The triggerfishes (family Balistidae) and filefishes (family Monacanthidae) comprise a charismatic superfamily (Balistoidea) within the diverse order Tetraodontiformes. This group of largely marine fishes occupies an impressive ecological range across the world's oceans, and is well known for its locomotor and feeding diversity, unusual body shapes, small genome size, and ecological and economic importance. In order to investigate the evolutionary history of these important fish families, we used multiple phylogenetic methods to analyze molecular data from 86 species spanning the extant biodiversity of Balistidae and Monacanthidae. In addition to three gene regions that have been used extensively in phylogenetic analyses, we include sequence data for two mitochondrial regions, two nuclear markers, and the growth factor gene bmp4, which is involved with cranial development. Phylogenetic analyses strongly support the monophyly of the superfamily Balistoidea, the sister-family relationship of Balistidae and Monacanthidae, as well as three triggerfish and four filefish clades that are well resolved. A new classification for the Balistidae is proposed based on phylogenetic groups. Bayesian topology, as well as the timing of major cladogenesis events, is largely congruent with previous hypotheses of balistid phylogeny. However, we present a novel topology for major clades in the filefish family that illustrate the genera Aluterus and Stephanolepis are more closely related than previously posited. Molecular rates suggest a Miocene and Oligocene origin for the families Balistidae and Monacanthidae, respectively, and significant divergence of species in both families within the past 5 million years. A second key finding of this study is that, relative to the other protein-coding gene regions in our DNA supermatrix, bmp4 shows a rapid accumulation of both synonymous and non-synonymous substitutions, especially within the family Monacanthidae. Overall substitution patterns in bmp4 support the hypothesis of stabilizing selection during the evolutionary history of regulatory genes, with a small number of isolated examples of accelerated non-synonymous changes detected in our phylogeny.

The damselfishes (family Pomacentridae) inhabit near-shore communities in tropical and temperature oceans as one of the major lineages in coral reef fish assemblages. Our understanding of their evolutionary ecology, morphology and function has often been advanced by increasingly detailed and accurate molecular phylogenies. Here we present the next stage of multi-locus, molecular phylogenetics for the group based on analysis of 12 nuclear and mitochondrial gene sequences from 345 of the 422 damselfishes. The resulting well-resolved phylogeny helps to address several important questions about higher-level damselfish relationships, their evolutionary history and patterns of divergence. A time-calibrated phylogenetic tree yields a root age for the family of 55.5 mya, refines the age of origin for a number of diverse genera, and shows that ecological changes during the Eocene-Oligocene transition provided opportunities for damselfish diversification. We explored the idea that body size extremes have evolved repeatedly among the Pomacentridae, and demonstrate that large and small body sizes have evolved independently at least 40 times and with asymmetric rates of transition among size classes. We tested the hypothesis that transitions among dietary ecotypes (benthic herbivory, pelagic planktivory and intermediate omnivory) are asymmetric, with higher transition rates from intermediate omnivory to either planktivory or herbivory. Using multistate hidden-state speciation and extinction models, we found that both body size and dietary ecotype are significantly associated with patterns of diversification across the damselfishes, and that the highest rates of net diversification are associated with medium body size and pelagic planktivory. We also conclude that the pattern of evolutionary diversification in feeding ecology, with frequent and asymmetrical transitions between feeding ecotypes, is largely restricted to the subfamily Pomacentrinae in the Indo-West Pacific. Trait diversification patterns for damselfishes across a fully resolved phylogeny challenge many recent general conclusions about the evolution of reef fishes.

In less than a decade, the Indo-Pacific red lionfish, Pterois volitans, has rapidly spread throughout the Western North Atlantic (Whitfield et al. 2007). To improve understanding of the lionfish invasion, there is a pressing need for comparative knowledge on lionfishes from their native ranges.During a 2008 rapid assessment of reef fish diversity among the Southwest Islands of the Palau Archipelago, lionfishes were collected while SCUBA diving using spears and by dispersing 4 kg of the ichthyotoxin rotenone at positions along the reef. Collection depths ranged from 2 to 36 m, and seawater temperatures varied from 26-28.2 o C. A total of 15 lionfish specimens were collected from the fringing reefs of Sonsorol, Fana, and Tobi islands and the Helen Reef Atoll (Lat 2 o 52¢N, Long 131 o 46¢ E). Four species of lionfishes were identified (Fig. 1).Lionfishes were present in 28.9% of the sites accounting for only a small portion of the overall reef fish biodiversity. Unlike the high abundances of P. volitans in the Western Atlantic (i.e.,~21.2-390 individuals ha -1 ) (Whitfield et al. 2007; Green and Cote 2009), conservative estimates from Helen Reef Atoll (N = 28 sites; average rotenone collection area~13 m 2 ) were relatively low for all four species (i.e. Pterois antennata~4.4 ind ha -1 , Pterois radiata~13.1 ind ha -1 , and~2.2 ind ha -1 for Dendrochirus biocellatus and P. volitans).In contrast to the Western Atlantic, lionfish were not observed roaming in the open. They were collected hiding in the reef matrix (Fig. 2a). The lower abundances and cryptic behavior may be related to high reef fish diversity limiting resources and increasing mortality. Groupers (Serranidae) have been indicated as potential predators as well as competitors of lionfishes (Maljkovic and Van Leeuwen 2008). This expedition encountered robust grouper populations identifying over 20 species from 7 genera ( Fig. 2b-d).Since lionfishes remain popular in the aquarium trade, there is still the threat of future introductions of new Pterois species into the Atlantic. These data provide a snapshot of lionfish biodiversity from a remote and still pristine coral reef ecosystem in the Western Pacific.

The damselfishes (family Pomacentridae) inhabit near-shore communities in tropical and temperature oceans as one of the major lineages with ecological and economic importance for coral reef fish assemblages. Our understanding of their evolutionary ecology, morphology and function has often been advanced by increasingly detailed and accurate molecular phylogenies. Here we present the next stage of multi-locus, molecular phylogenetics for the group based on analysis of 12 nuclear and mitochondrial gene sequences from 330 of the 422 damselfish species. The resulting well-resolved phylogeny helps to address several important questions about higher-level damselfish relationships and the monophyly of genera, including Chromis, Chrysiptera, Parma and Stegastes. A time-calibrated phylogenetic tree scaled using fossil data and recent estimated ovalentarian clade ages, yields an older root age for the family (55.3 mya) than previously proposed, refines the age of origin for a number of diverse genera, and shows that ecological changes during the Eocene-Oligocene transition provided opportunities for damselfish diversification. We explored the idea that body size extremes have evolved repeatedly among the Pomacentridae, and demonstrate that large and small body sizes have evolved independently at least 30 times and with asymmetric rates of transition. We tested the hypothesis that transitions among three dietary ecotypes (benthic herbivory, pelagic planktivory and intermediate omnivory) are asymmetric, with higher transition rates from intermediate omnivory to either planktivory or herbivory. Using multistate hidden-state speciation and extinction models, we found that dietary ecotype is significantly associated with patterns of diversification across the damselfishes, and that the highest rates of net diversification are associated with pelagic planktivory. We also conclude that the pattern of evolutionary diversification in feeding ecology, with frequent and asymmetrical transitions between a small number of feeding ecotypes, is largely restricted to the subfamily Pomacentrinae in the Indo-West Pacific.