Brignoliella tao Ballarin & Yamasaki, 2021

Ballarin, Francesco, Yamasaki, Takeshi & Su, Yong-Chao, 2021, A survey on poorly known rainforest litter-dwelling spiders of Orchid Island (Lanyu, Taiwan) with the description of a new species (Araneae: Linyphiidae Tetrablemmidae, and Theridiosomatidae), Zootaxa 4927 (2), pp. 197-208 : 198-201

Brignoliella tao Ballarin & Yamasaki sp. nov.

Figs.1A ̅H, 2A̅C.

Type material. Holotype Ƌ: TAIWAN: Taitung County, Orchid Island (Lanyu), Hongtou neighborhood, elev. 270 m a.s.l., (22°00’59.1”N, 121°34’20.5”E), rainforest litter, 13. JUNE.2019, Ballarin F. leg. (NMNS-8309-001) . Paratypes: TAIWAN: 8³³, 18♀♀, same locality and date as the holotype, (NMNS-8309-002); 3³³ , 4♀♀, along the trail to Datianchi lake († R ¨), elev. 106 m a.s.l., (22°00’46.2”N, 121°34’13.9”E), rainforest litter, 13. JUNE.2019, ( MSNV, MSNVRAr006–012); 2³³ , 13♀♀, Hongtou forest , walking trail under a bridge, Elev. 68 m a.s.l., (22°00’34.8”N, 121°34’26.1”E), rainforest litter, 17. JUNE.2019, (NSMT-Ar 20876, Ar 20877). All Ballarin F. leg.

Other material examined. TAIWAN: 2♀♀, Taitung County, Orchid Island (Lanyu), Langdao neighborhood, near the Lanyu lighthouse, elev. 200 m a.s.l., (22°04’53.2”N, 121°30’17.7”E), rainforest litter, 17. JUNE .2019, ( NMNS); 2³, 3♀♀, near the Xiaotianchi Lake (ṮR¨), elev. 160 m a.s.l., (22°04’39.7”N 121°30’35.8”E), rainforest litter, 17. JUNE .2019, ( NSMT); 11³³, 11♀♀, Dongqing neighborhood, elev. 50 m a.s.l., (22°01’42.5”N, 121°34’36.4”E), rainforest litter, 14. JUNE .2019, ( FBPC); 5³³, 3♀♀, same locality, elev. 40 m a.s.l., (22°01’47.6”N, 121°34’30.3”E), rainforest litter, 15. JUNE .2019, ( NMNS). All Ballarin F. leg.

Etymology. The specific name refers to the Tao people, an ethnic group native of Orchid Island. Noun in apposition.

Diagnosis. Males of the new species can be easily distinguished from congeners by the shape of the two clypeal horns which are well-separated, short, rectangular, and ending with a blunt tip. In contrast, males of all other congeners have a different number of horns (e.g. B. delphina Deeleman-Reinhold, 1980 , B. ratnapura Shear, 1988 , B. trifida Lehtinen, 1981 ) or longer (e.g. B. dankobiensis Bourne, 1980 ), more pointed (e.g. B. acuminata (Simon, 1889) , B. besuchetiana Bourne, 1980 , B. bicornis (Simon, 1893) , B. carmen Lehtinen, 1981 , B. massai Lehtinen, 1981 , B. maros Lehtinen, 1981 ), and sometimes partially-fused horns ending with a sharp tip (e.g. B. besutensis Lin, Li & Jäger, 2012 , B. caligiformis Tong & Li, 2008 , B. maoganensis Tong & Li, 2008 , B. martensi (Brignoli, 1972) , B. michaeli Lehtinen, 1981 , B. patmae Fardiansah & Dupérré, 2019 , B. vulgaris Lehtinen, 1981 ). Males of B. tao sp. nov. can be further separated from males of the similar B. carmen from Philippine and B maros from Indonesia by the different shape of the embolus, larger and weaved rather than strait in B. carmen or much shorter and thinner in B. maros (see Fig 1A, B vs. figs. 113, 116 in Lehtinen, 1981). In addition, males of the new species can be further distinguished from males of other Chinese species ( B. maoganensis and B. caligiformis ) by the oblong, dorsoventrally flattened bulb of the palp in B. tao sp. nov., in contrast with a pear-shaped bulb as in the other Chinese species (see Fig. 1A, B vs. fig. 2F, G and fig. 3F, G in Tong & Li 2008). Female B. tao sp. nov. can be distinguished from female B. caligiformis , B. carmen , B. maoganensis , and B. maros by the rounder seminal receptacula, and especially by the position of anterolateral grooves of the preanal plate, close to each other near the center of the plate in the new species in contrast with more separate grooves at the sides of the plate in the latter species (see Fig. 2A, C , vs. figs. 2E, 3E in Tong & Li 2008 and figs. 121, 125 in Lehtinen, 1981).

