Araneae
|
publication ID |
https://doi.org/ 10.38201/btha.abc.v53.i1.13 |
|
persistent identifier |
https://treatment.plazi.org/id/304D87DA-5228-FFE4-FF00-AB18CC87FDB7 |
|
treatment provided by |
Felipe |
|
scientific name |
Araneae |
| status |
|
Araneae (spiders)
South Africa has the richest known spider fauna on the continent, with 2 268 described species currently recorded and many more awaiting description (Foord et al. 2020). Much of the current knowledge benefits from a rich collecting history, a well-developed museum infrastructure, and active local and international taxonomists that made sizable contributions to describing the fauna (Dippenaar-Schoeman et al. 2015).
Overall, the levels of spider endemism in South African forests are surprisingly low in terms of number of species (<10%), but when the area of each biome is considered, then forests have the highest level of endemism proportionally (Foord et al. 2020). The relatively low number of endemic species is unusual, considering the high levels of endemism reported for other invertebrates, such as snails ( Perera et al. 2021), millipedes ( Janion-Scheepers et al. 2016), harvestmen (e.g., De Bivort & Giribet 2010) and velvet worms (e.g., Daniels et al. 2009). This could possibly be attributed to: 1) the greater dispersal ability of spiders compared to the other invertebrate groups, and 2) undersampling of forests and other biomes in the Eastern Cape, which In total, 324 species of spiders were recorded from the Amathole Mountains, with Salticidae (49 spp.), Theridiidae and Thomisidae (28 spp. each) and Araneidae (26 spp.) the most species-rich families. In considering the various datasets used to assess the fauna of the Amathole Mountains, there is a clear sampling bias towards Hogsback (1 357 records), followed by Mpofu Fort Fordyce Nature Reserve (188 records), Qonce (formerly King William’s Town) (105 records) and Katberg (63 records), with the remaining sites all represented by fewer than 30 records ( Table 2). Hogsback has by far the highest recorded species richness (254 species), but even here the bulk of the records originate from forest habitats and plantations, and the grassland and fynbos biomes in the area remain comparatively poorly sampled. Increased sampling effort in these biomes, as well as the undersampled thicket and savanna biomes to the south, will likely result in the discovery of many new records for the area.
The Amathole Mountains fall within one of the areas with a moderate number of endemic South African spider species, none of which are considered rare or endangered (Foord et al. 2020). However, the apparent absence of certain ‘typical’ forest taxa from these mountains is perplexing. For example, all South African species of the family Archaeidae are endemic to the country, with three endemic to the Eastern Cape; most Afrarchaea Forster & Platnick, 1984 are forest-dwellers (Dippenaar-Schoeman et al. 2021). However, none have been sampled from Afromontane forests or grasslands in the interior of the Eastern Cape, despite several species occurring in these biomes in the KwaZulu-Natal Drakensberg and eastern Free State (Dippenaar-Schoeman et al. 2021). Similarly, the tiny litter-dwelling corinnid genus Hortipes Bosselaers & Jocqué, 2000 is represented by 14 species in the country, most of which occur in forest and savanna habitats, some in the Eastern Cape, but none have been record- ed to date from the Amathole Mountains (Bosselaers & Jocqué 2000). The web-building Eresidae are widespread throughout the country but have not yet been recorded from the region (Dippenaar-Schoeman et al. 2022).
Wandering spiders
More than two-thirds of the spiders from the Amathole Mountains (219 species in 35 families) are wandering species that actively search for prey or hunt from burrows. The ground-dwelling species most commonly collected in Afromontane forest litter include Copa kei Haddad, 2013 ( Corinnidae ; Figure 3A View Figure 3 ), Drassodella amatola Mbo & Haddad, 2019 ( Gallieniellidae ; Figure 3D View Figure 3 ), Microstigmata amatola Griswold, 1985 ( Microstigmatidae ; Figure 3F View Figure 3 ), tiny oonopid spiders of the genera Australoonops Hewitt, 1915 and Opopaea Simon, 1890 , and the jumping spiders Rumburak hilaris Wesołowska et al., 2014 ( Figure 3J View Figure 3 ), Thyenula alotama Wesołowska et al., 2014 ( Figure 3L View Figure 3 ) and Euophrys bifida Wesołowska et al., 2014 ( Salticidae ). Pachygnatha Sundevall, 1823 ( Figure 4E View Figure 4 ) is among the few genera of tetragnathids that do not build webs ( Levi 1980), and is represented by a new species that is common in the litter of all forest types. Many of the aforementioned species are also frequently sampled in pine plantations and mixed forest.
In the grassland and fynbos biomes, a very different ground- and grass-dwelling fauna is encountered, which includes Chumma foliata Jocqué & Alderweireldt, 2018 ( Amaurobiidae ), various lycosids including Proevippa bruneipes ( Purcell, 1903) ( Figure 3E View Figure 3 ) and Trabea Simon, 1876 spp. , several species of Scytodes Latreille, 1804 ( Scytodidae ), Heliophanus C.L.Koch, 1833 and Thyenula Simon, 1902 ( Salticidae ).
