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.

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

The National Geographic Okavango Wilderness Project (OWP) was initiated in 2015 to investigate biodiversity in the entire Okavango catchment of Angola, Namibia and Botswana, and to introduce sustainable conservation in the area. Previous assessments of the Okavango system have focussed on the delta in Botswana only, due in part to civil war in Angola, where the majority of the catchment is located. Access to central Angola is also logistically difficult, resulting in a sampling gap where high potential for biodiversity exploration exists.

Published records of Theraphosidae from Angola are rare, compared to other southern African countries (Smith 1990, Gallon 2002, 2008, Gallon and Engelbrecht 2011, van Noort and Ranwashe 2017, Denver Museum of Nature & Science 2018, Grant and Maier 2018, iNaturalist.org 2018, Lyle and Ranwashe 2018, Senckenberg 2018, Tarantupedia 2018), with only nine species in five genera currently known from the country (Figure 1, Table 1). Many Afrotropical ecoregions converge in Angola, resulting in high biodiversity and endemism of other taxa (Myers et al. 2000). When the low diversity of theraphosids and high diversity of other taxa are considered together, it suggests a lack of knowledge of Angolan Theraphosidae, making any new collections potentially important.

Figure 1. 

Map of the Okavango Wilderness Project study region in south-eastern Angola, known records of baboon spiders (Araneae: Theraphosidae) for Angola and adjacent parts of neighbouring countries, and extent of miombo woodland. Inset shows Cabinda Province. Prepared in QGIS V3.2 using publicly available spatial layers from the World Wildlife Foundation (Olson et al. 2001), www.naturalearthdata.com and www.mapcruzin.com. Background is shaded relief.

The genus Ceratogyrus Pocock, 1897 currently includes nine species, with most confined to southern Africa. These are C. brachycephalus Hewitt, 1919, C. darlingi Pocock, 1897, C. dolichocephalus Hewitt, 1919, C. hillyardi (Smith, 1990), C. marshalli Pocock, 1897, C. meridionalis (Hirst, 1907), C. paulseni Gallon, 2005, C. pillansi (Purcell, 1902) and C. sanderi Strand, 1906 (World Spider Catalog 2018). Those species which occur outside of southern Africa, as traditionally defined as the area south of the northern borders of Namibia, Zimbabwe, and the Zambezi river in Mozambique, are C. sanderi which extends into Zambia and Malawi, and C. meridionalis which occurs in Malawi and Mozambique north of the Zambezi River. We describe a remarkable new species collected from the Okavango catchment in Angola and also report on new records for other theraphosid genera collected from the OWP survey region and their implications for the current understanding of the diversity, distribution and ecology of this family in the country.

Specimens were collected during the 2015 and 2016 OWP field trips in central Angola. Sampling areas fell within miombo (Brachystegia) woodland with associated dambos (seasonal wetlands, Figure 2A). Spider burrows were located during the day and excavated at night when conditions were more conducive to collecting. Wandering male theraphosid spiders were collected in pitfall traps and by active searching under logs and other surface cover. Sampling took place throughout the landscape, but female theraphosids were only collected from the dambos and marginal miombo.

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.

Specimens were photographed in the wild and then killed humanely and preserved in 80% ethanol. Digital images of the cephalothorax were taken using a Canon 5D Mark II camera with a Tamron 90mm macro lens. Images of ocular tubercle and spermathecae were taken using a high resolution AxioCam MRc5 camera mounted on a Zeiss Axio Zoom V16 microscope. Measurements of the carapace, palps, and legs were taken using Vernier callipers accurate to 0.5mm. Ocular measurements were taken on the same Zeiss Axio Zoom V16 microscope. Counts of cuspules on the labium and maxilla were taken from images using the Count Tool in Adobe Photoshop CC. Clavate trichobothria on the tarsi were counted directly under the microscope. Counts for cuspules and clavate trichobothria were taken from four specimens and ranges are presented. Terminology for the description follows that of Gallon and Engelbrecht (2011). Abbreviations are AER: anterior eye row; ALE: anterior lateral eyes; AME: anterior median eyes; DPD: distal prodorsal; DPV: distal proventral; DRD: distal retrodorsal; DRV: distal retroventral; PER: posterior eye row; PLE: posterior lateral eyes; PME: posterior median eyes. Specimens are deposited in the Albany Museum, Grahamstown (AMGS), National Collection of Arachnida, Pretoria (NCA), the KwaZulu-Natal Museum, Pietermaritzburg (NMSA), and the Museum für Naturkunde, Berlin (ZMB). Maps of the survey area were prepared in QGIS 3.2 using publicly available spatial layers from the World Wildlife Foundation (Olson et al. 2001), www.naturalearthdata.com and www.mapcruzin.com.

Known locality records for theraphosids were extracted from the Tarantupedia (www.tarantupedia.com) and the Global Biodiversity Information Facility (van Noort and Ranwashe 2017, Denver Museum of Nature & Science 2018, Grant and Maier 2018, Lyle and Ranwashe 2018, Senckenberg 2018), the largest available databases of Theraphosidae locality records, and include published records from the primary taxonomic literature. These served as the basis for assessment of the new records collected during the survey. The specific locality details of the new records are redacted from this publication due to concerns that they may facilitate illegal collecting for the pet trade (see Lindenmayer and Scheele 2017). Researchers and conservation officials interested in those records may obtain them directly from the institutions where the specimens are deposited.

