Introgression of the Gamete Recognition Molecule, Bindin, in the Sea Urchin Diadema.

Hybridization is important in evolution, because it is a necessary (though not sufficient) step in the introgression of potentially adaptive variation between species. Bindin is a gamete recognition protein in echinoids and asteroids, capable of blocking cross-fertilization between species to varying degrees. Four species of the sea urchin genus Diadema are broadly sympatric in the Indo-Pacific: D.

Taxonomic reassessment of Tetrapygus niger (Arbacioida, Echinoidea): molecular and morphological evidence support its placement in Arbacia.

The echinoid genus Tetrapygus was initially described by L. Agassiz (1841) based on a single species, Tetrapygus niger Molina, 1782. Since the extensive work conducted by Mortensen (1935), Tetrapygus has received limited taxonomic attention over the past century.

Near-Chromosomal-Level Genome Assembly of the Sea Urchin Echinometra lucunter, a Model for Speciation in the Sea.

Echinometra lucunter, the rock-boring sea urchin, is a widely distributed echinoid and a model for ecological studies of reproduction, responses to climate change, and speciation. We present a near chromosome-level genome assembly of E. lucunter, including 21 scaffolds larger than 10 Mb predicted to represent each of the chromosomes of the species.

A scuticociliate causes mass mortality of in the Caribbean Sea.

Echinoderm mass mortality events shape marine ecosystems by altering the dynamics among major benthic groups. The sea urchin , virtually extirpated in the Caribbean in the early 1980s by an unknown cause, recently experienced another mass mortality beginning in January 2022. We investigated the cause of this mass mortality event through combined molecular biological and veterinary pathologic approaches comparing grossly normal and abnormal animals collected from 23 sites, representing locations that were either affected or unaffected at the time of sampling.

Mitochondrial phylogeny of the brittle star genus Ophioderma.

We reconstructed the mitochondrial phylogeny of the species of the brittle star genus Ophioderma, using sequences of the Cytochrome Oxidase I gene (COI) to address four questions: (i) Are the species of Ophioderma described on morphological evidence reflected in mitochondrial genealogy? (ii) Which species separated from which? (iii) When did speciation events occur? (iv) What is the rate of COI evolution in ophiuroids? We found that most of the 22 described species we sampled coincide with monophyletic clusters of COI sequences, but there are exceptions, most notably in the eastern Pacific, in which three undescribed species were indicated. The COI phylogeny lacks resolution in the deeper nodes, but it does show that there are four species pairs, the members of which are found on either side of the central American Isthmus. Two pairs with a genetic distance of ~ 4% between Atlantic and Pacific members were probably split during the final stages of Isthmus completion roughly 3 million years ago.

Phylogeography, colouration, and cryptic speciation across the Indo-Pacific in the sea urchin genus Echinothrix.

The sea urchins Echinothrix calamaris and Echinothrix diadema have sympatric distributions throughout the Indo-Pacific. Diverse colour variation is reported in both species. To reconstruct the phylogeny of the genus and assess gene flow across the Indo-Pacific we sequenced mitochondrial 16S rDNA, ATPase-6, and ATPase-8, and nuclear 28S rDNA and the Calpain-7 intron.

Slow evolution under purifying selection in the gamete recognition protein bindin of the sea urchin Diadema.

Bindin is a sperm protein that mediates attachment and membrane fusion of gametes. The mode of bindin evolution varies across sea urchin genera studied to date. In three genera it evolves under positive selection, in four under mostly purifying selection, and in one, results have been mixed.

Predominant east to west colonizations across major oceanic barriers: Insights into the phylogeographic history of the hydroid superfamily Plumularioidea, suggested by a mitochondrial DNA barcoding marker.

We provide preliminary insights into the global phylogeographic and evolutionary patterns across species of the hydrozoan superfamily Plumularioidea (Cnidaria: Hydrozoa). We analyzed 1,114 16S sequences of 198 putative species of Plumularioidea collected worldwide. We investigated genetic connections and divergence in relation to present-day and ancient biogeographic barriers, climate changes and oceanic circulation.

Marine species formation along the rise of Central America: The anomuran crab Megalobrachium.

The evolution of marine neotropical shallow water species is expected to have been greatly affected by physical events related to the emergence of the Central American Isthmus. The anomuran crab Megalobrachium, a strictly neotropical porcellanid genus, consists of four species in the West Atlantic (WA) and nine in the East Pacific (EP). Dispersal is limited to a relatively short planktonic phase, which lasts approximately two weeks.

Hundreds of genetic barcodes of the species-rich hydroid superfamily Plumularioidea (Cnidaria, Medusozoa) provide a guide toward more reliable taxonomy.

Marine hydroids are important benthic components of shallow and deep waters worldwide, but their taxonomy is controversial because diagnostic morphological characters to categorize taxa are limited. Their genetic relationships are also little investigated. We tested taxonomic hypotheses within the highly speciose superfamily Plumularioidea by integrating a classical morphological approach with DNA barcoding of the 16S and COI mitochondrial markers for 659 and 196 specimens of Plumularioidea, respectively.

