page_title: Usomyrma
section_title: Classification and taxonomy
hierarchical_section_title: Usomyrma / Classification and taxonomy
caption_attribution_description: English: Fig. 4. Dolichoderine ant Leptomyrmula maravignae (Emery, 1891), the holotype male, from the Sicilian Amber, body in lateral view (after Emery 1891).
context_page_description: Usomyrma is an extinct genus of ant in the formicid subfamily Dolichoderinae. The genus contains a single described species, Usomyrma mirabilis, that is known from two Middle Eocene fossils which were found in Scandinavian amber in Denmark.
context_section_description: Based on interpretation of the wing venation in the U. mirabilis, Dlussky et al suggested the genus was a member of the Dolichoderinae tribe Leptomyrmecini along with the living Leptomyrmex "spider ants" and the Sicilian amber genus Leptomyrmula. They noted that an unsubscribed male Leptomyrmex male in Dominican amber was distinct enough from the Dominican amber species Leptomyrmex neotropicus to possibly warrant being placed into a new genus, but a full description of the male had not taken place as of 2014. Dlussky et al thought U. mirabilis represented an ancestral wing venation for the tribe, with a progression in vein reduction being present in Leptomyrmula. The Leptomyrmex was treated as a descendant genus of the ancestral form Usomyrma in the classification suggested by Dlussky et al.
  A 2016 study showed the central cell reduction, on which placement of the genus was based, was shown to be derived several times in the subfamily and not specific to the tribe Leptomyrmecini. The study included the description of the species Leptomyrmex relictus from Brazil, and study of the micro-Leptomyrmex clade species. While the macro-Leptomyrmex species have a very reduced wing venation, the micro-Leptomyrmex clade is nested inside the macro species but have retained much of the vein structure unlike the macro-species. This mosaic of both retained wing venation and reduced wing venation within Leptomyrmex contradicted the gradual vein loss hypothesis that was proposed for an evolutionary grade of Usomyrma - Leptomyrmula - Leptomyrmex. As such both Usomyrma and Leptomyrmula were moved to being placed in Dolichoderinae without tribal placement.
caption: Drawing of the Leptomyrmula maravignae male
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