''Moggridgea rainbowi'', also called the Australian trapdoor spider, is a small spider endemic to

Kangaroo Island Kangaroo Island (, ) is Australia's third-largest island, after Tasmania and Melville Island, Northern Territory, Melville Island. It lies in the state of South Australia, southwest of Adelaide. Its closest point to the mainland is Snapper Poi ...

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...

. The spider was first recorded in 1919.

Distribution

The spider's habitat is in burrows just above the high tide mark. The spider has been identified and studied from two sites on Kangaroo Island; the genomes from the two sites 80 km apart indicate that the groups diverged 1 to 6 million years ago, reflective of juveniles not migrating far from their maternal sites. The most closely related species is considered to be the African '' M. intermedia''. A study has indicated that ''M. rainbowi'' is likely to have reached Australia from Africa between 2 and 16 million years ago. Given that this time is intermediate between the separation of Australia from Gwondwana (circa 95 million years ago) and the arrival of humans into Australia, it has been proposed that the spiders may have arrived by

oceanic dispersal Oceanic dispersal is a type of biological dispersal that occurs when Terrestrial animal, terrestrial organisms transfer from one land mass to another by way of a sea crossing. Island hopping is the crossing of an ocean by a series of shorter jour ...

, such as by rafting vegetation.

Behaviour

The spiders live in short burrows, approximately 6cm deep. Young spiders live with their mothers before building their own burrows nearby.

2019-2020 bushfires

All known Western River populations were destroyed during the 2019-2020 Australian bushfires, one of which burned a third of Kangaroo Island. Only 5 survivors have since been reported. Later surveys found more individuals across the island, with some of these populations (including a newly-discovered inland population) being stable, but found the Western River populations to still be at critically low levels.

References

{{Taxonbar, from=Q27502908 Migidae Spiders of Australia Spiders described in 1919