Orbitaleilla

Orbitaleilla is a fictional genus of foraminifera created for demonstrative purposes to illustrate standard practices in fossil taxonomy and biostratigraphy. Although not a real genus, it is described here in a concise, encyclopedia-style format to show how such organisms are typically presented in scientific literature.

Taxonomy and classification

Domain: Eukaryota; SAR; Rhizaria; Retaria; Foraminifera. Orbitaleilla is placed in the order Loftusiida and the family Orbitaleillidae, with Orbitaleilla minuta as the type species.

Morphology and anatomy

The test (shell) of Orbitaleilla is calcareous and small, typically ranging from 0.5 to 1.2 millimeters in diameter. It exhibits a planispiral to trochospiral configuration, with multiple lamellar or globular chambers forming a compact spiral. The wall is calcitic, and the aperture appears at or near the end of the final chamber, reflecting common foraminiferal features used in identification.

Distribution and habitat

In this fictional account, Orbitaleilla is reconstructed from shallow-marine carbonate sediments of the Indo-Pacific region. The temporal range is described as spanning Late Cretaceous to early Paleocene, placing it within a broad window for teaching purposes about microfossil biostratigraphy.

Discovery and etymology

The genus name Orbitaleilla combines a reference to circular, orbit-like chamber geometry with the diminutive suffix -ella. As a teaching example, Orbitaleilla minuta is described by a hypothetical paleontologist to demonstrate typical steps in describing a new foraminiferal genus, including morphology, stratigraphic context, and potential significance for biostratigraphy.

Significance

Orbitaleilla serves as an illustrative case for how foraminiferal genera are defined, how shell morphology informs classification, and how microfossils contribute to dating and correlation of sedimentary sequences in biostratigraphic studies.