The first leech body fossil predates estimated hirudinidan origins by 200 million years.

ABSTRACT: Clitellata is a major annelid clade comprising oligochaetes (e.g., earthworms) and hirudineans (e.g., leeches). Due to their scant fossil record, the origins of clitellates, particularly Hirudinea, are poorly known. Here, we describe the first leech body fossil, Macromyzon siluricus, gen. et sp. nov., from the Brandon Bridge Formation (Waukesha Lagerstätte). This fossil, which is preserved in exceptional detail, possesses several hirudinean soft-tissue synapomorphies-including a large sucker at the posterior end and sub-divided segments-and phylogenetic analyses resolve Macromyzon siluricus as a stem leech. Its age, 437.5-436.5 Ma, is consistent with early age estimates for the origin of clitellates, and predates molecular-clock-based estimates of hirudinidan or

SUBMITTER: de Carle D 

PROVIDER: S-EPMC12495953 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature