Alberto Veloso

Phylogenetic relationships of Chilean leptodactylids: a molecular approach based on mitochondrial genes 12S and 16S

La mayoria de los anfibios chilenos pertenece a la subfamilia Telmatobiinae (Anura, Leptodactylidae). Varios estudios filogeneticos de Leptodactylidae y Telmatobiinae, basados principalmente en caracteres morfologicos, han sugerido implicitamente relaciones mas estrechas de algunas especies de Telmatobiinae con miembros de otras subfamilias de leptodactilidos, incluyendo el genero leptodactilino Pleurodema presente en Chile. Ademas, un numero creciente de estudios moleculares sugieren un estatus no monofiletico para Telmatobiinae, aunque ninguno de estos estudios ha investigado las relaciones filogeneticas de esta subfamilia. Secuencias parciales de los genes ribosomales mitocondriales 12S y 16S fueron comparadas para determinar las relaciones filogeneticas de los leptodactilidos chilenos y su posicion dentro de los anuros modernos (Neobatrachia). Se incluyeron 22 especies de nueve de los diez generos de telmatobinos presentes en Chile (Alsodes, Atelognathus, Batrachyla, Caudiverbera, Eupsophus, Hylorina, Insuetophrynus, Telmatobufo y Telmatobius), dos especies del genero Pleurodema y una especie de Rhinodermatidae la cual es considerada una familia derivada de los leptodactilidos por algunos autores. Se incluyeron ademas 51 especies que representan la mayoria de las familias que componen Neobatrachia. Las reconstrucciones filogeneticas se realizaron utilizando los metodos de maxima parsimonia, maxima verosimilitud e inferencia bayesiana. Las topologias obtenidas en todos los analisis indican que Telmatobiinae es un ensamblaje polifiletico, compuesto por especies que pertenecen a Hyloidea (la mayoria de los generos) y especies mas relacionadas con taxa de Australasia (el clado Caudiverbera + Telmatobufo, definido como la tribu Calyptocephalellini). Estos datos moleculares respaldan agrupaciones basadas en otro tipo de evidencia (Caudiverbera + Telmatobufo, Alsodes + Eupsophus y Batrachyla + Hylorina) y plantean nuevas hipotesis de relaciones para algunos generos de telmatobinos (Atelognathus con Batrachyla e Hylorina, Insuetophrynus + Rhinoderma). Las relaciones filogeneticas observadas en este estudio sugieren un origen multiple para los anuros del bosque templado de Chile y revelan un inesperado nivel de diversidad taxonomica y divergencia evolutiva entre los leptodactilidos chilenos

Altitudinal distribution and blood values in the toad, Bufo spinulosus Wiegmann.

1. Red blood cell (RBC) count, RBC size, hematocrit, cell and blood hemoglobin concentrations and plasma total solid concentration were measured in 16 lowland (from near sea level up to 2700 m) and 18 highland (3200 up to close to 4500 m) adult toads (Bufo spinulosus). 2. Lowland toads showed higher hematocrit values than highland toads, but their blood hemoglobin concentration and plasma solid concentration were not significantly different. 3. Highland toads had smaller RBC size, higher corpuscular hemoglobin concentration, a trend toward larger RBC count and a considerably smaller body size. These features may contribute to their successful life at high altitude.

Respiratory and hematological adaptations to high altitude in Telmatobius frogs from the chilean andes

Abstract 1. 1. Cutaneous and pulmonary oxygen uptake has been determined in the Andean frog T. marmoratus, collected above 4300 m, and hematological values measured in this and three other Telmatobius species from high altitude. 2. 2. At different temperatures cutaneous respiration was consistently higher than pulmonary O2 consumption. 3. 3. At 10°C citical pO2 was 94 torr, similar to the pO2 levels found in the highest stream sites. 4. 4. All four Telmatobius species had a large number of very small RBCs. 5. 5. The MCV in T. pefauri may be considered as the smallest reported for amphibians, while the MCHC in T. peruvianus is the highest known in this class.

