150 UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFER A 



Trinitella scotti Bronnimann 



1952 Trinitella scotti Bronnimann : 57, pi. 4, figs. 4-6 ; text-figs. 3oa-m. 



1956 Trinitella scotti Bronnimann ; Bronnimann & Brown : 555, pi. 23, figs. 13-15. 



1957 Rugoglobigerina scotti (Bronnimann) Bolli, Loeblich & Tappan : 43, pi. 11, figs. ^a-^c. 



Remarks. Trinitella scotti has been recorded from the Middle and Upper Maest- 

 richtian of the studied sections (the G. gansseri and the G. esnehensis Zones). It is 

 generally rare at the base of the Middle Maestrichtian, but gradually increases in 

 number upwards in the section becoming common to abundant. The species was 

 originally described from the Maestrichtian of Trinidad and was later recorded from 

 the Maestrichtian of Texas, Arkansas, Alabama, Puerto Rico and Cuba (Bronnimann 

 & Brown 1956) and from that of Trinidad and Texas (Bolli, Loeblich & Tappan 1957). 



Hypotype. P. 45656. 



Horizon and locality. Hypotype from sample No. 19, W. El-Sharawna 

 section. 



Family ROTALIPORIDAE Sigal 1958 



Subfamily HEDBERGELLINAE Loeblich & Tappen 1961 



Genus HEDBERGELLA Bronnimann & Brown 1958 



Type species. Anomalina lorneiana d'Orbigny var. trocoidea Gandolfi 1942. 



Remarks. The genus Hedbergella as defined by Bronnimann & Brown (1958) 

 and emended by Loeblich & Tappan (1961, 1964) only differs from Praeglobotruncana 

 Bermudez 1952, in lacking a keel or a poreless margin, and thus was included as a 

 subgenus of the latter by Banner & Blow (1959). However, the two forms are here 

 treated separately, although further study may prove the non-carinate forms to 

 have evolved imperceptibly into the carinate ones, as is the case in the genus Globo- 

 rotalia Cushman 1927 (see below). This may be substantiated by the fact that the 

 keel in Praeglobotruncana is generally weakly developed and that forms of Hedbergella 

 with pseudo-keel and/or a pinched out periphery have been recorded. Again, the 

 general tendency towards the development of more flattened chambers (characteristic 

 of Praeglobotruncana) from the globular ones (characteristic of Hedbergella) are also 

 documented. However, as only the youngest representatives of this genus are 

 recorded in the present study, no firm conclusion regarding their ancestry could be 

 reached. The classification proposed by Loeblich & Tappan (1961, 1964) has there- 

 fore been temporarily accepted. 



Hedbergella hessi compressifortnis (Pessagno) 

 1962 Praeglobotruncana hessi compressifortnis Pessagno : 360, pi. 5, figs. 1-7. 



Remarks. Hedbergella hessi compressifortnis is rare in the upper part of the 

 Lower Maestrichtian and in most of the Middle Maestrichtian of the sections studied. 

 The species was originally described from the Maestrichtian Rio Yauco formation 

 of Puerto Rico. 



