MICROFISSURATA GEN. NOV. (BACILLARIOPHYTA), A NEW DIATOM GENUS FROM DYSTROPHIC AND INTERMITTENTLY WET TERRESTRIAL HABITATS1

A new freshwater benthic diatom genus, Microfissurata gen. nov., was identified from light and scanning electron micrographs. The most characteristic morphological feature (referred to also by the name of the new genus) is the structure of the striae/alveoli, which are simple, mostly uninterrupted, transapical slits. The combination of characteristics of the new genus is unique. It includes two new species: Microfissurata paludosa Cantonati et Lange‐Bert. sp. nov. and M. australis Van de Vijver et Lange‐Bert. sp. nov., distributed in Europe and on an austral island, respectively. The new genus occurs in freshwater dystrophic lakes, pools, seepage springs, mires, and in intermittently wet terrestrial habitats. It is not abundant but widespread wherever these habitat types are well developed, in Nordic‐alpine and sub‐Antarctic areas. Overall, the new genus appears to be mostly epiphytic (bryophilous) and capable of tolerating a wide range of moisture conditions (xerotolerant). The finding of the type species (M. paludosa) in a well‐investigated area like central Europe highlights the diatom species richness of dystrophic habitats and their importance for diatom biodiversity conservation.     

Description of Conticribra tricircularis,a new genus and species of Thalassiosirales,with a discussion on its relationship to other continuous cribra species of Thalassiosira Cleve (Bacillariophyta) and its freshwater origin

A new diatom genus Conticribra is erected to accommodate C. tricircularis, described from a freshwater Pliocene deposit in Trout Creek, Oregon (USA). The genus accommodates species possessing: (i) loculate areolae with (semi-) continuous cribra; (ii) non-plicated valve face; (iii) rimoportula located on the valve mantle, replacing a fultoportula. Conticribra tricircularis has no valve face fultoportulae and can easily be distinguished by its marginal fultoportulae with four satellite pores arranged in three rings. Three species are transferred to the new genus from Thalassiosira sensu lato. Using evidence from the fossil record and recent molecular data, a hypothesis concerning the freshwater origin of Conticribra is discussed.     

ACHNANTHIDIUM DOLOMITICUM SP. NOV. (BACILLARIOPHYTA) FROM OLIGOTROPHIC MOUNTAIN SPRINGS AND LAKES FED BY DOLOMITE AQUIFERS1

A new benthic freshwater diatom, Achnanthidium dolomiticum sp. nov., was identified from light and scanning electron micrographs. The most characteristic morphological features are a narrow, but distinctive fascia; a filiform raphe with narrowly spaced central ends and a very narrow and straight axial area on the raphe valve; a convex‐shaped rapheless valve; the length/width ratio; and valve outline. The new species, has been found so far to be mainly epiphytic on bryophytes and aquatic vascular plants in carbonate springs and lakes of the Italian Alps. The environmental preferences of the new species, as assessed by the comparative analysis of these sites, appear to be quite distinctive. These freshwater habitats are fed by drainage basins dominated by dolomite lithology with medium mineralization, are oligotrophic, and are affected by seasonal desiccation.     

Maranta rugosa sp. nov. (Marantaceae) from central Brazil

Maranta is a neotropical genus usually found in moist and shaded habitats in pluvial to semideciduous forests and Cerrado, with diversity center in central Brazil. A new species from Mato Grosso, M. rugosa J. M. A. Braga & S. Vieira, is described and illustrated. The new species is somewhat similar to M. parvifolia Petersen with which it is compared.     

Six New Species of Fresh and Brackish Water Ostracods (Crustacea) from Yakushima, Southern Japan

Twelve species of brackish and freshwater ostracods were collected from the island of Yakushima in southern Japan. Six species, belonging to the genera Cypria, Dolerocypris, Stenocypris, Schellencandona and Paracypria, are new and are described herein. The genus Schellencandona is reported for the first time outside Europe. Although a wide range of apparently suitable habitats was sampled for ostracods across the island, all specimens were recovered from or near the coast; further inland yielded no ostracods. The freshwater habitats around the coast of the island consist of springs and rockpools at the top of the shore above most high tide levels.     

