A Late Miocene Argyrolagidae (Mammalia, Metatheria, Bonapartheriiformes) from Northwestern Argentina

García-López, Daniel A.; Babot, María Judith

doi:10.5710/amgh.17.02.2015.2876

Cited by 11 publications

(16 citation statements)

References 13 publications

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“…Other specimen referred to Microtragulus sp. (PVL 6594;García-López and Babot, 2015), shows similar structures. Given this arrangement, we infer that a proper infraorbital canal is absent, being replaced by a sulcus (corresponding to the medial wall of the canal) connected anteriorly to a foramen piercing the maxilla anterior to the orbit.…”

Section: Descriptionmentioning

confidence: 48%

“…The arrangement of molar cusps in Microtragulus bolivianus (Figure 2) is based on this hypothesis and in García-López and Babot (2015). Cusp names are used as if they were actually present, although according to the condition of typical euhypsont teeth, the cusped surface is quickly worn away after tooth eruption (sidewall hypsodonty sensu Koenigswald, 2011).…”

Section: Methodsmentioning

confidence: 99%

“…The current geographical record indicates a disjunct distributional pattern comprising coastal as well as highland areas. Microtragulus reigi is the only species known from lowland areas (the existence of M. argentinus remains questionable; see Discussion) and M. catamarcensis and M. bolivianus are restricted to mid and high altitudes (García-López and Babot, 2015). The oldest record of the genus, a mandibular fragment of M. catamarcensis, is known from ?early Miocene levels exposed at Mendoza Province, Argentina (see Garrido et al [2014] and García-López and Babot [2015]), and the more recent records are known from the late Pliocene-early Pleistocene (M. bolivianus; Marplatan SALMA, probably Vorohuean subage; and early Pleistocene (M. reigi; Marplatan SALMA, Sanandresian subage; Cione and Tonni, 2005;Cione et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…The dental features that define Microtragulus are the presence of a distinct ectoflexid (labial groove) separating the trigonid from the talonid and absent or vestigial entoflexid (lingual groove) in m1, trigonid with a dominant metaconid, lower ectostylid and protoconid pointing mesiolabially and separated from the ectostylid by a groove (in m1 and/or m2), reduced talonid with a distinctive tongue-like hypoconid in m1-2, well-developed entoconid, and hypoconulid absent or vestigial, and reduced m4, both in length and width, bearing a vestigial talonid separated from the trigonid by ectoflexid and entoflexid. Regarding the upper dentition, the distinctive features include a reduced StE in M1, poorly-developed paracone coalescent with metacone, reduced mesiolabial lobe in M2 and M3, and convex labial outline, particularly in M2 (García-López and Babot, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…The genus was initially defined based on the morphology of its lower molars (Simpson, 1970a), but additional characters of the upper dentition have been recently described for this taxon (García-López and Babot, 2015). The dental features that define Microtragulus are the presence of a distinct ectoflexid (labial groove) separating the trigonid from the talonid and absent or vestigial entoflexid (lingual groove) in m1, trigonid with a dominant metaconid, lower ectostylid and protoconid pointing mesiolabially and separated from the ectostylid by a groove (in m1 and/or m2), reduced talonid with a distinctive tongue-like hypoconid in m1-2, well-developed entoconid, and hypoconulid absent or vestigial, and reduced m4, both in length and width, bearing a vestigial talonid separated from the trigonid by ectoflexid and entoflexid.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Redescription of the argyrolagid Microtragulus bolivianus (Metatheria, Polydolopimorphia, Bonapartheriiformes) based on new remains from Northwestern Ar

Babot

García-López

2016

Palaeontologia Electronica

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Section: Descriptionmentioning

confidence: 48%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Redescription of the argyrolagid Microtragulus bolivianus (Metatheria, Polydolopimorphia, Bonapartheriiformes) based on new remains from Northwestern Ar

Babot

García-López

2016

Palaeontologia Electronica

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The Skull of Epidolops ameghinoi from the Early Eocene Itaboraí Fauna, Southeastern Brazil, and the Affinities of the Extinct Marsupialiform Order Polydolopimorphia

