Flat-tailed  and  Bark  Scorpions  -  Superfamily:  Buthoidea
      Until recently the Buthoidea contained two families but in 2022 the  Microcharmidae was found to be synonymous with Buthidae and so the former family was removed and the two genera and seventeen species therein are now placed within the Buthidae. (see previous page.)
So, a single family, the Buthidae, remains and it contains nearly half* of all scorpions presently known which on the 7th of March 2024 stood at 100 extant genera with 1,369 species.  The 'Australian Faunal Directory' lists eleven species of this family as occurring in Australia.  This is less than one per cent of all species in this family.  This paucity of diversity might be explained by the fact that Gondwanaland broke up well before the Buthidae appeared on the scene.  Australia separated from Gondwana some 99 My ago and the oldest fossils of buthid scorpions found to date are from the Eocene, a mere 50.3 My ago.
      The Buthidae are also known as Arrowbreasted Scorpions due to the sternum plate in most species being triangular​.  Many are small to medium sized scorpions ranging in length from 20 to 50 mm. but there are more than a few bigger ones  with some the largest species reaching 120 mm. in length.  Colours vary but the earthy tones like ochres and browns are most common but they can be any colour or combination of colours between cream and black. There are also quite a few species with attractive patterns.  Immediately after ecdysis  (= moulting) scorpions are very pale but the original colours from before the moult will return before too long. Interestingly, scorpions appear bright blue under black light (= ultraviolet) and this may help finding them at night when they are most active.    
      There are about 25 or so species of scorpions (or just under 1% of all species) that are deadly even to humans and most of these are from the Family: Buthidae.  There are many others that are dangerously venomous but not lethal.  Most however, are capable of inflicting no more than a painful sting with only a localised reaction such as ongoing pain and swelling.  In Australia, there are no dangerous scorpions.  That is not to say that scorpions found in Australia are to be treated with nonchalance; a painful sting is likely to result and of course, an allergic reaction is always possible. 
​      
*  =  Various authors have attempted to separate the Buthidae into subfamilies based on various features or even geographical distribution however, none of these divisions proved to be reliable enough.  It is now widely accepted that the attempts were futile and that the Buthidae are indeed one very large yet, cohesive family.

Family:  Buthidae

      Hemilychas alexandrinus     (possible occurrence)
      
      Lesser Brown Scorpion  -  Isometrus maculatus
      Little Marbled Scorpion  -  Lychas marmoreus

      
      Marbled Scorpion  -  Lychas variatus
      Reddyanus melanodactylus

Taxonomy:
​​​​​​​​
Phylum:   Arthropoda   (Arthropods)
          > Subphylum:   Chelicerata   (Chelicerates)
                    > Class:   Arachnida   (Arachnids)  
                                        > Order:   Scorpiones   (Scorpions)
                                                  > Suborder:   Neoscorpionina
                                                            > Infraorder:   Orthosterni
                                                                 > Parvorder:   Buthida
                                                                      > Superfamily:   Buthoidea   (Flat-tailed,-   Bark Scorpions and Allies)
                                                                                > Family:   Buthidae   (Arrowbreasted Scorpions)
                                                                                                              > Genus:   Hemilychas
                                                                                                                        > Species:   H. alexandrinus  ^
                                                                                                              > Genus:   Isometrus
                                                                                                                        > Species:   I. maculatus - Lesser Brown Scorpion
                                                                                                              > Genus:   Lychas   (Forest Thick-tailed Scorpions)
                                                                                                                        > Species:   L. marmoreus - Little Marbled Scorpion
                                                                                                                        > Species:   L. variatus - Marbled Scorpion
​                                                                                                              > Genus:   Reddyanus
                                                                                                                        > Species:   R. melanodactylus
​

*  =  likely
^  =  possibly
References  and  links:
​
>      Fet, V.,  Sissom, W.D.,  Lowe, G.  and  Braunwalder, M.E..  (2000).   'Catalog of the Scorpions of the World (1758-1998).'  New York Entomological Society, 2000.

      https://biodiversity.org.au/afd/taxa/SCORPIONES/checklist​
      https://en.wikipedia.org/wiki/Ecdysis​
      https://inaturalist.ala.org.au/observations/3902604
      https://www.mindat.org/taxon-5848.html
      https://www.ntnu.no/ub/scorpion-files/akravidae.php
      https://www.ntnu.no/ub/scorpion-files/buthidae.php

Photographic  Contributions:

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