The inaccuracy of the "protura-sister" hypothesis: Reassessing early hexapod phylogeny

Tsukuba, Japan—Hexapods, which make up 75% of all animal species, have been a focus of evolutionary debate for over a century. No consensus has been reached on the phylogenetic relationships among the four earliest lineages: Protura, Collembola, Diplura, and Insecta, the latter including all hexapods except the first three groups. To clarify these relationships, researchers have conducted large-scale molecular phylogenetic analyses using extensive gene sequence datasets. These studies have supported the "Ellipura" hypothesis, which proposes the grouping [Ellipura (= Protura + Collembola) + (Diplura + Insecta)], as the most widely accepted theory.

However, the alternative "Protura-sister" hypothesis (Protura + [(Collembola + Diplura) + Insecta]) has emerged based on molecular phylogenetic analysis and garnered substantial attention. However, by examining the non-nucleotide sequence data used to support this hypothesis, researchers identified critical errors resulting from misinterpretation and insufficient analysis.

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This work was supported by the JSPS (Japan Society for the Promotion of Science) KAKENHI: Grant-in-Aid for Scientific Research C, 19K06821 to RM.

_{Original Paper}

Title of original paper:
Embryology cannot establish the "Protura-sister"

Journal:
Proceedings of the National Academy of Sciences of the United States of America

DOI:
10.1073/pnas.2423813122

_{Correspondence}

Visiting Researcher MACHIDA, Ryuichiro
Sugadaira Research Station, Mountain Science Center, University of Tsukuba

Associate Professor FUKUI, Makiko
Graduate School of Science and Engineering, Ehime University

Researcher TOMIZUKA, Shigekazu
Echigo-Matsunoyama Museum of Natural Science "Kyororo"

Assistant Professor IKEDA, Yatsukaho
Faculty of Medicine, Oita University

Assistant Professor MASUMOTO, Mika
College of Liberal Arts and Sciences, Kitasato University

_{Related Link}

Sugadaira Research Station, Mountain Science Center, University of Tsukuba