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Phylum Arthropoda
Subphylum Crustacea
Class Malacostraca
Order Isopoda
Family Gnathostenetroididae

Stenobermuda iliffei Kensley, 1994



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Stenobermuda iliffei: after Kensley, 1994

Taxonomic Characterization: The cephalon has well produced anterolateral processes and a triangular, apically subacute rostrum. The eye consists of 4 close-set ommatidia and the pleon consists of 2 short anterior pleonites and a shield-shaped pleotelson that is narrow posterior to the lateral tooth. The antenna is about 1.25 times the body length with a flagellum with 50 articles. The antennule has 7 articles. The mandible lacks a horn-like process and the mandibular molar is distally truncate (Kensley, 1994).

Disposition of Specimen: Type specimens were deposited in the United States National Museum; ovigerous female holotype (USNM 243589) and paratypes (USNM 243590, 243591).

Ecological Classification: Stygobitic

Size: Body length of male ranges from 2.1-3.0 mm, body length of female 2.9 mm. Body length, width ratio 3.5-3.6.

Number of Species in Genus: Four, two of which are stygobitic (S. iliffei and S. mergens).

Genus Range:

  • Andros Island, Bahamas
    • Conch Sound Blue Hole: S. mergens Botosaneanu & Iliffe, 1999
  • Bermuda: S. acutirostrata Schultz, 1978; S. iliffei Kensley, 1994
  • Caicos Islands: S. acutirostrata Schultz, 1978 reported in Schotte, Heard & Kensley, 1991
  • South Africa: S. syzygus (Barnard, 1940)

Species Range: Known only from Walsingham Cave, Hamilton Parish, Bermuda (Kensley, 1994).

Closest Related Species: S. iliffei, S. acutirostrata and S. mergens are closely related species.

Habitat: Anchialine limestone caves

Ecology: Walsingham Cave has tidal exchange originating from Castle Harbour flow through the entrance pool.

Life History: The 22 available specimens of the protogynous hermaphrodite S. iliffei can be grouped by size and reproductive structures:

  • 8 females (1.2-1.6 mm) with pleopodal operculum containing male pleopod 1 precursors
  • 12 primary males (2.1-3.2 mm) with male pleopods
  • 2 secondary males (2.9 mm) with empty marsupium and male pleopods

Evolutionary Origins: S. iliffei and S. mergens are hypogean offshoots of S. acutirostrata, a shallow water marine species widely distributed in the Western Atlantic. Possibly other subterranean adapted species will be discovered in hypogean habitats inside the distribution area of the marine species. Colonization of subterranean aquatic habitats by shallow water marine elements in Gnathostenetroididae and Stenetrioidea is considered as being a general phenomena (Wägele, 1990).

Conservation Status: Restricted to a single anchialine cave in Bermuda.

References:

  • Botosaneanu, L. and T.M. Iliffe. 1999. A simple scenario for stygobitization in Stenobermuda Schultz, 1978 (Isopoda Asellota Stenetriidae), with description of a new species from Andros Island. International Journal of Speleology, 26: 37-45, 9 figures.
  • Kensley, B. 1994. Records of shallow-water marine isopods from Bermuda with descriptions of four new species. Journal of Crustacean Biology, 14(2): 319-336.
  • Schotte, M., R.W. Heard and B. Kensley. 1991. Studies of the Crustacea of the Turks and Caicos Islands, British West Indies. III. Records of marine Isopoda for Pine Cay, Fort George Cay, Water Cay, and adjacent waters. Gulf Reseach Reports, 8(3): 251-257.
  • Schultz, G.A. 1978. A new Asellota (Stenetriidae) and two, one new, Anthuridea (Anthuridae) from Bermuda (Crustacea: Isopoda: Asellota). Proceedings of the Biological Society of Washington 91(4): 904-911.
  • Serov, J.H. and R. Vonk. 1990. A review of the Stenetriidae (Crustacea: Isopoda: Asellota). Records of the Australian Museum 47: 39-82.
  • Wägele, J.W. 1990. Aspects of the evolution and biogeography of stygobiontic Isopoda. Bijdragen tot de Dierkunde, 60(3/4): 145-150.

Contributor: Brian Kensley, National Museum of Natural History, Washington, DC


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