STTTDIES IN FORAMINirERA 



75 



Locality: Figured hypotypes (USNM P5051 and 

 P5052) from Trinidad Leaseholds, Ltd., well Guay- 

 aguayare 159, Trinidad (coordinates N:151361 links; 

 E: 554095 links), sample from core 3,813-25 feet (TLL 

 232995). 



Remarks: No close morphologic or stratigraphic con- 

 nection is evident between Globoroialia aequa Cushman 

 and Renz and the coarsely spinose G. crassata (Cush- 

 man) from the middle to upper Eocene. Specific rank 

 is therefore given to G. aequa. It is distinguished from 

 the related G. angulata (White) by having a more 

 spinose surface, a relatively large iiltimate chamber 

 and in a distinct preference for dextral coiling. A com- 

 parison of the holotypes of G. aequa and G. lacerti 

 Cushman and Renz clearly indicates that the latter is 

 a junior synonym. G. aequa is regarded as the ancestor 

 of G. rex Martin and G. formosa gracilis Bolli, new 

 species, new subspecies. 



Cloborotalia rex Martin 

 Plate 18, Figures 10-12 



Globorotalia rex Martin, Stanford Univ. Publ., Univ. Ser., Geol. 

 Sci., vol. 3, No. 3, p. 117, pi. 8, fig. 2, 1943. 



Globorotalia simulatilis (Schwager), Le Roy (not Schwager, 

 1893), Geol. Soc. Amer., Mem. 54, pp. 32-33, pi. 9, figs. 

 1-3, 1953. 



Shape of test, very low trochospiral, spiral side flat or 

 slightly convex, umbilical side strongly convex; equa- 

 torial periphery lobate; axial periphery angular with 

 distinct peripheral keel, often ornamented with spines. 

 Wall calcareous, perforate, surface coarsely spinose. 

 Chambers angular, inflated; about 12, arranged in 2-2}^ 

 whorls, the 4-5 chambers of the last whorl increasing 

 rapidly in size. Sutm-es on dorsal side strongly curved; 

 on umbilical side radial, depressed. Umbihcus narrow, 

 deep, open. Aperture a low arch; interiomarginal, 

 extraumbilical-umbilical. Coiling between 90 and 100 

 percent dextral. Largest diameter of figured hypotype 

 0.56 mm. 



Stratigraphic range: Globorotalia rex zone to 

 Globorotalia formosa formosa zone, Lizard Springs 

 formation. 



Locality: Figured hypotype (USNM P5053) from 

 Trinidad Leaseholds, Ltd., well Guayaguayare 159, 

 Trinidad (coordinates N:151361 links; E:554095 links), 

 sample from core 3,707-13 feet (TLL 232994). 



Remarks: Globorotalia rex Martin differs from the 

 related G. aequa Cushman and Renz in being more 

 robust and in having a distinct thick peripheral keel. 

 G. rex is regarded as the ancestor of G. aragonensis 

 Nuttall. 



Globorotalia aragonensis Nuttall 



Plate 18, Figures 7-9 



Globorotalia aragonensis Nuttall, Journ. Paleontol., vol. 4, 

 No. 3, p. 288, pi. 24, figs. 6-8, 10, 11, 1930.— Cushman and 

 Renz, Cushman Lab. Foram. Res., Spec. Publ. 24, p. 40, 

 pi. 8, figs. 1, 2, 1948. — Cushman and BERMUDEZi Contr. 

 Cushman Lab. Foram. Res., vol. 25, pt. 2, pp. 38, 39, 

 pi. 7, figs. 13-15, 1949. 



Shape of test very low trochospiral; spiral side almost 



flat or slightly convex, umbilical side strongly convex 

 and slightly inflated; equatorial periphery nearly cir- 

 cular; axial periphery angular with keel, which is 

 ornamented with small spines in well preserved speci- 

 mens. Wall calcareous, perforate; surface, especially 

 the umbilical side, rugose or with short, thick spines. 

 Chambers angular, inflated; 15-18, arranged in about 3 

 whorls; the 6-7 chambers of the last whorl increasing 

 slowly in size. Sutures on spiral side curved, often 

 slightly raised and beaded; on umbilical side radial, 

 slightly depressed. Umbilicus narrow, deep, open. 

 Aperture a low arch; interiomarginal, extraumbilical- 

 umbilical. Coiling preponderantly dextral in the lower 

 part of the Globorotalia formosa formosa zone (over 90 

 percent) ; in its upper part reversing to a strongly pre- 

 dominant sinistral coiling in the Globorotalia aragonensis 

 zone (about 90 percent). Largest diameter of figured 

 hypotype 0.55 mm. 



Stratigraphic range; Globorotalia formosa formosa 

 zone to Globorotalia aragonensis zone; continuing into 

 the Navet formation. 



Locality: Figured hypotype (USNM P5054) from 

 Ravine Ampelu, Lizard Springs area, about 1% mile 

 southeast of the road junction of the Rio Claro — 

 Guayaguayare Road {8% M.P.) and the old Trinidad 

 Central Oilfields Road leading to the abandoned Lizard 

 Springs oilfield, southeast Trinidad (coordinates 

 N: 186505 links; E:556755 links), sample KWB 6972 

 (TLL 102301). 



Remarks: Globorotalia aragonensis Nuttall differs 

 from the ancestral G. rex Martin in having a more 

 compact test, less lobate periphery, stronger peripheral 

 keel, a greater number of chambers, and a strong 

 preference for sinistral coiling in the younger specimens. 



Globorotalia formosa gracilis Bolli, new species, new subspecies 

 Plate 18, Figures 4-6 



Shape of test very low trochospiral, spiral side almost 

 flat or slightly convex, umbilical side distinctly convex; 

 equatorial periphery lobate: axial periphery angular 

 with a faint keel ornamented with spines. Wall cal- 

 careous, perforate, surface distinctly spinose. Cham- 

 bers angular, inflated; about 12, arranged in 2 }^-3 whorls, 

 the 5-6 chambers of the last whorl increasing rapidly 

 in size. Sutures on dorsal side slightly curved to 

 oblique, slightly depressed; on umbilical side radial, 

 distinctly depressed. Umbilicus fairly narrow, deep, 

 open. Aperture a low arch; interiomarginal, extra- 

 umbilical-umbihcal. Coiling between 90 and 100 per- 

 cent dextral. Largest diameter of holotyp« 0.50 mm. 



Stratigraphic range: Globorotalia rex zone to 

 Globorotalia formosa formosa zone, Lizaid Springs 

 formation. 



Locality: Holotype (USNM P5055) from Trinidad 

 Leaseholds, Ltd., well Guayaguayare 159, Trinidad 

 (coordinates N:151361 links; E:554095 finks), sample 

 from core 3,707-13 feet (TLL 232994). 



Remarks: Globorotalia formosa gracilis BoUi, new 

 species, new subspecies, differs from the related G. aeqva 



