Ticks (Acari: Ixodidae) associated with small terrestrial mammals in the state of Minas Gerais, southeastern Brazil

From June 2005 to November 2010, 43 small mammals encompassing 6 species of Didelphimorphia, 8 species of Rodentia, and 1 species of Lagomorpha were found parasitized by ticks in the state of Minas Gerais, southeastern Brazil. Nine tick species, in total 186 specimens, were identified as follows: Amblyomma cajennense (larvae and nymphs) on opossums and rodents; Amblyomma ovale (nymphs) on rodents; Amblyomma parvum (nymphs) on rodents; Amblyomma coelebs (nymphs) on opossums; Amblyomma dubitatum (nymph) on opossums; Ixodes amarali (females, nymphs, and larvae) on opossums and rodents; Ixodes loricatus (male, females, nymph) on opossums; Ixodes schulzei (female) on rodents; and Haemaphysalis leporispalustris (female) on rabbits. Most of the tick-host associations found in the present study have never been recorded in the literature; those include three new host records for I. amarali, four for A. cajennense, one for A. dubitatum, two for A. ovale, and one for A. coelebs. In addition, we provide the first record of A. coelebs in the state of Minas Gerais.

Phylogeographic Structure and Karyotypic Diversity of the Brazilian Shrew Mouse (Blarinomys breviceps, Sigmodontinae) in the Atlantic Forest

Blarinomys breviceps possesses cryptic and burrowing habits with poorly documented genetics and life history traits. Due to its rarity, only a few specimens and DNA sequences have been deposited in collections worldwide. Here, we present the most comprehensive cytogenetic and molecular characterization of this rare genus. Phylogenetic analyses based on partial cytochrome b sequences were performed, attempting to establish the relationships among individuals with distinct karyotypes along the geographic distribution of the genus in the Atlantic Forest. Classical and molecular cytogenetics, using banding patterns and FISH of telomeric and whole chromosome X-specific painting probes (obtained from the Akodontini Akodon cursor) were used to characterize and compare the chromosomal complements. Molecular phylogenetic analyses recovered 2 main geographically structured clades, northeastern and southeastern with pair-wise sequence divergences among specimens varying between 4.9 and 8.4%. Eight distinct karyomorphs are described: (A) 2n = 52 (50A, XX), (B) 2n = 52 (48A, XY+2Bs), (C) 2n = 45 (42A, XY+1B), (D) 2n = 43 (37A, XX+4Bs), (E) 2n = 37 (34A, XY+1B), (F) 2n = 34 (32A, XX), (G) 2n = 31 (27A, XX+2Bs), (H) 2n = 28 (26A, XY), all with the same number of autosomal arms (FNA = 50). Variation of 0-4 supernumerary chromosomes (Bs) presenting heterogeneity in morphology and distribution of interstitial telomeric sequences (ITSs) is reported. ITSs are also found in some metacentric autosomes. The phylogeographic separation between 2 major lineages with high levels of genetic divergence, and the wide karyotypic diversity indicate that B. breviceps is a diverse group that warrants taxonomic re-evaluation. Copyright (C) 2012 S. Karger AG, Basel

Field and Laboratory Studies Provide Insights into the Meaning of Day-Time Activity in a Subterranean Rodent (Ctenomys aff. knighti), the Tuco-Tuco

South American subterranean rodents (Ctenomys aff. knighti), commonly known as tuco-tucos, display nocturnal, wheel-running behavior under light-dark (LD) conditions, and free-running periods >24 h in constant darkness (DD). However, several reports in the field suggested that a substantial amount of activity occurs during daylight hours, leading us to question whether circadian entrainment in the laboratory accurately reflects behavior in natural conditions. We compared circadian patterns of locomotor activity in DD of animals previously entrained to full laboratory LD cycles (LD12:12) with those of animals that were trapped directly from the field. In both cases, activity onsets in DD immediately reflected the previous dark onset or sundown. Furthermore, freerunning periods upon release into DD were close to 24 h indicating aftereffects of prior entrainment, similarly in both conditions. No difference was detected in the phase of activity measured with and without access to a running wheel. However, when individuals were observed continuously during daylight hours in a semi-natural enclosure, they emerged above-ground on a daily basis. These day-time activities consisted of foraging and burrow maintenance, suggesting that the designation of this species as nocturnal might be inaccurate in the field. Our study of a solitary subterranean species suggests that the circadian clock is entrained similarly under field and laboratory conditions and that day-time activity expressed only in the field is required for foraging and may not be time-dictated by the circadian pacemaker.

Development of spermatogenesis in captive-bred Spix's yellow-toothed cavy (Galea spixii)

The aim of this study was to evaluate the phases of sexual development and spermatogenesis of Spix's yellow-toothed cavy (Galea spixii) based on analyses of the structural components of the testes. The testes of animals from 0 to 150 days of age were collected by orchiectomy, weighed, and processed for analysis by light microscopy. At 45 days of age, spermatozoa were seen in the tubular lumen. Spermatogenesis was not established in animals from 45 to 150 days of age. The stages of sexual development may be classified into the following phases: from birth to the age of 15 days (immature); 30 days of age (prepubertal); 45-105 days of age (pubertal); and 120 and 150 days of age (postpubertal). This is the first study to address the male reproductive biology of Spix's yellow-toothed cavy.

