Colubrid snakes of the genus Chironius comprise 21 currently recognized species widely distributed in Central and South America. These snakes, often called sipos (from the Portuguese word cipó for liana) are not venomous and are mostly harmless.
The species name "brazili" honors Vital Brazil Mineiro da Campanha (1865–1950), a Brazilian scientist who discovered the specificity of snakebite serum and developed antiserum to treat bites of several venomous snakes of different genera. He also founded two centers of excellence in research and production of strategic biological products for public health in Brazil.
For the experts: We conducted a taxonomic review of Chironius flavolineatus on the basis of continuous and discrete morphological characters. We recognize a new species which is distinguished from all currently recognized congeners by the following unique combination of characters: first third of body black or dark gray; vertebral stripe yellowish or creamish white distinct from dorsals of nape and extending throughout almost whole body length; head dorsum tan to brown, distinct from background color of first third of body; posterior temporal scales ranging one to four; cloacal shield frequently divided; two to four rows of keeled dorsal scales at midbody; venter ground color gradually darkening towards cloaca; region of medial constriction of hemipenis slightly covered with spinules separating calyces of apex from spines below region of constriction; in lateral view, sulcus spermaticus positioned on convex face of hemipenis; ascending process of premaxilla oblique anteroposteriorly to longitudinal axis of skull; optic fenestrae not exceeding frontoparietal suture; posterior border of supratemporal exceeding braincase; dorsoventral axis of quadrate oblique mesolaterally, moving away from longitudinal axis of skull. Furthermore, we provide data on morphological variation, distribution, and an emended diagnosis for C. flavolineatus.