IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 127 



Globotruncana orientalis sp. nov. has possibly evolved from G. area (Cushman) by 

 the flattening of the ventral side and the reduction of the ventral keels on the last 

 chambers. This is substantiated by the fact that such tendencies were clearly 

 observed in specimens of G. area (Cushman). On the other hand, G. orientalis has 

 probably evolved into G. esnehensis Nakkady & Osman, although no direct evidence 

 was recorded. 



Holotype. P. 45549. 



Paratypes. P. 45550. 



Horizon and locality. Holo- and paratypes from sample No. 18, W. El-Sharaw- 

 na section. 



Stratigraphical range. Globotruncana orientalis sp.nov. appears as a common 

 to abundant form in the Lower Maestrichtian G. fornicata Zone of the sections 

 studied. It continues as an abundant form in the overlying G. gansseri Zone, 

 fading out gradually towards its top, and dies out completely in the basal part of the 

 G. esnehensis Zone. 



Globotruncana rosetta pettersi Gandolfi 



I 955 Globotruncana rosetta pettersi Gandolfi : 68, pi. 6, figs, ^a-^c, text-fig. 11a. 



1961 Globotruncana cf. rosetta pettersi Gandolfi ; Corminboeuf : 113-114, pi. 1, figs. $a-c. 



Remarks. Globotruncana rosetta pettersi was first described by Gandolfi (1955) as 

 a new subspecies from the lower Colon shale of northeastern Colombia where he 

 considered its range as Campanian. He stated that the form is entirely single 

 keeled, but examination of topotype specimens kindly sent by him to the present 

 author, showed forms with 2 keels on the early part of the last whorl, becoming 

 single keeled on the later chambers, and others with an entirely single keeled last 

 whorl. The entirely single keeled form is similar to the G. gansseri group, especially 

 to G. gansseri gandolfii subsp. nov. from which it is only distinguished by its smooth 

 surface. Gandolfi also stated that G. rosetta pettersi was found to disappear when the 

 first G. gansseri gansseri starts, but in the present study G. rosetta pettersi occurs as a 

 common form in the lower part of the G. gansseri Zone. It was neither recorded in 

 the underlying G. fornicata Zone nor in the upper part of the G. gansseri Zone. This 

 clearly indicates that the range of this subspecies is only Middle Maestrichtian, while 

 Gandolfi considered it as Campanian. However, as previously mentioned, the 

 Colon shale, which Gandolfi considers as Campanian-Maestrichtian, most probably 

 belongs to the Maestrichtian alone, as suggested by its planktonic foraminiferal 

 content. This is substantiated by the fact that the present subspecies was also 

 recorded from the Maestrichtian of Switzerland as G. cf. rosetta pettersi Gandolfi by 

 Corminboeuf (1961). 



Hypotype. P. 45551. 



Horizon and locality. Hypotype from sample No. 23 W. El-Sharawna section. 



