Baurusuchus

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Baurusuchus
Temporal range: Late Cretaceous, Turonian–Santonian
Skull of Baurusuchus salgadoensis
Skeletal reconstruction
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauria
Clade: Pseudosuchia
Clade: Crocodylomorpha
Clade: †Notosuchia
Clade: †Sebecosuchia
Family: †Baurusuchidae
Subfamily: †Baurusuchinae
Genus: †Baurusuchus
Price, 1945
Type species
†Baurusuchus pachecoi
Price, 1945
Other species
  • †B. albertoi?
    Nascimento & Zaher, 2010
  • †B. salgadoensis
    Carvalho et al., 2005
Skeletal diagram and size comparison showing some of the different Baurusuchus specimens in scientific literature (human: 175 cm tall). Several more specimens have been discovered and stored in museums

Baurusuchus is an extinct genus of baurusuchid mesoeucrocodylian, which lived in Brazil from 90 to 83.5 million years ago, in the Late Cretaceous period. It was a terrestrial predator, estimated to reach up to 113.4 kilograms (250 lb) in weight.[1] Baurusuchus lived during the Turonian to Santonian stages of the Late Cretaceous Period, in Adamantina Formation, Brazil.[2] It gets its name from the Brazilian Bauru Group ("Bauru crocodile"). It was related to the earlier-named Cynodontosuchus rothi, which was smaller, with weaker dentition.[3] The three species are B. pachecoi, named after Eng Joviano Pacheco, its discoverer,[4] B. salgadoensis (named after General Salgado County in São Paulo, Brazil)[5] and B. albertoi (named after Alberto Barbosa de Carvalho, Brazilian paleontologist).[2] The latter species is disputed (see phylogeny section). Its relatives include the similarly sized Stratiotosuchus from the Adamantina Formation, and Pabweshi, from the Pakistani Pab Formation.

Paleoecology

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Life restoration of B. salgadoensis

B. salgadoensis is seen as a terrestrial predator, living in a hot and arid climate. The position of the external nares was unsuited for an amphibious lifestyle like in modern crocodilians and the snout and teeth are laterally compressed like in theropods. Both of this supports the terrestrial hypothesis. The hot environment hypothesis is based on the lifestyle of modern crocodilians and the stratigraphy of Baurusuchus. B. salgadoensis was found in fine massive sandstones which are interpreted as a floodplain area in a hot and arid climate. Baurusuchus was likely able to dig holes for finding water in dry seasons or, like modern alligators do, for thermoregulation. The occurrence of several complete skeletons and skulls of different ontogenetic stages in correlated stratigraphic levels supports this. Such a strategy would have made it less water-bound than most modern crocodiles, allowing it to live in more continental climate. The strongly bent pterygoids suggest powerful muscles that could close its jaw very quickly, but relatively weakly. The skull and tooth morphology indicates that the biting strategies of Baurusuchus were similar to a Komodo dragon which include ambushing the prey, biting it and pulling back the serrated, blade-like teeth. Perhaps violently shaking prey with its jaws like modern crocodiles, helped by its enlarged cervical neural spines, which served as large muscle attachments[6]. Baurusuchus likely played an important role in its ecosystem, competing with the abelisaurids for food.[5]

Classification

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B. albertoi

Baurusuchus is the type genus of the family Baurusuchidae, a family consisting of crocodilians with elongated and laterally compressed skulls.[4] Other members of that family from the Cretaceous of South America include Stratiotosuchus and Cynodontosuchus, but baurusuchids are also known from the Cretaceous of Asia (Pakistan) and the Tertiary of Europe.[5]

A study in 2011 erected a new subfamily called Baurusuchinae. Seven diagnostic features for the group were described which include the moderate size and the broad frontals. The paper referred only Stratiotosuchus maxhechti and Baurusuchus to the subfamily, making Stratiotosuchus Baurusuchus' closest relative so far.[7] However, a study in the year 2014 referred a new species called Aplestosuchus sordidus to the subfamily, but supported a closer relationship of Baurususchus with Stratiotosuchus than with it. The species B. albertoi is an exception. The paper does not support its affiliation to Baurusuchus and views it as a close relative of Aplestosuchus. This is the cladogram they presented:[8]

Sources

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References

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  1. ^ Dumont Jr, Marcos V.; Santucci, Rodrigo M.; de Andrade, Marco Brandalise; de Oliveira, Carlos Eduardo Maia (2022). "Paleoneurology of Baurusuchus (Crocodyliformes: Baurusuchidae), ontogenetic variation, brain size, and sensorial implications". The Anatomical Record. 305 (10): 2670–2694. doi:10.1002/ar.24567. hdl:10923/19660. ISSN 1932-8486. PMID 33211405.
  2. ^ a b Paulo Miranda Nascimento & Hussam Zaher (2010). "A new species of Baurusuchus (Crocodyliformes, Mesoeucrocodylia) from the Upper Cretaceous of Brazil, with the first complete postcranial skeleton described from the family Baurusuchidae" (PDF). Papéis Avulsos de Zoologia. 50 (21): 323‑361. doi:10.1590/s0031-10492010002100001.
  3. ^ Bonaparte, Jose F. (1996). "Cretaceous tetrapods of Argentina". Muncher Geowissenschaften, Abhandlungen. 30: 73–130.
  4. ^ a b Price, L.I. (1945). "A new reptile from the Cretaceous of Brazil". Departamento Nacional da Produção Mineral, Notas Preliminares e Estudos. 25. Rio de Janeiro: 1–8.
  5. ^ a b c Carvalho; Campos, Antonio; de Celso, Arruda; Nobre, Pedro Henrique (2005). "Baurusuchus salgadoensis, a new Crocodylomorpha from the Bauru Basin (Cretaceous), Brazil" (PDF). Gondwana Research. 8 (1): 11–30. Bibcode:2005GondR...8...11C. doi:10.1016/S1342-937X(05)70259-8. ISSN 1342-937X.
  6. ^ Montefeltro, Felipe C.; Lautenschlager, Stephan; Godoy, Pedro L.; Ferreira, Gabriel S.; Butler, Richard J. (2020). "A unique predator in a unique ecosystem: modelling the apex predator within a Late Cretaceous crocodyliform-dominated fauna from Brazil". Journal of Anatomy. 237 (2): 323–333. doi:10.1111/joa.13192. ISSN 1469-7580. PMC 7369189. PMID 32255518.
  7. ^ Felipe C. Montefeltro; Hans C. E. Larsson; Max C. Lange (2011). "A new baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the Late Cretaceous of Brazil and the phylogeny of Baurusuchidae". PLOS ONE. 6 (7): e21916. Bibcode:2011PLoSO...621916M. doi:10.1371/journal.pone.0021916. PMC 3135595. PMID 21765925.{{cite journal}}: CS1 maint: article number as page number (link)
  8. ^ Godoy PL, Montefeltro FC, Norell MA, Langer MC (2014). "An additional baurusuchid from the Cretaceous of Brazil with evidence of interspecific predation among Crocodyliformes". PLOS ONE. 9 (5): e97138. Bibcode:2014PLoSO...997138G. doi:10.1371/journal.pone.0097138. PMC 4014547. PMID 24809508.{{cite journal}}: CS1 maint: article number as page number (link)