020: e.T47147702A82679809. doi:10.2305/IUCN.UK.2020-2.RLTS.T47147702A82679809.en. Retrieved 12 May 2023.
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