Ummeliata jambi, Tanasevitch, 2020

Tanasevitch, Andrei V., 2020, Two new linyphiid species from Borneo and Sumatra (Araneae: Linyphiidae), Raffles Bulletin of Zoology 68, pp. 473-478 : 475-476

Ummeliata jambi , new species

( Figs. 2–6 , 14–20 )

Holotype. Male ( MHNG), INDONESIA, Sumatra, Jambi, Mt Kerinci , 2,500 m a.s.l., sifting vegetation debris in moss forest; 12 November 1989, coll. D. Burckhardt, I. Löbl and D. Agosti [14].

Paratype. 1 female ( MHNG), collected together with the holotype.

Diagnosis. Ummeliata jambi , new species, is characterised by a highly reduced mastidion on the chelicera, the distal apophysis of the convector in males well protruding forward, and by the deeper notch on the anterior wall of the epigyne in females. The species seems to be especially similar to U. insecticeps ( Bösenberg & Strand, 1906) , which occurs in southern Siberia, the Russian Far East, Korea, Japan, China (including Taiwan), and northern Vietnam ( Tu & Li, 2004). The male of the new species is easily distinguishable from the larger postocular elevation, the highly reduced mastidion, the reduced radix, as well as the distal apophysis of the convector well protruding forward. The female differs by the deeper notch on the anterior wall of the epigyne and the absence of a tubercle at the bottom of the notch. The distal apophysis of the convector protruding from the palp in U. jambi , new species, resembles that of U. xiaowutai Han & Zhang, 2014 (termed by the authors as the anterior radical process), known from northeastern China ( Han & Zhang, 2014). However, the shapes of the distal apophysis of the convector and other parts of the palp are different in both species.

Etymology. The specific epithet is a noun in apposition referring to its type locality, the Jambi province of Sumatra.

Description. Male holotype. Total length 2.03. Carapace modified: middle part of carapace with a rounded elevation separated from cephalic part by a deep slit (as in Figs. 2–4 ), 1.00 long, 0.75 wide, greyish brown with indistinct radial stripes. Eyes normal, not enlarged. Chelicerae 0.38 long, mastidion highly reduced. Legs pale brown. Leg I 2.71 long (0.75 + 0.25 + 0.63 + 0.60 + 0.48), IV 2.89 long (0.75 + 0.25 + 0.73 + 0.68 + 0.48). Chaetotaxy: 2.2.1.1. Length of spines 1–2 diameters of corresponding leg segment. TmI 0.68–0.69. Metatarsi I–IV each with a trichobothrium. Palp ( Figs. 14–19 ): Tibia slightly elongated, with a small tubercle apically. Paracymbium narrow, L-shaped, with a blunt tooth in middle part. Tegulum distally bearing a small, almost transparent, poorly visible protegulum. Distal suprategular apophysis relatively short, rounded. Median membrane reduced. Convector very large, V-shaped, its distal apophysis well protruding forward. Radix reduced, embolus coiled, with a membranous edge. Abdomen ( Fig. 2 ) 1.18 long, 0.78 wide, dark grey.

Female paratype. Total length 2.25. Carapace unmodified (as in Fig. 5 ), 0.95 long, 0.78 wide, greyish brown with indistinct radial stripes. Eyes normal, not enlarged. Chelicerae 0.38 long, mastidion absent. Legs brown. Leg I 2.49 long (0.68 + 0.25 + 0.60 + 0.53 + 0.43), IV 2.72 long (0.78 + 0.25 + 0.68 + 0.63 + 0.38). Chaetotaxy: 2.2.1.1. Length of spines 1–2 diameters of corresponding leg segment. TmI 0.75. Metatarsi I–IV each with a trichobothrium. Abdomen ( Figs. 5, 6 ) 1.43 long, 1.00 wide, dark grey. Epigyne ( Figs. 6 , 20 ): Anterior wall (= ventral plate, auct.) with a deep and rounded notch. Receptacles spherical.

Distribution. Known only from the type locality in Sumatra, Indonesia.

Figures

Figs. 1–6. Pseudomicrocentria uncata, new species, male paratype (1), Ummeliata jambi, new species, male holotype (2–4) and female paratype (5–6). 1–2, male body, dorsal view; 3–4, male prosoma, lateral and frontal views, respectively; 5, female body, dorsoventral view; 6, female abdomen, ventral view. Scale = 0.5 mm.

Figs. 14–20. Details of male palp structure of Ummeliata jambi, new species, male holotype (14–19) and female paratype (20). 14–15, right palp, retro- and prolateral views, respectively; 16, palpal tibia and paracymbium, lateral view; 17, palpal tibia, dorsal view; 18, distal suprategular apophysis and part of embolus, lateral view; 19, embolic division, frontal view; 20, epigyne, ventral view. Scale = 0.1 mm.