Yalkaparidon coheni

Overview

Yalkaparidon coheni is a metatherian known from skull and tooth material from Riversleigh, Australia. Its reference specimen includes a skull and an associated partial lower jaw. Even small tooth positions helped distinguish it from a closely related species.^[1]

Key facts

A redescription concluded that the two species were difficult to distinguish by size alone. The presence of tooth sockets between the first lower incisor and first molar was used as a criterion for assignment to coheni.^[1]

Time and place

Oligocene and Miocene material from Riversleigh in present-day Australia has been studied. The broad combined time window of these two epochs is approximately 34–5.3 million years ago. Skull and tooth material provides clues to identifying this ancient metatherian.^[1][2]

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

Size, form and skeleton

The reference specimen QM F13008 includes a skull and a partial right lower jaw. Tooth positions between the incisor and molar in the jaw were used to compare species. The whole head and its tiny tooth sockets can be examined at different scales.^[1]

The combined head-and-body length of Yalkaparidon coheni is described as approximately 20 cm. This measurement excludes the tail and provides a reference for imagining the size of this small marsupial.^[3]

Habitat and reproduction

What functions might animals of the same genus have performed? Researchers provisionally assigned isolated ankle bones to Yalkaparidon and compared joint movement. This explores questions of lifestyle using material different from the skull and teeth studied for coheni.^[1]

Fossil discovery

The redescription by Beck and colleagues examined the skull and lower jaw of the reference specimen in detail and considered criteria for distinguishing two species. Isolated ankle bones were discussed separately as provisional genus-level material. Different bones addressed different questions about form and function.^[1]

References

1. Beck et al. — Osteology and classification of the enigmatic metatherian Yalkaparidon
2. International Commission on Stratigraphy (2024) — Geological time chart
3. Australian Museum — Yalkaparidon coheni
4. 1999 study — Barinya from Riversleigh

Research questions

How can two species with overlapping sizes be distinguished? Research on Yalkaparidon examined the arrangement of tooth sockets preserved in the jaw. Even without large size differences, the arrangement of small features can help compare species.^[1]

Observation

Move your gaze from the head to the lower jaw. Imagining the tooth positions between the first lower incisor and first molar lets you examine the entire head alongside small diagnostic features.^[1]