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1.
<正> While helping to curate the jumbled specimens accumulated at the Shanwang Paleontological Museum in 1985, the senior authors of the present paper were happy enough to find a tapirid specimen. Through careful preparation it turned out to be a part of articulated skeleton consisting of skull, lower jaw, cervical and some anterior dorsal vertebrae and a scapula. As most of the other fossils from Shanwang, it is laterally compressed, therefore, no width could actually be measured. The nasal bones of the skull have become vertically oriented through compression. Otherwise the skull is little deformed. In order to study the tooth morphology closely, we had to extract most of the teeth from the left side of the tightly occlused tooth battery. All this notwithstanding, the skull represents one of the few well preserved specimens among the tapirid fossils ever found.  相似文献   

2.
Two genera of fangless homalopsid snakes Brachyorrhos and Calamophis from eastern Indonesia have been described as basal members of the clade. A third genus belonging to this group from Sumatra, Indonesia is described here based upon morphology. Fangless homalopsid snakes share 19 dorsal scale rows at mid-body, fused dorsal scales above the cloaca, 5 to 7 upper labials, divided anal plate, divided subcaudals, 15–21 teeth on the dentary, frontal bone about 23% of skull length and other morphological characters that suggest they are related. All the three genera are known only from Indonesia. The new genus and species have a distinctive skull morphology with an absent premaxilla, a more depressed skull, and a larger eye than are present in Brachyorrhos.  相似文献   

3.
A new kind of marattialean raches are reported from the coal balls in Coal Seam No.7 in the upper part of the Taiyuan Formation (early Early Permian) from Taiyuan, Shanxi, China and are assigned to the genus Stipitopteris Grand'Eury (Psaroniaceae). The present specimens are different from all six reported species of the genus, and are therefore proposed as a new species: Stipitopteris shanxiensis. The raches of the new species are generally dorsi-ventrally flattened. The main raches usually exhibit scales of different forms on their surface. Beneath the epidermis is a zone of parenchymatous cells, some of which contain tannin-like contents. Inside this is a zone of small sclerenchymatous cells. Inward are the ground tissue and vascular bundles. The vascular bundles are continuous and are in two circles: the outer circle assumes a transversely elliptical shape with the gap and pinna trace, and the inner circle assumes a shallow C.shape with inrolled ends. The ground tissue located at the inner side of the vascular bundle is composed of thicker-walled parenchymatous cells. The cells of the ground tissue are vertically elongated in longitudinal sections. Subordered raches are smaller and have simpler structures than the main raches. The parenchyma zone beneath the epidermis is thinner, usually one to two cells wide and the sclerenchyma zone is usually absent. The scales are poorly developed and there is only one C-shaped vascular bundle. The new species is comparable to the crosiers of Psaroniaceae of the Euramerican Flora in some aspects, for example, it has a dorsi-ventrally flattened rachis and scales on the surface of the rachis. However, the other features and the preservative conditions of the present specimens indicate that they are not crosiers, but fully developed or mature raches. The new species is the first well-studied anatomically-preserved rachis of Psaroniaceae from the Cathaysian Flora and bears significance not only in understanding the anatomy and taxonomy of Psaroniaceae in the Cathaysian Flora, but also in the relationship between the Euramerican Flora and the Cathaysian Flora.  相似文献   

4.
YANGTZEDONTA——A PROBLEMATIC BIVALVIA FROM THE MEISHUCUNIAN STAGE, CHINA   总被引:3,自引:0,他引:3  
During the last 20 years, as in studies of other molluscan groups, new progress has been made in researches on the Cambrian bivalvia with the discovery of some new genera and species such as Fordilla siberica Krasilova (1977) from the Lower Cambrian Atdabanian Stage of the Siberian Platform, USSR, Pojetaia rvnnegari Jell (1980) from the Lower Cambrian Parara Limestone Bed of Southern Australia and Tuarangia paparua Mackinnon (1982) from the Middle Cambrian Tasman Formation of New Zealand. In China, although there were also reports on the Cambrian fossil bivalves in the past, it is still difficult to determine the taxonomic position of these fossils because in these described specimens no definite hinge structures can be seen, nor exist any reliable indications of muscle scars. In 1981, while identifying some molluscan fossils from the Lower Cambrian Xinji Formation in Luonan, Shaanxi, the writer discovered the geuns Po]etaia associated with Anabcrella Vostokova, 1962 and Pelagiellids (Yu, 1983: Yu, Xu e  相似文献   

