''Pachistopelma rufonigrum'' is a species of theraphosid, contained within the

Aviculariinae The Aviculariinae are a subfamily of spiders in the family Theraphosidae (tarantulas). They can be distinguished from other theraphosids by a number of characters. Their legs have no or few spines on the underside (ventral surface) of the tibial ...

subfamily. It is endemic to

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Characteristic features

This tarantula differs from '' P. bromelicola'' by having a slender fourth

metatarsus The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the med ...

, without stiff bristles, and pink coloured legs with black tarsi. Juveniles are almost completely metallic green, except for a pattern on dorsum of abdomen comprising a central longitudinal black stripe connected with five lateral black stripes. In larger individuals

carapace A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...

border and dorsum of

chelicera The chelicerae () are the mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated fangs, or similarly ...

e, coxae and trochantera are light brown. Dorsum of abdomen is light brown with a reddish area posteriorly. The black stripes remain. In a next stage carapace is completely pink, as well as dorsum of coxae, trochantera and most

femora The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with t ...

. Remaining parts of legs retain the metallic green. The clear part of abdomen is now of a vivid red, and the black stripes remain. Subadults have carapace and legs brown with sparse pinkish long hairs. Dorsum of abdomen is still reddish, but the black stripes begin to fade. Adult female is completely brown with long pinkish

seta In biology, setae (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. Th ...

e on legs, carapace and chelicerae. Abdominal pattern is lacking or very inconspicuous. Adult male carapace, chelicerae and legs are brown and covered by pinkish setae, except for the tarsi and a stripe on metatarsi that are black. Abdomen is a vivid orange-red, there is no vestige of any pattern.

References

{{Taxonbar, from=Q2786676 Theraphosidae Spiders of Brazil Spiders described in 1901