Morphological variation in Guimaraesiella Eichler, 1949 (Phthiraptera: Ischnocera: Philopteridae: Brueelia-complex)

Guimaraesiella Eichler, 1949, is the most morphologically heterogeneous genus in the Brueelia-complex. Interspecific differences in genitalia, head shape, extent of dorsal preantennal suture, and abdominal chaetotaxy can be extensive. Moreover, Guimaraesiella is known from a vast range of host families, and are likely to occur on most passeriform families across the world [1, 2]. Lice that are genetically and morphologically indistinguishable are known to parasitize several host species, including hosts from different host families [1]. Many of the known Guimaraesiella, and most of the roughly 150 undescribed species we have examined, are morphologically similar to the type species. However, molecular data indicate that some morphologically distinct species, such as Guimaraesiella menuraelyrae (Coinde, 1859), are nested inside this core group of Guimaraesiella [1]. Delimitation of groups within this genus is therefore problematic, especially as the undescribed diversity is larger than the described diversity. Several genera have previously been proposed for smaller groups within this genus, but these have not been based on an extensive survey of character variation within Guimaraesiella or the Brueelia-complex. The recently erected genera Callaenirmus Mey, 2017, Mohoaticus Mey, 2017, and Philemoniellus Mey, 2017, are all synonymous with Guimaraesiella. We here outline 14 species groups within Guimaraesiella; some of these, such as the proposed genus Mohoaticus, may warrant recognition as subgenera in the future. Species groups proposed here are based on morphology for aid of identification, and do not constitute positive statements of monophyly. Some known species are too poorly described to be placed in any group presently. References: [1] Bush, S.E., Weckstein, J.D., Gustafsson, D.R., Allen, J., DiBlasi, E., Shreve, S.M., Boldt, R., Skeen, H.R., & Johnson, K.P. (2016) Unlocking the black box of feather louse diversity: A molecular phylogeny of the hyper-diverse genus Brueelia. Molecular Phylogenetics and Evolution 94, 737–751. [2] Gustafsson, D.R. & Bush, S.E. (2017) Morphological revision of the hyperdiverse Brueelia-complex (Insecta: Phthiraptera: Ischnocera: Philopteridae) with new taxa, checklists and generic key. Zootaxa 4313, 1–443.

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