''Hemirrhagus billsteelei'' is a

tarantula Tarantulas comprise a group of large and often hairy spiders of the family Theraphosidae. , 1,040 species have been identified, with 156 genera. The term "tarantula" is usually used to describe members of the family Theraphosidae, although ...

in the ''

Hemirrhagus ''Hemirrhagus'' is a genus of Mexican tarantulas that was first described by Eugène Louis Simon in 1903. It is considered a senior synonym of ''Spelopelma''. Species of the genus ''Hemirrhagus'' are 5 to 12 cm long, usually black in colour, the ...

'' genus of Mexican cave tarantulas. This tarantula is found in the

Mexican Mexican may refer to: Mexico and its culture *Being related to, from, or connected to the country of Mexico, in North America ** People *** Mexicans, inhabitants of the country Mexico and their descendants *** Mexica, ancient indigenous people ...

state of

Oaxaca Oaxaca ( , also , , from nci, Huāxyacac ), officially the Free and Sovereign State of Oaxaca ( es, Estado Libre y Soberano de Oaxaca), is one of the 32 states that compose the political divisions of Mexico, Federative Entities of Mexico. It is ...

. This tarantula was first described by Mendoza and Francke in 2018, and is named in honour of Bill Steele, because of his contributions of knowledge in Mexican caves.

Description

This tarantula is purely black in colour, with some grey tones. It has a slender body, as it is advantageous for traversing through crevices. It can be distinguished from all other Hemirrhagus species, with the exception of ''Hemirrhagus perezmiles'', in that it lacks tibial apophyses. It can be distinguished from the ''Hemirrhagus perezmiles'' as the shape of male

palpal bulb The two palpal bulbs – also known as palpal organs and genital bulbs – are the copulatory organs of a male spider. They are borne on the last segment of the pedipalps (the front "limbs" of a spider), giving the spider an appearance often descr ...

is different. This tarantula can be found below the Cueva La Grieta entrance. Further inside the same cave '' Hemirrhagus grieta'' is found, but at a much deeper level, from about in, but the grieta tarantula is thinner and more slender, and a different colour.

References

Natural history of Oaxaca Endemic spiders of Mexico Cave spiders Theraphosidae Fauna of the Sierra Madre de Oaxaca Spiders described in 2018 {{Mygalomorphae-stub