Can-opener Marine Spider
This intertidal spider may be distinguished from Desis of similar habitat by its elongated posterior lateral spinnerets. Twice the length of the anterior lateral spinnerets, they extend well beyond the abdomen, allowing the species to be recognised readily along some of our beaches. Like Desis, the fangs are well developed, but the chelicerae are shorter and stouter than those of Desis. They are also distally divergent, meaning spread out at the end furthest from the cephalothorax. The male palps of P. armata are literally armed with an appendage on the palpal tibia that looks like a can-opener. It has a short blunt "ledge" at one end and a prominent spur at the opposing end.
| Length | ♀ 3 – 5 mm; ♂ 3 – 4 mm |
| Type Locality | Swains Island, American Samoa |
| Distribution | Widespread, including Singapore, Micronesia, American Samoa. |
| Habitat | Coral rubble, shells of dead barnacles and other encrustations in the intertidal zone. |
| Biology | It constructs a small funnel-like silk retreat that is submerged at high tide. During low tide, it emerges from the retreat and roams about in search for prey. |
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Chelicerata (Chelicerates)
Class Arachnida (Arachnids)
Order Araneae (Spiders)
Suborder Araneomorphae (Typical Spiders)
Swainsia armata (Original description ♂)
Marples, 1964 Spiders from some Pacific islands, part V: 403, f. 2
Swainsia armata (♂)
Lehtinen, 1967 Classification of the cribellate spiders and some allied families, with notes on the evolution of the suborder Araneomorpha: 450, f. 269-270
Paratheuma armata (♂, D♀)
Beatty & Berry, 1988 The spider genus Paratheuma (Araneae, Desidae): 51, f. 3, 6, 9
Paratheuma armata (♂♀)
Crews et al., 2020 The life aquatic with spiders (Araneae): repeated evolution of aquatic habitat association in Dictynidae and allied taxa: 908, f. 16C-G, S14G doi:10.1093/zoolinnean/zlz139
* Retrieved from the World Spider Catalog.
Widespread, including Singapore, Micronesia, American Samoa.