''Hypoplectrus gemma'', the blue hamlet, is a species of marine
ray-finned fish, a sea bass from 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 ...
Serraninae
The Serraninae is a subfamily of perciform ray-finned fishes in the family Serranidae. It is made up of ten genera and 87 species.
Characters
The fishes in the subfamily Serraninae, the serranines, are small species within the family Serranidae. ...
which is part of the
family Serranidae, which also includes the
groupers and
anthias
Anthias are members of the family Serranidae and make up the subfamily Anthiinae. Anthias make up a sizeable portion of the population of pink, orange, and yellow reef fishes seen swarming in most coral reef photography and film. The name Anthi ...
. It is found in the western Atlantic Ocean and occasionally makes its way into the
aquarium
An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...
trade.
Description
''Hypoplectrus gemma'' has a deep body which is markedly compressed laterally. It has a straight forehead and a rather short snout which has a protrusible top jaw The preoperculum is angular and has serrations along its edges and a number of small spines which point to the head on its lower edge close to the angle. The
dorsal fin has ten spines and 14-17 soft rays and is continuous. It has long
pelvic fin
Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods.
Structure and function Structure
In actinopterygians, the pelvic fin consists of two en ...
s which extend as far as, or beyond the anus. The
caudal fin is slightly forked.
The head, body and fins of this species are plain iridescent blue and there is a black stripe on the upper and lower edges of the caudal fin.
This species has a maximum recorded length of , although the method of
fish measurement
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 ...
used was not given.
Distribution
''Hypoplectrus gemma'' is found in the western Atlantic Ocean. It was considered to be
endemic to
Florida but it has since been discovered off the
Yucatan Peninsula in Mexico,
It has also been found in the
Dutch West Indies off the island of
Bonaire
Bonaire (; , ; pap, Boneiru, , almost pronounced ) is a Dutch island in the Leeward Antilles in the Caribbean Sea. Its capital is the port of Kralendijk, on the west ( leeward) coast of the island. Aruba, Bonaire and Curaçao form the ABC i ...
.
It has also been recorded on the northern Bahamas and in Cuba.
Habitat and biology
''Hypoplectrus gemma'' is found on shallow reefs, at depths of . The species in the genus ''
Hypoplectrus
''Hypoplectrus'' is a genus of fishes commonly known as hamlets, found mainly in coral reefs in the Caribbean Sea and the Gulf of Mexico, particularly around Florida and the Bahamas. They are a popular choice for hobbyist saltwater aquariums, and ...
'' are synchronous
hermaphrodite
In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes.
Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...
s and they have the ability to move between "male" and "female" roles when
spawning.
The colour pattern of this species resembles that of the
blue chromis
''Chromis cyanea'' (blue chromis) is a damselfish in the subfamily ''Pomacentrinae'', found in Bermuda, southern Florida and the Caribbean Sea.
It is collected for the aquarium trade.
Habitat and ecology
Being a shallow water fish, the blue ...
(''Chromis cyanea'') and it has been suggested that the blue hamlet mimics the blue chromis. The resemblance between the two species is enhanced by the more elongate body shape and deeply forked tail of ''H. gemma'' compared to its congeners. The purpose of this mimicry may be to allow ''H. gemma'' to prey on the young of the blue chromis but this has yet to be proven.
[ This is a ]carnivorous
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...
species which feeds on other fishes and non-sessile benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...
crustaceans.[
]
Taxonomy
''Hypoplectrus gemma'' was first formally described in 1882 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, pe ...
ichthyologist
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, 33,400 species of fish had been described as of Octobe ...
s George Brown Goode (1851-1896) and Tarleton Hoffman Bean (1846-1916) with the type locality given as Garden Key in the Dry Tortugas of Florida.
Utilisation
''Hypoplectrus gemma'' is used in the aquarium trade but whether it is rare or common in that trade is unclear.
References
External links
FishIndex.com
ITIS Report
Deep Sea Images Library
{{Taxonbar, from=Q3893396
gemma
Fauna of the Bahamas
Fish described in 1882