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Map of the Florida Keys showing the collection locations of Lee and O ́ Foighil (2004). 1 = Boca Chica Key, 2 = The horseshoe site on Spanish Harbor/West Summerland Key, and 3 = Key Biscayne. Upper left inset showing the Floridian peninsula. Lower left inset showing Long Key and collection locations of this study. S = seawall habitat location and M = mangrove habitat location.
Source publication
The nominal morphospecies Brachidontes exustus (Linnaeus, 1758) represents a cryptic species complex with multiple genetic disjunctions resulting in regionally dominant, but range-restricted, species throughout the western Atlantic, Caribbean, and Gulf of Mexico. In the Florida Keys, four spe-cies were previously identified using molecular techniqu...
Contexts in source publication
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... and O ´ Foighil (2004) collected nominal Brachidontes exustus from three rocky intertidal sites from the Florida Keys (Figure 1). The Bahamian and Gulf species were most commonly encountered. ...
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... Key, a 6-km long Y-shaped island in approxi- mately the middle of the Florida Keys archipelago, has an interior lagoon fringed by mangroves with a connec- tion to the bayside of the island (Figure 1). The nearest mile marker on US Route 1 serves as a useful universal landmark for the Florida Keys and the number of the nearest mile marker is included with the collection loca- tions. ...
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... first collection location (latitude 24 48.10 N, longi- tude 80 50.58 W) is an ocean-side vertical concrete sea- wall near mile marker 66 at the west end of Long Key, adjacent to the Long Key Viaduct (Figure 1). The lowest intertidal zone of the seawall is approximately 1 m above a sandy bottom. ...
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... col- lected from the seawall were thicker with more robust ribbing and were wider across both valves compared to shells of similar length collected from the mangrove hab- itat. When viewed laterally, the overall shell outline of the seawall specimens was more modioliform (Figures 3 through 6), while the mangrove specimens were more mytiliform (Figures 7 through 14). For the seawall spec- imens, the anterior margin was more rounded, the umbo in a more dorsal orientation, and the overall ventral- dorsal margin angle less than in specimens of similar size from the mangrove. ...
Citations
... But an analysis of the four species comprising nearly 75% of the total abundance suggest that it is not the case in our study: Tanais dulongii and Leptocheirus rhizophorae are brooding crustaceans with benthic life cycles and low dispersion rates (Rumbold et al. 2015;Arfianti 2020). In turn, while Brachidontes domingensis and Crassostrea rhizophorae are broadcast spawners, C. rhizophorae have short-lived larvae (10-12 d; Rampersad and Ammons 1992) and although B. dominguensis does have long larval stage it commonly display heterogeneous spatial distributions at local stages (Bennett et al. 2011). ...
Urbanization represents a radical transformation of natural habitats that alters all the biotic and abiotic properties governing ecosystems. Urban expansion often results in oversimplified communities, where most specialists decline or disappear and a few generalist or exotic species become dominant. The consequences of urban expansion in mangrove forests are understudied, although these systems have been altered by humans for centuries and the growth of human population in tropical coasts is expected to be faster than in higher latitudes. To assess the importance of indigenous and non-indigenous species in driving temporal and spatial changes in community structure of red-mangrove prop-root macrobenthic communities, we studied heavily altered mangrove forests from two bays from the Caribbean coast of Colombia in 2005 and 2021. In all places/periods, the community richness was low, a few taxa were dominant (11 taxa, out of 40, comprised ~ 90% of the total abundance) and 35% of those taxa were non-indigenous species whose presence is related with known stressors in urbanized systems. Hence, call for efforts to assess whether urban mangrove forests are emerging as hotspots for non-indigenous biota. Community structure did not change within or between bays, there was a clear, significant turnover of core species between 2005 and 2021, with non-indigenous species playing a prominent role in this variability. This was puzzling—ecological theory asserts that the abundance of a species is related to their permanence: core species are relatively stable through time, while rare species appear or disappear—but this may not apply for stressed communities influenced by non-indigenous biota.
... The genus Brachidontes (Swainson, 1840) originated in the Jurassic (Morton, 2012) and is a near-worldwide genus of scorched mussels living on natural and rigid artificial substrates of shallow waters (Aguirre et al., 2006). It is represented by ecomorphs controlled by temperature, substrate, energy, water depth, and salinity (Aguirre et al., 2006;Trovant et al., 2013); and it has a wide variety of habitats, inhabiting brackish waters of river outlets, estuaries, mangrove swamps (Bennett et al., 2011;Morton, 2012) and marine coastal to open ocean (Rios and Barcellos, 1979;Lee and Foighil, 2004;Trovant et al., 2013Trovant et al., , 2015Trovant et al., , 2016. ...
