Sericopelma angustum, commonly known as the Costa Rican Red-rump Tarantula, is a terrestrial species of spider within the family Theraphosidae. Native primarily to Costa Rica, it was originally described in 1980 and was long classified under the genus Brachypelma before being moved to Sericopelma in 2015. 
 
Taxonomy and Hobby Confusion
There is significant confusion regarding this species in the exotic pet trade:
Misidentification: Many tarantulas sold in the hobby since the early 1990s as "Brachypelma angustum" or "Sericopelma angustum" are considered misidentified and do not match the original scientific description.
Genetic Shift: Hobby specimens often resemble the Tliltocatl genus (like Tliltocatl vagans). Genuine Sericopelma spiderlings typically have blueish bodies with white bands on their legs, a feature lacking in most "hobby angustum". 
 
Physical Characteristics
Size: Adult females typically reach a body length of approximately 6 cm (2.4 inches).
Appearance: They are generally black or dark brown with long, wavy reddish hairs covering the abdomen and posterior legs.
Defence: They possess both Type I and Type III urticating hairs. 
 
Care and Behaviour
Temperament: While often described as relatively docile and a good display species, some accounts note they can be territorial and quick to bite if disturbed.
Habitat: An opportunistic burrower, it requires a substrate depth of at least 3–4 inches to allow for tunnelling.
Environment: They thrive at temperatures between 70°F–85°F (21°C–29°C) and humidity levels of 65%–80%.
Diet: They are excellent eaters, consuming a variety of insects such as crickets and roaches.