Its original epithet was "Sauromalus obesus"; although that name is no longer officially recognized, it is still very common in the literature and it remains in many standard natural history references for North America. In 1998, Bradford D. Hollingsworth examined variations in "Sauromalus" and concluded that only five species should be recognized. He regarded "S. obesus" as conspecific with "S. ater", and he used "S. ater", which has priority, as the specific name of the combined taxon. No subspecies of "S. ater" are currently recognized. Based primarily on the extensive use of the name "S. obesus", a petition to give that name precedence over that of "S. ater" was submitted to the ICZN. However, this reasoning was dubious and the priority of "S. ater" was maintained. In 2004, ICZN ruled that the name "Sauromalus ater" was first described by zoologist Auguste Duméril in 1856, thus had precedence over the name "Sauromalus obesus" which was not named until 1858 by Baird.