Skip to Main content Skip to Navigation
Conference papers

Get across the wood: preservation of Cretaceous soft-bodied xylophagous mollusks (Bivalva, Teredinidae)

Abstract : Teredinidae are obligate wood-boring bivalves displaying a particularly specialized anatomy with calcareous hemispherical valves highly reduced in size. These xylophagous bivalves are able to digest the cellulose which is excavated along drilling thanks to endosymbiotic bacteria. Additionally to the valves, the animal secrets terminal aragonitic pallets and also calcitic linings at some point of its body, but the majority of its anatomy is made of soft-tissues. Therefore, fossil teredinids usually consist of isolated valves and pallets in situ and boring structures well-known as ichnotaxa (Teredolites) which are more or less preserved with calcitic linings and/or infilled by sediments. They are known from the Jurassic to the Cenozoic with their oldest occurrence in Lias (Pliensbachien). Here, we report exceptionally preserved teredinid bivalves from the Early Cretaceous of the Envigne Valley (Vienne, France) with exposed fossilized soft parts (foot) of the animals which are frozen by silicification. The Envigne Valley consists of a very prolific deposit for paleobotanics, yielding a diversity of conifers, angiosperms, cycadaceae and ferns showing an especially high cellular definition in woods. This special apparent preservation of the mollusks pushed us to investigate the inner content and organisation of the two inhabited woody specimens. After analyzing the wood nature of the sunken substrate, the specimens were scanned using computed tomography (CT-scan of Poitiers, France). Thus, we could document the preservation, the systematics and ecological aspects of these xylophagous bivalves thanks to the 3D-reconstruction. The identification, which is mostly based on the shells for fossil representatives, has been attempted on the basis of especially thin elements of the shells which were found inside the wood and usually unpreserved. The total number of borings and co-occurrences of living animals were quantified, and the drilling orientations in wood pieces were compared. All these elements allow documenting the ecology and nature of some of these curious soft bivalves through a snapshot on their 100 Ma-old petrified microenvironment.
Complete list of metadata

https://hal-mnhn.archives-ouvertes.fr/mnhn-03226147
Contributor : Anais Boura <>
Submitted on : Friday, May 14, 2021 - 10:02:56 AM
Last modification on : Sunday, May 16, 2021 - 3:12:56 AM

Identifiers

  • HAL Id : mnhn-03226147, version 1

Citation

Ninon Robin, Anais Boura, Jean-Marie Boiteau, Xavier Valentin. Get across the wood: preservation of Cretaceous soft-bodied xylophagous mollusks (Bivalva, Teredinidae). 2nd International Meeting for Early Researchers in Paleontology, May 2017, Sigri, Greece. ⟨mnhn-03226147⟩

Share

Metrics

Record views

28