Tarnimidae

Tarnimidae is a taxonomic family of extinct arthropods known from fossil remains. Descriptions in the paleontological literature have treated Tarnimidae as a distinct family, though the exact placement within the arthropod tree has been debated. Some studies place Tarnimidae within a broader early-diverging clade of arthropods, while others regard it as a stem lineage outside the principal crown groups.

Morphological diagnoses of Tarnimidae emphasize a characteristic arrangement of frontal plates and limb joints, along with particular patterns of segmentation observed in fossil exoskeletons. However, diagnoses vary across revisions as new specimens are discovered or re-examined.

The family is represented by multiple genera described from fossil sites in several regions. The material is predominantly impressions of carapaces and appendages, with limited soft-tissue preservation, which constrains the completeness of interpretations.

The known temporal range of Tarnimidae spans a broad interval in the fossil record, indicating a long-standing presence before extinction. The exact age span and paleobiogeography remain subjects of ongoing research, with new finds potentially expanding the known diversity.

Taxonomic status is subject to change as methods such as cladistic analyses and comparative anatomy evolve. Tarnimidae serves as a case study in how fossil data can support competing hypotheses about early arthropod evolution.

See also: prehistoric arthropod families; taxonomy of early arthropods.