Costa Rican Black / Red Rump Tarantula
Sericopelma angustum (likely)
Theraphosidae (Tarantulas), Order Araneae. Key characteristics include heavy bodies, significant hairiness, and two claws on each leg.
Physical Description
Large, robust mygalomorph with a thick cephalothorax and a bulbous abdomen. The body is covered in fine setae (hairs), and the chelicerae are large and downward-pointing.
Size Estimate
Estimated body length 2-3 inches; leg span 4-6 inches. This appears to be a sub-adult or adult specimen.
Coloration & Markings
Predominantly dark brown to black base color. Distinctive reddish or orange 'fire' hairs may be present on the abdomen (butt), though obscured by low light in the image. Brighter markings on the joints are possible.
Web Type
Terrestrial burrower; does not build typical catching webs. Instead, it lines a silk burrow or retreat for structural integrity and sensory detection.
Eye Arrangement
Small ocular tubercle located at the front-center of the cephalothorax, containing eight eyes in a tight cluster; typical of tarantulas that rely on vibration over vision.
Leg Characteristics
Thick, hairy, and powerful legs designed for digging and pouncing. Dense scopulae (sticky hair pads) on the feet allow for climbing smooth surfaces.
Venom & Safety Information
Venom Information
Possesses mild, protein-based venom intended for paralyzing prey. Not considered medically significant to healthy humans; comparable to a bee sting.
Medical Significance
Low danger level. The mechanical damage from large fangs can be painful, but the venom is non-lethal. Urticating hairs cause significant skin and eye irritation.
Safety Recommendations
Relocate using the 'cup and cardboard' method. Wear gloves if handling to avoid urticating hairs. Do not place near eyes/face.
Habitat & Behavior
Habitat & Range
Native to Central America, particularly Costa Rica and Panama. They inhabit tropical dry forests and rainforest floors in deep burrows.
Behavior & Temperament
Generally skittish or defensive rather than aggressive. If threatened, they may kick urticating hairs from their abdomen or assume a threat posture reaching up with front legs.
Diet & Prey
Opportunistic carnivore; feeds on large insects (crickets, roaches), and occasionally small vertebrates like lizards or mice in the wild.
Seasonal Activity
Active year-round in tropical climates, with increased activity (especially roaming males) during the onset of the rainy season.
Description
A classic 'heavy-bodied' tarantula, this species is a staple of Central American biodiversity, spending most of its time in cool, moist underground retreats.
Key Features
Large size, dense hair covering, terrestrial habits, and specific ocular tubercle position typical of family Theraphosidae.
Similar Species
Brachypelma vagans (Mexican Black Velvet), which has more distinct red abdominal hairs, or other Sericopelma species which require microscopic examination to distinguish.
Life Cycle
Females can live 15-20 years; males significantly shorter. Mating involves complex drumming; females produce silk-wrapped egg sacs containing hundreds of spiderlings.
Ecological Importance
Significant apex invertebrate predator; controls populations of large insects and provides a food source for larger mammals and birds.
Conservation Status
Not currently listed by IUCN, but many Central American tarantulas face threats from habitat destruction and the illegal pet trade.
Interesting Facts
These spiders have 'urticating hairs'—barbed bristles that they flick at predators' eyes and noses as a primary defense mechanism.
Photography Tips
Focus on the cephalothorax (head region) for clarity. Use a soft flash to bring out the subtle reds and browns in the hair without blowing out the highlights.
Identified: 2026-07-20T16:51:54.600448