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Updated: Sep 25, 2026

A Concoction Pipeline for Generating Molecular Operational Taxonomic Units (MOTUs) Among Riparian and Aquatic Beetles
Published on: July 11, 2025
Structural rRNA characters support monophyly of raptorial limbs and paraphyly of limb specialization in water fleas
Timothy D Swain1, Derek J Taylor
1Department of Biological Sciences, Florida State University, Tallahassee, FL 32306, USA.
Abstract:
The evolutionary success of arthropods has been attributed partly to the diversity of their limb morphologies. Large morphological diversity and increased specialization are observed in water flea (Cladocera) limbs, but it is unclear whether the increased limb specialization in different cladoceran orders is the result of shared ancestry or parallel evolution. We inferred a robust among-order cladoceran phylogeny using small-subunit and large-subunit rRNA nuclear gene sequences, signature sequence regions, novel stem-loops and secondary structure morphometrics to assess the phylogenetic distribution of limb specialization. The sequence-based and structural rRNA morphometric phylogenies were congruent and suggested monophyly of orders with raptorial limbs, but paraphyly of orders with reduced numbers of specialized limbs. These results highlight the utility of complex molecular structural characters in resolving ancient rapid radiations.
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