The new species of Ceratogyrus described here is remarkable. No other spider in the world possesses a similar foveal protuberance. The function of the foveal protuberance, or ‘horn’, in Ceratogyrus is uncertain. Members of other theraphosid genera from the Neotropics, namely Cyrtopholis Simon, 1892, Sphaerobothria Karsch, 1879 and Umbyquyra Gargiulo, Brescovit & Lucas, 2018, also possess similar foveal structures, as do some species of the ctenizid genus Stasimopus in South Africa, and several aganippine idiopid genera from Australia (M. Rix pers. comm.). The protuberance of C. attonitifer is unique in its length, as well as being soft, whereas this structure is fully sclerotized in all other genera where it is known to occur.

Prior to, and even including, this work, very little was known about Angolan Theraphosidae, as is the case for Angolan biodiversity in general. Despite being a minor contribution, the new records presented here and the synopsis of historical records represents, to the best of our knowledge, the most complete assessment of the Angolan theraphosid fauna to date. Previous records are limited to the western quarter of the country, highlighting the paucity of biodiversity data for central and eastern Angola (Figure 1). Biodiversity exploration in Angola still offers many potential new scientific discoveries, particularly in the eastern provinces.

The occurrence of the genus Ceratogyrus in central Angola represents a substantial range extension for the genus. Ceratogyrus is known primarily from southern Africa, south of the Cunene and Zambezi Rivers, and is most diverse in Zimbabwe with six of the nine previously described species occurring there. One species, C. sanderi Strand, 1906, has also been recorded in the southern parts of Angola (Table 1, van Noort and Ranwashe 2017), and several records have been obtained from Zambia and Mozambique through an atlas project driven primarily by citizen scientists (Campbell and Engelbrecht 2018). The collection of Ceratogyrus attonitifer sp. n. and another potentially undescribed Ceratogyrus in Angola represents a range extension of approximately 400 km for the genus. Its occurrence in miombo woodland suggests that the genus may be more widely distributed in central Africa. The miombo woodland ecoregion extends from the southern parts of the Democratic Republic of Congo (DRC) through central and eastern Angola, most of Zambia and Zimbabwe, and into Tanzania and Mozambique. Extensive collecting effort will be required to establish the true distribution of this genus in the country.

The genus Pterinochilus is known from four species in Angola, P. cryptus Gallon, 2008, P. murinus Pocock, 1897, P. simoni Berland, 1917 and P. vorax Pocock, 1897. Pterinochilus murinus is a widespread species in east and central Africa, occurring from southern Kenya through Tanzania, Mozambique, the southern DRC, Zambia and Zimbabwe. There is a single published locality record from southwestern Angola, although the lack of records from elsewhere in the country is likely a result of lack of collecting rather than absence of the species. Pterinochilus cryptus is described from the arid south western part of the country (Gallon 2008), and appears to be widely distributed in that arid ecoregion (M. Sakko, pers. comm.). Pterinochilus simoni is known from the enclave of Cabinda in the north of Angola, and occurs throughout the central and northern parts of the DRC. Pterinochilus vorax is known from a two records in the north west of the country, and also occurs in the southern DRC and northern Zambia Gallon 2002). The discovery of P. lugardi during the Okavango Wilderness Project surveys increases the total number of species known for Angola to five. Together with the potentially undescribed species recorded during the survey, these records extend the distribution range of the genus in Angola by almost 600km. The single record of P. murinus is from within the miombo woodland ecoregion, and the new records from this survey again indicate the wider distribution of the genus in miombo.

The genus Phoneyusa is represented by two species in Angola, P. gracilipes (Simon, 1889) and P. westi Smith, 1990. Both are known from single records from the north-western parts of the country, P. gracilipes from Landana, Cabinda and P. westi from Dondo (Smith 1990). The locality “Dondo” is somewhat uncertain, as multiple settlements in Angola have this name (in the provinces Huambo, Huila, Cuanza Norte and Uige), or similar names (e.g. Dundo, Lunda Norte). As the collection date predates the founding of Dundo, we have considered the spelling to be correct. We have assumed the largest settlement, in Cuanza Norte, to be correct. Access from Luanda was possible in the early 1900s, after the construction of the Luanda Railway in 1889. All Dondo localities are in western Angola and so, despite some uncertainty, do not diminish the importance of the new locality. The collection of the unidentified female specimen of Phoneyusa in central Angola (NCA 2018/331) during this survey represents a range extension for the genus of over 600 km and the first record for the country from miombo woodland. Currently the genus is poorly known taxonomically and requires revision (Smith 1990). Collection of adult males should be a priority for revisionary work. Only on completion of a revision would it be possible to determine if this new locality record represents a broader ecological niche width of a known species or a new species which may have evolved independently in miombo woodland.

Despite only presenting data for twelve specimens, this study has shown significant range expansions for three genera. The general paucity of biodiversity data for Angola is clearly illustrated by this example with theraphosid spiders, highlighting the importance of collecting specimens in biodiversity frontiers.

We would like to thank the follow people and organisations. The National Geographic Okavango Wilderness Project funded the expeditions where the specimens were collected. Kostadine Luchansky provided images taken in the field, and Werner Conradie and Götz Neef assisted with fieldwork and transport of the specimens. The research was supported by the KwaZulu-Natal Museum and the University of Pretoria. Rick West and Fernando Perez-Miles provided valuable comments on the manuscript. Our interpretations do not necessarily reflect the opinions of Okavango Wilderness Project or its sponsors in any way.