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Split networks of the morphological tree with the species tree. Splits that agreed between the two trees are indicated by strictly bifurcating splits. Conflicting splits are represented as a network of edges. (A) Split network for all taxa. (B) Split network after the removal A. medusa. (C) Split network after the removal of A. medusa and A. spinosa.
Source publication
Neotropical reef fish communities are species-poor compared to those of the Indo-West Pacific. An exception to that pattern is the blenny clade Chaenopsidae, one of only three rocky and coral reef fish families largely endemic to the Neotropics. Within the chaenopsids, the genus Acanthemblemaria is the most species-rich and is characterized by elab...
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Context 1
... splits network of the morphological tree with the sequencebased tree revealed many areas of agreement between the two trees, as indicated by strictly bifurcating splits, including the entire ''hancocki species group'' clade ( Fig. 2A). The two taxa that were responsible for the majority of the conflict between the two trees, as visualized by conflicting networks of splits, were A. spinosa and A. medusa. For both of these taxa a relatively large number of extra splits had to be traversed to unite them with clades specified by either the morphological or molecular ...
Context 2
... by conflicting networks of splits, were A. spinosa and A. medusa. For both of these taxa a relatively large number of extra splits had to be traversed to unite them with clades specified by either the morphological or molecular phylogeny. When both of these taxa were removed from the tree, conflicting splits disappeared from the splits networks (Fig. ...
Context 3
... species were responsible for most of the conflict between the molecular and morphological phylogenies -A. medusa and A. spinosa (Fig. 2). A. spinosa (the ''spinyhead blenny'') has an elaborate suite of spinous processes on several bones of the head. A. maria has the most elaborate spinous processes in the group (Böhlke, 1961) and a gross skull morphology similar to A. spinosa (Smith-Vaniz and Palacio, 1974). Analyses based on morphological data recovered A. maria as the ...
Citations
... Within this group, there is an emergent pattern of reduced connectivity between populations, defined by large and contrasting levels of mitochondrial and nuclear sequence divergence. Distinct population structuring has been found over extremely short spatial scales using mitochondrial markers (Lin et al. 2009;Eytan and Hellberg 2010), and species delimitation of cryptic species using mitochondrial COI has shown large levels of sequence divergence (Victor 2010; Eytan and Hellberg 2010;Eytan et al. 2012). Multiple species of chaenopsids have shown evidence of significant allopatric population structuring; within the Gulf of California (Bernardi et al. 2003;Lin et al. 2009;Lin and Galland 2010;Riginos 2005) and the Caribbean (Eytan and Hellberg 2010). ...
... Within other chaenopsid blennies there have been reports of large and contrasting levels of mitochondrial and nuclear sequence divergence (Lin et al. 2009;Eytan et al. 2012), and it is thought that postzygotic barriers (mitonuclear discordance and hybrid breakdown; Burton 1987Burton , 1990Willett and Burton 2004;Ellison et al. 2008;Oliveira et al. 2008;Willett 2012) may be enforcing species boundaries in some members of this species. Acanthemblemaria spinosa has an unusually high mitochondrial-to-nuclear substitution rate ratio (37:1; Eytan and Hellberg 2010) and one of the fastest COI substitution rates reported in vertebrates (11.22% per million years; Nabholz et al. 2008;Welch et al. 2008). ...
Life history characteristics of cryptobenthic reef fishes (CRFs), such as their fast growth and reproductive rates, near-shore larval retention and high turnover, predispose these species to rapid diversification and cryptic speciation. This may be particularly true for isolated CRF populations. The sailfin blenny, Emblemaria pandionis, is widespread throughout the Caribbean and is found on the reefs of the Flower Garden Banks, an isolated reef system in the NW Gulf of Mexico. Using DNA barcoding and multi-locus delimitation, we show that E. pandionis is a species complex comprised of at least four distinct taxonomic units in the Caribbean, one at the Flower Garden Banks, a second in eastern Florida, a third in the central Caribbean and a fourth in Curaçao. The phylogenetic relationships within the E. pandionis species complex are defined by well-established phylogeographic barriers to gene flow in the Caribbean. Populations of E. pandionis from eastern Florida are genetically distinct from populations found in the Bahamas, highlighting the role of the Florida Strait as a strong barrier to gene flow and populations in Curaçao are deeply divergent from all other populations sampled in the Caribbean. Results from this study highlight the roles of isolated reefs and ocean currents in the speciation of cryptobenthic reef fishes.
