FOSSIL OONOPID SPIDERS IN CRETACEOUS AMBERS FROM CANADA AND MYANMAR

Abstract:  The spider family Oonopidae is described from Cretaceous ambers from Myanmar and Canada for the first time. Orchestina albertenis sp. nov. is the first spider to be described from Canadian Grassy Lake amber and only the second spider to be described from Canadian amber. The specimen in amber from Myanmar extends the known range of the extant genus Orchestina back another 10 million years from the previously oldest specimen in Turonian New Jersey amber. Despite being unknown as sedimentary fossils, Oonopidae occur in more fossil deposits than any other spider family and were already widespread by the Cretaceous. The family contains the oldest example of an extant spider genus along with Archaeidae, also from Burmese amber.     

Decadal change in wetland–woodland boundaries during the late 20th century reflects climatic trends

Wetlands are important and restricted habitats for dependent biota and play vital roles in landscape function, hydrology and carbon sequestration. They are also likely to be one of the most sensitive components of the terrestrial biosphere to global climate change. An understanding of relationships between wetland persistence and climate is imperative for predicting, mitigating and adapting to the impacts of future climate change on wetland extent and function. We investigated whether mire wetlands had contracted, expanded or remained stable during 1960–2000. We chose a study area encompassing a regional climatic gradient in southeastern Australia, specifically to avoid confounding effects of water extraction on wetland hydrology and extent. We first characterized trends in climate by examining data from local weather stations, which showed a slight increase in precipitation and marked decline in pan evaporation over the relevant period. Remote sensing of vegetation boundaries showed a marked lateral expansion of mires during 1961–1998, and a corresponding contraction of woodland. The spatial patterns in vegetation change were consistent with the regional climatic gradient and showed a weaker co‐relationship to fire history. Resource exploitation, wildland fires and autogenic mire development failed to explain the observed expansion of mire vegetation in the absence of climate change. We therefore conclude that the extent of mire wetlands is likely to be sensitive to variation in climatic moisture over decadal time scales. Late 20th‐century trends in climatic moisture may be related primarily to reduced irradiance and/or reduced wind speeds. In the 21st century, however, net climatic moisture in this region is projected to decline. As mires are apparently sensitive to hydrological change, we anticipate lateral contraction of mire boundaries in coming decades as projected climatic drying eventuates. This raises concerns about the future hydrological functions, carbon storage capacity and unique biodiversity of these important ecosystems.     

The social elite: Habitat heterogeneity,complexity and quality in granite inselbergs influence patterns of aggregation in Egernia striolata (Lygosominae: Scincidae)

Habitat heterogeneity, structural complexity and habitat quality are key features of the environment that drive species' distribution and patterns of biological organization. Traditionally, pattern‐based studies have focused on faunal responses to biological systems. However, the influence of non‐biological environments such as insular rock outcrops on patterns of vertebrate distribution is conceivably as important, but has received less attention. Granite inselbergs are a naturally heterogeneous and spatially‐limited habitat. As such, they provide an opportunity for investigating whether environmental attributes influence social behaviour in animals that use these kinds of habitat, particularly lizards that are well adapted to saxicoline environments. We applied ecological theory to investigate the influence of habitat heterogeneity, structural complexity and habitat quality on patterns of home‐site occupancy in the crevice skink Egernia striolata (Lygosominea: Scincidae) from insular granite outcrops located within fragmented agricultural landscapes. We compared home‐site occupancy among solitary juveniles, solitary adults and lizard aggregations. We found significant differences in home‐site occupancy between aggregations and solitary lizard outcrop attributes measured at multiple spatial scales. The probability of a home‐site being occupied by an aggregation increased where large rock masses were present, on northern aspects near the core of the outcrop and in structurally variegated landscapes. Significantly more aggregations occupied home‐sites surrounded by high boulder cover and crevice microhabitat. We provide evidence that geophysical attributes of granite inselbergs and landscape context can influence patterns of lizard aggregation. Thus, we clearly document the environmental correlations of variability in sociality among subpopulations of Egernia striolata.     

