Hidden beneath the gnarled bark of eucalypt trees in Southern Australia were two cryptic tube web spiders initially discovered by Jess Marsh, who conducted a study on the effects of fire on spider communities on Kangaroo Island. Harry Butler Institute’s own resident spider expert Dr Volker Framenau was consulted for the scientific description of these species, which are now known as Ariadna clavata and Ariadna tangara, bringing the count of Australian tube web spider species from 15 to 17.

Dr. Framenau was also part of the team to discover the purpose of A. tangara’s unique front legs.  By observing spiders in their native mallee woodland habitat, Jess witnessed male A. tangara using the apophyses and spines on their front legs to vibrate the entrance to the female’s web in courtship.  If the males got lucky, they were also able to use their legs to secure themselves during mating, allowing the female to remain in the safety of her home.

The rigor of the research team, that also included Barbara Baehr (Queensland Museum) and Richard Glatz (D’Estrees Entomology & Sciences Services), also yielded precise descriptions of both species that included morphological characters not previously considered in their taxonomy.  Future researchers can now rely on well-preserved samples of verified adult males and females of both species.  What elevated their precision was the dissection of multiple female spiders to confirm sexual maturity.  This diligence also allowed for further
certainty of identification, as the internal organs of females varied significantly between species.

Research like this is vital to understanding and protecting Australia’s unique biodiversity.  If you are interested in the fine detail of spider taxonomy, we recommend the team’s recently published paper in the journal Evolutionary Systematics.  It includes much more detail of the physical characteristics of these two new spiders. Arachnophobes beware.

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