''Xenocys jessiae'', the black-striped salema, is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

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 h ...

, a grunt belonging to the family

Haemulidae Haemulidae is a family of fishes in the order Perciformes known commonly as grunts. It is made up of the two subfamilies Haemulinae (grunters) and Plectorhynchinae (sweetlips), which in turn contain about 133 species in 19 genera. These fish ar ...

. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

to the eastern Pacific Ocean.

Description

''Xenocys jessiae'' has a relatively slender, elongated body, notably different from most related species. The head is conical in shape and has large eyes and a short diagonal mouth with a protruding lower jaw. It has very small teeth which are set in bands on the flaws and the palate. 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 c ...

is not continuous, the anterior spiny portion is completely divided from the posterior soft- rayed part. The dorsal fin contains 10 spines in the anterior portion and a single spine and 13-14 soft rays. The anal fin has 3 small spines and 10-11 soft rays. This species attains a maximum total length of . The back is dark silvery-grey in colour, frequently showing yellowish green, yellowish blue or blue-green tints. The colour shades to paler silver on the flanks and to silvery-white on the underparts. There are 7 black, horizontal stripes along the flanks.

Distribution

''Xenocys jessiae'' is found in the eastern Pacific Ocean where it is

to the waters around the

Galápagos Islands The Galápagos Islands ( es, Islas Galápagos) are an archipelago of volcanic islands in the Eastern Pacific, located around the Equator west of the mainland of South America. They form the Galápagos Province of the Republic of Ecuador, with ...

Habitat and biology

''Xenocys jessiae'' is found at depths between . It forms dense scoops in these shallow waters. These spend the day along rock walls and over rocky slopes. They feed on

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cr ...

and small fishes. It is an

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), a ...

species,

spawning Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aqua ...

in distinct pairs.

Systematics

Xenocys jessiae was first formally described in 1890 by the American ichthyologists David Starr Jordan (1851-1931) and Charles Harvey Bollman (1868-1889) with the

type locality Type locality may refer to: * Type locality (biology) * Type locality (geology) See also * Local (disambiguation) * Locality (disambiguation) {{disambiguation ...

given as Isla Santa Maria in the Galápagos Islands of Ecuador. This species is placed in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

'' Brachygenys'' by some authorities this was done when ''Haemulon'' was determined to be

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

in molecular studies which showed '' Haemulon chrysargyreum'', the type species of Felipe Poey’s ''Brachygenys'', clustered with '' Xenistius californianus''. The genus was therefore revived to include also includes the other species in ''

Xenistius ''Xenistius'' is a genus of grunts native to the eastern Pacific Ocean. Species The currently recognized species in this genus are: * '' Xenistius californiensis'' ( Steindachner, 1876) (Californian salema) * '' Xenistius peruanus'' Hildebrand, ...

'' and this species. This change has been accepted by Catalog of Fishes but not by Fishbase. The specific name honours Jordan’s second wife Jessie Knight Jordan (1866-1952).

References

External links

* {{Taxonbar, from=Q603452 Haemulinae jessiae Fish described in 1890 Taxa named by David Starr Jordan Taxa named by Charles Harvey Bollman