SABELLOVOLUTA Loeblich and Tappan, 1985
Type species: Spirolina humboldti Reuss, 1851 (*2574), p. 65; OD.
Sabellovoluta Loeblich and Tappan, 1985 ( *1923), p. 101.
Test free, large, early stage close coiled, with a single whorl of four to five semiarcuate chambers as seen in longitudinal section, later uncoiling and rectilinear, with two to three inflated and strongly overlapping uniserial chambers, that range from wedge shaped in transverse section and broadest toward the inside of the coil to a nearly symmetrical terminal chamber of circular section, periphery rounded; wall coarsely agglutinated with larger grains in a finer groundmass, very thick and alveolar in structure, large alveoles opening into the chamber cavity but narrowing to canaliculi and may branch toward the exterior, total wall thickness approaching that of the chamber cavity, surface grainy but even; aperture in the enrolled stage a short vertical areal slit that may be slightly off center, in the uncoiled stage becoming terminal, straight to slightly curved, and produced on a short neck. L. to M. Oligocene; Germany; Austria.
Remarks: Sabelloyoluta differs from Ammobaculites in the broad, low, and curved early chambers, more produced and more strongly overlapping uniserial chambers, thick alveolar wall, and slit aperture produced on a neck and differs from Popoyia in the involute coil, fewer chambers per whorl, greater chamber overlap, arched rather than straight sutures, very thick and complex alveolar wall, areal aperture, and produced apertural neck.