Abstract
BackgroundAmong all present demosponges, lithistids represent a polyphyletic group with exceptionally well-preserved fossils dating back to the Cambrian. Knowledge of their recent diversity, particularly in the Tropical Western Atlantic Ocean (TWA) where they are common in deep waters, is scarce making any comparison between present and past major ‘lithistid’ faunas difficult. In addition, the lack of sufficient molecular and morphological data hamper any predictions on phylogenetic relationships or phylodiversity from this region. The Harbor Branch Oceanographic Institute (HBOI, Fort Pierce, Florida) holds the largest collection of TWA lithistid sponges worldwide, however, the majority remain to be taxonomically identified and revised.Principal FindingsIn this study we provide sequences of 249 lithistid demosponges using two independent molecular markers (28S rDNA (C1-D2) and cox1 mtDNA). In addition, a morphological documentation of 70 lithistid specimens is provided in the database of the Sponge Barcoding Project (SBP). This integrated dataset represents the largest and most comprehensive of the TWA lithistids to date. The phylogenetic diversity of ‘lithistid’ demosponges in the Bahamas and Jamaica are high in comparison to other TWA regions; Theonellidae and Corallistidae dominate the fauna, while Neopeltidae and Macandrewiidae are rare. A proposed tetractinellid suborder, one undescribed genus and several undescribed species are recognized and the Pacific ‘lithistid’ genera, Herengeria and Awhiowhio, are reported from the TWA for the first time. The higher-taxa relationships of desma-bearing tetractinellids are discussed and topics for revision suggested.ConclusionThis first integrative approach of TWA ‘lithistid’ demosponges contributes to a better understanding of their phylogenetic affinities, diversity and bathymetric distribution patterns within the TWA. As in the Pacific, the TWA ‘lithistid’ demosponges dominate deep-water habitats. Deeper taxonomic investigations will undoubtedly contribute to a better comparison between present major ‘lithistid’ faunas and their fossil record in the Mesozoic.
Highlights
Among all present demosponges, lithistids represent a palaeontologically important polyphyletic group, with exceptionally well-preserved fossils dating back to the Cambrian (e.g., Pisera, 2002; Pisera, 2006), and several relict genera represented in living faunas today (e.g., Lévi, 1991; Pisera, 2002; Kelly, 2007; Kelly et al, 2003)
While ‘lithistid’ demosponges in the Tropical Western Atlantic (TWA) are reported from continental shelves, caves and slopes by Van Soest & Stentoft (1988), Reed & Pomponi (1997), and Pomponi et al (2001), and many earlier reports of individual species (e.g., Sollas, 1888), the fauna is still poorly known with few descriptions and no molecular data
Sponge samples were collected from the Tropical Western Atlantic (TWA) using the Johnson-Sea-Link manned submersibles with permission granted to Harbor Branch Oceanographic Institute by: the United States National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Dry Tortugas National Park and the Florida Keys National Marine Sanctuary; the Government of the Bahamas, Department of Fisheries; the Government of Honduras, Department of Fisheries (DIGEPESCA-638/97); the Government of Portugal, Parque Natural de Madeira; the Government of Jamaica, Jamaican Ministry of Foreign Affairs; the Government of Bonaire, Bonaire Marine Park, and Netherlands Ministry of Foreign Affairs
Summary
Lithistids represent a palaeontologically important polyphyletic group, with exceptionally well-preserved fossils dating back to the Cambrian (e.g., Pisera, 2002; Pisera, 2006), and several relict genera represented in living faunas today (e.g., Lévi, 1991; Pisera, 2002; Kelly, 2007; Kelly et al, 2003). While ‘lithistid’ demosponges in the TWA are reported from continental shelves, caves and slopes by Van Soest & Stentoft (1988), Reed & Pomponi (1997), and Pomponi et al (2001), and many earlier reports of individual species (e.g., Sollas, 1888), the fauna is still poorly known with few descriptions and no molecular data This greatly limits the understanding of their phylogenetic relationships, diversity and evolution. Lithistids represent a polyphyletic group with exceptionally well-preserved fossils dating back to the Cambrian Knowledge of their recent diversity, in the Tropical Western Atlantic Ocean (TWA) where they are common in deep waters, is scarce making any comparison between present and past major ‘lithistid’ faunas difficult.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
