Epibionts of Asellus aquaticus(L.) (Crustacea, Isopoda): an SEM study

1. This study presents a qualitative and quantitative survey of epibionts infesting two populations of the freshwater isopod Asellus aquaticus (L.). Using scanning electron microscopy, the prevalence, mean intensity, abundance, spatial preferences and distribution of organisms on various external surfaces were ascertained.
2. A diverse community, consisting primarily of protozoa and rotifers, utilised A. aquaticus as a substrate organism. Every individual A. aquaticus supported some form of epizoic life. Peritrich species comprised 89.2% of all epibionts. Carchesium polypinum, Pseudocarchesium aselli, Pseudocarchesium asellicola, Pseudocarchesium simulans and Opercularia hebes dominated the epifauna.
3. Highest epibiont burdens occurred on the mouthparts, the first few ventral segments and the gills and largely comprised the above peritrich species. Most epibionts exhibited some degree of site preference on the host. A distinct gill epifauna existed. Apart from Acineta tuberosa and Vorticella rotunda , which had equal prevalences on dorsal and ventral surfaces in one culture, most species largely avoided the dorsal surface.
4. Epibionts exhibited varying degrees of adaptation to life on a living substrate. They ranged from facultative species such as A. tuberosa , which are capable of colonising abiotic substrata, to Gymnodinoides aselli whose life cycle relies on interaction with A. aquaticus . Highly specialised species tended to exhibit the most pronounced and consistent site restriction.
5. Asellus aquaticus offers a highly tractable system for further study of substrate species–epibiont relationships.     

Systematic position and review of Deinopteroloma Jansson, 1946, with descriptions of four new species (Coleoptera, Silphidae and Staphylinidae (Omaliinae))

Abstract. The genus Deinopteroloma Jansson 1946 is transferred from the family Silphidae to the family Staphylinidae and assigned to the subfamily Omaliinae, tribe Anthophagini. The genus Mathrilaeum Moore 1966 is shown to be congeneric with Deinopteroloma and considered a junior synonym. The genus Deinopteroloma is redescribed and its position in the Anthobium group of genera is discussed. Nine species are recognized, five in the Nepal Himalayas, two in northeastern Burma and two on the Pacific coast of North America. A key for identification is given. Each species is described and illustrated and all available bionomic and distributional data are presented. Deinopteroloma crenatum, D.spectabile, D.egregium and D.insigne , all from the Nepal Himalayas, are described as new and Lathrimaeum subcostatum Maklin, L.pictum Fauvel and L.notabile Cameron are transferred in Deinopteroloma (comb.nov.). Lectotypes are designated for D.subcostatum (Mäklin), D.humerale (Casey), D.pictum (Fauvel) and D.notabile (Cameron).     

The systematic position of some nippostrongyline nematodes (Trichostrongylina: Heligmosomoidea) parasitic in Argentinean sigmodontine rodents

The systematic position of two nippostrongyline nematodes described from Argentinean sigmodontine rodents is clarified. The first species, Hassalstrongylus multiovatus Suriano & Navone, 1992, parasitic in Akodon simulator Thomas from the province of Tucumán, was studied on the basis of type and voucher material. H. multiovatus is proposed as a junior synonym of Trichofreitasia lenti Sutton & Durette-Desset, 1991, a parasite described from Oligoryzomys flavescens (Waterhouse) in the province of Buenos Aires. The holotype and three of seven paratypes deposited as H. multiovatus were identified as T. lenti. One male paratype was identified as Guerrerostrongylus uruguayensis Sutton & Durette-Desset, 1991, a parasite described from O. flavescens in Uruguay. Three female paratypes were identified as Guerrerostrongylus sp. The second species, Stilestrongylus scapteromys Suriano & Navone, 1996, parasitic in Scapteromys aquaticus Thomas from the province of Buenos Aires, was studied on voucher material. Stilestrongylus scapteromys and Malvinema frederici Digiani, Sutton & Durette-Desset, 2003, the type-species of Malvinema Digiani, Sutton & Durette-Desset, 2003, were described from the same host and geographical region. As they are considered to refer to one and the same taxon, the new combination Malvinema scapteromys n. comb. is proposed for this species.     