A phylogenomic resolution of the sea urchin tree of life.

Background: Echinoidea is a clade of marine animals including sea urchins, heart urchins, sand dollars and sea biscuits. Found in benthic habitats across all latitudes, echinoids are key components of marine communities such as coral reefs and kelp forests. A little over 1000 species inhabit the oceans today, a diversity that traces its roots back at least to the Permian.

Molecular signatures of host specificity linked to habitat specialization in sea anemones.

Rising ocean temperatures associated with global climate change induce breakdown of the symbiosis between coelenterates and photosynthetic microalgae of the genus . Association with more thermotolerant partners could contribute to resilience, but the genetic mechanisms controlling specificity of hosts for particular types are poorly known. Here, we characterize wild populations of a sea anemone laboratory model system for anthozoan symbiosis, from contrasting environments in Caribbean Panama.

Highly contrasted population genetic structures in a host-parasite pair in the Caribbean Sea.

Evolution and population genetic structure of marine species across the Caribbean Sea are shaped by two complex factors: the geological history and the present pattern of marine currents. Characterizing and comparing the genetic structures of codistributed species, such as host-parasite associations, allow discriminating the relative importance of environmental factors and life history traits that influenced gene flow and demographic events. Using microsatellite and Cytochrome Oxidase I markers, we investigated if a host-parasite pair (the heart urchin and its parasitic pea crab ) exhibits comparable population genetic structures in the Caribbean Sea and how the observed patterns match connectivity regions from predictive models and other taxa.

Phylogeography of the sand dollar genus Encope: implications regarding the Central American Isthmus and rates of molecular evolution.

Vicariant events have been widely used to calibrate rates of molecular evolution, the completion of the Central American Isthmus more extensively than any other. Recent studies have claimed that rather than the generally accepted date of ~3 million years ago (Ma), the Isthmus was effectively complete by the middle Miocene, 13 Ma. We present a fossil calibrated phylogeny of the new world sand dollar genus Encope, based on one nuclear and four mitochondrial genes, calibrated with fossils at multiple nodes.

Phylogeography of Petrolisthes armatus, an invasive species with low dispersal ability.

Theoretically, species with high population structure are likely to expand their range, because marginal populations are free to adapt to local conditions; however, meta-analyses have found a negative relation between structure and invasiveness. The crab Petrolisthes armatus has a wide native range, which has expanded in the last three decades. We sequenced 1718 bp of mitochondrial DNA from native and recently established populations to determine the population structure of the former and the origin of the latter.

Spatial Ecology of the American Crocodile in a Tropical Pacific Island in Central America.

Conservation of large predators has long been a challenge for biologists due to the limited information we have about their ecology, generally low numbers in the wild, large home ranges and the continuous expansion of human settlements. The American crocodile (Crocodylus acutus) is a typical apex predator, that has suffered from all of these characteristic problems, especially the latter one. Humans have had a major impact on the recovery of this species throughout its range, even though most of the countries it inhabits have banned hunting.

The evolution of larval developmental mode: insights from hybrids between species with obligately and facultatively planktotrophic larvae.

Life history characteristics play a pervasive role in the ecology and evolution of species. Transitions between feeding and non-feeding larval development have occurred many times in both terrestrial and marine phyla, however we lack a comprehensive understanding of how such shifts occur. The sea biscuits Clypeaster rosaceus and Clypeaster subdepressus employ different life history strategies (facultatively feeding larvae and obligately feeding larvae, respectively) but can hybridize.

The Great Diadema antillarum Die-Off: 30 Years Later.

In 1983-1984, the sea urchin Diadema antillarum suffered mass mortality throughout the Caribbean, Florida, and Bermuda. The demise of this herbivore contributed to a phase shift of Caribbean reefs from coral-dominated to alga-dominated communities. A compilation of published data of D.

Evolution of gamete attraction molecules: evidence for purifying selection in speract and its receptor, in the pantropical sea urchin Diadema.

Many free-spawning marine invertebrates, such as sea urchins, lack any courtship or assortative mating behavior. Mate recognition in such cases occur at the gametic level, and molecules present on the sperm and egg are major determinants of species-specific fertilization. These molecules must also coevolve in relation to each other in order to preserve functional integrity.

Phylogeography of the sand dollar genus Mellita: cryptic speciation along the coasts of the Americas.

Sand dollars of the genus Mellita are members of the sandy shallow-water fauna. The genus ranges in tropical and subtropical regions on the two coasts of the Americas. To reconstruct the phylogeography of the genus we sequenced parts of the mitochondrial cytochrome oxidase I and of 16S rRNA as well as part of the nuclear 28S rRNA gene from a total of 185 specimens of all ten described morphospecies from 31 localities.