A thousand theraphosids stole a wolf spider’s name
Theraphosidae packs more than a thousand often-hairy spiders in nearly two hundred genera, yet the word tarantula began with Lycosa tarantula, a Mediterranean wolf spider named for Taranto. Today the label sticks to New World giants whose fangs stab downward, not pinching sideways.
Body lengths run about five to eleven centimetres with leg spans eight to thirty centimetres measured tip to opposite tip. Theraphosa blondi is usually called the heaviest; pinkfoot goliath T. apophysis, described 187 years later, claims the greatest span, while Lasiodora species also rival the giants. North American forms are mostly brown, but elsewhere cobalt Cyriopagopus, striped Aphonopelma, and metallic blue-legged showpieces dazzle pet keepers.
Like other arachnids they split into prosoma and opisthosoma linked by a pedicel, relying on an exoskeleton. Downward-facing fangs and two book lungs separate them from many “true spiders” with opposing fangs and a single book lung. Related mygalomorphs—trapdoors, funnel-webs, pursewebs—invite confusion, as do some wolf spiders; incorrect common names also cover atypical tarantulas and dwarf forms outside Theraphosidae.
Carl Ludwig Koch’s 1850 Eurypelma nodded to velvet footsole brushes, seeding many -pelma genus names from Acanthopelma to Brachypelma. Captive trade now keeps several species readily available. The Italian folk memory of tarantism clung to the wolf spider’s town name long after systematists redirected “tarantula” toward the hairy New World celebrities that fill terrariums and field guides.
Pet trade popularity has made several theraphosids terrarium staples, yet wild coloration still surprises: cobalt blues, orange-and-blue legs, and zebra striping far from the drab brown North American default. Distinguishing them from funnel-webs or wolf spiders still starts with fang orientation and book-lung count. Whether the Italian town’s wolf spider or a Venezuelan goliath fills the word, “tarantula” now signals size and hair more than a single evolutionary story—an everyday reminder that common names wander farther than taxonomists prefer.
Source: Tarantula
