Calpionella alpina

Overview

Calpionella alpina is a protist studied through a small fossil shell called a lorica. Its rounded body and short neck-like region stand out. This tiny outline connects with comparisons of the ages of rock layers.^[1]

Key facts

Calpionellids are important fossils for correlating the ages of distant rock layers. Changes in their small body forms and their wide distributions help connect rock records across regions.^[1]

Time and place

The material in this study came from the Early Cretaceous Padhi section in present-day Hidalgo, Mexico. It is recorded in limestone at horizon CEP-1.005, allowing tiny fossils to be traced within a specific rock layer.^[1]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

The lorica is spherical to nearly spherical, with a short cylindrical collar distinct from the body. The opposite end is slightly angular and lacks a long, tail-like projection.^[1]

The shell described in this study is approximately 60 µm long. This is approximately 0.06 mm, a size examined under a microscope.^[2]

The shell width reported in the same study is approximately 50 µm.^[2]

Habitat and reproduction

The studied strata are associated with a deep-marine basin depositional environment. Calpionellids, small bivalve fragments, and occasional sponge spicules in limestone are examined together to understand the ancient sea.^[1]

Fossil discovery

Lorenz described Calpionella alpina in 1902. Research on the Padhi section in Mexico compared several calpionellids and reassessed this species’ form and fossil-bearing horizons.^[1]

References

1. Study of the Padi section — Morphology and strata of Calpionella alpina
2. Calpionélidos de la transición Berriasiano-Valanginiano en la Sección Padhi, centro-este de Hidalgo, México: sistemática y bioestratigrafía
3. Nakkady (1950) — Transcription of the original description of Globotruncana aegyptiaca
4. Mikrotax — Stratigraphic distribution of Globotruncana

Research questions

The same fossil can look different in an oblique section. To distinguish forms resembling Calpionella elliptica, researchers compare both outlines and the rock layers in which they occur.^[1]

Observation

In the illustration, examine the connection between the rounded lorica and the short collar. Follow the difference between the collar end and the opposite end to read the orientation of this small form.^[1]