Wednesday, February 13, 2019

[Arachnida • 2019] Ceratogyrus attonitifer • A Remarkable New Species of Ceratogyrus: New Collection Records for Theraphosidae (Araneae, Mygalomorphae) in Angola


Ceratogyrus attonitifer Engelbrecht

in Midgley & Engelbrecht, 2019. 

Abstract
During 2015 and 2016 several baboon spider specimens (Araneae: Theraphosidae) were collected in central Angola during surveys undertaken for the Okavango Wilderness Project. These collections represent range and habitat extensions for Pterinochilus Pocock, 1897, Ceratogyrus Pocock, 1897 and Phoneyusa Karsch, 1884. The new species Ceratogyrus attonitifer sp. n. is described from female specimens and the distribution of genera mapped. Central and eastern Angola is severely under sampled for theraphosid spiders, with every species collected during the survey either being potentially new to science or representing a significant range extension for the genus.

Keywords: Arachnida, Pterinochilus, Ceratogyrus, Phoneyusa, Theraphosidae, biodiversity, survey, taxonomy


Figure 2. Habitat, burrow and live habitus of Ceratogyrus attonitifer sp. n. in south-eastern Angola.
A Aerial view of habitat at the type locality showing a dambo (wetland) amongst miombo (Brachystegia) woodland. The expedition campsite is to the right of the dambo. Specimens were collected primarily along the margins of the wetland area B live habitus, dorsal, showing full size of the foveal protuberance in life C specimen in defensive posture typical for baboon spiders; background is white sand at the type locality D burrow entrance amongst grass tussocks; entrance approximately 2cm wide.




Taxonomy
Family THERAPHOSIDAE Thorell, 1869
Subfamily Harpactirinae Pocock, 1897

Genus Ceratogyrus Pocock, 1897
Ceratogyrus attonitifer Engelbrecht, 2019, sp. n.

Diagnosis: Ceratogyrus attonitifer sp. n. can be diagnosed from its congeners, and all other species of Theraphosidae, by the presence of a large, elongate protuberance which extends out of the fovea and over the spider’s abdomen (Figure 2).

Etymology: The specific epithet is derived from the Latin root attonit–, meaning astonishment or fascination, and the suffix –fer, bearer of or carrier, and refers to the astonishment felt by the authors at the discovery of this remarkable species.

Generic placement: The presence of distinct scopulae made up of plumose setae on the retrolateral surfaces of the chelicerae support the inclusion of this species in the Harpactirinae. The new species is placed in the genus Ceratogyrus on the basis of the presence of a foveal protuberance. While not all Ceratogyrus species possess a foveal horn or protuberance, all known species of the theraphosid subfamily Harpactirinae which do possess such a structure are placed within this genus. A diagnosis for the genus Ceratogyrus is provided in Gallon (2001).

Ecology: Ceratogyrus attonitifer sp. n. occurs in miombo woodland in south-eastern Angola. All specimens were collected from open burrows in sandy soil in dambos, between the high-water flood line and the miombo woodland edge (Figure 2A). Burrows (Figure 2D) were approximately 40 cm deep, and near vertical with a horizontal chamber at the bottom. Burrow entrances have a low collar made of silk and incorporate surrounding grass and twigs, but the collar is not as large and distinctive as in some other species of Ceratogyrus. The entrances are often hidden among grass tufts, but may also be found in open sand. Any object inserted into the burrow was attacked enthusiastically.

Indigenous knowledge: This species is known as “Chandachuly” in the Luchazi language. It was reported that they prey mainly on insects. The venom is not considered to be dangerous, though bites may result in infections which can be fatal due to poor medical access. It is claimed that the females enlarge existing burrows rather than digging their own burrows, though this needs to be verified as both behaviours are known in harpactirines.


 John M. Midgley and Ian Engelbrecht. 2019. New Collection Records for Theraphosidae (Araneae, Mygalomorphae) in Angola, with the Description of A Remarkable New Species of Ceratogyrus.  African Invertebrates. 60(1): 1-13. DOI: 10.3897/afrinvertebr.60.32141

New tarantula has a unique 'horn' on its back | Pensoft blog blog.pensoft.net/2019/02/12/new-tarantula-species-from-angola-distinct-with-a-one-of-a-kind-horn-on-its-back/ via @Pensoft