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.

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.

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.

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 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.

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.