Missulena bradleyi, also known as the Eastern Mouse Spider, is a species of spider belonging to the family Actinopodidae. The spider is endemic to the east coast of Australia.
William Joseph Rainbow described the Eastern Mouse Spider in 1914, from a specimen collected in North Sydney by Henry Horton Burton Bradley (1845–1918), president of the Board of Trustees of the Australian Museum at the time. Describing the "beautiful and strikingly marked" specimen as a "decided novelty", Rainbow named it in honour of its collector, whom he stated was the first collector of Australian spiders.
Eastern Mouse Spiders are often mistaken for Australian Funnel-web Spiders. The females are large and very strong, with powerful chelicerae. Their fangs often cross over slightly while those of Australian Funnel-web Spiders remain parallel, and the latter often have a drop of venom on their fang tips and have longer spinnerets.
The Male Eastern Mouse Spider, which has an all-black carapace and a pale bluish area on top of the abdomen, roams around in autumn and early winter looking for a mate. They sometimes fall into swimming pools when wandering. Cases of envenomations have peaked during this period.
The burrow can be found by brushing away loose dirt in an area where they live until a flap of silk indicative of the entrance is found.
Common symptoms of Eastern Mouse Spiders bites are numbness and tingling at the bite site, as well as sweating (diaphoresis), headache and nausea generally. Although it appears to be the most dangerous member of the genus, serious envenomings by this species are relatively rare. Most bites documented in the medical literature did not require use of antivenom or involve serious symptoms. The venom of the Eastern Mouse Spiders has been found to have toxins similar to the robustoxin found in funnel-web venom; and funnel-web antivenom has been found to be effective in treating severe mouse spider bites. Compared to the Australian Funnel-web Spider, however, the Eastern Mouse Spider is far less aggressive towards humans, and may often give "dry" bites.