RESUMO
The skink genus Marisora ranges from Mexico to northern South America and occurs on some islands in the Caribbean Sea. We conducted a revision of the genus Marisora from Mexico and Central America, using new morphological and molecular data, and find support for the five previously described species (Marisora alliacea, M.aurulae, M. brachypoda, M. magnacornae, and M. roatanae) and describe four new species: Marisora lineola sp. nov., M. aquilonaria sp. nov., M. syntoma sp. nov., and M. urtica sp. nov. We show that two species previously known only from Central American islands, M. magnacornae and M. roatanae, also occur on the adjacent mainland and that two species recently placed in Alinea belong to this evolutionary clade: Marisora berengerae n. comb. and Marisora pergravis n. comb. Together with M. falconensis and M. unimarginata, these 13 species of Marisora arose mostly in the Pliocene and are largely allopatric but are sympatric and nearly sympatric at several locations in Central America where they maintain their morphological and genetic distinctiveness.
Assuntos
Lagartos , Distribuição Animal , Animais , América Central , MéxicoRESUMO
Integrative taxonomy has been generally considered as a goal in systematics for more than a decade. Here, we employed environmental, molecular, and morphological data to evaluate the species boundaries within the short-nosed skink Plestiodon brevirostris from south-central Mexico, one member of the morphologically conservative P. brevirostris group. Our molecular dataset includes one mitochondrial and two nuclear loci. The mitochondrial fragment includes the full length of the gene coding for the NADH dehydrogenase subunit 1 protein, a segment of the gene coding for 16S ribosomal RNA, and flanking tRNAs. The nuclear dataset includes fragments of the genes coding for the megakaryoblastic leukemia 1 and RNA fingerprint 35 proteins. We employed phylogenetic reconstruction, analyses of population structure and morphological variation, and species delimitation methods (including the integration of the three kinds of data in a unified probabilistic framework) to evaluate species limits. Our results suggest that P. brevirostris represents four distinct species. The information provided by each kind of data allowed us to discern between alternative explanations for the observed patterns of geographic structure. Two of the newly recognized lineages are poorly differentiated morphologically but apparently differ in environmental preferences and are allopatric. Additionally, one lineage is microendemic and parapatric with respect to another one. Moreover, our phylogenetic analyses suggest that other taxa within the P. brevirostris group may represent species complexes. We discuss our results in the context of integrative species delimitation.
Assuntos
Lagartos/classificação , Filogenia , Animais , Teorema de Bayes , DNA Mitocondrial/genética , Loci Gênicos , Geografia , Lagartos/genética , México , Mitocôndrias/genética , RNA Ribossômico 16S/genética , Reprodutibilidade dos Testes , Especificidade da Espécie , Fatores de TempoRESUMO
La proporción entre el segundo y cuarto dígito (2D/4D) ha sido bien estudiada como un dimorfismo sexual que puede resultar de los efectos androgénicos prenatales sobre la expresión de los genes homeobox. Se ha encontrado que este dimorfismo exhibe patrones filogenéticos en el cual las hembras tienen mayor proporción entre dígitos en especies mamíferas y menor proporción entre dígitos en especies de aves y reptiles. Este estudio midió los dígitos segundo y cuarto de todos las extremidades, en 25 especímenes machos y 25 especímenes hembras adultos de Gonatodes albogularis. Se determinó que no existían diferencias significativas entre la proporción (2D/4D) en machos y hembras como dimorfismo sexual de la especie. Estos resultados indican que esta especie de lagartija arbórea se desvía de la proporción entre dígitos mostrada por especies diápsida. Posibles factores ambientales asociados son discutidos.
The second-to-fourth digit ratio (2D/4D) is a well-studied sexual dimorphism that likely arises as a result of prenatal androgenic effects on homeobox gene expression. This dimorphism has been found to exhibit interesting phylogenetic patterns in which females have larger ratios than males among most mammalian species and males have larger ratios than females in most avian and reptilian species. This study measured the second and fourth digits of all limbs from 25 adult males and 25 adult females of Gonatodes albogularis. There were no significant differences between the (2D/4D) for gender as sexual dimorphism of the species. These results indicate that this species of tree lizard deviates from the ratio shown by diapsid species. Possible associated environmental factors are discussed.
RESUMO
La proporción entre el segundo y cuarto dígito (2D/4D) ha sido bien estudiada como un dimorfismo sexual que puede resultar de los efectos androgénicos prenatales sobre la expresión de los genes homeobox. Se ha encontrado que este dimorfismo exhibe patrones filogenéticos en el cual las hembras tienen mayor proporción entre dígitos en especies mamíferas y menor proporción entre dígitos en especies de aves y reptiles. Este estudio midió los dígitos segundo y cuarto de todos las extremidades, en 25 especímenes machos y 25 especímenes hembras adultos de Gonatodes albogularis. Se determinó que no existían diferencias significativas entre la proporción (2D/4D) en machos y hembras como dimorfismo sexual de la especie. Estos resultados indican que esta especie de lagartija arbórea se desvía de la proporción entre dígitos mostrada por especies diápsida. Posibles factores ambientales asociados son discutidos.
The second-to-fourth digit ratio (2D/4D) is a well-studied sexual dimorphism that likely arises as a result of prenatal androgenic effects on homeobox gene expression. This dimorphism has been found to exhibit interesting phylogenetic patterns in which females have larger ratios than males among most mammalian species and males have larger ratios than females in most avian and reptilian species. This study measured the second and fourth digits of all limbs from 25 adult males and 25 adult females of Gonatodes albogularis. There were no significant differences between the (2D/4D) for gender as sexual dimorphism of the species. These results indicate that this species of tree lizard deviates from the ratio shown by diapsid species. Possible associated environmental factors are discussed.