Taphonomic signatures on modern molluscs and corals from Red Sea coast, southern Saudi Arabia

Bioeroded gastropod, bivalve and coral specimens (n = 570) were collected from the Jazan area, Saudi Red Sea coast, from which 22 ichnospecies of 8 ichnogenera were identified and illustrated. These traces were produced by clionid sponges (Entobia geometrica, E. ovula, E. cf. goniodes, E. cretacea, E. laquea, E. cf. paradoxa and E. isp.), duraphagous drillers (Oichnus ovalis, O. paraboloides, O. simplex and O. isp.), endolithic bivalves (Gastrochaenolites cf. dijugus, G. lapidicus, G. torpedo and G. isp.), polychaete annelids (Caulostrepsis taeniola, C. isp., Maeandropolydora sulcans, M. isp. and ?Trypanites isp.), acorn barnacles (Rogerella isp.), and vermetid gastropods (Renichnus isp.). The seashells act as hard substrate for colonization by serpulid worm, bivalves, bryozoans, and barnacles. Ichnogenus Entobia was most abundant (56.1%), followed by Gastrochaenolites (25.4%), Caulostrepsis (5.3%), Trypanites (4.2%), Maeandropolydora (3.2%), Oichnus (2.8%), Renichnus (1.9%), and Rogerella (1.0%). Oichnus occurred on the thin-shelled and smooth molluscs, while most Gastrochaenolites borings were found in the larger and thicker seashells as a suitable substrate for the settlement of polychaetes, lithophages, naticids, mytilids, and vermetids. Presence of annelid traces among radial ribs and at the siphonal areas of bivalves is indicative of nutrient capturing from water flow during the lifetime of these bivalves, within a shallow, high energy marine environment, where disarticulation, fragmentation, and abrasion of the seashells were abundantly observed. (C)& nbsp;2021 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights reserved.

Automated summary

This study examined bioeroded gastropod, bivalve, and coral specimens from the Jazan area along the Saudi Red Sea coast, identifying 22 ichnospecies of 8 ichnogenera. The traces were produced by various organisms such as sponges, drillers, bivalves, polychaete annelids, barnacles, and gastropods. The distribution and characteristics of these traces provide insights into the bioerosion processes in shallow, high energy marine environments.