... However, the lack of morphological diagnostic characters to distinguish the species correctly made it necessary to use molecular markers to determine the taxonomic status of different ecotypes. Foighil (2004, 2005) and Bennett et al. (2011), using molecular markers for populations from Florida and the Caribbean Sea, concluded that B. exustus is a complex of species rather than a single species; identifying four distinct genetic clades: the Atlantic, the Gulf of Mexico, The Bahamas and Antilles clades Foighil, 2004, 2005). Trovant et al. (2013) enhanced the need to resolve the taxonomic status of the South American Brachidontes species and demonstrated by molecular markers the specific status of B. darwinianus, B. rodriguezi and B. purpuratus for the south western Atlantic. ...
Brachidontes exustus (Mollusca, Mytilidae) is mainly distributed in Central America, where it has been recognized as a _lataforma species. This study aimed to determine whether B. exustus extends beyond the Amazon Barrier and southward along the Brazilian West Atlantic coast. Mitochondrial genes coding for cytochrome-c oxidase, subunit I (COI) and 16S subunit of ribosomal _lataforma__ cid (16S rRNA) were analyzed with _lata parameters on Brazilian populations (Salvador, Arraial do Cabo and Fernando de Noronha) of scorched mussels previously recorded as B. exustus. Multivariate morphometric _latafor showed partial discrimination of species. Molecular _latafor confirmed B. exustus at Salvador, a population highly similar to Cartagena (Colombia), both belonging to the Atlantic Clade of the B. exustus complex. This fact adds evidence to the idea of the Amazon outflow as a semipermeable barrier. In the southeast of Brazil, B. exustus was not found; instead, B. darwinianus is the species represented at Arraial do Cabo (state of Rio de Janeiro), associated with brackish _lataf. Scorched mussels from Fernando de Noronha are most closely related to B. puniceus from Cape Verde with 4.4% differentiation. Demonstrating an independent evolutionary history since at least the beginning of the Pleistocene, its proposed new name is B. noronhensis.
... Although meta-analyses are not yet available, many genetically identified species prove to be morphologically separable on close examination, implying that modern morphology-based studies tend to capture most biological species [40,41]. Furthermore, cryptic species that have been discovered are not exclusively allopatric, and may be partially or fully nested within the geographical ranges of related species, even in the tropics [42,43]. Some tropical species show limited genetic divergence over vast distances in the Indo-West Pacific two different ways an increase in median range sizes towards high latitudes can be associated with more taxa in the tropics (turnover in a and nestedness in b), and one example whereby larger range sizes in the tropics are associated with more taxa in the tropics (c). ...
Many marine and terrestrial clades show similar latitudinal gradients in species richness, but opposite gradients in range size—on land, ranges are the smallest in the tropics, whereas in the sea, ranges are the largest in the tropics. Therefore, richness gradients in marine and terrestrial systems do not arise from a shared latitudinal arrangement of species range sizes. Comparing terrestrial birds and marine bivalves, we find that gradients in range size are concordant at the level of genera. Here, both groups show a nested pattern in which narrow-ranging genera are confined to the tropics and broad-ranging genera extend across much of the gradient. We find that (i) genus range size and its variation with latitude is closely associated with per-genus species richness and (ii) broad-ranging genera contain more species both within and outside of the tropics when compared with tropical-or temperate-only genera. Within-genus species diversification thus promotes genus expansion to novel latitudes. Despite underlying differences in the species range-size gradients, species-rich genera are more likely to produce a descendant that extends its range relative to the ancestor’s range. These results unify species richness gradients with those of genera, implying that birds and bivalves share similar latitudinal dynamics in net species diversification. © 2016 The Author(s) Published by the Royal Society. All rights reserved.
... A study of Brachidontes specimens from different wave exposures in the Florida Keys (Bennett & Willan, 2003) concluded that the observed morphological differences were the result of phenotypic plasticity, but the study was conducted before the presence of multiple cryptic species in the region was known and the observed morphological variation might well be a combination of genotypic constraints and phenotypic plasticity. A recent study by Bennett et al. (2011) has taken a closer look, by DNA barcoding, at specimens from seawall and mangrove substrata on Long Key and found them to belong to the Antillean and Gulf clades, respectively. The specimens in the present study were collected in Caulerpa (green algae) on mangrove roots in Lake Surprise, a brackish (salinity ca. ...
