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1.
Nesticuscitrinus, a species originally placed in Theridion is redescribed based on the syntype series composed by 7 females and a lectotype is designated. All syntypes have broken emboli in their epigynes. Taxonomic position of “Nesticuscitrinus is briefly discussed and its belonging to Nesticidae is doubted.  相似文献   

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Within the Late Neogene Glyptodontidae of the Pampean region of Argentina, “Urotherium antiquum” was described on the basis of some associated osteoderms of the dorsal carapace, which in addition include a partial skull and left hemimandible. The diagnostic characters are located on the exposed surface of the osteoderms of the dorsal carapace which somewhat resembles those of the Pleistocene genus Neuryurus. Although the relationship of “Uantiquum” to the remaining Glyptodontidae has never been clarified, some cladistic analyses suggest a close phylogenetic affinity with the clade composed of Plohophorus + (Glyptodon + Doedicurus). A careful comparison of “Uantiquum” to well-characterized taxa with similar stratigraphic and geographic provenance reveals that no significant skull differences are observed from Plohophorus figuratus Ameghino. It seems likely that the alleged ornamentation pattern that characterizes this species was produced by a taphonomic alteration of the exposed surface of the osteoderms, a process broadly distributed in glyptodonts having a “rosette” ornamentation pattern. Finally, some characters present in the osteoderms of the type specimen of “Uantiquum” suggest that it may be a juvenile specimen. In summary, “Uantiquum” should be considered a junior synonym of Pfiguratus.  相似文献   

4.
By means of mitochondrial 12S rRNA sequencing of putative “yeti”, “bigfoot”, and other “anomalous primate” hair samples, a recent study concluded that two samples, presented as from the Himalayas, do not belong to an “anomalous primate”, but to an unknown, anomalous type of ursid. That is, that they match 12S rRNA sequences of a fossil Polar Bear (Ursus maritimus), but neither of modern Polar Bears, nor of Brown Bears (Ursus arctos), the closest relative of Polar Bears, and one that occurs today in the Himalayas. We have undertaken direct comparison of sequences; replication of the original comparative study; inference of phylogenetic relationships of the two samples with respect to those from all extant species of Ursidae (except for the Giant Panda, Ailuropoda melanoleuca) and two extinct Pleistocene species; and application of a non-tree-based population aggregation approach for species diagnosis and identification. Our results demonstrate that the very short fragment of the 12S rRNA gene sequenced by Sykes et al. is not sufficiently informative to support the hypotheses provided by these authors with respect to the taxonomic identity of the individuals from which these sequences were obtained. We have concluded that there is no reason to believe that the two samples came from anything other than Brown Bears. These analyses afforded an opportunity to test the monophyly of morphologically defined species and to comment on both their phylogenetic relationships and future efforts necessary to advance our understanding of ursid systematics.  相似文献   

5.
The bis(heptalene)dimetal complexes (C12H10)2M2 of the first row transition metals from Ti to Ni are predicted by density functional theory to exhibit “submarine” sandwich structures with a pair of metal atoms sandwiched between the two heptalene rings. For the early transition metal derivatives (C12H10)2M2 (M = V, Cr) there are two types of such structures. In one structural type the metals are sandwiched between two heptahapto heptalene rings with metal-metal distances (3.5–3.8 Å) too long for direct metal-metal bonding. The other type of (C12H10)2M2 (M = V, Cr, Mn) structure has a pair of bonded metal atoms sandwiched between a fully bonded heptalene ligand and a heptalene ligand bonded to the metals only through an eight-carbon heptafulvene subunit, leaving an uncomplexed cis-1,3-diene unit. The formal metal-metal bond orders in these latter structures are 3, 2, and 1 for M = V, Cr, and Mn with predicted bond lengths of 2.5, 2.7, and 2.8 Å, respectively. For (C12H10)2Fe2 a singlet structure with each iron atom sandwiched between a hexahapto and a tetrahapto heptalene ring is energetically preferred over an alternate structure with ferrocene-like iron atoms sandwiched between two pentahapto heptalene rings. Partial bonding of each heptalene ring to the metal atoms occurs in the late transition metal derivatives (C12H10)2M2 (M = Co, Ni). This leads to an unsymmetrical structure for the cobalt derivative and a structure for the nickel derivative with each nickel atom sandwiched between a trihapto ligand and a tetrahapto ligand.
Figure
The bis(heptalene) dimetal complexes (C12H10)2M2 (M = Ti to Ni) are predicted by density functional theory to have a “submarine” sandwich structure with a pair of metal atoms sandwiched between the two heptalene rings. In the early transition metal derivatives (C12H10)2M2 (M = V, Cr) the metal atoms are sandwiched between two heptahapto heptalene rings. In contrast, for (C12H10)2M2 (M = Mn, Fe, Co, Ni) the heptalene rings are only partially bonded to the metal atoms.  相似文献   

