Khairkhania cf. rotata Missarzhevsky, 1981

Kouchinsky, Artem, Bengtson, Stefan, Landing, Ed, Steiner, Michael, Vendrasco, Michael & Ziegler, Karen, 2017, Terreneuvian stratigraphy and faunas from the Anabar Uplift, Siberia, Acta Palaeontologica Polonica 62 (2), pp. 311-440 : 353-355

publication ID

https://doi.org/ 10.4202/app.00289.2016

persistent identifier

https://treatment.plazi.org/id/03AD87A8-FFB1-6D0B-FCCF-FA0B640D8214

treatment provided by

Felipe

scientific name

Khairkhania cf. rotata Missarzhevsky, 1981
status

 

Khairkhania cf. rotata Missarzhevsky, 1981 View in CoL

Fig. 25D View Fig .

Material.—Single phosphatized internal mould SMNH Mo182294 and seven fragments of internal moulds of presumably the same species from sample 3/0 (section 3, Fig. 3), basal Medvezhya Formation (see SOM 1), western Anabar Uplift, Siberian Platform, Russia. Correlated with upper Fortunian Stage.

Description.—Planispiral shell, relatively tightly coiled through ca. 1 revolution, with blunt rounded apex and indistinctly separated protoconch. Cross-section broadly oval.

Remarks.— Khairkhania rotata from western Mongolia and forms of this species described by Parkhaev (2006, 2007b, 2008) from the northwestern flanks of the Anabar Uplift are generally similar but smaller (ca. 75% in size) than the material illustrated herein as Khairkhania cf. rotata ( Fig. View Fig

25D). Khairkhania sp. from the same sample are either fragmentary or open coiled with up to 1/2 revolution ( Fig. 25E, F View Fig ). They may represent a different species, morphological variants, or younger growth stages of the same species. Khairkhania cf. evoluta (see below) is represented by high, cyrtoconic, relatively more laterally compressed internal moulds with smaller protoconchs.

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