Pellina pencilliformis

Phylum Porifera
Class Demospongiae
Order Poecilosclerida
Family Adociidae

Pellina pencilliformis van Soest & Sass, 1981

Taxonomic Characterization: Creeping "stolons" with upright branches, infrequently and irregularly anastomosing. Branches thin walled, hollow, up to 25 cm long, up to 1 cm in diameter; lateral expansion indefinite. Consistency slightly brittle, extremely fragile (van Soest & Sass, 1981).

Disposition of Specimens: National Museum of Natural History, Smithsonian Institution, catalog numbers USNM 31744-5; and Zoological Museum Amsterdam catalog number POR 4579.

Ecological Classification: Stygobitic

Size: Spicule size 342-368.1-390/9-11.1-13. Size of fistules is 25/1 cm

Number of Species in Genus: Eleven, all marine

Genus Range:

Bahama Islands: P. pencilliformis van Soest & Sass, 1981
- San Salvador Island: P. pencilliformis van Soest & Sass, 1981
Indo-Pacific waters: P. polysiphonia Dendy, 1922; P. eusiphonia Ridley, 1884
Madagascar: P. cioniformis Levi, 1956
Mediterranean-Atlantic region: P. semitubulosa (Lieberkuhn, 1859); P. parietalis (Topsent, 1893); P. magna (Vacelet, 1959)
British waters: P. fistulosa Bowerbank, 1866
New Zealand: Adocia semitubulosa Bergquist, 1961
Palau Islands: P. pinella De Laubenfels, 1954
United States:
- California: P. semitubulosa Dickinson, 1945
West Indies: P. nodosa George & Wilson, 1919 and P. carbonaria Lamarck, 1813

Species Range: Known only from Lighthouse Cave, San Salvador Island, Bahamas.

Closest Related Species: Morphologically, P. pencillformis is closely related to P. eusiphonia Ridley, 1884

Habitat: Anchialine limestone caves

Ecology: Found in fully marine salinities on rocks and on soft sediment at the bottom of pools; always submerged, more frequent at depths of 2-3 m. Found with two other marine sponges, Prosuberites geracei 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.

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:

Dendy, A. 1922. Report on the Sigmatotetraxonida collected by H.M.S. "Sea Lark" in the Indian Ocean. In: Reports of the Percy Sladen Trust Expedition to the Indian Ocean in 190, vol. Vii. Trans. Linn. Soc. Lond., (2, Zool.) 18:1-164, pls. I-XVIII.
Levi, C. 1956. Spongiatres des côtes de Madagascar. Mém. Inst. scient. Madagascar, (A) 10:1-23.
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.