Benthic hydroids (Cnidaria: Hydrozoa) from the Spanish Antarctic expedition Bentart 95

A total of 61 species of hydroids, belonging to 13 families and 23 genera, were found during the Spanish Antarctic expedition Bentart 95 with the RV Hespérides. Ten of the species were identified only to generic level. The dominance of the subclass Leptothecatae, with 57 species, was remarkable. The remaining four species belong to the subclass Anthoathecatae. By far the most diverse family was the Sertulariidae, with 25 species (41%), followed by Haleciidae with nine species (15%) and Kirchenpaueriidae with six (10%). The family Plumulariidae, represented by one species of Nemertesia, is recorded for the first time from Antarctic waters. Eudendrium scotti, Perarella clavata and Symplectoscyphus hero are each recorded for the second time. Symplectoscyphus with 11 species was the dominant genus. Almost 60% of the species diversity is concentrated in just a little more than the 20% of genera. Nearly 70% of the species are endemic to Antarctic waters and 90% of them are restricted to Antarctic or Antarctic/sub-Antarctic waters.     

Benthic hydroids (Cnidaria: Hydrozoa) from Peter I Island (Southern Ocean, Antarctica)

Twenty-three species of benthic hydroids, belonging to eight families and 13 genera, were found in a hydroid collection from Peter I Island, collected during both the Bentart 2003 and Bentart 2006 Spanish expeditions with BIO Hespérides in 2003 and 2006. Fourteen out of the 23 species constitute new records for Peter I Island, raising the total number of known species in the area to 30, as also do seven out of the 13 genera. The majority of the species are members of the subclass Leptothecata; the subclass Anthoathecata being scarcely represented. Sertulariidae is the family with the greatest number of species in the collection, with eight species (35%), followed by Lafoeidae with five (22%). Symplectoscyphus with four species (17%) and both Antarctoscyphus and Halecium with three (13%), including H. frigidum sp. nov., were the most diverse genera. Twenty species (ca. 77%) are endemic to Antarctic waters, either with a circum-Antarctic (11 species, ca. 42%) or West Antarctic (9 species, ca. 35%) distribution. Twenty-four (ca. 92%) are restricted to Antarctic or Antarctic/sub-Antarctic waters; only two species have a wider distribution. Peter I Island hydroid fauna is composed of typical representatives of the Antarctic benthic hydroid fauna, though it is characterized by the low representation of some of the most diverse and widespread Antarctic genera (Schizotricha and Staurotheca).     

First record of sympagic hydroids (Hydrozoa,Cnidaria) in Arctic coastal fast ice

We report on the first record of interstitial cnidarians in sea ice. Ice core samples were collected during eight field periods between February 2003 and June 2006 in the coastal fast ice off Barrow, Alaska (71°N, 156°W) at four locations. A total of 194 solitary, small (0.2–1.1 mm) elongated specimens of a previously unknown interstitial hydroid taxon were found. By cnidome composition and the occurrence of a highly retractable pedal disc formed by epidermal tissue only, the specimens are tentatively assigned to representatives of the family Protohydridae, subclass Anthomedusae. The hydroids were found almost exclusively in the bottom 10 cm-layer (at the ice–water interface) of 118 ice cores, with abundances ranging from 0 to 27 individuals per core section (0–4,244 ind m⁻²) and a grand mean of 269 ind m⁻² in bottom 10 cm-layer sections. Abundances were lower in December and late May than in months in between with considerable site variability. A factor analysis using 12 variables showed that hydroid abundance correlated highest with abundances of copepod nauplii and polychaete juveniles suggesting a trophic relationship.     

Evolution of Nemertesia hydroids (Cnidaria: Hydrozoa,Plumulariidae) from the shallow and deep waters of the NE Atlantic and western Mediterranean

