The distribution and habitat preference of ostracods (Crustacea: Ostracoda) in a coastal sand-dune lake, Loch of Strathbeg, north-east Scotland

SUMMARY. 1. Ostracods were a numerically abundant component of the benthos >0.1 mm in size (up to 20% of the total) in the Loch of Strathbeg.
2. Distinct assemblages of species were associated with some habitats: Cypridopsis vidua (Müller) and Herpetocypris reptans (Baird) with Eleocharis palustris (L.) beds; Cypria uphtalmica (Jurine), Candona Candida Müller and Cypria exsculpta (Fischer) with Phragmites communis Trin. beds; and Limnocythere inopinata (Baird) with open sand. In contrast, no distinct ostracod assemblage was associated with submerged beds of Chara aspera Detharding, or Myriophyllum spicatum (L.).
3. The number of ostracod species and ostracod diversity increased from open sand through macroalgal and submerged macrophytes to emergent macrophyte habitats and was associated with increasing number of types of detritus.
4. Laboratory experiments suggested that substratum particle size played a dominant role in determining the distribution of L. inopinata. This species preferred sandy sediments. The distributions of both H. reptans and C. vidua were affected by food supply and H. reptans also preferred fine-grained sediments. The absence of these taxa from some habitats where food supply and sediment particle size conditions were suitable suggested that unmeasured factors played a role. A possible predatory exclusion of H. reptans from such habitats was indicated by a negative association of this species with a predatory mite.     

A revision of the genus Paradoxostoma Fischer (Crustacea; Ostracoda) in British waters

Species of the genus Paradoxostoma Fischer are an important component of marine and estuarine ostracod faunas throughout the world. This revision of the genus in British waters deals with 17 species of which six are described as new. Each species is diagnosed and illustrated in detail, and comments are made on their ecology and distribution. The specialized mouthparts which characterize the genus are illustrated by means of the scanning electron microscope for the first time. A key to the genus is given.     

Not an ancient relic: the endemic Livistona palms of arid central Australia could have been introduced by humans

Livistona mariae is an endemic palm localized in arid central Australia. This species is separated by about 1000 km from its congener L. rigida, which grows distantly in the Roper River and Nicholson-Gregory River catchments in northern Australia. Such an isolated distribution of L. mariae has been assumed to have resulted from contraction of ancestral populations as Australia aridified from the Mid-Miocene (ca 15 Ma). To test this hypothesis at the population level, we examined the genetic relationships among 14 populations of L. mariae and L. rigida using eight nuclear microsatellite loci. Our population tree and Bayesian clustering revealed that these populations comprised two genetically distinct groups that did not correspond to the current classification at species rank, and L. mariae showed closest affinity with L. rigida from Roper River. Furthermore, coalescent divergence-time estimations suggested that the disjunction between the northern populations (within L. rigida) could have originated by intermittent colonization along an ancient river that has been drowned repeatedly by marine transgression. During that time, L. mariae populations could have been established by opportunistic immigrants from Roper River about 15 000 years ago, concurrently with the settlement of indigenous Australians in central Australia, who are thus plausible vectors. Thus, our results rule out the ancient relic hypothesis for the origin of L. mariae.     

Ankistromeces mariae n. g., n. sp. (Digenea: Sanguinicolidae) from Meuschenia freycineti (Monacanthidae) off Tasmania

Ankistromeces mariae n. g., n. sp. is described from Meuschenia freycineti (Monacanthidae), the six-spined leatherjacket, from off northern Tasmania. The new genus differs from the 21 other sanguinicolid genera in the combination of the anteriorly intercaecal and posteriorly post-caecal single testis, the presence of a cirrus-sac, the absence of an auxiliary external seminal vesicle, separate genital pores, the typically post-ovarian uterus and the H-shaped intestine. A. mariae is the first sanguinicolid to be reported from a monacanthid fish.     

