212 ll'PER CRETACEOUS-LOWER TERTIARY FORAMINIFERA 



and from the holotype G. pseudotopilensis, while that of Said (i960) probably belongs 

 to G. esnaensis. 



Berggren (1960a) and Bermudez (1961) described as Globororalia esnaensis (Le 

 Roy) and Globigerina esnaensis Le Roy, respectively forms which are different from 

 the holotype of Le Roy. However, the former author (pi. 13, figs 3^-40) described 

 as Globorotalia wilcoxensis Cushman & Ponton, forms which probably belong to 

 G. esnaensis. Berggren (1960& : 50-51) wrongly considered G. esnaensis figured by 

 Nakkady (1959) as G. soldadoensis Bronnimann, while Hillebrandt (1962 : 142-143) 

 included G. esnaensis in the synonymy of a form described as Globorotalia (Acarinina) 

 soldadoensis (Bronnimann). 



Globorotalia esnaensis (Le Roy) is distinguished by its large test ; small number of 

 chambers ; slightly flattened dorsal side and strongly protruding ventral one ; its 

 quadrate, lobate, equatorial periphery and rounded axial periphery ; its radial, 

 depressed sutures on both sides and rough nodose surface. 



The species probably evolved from G. tribulosa Loeblich & Tappan by the increase 

 in the size of test and in the surface rugosity, and by the development of a more 

 tightly coiled test, less lobate periphery, and a much narrower aperture. On the 

 other hand, G. esnaensis is believed to have evolved into G. wilcoxensis Cushman & 

 Ponton through G. whitei Weiss, by further flattening of the dorsal side, the develop- 

 ment of a sub-acute axial periphery in the later part of the test, and by the reduction 

 in the surface rugosity on the last chambers. Similarly, it has also probably involved 

 into G. berggreni sp. nov. as mentioned above (p. 201). 



Hypotype. P.45607. 



Horizon and locality. Figured specimen from sample No. 49, Gebel Owaina 

 section. 



Stratigraphical range. The species was first described from the basal part of 

 the Esna shale (Unit II of Le Roy) of the Maqfi section, Farafra Oasis, Egypt ; it was 

 found to be abundant throughout this unit, becoming scarce higher in the section. 

 Le Roy tentatively considered this unit to be Lower Eocene in age while Said & 

 Kerdani (1961) considered it to be Landenian. 



Nakkady (1959) recorded Globigerina esnaensis Le Roy throughout the Maestrich- 

 tian-Paleocene of the Um-El-Ghanayem section, Kharga Oasis, Egypt. Evidently 

 he confused this important species with superficially similar Rugoglobigerina and 

 Globorotalia species, thus completely obscuring its true range. 



G. esnaensis was also recorded from the Lower Tertiary of the northern Caucasus 

 (Subbotina 1953), the Paleocene of northern Sinai, Egypt (Said & Kenawy 1956), 

 the Upper Landenian-Lower Eocene of the Gulf and Atlantic Coastal Plains (Loe- 

 blich & Tappan 1957a, b), the Lower Eocene of Denmark (Berggren 1960a), the 

 ? Landenian Esna shales of Luxor section, Egypt (Said i960), the Landenian Esna 

 shales of the Farafra Oasis, Egypt (Said & Kerdany 1961), and from the type 

 Ilerdian of Spain and the Ilerdian of Mont Cayla, France (Gartner & Hay 1962). 



In the Esna-Idfu region G. esnaensis (Le Roy) appears in the middle of the G. 

 velascoensis Zone. It floods the upper part of this zone characterizing, together with 



