Cretaceous amniote integuments recorded through a taphonomic process unique to resins

Area of Science:

• Paleontology
• Taphonomy
• Paleobiology

Background:

• Fossil integument records, particularly Mesozoic ones, are crucial for understanding vertebrate evolution.
• Amber inclusions provide exceptional preservation of biological material.
• Existing taphonomic models primarily focus on entrapment and embedding in resin.

Purpose of the Study:

• To describe and analyze two Spanish Cretaceous amber specimens with unique integument preservation.
• To introduce and define a novel biostratinomic process termed "pull off vestiture."
• To re-evaluate existing fossil records based on this new taphonomic understanding.

Main Methods:

• Microscopic examination of Cretaceous amber specimens containing feather and hair remains.
• Taphonomic analysis of the preservation context, including resin interaction and surface features.
• Actualistic experiments using sticky traps in Madagascar to observe resin interactions with modern integuments.

Main Results:

• Discovery of avian dinosaur feather remains preserved through "pull off vestiture" from direct contact with resin.
• Identification of exceptionally preserved mammalian hair strands, forming a tuft, also preserved via this process.
• Demonstration that "pull off vestiture" is distinct from typical resin entrapment, involving surface adhesion and resin hardening.

Conclusions:

• The "pull off vestiture" process offers a new mechanism for the exceptional preservation of integuments in fossil resins.
• This process provides critical insights into the taphonomy and paleoecology of vertebrate integument preservation during the Cretaceous.
• Reinterpretation of literature records in light of "pull off vestiture" enhances understanding of fossil origins.