Ceratogyrus

Ceratogyrus is a genus of tarantulas found in southern Africa. They are commonly called horned baboons for the foveal horn found on the peltidium in some species.

Ceratogyrus
Ceratogyrus darlingi
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Class:	Arachnida
Order:	Araneae
Infraorder:	Mygalomorphae
Family:	Theraphosidae
Genus:	Ceratogyrus Pocock, 1897
Species
10, species text.
Synonyms
Coelogenium Purcell, 1902

Ceratogyrus dolichocephalus

Diagnosis

They are readily distinguished from other African theraphosid genera by the combined presence of a retrolateral cheliceral scopula, composed of plumose, stridulatory setae, and the strongly procurved fovea. The fovea is typically strongly procurved and in some species surrounds a distinct protuberance. This protuberance may take the form of a simple posterior extension of the caput, a low-set plug or a prominent, discrete conical projection. All Ceratogyrus species possess a pale yellow anteriorly placed, transverse, sub-abdominal band. This feature is not distinct in other Harpatirinae except Augacephalus junodi. The absence of dense, ventral femoral fringes on the palpi and legs I and II distinguish Ceratogyrus spp. from female A. junodi.

Horn function

The horn of C. marshalli stands straight up about 1 cm in an adult. There are several probable functions for this horn: according to a study by Rick C. West in 1986, it provides an increased surface for the attachment of the dorsal dilator muscle, which aids in drawing in liquefied food into the sucking stomach at a faster rate; this way, the spider can retreat to a safe place faster. It also increases the area for the midgut diverticula to expand during times of nutrient and water availability, analogous to a camel's hump, helping it to survive in its arid habitat during droughts.

Species

As of July 2022, the World Spider Catalog accepted the following species:

• Ceratogyrus attonitifer Engelbrecht, 2019 – Angola
• Ceratogyrus brachycephalus Hewitt, 1919 – Botswana, Zimbabwe, South Africa
• Ceratogyrus darlingi Pocock, 1897 (type species) – Southern Africa
• Ceratogyrus dolichocephalus Hewitt, 1919 – Zimbabwe
• Ceratogyrus hillyardi (Smith, 1990) – Malawi
• Ceratogyrus marshalli Pocock, 1897 – Zimbabwe, Mozambique
• Ceratogyrus meridionalis (Hirst, 1907) – Malawi, Mozambique
• Ceratogyrus paulseni Gallon, 2005 – South Africa
• Ceratogyrus pillansi (Purcell, 1902) – Zimbabwe, Mozambique
• Ceratogyrus sanderi Strand, 1906 – Namibia, Zimbabwe

In synonymy

• Ceratogyrus bechuanicus (Purcell, 1902) = Ceratogyrus darlingi
• Ceratogyrus cornuatus (De Wet & Dippenaar-Schoeman, 1991) = Ceratogyrus marshalli
• Ceratogyrus schultzei Purcell, 1908 = Ceratogyrus darlingi

Transferred to other genera

• Ceratogyrus ezendami Gallon, 2001 → Augacephalus ezendami
• Ceratogyrus nigrifemur (Schmidt, 1995) → Augacephalus junodi
• Ceratogyrus raveni (Smith, 1990) → Pterinochilus chordatus

References

• Pocock, R.I. (1897). On the spiders of the suborder Mygalomorphae from the Ethiopian Region, contained in the collection of the British Museum. Proceedings of the Zoological Society of London 1897:724-774.
• West, R.C. (1986). Ceratogyrus. Journal of the British Tarantula Society 1(4):79-80.
• Gallon, R.C. (2001). Revision of the Ceratogyrus spp. formerly included in Coelogenium (Araneae: Theraphosidae, Harpactirinae). Mygalomorph 2:1-20. PDF
• Messenger, P. (2004). Captive Breeding Ceratogyrus meridionalis. J. Brit. Tarantula Soc. 19(4):113-117. PDF
• Gallon, R.C. (2005c). A new species of theraphosid spider from Southern Africa (Araneae, Theraphosidae, Harpactirinae) with distributional notes on other harpactirines. Bull. Br. arachnol. Soc. 13(5):179-184. PDF (C. paulseni)

External links

• Reference list
• Photos of three Ceratogyrus species in gallery of tarantulas.