Racata laxa, Tanasevitch, 2019

Tanasevitch, Andrei V., 2019, On the spider genus Racata Millidge, 1995, with the description of three new species (Araneae, Linyphiidae), Revue suisse de Zoologie 126 (1), pp. 53-59 : 58-59

Racata laxa sp. nov.

Figs 9-13 , 26

Holotype: Female [Sum-06/05]; INDONESIA, Sumatra, West Sumatra Province, Batang Palupuh Rafflesia Sanctuary , 12 km N of Bukittinggi, 0°14’32”S, 100°21’10”E, 900-1100 m a.s.l., primary forest; 2.-3. VI.2006; leg. P. Schwendinger.

Paratypes: 5 females [Sum-06/01]; collected together with the holotype . – 3 females; West Sumatra Province, old secondary forest above Taman Hutan Raya Bung Hatta, near road from Padang to Lubuksulasih , 0°56’45”S, 100°32’37”E, 1100 m a.s.l.; 29.-30. V.2006; leg. P. Schwendinger. – 1 female [Sum-06/03]; Anai Valley , 6 km S of Padangpanjang , 0°28’38”S, 100°21’14”E, primary forest, 500 m a.s.l.; 1. VI.2006; leg. P. Schwendinger. – 5 females [Sum-06/20]; disturbed primary forest near road from Lubuksikaping to Bonjol , ca 10 km S of Lubuksikaping , 0°03’16”N, 100°12’33”E, 500 m a.s.l.; 12. VI.2006; leg. P. Schwendinger. – 1 female; Mt Singalang (= Mt Singgalang), Anai Valley , 400 -520 m a.s.l., secondary forest, leaf litter; 9.-24. VI.1994; leg. S. Djojosudharmo. – 2 females [Sum-06/22]; North Sumatra Province, Sipirok, Dolok Sipirok NP, near hot springs, about 30 km N of Padangsidempuan , 1°33’55”N, 99°17’03”E, disturbed hill forest, 1000 m a.s.l.; 16. VI.2006; leg. P. Schwendinger. – 1 female [AS-TH06/4]; THAILAND, Trat Province, Ko Chang, northern side, forest 3 km E of White Sand Beach , 50 -200 m a.s.l., 12.02527°N, 102.308333°E; 7.XI.2006; leg. A. Schulz.

Etymology: The specific name is a Latin adjective, meaning “wide, spacious”, referring the large epigynal cavity.

Diagnosis: The female of the new species is characterised by the specific shape of its large epigyne, namely, by the two loops of the copulatory ducts, which are visible through the translucent bottom the epigynal cavity.

Description: Female paratype from Anai Valley. Total length 1.58. Carapace 0.63 long, 0.55 wide, pale yellow, with indistinct radial stripes and narrow grey margin. Chelicerae 0.25 long. Legs pale yellow, almost white. Leg I 2.74 long (0.75+0.18+0.73+0.65+0.43), IV 2.51 long (0.73+0.15+0.65+0.58+0.0). TmI 0.28. Chaetotaxy: TiI: 2-1-1-0; II: 2-0-1-0, III-IV: 2-0-0-0; MtI-IV without spines. TmI 0.36. Length of spines 1.5-2 diameters of corresponding leg segment. Metatarsi IV without trichobothrium. Abdomen 0.95 long, 0.70 wide, pale grey, almost white. Epigyne ( Figs 9-13 , 26 ) with a large cavity surrounded by a sclerotized swelling; a pair of loops of the copulatory ducts, which are visible through the translucent cavity bottom.

Variability: The shape of the epigyne is slightly variable, see Figs 10-13 .

Taxonomic remarks: The species is only known by females but can be easily recognized by its very large epigynal cavity surrounded by a sclerotized swelling, and by a pair of loops of the copulatory ducts that can bee seen through the translucent cavity bottom.

Distribution: Known from several localities on Sumatra, Indonesia and from a locality on an island off the coast of eastern Thailand.

Figures

Figs 1-13. Racata grata Millidge, 1995 (1-4), R. brevis sp. nov., male holotype (5) and female paratype (6); R. sumatera sp. nov., male holotype (7) and female paratype (8); R. laxa sp. nov., female paratypes (9-13). (1, 5, 7) Male body, dorsal view. (2, 9) Female body, dorsal and ventral view, respectively. (3-4, 6, 8) Female abdomen, ventral view. (10-13) Epigyne, ventral view. Specimens from: near Cibodas (1-4), Mt Kerinci (5-6), Mt Sibayak (7-8), Bukittinggi (9, 12), Padangpanjang (10), Padangsidempuan (11), Taman Hutan Raya Bung Hatta (13).

Figs 23-26. Vulva structure (dorsal view) of Racata grata Millidge, 1995, specimen from near Cibodas (23); R. brevis sp. nov., paratype from Mt Kerinci (24); R. sumatera sp. nov., paratype from Mt Sibayak (25); R. laxa sp. nov., paratype from Bukittinggi (26).