Basibulbus, a hard-bodied, haplogyne spider genus from Chile (Araneae, Dysderoidea). (American Museum novitates, no. 3775)
American Museum of Natural History.
A new genus, Basibulbus, is established to contain some seldom-collected, hard-bodied, haplogyne spiders from Chile. Because of their small size and the heavily scutate abdomen of males, these animals resemble gamasomorphine goblin spiders (Oonopidae), but differ in having a heavily sclerotized sperm duct within the male palp and a normal sperm opening in the epigastric furrow. Their tarsal organs lack both the longitudinal ridge and the serial dimorphism in raised receptor number that are considered synapomorphic for oonopids, but are elevated (albeit only at their proximal end), and the genus is therefore assigned to the Orsolobidae. Three new species are described: B. malleco (the type species) and B. concepcion from central Chile (regions VIII and IX), and B. granizo from further north (Region V). Only one other hard-bodied orsolobid genus has been described (Duripelta Forster from New Zealand); Basibulbus does not seem to be closely related to that genus, and represents another in the long list of relictual, phylogenetically significant, Chilean spider taxa. One of the possible synapomorphies of dysderoids, an oblique unsclerotized strip on the base of the anterior lateral spinnerets (which has been lost in higher gamasomorphines) has apparently been lost independently within Basibulbus. That character is present in B. granizo but absent in at least B. malleco.
20 pages : illustrations, some in color ; 26 cm
Basibulbus., Spiders., Chile.