Clarifying the taxonomy of some cryptic blennies (Blenniidae) in their native and introduced range

Abstract

Omobranchus punctatus is native to the Indo-Pacific region and invasive in the Atlantic region, currently being considered one of the most widely distributed blenny species. However, recent molecular studies indicated that O. punctatus is a complex of species, with three divergent mtDNA lineages identified to date, stressing the need for a taxonomic revision. In this study, we used an integrative approach, combining morphological and genetic data, to shed light on the taxonomy and distribution of O. punctatus. Moreover, we provide the first genetic records of introduced populations in Brazil and discuss the introduction pattern of this species in this region. Morphological data shows that O. punctatus consists of at least five distinct and geographically restricted species: O. punctatus sensu stricto, O. dispar, O. sewalli, O. cf. kochi, and O. cf. japonicus. Species delimitation analyses performed using the mtDNA data available confirmed that O. punctatus sensu stricto, O. dispar and O. sewalli correspond to different species that started to diverge about 2.6 Mya. Furthermore, O. sewalli was identified as the invasive species colonizing Atlantic shores. The existence of historical oceanographic barriers, such as the emergence of the Sunda Shelf in the Eastern Indian Ocean during the Pleistocene, and the biological traits of these blennies are the most likely factors responsible for their genetic differentiation and subsequent speciation.

Similar Ones Are Not Related and Vice Versa—New Dendronotus Taxa (Nudibranchia: Dendronotidae) from the North Atlantic Ocean Provide a Platform for Discussion of Global Marine Biodiversity Patterns

“…Our study, therefore, reveals the complex combinations of morphological and molecular similarities and differences (Figures 1-6), which contradict the simplistic division into 'cryptic' or 'non-cryptic' species groups, which only superficially appear indistinguishable until detailed integration of niche, molecular data, or other lines of evidence reveal clearly different and distinguishable species lineages [79]. This contrast led to a misleading distinction between 'cryptic', 'pseudocryptic' and just 'ordinary' species [80][81][82][83][84][85][86][87]; see detailed discussion in [16,18,63,88,89]. This consideration is of crucial importance for practical taxonomy.…”

Trypauchen vagina (Bloch & Schneider, 1801) a new established species in the Southwestern Atlantic

“…This is not the first example of a non‐indigenous species reported from areas close to Port of Santos and Paranaguá. Other fish species like Butis koilomatodon (Bleeker 1849) (Contente et al., 2016; Macieira et al., 2012), Opsanus beta (Goode & Bean, 1880) (Carvalho et al., 2022) and Omobranchus sewalli (Fowler, 1931) (Cabezas et al., 2022) were also reported from areas near those ports. The Brazilian navy claim that every ship must replace the ballast water in high seas (Costa et al., 2016), however non‐indigenous fish species are being reported continuously.…”