Historical biogeography of Australian Rhamnaceae, tribe Pomaderreae

Abstract

Aim To discover the pattern of relationships of areas of endemism for Australian genera in the plant family Rhamnaceae tribe Pomaderreae for comparison with other taxa and interpretation of biogeographical history. Location Australian mainland, Tasmania and New Zealand. Methods A molecular phylogeny and geographic distribution of species within four clades of Pomaderreae are used as a basis for recognition of areas of endemism and analysis of area relationships using paralogy‐free subtrees. The taxon phylogeny is the strict consensus tree from a parsimony analysis of 54 taxa, in four clades, and sequence data for the internal transcribed spacer regions of ribosomal DNA (ITS1‐5.8S‐ITS2) and the plastid DNA region trnL‐F. Results The biogeographical analysis identified five subtrees, which, after parsimony analysis, resulted in a minimal tree with 100% consistency and seven resolved nodes. Three sets of area relationships were identified: the areas of Arnhem and Kimberley in tropical north Australia are related based on the phylogeny of taxa within Cryptandra; the moister South‐west of Western Australia, its sister area the coastal Geraldton Sandplains, the semi‐arid Interzone region and arid Western Desert are related, based on taxa within Cryptandra, Spyridium, Trymalium and Pomaderris; and the eastern regions of Queensland, McPherson‐Macleay, south‐eastern New South Wales (NSW), Victoria, southern Australia, Tasmania and New Zealand are related based on Cryptandra, Pomaderris and Spyridium. Tasmania and NSW are related based entirely on Cryptandra, but the position of New Zealand relative to the other south‐eastern Australian regions is unresolved. Main conclusions The method of paralogy‐free subtrees identified a general pattern of geographic area relationships based on Australian Pomaderreae. The widespread distribution of clades, the high level of endemicity and the age of fossils for the family, suggest that the Pomaderreae are an old group among the Australian flora. Their biogeographical history may date to the early Palaeogene with subsequent changes through to the Pleistocene.

Towards an Australian Bioregionalisation Atlas: A provisional area taxonomy of Australia’s biogeographical regions

“…(Fig. 2 Ladiges et al 2005Ladiges et al : 1913 Diagnosis. "The Interzone is intermediate between the tall wet forests and the arid, desert region to the east" (Ladiges et al 2011: 32).…”

“…The following provisional revision contains 19 regions and 36 sub-regions that cover the entire Australian continent and surrounding waters. Hampton Ladiges et al 2005 The taxonomy and area nomenclature follows the recommended hierarchy set out in the ICAN (Ebach et al 2008). In addition, following the notion of priority, existing names are used in favour of new names for regions.…”

“…2) Hampton Ladiges et al 2005Ladiges et al : 1913 Diagnosis. "Coastal dry region south of the Nullabor" (Ladiges et al 2005(Ladiges et al : 1913. Type locality.…”

“…However, Burbidge (1960) preferred the use of Gardener's definition, which is used above. Gardener's province is divided into four areas by Ladiges et al (2005Ladiges et al ( , 2011 based on the IBRA bioregions. These include Geraldton Sandplains (Ladiges et al 2005), Jarrah Forest, Wheatbelt and Goldfields (Ladiges et al 2011).…”

A revised area taxonomy of phytogeographical regions within the Australian Bioregionalisation Atlas

“…(Fig. 3) (Southwest Australia Diels: 1906: 40) (Southwest Crisp et al 1995: 460) (Southwest Australian Floristic Region Hopper & Gioia 2004: 633) (South-West WA Interzone Jarrah Forest Ladiges et al 2011: 32) (South-West WA Geraldton Sandplains Ladiges et al 2005Ladiges et al : 1913 (South-West WA Interzone Wheatbelt Ladiges et al 2011: 32) (Goldfields Ladiges et al 2011: 32) Southwest Australia Ebach et al 2013: 324 Emended diagnosis. Triangular crescent shaped area between Shark Bay, Western Australia and Eucla in South Australia, extending as far inland as Lake Barlee, Western Australia.…”