To broaden the anatomical knowledge of marine bivalves, detailed gross anatomical studies of 20 species from the Florida Keys are presented, representing 19 families: (Cardiidae) and Scissula similis (J. Sowerby, 1806) (Tellinidae). These taxa represent various clades of the class Bivalvia and interface with broader regional and phylogenetic studies (e.g., the Bivalve Tree of Life, http://www.bivatol.org, and Bivalves-in-Time-and-Space, http://www.bivatol.org/bits), in which many serve as exemplar species in different contexts. These descriptions provide the most complete anatomical descriptions yet presented for all species, most especially for Solemya occidentalis, Limopsis aff. cristata, Hyotissa mcgintyi, H. hyotis, Carditamera flori-dana, Entodesma beana, Chama macerophylla and Polymesoda floridana, for which no or only minimal anatomical information has been previously published. This work presents the first anatomical description of any species of Scissula, based on S. similis. Two controversial characters – the promyal passages (in Hyotissa spp., in Anomia simplex noted here for the first time, and in Crassostrea reported in the literature) and the various kinds of posterior apertures and siphons present in the species examined and across the Bivalvia – emphasize the need for further comparative study to confirm homologies. Conspecificity of Brazilian material with that from the North American coast is clarified for all species, resulting in nine species being removed from Brazilian checklists (S. occidentalis, B. exustus, I. alatus, P. carnea, C. floridana, C. macerophylla, L. hians, L. serratum, and S. similis). Pertinent anatomical characters are summarized in a data matrix, and an analysis is provided to demonstrate the utility and resolving power of such characters (but from this limited taxon sampling is not intended to provide a revised phylogenetic hypothesis of bivalve relationships); data for three additional species from Florida, published earlier, are included in the analysis and discussion.
Urbanization represent a radical transformation of natural habitats that alters all the biotic and abiotic properties governing ecosystems. Urban expansion often results in oversimplified communities, where most specialists decline or disappear and a few generalist or exotic species become dominant. The consequences of urban expansion in mangrove forests are understudied, although these systems have been altered by humans through centuries and the growth of human population in tropical coasts is expected to be faster than in higher latitudes. To assess the importance of indigenous and non-indigenous species in driving temporal and spatial changes in community structure of red-mangrove prop-root macrobenthic communities, we studied heavily altered mangrove forests from two bays from the Caribbean coast of Colombia in 2005 and 2021. In all places/periods, the community richness was low, a few taxa were dominant (11 taxa, out of 40, comprised ~ 90% of the total abundance) and the majority of all taxa (65%) were non-indigenous species whose presence is related with known stressors in urbanized systems. Hence, we suggest that urban mangrove forests are emerging hotspots for non-indigenous biota. Community structure did not change within or between bays, there was a clear, significant turnover of core species between 2005 and 2021, with non-indigenous species playing a prominent role in this variability. This was puzzling –ecological theory asserts that the abundance of a species is related to their permanence: core species are relatively stable through time while rare species appear or disappear– but this may not apply for communities dominated by non-indigenous biota.
Taxonomy of the pen shell (genus Atrina) in East Asia has been confused because of the plasticity of the shell morphology and lack of unified morphological characteristics. We analyzed the mitochondrial cytochrome c oxidase subunit I (COI) sequence of the pen shell sampled from Ariake Bay and Seto Inland Sea, western Japan. All individuals were identified as the scaly form based on external morphology, however, their COI sequences were comprised of two distinct lineages. The sequence divergence between the two was 8.3%, indicating the high possibility that they are different species. The scaly form of the pen shell in Japan is one of the target species for resource enhancement, therefore COI lineage identification of broodstock individuals is critically important to avoid producing hybrid seed. We developed a loop-mediated isothermal amplification (LAMP) method that enables specific detection of the two lineages. This method can contribute to reduce the cost and time required for genotyping broodstock individuals prior to seed production.
Explanations for major biodiversity patterns have not achieved a consensus, even for the latitudinal diversity gradient (LDG), but most relate to patterns of solar energy influx into Earth systems, and its effects on temperature (as biochemical activity rates are temperature sensitive) and photosynthesis (which drives nearly all of the productivity that fuels ecosystems). Marine systems break some of the confounding correlations among temperature, latitude and biodiversity that typify the terrestrial systems that have dominated theoretical discussions and large-scale analyses. High marine diversities occur not only in warm shallow seas where productivity may be either low or high, depending on regional features, but also in very cold deep-sea regions, indicating that diversity is promoted by stability in temperature and in trophic resources (nutrients and food items), and more specifically by their interaction, rather than by high mean values of either variable. The common association of high diversity with stable but low to moderate annual productivity suggests that ecological specialization underlies the similarly high diversities in the shallow tropics and deep sea. Recent work on shallow-marine bivalves is consistent with this view of decreasing specialization in less stable habitats. Lower diversities in shallow seas are associated with either high thermal seasonality (chiefly in temperate latitudes) or highly seasonal trophic supplies (at any latitude), which exclude species that are adapted to narrow ranges of those variables.
