146 UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFER A 



petaloid, flattened, or even slightly depressed chambers ; on the ventral side the 

 chambers are 6|, large, subcircular to ovoid, weakly inflated and slightly over- 

 lapping ; sutures on the dorsal side curved, raised, thickened and heavily beaded ; 

 on the ventral side they are slightly curved forward, depressed and beaded ; umbilicus 

 polygonal in outline, relatively wide, deep, surrounded by slightly raised, beaded 

 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 and 

 tegilla ; surface delicately papillose on the dorsal side, coarsely papillose on the 

 ventral. 



Dimensions of described specimen. 



Maximum diameter = 0-51 mm. 



Minimum diameter = 0-44 mm. 



Thickness = 0-25 mm. 



Remarks. Although the present form is clearly distinguished from the known 

 Globotruncana species, it was decided not to name it for the time being because of its 

 rarity. It is morphologically similar to G. area (Cushman), from which it is dis- 

 tinguished by its more compressed test, papillose surface, depressed ventral sutures 

 and single keel on the last chamber. It may have evolved from G. area (Cushman) 

 as suggested by their morphological features and stratigraphical distribution, 

 although no direct evidence was recorded. 



Material. P. 45566. 



Horizon and locality. Figured specimen from sample No. 20, W. El-Sharawna 

 section. 



Stratigraphical range. The present species is rare in the Middle Maestrichtian 

 G. gansseri Zone. 



Genus RUGOGLOBIGERINA Bronnimann 1952 



Type species. Globigerina rugosa Plummer 1926. 



1952 Rugoglobigerina Bronnimann : 16 (Type species : Globigerina rugosa Plummer 1926). 

 1956 Kuglerina Bronnimann & Brown : 557 (Type species : Rugoglobigerina rugosa rotundata 

 Bronnimann 1952). 



Rugoglobigerina glaessneri Gandolfi 

 1955 Globotruncana (Rugoglobigerina) glaessneri glaessneri Gandolfi ; 50, pi. 3, figs, zoa-c. 



Remarks. Rugoglobigerina glaessneri is common in both the Middle and Upper 

 Maestrichtian (G. gansseri and G. esnehensis Zones) of the sections studied. The 

 species was originally described from the Colon shale of northeastern Colombia which 

 was regarded by Gandolfi (1955) as of Campanian-Maestrichtian age, but is most 

 probably of Maestrichtian age only. The form described by Gandolfi as G. (R.) 

 glaessneri subglaessneri is probably a Globotruncana not a Rugoglobigerina. 



Hypotype. P.45649. 



