Bahadzia setimana

Phylum Arthropoda
Subphylum Crustacea
Class Malacostraca
Order Amphipoda
Family Hadziidae

Bahadzia setimana Stock, 1986

Taxonomic Characterization: Amphipod lacking eyes and pigment. B. setimana can be distinguished from other Bahadzia by the following characteristics by:

The lobe of merus of the first gnathopod is not distally produced.
The coxal gills are large.
The female's carpus of the second gnathopod is greater than or equal to the propodus, the palm of the second gnathopod is not strongly oblique, and the posterior margin of the propodus has eight groups of setae.
The third maxillipedal palp segment is only slightly widened distally.
The third mandible palp segment has A-setae.
The peduncle of uropod one does not have a proximoventral spine.
The distal end of the peduncle of uropod 2 has two spines, but does have a comb row of five smaller spines.

A key to the genus is presented in Jaume & Wagner, 1998.

Disposition of Specimens: Zoölogisch Museum Amsterdam collection number ZMA Amphipod 107.882-3.

Ecological Classification: Stygobitic

Size: The female allotype is 7.2 mm and the male holotype is 5.5 mm.

Number of Species in Genus: Nine (8 anchialine and 1 freshwater), all stygobitic

Bahamas:
- Cat Island: B. obliqua Stock, 1986
- Grand Bahama: B. williamsi Holsinger, 1985
- Abaco: B. williamsi Holsinger, 1985
- South Andros: B. setimana Stock, 1986
Caicos Islands:
- Providenciales: B. stocki Holsinger, 1985
Cuba: B. yagerae Ortiz & Perez, 1995
Dominican Republic: B. jaraguensis Jaume & Wagner, 1998
Haiti: B. latipalpus Stock, 1985
Mexico:
- Isla Cozumel: B. bozanici Holsinger, 1992 and B. setodactylus Holsinger, 1992
- Yucatan Peninsula: B. bozanici Holsinger, 1992

Genus range for Bahadzia

Species Range: Known only from Stargate Blue Hole, South Andros Island, Great Bahama Bank, Bahamas.

Closest Related Species: B. stocki. The genus Bahadzia is restricted to the West Indies and Mexico. All species are closely related, and it is unclear if they are distinct species or are subspecies (Stock, 1986). The only freshwater species, B. latipalpus, has the most distinct morphology, while the anchialine species more closely resemble each other.

Habitat: Anchialine limestone cave.

Ecology: Free-swimming at a depth of 35 m in brackish water (18 ppt) below the halocline. Bacterial growth at the halocline may provide a primary food resource for the associated cave fauna.

Life History: Unknown. Most amphipods carry their eggs and juveniles in a brood pouch. They do not have larvae or resting stages. These attributes affect their dispersal capacities and thus, contribute to their endemism.

Evolutionary Origins: The genus Bahadzia is phylogenetically with Mayaweckelia and Tuluweckelia. "It may be an ancient relict derived from an early hadziid fauna in the old Tethyan seaway" (Holsinger et al., 1986).

Conservation Status: Restricted to a single cave; only a single female and male specimen have been collected.

References:

Holsinger, J.R. 1992. Two new species of the subterranean amphipod genus Bahadzia (Hadziidae) from the Yucatan Peninsula region of southern Mexico, with an analysis of phylogeny and biogeography. Stygologia, 7:85-105.
Holsinger, J.R., D. Williams, J. Yager, and T.M. Iliffe. 1986. Zoogeographic implications of Bahadzia, a hadziid amphipod crustacean recently described from anchialine caves in the Bahamas and Turks and Caicos Islands. Stygologia, 2:77-83.
Holsinger, J.R. and J. Yager. 1985. A new genus and two new species of subterranean amphipod crustaceans (Hadziidae) from the Bahamas and Turks and Caicos Islands. Bijdragen tot de Dierkunde, 55(2):283-294.
Jaume, D. and H.P. Wagner. 1998. New cave-dwelling amphipods (Lysianassidae, Hadziidae) from the Dominican Republic (Hispaniola). Contributions to Zoology, 68(1):37-66 19 figures.
Ortíz, M.R. and A. Pérez. 1995. Una nueva especie de anfipodo cavernícola hadzioideo (Amphipoda, Gammaridea) de Cuba. Graellsia, 51:165-168.
Stock, J.H. 1985. Stygobiont amphipod crustaceans of the Hadzioid group form Haiti. Bijdragen tot de Dierkunde, 55:331-426.
Stock, J.H. 1986. Two new amphipod crustaceans of the genus Bahadzia from 'blue holes' in the Bahamas and some remarks on the origin of the insular stygofaunas of the Atlantic. Journal of Natural History, 20:921-933, 5 figures.