The first healed injury in a hyolith operculum

Area of Science:

• Paleontology
• Marine Biology
• Evolutionary Biology

Background:

• The Barrandian area is renowned for its fossil-rich Palaeozoic sediments, including abundant marine fauna like hyoliths.
• Malformed invertebrates (trilobites, cephalopods, gastropods) are documented, but malformed hyoliths have not been previously recorded.
• Hyoliths are extinct Palaeozoic animals characterized by a calcium carbonate shell (conch) and a cap (operculum).

Purpose of the Study:

• To describe the first instance of regeneration in a hyolith operculum.
• To investigate evidence of non-lethal predatory attacks on hyoliths.
• To identify potential predators responsible for the damage.

Main Methods:

• Detailed morphological examination of an Ordovician hyolith operculum specimen.
• Analysis of fossil evidence to identify signs of repair and regeneration.
• Comparative analysis with known predatory behaviors on marine invertebrates.

Main Results:

• An operculum of the Ordovician hyolith Elegantilites custos exhibits clear signs of regeneration.
• The damage pattern suggests a failed durophagous predatory attack.
• This represents the first documented case of regeneration in a hyolith operculum.

Conclusions:

• Regeneration was a capability present in hyoliths, indicating complex biological responses to injury.
• Failed predatory attacks by epibenthic/infaunal predators, possibly echinoderms like ophiuroids, are implicated.
• This finding expands our understanding of hyolith paleoecology and survival strategies.