The Florida false wolf spider, Ctenus captiosus

Among the larger spiders that can occur in homes in peninsular Florida is Ctenus captiosus Gertsch. Superficially, C. captiosus is similar in size and appearance to the sympatric wolf spider Gladicosa pulchra (Keyserling) (Brady 1986), and is almost always mistaken for a wolf spider (family Lycosidae). Although it looks like a wolf spider, C. captiosus actually belongs to the family Ctenidae. Ctenids can be determined to family by their unique eye arrangement, 8 eyes in 3 rows in a 2-4-2 pattern (fig. 1). Lycosids also have a unique pattern, but in a 4-2- 2 arrangement (fig. 2). Kaston (1978) listed “running spiders” as a common name for ctenids. They are fast runners, but so are numerous other spiders. Their size, appearance and habits, as well as the fact that they are related to (Homann 1961) and often mistaken for wolf spiders, would seem to make “false wolf spiders” a much more appropriate common name for them.

Ctenus captiosus is one of only 2 species of Ctenidae occurring in Florida. The second species is Anahita punctulata (Hentz), a smaller species found primarily in the Florida panhandle and in other southeastern states. Only Florida localities so far have been reported for C. captiosus, although it likely occurs in southern Georgia as well. These records range the entire length of peninsular Florida, excepting the Keys.

The family Ctenidae is primarily tropical and worldwide in distribution. Some species of the genera Cupiennius and Phoneutria are among the largest non-tarantula spiders known. Phoneutriafera Perty of Brasil is known to be dangerous to humans, but rarely causes death (Bucherl 1956). Nothing is known of the bite of C. captiosus, but based on its size and knowledge of its relatives, one might expect some pain and perhaps swelling to be associated with the bite. As with any spider bite, all severe or allergic reactions to a bite should receive prompt medical attention.