Patagonian Eocene Archaeopithecidae Ameghino, 1897 (Notoungulata): systematic revision, phylogeny and biostratigraphy

Vera, Bárbara

doi:10.1017/jpa.2017.53

Cited by 15 publications

(17 citation statements)

References 38 publications

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“…The peculiar eruption sequence (d)P/p4→(d)P/p3→(d)P/p2) described here for the Interatheriinae was observed in the Eocene henricosborniid Henricosbornia (Vera, 2016) and other Typotheria, such as the Eocene Archaeopithecidae Archaeopithecus (Vera, 2017), the Notopithecinae (Vera, 2013; Vera and Cerdeño, 2014), except for Guilielmoscottia plicifera Ameghino, 1901 (sequence P/p3→P/p4→P/p2), and the hegetotheriids Paedotherium (Cerdeño et al, 2017), Hegetotherium mirabile , and Pachyrukhos moyani (M.F., personal observation). The simultaneous presence of dP2 and P3–4 described for the leontinid Coquenia bondi (Deraco and García López, 2011) and of the barely worn P/p2 along with more-worn P/p3–4 observed in the notohippid Notohippus toxodontoides (personal observation) allows us to infer the same delay in the eruption of P2 as the interatheriines studied here, but P/p4 and P/p3 erupt almost simoultanesly.…”

Section: Discussionmentioning

confidence: 50%

Deciduous dentition and dental eruption sequence in Interatheriinae (Notoungulata, Interatheriidae): implications in the systematics of the group

2021

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Studies focused on deciduous dentition, ontogenetic series, and tooth eruption and replacement patterns in fossil mammals have lately increased due to the recognized taxonomic and phylogenetic weight of these aspects. A study of the deciduous and permanent dentition of Interatherium and Protypotherium (Interatheriinae) is presented, based mainly on unpublished materials. Deciduous cheek teeth are brachydont and placed covering the apex of the respective permanent tooth; in addition, some morphological and metrical differences are observed along the crown height. Five dental ontogenetic stages are distinguished among the juvenile specimens on the basis of the degree of wear, the replacement of the deciduous premolars, and the eruption of the molars. The crown height and the wear degree of different Interatheriinae taxa show: (1) eruption pattern of molars in an anterior–posterior direction (M/m1 to M/m3); (2) pattern of replacement of deciduous premolars and eruption of permanent premolars in a posterior–anterior direction (dP/dp4 to dP/dp2 and P/p4 to P/p2); and (3) eruption of M/m3 before the replacement of dP/dp4. Results allow evaluating the diagnostic dental characteristics used to describe some interatheriines, as well as reinterpreting some taxonomic assumptions: the holotype of Protypotherium diversidens Ameghino, 1891 is recognized as a juvenile of another species of the genus, and the species is not validated, considering it as Protypotherium sp.; the holotype of Eudiastatus lingulatus Ameghino, 1891 falls in the variability of Protypotherium, becoming P. lingulatus new combination, tentatively maintaining the species and implying the synonymy between Eudiastatus and Protypotherium; and the holotype of Eopachyrucos ranchoverdensis Reguero, Ubilla, and Perea, 2003 is reinterpreted as bearing deciduous premolars.

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Section: Discussionmentioning

confidence: 50%

Deciduous dentition and dental eruption sequence in Interatheriinae (Notoungulata, Interatheriidae): implications in the systematics of the group

2021

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“…For extinct mammals, we used predictive equations (Supporting Information: appendix ) according to osteological variables, such as astragalus (Tsubamoto, 2014; n = 80), calcaneus (Tsubamoto, 2019; n = 69), and dental measurements (Janis, 1990; n = 136; Scarano et al, 2011; n = 35). Data sets of dental measurements (length of first lower molar, second upper molar, lower molar raw, third lower molar) were taken from different authors (Simpson, 1948; Vera, 2017; Vera & Krause, 2020). Body mass estimation from the circumference of the humerus and femur follows Campione and Evans (2012).…”

