Zoogeography of the southern New Zealand, Tasmanian and southern African ascidian fauna

Abstract

We studied the relationships among the ascidian fauna of southern New Zealand, Tasmania, and southern Africa, considering main currents and surface water temperature. We constructed a presence/absence matrix of 494 ascidian species from these regions (which were also divided into provinces) for 28 biogeographical worldwide regions using published records. Biogeographical areas were classified using cluster analysis combined with non‐metric multidimensional scaling ordination. The region classification separated Vema Seamount because of the low number of citations and the high number of ascidian endemism owing to an island effect. The Tasmanian, southern African and southern New Zealand regions formed separate groups. The ascidian fauna was dominated by endemic species in southern New Zealand (43%) and southern Africa (45%), whereas southern Australian species dominated the Tasmanian fauna (41%).

Keywords:

• biogeographical regions
• Ascidiacea
• Tunicata
• cluster analysis