Increasing species sampling in chelicerate genomic-scale datasets provides support for monophyly of Acari and Arachnida

Jesus Lozano-Fernandez, Alastair Tanner, Mattia Giacomelli, Robert Carton, Jakob Vinther, Gregory D. Edgecombe, Davide Pisani*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

10 Citations (Scopus)
192 Downloads (Pure)


Chelicerates are a diverse group of arthropods, represented by such forms as predatory spiders and scorpions, parasitic ticks, humic detritivores, and marine sea spiders (pycnogonids) and horseshoe crabs. Conflicting phylogenetic relationships have been proposed for chelicerates based on both morphological and molecular data, the latter usually not recovering arachnids as a clade and instead finding horseshoe crabs nested inside terrestrial Arachnida. Here, using genomic-scale datasets and analyses optimised for countering systematic error, we find strong support for monophyletic Acari (ticks and mites), which when considered as a single group represent the most biodiverse chelicerate lineage. In addition, our analysis recovers marine forms (sea spiders and horseshoe crabs) as the successive sister groups of a monophyletic lineage of terrestrial arachnids, suggesting a single colonisation of land within Chelicerata and the absence of wholly secondarily marine arachnid orders.

Original languageEnglish
Article number2295
JournalNature Communications
Issue number1
Publication statusPublished - 24 May 2019



  • Acari/genetics
  • Animals
  • Aquatic Organisms/genetics
  • Datasets as Topic
  • Evolution, Molecular
  • Genome
  • Horseshoe Crabs/genetics
  • Phylogeny
  • Spiders/genetics

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