Papers by David A Sanchez
Evolutionary Systematics, 2022
We describe a new species of microhylid frog of the genus Synapturanus from the lower Putumayo ba... more We describe a new species of microhylid frog of the genus Synapturanus from the lower Putumayo basin in Loreto, Perú. Specimens inhabited the soils of stunted pole forests growing on peat. The new species is distinguished from other species of Synapturanus through morphology, genetics, and acoustic characteristics. This species differs from most nominal congeners by having a head flat in lateral view (vs convex in the rest of species), a characteristic only shared by S. rabus and S. salseri. The new species can be distinguished from S. rabus and S. salseri by a combination of morphological characters and by having an advertisement call with a note length of 0.05–0.06 seconds (vs 0.03 seconds in S. rabus) and a dominant frequency ranging from 1.73 to 1.81 kHz (vs 1.10–1.47 kHz in S. salseri). Principal component analyses of 12 morphological characters and three acoustic variables further support differences between the new species and its described and undescribed congeners.
Copeia, 2010
The morphology of the larval oral disc, nostril, skin, and vent tube of tadpoles of Andean stream... more The morphology of the larval oral disc, nostril, skin, and vent tube of tadpoles of Andean stream dwelling Hyloscirtus (Hylidae: Hylinae: Cophomantini) was studied. A wide variation of larval tooth row number is compiled from literature and from observations of Colombian specimens in museums. The marginal papillae are precursors of the tooth rows. The submarginal papillae are organized parallel to the anterior tooth rows and are precursors of the flaps or accessory tooth rows. There is no particular tooth row formula, and no particular marginal papillae arrangement for a species or a recognized species group in the genus. The number of tooth rows and of accessory tooth rows increase with development and size of the tadpole. Two species groups are identified inside Hyloscirtus based on the tooth row formulae, upper jaw sheath morphology, and shape of the nostril of tadpoles. The two groups identified here are different from the three species groups currently recognized for the genus and show well-delimited geographic distributions through the northern Andes. Nostril shape of one species group of Hyloscirtus recognized here is putatively present in all Cophomantini. Spots on the venter associated with neuromasts are present in all the tadpoles of Hyloscirtus studied, and presumably the same as the ones found in some Hypsiboas and Aplastodiscus (Hylidae: Hylinae: Cophomantini). A saccular structure associated with the vent tube covers developing hindlimbs of all tadpoles of Hyloscirtus, and is proposed as a morphological synapomorphy of the genus.
Zootaxa, 2013
Tadpoles in the superfamily Dendrobatoidea (families Aromobatidae and Dendrobatidae), housed in z... more Tadpoles in the superfamily Dendrobatoidea (families Aromobatidae and Dendrobatidae), housed in zoological collections or illustrated in publications, were studied. For the most part, tadpoles of species within the family Aromobatidae, the subfamilies Colostethinae and Hyloxalinae (of the family Dendrobatidae), and those of the genus Phyllobates, Dendrobatinae (Dendrobatidae) have slender anterior jaw sheaths with a medial notch and slender lateral processes, triangular fleshy projections on the inner margin of the nostrils and digestive tube with constant diameter and color and its axis sinistrally directed, concealing the liver and other organs. These morphologies are different from the ones observed in tadpoles of species included in the Dendrobatinae (minus Phyllobates). Exceptions to these morphological arrangements are noted, being the digestive system arrangement and the nostril ornamentation more plastic than the shape of the upper jaw sheath. Tadpoles of all species of the ...
PeerJ, 2020
Background Pandi’s mushroom-tongue salamander (Bolitoglossa pandi) is one of the threatened amphi... more Background Pandi’s mushroom-tongue salamander (Bolitoglossa pandi) is one of the threatened amphibians in South America, as well as a flagship species for the Colombian conservation agenda. This species is endemic to the Andean cloud forests of the western slope of the Cordillera Oriental of Colombia, occurring only in the department of Cundinamarca within a narrow elevational range. At night, B. pandi can be seen perching on the upper side of leaves at heights ranging from ground level to 2.5 m. During the day, it can be found under leaf litter or cover objects. Few studies have provided relevant information that can help the Colombian government to formulate lines of action for the conservation of this species; consequently, its threat assessments so far have been based on very limited information. Methods We conducted surveys for salamanders in four municipalities of Cundinamarca, Colombia, using two approaches: visual encounter surveys (Guaduas and Villeta) and the basic samplin...
