Two new species ofXylophagafrom Trondheimsfjorden, western Norway (Mollusca, Pelecypoda)

Wooden Stepping Stones: Diversity and Biogeography of Deep-Sea Wood Boring Xylophagaidae (Mollusca: Bivalvia) in the North-East Atlantic Ocean, With the Description of a New Genus

“…Xylophagaids covering broad salinity ranges in the Atlantic and occurring also in the Mediterranean such as Xylonora atlantica new comb., Xylophaga dorsalis and Abditoconus brava are therefore considered euryhaline marine species (Table 4). Turner, 1955;Janssen, 1989;Zenetos et al, 2005; Smith, 1903;Dons, 1929Dons, , 1933Carrozza, 1975;Janssen, 1989;Turner, 2002;Janssen and Krylova, 2014 Xylophaga nidarosiensis 10 m Western Norway Santhakumaran, 1980 Xylophaga noradi 10 m Western Norway Santhakumaran, 1980 Xylonora Turner, 1955Turner, , 2002Romano et al, 2014;Gaudron et al, 2016; this study Turner, 1972;Harvey, 1996;Turner, 2002 Xyloredo Species diversity estimations can be affected by factors that influence seasonal colonization times such as variations of local current regimes or different reproduction and spawning times in different species. Temporal effects became apparent in the eastern Mediterranean because X. dorsalis was the only colonizer in 2007 while A. brava appeared only in 2009 and became the dominant species.…”

“…A few species have been collected repeatedly at different sites, such as Xylophaga dorsalis (Turton, 1819) and Xylophaga atlantica Richards, 1942. Both live in wide geographic areas and from littoral to bathyal depths in the northern Atlantic Ocean (Purchon, 1941;Culliney and Turner, 1976;Santhakumaran, 1980;Voight, 2007). Many other species are only known from single records (Knudsen, 1961;Harvey, 1996;Turner, 2002;Voight, 2007Voight, , 2008, while some occur in abyssal plains or even in deep-sea trenches, thousands of kilometers away from the nearest land mass, where sunken wood is considered extremely rare (Knudsen, 1961;Voight, 2008;Voight and Segonzac, 2012).…”

“…In addition, extraction of the xylophagaids from wood substrates can be challenging and often lead to fragmentation of specimens and damage of their delicate shells. As a result, several species descriptions are based on single or incomplete specimens, lacking information on intraspecific phenotypic variation (Smith, 1903;Knudsen, 1961;Santhakumaran, 1980;Harvey, 1996;Turner, 2002). For these reasons, species determinations relying only on morphological characters can be ambiguous and lead to errors.…”

Deep-sea wood-boring bivalves ofXylophaga(Myoida: Pholadidae) on the Continental Shelf: a new species described

“…Most frequently, deep-sea species make shallow water incursions at high latitudes, where the water column is isothermic. A description of two Xylophaga species from 10 m depth in Norway (Santhakumaran, 1980) indicates that the group shows this pattern, but the description here of a new species of the genus from near 100 m depth on the Pacific coast of Guatemala documents that additional mechanisms are at work. The derived character states of a truncated excurrent siphon that continues as lappets on the dorsal incurrent siphon, and ear-shaped mesoplax plates place this species in Turner's (2002) species Group 6.…”

Paleocene methane seep and wood-fall marine environments from Spitsbergen, Svalbard

“…This is not necessarily for the identifications of these borings, as the calcareous linings produced by teredinids can be very thin and fragile (Turner, 1966), which leaves them prone to dissolution, damage and destruction. On the contrary to teredinids, xylophagains attack the wood on the seabed and are most common in the deep sea (Knudsen, 1961), although not exclusive to it (Santhakumaran, 1980). Great majority of xylophagains do not exceed 10 mm in diameter (Knudsen, 1961) and the borings observed in this study are nearly twice the diameter of usual xylophagain infestations.…”