Taxonomic revision of Rhododendron mariae (Ericaceae) and related taxa

Based on a literature survey and a field trip with specimen examination, statistical analysis including principal components analysis (PCA) on morphological characters have been carried out on Rhododendron mariae and related taxa. Cluster analysis and PCA showed three independent groups, which corresponded to three species except R. loniceriflorum . As a consequence, nine taxa are reduced to synonyms of R. mariae , and two new combinations, viz R. mariae subsp. microphyton , and R. mariae subsp. flumineum are made. Rhododendron microphyton var. trichanthum is reduced to a synonym of R. mariae subsp. microphyton , and R. malipoense to a synonym of R. mariae subsp. flumineum . Three names are synonymized and a new combination, viz R. chryocalyx subsp. meridionale , is proposed within R. chryocalyx . The third entity, R. naamkwanense , has got two new synonyms. Rhododendron loniceriflorum , with whitish pubescence on the inner corolla surface, is recognized as the fourth distinct species. Each entity is illustrated with line drawings for identification.     

A revision of Sabella, Bispira and Stylomma (Polychaeta: Sabellidae)

Sabella is rediagnosed to include only species that have spiralled fascicles of abdominal chaetae, first thoracic shield with straight anterior border and radioles that lack composite eyes and flanges. Spirographis spallanzanii is synonymous with Sabella penicillus . The type of the genus is discussed and a neotype designated. The only other species retained in Sabella are S. pavonina and S. discifera ( = Branchiomma linaresi , once misplaced in Megalomma , but abdominal fascicles of Megalomma form transverse rows). Most species formerly placed in Sabella are transferred to Bispira , having C-shaped fascicles of abdominal chaetae, first thoracic shield with a 'W-shaped anterior border and, in most species, radioles with paired composite eyes and flanges. Bispira , with B. volutacornis as the type species, is rediagnosed to include B. crassicomis, B. fabricii, B. melanostigma, B. tricyclia, B. viola, B. manicata, B. poricfera, B, mariae, B. elegans, B. brunnea, B. guinensis, B. secusolutus, B. wireni, B. oatesiana, B. spirobranchia, B. pacifica, B. monroi , and B. turneri , many of which are described fully for the first time. Only five of these form bispiral crowns (bispirality is useful only specifically and occurs in other genera) and one, B. tricyclia , has a unispiral crown. Sabella palmata Quatrefages, the type of Stylomma is redescribed and its synonyms discussed. This genus has abdominal fascicles like those of Bispira , but radiolar eyes like those of Megalomma . The relative advantages of chaetal arrangement and eye position are discussed.     

广厉螨属1新种和江西伪寄螨补充描述（蜱螨亚纲：中气门目：厉螨科）

描述广厉螨属1新种：宽腹广厉螨Cosmolaelaps robustoventralis sp．nov．，并对江西伪寄螨Pseudoparasitus jiangxiensis Ma，2007进行补充描述。     

Radiation,diversity and environmental expansion of Early Ordovician ostracods: a view from the Southern Hemisphere

Tremadocian–Floian siliciclastic successions in the Argentine Cordillera Oriental are of great interest for the study of early ostracod radiation. Four genera and five species of ostracods have so far been documented in the basin from the Early–Late Tremadocian (Tr2). This contrasts with occurrences from other palaeocontinental areas, where typically only one species is described. Patterns of environmental distribution and ecological approaches of ostracod assemblages were analysed on the basis of richness, Fisher's alpha diversity, relative abundance and occupancy. Ecological patterns remained stable throughout the studied interval, mostly with one genus notably dominant over the others. At the regional scale, dominant taxa occur at a relatively large number of sites, which display high occupancy. The literature data on carbonate successions from the Baltoscandian basin show a similar pattern, with a single taxon dominant over the others in local assemblages and wide regional distribution of these dominants. This ecological pattern would therefore have persisted at least until the Dapingian, independently of the sedimentary regime. Ostracods were already present along the onshore–offshore gradient during the initial stages of radiation, showing a strong preference for deep subtidal settings during Tr2 and then spreading to shallower environments in Tr3 and to deeper ones in the Floian (Fl2–Fl3). A compilation of ostracod diversity data from several regions shows a remarkable increase during the Darriwilian. Based on the regions studied herein, this rise in diversity is decoupled from the environmental expansion of ostracods, as they were already recorded along the onshore–offshore profile early in their history on both siliciclastic and carbonate shelves. The Argentine Cordillera Oriental could be considered as a cradle of diversity, with an important role in the subsequent radiation of the group.     

