Rangkayo perkaso Dhiya’ulhaq & Benjamin, 2025

Dhiya'ulhaq, Naufal Urfi, Benjamin, Suresh P., Buchori, Damayanti, Hidayat, Purnama, Scheu, Stefan & Drescher, Jochen, 2025, Expanding the taxonomy of crab spiders (Araneae, Thomisidae) in Sumatra: a new genus, five new species, and regional records, ZooKeys 1241, pp. 205-246 : 205-246

Rangkayo perkaso Dhiya’ulhaq & Benjamin sp. nov.

Figs 26 , 27 , 28

Type material.

Holotype. Indonesia – Jambi Province • 1 ♂; Sarolangun, Air Hitam, Lubuk Kepayang ; 02°03'46.6"S, 102°48'03.5"E; elev. 74 m; 26 Jun. 2013; J. Drescher leg.; canopy fogging in jungle rubber plantation; GOET 2013_BJ 3.2_AraThom 056 N_001 (to be transferred to MZB) . Paratypes. Indonesia – Jambi Province • 1 ♀; Sarolangun, Bukit Duabelas National Park ; 01°56'30.8"S, 102°34'50.6"E; elev. 91 m; 4 Oct. 2013; J. Drescher leg.; canopy fogging in rainforest; GOET 2013_BF 4.2_AraThom 056 N_001 (to be transferred to MZB) . • 1 ♂; Sarolangun, Air Hitam, Desa Baru ; 02°01'49.5"S, 102°46'14.8"E; elev. 57 m; 12 Jul. 2013; J. Drescher leg.; canopy fogging in jungle rubber plantation; GOET 2013_BJ 6.1_AraThom 056 N_001 (to be transferred to MZB) . • 1 ♂; Batang Hari, Hutan Harapan Conservation Area ; 02°09'09.3"S, 103°21'41.8"E; elev. 65 m; 19 Jul. 2013; J. Drescher leg.; canopy fogging in rainforest; ZMH ZMH -A 0031858 (GOET 2013_HF 1.1_AraThom 056 N_001) . • 1 ♂; Batang Hari, Bajubang, Sungkai ; 01°50'58.7"S, 103°18'00.5"E; elev. 56 m; 5 Jun. 2013; J. Drescher leg.; canopy fogging in jungle rubber plantation; GOET 2013_HJ 3.2_AraThom 056 N_001 (to be transferred to SMF) .

Diagnosis.

Males of Rangkayo perkaso Dhiya’ulhaq & Benjamin , sp. nov., can be easily distinguished from the only other species Rangkayo hitam Dhiya’ulhaq & Benjamin , sp. nov., by the conspicuously bent cymbium (Fig. 26 G ) (vs straight; Fig. 23 G ), the presence of dorsal cymbial setae with widened base (vs absent), larger, oval shaped tegulum, covering most of embolic base (Figs 26 D , 28 A vs smaller, round, not covering most of embolic base, Figs 23 D , 25 A ), a shorter, curved conductor (vs longer and straight), and large tegular bump (vs small). Females can be distinguished by the CO positioned closer together (Figs 27 C, E , 28 C ), the anterior region of the atrium narrower than the posterior region (vs both regions similarly wide; Figs 24 C, E , 25 C ). CD with a wider second loop, fully encircling the first loop (Figs 27 D , 28 B vs first loop being mostly outside the second loop, Figs 24 D , 25 B ), and the posterior part of CD forming a transverse bow (vs a longitudinal bow).

Description.

Male (holotype 2013_BJ 3.2_AraThom 056 N_001; Figs 26 , 28 A ). Total length 3.29. Carapace length 1.52; width 1.47. Abdomen length 1.77; width 1.25. Diameter of eyes: AME 0.04; ALE 0.10; PLE 0.12; PME 0.08. Interdistances between eyes: AME – AME 0.07; AME – ALE 0.05; ALE – ALE 0.24; PME – PME 0.13; PME – PLE 0.11; ALE – PLE 0.13; AME – PME 0.22; PLE – PLE 0.51. Leg measurements: leg I 9.99 (2.68, 0.52, 3.13, 2.65, 1.01); leg II 10.38 (2.85, 0.56, 3.23, 2.71, 1.03); leg III 4.46 (1.39, 0.34, 1.34, 0.92, 0.47); leg IV 4.93 (1.54, 0.34, 1.47, 1.05, 0.53). Carapace pear-shaped, yellow; eye region slightly darker; AER recurved; PER slightly recurved. Legs uniformly pale yellow. Abdomen oval; dorsally yellow with two full pairs of red spots and two smaller ones only on the left side; paired white spots very faint; laterally pale. Palp (Figs 26 D – F , 28 A ): cymbium more than 2 × longer than tibia, retrolaterally bent, elongated with a narrowed anterior extension; dorsally with a prominent hump in the centre, as well as two fields of setae with widened base. Tegulum large, oval-shaped, covering the embolic base. Tegular bump large, apically positioned. Conductor with a wide base, abruptly narrowed and strongly curved. Embolus long, whip-like, curving around the prolateral side of the bulb, before distally curving to the other direction. Tibia ventrally with seven strong macrosetae.

Female (paratype 2013_BF 4.2_AraThom 056 N_001; Figs 27 , 28 B, C ).

