''Isopisthus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

es belonging to the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Sciaenidae Sciaenidae are a family of fish in the order Acanthuriformes. They are commonly called drums or croakers in reference to the repetitive throbbing or drumming sounds they make. The family consists of about 286 to 298 species in about 66 to 70 gen ...

, the drums and croakers. These fishes are found in the western Atlantic and eastern Pacific Oceans.

Taxonomy

''Isopisthus'' Was first proposed as a

monospecific genus In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

in 1862 by the American

biologist A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual Cell (biology), cell, a multicellular organism, or a Community (ecology), community of Biological inter ...

Theodore Gill Theodore Nicholas Gill (March 21, 1837 – September 25, 1914) was an American ichthyologist, mammalogist, malacologist and librarian. Career Born and educated in New York City under private tutors, Gill early showed interest in natural histor ...

with ''Ancylodon parvipinnis'', originally described by Georges Cuvier in 1830 with its type locality given as Cayenne, designated as its

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

. This genus has been placed in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Cynoscioninae by some workers, but the 5th edition of ''

Fishes of the World ''Fishes of the World'' by the American ichthyologist Joseph S. Nelson (1937–2011) is a standard reference for fish systematics. Now in its fifth edition (2016), the work is a comprehensive overview of the diversity and classification of the ...

'' does not recognise subfamilies within the Sciaenidae which it places in the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Acanthuriformes Acanthuriformes is an order of ray-finned fishes, part of the Percomorpha clade. Some authorities place the fishes in the order within the Acanthuriformes in the suborders Acanthuroidea and Percoidea of the order Perciformes. Classification The ...

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 A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

and

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

of the bigtooth corvina being almost equal in length.

Species

''Isopisthus'' has 2 extant species classified within it: * '' Isopisthus parvipinnis'' (Cuvier, 1830) (Bigtooth corvina) * ''

Isopisthus remifer ''Isopisthus'' is a genus of marine ray-finned fishes belonging to the Family (biology), family Sciaenidae, the drums and croakers. These fishes are found in the western Atlantic and eastern Pacific Oceans. Taxonomy ''Isopisthus'' Was first propos ...

Jordan Jordan ( ar, الأردن; tr. ' ), officially the Hashemite Kingdom of Jordan,; tr. ' is a country in Western Asia. It is situated at the crossroads of Asia, Africa, and Europe, within the Levant region, on the East Bank of the Jordan Rive ...

Gilbert Gilbert may refer to: People and fictional characters * Gilbert (given name), including a list of people and fictional characters *Gilbert (surname), including a list of people Places Australia * Gilbert River (Queensland) * Gilbert River (South ...

, 1882 (Silver weakfish) An extinct species was described in 2016 from the Río Banano Formation of Costa Rica: * ''

Isopisthus acer ''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. Taxonomy ''Isopisthus'' Was first proposed as a monospecif ...

'' 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 In fish anatomy and turtle anatomy, a barbel is a slender, whiskerlike sensory organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, the hagfish, the sturgeon, the zebrafish, the black dragonfish and some ...

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 This glossary of ichthyology is a list of definitions of terms and concepts used in ichthyology, the study of fishes. A B C ...

has small serrations and the upper angle of the operculum is incised. The dorsal fin is divided in two separate parts, with an gap between each part. The anal fin is supported by 2 short spines and between 16 and 20 soft rays. The scales are

cycloid In geometry, a cycloid is the curve traced by a point on a circle as it rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another curve ...

and the soft-rayed part of the dorsal fin and the anal fin are scaled. The

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial ...

reaches the centre of the

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

. The bigtooth corvina has a maximum publsihed

total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

of , while that of the silver weakfish is >

Distribution and habitat

''Isopisthus'' is found in the western Atlantic and eastern Pacific. The bigtooth corvina is occurs in shallow inshore waters over sandy mud or soft mud substrates from Costa Rica to southern Brazil. The silver weakfish is found in inshore waters and outer estuarine areas from

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

and the

Gulf of California The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja Ca ...

to Peru.

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 The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

. The bigtooth corvina is not targeted by fisheries but is caught as

bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

in shrimp

trawl Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different speci ...

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.

References

{{Taxonbar, from=Q2210943 Sciaenidae Taxa named by Theodore Gill