Phylogeny, ratification of recognized taxa, and determination of new cryptic taxa in brocket deer (Cervidae, Artiodactyla) using mitochondrial DNA: a surprising genetic diversity revealed in many new possible taxa

Abstract

Brocket deer (Cervidae, Artiodactyla) constitute one of the most systematically complex groups of mammals due to their chromosomal fragility, which favors rapid speciation processes through reproductive isolation barriers, and because they represent a case of extreme morphological convergence in the mammalian world. In recent years, new genera have been distinguished in gray brocket deer (Subulo, Passalites, Bisbalus) and new genera and species in red brocket deer (Andinocervus rufinus, Mazama reperticia, Mazama zetta, Mazama tschudii, Odocoileus pandora). In the present study, we analyzed three databases with mitochondrial DNA sequences. In the first database (DB1), 157 Neotropical deer (including 120 brocket deer) were analyzed for two mitochondrial genes (mtND5 and mt12S rRNA); In the second database (DB2), 141 Neotropical deer (including 91 brocket deer) were analyzed for the mtCyt-b gene, and in the third database (DB3), 72 Neotropical deer (including 50 brocket deer) were studied for their complete mitogenomes. Some of the main results obtained are as follows: 1- The existence of the new brocket deer genera proposed in recent years (Subulo, Passalites, Bisbalus, Andinocervus) was confirmed; 2- The presence of Subulo gouazoubira in the Bolivian and Colombian Andes was confirmed (or at least, the presence of specimens carrying the mtDNA of S. gouazoubira); 3- The presence of a possible new taxon related to S. gouazoubira was detected in the Bolivian Amazon, and another possible new taxon related to Subulo chunyi was detected in the Bolivian Andes. 4- Within Passalites nemorivagus, at least two taxa were detected. Two specimens with phenotypes differentiated from those of P. nemorivagus, related to this species, were also detected, one in the Colombian Amazon and the other on the Ecuadorian Pacific coast, which may constitute new taxa of gray brocket deer. 5- Bisbalus citus was originally located in Venezuela. Here we report the presence of B. citus along the northern coast of Colombia (Bolívar, Cesar, and Magdalena departments), thus constituting the first record of this species for this country; 6- Mazama rufina (Andinocervus rufinus) showed that its original mitochondrial radiation occurred in the present-day Ecuadorian Andes, and there is possibility that at least two taxa exist within it; 7- The phylogenetic position of Mazama (Odocoileus) pandora varied depending on the database used and the different procedures employed, therefore studies with nuclear markers are required to precisely delimit its position; 8- It was confirmed that, as shown in a previous study, the Mazama temama complex is possibly composed of three different species. The origin of this complex was detected in the present-day Chocó region of Colombia. Also, for the first time, the presence of a taxon of the M. temama complex was detected molecularly in Ecuador; 9- Nevertheless, the Mazama americana complex presented the most complex taxonomic and systematic situation. Eight distinct groupings were detected within this complex (M. americana I, II-III, IV, V, VI, VII, and VIII), five of them new to science. Some of these contained significant subgroups that could constitute new brocket deer taxa (M. americana IV, V, and VII). 10- With all this, we detected and geographically indicated at least 16 groups of brocket deer that require karyotypic studies especially since they could constitute new genera, species and subspecies of brocket deer not yet determined by science.