There is a need for improvement and standardization in larval descriptions for them to become useful not only for identification purposes but also in comparative and phylogenetic studies. Details of the rearing technique and equipment used should be given, the spent female crab and representative larval stages need to be deposited at a national museum and a minimum of five specimens of each stage should he used for meristic and morphometric criteria. Diagnostic features of the carapace, all appendages, abdomen, and other characters that are to be included in a standard larval description are presented with specifications concerning format and sequence of substructures. Typical configurations of larval structures are given and some possible exceptions are described. Guidelines for illustrations including the preparation, size, sequence and arrangement of figures are provided.

This study examined echinoderm assemblages from nearshore rocky habitats for large-scale distribution patterns with specific emphasis on identifying latitudinal trends and large regional hotspots. Echinoderms were sampled from 76 globally-distributed sites within 12 ecoregions, following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org). Sample-based species richness was overall low (<1–5 species per site), with a total of 32 asteroid, 18 echinoid, 21 ophiuroid, and 15 holothuroid species. Abundance and species richness in intertidal assemblages sampled with visual methods (organisms >2 cm in 1 m2 quadrats) was highest in the Caribbean ecoregions and echinoids dominated these assemblages with an average of 5 ind m−2. In contrast, intertidal echinoderm assemblages collected from clearings of 0.0625 m2 quadrats had the highest abundance and richness in the Northeast Pacific ecoregions where asteroids and holothurians dominated with an average of 14 ind 0.0625 m−2. Distinct latitudinal trends existed for abundance and richness in intertidal assemblages with declines from peaks at high northern latitudes. No latitudinal trends were found for subtidal echinoderm assemblages with either sampling technique. Latitudinal gradients appear to be superseded by regional diversity hotspots. In these hotspots echinoderm assemblages may be driven by local and regional processes, such as overall productivity and evolutionary history. We also tested a set of 14 environmental variables (six natural and eight anthropogenic) as potential drivers of echinoderm assemblages by ecoregions. The natural variables of salinity, sea-surface temperature, chlorophyll a, and primary productivity were strongly correlated with echinoderm assemblages; the anthropogenic variables of inorganic pollution and nutrient contamination also contributed to correlations. Our results indicate that nearshore echinoderm assemblages appear to be shaped by a network of environmental and ecological processes, and by the differing responses of various echinoderm taxa, making generalizations about the patterns of nearshore rocky habitat echinoderm assemblages difficult.

Physical characteristics of pockmarks in Passamaquoddy Bay, Bay of Fundy, Canada were measured, including depth, benthic area, sidewall slope, orientation at longest diameter and an out-of-roundness estimate. Sedimentary holes of uncertain origin, ranging from 2.69 to 36.02 cm 2 in area, were discovered. Mean densities of 4.78 holes m-2 inside and 3.88 holes m-2 outside pockmarks were found. Geochemical measurements of cores of ~100 cm depth suggested that sedimentary microbial metabolism was different inside than outside pockmarks. The megabiota consisted of the sea star Asterias rubens, commonest outside pockmarks; the sea cucumber Cucumaria frondosa, commonest on pockmark bottoms; an unidentified bryozoan/hydrozoan and the filamentous bacterium Beggiatoa sp., commonest on pockmark sidewalls. During this study, 2 habitat types (A and B) were characterized by differences in (1) multibeam acoustic data, and (2) community structure. Two different patterns of benthic macro-infaunal community structure were related to upper and lower areas within Habitat A. Compared to reference sites, upper Habitat A pockmarks had significantly fewer species and lower densities. Consequently, pockmark community structure was also different, notably with absence or lower densities of taxa appearing late in the succession. Lower Habitat A pockmarks had smaller and more subtle differences in macro-infaunal community structure than reference locations outside pockmarks and the equilibrium species number varied with benthic area of each pockmark. Circumstantial evidence, including nMDS and species-area plots, dominance patterns, accumulated species number and density of benthic macrofaunal communities, supports the hypothesis that upper Habitat A pockmarks are at various stages in a pre-equilibrium succession. By contrast, all lower Habitat A pockmarks had already reached equilibrium levels.

Assemblages associated with intertidal rocky shores were examined for large scale distribution patterns with specific emphasis on identifying latitudinal trends of species richness and taxonomic distinctiveness. Seventy-two sites distributed around the globe were evaluated following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org). There were no clear patterns of standardized estimators of species richness along latitudinal gradients or among Large Marine Ecosystems (LMEs); however, a strong latitudinal gradient in taxonomic composition (i.e., proportion of different taxonomic groups in a given sample) was observed. Environmental variables related to natural influences were strongly related to the distribution patterns of the assemblages on the LME scale, particularly photoperiod, sea surface temperature (SST) and rainfall. In contrast, no environmental variables directly associated with human influences (with the exception of the inorganic pollution index) were related to assemblage patterns among LMEs. Correlations of the natural assemblages with either latitudinal gradients or environmental variables were equally strong suggesting that neither neutral models nor models based solely on environmental variables sufficiently explain spatial variation of these assemblages at a global scale. Despite the data shortcomings in this study (e.g., unbalanced sample distribution), we show the importance of generating biological global databases for the use in large-scale diversity comparisons of rocky intertidal assemblages to stimulate continued sampling and analyses.

Latitudinal gradients in species abundance and diversity have been postulated for nearshore taxa but few analyses have been done over sufficiently broad geographic scales incorporating various nearshore depth strata to empirically test these gradients. Typically, gradients are based on literature reviews and species lists and have focused on alpha diversity across the entire nearshore zone. No studies have used a standardized protocol in the field to examine species density among sites across a large spatial scale while also focusing on particular depth strata. The present research used field collected samples in the northern hemisphere to explore the relationships between macroalgal species density and biomass along intertidal heights and subtidal depths and latitude. Results indicated no overall correlations between either estimates of species density or biomass with latitude, although the highest numbers of both were found at mid-latitudes. However, when strata were examined separately, significant positive correlations were found for both species numbers and biomass at particular strata, namely the intertidal ones. While the data presented in this paper have some limitations, we show that latitudinal macroalgal trends in species density and biomass do exist for some strata in the northern hemisphere with more taxa and biomass at higher latitudes.

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Comparative larval morphology was used to elucidate phylogenetic relationships within the Pinnotheridae and the Dissodactylus species complex. Within the family, seven zoeal and six megalopal characters suggested two equally parsimonious phylogenetic hypotheses for pinnotherid larvae, both with Ostracotheres tridacnae representing the sister group for the Dissodactylus complex. Results indicated that the genus Pinnotheres is a polyphyletic taxon, and that the traditional subfamilial arrangement comprises paraphyletic taxa within the subfamilies Pinnotherinae and Pinnothereliinae. Certain evidence has suggested that Fabia and Juxtafubia should be excluded from the Pinnotherinae and placed into the Pinnothereliinae. Larval and adult morphology suggested that Pinnotheres politus should be included within Tumidotheres. The phylogenetic analysis within the Dissodactylus complex involved one zoeal and 16 megalopal characters. Results suggested a single phylogenetic hypothesis based on larval morphology. Combining adult morphology with larval evidence resulted in two equally parsimonious phylogenetic hypotheses, one of which agreed with a previously suggested hypothesis based only on adult characters.