Imagotaria downsi

Overview

Imagotaria downsi is a fossil pinniped known from features of the skull, teeth, and bones around the ear. Researchers also compared its structures with sea lions. Questions can begin in small parts of the head rather than the outline of a large body.^[1]

Key facts

Research specimen lists include LACM144453, a cast of the type specimen, alongside separate USNM specimens. Original fossils and casts provide different means of comparing form.^[2]

Time and place

Recorded fossil-bearing layers are summarized as Miocene material from approximately 12–7.2 million years ago. Skull and tooth descriptions and specimen lists in later research form the basis for understanding this animal.^[1][2][3]

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

Size, form and skeleton

The author’s abstract describes features of the skull, teeth, and bones around the ear. Examining different head regions separately allows the information supplied by each structure to be compared. Structural comparisons with related pinnipeds are also discussed.^[1]

A total body length of about 2.5 m is reported for Imagotaria downsi. This literature value compiled by a 2024 comparative study of marine organisms conveys the large size of an ancient walrus relative.^[4]

Habitat and reproduction

What different questions arise from teeth and bones around the ear? One provides clues to jaw organization, the other to the forms of internal head organs. Even within one head, the information varies with the region examined.^[1]

Fossil discovery

Mitchell’s 1968 abstract introduced the skull and teeth of Imagotaria. The examined-specimen list of a 2018 study includes a cast of the type specimen and separate fossils. An older description thus continues into new specimen comparisons.^[1][2]

References

1. Mitchell (1968) — The skull and teeth of Imagotaria
2. 2018 study of fossil walruses — A specimen list for Imagotaria
3. Paleobiology Database — Age of fossil-bearing strata of Imagotaria
4. Pimiento et al. (2024) — Extinct large marine organisms of the Phanerozoic
5. Field Museum — The body of Puijila
6. Rybczynski et al. (2009) — Puijila, an early Arctic relative of pinnipeds

Research questions

How are an original specimen and its cast used in research? Material representing the name-bearing reference can be compared alongside other fossils. Following specimen lists connects several records of the same animal.^[2]

Observation

Move your gaze from the teeth to the bones around the ear. Considering different regions within the same head helps compare pinniped form.^[1]