... The latter study noted minor meristic and body size differences between individuals from South America and Central America and attributed these to cooler water temperatures along the northern coast of South America. Subsequent collections from the coasts of Venezuela permitted further study of specimens from this area including comparison of molecular sequence data with specimens from Panama (Eytan et al. 2012). These additional data revealed distinctive genetic differences that warrant recognition of the South American form as a new species. ...
... observ.). Based on data from several genes, Eytan et al. (2012) estimated the divergence time of the two species as 0.97 million years (range = 0.38-1.71). ...
Acanthemblemaria aceroi new species is described from the upwelling region of the Caribbean coasts of Venezuela and Colombia. It differs from its closest relative, Acanthemblemaria rivasi Stephens, 1970, known from Panama and Costa Rica, in the posterior extent of the infraorbitals, details of head spination, and unique COI sequences. The description of Acanthemblemaria johnsonsi Almany & Baldwin, 1996, heretofore known only from Tobago, is expanded based on specimens from islands offshore of eastern Venezuela.
... All protein-coding genes (COI, cytochrome b, RAG-1, and TMO-4C4) were assigned codon positions under the minimizing stop codon algorithm and translated to amino acids in Mesquite 3.51 to ensure the absence of stop codons associated with pseudogenes. Fishes in the order Blenniiformes have been reported to have a high rate of molecular evolution, especially in protein-coding genes (Lin and Hastings 2011;Eytan et al. 2012). To address the problem regarding 3rd codon saturation, four protein-coding gene loci were tested for saturation using Xia's test in DAMBE7 (Xia and Kumar 2018). ...
Several temperate marine taxa of the northern hemisphere follow a trans-Pacific biogeographic track with representatives on either side of the intervening boreal waters. Shelter-dwelling blenniiform fishes of the genus Neoclinus exhibit this trans-Pacific distribution pattern with three species in the eastern North Pacific and eight species in the western North Pacific. We reconstructed the phylogeny of the Neocliniini (Neoclinus and the monotypic Mccoskerichthys) using six genetic markers: four mitochondrial genes (COI, cytochrome b, 12S and 16S), and two nuclear genes (RAG-1, TMO-4C4). Ancestral state reconstruction and molecular clock dating were used to explore hypothetical ancestral distributions and area relationships, and to estimate divergent times within this group. The monophyly of the genus Neoclinus, and the reciprocal monophyly of the eastern Pacific and western Pacific lineages were supported. Available evidence, including the eastern Pacific and western Atlantic occurrence of a New World clade of blennioid fishes that includes this lineage, supports the origin of the Neocliniini in the eastern Pacific with a single divergence event to the west across the North Pacific by the ancestor of the western Pacific clade. Estimated divergence time of the eastern and western Pacific clades of Neoclinus was 24.14 million year ago, which falls during the Oligocene epoch. Estimated times of divergence in other trans-Pacific lineages of marine fishes vary widely, from recent Pleistocene events to as early as 34 mya.
... Thus, dietary differentiation pertaining to both composition and richness of prey items may play an important part in the evolutionary history and coexistence of tripterygiid and chaenopsid lineages in the Caribbean. Morphological, behavioral, and physiological adaptations, which have been documented for the two Acanthemblemaria species (Clarke 1999;Clarke et al. 2009;Eytan et al. 2012), support this hypothesis and highlight the importance of considering multiple facets of organismal adaptations when disentangling the ecological niches of closely related species. ...
Ecological niches hold critical information concerning the eco-evolutionary dynamics that govern biodiversity and abundance patterns. Cryptobenthic reef fishes account for approximately half of all reef fish species and are an abundant and important group on coral reefs worldwide. Yet, due to their small size and inconspicuous lifestyles, relatively little is known about the ecological niches of most cryptobenthic species. Here, we use gut content DNA metabarcoding to determine dietary niche overlap and prey richness in four sympatric species of cryptobenthic reef fishes in two genera (Acanthemblemaria aspera, A. spinosa, Enneanectes altivelis, and E. matador). Furthermore, we test whether dietary differentiation corresponds with differences in species distribution patterns across twelve sites on the Mesoamerican Barrier Reef in Belize. Our approach reveals dietary partitioning among the four species, which is further supported by low edge density and high modularity in the resulting trophic network. A. spinosa and E. matador consume a significantly higher richness of prey items than their congeners. This result corresponds with non-random distributions and co-occurrence patterns in both species pairs: the two high prey richness species (A. spinosa and E. matador) co-occur more frequently than predicted by chance, but they are exclusive to exposed forereef sites with high wave action. In contrast, their congeners occur across exposed forereef and sheltered backreef sites, but they do not increase in numbers at sheltered sites. Our findings suggest that A. spinosa and E. matador monopolize a wide variety of prey in exposed habitats, but they are unable to meet the energetic demands of their adaptation to high-flow habitats in sheltered areas, possibly due to lower prey availability. This, in turn, indicates strong ecological differentiation among closely related species of cryptobenthic fishes, driven by links between diet, physiology, prey availability, and wave exposure.
