Dysagrionites Archibald and Cannings

Archibald, S. Bruce & Cannings, Robert A., 2024, Three new Odonata species (cf. Cephalozygoptera and cf. Dysagrionidae) from the early Eocene Okanagan Highlands of British Columbia, Canada, and Washington, United States of America, The Canadian Entomologist (e 35) 156, pp. 1-9 : 2-3

collective genus Dysagrionites Archibald and Cannings

Figure 1

Remarks. Archibald and Cannings (Archibald et al. 2021) created the genus-level collective taxon Dysagrionites to function as a holding bin for fossil odonates referrable to the Dysagrioninae ( Cephalozygoptera , Dysagrionidae ) that can be clearly separated from species of that subfamily but whose nominal generic affinity is unclear by the preservation and completeness of their currently known specimens. Collective taxa are regulated by the International Commission on Zoological Nomenclature (International Trust for Zoological Nomenclature 1999, for example, articles 42.2.1 and 42.3.1).

Archibald et al. (2021) referred three species to the parataxon: Dysagrionites delinei Archibald and Cannings and Dysagrionites sp. A and Dysagrionites sp. B . They erred, however, in that the parataxon definition required that those species are established as members of the Dysagrioninae , and although this strongly appears to be the case, these fragmentary fossils lack enough of the character states that, in combination, firmly place them in the family and, therefore, in this subfamily. Simonsen et al. (2024) subsequently established a diagnosis of Dysagrionidae using wings alone; however, known specimens of Dysagrionites species still lack sufficient morphology for confirmation. We emend the collective taxon definition by adding “or tentatively so”: This genus-level collective group name is proposed for any fossil species referable to the Dysagrioninae , or tentatively so, that can be clearly defined at the species level, separating them from other species of the subfamily, but whose orthotaxon generic affinity is unclear by the incomplete preservation of its currently known specimens. Dysagrionites then includes these three species and D. allenbyensis , described here.

If our assumption that D. allenbyensis is a dysagrionid is correct, it belongs to the Dysagrioninae , as the origin of its RP3–4 is about two-thirds the distance between the arculus and nodus and IR2 originates at the subnodus [Petrolestinae: RP3–4 originates more proximally, closer to, or at, the point midway between the arculus and subnodus, and IR2 originates close to, or on, RP3–4; subfamily diagnoses were summarised by Archibald et al. 2021].

Allenbya holmesae Archibald and Cannings is the only previously known non-anisopteran odonate from the Allenby Formation. It is also tentatively treated as a dysagrionid and cephalozygopteran but is distinct enough to be assigned to a nominal genus ( Archibald and Cannings 2022). It is also a fragmentary wing, but in this case, the distal portion is preserved. It is distinct from D. allenbyensis ; for example, IR1 is zigzagged, and the postnodal and postsubnodal crossveins are not aligned.

Figures

Figure 1. Dysagrionites allenbyensis n. sp. A, holotype BBM-P000020: A, photograph of the part (A-side); B, drawing from the part and counterpart. Both to scale; the scalebar is 5 mm.