Baiyuerius
Baiyuerius is a genus of spiders in the family Agelenidae, subfamily Coelotinae. The genus was described in 2023 and contains 24 species distributed across southern China and northern Vietnam.
Etymology
The generic name is derived from the pinyin word "Baiyue", referring to the Baiyue region where the genus is distributed. Baiyue was a term dating back to the first millennium BC, used to denote various populations who inhabited southern China and northern Vietnam. The postfix "-rius" refers to the postfix commonly used in the genera of the Sinodraconarius clade.Description
Medium-sized spiders with total lengths ranging from 8.60 to 11.98 mm. The cephalothorax is black turning brown or brown turning yellow-brown, pear-shaped, with longitudinal fovea and darker radial grooves. The chelicerae are the same color as the anterior carapace, with three promarginal and two retromarginal teeth. The endites and labium are dark brown or grey, anteriorly white with black hairs. The sternum is brown or milk-white, longer than wide. The opisthosoma is yellow-brown, covered with grey hairs, with two pairs of apodemes and four darker chevron-like markings.The leg formula is 4123. In males, the pedipalp femur is more than three times longer than the patella, with the patella approximately half the length of the tibia. The patellar apophysis is thick and enlarged, finger-like, longer than half of the tibia and extending over the patella. The cymbial base is enlarged with one or two hypophyses, and the embolus is widened and slightly elongated, being widest anteriorly.
Females lack epigynal teeth. The atrium is located anteriorly, over the swell of the epigyne, internally milk-white, occupying more than or equal to one-quarter of the female epigyne. The spermathecae are small and located posteriorly, shorter than one-quarter the length of their copulatory ducts, with the anterior part fist-like and bases close to each other.