Taxonomic composition and assemblage structure of brachiopods from two submarine caves in the Aegean Sea, Eastern Mediterranean

Abstract

Brachiopods exhibit a particular preference for cryptic habitats such as submarine caves. However, their assemblages have rarely been investigated quantitatively in this habitat. In this work, brachiopod assemblages were studied in detail for the first time in two Aegean submarine caves, Fara and Agios Vasilios, Lesvos Island, Eastern Mediterranean Sea. Six species of Recent brachiopods, i.e. Novocrania turbinata (Poli, 1795), Tethyrhynchia mediterranea Logan, 1994, Megathiris detruncata (Gmelin, 1791), Argyrotheca cuneata (Risso, 1826), A. cistellula (Searles–Wood, 1841), and Joania cordata (Risso, 1826), have been identified. The cave-exclusive species Tethyrhynchia mediterranea is reported for the first time from the Aegean Sea and Greek waters, increasing the regional brachiopod fauna to 13 species, and for the second time in the Eastern Mediterranean. Five species were present in both caves while T. mediterranea was found only in the internal dark ceilings and walls of Fara cave. In both caves the dominant species was Argyrotheca cuneata. Abundance and diversity increased towards the internal dark ceilings of both caves, which harboured a well-differentiated brachiopod assemblage compared to that of the outer cave zones.