A New 13 Million Year Old Gavialoid Crocodylian from Proto-Amazonian Mega-Wetlands Reveals Parallel Evolutionary Trends in Skull Shape Linked to Longirostry

Salas-Gismondi, Rodolfo; Flynn, John J.; Baby, Patrice; Tejada-Lara, Julia V.; Julien, Claude; Antoine, Pierre

doi:10.1371/journal.pone.0152453

Cited by 52 publications

(51 citation statements)

References 46 publications

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“…The Moroccan gavialoids are the westernmost known gavialoids from the Eocene. These discoveries could be of particular importance, because the earliest known South American gavialoids are from the latest Eocene (Salas-Gismondi et al, 2016). The Eocene and the Oligocene are particularly important in the dispersal of gavialoids because the split between South American and Asian clades of gavialoids could date from the late Eocene-Oligocene (Salas-Gismondi et al, 2016).…”

Section: Paleobiogeographic Implicationsmentioning

confidence: 99%

“…These discoveries could be of particular importance, because the earliest known South American gavialoids are from the latest Eocene (Salas-Gismondi et al, 2016). The Eocene and the Oligocene are particularly important in the dispersal of gavialoids because the split between South American and Asian clades of gavialoids could date from the late Eocene-Oligocene (Salas-Gismondi et al, 2016). Moreover, phylogenetic relationships suggest strong connections between basal South American gavialoids, Eogavialis africanum, and the Moroccan Argochampsa krebsi Hua andJouve, 2004.…”

Section: Paleobiogeographic Implicationsmentioning

confidence: 99%

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Longirostrine crocodylians from the Bartonian of Morocco and Paleogene climatic and sea level oscillations in the Peri-Tethys area

Jouve¹,

Khalloufi

Zouhri

2019

Journal of Vertebrate Paleontology

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The Eocene-Oligocene transition was a period of high faunal and floral turnover, often correlated with climatic deterioration. Crocodyliforms are climate sensitive, and they have been often used for reconstruction of paleoclimates. The description of crocodylian material from the Bartonian of Aaiun-Tarfaya Basin (Morocco) allows the recognition of at least two longirostrine crocodylians, including a gavialoid. This identification is important, because the migration of gavialoids to South America probably occurred during the late Eocene. Close relationships between late Eocene-early Oligocene Eogavialis africanum from Egypt, Argochampsa krebsi from the Paleocene of Morocco, and the South American gavialoid clade suggests that Morocco could have had a particular place in the gavialoid dispersal route to South America. The resemblance between Moroccan material described herein and E. africanum is thus important in this context. Analysis of the distribution of longirostrine crocodylians in the Peri-Tethys area through the Eocene-Oligocene shows a strong difference in the evolution of the distribution between longirostrine crocodylians and Diplocynodon. Whereas the freshwater Diplocynodon has a continuous distribution in western Europe, the mainly marine longirostrine crocodylians have a northern maximal expansion that moves southward during the middle Eocene, being restricted to North Africa during late Eocene-early Oligocene. European freshwater Asiatosuchus-like taxa also disappear during the late Eocene. Climatic deterioration, helped by sea level oscillations, may have strongly impacted the diversity and latitudinal distribution of the crocodylians, but we highlight a possible differential tolerance in range of climatic conditions between crocodylians. This could help to refine the use of crocodylians as paleoclimatic proxies.

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Section: Paleobiogeographic Implicationsmentioning

confidence: 99%

Section: Paleobiogeographic Implicationsmentioning

confidence: 99%

Longirostrine crocodylians from the Bartonian of Morocco and Paleogene climatic and sea level oscillations in the Peri-Tethys area

Jouve¹,

Khalloufi

Zouhri

2019

Journal of Vertebrate Paleontology

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“…Previous works that use geometric morphometrics for studying crocodylomorph cranial shape have mostly focused on specific subgroups, especially crocodylians (Monteiro et al ., 1997; Pierce et al ., 2008; Sadleir & Makovicky, 2008; Piras et al ., 2009, 2010, 2014; Pearcy & Wijtten, 2011; Watanabe & Slice, 2014; Okamoto et al ., 2015; Clarac et al ., 2016; Salas-Gismondi et al ., 2016, 2018; Iijima, 2017; McCurry et al ., 2017 a ; Foth et al ., 2017; Bona et al ., 2018; Fernandez Blanco et al ., 2018; Morris et al ., 2019), but also thalattosuchians (Pierce et al ., 2009; Young et al ., 2010) and notosuchians (Godoy et al ., 2018). One important exception is the recent work of Wilberg (2017), that assessed cranial shape variation across Crocodyliformes (which is only slightly less inclusive than Crocodylomorpha; Irmis et al ., 2013), sampling a large number of species.…”

Section: Introductionmentioning

confidence: 99%

Crocodylomorph cranial shape evolution and its relationship with body size and ecology

