Sea-level changes and palaeo-ranges: reconstruction of ancient shorelines and river drainages and the phylogeography of the Australian land crayfish Engaeus sericatus Clark (Decapoda: Parastacidae )

Historical sea levels have been influential in shaping the phylogeography of freshwater-limited taxa via palaeodrainage and palaeoshoreline connections. In this study, we demonstrate an approach to phylogeographic analysis incorporating historical sea-level information in a nested clade phylogeographic analysis (NCPA) framework, using burrowing freshwater crayfish as the model organism. Our study area focuses on the Bass Strait region of southeastern Australia, which is marine region encompassing a shallow seabed that has emerged as a land bridge during glacial cycles connecting mainland Australia and Tasmania. Bathymetric data were analysed using Geographical Information Systems (GIS) to delineate a palaeodrainage model when the palaeocoastline was 150 m below present-day sea level. Such sea levels occurred at least twice in the past 500 000 years, perhaps more often or of larger magnitude within the last 10 million years, linking Victoria and Tasmania. Inter-locality distance measures confined to the palaeodrainage network were incorporated into an NCPA of crayfish (Engaeus sericatus Clark 1936) mitochondrial 16S rDNA haplotypes. The results were then compared to NCPAs using present-day river drainages and traditional great-circle distance measures. NCPA inferences were cross-examined using frequentist and Bayesian procedures in the context of geomorphological and historical sea-level data. We found distribution of present-day genetic variation in E. sericatus to be partly explained not only by connectivity through palaeodrainages but also via present-day drainages or overland (great circle) routes. We recommend that future studies consider all three of these distance measures, especially for studies of coastally distributed species.

Teaching philosophy : moving from face-to-face to online classrooms

This article explores the similarities and differences between Canadian and Australian university teachers’ face-to-face and online teaching approaches and philosophies. It presents perspectives on teaching face-to-face and online in two comparable Canadian and Australian universities, both of which offer instruction in these two modes. The key research question was to determine if moving from face-to-face instruction to on-line teaching results in new teaching approaches or in a creative blend of those developed within each teaching modality. Qualitative data were collected using an open-ended survey, which asked participants for their thoughts on their face-to-face (f2f) and online teaching experiences. Quantitative data were collected using the “Teaching Perspectives Inventory,” which assessed participants’ teaching approaches and philosophies in terms of their beliefs, intentions, and actions. The authors’ conclusions address the issue of assisting teachers to successfully make the transition from traditional teacher-centred to newly emerging learner-centred teaching approaches in distributed classrooms.

“Critchley is Žižek” : in defence of critical political philosophy

In an ironically Žižekian manner, this paper argues that Simon Critchley and Slavoj Žižek's apparent political disagreement (ludic reformist versus strident revolutionary) conceal a common set of preconditions and presuppositions. These presuppositions can be summed by the slogan “the forgetting of political philosophy”, which more specifically means the forgetting of the difference between philosophy and political life, and the reflective need to find mediations between the two. Critchley's turn to humour honours the notion that politics is about the realm of appearances, while Žižek's frank avowal of the “diabolical evil” of the subject of the death drive makes patently clear the dangers posed by a “politics of Truth”.