Bahadzia williamsi

Phylum Arthropoda
Subphylum Crustacea
Class Malacostraca
Order Amphipoda
Family Hadziidae

Bahadzia williamsi Holsinger, 1985

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

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 third maxillipedal palp segment is only slightly widened distally.
The female's palm of the second gnathopod is not strongly oblique.
The third mandible palp segment has A-setae.
The peduncle of uropod one has a proximoventral spine.
The distal end of the peduncle of uropod 2 has a comb row of five small spines and several longer spines.

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

Bahadzia williamsi from Holsinger, 1985

Disposition of Specimens: National Museum of Natural History, Smithsonian Institution; Zoölogisch Museum Amsterdam; San Diego Natural History Museum, California; and in the private collection of John Holsinger.

Ecological Classification: Stygobitic

Size: Females range from 5.5 to 8.5 mm in length, but rarely exceed 7.0 mm. Males do not exceed 6.0 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 Dan's Cave, Great Abaco Island; Asgard Cave, Sweetings Cay; Bahama Cement Cave and Lucayan Caverns, Grand Bahama Island - all located on the Little Bahama Bank.

Closest Related Species: B. obliqua. 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 caves

Ecology: Free-swimming at a depth of 10 to 16 m in polyhaline waters (18 ppt) below the halocline. The oxygen concentration at this depth is very low, less than 1 ppm.

Life History: Several females were observed having setose brood plates. One was ovigerous. The brood pouch contained one large egg, but three detached eggs were found in the collection bottle. Amphipods 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 allied 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 the Little Bahama Bank.

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.