The Ostracod Fauna of the Eramosa Member of the Lockport Formation (Middle Silurian)

Abstract

Ostracods from the Eramosa member of the Lockport formation have been described from four quarries. These include three species of Paraechmina, one of Beyrichia (Velibeyrichia), Bolbiprimitia, Drepanellina, Kloedenella and Eukloedenella, and two species of Dizygopleura and Bythocypris. Two new genera, Dundasia end Parajonesites and four new species, Dundasia bicarinata, Parajonesites carinata, Bolbiprimitia punctosulcata, and Dizygopleura copensis have been proposed. One genus and species has not been identified. The vertical ranges of several species have been extended. The fauna appears to indicate shallowing conditions eastward from Dundas. Most species have been measured with respect to at least length and height, and from this the mean dimensions for each instar have been calculated. In most species the growth factors appear to vary systematically throughout ontogeny.