Alpheus Hyatt Verrill

Aim To estimate patterns of potential species richness (PSR) and identify shallow‐water Ophiuroidea hotspots based on their modelled distribution throughout the eastern Pacific Ocean (EP).LocationEastern Pacific Ocean.TaxonEchinodermata: Ophiuroidea.MethodsWe compiled and analysed the occurrence of 137 shallow‐water (≤200 m) species of Ophiuroidea from the EP using Species Distribution Models (SDM; use of Maxent) and buffering for rare species to create the first maps of PSR of the class in the EP to gain insight into their patterns.ResultsThe highest PSR was found in mid‐latitudes, decreasing towards high latitudes, denoting a robust latitudinal pattern. All PSR hotspots were found in mid‐latitudes and correspond to northern Mexico, the area between Corinto (Nicaragua) and the Gulf of Panama, and the Galapagos Islands. The pattern is mainly linked to topographic configuration, although the models also suggest temperature and other environmental factors as important. Additionally, the pattern correlates (R = 98) with the pattern of the family Amphiuridae, suggesting that its richness can be used as a proxy for exploring Ophiuroidea richness patterns elsewhere.Main ConclusionsThe richness of Ophiuroidea from the EP follows a latitudinal pattern as do other invertebrate groups. The Gulf of California, Central America, and Galapagos Islands are confirmed as hotspots of Ophiuroidea richness. However, other significant areas include the west coast of southern Baja California, Chiapas, Guatemala, and Nicaragua. PSR patterns are influenced by diverse environmental variables and the distribution patterns of the most conspicuous families. SDMs are useful for understanding large‐scale distribution patterns. This work is the first PSR assessment of marine invertebrates from the EP.

Many studies have quantified ecological impacts of individual foundation species (FS). However, emerging data suggest that FS often co‐occur, potentially inhibiting or facilitating one another, thereby causing indirect, cascading effects on surrounding communities. Furthermore, global warming is accelerating, but little is known about how interactions between co‐occurring FS vary with temperature.Shallow aquatic sedimentary systems are often dominated by three types of FS: slower‐growing clonal angiosperms, faster‐growing solitary seaweeds, and shell‐forming filter‐ and deposit‐feeding bivalves. Here, we tested the impacts of one FS on another by analyzing manipulative interaction experiments from 148 papers with a global meta‐analysis.We calculated 1,942 (non‐independent) Hedges’ g effect sizes, from 11,652 extracted values over performance responses, such as abundances, growths or survival of FS, and their associated standard deviations and replication levels. Standard aggregation procedures generated 511 independent Hedges’ g that was classified into six types of reciprocal impacts between FS.We found that (i) seaweeds had consistent negative impacts on angiosperms across performance responses, organismal sizes, experimental approaches, and ecosystem types; (ii) angiosperms and bivalves generally had positive impacts on each other (e.g., positive effects of angiosperms on bivalves were consistent across organismal sizes and experimental approaches, but angiosperm effect on bivalve growth and bivalve effect on angiosperm abundance were not significant); (iii) bivalves positively affected seaweeds (particularly on growth responses); (iv) there were generally no net effects of seaweeds on bivalves (except for positive effect on growth) or angiosperms on seaweeds (except for positive effect on ‘other processes’); and (v) bivalve interactions with other FS were typically more positive at higher temperatures, but angiosperm‐seaweed interactions were not moderated by temperature.Synthesis: Despite variations in experimental and spatiotemporal conditions, the stronger positive interactions at higher temperatures suggest that facilitation, particularly involving bivalves, may become more important in a future warmer world. Importantly, addressing research gaps, such as the scarcity of FS interaction experiments from tropical and freshwater systems and for less studied species, as well as testing for density‐dependent effects, could better inform aquatic ecosystem conservation and restoration efforts and broaden our knowledge of FS interactions in the Anthropocene.

