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The Sponge Fauna
Cecilia Volkmer-Ribeiro
Museu de Ciências Naturais, Fundação Zoobotânica do Rio Grande do Sul, Rua Dr. Salvador França, 1427. Porto Alegre, RS, Brazil. 90.690-000. cvolkmer@fzb.rs.gov.br .
Sponge taxa (8 spp.):
Class: Demospongidae
Order HAPLOSCLERIDA Gray, 1867
Family Spongillidae Gray, 1867
Genus Trochospongilla Vejdovsky, 1883.
(Fig. 1)
T. paulula (Bowerbank, 1863 )
(Fig. 2)
T. delicata Bonetto & Ezcurra de Drago , 1967
T. variabilis , Bonetto & Ezcurra de Drago 1973
T. minuta (Potts, 1887)
T. lanzamirandai Bonetto & Ezcurra de Drago, 1964.
Genus Radiospongilla Penney & Racek, 1968
R. amazonensis Volkmer-Ribeiro & Maciel, 1983
Genus Heteromeyenia Potts, 1881
H. sp.
(Figs 3-4)
Genus Corvoheteromeyenia Ezcurra de Drago, 1979
C. heterosclera Ezcurra de Drago, 1974
(Figs 5-6)
Genus Houssayella Bonetto & Ezcurra de Drago, 1966
H. sp.
Photographs:
Fig. 1 - Spiny leaves of the palm tree Astrocaryum jauari collected at the river banks, and showing encrustation with a scanty skeleton and many gemmules of sponges of genus Trochospongilla. Photo: Dan Shain.
Fig. 2 - A close-up of the spines on the leaves of the palm tree Astrocaryum jauari showing abundant gemmules produced by the sponge Trochospongilla paulula at this seasonally flooded vegetation, one of its preferred substrates. Photo: Dan Shain.
Fig. 3 - Minute living specimen of Heteromeyenia sp. encrusting a decaying stem of Eichhornia crassipes at the floating meadows. This specimen bears evidence of being the result of sexual reproduction, since no gemmules were seen close to it that could have given origin to this specimen. Photo by Dan Shain.
Fig. 4. Close-up of Heteromeyenia sp. (from Fig. 3) showing the oscular appertures and the sponge pinacoderm charged with its peculiar microscleres. Photo by Dan Shain.
Fig. 5. Living Specimen of Corvoheteromeyenia heterosclera with recently formed gemmules. The sponge makes up the poriferan assembly of the floating meadows and in this case was encrusting the submerged stem of Eichhornia crassipes.
Fig. 6. Close-up of Corvoheteromeyenia heterosclera (from Fig. 5) showing the thin pinacoderm which covers the sponge surface Photo by Dan Shain.
Abstract of research findings:
Preliminary results of the first survey of freshwater sponges ever carried out in the Peruvian Amazon and in Perú are reported. Extensive surveys and studies of sponges have been already published for the Brazilian and the Venezuelan Amazon. The present work reports the farthest western portion of the sponge fauna in the Amazonian realm. The results of the taxonomic analysis are presented according to three categories of sampling approaches, i.e., sediments, floating meadows, and seasonally flooded forest above the river banks. The area surveyed in the Rio Pacaya evinced three different habitats occupied by sponges: floating meadows along the main river channels, macrophytes along smaller waterways and oxbow lakes, and seasonally flooded forest above the level of the river banks. Nine species of sponges were collected, all members of the family Spongillidae. Neotropical freshwater spongillids are characterized by a highly delicate morphology and inhabit areas protected from strong water currents. That is precisely the most outstanding characteristic of the Ucamara meandering rivers. Exposure of sponges to grazing by fishes may explain the poverty of specimens found alive in the low water period. Fishes reported to feed on freshwater sponges are Leporinus obtusidens , Hipostomus regania , Megalancystrus aculeatus and Sternarchogiton nattereri . A new species of Houssayella was discovered from gemmules and sparse skeleton spicules adhering to the rachi of palm leaves in flooded forests along the margins of oxbow lakes. No species were detected in the Families Potamolepidae or Metaniidae, which possess strong and heavy silicious skeletons. The sponge fauna in seasonally flooded forests of the Rio Pacaya seems to be exceptionally poor in comparison to varzea lakes of Rio Juruá in the Brazilian Amazon. The sponge fauna of floating meadows in the Rio Pacaya is however quite similar in species composition to that of the inner delta of River Jacuí in extreme southern Brazil (Tavares et al., 2003).
