Craniodental Morphology and Phylogeny of Marsupials

Beck, Robin M. D.; Voss, Robert S.; Jansa, Sharon A.

doi:10.1206/0003-0090.457.1.1

Cited by 48 publications

(87 citation statements)

References 784 publications

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“…The parsimony-based 50% majority-consensus tree of discrete data outperformed most GMM-based analyses. However, as with the GMM-based trees, discrete-based trees derived from the basicranial dataset had substantially lower similarity to the reference tree, whereas the dataset of all characters (the full matrix from [36]) resulted in a markedly better-performing tree.…”

Section: Resultsmentioning

confidence: 99%

“…To compare the performance of our GMM-based trees with trees based on discrete characters, we also produced phylogenetic trees based on the discrete morphological character dataset of [36]. We partitioned this dataset into: (1) a dataset comprising basicranial characters, excluding four characters relating to the ossicles, resulting in 38 characters that correspond to characters 47–56 and 67–88 of the original list of [36]; (2) a dataset comprising characters from the remainder of the cranium, resulting in 53 characters that correspond to characters 1–46 and 89–95 of the original list of [36]; (3) a dataset that corresponds to the original, ‘full’ 180 character dataset of [36], which comprises cranial, mandibular and dental characters. These discrete datasets comprised 144 taxa [36], but only 45 of these were comparable (even when using congenerics) to the 57 in the GMM dataset.…”

Section: Methodsmentioning

confidence: 99%

“…Basicranial characters have thus been widely used in morphological phylogenetic analyses of broad-scale mammalian relationships [39,43], as well as less inclusive mammalian clades (e.g. [36,44,45]).…”

Section: Introductionmentioning

confidence: 99%

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Multiple modes of inference reveal less phylogenetic signal in marsupial basicranial shape compared with the rest of the cranium

Weisbecker

Beck

Guillerme

et al. 2023

Phil. Trans. R. Soc. B

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Incorporating morphological data into modern phylogenies allows integration of fossil evidence, facilitating divergence dating and macroevolutionary inferences. Improvements in the phylogenetic utility of morphological data have been sought via Procrustes-based geometric morphometrics (GMM), but with mixed success and little clarity over what anatomical areas are most suitable. Here, we assess GMM-based phylogenetic reconstructions in a heavily sampled source of discrete characters for mammalian phylogenetics—the basicranium—in 57 species of marsupial mammals, compared with the remainder of the cranium. We show less phylogenetic signal in the basicranium compared with a ‘Rest of Cranium’ partition, using diverse metrics of phylogenetic signal ( K mult , phylogenetically aligned principal components analysis, comparisons of UPGMA/neighbour-joining/parsimony trees and cophenetic distances to a reference phylogeny) for scaled, Procrustes-aligned landmarks and allometry-corrected residuals. Surprisingly, a similar pattern emerged from parsimony-based analyses of discrete cranial characters. The consistent results across methods suggest that easily computed metrics such as K mult can provide good guidance on phylogenetic information in a landmarking configuration. In addition, GMM data may be less informative for intricate but conservative anatomical regions such as the basicranium, while better—but not necessarily novel—phylogenetic information can be expected for broadly characterized shapes such as entire bones. This article is part of the theme issue ‘The mammalian skull: development, structure and function’.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Multiple modes of inference reveal less phylogenetic signal in marsupial basicranial shape compared with the rest of the cranium

Weisbecker

Beck

Guillerme

et al. 2023

Phil. Trans. R. Soc. B

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“…In this same analysis, Bobbschaefferia stands out as a plesiomorphic sister group to the rest of the Polydolopimorphia. Recently, Beck (2017) tentatively proposed the existence of a “staggered” lower incisor in specimen MNRJ 2880-V of Epidolops ameghinoi de Paula Couto, 1952 (de Paula Couto, 1952b) on the basis of a single alveolar space (see Beck et al, 2022 for a discussion on the staggered condition among marsupials). On the contrary, we suggest that the condition of Epidolops resembles more that of Bobbschaefferia as well as that of other basal polydolopimorphians; that is, that the lower incisors are aligned rather than one of them being staggered.…”