Some species are commonly associated with rocks and logs in forest habitats and plantations, including Lepthercus mandelai Ríos-Tamayo & Lyle, 2020 ( Entypesidae ; Figure 3B View Figure 3 ), which build a silk-lined burrow often covered with dead leaves ( Figure 3C View Figure 3 ), the flat wall spiders Anyphops amatolae ( Lawrence, 1940) ( Selenopidae ; Figure 4A View Figure 4 ) and A. gilli ( Lawrence, 1940) ( Figure 4B, C View Figure 4 ), and the scorpion spider Platyoides walteri (Karsch, 1886) ( Trochanteriidae ; Figure 4I View Figure 4 ).
A very rich fauna of arboreal spiders has been collect- ed by beating vegetation and canopy fogging, including various jumping spiders such as Asemonea amatola Wesołowska & Haddad, 2013 ( Figure 3G View Figure 3 ), Dendryphantes purcelli Peckham & Peckham, 1903 and D. silvestris Wesołowska & Haddad, 2013 , species of Myrmarachne MacLeay, 1839 ( Figure 3H, I View Figure 3 ), Rumburak mirabilis Wesołowska et al., 2014 ( Figure 3K View Figure 3 ), and two species of Wandawe Azarkina & Haddad, 2020 . Sac spiders of the families Clubionidae (10 spp.), Cheiracanthiidae (5 spp.) and Trachelidae (16 spp.) are especially species-rich compared to other parts of South Africa.Species such as Afroceto martini (Simon, 1897) ( Trachelidae ; Figure 4H View Figure 4 ) are some of the most abundant wandering spiders on shrubs and in trees. Two species of rain spiders, Palystes perornatus Pocock, 1900 , and P. superciliosus L. Koch, 1875 ( Figure 4D View Figure 4 ), can be easily recognised by their large size and by their nests, comprising a ball of leaves, woven together with silk, to accommodate their egg sacs. Certain taxa prefer particular kinds of trees, such as Oxytate ribes (Jézéquel, 1964) ( Thomisidae ; Figure 4F View Figure 4 ), which was only collected from broad-leaved trees and shrubs, whereas others have very flexible habitat requirements, such as crab spiders of the genus Thomisus Walckenaer, 1805 ( Thomisidae ; Figure 4G View Figure 4 ), which occur in grasses, herbs, shrubs and trees.
Web-builders
Approximately one-third of the spiders (105 species in 17 families) are web-builders. Species of Agelena Walckenaer, 1805 ( Agelenidae ; Figure 5A View Figure 5 ) and Hippasa Simon, 1885 ( Lycosidae ) build funnel-webs close to the ground in open grassy areas that are obvious when covered by dew-drops in the mornings. Other species common in grassy areas include various hammock-web spiders ( Linyphiidae ; Figure 5H View Figure 5 ), Neoscona subfusca (C. L. Koch, 1837) ( Araneidae ; Figure 5D View Figure 5 ), and tetragnathid orb-weavers of the genera Leucauge White, 1841 ( Figure 5K, L View Figure 5 ) and Tetragnatha Latreille, 1804 .
Araneid orb-weavers are a diverse group (26 species), with several large and charismatic species that can be seen in the forests, constructing orb-webs often 50 cm or more in diameter. These include the bark spider Caerostris sexcuspidata Fabricius, 1793 ( Figure 5B View Figure 5 ), species of Neoscona Simon, 1885 ( Figure 5D View Figure 5 ), and the golden orb-web spider Trichonephila fenestrata (Thorell, 1859) ( Figure 5E View Figure 5 ). Garbage-line spiders, Cyclosa insulana (Costa, 1834) ( Araneidae ; Figure 5C View Figure 5 ), build fine orb-webs with a vertical line of prey remains down the centre among which the spider rests. However, the most common orb-weavers seen in the forests are undoubtedly the species of Leucauge ( Figure 5K, L View Figure 5 ), which construct obliquely orientated orb-webs in low foliage and the herbaceous layer, and are brightly coloured in shades of green, silver, orange and red. Few web-building species are encountered on bark, predominantly including mesh web-building species of Themacrys Simon, 1906 ( Phyxelididae ; Figure 5I View Figure 5 ) and tiny Cyatholipidae , which construct small orb-webs in the buttresses and crevices of trees.
The assemblage of forest litter web-builders is dominated by Amaurobiidae , a group of small spiders <4 mm in length that build mesh-webs between dead leaves. Several web-builders construct webs under rocks and logs, including Vidole capensis (Pocock, 1900) and species of Xeviosa Lehtinen, 1967 ( Phyxelididae ), Steatoda Sundevall, 1833 , and Theridion Walckenaer,1805 ( Theridiidae ).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.