Physiological factors affecting triploid production in rainbow trout, Oncorhynchus mykiss

The influence of three physiological factors related to triploid production was examined for rainbow trout. Individual spawnings of 46 females were used to perform triploid production experiments from 1989 to 1991, with various water temperatures (6–13.8°C) at stripping and egg incubation. The percentage of triploids was similar for a heat shock of 26.5°C for 15 min applied 15 or 25 min after fertilization (73.4±5.6% vs 78.6±4.5%). A tendency to a higher percentage of triploids (85.9±5.7%) was observed for water temperatures of 6–8.0°C at stripping and incubation, compared to at higher water temperatures of 12.1–14°C (63.0±8.4%). Analysis of variance indicated an effect of four categories of water temperature (6–8, 8.1–10, 10.1–12, 12.1–14°C) on triploid product at P = 0.14. Regression analysis confirmed these as significant (r = −0.36; P < 0.02). A significant increase in percentage of triploids was observed when eggs remained 2, 6 and 10 days in the body cavity. The mean % triploidy was 46.1, 54.7 and 76.8, respectively. Similar results were observed for survival of the eggs.

Biogeography of Chilean herpetofauna: distributional patterns of species richness and endemism

We analyze the geographic distribution pattern of Chilean amphibian and reptile species between 18°20′S (Arica) to 56°S (Magellanic Area) by the identification of centers of higher richness and endemism and we infer the biological processes that could have promoted these patterns from a biogeographic point of view, comparing our results with the present location of National Parks found in the National System of State Wildlife Protected Areas. Our results provide evidence that richness and endemism shows clear latitudinal trends along Chile, with highest values at mid-latitudes (31°S to 44°S). Five areas of endemism for phenetic analysis and six for PAE (Parsimony analysis of endemism) were found that agree with bioclimatic boundaries. We suggest that the richness and endemism patterns registered for Chilean herpetological taxa may be explained by an historical mechanism, in accordance with previous biogeographical proposals. To improve the conservation efforts for amphibians and reptiles we suggest inclusion of new protected areas at the regional level for the Mediterranean region of south-central Chile and for local northern and southern quadrats with high species richness and endemism.

Insular morphological divergence in the lizard Liolaemus pictus (Liolaemidae)

Liolaemus pictus is a widely distributed arboreal lizard species in southern Chile. Within this species, mainland and island subspecies have been described mainly based on external morphological characters, however, their diagnostic characters have not been accurately demarcated. We used both traditional and geometric morphometrics to study the morphological divergence in L. pictus subspecies. Since geographic isolation can be related to environmental variation (e.g., variation in abundance and richness of insects or fruits), we predict that the L. pictus morphology could vary in head shape between mainland and island localities.Our results show morphological divergence in all variables analyzed among the island and mainland localities. The traditional morphometric approach reveals differences between populations from the mainland and island localities, where the mainland populations show a larger head size. Geometric morphometric data indicate that the eye orbits of the island specimens are more extended than in the mainland specimens in the dorsal view; this is probably related to a different capacity of substrate used. Also, in the lateral view, the eye orbits are extended and the head shape is less dorso-ventrally compressed in the island locality than in mainland populations and the terminal mouth position is more posterior in island specimens. We suggest that the morphological variation between mainland and island localities could be related to the fact that these populations were isolated during the last maximum glacial period in southern Chile, a period in which geomorphologic and bioclimatic features of this area were modified forming the present archipelago.

The Population Decline and Extinction of Darwin's Frogs

Darwin’s frogs (Rhinoderma darwinii and R. rufum) are two species of mouth-brooding frogs from Chile and Argentina. Here, we present evidence on the extent of declines, current distribution and conservation status of Rhinoderma spp.; including information on abundance, habitat and threats to extant Darwin’s frog populations. All known archived Rhinoderma specimens were examined in museums in North America, Europe and South America. Extensive surveys were carried out throughout the historical ranges of R. rufum and R. darwinii from 2008 to 2012. Literature review and location data of 2,244 archived specimens were used to develop historical distribution maps for Rhinoderma spp. Based on records of sightings, optimal linear estimation was used to estimate whether R. rufum can be considered extinct. No extant R. rufum was found and our modelling inferred that this species became extinct in 1982 (95% CI, 1980–2000). Rhinoderma darwinii was found in 36 sites. All populations were within native forest and abundance was highest in Chiloé Island, when compared with Coast, Andes and South populations. Estimated population size and density (five populations) averaged 33.2 frogs/population (range, 10.2–56.3) and 14.9 frogs/100 m2 (range, 5.3–74.1), respectively. Our results provide further evidence that R. rufum is extinct and indicate that R. darwinii has declined to a much greater degree than previously recognised. Although this species can still be found across a large part of its historical range, remaining populations are small and severely fragmented. Conservation efforts for R. darwinii should be stepped up and the species re-classified as Endangered.