Section: Resultsmentioning

confidence: 99%

†Estelestes ensis (Mammalia, Metatheria) from the early Eocene of Baja California (Mexico) as a generalized polydolopimorphian

et al. 2023

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Estelestes ensis Novaceck et al., 1991 is a curious Paleogene metatherian mammal recognized on the basis of a single specimen from Baja California (Mexico) in southern North America. It comes from early Eocene (Wasatchian age) levels of the Las Tetas de Cabra Formation at “Marsupial Hill” in the Lomas Las Tetas de Cabra site (also known as Punta Prieta; see Novaceck et al., 1991). The specimen consists of a fragmentary left mandible with the last premolar, the roots of the first two molars, and almost complete last two molars (Fig. 1). It was referred to the Didelphini (Marsupialia, Didelphimorphia, Didelphidae, Didelphinae) even though Novaceck et al. (1991) stated that the overall morphology of the type specimen poses intriguing problems regarding its relationships. For example, the very deep, robust jaw of Estelestes distinguishes it from any other Holarctic “didelphine” (at the time Novaceck et al., 1991 published their work, both the concept and extent of Didelphidae and Didelphinae were much broader than today). Interestingly, they concluded that Estelestes had close affinities with “Mirandotherium” (lapsus calami for Mirandatherium), from the early Eocene of Itaboraí, in southeastern Brazil. “Resemblance between the two taxa is nevertheless striking, once again raising the possibility of close relationships among certain early members of the Northern Hemisphere and South American Didelphinae” (Novaceck et al., 1991, p. 16). The affinities of Mirandatherium are contested, having been regarded as part of the Didelphimorphia (e.g., de Paula Couto, 1952a) or Microbiotheria (e.g., Marshall, 1987; McKenna and Bell, 1997; Oliveira and Goin, 2011), or even as an alphadontian (Carneiro, 2019).

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“…They are thus readily distinguishable from one another. Their last common ancestor probably existed in the later Miocene about 6-8 million years ago (Westerman et al 2016;Kealy and Beck 2017;García-Navas et al 2020;Beck et al 2022), enough time for each to have developed distinct phenotypes in adapting to their arid habitats. Woolley et al (2007) showed that penis structure of the long-tailed dunnart (Form 9) differs from that of all other species of Sminthopsis.…”

Section: Discussionmentioning

confidence: 99%

On the composition of

2023

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Morphological and molecular studies have consistently suggested that Sminthopsis, as currently defined, is rendered paraphyletic by the kultarr (Antechinomys laniger). They have also suggested a sister relationship between the kultarr and the long-tailed dunnart. Based on DNA sequence data from multiple mitochondrial and nuclear gene loci we reassign the long-tailed dunnart (formerly Sminthopsis longicaudata) to Antechinomys. Although there is good evidence of genetic structure within the kultarr (A. laniger), it does not correspond to the two currently recognised subspecies, viz A. laniger laniger and A. l. spenceri. We conclude that Antechinomys consists of two species, A. laniger and A. longicaudatus, consistent with morphology. We suggest that the observed genetic and morphological variation within A. laniger merits a more thorough investigation of more samples from across its range to resolve the taxonomy.

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Craniodental Morphology and Phylogeny of Marsupials

Cited by 48 publications

References 784 publications

Multiple modes of inference reveal less phylogenetic signal in marsupial basicranial shape compared with the rest of the cranium

Multiple modes of inference reveal less phylogenetic signal in marsupial basicranial shape compared with the rest of the cranium

†Estelestes ensis (Mammalia, Metatheria) from the early Eocene of Baja California (Mexico) as a generalized polydolopimorphian

On the composition of

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