First timetree of Sphyraenidae (Percomorpha) reveals a Middle Eocene crown age and an Oligo–Miocene radiation of barracudas

Abstract

The 27 extant species of the family Sphyraenidae represent one of the major groups of piscivorous teleost fishes in tropical and subtropical marine waters. In spite of their ecological importance, currently, no phylogenetic hypothesis is available for this group, and we do not know the tempo of evolution of this clade. In this study, we used a supermatrix approach to assemble a dataset of three mitochondrial loci for 20 sphyraenid species, and time-calibrated this new phylogeny. Our study supports the existence of three main groups of barracudas, which we labelled the "S. barracuda" group, the "S. obtusata" group and the "S. sphyraena" group. The timetree indicates a Late Paleocene age (~57 Ma) for the origin of the groups, and a Middle Eocene (~45 Ma) timing for the beginning of the radiation of extant lineages. Most extant species appear to belong to phylogenetic lineages dating to the Miocene (~5 to 23 Ma). Our study reveals multiple shifts between coral reef-associated and non-reef (usually more pelagic) habitats, as well as two independent origins of large body size within this group.

Chromosomal evolution in large pelagic oceanic apex predators, the barracudas (Sphyraenidae, Percomorpha)

“…The divergence between these species dates from more than 10 mya (Myocene). On the other hand, the "Sphyraena sphyraena" clade, which includes S. picudilla, has an ancient divergence in comparison with the "Sphyraena barracuda" clade, dating from 45 mya (Santini et al, 2014). Based on these data, the karyotypic patterns of the Sphyraena species here analyzed have shown to be discrepant with their phylogenetic relationships (Figure 2).…”

“…By contrast, population groups dependent on particular ecological regions and low vagility may be more susceptible to population stratification and fixation of particular karyotypic patterns (Molina and Galetti, 2004;Molina, 2007). With a complex evolutionary scenario, barracudas had their diversification period in the Oligocene, and since then, have undergone several ecological changes, with alternated preferences for reef and non-reef environments (Santini et al, 2014). Curiously, both S. guachancho and S. tome, occupying pelagic-neritic habitats (Figueiredo et al, 2002;Santini et al, 2014), and S. picudilla and S. barracuda, which occupy reef habitats, exhibit similar karyotypes.…”

“…In fact, a global phylogeographic survey in S. barracuda indicated a high gene flow over long distances in the Indo-Pacific, with genetic divergences in the Western and Eastern Atlantic populations (Daly Engel et al, 2012). Thus, the migratory behavior, besides the extensive period of evolutionary divergence among Sphyraenidae clades and the different historical contexts (multiple transitions between reef and non-reef habitats) that these lineages were submitted (Santini et al, 2014) seem to have mediated their chromosomal evolution. In fact, in addition to the shared features (2n, C-positive heterochromatin distribution, syntenic organization of 18S and 5S rDNA clusters and the large number of acrocentric elements), some few chromosome pairs exhibit divergences derived from pericentric inversions.…”

“…Chromosome types were classified by their arm ratio, as metacentric (m), submetacentric (sm), subtelocentric (st), and acrocentric (a) (Levan et al, 1964). Chromosomal data were analyzed in a phylogenetic context, based on recent molecular phylogeny proposed for Sphyraenidae species (Santini et al, 2014). Although the phylogenetic relationships available do not include S. tome, the only other species with a karyotypic description for comparison purposes was tentatively positioned close to S. picudilla, given that some of its morphological characters, such as the presence of a pectoral fin that extends past the origin of the pelvic fin, are shared with the latter species (Cervigón et al, 1992;Matsuura and Suzuki, 1997;Smith-Vaniz et al, 1999;Lessa and Nóbrega, 2000).…”

“…Although little is known about the various evolutionary aspects of Sphyraenidae, it is estimated that they have originated about 57 mya (Late Paleocene), with the most current lineages belonging to groups that emerged between 23.5-5.3 mya (Miocene) (Santini et al, 2014).…”