Oplopomus

Lore & Background

The genus Oplopomus was first used by German zoologist Christian Gottfried Ehrenberg for Oplopomus pulcher, a synonym of Oplopomus oplopomus, which was first described by French zoologist Achille Valenciennes in 1837. The name was made available through subsequent usage by Austrian zoologist Franz Steindachner in 1860. The genus has been classified under the subfamily Gobiinae of the goby family Gobiidae, although the 5th edition of Fishes of the World does not recognize any subfamilies in Gobiidae.

Oplopomus species have elongated bodies and compressed heads, with 24 to 30 ctenoid scales on the body that become cycloid on the nape before disappearing just behind the eyes. Their snouts are short and round, smaller than the diameter of the eyes. The lower jaw protrudes past the upper jaw, and a pair of canine teeth is present on each side. The dorsal fins are separated, with six rays on the first; the ventral fins are joined by a frenum; and the caudal fins are round. They can grow to a maximum length of 10 cm.

Oplopomus superficially resembles members of the genus Acentrogobius, but can be distinguished by having the first rays of both dorsal fins ending in a sharp point (pungent). The two recognized species are Oplopomus caninoides and Oplopomus oplopomus, the latter known as the spinecheek goby.

Reader's Guide

Oplopomus represents a small but distinctive genus within the goby family, notable for its morphological adaptations to coral reef habitats. The genus is found from the Red Sea to the Pacific Ocean, inhabiting depths of 1 to 30 meters. Its two species, Oplopomus caninoides and Oplopomus oplopomus, share key traits such as elongated bodies, compressed heads, and a protruding lower jaw with canine teeth. The presence of a frenum joining the ventral fins and the pungent first rays of both dorsal fins are diagnostic features that separate Oplopomus from the similar genus Acentrogobius.

The taxonomic history of Oplopomus involves contributions from several prominent zoologists. Christian Gottfried Ehrenberg first used the name for Oplopomus pulcher, which later became a synonym of Oplopomus oplopomus, originally described by Achille Valenciennes. Franz Steindachner subsequently made the genus name available through his usage. The classification of Oplopomus within the subfamily Gobiinae is standard, though the 5th edition of Fishes of the World does not recognize subfamilies in Gobiidae, reflecting ongoing taxonomic debate.

Ecologically, Oplopomus species are part of the diverse goby fauna of Indo-Pacific coral reefs. Their maximum length of 10 cm places them among the smaller reef fishes, and their ctenoid scales and rounded caudal fin suggest a benthic lifestyle. The genus's limited species count and specific morphological traits make it a subject of interest for ichthyologists studying goby diversity and evolution.

Did You Know?

• Oplopomus contains only two recognized species.
• The genus was first used by Christian Gottfried Ehrenberg and made available by Franz Steindachner.
• Oplopomus oplopomus is commonly known as the spinecheek goby.