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| Australian Trapdoor Spider, Moggridge rainbow was descendant to African trapdoor spider |
It could be one of the most dangerous voyage that spiders have been done. The Moggridgea rainbow which is one of the trapdoor spiders live in Kangaroo Island, Australia and it was originated from Africa. This spider has similar genes with 33 other species which are native to Africa [1]. However, for evolutionist this voyage is something interesting because the reason for the spiders might have sailed throughout Indian Ocean to Australia was impossible for only food availability. Surprisingly, the researchers from Adelaide University who analyze the biological aspect said that the segregation of the spiders were diverged between two and 16 million years ago after Africa-Gondwana separated [2].
As the researcher suggested that the trapdoor spiders of Moggridgea rainbow travelled throughout the Indian ocean. One of studies reported that another genus of trapdoor spiders, Idiops joida, inhabits the Uttara Kannada district of Karnataka, Western Ghats, India and builds its burrow which is able to adapt in the environment [3]. This report indicated that the trapdoor spiders travelled across India and the natural selection proceeded the evolution.
However, the main question is how the researchers suggested that the Moggridgea rainbow has African ancestors. The suggestion came out from the family of Moggridgea which is the Migidae. The Migidae is categorized as a family of Mygalomorphae which has heavy bodied, stout legged and it has similar aspect in fang, for instance tarantulas [4]. So, biologically speaking, the Moggridgea rainbow is classified as Migidae which is the same on several genera occurring in Africa, Madagascar, New Zealand, New Caledonia, South America and Australia [5].
After analysing the parameters of Moggridgea rainbow in Kangaroo Island, Australia, the data showed that there was similarity in nuclear genes which demonstrated validity of members between Australian trapdoor spiders and African trapdoor spider. In order to understand the result and relationship between two trapdoor spiders, the researchers performed molecular clock analysis. The dating which was employed to the molecular showed that the inter-specific divergence was occurred around 2.27 to 16.02 million years ago [6].
References
[1] A. Masterson, "Fantastic Voyage: Spiders might have rafted across the Indian Ocean," Cosmos Magazine, 03 August 2017. [Online]. Available: https://cosmosmagazine.com/biology/fantastic-voyage-spiders-might-have-rafted-across-the-indian-ocean. [Accessed 03 August 2017].
[2] U. o. A. "Trapdoor spiders crossed Indian Ocean to get to Australia," The University of Adelaide, 03 August 2017. [Online]. Available: http://www.adelaide.edu.au/news/news93942.html. [Accessed 03 August 2017].
[3] N. Gupta, S. K. Das and M. Siliwal, "Natural history of the trapdoor spider Idiops joida Gupta et al 2013 (Araneae: Idiopidae) from the Western Ghats in India," Journal of Asia-Pacific Biodiversity, no. 8, pp. 38-42, 2915.
[4] W. "Mygalomorphae," Wikipedia, 12 June 2017. [Online]. Available: https://en.wikipedia.org/wiki/Mygalomorphae. [Accessed 03 August 2017].
[5] C. Griwold and J. Ledford, "A monograph of the migid trap door spiders of Madagascar and review of the world genera (Araneae, Mygalomorphae, Migidae).," Occasional papers of the California Academy of Sciences, no. 151, pp. 1-120, 2001.
[6] S. Harrison, M. S. Harvey, S. J. B. Cooper, A. D. Austin and M. G. Rix, "Across the Indian Ocean: A remarkable example of transoceanic dispersal in an austral mygalomorph spider," PLOS One Tenth Anniversary, 2017.
[7] Image is downladed from https://edge.alluremedia.com.au and credited by Nick Birks