Comparative anatomy of the middle ear in some lizard species with comments on the evolutionary changes within Squamata.

The skeleton of the middle ear of lizards is composed of three anatomical elements: columella, extracolumella, and tympanic membrane, with some exceptions that show modifications of this anatomy. The main function of the middle ear is transforming sound waves into vibrations and transmitting these to the inner ear. Most middle ear studies mainly focus on its functional aspects, while few describe the anatomy in detail. In lizards, the morphology of the columella is highly conservative, while the extracolumella shows variation in its presence/absence, size, and the number of processes present on the structure. In this work, we used diaphanized and double-stained specimens of 38 species of lizards belonging to 24 genera to study the middle ear's morphology in a comparative framework. Results presented here indicate more variation in the morphology of the extracolumella than previously known. This variation in the extracolumella is found mainly in the pars superior and anterior processes, while the pars inferior and the posterior process are more constant in morphology. We also provide new information about the shape of gekkotan extracolumella, including traits that are diagnostic for the iguanid and gekkonid middle ear types. The data collected in this study were combined with information from published descriptive works. The new data included here refers to the length of the columella relative to the extracolumella central axis length, the general structure of the extracolumella, and the presence of the internal process. These characters were included in ancestral reconstruction analysis using Bayesian and parsimony approaches. The results indicate high levels of homoplasy in the variation of the columella-extracolumella ratio, providing a better understanding of the ratio variation among lizards. Additionally, the presence of four processes in the extracolumella is the ancestral state for Gekkota, Pleurodonta, and Xantusiidae, and the absence of the internal processes is the ancestral state for Gekkota, Gymnophthalmidae, and Scincidae; despite the fact that these groups convergently develop these character states, they could be used in combination with other characters to diagnose these clades. The posterior extension in the pars superior and an anterior process with some small and sharp projections is also a diagnostic trait for Gekkota. A more accurate description of each process of the extracolumella and its variation needs to be evaluated in a comprehensive analysis, including a greater number of species. Although the number of taxa sampled in this study is small considering the vast diversity of lizards, the results provide an overall idea of the amount of variation of the middle ear while helping to infer the evolutionary history of the lizard middle ear.

A morphological database for Colombian anuran species from conservation-priority ecosystems.

Species traits provide a strong link between an organism's fitness and processes at community and ecosystem levels. However, such data remain scarce for amphibians in the Neotropics. Colombia is the country with the highest number of threatened amphibians and the second greatest number of amphibian species worldwide. We present a data set containing eight morphological traits for 4,623 museum specimens of the seven largest collections in the country corresponding to 293 species of 14 families. The number of measured specimens per species ranged from 1 to 118 individuals with a median of 8 individuals per species. Overall, this database gathered morphological information for 37.6% of Colombian anuran diversity. Species measured were mainly distributed in the high Andean forest, the páramo, and wetland ecosystems, and was part of a national initiative led by the Instituto Alexander von Humboldt. The morphological traits were selected on the basis of their role in species' responses to environmental variability and their contributions to ecosystem processes. These traits were related to habitat use, (forearm length, tibia length, femur length, foot length, and foot webbing), predation and food chains (head width and mouth width), and nutrient recycling (snout-vent length). We expect this data set will be used in studies on functional diversity in amphibians and the development of conservation planning for these taxa. No copyright or proprietary restrictions are associated with the use of this data set other than citation of this Data Paper.

Comparative description and ossification patterns of Dendropsophus labialis (Peters, 1863) and Scinax ruber (Laurenti, 1758) (Anura: Hylidae).

Although comparative studies of anuran ontogeny have provided new data on heterochrony in the life cycles of frogs, most of them have not included ossification sequences. Using differential staining techniques, we observe and describe differences and similarities of cranial and postcranial development in two hylid species, Scinax ruber (Scinaxinae) and Dendropsophus labialis (Hylinae), providing new data of ontogenetic studies in these Colombian species. We examined tadpoles raining from Gosner Stages 25 to 45. We found differences between species in the infrarostral and suprarostral cartilages, optic foramen, planum ethmoidale, and gill apparatus. In both species, the first elements to ossify were the atlas and transverse processes of the vertebral column and the parasphenoid. Both species exhibited suprascapular processes as described in other hylids. Although the hylids comprise a large group (over 700 species), postcranial ossification sequence is only known for 15 species. Therefore, the descriptions of the skeletal development and ossification sequences provided herein will be useful for future analyses of heterochrony in the group.

Osteology of Atelopus muisca (Anura, Bufonidae) from Colombia.

The first comprehensive description of the skeleton of Atelopus muisca Rueda-Almonacid & Hoyos, 1991 (Bufonidae, Anura) from the Chingaza Natural National Park (Colombia) is provided, and comparisons with some characters described for this species by Coloma and related frogs of the group A. ignescens are done. The humerus of male presenting more developed crista ventralis and crista lateralis, and the articulation of the frontoparietal bones showed the presence of sexual dimorphism. These are character not described for species of the genus Atelopus belonging to the group A. ignescens. A. ignescens. Among the other osteological characters we did not find unique feature for the species. 

Staining procedure of cartilage and skeleton in adult bats and rodents / Procedimiento de transparentación para evidenciar cartílago y esqueleto en murciélagos y roedores adultos

Transparency technique to demonstrate cartilage and skeleton has been used from years 70. This consists basically of the muscle digestion through an enzyme (trypsine), and the staining of cartilage and skeleton using alcian blue and alizarin red on specimens previously fixed to formalin. This technique can be used to study the state of the cartilage and the bones in different stages of the development and to observe abnormalitys. Also it can be used to demonstrate museum specimen skeleton preserved in liquid. In this article is showed the application of this technique for the first time in rodents and adult bats, besides some annotations to optimize the procedure.

La técnica de transparentación para evidenciar cartílago y esqueleto ha sido empleada desde los años 70. Esta consiste básicamente en la digestión de músculo a través de una enzima (tripsina), y la tinción del cartílago y el esqueleto usando azul de alcian y rojo de alizarina sobre especímenes previamente fijados en formol. Esta técnica puede emplearse para estudiar el estado del cartílago y los huesos en diferentes etapas del desarrollo y poder observar anormalidades. También puede ser utilizada para evidenciar el esqueleto en especimenes de museo preservados en líquido. En este artículo se muestra la aplicación de esta técnica por primera vez en roedores y murciélagos adultos, además de algunas anotaciones para optimizar el procedimiento.