Eight-Spotted Crab Spider
The females of this species are amongst the world’s largest crab spiders. Its species name "octomaculatus" means "eight spots". Eight black spots were shown on the drawing of the original specimen described but mature females seen in Singapore, Brunei and East and West Malaysia possess only seven dorsal spots on the abdomen, with an eighth spot on its ventral side. Some juvenile females have only five spots on the dorsum. In mature females the number of spots on the carapace varies from four to six.
The males are smaller, with their colour varying from red to yellow. Their dorsum also shows seven spots, but only three are clearly visible, with the remaining four being small and inconspicuous.
A female P. octomaculatus overpowering a praying mantis twice its size. It has lost three of its legs, presumably in the struggle against an aggressive prey.
| Length | ♀ Up to 23 mm; ♂ 4–5 mm |
| Type Locality | "Ostindien", i.e. "East Indies", now Indonesia |
| Distribution | Singapore, Malaysia (Sabah, Johor), Indonesia (Java, Sumatra), Brunei. |
| Habitat | Foliage among low-lying vegetation in mangroves and disturbed wooded areas. |
| Biology | Females bind a wide leaf on top of another using extraordinarily strong white silk. They sit inside the enclosed space during the day and may emerge, sometimes hanging inverted under the lower leaf at night. They extend their first two pairs of legs in a raptorial pose, ready to seize prey when it arrives. They can overpower dangerous prey like a praying mantis. The egg sac is protected by the mother until the spiderlings emerge in about two weeks. |
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Chelicerata (Chelicerates)
Class Arachnida (Arachnids)
Order Araneae (Spiders)
Suborder Araneomorphae (Typical Spiders)
Thomisus 8-maculatus (Original description ♀)
C. L. Koch, 1845 Die Arachniden: 55, f. 990 doi:10.5962/bhl.title.43744
Platythomisus phryniformis (Original description ♀)
Doleschall, 1859 Tweede Bijdrage tot de kennis der Arachniden van den Indischen Archipel: 60, pl. 3, f. 10
Platythomisus octomaculatus (♀)
van Hasselt, 1882 Araneae: 42, pl. 3, f. 4 doi:10.5962/bhl.title.119451
Platythomisus octomaculatus (♀)
Simon, 1895a Histoire naturelle des araignées. Deuxième édition, tome premier: 1017, f. 1076 doi:10.5962/bhl.title.51973
Platythomisus octomaculatus (Original description ♂, ♀)
Lin et al., 2019b Description on two species of genus Platythomisus (Araneae, Thomisidae) from China and Singapore: 75, f. 1A-C, 2A,C, 3A-B, 4A-D, 5A-B doi:10.3897/zookeys.852.34436
* Retrieved from the World Spider Catalog.
Singapore, Malaysia (Sabah, Johor), Indonesia (Java, Sumatra), Brunei.