no UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFERA 



large chambers which are highly arched, distinctly elongated in the direction of 

 coiling and increase slowly in size ; on the ventral side the chambers are 5, large, 

 ovoid, and distinctly overlapping while they increase slowly in size ; each chamber is 

 surrounded by a horseshoe-shaped, delicately beaded raised ridge ; sutures on the 

 dorsal side strongly curved, distinctly raised, much thickened and limbate ; on the 

 ventral side the sutures are strongly curved forward, slightly raised and limbate; 

 umbilicus roughly pentagonal in outline, wide, deep, surrounded by much-thickened 

 ridges and covered by complex tegilla, of which remnants are still preserved ; 

 primary apertures interiomarginal, umbilical ; tegilla, with accessory apertures, only 

 poorly preserved ; wall calcareous, perforate except for the imperforate keels, 

 peripheral band and tegilla ; surface smooth. 



Dimensions of described specimen. 

 Maximum diameter = 0-41 mm. 

 Minimum diameter = 0-35 mm. 



Thickness = 0-22 mm. 



Remarks. Gandolfi (1955) considered this subspecies to be the ancestral stock 

 from which both the G. fornicata and the G. contusa groups have evolved, through 

 G. fornicata fornicata Plummer in the former, and G. contusa scutilla Gandolfi in the 

 latter. He also mentioned a somewhat dubious relationship with what he described 

 as the G. caliciformis-intermedia group and suggested the evolution of the present 

 subspecies from G. lapparenti lapparenti (Brotzen) [= G. linneiana linneiana 

 (d'Orbigny)]. 



The present study substantiates Gandolfi's suggestion in part, namely that 

 G. fornicata manaurensis evolved from G. linneiana linneiana (d'Orbigny) and that 

 it possibly evolved into G. fornicata fornicata Plummer. Transitional stages 

 between the present subspecies and G. tricarinata tricarinata (Quereau), were also 

 recorded (e.g. PI. 14, figs. ya-c). 



Specimens of G. fornicata manaurensis , although rare in the samples studied, 

 compare well with Gandolfi's original description and figures, and with topotype 

 material kindly forwarded to the present author by Dr. R. Gandolfi. 



Hypotypes. P45535-36. 



Horizon and locality. Figured specimen from Sample No. 14, G. A 314 

 section. 



Stratigraphical range. Globotruncana fornicata manaurensis was described by 

 Gandolfi (1955) from the Manaure shale of northeastern Colombia where he considered 

 its range as Coniacian-Santonian. In the Esna-Idfu region it occurs as a very rare 

 form in the Lower Maestrichtian G. fornicata Zone only. 



Globotruncana fundiconulosa Subbotina 



J 953 Globotruncana fundiconulosa Subbotina : 200, 201, pi. 14, figs, la-^c ; pi. 15, figs. 



\a~ib. 

 IQ 55 Globotruncana wiedenmayeri wiedenmayeri Gandolfi : 71, pi. 7, figs. ^a-c. 

 ? 1955 Globotruncana wiedenmayeri magdalenaensis Gandolfi : 72, pi. 7, figs. j,a-c. 



