ANARHYNCHIA (JURASSIC BRACHIOPODA) IN A POSSIBLE SEEP DEPOSIT FROM BEDFORD CANYON, CALIFORNIA, USA

The enigmatic occurrence of Anarhynchia gabbi Ager in isolated carbonate lenses in the Santa Ana Mountains 110 km SW of Los Angeles, California, has attracted sporadic attention over the past four decades since Silberling et al. (1959) described the type locality. The material was originally considered Triassic in age but Jurassic molluscan fossils from one of the carbonate outcrops in Bedford Canyon has led to the brachiopods generally being considered of Jurassic age too. In addition, brachiopods considered Anarhynchia cf. gabbi by Sandy (Little et al. 1999) from the hydrothermal vent Figueroa deposit of California are considered Early Jurassic (late Pleinsbachian to middle Toarcian) on the basis of microfossil evidence (Little et al., 1999). Lithologic and paleontologic samples made in 1995 have been investigated and the status of Anarhynchia as a distinct genus confirmed (Sandy 2001). Dagys and Manceñido (1992) had previously considered Anarhynchia a possible junior synonym of Peregrinelloidea from Siberia. Anarhynchia has an East Pacific distribution, having been recorded in scattered carbonate deposits from California, Oregon, and possibly Argentina. A review of fossil brachiopods currently considered to be from cold-seep paleoenvironments shows that two morphologies appear to be most common: Morphotype 1 - consisting of coarsely ribbed forms that may have slight or incipient bilobation (e.g. Dzieduszyckia); Morphotype 2 - small (1 - 1.5cm in maximum dimension) brachiopods with a smooth, non-ribbed shell and sulcate anterior commissure. These Morphotypes were identified by Sandy and Campbell 1995.