Phylogeny and Biogeography:
The Neotropics is the location of the richest freshwater sponge fauna on Earth. There are at least 16 phylogenetically independent clades of Neotropical freshwater sponges (Appendix ). The Family Spongillidae is represented by about 30 Neotropical species in 14 genera ( Spongilla 2 extant spp., including the circumtropical S. alba , and one fossil sp.; Eunapius 1 circumtropical sp.; Radiospongilla 1 sp.; Anheteromeyenia 1 sp.; Ephydatia 2 extant spp. and 1 fossil endemic sp.; Racekiella 1 sp.; Trochospongilla 9 spp.; Heteromeyenia 3 spp., Corvoheteromeyenia 2 spp.; Dosilia , 1 sp.; Saturnospongilla 1 sp.; Corvospongilla 2 spp.; Heterorotula 1 sp.; and Houssayella 1 sp.). Three of these genera are Neotropical endemics (i.e., Saturnospongilla; Corvoheteromeyenia, and Houssayella ). Representatives of at least four spongillid genera ( Spongilla , Eunapius , Trochospongilla and Heteromeyenia ) are present in both the Neotropics and Paleotropics, each, representing a phylogenetically independent clade in Neotropical freshwaters. Eunapius fragilis is cosmopolitan. The 3 species of Ephydatia are endemic to Neotropical freshwaters though the genus is cosmopolitan. Saturnospongilla is the sister taxon to Trochospongilla . Saturnospongilla is probably a hybrid produced and persisting in the Amazon basin through asexual gemmular reproduction (Volkmer-Ribeiro, 1976). The Family Metaniidae includes 12 recognized Neotropical species. The genus Metania exhibits a Gondwanan distribution with five species in the Amazon basin (Volkmer-Ribeiro & Costa, 1992), three in Africa (Silva & Volkmer-Ribeiro, 2001), one in India, one in Borneo, and one in Australia (Volkmer-Ribeiro & Costa, 1993). Of the four other members of the Metaniidae, Acalle (1 sp.) is endemic to the Amazon basin, and Drulia (5 spp., all endemic to South America) has a larger distribution in Northern South America . These distributions suggest an origin for the family in the western portion of Gondwana before the separation of South America and Africa in the Upper Cretaceous (c. 100 Ma.). In addition to several morphological features all members Metaniidae share two unusual characteristic among sponges: living close to or at the water-air surface, and the capacity to withstand high temperatures (25-30° C), and seasonal droughts with several months of aerial exposure, both features which allow members of this clade to inhabit lowland tropical river floodplains. The Family Potamolepidae also presents a Gondwanan distribution (Volkmer-Ribeiro & De Rosa-Barbosa, 1979 ). Eleven species of South American potamolepids are known, and the Neotropics is a center of diversity for the group. Uruguaya + Oncosclera are monophyletic and are the sister taxon to the African clade Potamolepis + Potamophloios . All Neotropical potamolepids prefer rocky bottoms habitats of large rivers. Potamolepids are absent from the Palearctic, which has the poorest overall species diversity of freshwater sponges.
Publications:
Batista, T.C.A., Volkmer-Ribeiro, C., Darwich, A. & L.F. Alves. 2003. Freshwater sponges as indicators of floodplain lake environments and of river rocky bottoms in Central Amazonia , Amazoniana 17(3/4): 525-549.
Volkmer-Ribeiro, C., Albert, J., Tavares, M.C.M., Coral, A.L. 2003. Sponge assemblies at floating meadows from tropical and sub-tropical South America . CD. Resumos. IX Congresso Brasileiro de Limnologia, 20-25/07/03. ICB-UFJF, Juiz de Fora, MG. Resumo 270.
Other References:
Silva, C.M.M. & Volkmer-Ribeiro, C. 2001. Key to the Ethiopian species of the genus Metania Gray, 1867 (Porifera, Metaniidae) with redescription of Metania rhodesiana and M. godeauxi , comb.n. Bulletin de L´Institut Royal des Sciences Naturelles de Belgique., Biologie, Bruxelles, 71:127-138.
Tavares, M.C.M., Volkmer-Ribeiro, C. & De Rosa-Barbosa, R. 2003. Primeiro registro de Corvoheteromeyenia australis ( Bonetto & Ezcurra de Drago) para o Brasil com chave taxonômica para os poriferos do Parque Estadual Delta do Jacuí, Rio Grande do Sul, Brasil. Revista Brasileira de Zoologia 20(2):169-182.
Volkmer-Ribeiro, C. 1976. A new monotipic genus of Neotropical freshwater sponges (Porifera-Spongillidae) and the evidence of a speciation via Hybridism. Hydrobiologia, 50,3: 271-281.
Volkmer-Ribeiro, C.1986. Evolutionary study of the freshwater sponge genus Metania Gray,1867: III - Metaniidae, New Family. Amazoniana, 9,4:493-509.
Volkmer-Ribeiro, C. 1990. A new insight into the systematics, evolution and taxonomy of freshwater sponges. In: Ruetzler, K. (ed) New Perspectives in sponge biology. Washington , 1990; 323-331.
Volkmer-Ribeiro, C. & Costa, P.R.C. 1992. On Metania spinata (Carter, 1881) and Metania kiliani n. sp.: Porifera, Metaniidae Volkmer-Ribeiro,l986. Amazoniana, Kiel, XII, 1:7-16.
Volkmer-Ribeiro, C. & Costa, P.R.C. 1993. Redescription of the Oriental and Australian species of the genus Metania Gray, 1867 (Porifera: Metaniidae). Iheringia, Ser.Zool. Porto Ale gre , 74:81-101.
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