Yochelcionella Runnegar and Pojeta, 1974

Skovsted, Christian B. & Peel, John S., 2007, Small shelly fossils from the argillaceous facies of the Lower Cambrian Forteau Formation of western Newfoundland, Acta Palaeontologica Polonica 52 (4), pp. 729-748 : 736

Genus Yochelcionella Runnegar and Pojeta, 1974 Yochelcionella cf. chinensis Pei, 1985

Fig. 4D.

Type species: Yochelcionella cyrano Runnegar and Pojeta, 1974 .

Material.—NFM−685 and hundreds of additional specimens from samples ICS 1421, ICS 1518, and JSP1982−01.

Discussion.—Internal moulds of Yochelcionella with an erect profile in lateral view, elongated oval cross−section, apex slightly curved towards the prominent snorkel and an ornamentation of fine co−marginal ribs are reminiscent of Yochelcionella chinensis from the Early Cambrian Xinji Formation of Henan, North China. The specimens from western Labrador differ from the type specimen of Y. chinensis ( Pei 1985: pl. 1) in the slightly larger protoconch, the finer and more numerous co−marginal ribs and in the shorter length of the snorkel. Two specimens from South Australia were assigned to Y. chinensis by Runnegar (see Bengtson et al. 1990). Similar fossils were described from New York State by Landing and Bartowski (1996) and from Quebec by Landing et al. (2002) as Yochelcionella sp.

Yochelcionella cf. chinensis differ from the co−occurring Yochelcionella americana in the less strongly coiled apex, the wider aperture and the fine co−marginal ribs. Although Y. americana may be more widely distributed in eastern Laurentia (see below), Y. cf. chinensis vastly outnumbers Y. americana in the acid residues from western Newfoundland.

Yochelcionella americana Runnegar and Pojeta, 1980 Fig. 4E.

1980 Yochelcionella americana sp. nov.; Runnegar and Pojeta 1980: 636, fig. 1.

1987 Yochelcionella americana Runnegar and Pojeta, 1980 ; Peel 1987: 2329, fig. 1.

1991 Yochelcionella americana Runnegar and Pojeta, 1980 ; Peel 1991: fig. 27.

Holotype: USMN 274001. Internal mould from the Lower Cambrian

Vintage Dolomite, Thomasville, Pennsylvania.

Material.—NRM−686 and 50 additional specimens from sample JSP1982−01.

Discussion.—Laterally compressed internal moulds with a strongly coiled apex almost reaching the prominent snorkel and with low co−marginal ribs on the lateral sides are indistinguishable form Yochelcionella americana from the Lower Cambrian of Pennsylvania ( Runnegar and Pojeta 1980). Specimens of Y. americana described by Peel (1987, 1991) were derived from sample JSP 1982−01. Parkhaev (2002) cited Yochelcionella americana as type species of a new genus, Runnegarella Parkhaev, 2002 , but this is treated as a junior synonym of Yochelcionella .

Stratigraphic and geographic range.— Late Early Cambrian of Pennsylvania and western Newfoundland .