''Branchiostoma bennetti'', the mud lancelet, is a

lancelet The lancelets ( or ), also known as amphioxi (singular: amphioxus ), consist of some 30 to 35 species of "fish-like" benthic filter feeding chordates in the order Amphioxiformes. They are the modern representatives of the subphylum Cephalochord ...

of the genus ''

Branchiostoma ''Branchiostoma'' is one of the few living genera of lancelets (order Amphioxiformes). It is the type genus of family Branchiostomatidae. These small vaguely eel- or snake-like animals are close relatives of vertebrates. The scientific name me ...

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 else ...

to the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

, where it is found in the northern part.

Description

Like other lancelets in the genus ''Branchiostoma'', ''B. bennetti'' occurs in inshore waters where it burrows into sand or muddy sand at depths down to about . The body is laterally flattened and pointed at both ends. It has a long dorsal fin and another fin on its ventral surface, and a caudal fin at the rear end. ''B. bennetti'' differs from other western Atlantic lancelets for having the longest buccal cirri among them. These cirri are further unique in this region because of their extended lateral projections. It is presumed that these unique buccal cirri are an adaptation to living in a muddier habitat than other species.

References

Cephalochordata Animals described in 1966 {{chordate-stub