0000000000122459
AUTHOR
Jean Henri Delance
Succession et remplacements de communautés à brachiopodes en régime de sédimentation discontinue (Jurassique Moyen, Bourgogne, France)
Abstract Sequence stratigraphy throws a new and seminal light on the fossil record and helps in determining the respective role played by external control (community replacement) and internal control (paleoecological succession) in the temporal “train” of marine benthic paleocommunities. Five brachiopod-dominated communities (C1–C5) are recognized and their temporal “train” described, during the uppermost Bathonian-lower Callovian interval in Burgundy. The first series (C1–C3) exhibits a trend interpreted as a paleoecological succession and the next two (C3–C4, C4–C5) as community replacements. Within the scope of sequence stratigraphy, the paleoecological succession comes at the end of a t…
Drilling predation on Gryphus vitreus (Brachiopoda) off the French Mediterranean coasts
Abstract A total of 145 valves of Gryphus vitreus with naticid drillholes have been recorded from samples during 21 cruises in the Northwestern Mediterranean, out of about 30,000 empty valves. Drilling was lower than 1% in all stations, except in one station where it reached up to 25.5%. Selectivity of drillhole site by the naticid Euspirella pulchella seems to apply in G. vitreus as drillholes are mainly concentrated in the relatively meaty distal half of the shell, which is also the thickest part of the valve (about 0.6–2 mm). Attacks occur generally on the ventral valve (86.2%) according to the life position of Gryphus. The predation pressure on G. vitreus by drilling appears exceptional…