Genus Citharognathus Pocock, 1895 Citharognathus Pocock 1895: 179, 183; Waterhouse 1902: 77; Cytharognathus Simon 1903: 944, 946; Mello-Leitão 1923: 378; Petrunkevitch 1928: 84; Neave 1939: 747; Roewer 1942: 273; Bonnet 1956: 1096; Raven 1985: 116; Smith 1988: 104, 105. Type species. Citharognathus hosei Pocock, 1895, by monotypy. Etymology. Greek cithara κιθάρα, meaning an ancient Greek musical instrument in the lyre or lyra family and Greek gnathos γνᾰ́θος, Latinized into gnathus, meaning “jaw”, referring to the sound-producing lyra between the opposing faces of the chelicerae and maxillae. Diagnosis. Females differ from females of the other genera of Ornithoctoninae by having numerous short, stout black spinules on patella, tibia and metatarsus of leg III & IV (Figs 9C, 12A, 13B). Females differ from females of most ornithoctonine genera by having leg IV distinctly longer and thicker than leg I; tibia IV thickest; tibia IV wider than femur IV (except Magnacrus gen. nov.). Citharognathus can be distinguished from Cyriopagopus and Magnacrus gen. nov. by having spines above the suture of the coxa of palp (Fig. 10E). They can also be distinguished from Cyriopagopus by having fewer than 6 spines on metatarsus IV, and the males can be differentiated by having significantly weaker keels on the embolus than those in the Cyriopagopus (Fig. 11A–F). They can be distinguished from males of Ornithoctonus because they have a spine on tibia I v, a, rl (Fig. 10C–D), the keels on the embolus are significantly weaker than in Ornithoctonus and they have no notch on VTM (Fig. 11A–F). They can be distinguished from males of Taksinus by having a spine on tibia I v, a, rl (Fig. 10D) and the basal area of the embolus is significantly wider than in Taksinus: ERF between embolus thickness at the base in relation to embolus thickness in the middle of the embolus is 26 in Taksinus (40 in Citharognathus) (Fig. 11F). They can be distinguished from males of Phormingochilus and Omothymus by the basal area of the embolus which is significantly wider than in males of Citharognathus: ERF between embolus thickness at the base in relation to embolus thickness in the middle of the embolus is less than 32 in males of both genera (40 in Citharognathus) (Fig. 11F). Males of Citharognathus differ from Lampropelma males in that the apical embolus is not swollen (see Gabriel & Sherwood 2019) and the embolus in dorsal view emerges from the prolateral side of the tegulum (Fig. 11D, E). In Lampropelma males, the embolus emerges from the retrolateral side. Distribution. Malaysia (Borneo).

Published as part of Hoang, Quang Duy, Yu, Kun, Wendt, Ingo, West, Rick C. & Wirth, Volker Von, 2025, The new genus Magnacrus (Araneae: Theraphosidae: Ornithoctoninae) from Vietnam, with notes on Citharognathus hosei Pocock, 1895, pp. 351-381 in Zootaxa 5701 (3) on pages 369-370, DOI: 10.11646/zootaxa.5701.3.5, http://zenodo.org/record/17326120