Effects of wetland connectivity on overwintering and movement behaviours of Australian freshwater turtles

Freshwater turtles are important consumers in Australian freshwater ecosystems. They serve as scavengers, nutrient regulators, and as food sources and Totems for Traditional Owners throughout Australia. Despite their importance, most Australian freshwater turtle species are declining. The impact of winter wetland drying on turtle populations remains unknown, and winter exposure of hibernating turtles may be an important additional source of mortality. We aimed to examine turtle responses to seasonal and episodic wetland drying in wetlands using acoustic telemetry and active trapping. Wetlands were chosen that spanned a range of hydrological connectivity to the adjacent Edward/Kolety-Wakool River. We found that tagged Emydura macquarii typically exit wetlands disconnected from the adjacent permanent river prior to winter, and overwinter in the river. Female E. macquarii rapidly re-entered ‘home’ wetlands (wetlands in which they were initially tagged) the following spring, whereas males tended to leave the study area, returning occasionally. Although we were not able to evaluate a winter drying event, one of the wetlands experienced partial summer drying. All three local turtle species (E. macquarii, Chelodina expansa, C. longicollis) exited the wetland long before winter drying would have become a potential threat. Our results suggest that turtles in this system may be protected from winter wetland drying because they move to the adjacent permanent river prior to winter. Spending the winter in the river channel reduces the risks of being trapped in a drying wetland as temperatures drop in winter.     

Reduced chemotactic peptide binding in juvenile periodontitis: a model for neutrophil function

Chemotactic peptide binding sites from peripheral blood neutrophils of Localized Juvenile Periodontitis patients and normal controls were quantitated using tritiated N-formylmethionylleucyl-phenylalanine and a rapid filtration assay. It was found that there is a significant reduction in the number of binding sites per cell on neutrophils from the patient group whereas binding affinity remained the same as control values. A direct correlation between $\text{in}\text{vitro}$ neutrophil chemotactic response and density of binding sites was found. Since these patients present little clinical illness, localized juvenile periodontitis can be a valuable model for the study of human neutrophil function.     

A fossil brain from the Cretaceous of European Russia and avian sensory evolution

Fossils preserving traces of soft anatomy are rare in the fossil record; even rarer is evidence bearing on the size and shape of sense organs that provide us with insights into mode of life. Here, we describe unique fossil preservation of an avian brain from the Volgograd region of European Russia. The brain of this Melovatka bird is similar in shape and morphology to those of known fossil ornithurines (the lineage that includes living birds), such as the marine diving birds Hesperornis and Enaliornis, but documents a new stage in avian sensory evolution: acute nocturnal vision coupled with well-developed hearing and smell, developed by the Late Cretaceous (ca 90Myr ago). This fossil also provides insights into previous 'bird-like' brain reconstructions for the most basal avian Archaeopteryx--reduction of olfactory lobes (sense of smell) and enlargement of the hindbrain (cerebellum) occurred subsequent to Archaeopteryx in avian evolution, closer to the ornithurine lineage that comprises living birds. The Melovatka bird also suggests that brain enlargement in early avians was not correlated with the evolution of powered flight.     

Ineffectiveness of plastic mesh for protecting artificial freshwater turtle nests from red fox (Vulpes vulpes) predation

Invasive mammalian predators are efficient at driving native animal declines. The red fox (Vulpes vulpes) kills millions of endemic reptiles in Australia each year. In areas of south-eastern Australia, the eastern long-necked turtle (Chelodina longicollis) and Murray River turtle (Emydura macquarii) have declined by more than 50%. High rates of nest predation by foxes limit the recruitment of young turtles in these populations, but previous methods of fox control have been ineffective at protecting turtle nests. Here, we tested the effectiveness of plastic mesh for protecting artificial turtle nests from predation by foxes, in the mid-Murray catchment, Victoria. We also tested whether protecting a large number of artificial nests in a given area encourages foxes to give up foraging following predictions from giving-up density theory. We made a series of plots, each containing 32 artificial turtle nests. In each plot, we covered a percentage (0%, 25%, 50%, 81% or 100%) of the nests with either 1 or 2 sheets of plastic mesh. We used remote cameras to photograph and identify any predator that attacked nests in the plots. The cameras also allowed us to estimate the amount of time a fox was visible on each plot, as a metric of how much effort foxes expended on protected nests. Nest survival rate was not increased by either 1 or 2 sheets of mesh, and increasing the number of protected nests on a plot did not reveal a giving-up density (GUD) value for fox foraging behaviour. Our study demonstrates that plastic mesh is not effective for protecting artificial turtle nests from foxes in this region.     