Ophiuroidea is one of the most suitable marine groups for exploring diversity partitioning in the ocean due to its wide distribution and particular lifestyles. Nevertheless, diversity and its variation have yet to be investigated, and even basic information for large areas such as the eastern tropical Pacific (ETP) is still lacking. The present contribution explores α, β, and γ-diversity patterns of Ophiuroidea from the ETP at four spatial scales (Operational Geographic Units, Ecoregions, Provinces, and Realms). Based on literature records, databases, and scientific collections, an occurrence matrix was constructed for 69 shallow water (0–200 m) Ophiuroidea of the ETP (Mexico–Peru). Diversity evaluation based on rarefaction curves indicated that the observed richness tends to reach the asymptote. At the province and the ecoregion levels, β-diversity was the most important component explaining γ-diversity. The components that mainly contributed to the differentiation between provinces and ecoregions were the intersection of nestedness and β-diversity. PERMANOVA and SIMPER results showed that species composition presented significant differences at all spatial levels. The PCO ordination indicated that the first component (PCO1) explained the variation in species composition in a longitudinal gradient between coastal and oceanic ecoregions, while PCO2 showed a latitudinal gradient. The shade plot yielded three clusters (northern, southern, and widely distributed species). In general, α-diversity was explained by differences in sampling effort and methods; in contrast, β-diversity and its components were mainly explained by patterns and processes occurring at different spatial scales (provinces and ecoregions) such as oceanographic conditions, geographic extension, dispersal, and environmental heterogeneity. This work represents the first attempt to analyze the distribution patterns of shallow-water Ophiuroidea from the ETP.

Understanding what determines range expansion or extinction is crucial to predict the success of biological invaders. We tackled this long-standing question from an unparalleled perspective using the failed expansions in Littorina saxatilis and investigated its present and past habitat suitability in Europe through Ecological Niche Modelling. This intertidal snail is a typically successful Atlantic colonizer and the earliest confirmed alien species in the Mediterranean Sea, where, however, it failed to thrive despite its high dispersal ability and adaptability. We explored the environmental constraints affecting its biogeography, identified potential glacial refugia in Europe that fuelled its post-glacial colonisations and tested whether the current gaps in its distribution are linked to local ecological features. Our results suggested that L. saxatilis is unlikely to be a glacial relict in the Mediterranean basin. Multiple Atlantic glacial refugia occurred in the Last Glacial Maximum, and abiotic environmental features such as salinity and water temperature have influenced the past and current distributions of this snail and limited its invasion of the Mediterranean Sea. The snail showed a significant overlap in geographic space and ecological niche with Carcinus maenas , the Atlantic predator, but distinct from Pachygrapsus marmoratus , the Mediterranean predator, further pointing to Atlantic-like habitat requirements for this species. Abiotic constrains during introduction rather than dispersal abilities have shaped the past and current range of L. saxatilis and help explaining why some invasions have not been successful. Our findings contribute to clarifying the processes constraining or facilitating shifts in species’ distributions and biological invasions.

Understanding how emergent ecological assemblages have diverged from natural states is fundamental in predicting future functioning and services of ecosystems. Coral reefs are of particular concern due to their high susceptibility to anthropogenic stressors. Yet, little is known about their pre-dist…

Mollusca is the largest marine phylum, comprising about 23% of all named marine organisms, Mollusca systematics are still in flux, and an increase in human activities has affected Molluscan reproduction and development, strongly impacting diversity and classification. Therefore, it is necessary to e…

During the Quaternary, large climate oscillations impacted the distribution and demography of species globally. Two approaches have played a major role in reconstructing changes through time: Bayesian Skyline Plots (BSPs), which reconstruct population fluctuations based on genetic data, and Species …

The latitudinal gradient of increasing marine biodiversity from the poles to the tropics is one of the most conspicuous biological patterns in modern oceans.1, 2, 3 Low-latitude regions of the global ocean are often hotspots of animal biodiversity, yet they are set to be most critically affected b…

Phyllodocida is a clade of errantiate annelids characterized by having ventral sensory palps, anterior enlarged cirri, axial muscular proboscis, compound chaetae (if present) with a single ligament, and of lacking dorsolateral folds. Members of most families date back to the Carboniferous, although …

Factors driving the spatial configuration of centres of endemism have long been a topic of broad interest and debate. Due to different eco‐evolutionary processes, these highly biodiverse areas may harbour different amounts of ancient and recently diverged organisms (paleo‐ and neo‐endemism, respecti…