Itaxia Korshunova 2017

Itaxia Korshunova et al., 2017, reinstated (Figs 1, 2, 13; Table 5) Korshunova et al. 2017a: 39–40. Type species: Coryphella falklandica Eliot, 1907. Diagnosis: Bodymoderatelywide.Notaledgepresent,continuous. Cerata in continuous rows. Rhinophores wrinkled. Anterior foot corners present. Central teeth with non-compressed wide cusp and distinct denticles. Lateral teeth denticulated without attenuated process basally. Receptaculum seminis not evident. Vas deferens very short, expands into a broad penial sheath, prostate indistinct. Penis broad, lobe-shaped. Species included: Itaxia falklandica (Eliot, 1907) comb. nov .. Detailed morphological data in Korshunova et al. (2017a). Remarks: The genus Itaxia inhabits exclusively the southern parts of South America and possibly some more distant localities in the Southern Ocean (which may represent, in turn, as yet undetected hidden diversity of Itaxia; Odhner 1944, Marcus 1959). According to the molecular phylogenetic data of all the phylogenetic analyses performed so far (Korshunova et al. 2017a, present study; Figs 1, 13), it is the basal-most coryphellid taxon. Morphologically the characters of Itaxia rather mosaically combine the ancestral continuous notal edge, but at the same time presents an extremely reduced vas deferens and also possesses a very strong cusp of the central teeth (Korshunova et al. 2017a). Thus, Itaxia therefore very well demonstrates multilevel fine-scale diversity in its morphology and molecular phylogenetic data. The genus Itaxia was named after the word itax meaning ‘south’ in the currently extinct Yagán language from the southern tip of South America [but in 2017, when the Korshunova et al. (2017a) monograph with the name Itaxia was published, the last native Yagán speaker was still alive], to respect these indigenous southernmost people in the world and their ancestral heritage. Likewise the genus Itaxia represents one of earliest offshoots of the basal radiation of the family Coryphellidae (Figs 1, 13) and keeps some of the ancestral features of the common ancestor of all Coryphellidae. Comparison of the genus Itaxia with all valid, currentlyincluded Coryphellidae genera is presented in Table 5.