Ben Creisler
New short papers with free pdfs:
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Julien Benoit (2019)
Parental care or opportunism in South African Triassic cynodonts?Â
South African Journal of Science 115(3/4): Art. #5589
Free pdf:
In a paper published in Nature in 2018, Hoffman and Rowe describe the discovery of an adult tritylodontid cynodont, Kayentatherium, from the Jurassic of the Kayenta Formation (Arizona, USA), accompanied by at least 38 perinatal juveniles, all at the same very early stage of development. Such a high number of juveniles in one clutch is found only in a handful of oviparous reptiles, and never in viviparous or ovoviviparous species1, suggesting that these cynodonts laid eggs. As tritylodontids are amongst the closest relatives to Mammaliaformes, and sometimes even reconstructed as their sister clade, this textbook changing discovery implies that all non-mammaliaform synapsids had an essentially reptilian-like reproductive biology.
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J. Francis Thackeray (2019)
Alpha and sigma taxonomy of Lystrosaurus murrayi and L. declivis, Triassic dicynodonts (Therapsida) from the Karoo Basin, South Africa.
South African Journal of Science 115(3/4): Art. #a0296
Free pdf:
Excerpt:
On the basis of an impressive sample of almost 200 crania of Triassic Lystrosaurus studied by Botha-Brink et al., it has been demonstrated that the mean basal skull length of specimens attributed to L. murrayi is not significantly different from the mean basal skull length dimension of specimens attributed to L. declivis. The mean values (and the associated standard deviations) are almost identical, as if one species was being sampled from the same kind of populations. In addition to the morphometric data presented here, based on as many as 20 variables per specimen, this result is relevant to the possibility that no distinct boundary exists between the two taxa at a species level, in the context of both temporal and spatial variability.
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