中国水生跳虫新种及新记录种记述 (弹尾目)

自Uchida(1948)从山西东冶县发现中国第1种水生Podura aquatica Linnaeus, 1785以来,中国弹尾目水生种类再未见报道。该文记述了采自上海植物园水塘静水表面的弹尾目5新种,水生原Podura aquatica, 尹氏球角Hypogastrura yinae sp. Nov., 沼生陷等Isotomurus palustris, 水生握角圆Sminthurides aquaticus 及刺拟勃氏圆Pseudobourletiella spinata。 其中水生握角圆和刺拟勃氏圆为中国新记录种,尹氏球角为新种。新种的模式标本及观察的其它种的标本存放在中国科学院上海昆虫研究所标本馆。     

Marker development and characterisation of Hordeum bulbosum introgression lines: a resource for barley improvement

A set of 110 diploid putative introgression lines (ILs) containing chromatin introgressed from the undomesticated species Hordeum bulbosum L. (bulbous barley grass) into cultivated barley (Hordeum vulgare L.) has been identified using a high-copy number retrotransposon-like PCR marker, pSc119.1, derived from rye (Secale cereale L.). To evaluate these lines, 92 EST-derived markers were developed by marker sequencing across four barley cultivars and four H. bulbosum genotypes. Single nucleotide polymorphisms and insertions/deletions conserved between the two species were then used to develop a set of fully informative cleaved amplified polymorphic sequence markers or size polymorphic insertion/deletion markers. Introgressed chromatin from H. bulbosum was confirmed and genetically located in 88 of these lines using 46 of the EST-derived PCR markers. A total of 96 individual introgressions were detected with most of them (94.8%) extending to the most distal marker for each respective chromosome arm. Introgressions were detected on all chromosome arms except chromosome 3HL. Interstitial or sub-distal introgressions also occurred, with two located on chromosome 2HL and one each on 3HS, 5HL and 6HS. Twenty-two putative ILs that were positive for H. bulbosum chromatin using pSc119.1 have not had introgressions detected with these single-locus markers. When all introgressions are combined, more than 36% of the barley genetic map has now been covered with introgressed chromatin from H. bulbosum. These ILs represent a significant germplasm resource for barley improvement that can be mined for diverse traits of interest to barley breeders and researchers. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Lorilichus,a new genus of feather mites (Acarina,Pterolichidae) from lories and lorikeets (Aves,Psittacidae)

Lorilichus n. g. (Pterolichidae, Pterolichinae) is restricted to the Indo-Australian parrots of the family Loriidae. Assigned to this new genus are Pterolichus (Pseudalloptes) species described by Trouessart in 1884, namely, lobiger (type-species), delibativentris, discifer, cultriventris, emargiventris and securiventris. The first three named species are illustrated and two new species, parvifolius and grandifolius, are described: the five species are from Lorius domicellus (L.).     

中国滇西天南星科一新种——保山犁头尖

描述了天南星科Araceae南星族Areae犁头尖属Tiphonium Schoa一新种——保山犁头尖Typhonium baoshanense Z.L.Dao ＆ H.Li,它的叶形和佛焰苞形态与犁头尖T.blumei Nicolson ＆ Sivadasan相似,但附属器下部,雄花序之上,有1-2轮不育雄花（退化雄蕊）,雌花序圆锥形,附属器基部截形和佛焰焰苞檐部狭窄而易于区别。同域分布的犁头尖染色体数目为2n=52,本种染色体数目为2n=10,为天南星科的最低染色体基数。     

APOMIXIS IN EUPATORIUM TANACETIFOLIUM (COMPOSITAE)