Brevilinea pocosinensis Siver, Hamilton & Morales gen. et sp. nov., a new diatom (Bacillariophyceae) genus from North Carolina, USA

A new diatom genus, Brevilinea gen. nov., is described from an acidic freshwater lake situated on the Atlantic Coastal Plain of North Carolina, USA. The type for the genus, Brevilinea pocosinensis sp. nov., differs from other diatoms by the presence of a unique and reduced raphe that is restricted to the central portion of the valve. The new taxon has large and distinctive areolae that also serve to separate it from existing genera. The taxonomic placement of the new organism relative to other diatoms possessing a reduced raphe is discussed. Although Brevilinea may eventually be placed into a new family, given the current dynamic state of diatom systematics, it is premature to do so at this time.     

Geographic variation in otolith morphology among freshwater populations of Aphanius dispar (Teleostei,Cyprinodontiformes) from the southeastern Arabian Peninsula

Aphanius Nardo is a large genus of teleost fishes in the Old World, with 19 described species. Several of these species have only recently been recognized and additional species can be expected from isolated populations in remote areas. We show here that otolith morphology and statistical analyses of otolith variables can contribute to the detection of genetic differentiation in Aphanius. We studied samples of eight Aphanius dispar populations from the southeastern part of the Arabian Peninsula. Two populations originate from freshwater habitats far inland and probably have been isolated since the late Holocene some 4,000 years ago, three populations come from freshwater habitats with occasional connections to the sea, one population originates from a coastal site, and two were artificially introduced populations. The coastal population is interpreted as possessing the basic otolith type of A. dispar. The basic otolith type also occurs in fishes from the freshwater habitat which is located closest to the coast. Otoliths from the two other freshwater populations with occasional connections to the coast differ slightly from the basic type. However, the two populations from the long‐term isolated freshwater habitats far inland show distinct morphological changes. Our results are consistent with the hypotheses that i) otolith morphology is primarily genetically determined and is little influenced by physical parameters of the habitat, and ii) isolated A. dispar populations may be capable of evolving into new species within short periods of time. J. Morphol., 2009. © 2008 Wiley‐Liss, Inc.     

Kulikovskiyia gen. nov. (Bacillariophyceae) from the lateritic rock pools of the Western Ghats,India and from Hainan Province,China

A new triundulate naviculoid diatom genus is described from the Western Ghats of Peninsular India and Hainan Province, China. The new taxon, Kulikovskiyia gen. nov. has robust conical spines along its margin and at the apices and the external valve face has longitudinally‐oriented siliceous slat system extending the length of the valve. The external distal raphe ends bifurcate and terminates on the valve face. There appear to be superficial similarities between this Asian genus and species and Playaensis, a genus comprised of two species found only in the western USA. The systematic position of Kulikovskiyia is discussed, and other than noting its similarities to other biraphid naviculoid diatoms due to symmetry features and the position of the raphe, we are uncertain about its systematic placement at finer levels of classification.     

Evaluating diatom community composition in the absence of marked limnological gradients in the high Arctic: a surface sediment calibration set from Cornwallis Island (Nunavut,Canada)

Fossil diatom assemblages preserved within the sedimentary record in Arctic lakes provide the potential to reconstruct past changes in important limnological variables. During the summers of 1992 and 1993, we examined previously unstudied freshwater ecosystems on Cornwallis Island, Arctic Canada, with the specific objectives of (1) documenting the limnology and modern diatom assemblages from this region, and (2) determining which environmental variables most influence diatom species distributions. The Cornwallis Island study sites displayed the least amount of variance in measured water chemistry variables in comparison to nearly all of our labs’ previous freshwater surveys in the Arctic. The small limnological gradients precluded the development of a statistically robust diatom inference model, but perhaps more importantly, allowed us to explore variations in diatom composition in the absence of marked variations in water chemistry. Diatom species turnover was minimal, with the most common diatom taxa being Achnanthidium minutissima, Nitzschia perminuta, N. frustulum, with lesser percent abundances of Chaemaepinnularia soehrensis, Navicula chiarae, Psammothidium marginulata, and A. kryophila. A small number of study sites differed from the majority with respect to water chemistry (e.g., coastal sites with high specific conductivities) and habitat availability (e.g., ephemeral ponds with extensive moss habitats), and these sites had markedly different diatom assemblages. These data reinforce previous observations that water chemistry and other climate-related factors are the primary environmental controls influencing diatom distributions at high latitudes. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A polyphasic approach to the study of the genus Nitzschia (Bacillariophyta): three new planktonic species from the Adriatic Sea