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在生物课的学习过程中,常见有许多同学乃至个别教师在作业、试卷、读书当中,将“膈膜”写作“隔膜”,将“栅(zha)栏组织”读作“栅(shan)栏组织”。笔者在此提出异议与各位同学及同仁商榷。“膈”,也叫“横隔膜”,是人和哺乳动物的胸腔和腹腔之间的肌膜结构,它是一块骨路肌,属于名词。而“隔”是“分开”、“间隔”的意思,属于动词。因此,人和哺乳动物胸腔和腹腔的特有结构应是“隔”,而不是“隔”。关于“栅”,在《现代汉语词典》中,有两种读音、两种解释:(l)栅(Zhd):[栅栏」:用铁条或木条做成的类似篱笆而较坚固…  相似文献   

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A taxonomic review of the Vaccinieae (Ericaceae) from the region known as Murrí (Antioquia Department, Colombia) is presented. This area has the highest generic and specific diversity of Vaccinieae known in the Neotropics, with 10 genera and 45 species.Cavendishia antioquiensis, C. viridiflora, Psammisia citrina, andP. mediobullata are newly described and illustrated.Cavendishia sessiliflora andSatyria latifolia are redescribed from complete collections. Pollination by hummingbirds in neotropical Vaccinieae is discussed and nectar content is reported for the first time for 26 species.
Resumen  Se presenta una revisión taxonómica de la tribu Vaccinieae (Ericaceae) de la región conocida como Murrí (Departamento de Antioquia, Colombia). Esta área tiene la diversidad más alta tanto en géneros como en especies de esta tribu conocidos en el Neotrópico, con 10 géneros y 45 especies. Aquí se describenCavendishia antioquiensis, C. viridiflora, Psammisia citrina, yP. mediobullata con sus respectivas ilustraciones. Se redescribenCavendishia sessiliflora ySatyria latifolia de colecciones completas. También se discute polinización de Vaccinieae por colibríes en el Neotrópico y se incluye el contenido de nectar registrado por primera vez para 26 especies.
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8.
An identification guide is presented for species of calanoid copepod family Diaptomidae from “de la Plata” River Basin (Argentina, Brazil, Bolivia, Paraguay and Uruguay). It was based on material collected during the summer and winter of 2010 from 43 sites across the eastern part and the lower stretches of this basin, the second largest in South America and the fourth in the world. The guide contains identification keys and species diagnoses for males and females, richly supported by scanning electronic micrographs and/or line drawings of 19 species. It also includes some general remarks on the taxonomy and phylogenetic relationships of these species. The key was adjusted to be useful for these species only, with separate keys for each sex, and is the first for females of South America. One species classified herein as incertae sedis was not included in the analysis. At least ten other species have previously been recorded in the basin but were not present in our samples. This is the first attempt to compile comprehensive taxonomic information on this group of copepods in this region, and it is expected to become a useful tool for biologists and young taxonomists interested in the crustacean biota of the Neotropical region.  相似文献   

9.
INTRODUCTIONThis paper deals with all the fossil molluscs collected respectively by Dr.P.Li's party in1956 and Dr.T.H.Yin's party in 1957 of the Institute of Geology,Academia Sinica.Pre-liminary reports regarding the discovery of the Ordovician in the Paiyangho region has been madeby Li,and Yang(1957),and Li,Hsieh and Ho(1958),while the writer had twice reported  相似文献   

10.
沈孝辉 《人与生物圈》2010,(3):84-93,F0002
<正>从长白山南坡穿越到西坡是一路下行,有如闲庭信步,轻松自如:然而从西坡穿越到北坡则是一路上行,特别是要翻越火山口上的几座峥嵘险峻的山峰,如同探险,需要有一定的体力和胆量,也需要有一定登山经验的领队才能完成。我约了精于此道的长白山自然博物馆馆长朴龙国,他带了三名助手到长白山西坡和我的一行(也是四人)会合。  相似文献   

11.
美丽的“笠披”与弯襟衣经过上千年的发展、变化,闽西南客家人的着装与当地人相差无几,只是妇女的服装头帕别具风采。客家女至今仍穿着弯襟布扣的衣裳。这种衣裳用黑或蓝色粗布,手工裁剪而成。它的前襟开口由右边向腋下弯曲(与旗袍式样略同),用布打结成扣子和扣眼,一件衣服一般由7或9个布扣连在一起。布扣的形状、式  相似文献   

12.
据史料载,从晋朝至清末的千余年间,黄河中下游一带由于战乱、饥荒等原因,汉族人先后出现五次大规模南迁,辗转来到赣、闽、粵和台湾等地。“先居是主,后来是客”,他们被当地人称为“客家”。目前,客家人散居在全世界的几十个国家和地区,总人口约4700万;我国约有客家人口3500万以上,他们的衣食起居、精神风貌无不体现古代中原的文化传统。这里记述的是居住在闽西南山区的客家人保留至今的独特风俗。  相似文献   

