Plebs eburnus

Plebs eburnus
Female P.eburnus on web.
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Arachnida
Order:	Araneae
Suborder:	Araneomorphae
Family:	Araneidae
Genus:	Plebs
Species:	P. eburnus
Binomial name
Plebs eburnus Keyserling, 1886 [1]
Synonyms
Epeira eburna, Keyserling 1886[2] Araneus eburnus, Rainbow 1911[2] Araneus eburneus, Simon 1895[2] Epeira rubripunctata, Rainbow 1893[2] Epeira sinuosus, Rainbow 1893[2] Aranea eburnea, Roewer 1942[2] Aranea rubripunctata, Roewer 1942[2] Aranea sinuosa, Roewer 1942[2] Araneus rubripunctatus, Bonnet 1955[2]

The spider species Plebs eburnus is commonly referred to as the Eastern Grass Orb-weaver or the Eastern Bush Orb-weaver, and sometimes more simply the Bush Orb-weaver. It is an orb-weaver spider from the Araneidae family, it is endemic to Australia. It was previously classified as a member of the genus Araneus but has been reclassified in 2012 ^[3] into a newly described genus Plebs.^[2] It is closely related to the Western Bush Orb-weaver, P. cyphoxis. It is a very common spider with distinctive white markings (although these marking can be quite variable), which give it the species name eburnus pertaining to ivory. It is found in scrub and tall grasses where the female constructs a vertical web usually no more than 2 metres from the ground, and stays there day and night. The web of some of these spiders has been seen to be decorated with nearly vertical stabilimentum (like a clockface at 5 minutes to 5 or its mirror image).^[4] The stabilimentum of P.cyphoxis is usually observed vertical (like a clockface at 6 o'clock).^[5]

Distribution

Approximate range of P. eburnus created from field record locations in Joseph & Framenau 2012.^[2]

P. eburnus can be found in Queensland, New South Wales, Victoria, Tasmania, Australian Capital Territory and South Australia. Some rare occurrences have been observed in Western Australia although this is not part of the typical range of this species.^[6] The ranges of this species and P. cyphoxis overlap in South Australia.^[2]

Size and markings

On the underside of the abdomen, along with other members of the Plebs genus, there is a characteristic U-shaped white marking with two white spots either side of the spinnerets.^[2] The females, as with most spiders, are larger than the males and are around 8mm in length, compared to just 5mm in length for the males.

References