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1.
Summary 10 species of Mysidacea were sampled during the Polarstern and Walther Herwig SIBEX cruises to the Antarctic Peninsula region from 1983 to 1986. The commonest were Antarctomysis maxima, A. ohlini and Mysidetes posthon. For these species the size and maturity stage composition as well as the length-weight relationships are given. The species considered are growing slowly and attain a long life span, M. posthon reached age class 3+, A. ohlini at least lived as long as 5 years, while A. maxima was found to be of age 5+ in the Peninsula area and probably 6+ in the Weddell Sea. The generation time of Antarctomysis species was 4 years and 3 years in Mysidetes posthon. Fecundity was low, mean number of offspring was about 13 for M. posthon and 21 for A. maxima. Rematuration was observed for the species A. maxima, indicating several spawning events during its life span. Biomass production is low for A. maxima, shown by a P/B-index of 0.98. Mortality of this species was estimated to be Z=1.1, which indicates that 33% of the specimens of an age group survive until the next year. The distribution and spatial separation of the two Antarctomysis species is discussed. 相似文献
2.
Argostemma bachmaense, a new species from central Vietnam, is described and illustrated here. The new species is most similar to A. laoticum and A. vietnamicum but can be distinguished from the latter two by having a well-developed internode with leaf pairs separately arranged along stem, isophyllous or slightly anisophyllous leaves, an oblanceolate to spatulate lamina with attenuate base and lateral veins with 4–5 pairs prominent on abaxially, a terminal, solitary flower, an absent bract, narrowly ovate or broadly lanceolate, 8.5–10.5 × 2.8–4.2 mm petals, 6.5–7.5 mm long stamen with yellow anther, a 8.5–9.5 mm long, exerted style and a globose stigma. Information on ecology, phenology and preliminary conservation assessment of the proposed new species are provided. In addition, we also provide an identification key to the nine Argostemma species found in Vietnam. 相似文献
3.
Summary Traits which differ among species in a genus are considered to be the product of relatively rapid evolution. Laboratory studies indicate that copulation differs between two species of the banana slug Ariolimax with A. dolichophallus having a pattern of a single, long duration (typically greater than 1 h) intromission which is simultaneously reciprocal, and A. californicus having mating encounters typically involving a bout of brief (typically 10–20 min) unilateral intromissions. Reciprocal apophallation was observed for both species. Field observations confirm simultaneously reciprocal copulation and apophallation in A. dolichophallus. Mating was more frequent in the spring and summer months. In laboratory studies the two species also differed in life history parameters; mean growth rate was greater in A. californicus than A. dolichophallus, whereas eggs are larger in A. dolichophallus (range = 0.33–0.5 g; n=59) than in A. californicus (range= 0.08–0.27 g; n=164). 相似文献
5.
报道生于豆科植物沙冬青 Ammopiptanthus mongolicus上的链格孢属真菌一新种,沙冬青链格孢 Alternaria ammopiptanthi。此种不同于已从豆科植物上报道的5个长喙链格孢种(复喙链格孢 A. multirostrata、决明链格孢 A. cassiae、猪屎豆生链格孢 A. crotalariicola、瓜尔豆链格孢 A. cyamopsidis和长喙链格孢 A. longirostrata),主要是其分生孢子的长喙不分枝和孢身细瘦。研究过的模式标本(PSNXAAFS 267852)保存在宁夏农林科学院植物病害标本室。 相似文献
6.
报道生于豆科植物沙冬青Ammopiptanthus mongolicus上的链格孢属真菌一新种,沙冬青链格孢Alternaria ammopiptanthi。此种不同于已从豆科植物上报道的5个长喙链格孢种(复喙链格孢A.multirostrata、决明链格孢A.cassiae、猪屎豆生链格孢A.crotalariicola、瓜尔豆链格孢A.cyamopsidis和长喙链格孢A.longirostrata),主要是其分生孢子的长喙不分枝和孢身细瘦。研究过的模式标本(PSNXAAFS267852)保存在宁夏农林科学院植物病害标本室。 相似文献
7.
This paper reviews the pulchra species group of Archips, describes a new species, Archips stellata, and redescribes A. pulchra (Butler) and A. abiephaga (Yasuda). Although long confused with each other, these three species are distinguishable by differences in the wing markings, abdominal dorsal pits, and genitalia. To position the pulchra group systematically within the genus Archips, earlier related studies are reviewed and the phylogenetic relevance and polarities of traits are discussed. The forewing pattern, consisting of transverse black and glossy gray fasciae, is presumed to be the only synapomorphy of this group; affinity between the pulchra group and other groups of Archips in some traits may reflect symplesiomorphy. 相似文献
8.
