首页|Paleobiological inferences on middle Eocene native ungulates from South America: Functional morphological analysis of Notostylops and Notopithecus

Paleobiological inferences on middle Eocene native ungulates from South America: Functional morphological analysis of Notostylops and Notopithecus

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Eocene early-diverging representatives of South American extinct notungulates are traditionally considered to have been "generalists" and "non-specialized" in terms of the appendicular skeleton and locomotor behavior, as is the case with the notostylopid Notostylops, a middle Eocene iconic taxon from Patagonia (Argentina). However, they are mainly known from dental remains, and associated cranial and postcranial elements are scarce. The discovery of a nearly complete specimen attributed to N. murinus allows us to: (1) increase the knowledge of the anatomy of its appendicular skeleton; (2) identify isolated bones from several collections and suggest different taxonomic interpretations for published specimens; (3) perform a biomechanical and functional study using functional morphological analysis to infer its paleoecological attributes (e.g. posture, locomotor habit, estimated speed, and body mass); and (4) establish morphofunctional comparisons, based on possible functional ranges, with other extinct early-diverging notoungulates from the middle Eocene, such as the Notopithecid Notopithecus. Our evidence suggests that Notostylops was a medium-sized mammal (8.5-20 kg), which could achieve a dynamic digitigrade posture that allowed a scansorial secondary locomotor habit and a speed of up to 50 km/h. However, Notopithecus was a small-sized mammal (0.6-1.4 kg) with a plantigrade posture both in a static and dynamic context, terrestrial habits, and a speed of up to 35 km/h. Therefore, we conclude that these Eocene notoungulates show different locomotor capabilities, which can be associated with early niche diversifications, clearly contrasting with the "all-generalists" paradigmatic view.

appendicular skeletonbiomechanicsearly-diverging SANUpaleobiological attributesPaleogene1897 NOTOUNGULATAAMEGHINO

Vera, Barbara、Medina-Gonzalez, Paul、Moreno, Karen

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Universidad Catolica del Maule,Univ Catolica Maule

Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET),UNPSJB

Inst Ciencias Tierra,Univ Austral Chile

2022

Journal of Morphology

Journal of Morphology

SCI
ISSN:0362-2525
年,卷(期):2022.283(9)
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