Phtuariinae Burks and Heraty incertae sedis ( Chalcidoidea)

Phtuariinae Burks et al., 2015 in Burks et al. 2015: 593–596. Type genus: Phtuaria Burks and Heraty by original monotypy.

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Phtuaria incertae sedis Burks & Heraty is a fossil genus of Chalcidoidea recovered from middle Eocene Baltic amber (41.3–47.8 mya) (Burks et al. 2015, figs 1–4). Placement of Phtuaria remains a contentious topic because of its unique combination of morphological character states, allying the genus with a bizarre assemblage of chalcidoid families, including Aphelinidae, Baeomorphidae, Calesidae, Eulophidae, Idioporidae, Mymaridae, Pirenidae, Tetracampidae, and Trichogrammatidae (Burks et al. 2015) . The authors rejected the placement of Phtuaria in all families except Aphelinidae, in which they include the genus because it ‘possesses a mixture of features that are frequently used to characterize [the aphelinid] subfamilies’. However, in the same publication, inclusion within each subfamily is systematically rejected as the correct placement for Phtuaria . The authors ultimately choose to place the genus in its own subfamily Phtuariinae Burks et al. 2015 . After the removal of Cales from Aphelinidae (Burks et al. 2022), there were no longer any known Aphelinidae with a straight fore tibial spur, further weakening the placement of Phtuaria in the family.

Morphological phylogenetic analyses have not resolved the placement of Phtuaria . Burks et al. (2015) explored adding Phtuaria to the morphological matrix from Heraty et al. (2013). The results were variable between analysis types, with Phtuaria recovered (1) in a clade alongside Mongolocampinae ( Tetracampidae), Baeomorphidae and Mymaridae; (2) as the sister to all Chalcidoidea excluding Mymaridae and Baeomorphidae; or (3) within the Aphelinidae as sister to Aphelinini + Eretmocerinae + Coccophaginae . Ongoing analyses are exploring the placement of Phtuaria and recover it either within Aphelinidae or associated with Signiphoridae and Azotidae . Until we uncover stronger evidence to support the placement of Phtuaria, we place Phtuariinae as incertae sedis within Chalcidoidea .