Geographic distribution and phenetic skull variation in two close species of Graomys (Rodentia, Cricetidae, Sigmodontinae)

Martínez, Juan José; Cola, Valeria Di

doi:10.1016/j.jcz.2011.03.001

Cited by 28 publications

(38 citation statements)

References 51 publications

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“…The overlap areas in morphometric cranial analyses using orthogonal matrix transformation techniques as PCA, irrespective of whether traditional or geometric, have also been identified in other species of other genera and in Calomys (Cordeiro-Estrela et al 2006, Astúa 2009, Bonvicino et al 2010, Martínez and Di Cola 2011. Furthermore, the results obtained in the present study for M1 shape are in agreement with those reported in other studies that showed a divergence in the shape of Calomys skull, but with small areas of intersection (Cordeiro-Estrela et al 2006.…”

Section: Discussionsupporting

confidence: 91%

Taxonomic identification using geometric morphometric approach and limited data: an example using the upper molars of two sympatric species of Calomys (Cricetidae: Rodentia)

Boroni¹,

Lobo²,

Romano³

et al. 2017

Zoologia

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ABSTRACT. The taxonomic identification of micromammals might be complicated when the study material is fragmented, as it is the case with pellets and fossil material. On the other hand, tooth morphology generally provides accurate information for species identification. Teeth preserve notably well, retaining their original morphology, unlike skulls and mandibles, which can get crushed or have missing parts. Here, we explored a geometric morphometrics approach (GM) to identify fragmented specimens of two sympatric Calomys Waterhouse, 1837 species -Calomys tener (Winge, 1888) and Calomys expulsus (Lund, 1841) -using the morphology of intact molars as the basis for identification. Furthermore, we included some specimens of uncertain taxonomic identification to test their affinities and the utility of the shape of the molar to identify incomplete specimens. We evaluated the variations in the shape of the first upper molar (M1) among 46 owl pellets specimens of Calomys, including C. expulsus (n = 15), C. tener (n = 15), and unidentified specimens treated as Calomys sp. (n = 16) through GM analysis using 17 landmarks. The data was explored using PCA, PERMANOVA, and Discriminant analyses over the Procrustes residuals matrix were applied to evaluate inter-and intraspecific shape differences. Also, we evaluated whether allometric shape differences could impact the data, but found no evidence of a correlation between size and shape. Our results support that shape differences in the M1 are effective for discriminating between C. tener and C. expulsus. Moreover, the unidentified specimens do not represent a third shape but could be identified with confidence either as C. tener or C. expulsus. Our results show that even with fragmentary materials, GM is a feasible and useful tool for exploring inter-specific shape differences and assisting in taxonomic identification as a complement to traditional qualitative description of diagnostic features in poorly preserved specimens.

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Section: Discussionsupporting

confidence: 91%

Taxonomic identification using geometric morphometric approach and limited data: an example using the upper molars of two sympatric species of Calomys (Cricetidae: Rodentia)

Boroni¹,

Lobo²,

Romano³

et al. 2017

Zoologia

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“…Myriad studies have shown that shape variation follows environmental gradients. Climatic factors explain the skull shape variation of several species of capuchin monkeys (Cáceres et al 2014) and Graomys (Martínez and Cola 2011) across South America. Climatic factors explain the skull shape variation of several species of capuchin monkeys (Cáceres et al 2014) and Graomys (Martínez and Cola 2011) across South America.…”

Section: Introductionmentioning

confidence: 99%

Geometric morphometrics meets metacommunity ecology: environment and lineage distribution affects spatial variation in shape

et al. 2017

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Patterns of univariate trait variation across metacommunities are widely explored, as are searches for their underlying causes. Surprisingly, patterns of multivariate shape remain unknown, and the search for drivers of functional traits of communities often neglect the biogeographical distribution of phylogenetic clades. Our aim was to investigate multivariate shape distribution across metacommunities and to determine the main environmental drivers of shape beyond/taking into account the phylogenetic distribution of lineages. We obtained mean skull and mandible shape for 228 species of Neotropical sigmodontine rodents through geometric morphometrics (GM), and then calculated mean shapes for 1°  1° cells across the Neotropics based on the incidence of sigmodontines. We investigated the effects of lineage distribution on mean trait variation by using phylogenetic fuzzy weighting to calculate principal coordinates of phylogenetic structure (PCPS). Effects of environmental variables on shape variation incorporating phylogenetic composition were realized through redundancy analysis. We found that the different distributions of major lineages throughout the Neotropics were responsible for much of the mean shape variation. The association of landscape features with tribal groupings (Oryzomyini with Amazonia and Phyllotini and Abrotrichini with the Andes) were standouts. Environmental variables and lineage distribution explain the same (i.e. shared) portion of shape variation, suggesting phylogenetic niche conservatism at the metacommunity level. Seasonality in temperature and land cover were the best environmental predictors of mean shape: larger tympanic bullae, incisive foramina, and check teeth are all associated with highly seasonal and less vegetated areas. Our new approach of using GM shape across metacommunities was demonstrably useful in understanding largescale biogeographical patterns of shape variation and identifying its underlying causes. The overlap between environmental variables and phylogenetic lineage distribution suggests that a process of niche conservatism is likely: the phenotype-environment correlation is mediated by the differential biogeographical distribution of the main clades.

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“…However, skeletal variations, sometimes even in the skull, exist among a group of individuals (Hanken, 1984;Shubin et al, 1995;Martínez and Cola, 2011). So, we suggest more samples need to be checked and more attention to be paid on skeletal variation when using them in a taxonomic diagnosis.…”

Section: Discussionmentioning

confidence: 97%

Discovery of an Internasal Bone in <I>Hynobius maoershanensis</I> (Urodela: Hynobiidae)

Xiong¹,

Liu²,

Zeng³

2011

Asian Herpetological Research

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Geographic distribution and phenetic skull variation in two close species of Graomys (Rodentia, Cricetidae, Sigmodontinae)

Cited by 28 publications

References 51 publications

Taxonomic identification using geometric morphometric approach and limited data: an example using the upper molars of two sympatric species of Calomys (Cricetidae: Rodentia)

Taxonomic identification using geometric morphometric approach and limited data: an example using the upper molars of two sympatric species of Calomys (Cricetidae: Rodentia)

Geometric morphometrics meets metacommunity ecology: environment and lineage distribution affects spatial variation in shape

Discovery of an Internasal Bone in <I>Hynobius maoershanensis</I> (Urodela: Hynobiidae)

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