Mygalomorphs  -  Suborder:  Mygalomorphae
      The third main group of spiders, after the Araneomorphae and Mesothelae, are the Mygalomorphae or Mygalomorphs.   This suborder is divided into two superfamlies. Firstly, the Atypoidea which contains 104 species in 10 genera in 5 families, which are limited to parts of North America, Europe and parts of Asia.  And secondly, the Avicularioidea, a large superfamily containing 3,420 species in 368 genera in 26 families.  The Avicularioids can be found on every continent except Antarctica, and includes many of the more famous spiders such as Tarantulas, Mouse Spiders, Australian Funnelweb Spiders and Trapdoor Spiders.  What sets the Mygalomorphs apart from the other spiders is the fact that their fangs do not cross each other when at rest.  As well as that, the Mygalomorphs usually live longer than just a single year as Araneomorph spiders do.  Many do not reach sexual maturity until six or seven years old.  The oldest documented Mygalomorph died at the ripe old age of 43 years.  She was a Trapdoor Spider that was monitored during a long-term study in Western Australia who lived and raised her young in the same burrow all of her life.  Her name was No. 16.
      The smallest Mygalomorph has a bodylength of just under one mm which is outright diminutive compared to the largest, the Goliath Birdeater, Theraphosa blondi, which can achieve a bodylength of 130 mm and a legspan of just under 300 mm.   Most of the Mygalorphs are medium-sized to very large, robustly built with large bodies and shortish to very short thick legs. Brown and black are the most common colours but there are more than a few that disply flashes of bright colours such as yellow, orange, red, and even purple and metallic blue or green. Many of the larger species, particularly the Tarantulas are so hairy as to be almost like they are covered in fur.   They all have prominent chelicerae - containing the poison glands - with large fangs which they may raise upwards, usually with raising the front legs as well, in defense when they feel threatened.  Mygalomorphs have two pairs of booklungs, and commonly no more than two pairs of spinnerets from which they can spin a lightly adhesive silk. Trapdoor Spiders use  the silk to line their tunnels while other Mygalomorphs can produce very large elaborate webs to catch their prey with.
      The oldest Mygalomorph fossils found to date are fossils of the Family: Hexathelidae and date back upto 247 My to the Early Triassic.  Dipluridae fossils from the Late Triassic, upto 228 Mya, come in as a close second.  Both families are Funnel-web Tarantulas and still exist today. Younger fossils of other families still extant have been unearthed as well.  The spread of the numerous fossil locations suggests that Mygalomorphs may already been widespread in the super-continent of Pangea prior to its' break-up.
Superfamily:   Avicularioidea
      Despite their impressive size and often fearsome appearance, the Mygalomorph spiders are not usually dangerous to humans.  They are rather placid in their behaviour and because of that, plus, their longevity, they are often kept as pets, particularly some of the larger Tarantulas.   There are exceptions though;  the Australian Funnel Web Spiders are not only aggressive at times, their bite can cause serious health issues.   There have been reports that the manual handling of certain species of Tarantula commonly used as pets may have been the cause of serious eye problems.  The Tarantula may have a certain type of body hair that once transferred to the eye can cause significant, long-term eye disease.  When handling any spiders with the bare hands, do not, at any time, rub the eyes and wash the hands thoroughly afterwards.
References  and  links:
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>      Blaikie, A.J., Ellis, J.,  Sanders, R.  and  MacEwen, C.J.,  (1997).    'Eye disease associated with handling pet tarantulas: three case reports.'   BMJ. 314 (7093): 1524–5.  doi:10.1136/bmj.314.7093.1524. PMC 2126783. PMID 9183200.
>      Coddington, J.A.   and  Levi, H.W.,  (1991).   'Systematics and evolution of spiders (Araneae).'   Annual Review of Ecology and Systematics. 22: 565–592.   doi:10.1146/annurev.es.22.110191.003025.
>      Dunlop, J.A.,  Penney D.  et al,  (2013).   'A summary list of fossil spiders and their relatives.'  The World Spider Catalog, version 14.0. American Museum of Natural History
>      Selden, P.A., da Costa Casado, F.   and  Mesquita, M.V.,  (2005).   'Mygalomorph spiders (Araneae: Dipluridae) from the Lower Cretaceous Crato Lagerstätte, Araripe Basin, north-east Brazil.'   Palaeontology. 49 (4): 817–826. doi:10.1111/j.1475-4983.2006.00561.x. 

>      https://www.earth.com/earthpedia-articles/supercontinents-101-pannotia-gondwana-and-pangea/​
​>      https://en.wikipedia.org/wiki/Goliath_birdeater​
​>      https://en.wikipedia.org/wiki/Mygalomorphae
>      https://www.mindat.org/taxon-P376960.html
>      https://wsc.nmbe.ch/statistics/
>      https://www.abc.net.au/news/2018-04-28/worlds-oldest-spider-dies-aged-43-in-western-australia/9707422

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