Total length 3.83. Carapace length 1.47; width 1.45. Abdomen length 2.36; width 1.73. Diameter of eyes: AME 0.05; ALE 0.11; PLE 0.13; PME 0.08. Interdistances between eyes: AME – AME 0.08; AME – ALE 0.05; ALE – ALE 0.26; PME – PME 0.13; PME – PLE 0.12; ALE – PLE 0.12; AME – PME 0.22; PLE – PLE 0.53. Leg measurements: leg I 7.81 (2.26, 0.39, 2.38, 1.85, 0.93); leg II -; leg III 4.09 (1.21, 0.35, 1.20, 0.84, 0.49); leg IV 4.62 (1.48, 0.34, 1.37, 0.92, 0.51). Female habitus as in male, except for the following: abdomen with four full pairs of red spots, interspersed with prominent white spots; laterally bordered by a thick white band. Epigynum (Figs 27 C – E , 28 B, C ): atrium large, butterfly-shaped; anterior region narrower than the posterior region. CO semicircular. CD very long and convoluted, anteriorly with two major loops; the first loop after the CO almost forms a full loop, completely encircled by the second loop. Next to the second loop is a straight tube running to the posterior. Posterior part of CD initiated by a slightly meandering tube, followed by a transverse bow, then a few folds and turns before ending in a rather inconspicuous, oval shaped spermatheca.

Etymology.

The specific epithet is taken from a Jambi Malay word meaning powerful, which is included in the first line of the traditional song from Jambi ‘ Orang Kayo Hitam’: Rang Kayo Hitam, gagah perkaso (translated: Rang Kayo Hitam, mighty and powerful). Also referring to the rather strong bend of the male palp.

Distribution.

Indonesia (Sumatra: Jambi Province) Fig. 29 .

Figures

Figure 23. Rangkayo hitam Dhiya’ulhaq & Benjamin, sp. nov., male (holotype 2013 _ HFr 1.2 _ AraThom 091 N _ 001) A, B habitus A dorsal view B ventral view C eye region, frontal view D – G right palp (mirrored) D prolateral view E ventral view F retrolateral view G dorsal view. Scale bars: 1 mm (A, B); 0.2 mm (C – G).

Figure 24. Rangkayo hitam Dhiya’ulhaq & Benjamin, sp. nov., female (paratype 2013 _ HJ 4.1 _ AraThom 091 N _ 001) A, B habitus A dorsal view B ventral view C – E epigynum C ventral view D cleared, ventral view E cleared, dorsal view. Scale bars: 1 mm (A, B); 0.1 mm (C – E).

Figure 25. Rangkayo hitam Dhiya’ulhaq & Benjamin, sp. nov. A, B male (holotype 2013 _ HFr 1.2 _ AraThom 091 N _ 001), right palp (mirrored) A ventral view B, C female (paratype 2013 _ HJ 4.1 _ AraThom 091 N _ 001), epigynum B ventral view C dorsal view. Abbreviations: AT = atrium; C = conductor; CD = copulatory duct; CO = copulatory opening; E = embolus; EB = embolic base; FD = fertilisation duct; L 1 = first loop of copulatory ducts; L 2 = second loop of copulatory ducts; MA = median apophysis; S = spermatheca; TB = tegular bump. Scale bars: 0.2 mm.

Figure 26. Rangkayo perkaso Dhiya’ulhaq & Benjamin, sp. nov., male (holotype 2013 _ BJ 3.2 _ AraThom 056 N _ 001) A, B habitus A dorsal view B ventral view C eye region, frontal view D – G left palp D prolateral view E ventral view F retrolateral view G dorsalview. Scale bars: 1 mm (A, B); 0.2 mm (C – G).

Figure 27. Rangkayo perkaso Dhiya’ulhaq & Benjamin, sp. nov., female (paratype 2013 _ BF 4.2 _ AraThom 056 N _ 001) A, B habitus A dorsal view B ventral view C – E epigynum C ventral view D cleared, ventral view E cleared, dorsal view. Scale bars: 1 mm (A, B); 0.1 mm (C – F).

Figure 28. Rangkayo perkaso Dhiya’ulhaq & Benjamin, sp. nov. A, B male (holotype 2013 _ BJ 3.2 _ AraThom 056 N _ 001), left palp A ventral view B, C female (paratype 2013 _ BF 4.2 _ AraThom 056 N _ 001), epigynum B ventral view C dorsal view. Abbreviations: AT = atrium; C = conductor; CD = copulatory duct; CO = copulatory opening; E = embolus; FD = fertilisation duct; L 1 = first loop of copulatory ducts; L 2 = second loop of copulatory ducts; MA = median apophysis; S = spermatheca; TB = tegular bump. Scale bars: 0.2 mm.

Figure 29. Distribution of examined Thomisidae species from the Epidius clade (sensu Benjamin, 2011) prior to the present study, as well as the sampling location of the current study in Jambi Province, Sumatra, Indonesia (green flag). The new genus and the five new species described in the present study are all from the same study location, i. e., a replicated plot design across lowland rainforest, ‘ jungle rubber’ (rubber agroforestry), and smallholder monoculture plantations of rubber and oil palm in Jambi’s lowlands (Drescher et al. 2016).