A new species from evergreen montane forests of Thailand, Hoya somadeeae Rodda & Simonsson is here described and illustrated. The new species may be superficially confused with the Peninsular Malaysia endemic H. wrayi King & Gamble, but is clearly separated from it by the very elongated peduncles, up to 20 cm long, the revolute corollas, and outer processes of corona lobes with a membranaceous basal appendage. Morphological affinities between the new species and other Hoya species from Thailand and neighbouring Myanmar and Peninsular Malaysia are discussed. 相似文献
9.
The freshwater eels of the genus AnguillaSchrank are widely distributed. They have beenconsidered for a long time to all have acatadromous spawning strategy. However, in arecent work Tsukamoto et al. (2002)considered that catadromy should be seen asfacultative. They all have a long oceaniclarval stage known as the leptophalus stage. Alarge number of studies on their ecology,biology, and physiology exist but littleattention has been focused on their systematicsand species-relationships. Ege (1939)described 19 species and sub-species based onmorphometric data. Castle and Williamson (1974)made A. ancestralis a synonym of A.celebesensis. Morphological characters,however, have limitations as taxonomiccharacters because they overlapped in mostspecies. Biochemical characters, such asmt-DNA, are more informative. Dijkstra andJellyman (1999) found no genetic differencesbetween A. australis australis and A. a. schmidtti, and now 15 species arewidely recognized. Phylogenetic studies(Aoyama and Tsukamoto, 1997) suggestdescendant-ancestor relationships betweenAtlantic and Pacific eels, respectively. Themost likely dispersal route for the Atlanticeels from the Pacific appears to have beenthrough the Tethys Sea. Two species are foundin the Atlantic: A. anguilla and A.rostrata. They both spawn in the Sargasso Sea,but differ in morphometric and genetic traits,and are considered as two separate species witha relatively recent evolutionary divergence.The purpose of this paper is to presentknowledge and questions about the life history,taxonomy, and evolution of this mysteriousgenus. 相似文献
11.
Forests respond to increasing intensities and frequencies of drought by reducing growth and with higher tree mortality rates. Little is known, however, about the long‐term consequences of generally drier conditions and more frequent extreme droughts. A Holm oak forest was exposed to experimental rainfall manipulation for 13 years to study the effect of increasing drought on growth and mortality of the dominant species Quercus ilex, Phillyrea latifolia, and Arbutus unedo. The drought treatment reduced stem growth of A. unedo (?66.5%) and Q. ilex (?17.5%), whereas P. latifolia remained unaffected. Higher stem mortality rates were noticeable in Q. ilex (+42.3%), but not in the other two species. Stem growth was a function of the drought index of early spring in the three species. Stem mortality rates depended on the drought index of winter and spring for Q. ilex and in spring and summer for P. latifolia, but showed no relation to climate in A. unedo. Following a long and intense drought (2005–2006), stem growth of Q. ilex and P. latifolia increased, whereas it decreased in A. unedo. Q. ilex also enhanced its survival after this period. Furthermore, the effect of drought treatment on stem growth in Q. ilex and A. unedo was attenuated as the study progressed. These results highlight the different vulnerabilities of Mediterranean species to more frequent and intense droughts, which may lead to partial species substitution and changes in forest structure and thus in carbon uptake. The response to drought, however, changed over time. Decreased intra‐ and interspecific competition after extreme events with high mortality, together with probable morphological and physiological acclimation to drought during the study period, may, at least in the short term, buffer forests against drier conditions. The long‐term effects of drought consequently deserve more attention, because the ecosystemic responses are unlikely to be stable over time.Nontechnical summaryIn this study, we evaluate the effect of long‐term (13 years) experimental drought on growth and mortality rates of three forest Mediterranean species, and their response to the different intensities and durations of natural drought. We provide evidence for species‐specific responses to drought, what may eventually lead to a partial community shift favoring the more drought‐resistant species. However, we also report a dampening of the treatment effect on the two drought‐sensitive species, which may indicate a potential adaptation to drier conditions at the ecosystem or population level. These results are thus relevant to account for the stabilizing processes that would alter the initial response of ecosystem to drought through changes in plant physiology, morphology, and demography compensation. 相似文献
12.
