ABSTRACT This study estimated the population density of Spondylus limbatus at six fishing banks that are representative of the Gulf of California, Mexico. Each bank was identified in July 2011. There were significant differences in density between banks, and a steady north-to-south decrease in density that was fitted to a potential model. At low densities, S. limbatus showed a lower variability in size. Since the densities of S. limbatus are suitable for commercial exploitation, sustainable extraction can be performed under a population recovery approach. Also, this study represents a baseline for the evaluation and monitoring of populations of this species through time and contributes to set general guidelines for the assessment of commercial feasibility and exploitation criteria.

Abstract We report the first record of the Choco broad-nosed bat (Plathyrrhinus chocoensis Alberico & Velazco, 1991) in Santo Domingo de los Tsáchilas province in northwestern Ecuador. This voucher specimen represents the southernmost record of the species and expands its distribution ca. 120 km south. The animal was caught at a farm, specifically in a live fence consisting of several tree species. Preservation of bat species occurring in agricultural landscapes requires local policies and environmental education.

Introduction: some physioecological responses from rodents may be registered through the study of morphological indexes, which is an important factor for the control of rodents. Objectives: to compare the morphophysiological variables in two rat populations and relate them to the ectoparasite loads. Methods: this study was carried out from 2007 to 2008 in two sites of La Habana province. Specially prepared traps to catch rats alive were used. Four morphophysiological indexes were studied and then compared through a variance analysis for the two sites. Results: one hundred four Rattus rattus (83.6 %) and Rattus norvegicus (16.4 %) were analyzed. The relative kidney index showed highly significant different between the rat populations. The morphophysiological indexes were lower in parasitized animals. The ecological importance and the implications of these indexes for the control of obtained results were discussed in this paper. Conclusions: the morphophysiological analysis proved that the necessary resources for the survival of these species are available, which favors that both rat sexes bear the ectoparasite load in a better way, and thus they represent parasite reservoirs and a permanent transmission risk.

Introducción: algunas respuestas fisioecológicas en roedores se pueden registrar a través del estudio de los índices morfológicos, lo cual constituye un factor de importancia para el control de los múridos. Objetivos: comparar las variables morfofisiológicas en dos poblaciones de ratas y relacionarlas con la carga de ectoparásitos. Métodos: el estudio se realizó entre 2007 y 2008 en dos localidades de La Habana. Para apresar los animales se utilizaron trampas de captura viva previamente cebadas. Se estudiaron cuatro índices morfofisiológicos que fueron comparados entre las dos localidades por un análisis de varianza. Resultados: se analizó un total de 104 roedores identificados como Rattus rattus (83,6 %) y Rattus norvegicus (16,4 %). El índice de riñón relativo presentó diferencias altamente significativas entres las poblaciones. Los valores de los índices morfofisiológicos resultaron inferiores en los animales parasitados. La importancia ecológica y su implicación para el control de los resultados obtenidos son discutidas en el trabajo. Conclusiones: el análisis morfofisiológico demostró que en el puerto de La Habana existe disponibilidad de recursos necesarios para la supervivencia de estas especies, lo cual favorece que los dos sexos soporten mejor la carga de ectoparásitos y constituyan reservorios de estos, así como riesgo de transmisión permanente.

This is a first record of Probstmayria tapiri in Mexico, was found in 60 (41.09%) fecal samples from Baird's tapir (Tapirus bairdii) in the Biosphera Reserves "La Sepultura" and "El Triunfo" in the Sierra Madre de Chiapas, Mexico. Morphological characteristics of small nematode spindle-shaped forms truncated anteriorly and with a long, gradually attenuated, acutely pointed tail. Mouth with tree lips, pharynx elongated, aesophagus with tree portions: Anterior portion, long and slender, posterior portion, shorter, and pyriform portion, with a bulb. The excretory pore is situated near oesophagi bulb and ventral surface of the body. Vulva of female at about the middle of the body. Spicules assymetrical and curved. On the ventral surface of the tail there are nine small postanal papillae. These results allow us to extend their geographic distribution of nematode to Central America and another species of Tapir's (T. bairdii). Finally we emphasized that the environmental conditions of La Sierra Madre de Chiapas, are optimal for the biological development of this nematode from tapirs of Central and South America.

Primer registro de Probstmayria tapiri en México y para la especie de Tapirus bairdii (tapir Centroamericano), en la que se hace una redescripción de este nematodo. Se encontró en 60 (41.09%) muestras de excretas frescas recolectadas en las Reservas de la Biosfera "La Sepultura" y "El Triunfo" en la Sierra Madre de Chiapas, México. Las características morfológicas de los especimenes observados son nematodos pequeños con cutícula finamente estriada, fusiforme que gradualmente disminuye su diámetro hacia ambos extremos, terminando en una cola aguda. Boca hexagonal con tres labios bilobulados, faringe alargada, esófago con tres porciones: anterior, larga y delgada, media, corta y estrecha, piriforme, con un bulbo. El poro excretor se encuentra situado cerca del bulbo esofágico y ventral a la superficie del cuerpo. La vulva de la hembra esta cerca de la porción media del cuerpo. Las espículas del macho son asimétricas y curvadas. En la superficie ventral de la cola hay nueve papilas postanales. Estos resultados nos permiten ampliar la distribución geográfica del nematodo a Centroamérica y otra especie de tapir (T. bairdii). Finalmente enfatizamos que las condiciones ambientales de la Sierra Madre son óptimas para el desarrollo biológico de este nematodo de los miembros de la Familia Tapiridae en Centroamérica y Sudamérica.