26 



UNITED STATES NATIONAL MUSEUM BULLETIN 215 



Genus Schackoina Thalmann, 1932 



Plate 2, Figubbs la-2 



Schackoina Thalmann, Eclog. Geol. Helvetiae, vol. 25, p. 289, 

 1932. 



Type species: Siderolina cenomana Schacko, 1896. 

 Fixed by original designation. 



Test free, early portion may be more or less trocho- 

 spiral, later becoming nearly planispiral; chambers 

 radially elongate with one or more elongate, tapering 

 hoUow tubulospines extending outward from the mid- 

 line of each chamber on the periphery; sutiu-es straight, 

 radial, depressed; wall calcareous, finely perforate, 

 surface smooth or very finely hispid; primary aperture 

 an interiomarginal arch, extraumbilical and tending to 

 become equatorial, may be bordered above by a 

 narrow Hp. 



Remarks: Schackoina differs from Hantkenina Cush- 

 man in being trochospiral and in having a simple 

 interiomarginal arched aperture, whereas Hantkeinina 

 has a triradiate aperture with a high sHt extending up 

 the face of the final chamber. 



It differs from Hastigerinoides Bronnimann in being 

 trochospiral and in having the tubulospines distinctly 

 separated from the main chamber cavity. 



Types and occttrhence: Figured hypotypes (USNM 

 P4644a, b) and unfigured hypotypes (USNM P4563) 

 of Schackoina cenomana (Schacko) from the Ceno- 

 manian Schloenbachia varians zone; unfigured hypo- 

 types (USNM P4562) from the Cenomanian Inoceramus 

 crippsi zone; all from Ziegelei Zeltberg, at Luneburg, 

 southeast of Hamburg, Province Niedersachsen, Ger- 

 many. Collected by H. T. and A. R. Loeblich, Jr. 



Range: Aptian to Maestrichtian. 



Genus Hantkenina Cushman, 1924 



Plate 2, Fiquhes 3a-8b 



Hantkenina Cushman, Proc. U. S. Nat. Mus., vol. 60, art. 30, 



p. 1, 1924. 

 Sporohantkenina Beemtjdez, Mem. Soc. Cubana Hist. Nat., 



vol. 11, p. 151, 1937. (Type species: Hantkenina brevispina 



Cushman, 1924. Fixed by original designation and mono- 



typy.) 

 Aragonella Thalmann, Amer. Journ. Sci., vol. 240, pp. 811, 813, 



818, 1942. (Type species: Hantkenina mexicana Cushman 

 var. aragonensis Nuttall, 1930. Fixed by original designa- 

 tion.) 



Applinella Thalmann, Amer. Journ. Sci., vol. 240, pp. 812, 813, 



819, 1942. (Type species: Hantkenina dumblei Weinzierl 

 and Applin, 1929. Fixed by original designation.) 



Hantkeninella Bronnimann, Joiirn. Paleontol., vol. 24, No. 4, 

 p. 399, 1950. (Type species: Hantkenina alabamensis 

 Cushman var. primitiva Cushman and Jarvis, 1929. Fixed 

 by original designation and monotypy.) 



Type species: Hantkenina alabamensis Cushman, 

 1924. Fixed by original designation. 



Test free, planispiral, involute, biconvex, biumbili- 

 cate; chambers rounded, ovate or radial elongate, 

 generally with a single relatively long and heavy spine 

 at the forward margin of each chamber on the periphery, 

 although they may rarely be lacking on one or more 



chambers, spines in the plane of coiling; sutm-es de- 

 pressed, radial; waU calcareous, finely perforate, radial 

 in structure, surface finely hispid, especially in the area 

 just beneath the aperture on the previous whorl; 

 primary aperture interiomarginal, equatorial, triradiate, 

 two of the "rays" forming a sht across the base of the 

 final chamber face, the third ray arising from the center 

 of this slit and extending up the face toward the peri- 

 pheral spine, flaring slightly to become rounded at its 

 upper end, the vertical slit bordered laterally by 

 apertural flanges which join above as a narrow lip. 



Remarks : In the original description of Hantkenina, 

 Cushman stated (1924, p. 1) that it included Siderolina 

 of Hantken (not Defrance), and "while they should 

 probably be referred to the Rotaliidae are very different 

 from Siderolites or Calcarina." In his classification 

 (1927, p. 64) Cushman placed it in a separate family, 

 the Hantkeninidae; he included with it Mimosina 

 Millett and Trimosina Cushman, and stated (p. 65), 

 "the family is related to the Heterohelicidae." 



In later publications (1933, p. 267) Mimosina and 

 Trimosina were placed by Cushman in the Buliminidae 

 and Schackoina Thalmann was placed with Hantkenina. 

 Galloway (1933, p. 266) placed Hantkenina in the 

 Nonionidae, stating (p. 264) that it "evolved from 

 Nonion by developing a long spine on each chamber." 



Bermudez defined Sporohantkenina in 1937, but the 

 type species selected is congeneric with true Hantkenina. 

 Thalmann (1942) defined three new subgenera of 

 Hantkenina: Cribrohantkenina, which included Ber- 

 mudez's forms (but not the Hantkenina brevispina of 

 Cushman), Aragonella, and Applinella. 



Cushman's test (1948) did not mention the latter two 

 subgenera, although he raised Cribrohantkenina to 

 generic status and stated (p. 328), "Further studies of 

 these forms seem to show that they were derived from 

 the Globigerinidae and were probably pelagic, at least 

 during part of their life history." 



Glaessner (1948, p. 149) placed the subfamily Hant- 

 kenininae in the family Globigerinidae, and Sigal (1952, 

 p. 235) recognized it as a separate family. Bermudez 

 (1952, p. 108) placed Hantkenina and the three sub- 

 genera mentioned above in the Hantkenininae, family 

 Nonionidae, apparently following Galloway's earlier 

 suggestion. 



Wood (1949, p. 250) showed that Hantkenina is per- 

 forate radial in wall structure (like the Globigerinidae 

 and Heterohehcidae), whereas the Nonionidae were per- 

 forate granular (exclusive of the Elphidiidae, which 

 Cushman placed in the Nonionidae). Therefore, 

 Hantkenina and its allies cannot be related to the Non- 

 ionidae, and the planispiral development of the two 

 famflies is merely convergence. It is more probable 

 that this group arose from the Planomalininae or the 

 early Globorotaliidae, for Schackoina, developing in the 

 Cretaceous, was trochospiral. The entire family Hant- 

 keninidae may have been derived from an ancestor such 

 as Praeglobotruncana of the Globorotaliidae, since many 

 lines of evolution point to a development of planispiral 

 forms from the trochospiral, rather than the converse. 