A multivariate analysis has been performed in order to study the polymorphisms of the three species of Potentilla sect. Recta ( Th. Wolf) Juzepchuk represented in the Iberian Peninsula: P. asturica
Rothm., P. hirta L. and P. recta L. The variability of 20 characters (quantitative, binary and qualitative) has been evaluated in 76 collections mostly from
the Iberian Peninsula and from other European territories, but also from North America, and North Africa. The analyses performed
provide support for the recognition of the three species. The most discriminant among the quantitative characters is the width
of the long trichomes on the stem, and then the width of the long trichomes on the leaves and the maximum length of the long
trichomes. The interval of number of carpels, presence or absence of short eglandular trichomes and the abundance of long
eglandular trichomes (>3 mm) are the most discriminant ones among the qualitative ones. The taxonomical position of P. asturica, which has been previously subordinated as a subspecies within the other two taxa, is discussed. Our results support a good
delimitation of this taxon which, on the basis of the morphological characters studied by us, seems to be morphologically
more close to P. hirta than to P. recta, but differs significantly from both. A key to the three species is provided. 相似文献
13.
Karyotype analyses were conducted on Cunninghamia konishii, Cunninghamia lanceolata, and Taiwania cryptomerioides, all members of Taxodiaceae. The somatic chromosome number was found to be 2n = 2x = 22 in all species which concurrs with previous reports. The karyotypes are generally asymmetrical with the smaller chromosomes being more submedian than the larger ones. Chromosomes with unusual or specific structures, thought to be associated with the nucleolar organizing region, were found in each species. Cunninghamia species have a marker chromosome pair with an unusually long secondary constriction. Taiwania has an unusually long kinetochore region present in a submedian chromosome pair. 相似文献
14.
A new species of Crenosoma Molin, 1861 is described from the lungs of the Eurasian lynx, Lynx lynx (L.) (Carnivora: Felidae). Crenosoma vismani n. sp. differs from other species of the genus in the morphology of the male copulatory organs (two ventral rays originating from a common stem; three lateral rays with common stem; gubernaculum 79–92 μm long, well developed, spoon-shaped; spicules 232–253 μm long, slightly curved, with robust dorsal appendage) and a vulva with rounded, prominent vulvar cuticular appendage is located in middle region of body in females. An analysis of the morphology and life-cycle data for Crenosoma petrowi Morozov, 1939 from Ursus americanus Pallas indicate that this nematode should be described as a new species. The validity of Crenosoma schulzi Gagarin, 1958 is resurrected. A new identification key for the species of Crenosoma is provided. Published records of the genus Crenosoma from definitive hosts and patterns of host specificity are presented. Morphological data revealed that the genus Crenosoma should contain 15 species (14 with valid names) with different host specificity, ranging from oioxenous to euryxenous. However, a review of the current genetic data indicates that the actual number of Crenosoma spp. is greater, and the host range is still unknown, even in Europe. 相似文献
15.
The family Megalyridae is recorded from Japan for the first time on the basis of two new species, Carminator helios and C. japonicus. This is the northernmost record of living Megalyridae, although fossil species are known from regions of the Baltic Sea. Carminator helios can be distinguished from congeners of the Asian and Australian regions by the combination of a long head, deeply excavated frons with convex inner margins, entirely striated postgena, the number of fore tibial spines (more than 16), and a long R 1 vein. Carminator japonicus is distinguishable from other species by the combination of an orange‐colored metasoma, a weakly excavated frons, and an elongate vertex. This species was collected from the canopy of Acer pictum. Additional characters that distinguish species of the genus Carminator are discussed. 相似文献
16.
Intra‐ and interspecific molecular variation were investigated in four members of the Minimus Group of Anopheles subgenus Cellia: An. aconitus, An. varuna, An. minimus A and An. minimus C. DNA sequence divergence between these species at a mitochondrial locus (cytochrome oxidase II) and at three nuclear loci (ITS2 and D3 regions of rDNA and guanylate cyclase) is reported. The data confirm the presence of two cryptic species, A and C, within An. minimus and provide evidence for the existence of a third species. Anopheles minimus A and C are estimated to have diverged 0.57–1.5 million years ago. The discrepancy observed using the guanylate cyclase intron, which is the fastest evolving region known in the Gambiae Complex but is relatively slowly evolving in the Minimus Group, is discussed. The long‐term effective population sizes of An. minimus A and C are estimated to be in their millions, with that of species A being approximately twice the size of species C. This implies that An. minimus C has a much wider distribution than currently recognized, with possible widespread implications for vector control. No evidence was found for population structuring in either species A or C: there was greater variation of mitochondrial haplotypes within than among localities. The phylogenetic relationships of Oriental members of the Myzomyia Series are reconstructed. 相似文献
17.