Section: Methodsmentioning

confidence: 99%

“…Using data taken from long bones (humerus and femur), tarsus (astragalus and calcaneus), and teeth (Simpson, 1948;Vera, 2012Vera, , 2017Vera & Krause, 2020; this work; Table 2), we estimated the range of body masses for N. murinus and N. adapinus applying different models (Campione & Evans, 2012;Janis, 1990;Scarano et al, 2011;Tsubamoto, 2014Tsubamoto, , 2019. The body mass range for N. murinus (MPEF-PV 1115) was estimated between 8.5 and 20 kg (Figure 11c), which indicates a medium-sized mammal.…”

Section: Body Massmentioning

confidence: 99%

“…Body mass (mean and minimum to maximum values in kg) has range between 0.6−1.4 kg, which corresponds to a small-sized mammal. Abbreviations in Figure2.T A B L E 2 Body masses (mean values, bold numbers in kg) for Notostylops and Notopithecus based on dental measurements (data set taken fromSimpson 1948;Vera, 2017;Vera & Krause, 2020; and personal data by BV).…”

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confidence: 99%

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

Vera

Medina-González

Moreno

2022

Journal of Morphology

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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 earlydiverging 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.

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“…Traditionally, shape and age variation in the dentition of extinct native South America ungulates (Notoungulata) has been described in terms of both qualitative (morphological) and quantitative (linear dimensions or other measurements) changes, taking a controversial role in the systematics of several groups (e.g., Billet, De Muizon, & Quispe, ; Billet et al, ; Cerdeño, Montalvo, & Sostillo, ; Cerdeño, Reguero, & Vera, ; Cerdeño et al, ; Croft, Reguero, Bond, Wyss, & Flynn, ; Francis, ; Madden, ; Vera, ). For instance, using geometric morphometrics to analyze high‐crowned upper and lower teeth, Ercoli, Candela, Rasia, and Ramírez () revalidated a species of Paedotherium (Hegetotheriidae) from the Late Miocene; however, no previous GM analysis has been done on the low‐crowned dentition of Eocene notoungulates.…”

Section: Introductionmentioning

confidence: 99%

Geometric morphometric analysis as a proxy to evaluate age‐related change in molar shape variation of low‐crowned Notoungulata (Mammalia)

Scarano

Vera

2017

Journal of Morphology

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Shape and age variation in dentition of Paleogene extinct native South American ungulates (Notoungulata) has been traditionally described using qualitative and quantitative approaches, and has played a controversial role in the systematics of several groups. Such is the case of the Notopithecidae, a group of notoungulates with low-crowned teeth, known from the middle Eocene of Patagonia (Argentina). In this group, as well as in other contemporary families, extreme morphological changes associated to increasing dental wear were originally assumed to represent taxonomic differences; thus, dozens of species were erected, clearly reflecting the difficulty of defining discrete characters. In this contribution, a total of 89 upper molars and 91 lower molars were analyzed distributed in two factors, wear and species; three species of notopithecids were considered as study case, Notopithecus adapinus, Antepithecus brachystephanus, and Transpithecus obtentus, based on the large and well-identified sample of upper and lower molars for each species. We have coupled geometric morphometric analyses with traditional comparative methods to get a better understanding and interpretation of both the changes in tooth shape contour and the link between shape and ontogeny. In addition, we evaluate the utility of this approach to identify which changes are strictly wear-related and also test the qualitative characteristics used for diagnosing and differentiating notopithecid species. Our study yielded consistent results when applying independent geometric morphometric analyses on complex structures such as brachydont molar teeth. The landmark data is highly congruent with alternative sources of evidence, such as morphological studies using discrete characters. In notopithecid species, wear is the main factor affecting molar shape, followed by species (in lower molars) and allometry; in addition, lower teeth morphology is more definitive in separating species than upper molars, a fact that entails a key point for systematic studies of Paleogene brachydont notoungulates.

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Patagonian Eocene Archaeopithecidae Ameghino, 1897 (Notoungulata): systematic revision, phylogeny and biostratigraphy

Cited by 15 publications

References 38 publications

Deciduous dentition and dental eruption sequence in Interatheriinae (Notoungulata, Interatheriidae): implications in the systematics of the group

Deciduous dentition and dental eruption sequence in Interatheriinae (Notoungulata, Interatheriidae): implications in the systematics of the group

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

Geometric morphometric analysis as a proxy to evaluate age‐related change in molar shape variation of low‐crowned Notoungulata (Mammalia)

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