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“溴”结构域是近 10年来发现的广泛存在于多种真核生物中的保守结构域 ,由 6 0~ 110个高度保守的氨基酸残基组成 ,有形成双性α螺旋的潜能 .常见的“溴”结构域含 6 0或 110个氨基酸残基 .“溴”结构域蛋白一般有 1~5个“溴”结构域拷贝 ,这类蛋白质“溴”基序所在位置变异颇多 ,已经登录的“溴”结构域蛋白有 5 0余种 .“溴”结构域的空间结构相似 .含 6 0或 110个氨基酸残基的“溴”结构域可分别形成两个或四个反向平行的α螺旋 .P/CAF“溴”结构域的空间构型为左手旋转反向平行的上下四螺旋束状结构 ,由αZ、αA、αB和αC四…  相似文献   

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The occurrence of ice-ice disease in farmedKappaphycus spp. has tremendous implication on thecarrageenan industry in the Philippines. To elucidate the effect of thisdiseaseon the carrageenan quality, the chemical profile of carrageenan extracted fromhealthy and diseased Kappaphycus striatumsacol strain, was investigated using 13C and1H NMR, FT-IR and GPC methods of analysis. The native carrageenanextracts were composed predominantly of kappa carrageenan with trace amounts ofiota and 6-O-methylated carrageenan. Structural evidence indicatesdepolymerization of carrageenan from the ice-ice infectedportion of the thallus (whitish and soft part) lowered levels of iota andmethylconstituents. This finding was correlated to its low number average molecularweight (30 kDa) value. Accordingly, appreciable decreases incarrageenan yield, gel strength and viscosity and increase in syneresis indexwere noted. On the other hand, archetype quality of kappa-carrageenan wasobserved from both healthy and uninfected portion of the diseased thalli.  相似文献   

17.
Mean selenium contents of liver, heart muscle and skeletal muscle of pigs with dietetic microangiopathy (MAP), but without waxy muscle degeneration (MD) and hepatosis diaetetica (HD), were 1113, 850 and 265 ng/g d.s., respectively. These values were not lower than corresponding values of control pigs without MAP, MD and HD.  相似文献   

18.
Scopelophila cataractae, one of the so-called copper mosses, has a broad geographic distribution that includes North, Central, and South America, Europe, and Asia, but is rare throughout its range. A genetic analysis of 32 populations from the United States, Europe, and Asia based on 15 putative allozyme loci indicates that levels of genetic diversity vary among geographic regions. Six European populations are fixed for the same alleles at all 15 loci, consistent with the hypothesis thatS. cataractae is a recent immigrant in that region. The species is more diverse in the U.S., where it appears to be native. Five populations collected on copper-enriched soils around shrines and temples in Tokyo are genetically monomorphic, but Asian populations from another Japanese site, India, and Nepal are exceptionally diverse in terms of numbers of alleles and multilocus haplotypes, total gene diversity (HT), and in the degree of differentiation among populations (measured as Nei'sI andD). Long-distance dispersal has probably played an important role in the geographic history ofS. cataractae, but the species appears to be native in both the New and Old Worlds. Gene flow between plants disjunct on different continents is insufficient to explain the lack of geographically correlated morphological and genetic differentiation inS. cataractae.  相似文献   

19.
The fine structure of the four ocelli ofAnoplodactylus petiolatus was examined using serial longitudinal and transversal sections of the eye hill. Each pigment cup ocellus is composed of a (planconvex) cuticular lens, lens forming hypodermal cells, inverse retinula cells with latticed rhabdom and surrounding tapetum and pigment layers. Within the retinula cells a distal “vitreous” zone, a nucleus zone and a proximal rhabdomeric zone can be distinguished. Retinula cell axons originate proximally. The tapetum cells contain several layers of reflecting crystals. Distally, they have a common microvillous region. The intraretinal “vitreous” zone contains glycogen-like particles in the centre and rough ER in the periphery. Contrary to other Pantopoda vitreous cells, a praeretinal membrane and a vertical lens groove have not been observed inAnoplodactylus. While the presence of four (median) ocelli appears to be a primitive characteristic, the inverse orientation of the retinula cells in combination with a tapetum lucidum represents a highly derived characteristic among arthropod median eyes.  相似文献   

20.
Conclusion La présentation du programme de recherches du Laboratorium voor E-kologie en Systematiek doit être comprise comme étant une partie d'un programme interdisciplinaire. Les communications qui suivent n'ont donc de sens que si elles sont mises dans un contexte plus général.  相似文献   

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