Mariana Fiuza de Castro Loguercio

Mammals of Serra da Bocaina National Park, state of Rio de Janeiro, southeastern Brazil

Here we present a commented list of mammals registered in the Serra da Bocaina National Park. Three field trips (February, 2010, and May and July, 2011) were accomplished along the RJ-165 highway in the Municipality of Paraty, State of Rio de Janeiro, Brazil. Forty-eight species belonging to nine orders were recorded. The local mammal fauna could be considered diverse and rich, with some species regarded as biological indicators of habitat quality. Endangered and rare rodent species like Blarinomys breviceps , Juliomys rimofrons , and Thaptomys nigrita were captured. Road and hunting impacts on mammals are discussed.

Limb joints kinematics and their relation to increasing speed in the guinea pig Cavia porcellus (Mammalia: Rodentia)

The kinematics of each joint of the guinea pig Cavia porcellus were studied during the locomotor cycle at increasing speed by high-speed cinefluorography. The main objective was to reveal the functional specific features of these structural elements in each dynamic phase of the cycle and also which limb joints are important during the increase of animal speed. Most of the analysed angles in C. porcellus were affected as the speed increased, both in trot and gallop. However, only a few of them were correlated with speed. There were also differences with respect to symmetrical or asymmetrical gaits. Both pairs of limbs responded differently to the increase of speed; while the forelimb joints modified the duration of their action (frequency) more than the amplitude (stride length), the hindlimbs acted inversely. The movements of the joints during the stance phase changed dramatically with speed, particularly in the hindlimb. At knee level, the flexion amplitude increases to maintain the stiffness of the leg spring, a principle previously discussed as essential for the running process. In the swing phase, inertial effects are the main constraints and, as in the stance phase, the knee joint in the swing phase is correlated with speed both during trot and gallop, confirming the major importance of this joint to increasing speed.

Locomotion in Aquatic, Terrestrial, and Arboreal Habitat of Thick-Tailed Opossum, Lutreolina crassicaudata (Desmarest, 1804)

Abstract The reasons Lutreolina crassicaudata is always captured in close proximity to water are not clear. We investigated locomotory behavior and performance in swimming, running, climbing, and jumping of L. crassicaudata. One adult male was videotaped in the laboratory while swimming, walking on the ground and on a horizontal tube 1.2 m from the ground, climbing a tree trunk angled 45°, and jumping gaps between supports. The locomotor cycles in these different activities were described by speed, stride length, stroke or stride frequency, time of power and recovery phases or stance and swing phases, and by displacement of points on the animal. L. crassicaudata employed a quadruped paddling gait in swimming. Swimming speed was similar to that of terrestrial didelphids, but stroke frequency and buoyancy ability were more similar to those of the water opossum. Different gaits were used for locomotion in each habitat type and we conclude that L. crassicaudata cannot be considered a specialized species for aquatic locomotion.

Growth, Shedding and Food Intake in Captive Eunectes murinus (Linnaeus, 1758) (Serpentes: Boidae)

La anaconda Eunectes murinus (Linnaeus, 1758) se encuentra en una ampia area hidrografica de America tropical y figura entre las mas grandes serpientes del mundo, alcanzando una longitud de 12 metros. Este estudio analizo el crecimiento de tres anacondas hembras hermanas, con registros de su nacimiento en cautiverio hasta alrededor de 14 meses de edad. Las serpientes fueron mantenidas en un medio controlado con temperatura constante y se obtuvieron registros relacionados con su biometria, alimentacion y mudas de piel. Al final de 445 dias, las hermanas crecieron en promedio 2,6 veces su longitud inicial e incrementaron su peso inicial en 3810,1 g, incorporando a su masa corporal alrededor de 43,5% del alimento ingerido. Ellas tuvieron un total de 0,69 mudas de piel por mes en ese periodo y no hubo diferencias significativas en los intervalos de mudas, ni en el crecimiento corporal (peso y longitud), cuando comparadas entre ellas. La comida, a veces, fue rechazada coincidiendo con los dias que precedian al cambio de piel. Las mudas de piel parecen no tener relacion con la alimentacion o crecimiento, lo cual sugiere que puede deberse a otros factores endogenos. Es necesario un estudio mas detallado de esta especie para comprender mejor su crecimiento en la fase adulta y sus niveles hormonales durante el crecimiento

Topographical Anatomy of the Blunthead Treesnake, Imantodes cenchoa (Linnaeus, 1758) (Colubridae: Xenodontinae)

Imantodes cenchoa (Dumeril, 1853) es una serpiente xenodontinea, arborea, noctura y ovipara, que se alimenta de anfibios y largartos. Se encuenta en America Central y del Sur, incluyendo las partes Norte y Central de Brasil. En este trabajo, investigamos la relaciones entre la Anatomia Topografica y habitat en I. cenchoa. Fueron examinados 20 especimenes (13 hembras no prenadas y 7 machos). El estudio de la Anatomia Topografica fue realizada a traves de observaciones de la anatomia interna, particularmente la posicion y tamano del pulmon, corazon, higado, gonadas y rinones derechos e izquierdos. Los resultados mostraron que todos los organos estan localizados en una posicion posterior, en relacion a la entrada de la longitud del hocico(SVL). El centro de gravedad se encuentra a 74% de SVL en machos y hembras. En los machos, no fue observada alometria positiva entre la posicion de los organos. Fue observada alometria negativa en las hembras, considerando la posicion del extremo anterior del rinon izquierdo, los extremos anterior y posterior del rinon derecho y ambos ovarios. En machos, se presento alometria negativa en la posicion de todos los organos. La distancia entre el ultimo foliculo y la cloaca fue 8.78% de SVL. Nuestros datos corroboran la idea que la posicion posterior de todos los organos internos esta marcada por una especializacion al habitat de una serpiente, marcando la especie arborea I. cenchoa con una especial topografia interna posterior

Body and skull morphometric variations between two shovel-headed species of Amphisbaenia (Reptilia: Squamata) with morphofunctional inferences on burrowing

Background Morphological descriptions comparing Leposternon microcephalum and L. scutigerum have been made previously. However, these taxa lack a formal quantitative morphological characterization, and comparative studies suggest that morphology and burrowing performance are be related. The excavatory movements of L. microcephalum have been described in detail. However, there is a lack of studies comparing locomotor patterns and/or performance among different amphisbaenids sharing the same skull shape. This paper presents the first study of comparative morphometric variations between two closely related amphisbaenid species, L. microcephalum and L. scutigerum, with functional inferences on fossorial locomotion efficiency. Methods Inter-specific morphometric variations were verified through statistical analyses of body and cranial measures of L. microcephalum and L. scutigerum specimens. Their burrowing activity was assessed through X-ray videofluoroscopy and then compared. The influence of morphological variation on the speed of digging was tested among Leposternon individuals. Results Leposternon microcephalum and L. scutigerum are morphometrically distinct species. The first is shorter and robust with a wider head while the other is more elongated and slim with a narrower head. They share the same excavatory movements. The animals analyzed reached relatively high speeds, but individuals with narrower skulls dug faster. A negative correlation between the speed and the width of skull was determined, but not with total length or diameter of the body. Discussion The morphometric differences between L. microcephalum and L. scutigerum are in accord with morphological variations previously described. Since these species performed the same excavation pattern, we may infer that closely related amphisbaenids with the same skull type would exhibit the same excavatory pattern. The negative correlation between head width and excavation speed is also observed in others fossorial squamates. The robustness of the skull is also related to compression force in L. microcephalum. Individuals with wider heads are stronger. Thus, we suggest trade-offs between excavation speed and compression force during burrowing in this species.