ThomisidaeRuncinia acuminata Sidymella Thomisidae Image Index Tharrhalea sp Tharrhalea evanida Tharrhalea multopunctata Thomisus spectabilis Tmarus cinerasceus Xysticus bimaculatus Zygometis xanthogaster

The genus Sidymella, commonly known as the Square-ended Crab Spiders, belong to the family Thomisidae, and can be found in South America, Australia and New Zealand. In Australia, the species population are found along the east and south coast of Australia, from Far Northern Queensland down to and including Tasmania. There are scattered species populations heading inland, with just a handful of documented sightings in Central Australia, and top end to Western Australia.1

The commonly known Fork-tailed and Awl-tailed Sidymella are widespread in New South Wales and South East Queensland, from rainforest to arid areas. It has relatively flat cephalothorax, a long, raised and sometimes double-pointed end to its abdomen and the front two sets of legs are exceptionally long and usually held outstretched.

Fork-tailed Sidymella Spider (genus Sidymella), Brisbane QLD © Stefan Jones
Fork-tailed Sidymella Spider (genus Sidymella), Brisbane QLD © Stefan Jones

The following undescribed species, are different in that the grey-coloured Sidymella has prominent black spot on either side of the bifurcated tail (bifurcated tail refers to the appearance of the division in the flexible elongated appendage located at the end of the torso).

The Sidymella longipes is a medium to large crab spider with long legs. A pale, semi-transparent spider they are often seen resting along a twig, with its first two pairs of legs pointing forward.

It is widely distributed on Australia’s east coast, from Cairns, Sydney, Melbourne, Geraldton, and Tasmania. Also common on New Zealand’s north Island.

Long-legged Crab Spider (Sidymella longipes), Brisbane QLD © Stefan Jones
Long-legged Crab Spider (Sidymella longipes), Brisbane QLD © Stefan Jones

There were 21 species listed (at the time of writing) in Atlas of Living Australia, with 8 of the species here in Australia including: Sidymella bicuspidata, Sidymella hirsuta, Sidymella kochi, Sidymella lampei, Sidymella lobata, Sidymella longipes, Sidymella rubrosignata and Sidymella trapezia.


  • Scientific classification
  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Subphylum: Chelicerata
  • Class: Arachnida
  • Order: Araneae
  • Suborder: Araneomorphae
  • Infraorder: Entelegynae
  • Superfamily: Thomisoidea
  • Family: Thomisidae
  • Genus: Sidymella
  • Species:
    • Sidymella angularis (Urquhart, 1885)
    • Sidymella angulata (Urquhart, 1885)
    • Sidymella benhami (Hogg, 1910)
    • Sidymella bicuspidata (L. Koch, 1874)
    • Sidymella hirsuta (L. Koch, 1874)
    • Sidymella jordanensis (Soares, 1944)
    • Sidymella kochi (Simon, 1908)
    • Sidymella kolpogaster (Lise, 1973)
    • Sidymella lampei (Strand, 1913)
    • Sidymella lobata (L. Koch, 1874)
    • Sidymella longipes (L. Koch, 1874)
    • Sidymella longispina (Mello-Leitão, 1943)
    • Sidymella lucida (Keyserling, 1880) (type species)
    • Sidymella multispinulosa (Mello-Leitão, 1944)
    • Sidymella nigripes (Mello-Leitão, 1947)
    • Sidymella obscura (Mello-Leitão, 1929)
    • Sidymella parallela (Mello-Leitão, 1929)
    • Sidymella rubrosignata (L. Koch, 1874)
    • Sidymella sigillata (Mello-Leitão, 1941)
    • Sidymella spinifera (Mello-Leitão, 1929)
    • Sidymella trapezia (L. Koch, 1874)

      there are currently 21 species listed.

Footnote & References

  1. Sidymella Strand, 1942, Atlas of Living Australia, https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/0bb3ba6a-b582-4262-bcee-7c61bade4397
  2. Square-ended Crab Spiders (Genus Sidymella), iNaturalistAU, https://inaturalist.ala.org.au/taxa/202191-Sidymella
  3. Sidymella longipes (L. Koch, 1874) Longlegged Sidymella, Arachne.org.au, http://www.arachne.org.au/01_cms/details.asp?ID=2222 (this site is no longer active. Some content can be viewed on Wayback Machine)
  4. Photographs Sidymella © Stefan Jones
  5. Many thanks for help with ID from Micky O’Brien, Annette Fraser-Dunn and members of the Australian spider identification page, https://www.facebook.com/groups/australianspidereducation

ThomisidaeRuncinia acuminata Sidymella Thomisidae Image Index Tharrhalea sp Tharrhalea evanida Tharrhalea multopunctata Thomisus spectabilis Tmarus cinerasceus Xysticus bimaculatus Zygometis xanthogaster

SpidersIndex of Spider Images Spiders in Australia Spiders Index Araneidae — Orb Weavers Arkys Australian Huntsman Spider Barking Spider Black House Spider Carepalxis sp Celaenia sp Crab Spiders Deinopidae — Net-casting Spiders Dolomedes sp Dolophones sp Euryopis umbilicate (Superb Ant-eater Spider) Flower Spiders Hackled Orbweavers (Uloboridae) Herennia sp Jewel Spider Jumping Spider Long Jawed Spider (Tetragnatha sp) Lynx Spider (Oxyopes) Mangrovia albida Maratus Missulena occatoria (Red-headed Mouse Spider) Miturgidae Nicodamidae (Red and Black Spider) Nyssus coloripes (Orange-legged Swift Spider) Ogre-faced Net-casting Spider Poltys sp (Twig Spider) Redback Spider Scorpion-tailed Spider (Arachnura higginsi) Thomisidae Wolf Spider Tiger Spider (Trichonephila plumipes) White-spotted Swift Spider (Nyssus albopunctatus)