A new crocodyliform from the Upper Cretaceous (Campanian-Maastrichtian) Presidente Prudente Formation of the Bauru Group is described based on two almost complete skulls and mandibles. The material comes from the "Tartaruguito" site, situated at an old railroad between the cities of Pirapozinho and Presidente Prudente, state of São Paulo, Brazil. The new species, Pepesuchus deiseae gen. et sp. nov., is classified in the clade Peirosauridae on the basis of three synapomorphies: the presence of five premaxillary teeth, the anterior two premaxillary alveoli nearly confluent, and the oval cross-section of the jugal along the lower temporal bar. The new taxon increases the outstanding crocodyliform diversity of the Bauru Group, particularly of the Peirosauridae, which might turn out to be one of the most representative clades of gondwanan mesoeucrocodylians.
A third specimen of Susisuchus anatoceps is described. The new material comprises postcranial remains, including an almost complete sequence of cervical vertebrae, prothoracic and posterior dorsal vertebrae, and osteoderms from dorsal and ventral shield, scapula, coracoid and the forelimb. The new specimen (MPSC‐R1136) was recovered from the Crato Formation (Lower Cretaceous) of the Santana Group, near Nova Olinda municipality, Ceará State, Brazil. Some cervical vertebrae show slightly procoelous centra and at least one of these vertebrae is platycoelic, a feature reported for the first time in Susisuchus. Nevertheless, dorsals have amphicoelic centra. The sagittal segmented dorsal shield comprises two paravertebral rows of square osteoderms and two accessory rows of ellipsoidal osteoderms on each side of the trunk. Three diagnostic characters are present in the new Susisuchus specimen: the proximal and distal articulations of the ulna have about the same width and are thicker with respect to the shaft; the scapular blade has posterior concave and anterior straight margins; and the ungual phalanges are present only on first and second digits of the manus. A phylogenetic analysis of Susisuchus anatoceps based on new characters of MPSC‐R1136 in addition to the holotype, and employing a previous data set of Jouve, placed this taxon as a basal member of the advanced neosuchian clade. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163, S273–S288.
Susisuchus anatoceps is a neosuchian crocodylomorph lying outside the clade Eusuchia, and associated with the transition between basal and advanced neosuchians and the rise of early eusuchians. The specimen MPSC R1136 comprises a partially articulated postcranial skeleton and is only the third fossil assigned to this relevant taxon. Thin sections of a right rib and right ulna of this specimen have been cut for histological studies and provide the first paleohistological information of an advanced non-eusuchian neosuchian from South America. The cross-section of the ulna shows a thick cortex with 17 lines of arrested growth (LAGs), a few scattered vascular canals, and primary and secondary osteons. This bone has a free medullary cavity and a spongiosa is completely absent. Thin sections of the rib show that remodeling process was active when the animal died, with a thin cortex and a well-developed spongiosa. In the latter, few secondary osteons and 4 LAGs were identified. According to the observed data, Susisuchus anatoceps had a slow-growing histological microstructure pattern, which is common in crocodylomorphs. The high number of ulnar LAGs and the active remodeling process are indicative that this animal was at least a late subadult, at or past the age of sexual maturity. This contradicts previous studies that interpreted this and other Susisuchus anatoceps specimens as juveniles, and suggests that full-grown adults of this species were relatively small-bodied, comparable in size to modern dwarf crocodiles.
The fossil fauna of the Santana Formation (Early Cretaceous) comprises many distinct taxa, but crocodylomorphs are poorly understood. Here we describe a new specimen (MPSC-R1137) that consists of a complete hind limb found in the Crato Member, the basal section of the Santana Formation. Based on the characteristics of the fibula (e.g., pronounced variation of the shaft width) and length proportions of the femur and tibia, this specimen can be distinguished from Caririsuchus camposi and Araripesuchus gomesii, which are known from the Romualdo Member (the upper lithostratigraphic unit of the Santana Formation). The only crocodylomorph formally described from the Crato Member is Susisuchus anatoceps, whose holotype lacks elements of the hind limb. On the basis of a comparative anatomical study of the hind limb, which shows no similarities between MPSC-R1137 and other crocodylomorphs from the Araripe Basin, we tentatively classify this new specimen as cf. Susisuchus sp., and provide new anatomical information for this rather derived crocodylomorph.
A new species of Notosuchia, Labidiosuchus amicum gen. et sp. nov., is described based on an incomplete lower jaw (DGM 1480‐R) from the Upper Cretaceous Marília Formation (Maastrichtian) recovered from a quarry near the Peirópolis municipality, Minas Gerais State, Southeastern Brazil. The mandibular symphysis is long, strong anterodorsally projected and ‘Y‐shaped’. The bizarre dentition is formed by at least eight teeth placed in a symphyseal tooth battery, some located lateral to each other. The first pair is larger than all others and procumbent. Some teeth are obliquely implanted (anterolabially to posterolingually) and have sub circular to elliptical outline. At least the posterior teeth are single cuspidate with acute apex. Labidiosuchus amicum shows a rather bizarre dentition, increasing the taxonomic diversity and potential feeding strategies of notosuchian crocodylomorphs. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163, S109–S115.
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