A new elasmosaurid from the early Maastrichtian of Angola and the implications of girdle morphology on swimming style in plesiosaurs
Authors:
Araújo et al
Abstract:
We report here a new elasmosaurid from the early Maastrichtian at Bentiaba, southern Angola. Phylogenetic analysis places the new taxon as the sister taxon to Styxosaurus snowii, and that clade as the sister of a clade composed of (Hydrotherosaurus alexandrae (Libonectes morgani + Elasmosaurus platyurus)). The new taxon has a reduced dorsal blade of the scapula, a feature unique amongst elasmosaurids, but convergent with cryptoclidid plesiosaurs, and indicates a longitudinal protraction-retraction limb cycle rowing style with simple pitch rotation at the glenohumeral articulation. Morphometric phylogenetic analysis of the coracoids of 40 eosauropterygian taxa suggests that there was a broad range of swimming styles within the clade.
Unexpectedly one of the largest diamond mines in Africa, Catoca in Angola, holds 118 million year old dinosaur, crocodile and large mammal tracks. The mammal tracks show a raccoon-sized animal, during a time when most were no larger than a rat.
Nearly 70 distinct tracks were recovered in the Catoca mine in Angola. All the tracks were found in a small sedimentary basin, formed about 118 Ma, during the Early Cretaceous, in the crater of a kimberlite pipe.
The most important of these finds are those whose morphology is attributable to a large mammalian trackmaker, the size of a modern raccoon. There is no evidence from bones or teeth of such a large Early Cretaceous mammal from Africa or elsewhere in the World. The most comparably sized mammalian skeleton is known from China, and is 4-7 Ma older than the Angolan tracks. It has an estimated head-body length between 42 and 68 cm, but because it is missing hands and feet, a comparison with the tracks from Catoca is not possible.
The mosasaur, a fearsome marine reptile that stalked the Cretaceous seas, scavenged its own kin, a new fossil find reveals.
A fossilized mosasaur found in Angola contains the partial remains of three other mosasaurs in its stomach, researchers reported here Tuesday (Oct. 29) at the annual meeting of the Geological Society of America.
"These are three different species of mosasaur inside the belly of a fourth species of mosasaur," said study researcher Louis Jacobs, a vertebrate paleontologist at Southern Methodist University in Texas.
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