The paraphyletic diatom genus Nitzschia comprises over 1000 morphologically distinct pennate taxa, known from the benthos and plankton of freshwater, brackish, and marine environments. The principal diagnostic characters for delimitation of Nitzschia species include valve shape, the position and structure of the raphe, presence/absence and shape of the proximal raphe endings and terminal raphe fissures, areola structure, and specific morphometric features such as cell size, and stria and fibula density. In this study, we isolated 12 diatom strains into culture from samples collected at the surface or greater depths of the southeastern Adriatic Sea. Morphological analyses included LM, SEM, and TEM observations, which, along with specific morphometric features, allowed us to distinguish three new Nitzschia species. These findings were congruent with the results of phylogenetic analyses performed on nuclear‐encoded SSU (18S) rDNA and chloroplast‐encoded rbcL and psbC genes. One of the new species (Nitzschia dalmatica sp. nov.) formed a lineage within a clade of Bacillariaceae containing members of the Nitzschia sect. Dubiae, which was sister to Psammodictyon. A second lineage was part of a novel clade that is significantly distinct from other Nitzschia species sequenced so far and includes Nitzschia adhaerens sp. nov. and N. cf. adhaerens. A further new species was found, Nitzschia inordinata sp. nov., which appeared as the sister group to the N. adhaerens clade and the conopeoid Nitzschia species in our phylogenetic trees. Our findings contribute to the overall diversity of genus Nitzschia, especially in identifying some deep branches within the Bacillariaceae, and highlight under‐scoring of this genus in marine plankton.     

A new genus and species of freshwater monostiliferous hoplonemertean (Nemertea, Enopla) from the People's Republic of China

A new genus and species of freshwater monostiliferous hoplonemertean, Limnemertes poyangensis gen. et sp. nov., from Poyang Lake, People's Republic of China, is described and illustrated. The taxon is compared and contrasted with previously described freshwater hoplonemerteans. This is the fourth species of freshwater nemertean to be described from China and the first recorded from Poyang Lake.     

Pleurosigma hinzianum sp. nov. and P. frenguellianum sp. nov. (Pleurosigmataceae,Bacillariophyta) from Argentinean coastal waters,in comparison with P. amara Stidolph and P. elongatum W. Smith

Two new marine diatom species from Argentinean coastal waters, Pleurosigma hinzianum Sterrenburg, Sunesen & Sar, sp. nov. and P. frenguellianum Sunesen, Sterrenburg & Sar, sp. nov., are described. The characters permitting their identification are specified, based on comparison with type material of the morphologically similar species P. amara Stidolph and P. elongatum W. Smith in the light (LM) and scanning electron microscope (SEM). New information on the type material of P. elongatum is presented and its taxonomic concept is emended. The main criteria for separation of the species discussed here are: valve outline, path of the raphe-sternum, raphe angle and angle of intersection of the oblique striae in LM; and external central and terminal raphe fissures, internal details of the central area, external and internal apical structure, and morphology of the hymen-occluded internal pores in SEM. The occurrence of these (and probably other) species in the genus Pleurosigma in net samples is adventitious and not indicative of a true planktonic mode of life.     

