What is the fine-grained topic of the following text: Systematic remarks (with taxonomic history): well defined (taxonomic history : since description in 1912, a fish whose atypical morphology and variability have been strongly studied ; the systematic status then varies from subspecies to full species, until molecular biology evidence, showing that the morphological differenciation between populations is not found in mitochondrial genes). Only return the topic.
The systematic status and taxonomic history of a fish since its description in 1912.