IN THE ESNA-IDFU REGION, NILE VALLEY, EGYPT 89 



Glaessner (1937a) and Keller (1946) described as G cf. conica White and G. conica 

 White respectively, forms which possibly belong to G. contusa Cushman. The 

 form described by Cushman & Renz (1947) as G- conica is doubtful, while that 

 described by Cita (1948) can probably be assigned to G. orientalis sp. nov. Again, the 

 form described by Bolli (1951) as G. conica White is probably G. stuarti stuarti 

 (de Lapparent). 



Tilev (1951, 1952) described as G. conica White, a form with only 5f chambers in 

 the last whorl, and distinctly outlined chambers on the ventral side. This form is 

 questionably related to the present species. However, the fact that Tilev included 

 in the synonymy of his G. conica, forms such as G. conica var. plicata White and G. 

 linnei caliciformis (de Lapparent), which are probably synonymous with G. contusa 

 contusa (Cushman) and G. contusa patelliformis Gandolfi respectively, throws doubt 

 on the identification of his specimens. Tilev also described as G. conica-caliciformis 

 nom. nov., a form which he considered as transitional between G. conica White and 

 G. caliciformis (de Lapparent). However, as mentioned above, G. caliciformis is a 

 probable synonym of G. contusa (Cushman), a species which is morphologically 

 distinct from G. conica. This intermediate form described by Tilev may belong to 

 G. orientalis sp. nov. 



Subbotina (1953) described as G. conica White, forms which are G. contusa scutilla 

 Gandolfi and G. contusa patelliformis Gandolfi. 



Gandolfi (1955) considered G. conica White as a subspecies of G. stuarti (de Lap- 

 parent), and thus changed its name to G. stuarti conica (White). However, as 

 mentioned under G. stuarti stuarti, the morphological characters and stratigraphical 

 ranges of the two species warrant their separation. Moreover, the form described by 

 Gandolfi (1955) is different from both the holotype of White and the known forms of 

 G. stuarti, and should be renamed and redescribed in more detail. Following 

 Gandolfi (1955), Said & Kenawy (1956) incorrectly emphasized the relationship 

 between G. conica White and G. stuarti (de Lapparent). 



Pessagno (i960, 1962) described as G. conica White, forms which were said to 

 have a double keel on the early chambers of the last whorl, giving way to a single 

 keel on the following chambers. Such forms probably belong to G. orientalis sp. nov. 



Globotruncana conica White is unique among the known spiroconvex Globotruncana 

 species. No morphologically similar forms have yet been recorded from older strata, 

 and thus very little is known about the evolutionary history of the species. However, 

 it is possible that G. conica evolved from either G. sharawnaensis sp. nov. or 

 G. orientalis sp. nov. The confused stratigraphical range of the species makes it 

 difficult to decide, for the time being, although forms of G. sharawnaensis with an 

 entirely single keel appear closely similar to G. conica. 



Hypotype. P.45520. 



Horizon and locality. Figured specimen from sample No. 16, Gebel Owaian 

 section. 