5.
This paper reports the genus Erotis Meyrick for the first time from China. Two new species Erotis expansa sp. nov. and Erotis punctalosa sp. nov. are described. E. expansa sp. nov. is related to E. phosphora Meyrick both in appearance and in the male genitalia, but can be differentiated from the latter by uncus broader and slightly concave at middle of caudal margin, gnathos nearly as long as uncus and valva with costa almost straight in the male genitalia. E. punctalosa resembles E. expansa sp. nov. externally, but can be easily distinguished from the latter by the female genitalia: eighth tergite caudally almost straight; two signa large thorn-like, basal plate irregularly triangular in shape, with fine spines along anterior margin. The photographs of the adults and the genital structures of the new species are provided. A key to all the known species of Erotis is given.  相似文献   

6.
<正> The mollusk shell mobilizes calcium from environment for skeletal mineralization.This occurs through synthesizing solidsin solution in the presence of organic molecules of specific interior regions of the conch shell.The ultrastructure and microhardnessof the Hemifusus tuba conch shell living in the Huang/Bo sea area are investigated in the paper.It is shown that thecomposition and microstructure of the mollusk shell vary in different positions.The prodissoconch shell consists only of aragonitewith the crossed-lamellar microstructure.While the spiral shell and the body shell of the Hemifusus tuba conch shell arecomposed of one calcite layer and several aragonite layers.The calcite layer consists of cylindrical grains,but the aragonitelayers are crossed-lamellar ultrastructure at three size scales.The minimum structure size (the third-order lamella) is at about20 nm - 80 nm.The margin of shell aperture is only composed of calcite with cylindrical grains.This natural optimization of theshell microstructure is intimately due to the growth of the Organic matrix.At different positions the microhardness of molluscshell is different due to different crystal structures and crystal arrangements.The growth process of shells allows a constantrenewal of the material,thus enabling their functional adaptation to external environments.  相似文献   

7.
A universal method of molecular dating that can be applied to all families and genera regardless of their fossil records, or lack thereof, is highly desirable. A possible method for eudicots is to use a large phylogeny calibrated using deep fossils including tricolpate pollen as a fixed (124 mya) calibration point. This method was used to calculate node ages within three species-poor disjunct basal eudicot genera, Caulophyllum, Podophyllum and Pachysandra, and sensitivity of these ages to effects such as taxon sampling were then quantified. By deleting from one to three accessions related to each genus in 112 different combinations, a confidence range describing variation due only to taxon sampling was generated. Ranges for Caulophyllum, Podophyllum and Pachysandra were 8.4-10.6, 7.6-20.0, and 17.6-25.0 mya, respectively. However, the confidence ranges calculated using bootstrapping were much wider, at 3-19, 0-32 and 11-32 mya, respectively. Furthermore, deleting 10 adjacent taxa had a large effect in Pachysandra only, indicating that undersampling effects are significant among Buxales. Changes to sampling density in neighboring clades, or to the position of the fixed fossil calibration point had small to negligible effects. Non-parametric rate smoothing was more sensitive to taxon sampling effects than was penalized likelihood. The wide range for Podophyllum, compared to the other two genera, was probably due to a high degree of rate heterogeneity within this genus. Confidence ranges calculated by this method could be narrowed by sampling more individuals within the genus of interest, and by sequencing multiple DNA regions from all species in the phylogeny.  相似文献   

