Xenocys Jessiae
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''Brachygenys jessiae'', the black-striped salema, is a
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of marine
ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...
, a
grunt Grunt, grunts or grunting may refer to: Sound and music * Grunting (tennis), in tennis refers to the loud noise, sometimes described as "shrieking" or "screaming", made by some players during their strokes * Death grunt, the death metal singi ...
belonging to the family
Haemulidae Haemulidae is a family (biology), family of fishes in the order (biology), order Perciformes known commonly as grunts. It is made up of the two subfamily, subfamilies Haemulinae (grunts) and Plectorhynchinae (sweetlips), which contain about 133 ...
. It is
endemic Endemism is the state of a species being found only 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 foun ...
to the eastern Pacific Ocean.


Description

''Brachygenys 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 on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...
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

''Brachygenys jessiae'' is found in the eastern Pacific Ocean where it is
endemic Endemism is the state of a species being found only 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 foun ...
to the waters around the
Galápagos Islands The Galápagos Islands () 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 a population of sli ...
.


Habitat and biology

''Brachygenys jessiae'' is found at depths between . It forms dense schools 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 that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...
and small fishes. It is an
oviparous Oviparous animals are animals that reproduce by depositing fertilized zygotes outside the body (i.e., by laying or spawning) in metabolically independent incubation organs known as eggs, which nurture the embryo into moving offsprings kno ...
species,
spawning Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is ...
in distinct pairs.


Systematics

''Brachygenys jessiae'' was first formally described in 1890 by the
American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, p ...
ichthyologists Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 35,800 species of fish had been described as of March 2 ...
David Starr Jordan (1851-1931) and Charles Harvey Bollman (1868-1889) with the type locality given as Isla Santa Maria in the Galápagos Islands of Ecuador. This species is placed in the
monotypic 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 "unispe ...
'' Xenocys'' by some authorities. This was done when ''Haemulon'' was determined to be
paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...
in molecular studies which showed ''
Haemulon chrysargyreum ''Haemulon chrysargyreum'', the smallmouth grunt, bronze grunt, or yellowstripe grunt, is a species of marine ray-finned fish, a grunt belonging to the family Haemulidae. It is found in the western Atlantic Ocean. Description ''H. 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'' and this species. This change has been accepted by Catalog of Fishes but not by Fishbase. The
specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...
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