Beck

2016

J Mammal Evol

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The skull of the polydolopimorphian marsupialiform Epidolops ameghinoi is described in detail for the first time, based on a single well-preserved cranium and associated left and right dentaries plus additional craniodental fragments, all from the early Eocene (53–50 million year old) Itaboraí fauna in southeastern Brazil. Notable craniodental features of E. ameghinoi include absence of a masseteric process, very small maxillopalatine fenestrae, a prominent pterygoid fossa enclosed laterally by a prominent ectopterygoid crest, an absent or tiny transverse canal foramen, a simple, planar glenoid fossa, and a postglenoid foramen that is immediately posterior to the postglenoid process. Most strikingly, the floor of the hypotympanic sinus was apparently unossified, a feature found in several stem marsupials but absent in all known crown marsupials. “Type II” marsupialiform petrosals previously described from Itaboraí plausibly belong to E. ameghinoi; in published phylogenetic analyses, these petrosals fell outside (crown-clade) Marsupialia. “IMG VII” tarsals previously referred to E. ameghinoi do not share obvious synapomorphies with any crown marsupial clade, nor do they resemble those of the only other putative polydolopimorphians represented by tarsal remains, namely the argyrolagids. Most studies have placed Polydolopimorphia within Marsupialia, related to either Paucituberculata, or to Microbiotheria and Diprotodontia. However, diprotodonty almost certainly evolved independently in polydolopimorphians, paucituberculatans and diprotodontians, and Epidolops does not share obvious synapomorphies with any marsupial order. Epidolops is dentally specialized, but several morphological features appear to be more plesiomorphic than any crown marsupial. It seems likely Epidolops that falls outside Marsupialia, as do morphologically similar forms such as Bonapartherium and polydolopids. Argyrolagids differ markedly in their known morphology from Epidolops but share some potential apomorphies with paucituberculatans. It is proposed that Polydolopimorphia as currently recognised is polyphyletic, and that argyrolagids (and possibly other taxa currently included in Argyrolagoidea, such as groeberiids and patagoniids) are members of Paucituberculata. This hypothesis is supported by Bayesian non-clock phylogenetic analyses of a total evidence matrix comprising DNA sequence data from five nuclear protein-coding genes, indels, retroposon insertions, and morphological characters: Epidolops falls outside Marsupialia, whereas argyrolagids form a clade with the paucituberculatans Caenolestes and Palaeothentes, regardless of whether the Type II petrosals and IMG VII tarsals are used to score characters for Epidolops or not. There is no clear evidence for the presence of crown marsupials at Itaboraí, and it is possible that the origin and early evolution of Marsupialia was restricted to the “Austral Kingdom” (southern South America, Antarctica, and Australia).Electronic supplementary materialThe online version of this article (doi:10.1...

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Paleobiology of Argyrolagus (Marsupialia, Argyrolagidae): an astonishing case of bipedalism among South American mammals

Abello

Candela

2019

J Mammal Evol

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Argyrolagus constitutes, both for its craniodental and postcranial anatomy, one of the most notably specialized South American Neogene metatherians. Differentiating it from any other South American mammal, bipedal jumping has been proposed for Argyrolagus, even though this hypothesis was not supported by morphofunctional studies. Here, we describe the postcranium of A. scaglai (from the Pliocene of Argentina), perform a functional analysis, and interpret it against a varied background of locomotor adaptations of extant mammals. The configuration of joints, the degree of development and location of muscular insertions were mainly analyzed, and functional indices were evaluated. This study indicates that Argyrolagus had stabilized glenohumeral and humeroulnar joints, a great development of the arm retractors, flexors-extensors of the digits, pronator, and supinator muscles, low restrictive humeroradial joint, powerful extensor muscles of the hip, knee, and ankle, good development of the iliac muscle, and restrictive hind limb joints. Joint configurations are interpreted to be optimal to resist the impacts during jumping, avoiding dislocation, compatible with digging activity. A compromise between the capacities to dig and manipulate objects is inferred. It is concluded that Argyrolagus had bipedal jumping locomotion as well as good capacity to dig, constituting an astonishing case of convergence with the small bipedal rodents and small Australian macropodids. We suggest that bipedal jumping in Miocene and Pliocene argyrolagids should not be necessarily related to a particular arid environment. Finally, we evaluate the importance of postcranial features to understand the phylogenetic relationships of Argyrolagidae in a comprehensive phylogeny of Metatheria.

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A Late Miocene Argyrolagidae (Mammalia, Metatheria, Bonapartheriiformes) from Northwestern Argentina

Cited by 11 publications

References 13 publications

Redescription of the argyrolagid Microtragulus bolivianus (Metatheria, Polydolopimorphia, Bonapartheriiformes) based on new remains from Northwestern Ar

Redescription of the argyrolagid Microtragulus bolivianus (Metatheria, Polydolopimorphia, Bonapartheriiformes) based on new remains from Northwestern Ar

The Skull of Epidolops ameghinoi from the Early Eocene Itaboraí Fauna, Southeastern Brazil, and the Affinities of the Extinct Marsupialiform Order Polydolopimorphia

Paleobiology of Argyrolagus (Marsupialia, Argyrolagidae): an astonishing case of bipedalism among South American mammals

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