Cytogenetics and embryological studies of male sterility have been reported for the first time in Eupatorium tanacetifolium Gill, ex H. et A. (Gyptis pinnatifida Cass.). This species produces viable seeds but abnormal pollen that is not shed by the anthers. There are great abnormalities in karyokinesis and cytokinesis in microsporogenesis that result in irregular sporads formed by 5–10 cells of variable size, shape, and chromosome number. There is an irregular distribution of chromosomes, due to absence of regular pairing and disjunction, presence of chromatinic bridges in most of telophases, and to succesive aberrant cytokinesis without formation of cell plate and with variably oriented walls. The two chromatids of each chromosome presumably remain joined until the end of the process. Somatic chromosome number of 2n = 30 is reported for one population of this species, an apomict taxon of probable triploid origin. Embryo-sac ontogeny is of the Antennaria type of diplospory, wherein embryo and endosperm development are parthenogenetic.     

The food of five gadoid species during the pelagic O-group phase in the northern North Sea

The diets of five gadoid species in the northern North Sea are described: the cod, Gadus morhua (L.); haddock, Melanogrammus aeglefinus (L.); whiting, Merlangius merlangus (L.); saithe, Pollachius virens (L.); and the Norway pout, Trisopterus esmarkii (L.). The diet of each species was shown to be a gradual progression to different prey species as the predators increased in length. There were differences in the food taken by each species with respect to numbers, species and size. These differences in diet suggest that the degree of competition between pelagic O-group gadoids is not great.     

Fruit structure and generic delimitation of Athanasia (Asteraceae-Anthemideae) and related South African genera

Within South African Asteraceae-Anthemideae there is a group of genera containing furanosesquiterpenes rather than the common polyacetylenes. Of these genera, Asaemia (Harv.) Ham. ex Benth. & Hook., Athanasia L., Eumorphia DC., Gymno-pcnfzia Benth., Phymaspermum Less. and Sfilpnophyfon Less. have been investigated morphologically especially with respect to fruit structure. As a result of the investigations Stilpnophyton has been reduced to synonomy under Athanasia L. emend. Källersjö (with 36 spp.) and five species of Athanasia , together with Phaeocephalus S. Moore., are placed in the revived genus Hymenolepis Cass. (with 7 spp.). Brachymerk DC. and four misplaced species of Aihanasia are included in Phymaspermum Less. emend. Källersjö (with 17 spp.). Nine other misplaced species of Athanasia and one Pentzia Thunb. species have been described as a new genus Inulanihera Källersjö (with 10 spp.), a group without furanosesquiterpenes. The two monotypic genera Asaemia and Gymnopentzia , and Eumorphia (with 6 spp.) remain unchanged. The interrelationships of the genera possessing furanosesquiterpenes are shown in a cladogram. There are 25 new combinations in Afhanasia, Znulanthera, Hymenolepis and Phymaspermum .     

Chromosome systems in the eriococcidae (Coccoidea Homoptera)

Spermatogenesis is described in two eriococcid species and the observations are compared to those previously reported. In Gossyparia spuria the diploid chromosome number is 28 in both males and females. In the female all the chromosomes are euchromatic. In most male tissues 14 of the chromosomes are euchromatic (E) and 14 are heterochromatic (H). Prior to the first meiotic division in males the number of H chromosomes was reduced. During prophase I all the cells showed 14 E chromosomes and from 1 to over 9 H chromosomes. The range of chromosome numbers in metaphase I was similar to that in prophase I. All the chromosomes divided in anaphase I, and, following differential uncoiling at interkinesis, the E and H groups of chromosomes segregated from each other at anaphase II. Only the E groups formed sperm. The presence of a variable number of H chromosomes and a haploid number of E chromosomes in spermatogenesis suggested the presence of the multiple-D variant of the Comstockiella chromosome system. In this system some of the H chromosomes become euchromatic prior to prophase I of spermatogenesis and pair with their E homologues. All the remaining H chromosomes are thus univalents, while among the E elements, some are univalents and the rest are bivalents. The observed reduction in the number of H chromosomes in the first meiotic division which was previously attributed to pairing among the H chromosomes, is now interpreted to be the result of the return of some of the H chromosomes to a euchromatic state and to their subsequent pairing with their E homologues. Spermatogenesis in Eriococcus araucariae was similar to that of G. spuria except that the reduction in the number of H chromosomes was not as extensive. The chromosome systems of the two species are compared to those of other eriococcids and the differences are briefly discussed.Supported by grant GB1585 from the National Science Foundation, Washington, D. C.     

