Sympatric morphotypes of the restricted-range Tashan Cave Garra: distinct species or a case of phenotypic plasticity?

• Published in: Environmental biology of fishes Vol. 105; no. 9; pp. 1251 - 1260
• Main Authors: Hashemzadeh Segherloo, Iraj, Najafi Chaloshtory, Sajad, Naser, Murtada D., Yasser, Amaal Gh, Tabatabaei, Seyedeh Narjes, Piette-Lauziere, Gabriel, Mashtizadeh, Amirhossein, Elmi, Amirmohammad, Sedighi, Omid, Changizi, Alieh, Hallerman, Eric, Bernatchez, Louis
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.09.2022; Springer Nature B.V
• Subjects: Algorithms; Animal Systematics/Taxonomy/Biogeography; Biomedical and Life Sciences; Character displacement; cytochrome-c oxidase; Cytochromes; DNA; DNA sequences; Ecological distribution; Ecological niches; Environment; Freshwater & Marine Ecology; Garra; Gene sequencing; Genetic distance; habitats; Iran; Life Sciences; Mitochondria; Mitochondrial DNA; morphs; mouth; Nature Conservation; Niches; Nucleotide sequence; nucleotide sequences; Phenotypic plasticity; Phylogenetics; Phylogeny; Population genetics; Population studies; Species; Sympatric populations; sympatry; Taxonomy; Zoology; Iran; Taxonomic feature; Character release; Tashan Cave; Character displacement
• ISSN: 0378-1909; 1573-5133
• DOI: 10.1007/s10641-022-01329-2

Among Tashan cave barb Garra tashanensis inhabiting a small cave in southwest Iran, two mental disc (sucking mouth disc) forms were observed. To assess their phylogenetic relationships, disc-less and disc-bearing individuals were analyzed using mitochondrial cytochrome oxidase subunit I ( COI ) partial DNA sequences. Both mental disc forms nested within one clade with absolute bootstrap support ( BS  = 100), and the genetic distances between the disc-bearing and disc-less individuals (0.3–0.8%) were considerably lower than inter-species mtDNA sequence distances reported among members of the genus Garra ; further, most species delimitation algorithms used here showed disc-bearing and disc-less Tashan cave barbs to be members of a single taxonomic unit. Hence, the observed mental disc variation was not inferred to be a taxonomic feature or a consequence of character displacement. Instead, it was inferred to be a case of character release to diversify among ecological niches in the limited subterranean habitat or a case of relaxed selection, which should be clarified in detail in follow-up ecological and population genetic studies.