Phylum Porifera
Class Demospongiae
Order Hadromerida
Family Suberitidae
Prosuberites geracei van Soest & Sass, 1981
Taxonomic Characterization: Superficially smooth. Blue or grayish blue in
color. Lateral expansion indefinate. Ecotsome is thin, organic, microhispid with
single, projecting spicules. No evident oscules (van Soest & Sass, 1981).
Disposition of Specimens: National Museum of Natural History, Smithsonian
Institution, catalog numbers USNM 31746; and Zoological Museum Amsterdam catalog
number POR 4580
Ecological Classification: Stygobitic
Size: Spicule size 190-340.5-555 by 3.5-8.5-18 micrometers.
Number of Species in Genus: Three, all marine
Genus Range:
- Bahama Islands: P. geracei van Soest &
Sass, 1981
- San Salvador Island: P. geracei van
Soest & Sass, 1981
- Holland: P. epiphytum (Lamarck, 1813)
reported in van Soest, 1977
- United States:
- Florida: P. microsclerus de Laubenfels,
1936
- West Indies: P. epiphytum (Topsent, 1933)
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Species Range: Known only from Lighthouse Cave, San Salvador Island,
Bahamas.
Closest Related Species:
Habitat: Anchialine limestone caves
Ecology: Found encrusting calcareous rocks and limestone cave walls that
are barely covered at low tide by fully marine salinity waters. Found with two
other marine sponges, Pellina pencilliformis
van Soest & Sass, 1981 and Cinachyra
subterranea Van Soest & Sass, 1981. In addition, Lighthouse Cave is
inhabited by species of cirolanid isopods, phoronid worms, ostracods,
gastropods, amphipods and more. Requires a vegetation of fucoid algae.
Evolutionary Origins: It is believed that this species of sponge
originated from a marooned population of a marine shallow-water species at least
23,000 years ago. Such a rate of speciation seems quite high, when compared to
the evidence of slow evolution in tropical sponges. On the other hand, the cave
situation very likely speeded up the development of morphological changes due to
inbreeding (van Soest & Sass, 1981).
Conservation Status: Restricted to a single anchialine cave
References:
- de Lamarck, J.B.P.A. 1813-1817. Sur les polypiers
empatees. Annls. Mus. Hist. nat. Paris, 20:294-312, 370-386,
432-458.
- de Laubenfels, M.W. 1936. A discussion of the
sponge fauna of the Dr Tortugas in particular, and the West Indies in
general, with material for a revision of the families and orders of the
Porifera. Publs. Carnegie Instn., 467 (Pap. Tortugas Lab.,
30):i-iii, 1-225, pls. I-XXII.
- van Soest, R.W.M. and D.B. Sass. 1981. Marine
sponges from an island cave on San Salvador Island, Bahamas. Bijdragen
tot de Dierkunde, 51(2):332-344, 4 figures, 2 tables.
- Topsent, E. 1933. Eponges de Lamarck conservees
au Museum de Paris. Fin. Archs. Mus. natn. Hist. nat Paris,
10(6):1-60, pls. I-III.
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