Creaseriella anops

Phylum Arthropoda
Subphylum Crustacea
Class Eumalacostraca
Order Isopoda
Family Cirolanidae

Creaseriella anops (Creaser, 1936)

Synonyms: Cirolana anops Creaser, 1936

Taxonomic Characterization: A large stygobitic cirolanid isopod without eyes and pigment, able to roll into a ball. Head oblong; twice as wide as long; posterior margin very slightly concave. Second and third pereional segments equal; about half the length of the first pereional segment. Fourth, fifth, sixth and seventh pereional segments subequal. First pair of antennae with two segments in peduncle; flagellum with about 26 segments. Second pair of antennae with five segments in peduncle; flagellum with 40 segments. Six distinct pleonal segments. Greatest breadth of isopod, about half total length. Color in life, white (Creaser, 1936).

Ecological Classification: Stygobitic

Size: Body length to 21.8 mm

Number of Species in Genus: One

Genus Range:

Species Range: Known from numerous cenotes and caves in the states of Quintana Roo and Yucatan.

Habitat: Freshwater and anchialine limestone caves

Ecology: Creaseriella anops inhabits caves or semi closed cenotes where light is absent. Specimens have been found from the surface to depths of more than 50 m, mostly in freshwaters, although some specimens have been caught in baited traps from marine waters below the halocline. They can readily be collected with baited traps. Most often they are observed on the bottom, but they can move up into the water column when disturbed.

Life History: Penes on mid-ventral surface of seventh pereional segment consisting of two filaments. Female similar to male, marsupial plates not prominent.

Evolutionary Origins: Derived from marine forms during the early Pleistocene (Wilkens, 1982).

Conservation Status: Widespread in numerous caves in the states of Quintana Roo and Yucatan. This species is listed as threatened in the official Mexican endangered species list - la Norma Oficial Mexicana (NOM-059-ECOL-2001).

References:

Botosaneanu, L. and T.M. Iliffe. 2002. Stygobitic isopod crustaceans, already described or new, from Bermuda, the Bahamas, and Mexico. Bulletin de L’Institut Royal des Sciences Naturelles de Belgique, Biologie, 72:101-112.
Creaser, E.P. 1936. Crustaceans from Yucatan. Carnegie Institution of Washington Publications, 457:117-132, 43 figures, 3 tables.
Pérez-Aranda, L. 1984. Cirolanidae: Cirolana anops. Fauna de los Cenotes de Yucatan, No. 7, Universidad de Yucatan, Merida, 13 pp., 3 figures, 4 maps, 1 table.
Rioja, E. 1953. Observaciones sobre los cirolanidos cavernicolas de Mexico (Crustaceos, Isopodos). Annales del Instituto de Biologia de México, 24(1):147-170
Wilkins, H. 1982. Regressive evolution and phylogenetic age: The history of colonization of freshwaters of Yucatan by fish and Crustacea. Association of Mexican Cave Studies Bulletin, 8:237-243.