Nomenclature to describe the transition from multiserial to uniserial chamber arrangement in benthic foraminifera

摘要

We define terms used to describe the transition from a trochospiral, multiserial or biserial chamber arrangement to a uniserial chamber arrangement in benthic foraminifera. The morphological transition from a trocho-, multi- or biserial to a uniserial chamber arrangement may be abrupt, or form a morphological progression through transitional stages defined as 'loosely biserial', `lax-uniserial' and, finally, 'loosely uniserial'. The precise meanings of the intermediate stages ending in uniseriality are defined here by means of examples using foraminiferal models. We introduce the new terms 'Cryptobiserial', 'Cryptotriserie and `Cryptotrochospiral' to describe the chamber arrangement in genera with uniserial stages that preserve the sense of coiling of the previous trochospiral, triserial or biserial stages.