<Emphasis Type="Italic">Stephanthus antarcticus,</Emphasis> a new genus and species of sea anemone (Actiniaria,Haloclavidae) from the South Shetland Islands,Antarctica

Stephanthus antarcticus gen. nov. et sp. nov. is described and illustrated from six specimens collected in the Antarctic Peninsula on the Polarstern cruises ANT XV/3 and ANT XIX/3. The new genus is characterised by the absence of sphincter and basilar musculature, the presence of a single strong siphonoglyph with a basal enlargement, distinct parietobasilar musculature, tentacles without acrospheres, two cycles of six pairs of mesenteries (only one of them perfect), and a deep fosse with parapet; another remarkable feature is the absence of microbasic p-mastigophores. The new genus shows characteristics of three families of soft-bottom-dwelling sea anemones, namely Haloclavidae Verrill, 1899, Halcampoididae Appellöf, 1896, and Andresiidae Stephenson, 1922. The generic characters of Stephanthus gen. nov. are discussed and it is tentatively placed in the family Haloclavidae.     

Growth, reproduction and survival of a tropical sea anemone (Actiniaria): benefits of hosting anemonefish

The ecological performance of the sea anemone Heteractis magnifica was examined during a 36-month experiment with respect to season and the presence and numbers of a mutualist (orange-fin anemonefish Amphiprion chrysopterus). Anemones primarily grew during the autumn, with most asexual reproduction occurring in winter; mortality was not strongly seasonal. Individual growth rates did not differ between anemones harboring one or two anemonefish, but these rates were three times faster than for anemones lacking Amphiprion. Anemones with two anemonefish had the highest fission rate, whereas those without anemonefish had the lowest. By contrast, anemones that were not defended by anemonefish suffered higher-than-expected mortality. As a consequence, anemones with two Amphiprion had the greatest net increase in surface area, and those lacking anemonefish had a negligible gain that was statistically indistinguishable from zero after three years. Anemonefish not only enhanced anemone survivorship as previously believed, they also fostered faster growth and more frequent asexual reproduction.     

2018年夏秋季南设得兰群岛周边水域南极磷虾集群类型及其影响因素

南极磷虾是一种典型的集群性海洋生物,其集群特征为行为生态学研究领域的重要内容之一。南极磷虾在南设得兰群岛周围高度密集分布,然而磷虾集群形状和大小的机制解释仍存在较大的争议。基于南设得兰群岛周边水域收集的Simrad EK80声学数据,本研究利用Echoview V6.16软件,对声学数据进行了分析,并对磷虾集群特征进行了划分。通过主坐标分析(PCoA)检验了环境因素(表温和海况)以及时空因素对各类型磷虾集群产生的影响。结果表明:海况对磷虾集群影响较大,光照强度次之;块状小型集群的时空分布较广,夜间与白天均占有较高比例(>30%);小型集群更易出现在白天,而大型集群则更多出现在深夜; 2月,磷虾集群与海况及纬度显著相关; 3月,集群与时段显著相关; 4月,集群与时段及海况显著相关。     

Interannual variation in the diet of non-breeding male Antarctic fur seals, <Emphasis Type="Italic">Arctocephalus gazella</Emphasis>, at Isla 25 de Mayo/King George Island

The diet of non-breeding male Antarctic fur seals, Arctocephalus gazella, was investigated at Stranger Point, King George Island, through the analysis of scats during three consecutive summer seasons (1996, 1997, 1998). Overall, fish and krill were the most frequent prey occurring, respectively, in an average of 82.9% and 78.8% of samples (n = 131), followed by penguins (22.8%) and cephalopods (17.8%). Myctophids constituted almost 90% of the fish predated, with Electrona antarctica and Gymnoscopelus nicholsi being the most abundant and frequent species consumed. All fish taxa identified were krill feeding species suggesting that seals foraged mainly on a krill and a fish community associated with krill aggregations. However, a seasonal change was observed in the relative proportions of the different prey taxa, with a progressive decrease with time in the occurrence of krill and a concomitant increase of fish, penguins and squid. Possible influence of the strong 1997/98 ENSO event is discussed.     

