Notas / Notes

First record of Neoscona byzanthina (Pavesi, 1876) (Araneae, Araneidae) from the Iberian Peninsula

Carlos Mora-Rubio¹, Eduardo Morano² & José Luis Pérez-Bote³

¹Área de Zoología, Facultad de Ciencias, Universidad de Extremadura, Badajoz, 06006, España, cmorarub@alumnos.unex.es, ORCID iD: https://orcid.org/0000-0002-1847-3215

²DITEG Grupo de Investigación, Universidad de Castilla-La Mancha, Toledo, España, emorano@gmail.com, ORCID iD: https://orcid.org/0000-0003-1239-8370

³Área de Zoología, Facultad de Ciencias, Universidad de Extremadura, Badajoz, 06006, España, jlperez@unex.es, ORCID iD: https://orcid.org/0000-0002-4042-5391

The genus Neoscona Simon, 1864 is included in the family Araneidae Clerck, 1757. Currently, the genus includes 116 species with worldwide distribution (World Spider Catalog, 2019). In Europe, the genus Neoscona is represented by four species: Neoscona adianta (Walckenaer, 1872), Neoscona byzanthina (Pavesi, 1876), Neoscona subfusca (C.L. Koch, 1837) and Neoscona tedgenica (Bakhvalov, 1978). While N. adianta is abundant in all Europe and N. subfusca is present in the southern region of Europe, the distribution of N. byzanthina and N. tedgenica is restricted to France and Turkey, and southern European Russia, respectively. However, this last record has not been confirmed. Thus, of these species only N. adianta and N. subfusca have been reported to occur in the Iberian Peninsula (Nentwig et al., 2019).

According to Levi (1993) and Levy (1998), females of Neoscona differ from those in other genera by a curved, spatula-shaped epigynum with fused sclerites. The color pattern and shape of the opisthosoma, while reliable in one species, show great variation in another. In the case of the species occurring in the Iberian Peninsula, they can be easily distinguished: N. adianta has an oval opisthosoma, while N. subfusca shows an angular opisthosoma. Nevertheless, there has been a lot of controversy about the differentiation of N. byzanthina since it was described independently for the first time from Constantinople by Pavesi (1876) and Simon (1879). Simon (1884) put both descriptions in synonymy and later (Simon, 1929), pointed out that N. byzanthina might be only a local variety of N. adianta. The species was accepted in Bonnet´s catalogue (Bonnet, 1955), whereas Roewer (1955) considered that N. byzanthina is synonymous with N. adianta. Since then, N. byzanthina was not cited until Ledoux (2008) differentiated it from N. adianta. According to this author, N. byzanthina individuals are larger than N. adianta and the genitals size follows that difference in size between the two species. Opisthosoma design is more variable in N. byzanthina than in N. adianta. However, the first elongations of the bands are a little bit larger in N. adianta. In addition, the apical ends of the femurs are usually darker in N. byzanthina (Simon, 1929), and the hook of the epigynum has a triangular form in N. adianta, whereas in N. byzanthina it is more elongated and rounded. Also, the phenology of both species is different, since adults of N. adianta are frequent on June and July and adults of N. byzanthina are frequent on August and September.

The observations took place in late September and early October 2018, about 2.5 kilometers southeast from Olivenza (Badajoz, SW Iberian Peninsula). We found 10 female individuals which presented a dorsal abdominal pattern with discontinuous black bands. In some specimens the pattern was transformed into pairs of black and parallel points, each doubled by lighter points that characterize the species N. byzanthina (Fig. 1). In addition, a specimen was collected and analyzed in order to confirm the identity of the species. The result of the more detailed study of the female collected confirmed its assignment to N. byzanthina, following the criteria of Ledoux (2008). Also, we discovered that the observation of the epyginum structure in posterior view (Fig. 2) helps and completes the diagnosis of the species. The lateral pieces present in N. byzanthina are broader and longer than in N. adianta, in which the pieces are shorter and narrower, exposing the central area of the epigynum (Levy, 1998).

MATERIAL EXAMINEDTOP

1 ♀. Olivenza, Badajoz. 05/10/2018. UTM X: 667821,77. UTM Y: 4282339,45. Alt. 272 m. Open holm-oak dehesa. Carlos Mora-Rubio. 2018.

Thus, we provide the first data about the presence of N. byzanthina in the Iberian Peninsula. The habitat corresponds to an open holm-oak dehesa (a typical Mediterranean agro-forestry-pastoral ecosystem) of Quercus rotundifolia Lam., with a low load of bovine cattle (Datum: ETRS89; UTM X: 667821,77; UTM Y: 4282339,45; alt: 272 m) (Fig. 3).The specimens were sharing habitat with other araneids such as Argiope lobata (Pallas, 1772), an abundant species in the area; as well as Argiope trifasciata (Forskål, 1775), with a significantly lower occurrence (Mora-Rubio, 2018), and Cyrtophora citricola (Forskål, 1775), a frequent species in bushy holm-oaks. Unlike A. lobata, which appears in areas of greater density of scrubs and trees (since this araneid uses the lowest branches of the small holm-oaks as anchoring substrate of its web), N. byzanthina was only located on areas with a predominance of herbaceous plants, which were always used as the substratum for the elaboration of their web. In contrast to individuals observed by Ledoux (2008), which were located in humid areas because of the proximity of the sea, the climatic conditions of our study area are very different, characterized by long and dry summers with scarce rainfall.

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