"Morphologically, it differs from Astronotus crassipinnis and Astronotus ocellatus in pre-orbital depth, caudal peduncle depth, head width, and caudal peduncle length, with significant differences in average percentage values. Osteologically, it differs from the two described species by lacking a hypurapophysis on the parahypural bone (hypural complex) and having two or three supraneural bones. Another characteristic that helps diagnose the new species is the morphology of the sagitta otolith, which is oval with crenulated dorsal and ventral margins and a rounded posterior edge. Genetically, the new species is distinct from all the other lineages previously proposed for the genus, delimited by five single locus species delimitation methods, and also has unique diagnostic nucleotides. Phylogenetic analyses support the monophyly of the new species as well as all other species/lineages. Astronotus species have considerable genetic, anatomical, and sagitta otolith shape differences, but have few significant traditional morphometric and meristic differences, because there is high variability in counts of spines, soft dorsal-fin rays, and lateral-line scales. It is clear that this new species is genetically and anatomically differentiated from all other species within the genus, and deserves recognition as a new valid species."
People still use the term bumblebee oscar in regards to crassipinnis, because orbicularis is crassipinnis. Therefore the common name comes with it as a synonym. There is also a possibility that the ones being sold as bumblebee oscars under the name crassipinnis are from locales formerly known as orbicularis. As for the crassipinnis/"orbicularis" resembling mikoljii, I personally don't think they do at all. I turn back to TUIC for this one, I believe he has the best picture of them full grown online. Rusty Wessel has one adult that looks exactly like the one in this picture.
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I haven't kept crassipinnis yet, but have friends who have; crassipinnis is darker with more/more prominent stripes, mikoljii is more of a muted brown with some warped patterns. The main trademark I see of the species is the rows of dotted red scales along the abdomen. Mikoljii is what was formerly known as "astronotus sp. rio orinoco/puerto carreno".