Molecular diversity and historical phylogeography of the widespread genus Mastiglanis (Siluriformes: Heptapteridae) based on palaeogeographical events in South America

Abstract

The catfish family Heptapteridae, endemic in the Neotropical region, is composed of small- to medium-sized species. The genus Mastiglanis was monotypic until very recently and is often misidentified as Imparfinis because of similarities in diagnostic characters, including the length of maxillary barbels and limited pigmentation. We provide the first molecular inference of diversity for samples identified as Mastiglanis. Partial 16S and COI sequences were produced for 84 samples identified morphologically as Mastiglanis from the Amazon, Orinoco and Essequibo river basins. Species delimitation and phylogenetic methods recovered the genus as monophyletic, but samples assigned to the species Mastiglanis asopos yielded 21 distinct operational taxonomic units, often in sympatry. The first cladogenesis event, at ~12 Mya, was associated with marine incursions and/or vicariance events between the northward-flowing systems in the west and the rivers that drain to the east. Subsequent diversification during the Miocene and Pliocene was inferred to have resulted from environmental changes associated with Andean orogeny, whereas recent diversification in the late Pliocene and Pleistocene was inferred to result from environmental changes during glacial cycles. Despite the many probable cryptic species found across the large geographical distribution of the genus, further sampling is expected to increase taxonomic richness in this genus.

The role of Miocene-Pleistocene environmental change in diversification of the genusHypoclinemusChabanaud, 1928

“…The formation of the Pebas mega-wetlands, stretching from the Caribbean to southern South America [11, 14], played a significant role in driving the speciation of neotropical fish species [18]. This extensive swampy system covered the western Amazon during most of the Miocene (around 10 to 20 mya) [15] and experienced marine incursions from the Caribbean, which likely influenced the adaptations of species from estuarine to freshwater conditions The Pebas mega-wetlands This supports the hypothesis that the colonization of inland waters originated from the north and the Caribbean Sea, resulting in the mixed sister clade position of Apionichthys relative to Hypoclinemus in our biogeographic reconstruction (Fig.…”

“…The highlands acted as a refugee during glaciation period followed by colonization of lowlands, along with all actors relating here (e.g: marine incursions, uplift of paleoarches, historical connections promoting cross-drainage dispersal). All this evidence suggests a significant role of Pleistocene as a force that promotes speciation in neotropical fish species [4,18,58,66,69,70), where Hypoclinemus is the more recent case.…”

“…Subsequently, the diversification of taxa of marine origin depends on speciation processes common to continental freshwaters. In the case of the Amazon, periods of glaciation during the Pleistocene and tectonic processes associated with the uplift of the Andes resulted in changes in abiotic conditions and drainage connections in the region [4,16,17,18]. However, for other families that have both marine and freshwater species (e.g., Achiridae), there is little information about the influence of these past processes of speciation [19].…”

“…Given the complex topology of Greater Amazonia (sensu Van der Sleen and Albert, [31]), Hypoclinemus is also a good candidate to investigate how speciation processes may affect the evolutionary history of Neotropical fish species, which in many cases include the divergence of cryptic lineages [18, 35, 36, 37]. In freshwater environments, fishes found in smaller streams and headwaters tend to be more strongly fragmented and isolated, even on small spatial scales, providing ample opportunity for speciation [18, 38], while fishes common to major rivers with accumulated sedimentary substrates tend to speciate based on large-scale vicariance events between basins and ecological differences across basins [32]. The geographic range of H. mentalis spans major basins (Amazon, Orinoco, Essequibo) that present spatial and environmental heterogeneity, factors that can influence speciation [39].…”

Molecular identification of whole squids and calamari at fairs and markets in regions of Latin America

“…Molecular methods have been widely used, firstly, to identify new species or populations of different species, thus providing a complement to pure systematic studies, with their applicability in the identification of species already consolidated in several different taxonomic groups (Virgilio et al 2010; Hollingsworth et al 2011, Gales et al 2022; Rodrigues-Filho et al 2023), especially DNA barcode methods (Hebert et al 2003). This technique is based on analyzing the variability of a short nucleotide sequence to assess differences between species (Hebert et al 2003).…”