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Spider species distribution in the Cape Floristic Kingdom (CFK) was compiled as part of the South African National Survey of Arachnida (SANSA), whose main aim was to create a relational database for the country's arachnid fauna. Data from the CFK was extracted from taxonomic and faunistic published papers, as well as unpublished faunistic survey data in national collections. A total of 11 500 records from 130 localities were recorded in the CFK until the end of 2023, representing 62 families, 334 genera and 960 species, with two further families (Synotaxidae and Theridiosomatidae) only known from undescribed species. This represents 42.4% of the total spider fauna of South Africa. For each species, the global and CFK distribution, as well as the level of endemicity and a conservation assessment using the IUCN Red List criteria, are provided. A total of 269 spp. (28.0%) are endemic to the CFK, 49 spp. (5.1%) are of special concern, and 229 spp. (23.9%) are Data Deficient. However, most of the species (682 spp., 71.0%) have a wide distribution with no known threats and are categorised as Least Concern. Salticidae is the most species-rich family (128 spp.), with 30 spp. endemic to the CFK, followed by the Gnaphosidae (107 spp.), Thomisidae (86 spp.) and Lycosidae (49 spp.), while six families are represented by a single species. The last decade has seen an exponential growth in the knowledge of spiders in South Africa, and there are certainly many more species that must still be discovered and described. [ABSTRACT FROM AUTHOR]

Many human activities have an impact on the fauna and flora of the South African Grassland Biome, including agriculture, fire and urbanisation. Disturbances in grassland habitats often result in Hyparrhenia hirta, a native pioneer grass species, establishing dense stands. Here the assemblage composition, species richness and abundance of spiders associated with H. hirta tussocks was investigated at three grassland sites (annually burnt, suburban local road traffic and undisturbed control) in the central Free State Province of South Africa during winter 2015 and 2016. Further, inter-annual differences during a period of intense drought were evaluated. An increase in spider species richness, abundance and different assemblage composition with increased tussock height and basal circumference was expected, and we predicted these effects would differ between land use types. Overall, Tibellus spp. immatures (Philodromidae) and Poachelas striatus Haddad & Lyle, 2008 (Trachelidae) were the most abundant spider species, while Philodromidae and Gnaphosidae were the most abundant spider families at all three sites during both years. The most species-rich families were Gnaphosidae, Salticidae and Thomisidae. Over the two-year sampling period there was a significant decline in overall spider abundance (58.09 %) and species richness (28.17 %), which could be explained by the cumulative effects of a severe drought experienced in central South Africa during 2015 and 2016. Species richness and assemblage composition were influenced by tussock basal circumference and disturbance effects, but not by tussock height. Several species were associated with the control site, while certain diversity metrics of the burnt and road verge sites were more stable, pointing to the importance of primary productivity in the former and water in the latter, for spider diversity. Trade-offs related to disturbance need to be carefully considered when developing management strategies for biodiversity. [ABSTRACT FROM AUTHOR]

Spiders are a prominent group of predatory arthropods in most terrestrial ecosystems, and are especially diverse in the Savanna Biome of South Africa. Despite this, there is a considerable paucity of information on spider assemblages in particular microhabitats, including tree bark. The spiders associated with the bark of Vachellia xanthophloea (fever trees) were studied at five wetland sites in the Ndumo Game Reserve, South Africa. The influence of various seasonal, habitat and phenological effects on spider assemblages was investigated. In total, 8341 spiders were collected, of which only 2726 were adults (32.7%), representing 25 families and 108 species. While total spider abundance and adult species richness did not differ significantly between sites, significant differences were found in adult abundance and in overall assemblages between sites. There were also no significant seasonal effects on spider assemblages and guild composition. Only eight of the species collected can be considered exclusive bark-dwelling spiders, while similar proportions are facultative bark-dwellers (43.5%) or accidental bark-dwellers (49.1%). This study demonstrates that targeted sampling of specialised microhabitats can yield a significant proportion of the spider diversity in a particular locality, and can contribute to understanding patterns of biodiversity in conserved areas. [ABSTRACT FROM AUTHOR]

The karyotypes of pseudoscorpions of the family Atemnidae (Arachnida: Pseudoscorpiones) were studied for the first time. Karyotype data for 7 species have been obtained. The diploid chromosome numbers of most species considerably exceed the numbers reported in pseudoscorpions so far, with males ranging between 65 and 143. In spite of this, the sex chromosome system of atemnids is characterized by the same features that are found in the majority of other pseu doscorpions with an X0 system; the X chromosome is meta centric and is the largest chromosome or one of the largest chromosomes of the karyotype. Male meiotic cells of Atemnus politus contain 1 or 2 autosome multivalents; most specimens had 2 multivalents. The multivalents were composed of 4,6,8 or 10 chromosomes. Multivalent number and structure was consistent within each of the studied individuals. The same number of chromosomes in all of the males examined suggests that multivalents are generated by reciprocal translocations. The high diversity of multivalents suggests considerable range of translocation heterozygosity in the Studied population. [ABSTRACT FROM AUTHOR]

A new species of the endemic South African sac spider genus Spinotrachelas Haddad, 2006 is described. Spinotrachelas montanus sp. n. is described based on material collected from four localities in the uKhahlamba-Drakensberg mountains, representing the first records of the genus from the east of the country and from the Grassland Biome. [ABSTRACT FROM AUTHOR]

The spider diversity found in the Savanna Biome are discussed. A total of 1207 species from 62 families are known from this Biome alone, of which 36% are endemic to the savanna. [ABSTRACT FROM AUTHOR]