Caerostris hirsuta
Creators: name: Gregorič, Matjaž
name: Yu, Kuang-Ping
name: Velez, Winny Rojas
name: Garb, Jessica E.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Araneidae
Caerostris
Caerostris hirsuta

description: Caerostris hirsuta (Simon, 1895)
Figs 1E, 5, 6D–F; Appendix 1
Trichocharis hirsuta Simon, 1895: 835 (♀).
Caerostris hirsuta – Grasshoff 1984: 756 (♀), fig. 4.
Diagnosis
Caerostris hirsuta differs from all known species of Caerostris by the lack of lateral prosomal projections (Figs 5A, E, 6D). The female copulatory openings in C. hirsuta (Figs 5E, 6F) are elliptical in shape and relatively larger than in all other Afrotropical species of Caerostris. The epigynal hooks in C. hirsuta (Figs 5E, 6F) are positioned anteriorly on the epigynal plate, resembling C. corticosa (Grasshoff 1984: fig. 26), C. vicina (Grasshoff 1984: figs 23–24), and C. linnaeus (Gregorič et al. 2015b: fig. 7d) from mainland Africa. As in C. corticosa and C. vicina, these hooks point posteriorly, but are narrow and short in C. hirsuta rather than narrow and long as in the other two species. In C. linnaeus the hooks are narrow and short as in C. hirsuta, but point laterally rather than posteriorly. In contrast to C. hirsuta, all other known species of Caerostris from Madagascar, as well as others from mainland Africa, have the epigynal hooks positioned medially on the epigynal plate rather than anteriorly, they are wide rather than narrow, and point laterally rather than posteriorly (Grasshoff 1984; Gregorič et al. 2015b).
Material examined
Material examined
MADAGASCAR • 1 ♀; Antsiranana Province, Marojejy National Park; lat. -18.8255, lon. 48.4349; 29. Mar. 2022; M. Gregorič, M. Kuntner, K.P. Yu and M. Bedjanič leg.; Cox1 not obtained; ARA7894; USNM • 1 ♀; Antsiranana Province, Marojejy National Park; lat. -14.437629, lon. 49.775602; 24. Mar. 2022; M. Gregorič, M. Kuntner, K.P. Yu and M. Bedjanič leg.; GenBank accession number PP403864; ARA7933; ZRC • 1 ♀; same locality, date, and leg. data as for preceding; Cox1 not obtained; ARA7987; ZRC • 1 ♀; same locality and leg. data as for preceding; 25. Mar. 2022; GenBank accession number PP403865; ARA7896; ZRC SAZU • 1 ♀; same locality, date, and leg. data as for preceding; GenBank accession number PP403866; ARA7985; ZRC SAZU • 1 ♀; same locality and leg. data as for preceding; 26. Mar. 2022; Cox1 not obtained; ARA7931; ZRC SAZU • 1 ♀; same locality, date, and leg.data as for preceding; Cox1 not obtained; ARA7928; ZRC SAZU.
Description
Female (ARA7894 from Marojejy National Park, Madagascar, Fig. 5A–E)
MEASUREMENTS AND COLORATION. Total body length 21.93. Prosoma 9.70 long, 9.09 wide, 5.36 high. Carapace and chelicerae dark reddish brown, covered with long and dense yellowish setae. Sternum 4.40 long, 3.86 wide, widest between coxae of second legs, dark brown and sparsely covered with yellowish setae. AME diameter 0.45, PME diameter 0.35, AME separation 0.57, PME separation 1.28, PME–PLE separation 3.54, ALE–PLE separation 0.12. Clypeus height 1.72. Appendages: palps dark reddish brown. All leg segments uniformly dark reddish brown. Leg I femur 8.41, patella 6.47, tibia 6.85, metatarsus 8.62, tarsus 3.19. Opisthosoma 18.11 long, 16.87 wide, 6.92 high. Base color of dorsum light brown, with a yellowish longitudinal band, covered with black spots, and with several small, pointy tubercules on anterior half and pair of large posterior tubercules, pointing posteriorly and protruding past the spinnerets. Venter brown with several dark brown and black spots, two paler, grey, longitudinal bands. Epigynum as diagnosed (Fig. 5E).
Variation
Female total length 21.93–23.30, prosoma length 8.71–9.70. Base color of opisthosoma dorsum light brown to dark brown, with anterior tubercules from small to pronounced. Some individuals with light median band, others without (Figs 5A, 6D).
Distribution
Toamasina (Tamatave), eastern Madagascar, is designated as the locality of the holotype. However, the species today does not occur in eastern Madagascar, and Toamasina as a major port-city was often designated as the locality in museum collections in the past. Therefore, the holotype might not have been collected there. This species is likely restricted to the northern wet montane forests of Madagascar.
Natural history
This species occurs in montane rainforests of northeastern Madagascar. The web is typical of Caerostris (Gregorič et al. 2011a), suspended at day and night.
description: Published as part of Gregorič, Matjaž, Yu, Kuang-Ping, Velez, Winny Rojas & Garb, Jessica E., 2025, Caerostris (Araneidae: Araneae) cryptic diversity highlights the need for taxonomic expertise in the genomic era, pp. 1-23 in European Journal of Taxonomy 989 on pages 11-12, DOI: 10.5852/ejt.2025.989.2877, http://zenodo.org/record/15303757