76 



UNITED STATES NATIONAL MUSEUM BtTLLETIN 215 



Cushman and Renz in possessing a more distinct but 

 thinner peripheral keel and more chambers in the last 

 whorl. G. formosa gracilis is regarded as the ancestor 

 of G. formosa formosa Bolli, new species, new sub- 

 species. 



Globorotalia formosa formosa Bolli, new species, new subspecies 



Plate 18, Figubes 1-3 



Globorotalia velascoensis (Cushman), Cushman and Renz (not 

 Cushman, 1925), Cushman Lab. Foram. Res., Spec. Publ. 

 18, p. 47, pi. 8, figs. 13, 14, 1946. 



Shape of test very low trochospiral, spiral side almost 

 flat, inner whorls occasionally slightly raised, umbilical 

 side strongly convex; equatorial periphery slightly 

 lobate, nearly circular; axial periphery angular with 

 pronounced keel which is ornamented with spines in 

 well preserved specimens. Wall calcareous, perforate, 

 surface finely to distinctly spiaose, especially on the 

 umbilical side. Chambers angular, inflated; 15-18, 

 arranged in about 3 whorls; the 6-8 chambers of the 

 last whorl increasing slowly in size. Sutures on spiral 

 side, curved; on umbHical side radial, depressed. 

 Umbilicus fairly wide, deep, open. Aperture a low 

 arch;interiomarginal, extraumbUical — umbilical. Coil- 

 ing about 90 percent dextral in the Globorotalia formosa 

 formosa zone, becoming predominantly sinistral in the 

 Globorotalia aragonensis zone (up to 64 percent). 

 Largest diameter of holotype 0.65 mm. 



Stratigraphic range : Globorotalia formosa formosa 

 zone and Globorotalia aragonensis zone. Lizard Springs 

 formation. 



Locality: Holotype (USNM P5056) from Ravine 

 Ampelu, Lizard Springs area, about iK 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 formosa formosa Bolli, new 

 species, new subspecies, differs from the related G. 

 formosa gracilis Bolli, new species, new subspecies, in 

 its more robust test, larger size, and greater number of 

 chambers in the last whorl. G. formosa formosa differs 

 from G. aragonensis Nuttall in its slightly larger size, 

 more lobate periphery, greater number of chambers in 

 the last whorl, and wider umbihcus. Also, it has a 

 much more restricted stratigraphic range. 



Globorotalia velascoensis (Cusbman) 

 Plate 20, Figures 1-4 



Puhinulina velascoensis Cushman, Contr. Cushman Lab. Foram. 



Res., vol. 1, pt. 1, p. 19, pi. 3, figs. 5a-c, 1925. 

 Globorotalia wilcoxensis Cushman and Ponton var. acuta Toul- 



MiN, Journ. Paleontol., vol. 15, No. 6, p. 608, pi. 82, figs. 6-8, 



1941. For additional references see Cushman and Ber- 



mudez (1949, pp. 39, 41). 



Shape of test very low trochospiral, spiral side flat; 

 umbilical side strongly convex; in large specimens the 



outer wall of the chambers of the last whorl may be 

 somewhat concave; equatorial periphery nearly circular; 

 axial periphery angular with distinct keel which may be 

 spinose. Wall calcareous, perforate, surface smooth, 

 around umbilical area often rugose. Chambers angu- 

 lar, inflated; 12-18, arranged in 2}^3 whorls, the five 

 chambers of the last whorl increasing moderately in 

 size. Sutures on spiral side cm-ved, may be slightly 

 raised; on umbilical side radial, depressed. Umbilicus 

 narrow and deep in small specimens, becoming wider 

 in large specimens. Aperture a low arch; interiomar- 

 ginal, extraumbilical — ^umbUical. Coiling random in 

 the upper part of the Globorotalia pusilla pusilla zone, 

 becoming sinistral in the Globorotalia pseudomenardii 

 and Globorotalia velascoensis zones (about 95 percent). 

 Largest diameter of figured hypotypes 0.49 mm. (pi. 

 20, figs. 1-3), and 0.27 mm. (pi. 20, fig. 4). 



Stratigraphic range: Globorotalia pusilla pusilla 

 zone to Globorotalia velascoensis zone, Lizard Springs 

 formation. 



Locality: Figured hypotypes (USNM P5057 and 

 P5058) from Trinidad Leaseholds, Ltd., Guayaguayare 

 well 159, Trinidad (coordinates N:151361 links; 

 E:554095 links), sample from core 4,324-30 feet (TLL 

 233004). 



Remarks: Globorotalia velascoensis (Cushman) shows 

 considerable variety in size and shape (especially of the 

 umbilical area) . Material studied from a Velasco shale 

 sample of Mexico shows every intermediate stage be- 

 tween very small forms with a narrow umbilicus {G. 

 wilcoxensis var. acuta Toulmin group) and large speci- 

 mens with a wide umbilicus ((?. velascoensis, s. s., 

 group). The same has been observed throughout the 

 life range of the species in Trinidad sections. Forms 

 belonging to both these groups are therefore regarded 

 as G. velascoensis, of which G. wilcoxensis var. acuta is a 

 synonym. This confii'ms Grimsdale (1951) who re- 

 gards G. wilcoiensis var. acuta as a variety of G. 

 velascoensis. 



Globorotalia velascoensis appears in the upper part of 

 the G. pusilla pusilla zone where it may have branched 

 off from the G. angulata (White) group though no clearly 

 intermediate forms have been observed. At the end 

 of the G. velascoensis zone, the species becomes extinct 

 in Trinidad together with numerous other planktonic 

 and benthonic forms. The author's previous assump- 

 tion (Bolli, 1952) that G. velascoensis occurs in the 

 upper Lizard Springs and may be regarded as the ances- 

 tor of G. aragonensis Nuttall is no longer maintained. 

 G. velascoensis is in fact restricted to the lower Lizard 

 Springs; the forms previously described imder this 

 name from the upper Lizard Springs are now regarded 

 as a new species {G. formosa gracilis BoUi, new species, 

 new subspecies, and G. formosa formosa BoUi, new 

 species, new subspecies) probably developing from the 

 G. aequa Cushman and Renz group. This is supported 

 by the coiling ratios of the species under discussion. 

 G. velascoensis coils almost exclusively sinistraUy before 

 its extinction at the end of the Globorotalia velascoensis 



