Nuttalliellidae in Burmese amber: implications for tick evolution.

Area of Science:

• Paleontology
• Arachnology
• Evolutionary Biology

Background:

• Ticks are classified into three extant families: Argasidae, Ixodidae, and Nuttalliellidae, with Nuttalliellidae having one species in the Afrotropics.
• Fossil evidence of Deinocrotonidae in Burmese and Iberian amber suggests a broader ancient distribution for this lineage.
• The limited distribution of extant Nuttalliella namaqua raises questions about the historical geographic range and origins of ticks.

Purpose of the Study:

• To describe new tick fossils from mid-Cretaceous Burmese amber.
• To re-evaluate the taxonomic placement of Deinocroton within tick families.
• To infer the paleobiogeography and evolutionary history of the Nuttalliellidae family.

Main Methods:

• Description and analysis of eight tick fossils from Burmese amber, including new species and a new genus.
• Comparative morphological analysis of fossil taxa with extant tick families.
• Paleogeographic reconstruction based on fossil distribution and tectonic history.

Main Results:

• Discovery of two new Deinocroton species, five new Nuttalliella species, and a new genus, Legionaris, from Burmese amber.
• Reclassification of Deinocroton as part of the Nuttalliellidae family, expanding it to three genera: Deinocroton, Legionaris, and Nuttalliella.
• Evidence suggests Nuttalliella had a wide distribution across Africa, Antarctica, and Australia during the Cretaceous.

Conclusions:

• The Nuttalliellidae family likely originated with a much wider distribution than its current Afrotropical range.
• The findings support potential undiscovered extant Nuttalliella species in Australia.
• An Afrotropical origin for ticks remains a plausible hypothesis, though broader ancient distributions are now evident.