Exumellina bucculenta Fosshagen, 1998
Taxonomic Characterization: The rostrum is a small, rounded plate without filaments. The urosome is 4-segmented in females and 5-segmented in males. The genital double somite has lobe-like extensions ventrally. The last segment of the endopod of the mandible is a leaf-like structure bearing weak setae. The endopod of the maxillule is greatly elongated and thin. Legs 1-4 have two outer spines on the last segment of the exopod. The structure of mandibular and maxillular endopods is unique among calanoids.
Ecological Classification: Stygobitic
Size: Adult females' length range from 0.69 to 0.77 mm. The adult males' length range from 0.61 to 0.69 mm.
Number of Species in Genus: One
Species Range: Known only from Norman's Pond Cave, Norman's Pond Cay, Exuma Cays, Great Bahama Bank, Bahamas
Closest Related Species: It is the only known species within the genus. The genus is most similar to Exumella and Brattstromia. Of the five genera in the family Ridgewayiidae, four are known to inhabit caves.
Habitat: Anchialine limestone cave
Ecology: This species is free-swimming. It was collected at a depth of 6-35 m in fully marine salinity waters (35-36 g/l). Vertical profiling of water column chemistry and selective collections indicated that E. bucculenta might live only in well oxygenated water. Morphological characteristics of E. bucculenta's body and mouthparts indicate that it is planktonic and feeds on soft or flimsy food.
Conservation Status: Restricted to a single cave
Contributor: Audun Fosshagen, University of Bergen, Norway
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