Antechinus

Antechinus View in CoL (order Dasyuromorphia ) is a genus of small, carnivorous marsupials endemic to Australia, occurring in all states and mainland territories ( Van Dyck & Strahan, 2008). They are abundant throughout the species-rich mesic zone of Australia and thus are believed to play an important ecological role as a microcarnivore and in pollen transfer ( Carthew & Goldingay, 1997; Goldingay, 2000; Dickman, 2014). The genus has become well-known as one of a few mammal genera that undertake semelparous mating, where all males die at the close of a frenetic 1–3 week synchronized annual breeding period ( Woolley, 1966). Because of this, Antechinus is sometimes used as a model organism in reproductive biology ( Naylor et al., 2008) and is of interest in ageing research (e.g. Sergiev et al., 2015; Goldsmith, 2016).

Dasyuromorphia View in CoL is the principal clade of Australasian carnivorous marsupials, which include four families: Malleodectidae , known only from the fossil record, the recently extinct Thylacinidae View in CoL , Myrmecobiidae View in CoL (the monotypic numbat, Myrmecobius fasciatus Waterhouse, 1836 View in CoL ) and the species-rich Dasyuridae View in CoL (~75 extant species) ( Jackson & Groves, 2015; Archer et al., 2016). Dasyuridae View in CoL contains two subfamilies: the small-sized Sminthopsinae View in CoL and the larger Dasyurinae View in CoL . Within Dasyurinae View in CoL there are two tribes: Dasyurini View in CoL , which contains the largest extant Dasyuromorphia View in CoL species, the quolls (genus Dasyurus View in CoL , 0.3–7 kg), the Tasmanian devil ( Sarcophilus harrisii (Boitard, 1841) View in CoL , 6–14 kg) and a number of smaller genera, and the Phascogalini View in CoL ( Van Dyck et al., 2013; Jackson & Groves, 2015). Early work, largely pre-dating modern genetic techniques, recognized Antechinus View in CoL in New Guinea, but genetic studies have since consistently resolved all New Guinean species in the genus Murexia View in CoL ( Baverstock et al., 1982; Kirsch et al., 1990; Krajewski et al., 1994, 1996, 2000, 2007; Retief et al., 1995; Armstrong et al., 1998; Mitchell et al., 2014; Westerman et al., 2015). Murexia View in CoL , Antechinus View in CoL and the arboreal Australian genus Phascogale View in CoL constitute the tribe Phascogalini View in CoL . Relationships between the three Phascogalini View in CoL genera are uncertain. Molecular studies have generally resolved Antechinus View in CoL as sister to Murexia View in CoL (e.g. Krajewski et al., 2007; Mitchell et al., 2014). However, a recent molecular study ( Westerman et al., 2015) resolved Murexia View in CoL and Phascogale View in CoL as sister genera, a result in line with Van Dyck’s (2002) morphological analysis.

While higher-level systematic relationships in dasyurids are largely resolved ( Mitchell et al., 2014; Westerman et al., 2015), species-level relationships and taxonomy of a number of genera remain uncertain (e.g. Blacket et al., 2006; Westerman et al., 2008, 2016). A number of genetic studies have aimed to resolve the systematic position of all Antechinus species ( Baverstock et al., 1982; Krajewski et al., 1994, 1996, 1997, 2000, 2007; Retief et al., 1995; Armstrong et al., 1998). However, since 2012 five additional species of Antechinus View in CoL have been named on the combined basis of morphology (pelage, external and craniodentary features), ecology, geographic distribution and genetic differences ( Baker et al., 2012, 2013, 2014, 2015). Unfortunately, the genetic analysis that was included in these taxonomic studies could only be based on partial sequence data for two genes ( Baker et al., 2012, 2013, 2014, 2015). While clearly supporting the uniqueness of each new taxon, these genetic reconstructions were not powerful enough to fully resolve their relative systematic position with congeners. For example, these studies were the first molecular research to include A. adustus Thomas, 1923 View in CoL and A. subtropicus Van Dyck & Crowther, 2000 View in CoL , whose systematic positions were rendered uncertain by the new discoveries. Therefore, the relative placements of seven of the 15 Antechinus species and a number of subspecies have not been tested in a comprehensive molecular study. The current research aims to resolve these knowledge gaps by sequencing for the first time all 15 Antechinus species and their subspecies with a comprehensive multi-gene dataset of two mitochondrial and four nuclear genes. The present analysis also allows the timescale of Antechinus View in CoL evolution to be estimated for all species for the first time and possible biogeographic drivers of their diversification to be explored. Furthermore, while Mitchell et al. (2014) performed ancestral habitat reconstruction for marsupials, they were able to include only eight Antechinus species. We have, therefore, reconstructed the ancestral habitat of all 15 described species of Antechinus View in CoL . Accurate taxonomic and systematic delineation underpins effective conservation management ( Mace, 2004). Three Antechinus species and one subspecies have been identified as at risk of extinction under Australian law within the last three years. This includes two of the recently discovered species. The work presented here will therefore be of importance when designing future conservation actions and priorities.