Rangkayo 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 Dhiya’ulhaq & Benjamin gen. nov.

Type species.

Rangkayo hitam Dhiya’ulhaq & Benjamin , sp. nov.

Diagnosis.

Among the Oriental thomisids of the Epidius clade (sensu Benjamin 2011), Rangkayo Dhiya’ulhaq & Benjamin , gen. nov., is similar to Epidius Thorell, 1877 and Ibana Benjamin, 2014 in possessing a row of strong macrosetae ventrally on the distal edge of male palpal tibia and the lack of MA, but can be distinguished from both genera by the shape of cymbium with a prominent apical protrusion and presence of tegular bump. Additionally, it is distinguished from Epidius by the long, whiplike embolus and tibia shorter than cymbium and from Ibana by the larger conductor with a wide base. The tibia of the two described species lack TA, a feature also absent in some species of the other two genera ( Ibana gan Liu & S. Q. Li, 2022 ; Epidius mahavira Benjamin, 2017 b ; Epidius longimanus Benjamin, 2017 b ). Females are unique in having a large, butterfly shaped atrium; very long, convoluted CD arranged in loops, turns, and folds; small, inconspicuous spermatheca. The latter two characters appear instead superficially similar to the dietine genus Lycopus Thorell, 1895 .

Description.

Total body length 3–4 mm. Carapace pear-shaped, slightly longer than wide. PLE> ALE> PME> AME. AER recurved, PER slightly recurved. Legs long and slender; front legs much longer than back legs; leg formula 2143; tarsi and tibiae I and II with several pairs of ventral spines. Abdomen oval. Male palp: cymbium elongated, with an apical extension; embolus very long, whip-like, arising from an extension of the tegulum; conductor present; tegular bump present, situated next to the conductor; tibia ventrally with a row of macrosetae. Epigynum: Atrium large, butterfly-shaped; copulatory ducts very long and convoluted, consisting of loops, turns, and fold; spermatheca small and inconspicuous. Colouration: whole body yellow; eye region slightly darker; abdomen with several pairs of red and white spots dorsally. Hardly any somatic difference between sexes.

Etymology.

The generic name, as well as the type species, is taken from Rangkayo Hitam or Orang Kayo Hitam, a legendary king of Jambi central to the foundation myth of Jambi City. Gender masculine.

Species composition.

Rangkayo hitam Dhiya’ulhaq & Benjamin , sp. nov., Rangkayo perkaso Dhiya’ulhaq & Benjamin , sp. nov.