... So, analysis of nuclear DNA variations will save the ultimate resolution of phylogeny studies. They found that the phylogenetic relations among fish species based on nuclear DNA locus could be efficient in phylogenetic studies [12][13][14][15] . ...
Developing informative DNA markers facilitate understanding of the evolution of parrotfish biological resources. Therefore, we present a comparative analysis among a group of tmo-4C4 gene fragment sequences identified in some parrotfish species (Scarus russelii, S. ghobban, S. ferrugineus, S. fuscopurpureus, S. psittacus and Chlorurus sordidus) and other tmo-4C4 gene sequences (obtained from NCBI). Nucleotide composition, sequence conservation, single nucleotide polymorphism and nucleotide diversity were calculated in all estimated DNA sequences. The evaluated fishes were clustered into two groups (Scaridae and Labridae). The GC and GC3 contents in Scaridae were higher than in Labridae. Averages of genetic distances were 0.046 and 0.095 within Scaridae and Labridae respectively. Analysis of nucleotide variations was used to reconstruct phylogenetic relations among evaluated fish species. Maximum Likelihood and Neighbor-Joining methods on the resulting DNA sequences produced parallel topologies that confirm the monophyly of each evaluated fish family. S. psittacus is distantly related from both S. russelii and C. sordidus. The low distance was observed between S. psittacus and S. fuscopurpureus. The tmo-4C4 gene system provides a reliable solution for understanding parrotfish species biodiversity and evolution. This study provides a guide for future investigations within these aquatic biological resources in the Red Sea.
... Relationships of the six species of Coralliozetus are incompletely resolved due to conflicts in characters, however, the "total evidence" tree based on both molecular and morphological data (Lin & Hastings, 2011) is followed here (Fig. 5). Species-level relationships were hypothesized for Protemblemaria by Hastings (2001) using morphological characters (none sexually dimorphic), and for Acanthemblemaria most recently using genetic data by Eytan et al. (2012) but also using morphological data (60 characters, one sexually dimorphic) by Hastings (1990), Almany & Baldwin (1996), and Hastings & Robertson (1999). Species-level relationships within Emblemariopsis, Chaenopsis and Emblemaria have not been studied in detail and consequently are for the most part represented in this study as polytomies (Fig. 5). ...
Synopsis
The study of sexual differences provides insights into selective factors operating on males and females, especially for clades exhibiting varied levels of dimorphism. Sexual differences in morphology and coloration (melanophores) were compiled for 66 of the 89 species of tube blennies (Blenniiformes, Chaenopsidae) from the systematic literature and examination of preserved specimens. Chaenopsids include essentially monomorphic species and those in which males and females differ in as many as 17 morphological and 14 coloration features. While the sexes of most species differ in coloration (at least at the time of breeding), they are morphologically similar in Acanthemblemaria, Hemiemblemaria, and Lucayablennius. While other genera exhibit an intermediate level of dimorphism, species of Coralliozetus, Cirriemblemaria, and Emblemaria are dramatically dimorphic. Character maps on a phylogenetic hypothesis indicate that this extreme level of dimorphism evolved independently in these genera. A complex history of evolution is implied by examination of jaw length with both increases and decreases in one or both sexes leading to either dimorphism or monomorphism. Several features related to shelter defense are monomorphic in species where both sexes inhabit shelters, but dimorphic where only males occupy shelters. Other dimorphic features increase the conspicuousness of male courtship and aggressive displays.
... Not all speciation in the TEP is between offshore islands and the mainland, as sister species are also distributed latitudinally along the continental coast (Hastings, 2000;Riginos, 2005). In many cases, coastal speciation is observed in fishes with reduced dispersal capabilities, such as those with demersal eggs or short pelagic larval durations (e.g., blennies; Eytan, Hastings, Holland, & Hellberg, 2012;Lin & Hastings, 2011;Miller, Lin, & Hastings, 2016). However, this is not always the case, as fishes with high dispersal potential are hypothesized to have diverged in situ in coastal habitats, such as grunts (Bernal et al. 2017;Bernardi, Alva-Campbell, Gasparini, & Floeter, 2008;Rocha, Lindeman, Rocha, & Lessios, 2008;Tavera, Acero, Balart, & Bernardi, 2012), wrasses (Wainwright et al., 2018), and Prionurus surgeonfishes (Ludt, Rocha, Erdmann, & Chakrabarty, 2015). ...