8.
《动物分类学报》2017,(1):59-64
Freshwater planorbid mollusks belonging to the genus Biomphalaria act as intermediate hosts for Schistosoma mansoni,the etiological agent of human intestinal schistosomiasis,in the Neotropical Region.Identification ofBiomphalaria spp.are carried out based on morphological characters,and the Schistosoma infection are determined by the presence of cercariae (verified through microscope preparation and mounting).Recently,the geometric morphometrics has proven to be a useful tool for determining shape differences in disease vectors arthropods.Due to this,we used geometric morphometrics to determine Biomphalaria glabrata shell differences (shape and size)between uninfected and infected specimens.We digitalized 12 anatomical points over the shell left side (from umbilicus to the last whorl) by combining type Ⅰ and Ⅱ landmarks and sliding semilandmarks;the coordinates were aligned by generalized Procrustes analysis.Principal component analyses were implemented for examining main variation axes,and discriminant analysis for testing group membership significance.We found significant separation between infected and uninfected shell conformation.All specimens were 100%correctly classified.The main differences occur in the peristome.The Kruskal-Wallis test finds significant differences in shell isometric size among infected and uninfected specimens.These findings correspond to other studies of traditional morphometrics,that infected snails showed the reduction in shell size in contrast to those uninfected specimens.  相似文献   

9.
Clematis sect. Atragene is revised in this paper based on the examination of a large number of herbarium specimens, extensive field observations, and morphometric analyses. Brief taxonomic history and geographical distribution of the section are given, the relationships among the species are discussed, and the evolutionary trends of some characters in the section are evaluated. The staminodes of the plants in this section may have evolved from the outer stamens with petaloid filaments and gradually disappearing anthers. Subsequently, they may have evolved in two different ways. One possibility is that the staminodes elongate and become lanceolate, as long as sepals, and their apices turn into attenuate. The other is that the staminodes are spathulate, but not elongating, as long as stamens, and their apices turn into retuse from obtuse and rounded. The evolutionary trend of sepals may be from thin to thick in texture, and the veins from non-prominent to prominent. As a result, five new series are established and nine species, two subspecies and nine varieties (including three new ranks) are recognized in this section. An identification key is provided, and each taxon is described and illustrated. Clematis sibirica and Clematis ochotensis are treated as subspecies of Clematis alpina due to their subtle differences and lack of, or few, overlapping distributions. Clematis fusijamana and Clematisfauriei are recognized as varieties of C. alpina ssp. ochotensis for the continuous variation of the velutinous strips on the sepal margins. Clematis iliensis is treated as variety of C. alpina ssp. sibirica for the continuous variation of leaf division types. Extensive variations in sepal color and basal caruncle size support degrading Clematis chiisanensis as a variety of Clematis koreana. The North American ser. Occientales may be primitive, whereas ser. Macropetalae may be the most advanced taxon in this section. Ser. Alpinae and ser. Koreanae are closely related to each other. However, the systematic position of ser.  相似文献   

10.
Cytological characters of four species in Syncalathium (Asteraceae: Lactuceae), a small genus with six identified species endemic to alpine scree of the Sino-Himalayan region, are surveyed in this report. Three species (Syncalathiumpilosum, Syncalathium chrysocephalum, and Syncalathium disciforme) are examined for the first time. Combined with our previous counts, five species have been cytologically investigated from the genus and the results indicated that all species are diploid with the basic somatic chromosome number of x=8. The karyotype asymmetry of Syncalathium souliei is 2A, distinct from the other four species of 1A, and the remaining species are divided into two subgroups with different karyotypes, consistent with their morphological features. The significance of the cytological evolution of Syncalathium is briefly discussed.  相似文献   

11.
Three ganera and five species of Urostylidae are reported from China inthe present paper, three species belonging to the genus Urolabida, one toUrochela and one to Urochellus. Among them, a species is recorded for thefirst time from this country, while all the ramaining are described as new toscience. The type species are separately deposited in the Institute of Zoology,Academia Sinica and the Department of Biology, Nankai University. All themeasurements are in millimeters.  相似文献   

12.
<正> The fossils which form the subject of the present study were collected in the recent years from the middle Miocene Xiacaowan Formation at three sites, Songlinzhuang, Shuanggou and Zhengji of Sihong, Jiangsu. Most of the material from the first two sites have been reported previously as Prosciurus sp. (Li et al., 1983). Further study indicates that all the specimens mentioned and the M_1/2 previously assigned to Prosciurus? shantungensis Rensberger et Li (1986) are quite different from those of Prosciurus, but represent a new genus, Ansomys. In some features, the new form resembles Plesispermorphilus? descedens of Europe. For the two taxa a new subfamily Ansomyinae is created. It is morphologically intermediate between Meniscomyinae and Allomyinae, and may be the sister taxon of the higher aplodontids Allomyinae and Aplodontinae.  相似文献   