A new surface gliding species of Chironomidae: An independent invasion of marine environments and its evolutionary implications

Insects have invaded marine habitats only rarely and secondarily. Recently, we discovered a flightless dipteran species skating rapidly on the surface of seawater ponds at the Pacific coast of eastern China. Morphological analyses initially suggested an isolated position of the non‐biting midge, suggesting the erection of a new genus within Chironomini (Diptera: Chironomidae). However, an analysis of molecular data revealed that the marine species is in fact nested within the species‐rich genus Dicrotendipes. The apparent conflict between molecular and morphological data can be easily explained. It is likely that the new species has evolved a series of autapomorphic adaptations. These traits clearly distinguish the taxon from other species of the genus but do not justify the erection of a new supraspecific taxon, which would render Dicrotendipes paraphyletic. The switch to marine environments was likely a trigger for various morphological modifications resulting from increased selective pressure. Molecular data suggest that the potential speciation event occurred around 19–29 Ma, linked with a migration from freshwater to seawater ponds along the Pacific Ocean. Considering the results of our analysis, we place the flightless marine skater in the genus Dicrotendipes. All life stages of Dicrotendipes sinicus Qi & Lin sp. n. are described and illustrated, associated with larvae obtained by rearing or confirmed through association with DNA barcodes. The biology and ecology of the species are outlined based on collection data and in situ observations. Evolutionary patterns linked with repeated invasions of marine habitats are discussed.     

A new freshwater heteronemertean from the Zhujiang (Pearl River), People's Republic of China

A new genus and species of freshwater heteronemertean, Amniclineus zhujiangensis, from the Zhujiang (Pearl River), People's Republic of China, is described and illustrated. The species is placed in the family Lineidae along with the existing freshwater heteronemertean taxa, with which its anatomy is compared.     

New freshwater diatom genus,Edtheriotia gen. nov. of the Stephanodiscaceae (Bacillariophyta) from south‐central China

We describe a new genus and species of the diatom family Stephanodiscaceae with light and scanning electron microscopy from Libo Small Hole, Libo County, Guizhou Province, China. Edtheriotia guizhoiana gen. & sp. nov. has striae across the valve face of varying lengths, and are composed of fine striae towards the margin and onto the mantle. Many round to stellate siliceous nodules cover the exterior of the valve. External fultoportulae opening are short tubes; the opening of the rimportula lacks a tube. Internally a hyaline rim is positioned near the margin. Marginal fultoportulae possess two arcuate opercles. Areolae have domed cribra on the valve face. Those near the margin do not open to the interior. One to three sessile to slightly‐raised rimportulae are placed on the valve face towards the margin; they do not terminate shortened striae towards the center of the valve. This suite of features distinguishes this group from other known genera in the Stephanodicaeae. Cyclotella shanxiensis is transferred to Edtheriotia, making the new combination E. shanxiensis (Xie & Qi) Kociolek et al. comb. nov. It differs from E. guizhoiana by the presence of open pores near the margin of the valve. Features of the new genus are compared and contrasted with others in the Family Stephanodiscaceae. The two species of the genus, unlike most in the family, are known only from rivers and ponds from China and Japan.     

First record of the family Thamnocephalidae (Crustacea: Anostraca) from Southeast Asia and description of a new species of Branchinella

During a two-year investigation of freshwater microcrustaceans in Thailand, an undescribed species of fairy shrimp of the genus Branchinella Sayce, 1903 in the family Thamnocephalidae, was discovered. This is the first record of the genus and the family from Southeast Asia and the second anostracan reported from Thailand. The new species, Branchinella thailandensis n. sp. appears to be morphologically intermediate between B. kugenumaensis (Ishikawa, 1895) from Japan and east China, and B. madurai Raj, 1951 from India and Pakistan. B. thailandensis n. sp. was collected from several temporary ponds in 11 provinces of the northeast and the central Thailand, often co-occurring with Streptocephalus sirindhornae Sanoamuang, Murugan, Weekers & Dumont, 2000.     