Godoy

2019

Preprint

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Crocodylomorpha, which includes living crocodylians and their extinct relatives, has a rich fossil record, extending back for more than 200 million years. Unlike modern semi-aquatic crocodylians, extinct crocodylomorphs exhibited more varied lifestyles, ranging from marine to fully terrestrial forms. This ecological diversity was mirrored by a remarkable morphological disparity, particularly in terms of cranial morphology, which seems to be closely associated with ecological roles in the group. Here, I use geometric morphometrics to comprehensively investigate cranial shape variation and disparity in Crocodylomorpha. I quantitatively assess the relationship between cranial shape and ecology (i.e. terrestrial, aquatic, and semi-aquatic lifestyles), as well as possible allometric shape changes. I also characterise patterns of cranial shape evolution and identify regime shifts. I found a strong link between shape and size, and a significant influence of ecology on the observed shape variation. Terrestrial taxa, particularly notosuchians, have significantly higher disparity, and shifts to more longirostrine regimes are associated with large-bodied aquatic or semi-aquatic species. This demonstrates an intricate relationship between cranial shape, body size and lifestyle in crocodylomorph evolutionary history. Additionally, disparity-through-time analyses were highly sensitive to different phylogenetic hypotheses, suggesting the description of overall patterns among distinct trees. For crocodylomorphs, most results agree in an early peak during the Early Jurassic and another in the middle of the Cretaceous, followed by nearly continuous decline until today. Since only crown-group members survived through the Cenozoic, this decrease in disparity was likely the result of habitat loss, which narrowed down the range of crocodylomorph lifestyles.

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“…The shape of the skull, and particularly the rostrum, has long been considered both an important phylogenetic and ecomorphological feature in crocodylians (Busbey, 1995;Daniel & McHenry, 2001;Brochu, 2001;Sadleir & Makovicky, 2008;Salas-Gismondi et al, 2016;Drumheller, Wilberg, & Sadlier, 2016;Wilberg, 2017). We attempted to determine if there was a correlation between tooth morphology and head shape, as these traits may be linked.…”

Section: Skull Data Collectionmentioning

confidence: 99%

Peer Review #3 of "Quantitative heterodonty in Crocodylia: assessing size and shape across modern and extinct taxa (v0.2)"

Cossette¹

2019

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Heterodonty in Crocodylia and closely related taxa has not been defined quantitatively, as the teeth rarely have been measured. This has resulted in a range of qualitative descriptors, with little consensus on the condition of dental morphology in the clade. The purpose of this study is to present a method for the quantification of both size-and shapeheterodonty in members of Crocodylia. Data were collected from dry skeletal and fossil specimens of 34 crown crocodylians and one crocodyliform, resulting in 21 species total. Digital photographs were taken of each tooth and the skull, and the margins of both were converted into landmarks and semilandmarks. We expressed heterodonty through Foote's morphological disparity, and a principal components analysis quantified shape variance. All specimens sampled were heterodont to varying degrees, with the majority of the shape variance represented by a 'caniniform' to 'molariform' transition. Heterodonty varied significantly between positions; size undulated whereas shape was significantly linear from mesial to distal. Size and shape appeared to be primarily decoupled. Skull shape correlated significantly with tooth shape. High size-heterodonty often correlated with very large caniniform teeth, reflecting a prioritization of securing prey. Large, highly molariform, distal teeth may be a consequence of high-frequency durophagy combined with prey size. The slender-snouted skull shape correlated with a caniniform arcade with low heterodonty. This was reminiscent of other underwater-feeding tetrapods, as they often focus on small prey that requires minimal processing. Several extinct taxa were very molariform, which was associated with low heterodonty. The terrestrial peirosaurid shared similarities with large modern crocodylian taxa, but may have processed prey differently. Disparity measures can be inflated or deflated if certain teeth are absent from the tooth row, and regression analysis may not best apply to strongly slender-snouted taxa. Nevertheless, when these methods are used in tandem they can give a complete picture of crocodylian heterodonty. Future researchers may apply our proposed method to most crocodylian

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A New 13 Million Year Old Gavialoid Crocodylian from Proto-Amazonian Mega-Wetlands Reveals Parallel Evolutionary Trends in Skull Shape Linked to Longirostry

Cited by 52 publications

References 46 publications

Longirostrine crocodylians from the Bartonian of Morocco and Paleogene climatic and sea level oscillations in the Peri-Tethys area

Longirostrine crocodylians from the Bartonian of Morocco and Paleogene climatic and sea level oscillations in the Peri-Tethys area

Crocodylomorph cranial shape evolution and its relationship with body size and ecology

Peer Review #3 of "Quantitative heterodonty in Crocodylia: assessing size and shape across modern and extinct taxa (v0.2)"

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