The gnaphosid spider genus Sernokorba Kamura, 1992 is reviewed. While Sernokorba pallidipatellis (Bösenberg and Strand 1906) and Sernokorba fanjing Song, Zhu & Zhang, 2004, occur in the Far East and the Japanese archipelago, Sernokorba tescorum (Simon, 1914) is known from Europe. We here describe a fourth species, Sernokorba betyar sp. nov. (male and female) from the forest steppe vegetation in southern Hungary in Central Europe. Digital images, comparative drawings (except for S. fanjing) and a distribution map are provided for all the species, and an identification key is compiled. The cheliceral dentation as diagnostic character and its interpretation are discussed.

Central Europe, forest steppe, identification key, new species, spider

Kamura (1992) described the monotypic ground spider genus Sernokorba to accommodate Prosthesima pallidipatellis Bösenberg & Strand, 1906 from Japan, which was at that time placed in Zelotes Gistel, 1848, since it lacks the preening comb on metatarsi III–IV characteristic of the genus. The species occurs also in China (Song et al. 1999), Korea (Namkung 2002) and Russian Far East (Marusik 2009). According to Kwon et al. (2014), this ground-dwelling species occurs in a wide variety of habitats, in forests, vineyards and grasslands. Currently, three species of the genus are known. The second species, Sernokorba fanjing Song, Zhu & Zhang, 2004 was described from Mt. Fanjing, Guizhou, China.

The third species occurs in Europe. It was originally described as Poechilochroa tescorum Simon, 1914 on the basis of a female specimen. In their recent study, Cornic and Ledoux (2013) revised the species, described the male and proposed a new combination, Sernokorba tescorum (Simon, 1914). The species has been collected in nine locations in southern France, in grasslands and pine forests on calcareous soil. Later, Hernández-Corral et al. (2017) and Breitling (2018) provided new occurrence data from the Iberian Peninsula, from a Quercus rotundifolia, Lamarck forest and a dry grassland, respectively. Naumova et al. (2021) reported the species from Bulgaria, from the leaf litter of a mixed forest of Fagus sylvatica, Linnaeus and Pinus heldreichii, Christ. In this paper we report, describe and illustrate Sernokorba specimens from Hungary for the first time, belonging to a hitherto unknown species, which we hereby describe as new to science. We provide an identification key, and illustrate occurrences of the genus, except for S. fanjing.

The specimens of the new species were collected in the calcareous sand-dune area of the Kiskunság, central Hungary. The region belongs to the forest steppe zone, the transitional biome between the temperate deciduous forest and the steppe zones in Eurasia (Gallé et al. 2022a). The region has a semiarid continental climate, as the mean annual precipitation is between 500–550 mm and the annual temperature is between 10 °C and 12 °C (Gallé et al. 2022a). The calcareous soil is poor in organic matter (Tölgyesi et al. 2018). The forest steppe vegetation appears as a mosaic of (1) open dry grasslands: brome sward (Brometum tectorum), caliciphilous festuca steppe (Festucetum vaginateae) and Pannonian sand grassland (Potentillo-Festucetum pseudovinae), (2) wind-grooves between the sand dunes: more humid, with dune-slack purple moorgrass meadow (Molinio-Salicetum rosmarinifoliae) as main vegetation type, and (3) small forest patches of native arboreal plants such as Populus alba, Crataegus monogyna and Juniperus communis. Spiders were sampled with funnel traps (Császár et al. 2018), near Fülöpháza in an intact forest steppe fragment, approximately 3.3 km² (46°52'N, 19°24'E, Figs 1–4). A total of 10 sites were established, and in each site, three habitat types (grassland, forest and forest edge) were sampled with four traps in each habitat. Samplings were done between 18 May and 12 June 2014. We collected 21 out of the 28 specimens in the forest edges.

Figures 1–4. 

The habitat and distribution of Sernokorba species; 1, 2. Habitat of S. betyar in Fülöpháza (Hungary); 3. Occurrences in Europe, red dots: S. betyar, yellow dots: S. tescorum; 4. Occurrences in Asia, green dots: S. pallidipatellis.

Type material of the new species will be deposited in the Hungarian Museum of Natural History, Budapest (HMNH, curator: E. Deákné Lazányi-Bacsó). A male of S. tescorum has been kindly loaned to us by Antonio Melic (Sociedad Entomológica Aragonesa: PCAM). Specimens of S. pallidipatellis have been kindly donated to HNHM (Hungarian Natural History Museum, Budapest,) by Prof. Takahide Kamura (Otemon Gakuin University). We did not have access to specimens of S. fanjing.