Two Anaerobic Ciliates (Ciliophora,Armophorea) from China: Morphology and SSU rDNA Sequence,with Report of a New Species,Metopus paravestitus nov. spec

The morphology and phylogeny of two metopid ciliates, collected from anaerobic habitats in China, were investigated using live observation, protargol staining method, and SSU rDNA sequencing. The new species Metopus paravestitus nov. spec. can be distinguished by a combination of the following features: oblong cell with densely arranged ectobiotic prokaryotes perpendicular to cell surface, filiform intracytoplasmic structures packed in the anterior portion of the cell. Our work also demonstrates the wide geographical distribution of Metopus es (Müller, 1776) Lauterborn, 1916. The order Metopida is consistently depicted as a paraphylum in SSU rDNA phylogeny. Metopus paravestitus nov. spec. is closely related to its marine congeners than to freshwater forms. The present study confirms once again the non-monophyly of the genus Metopus and genus Metopidae.     

中国淡水硅藻新记录——偏肿内丝藻兴凯变种

于2016年5月对浙江省仙居国家公园进行藻类多样性调查时,发现了中国淡水硅藻的1个新记录种——偏肿内丝藻兴凯变种[Encyonema ventricosum var.hankensis(Skvortzov) RodionovaPomazkina]。该文采用光镜和扫描电镜对偏肿内丝藻兴凯变种浙江种群的形态特征进行了观察和描述,并将其与该种的其他地理种群及内丝藻属其他相似物种的形态特征进行比较,同时讨论了该物种的生境特征。结果表明:(1)偏肿内丝藻兴凯变种壳面均具明显背腹之分,背缘明显拱起,腹缘轻微波曲;端部呈头状至喙状。(2)偏肿内丝藻兴凯变种浙江地理种群在背部中央区域具一孤点,而其兴凯种群对孤点这一特征未有描述。(3)偏肿内丝藻兴凯变种在俄罗斯的兴凯湖和贝加尔湖等地有分布,该种在中国是首次报道。     

NITZSCHIA ALICAE SP. NOV. AND N. PURIFORMIS SP. NOV., NEW DIATOMS FROM EUROPEAN RIVERS AND COMPARISON WITH THE TYPE MATERIAL OF N. SUBLINEARIS AND N. PURA1

Nitzschia sublinearis Hustedt and N. pura Hustedt are common oligosaprobic freshwater diatom species that frequently occur in diatom inventories, thus being important in water quality studies. Both are considered as species with overlapping diagnostic criteria in several floras, which is typical of the whole genus Nitzschia. The type material of Hustedt of N. sublinearis and N. pura was examined using LM and EM in order to document the range of variation within the type populations and to compare it with populations occurring in different European rivers. Detailed observations allowed recognition of two new freshwater diatom species: N. alicae sp. nov., occurring in mesotrophic up to eutrophic conditions, and N. puriformis sp. nov., mostly occurring in oligotrophic habitats, both in rivers and streams at middle and high altitudes. The most reliable taxonomic features that separate both new species from the most similar taxa are the density of fibulae and striae, valve shape, and valve width as well as the shape of areolae. Morphological examination of different populations indicates that N. puriformis is relatively common in European rivers and has been overlooked to date and confounded with N. pura by several researchers. By contrast, N. alicae has, to date, been collected only in Slovakia and Northern Italy, but with a high frequency of occurrence and sometimes in high abundance at sites.     

Auxosporulation in Chaetoceros acadianus sp. nov. (Bacillariophyceae), a new member of the Section Compressa

We document the fine structure of auxospores in a Chaetoceros species isolated from the Acadian coast of New Brunswick, Canada. Auxospore development in this species occurs in a terminal rather than lateral position, a characteristic never before observed in this genus. Our observations suggest that auxosporulation was uniparental, probably an extreme form of autogamy with sister nuclei fusing following meiosis II. Mature auxospores were adze-shaped to sub-globular and contained both scales and transverse perizonia in their walls. The transverse perizonial band structure was similar to longitudinal perizonial bands found in other species of Chaetoceros and differed from the pinnate bands of pennate transverse perizonia, which consisted of a central rib and bilateral fimbria. Instead, the band structure in C. acadianus was more similar to unilateral fimbriate bands in cymatosiroids. We also propose that our diatom represents a species new to science and is a member of the Chaetoceros Section Compressa. We provide its morphological, molecular and reproductive characterization.