Macromaxillocarididae

Lore & Background

Macromaxillocaris bahamaensis was described in 2006 by Fernando Alvarez, Thomas M. Iliffe and José Luis Villalobos in the Journal of Crustacean Biology. The authors erected a new family, Macromaxillocarididae, within the infraorder Stenopodidea. This was the first major addition to the taxonomy of the infraorder since the family Spongicolidae was created by Frederick Schram in 1986. The name Macromaxillocaris derives from Greek and Latin roots meaning 'long jaw shrimp', referring to the exceptional length of its third maxilliped.

The species is a troglobite, known only from an anchialine pool in Oven Rock Cave on Great Guana Cay in the Bahamas. The cave was first explored in 1993 and contains at least 20 species of stygobiont, making it a hotspot of subterranean biodiversity. The entrance leads to a small lake 1.5 m deep, connected to an underwater room and further passages extending over 300 m. Water salinity ranges from 28.3 ppt at the surface to 33–35 ppt at 12 m depth. The shrimp is thought to live on the cave ceiling or in fissures, as it was only observed by divers returning to the surface, presumably dislodged by exhaust bubbles.

Like other troglobitic species, the body lacks pigments and the eyes are vestigial. It has chelae on the first three pairs of pereiopods, as do other stenopodideans, but differs by the greatly enlarged third maxilliped, which is the strongest of all its appendages.

Reader's Guide

Macromaxillocarididae holds significance as the first troglobitic family within the Stenopodidea, expanding the known ecological diversity of the infraorder. Its discovery in an anchialine pool in Oven Rock Cave highlights the importance of cave systems as biodiversity hotspots, with the cave hosting at least 20 stygobiont species. The family's defining feature—the greatly enlarged third maxilliped—distinguishes it from all other stenopodideans and is reflected in its name. The taxonomic description in 2006 represented the first major addition to stenopodidean taxonomy since 1986, underscoring the rarity of such discoveries. The species' troglobitic adaptations, including lack of body pigment and vestigial eyes, align it with other cave-dwelling crustaceans. Its habitat in a salinity-stratified anchialine pool and its elusive behavior (observed only when dislodged by divers) provide insights into the specialized ecology of subterranean marine shrimp. The family remains monotypic, with Macromaxillocaris bahamaensis as its sole representative.

Did You Know?

• Macromaxillocaris bahamaensis is the only species in the family Macromaxillocarididae.
• It was the first troglobitic species discovered among the Stenopodidea.
• Its third maxilliped is greatly enlarged and is the strongest of all its appendages.
• The species was described in 2006 by Alvarez, Iliffe, and Villalobos in the Journal of Crustacean Biology.