Scientists have identified a new genus of tarantula, named Satyrex, characterised by males possessing remarkably elongated genitalia. The spiders inhabit the Arabian Peninsula and the Horn of Africa, with four new species described in a recent study.
The largest species, Satyrex ferox, boasts a leg span of around 14 cm, but its palps – specialised appendages used for sperm transfer – can reach an incredible 5 cm in length. This is nearly four times the length of the front part of its body and almost as long as its longest legs.
The spiders are highly aggressive, and researchers believe the oversized palps may have evolved to help males avoid being eaten by females during mating. Dr Alireza Zamani of the University of Turku, who led the study, said: 'The males of these spiders have the longest palps among all known tarantulas.'
The genus name Satyrex combines 'Satyr', a figure from Greek mythology known for large genitalia, and the Latin word 'rēx', meaning king. The species S. ferox was named for its fierce defensive behaviour, while others were named for their regions or colouration. An older species, S. longimanus, originally described from Yemen in 1903, was also reclassified into the new genus.
All members of the genus are fossorial, living underground in burrows. The study, published in the open-access journal ZooKeys, highlights the distinct morphological and molecular differences that warranted the establishment of a new genus.
