The biological species concept cannot be applied to fossils. which alternative to identifying species would be most useful for classifying fossil organism?

Fossils can be classified by their morphology (how they look), ethologically (how they acted), and toponomically (where they are in the substrate layers) to produce phylogenetic trees. However, more recent advances in genetic technology allow us to extract DNA from more recent fossils that have not had too much breakdown of the DNA, and we can much more accurately classify species from that information, and also provide much more accurate phylogenetic analysis.