South American Journal of Herpetology, 2018
We present a molecular phylogenetic analysis of the hylid tribe Hylini, with the goals of testing... more We present a molecular phylogenetic analysis of the hylid tribe Hylini, with the goals of testing the monophyly of the genera Duellmanohyla, Isthmohyla, and Ptychohyla and providing a discussion on the monophyly of Bromeliohyla, Charadrahyla, Ecnomiohyla, Exerodonta, Megastomatohyla, and Sarcohyla. Our results indicate the paraphyly of Ptychohyla, with Bromeliohyla and Duellmanohyla nested within it, and, as in previous analyses, the paraphyly of Duellmanohyla (due to Ptychohyla legleri and P. salvadorensis being nested within it). To resolve this situation, we restrict the contents of Ptychohyla, redelimit those of Duellmanohyla and Bromeliohyla, and erect two new genera, one to include the former Ptychohyla panchoi and P. spinipollex, and the other for the former Ptychohyla acrochorda, P. sanctaecrucis, P. zoque, and tentatively, P. erythromma. Exerodonta as currently defined is not monophyletic, inasmuch as Exerodonta juanitae is nested within Charadrahyla. Consequently, we transfer this species and, tentatively, E. pinorum to Charadrahyla. Also, we discuss some possible taxonomic problems within Exerodonta. Our results indicate that Isthmohyla is polyphyletic, the bromeliad-dwelling Isthmohyla melacaena being the sister taxon of our only exemplar of Bromeliohyla, B. bromeliacia. For this reason, we transfer I. melacaena to Bromeliohyla, rendering Isthmohyla monophyletic. The former Isthmohyla pictipes Group is shown to be paraphyletic due to having the non-monophyletic I. pseudopuma Group within it. Accordingly, we recognize a redelimited I. pseudopuma Group (contents: I. infucata and I. pseudopuma), an I. zeteki Group (contents: I. picadoi and I. zeteki), and a newly defined I. tica Group (contents: I. angustilineata, I. calypsa, I. debilis, I. graceae, I. lancasteri, I. pictipes, I. tica, I. rivularis, and, tentatively, I. insolita and I. xanthosticta). The three groups of Isthmohyla are supported by molecular evidence with jackknife support values > 90%, and two of them by putative morphological synapomorphies. We discuss the recognition of Dryophytes, Hyliola, Rheohyla, and Sarcohyla and whether it is useful to recognize Anotheca, Diaglena, and Triprion as three distinct, monotypic genera. Finally, we discuss a recent taxonomic proposal involving changes in rank and from ranked to unranked names in hylids that overall we consider to have been poorly justified and only superficially discussed.
The morphology of the larval oral disc, nostril, skin, and vent tube of tadpoles of Andean stream... more The morphology of the larval oral disc, nostril, skin, and vent tube of tadpoles of Andean stream dwelling Hyloscirtus (Hylidae: Hylinae: Cophomantini) was studied. A wide variation of larval tooth row number is compiled from literature and from observations of Colombian specimens in museums. The marginal papillae are precursors of the tooth rows. The submarginal papillae are organized parallel to the anterior tooth rows and are precursors of the flaps or accessory tooth rows. There is no particular tooth row formula, and no particular marginal papillae arrangement for a species or a recognized species group in the genus. The number of tooth rows and of accessory tooth rows increase with development and size of the tadpole. Two species groups are identified inside Hyloscirtus based on the tooth row formulae, upper jaw sheath morphology, and shape of the nostril of tadpoles. The two groups identified here are different from the three species groups currently recognized for the genus and show well-delimited geographic distributions through the northern Andes. Nostril shape of one species group of Hyloscirtus recognized here is putatively present in all Cophomantini. Spots on the venter associated with neuromasts are present in all the tadpoles of Hyloscirtus studied, and presumably the same as the ones found in some Hypsiboas and Aplastodiscus (Hylidae: Hylinae: Cophomantini). A saccular structure associated with the vent tube covers developing hindlimbs of all tadpoles of Hyloscirtus, and is proposed as a morphological synapomorphy of the genus. Se estudió la morfología del disco oral, narinas, piel, y tubo cloacal en renacuajos andinos de quebrada Hyloscirtus (Hylidae: Hylinae: Cophomantini). Una amplia variació n del nú mero de hileras de dientes larvales se recopila y describe a partir de literatura y observaciones en ejemplares de museo colombianos. Las papilas marginales son precursoras