CLADOENDESIS OF EPHEMEROPTERA
(Panephemeroptera Euephemeroptera Euplectoptera INCERTAE SEDIS)
Nomen hierarchicum: Mesogenesia/g1 [g:1977] (incl. Archaeobehningia)
In circumscription fits:
— Mesogenesia/g1: Kluge 2004: 356
Nominal taxon included: Archaeobehningia/g [g:1977]
References. Tshernova 1977 (Mesogenesia, Archaeobehningia): ; — Kluge 2004:
Autapomorphy of Mesogenesia/g1.
(1) Larval fore leg is specialized as grasping (but not burrowing, as it was originally described): it is enlarged (at least larger than middle one), directed forward with knee directed dorsally and claw directed ventrally; its coxa is elongate; femur is widened, with dense setation on inner side. Unlike burrowing legs of Fossoriae, tibia is not widened (in the original description of petersae [M.] femur was taken for tibia, and boundary between tibia and tarsus was overlooked). In petersae [M.] fore leg looks as having two claws, possibly because of a pointed spine-like inner-apical angle of tarsus which is similar to the true claw, but a little shorter.
Character of Mesogenesia/g1 of unclear phylogenetic status.
(2) Larval middle leg is the smallest, and hind leg the largest; in the both specimens examined (fossils pressed laterally) middle legs are directed forward like fore legs, and hind legs are directed backward. The same in Furcatergaliae-Fossoriae.
Plesiomorphy of Mesogenesia/g1. Unlike recent Furcatergaliae, caudalii retain primary swimming setation on median sides of cerci and lateral sides of paracercus, and have no secondary swimming setae on lateral sides of cerci (only basal parts of cerci and paracercus are preserved in holotype of petersae [M.], while caudalii of edmundsi [A.] are unknown).
Age. Jurassic (Siberia).
Nominal species in Mesogenesia/g1:
edmundsi Tshernova 1977 [Archaeobehningia] Pal.Inst.
petersae Tshernova 1977 [Mesogenesia] Pal.Inst.
other Euplectoptera INCERTAE SEDIS