The Foraminiferal Genus Cruciloculina d'Orbigny, 1839 



By Alfred R. Loeblich, Jr., and Helen Tappan ' 

 Introduction 



THE GENUS CrucUocvlina was described in 1839, and 

 d'Orbigny (1839b) later recorded a single species, C. 

 triangularis. Later workers did not recognize this 

 genus, however, considering it a sjTionjon of Trilocidina 

 d'Orbigny, in spite of the distinctive cruciform aperture. 

 A century later Asano (1949, p. 479) made a detailed 

 study of the apertural development of a second species, 

 Cruciloculina japonica, and emended the generic 

 diagnosis. The type species for the genus was from the 

 Recent seas off the Falkland Islands, and the species 

 described by Asano was from the Pliocene of Japan. 



During the course of generic studies of Foraminifera 

 for the "Treatise on Invertebrate Paleontology," the 

 writers examined d'Orbigny's types of Cruciloculina in 

 the Museum National d'Histoire Natm-elle in Paris. 

 A lectotype for this species is here selected, refigured, 

 and described. An additional topotype specimen of C. 

 triangularis has also been illustrated. 



A topotype specimen of C. japonica Asano from the 

 Japanese Pliocene is illustrated and a brief description 

 given for comparison. 



Three new Recent species of the genus are also here 

 described, two occurring in the Caribbean and the other 

 in the North Atlantic off southwestern Ireland. 



The ontogenetic apertiu-al development of all species 

 is similar to that described by Asano for C. japonica. 



The genus is thus fairly widespread in the Recent seas, 

 and in the future will probably be found more wide- 

 spread in fossil faunas as well. 



The writers are grateful to the Smithsonian Institu- 

 tion for making possible the visit of Alfred R. Loeblich, 

 Jr., to the Museum National d'Histoire Naturelle in 

 Paris, and to the John Simon Guggenheim Memorial 

 Foundation for a fellowship gi-ant to Helen Tappan 

 Loeblich, which thus made possible the restudy of the 

 d'Orbigny types. 



Grateful acknowledgment is given of the cooperation 

 of M. Jean Roger, Museum National d'Histoire Na- 

 turelle, Paris, France, in permitting the restudy and 

 reiUustration of the d'Orbigny type specimens. 



We are indebted to Dr. K. Asano, Institute of 

 Geology and Paleontology, Tohoku University, Sendai, 

 Japan, and to Mr. T. Uchio, Institute of Petroleum 

 Engineering, Tokyo University, Tokyo, Japan, for 

 furnishing us an excellent series of the species Cruci- 

 loculina japonica Asano from Japan. 



Systematic Descriptions 



Family Miliolidae d'Orbigny, 1839 



Genus Cruciloculina d'Orbigny, 1839 



Cruciloculina D'Orbigny, Foraminiftres in de la Sagra, Hist. 

 Phys., Polit. et Nat. de I'lle de Cuba, p. 182, 1839. 



Type species: Cruciloculina triangularis d'Orbigny, 

 1839. Fixed by subsequent monotypy by d'Orbigny 

 (1839b, p. 72). 



Test free, chambers coiled, with the longitudinal 

 planes of successive chambers added 120 degrees apart 

 as in the development of Triloculina, test rounded to 

 triangidar in section; sutures distinct, depressed; wall 

 calcareous, imperforate, smooth or faintly striate; 

 aperture complex, varying in shape from triradiate in 

 the young to cruciform or dendritic in the adult, bor- 

 dered by a narrow lip, but without a distinct tooth. 



Cruciloculina differs from Triloculina d'Orbigny in 

 the apertural features, lacking the distinct tooth of 

 Triloculina and developing from a simple linear, bifid 

 or triradial aperture in the young to a cruciform or 

 dendritic aperture in the adult. 



> Helen Tappan Loeblich, U. S. Qeologlcal Survey and Research Associate, Smith- 

 sonian Institution. 



This genus occurs in the Pliocene of Japan and in the 

 Recent in the North and South Atlantic and Caribbean. 



Cruciloculina asanoi Loeblich and Tappan, new species 

 Plate 74, Figubes 8-11 



Test free, triloculine in chamber development, ovate 

 in side view, subtriangular in section, angles rounded; 

 chambers with slight amount of overlap, so that those 

 in the final whorl appear nearly equal in size; sutures 

 distinct, slightly incised; wall calcareous, imperforate, 

 surface smooth, apcrtiu-e triradiate in young specimens, 

 becoming cruciform in the adult. 



Length of holotype 1.06 mm., thickness from center 

 of final chamber to opposite angle 0.94 mm. Para- 

 tjrpes range from 0.51 to 1.10 mm. in length. 



Remarks: This species is similar in appearance to 

 C. japonica Asano, but differs in the very slight amount 

 of chamber overlap, somewhat smaller size, and much 

 less complex adult aperture, that of C. asanoi becoming 

 only cruciform, whereas that of C. japonica may become 

 highly dendritic in appearance. 



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