A new time-scale for ray-finned fish evolution

Abstract

The Actinopterygii (ray-finned fishes) is the largest and most diverse vertebrate group, but little is agreed about the timing of its early evolution. Estimates using mitochondrial genomic data suggest that the major actinopterygian clades are much older than divergence dates implied by fossils. Here, the timing of the evolutionary origins of these clades is reinvestigated using morphological, and nuclear and mitochondrial genetic data. Results indicate that existing fossil-based estimates of the age of the crown-group Neopterygii, including the teleosts, Lepisosteus (gar) and Amia (bowfin), are at least 40 Myr too young. We present new palaeontological evidence that the neopterygian crown radiation is a Palaeozoic event, and demonstrate that conflicts between molecular and morphological data for the age of the Neopterygii result, in part, from missing fossil data. Although our molecular data also provide an older age estimate for the teleost crown, this range extension remains unsupported by the fossil evidence. Nuclear data from all relevant clades are used to demonstrate that the actinopterygian whole-genome duplication event is teleost-specific. While the date estimate of this event overlaps the probable range of the teleost stem group, a correlation between the genome duplication and the large-scale pattern of actinopterygian phylogeny remains elusive.

Replacing the first-generation dentition in pufferfish with a unique beak

“…demonstrate that the firstgeneration set of marginal teeth is induced in a spatiotemporal series that represents the typical teleost and likely a general osteichthyan pattern (Fig. 3 A-C), the latter being conserved since the actinopterygian/sarcopterygian split at least 416 Mya (36). Thus, the pufferfish beak is not developed de novo, but rather emerges ontogenetically as a modification of the program for tooth replacement.…”

Molecular analysis of neurogenic placode development in a basal ray‐finned fish

“…Tetrapods (amphibians and amniotes) and teleosts are members, respectively, of the two sister groups of bony fish: sarcopterygians (lobe-finned fish) and actinopterygians (ray-finned fish). teleosts are by far the most speciose actinopterygian group, there are also four extant non-teleost actinopterygian taxa: polypterids (bichirs), which are accepted as the most basal actinopterygian group (see, e.g., Hurley et al, 2007), chondrosteans (sturgeons and paddlefish), lepisosteids (gars), and amiids (bowfin). The precise phylogenetic relationship of chondrosteans, lepisosteids, amiids, and teleosts is still debated (see Hurley et al, 2007;Inoue et al, 2003;Venkatesh et al, 2001).…”

“…teleosts are by far the most speciose actinopterygian group, there are also four extant non-teleost actinopterygian taxa: polypterids (bichirs), which are accepted as the most basal actinopterygian group (see, e.g., Hurley et al, 2007), chondrosteans (sturgeons and paddlefish), lepisosteids (gars), and amiids (bowfin). The precise phylogenetic relationship of chondrosteans, lepisosteids, amiids, and teleosts is still debated (see Hurley et al, 2007;Inoue et al, 2003;Venkatesh et al, 2001). Cladistic analysis of morphological data from extant and fossil taxa, as well as Bayesian and maximum likelihood analysis of nuclear molecular data, provide strong statistical support for chondrosteans (sturgeons and paddlefish) as the sister group to a monophyletic neopterygian clade comprising lepisosteans, amiids, and teleosts (Hurley et al, 2007).…”

Resolution of ray-finned fish phylogeny and timing of diversification

“…Actinopterygii contains more than 30,000 species (2), with all but 50 being teleosts (3). Compared with other large vertebrate radiations, such as mammals (4) or birds (5), a general consensus on the phylogenetic relationships and timing of diversification among the major actinopterygian and teleost lineages is lacking (3,6,7). This uncertainty about relationships has prevented the development of a comprehensive time-calibrated phylogeny of ray-finned fishes, which is necessary to understand macroevolutionary processes that underlie their diversity.…”

“…JX190073-JX191369). the most recent common ancestor of living teleosts range from 310 to 350 Ma based on whole mtDNA genome sequences (28), ∼320 Ma based on comparisons of paralogous gene copies resulting from the teleost whole-genome duplication (WGD) event (29), and 173-260 Ma based on fossil-calibrated nuclear gene phylogenies (7,19,20). Although these studies estimated ages for the crown teleost clade that are older than the fossil record, molecular age estimates across ray-finned fish lineages include those that are older, as well as younger, than fossil-based estimates.…”