Haynes (1981) distinguished Jenkinsina from Guembelitria based on the absence of pore mounds. In a study of Paleogene triserial planktonic foraminifera, Jenkins and others (1998) supported this distinction with SEM images of well-preserved specimens of both genera. Although Loeblich and Tappan (1988) considered Jenkinsina to be a junior synonym of Chiloguembelitria Hofker (1978) based on SEM observation of topotypes of the type species of both genera (the primary type specimens have been lost), further SEM study of topotype material led Jenkins and others (1998) to conclude that the type species of Chiloguembelitria, C. danica Hofker (1978), does have pore mounds and therefore is not synonymous.
SEM observation of the shell microstructure of a well preserved specimen of Jenkinsina columbiana (Pl. 16.1, Figs. 10-11) reveals that it has a monolamellar wall. This seems to be a consistent feature of the microperforates, as it has been observed in Guembelitria cretacea and several species of Tenuitella.
[Huber et al. 2006]