Species boundaries and phylogenetic relationships between Atlanto-Mediterranean shallow-water and deep-sea coral associated Hexadella species (Porifera, Ianthellidae)

• Published in: Molecular Phylogenetics and Evolution
• Main Authors: Réveillaud, Julie, Remerie, T., van Soest, Rob W. M., Erpenbeck, Dirk, Cárdenas, P., Derycke, Sofie, Xavier, J. R., Rigaux, A., Vanreusel, Ann
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2010
• Subjects: Phylogenetic resolution; Atlanto-Mediterranean; Porifera; Cold-water corals; COI; Nuclear intron; Partial 28S rDNA; Greenland; Greenland Sea
• Online Access: http://hdl.handle.net/10261/56563; https://doi.org/10.1016/j.ympev.2010.03.034

11 páginas, 5 figuras, 2 tablas. Coral reefs constitute the most diverse ecosystem of the marine realm and an increasing number of studies are focusing on coralspeciesboundaries, distribution, and on processes that control species ranges. However, less attention has been paid to coralassociatedspecies. Deep-sea sponges dominate cold-watercoral ecosystems, but virtually nothing is known about their molecular diversity. Moreover, speciesboundaries based on morphology may sometimes be inadequate, since sponges have few diagnostic characters. In this study, we investigated the molecular diversity within the genus Hexadella (Porifera, Demospongiae, Verongida, Ianthellidae) from the European shallow-water environment to the deep-seacoral ecosystems. Three molecular markers were used: one mitochondrial (COI) and two nuclear gene fragments (28S rDNA and the ATPS intron). Phylogenetic analyses revealed deeply divergent deep-sea clades congruent across the mitochondrial and nuclear markers. One clade contained specimens from the Irish, the Scottish, and the Norwegian margins and the Greenland Sea (Hexadella dedritifera) while another clade contained specimens from the Ionian Sea, the Bay of Biscay, and the Irish margin (H. cf. dedritifera). Moreover, these deeply divergent deep-sea clades showed a wide distribution suggesting a connection between the reefs. The results also point to the existence of a new deep-seaspecies (Hexadella sp.) in the MediterraneanSea and of a cryptic shallow-waterspecies (Hexadella cf. pruvoti) in the Gorringe Bank. In contrast, low genetic differentiation between H. cf. dedritifera and H. pruvoti from the MediterraneanSea was observed. All Hexadella racovitzai specimens from the MediterraneanSea (shallow and deep) to the Atlantic formed a monophyletic group. The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007–2013) under the HERMIONE project, grant agreement No. 226354. J.R. had a Special Research Fund (BOF) from ...