Sclerobiont assemblages on macro-invertebrates from the Cenomanian strata of Djebel Bouarif (Aurès Range, Algeria)

Abstract

ABSTRACT The ichnological study of the Djebel Bouarif Cenomanian deposits (Northern Aurès Range, Algeria) revealed relatively abundant and diverse sclerobiont communities that are preserved in corals, bivalves and gastropods. Fossil traces are dominated by exceptionally preserved Gastrochaenolites, often with tracemakers (bivalves), which are preserved in situ, Entobia, and Maeandropolydora. Other borings are rare and are represented by a single specimen of Rogerella, Nihilichnus, and Spirolites. Among sclerozoans, encrusting juvenile oysters and non-oyster bivalves (Pseudolimea? granulata) are the most abundant groups. Other epibionts, such as gastropods and polychaetes (Glomerula serpentina), are less common; dwarf gastropods were located on a single oyster Costagyra olisiponensis, whereas Glomerula specimens were clustered on the lower and upper surfaces of coral Aspidiscus cristatus. Gastrochaenolites with original tracemakers and all the epibionts studied herein have not been described from the Djebel Bouarif Cenomanian deposits to date. The rare occurrences of Spirolites and Nihilichnus are reported from Algeria for the first time.