[dinosaur] Large sphagesaurid notosuchian from Upper Cretaceous of Brazil + crocodylomorph cranial shape

Ben Creisler
[email protected]


Some recent papers:

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Galuber Oliveira Cunha, Rodrigo Santucci, Marco Brandalise Andrade & Carlos
Eduardo Maia Oliveira (2019)
Description and phylogenetic relationships of a large-bodied sphagesaurid
notosuchian from the Upper Cretaceous Adamantina Formation, Bauru Group,
São Paulo, southeastern Brazil.
Cretaceous Research (advance online publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1016_j.cretres.2019.104259&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=oTd2Ob_A3aT53cfy3x_q5bSTJwtT_q9FS8blHK0fR1o&s=3tzCuZhDSx3JBYLjrGjyj2Mnf1SRkKQGM6GaoIkrK5w&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.sciencedirect.com_science_article_pii_S0195667119300667&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=oTd2Ob_A3aT53cfy3x_q5bSTJwtT_q9FS8blHK0fR1o&s=ihVRknnD3WNXQZAmItOMx_Wsqq_IEwDwgpHwZcZl7g8&e= 


In this work we describe new remains and possible gastroliths of a
sphagesaurid (Mesoeucrocodylia: Notosuchia) unearthed from the Adamantina
Formation (Bauru Group, Upper Cretaceous) in the municipality of
Fernandópolis-SP, which add new data about the dental, dermal shield, and
the post-cranial skeleton morphology of these crocodilians. Phylogenetic
analyses place the studied fossil within Sphagesauridae, in a polytomy with
Armadillosuchus arrudai and Caryonosuchus pricei. The anatomical
comparisons are congruent to the phylogenetic analysis since they also
suggest that the specimen herein described is closely related to other
larger-bodied Sphagesauridae species, such as Armadillosuchus arrudai. The
new skull, appendicular, and dermal elements described in this work may
provide data for the elaboration of new phylogenetic characters which can
improve cladistic analyses concerning Sphagesauridae species, as well as
they may help to better understand the morphological complexity of this
family of crocodylomorphs, especially the large-bodied species.

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Now officially published under peer review:


Pedro L. Godoy (2019)
Crocodylomorph cranial shape evolution and its relationship with body size
and ecology.
Journal of Evolutionary Biology (advance online publication)
doi: https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1111_jeb.13540&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=oTd2Ob_A3aT53cfy3x_q5bSTJwtT_q9FS8blHK0fR1o&s=nIXWoG9iWP41TSXXNu9_OvgXX9k1MinB6iljtrUyWnA&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__onlinelibrary.wiley.com_doi_10.1111_jeb.13540&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=oTd2Ob_A3aT53cfy3x_q5bSTJwtT_q9FS8blHK0fR1o&s=pe4rxbLoeTpYpKO500erxR4sYItZ0jQhs-tWsw5aWro&e= 


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.

****

Free preprint version (posted earlier):

Pedro Lorena Godoy (2019)
Crocodylomorph cranial shape evolution and its relationship with body size
and ecology.
BioRxiv (preprint)
doi: https://urldefense.proofpoint.com/v2/url?u=http-3A__dx.doi.org_10.1101_724609&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=oTd2Ob_A3aT53cfy3x_q5bSTJwtT_q9FS8blHK0fR1o&s=chvmzxtcVV_kNeBj9gtR4JADwo7DNVbPpNaqCscON0s&e= 
https://urldefense.proofpoint.com/v2/url?u=https-3A__www.biorxiv.org_content_10.1101_724609v1&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=oTd2Ob_A3aT53cfy3x_q5bSTJwtT_q9FS8blHK0fR1o&s=qV5OTQ44vfP8DCAn_zpmjT7bPOmzhrEc_RkeD4enDSs&e= 

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