Paragloborilus sp.

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 : 389-390

Paragloborilus sp.

Fig. 51I, J.

Material.—Two internal moulds, SMNH X5857, 5858, from samples K2/21 (section 3, Fig. 3) and K1a/80 (section 2, Fig. 1), respectively, from the Medvezhya Formation, western Anabar Uplift, Siberian Platform, Russia. Correlated with the upper Fortunian Stage.

Description.—Conch short, curved in one plane, with circular cross-section and bulbous protoconch separated by a shallow circular constriction (as replicated on smooth internal moulds).

Remarks.—The fossil is similar in general shape to Paragloborilus subglobosus , but is represented by smooth internal moulds. By contrast, P. subglobosus typically shows faint transverse growth lines on the inner molds. However, the syntypes of this species also include relatively smooth steinkerns (see Steiner et al. 2007: fig. 6L, M). Paragloborilus subglobosus is described as having a broadly oval (e.g., Parkhaev and Demidenko 2010) or circular (Qian and Bengtson 1989) transverse cross-section. Salanytheca Missarzhevsky, 1981 , was synonymized with Paragloborilus by Qian and Bengtson (1989). Except for one species, Paragloborilus papillaris (Missarzhevsky, 1981) with prominent transverse ribs from the lower Cambrian of the Siberian Platform and western Mongolia, other known species of Paragloborilus are only known from the middle Meishucunian Stage of South China (see Parkhaev and Demidenko 2010; but note statement in Yang et al. 2014 on an erroneous report of Paragloborilus sp.

from the Fortunian Anabarites trisulcatus – Protohertzina anabarica Assemblage Zone ).