Dolomedes schauinslandii

Rangatira spiders are one of Aotearoa’s heaviest spider (up to 12cm across; a female was found that weighed 5.1g!), and are only found on the offshore islands of Rēkohu | Wharekauri | Chatham Islands. Like most spiders, Rangatira spiders are sexually dimorphic – the females are heavier than the males. They are also considered roaming hunters, which means they don’t build webs. Instead, they catch prey on tree trunks (they love eating wētā!). 

Rangatira spider populations are at risk. They were first described from specimens collected on Rangihaute | Rangiauria | Pitt Island, but appear to have gone extinct there since the introductions of mice. They are now only found on Hokorereoro | Rangatira | South East Island (famously found in the long drop), Maung’Rē | Mangere, and Motuara | Houruakopara (offshore islands of Rēkohu | Wharekauri | Chatham Islands), which are all rodent-free.

Female Rangatira spiders, like their relatives the nursery web spiders, construct a dense silk enclosure on the tips of vegetation to act as a shelter for their young until they are ready to make their way out into the world. This looks very similar to the nursery webs that are a familiar sight on roadside gorse and broom throughout much of Aotearoa|New Zealand, but it’s about twice as large.

Other species in this genus do some crazy mating stuff – genital mutilation, spontaneous male death, sexual cannabilism, but many of the secrets of this particular species are still to be discovered.

Check these links for more info on the Rangatira Spider in NZ

Wikipedia: Information on Dolomedes schauinslandi

Secrets of the Rangatira spider

Giant spiders and other critters of Rangatira Island Chatham Islands

images

Click on the image to visit the official observation.

iNaturalist.nz image © Mark Anderson
iNaturalist.nz image @ matt-walters