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. 2026 Jun;309(6):1451-1463.
doi: 10.1002/ar.70021. Epub 2025 Jul 18.

Histovariability and fossil diagenesis of Pissarrachampsa (Pseudosuchia, Notosuchia, Baurusuchidae) from the Upper Cretaceous of Southeast Brazil

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Histovariability and fossil diagenesis of Pissarrachampsa (Pseudosuchia, Notosuchia, Baurusuchidae) from the Upper Cretaceous of Southeast Brazil

Tito Aureliano et al. Anat Rec (Hoboken). 2026 Jun.

Abstract

Notosuchians were key components of western Gondwanan Cretaceous ecosystems in terrestrial predator niches and exhibited remarkable taxonomic and ecological diversity. Previous research has explored their physiology, metabolism, and histology, revealing varied growth patterns and life history strategies. While significant advancements have been made in recent years, there is much to unveil about the evolution of growth rate strategies within this clade. Here, we analyzed the histological variability of Pissarrachampsa sera, a baurusuchid from the Upper Cretaceous Adamantina Formation in Southeast Brazil, to investigate its growth dynamics and ecological adaptations. Thin sections from the femur, tibia, and fibula revealed fibrolamellar bone tissue with varied vascularization patterns, including radial, reticular, plexiform, laminar, and longitudinal canals. These patterns indicate differential growth rates among skeletal elements, with the tibia growing the fastest and the fibula the slowest. External Fundamental System and multiple Lines of Arrested Growth suggest somatic maturity in this young adult specimen. Limited diagenetic artifacts ensured reliable preservation for paleohistological interpretation. This study provides valuable information about notosuchian physiology and their evolutionary success in Gondwanan terrestrial ecosystems during the Mesozoic. Future investigations should aim to expand histological sampling across diverse taxa to refine our understanding of notosuchian growth strategies and ecological roles.

Keywords: Archosauria; Pseudosuchia; anatomy; paleontology; petrography.

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Figures

FIGURE 1
FIGURE 1
Pissarrachampsa LPITB‐PV 57, photographs (a, c, e, g, i, k) and 3D models created from computed tomography (CT) scan (b, d, f, h, j, l). (1) Left femur in anterior (a, b), medial (c, d), posterior (e, f), lateral (g, h), proximal (i, j) and distal (k, l) views. (h1–h3), Cross‐sections of the CT scan (shown in 1h). (2) Right tibia in anterior (a, b), medial (c, d), posterior (e, f), lateral (g, h), proximal (i, j), and distal (k, l) views. (f1–f3) Cross‐sections of the CT scan (shown in 2f). (3) Right fibula in anterior (a, b), lateral (c, d), posterior (e, f), medial (g, h), proximal (i, j), and distal (k, l) views. (b1–b3) Cross‐sections of the CT scan (shown in 3b). cf, corpus femoris; cl, condylus lateralis; clf, Musculus caudofemoralis longus; cm, condylus medialis; cof, corpus fibulae; ei, eminentia intercondylaris; ft, fourth trochanter; mi, muscular insertion; mic, M. ischiotrochantericus; nf, nutrient foramen; pifi, M. puboischiofemoralis internus; tmj, trochanter major; tsm, tuberositas supracondylaris medialis; tt, tuberositas tibiae. Scale in (a–h) = 50 mm; (i and j) = 20 mm, (k and l) = 10 mm. h1–h3, f1–f3, b1–b3 = not to scale.
FIGURE 2
FIGURE 2
Femur histology of the baurusuchid notosuchian Pissarrachampsa LPITB‐PV 57 from the Upper Cretaceous of Southeast Brazil. (a) Midshaft cross‐section showing the index of areas detailed in (b–h). (b) histologic profile. DIA, diagenetic artifact; EFS, External Fundamental System; IFS, Internal Fundamental System; LAG, Line of Arrested Growth; MLAGS, multiple LAGs; PO, primary osteon; PX, plexiform canal; RC, resorption cavity; RE, reticular canal; SF, Sharpey's fibers. Normal light in (a). Polarized under parallel nicols in (c, g). Crossed nicols with lambda compensator in (h). Scale bar in A = 5 mm; (b, e, g) = 200 μm; (c, d, f, h) = 100 μm.
FIGURE 3
FIGURE 3
Tibia histology of the baurusuchid notosuchian Pissarrachampsa LPITB‐PV 57 from the Upper Cretaceous of Southeast Brazil. (a) Midshaft cross‐section showing the index of areas detailed in (b–h). (b) Histologic profile. DIA, diagenetic artifacts; EFS, External Fundamental System; IFS, Internal Fundamental System; LAG, Line of Arrested Growth; MLAGS, multiple LAGs; PO, primary osteon; RAD, radial canal; RC, resorption cavity; RE, reticular canal. Normal light in (a). Polarized under parallel nicols in (b–e, g). Crossed nicols with lambda compensator in (f, h). Scale bar in (a) = 5 mm; (b, f, g) = 200 μm; (c–e, h) = 100 μm.
FIGURE 4
FIGURE 4
Fibula histology of the baurusuchid notosuchian Pissarrachampsa LPITB‐PV 57 from the Upper Cretaceous of Southeast Brazil. (a) Midshaft cross‐section showing the index of areas detailed in (b–h). (b) Histologic profile. DIA, diagenetic artifacts; EFS, External Fundamental System; IFS, Internal Fundamental System; LAG, Line of Arrested Growth; MB, Medullary Bone; MLAGS, multiple LAGs; PO, primary osteon; PX, plexiform canal; RC, resorption cavity; SF, Sharpey's fibers. Normal light in (a). Polarized under parallel nicols in (c, g). Crossed nicols with lambda compensator in (h). Scale bar in (a) = 5 mm; (b) = 200 μm; (c, e–h) = 100 μm; (d) = 50 μm.

References

    1. Andrade, R. C. L. P. , Sena, M. V. A. , Brum, A. S. , Campos, D. A. , Kellner, A. W. A. , Bantim, R. A. M. B. , & Sayão, J. M. (2023). Osteohistology of the large‐sized cretaceous crocodylomorph Stratiotosuchus maxhechti (Notosuchia, Baurusuchidae) indicates fast growth and niche partitioning with medium‐sized theropods. Journal of South American Earth Sciences, 127, 104363.
    1. Arai, M. , & Dias‐Brito, D. (2023). Supersequência Bauru (Cretáceo da Bacia do Paraná): Revisão estratigráfica com base em dados paleontológicos recentes. Derbyana, 44, 1–31. 10.14295/derb.v44.800 - DOI
    1. Aureliano, T. , Ghilardi, A. M. , Buck, P. V. , Fabbri, M. , Samathi, A. , Delcourt, R. , Fernandes, M. A. , & Sander, M. (2018). Semi‐aquatic adaptations in a spinosaur from the Lower Cretaceous of Brazil. Cretaceous Research, 90, 283–295.
    1. Aureliano, T. , Ghilardi, A. M. , Fernandes, M. A. , & Ricardi‐Branco, F. S. (2023). Air sac attachments or tendon scars: The distinction between soft tissue traces in archosaur bone. Zoological Journal of the Linnean Society, 202, zlac103.
    1. Aureliano, T. , Ghilardi, A. M. , Fonseca, P. H. M. , Martinelli, A. G. , & Marinho, T. S. (2023). The evolution and diversification of growth strategies in abelisauroid theropods. Journal of Vertebrate Paleontology, 43, e2298395. 10.1080/02724634.2023.2298395 - DOI

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