It is very tiny and was one of seven new species described by LF Ribeiro and a team of scientists from the Mater Natura - Instituto de Estudos Ambientais in Brazil.

Like all species in its genus, it is found in a very small strip of Atlantic Forest in the southeastern coast of the country, and has a vibrant colour pattern.

[1] The speciation seen in this genus is thought to be a byproduct of the rift between the valley versus mountain terrain and its particular microclimates, to which they are adapted.

This species is distinguished from its cogenerates by possessing a robust and bufoniform body, the adult average length between 9.7 to 12.4 millimetres (0.38 to 0.49 in); its rough dorsum; and general coloration being predominantly yellow, with a stripe along its vertebral column varying from a dark brownish colour to black.

[1] Brachycephalus fuscolineatus is only known from its type locality, in Morro do Baú in the State of Santa Catarina at 680 metres (2,230 ft) above sea level.