Edge effects on fauna in fragmented seagrass meadows

Abstract Fragmented habitats are a common occurrence in many marine systems, but remain poorly studied in comparison to their terrestrial counterparts. Here, I show that crustaceans inhabiting fragmented Zostera seagrass meadows show a dramatic response (change in abundance) to patch edges, with 11 out of 12 tests showing greatest abundance at the boundary between sand and seagrass. These patterns occurred on a scale of 0.25–1 m around the patch edge. Changes in seagrass biomass are unlikely to explain this pattern, as seagrass biomass increased smoothly at the patch edge, and did not decline towards patch interiors. In contrast to crustaceans, only a few polychaete taxa responded to the patch edge (9 of 25 tests), and bivalves generally did not show a response (1 of 5 tests). These latter groups are predominantly infaunal, and their lack of response may be partly due to the presence of substantial quantities of seagrass root and rhizome material in the sand habitat, which was defined visually based on the lack of above‐ground seagrass components only.     

Structure and species richness in wetland continua on sandy soils in subtropical and tropical Australia

Net photosynthetic fixation of wetland plant communities is confined to the period of the year when the surface soil is not waterlogged and is thus well aerated. In the open‐structured vegetation continuum across freshwater wetlands on sandy soils in subtropical and tropical Australia, the sum of the foliage projective covers (FPCs) of the overstorey and understorey strata remains constant, while that of the overstorey decreases to zero as seasonal waterlogging (and anaerobic conditions) in the surface root systems increases. Density and height of the overstorey trees – of only one or two species – and species richness (number of species per hectare) in the understorey decreases along this waterlogging gradient. Melaleuca paperbark trees, possessing surface roots with cortical aerenchyma, may form a closed‐forest at the edge of the wetland continuum wherever there is a continuous flow of aerated water. As global warming progresses, an increase in air temperature in the atmosphere flowing over and through the wetland continuum during the short period of annual foliage‐growth will affect the combined FPCs of overstorey and understorey strata, as well as the leaf‐specific weights of all leaves throughout the plant community. With a reduction in net photosynthetic fixation, species richness of the plant community will slowly decline.     

Higher‐level phylogeny of the insect order Hemiptera: is Auchenorrhyncha really paraphyletic?

The higher‐level phylogeny of the order Hemiptera remains a contentious topic in insect systematics. The controversy is chiefly centred on the unresolved question of whether or not the hemipteran suborder Auchenorrhyncha (including the extant superfamilies Fulgoroidea, Membracoidea, Cicadoidea and Cercopoidea) is a monophyletic lineage. Presented here are the results of a multilocus molecular phylogenetic investigation of relationships among the major hemipteran lineages, designed specifically to address the question of Auchenorrhyncha monophyly in the context of broad taxonomic sampling across Hemiptera. Phylogenetic analyses (maximum parsimony, maximum likelihood and Bayesian inference) were based on DNA nucleotide sequence data from seven gene regions (18S rDNA, 28S rDNA, histone H3, histone 2A, wingless, cytochrome c oxidase I and NADH dehydrogenase subunit 4) generated from 86 in‐group exemplars representing all major lineages of Hemiptera (plus seven out‐group taxa). All combined analyses of these data recover the monophyly of Auchenorrhyncha, and also support the monophyly of each of the following lineages: Hemiptera, Sternorrhyncha, Heteropterodea, Heteroptera, Fulgoroidea, Cicadomorpha, Membracoidea, Cercopoidea and Cicadoidea. Also presented is a review of the major lines of morphological and molecular evidence for and against the monophyly of Auchenorrhyncha.     

Cuticular morphology and aspects of the ecology and fossil history of North Queensland rainforest Proteaceae

Cuticles of North Queensland rainforest Proteaceae were examined using light and scanning electron microscopy. The genera of North Queensland rainforest Proteaceae are mostly endemic and composed of one or few species, with greatest diversity in the granitic uplands of the region. Knowledge of cuticular morphology may be an important tool in determining the true affinities of several undescribed taxa in the region and can be used to explore hypotheses relating to the history of the Proteaceae. Some species exhibit purported xeromorphic features of thick cuticles, sunken stomates and dense trichome cover on the abaxial surface. Grevillea , Banksieae and Stenocarpus are believed to have radiated into open, much less mesic environments. In the former two taxa this can be interpreted in terms of xeromorphic features expressed in their cuticular morphologies, whereas in Stenocarpus amphistomaty in species of open habitats suggests an alternative mode of evolution more related to physiological factors. Several Cainozoic proteaceous macrofossils temporally and spatially far removed from North Queensland possess cuticular morphologies very similar or identical to extant rainforest taxa in the region.     

Morphology and systematics of anthracomartidae (Arachnida: Trigonotarbida)

Abstract: X‐ray microtomography (XMT) was applied to three species of the extinct arachnid order Trigonotarbida, hosted in siderite nodules from the late Carboniferous British Middle Coal Measures. All three, Cryptomartus hindi ( Pocock, 1911 ), Cleptomartus plautus ( Petrunkevitch, 1949 ) and Maiocercus celticus ( Pocock, 1902 ), belong to the family Anthracomartidae. As well as providing interactive three‐dimensional visualisations of their likely appearance in life, XMT study has resolved new morphological detail, yielding key data about the likely stance and habitus of these early arachnids. Similarities in the form of the carapace, eyes and coxosternal region between anthracomartids and the Devonian genus Palaeocharinus Hirst, 1923 are highlighted. Analogies in limb disposition are drawn between anthracomartids and modern crab spiders (Araneae: Thomisidae), which exhibit sit‐and‐wait style predatory behaviour. Anthracomartids are relatively common fossils at many Coal Measures localities. Although they appear to exhibit limited morphological variation, numerous genera and species have been proposed in the literature, often distinguished from each other on rather trivial characters. From our reconstruction of well‐preserved examples, we have resolved a number of common features likely to be present in a typical anthracomartid. Comparisons to this model suggest that the characters on which many anthracomartid genera are distinguished may be artefacts of preservation. We hence treat Promygale Fri?, 1901 , Brachylycosa Fri?, 1904 , Perneria Fri?, 1904 , Coryphomartus Petrunkevitch, 1945 , Cryptomartus Petrunkevitch, 1945 , Pleomartus Petrunkevitch, 1945 , Cleptomartus Petrunkevitch, 1949 and Oomartus Petrunkevitch, 1953 as junior synonyms of the type genus of the family, Anthracomartus Karsch, 1882 . Only the genera Brachypyge Woodward, 1878 and Maiocercus Pocock, 1911 are additionally retained. Within Anthracomartus, Cleptomartus planus Petrunkevitch, 1949 , Cryptomartus meyeri Guthörl, 1964 , Cleptomartus hangardi Guthörl, 1965 and Cryptomartus rebskei Brauckmann, 1984 are treated as junior synonyms of A. hindi Pocock, 1911 (all syn. nov.). Cleptomartus plautus Petrunkevitch, 1949 and Anthracomartus denuiti Pruvost, 1922 are treated as junior synonyms of A. priesti Pocock, 1911 (both syn. nov.).