The cranial anatomy and relationships of Secodontosaurus, an unusual mammal-like reptile (Synapsida: Sphenacodontidae) from the early Permian of Texas

The cranial anatomy of the Early Permian sphenacodontid synapsid Secodontosaurus is redescribed. There is no evidence for recognition of more than one species of Secodontosaurus, and S. willistoni is declared a junior subjective synonym of S. obtusidens. Numerous derived characters (autapomorphies), mainly related to the unusually slender and slightly elongated skull, distinguish Secodontosaurus. The cranial specializations are interpreted as an adaptation toward a feeding strategy which involved preying upon small tetrapods that attempted to avoid capture by hiding in crevices and burrows. A cladistic analysis supports the following hypotheses of relationships: (a) the Sphenacodontidae is the nearest sister taxon of Therapsida; (b) Secodontosaurus, Sphenacodon, Ctenospondylus and Dimetrodon share a more recent common ancestor with one another than any of them do with Haptodus, and (c) Secodontosaurus shares a more recent common ancestor with Dimetrodon than with either Sphenacodon or Ctenospondylus. The latter hypothesis suggests that the sphenacodont subfamily 'Sphenacodontinae' is paraphyletic and, therefore, invalid.     

Nitrate Assimilation and Growth of Steptoe Barley and one of its Nitrate Reductase Deficient Mutants

Barley (Hordeum vulgare L. cv. Steptoe) and a nitrate reductasedeficient mutant (narla) were grown in a nutrient film systemwith three concentrations of nitrate. Comparisons were madewith respect to growth, yield, activities of enzymes of nitrateassimilation and accumulation of nitrate and total nitrogen.In nutrient film, grain yeild of the wild-type was greater thanthat of narla. for any treatment. Nitrate reductase activitiesof narla, measured in vivo, were higher than might be expectedin an NR-deficient mutant both in leaves and especially in roots.In all treatments, narla accumulated more nitrate than did thewild-type. No significant genotypic differences were observedin nitrite reductase or glutamine synthetase activities. Whenthe two genotypes were grown in soil (i.e. when availabilityof nitrate to the roots was less than in nutrient film) differencesin growth were insignificant. Hordeum vulgare L., mutant, nitrate status, assimilation and accumulation, growth, yield     

Assessing the Helicopter and Net Gun as a Capture Technique for White-Tailed Deer

Abstract The helicopter and net gun is a technique used to capture white-tailed deer (Odocoileus virginianus) and is useful in a variety of habitat types and at various population densities with the ability to be highly selective. During capture, deer may sustain injuries or even die as a result of capture and handling, and may also be prone to capture myopathy. Therefore, our objectives were to determine 1) type and frequency of injuries sustained during the helicopter and net-gun capture, and 2) the effects of capture on survival of radiocollared deer. We captured 3,350 white-tailed deer from 1998 to 2005 using a net gun fired from a helicopter on 5 southern Texas, USA, ranches. Additionally, we captured 51 yearling males and 49 mature (≥4 yr of age) males and fitted them with radiocollars to monitor their survival. We recorded injuries and mortalities during capture and ranked the seriousness of injuries on a scale from 0 to 4. We recorded 281 injuries (8.4%) and as a result of capture, at least 206 deer had broken antlers (6.1%), 55 were injured (1.6%), and 20 were direct mortalities (0.6%). The most common antler injury was broken antler tines and the most common body injury was broken legs. Postcapture mortality rates were low (1%) for this capture method. Based on capture-related injuries, mortalities, and postcapture survival, we found the helicopter and net gun to be a safe capture technique compared to other capture techniques, particularly when conditions are favorable.     

Parental role division predicts avian preen wax cycles

Previous studies have shown that preen wax composition in some sandpipers shifts from the usual monoesters to diesters during the breeding season, possibly to reduce the ability of mammalian predators to find nests using olfactory cues. To investigate further the relationship between incubation and wax secretion, we examined seven sandpiper species with different incubation patterns (species in which both sexes incubate, in which only males incubate and in which only females incubate). During the breeding period, diester preen wax was secreted almost exclusively by the incubating sex in species with uniparental incubation, and by both sexes in species with biparental incubation. These findings suggest that diester preen waxes have a function that is directly related to incubation. Unexpectedly, in female-incubating Curlew Sandpiper Calidris ferruginea and Buff-breasted Sandpiper Tryngites subruficollis , some males also secreted diester preen waxes during the breeding period. This suggests that some males may in fact incubate, that these waxes may be a remnant from their evolutionary past when both sexes incubated, or that males need to be olfactorally cryptic because they are involved in the making of nest scrapes. The seasonal pattern of preen wax composition was also studied in captive male, female and female-mimicking male ('faeder') Ruff Philomachus pugnax . Captive female Ruff changed preen wax composition from monoesters to diesters in the spring despite the fact that no incubation took place. This suggests that circannual rhythms rather than actual incubation behaviour may trigger the shift to diester waxes. All captive male Ruff, including the faeders, continued to secrete monoesters, supporting the hypothesis that only the incubating sex secretes diesters.