Desmarestia antarctica (Desmarestiales,Phaeophyceae), a new ligulate Antarctic species with an endophytic gametophyte

Desmarestia antarctica Moe & Silva, a new species from the Antarctic Peninsula and the Scotia Arc, is distinguished from all other ligulate members of the genus by the arrangement of zoosporangia, which are produced together with paraphyses in a raised sorus. Among all species in the genus, onlyD. anceps Montagne shares this feature.Desmarestia antarctica is the first species of the genus for which an endophytic gametophyte is demonstrated, the usual host beingCurdiea racovitzae De Wildeman, a red alga of the familyGracilariaceae. The sporophyte contains only a moderate concentration of acid compared to Northern Hemisphere ligulate species, while physodes that probably contain polyphenolic compounds form noticeable speckles and dark margins in preserved plants. Often more than one axis arises from a single holdfast, probably as the result of compounding rather than proliferation.Dedicated to Prof. DrLothar Geitler on the occasion of the 90th anniversary of his birthday.     

Plutarchia ecuadorensis (Ericaceae,Vaccinieae): a new species and a new generic record for Ecuador

Plutarchia, a shrubby páramo genus, is here reported for the first time in Ecuador where two species are recognized: P. angulata A. C. Smith and the new P. ecuadorensis Luteyn. These two species are keyed, described, and the new species illustrated.     

Population substructure and signals of divergent adaptive selection despite admixture in the sponge Dendrilla antarctica from shallow waters surrounding the Antarctic Peninsula

Antarctic shallow‐water invertebrates are exceptional candidates to study population genetics and evolution, because of their peculiar evolutionary history and adaptation to extreme habitats that expand and retreat with the ice sheets. Among them, sponges are one of the major components, yet population connectivity of none of their many Antarctic species has been studied. To investigate gene flow, local adaptation and resilience to near‐future changes caused by global warming, we sequenced 62 individuals of the sponge Dendrilla antarctica along the Western Antarctic Peninsula (WAP) and the South Shetlands (spanning ~900 km). We obtained information from 577 double digest restriction site‐associated DNA sequencing (ddRADseq)‐derived single nucleotide polymorphism (SNP), using RADseq techniques for the first time with shallow‐water sponges. In contrast to other studies in sponges, our 389 neutral SNPs data set showed high levels of gene flow, with a subtle substructure driven by the circulation system of the studied area. However, the 140 outlier SNPs under positive selection showed signals of population differentiation, separating the central–southern WAP from the Bransfield Strait area, indicating a divergent selection process in the study area despite panmixia. Fourteen of these outliers were annotated, being mostly involved in immune and stress responses. We suggest that the main selective pressure on D. antarctica might be the difference in the planktonic communities present in the central–southern WAP compared to the Bransfield Strait area, ultimately depending on sea‐ice control of phytoplankton blooms. Our study unveils an unexpectedly long‐distance larval dispersal exceptional in Porifera, broadening the use of genome‐wide markers within nonmodel Antarctic organisms.     

Ultrastructural features of the trophonema and oogenesis in the starlet sea anemone, Nematostella vectensis (Edwardsiidae)

Abstract. The starlet sea anemone, Nematostella vectensis Stephenson 1935, is a burrowing, estuarine species that has become a model organism for fundamental studies of cnidarian and metazoan development. During early oogenesis, oocytes appear in the basal region of the gastrodermis in the reproductive mesenteries and gradually bulge into the adjacent connective tissue space (mesoglea) where the majority of oocyte growth and vitellogenesis occurs. However, oocytes do not physically contact the cellular and amorphous matrix of the mesogleal compartment due to a thin, intervening basal lamina. Oocytes retain limited contact with the basal gastrodermal epithelium via groups of ultrastructurally modified gastrodermal cells called trophocytes. Trophocytes are monociliated accessory cells of somatic origin that collectively form a structure called the trophonema, a unique accessory cell/oocyte association not observed outside the Cnidaria. The trophonema consists of 50–60 trophocytes that maintain contact with <1% of the oocyte surface and forms a circular, bowel‐shaped depression on the luminal surface of the gastrodermis as they sink into the mesoglea with the oocyte. The oocyte remains highly polarized throughout oogenesis with the germinal vesicle positioned near the trophonema and presumably representing the future animal pole of the embryo. Contact between the trophonema and the oocyte is restricted to cell junctions connecting peripheral trophocytes and narrow extensions from the oocyte. Previous studies suggest that the trophonema plays a role in transport of extracellular digestive products from the gastrovascular cavity to the oocyte, and the ultrastructural features described in this study are consistent with that view. Vitellogenesis is described for the first time in a sea anemone. Yolk synthesis involves both autosynthetic and heterosynthetic processes including the biosynthetic activity of the Golgi complex and the uptake of extraoocytic yolk precursors via endocytosis, respectively.     

