SCHACKOINA Thalmann, 1932

 

 

Type species: Siderolina cenomana Schacko, 1897 (*2740), p. 166; OD.

Hantkenina Schackoina) Thalmann, 1932 ( *3151). p. 288. Schackoina Cushman, 1933 (*766), p. 267 ( nom. transl.).Test small, with early low trochospiral stage, later nearly planispiral, early chambers globular, later ones radially elongate and laterally compressed. one or more elongate tubulospines extending from the midline of each chamber on the periphery. biumbilicate. sutures de-pressed; wall calcareous, very finely perfo­rate, optically radial. surface slightly hispid; aperture a low interiomarginal and equato­rial arch bordered by a distinct lip, part of the lateral extensions of the aperture into the umbilicus may remain as relict apertures. L. Cretaceous (Albian) to U. Cretaceous (Maastrichtian): cosmopolitan.