Moura, C. J., Cunha, M. R., Porteiro, F. M., Yesson, C. & Rogers, A. D. (2011) Evolution of Nemertesia hydroids (Cnidaria: Hydrozoa, Plumulariidae) from the shallow and deep waters of the NE Atlantic and Western Mediterranean. —Zoologica Scripta, 41, 79–96. Hydroid species from the genus Nemertesia develop some of the largest and most complex hydrozoan colonies. These colonies are abundant and ecologically important in both shallow and deep waters worldwide. Here, we analyse the systematics of most Nemertesia species from the NE Atlantic and Mediterranean using morphology and phylogenetic inferences of 16S rRNA haplotype data. Phylogeographical analysis revealed multiple movements of taxa to and from the Mediterranean after the Messinian salinity crisis through shallow and deep waters. The nominal species Nemertesia belini and Nemertesia antennina revealed multiple genetic lineages representing cryptic species diversity. Molecular phylogenetic evidence was supported by consistent phenotypic differences between lineages, and three and seven putative species were resolved within the N. belini and N. antennina complexes, respectively. Three putative species of the N. antennina complex found at different seamounts of Azores grouped in a clade clustered amongst the other four cryptic species present at neighbouring bathyal localities of the Gulf of Cadiz. These cryptic species, mostly from the deep sea, form a clade distantly related to the typical N. antennina from European coastal waters. Depth or environmental correlates of depth seem to influence the reproductive strategies of Nemertesia colonies and ultimately speciation. In particular, speciation of these hydroids must have been influenced by hydrography, habitat heterogeneity, isolation by distance and larval dispersal capacity. The deep sea is shown as an important environment in the generation and accumulation of lineages that may occasionally invade coastal waters in the NE Atlantic. Glacial cycles of cooling, along with changes in sea level, and eradication of some coastal faunas likely facilitated speciation and evolutionary transitions from deep to shallow waters.     

DNA barcoding reveals cryptic diversity in marine hydroids (Cnidaria, Hydrozoa) from coastal and deep-sea environments

Fifty-six sequences of the mitochondrial 16S RNA gene were generated for hydroids, belonging to six nominal families — Eudendriidae, Lafoeidae, Haleciidae, Sertulariidae, Plumulariidae and Aglaopheniidae — collected from bathyal environments of the Gulf of Cadiz (22 haplotypes), Greenland (1 haplotype), Azores (1 haplotype), the shallow waters of the UK (17 haplotypes) and Portugal (2 haplotypes). When combined and analysed with 68 additional sequences published in GenBank, corresponding to 63 nominal species of these families (nine species in common between the GenBank sequences and those presented by the authors), cryptic species were detected (e.g. two species of Nemertesia and other of Lafoea ), as well as apparent cases of conspecificity (e.g. Nemertesia antennina and N. perrieri and Aglaophenia octodonta , A. pluma and A. tubiformis ). Other taxonomic inconsistencies were found in the data including cases where species from different genera clustered together (e.g. Sertularia cupressina , Thuiaria thuja , Abietinaria abietina and Ab. filicula ). The mitochondrial 16S rRNA proved to be a useful DNA 'barcode' gene for hydroids, not only allowing discrimination of species, but also in some cases of populations, genera and families, and their intra- or interphylogenetic associations. Although still under-represented in public data bases, the 16S rRNA gene is starting to be used frequently in the study of hydroids. These data provide powerful complementary evidence for advancing our understanding of hydrozoan systematics.     

The distribution of hydroids (Cnidaria, Hydrozoa) from micro- to macro-scale: Spatial patterns on habitat-forming algae

Scaling up from local, short-term experiments to larger-area and longer-term ones is crucial to address the role of scale in ecology. Few studies, however, examined large-scale spatial variability in the distribution and abundance of marine organisms, with rare attempts to directly compare spatial variation at local (centimetres-metres) vs. regional (1000's of kilometres) scale. Here, we used a hierarchical design to describe the spatial distribution of the hydroids epiphitic of the brown alga Cystoseira amentacea, a habitat-forming species that provides a continuous, extensive settling substrate at regional scale along the rocky coasts in the Mediterranean Sea. This continuity provides the potential to deal with scale-related variability, increasing area of investigation without adding differences deriving from habitat heterogeneity or changes in topographic complexity. Hydroids were selected for their abundance and for their life cycle features (rapid growth, small body size, early sexual or asexual reproduction and short life span), allowing rapid responses to changes in environmental conditions. The aim of this study was to analyse whether the structure of hydroid assemblages living on C. amentacea had a consistent pattern of variation among three portions of the algal thallus (i.e., basal, middle, and distal) across a spectrum of scales and whether having or not a pelagic stage could exert a significant influence on the distribution patterns of the species. A total of 32 species were identified. Multivariate analyses showed that hydroid colonization of Cystoseira occurs differently along each thallus, with patterns of variation in the structure of assemblages differing at an even smaller spatial scale than that of single plants. However, such differences varied from patch to patch. Among the 14 species identified as “important” to define the hydroid assemblage inhabiting Cystoseira, only one (Clytia hemisphaerica) has free medusae, the other species reproducing by fixed gonophores or by short-lived medusoids. Univariate analysis showed significant differences among portions of thalli in terms of spatial variability at the various scales investigated, thus suggesting that patterns of multivariate variation along the three portions of thalli might vary across scale. Overall, our results suggest that patterns of distribution of hydroids along C. amentacea thalli significantly vary across spatial scales but that the observed differences can be hardly interpreted on the basis of life-cycle patterns.     

