Vetulicolians from the Lower Cambrian Sirius Passet Lagerstätte,North Greenland,and the polarity of morphological characters in basal deuterostomes

Abstract: Vetulicolians are problematic Cambrian fossils with a debated phylogenetic history. Here, we describe two vetulicolian specimens from the Lower Cambrian Sirius Passet locality in North Greenland. One of the specimens is assigned to Ooedigera peeli gen. et sp. nov, whereas the other is retained under open nomenclature. The mode of tail flexibility has been debated in the literature, and we argue here that the tail normally flexed laterally to generate power strokes rather than dorsoventrally. The phylogenetic relationships of vetulicolians are discussed in the light of current knowledge of deuterostome phylogeny and morphology, and it is concluded that the best hypothesis on currently available evidence is that vetulicolians are a clade or paraphyletic assemblage of stem‐Deuterostomata. The presence of a voluminous, sediment‐filled anterior chamber suggests that the atrium may be a synapomorphy of deuterostomes.     

Distribution of aquatic vascular plants in lowland rivers: separating the effects of local environmental conditions, longitudinal connectivity and river basin isolation

1. Changes in species distributions along rivers have rarely been observed independently of changes in environmental conditions and meaningful comparison between different catchments is made difficult by the limited geographical distribution of species. This study presents a new approach to quantify the effect of the spatial structure of lowland river networks on aquatic plant distribution and to explore the potential underlying processes using species life‐history characteristics. 2. Twenty‐five species of aquatic vascular plants recorded in 62 sites across five calcareous river basins were used to investigate (i) the temporal turnover of plant species, (ii) the habitat utilisation of species, (iii) the trade‐offs between different plant life‐history characteristics and (iv) the relationship between species life‐history characteristics and habitat utilisation. 3. The annual plant turnover within a 3‐year period was, although significant, extremely low. It suggests that results from spatial surveys conducted over 3 years should not be undermined by temporal changes. 4. Spatial connectivity along and between rivers was more important than in‐channel physical characteristics in shaping species assemblages. Neither chemical factors (ammonium, phosphate) nor extrinsic biotic competitors (filamentous green algae) significantly influenced plant distribution. 5. The most common combinations of life‐history characteristics were neither related to environmental conditions nor to spatial isolation. Instead, they could reflect natural selection processes associated with larger scales than those considered in this study. 6. Plant distribution was most strongly related to the dispersal and regeneration abilities of the plants, supporting the hypotheses relating to longitudinal connectivity. The hypothesis that different growth forms would be associated with different in‐channel physical features was not verified. As expected, there were no substantial differences in plant life‐history characteristics between river basins.     

Effects of creatine precursors in arthritis; clinical and metabolic study of glycocyamine and betaine

Twenty-two patients with arthritis received 5 gm. of glycocyamine and 20.16 gm. of betaine by mouth daily, in hospital and after discharge, for periods ranging from 13 to 42 days. A control group of 22 patients, indistinguishable from the treated group, were maintained on the same regimen and given placebos resembling the agents under study. The condition of each patient was evaluated clinically before, during and after treatment, and x-ray and metabolic studies were made. No significant improvement attributable to the use of the drugs was observed.     

The costs of sex in seaweeds

The brown seaweeds (Fucales) include dioecious and hermaphrodite species and genera with one, two, tour or eight eggs per oogonium. The costs of gamete production, measured as biomass, are very small. Eggs represent only 0.1–0.4% of body weight. Females of dioecious species do not produce more eggs per gramme of tissue than hermaphrodites. Hermaphrodites occupy upper shore zones and dioecious species the biotically richer submerged zones. Neither egg size nor number correlate with habitat or sexuality. Some of these observations are hard to reconcile with theoretical concepts of the costs of sex.     

Influence of intra‐tree variation in phenology and oviposition site on the distribution and performance of Ennomos subsignaria on mature sycamore maple

Abstract 1. Field surveys and a manipulative experiment were conducted to examine the hypotheses that intra‐tree heterogeneity in natural enemy activity, foliar quality (independent of phenology), or phenology influence the intra‐tree distribution and performance of Ennomos subsignaria on mature sycamore maple, Acer pseudoplatanus. 2. Ennomos subsignaria intra‐tree distribution was distinctly clumped. Egg mass density was 85% higher on the lower bole than in the crown. Most early instars were found on lower crown proximal branches while most late instars and pupae were found on lower crown distal branches. This resulted in high levels of defoliation in the lower crown, especially on proximal branches. 3. No parasitoids were reared from eggs or late‐instar larvae and only one pupa was parasitised, suggesting that preference for the bole and lower crown was not a response to parasitism. Similarly, E. subsignaria performance was not influenced by variable foliage quality (independent of phenology) within the crown. However, sycamore maple phenology had a large influence on E. subsignaria survival. More than 90% of newly emerged larvae survived to the adult stage when they fed on foliage with three pairs of leaves expanded per bud, whereas survival on younger foliage was reduced by >45%. 4. The peak period of E. subsignaria egg hatch was approximately 2 weeks after the peak period of sycamore maple budburst, which occurred acropetally. Egg hatch was closely synchronised with the availability of most suitable leaves for insect development on proximal branches of the lower crown, the location where most larvae initiated feeding. 5. The results support the phenology hypothesis and suggest that intra‐tree variation in oviposition site and host phenological development influence the intra‐tree distribution and performance of this generalist herbivore.