Phylogeny of ensign scale insects (Hemiptera: Coccoidea: Ortheziidae) based on the morphology of Recent and fossil females

The Ortheziidae (ensign scale insects) is a morphologically well‐defined family. The morphology and occurrence in the fossil record suggests a probable early origin of the family in scale insect evolution. The present phylogenetic analysis – based on 69 morphological characters of female ortheziids, using 39 exemplar Recent species – provides the first analytical assessment of relationships among living genera of the family, as well as the relationships of eight fossil species, based on complete, well‐preserved specimens in amber. Monophyly of the subfamilies Newsteadiinae, Ortheziinae and Ortheziolinae is supported, but Nipponortheziinae is found to be paraphyletic by inclusion of the Ortheziolinae. Thus, the subfamily Ortheziolinae is reduced in rank to tribe Ortheziolini stat.n. , which now includes Matileortheziola Kozár & Foldi, Ortheziolacoccus Kozár, Ortheziolamameti Kozár and Ortheziola?ulc. Consequently, the tribes Matileortheziolini, Ortheziolacoccini and Ortheziolamametini are synonymized ( syn.n. ) here under Ortheziolini. Five new species and one new genus of fossil ensign scales are described from three amber deposits: Burmorthezia gen.n. with type species Burmorthezia kotejai sp.n. and also B. insolita sp.n ., both in mid‐Cretaceous Burmese amber (98 Ma) and Arctorthezia baltica sp.n. in Eocene Baltic amber (c. 43 Ma) based on second‐instar nymphs; Mixorthezia kozari sp.n . and M. dominicana sp.n . in Miocene Dominican amber (c. 17 Ma) based on adult females. Fossil placements are unambiguous, with Burmorthezia forming a stem to crown‐group (Recent and Tertiary) Ortheziidae. A summary of described fossil ortheziids is provided.     

Small but not ephemeral: newly discovered species of Aphelinidae and Trichogrammatidae (Insecta: Hymenoptera: Chalcidoidea) from Eocene amber

New species of fossil Aphelinidae and Trichogrammatidae are described from middle Eocene (Lutetian) Baltic amber (41.3–47.8 Ma). A new subfamily, two new genera and three new species of Aphelinidae are described, with comments on their placement: Phtuaria fimbriae gen.n. , sp.n. in Phtuariinae subf.n. , Glaesaphytis interregni gen.n. , sp.n. and Centrodora brevispinae sp.n. These represent the first described true fossil Aphelinidae. Four new species of Trichogrammatidae are described: Mirufens illusionis sp.n. , Palaeogramma eos gen.n. , sp.n. , Pterandrophysalis plasmans sp.n. and Szelenyia terebrae sp.n. , thus expanding our knowledge of fossil Trichogrammatidae beyond the single previously described species. The presence of recognizable extant genera of Aphelinidae and Trichogrammatidae in the Eocene suggests that the morphology of these genera has been relatively invariant despite highly variable conditions during and since the Eocene. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:E9AD60B6‐3D56‐4E74‐AA54‐F7B91F4FDC79 .     

Diet,Prey Selection,and Predation Impact of Black-Backed Jackals in South Africa

ABSTRACT To investigate the role of black-backed jackals (Canis mesomelas) as predators, we studied diet, prey selection, and predation impact of jackals on 2 game ranches in South Africa that differed in ungulate diversity and biomass. Results showed that large (>15 kg) ungulate species dominated jackal diets throughout the year on both the less diverse (range of ingested biomass across seasons = 39–78%) and more diverse (26–69%) game ranch. Other important food items included medium-sized mammals (1–3 kg; 1–26%) and fruit (2–69%), whereas small mammals comprised 3–11% of ingested biomass across seasons on both sites. Jackals were not random in consumption of ungulates, and consumption patterns suggested jackals actively hunted certain species rather than consumed them as carrion. During ungulate birthing periods, jackals consumed almost exclusively those ungulate species that were hiders (i.e., fawns were hidden in tall vegetation away from herd) regardless of ungulate densities, suggesting that primarily fawns were preyed upon. Among hiders, there was a negative relationship (P = 0.01) between body size and percent of population consumed by jackals, indicating smaller species were more susceptible than larger species to jackal predation. Consequently, springbok (Antidorcas marsupialis) were always selected over other ungulate species on both sites, and this species was the most impacted by jackal predation. In contrast, ungulate species that were followers (i.e., fawns immediately followed mothers within protection of the herd) were scarcely or not at all consumed by jackals, regardless of body size or density. Medium-sized mammals were selectively consumed over ungulates, and there was a negative relationship (P < 0.01) between consumption of berries and ungulates, indicating alternative food resources influenced consumption of ungulates on our study sites. Our results will help wildlife managers in Africa identify ungulate species susceptible to jackal predation, and can be used to develop management strategies for reducing jackal predation in areas where it is problematic.     

