Tribe Liadoxyelini Rasnitsyn, 1966
Type genus
Liadoxyela Martynov, 1937.
This tribe was proposed for four genera (Liadoxyela Martynov, 1937, Kirghizoxyela Rasnitsyn, 1966, Anomoxyela Rasnitsyn, 1966, and Lydoxyela Rasnitsyn, 1966) and five species from Jurassic and Early Cretaceous of Siberia and Central Asia, based on a set of diagnostic characters including short 1m-cu (about half as long as 3-Cu) as distinguishing it from Xyelini Newman, 1834, the only other tribe in subfamily Xyelinae (Rasnitsyn 1966). The next revision of Xyelidae and Symphyta in general (Rasnitsyn 1969) added another diagnostic feature, 1-Rs not longer than 1-M. One more genus (Orthoxyela Rasnitsyn, 1983) and two species from the Jurassic of Siberia have been added to the tribe since (Rasnitsyn 1983). Much later three further genera (Platyxyela Wang et al., 2012, Cathayxyela Wang et al., 2014, Aequixyela Wang et al., 2014), each with one species from the Middle Jurassic of China, have been added to the tribe, even though not without confusion (Wang et al. 2012, 2014). The first genus was described in Macroxyelinae Ashmead, 1898 but later listed under Liadoxyelini Rasnitsyn, 1966 (Wang et al. 2014: table 1). Judging from their descriptions and the table 1, Cathayxyela and Aequixyela were equally described as members of Liadoxyelini, but this was under the title Xyelini which we consider a lapsus calami. We agree with the interpretation of Platyxyela and Cathayxyela as members of Liadoxyelini. However, Aequixyela differs from other Liadoxyelini considerably in having 1-Rs scarcely longer than 1-M, 1m-cu distinctly longer than half 3-Cu, pterostigma distinctly inflated (often in Xyelini but never in Liadoxyelini), and unlike all Xyelidae, ovipositor very short and narrow. Unusual is also the very short antennal flagellum, only comparable with that in living Macroxyelini Ashmead, 1898. The position of the latter genus needs special consideration: for the moment we consider it as Xyelinae incertae tribus.