Description. Male. (holotype). Measurements: total length: 1.55 carapace: 0.78 long, 0.61 wide.

Habitus as in Fig. 1E, F . Carapace uniformly dark reddish-brown, strongly sclerotized with a rugose and indented margin. Cephalic area strongly elevated, with a ring of nodular bumps starting from the ocular area and surrounding the margin of the raised part. Six eyes well-developed and all of the same size. Clypeal horns rectangular and stumpy with a trapezoidal shape when observed dorsally, ending with a squared tip. Chelicerae as in Fig.1 H , dark reddish-brown, bearing a well-developed front-mesial cheliceral apophysis, long and sharp, headed inward. Cheliceral lamina well-developed. Labium subtriangular, sternum with several bumps both colored as the carapace. Legs uniformly yellowish-brown. Leg measurements: I: (1.42) 0.47, 0.14, 0.35, 0.25, 0.21; II: (1.37) 0.44, 0.15, 0.31, 0.23, 0.24; III: (1.19) 0.34, 0.14, 0.26, 0.22, 0.23; IV: (1.51) 0.46, 0.14, 0.35, 0.29, 0.27. Opisthosoma uniformly dark reddish-brown. Dorsal and pulmonary scuta of opisthosoma with several sparse, small pits. Postgenital scutum present, often partially covered by other ventral scuta. Preanal and anal scuta rectangular and smooth, uniformly reddish, lighter-colored than other ventral scuta. Spinnerets reddish-brown.

Palp as in Fig. 1A ̅C. Femur bearing several spine pits ventrally, tibia bent, cymbium short and triangularshaped when seen laterally. Bulb oblong and compressed dorso-ventrally, bearing a seta in the posterior-ventral side. Spermatic duct with a simple course; embolus strongly sclerotized, long and lightly curved, ending with a sharp tip.

Female (one of the paratypes). Measurements: total length: 1.45; carapace: 0.70 long, 0.58 wide.

Habitus as in Fig. 1G, H . General coloration, and shape of prosoma and opisthosoma as in the male. Prosoma lacking clypeal horns. Leg measurements: I: (1.38) 0.45, 0.12, 0.34, 0.23, 0.24; II: (1.13) 0.35, 0.10, 0.26, 0.23, 0.19; III: (1.26) 0.38, 0.13, 0.30, 0.22, 0.23; IV: (1.49) 0.45, 0.14, 0.37, 0.29, 0.24.

Genitalia as in Fig. 2A ̅C. Epigynal fold distinct, anterolateral groves easily visible, close to each other in the central part of the preanal scutum. Vulval stem sclerotized. Vulval ducts starting at the side of the vulval stem, straight and connecting to translucent, round seminal receptacula.

Habitat. Humid leaf litter of the rainforest covering the mountain slopes of the island with an altitudinal range of approx. 40̅ 300 m a.s.l. Brignoliella tao sp. nov. appears to be absent in other habitats in the coastal areas. Distribution. Endemic to Orchid Island, widespread along the island ( Fig. 7 ).

Figures

FIGURE 1. Brignoliella tao sp. nov.: A. male palp, prolateral view; B. ditto, retrolateral view; C. ditto, ventral view; D. male chelicerae, frontal view; E. male habitus, dorsal view; F. ditto, lateral view; G. female habitus, dorsal view; H. ditto, lateral view. Abbreviations: b = palpal bulb; ca = cheliceral apophysis; cl = cheliceral lamina; e = embolus; pbs = palpal bulb seta.

FIGURE 2. Brignoliella tao sp. nov. A female opisthosoma, ventral view; B female genital area after maceration, ventral view; C ditto, dorsal view. Abbreviations: alg = anterolateral grove of preanal scutum; as = anal scutum; pls = pulmonary scutum; prs = preanal scutum; ps = postgenital scutum; sr = seminal receptaculum; vd = vulval duct; vs = vulval stem.

FIGURE 7. Map of Orchid Is., red dots show the localities where the species discussed in the text were collected: Brignoliella tao sp. nov. (1, 3̅7); Gongylidioides angustus Tu & Li, 2006 (1̅7); Theridiosoma triumphale Zhao & Li, 2012 (3, 4, 6); Zoma taiwanica (Zhang, Zhu & Tso, 2006) comb. nov. (1̅3, 5̅7).