龙胆属的系统发育分析

本文运用支序分类的原理和方法,对龙胆科龙胆属的属下等级进行了重新归类和系统发育分析。龙胆属是一个单系群,以3项近裔共性为归类依据。性状分析作了性状同源性分析和性状极性分析。性状极化主要以外类群比较、性状相关性及染色体资料为依据,其它方法,如生物重演律原则、地理递进原则以及孢粉形态等也被结合使用。分析结果,双蝴蝶属和蔓龙胆属被选择为外类群,71个性状被选择作为建立数据矩阵的基本资料。使用PAUP程序对矩阵进行了运算,得到4个最简约的谱系分支图,它们均具一致性系数0.637,支序长度为160步,f-比值范围为0.179～0.189,其中具最低f-比值的图被选作为类群归类和讨论亲缘关系的基础。在支序图上龙胆属归为15个组;其中5个组又划分为系,共包括23个系,其余组为单型组,故共有33个属下类群。一个严格的一致性谱系分支图总结了所有的一致点,从而支持了支序分析的结果。     

Transmission Genetics of Allorecognition in Hydractinia Symbiolongicarpus (Cnidaria: Hydrozoa)

Allorecognition is ubiquitous, or nearly so, amongst colonial invertebrates. Despite the prominent role that such phenomena have played both in evolutionary theory and in speculations on the origin of the vertebrate immune system, unambiguous data on the transmission genetics of fusibility (i.e., the ability of two individuals to fuse upon tissue contact) is lacking for any metazoan outside of the phylum Chordata. We have developed lines of the hydroid Hydractinia symbiolongicarpus (Phylum Cnidaria) inbred for fusibility and here report results of breeding experiments establishing that fusibility segregates as expected for a single locus with codominantly expressed alleles, with one shared allele producing a fusible phenotype. Surveys of fusibility in field populations and additional breeding experiments indicate the presence of an extensive allele series.     

Benthic hydroids (Cnidaria: Hydrozoa) from the Bransfield Strait area (Antarctica) collected by Brazilian expeditions,with the description of a new species

A total of 36 species of benthic hydroids, belonging to nine families and 16 genera, were found in the hydroid collection gathered during the Brazilian Antarctic expeditions PROANTAR III and IV. Seven of the species were identified only to generic level. There is a clear dominance of the subclass Leptothecatae with 33 species. By far the most diversified family was the Sertulariidae, with 16 species (44%). Symplectoscyphus with eight species, including Symplectoscyphus magnificus sp. nov., is the most diversified genus. Almost 70% of the species diversity is restricted to just six genera (38%). Sixty-eight percent of the species is Antarctic endemics and 86% is restricted to Antarctic or Antarctic/sub-Antarctic waters. Eudendrium antarcticum and Amphisbetia operculata are recorded for the first time from Antarctic waters.     

Nutritional physiology and colony form in Podocoryna carnea (Cnidaria: Hydrozoa)

Abstract. We compared growth rates and final morphological states of the athecate colonial hydroid Podocoryna carnea in two nutritional environments: one varying the quantity of food provided at a fixed interval and the second varying the time between feedings of a fixed quantity. In both environments, replicate colonies were either fed uniformly, or fed on only one side and starved on the other. In addition, we fed colonies fluorescence-labeled cultures of Artemia salina and documented the subsequent distribution of label. We found that both the growth rates and the final morphological state varied logarithmically with food supply. Heterogeneous feeding had a marked effect on colony morphology, with a sharp boundary in polyp number, stolon density, and polyp size forming at the fed–unfed interface. The distribution of fluorescence was correlated with sites of colony growth. These results confirm and extend early work on the priority of growth zones in colonial hydroids, and present new challenges for understanding the relationship among energy metabolism, gastrovascular circulation, and colony form.     