First record of the sea anemone Diadumene lineata (Verrill 1871) associated to Spartina alterniflora roots and stems, in marshes at the Bahia Blanca estuary, Argentina

We report the occurrence of the orange-striped green anemone Diadumene lineata (Verrill 1871) (=Haliplanella lineata) in salt marshes at the Bahía Blanca Estuary for the first time in August 2005. We also found this species attached to roots and stems of Spartina alterniflora, an association that has never been registered before. After their determination, sampling was performed during a year to evaluate seasonal abundance of this sea anemone. Results showed that D. lineata was present through the whole year, indicating the existence of a stable population. All individuals sampled were found attached to roots or stems of S. alterniflora, with the higher abundances detected in summer. Further studies are necessary to precise the potential effects of this exotic sea anemone on salt marsh communities.     

Lycodes nishimurai, a new deep-sea eelpout (Teleostei: Zoarcidae) from the Sea of Japan

A new zoarcid fish, Lycodes nishimuari, is described on the basis of four specimens from the Yamato Bank, the Sea of Japan, at depths of 642–669 m. Although this species resembles Lycodes diapterus, L. hubbsi, L. pectoralis, L. macrochir, and L. nakamurae in having a deep notch in the pectoral fin and a single lateral line on the body, it is distinguished from them by the following combination of characters: no scales on pectoral fin base; scales on dorsum before dorsal fin origin; suborbital, preopercular, and last postorbital pores with risen rim; whitish lips; no whitish transverse bars on body; pectoral fin membrane and anterior part of dorsal fin membrane without black spots; basal color of vertical fins black. Supplementary material to this paper is available in electronic format at .     

Vertical distribution and dietary preferences of deep-sea copepods (Euchaetidae and Aetideidae; Calanoida) in the vicinity of the Antarctic Polar Front

Four Paraeuchaeta species and three aetideids were frequently encountered along 51°30′S in the Atlantic sector of the Southern Ocean. Paraeuchaeta antarctica was most abundant close to the Antarctic Polar Front. Within the genera Paraeuchaeta and Gaetanus, congeners usually partitioned the water column. Euchaetidae had high lipid (≤37% dry mass, DM in adult females) and wax ester contents (≤22% DM). Fatty acid composition of Paraeuchaeta spp. was dominated by monounsaturated moieties, especially 16:1(n-7) and 18:1(n-9), while fatty alcohols were mainly saturated. Surprisingly, only the bathypelagic P. barbata contained moderate amounts of 20:1(n-9) and 22:1(n-11) fatty acids (≤14%) and high levels of the respective fatty alcohols (≤50%), generally considered trophic biomarkers for calanid copepods as prey. Thus, herbivorous calanid copepods seem to be a readily available prey source at bathypelagic depths, indicating that their seasonal vertical migration provides a “trophic shortcut” from primary production at the surface to the interior of the ocean. Aetideidae also contained substantial levels of total lipid (14–36% DM), but wax esters contributed only up to 12% DM in copepodite stages C5 of Gaetanus spp., whereas other stages of Gaetanus and Aetideopsis minor only contained ≤6% DM of wax esters. The fatty acid compositions of Aetideidae were more balanced with 16:0, 18:1(n-9), 20:5(n-3), and 22:6(n-3) as important components, indicating a generally omnivorous feeding behaviour.     