Neoscombrops annectens Gilchrist, 1922, described from off Natal, South Africa, has long been regarded as a valid species. Although Acropoma cynodon Regan, 1921, also described from off Natal, was found to be Neoscombrops, they were regarded as distinct species, distinguishable by body depth and body color. Examination of many specimens, including the holotype of A. cynodon and neotype of N. annectens, revealed that the differences are within the range of intraspecific variation. N. cynodon is redescribed as a senior synonym of N. annectens. 相似文献
18.
Amphidinium operculatum Claparède et Lachmann, the type species of the dinoflagellate genus Amphidinium, has long had an uncertain identity. It has been considered to be either difficult to distinguish from other similar species or a morphologically variable species itself. This has led to the hypothesis that A. operculatum represents a “species complex.” Recently, the problem of distinguishing A. operculatum from similar species has become particularly acute, because several morphologically similar species have been found to produce bioactive compounds of potential interest to the pharmaceutical industry. In this study, we cultured and examined existing cultures of several species of Amphidinium, most of which have been previously identified as A. operculatum or as species considered by some to be synonyms or varieties of A. operculatum. Thirty strains were examined using comparative LM, SEM, and partial large subunit (LSU) rDNA sequence data. Through morphological and molecular phylogenetic analyses, six distinct species were identified, including Amphidinium trulla sp. nov. and Amphidinium gibbosum comb. nov. Amphidinium operculatum was redescribed based on four cultures. Genetic variability within the examined Amphidinium species varied greatly. There was little difference among strains in partial LSU rDNA for most species, but strains of A. carterae and A. massartii Biencheler differed by as much as 4%. In both A. carterae and A. massartii, three distinct genotypes based on partial LSU rDNA were found, but no morphological differences among strains could be observed using LM or SEM. In the case of A. carterae, no biogeographically related molecular differences were found. 相似文献
19.
This first study of the whole genus Agathis makes use of recent local revisions of the New Caledonian and Australian species which are all maintained. The male cone is shown to have most of the taxonomically useful variation, and this confirms the findings of two partial revisions centred on Indonesian species. Thirteen species are recognized, two of which have two subspecies. New Caledonia has five, and Australia three, sympatric species. Otherwise the species are allopatric except for a few populations of central Malesian A. dammara within the range of west Malesian A. borneensis. One of these montane populations is the distinctive A. dammara subsp. flavescens of Malaya, formerly a full species.Two groups and three individually distinctive species can be recognized on microsporophyll characters. The larger, group B, comprizes eight species, A. australis (New Zealand), A. corbassonii, A. lanceolata and A. montana (New Caledonia), A. macrophylla (Melanesian islands and including A. obtusa and A. vitiensis), A. atropurpurea (Australia), A. dammara (mainly central Malesia) and A. borneensis (west Malesia); both the last have long synonymies. The smaller species, group (A), comprizes A. microstachya (Australia) and A. labillardieri (west New Guinea and the Sepik basin). The individually distinctive species are A. moorei and A. ovata of New Caledonia and A. robusta of Australia with its new subspecies nesophila, described here, of eastern New Guinea and New Britain. 相似文献
20.
记述采自中国西藏的钩瓣叶蜂属 Macrophya Dahlbom 1新种:尖盾钩瓣叶蜂Macrophya acutiscutellaris Wei, Li & Heng sp. nov.。简要讨论了M. planata 种团的特征,编制了M. planata 种团已知种类分种检索表。该新种与在中国墨脱和印度那加兰邦地区分布的拟平盾钩瓣叶蜂M. pseudoplanata Saini et al., 1996最近似,但新种的雌虫体长13.5 mm,后足胫节端部1/3完全黑色,触角2.5倍长于头宽,单眼后区宽长比为1.6,雄虫抱器向顶部弱度变窄等,与后者不同。新种模式标本保存于中南林业科技大学昆虫模式标本室。 相似文献
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