Activity, movement and secretive behavior of a threatened arboreal folivore, the thin-spined porcupine, in the Atlantic forest of southern Bahia, Brazil

Activity and behavior patterns are important components of a given species ecological strategy, as they have profound implications for its survival and reproduction. Here, we studied the activities, movements and secretive behavior of the thin-spined porcupine Chaetomys subspinosus (Rodentia: Erethizontidae), a threatened arboreal folivore in the Brazilian Atlantic rainforest. We aimed to ascertain the behavioral strategies used by this species as well as its responses to seasonal and daily climatic changes. Four radio-collared individuals were followed continuously for 72-h in the summer and winter, as well as during 146 half-night sessions conducted from April 2005 to September 2006 in forest remnants in southern Bahia. The thin-spined porcupines were nocturnally active (17:30-05:40 h), with peaks in activity and movement from 19:00 to 20:00 h and 03:00 to 04:00 h. Animals followed a circadian rhythm of activity during both the summer and winter. During the diel cycle, porcupines spent 74% of their time resting, 14% feeding, 11% traveling and 2% performing other activities. Distance traveled during the diel cycle averaged 277.5 +/- 117.9 m sd. The mean movement rate during the night was 21.6 +/- 30.1 m/h sd. No significant changes in activity budget or daily distance traveled were observed between seasons, most likely in response to the low fluctuations in climatic conditions and food availability throughout the year in the study region. However, rainfall reduced the time that the animals spent on feeding activities and explained day-to-day differences in activity budgets. We also provide details about intraspecific interactions and defecation behavior. Our observations confirmed that thin-spined porcupines, similar to other folivorous species, present low activity levels and short daily movements, and have adopted various cryptic habits, such as nocturnality, a solitary lifestyle, the tendency to leave offspring alone most of the time and defecation in concealed latrines.

Chimäre Archonta?: vergleichend-morphologische Studien zur Hyolaryngealregion

Chimäre Archonta? Vergleichend-morphologische Studien zur Hyolaryngealregion. Mit Brevia zur Dental- und Tarsalmorphologie. Die Dissertation greift aus phylogenetisch-systematischer Perspektive das Problem des Primatenursprungs auf. Traditionell wurde die Überordnung Archonta (= Primates + Scandentia + Dermoptera + Chiroptera) angenommen, die aufgrund molekularer Befunde nicht mehr als valide eingestuft wird. Eine Klassifikation anhand der Superordo Euarchontoglires (= Primates + Scandentia + Dermoptera + Glires) wird derzeit bevorzugt. Beide Verwandtschaftshypothesen werden in den taxonomischen Analysen berücksichtigt, um den potentiellen Einfluss der Außengruppenwahl auf die Konstellation der Euarchonta (= Primates + Dermoptera + Scandentia) zu bestimmen. Der Schwerpunkt der Untersuchung liegt in der 3D-Rekonstruktion ontogenetischer Stadien der Hyolaryngealregion diverser Spezies der Ordnungen Artiodactyla, Chiroptera, Dermoptera, Primates, Rodentia, Scandentia und Soricomorpha. Mit AMIRA® 3.1.1 konnten basierend auf histologischen Schnittserien 18 dreidimensionale Modelle der überwiegend spätfetalen Zungenbein- und Kehlkopfregion dargestellt werden. Durch das Studium der Knorpelmorphologie und der Larynx-Myologie wurden 150 Merkmale definiert und in eine MacClade®-Datenmatrix überführt. Die auf dem Parsimonie-Prinzip basierenden PAUP®-Analysen sprechen für eine Schwestergruppenbeziehung der Primates und der Dermoptera (= Primatomorpha). Die als Chimäre titulierte Überordnung Archonta wurde als Vehikel verwendet, um die Integration der Chiropteren zu ermöglichen und die Hyolaryngealforschung zu intensivieren, da auch Echolot-Peilung verwendende Taxa Bestandteil der Untersuchung waren. Die morphologischen Ähnlichkeiten des Zungenbein- und Kehlkopfapparates zwischen der basalen Form Rousettus (Pteropodidae) und dem Dermoptera-Vertreter Cynocephalus wurden als symplesiomorphe Merkmale gedeutet. Bei der Außengruppenwahl eines Rodentia-Repräsentanten hingegen konnte in Übereinstimmung mit den molekularen Befunden und nach dem Gros der Lehrmeinung die Schwestergruppenbeziehung der Primates und der Sundatheria bestätigt werden. Zwecks eines umfassenderen Ansatzes wurden im Rahmen einer „total evidence“-Methodik dental- und tarsalmorphologische Merkmale integriert. Das Resultat der Clusteranalyse, basierend auf 263 Merkmalen, modifiziert das Zwischenergebnis und befürwortet in Übereinstimmung mit molekularen Daten als Schwestergruppe der Primaten das Taxon Sundatheria (= Dermoptera + Scandentia). Damit konnte erstmals mittels eines konsequenten phylogenetisch-systematischen Ansatzes der Primaten-Grundplan hinsichtlich der Merkmalsausstattung der Hyolaryngealregion mit 27 Merkmalen rekonstruiert werden. Der Primatenursprung kann mit dem Euarchonta-Grundplan rekonstruiert werden. Für die Sundatheria wurden 12 Grundplanmerkmale definiert