About Pachistopelma rufonigrum Pocock, 1901
This species of tarantula can be distinguished from Pachistopelma bromelicola by its slender fourth metatarsus, which lacks stiff bristles, and by its pink legs with black tarsi. Juveniles are almost entirely metallic green, aside from a pattern on the dorsal surface of the abdomen. This pattern consists of a central longitudinal black stripe connected to five lateral black stripes. In larger juvenile individuals, the border of the carapace and the dorsal surfaces of the chelicerae, coxae, and trochantera are light brown. The dorsal abdomen is light brown with a reddish area in the posterior section, and the black stripes from the juvenile pattern are still visible. In the next growth stage, the entire carapace is pink, as are the dorsal surfaces of the coxae, trochantera, and most femora. The remaining sections of the legs keep their metallic green coloration. The unstriped area of the abdomen becomes a vivid red, while the black stripes remain visible. Subadults have brown carapaces and legs with sparse long pinkish hairs. The dorsal abdomen is still reddish, but the black stripes begin to fade. The adult female is completely brown, with long pinkish setae covering the legs, carapace, and chelicerae. The abdominal stripe pattern is either absent or very faint. The adult male has brown carapace, chelicerae, and legs covered in pinkish setae, except for the black tarsi and a black stripe on the metatarsi. Its abdomen is a vivid orange-red, with no trace of the striped juvenile pattern.
