PEROUVIANELLA G. Bizon, J. J. Bizon,Fourcade, and Vachard, 1975

 

 

Type species: Orbiculina peruviana G. Steinmann, 1930 (*3066), p. 152.

Archaias (Perouvianella) G. Bizon, J. J. Bizon, Fourcade, and Vachard. 1975 (*245), p. 1157.

Test lenticular to discoidal, megalospheric test up to 1.5 mm in diameter, thin-walled proloculus and flexostyle followed by plani­spiral and involute whorls, rapidly increasing from about twelve chambers in the earliest whorl to twenty or thirty in the next few whorls, rarely may tend to uncoil in the adult, microspheric test larger, may be over 12 mm in diameter, planispiral throughout and chambers never completely annular, interior with radial pillars of triangular section arising from the chamber floor between the apertural foramina to extend about halfway into the chamber, producing small rectangular chamberlets in the lower part of the marginal zone of the chambers, radial pillars of successive chambers aligned, central part of the cham­bers subdivided by one to three rows of similarly aligned interseptal pillars, sutures weakly depressed; wall calcareous, porcelaneous, rel­atively thick, surface smooth; intercameral foramina and probably external aperture of rows of small circular pores. U. Cretaceous (Santonian); Peru.

 

Remarks: No holotype was selected by Steinmann. but Bizon et at. (1975. *245) designated as "holotvpe" ( recte lectotype) Stein­mann's specimen (1930. *3066, fig. 185 B-D; Geologisch-Palaontologisches Institut, University of Bonn).