Specimens were photographed using a Nikon D300S camera and a Tucsen TrueChrome Metrics camera attached to a Nikon S800 stereomicroscope and a Nikon Eclipse E200 compound microscope at the Department of Ecology, University of Veterinarian Medicine Budapest. Digital multifocal images were assembled using HeliconFocus image stacking software. Epigynes were removed and illustrations of them were made after a day-long maceration in commercial pancreatic enzyme solution. Palps were examined immersed in methyl-salicylate and mounted in a slightly modified Coddington mount (Coddington 1983). We modified the mount as the coverslip is not horizontal, but touching the slide itself, thus creating a triangle allowing more precise manipulation and more stable fixation of the object. Illustrations of the new species, S. tescorum and S. pallidipatellis were redrawn from digital images, while for S. fanjing they were produced from the figures of the original description (Song et al. 2004). We used Adobe Illustrator CS6 vector graphics software. We illustrated the distribution of the Sernokorba species with Google Earth satellite images, and Adobe Photoshop CS6 software.

Measurements are given in mm. Lengths of leg segments and total length were measured on the dorsal view. Leg formula developed by Ono (1988) is used; lengths of leg segments are given as: total length (femur, patella, tibia, metatarsus, tarsus).

In the genus description of Sernokorba, Kamura (1992) mentioned concerning S. pallidipatellis: “I recognized that this species is unique in having a serrated carina on the promargin of fang furrow of chelicera”, unequivocally illustrated (Kamura 1992: fig. 3), and used in this sense by subsequent authors (Song et al. 2004; Kim and Lee 2013) for S. fanjing and S. pallidipatellis. However, Cornic and Ledoux (2013) reports teeth, but only on the promargin: “Marge antérieure des chélicères garnie de trois dents, marge postérieure mutique”. We compared the dentation of specimens of S. pallidipatellis (Figs 48–50) to both literature images and to that of S. betyar sp. nov. (Figs 51, 52). The cheliceral dentation of S. pallidipatellis (Figs 48–50) looks almost identical to literature sources (Kamura 1992: fig. 3). However, we also agree with Cornic and Ledoux (2013) and interpret it as teeth rather than a keel or carina. Azevedo et al. (2018) well illustrated the non-serrated cheliceral promargin (Azevedo et al. 2018: fig 20. e, g), which is diagnostic to the subfamily Herpyllinae. However, the keel on the promargin may not just “be a subtle projection or may appear as teeth with fused bases” (Kamura 1992). Despite Kamura’s (1992) description and subsequent authors (Song et al. 2004; Kim and Lee 2013) implies the latter; we observed that the bases of the teeth are in fact separated as viewed from an oblique view (Figs 49, 50). We observed five teeth lumped together with a smaller one further placed, whereas there was one clear tooth on the retromargin. Such dentation has been observed (but not illustrated) in Latonigena Simon, 1893 by Ott et al. (2012), thus this character may require a second look with more genera involved. The dentation of S. betyar sp. nov. (i.e., two teeth on the promargin and one on the retromargin, Figs 51, 52) is different also from S. tescorum (i.e., three teeth on the promargin, none on the retromargin) which seems a good confirmation to separate the two species.

Figures 48–52. 

Male chelicerae; 48–50. Sernokorba pallidipatellis; 51, 52. Sernokorba betyar sp. nov.

Species of the genus occur in a wide variety of habitats including lowland forests and grasslands, however, specimens were collected mainly in mountainous regions (Kwon et al. 2014; Hernández-Corral et al. 2017; Naumova et al. 2021). According to our data, S. betyar sp. nov. is a typical member of the ground-dwelling spider fauna of lowland forest steppes. The relatively understudied forest steppes of Central Europe are among the most complex ecosystems in the region, and their nature conservation value is high. Forest steppes are important biodiversity hotspots (Gallé et al. 2022b) and listed in the Habitats Directive of the European Union. They harbour numerous endemic and rare plant and animal species, including several recently described spiders such as Parasyrisca arrabonica Szinetár & Eichardt, 2009 (Gnaphosidae) and Alopecosa psammophila Buchar, 2001 (Lycosidae). Although the abundance of S. betyar sp. nov. seems to be very low, this species presumably occurs in vast areas of forest steppes of Central and Eastern European forest steppes.

The study would have been impossible to carry out without the valuable help of colleagues who have sent comparative material of S. pallidipatellis (Takahide Kamura; Otemon Gakuin University), and S. tescorum (Antonio Melic; Sociedad Entomológica Aragonesa). This work was supported by the Hungarian National Research, Development and Innovation Office (Grant Id: NKFIH-FK-142926; NKFIH-KKP-133839). RG was supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences.