DNA barcoding and species delimitation for dogfish sharks belonging to the Squalus genus (Squaliformes: Squalidae).

ARIZA, A. A.; ADACHI A. M. C. L; ROQUE, P.; HAZIN, F. H.; VIANNA, M.; ROTUNDO, M.; DELPIANI, S. M.; DIAZ DE ASTARLOA, JUAN M; DELPIANI, G. E.; OLIVEIRA, C.; FORESTI, F.; CRUZ, VANESSA P.

Diversity

MDPI

Año: 2022 vol. 14 p. 1 - 13

The Squalus genus comprises a group of small demersal sharks occurring circumglobally,popularly known as dogfish sharks. This genus exhibits a conserved morphology, thus makingcorrect morphological identification difficult. Considering these taxonomic problems and the scarcityof molecular data, the present study aimed to identify Squalus genus MOTUs, using DNA barcodingfor species delimitation via ABGD (automatic barcode gap discovery), PTP (Poisson tree process),and GMYC (general mixed Yule coalescent) employing the mitochondrial COI gene. A total of69 sequences were generated from samples obtained from the American coast in both the Atlantic andPacific Oceans. The ABGD analysis was the most conservative among the three applied delimitations,indicating three taxonomic units, while the PTP analysis revealed nine MOTUs, with two conflictingunits noted between S. clarkae + S. mitsukurii and S. albicaudus + S. cubensis. The GMYC analysisindicated an excessive division, with S. acanthias and S. mitsukurii subdivided into six MOTUs eachand S. blainville, into four. These findings demonstrated that Squalus presents a complex of previouslydefined species, with misidentified samples deposited in databases leading to difficulties in analyzingthe real distribution and diversity of species belonging to this genus. Thus, further efforts to highlightpossible new species are recommended.