- Teinolophos
Taxobox
name = "Teinolophos"
fossil_range =Early Cretaceous
regnum =Animal ia
phylum = Chordata
classis =Mammal ia
ordo = Monotremata
familia=Steropodontidae
genus = "Teinolophos"
species = "T. trusleri"
binomial = "Teinolophos trusleri"
binomial_authority = Rich et al., 1999"Teinolophos trusleri" was a
prehistoric species ofmonotreme , or egg-layingmammal . It is known from a lower jawbone found in Flat Rocks, Victoria,Australia . It lived during theAptian age of the LowerCretaceous .The
species name honours the artistPeter Trusler . Thegenus name, "Teinolophos", means 'extended ridge', a reference to its tooth structure.Originally, "Teinolophos" was thought to be a
eupanthothere . Further research revealed similarities to "Steropodon ", except in size: the animal was around 10 cm long.The
holotype is a partial leftdentary 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 ascendingramus , 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 isplesiomorph ic when compared to ornithorhynchids, but is a shared characteristic with "Steropodon" and "Kollikodon ". Subsequent monotreme molars are multi-rooted.The species has been placed in the
Steropodontidae in some classifications.ee also
*Fossil Monotremes
Links and References
* 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.
* [http://www.alphalink.com.au/~dannj/non-rept.htm Life in the Shadows, Non-reptilian life in Mesozoic Australia]
* [http://home.arcor.de/ktdykes/monotrem.htm Mesozoic Mammals: Monotremata, an Internet directory]
* [http://www.eurekalert.org/pub_releases/2005-02/uocm-pjr020805.php "Prehistoric jawbone reveals evolution repeating itself"] 10 February 2005
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