Genetic implications of mating structure in a Caribbean isolate.

Mating patterns in the population of St. Barthélémy, French West Indies, are examined to evaluate the expected genetic consequences of consanguinity avoidance and of failure to mate due to celibacy and emigration. Nearly 60% of all individuals reaching mating age on "St. Bart" never contribute to the gene pool of succeeding generations. This greatly reduces the effective population size and, therefore, increases genetic drift or random inbreeding. The consequent loss of heterozygosity is partially countered by the fact that the individuals who fail to reproduce within the population tend to be more closely related to the population than are those who do reproduce. This nonrandom failure to mate results in nonrandom inbreeding, which reduces total pedigree inbreeding. Total inbreeding is also reduced by consanguinity avoidance. However, the effect of avoiding close consanguineous matings is, to some extent, reversed by an apparent preference for more distant relationships, especially with second cousins. Generally similar results are found for the related Northside French population of St. Thomas. U.S. Virgin Islands. A recently developed mathematical model predicts the expected effect on heterozygosity of partial or complete avoidance of, or preference for, any combination of consanguineous matings, and also takes into account nonrandom failure to mate. Application of this model to these two populations suggests that under some circumstances nonrandomness in celibacy and emigration may have a greater influence on genotype distributions than does consanguinity avoidance.     

Pectoral fin morphology of batoid fishes (Chondrichthyes: Batoidea): Explaining phylogenetic variation with geometric morphometrics

The diverse cartilaginous fish lineage, Batoidea (rays, skates, and allies), sister taxon to sharks, comprises a huge range of morphological diversity which to date remains unquantified and unexplained in terms of evolution or locomotor style. A recent molecular phylogeny has enabled us to confidently assess broadscale aspects of morphology across Batoidea. Geometric morphometrics quantifies the major aspects of shape variation, focusing on the enlarged pectoral fins which characterize batoids, to explore relationships between ancestry, locomotion and habitat. A database of 253 specimens, encompassing 60 of the 72 batoid genera, reveals that the majority of morphological variation across Batoidea is attributable to fin aspect‐ratio and the chordwise location of fin apexes. Both aspect‐ratio and apex location exhibit significant phylogenetic signal. Standardized independent linear contrast analysis reveals that fin aspect‐ratio can predict locomotor style. This study provides the first evidence that low aspect‐ratio fins are correlated with undulatory‐style locomotion in batoids, whereas high aspect‐ratio fins are correlated with oscillatory locomotion. We also show that it is phylogeny that determines locomotor style. In addition, body‐ and caudal fin‐locomotors are shown to exhibit low aspect‐ratio fins, whereas a pelagic lifestyle correlates with high aspect‐ratio fins. These results emphasize the importance of phylogeny in determining batoid pectoral fin shape, however, interactions with other constraints, most notably locomotor style, are also highlighted as significant. J. Morphol. 275:1173–1186, 2014. © 2014 Wiley Periodicals, Inc.     

Exercise-training-induced alterations in hepatic function in mares

The effects of exercise training on hepaticfunction in horses were determined by studying the plasma clearance ofantipyrine (20 mg/kg iv) in adult mares that either underwent treadmilltraining for 5 wk (n = 7) or remainedin box stalls for the same time period (n = 6). Training consisted oftreadmill exercise at 60% (12 min/day) and 90% (3 min/day) ofpretraining maximal oxygen consumption (O_{2 max}) for 6 days/wk for 5 wk.O_{2 max} andvelocity to obtain a blood lactate concentration of 4 mmol/l weresignificantly increased (from 129 to 149 ml · min¹ · kg¹and from 5.6 to 6.1 m/s, respectively) as a result of training. Theplasma clearance and volume of distribution of antipyrine increasedsignificantly in the trained group (from 5.5 to 6.4 ml · min¹ · kg¹and from 813 to 881 ml/kg, respectively) and decreased significantly inthe untrained group. Elimination half-lives did not change as a resultof training or box rest. Increases in plasma antipyrine clearance wereindicative of an increase in hepatic metabolism of antipyrine.Increases in the volume of distribution of antipyrine suggest thattotal body water increases as a result of exercise training.