''Opeatogenys gracilis'' is a species of

clingfish Clingfishes are ray-finned fishes of the family Gobiesocidae, the only family in the suborder Gobiesocoidei of the order Blenniiformes. These fairly small to very small fishes are widespread in tropical and temperate regions, mostly near the coa ...

from the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Gobiesocidae Clingfishes are ray-finned fishes of the family Gobiesocidae, the only family in the suborder Gobiesocoidei of the order Blenniiformes. These fairly small to very small fishes are widespread in tropical and temperate regions, mostly near the coa ...

which is found in the Mediterranean Sea and in the eastern Atlantic Ocean. Suggested common names for this species are the ''pygmy clingfish'' and the ''seagrass clingfish''.

Description

''Opeatogenys gracilis'' has a short snout which is depressed and triangular in shape. Its general shape is rather similar to that of the

two-spotted clingfish ''Diplecogaster bimaculata'', the two-spotted clingfish, is a species of fish in the family Gobiesocidae found in Black Sea, Mediterranean Sea and Atlantic Ocean where it is found on rocks and among seagrass or shell beds. Description The speci ...

(''Diplecogaster bimaculata''). The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

and

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

s are relatively small and situated close to the

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

. The

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

s are modified to form the suction disc, a characteristic of clingfishes. The colour can be greenish or orange with light blue spots and there is a white line along the back. The maximum

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

is .

Distribution

''Opeatogenys gracilis'' occurs only in the northeastern Atlantic Ocean from the coasts of the

Algarve The Algarve (, , ) is the southernmost NUTS statistical regions of Portugal, NUTS II region of continental Portugal. It has an area of with 467,495 permanent inhabitants and incorporates 16 municipalities (concelho, ''concelhos'' or ''município ...

eastwards to the

Levant The Levant ( ) is the subregion that borders the Eastern Mediterranean, Eastern Mediterranean sea to the west, and forms the core of West Asia and the political term, Middle East, ''Middle East''. In its narrowest sense, which is in use toda ...

. Until specimens were collected off southern Portugal, it had been considered to be

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 Mediterranean. Within the Mediterranean, ''O. gracilis'' has been recorded off the coast of Malaga, Spain, Algeria, Cyprus, France, Sicily and off

Sfax Sfax ( ; , ) is a major port city in Tunisia, located southeast of Tunis. The city, founded in AD849 on the ruins of Taparura, is the capital of the Sfax Governorate (about 955,421 inhabitants in 2014), and a Mediterranean port. Sfax has a ...

in Tunisia.

Habitat and biology

''Opeatogenys gracilis'' is found on the leaves of seagrasses such as ''

Posidonia oceanica ''Posidonia oceanica'', commonly known as Neptune grass or Mediterranean tapeweed, is a seagrass species that is endemic to the Mediterranean Sea. It forms large underwater meadows that are an important part of the ecosystem. The fruit is free ...

'' and ''

Cymodocea nodosa ''Cymodocea nodosa'' is a species of seagrass in the family Cymodoceaceae and is sometimes known as little Neptune grass.

'' and on the fronds of

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

, attaching to the leaves or fronds with the sucking disc formed by the modified pectoral fins. It is thought that this small fish only lives for a few years. Adults feed on small invertebrates which also live on the leaves of seagrass. The pelagic larval stage of this species lasts for a mean of 14.6 days. Off Sicily, the preferred prey was found to be

copepod Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...

s of the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Harpacticoida Harpacticoida is an Order (biology), order of copepods, in the subphylum Crustacean, Crustacea. This order comprises 463 genus, genera and about 3,000 species; its members are benthic copepods found throughout the world in the marine environment ...

Taxonomy and etymology

''Opeatogenys gracilis'' is a clingfish and is placed in the family Gobiesocidae. It was originally described as ''Mirbelia gracilis'' by Giovanni Canestrini from a type locality given as the Mediterranean Sea. In 1955,

John Carmon Briggs {{Short pages monitor