Following the Footsteps of the South American Equus: Are Autopodia Taxonomically Informative?

Machado, Helena; Grillo, Orlando Nelson; Scott, Eric; Avilla, Leonardo dos Santos

doi:10.1007/s10914-017-9389-6

Cited by 16 publications

(32 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The bivariate analysis was carried out on the tooth measurements that are more related to the dimensions of occlusal surface and was run in Microsoft Excel (2010 version). Multivariate analyses included PCA and CVA, and for the PCA the problem of missing data was handled by the Iterative Imputation method (Hammer, 2012;Machado et al, 2018).…”

Section: Methodsmentioning

confidence: 99%

“…The methodology used in the autopodial analysis took into consideration the latest proposition of Prado and Alberdi (2017) and followed the methods and reasoning of Machado et al (2018). We analyzed 29 metatarsi (MTIII), 33 metacarpi (MCIII) and 54 first phalanges (IPHIII) of E. andium; 53 MTIII, 47 MCIII, and 70 IPHIII of E. insulatus; and 20 MTIII, 14 MCIII, and 28 IPHIII of E. neogeus.…”

Section: Methodsmentioning

confidence: 99%

“…Traditionally, five species have been recognized on this continent (Prado and Alberdi, 1994;Alberdi and Prado, 2004), but recently the number has been reduced to three: Equus neogeus, E. insulatus, and E. andium (Prado and Alberdi, 2017). However, Machado et al (2018) suggested the possibility that South America might have had only a single species of native Equus, namely E. neogeus.…”

Section: Introductionmentioning

confidence: 99%

“…No clear, objective and certain basis for distinguishing between the three species has been established and Machado et al (2018) and Machado (2018) showed that the characters used previously are not taxonomically valid. Furthermore, when a larger dataset is analyzed, there is a great overlap among all three Equus species in morphospace (Machado, 2018;Machado et al, 2018). The most plausible interpretation is that Equus was probably represented in South America by only a single species, E. neogeus.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Diversity of South American Equus: Did Size Really Matter?

Machado

Avilla

2019

Front. Ecol. Evol.

Self Cite

View full text Add to dashboard Cite

The extant horse genus Equus originated in North America, probably during the late Miocene/early Pliocene, and its entrance into South America was possibly related to one of the last four stages of the Great American Biotic Interchange. Nonetheless, the genus had a broad geographic distribution throughout South America. Five species of Equus were traditionally recognized on this continent, although recently they have been synonymized into three: Equus neogeus, E. insulatus, and E. andium. However, the diagnoses of the three species are still unclear and a recent study showed that the characters previously used are not taxonomically valid, with the implication that in South America, Equus was represented by a single species, E. neogeus. This contribution is intended to update current knowledge on the diversity of South American Equus. Accordingly, a synthesis of prior knowledge as well as an update on the fossil distribution of Equus is presented here. Dental analyses were carried out, and the results revealed a clear overlap among the currently recognized species. Characters of the autopodia were also reanalyzed with greater sampling, and the results once again confirmed that a single species was present in South America. The update of fossil occurrences increased knowledge of the geographical distribution of the genus in South America. There are records throughout almost the entire continent, except for regions in the Amazonian rain forest, at latitudes south of 40 • S, and at altitudes above 3,000 m. Furthermore, evaluating the new data with reference to geography revealed that E. neogeus formed a smooth cline, in which variation was gradual and continuous. It is also inferred that observed phenotypic variation is probably related to topography.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Diversity of South American Equus: Did Size Really Matter?

Machado

Avilla

2019

Front. Ecol. Evol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Por lo tanto, consideramos a E. francisci y E. cedralensis como potenciales especies diferentes que se distinguen únicamente a nivel de los metápodos. Recientemente, Machado et al (2017) analizaron los autopodios de las especies de Equus de Sudamérica y observaron un continuo de variación gradual que representa una clina. Un análisis detallado de estos elementos apendiculares en E. francisci y E. cedralensis permitirá corroborar si en realidad son especies diferentes.…”

Section: Consideraciones Taxonómicasunclassified

Revisión taxonómica de los équidos del Pleistoceno de México con base en la morfología dental

Priego-Vargas

Bravo-Cuevas

Jiménez-Hidalgo

2017

Rev. bras. paleontol.

View full text Add to dashboard Cite

-TAXONOMIC REVIEW OF THE PLEISTOCENE EQUIDS FROM MEXICO BASED ON DENTAL MORPHOLOGY.A quantitative and qualitative evaluation of the dental traits of five horse species from 15 fossiliferous areas from the Pleistocene of Mexico was performed. The purpose of this study was to evaluate whether Equus mexicanus, E. conversidens, E. excelsus, E. francisci (= E. tau) and E. cedralensis show particular dental morphologies (measurements and occlusal morphology of the molariform) that provide information of systematic significance. To this end, premolars and molars of adult individuals were used to evaluate a set of ten quantitative variables that were analyzed by bivariate and multivariate methods; also, 13 qualitative variables were used to estimate the frequency in the configuration and development degree of the enamel pattern on the occlusal surface for each species. Our results indicate that 60% of the quantitative variables and 40% of the qualitative provide information to distinguish dental morphologies. Based on measures and the enamel pattern the following specific characteristics were recognized: E. mexicanus: large-size occlusal area and relatively complex enamel pattern, E. conversidens: medium-size and moderately complex occlusal enamel and E. francisci: small-size and relatively simple enamel pattern on the occlusal surface. Concerning E. excelsus and E. cedralensis, their dental morphology is closely similar to those of E. conversidens and E. francisci respectively. The observed dental morphology of the Mexican specimens of E. excelsus indicates that part of those should be reconsidered as E. conversidens and part as E. mexicanus. Nevertheless, E. francisci and E. cedralensis are different species that can be recognized by limb characters rather than dental traits. Furthermore, the developing of particular dental patterns in these species is a factor that allowed their coexistence in Mexico during the Pleistocene.Key words: dental morphology, Equidae, Equus, taxonomy, Pleistocene, Mexico.RESUMO -No presente estudo foi realizada uma avaliação quantitativa e qualitativa das características dentárias de cinco espécies de cavalos de 15 áreas fossilíferas do Pleistoceno mexicano. Os objetivos do estudo foram de avaliar se Equus mexicanus, E. conversidens, E. excelsus, E. francisci (= E. tau) e E. cedralensis mostram morfologias dentárias particulares (medidas e morfologia oclusal de molariformes) que forneçam informações de importância sistemática. Para tal, pré-molares e molares de indivíduos adultos foram utilizados para avaliar um conjunto de dez variáveis quantitativas que foram analisadas por métodos bivariantes e multivariantes. Também foram utilizadas 13 variáveis qualitativas para estimar a frequência no grau de configuração e desenvolvimento do padrão de esmalte na superfície oclusal para cada espécie. Os resultados indicaram que 60% das variáveis quantitativas e 40% das qualitativas proveram informações para distinguir morfologias dentárias. De acordo com as medidas e o padrão do esmalte foram...

show abstract