Abstract

SANCHEZ-BERISTAIN, Francisco  and  REITNER, Joachim. Reptonoditrypa cautica, an encrusting bryozoan in the Cipit olistoliths of the San Cassiano Formation (Triassic, Ladinian/Carnian; NE Italy) and its paleoecological significance. Bol. Soc. Geol. Mex [online]. 2017, vol.69, n.2, pp.409-420. ISSN 1405-3322.  https://doi.org/10.18268/bsgm2017v69n2a6.

Reptonoditrypa cautica Schäfer and Fois is a bryozoan species that constituted an important part of the encrusting/binder guild of the Triassic reefs, mainly in the Ladinian and Carnian. In the Cipit boulders of the St. Cassian Formation, it is usually associated with specimens of the thalamid sponge Cryptocoelia zitteli (a member of the constructor/baffler guild), although it can also be seen forming crusts along with microbialites on top of other species of reef builders. It is worth mentioning that, although the sponge is always linked to the bryozoan, this does not apply for the opposite. It is also worth to pinpoint the absence of Reptonoditrypa cautica in other thin-section samples of reef facies from these boulders, as well as the fact that it is the only kind of microencrusting bryozoan found in about 400 thin sections.

This article explains the paleoecological role played by this species in the reef systems of the St. Cassian Formation.

Keywords : Bryozoans; encrusters; reef guilds; Triassic; St Cassian Formation.