Phormictopus

Dominik Alexander
Nov 11, 2025
3 min read

Updated: Dec 7, 2025

Phormictopus is a New World tarantula genus in the family Theraphosidae, native mainly to the Greater Antilles (Cuba, Hispaniola and nearby Caribbean islands). A few species historically reported from South America (Brazil and Argentina) are now suspected to be misassigned and may eventually be moved to other genera.

The genus was formally established in 1901 by British arachnologist Reginald Innes Pocock. He took a large Caribbean tarantula originally described as Mygale cancerides by Pierre André Latreille in 1806 and designated it as the type species of his new genus, renaming it Phormictopus cancerides.

Through much of the 20th century, Phormictopus became a kind of “catch-all” for big, robust brown or purple tarantulas from the Caribbean and surrounding regions. By the early 2000s, around 14 species names were associated with the genus, but many were poorly defined or based on limited material.

In 2008, Jan-Peter Rudloff published a modern revision of Phormictopus. He re-evaluated the existing material, confirmed that only seven species clearly belonged in the genus, described five new species, and pointed out that three South American species were probably misplaced. His work reinforced the idea that “true” Phormictopus is essentially a Caribbean genus, centered on Cuba and Hispaniola.

Today, depending on whether you follow World Spider Catalog or other databases, there are roughly 14 accepted species in Phormictopus, plus several synonyms and names considered doubtful (nomena dubia). As taxonomy continues to be refined, the exact species list may change, but Phormictopus cancerides remains the classic and best-known representative of this impressive Caribbean genus.

Genus and species: Phormictopus sp. green femur

Common name: Green Femur

Given name: Matcha

Sex: Suspected female

Life stage: Adult

This species is considered a color variant, and at this time, not well classified.

Habitat:

Specimen Notes:

Approximately 6.25 inches and room to grow
Skittish if disturbed but typically on display
Decent eater may not takedown immediately
At times turns psychotically twitchy.

Genus and species: Phormictopus sp. Dominican Purple

Common name: Dominican Purple

Given name: Fig

Sex: Male

Life stage: Adult (hooked out)

As with many Phormictopus sp., taxonomy is inconsistent. sp. Dominican Purple is a color variant and some refer to this species as P. cautus (but the accuracy has not been verified). This is a highly temperamental species, who commonly displays threat poses.

Habitat: The natural habitat of this species is not well described, but likely resides in semitropical regions with rocky and hilly habitat.

Specimen Notes:

Approximately 6.5 to 7 inches
Highly defensive and nasty. However, typically out on display.
Decent but may not takedown immediately. Has not been an aggressive eater as of late.
Had a beautiful coloration; deep and rich purple after final molt. The bright purple has faded as of late.

Genus and species: Phormictopus atrichomatus

Common name: Red Island birdeater

Given name: Cayenne

Sex: Uncertain

Life stage: Juvenile

This species typically grows relatively fast and has a Phormictopus attitude. Many keepers comment about their aggressive attitude. P. atrichomatus is native to the West Indies, including Cuba and Hispaniola. Origins believed to be Hispaniola (which includes Haiti and the Dominican Republic).

Habitat: Terrestrial; dry tropical forests.

Specimen Notes:

Approximately 4 inches
Relatively calm thus far but can be skittish at times. Starting to get a little more high strung.
Decent eater but may not takedown immediately
Digs burrows and thoroughly messes up the enclosure