Using metabolic fingerprinting of plants for evaluating nitrogen deposition impacts on the landscape level

Nitrogen emissions and atmospheric deposition are globally significant with the potential to alter ecosystem nutrient balance, provoking changes in vegetation composition. Shifts in plant biochemistry are good indicators of nitrogen pollution and have been used to monitor vegetation health. Fourier transform‐infrared (FT‐IR) spectroscopy has previously been shown to be a rapid and relatively inexpensive method for evaluating leaf biochemistry. In the present study, FT‐IR spectra were collected from Galium saxatile samples taken from sites across the United Kingdom. Spectral changes in the tissue samples were correlated with a gradient of N deposition using partial least squares regression analysis. We show that FT‐IR analysis of G. saxatile leaf tissue is an effective way to evaluate nitrogen deposition across the entire UK landscape.     

Oxygen Uptake and Antioxidant Responses of the Free-Living Diplomonad Hexamita sp.

ABSTRACT. The free-living anaerobic flagellate Hexamita sp. was observed to actively consume O₂ with a K_m O₂ of 13 μM. Oxygen consumption increased lineraly with O₂ tension up to a threshold level of 100 μM, above which it was inhibited. Oxygen uptake was supported by a number of substrates but probably not coupled to energy conservation as cytochromes could not be detected spectro-photometrically. In addition, inhibitors specific for respiratory chain components did not significantly affect O₂ uptake. Respiration was however, partially inhibited by flavoprotein and iron-sulfur protein inhibitors. NAD(P)H supported O₂ consumption was measured in both particulate and soluble fractions; this activity was partially inhibited by quinacrine. A chemosensory response was observed in cells exposed to air, however no response was observed in the presence of superoxide dismutase plus catalase. Catalase and nonspecific peroxidase activity could not be detected, but superoxide dismutase activity was present. Superoxide dismutase was sensitive to NaN₃ and H₂O₂ but not KCN, suggesting a Fe prosthetic group. Flow cytometric analysis revealed that thiol levels in live cells were depleted in the presence of t-butyl H₂O₂. The observed NADPH-driven glutathione reductase activity is believed to recycle oxidized thiols in order to re-establish reduced thiol levels in the cell. The corresponding thiol cycling enzyme glutathione peroxidase could not be detected. The ability to withstand high O₂ tensions (100 μM) would enable Hexamita to spend short periods in a wider range of habitats. Prologed exposure to O₂ tensions higher than 100 μM leads to irreversible damage and cell death.     

Relationships between root morphology and nitrogen availability in a recent theoretical model describing nitrogen uptake from soil

Abstract. The effect upon potential maximum nitrogen uptake rate of root morphology and nitrogen availability in soil was investigated using a simple nutrient transport model. Parameter values appropriate to an ecological or an agricultural context were introduced from the literature. The model predicted that the maximum uptake rate of nitrate was morphology-dependent only at extremely low concentrations. For ammonium, this was so for all realistic concentrations, assuming a high potential maximum uptake rate. The important concentration range for ammonium was two orders of magnitude greater than that for nitrate. With a lower potential maximum uptake rate of ammonium, root morphology was important below 15/igNg' soil, the concentration range in this case being a single order of magnitude greater than that for nitrate. The effects of root hairs were to decrease the threshold concentration for morphology-dependence, and to minimize root dry weight per unit volume of soil needed to maintain maximum nitrogen uptake rate. The effects of simultaneous mass flow of solution were negligible. The possible significance of these effects upon plant growth are discussed in relation to nitrogen availability.