3D skull modelling and description of a new baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the Late Cretaceous (Bauru Basin) of Brazil

Abstract

Baurusuchidae is one of the most diverse groups of South American notosuchians, unambiguously recorded in Late Cretaceous deposits of Brazil and Argentina. The group is characterized by a reduced tooth formula, a lateromedially compressed rostrum, and a verticalized quadrate, representing one of the top predators of their faunas. Historically, skull morphology is the most employed tool to investigate the relationships of baurusuchids, as most of the species have been primarily based on cranial remains. The present study describes a new baurusuchid species from the Bauru Basin of Brazil, based on the first tridimensional digital reconstruction of individualized skull bones for Notosuchia, and discusses its phylogenetic position within the group. The new species differs from all the other known baurusuchids by a depression on the posterior portion of the nasal bearing a crest, an infraorbital crest of the jugal that extends until the anterior margin of the lacrimal, the dorsal surface of the frontal lacking a longitudinal crest or depression, and the lateral convexity of the squamosal prongs participating in the occipital wall. The new taxon is consistently positioned as sister to the remaining baurusuchines, with Aplestosuchus sordidus and Stratiotosuchus maxhechti, as successive sister‐taxa to a monophyletic Baurusuchus (Ba. albertoi, Ba. Salgadoensis, and Ba. pachecoi). Our updated phylogenetic analysis helps to differentiate the two major Baurusuchidae lineages, Baurusuchinae and Pissarrachampsinae. Yet, the new species shares morphological features with both groups, suggesting the occurrence of “Zones of Variability” in the radiation of Baurusuchidae.

A second peirosaurid crocodyliform from the Mid-Cretaceous Kem Kem Group of Morocco and the diversity of Gondwanan notosuchians outside South America

“…Characters with missing entries were downweighted faster assuming 50% of the homoplasy of observed entries, and weighting strength did not exceed 5 times that of characters with no missing entries. Forty-three characters representing nested sets of homologies were ordered (1,3,6,10,23,37,43,44,45,49,65,67,69,71,73,77,79,86,90,91,96,97,105,116,126,140,142,143,149,167,182,187,193,197,226,228,279,339,356,357,364,368,401). Character 5 was made inactive due to 'dependence with the modified definition of character 6' ( [6]: supplementary information, p. 3).…”

“…[25,60,76,85,103,105,117]), which is otherwise known only from South America (e.g. [142,143]). By contrast, Larsson & Sues [46] recovered Pabwehshi as the most 'basal' member of Sebecia, i.e.…”

“…Buffetaut [102] erected Eremosuchus elkoholicus from the El Kohol Formation of southwest Algeria (figure 12), which is dated to the Ypresian, early Eocene [142]. This species is known from a partial mandible, teeth, vertebrae and a fibula.…”

Palate evolution in early‐branching crocodylomorphs: Implications for homology, systematics, and ecomorphology

“…The medial sutures between the palatines of all crocodylomorph taxa with secondary palates are interdigitated, but in general, the suture is level with the surface of the palate. In Shartegosuchus and in nearly all baurusuchids (Darlim et al, 2021) where this region is preserved (excluding Cynodontosuchus rothi and Gondwanasuchus scabrosus), the suture is strongly interdigitated and thickened so that it forms a raised ridge that extends along the entire length of the contact (Figure 3d). This is amended here from its original description to clarify the palatal suture is reinforced.…”

Ultrasonography, Microcomputed Tomography, and Macroscopic Preparation in an Anatomical Study of the Thoracic Limb of the Golden-Headed Lion Tamarin (Leontopithecus chrysomelas)

“…Threedimensional computer models, simulations of biomechanics of movement, and series of images from different cross-sections make it possible to present anatomy in a wide range of non-invasive ways. CT is often used to analyse the skeletal system [11,12], whereas ultrasonography is used for soft tissues such as muscles [13][14][15][16]. However, many authors of anatomical studies still use traditional methods, which involve the preparation of dead tissues [17,18].…”