de las hileras de dientes, y las papilas submarginales se organizan paralelas a las hileras de dientes anteriores y son precursoras de las hileras de dientes accesorias o flaps. Ninguna especie o grupo de especies reconocidas en el gé nero tiene una fó rmula dental larval o un arreglo de papilas marginales particular. El nú mero de hileras de dientes crece a medida que el renacuajo crece y se desarrolla. Se pueden identificar dos grupos de especies dentro de Hyloscirtus usando la fó rmula dental, la forma del pico anterior y la forma de las narinas de las larvas. Estos dos grupos son diferentes a los tres grupos de especies actualmente reconocidos dentro del gé nero y muestran una distribució n geográ fica bien delimitada en el norte de Los Andes. La forma de las narinas de uno de los grupos de especies acá reconocidos está putativamente presente en todos los Cophomantini. Unos puntos redondos en el vientre asociados a neuromastos está n presentes en todos los renacuajos de Hyloscirtus estudiados, y presuntamente son los mismos que se encuentran en especies de Hypsiboas y Aplastodiscus (Hylidae: Hylinae: Cophomantini). Una estructura en forma de bolsa cubre las patas traseras en desarrollo de todos los renacuajos de Hyloscirtus, y se propone como sinapomorfía morfoló gica del gé nero.
Tadpoles in the superfamily Dendrobatoidea (families Aromobatidae and Dendrobatidae), housed in z... more Tadpoles in the superfamily Dendrobatoidea (families Aromobatidae and Dendrobatidae), housed in zoological collections or illustrated in publications, were studied. For the most part, tadpoles of species within the family Aromobatidae, the subfamilies Colostethinae and Hyloxalinae (of the family Dendrobatidae), and those of the genus Phyllobates, Dendrobatinae (Dendrobatidae) have slender anterior jaw sheaths with a medial notch and slender lateral processes, triangular fleshy projections on the inner margin of the nostrils and digestive tube with constant diameter and color and its axis sinistrally directed, concealing the liver and other organs. These morphologies are different from the ones observed in tadpoles of species included in the Dendrobatinae (minus Phyllobates). Exceptions to these morphological arrangements are noted, being the digestive system arrangement and the nostril ornamentation more plastic than the shape of the upper jaw sheath. Tadpoles of all species of the Dendrobatoidea have similar disposition of digestive organs in early stages, but differentiate in late stages of development. Classifying the upper jaw sheath into the two recognized states is possible from very early stages of development, but gut disposition and nostril ornamentation cannot be determined until late in development, making classification and taxonomic assignment of tadpoles based on these morphological features challenging. Resumen Se estudiaron las larvas de ranas de especies de la superfamilia Dendrobatoidea (familias Aromobatidae y Dendrobatidae) preservadas en colecciones zoológicas o ilustradas en la literatura. De manera general, los renacuajos de las especies de la familia Aromobatidae, las subfamilias Colostethinae e Hyloxalinae (familia Dendrobatidae) y del género Phyllobates (subfamilia Dendrobatinae) tienen queratostomas superiores delgados, con una muesca medial y con procesos laterales delgados, una proyección carnosa triangular en el margen interno de las narinas y un tubo digestivo con diámetro y color constantes, y su eje dirigido al lado izquierdo del vientre ocultando el hígado y otros órganos. Estas morfologías son diferentes a las observadas en renacuajos de especies de la subfamilia Dendrobatinae (sin incluir Phyllobates). Las excepciones a estas distribuciones de morfologías se anotan, siendo la disposición del sistema digestivo y la presencia de las proyecciones triangulares en los márgenes de las narinas más plásticas que la forma del queratostoma anterior. Los renacuajos de todas las especies de la superfamilia Dendrobatoidea tienen la misma disposición de órganos del sistema digestivo durante los estadíos de desarrollo tempranos, pero se diferencian después durante el desarrollo. Es posible clasificar la forma del queratostoma superior en alguna de las dos clases reconocidas desde los estados más tempranos de desarrollo, pero la disposición de los órganos del sistema digestivo y la presencia de las proyecciones en el margen de las narinas no se puede determinar en renacuajos en sus primeras fases de desarrollo. Esto dificulta la clasificación de larvas basada en estas características morfológicas.
Uploads
Papers by David A Sanchez