A wide variety of species are distinguished by slight color variations. However, molecular analyses have repeatedly demonstrated that coloration does not always correspond to distinct evolutionary histories between closely related groups, suggesting that this trait is labile and can be misleading for species identification. In the present study, we analyze the evolutionary history of sister species of Prionurus surgeonfishes in the Tropical Eastern Pacific (TEP), which are distinguished by the presence or absence of dark spots on their body. We examined the species limits in this system using comparative specimen‐based approaches, a mitochondrial gene (COI), more than 800 nuclear loci (Ultraconserved Elements), and abiotic niche comparisons. The results indicate there is a complete overlap of meristic counts and morphometric measurements between the two species. Further, we detected multiple individuals with intermediate spotting patterns suggesting that coloration is not diagnostic. Mitochondrial data recovered a single main haplotype shared between the species and all locations resulting in a complete lack of structure (ΦST = 0). Genomic analyses also suggest low levels of genetic differentiation (FST = 0.013), and no alternatively fixed SNPs were detected between the two phenotypes. Furthermore, niche comparisons could not reject niche equivalency or similarity between the species. These results suggest that these two phenotypes are conspecific and widely distributed in the TEP. Here, we recognize Prionurus punctatus Gill 1862 as a junior subjective synonym of P. laticlavius (Valenciennes 1846). The underlying causes of phenotypic variation in this species are unknown. However, this system gives insight into general evolutionary dynamics within the TEP.
... Mc1r gene was amplified using the conserved primers MC1RFor and MC1RRev ofEytan, Hastings, Holland, and Hellberg (2012). PCRs were performed in 15 ll reactions of 7.5 ll BioMix Red (Bioline), 0.3 ll of each primer (10 lM), 5.9 ll deionized water and 1 ll of gDNA with the following cycles: 1 cycle of 94°C for 45 s, 50°C for 45 s, 72°C for 90 s followed by 35 cycles of 95°C for 1 min, 63°C for 1 min and 72°C for 90 s, and a final cycle of 94°C for 40 s, 50°C for 45 s and 72°C for 10 min. ...
... The most basal relationships within the clade containing Axoclinus, Enneanectes and Crocodilichthys are in the West Atlantic (Fig. 4). There are no putative trans-isthmian geminate pairs in this group, despite the occurrence of several other examples of transisthmian geminates among Neotropical blennies Eytan et al., 2012). Interestingly, the widespread E. carminalis is sister to the remaining Pacific members of this clade. ...
... These include three pairs of transisthmian geminate species: one species pair of Abudefduf and one of Chromis (both Pomacentridae), and one of Ophioblennius (Blenniidae) (see Bermingham et al., 1997;Muss et al., 2001). The single Atlantic and Pacific representatives of Acanthemblemaria belonged to the same clade, but are not geminate sisters (Eytan et al., 2012). The single Pacific species of Coryphopterus is not the geminate sister of any of the three Caribbean species (J Van Tassell, pers. ...
Effects of planktonic food supplies and temperature on pelagic fish larvae are thought to be the primary environmental determinants of adaptive variation in egg size. Differences between the Atlantic and Pacific coasts of Panama in primary production (higher in the Pacific due to upwelling) and temperature (less seasonal in the non-upwelling Caribbean) allow testing such ideas. We compared the volumes, dry weights, and energy content of eggs of 24 species of reef fishes from the two sides of the isthmus during the cool and warm seasons. Both egg volume and egg dry weight were good predictors of egg energy content among species, although not within species. Caribbean species produced larger eggs than their close relatives in the Pacific. In the Pacific, eggs were significantly larger during the cool upwelling season than during the warm, non-upwelling period, with a similar but weaker seasonal pattern evident in the Caribbean. The production of larger eggs in the low-productivity Caribbean is consistent with the hypothesis that species produce larger eggs and offspring when larval food supplies are lower. Parallel patterns of seasonal variation in eggs size and the greater strength of that relationship in the Pacific indicate that temperature drives seasonal variation in egg size within species. The decline in egg size with increasing temperature, a general pattern among ectotherms, may be a physiological side-effect, due to differing effects of temperature on various metabolic processes during oogenesis or on hormones that influence growth and reproduction. Alternatively, the seasonal pattern may be adaptive in these fishes, by affecting larval performance or maintaining a particular timeline of major events during embryonic development.
