Chironius is a genus of New World colubrid snakes, commonly called sipos (from the Portuguese word cipó for liana), savanes, or sometimes vine snakes. There are 23 described species in this genus. Species The following 23 species are recognized as being valid. Chironius bicarinatus (Wied, 1820) – two-headed sipo Chironius brazili Chironius carinatus (Linnaeus, 1758) – machete savane Chironius challenger Kok, 2010 Chironius diamantina Chironius exoletus (Linnaeus, 1758) – Linnaeus' sipo Chironius flavolineatus (Boettger, 1885) – Boettger's sipo Chironius flavopictus Chironius foveatus Bailey, 1955 Chironius fuscus (Linnaeus, 1758) – brown sipo Chironius gouveai Entiauspe-Neto, Lúcio-Lyra, Koch, Marques-Quintela, Diesel-Abegg, & Loebmann, 2020 – Gouvea's sipo Chironius grandisquamis (W. Peters, 1869) – Ecuador sipo Chironius laevicollis (Wied, 1824) – Brazilian sipo Chironius laurenti Dixon, Wiest & Cei, 1993 Chironius leucometapus Chironius maculoventris Chironius monticola Roze, 1952 – mountain sipo Chironius multiventris Schmidt & Walker, 1943 – long-tailed machete savane Chironius quadricarinatus (F. Boie, 1827) Chironius scurrulus (Wagler, 1824) – smooth machete savane Chironius septentrionalis Dixon, Wiest & Cei, 1993 Chironius spixii Chironius vincenti (Boulenger, 1891) – St. Vincent blacksnake Nota bene: A binomial authority in parentheses indicates that the species was originally described in a genus other than Chironius. Etymology The specific names, brazili and spixii, are in honor of Brazilian herpetologist Vital Brazil and German biologist Johann Baptist von Spix, respectively. Conservation status The St. Vincent Blacksnake, Chironius vincenti is listed as critically endangered by the IUCN Red List due to its extremely limited range on the Island of St. Vincent. References Further reading Fitzinger LI (1826). Neue Classification der Reptilien nach ihren natürlichen Verwandtschaften. Nebst einer Verwandtschafts-tafel und einem Verzeichnisse der Reptilien-Sammlung des K. K. zoologischen Museum's zu Wien. Vienna: J.G. Heubner. five unnumbered + 67 pp. + one plate. (Chironius, new genus, p. 60). (in German and Latin). Freiberg M (1982). Snakes of South America. Hong Kong: T.F.H. Publications. 189 pp. . (Chironius, pp. 30, 64, 92). Torres-Carvajal O, Echevarría LY, Lobos SE, Kok PJR (2018). "Phylogeny, diversity and biogeography of Neotropical sipo snakes (Serpentes: Colubrinae: Chironius)". Molecular Phylogenetics and Evolution 130: 315–329. Colubrids Snake genera Taxa named by Leopold Fitzinger