A new model Gondwanan taxon: systematics and biogeography of the harvestman family Pettalidae (Arachnida, Opiliones, Cyphophthalmi), with a taxonomic revision of genera from Australia and New Zealand

Abstract

The phylogeny of the temperate Gondwanan harvestman family Pettalidae is investigated by means of a new morphological matrix of 45 characters, and DNA sequence data from five markers, including two nuclear ribosomal genes (18S rRNA and 28S rRNA), one nuclear protein coding gene (histone H3), and two mitochondrial genes-one protein coding (cytochrome c oxidase subunit I) and one ribosomal (16S rRNA). Phylogenetic analyses using an array of homology schemes (dynamic and static), criteria (parsimony and maximum likelihood), and sampling strategies (optimal trees versus Bayesian phylogenetics) all agree on the monophyly of Pettalidae as well as several of its subclades, each of which is restricted to a modern landmass. While most genera as traditionally defined are monophyletic, Rakaia and Neopurcellia, distributed across Queensland (Australia) and New Zealand, are not. Instead, the species from Queensland, previously described under three genera, constitute a well-supported clade, suggesting that in this case biogeography prevails over traditional taxonomy. A taxonomic emendation of the genera from Queensland and New Zealand is presented, and the new genus Aoraki is erected to include the species of the New Zealand denticulata group. A biogeographical hypothesis of the relationships of the former temperate Gondwana landmasses (with the exception of Madagascar) is presented, although ambiguity in the deep nodes of the pettalid tree renders such inference provisional.

'Moa's Ark' or 'Goodbye Gondwana': is the origin of New Zealand's terrestrial invertebrate fauna ancient, recent or both?

“…1). However, recent taxonomic revision by Boyer and Giribet (2007), based on a combined analysis of morphological and molecular data, refutes that hypothesis. The mite harvestmen of Queensland were found to be monophyletic and are now grouped in a single genus (Austropurcellia) with no New Zealand representatives.…”

“…Notwithstanding these gaps in our knowledge, many commentators have already debunked the concept of NZ as a Gondwanan relictual ark (McGlone 2005;Waters & Craw 2006;Trewick et al 2007;Landis et al 2008)' (Wallis and Trewick 2009: p. 3565). The same authors do concede (p. 3565) that '[m]ore work on arthropods is needed; they are likely to include recent and ancient dispersers as well as Gondwanan relicts (Gressitt 1961(Gressitt , 1970Boyer & Giribet 2007)'. In another paper Goldberg et al (2008) review the molecular evidence for several New Zealand terrestrial animals, concluding that the New Zealand biota is 'in most respects, more like that of an oceanic archipelago than a continent' (p. 3319).…”

“…2a-d) Mite harvestmen (Arachnida, Opiliones, Cyphophthalmi), and the family Pettalidae in particular, have played a role in the study of Gondwanan and New Zealand biogeography. The family has a typical temperate Gondwanan distribution, with species in Chile, South Africa, Madagascar, Sri Lanka, Australia and New Zealand (but not in New Caledonia, which hosts a member of a tropical Gondwanan clade, the family Troglosironidae) (Boyer et al 2007b;Boyer and Giribet 2007). Originally, New Zealand's mite harvestmen were described in two genera, Rakaia and Neopurcellia, each of which also included species in Queensland, Australia, implying a shared evolutionary history spanning the Tasman Sea (Fig.…”

Welcome back New Zealand: regional biogeography and Gondwanan origin of three endemic genera of mite harvestmen (Arachnida, Opiliones, Cyphophthalmi)

“…These characters were defined in our 2007 study of the phylogeny of Pettalidae and references therein (Giribet & Boyer, 2002;Giribet, 2003a;de Bivort & Giribet, 2004;Boyer & Giribet, 2007) (Appendix S2). When appropriate specimens were available, they were dissected and mounted for examination using an FEI Quanta 200 scanning electron microscope (SEM).…”

“…The New Zealand archipelago is home to 57% of the described pettalid mite harvestman species, most of which were first documented by local arachnologist Ray Forster (Forster, 1948(Forster, , 1952Boyer & Giribet, 2003, 2007. Three genera of these animals are endemic to New Zealand: Neopurcellia Forster, 1948, including only the widespread species Neopurcellia salmoni, found in the western South Island between Lake Kaniere and Lake Te Anau; Rakaia Hirst, 1925, found on Stewart Island, along the south and east coasts of the South Island and throughout Nelson and in the North Island as far north as Lake Waikaremoana; and Aoraki Boyer & Giribet, 2007, with a distribution ranging throughout the North Island and in the South Island as far south as Aoraki/Mount Cook in the South Island (Boyer & Giribet, 2007) (Fig. 2).…”