Phylogeography of Rhinella spinulosa (Anura: Bufonidae) in northern Chile

The southern part of the Altiplano of the Andes Range is characterized by a complex hydrography, due to an intense geologic activity and the effects of the Pleistocene glaciations. This has produced a high degree of diversity at the species level in some aquatic taxa (e.g., fish and amphibians), which suggests that these same processes have produced divergence at the intraspecific level in co-distributed taxa. We investigated the genetic variation in populations of the anuran Rhinella spinulosa which represent its entire distribution in the extreme north of Chile (17°44′S-23°47′S). Haplotype networks of the mitochondrial control region recognized two main lineages, one of which is distributed from the northern boundary of Chile to the Salar de Alconcha and the other from the Salar de Carcote to the locality of Tilomonte. The northern lineage showed little phylogeographic structure; a few very frequent haplotypes are widely distributed. The southern lineage had greater structure, due principally to the high divergence of the populations from the eastern springs of the Salar de Atacama. Fus Fs test and the mismatch distributions suggested that most of the populations of both lineages are in the process of demographic expansion. The spatial distribution of the genetic variability was correlated with the hydrography and the paleoclimatological data available for the region, which suggested that geographic expansions followed by periods of contraction of population ranges, together with sporadic floods may explain the observed phylogeographic patterns.

Assimilation efficiency in Bufo spinulosus tadpoles (Anura: Bufonidae): effects of temperature, diet quality and geographic origin

La eficiencia de asimilacion de materia en larvas de Bufo spinulosus provenientes de cuatro localidades de Chile, fue evaluada para dos temperaturas (15 y 25 oC) y dos dietas diferentes (pobre: 22,28 mg g N-1 y rica 47,53 mg g N-1), utilizando la ceniza como marcador de digestion. Los resultados mostraron que la localidad de origen de las larvas no afecta la eficiencia de asimilacion, mientras que se registro una interaccion significativa entre la temperatura y la calidad de la dieta. La eficiencia de asimilacion es mayor para la dieta rica cuando las larvas fueron mantenidas a 15 °C, no existiendo diferencias entre dietas cuando fueron mantenidas a 25 °C. Nuestros resultados sugieren que para B. spinulosus el efecto de la temperatura sobre los procesos digestivos es mas relevante que su efecto sobre el tiempo de transito en el tracto digestivo. Las diferencias en el tamano alcanzado a la metamorfosis en poblaciones de B. spinulosus de origen geografico distinto, no podrian ser explicadas por la existencia de diferencias en las capacidades fisiologicas digestivas

Chromosome Location of Active Ribosomal Genes in Pleurodema Thaul (Amphibia-Leptodactylidae). C-Banding and Polymorphism of The Nucleolar Organizer Region

SUMMARYSpecimens of Pleurodema thaul collected in three localities from central Chile (32–33 SL), were studied. Patterns of C-heterochromatin distribution, localization and activity of Nucleolar Organizer Regions (NORs) were established using the silver banding technique and the fluorochrome quinacrine mustard. It was show that specimens from all localities have the same pattern of C-bands. In all except three specimens from one population there are only two NORs on chromosome pair number 8 in correspondence with two secondary constrictions present in Giemsa or quinacrine mustard stained chromosomes. In this three specimens, there is a supplementary secondary constriction in pair number 3, where there are active DNAr genes as is revealed by the silver chromosome stain and the number of nucleoli found in the interphase nuclei. Most specimens have differences in NORs length when carrier chromosomes are compared. However, there are no differences in nucleolar sizes in their interphase nuclei. The significanc...