Origolestes (Early Cretaceous mammal) cranial and middle ear structure (free pdf)
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Ben Creisler
Dec 23, 2025, 2:37:26 PM12/23/25
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Ben Creisler
A new paper:
Zhe-Xi Luo, Chang-Fu Zhou, Peishu Li & April I. Neander (2025)
Cranial and middle ear structures of the Early Cretaceous mammal Origolestes (Spalacotherioidea, Trechnotheria, Mammalia)
Palaeobiodiversity and Palaeoenvironments (advance online publication)
doi: https://doi.org/10.1007/s12549-025-00683-0
https://link.springer.com/article/10.1007/s12549-025-00683-0
In this study we offer a new analysis of the internal cranial structures and the middle ear of the Early Cretaceous spalacotherioid mammal Origolestes lii, from the Yixian Formation of Liaoning, China. This anatomical study is based on CT scanning of a three-dimensionally preserved skull of this taxon. Spalacotherioid mammals are a group in the trechnotherian clade that includes modern therians such as marsupials and placentals. Fossils of these Mesozoic stem therians can yield useful information on the evolutionary origin of modern therian traits. Because cranial fossils of Mesozoic stem therians in three-dimensional preservation are scarce, and also because the internal cranial structures used to be difficult to examine, before CT scanning of fossils became available, the internal cranial structure was rarely documented in detail. Our CT scanning and visualisation of the skull of Origolestes lii have revealed new anatomical information of the orbital and sphenoid regions of the braincase, for this group. This is helpful for interpreting the comparative morphology of the skull structure among Mesozoic mammals. Furthermore, this specimen is a rare fossil in that it has preserved the petrosal articulation of the incus, as well as the Meckelian-attached middle ear. Evidence from our CT rendering and digital re-articulation demonstrates that a connection of the malleus to the ossified Meckel’s cartilage still existed in Origolestes lii.
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Free pdf:
Zhe-Xi Luo, Chang-Fu Zhou, Peishu Li & April I. Neander (2025)
Cranial and middle ear structures of the Early Cretaceous mammal Origolestes (Spalacotherioidea, Trechnotheria, Mammalia)
Palaeobiodiversity and Palaeoenvironments (advance online publication)
doi: https://doi.org/10.1007/s12549-025-00683-0
https://link.springer.com/article/10.1007/s12549-025-00683-0
In this study we offer a new analysis of the internal cranial structures and the middle ear of the Early Cretaceous spalacotherioid mammal Origolestes lii, from the Yixian Formation of Liaoning, China. This anatomical study is based on CT scanning of a three-dimensionally preserved skull of this taxon. Spalacotherioid mammals are a group in the trechnotherian clade that includes modern therians such as marsupials and placentals. Fossils of these Mesozoic stem therians can yield useful information on the evolutionary origin of modern therian traits. Because cranial fossils of Mesozoic stem therians in three-dimensional preservation are scarce, and also because the internal cranial structures used to be difficult to examine, before CT scanning of fossils became available, the internal cranial structure was rarely documented in detail. Our CT scanning and visualisation of the skull of Origolestes lii have revealed new anatomical information of the orbital and sphenoid regions of the braincase, for this group. This is helpful for interpreting the comparative morphology of the skull structure among Mesozoic mammals. Furthermore, this specimen is a rare fossil in that it has preserved the petrosal articulation of the incus, as well as the Meckelian-attached middle ear. Evidence from our CT rendering and digital re-articulation demonstrates that a connection of the malleus to the ossified Meckel’s cartilage still existed in Origolestes lii.
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