Prehendocyclops monchenkoi Rocha, 2000
Prehendocyclops monchenkoi: after Rocha et al., 2000
Taxonomic Characterization: Characteristic of the genera
Prehendocyclops is having an antennal prehensile device formed by a stout
curved spine on the third segment, and the three proximalmost appendages of the
terminal segment modified into stout, heavily serrate spines; the distalmost
spine of these is claw-shaped. Additionally, on the praecoxal arthrite of the
maxillule the two outermost apical spines are curved towards a strong, straight,
pointed spine inserted on the inner surface of the arthrite. P. monchenkoi
differs from other species of Prehendocyclops in that the dorsal setae is
1/4 of the length of the outer middle apical seta. Other differences include
number of integumental sensilla on the first urosomal somite, and the genital
double somite in both sexes, shape and size of elements composing the prehensile
device of the antenna; armament of labrum and mandible, ornamentation of some
setae on the maxillular endopod; and the structure of leg 5 in both sexes (Rocha
et al., 2000).
Diposition of Specimens: National Museum of Natural History, Smithsonian Institution, catalog numbers USNM 287094-6, Museu de Zoologia of the University of Sao Paula, catalog number MZUSP 13060, and El Colegio de la Frontera Sur, catalog number ECO-CHZ 00498.
Ecological Classification: Stygobitic
Size: Female body length, excluding caudal setae, measures between 0.505-0.650 mm. Adult male length, excluding caudal setae, measures 0.5-0.55 mm.
Number of Species in Genus: Three
Species Range: Known only from Grutas de Santa Maria, Homun; Grutas de
Tzab-Nah, Tecoh; Cenote Yuncu, all in the State of Yucatan and from Cenote Tos
Virlol, in the State of Quintana Roo, Mexico.
Closest Related Species: P. boxshalli
Habitat: Anchialine limestone caves
Ecology: Found free-swimming and at the sandy bottom of cave pools at depths of 0-8 m. Prehendocyclops has modified mouthparts and antenna like its sister genera Colpocyclops and Smirnoviella, which enable the genera to externally parasitize a host. Thus, Rocha et al assumed that Prehendocyclops is probably also parasitic, although the possible host is unknown.
Life History: Not known. Only 7 females and 5 males have been collected.
Evolutionary Origins: Prehendocyclops and sister genera Smirnoviella and Colpocyclops, which evolved in esturaries connected to the Caspian and Black Sea, were linked in the past as part of the Tethys Sea. Considering that the three genera have similar mouthparts and antenna, they are probably derived from one or more ectoparasitic Halicyclops-like ancestral forms (Rocha et al., 2000).
Conservation Status: Restricted to caves in the Yucatan Peninsula
Contributor: Carlos Eduardo F. da Rocha, Universidade de São Paulo,
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