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Venomous Pseudoscorpions - Suborder: Iocheirata
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The 'venomous'* pseudoscorpions belong to the Suborder: Iocheirata - meaning 'poison hands'. This suborder encompasses about three quarters of all known species of pseudoscorpions and is itself subdivided into two infraorders. One of these, the Hemictenata, was until recently known only from certain parts of the Northern Hemisphere. (a new cave-dwelling species from Brazil was described by de Andrade and Mahnert in 2003.) The other, the Panctenata, is an infraorder with a much more cospmopolitan distribution and is found on all continents excluding Antarctica. Only the Panctenata are dealt with on these pages.
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Whereas most common in the more temperate climates, species from the Infraorder: Panctenata are also quite plentiful in the tropics. Furthermore, there are even species recorded from the northern parts of Alaska and the southernmost parts of South America.
In keeping with M.S. Harvey's (1992) rearrangement of the pseudoscorpions, the Panctenata here too, are sub-divided into two. These divisions - zoosections, referred to by Harvey as microorders - are both represented in Australia. Worldwide, the Zoosection: Elassommatina are the more widespread whereas the Mestommatina seem to be restricted to the warmer parts of the world. |
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The diagnoses that separate the various subdivisions proposed by Harvey (1992) relate to various morphological features that the individual groups share. These features are usually not obvious at first glance and most commonly require a microscope to observe. For instance, the Hemictenata are diagnosed solely by the presence of tooth-like structures on the setae - hairs or bristles - on the subterminal tarsus or leg segment. The Panctenata on the other hand, are diagnosed by a number of features some of which relate to the 'finger' of the chelicerae, among others.
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Infraorder: Panctenata
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* = The Iocheirata are unique among Chelicerata in that they possess a venom apparatus that terminates in the moveable finger of the chelicerae. However, in some groups of the Iocheirata this particular feature has been lost from either one of the chelicerae during the course of evolution. One iocheirid species, Myrmochernes africanus, does not have a venom apparatus at all but, other than that, its relationships with other member species of the Family: Chernetidae is so obvious that the loss of the venom apparatus is considered secondary.
References and links:
> Andrade, R. de, and Mahnert, V., (2003). 'Spelaeobochica muchmorei sp. n., a new cavernicolous pseudoscorpion (Pseudoscorpiones: Bochicidae) from Brazil (São Paulo State).'
Revue Suisse de Zoologie, 110, 541-546
> Harvey, M.S., (1992). 'The phylogeny and classification of the Pseudoscorpionida (Chelicerata: Arachnida).' Invertebrate Taxonomy. 6. 1373–1435. DOI:10.1071/IT9921373.
https://biodiversity.org.au/afd/taxa/IOCHEIRATA
https://www.catalogueoflife.org/data/taxon/4DY
https://inaturalist.ala.org.au/taxa/928851-Elassommatina
https://inaturalist.ala.org.au/taxa/928860-Mestommatina
> Andrade, R. de, and Mahnert, V., (2003). 'Spelaeobochica muchmorei sp. n., a new cavernicolous pseudoscorpion (Pseudoscorpiones: Bochicidae) from Brazil (São Paulo State).'
Revue Suisse de Zoologie, 110, 541-546
> Harvey, M.S., (1992). 'The phylogeny and classification of the Pseudoscorpionida (Chelicerata: Arachnida).' Invertebrate Taxonomy. 6. 1373–1435. DOI:10.1071/IT9921373.
https://biodiversity.org.au/afd/taxa/IOCHEIRATA
https://www.catalogueoflife.org/data/taxon/4DY
https://inaturalist.ala.org.au/taxa/928851-Elassommatina
https://inaturalist.ala.org.au/taxa/928860-Mestommatina
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