A new superfamily classification of the Caridea (Crustacea: Pleocyemata) based on phylogenetic pattern

Present groupings of Caridea are notoriously unsatisfactory at the superfamily level. Principles of phylogenetic systematics are used to reconstruct 14 monophyletic subgroups of Caridea, based on 19 synaomorphies of adults. The following sequenced phylogenetic classification is provided (main diagnostic character for each superfamily within brackets): 1. Atyoidea (distal lash of Mxp, reduced); Oplophoridae; Atyidae; Pasiphaidae; Agostocarididae; Alvinocarididae; Bresiliidae; Psalidopodidae; Disciadidae; 2. Stylodactyloidea (mandibular palp with 2 segments or absent); Stylodactylidea; Campylonotidae; 3. Eugonatonotoidea (abdominal somite III with dorsal carina bifurcate); Eugonatonotidae; 4. Palaemonoidea (basal segment of antennular peduncle with distolateral tooth); Rhynchocinetidae; Palaemonidae; 5. Nematocarcinoidea (ventral lobe of scaphognathite narrowly triangular); Nematocarcinidae; 6. Pandaloidea (P₁ with chela microscoic or absent); Pandalidae; “Plesionikidae”; Heterocarpidae; Heterocarpoididae; Dorodoteidae; Thalassocarididae; Physetocarididae; 7. Crangonoidea (incisor process of mandible absent); Barbouriidae; Lysmatidae; Merguiidae, fam. n.; Processidae; Glyphocrangonidae; Crangonidae; 8. Alpheoidea (carpus of P₂ with less than 17 segments); Merhippolytidae, fam. n.; Nauticarididae; Alopidae; Bythocarididae; Thoridae; Hippolytidae; Pterocarididae, fam. n.; Ogyrididae; Alpheidae. The monotypic hippolytid taxon Thorellinae, subfam. n., has been formally diagnosed. A survey of the lower Caridea has furnished 276 enera and 2418 species and subspecies. The new superfamily system is simpler, genealogically informative and more precisely diagnosed than previous schemes. These have failed as general reference systems because they were based on the wrong premises that similarities indicate phylogenetic relationships or can be used to construct a single acceptable hierarchy.     

龙胆族(龙胆科)分类与进化研究进展

龙胆是著名的高山植物,广布世界温带地区,不仅可作药用,也可用于园艺观赏。龙胆科分为6个族,其中龙胆族占龙胆科物种数的一半以上;龙胆族包括龙胆亚族和獐牙菜亚族,分类与进化方面的相关研究众多。随着分子生物学在龙胆族研究中的应用,近些年对多个类群进行了研究并发表了多个新属和新种。该文从属间和属内两个层次梳理了龙胆族近年来在分类和进化研究中的最新进展,总结了新发表的类群。并分析了现存的问题,重点强调在今后的研究中用特别注意以下几点:(1)形态性状的准确掌握对龙胆族的研究至关重要;(2)发表新类群应当谨慎;(3)单拷贝核基因有助于解析龙胆族复杂的系统发育关系;(4)关注杂交和多倍化等在龙胆族进化中的作用。     

Mitochondrial phylogenomics reveals insights into taxonomy and evolution of Penaeoidea (Crustacea: Decapoda)

The taxonomy and phylogeny of Penaeoidea have long been fraught with controversy. Here, we carried out the first mitochondrial phylogenomic analysis on all the penaeoid families and tribes, including nine newly sequenced and 14 published mitogenomes, towards elucidating the phylogeny and evolutionary history of Penaeoidea. All these nine mitogenomes exhibit the pancrustacean ground pattern, except that Benthonectes filipes contains two additional clusters of tRNA^Ala, tRNA^Arg and tRNA^Asn and an uncommon noncoding region. The resulted phylogenetic tree is generally well resolved with Benthesicymidae sister to Aristeidae, forming a clade with Solenoceridae. Contrary to traditional classification, this clade has a sister relationship with the tribe Penaeini of the family Penaeidae. The family Sicyoniidae is deeply nested within the penaeid tribe Trachypenaeini which forms a sister clade with the remaining penaeid tribe, Parapenaeini. As the family Penaeidae is recovered to be polyphyletic, the three tribes in Penaeidae are all elevated to familial status. On the other hand, the family Sicyoniidae is retained to accommodate Trachypenaeini because they are now synonyms and the former name is more senior. This work is the first molecular analysis concurring with the latest findings in fossil assessments showing that Parapeaneini is the most primitive in Penaeoidae. Our results also illustrate a shallow‐water origin and an onshore–offshore evolutionary shift in penaeoid shrimps.