Nothosaurus mirabilis

Overview

Nothosaurus mirabilis was a Middle Triassic reptile. Comparative genus-level material describes a long, flattened skull, broad forelimbs, and a slender femur. Several body regions are understood through specimens and comparative studies.^[2][1]

Key facts

UMO1000 is described as preserving neck and back vertebrae, part of the tail, and limb bones. Even material that has lost its skull allows the trunk and limbs to be studied.^[2]

Time and place

The species’ type specimen is studied in an Anisian, Middle Triassic occurrence context. The Triassic as a whole spans approximately 250–200 million years ago. Comparative genus research and species redescription convey different evidence.^[2][3]

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

Size, form and skeleton

Genus-level accounts describe eyes and nostrils positioned on the upper surface of a long, flattened skull. Forelimbs are described as broad and the femur as slender. In the species’ type specimen, several vertebral regions and limb bones can be compared.^[1][2]

Type specimen UMO 1000 of Nothosaurus mirabilis was not yet fully grown. A 2022 study reconstructed a body length of at least about 2.9–3.2 m by restoring the missing skull and portions of the spine and tail.^[4]

Habitat and reproduction

How did the head, forelimbs, and hind limbs differ in construction? Genus-level evidence separately describes the flattened skull, broad forelimbs, and slender hind limb bones. This approach divides a large body into regions for comparison.^[1]

Fossil discovery

After a 2019 comparative study of nothosaurs, the mirabilis type specimen was redescribed in 2022. Researchers discussed the vertebral and limb material surviving in UMO1000 and its incompletely grown state. It is a renewed reading of an old specimen.^[2][1]

References

1. Voeten·Albers·Klein (2019) — Body comparison of nothosauroids
2. Klein·Eggmaier·Hagdorn (2022) — Redescription of the type specimen of Nothosaurus mirabilis
3. International Commission on Stratigraphy (2024) — Geological time chart
4. Klein et al. (2022) — Redescription of the type specimen of Nothosaurus mirabilis
5. Maidment et al. (2020) — Postcranial bones of Garjainia

Research questions

What more can an old type specimen reveal through redescription? Bone positions and growth status can be compared again. Nothosaurus illustrates how shared genus features and species-specific specimens provide different information.^[2][1]

Observation

Imagine the overall flattened head, then move your gaze to neck and trunk vertebrae and the forelimbs and hind limbs. Distinguishing which regions are known in each source helps compare different body features.^[2][1]