DOI: 10.1111/jbi.70318 ISSN: 0305-0270
Clarifying the
Labrisomus
Conundrum: Deep Divergence, Cryptic Lineages, and a Genetic Melting Pot in the Atlantic Ocean (Teleostei, Labrisomidae)
Gabriel Soares Araujo, João Luiz Gasparini, Luiz A. Rocha, Hudson T. Pinheiro, Marcelo V. Kitahara, Anderson V. Vilasboa, Carol A. Stepien, Sergio R. Floeter, Fabio Di Dario ABSTRACT
Aim
We evaluate the phylogenetic relationships and taxonomic validity of Atlantic species of
Labrisomus
, identifying the lineages currently assigned to
L. nuchipinnis
, and assessing the role of biogeographic barriers in shaping the evolutionary history and geographic distribution of the genus.
Methods
We assembled an extensive mitochondrial and nuclear DNA dataset of Atlantic species of
Labrisomus
to perform multi‐locus phylogenetic divergence‐time and historical biogeographic analyses, reconstruct haplotype networks, estimate genetic distances, implement lineage delimitation tests and estimate migration rates.
Results
Labrisomus nuchipinnis
is a species complex comprising three deeply divergent lineages: one broadly distributed in the western Atlantic, another restricted to Florida (USA), and a third mostly distributed in the eastern Atlantic. A new usage of
L. nuchipinnis
is proposed, with the species restricted to the western Atlantic, and with the revalidation of
Clinus canariensis
(as
L. canariensis
) for the mostly eastern Atlantic lineage. Despite their anatomical similarity,
L. nuchipinnis
and its Atlantic congeners diverge significantly genetically. Unusual genetic connectivity between samples of
L. canariensis
from the eastern Atlantic and southern Brazil suggests a potential trans‐Atlantic genetic pathway.
Main Conclusion
The deep genetic divergence among lineages previously included in the
L. nuchipinnis
complex contrasts with their anatomical similarity, making
Labrisomus
one of the most challenging cases of cryptic diversification among reef fishes. The evolutionary history of the genus likely involved spatial segregation driven by ecological niche overlap. Ecological factors may influence distribution patterns among species of the genus more strongly than geographic distance. The apparently isolated population of
L. canariensis
off southern Brazil provides a well‐documented case of disjunct distribution of a reef fish species between the eastern Atlantic and south Brazil, highlighting the potential of this region as a melting‐pot of biodiversity.