Extinction pattern of marine Ostracoda across the Pliensbachian-Toarcian boundary in the Cordillera Ibérica, NE Spain: Causes and consequences

This paper discusses the extinction pattern of the Pliensbachian-Toarcian boundary (PTB) ostracod assemblages at the Almonacid de la Cuba section (Cordillera Ibérica, NE Spain), which has been recently proposed as auxiliary boundary stratotype for the PTB. The ostracod record shows that the main Early Jurassic ostracod extinction event occurred not at the end of the Pliensbachian, but near the top of the Mirabile ammonite Subzone, Tenuicostatum ammonite Zone (Early Toarcian). On the basis of the evaluation of PTB ostracod record, a new causal explanation for the Early Toarcian ostracod turnover is proposed. This paper suggests that a reorganization of surface and deep-water circulations caused by the opening of the Hispanic Corridor could have generated a mild cooling episode, finally affecting the survival of healdioid ostracods.     

猝死中美貘死亡原因分析

中美貘(Tapirus bairdii)又名拜氏貘,隶属于奇蹄目貘科貘属,已被世界自然保护联盟列为濒危动物,现主要分布在墨西哥南部至哥伦比亚和厄瓜多尔的安第斯山以西地区。栖息在茂密的热带雨林中,通常单独或成对活动。白天在林中休息,夜间     

Studies on a natural population of Cyclestheria hislopi (Baird) (Conchostraca: crustacea)

The present paper adds further notes on the biology of Cyclestheria hislopi (Baird). An attempt has been made to study the variation in the natural population of this species based on its birth-rate. C. hislopi has dist inct preference for the plant Hydrilla verticellata (Royle) on which they remain attached. It is considered completely parthenogenic, having no males. The period from October to January can be considered to be the growth period for this species, after which the population declines. This decline has been found to be due to the low birth-rate exhibited during the subsequent months.     

Freshwater ostracod assemblages and their relationship to environmental variables in waters from northeast Germany

An ecological calibration dataset for freshwater ostracods from 33 localities throughout West-Pomerania (Mecklenburg-Vorpommern, Germany) was evaluated using multivariate statistical methods. A total of 47 freshwater ostracod species were identified. Nine species were rediscovered after 100 years since the last published record and Candonopsis scourfieldi and Pseudocandona sucki was recorded for the first time in the study area. Special emphasis is put on the phenology of each species to gain information on the water characteristics at the time of their last moult. Canonical correspondence analysis (CCA) revealed that the ecological variables such as water temperature, Ca, Mg, and lake area were statistically most significant (p < 0.005; n = 72) in explaining variation in the distribution of ostracod assemblages. In addition, a transfer function was developed for paleolimnological approaches, based on a weighted-averaging (WA) model to calculate water temperature from the relative abundances of 22 selected ostracod species. This model was successfully applied to infer lake water temperature from subfossil ostracod assemblages collected from lacustrine deposits in northeast Germany (Lake Krakower See). Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.     

