Zephronia Gray, 1832

Srisonchai, Ruttapon, Likhitrakarn, Natdanai, Sutcharit, Chirasak & Wesener, Thomas, 2024, Integrative taxonomy reveals two new giant pill-millipedes of the genus Zephronia Gray, 1832 from eastern Thailand (Diplopoda, Sphaerotheriida, Zephroniidae), ZooKeys 1212, pp. 29-64 : 29-64

Genus Zephronia Gray, 1832

Differential diagnosis.

Differs from all other genera of Zephroniinae by the combination of the following characters: 1) Body length 18–50 mm. 2) Antennae flattened laterally, usually axe-shaped, with numerous (> 4) apical cones. 3) Endotergum (tergite underside) weakly modified: posterior margin (pm) usually flat; outer area (os) without setae; marginal bristles arranged in 1–5 rows; middle area (ma) often with a single row of circular cuticular impressions. 4) Tarsi of legs 5–21 often with more than one apical spine (with very few species with only 1) and several ventral spines. 5) Anterior telopods with four podomeres distal to syncoxite; telopoditomere 2 with a large, curved process forming a clamp-like; telopoditomeres 3 and 4 simple. 6) Posterior telopods with four telopoditomeres; immovable finger (process of telopoditomere 2 slender, apically curved; telopoditomeres 3 and 4 with two membranous lobes; telopoditomere 3 also with a row of conspicuous, crenulated teeth, larger than elopoditomere 4; telopoditomere 4 with few (one or two) sclerotized spines. 7) Female vulvae conspicuous, slender; operculum usually round.

Zephronia is one of the most species-rich genera of the family with more than 50 species currently placed in the genus. Numerous species currently placed in the genus are in need of a revision, some only known from the female, and might be placed in separate genera in the future. The posterior telopod in Zephronia consists of four podomeres, unlike Castanotherium Pocock, 1895 whose species have three podomeres only. Podomere 4 of the posterior telopod in Zephronia is not strongly curved or overlapping the process of podomere 2 as in Cryxus Leach, 1814 . The process of podomere 2 in Zephronia is never apically enlarged or swollen like in Sphaerobelum Verhoeff, 1924 . The osterior telopod on podomere 3 in Zephronia has crenulated teeth, unlike Kophosphaera Attems, 1935 which lacks sclerotized teeth or spines entirely. The posterior telopod of Zephronia species is identical to those of species of Sphaeropoeus Brandt, 1833 , Prionobelum Verhoeff, 1924 , Tigridosphaera Jeekel, 2000 , and Indosphaera Attems, 1935 . Zephronia species differ from species of Sphaeropoeus and Prionobelum in the anterior telopods, lacking the characteristic processes on joints three ( Sphaeropoeus ) and four ( Prionobelum ). Zephronia species differ from Indosphaera in the coxae of leg 2 in females being separate, not fused. Zephronia species are currently impossible to distinguish from species of Tigridosphaera as that species-poor genus is in need of revision. Females of Zephronia differ in their shape of the operculum of the vulva from species of Indosphaera , where it is much lower than in Zephronia species, as well as from species of Sphaeropoeus and Prionobelum where the operculum is greatly enlarged and almost rectangular in shape.

Zephronia s. s.

Differing from all Zephronia s. l. by the position of the organ of Tömösváry, which is located at the brim and not inside the antennal groove as in all other known Sphaerotheriida . Zephronia s. s. includes the type species of the genus, Z. ovalis , as well as Z. chantaburiensis sp. nov., Z. chrysomallos , Z. dawydoffi , Z. erawani , Z. enghoffi , Z. golovatchi , Z. hui Liu & Wesener, 2022 , Z. konkakinhensis Semenyuk, Golovatch & Wesener, 2018 , Z. lannaensis , Z. laotica , Z. macula sp. nov., Z. medongensis Zhao & Liu, 2022 , Z. montis Semenyuk, Golovatch & Wesener, 2018 , Z. panhai , Z. siamensis and Z. zhouae Zhao & Liu, 2022 . See more details for the genus in Wesener (2016) and Semenyuk et al. (2018), and a recent update of Thai species in Bhansali and Wesener (2022).