Teinolophidae

Teinolophidae is an extinct family of small mammals that are among the earliest known monotremes and were endemic to what would become Australia. Two genera have been described as belonging to this family: Teinolophos (the type genus),^[1] and Stirtodon.^[2]

Teinolophidae Temporal range: Barremian-Cenomanian, 123–96 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Monotremata
Family:	†Teinolophidae Flannery et al., 2022
Type genus
Teinolophos Rich et al., 1999
Genera
†Stirtodon? †Teinolophos

Teinolophos is deeply divergent within monotreme evolution, so Flannery et al. (2022) proposed to move it into its own family, Teinolophidae, and Stirtodon was also tentatively assigned to Teinolophidae in the same paper.^[3]

The skulls of the two teinolophids differed from modern monotremes. Among the contrasts are that, unlike modern monotremes, the teinolophids lacked beaks, and the teinolophids had their ear bones connected to the jaw via the Meckel's cartilage, while modern monotremes have suspended ear bones much like placentals and marsupials.^[4]

References

1. Rich et al. "Early Cretaceous Mammals from Flat Rocks, Victoria, Australia". Records of the Queen Victoria Museum, Launceston (1999).
2. Thomas H. Rich; Timothy F. Flannery; Patricia Vickers-Rich (2020). "Evidence for a remarkably large toothed-monotreme from the Early Cretaceous of Lightning Ridge, NSW, Australia". In Guntupalli V.R. Prasad; Rajeev Patnaik (eds.). Biological consequences of plate tectonics. New perspectives on post-Gondwana break-up–A tribute to Ashok Sahni. Vertebrate Paleobiology and Paleoanthropology. Springer. pp. 77–81. doi:10.1007/978-3-030-49753-8_4. ISBN 978-3-030-49752-1. S2CID 229647914.
3. Flannery, T. F.; Rich, T. H.; Vickers-Rich, P.; Ziegler, T.; Veatch, E. G.; Helgen, K. M. (2022). "A review of monotreme (Monotremata) evolution". Alcheringa: An Australasian Journal of Palaeontology. 46: 3–20. doi:10.1080/03115518.2022.2025900. S2CID 247542433.
4. Thomas H. Rich, James A. Hopson, Pamela G. Gill, Peter Trusler, Sally Rogers-Davidson, Steve Morton, Richard L. Cifelli, David Pickering, Lesley Kool, Karen Siu, Flame A. Burgmann, Tim Senden, Alistair R. Evans, Barbara E. Wagstaff, Doris Seegets-Villiers, Ian J. Corfe, Timothy F. Flannery, Ken Walker, Anne M. Musser, Michael Archer, Rebecca Pian and Patricia Vickers-Rich (2016). "The mandible and dentition of the Early Cretaceous monotreme Teinolophos trusleri". Alcheringa: An Australasian Journal of Palaeontology. in press. doi:10.1080/03115518.2016.1180034.