STUDIES m FORAMESriFERA 



45 



fore the first valid name for the species originally de- 

 scribed as PuLvinvlina area. 



The true apertural characters of this genus were not 

 given in the original description (Cushman, 1927, p. 91) 

 which stated only "aperture on the ventral side." In 

 his textbook (1928, p. 311) Cushman separated Qloho- 

 rotalia and Globotruncana solely on the basis of the 

 periphery, the former "periphery acute or rounded, 

 with a single keel," the latter "periphery truncate, 

 usually with a double keel." In the generic description 

 of Globotruncana he added, "aperture on the ventral 

 side, often in well-preserved specimens with a thin 

 plate-like structm-e over the umbilical area." 



GaUoway (1933, p. 332) described Globotruncana as 

 having the "aperture a slit at the base of the last cham- 

 ber opening into the large lunbilicus," and placed it in 

 the Orbulinidae, while placing Globorotalia (p. 278) in 

 the Rotaliidae, subfamily Rotahinae. Galloway's key 

 separated Globotruncana from Globigerina d'Orbigny 

 only by its having hmbate sutures. 



Glaessner (1948, p. 150) included Globotruncana and 

 Globorotalia in the Globorotaliidae, and stated of 

 Globotruncana, "aperture large, basal, leading from each 

 chamber into the wide umbilicus which is often con- 

 cealed by a thin perforate plate." 



Some of the French workers, evidently on the basis 

 of Cushman and Galloway's earlier descriptions, con- 

 sidered Globotruncana to have a single aperture, as 

 that of Globorotalia, separating the two only on the 

 peripheral characters. Marie (1941, p. 237) commented 

 on the separation of Globorotalia and Globotruncana 

 according to the munber of keels, and considered this 

 basis for subdivision invalid. His key considered 

 Globorotalia as having a single terminal apertm-e, on the 

 last chamber face. He then described the new genus 

 Rosalinella, with apertures, particularly in the chambers 

 of the last whorl, opening into the umbihcus. He 

 placed Globotruncana Cushman, 1927, in the synonymy 

 of his new genus, with Rosalina of de Lapparent (not 

 d'Orbigny), etc., selecting as type species Rosalina 

 linneiana d'Orbigny. As Globotruncana is a valid name 

 and antedates Rosalinella, the latter becomes a junior 

 synonym. The type species, Rosalina linneiana d'Or- 

 bigny, was described from Recent sands of Cuba, 

 where it is undoubtedly reworked from the outcropping 

 Cuban Cretaceous strata. 



Reichel (1949, p. 600) considered Globotruncana to 

 have four subgenera: Globotruncana, s. s., Rotalipora 

 Brotzen, Thalmanninella Sigal and Ticinella Reichel. 

 The latter three subgenera of Reichel are here con- 

 sidered unrelated to Globotruncana, and are fully dis- 

 cussed under Rotalipora. 



Sigal (1952, p. 236) stated that Globotruncana and 

 Globorotalia had been differentiated by the number of 

 keels, but that in reality the position of the apertiu-e 

 was a more certain criterion, and he thus recognized as 

 genera (not subgenera) Ticinella Reichel (with barely 

 delineated keel), Thalmanninella Sigal (with one keel), 

 both with secondary umbilical apertures; Rotalipora 

 Brotzen with one keel and secondary apertures in 



sutural slits, and Globotruncana, s. s., with one or two 

 keels without secondary apertures. 



However, in Globotruncana, s. s., only the accessory 

 apertures of the tegilla are visible in perfect specimens, 

 the primary apertiu-es being visible only when the 

 tegilla are broken out in preservation or in the prepa- 

 ration of the fossil material for study. These tegilla 

 and accessory apertures are present on fully preserved 

 specimens of every species. 



Rugotruncana was separated from Globotruncana by 

 Bronnimann and Brown (1956) because of a surface 

 ornamentation of discontinuous ridges. The genera 

 are otherwise identical, and Bronnimann and Brown 

 admitted (p. 546) that "the morphologic differences 

 between the two genera are shght." We do not regard 

 surface ornamentation as a character of generic value, 

 hence Rugotruncana is here considered a synonym of 

 Globotruncana. In addition to the type species, Bron- 

 nimann and Brown listed other ornamented Globo- 

 truncana which they considered to belong to Rugo- 

 truncana, among which were G. intermedia BoUi and 

 G. mayaroensis Bolli. These two species differ from 

 Globotruncana in lacking an open lunbilicus, in having 

 only a single tegillum which extends from the final 

 chamber, and has only infralaminal accessory apertures, 

 and the primary aperture is extraumbilical-iunbilical 

 in position, instead of truly umbilical. These two 

 species we place in the new genus Abathomphalus, and 

 G. mayaroensis is the type species. 



Bucherina was described by Bronnimann and Brown 

 as a monotypic genus from the Maestrichtian of Cuba, 

 which resembles Globotruncana and Rugotruncana in 

 having a keel and small apertural flaps, but was said to 

 differ in that these flaps do not extend across the 

 mnbilicus to form a true cover plate (tegilla). In 

 nearly all species of Globotruncana these fragile tegilla 

 are only partially preserved, and only very rare speci- 

 mens show them as well preserved as in the specimens 

 here figured. Tegilla were not recognized even in the 

 type species of Globotruncana until many years after its 

 original description, and they have not been mentioned 

 in the origiaal descriptions of the majority of species. 

 It is probable that better preserved specimens of 

 Bucherina sandidgei will also show the complete imi- 

 bilical tegilla, and we regard Bucherina as a synonym 

 of Globotruncana. 



Hofker (1956, p. 319) proposed the generic name 

 Marginotruncana, with Rosalina marginata Reuss as 

 type species. He considered Globotruncana to have 

 a strongly reduced protoforamen (primary aperture), 

 which is no longer an open slit, and Marginotruncana 

 was said to have lost the protoforamen or to have it 

 fused with a deuteroforamen (secondary aperture). 

 The diagrammatic figures in his text-fig. 1 are highly 

 misleading, as there are not two openings in the final 

 chamber of true Globotruncana, and there is no extra- 

 umbilical opening into the chamber. If such openings 

 exist in specimens studied by Hofker, they are totally 

 unUke those of the type species of the genus, and his 

 specimens undoubtedly are of a form referable to the 



