The species name honours the artist Peter Trusler. The genus name, Teinolophos, means "extended ridge", a reference to its tooth structure.
Originally, Teinolophos was thought to be a eupantothere. Further research revealed similarities to Steropodon, except in size: the animal was around 10 cm long. It is often listed as a steropodontid, though it may be more basal.[1]Teinolophos is deeply divergent within monotreme evolution, so in 2022 it was proposed to move it into its own family, Teinolophidae. Stirtodon may be a close relative of Steropodon within Teinolophidae.[2]
The holotype is a partial left dentary known as NMV P208231. An age of approximately 123 million years makes this the earliest known monotreme. The lower molar is broadly similar in morphology to the m2 of Steropodon. The trigonid is compressed and the talonid has no basin. The dentary is about one sixth the size of Steropodon's, and wear facets indicate an "orthal" occlusion with the upper molars.
The construction of the lower jaw differs from existing monotremes. Among the contrasts are the condyle, which is well above the tooth row (instead of at about the same height); and the ascending ramus, which is also higher. Also different is that Teinolophos probably had a strong bite. A unique feature for known toothed monotremes is that the trigonid is tall, while the talonid is set much lower. This is more like the general mammalian arrangement. The molar is double-rooted, which is plesiomorphic when compared to ornithorhynchids, but is a shared characteristic with Steropodon and Kollikodon. Subsequent monotreme molars are multi-rooted.
Unlike modern monotremes, Teinolophos lacked a beak.[1]
Earsedit
Unlike modern monotremes, which have suspended ear bones much like placentals and marsupials, Teinolophos still had them connected to the jaw via the Meckel's cartilage. This reinforces the idea that the modern ear condition evolved independently among monotremes and therians.[1]
Evolutionedit
One study interpreted Teinolophos as a basal platypus.[3]
^ abcThomas 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.
^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.
^Rowe, T., Rich, T. H., Vickers-Rich, P., Springer, M., & Woodburne, M. O. (2008). The oldest platypus and its bearing on divergence timing of the platypus and echidna clades. Proceedings of the National Academy of Sciences, 105(4), 1238-1242. doi:10.1073/pnas.0706385105
Bibliographyedit
Rich et al. "Early Cretaceous Mammals from Flat Rocks, Victoria, Australia". Records of the Queen Victoria Museum, Launceston (1999).
Rich, T. H., et al. "Monotreme nature of the Australian Early Cretaceous mammal Teinolophos". Acta Palaeontologica Polonica46(1). 2001 Pages 113–118.
Rowe, T., et al. "The oldest platypus and its bearing on divergence timing of the platypus and echidna clades". Proceedings of the National Academy of Sciences105(4). 2008 Pages 1238–1242.
External linksedit
Wikispecies has information related to Teinolophos.
Life in the Shadows, Non-reptilian life in Mesozoic Australia
"Prehistoric jawbone reveals evolution repeating itself" 10 February 2005
"The oldest platypus and its bearing on divergence timing of the platypus and echidna clades" 2008
March 17, 2024
teinolophos, this, article, includes, list, general, references, lacks, sufficient, corresponding, inline, citations, please, help, improve, this, article, introducing, more, precise, citations, april, 2012, learn, when, remove, this, template, message, prehis. This article includes a list of general references but it lacks sufficient corresponding inline citations Please help to improve this article by introducing more precise citations April 2012 Learn how and when to remove this template message Teinolophos is a prehistoric species of monotreme or egg laying mammal from the Teinolophidae It is known from four specimens each consisting of a partial lower jawbone collected from the Wonthaggi Formation at Flat Rocks Victoria Australia It lived during the late Barremian age of the Lower Cretaceous TeinolophosTemporal range Late Barremian 123 Ma PreꞒ Ꞓ O S D C P T J K Pg N Scientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClass MammaliaOrder MonotremataFamily TeinolophidaeGenus TeinolophosSpecies T trusleriBinomial name Teinolophos trusleriRich et al 1999The species name honours the artist Peter Trusler The genus name Teinolophos means extended ridge a reference to its tooth structure Originally Teinolophos was thought to be a eupantothere Further research revealed similarities to Steropodon except in size the animal was around 10 cm long It is often listed as a steropodontid though it may be more basal 1 Teinolophos is deeply divergent within monotreme evolution so in 2022 it was proposed to move it into its own family Teinolophidae Stirtodon may be a close relative of Steropodon within Teinolophidae 2 The holotype is a partial left dentary known as NMV P208231 An age of approximately 123 million years makes this the earliest known monotreme The lower molar is broadly similar in morphology to the m2 of Steropodon The trigonid is compressed and the talonid has no basin The dentary is about one sixth the size of Steropodon s and wear facets indicate an orthal occlusion with the upper molars Contents 1 Description 1 1 Jaw 1 2 Ears 1 3 Evolution 2 See also 3 References 3 1 Bibliography 4 External linksDescription editJaw edit The construction of the lower jaw differs from existing monotremes Among the contrasts are the condyle which is well above the tooth row instead of at about the same height and the ascending ramus which is also higher Also different is that Teinolophos probably had a strong bite A unique feature for known toothed monotremes is that the trigonid is tall while the talonid is set much lower This is more like the general mammalian arrangement The molar is double rooted which is plesiomorphic when compared to ornithorhynchids but is a shared characteristic with Steropodon and Kollikodon Subsequent monotreme molars are multi rooted Unlike modern monotremes Teinolophos lacked a beak 1 Ears edit Unlike modern monotremes which have suspended ear bones much like placentals and marsupials Teinolophos still had them connected to the jaw via the Meckel s cartilage This reinforces the idea that the modern ear condition evolved independently among monotremes and therians 1 Evolution edit One study interpreted Teinolophos as a basal platypus 3 See also editMonotreme Fossil monotremesReferences edit a b c 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 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 Rowe T Rich T H Vickers Rich P Springer M amp Woodburne M O 2008 The oldest platypus and its bearing on divergence timing of the platypus and echidna clades Proceedings of the National Academy of Sciences 105 4 1238 1242 doi 10 1073 pnas 0706385105 Bibliography edit Rich et al Early Cretaceous Mammals from Flat Rocks Victoria Australia Records of the Queen Victoria Museum Launceston 1999 Rich T H et al Monotreme nature of the Australian Early Cretaceous mammal Teinolophos Acta Palaeontologica Polonica 46 1 2001 Pages 113 118 Rowe T et al The oldest platypus and its bearing on divergence timing of the platypus and echidna clades Proceedings of the National Academy of Sciences 105 4 2008 Pages 1238 1242 External links edit nbsp Wikispecies has information related to Teinolophos Life in the Shadows Non reptilian life in Mesozoic Australia Mesozoic Mammals Monotremata an Internet directory Prehistoric jawbone reveals evolution repeating itself 10 February 2005 The oldest platypus and its bearing on divergence timing of the platypus and echidna clades 2008 Retrieved from https en wikipedia org w index php title Teinolophos amp oldid 1167352912, wikipedia, wiki, book, books, library,
