140 upper cretaceous-lower tertiary for aminifera 



Dimensions of described specimen. 

 Maximum diameter = 0-62 mm. 

 Minimum diameter = 0-52 mm. 



Thickness = 0-31 mm. 



Main variation. 



1. Chambers, 18-24, arranged in 3-4 whorls, generally dextrally coiled (all the 



specimens studied coiled dextrally). 



2. The last whorl is composed of 5-7 large chambers which tend to be roughly 



trapezoidal in the last part. 



Remarks. Pessagno (i960) described G. subspinosa as a new species, but in 

 1962, he regarded it as a subspecies of G. stuarti (de Lapparent). Lehmann (1963) 

 described as G. undulata n.sp. from the Santonian of the Tarfaya province, western 

 Morocco, a form which only differs from G. stuarti subspinosa in being raised on the 

 dorsal side. This form is doubtfully included in the synonymy of G. stuarti sub- 

 spinosa as it was recorded from slightly older strata. 



Globotruncana stuarti subspinosa is distinguished from G. stuarti stuartiformis by the 

 trapezoidal shape of its chambers on the dorsal side, and from G. stuarti stuarti by its 

 irregular, slightly lobate periphery, the strongly angular shape of its chambers on the 

 dorsal side which are much wider and less elongated in the direction of coiling, and 

 by the less regular rate of growth of its chambers. It is believed to have arisen from 

 G. stuarti stuartiformis in the early Campanian and to have evolved into G. stuarti 

 stuarti (de Lapparent) in the Upper Campanian or Lower Maestrichtian. The 

 stratigraphical ranges of these three forms favour this proposition. 



Hypotypes. P.45559. 



Horizon and locality. Figured specimens from sample No. 18, W. El- 

 Sharawna section. 



Stratigraphical range. G. stuarti subspinosa was first described from the 

 Parguera limestone and Rio Yauco mudstone formations of Puerto Rico and was 

 shown on Passagno's distribution chart (i960 : 89, chart 1) to be rare in his Lower 

 Campanian Praeglobotruncana gautierensis Subzone, common in his Upper Campanian 

 Rugoglobigerina rugosa-Globotruncana rosetta Subzone and in his lowermost 

 Maestrichtian Globotruncana lapparenti lapparenti Zonule. In 1962 (354-355, 

 charts 1, 2 and 4) he listed G. stuarti subspinosa as rare to common in the early 

 Campanian and rare to abundant in the early Maestrichtian. 



In the Esna-Idfu region, G. stuarti subspinosa is rare to common in the Lower 

 Maestrichtian G. fomicata Zone and continues up to the basal part of the Middle 

 Maestrichtian G. gansseri Zone, where it dies out completely. 



Globotruncana subcircumnodifer Gandolfi 



J 955 Globotruncana (Rugoglobigerina) circumnodifer subcircumnodifer Gandolfi : 44, pi. 2, 

 figs. 8a-c. 

 ? 1955 Globotruncana (Rugoglobigerina) pennyi subpennyi Gandolfi : 73, pi. 7, figs. ja-c. 



