Researchers led by Dr. Alireza Zamani of the University of Turku have identified four previously unknown tarantula species in the Arabian Peninsula and the Horn of Africa. These spiders are so distinct that they required a new genus, Satyrex, named after a mythological figure and Latin for king. Males feature the longest palps recorded in tarantulas, possibly to safely mate with aggressive females.
Dr. Zamani's team established the genus Satyrex based on morphological and molecular data, setting it apart from closest relatives. The name combines Satyr, known for exaggerated anatomy, with rēx, meaning king. Satyrex ferox, the largest species, reaches a legspan of 14 cm, with male palps up to 5 cm long—nearly four times the front body section and almost as long as the legs. Dr. Zamani noted, 'The males of these spiders have the longest palps among all known tarantulas.' Palps transfer sperm during mating. The team suggests these elongated palps allow males to maintain distance from females, avoiding attack or cannibalism. Satyrex ferox lives up to its name, meaning fierce. At disturbances, it raises front legs in threat and hisses by rubbing specialized hairs. Dr. Zamani explained, 'This species is highly defensive... produces a loud hissing sound.' The new species are S. arabicus, S. somalicus—named for their regions—and S. speciosus, for its vivid colors. The genus includes S. longimanus, first described in Yemen in 1903 and reclassified from Monocentropus due to its unusually long palps. All Satyrex tarantulas are fossorial, burrowing under shrubs or rocks. The study appeared in the open-access journal ZooKeys.