Tree Trapdoor Spiders - Family: Migidae
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In general the Migidae small to large burrowing spiders that create tunnels with trapdoors. As the name suggests, they are often found in trees where they tunnel into the bark or rotting wood to build there hide-outs. Once covered the opening is extremely difficult to spot and so sightings of these spiders are quite rare. Some species built their burrows into the ground and lay in ambush for their prey there. The usual colours apply for these spiders as it does for other Mygalomorphs although they trend to be bit lighter in colour overall and reddish-brown is more common.
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Distribution of the Tree Trapdoor Spiders is typically Gondwanan with the Migidae found only in the southern hemisphere in parts of South America, Africa, Madagascar, Australia and New Zealand. Australia can boast of at least twelve species of which only two might be found in the Northern Rivers. That we know of anyway, as their ability to camouflage their hiding spot is better than that of most.
Appearance wise many species look alike and distinguishing between them is difficult; often the structure of the female internal genitalia being the deciding factor. |
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At present a total of 103 species in 11 genera have been described world wide but these numbers may grow over time as more species are discovered. Distribution of individual species tends to be localised and as a family they are often considered relicts, aka 'living fossils'. Even though there is not much of a fossil record of them. There are also certain pitfalls associated with the term 'relict' that may cause false assumptions to be made about former distribution and about the morphological features of the species in an evolutionary sense. Nevertheless, many species may well be rare and /or threatened and consequently at risk from the changes our world is currently going through.
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Heteromigas terraereginae (possible occurrence)
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Migas variapalpus (likely occurrence)
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Taxonomy:
Phylum: Arthropoda (Arthropods)
> Subphylum: Chelicerata (Chelicerates)
> Class: Arachnida (Arachnids)
> Order: Aranea (Spiders)
> Suborder: Mygalomorphae (Mygalomorphs)
> Superfamily: Avicularioidea
> Family: Migidae (Tree Trapdoor Spiders)
> Genus: Heteromigas
> Species: H. terraereginae ^
> Genus: Migas
> Species: M. variapalpus *
* = likely
^ = possibly
References and links:
> Grandcolas, P., Nattier, R. and Trewick, S., (2014). 'Relict species: A relict concept?' Trends in Ecology & Evolution. 10.1016/j.tree.2014.10.002.
> Griswold, C.E. and Ledford, J., (2001). '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 151: 1-120.
> Harvey, M.S., Main, B.Y., Rix, M.G. and Cooper, S.J.B., (2015). 'Refugia within refugia: in situ speciation and conservation of threatened Bertmainius (Araneae: Migidae), a new genus of relictual trapdoor spiders endemic to the mesic zone of south-western Australia.' Invertebrate Systematics 29(6): 511-553. doi:10.1071/IS15024
https://www.mindat.org/taxon-9562.html
https://wsc.nmbe.ch/family/57/Migidae
> Grandcolas, P., Nattier, R. and Trewick, S., (2014). 'Relict species: A relict concept?' Trends in Ecology & Evolution. 10.1016/j.tree.2014.10.002.
> Griswold, C.E. and Ledford, J., (2001). '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 151: 1-120.
> Harvey, M.S., Main, B.Y., Rix, M.G. and Cooper, S.J.B., (2015). 'Refugia within refugia: in situ speciation and conservation of threatened Bertmainius (Araneae: Migidae), a new genus of relictual trapdoor spiders endemic to the mesic zone of south-western Australia.' Invertebrate Systematics 29(6): 511-553. doi:10.1071/IS15024
https://www.mindat.org/taxon-9562.html
https://wsc.nmbe.ch/family/57/Migidae
Photographic contributions: