The genus Unixenus Jones, 1944 (Diplopoda, Penicillata, Polyxenida) in Australia

The penicillate genus Unixenus Jones, 1944 is widespread, with species found in Africa, Madagascar, India and Australia. Each of the two Australian species was originally described from single samples from Western Australia. In this study, collections of Penicillata from museums in all states of Australia were examined to provide further details of the two described species, to revise the diagnoses for both the genus and the species, and to better understand the distribution of the two species in Australia. In addition, two new species Unixenus karajinensis sp. n. and Unixenus corticolus sp. n. are described.

Four new species of Unixenus Jones, 1944 (Diplopoda, Penicillata, Polyxenida) from Australia

Unixenus carnarvonensis sp. n., U. corringlensis sp. n., U. barrabaensis sp. n. and U. myallensis sp. n. are described from Australia. A revised diagnosis of U. karajinensis and new details on the distribution of the species are given. A key is presented to 10 of all 11 currently known species of the genus.

High muscle mitochondrial volume and aerobic capacity in a small marsupial (Sminthopsis crassicaudata) reveals flexible links between energy-use levels in mammals

We investigated the muscle structure-function relationships that underlie the aerobic capacity of an insectivorous, small (~15?g) marsupial, Sminthopsis crassicaudata (Family: Dasyuridae), to obtain further insight into energy use patterns in marsupials relative to those in placentals, their sister clade within the Theria (advanced mammals). Disparate hopping marsupials (Suborder Macropodiformes), a kangaroo (Macropus rufus) and a rat-kangaroo (Bettongia penicillata), show aerobic capabilities as high as those of 'athletic' placentals. Equivalent muscle mitochondrial volumes and cardiovascular features support these capabilities. We examined S. crassicaudata to determine whether highly developed aerobic capabilities occur elsewhere in marsupials, rather than being restricted to the more recently evolved Macropodiformes. This was the case. Treadmill-trained S. crassicaudata attained a maximal aerobic metabolic rate (VO2,max or MMR) of 272ml O2min-1kg -1 (N=8), similar to that reported for a small (?20g), 'athletic' placental, Apodemus sylvaticus, 264ml O2min -1kg-1. Hopping marsupials have comparable aerobic levels when body mass variation is considered. Sminthopsis crassicaudata has a basal metabolic rate (BMR) about 75% of placental values but it has a notably large factorial aerobic scope (fAS) of 13, elevated fAS also features in hopping marsupials. The VO2,max of S. crassicaudata was supported by an elevated total muscle mitochondrial volume, which was largely achieved through high muscle mitochondrial volume densities, Vv(mt,f), the mean value being 14.0±1.33%. These data were considered in relation to energy use levels in mammals, particularly field metabolic rate (FMR). BMR is consistently lower in marsupials, but this is balanced by a high fAS, such that marsupial MMR matches that of placentals. However, FMR shows different mass relationships in the two clades, with the FMR of small (<, 125 g) marsupials, such as S. crassicaudata, being higher than that in comparably sized placentals, with the reverse applying for larger marsupials. The flexibility of energy output in marsupials provides explanations for this pattern. Overall, our data refute widely held notions of mechanistically closely linked relationships between body mass, BMR, FMR and MMR in mammals generally.

Phryssonotus novaehollandiae Silvestri, 1923 : the sole Australian representative of the millipede Family Synxenidae

Examination of synxenid millipedes from a number of collections confirms that Phryssonotus novaehollandiae is the sole representative of the genus and family in Australia. P. novaehollandiae was found to have the most widespread distribution of any native Australian millipede species. It occurs in a range of well-drained habitats including heathlands, woodlands and coastal scrub. Several thelytokous (female only) populations were found in coastal areas of south eastern Australia.

A technique for examination of diagnostic characters of penicillate millipedes

We describe a simple method for examination of penicillate millipedes. The internal tissues are dissolved and the stain Fast Green used to give excellent contrast for dissection and to provide clear visualisation of characters necessary for identification of both freshly collected and museum specimens.