Slimane Zitouni, Christian Laurent , Gareth Dyke &Â Nour-Eddine Jalil (2019)
An abelisaurid (Dinosauria: Theropoda) ilium from the Upper Cretaceous (Cenomanian) of the Kem Kem beds, Morocco.
PLoS ONE 14(4): e0214055.Â
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Abelisaurid theropods first appear in the fossil record in the early Jurassic and survived at least until the end of the Mesozoic. They were known to have dominated South America, India and Madagascar but were not so abundant in North America or Asia. Much less is known about their presence in Africa, although there has been several recent discoveries of abelisaurid material in Morocco. Here we add a partially preserved ilium to a growing body of evidence that suggests abelisaurs might also have dominated Africa.
Orvil Grunmeier and Michael D. D'Emic (2019)
Scaling of statically derived osteocyte lacunae in extant birds: implications for palaeophysiological reconstruction.
Biology Letters 15: 20180837.
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Osteocytes are mature versions of osteoblasts, bone-forming cells that develop in two ways: via 'static' osteogenesis, differentiating and ossifying tissue in situ to form a scaffold upon which other bone can form, or 'dynamic' osteogenesis, migrating to infill or lay down bone around neurovasculature. A previous study regressed the volume of osteocyte lacunae derived from dynamic osteogenesis (DO) of a broad sample of extant bird species against body mass, the growth rate constant (k), mass-specific metabolic rate, genome size, and erythrocyte size. There were significant relationships with body mass, growth rate, metabolic rate, and genome size, with the latter being the strongest. Using the same avian histological dataset, we measured over 3800 osteocyte lacunar axes derived from static osteogenesis (SO) in order to look for differences in the strength of formâfunction relationships inferred for DO-derived lacunae at the cellular and tissue levels. The relationship between osteocyte lacunar volume and body mass was stronger when measuring SO lacunae, whereas relationships between osteocyte lacunar volume versus growth rate and basal metabolic rate disappeared. The relationship between osteocyte lacuna volume and genome size remained significant and moderately strong when measuring SO lacunae, whereas osteocyte lacuna volume was still unrelated to erythrocyte size. Our results indicate that growth and metabolic rate signals are contained in avian DO but not SO osteocyte lacunae, suggesting that the former should be used in estimating these parameters in extinct animals.