Small carbonaceous fossil

This category of fossils has traditionally included robust or thick-walled entities such as plant spores, acritarchs and chitinozoa, but the term 'SCFs' is usually applied to more fragile remnants of animals that can only be extracted through a delicate maceration technique.

[5] Traditional palynological methods are designed for extracting fossilized plant spores and other resistant organic microfossils such as acritarchs and chitinozoa.

In particular, this technique has been applied to sediments deposited during the Cambrian Period, since there is great interest in tracking how soft-bodied animals evolved during this time interval.

[1][6][7][4] Animal SCFs extracted from Cambrian sediments include the minute scales of priapulid worms,[7] Wiwaxia sclerites,[8] and arthropod feeding parts,[6] for example.

[1] As such, SCFs can help to fill in some of the details of the fossil record outside the rare Lagerstätten sites: for instance, highlighting the rapid nature of the Cambrian explosion.

A fragment of Silurian arthropod cuticle with attached setae, extracted by delicate acid maceration
Scanning electron micrograph of a late Silurian chitinozoan, an enigmatic Palaeozoic SCF that can be recovered by the standard palynological technique. Scale bar: 50 μm