Subject: Any Idea?
Location: Sydney, NSW, Australia
August 2, 2014 5:13 am
I found this 2cm big guy near a salt water river in Sydney, Australia. I have no clue if its a spider/scorpion thing or just a bug or whatever. I am not even sure if there a 4, 6 or 8 legs …
I googled a lot but cant find anything helpful…
(sorry for my english 😉 )
Signature: Ben

Crab Spider:  Sidymella species

Crab Spider: Sidymella species

Dear Ben,
Your English is perfectly fine.  Your confusion is well founded.  Both Spiders and Scorpions are classified in the zoological class Arachnida, the Arachnids, so they share many physical similarities.  Insects and Arachnids, including Spider and Scorpions, are classified together in the phylum Arthropoda, and again, they all share certain physical characteristics.  With that stated, this is a Spider in the order Araneae, and Spiders are identified because they have two body parts, the cephalothorax (combined head and thorax) and abdomen, and eight legs.  This particular Spider is holding its two front pairs of legs together, which makes it a bit difficult to count.  The two front pairs of legs are considerably longer than the rear two pairs, and this is a physical trait shared by Crab Spiders in the family Thomisidae.  Once we got to that level of identification, we turned to one of our favorite sites for identifying Australian Arthropods, the Brisbane Insects and Spiders, where we found a very similar looking Crab Spider identified as being in one of two genera:
Tmarus or Sidymella.  The site author coined the name Peak Crab Spider ” because its abdomen rises to a dorsal peak.  Its two front pairs of legs are much longer than the hind two pairs.”  Scroll to the bottom of the page to see the Peak Crab Spider.  Armed with that information, we found other representatives in the genus pictured on Spiders of Australia, and the closest matches are not yet fully identified, and are given the names Sidymella ZZ477 and Sidymella ZZ592.  Those letter and number identifyers indicate that the Spiders have yet to be described in a published paper at which time they can be given species names by the describer.  This is a very exciting posting for us and we are featuring it in our scrolling featured posting bar.

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Location: Sydney, Australia

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