Multi-loci phylogeny and morphological evidence support the recognition of Januaria (Spermacoceae, Rubiaceae), a new monospecific genus endemic to the North of Minas Gerais (Brazil)

NUÑEZ FLORENTIN, M.; FLORENTIN JAVIER E; SALAS, ROBERTO M.; DESSEIN, STEVEN; JANSSENS, STEVEN B.

ANAIS DA ACADEMIA BRASILEIRA DE CIENCIAS.

ACAD BRASILEIRA DE CIENCIAS

Año: 2023

0001-3765

Januaria is described as a new monospecific genus of Rubiaceae, based on material fromJanuária, northern Minas Gerais, Brazil. The new taxon is endemic to Brazil, occuring in avegetation type that is known locally as “carrasco”, in the southern limit of the Caatingabiome. Morphological (including palynological and SEM analyses) and molecularphylogenetic analyses based on nuclear (ETS, ITS) and plastid (atpB-rbcL, petD, rps16, trnL-trnF) sequence data were performed in the Spermacoce clade (tribe Spermacoceae).The molecular position and morphological features (a unique fruit dehiscence type, andpollen exine with simple reticulum) support Januaria as a new genus, with Mitracarpus assister group, from which it differs principally in calyx morphology, corolla shape, and fruitdehiscence. Additionally, a further comparison with other morphologically similar genera ispresented. We provide a formal description of Januaria, together with a distribution mapand comments on its conservation. In addition, a discussion about the Brazilian endemics ofthe Spermacoce clade is given, also with a key to all the genera of this group present in the country.