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[dinosaur] Downsizing dicynodont Lisowicia + Francemys, new Cretaceous turtle from Niger

Ben Creisler

New non-dino papers:

Marco Romano & Fabio Manucci (2019)
Resizing Lisowicia bojani: volumetric body mass estimate and 3D reconstruction of the giant Late Triassic dicynodont.
Historical Biology (advance online publication)
doi: https://doi.org/10.1080/08912963.2019.1631819 Â

Body size is one of the most crucial biological properties, with a major influence on ecology, metabolism and several physiological aspects. Recently the exceptionally large dicynodont Lisowicia bojani from the Late Triassic of Poland has been described. Using a regression formula based on long bone circumferences, an impressive body mass of 9.33 tons was reconstructed in the original description for this new and largest member of dicynodonts. The taxon is characterized by particularly robust long bones with very massive and stout shafts, thus raising the theoretical possibility that the regression formulae may have led to a substantial overestimate of the body mass. Here we present a new body mass estimate for Lisowicia based on 3D digital volumetric models, aiming to provide a more reliable and conservative estimate. The new body mass ranges from 4.87 tons to 7.02 tons for the adult taxon, with an average body mass of 5.88 tons; thus, the original value of 9.33 tons overestimates the weight of about 60%. Our study confirms empirically that volumetric methods for body mass estimates should be preferred and implemented whenever possible. Synapsids still had to wait until the Eocene to reach the enormous body mass of 9 tons.


Free pdf:

Francemys gadoufaouaensis gen. et sp. nov.Â

A.PÃrez-GarcÃa (2019)
The African Aptian Francemys gadoufaouaensis gen. et sp. nov.: new data on the early diversification of Pelomedusoides (Testudines, Pleurodira) in northern Gondwana.
Cretaceous Research (advance online publication)
doi: https://doi.org/10.1016/j.cretres.2019.06.003

One of the two lineages that constitute the crown group Testudines, Pan-Pleurodira, experienced an important radiation during the Early Cretaceous, from the Barremian or earlier. The origin of the two lineages that form the crown Pleurodira (i.e. Pan-Chelidae and Pelomedusoides) is related to this radiation. Pelomedusoides diversified in northern Gondwana in a relatively short period of geological time. The African Aptian fossiliferous region of Gadoufaoua (central Niger) is one of the most interesting fossiliferous areas for the study of the early diversity and evolution of Pelomedusoides, this being where the oldest African identification of the synchronic and sympatric presence of several pleurodiran taxa is recognised. At least two lineages of Pelomedusoides are represented in Gadoufaoua, one being the extinct Araripemydidae. The second lineage had been recognised as related to Pelomedusidae or Podocnemidoidea, both clades representing part of the current biodiversity. A form from Gadoufaoua, hitherto poorly known and preliminarily presented almost 40 years ago, and currently determined as aff. Platycheloides sp., belongs to this second lineage. Its detailed study is performed here. It is defined as Francemys gadoufaouaensis gen. et sp. nov., constituting one of the few nominated pan-pleurodiran taxa (i.e., about a dozen species) currently recognised in the Lower Cretaceous record. It is identified as being closely related to Podocnemidoidea, the clade that groups the common ancestor and all of the descendants of the abundant and diverse extinct bothremydids and extant podocnemidids.

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