A Novel ZZ/ZW Sex Chromosome System for the Genus Leporinus (Pisces, Anostomidae, Characiformes)

A wide range of sex chromosome mechanisms, including simple and multiple chromosome systems is characteristic of fishes. The Leporinus genus represent a good model to study sex chromosome mechanisms, because an unambiguous ZZ/ZW sex chromosome system was previously described for seven species, while the remaining studied species of the genus do not show differentiated sex chromosomes. The occurrence of sex chromosomes in Leporinus trifasciatus and Leporinus sp2 from the Araguaia river, Amazon basin, Brazil, was here investigated. ZZ/ZW sex chromosomes were detected for both species. The Z and W chromosome morphology of L. trifasciatus is the same as described for other species of the genus Leporinus. However, the Z and W chromosomes of L. sp2 were quite different in their morphology and banding pattern suggesting that the ZW system of this species have originated independently from the ZW system previously described for other Leporinus.     

Application of Giemsa banding to orchid karyotype analysis

A method for obtaining orchid chromosome squash preparations from ovular tissues and a Giemsa C-band technique are described. Jointly applied, they result in well-defined chromosome banding patterns. Preliminary tests with two species of the genusCephalanthera show that Giemsa banding is also well suited for orchids. Besides aiding in chromosome identification and karyotype analysis, it should prove valuable in studies of chromosomal variation and karyotype evolution of this large family.     

中国独活属的核型研究

本文首次报道了我国独活属10种(含1变种)的核型,其中8种的染色体数目亦为首次报道。研究表明它们的染色体数目均为2n＝2x＝22,为二倍体,其核型为中部着丝点和亚中部着丝点染色体组成,仅具1A和2A两种类型。有4种具随体染色体,在部分H．vicinum植株中发现有1条B染色体,在H．millefolium var．longilobum中同时存在2n＝22和2n＝24的非整倍体．不同种的染色体形态不同,为分类研究提供了细胞学依据。 本文在核型分析基础上讨论了该属分类群的划分、种间亲缘关系及演化,并结合我国毗邻地区该属细胞学资料和地理分布规律,提出我国西南部的横断山区是独活属的频度中心和多样性中心。     

A comparative study on carbohydrate reserves and ethanolic fermentation in the roots of two wetland and non‐wetland species after commencement of hypoxia

The problem of availability of storage carbohydrates (fructans and starch) in oxygen‐deficient roots was investigated in wetland species ( Senecio aquaticus Hill., Myosotis palustris [L.] L. Em. Rchb.) and compared with related non‐wetland species ( Senecio jacobaea L., Myosotis arvensis [L.] Hill.) with respect to ethanolic fermentation (PDC activity, ethanol production).
In response to 24 h of hypoxic treatment, the pyruvate decarboxylase (PDC) activity in roots increased 4‐fold in M. arvensis and S. jacobaea , 2‐fold in S. aquaticus and only slightly in M. palustris . The rise in PDC activity was accompanied by an increase in ethanol content in the roots. The increase in ethanolic fermentation in roots of intact plants was associated with a slight increase in fructose and glucose and in a clear rise in sucrose content during the first 24‐48 h after commencement of the hypoxic treatment. Following 24 h of hypoxia, the content of fructans started to increase significantly for the duration of the experiment (9 days) in the four species. Since starch content changed only slightly during this period, the fructan:starch ratio increased under low energy availability. In the roots of flooding‐tolerant Senecio aquaticus , the ratio shifted most clearly from 2:1 in normoxia to 9:1 in hypoxia. For the roots of the two wetland species investigated, the results indicate a stronger accumulation of carbohydrates accompanied by a lower increase in PDC activity under root hypoxia, when compared with the related non‐wetland species respectively.     

