Ichnofossil:
A trace fossil, also called an ichnofossil (/ˈɪknoʊˌfɒsɪl/; from Ancient Greek ἴχνος (íkhnos) ‘trace, track‘), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of parts of organisms’ bodies, usually altered by later chemical activity or by mineralization. The study of such trace fossils is ichnology – the work of ichnologists. [Wikipedia]
Noted in “Ancient Bees Found Nested Inside Fossilized Bone — A Behavior Never Seen Before,” Anastasia Scott, Discover:
There is no evidence that the insects drilled into or reshaped the fossils. Instead, they made use of hollow spaces that already existed and closely matched the size and geometry of their nests. What remains is not the bees themselves, but physical traces of their behavior — an ichnofossil preserved within the remains of much larger animals.
