Taxonomy

Megaloastia has one Australian species, Megaloastia mainae. The genus is part of an Australasian clade (Maddison et al 2008) including Adoxotoma, Arasia, Astia, Astilodes, Helpis, Jacksonoides, Parahelpis, Sondra and Tauala. Genera from Indonesia (Katya) and the Philippines (Orthrus) may also be part of this group (Maddison 2015). Further information on the genus and described species can be found in Richardson and Żabka (2017).

Description

Megaloastia mainae is a medium to large-sized spider, body length 5 to 15 mm, with an elongated-ovate, tapering abdomen. The head, viewed from above, is rounded or pear-shaped with the widest point behind the posterior lateral eyes. The high cephalothorax has posterior lateral eyes on distinct peaks. Chelicerae have many (plurident) retromarginal teeth and three or more promarginal teeth on a mound. The legs are extremely long, spread laterally and armed with long spines. The first legs are longest (up to four times the length of the body). The other legs are also very long and of approximately equal length.

The male’s palpal tibia has a single, short, hooked, pointed retro-lateral tibial apophysis. The tegulum is rounded, with a small proximal ledge. A short, thick embolus arises in the middle of the tegulum and has a twisted end.

Females have an epigynal atrium partly divided in two, with lateral sclerotised guides. The copulatory openings are on the antero-lateral edges of the atrium. The insemination ducts are long, joining the anterior edge of the spermathecae. The spermathecae are cup-shaped and lie behind the atria, close to the epigastric fold.

References

Gardzińska, J. & Żabka, M. 2010. A new genus and five new species of Astieae (Araneae: Salticidae) from Australia, with remarks on distribution. Zootaxa 2526: 37-53.

Maddison, W.P. 2015. A phylogenetic classification of jumping spiders (Araneae: Salticidae). Journal of Arachnology 43, 231-292.

Maddison, W.P., Bodner, M.R. & Needham, K.M. 2008. Salticid spider phylogeny revisited, with the discovery of a large Australian clade (Araneae: Salticidae). Zootaxa 1893, 49-64.

Richardson, B.J. & Żabka, M. 2016. Salticidae. Arachnida: Araneomorphae. Canberra, Australian Faunal Directory. Australian Biological Resources Study, at https://biodiversity.org.au/afd/taxa/SALTICIDAE.

Soley, F.G., McGinley, R.H. Collins, S.R. & Taylor, P.W. 2016. Natural History observation and predatory behavior of a long-legged jumping spider, Megaloastia mainae (Aranaea: Salticidae). New Zealand Journal of Zoology 43, 65-84.

Zabka, M. 1995. Salticidae (Arachnida: Araneae) of Oriental, Australian and Pacific Regions, XI. A new genus of Astieae from Western Australia. Records of the Western Australian Museum, Supplement 52, 159-164.

* The information sheet should be interpreted in the context of the associated diagrams and photographs. Diagrams explaining anatomical terms can be found in the ‘Salticidae’ pictures at the beginning of the list of genera.