Holcus azoricus M. Seq. & Castrov. (Poaceae), a new species from the Azores Islands

A new species of Holcus L. (Poaceae), endemic to the Azores archipelago (Portugal), is described. The vegetative and reproductive structures were studied. The diagnostic characters were compared with those of closely related species. New chromosome counts in Holcus azoricus M. Seq. & Castrov. (2 n  = 35) and H. rigidus Hochst. (2 n  = 28) are included. A possible hybrid origin is hypothesized; the potential parents are H. lanatus L. and H. rigidus .  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 259–267.     

披碱草属与大麦属系统关系的研究

禾本科中,披碱草属Elymus L.为多倍体属,约含150余种;大麦属Hordeum L.具二倍体和多倍体,约有40余种,该两属均广泛地分布于全球温带地区。该两属,尤其是披碱草属的系统分类较为困难。基于形态学的传统研究认为这两个属的系统关系较远,而细胞学研究的资料却表明,披碱草属的H染色体组起源于大麦属。笔者对来源不同的披碱草属和大麦属的物种进行了远缘杂交,并对其属间杂种F1的减数分裂中期I染色体配对行为进行了分析。结果表明,若以披碱草属作母本,该两属有相对较高的杂交亲合力,通过对杂种幼胚进行分割和离体培养,也能获得杂种F1植株。属间杂种植株的形态介于双亲之间,但更接近于披碱草属,杂种的生殖器官发育不健全,而且所有的杂种F1均完全不育。细胞学的观察结果表明,这两个属间的杂种F1通常具有较低的减数分裂中期I染色体配对数,但有较大的变异。通过笔者的工作及掌握的形态学和细胞学的资料分析认为：披碱草属和大麦属的亲缘关系较为复杂,不能一概而论。含H染色体组的披碱草属和大麦属物种有着较近的亲缘关系,但这两个属中所含的H染色体组已产生了程度不同的分化;不含H染色体组的披碱草属及大麦属的物种具有较远的亲缘关系。     

Karyotype of blue honeysuckle species (Lonicera subset. Caeruleae,Caprifoliaceae

For the first time the karyotypes of diploid (2n = 2x = 18) and tetraploid (2n = 4x = 36) species of Lonicera from the Caeruleae subsection: L. altaica Pall., L. boczkarnikowii Plekh. (L. regeliana Boczkarn.), L. edulis Turcz. ex Freyn (2x, 4x), L. emphyllocalyx Maxim., L. iliensis Pojark., L. kamtschatica Pojark., L. pallasii Ledeb., L. stenantha Pojark., L. turczaninowii Pojark., L. villosa (2x, 4x) (Michx.) Muhl. are described. The species karyotypes from 23 natural populations have shown the considerable generic resemblance that expressed in the similar chromosome morphology and variation range of their length from 1 to 3 microns. The species with the same level of ploidy had the same karyotype formula: 2m + 6sm + 1st in diploids and 4m + 11sm + 3st in tetraploids, respectively. The amphiploid origin of the tetraploid Lonicera species has been shown. Diploid and tetraploid forms of L. edulis and L. villosa were the particular karyotypes but not the 2x and 4x races of the same species, respectively. Specific differences were revealed in the total chromosome length in the haploid set and in the number of satellites and secondary constrictions. Generic resemblance and specific peculiarities of Lonicera karyotypes indicate a common center of the blue honeysuckle origin and a common initial population of karyotypes which evolved into several phylogenetic branches of the Caeruleae subsection: the Central Asiatic--L. iliensis and L. stenantha; the Siberian--L. altaica, L. edulis, and L. pallasii; the Beringian--L. emphyllocalyx, L. kamtschatica, and L. villosa; the Manchurian--L. boczkarnikowii (L. regeliana), and L. turczaninowii.