Recent benthonic ostracod assemblages as indicators of the Tsushima warm current in the southwestern sea of Japan

One hundred and sixty-seven species of podocopid ostracods are reported from 26 recent surface sediment samples collected on the shelf of the Tsushima Strait in the southwestern Sea of Japan. Four biofacies (A–D) are recognised based on Q-mode cluster analysis. Among these, biofacies B is distributed along the Tsushima Warm Current and includes typical East China Sea species. This fact suggests that the migration of the shelf-living ostracods between the open sea and the adjacent semi-enclosed marginal sea mainly occurs in association with the inflow of this sea current. The distribution of the recent ostracod assemblages from the Tsushima Strait are expected to be a sensitive indicator of past and future changes in the Tsushima Warm Current. One new ostracod species of the family Trachyleberididae, Trachyleberis ikeyai, is described and illustrated herein. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Handling editor: K. Martens     

Pollen studies in subtribe Centaureinae (Asteraceae): the Jacea group analysed with electron microscopy

Although it has been recognized for many years that the genus Centaurea L. is an artificial assemblage of taxa, its partition into more natural affiliations has been impossible due to its incredible complexity. One of the most reliable characteristics for establishing the phylogeny within this group is the type of pollen. Most of the classification difficulties centre in the Jacea group, which has a characteristic Jacea pollen type. Recent molecular studies indicate that this assemblage is probably polyphyletic. Specifically, previous DNA sequence analyses indicate that Centaurea pulchella and the genera Oligochaeta and Zoegea represent different lineages. This finding prompted an investigation of their pollen types, using scanning electron microscopy, and for some species, transmission microscopy. For a rigorous comparison, the study also included a wide representation of other species across the entire Jacea group. Results showed that both Oligochaeta and Zoegea , but not C. pulchella , can be clearly distinguished from the Jacea group on the basis of pollen morphology. The genus Oligochaeta has a peculiar pollen type that may represent a simplified form of the Serratula pollen type, and the genus Zoegea has Serratula pollen type.     

Physiological response of symbiotic polychaetes to host saponins

Two species of the genus Arctonoe occur as host-isolated populations in the tidal and subtidal areas of Puget Sound. A saponin has been isolated from Evasterias troschelii (Stimpson) which has deleterious physiological effects on Arctonoe pulchra (Johnson), a species not associated with the asteroid. This same substance has no adverse effect on the viability and only a slight positive effect on the respiration of Arctonoe fragilis (Baird), the normal companion of Evasterias. These results suggest a possible mechanism for the strict isolation of these polychaetes and provide additional evidence for the biological significance of asterosaponins.     

Effect of the photoperiod of the site of oviposition of Aedes mariae (Diptera,Culicidae)]

The overwintering biology of Aedes (Ochlerotatus) mariae (one of the sibling species of the mariae complex) was studied in populations from the Tyrrhenian coast of Central Italy (Sperlonga and Formia). Ae. mariae has in this zone several generations per year and its larvae are commonly found from March to October exclusively in rock pools along the coast. Field and laboratory observations show in these populations an embryonic winter diapause induced by short-day photoperiods (9-12 hours). The photoperiod acts primarily on the parental females during their preimaginal life. The expression of diapause is influenced by temperatures and photoperiods experienced by the embryos. Full embryonic diapause is observed when the eggs are incubated at relatively low temperatures (less than 16 degrees C) and at short photoperiods. Short-day photoperiods also induce a remarkable change in the oviposition behavior of Ae. mariae. Laboratory observations show that the adult females readily oviposit on water surfaces when originating from larvae reared at long-day photoperiod while they are very reclutant to oviposit in the same situation when reared at short day photoperiod. Choice experiments involving four alternative oviposition sites (see Plate 1) demonstrate a preference for outside free water in long-day mosquitoes and for inside moist surfaces in short-day mosquitoes. The behavioral difference persists in successive gonotrophic cycles and it is not apparently affected by the photoperiod acting on the adult females. The above evidence together with recovery of overwintering eggs in holes and crevices of rock pools suggest that the shift in oviposition site shown in the laboratory reflects a similar shift occurring in nature. Such photoperiodically induced change in oviposition behavior seems to have an important adaptive significance in providing more constant microclimates to the diapausing eggs and in protecting them from the mechanical action of winter storms.