The grouping has a confused taxonomic history with the correct placement and spelling of type species M. ramirezia source of confusion for several decades prior to the publication of Kullander (2011). It was described as a member of the genus Apistogramma but later affiliated with the name Microgeophagus in an aquarium book by Hans Frey (1957) who did not provide diagnostic characters and only suggested it might be placed into that genus in the future.
The latter name did not achieve general acceptance until 1971 when Axelrod used it in a popular book about breeding aquarium fishes, although Klee (1971) rejected this and suggested that the species should instead be included in Geophagus. Kullander (1977) described the new genus Papiliochromis with P. ramirezi as type species, and in the same paper considered Microgeophagus to be an unavailable name without providing precise detail as to why.
Papiliochromis was accepted in both hobbyist and scientific literature until Bailey and Robins (1982) concluded that Microgeophagus sensu Axelrod (1971) was the oldest available name for a cichlid genus with A. ramirezi as type species, and thus should be considered valid.
Géry (1983, 1986) argued that Microgeophagus sensu Frey (1957) is the oldest available name for the genus, while Allgayer (1985) considered Papiliochromis valid. Kullander (1998) used Mikrogeophagus, a name he considered the oldest available based on its inclusion as a valid name in Jeg har akvarium, a Danish language aquarium book published in 1968, with Microgeophagus sensu Frey (1957) an unavailable nomen nudum lacking both a diagnosis and type species.
The genus Mikrogeophagus is thus attributed to Jens Meulengracht-Madsen, 1968, who authored the relevant sections in the book (it was edited by Schiøtz and Christensen), but it is considered an ‘involuntary’ nomenclatural act because the author believed he was using an existing name.
Mikrogeophagus therefore became widely-accepted following Kullander (1998), although a number of authors evidently did not agree.
After a period of inactivity Isbrücker (2011) re-opened the issue and argued that Microgeophagus sensu Frey (1957) is actually the oldest available name for the genus, but this was definitively rejected by Kullander (2011) who published a detailed analysis of the different generic names that have been used for the species, the majority of which were derived from aquarium, rather than scientific, literature.
Although Mikrogeophagus is now generally accepted to be correct the species M. ramirezi commonly appears in older aquarium literature as Apistogramma ramirezi, Microgeophagus ramirezi, or Papiliochromis ramirezi.
