A New Spheromorphic Problematic of the Genus Gaparella from the Lower Cambrian of Western Mongolia

Abstract

A new problematic spheromorphic microfossil Gaparella elenae sp. nov. is described from the lower Tommotian (Lower Cambrian) in the Hevte-Tsakhir-Nuruu Ridge, Western Mongolia, and a new combination Gaparella kuanchuanpuensis (Qian, 1977) is proposed. Despite its very peculiar morphology, the genus Gaparella Missarzhevsky in Missarzhevsky and Mambetov, 1981 is usually considered as a junior synonym of the genus Archaeooides Qian, 1977. The taphonomic variability of Mongolian specimens of Gaparella is demonstrated, and their morphology is reconstructed: these were hollow spheres, with a thin perforated double-layered wall; with a system of cavities between the pores, which were scattered on small elevations, with a system of canals in between; the wall may have been organic with an admixture of mineral components. These fossils were probably planktonic filter feeders. Their level of organization appears to be consistent with Porifera; most likely these were juvenile forms.