Stygofauna of the Canary Islands, 6 A new Rhipidogammarus (Crustacea,Amphipoda) from Tenerife: first record of the genus outside the Mediterranean region and its biogeographic implications

The discovery of a new species ofRhipidogammarus, Rh. nivariae n. sp., in water supply shafts of Tenerife (Canary Islands), presents an interesting biogeographic problem. Up to now, members of the genus were known exclusively from stygohabitats in the peri-Mediterranean belt. Its sister-genus is found in very shallow waters of the Mediterranean, and on morphological grounds the genus seems to have got adapted only fairly recently to continental hypogean waters. The occurrence of a member ofRhipidogammarus on an oceanic island like Tenerife can be explained by one of the following two scenarios: (1) Tenerife is a fragment of the African plate, or (2) the island's volcanic outcrops arose from a very shallow submarine bank and drifted later into deeper waters.     

The application and citation of the generic nameParmeliopsis (Lecanorales,Parmeliaceae)

The nomenclatural history of the generic nameParmeliopsis is reviewed. Its correct citation is found to beParmeliopsis (Nyl. exStizenb.)Nyl., dating from 1866, not 1869 as commonly cited, withP. placorodia (Ach.)Nyl. as holotype species. There is consequently no nomenclatural problem to the adoption ofForaminella Fricke Meyer, typified byF. ambigua (Wulfen)Fricke Meyer for theParmeliopsis species with falcate conidia. A synopsis of the nomenclature of the North American and European species of both these genera is included.     

The phylogeny of the genus Ischioscia Verhoeff, 1928, with redescriptions of three species (Crustacea: Isopoda: Oniscidea)

The genus Ischioscia Verhoeff, 1928 is reviewed. 26 species are considered valid. A key for their identification is given, as well as a map showing the geographic distribution. The known range of the genus covers a large area from the central Amazon region to the mountains of Guatemala. The species of Ischioscia have a typical “philosciid” habitus (“runner” type); they can be distinguished from other Neotropical species with similar habitus by the following apomorphies: (1) male pereiopod 1 carpus enlarged to a plate-like extension, (2) scale field on male pereiopod 1 covering entire frontal side of the carpus, (3) male pereiopod 7 ischium with a ventral scale field, (4) dactylus in both sexes with a long inner claw. The groundpattern of Ischioscia is reconstructed, and an analysis of the phylogenetic relations within the genus is made on the basis of morphological data. The species are very similar to each other, most differences are found in the male structures of sexually dimorphic features. Ischioscia sturmi (Vandel, 1972), I. amazonica Lemos de Castro, 1955 and I. bolivari Vandel, 1968 are redescribed in detail.     

New species and a new record of Cycas (Cycadaceae) from Thailand

Two newCycas species from Thailand are here described.C. petraea andC. elephantipes. A noteworthy extensions of the range ofC. macrocarpa into southeastern Thailand is recorded. New taxa are illustrated, distributions of the new taxa are mapped, and a key to the species ofCycas in Thailand is provided.     

Characterization of a novel EF-hand homologue, CnidEF, in the sea anemone Anthopleura elegantissima

The superfamily of EF-hand proteins is comprised of a large and diverse group of proteins that contain one or more characteristic EF-hand calcium-binding domains. This study describes and characterizes a novel EF-hand cDNA, CnidEF, from the sea anemone Anthopleura elegantissima (Phylum Cnidaria, Class Anthozoa). CnidEF was found to contain two EF-hand motifs near the C-terminus of the deduced amino acid sequence and two regions near the N-terminus that could represent degenerate EF-hand motifs. CnidEF homologues were also identified from two other sea anemone species. A combination of bioinformatic and molecular phylogenetic analyses was used to compare CnidEF to EF-hand proteins in other organisms. The closest homologues identified from these analyses were a luciferin binding protein (LBP) involved in the bioluminescence of the anthozoan Renilla reniformis, and a sarcoplasmic calcium-binding protein (SARC) involved in fluorescence of the annelid worm Nereis diversicolor. Predicted structure and folding analysis revealed a close association with bioluminescent aequorin (AEQ) proteins from the hydrozoan cnidarian Aequorea aequorea. Neighbor-joining analyses grouped CnidEF within the SARC lineage along with AEQ and other cnidarian bioluminescent proteins rather than in the lineage containing calmodulin (CAM) and troponin-C (TNC).