Time-calibrated phylogeny of neotropical freshwater fishes.

Neotropical Freshwater Fish (NFF) fauna exhibits the greatest phenotypic disparity and species richness among all continental aquatic vertebrate faunas, with more than 6,345 species distributed across the mostly tropical regions of Central and South America. The last two decades have seen a proliferation of molecular phylogenies, often at the species level, covering almost all 875 valid NFF genera. This study presents the most comprehensive genome-wide, time-calibrated phylogenetic hypothesis of NFF species to date, based on DNA sequences generated over decades through the collaborative efforts of the multinational ichthyological research community.

Landscape dynamics and diversification of the megadiverse South American freshwater fish fauna.

Landscape dynamics are widely thought to govern the tempo and mode of continental radiations, yet the effects of river network rearrangements on dispersal and lineage diversification remain poorly understood. We integrated an unprecedented occurrence dataset of 4,967 species with a newly compiled, time-calibrated phylogeny of South American freshwater fishes-the most species-rich continental vertebrate fauna on Earth-to track the evolutionary processes associated with hydrogeographic events over 100 Ma. Net lineage diversification was heterogeneous through time, across space, and among clades.

Squalomix: shark and ray genome analysis consortium and its data sharing platform.

The taxon Elasmobranchii (sharks and rays) contains one of the long-established evolutionary lineages of vertebrates with a tantalizing collection of species occupying critical aquatic habitats. To overcome the current limitation in molecular resources, we launched the Squalomix Consortium in 2020 to promote a genome-wide array of molecular approaches, specifically targeting shark and ray species. Among the various bottlenecks in working with elasmobranchs are their elusiveness and low fecundity as well as the large and highly repetitive genomes.

The whale shark genome reveals patterns of vertebrate gene family evolution.

Chondrichthyes (cartilaginous fishes) are fundamental for understanding vertebrate evolution, yet their genomes are understudied. We report long-read sequencing of the whale shark genome to generate the best gapless chondrichthyan genome assembly yet with higher contig contiguity than all other cartilaginous fish genomes, and studied vertebrate genomic evolution of ancestral gene families, immunity, and gigantism. We found a major increase in gene families at the origin of gnathostomes (jawed vertebrates) independent of their genome duplication.

Chromosome-Level Genome Assembly of Chinese Sucker (Myxocyprinus asiaticus) Reveals Strongly Conserved Synteny Following a Catostomid-Specific Whole-Genome Duplication.

Fishes of the family Catostomidae ("suckers"; Teleostei: Cypriniformes) are hypothesized to have undergone an allopolyploidy event approximately 60 Ma. However, genomic evidence has previously been unavailable to assess this hypothesis. We sequenced and assembled the first chromosome-level catostomid genome, Chinese sucker (Myxocyprinus asiaticus), and present clear evidence of a catostomid-specific whole-genome duplication (WGD) event ("Cat-4R").

Adaptive shifts underlie the divergence in wing morphology in bombycoid moths.

The evolution of flapping flight is linked to the prolific success of insects. Across Insecta, wing morphology diversified, strongly impacting aerodynamic performance. In the presence of ecological opportunity, discrete adaptive shifts and early bursts are two processes hypothesized to give rise to exceptional morphological diversification.

Retroviral integrations contribute to elevated host cancer rates during germline invasion.

Repeated retroviral infections of vertebrate germlines have made endogenous retroviruses ubiquitous features of mammalian genomes. However, millions of years of evolution obscure many of the immediate repercussions of retroviral endogenisation on host health. Here we examine retroviral endogenisation during its earliest stages in the koala (Phascolarctos cinereus), a species undergoing germline invasion by koala retrovirus (KoRV) and affected by high cancer prevalence.

Structure, gene order, and nucleotide composition of mitochondrial genomes in parasitic lice from Amblycera.

Parasitic lice have unique mitochondrial (mt) genomes characterized by rearranged gene orders, variable genome structures, and less AT content compared to most other insects. However, relatively little is known about the mt genomes of Amblycera, the suborder sister to all other parasitic lice. Comparing among nine different genera (including representative of all seven families), we show that Amblycera have variable and highly rearranged mt genomes.

Head Shape Modulates Diversification of a Classic Cichlid Pharyngeal Jaw Innovation.

Functional innovations are often invoked to explain the uneven distribution of ecological diversity. Innovations may provide access to new adaptive zones by expanding available ecological opportunities and may serve as catalysts of adaptive radiation. However, diversity is often unevenly distributed within clades that share a key innovation, highlighting the possibility that the impact of the innovation is mediated by other traits.

Phylogenetic classification of extant genera of fishes of the order Cypriniformes (Teleostei: Ostariophysi).

The order Cypriniformes is the most diverse order of freshwater fishes. Recent phylogenetic studies have approached a consensus on the phylogenetic relationships of Cypriniformes and proposed a new phylogenetic classification of family-level groupings in Cypriniformes. The lack of a reference for the placement of genera amongst families has hampered the adoption of this phylogenetic classification more widely.

Island- and lake-like parallel adaptive radiations replicated in rivers.

Parallel adaptive radiations have arisen following the colonization of islands by lizards and lakes by fishes. In these classic examples, parallel adaptive radiation is a response to the ecological opportunities afforded by the colonization of novel ecosystems and similar adaptive landscapes that favour the evolution of similar suites of ecomorphs, despite independent evolutionary histories. Here, we demonstrate that parallel adaptive radiations of cichlid fishes arose in South American rivers.

Ecological opportunity alters the timing and shape of adaptive radiation.

The uneven distribution of diversity is a conspicuous phenomenon across the tree of life. Ecological opportunity is a prominent catalyst of adaptive radiation and therefore may alter patterns of diversification. We evaluated the distribution of shifts in diversification rates across the cichlid phylogeny and the distribution of major clades across phylogenetic space.

Draft sequencing and assembly of the genome of the world's largest fish, the whale shark: Rhincodon typus Smith 1828.

Background: The whale shark (Rhincodon typus) has by far the largest body size of any elasmobranch (shark or ray) species. Therefore, it is also the largest extant species of the paraphyletic assemblage commonly referred to as fishes. As both a phenotypic extreme and a member of the group Chondrichthyes - the sister group to the remaining gnathostomes, which includes all tetrapods and therefore also humans - its genome is of substantial comparative interest.

Resolving Cypriniformes relationships using an anchored enrichment approach.

Background: Cypriniformes (minnows, carps, loaches, and suckers) is the largest group of freshwater fishes in the world (~4300 described species). Despite much attention, previous attempts to elucidate relationships using molecular and morphological characters have been incongruent. In this study we present the first phylogenomic analysis using anchored hybrid enrichment for 172 taxa to represent the order (plus three out-group taxa), which is the largest dataset for the order to date (219 loci, 315,288 bp, average locus length of 1011 bp).

Two new species of spotted Hypancistrus from the Rio Negro drainage (Loricariidae, Hypostominae).

Two new species, Hypancistrus phantasma and Hypancistrus margaritatus, are described based on material from the Rio Negro drainage. Both species are distinguished from congeners by unique color patterns. Hypancistrus phantasma is described from the Rio Uaupes and differs from congeners by having a tan body with small dark spots (vs.

Three new species of saddled loricariid catfishes, and a review of Hemiancistrus, Peckoltia, and allied genera (Siluriformes).

Three new species of saddled hypostomine loricariids are described. According to a recent phylogenetic analysis, these species are members of the genus Peckoltia. The species differ from all described Peckoltia except Peckoltiafurcata and Peckoltiasabaji by having the dentaries meet at an angle greater than 90°.