13.
Cornukaempferia is a recently described genus of Zingiberaceae which only occurs in Thailand as a rare genus with limited geographical distribution. Only three species have been described so far, including a recently described new species, C. larsenii. These three species are morphologically very similar and additional data on other biological aspects are useful for the elucidation of their relationship. Pollen morphology of all three species of genus Cornukaempferia has been studied by light microscopy and scanning electron microscopy. The pollen grains are monad, spherical, inaperturate. The exine sculpture is echinate with psilate between the spines for C. aurantiflora and C. longipetiolata, or echinate with regulate between the spines for C. larsenii. This observation helps support the taxonomic status of C. larsenii.  相似文献   

14.
A new genus Amblomma gen. nov. of fossil beetles is erected and can be assignedto the family Ommatidae because its two procoxal cavities are contiguous and the articulations of the abdominal ventrites are abutting. The new genus is similar to Zygadenia Handlirsch, 1906 (=Notocupes Ponomarenko, 1964), Tetraphalerus Waterhouse, 1901,Rhobdocupes Ponomarenko, 1966 and Sinocupes Lin, 1976, but can be distinguished from other genera according to the following characters: the second segment of antennae is shorterthan the third one in length; the posterior tarsi with the basal segment is obviously shorter than the three following taken together in length; the antennae reach the posterior ridge of prothroax in length, and the sides of the prothroax with serrulate margin. Four new species of the new genus are described and figured: Amblomma psilata gen. et sp. nov., Amblomma rudis gen. et sp. nov., Amblomma epicharis gen. et sp. nov., and Amblomma stabilis gen. etsp. nov. A key to species within this new genus is provided. All the specimens are collected from the Late Jurassic Yixian Formation of western Liaoning and are now housed in the College of Life Science, Capital Normal University, Beijing, China.  相似文献   

15.
In this paper five new species of Lasiocampidae are described: three belong-ing to the genus Dendrolimus,one to Hoenimnema and the other to Cyclophrag-ma, which are collected from Qinling Forest Region.All the type specimensare kept in the Institute of Zoology, Academia Sinica.  相似文献   

16.
Malaria continues to exert a huge toll in the world today, causing approximately 400 million cases and killing between 1-2 million people annually. Most of the malaria burden is borne by countries in Africa. For this reason, the major vector for malaria in this continent, Anopheles gambiae, is under intense study. With the completion of the draft sequence of this important vector, efforts are underway to develop novel control strategies. One promising area is to harness the power of the innate immunity of this mosquito species to block the transmission of the malaria parasites. Recent studies have demonstrated that Toll and Imd signaling pathways and other immunity-related genes (encoding proteins possibly function in recognition or as effector molecules) play significant roles in two different arms of innate immunity: level of infection intensity and melanization of Plasmodium oocysts. The challenges in the future are to understand how the functions of these different genes are coordinated in defense against malaria parasites, and if different arms of innate immunity are cross-regulated or coordinated.  相似文献   

17.
Some mammalian fossils collected by the authors in Autumn of 1963 from thewestern part of Zungarica Basin in Sinkiang are described in the present notes.Thelocality lies in the extreme west of Zungarica Basin at Ta-ku-sze-tai valley of Wenquandistrict on the southern side of the Altao Mountains,and it is the first Tertiary localityin Sinkiang represented by a mammalian assemblage,the stratigraphic occurrence ofwhich is known.The fossils are rather well preserved and occur in a clay“pocket”intercalated as a lens in a series of sandstones,marls and conglomerates.The age ofthe fossil bearing Tertiary beds at Ta-ku-sze-tai is Early Pliocene as characterized bythe presence of Gazella dorcadoides,Indarctos sinensis and?Lycyaena dubia,which arethe common elements of Hipparion fauna in North China.  相似文献   

18.
The classification and evolutionary relationships are important issues in the study of the groupers. Cytochrome b gene fragment of twenty-eight grouper species within six genera of subfamily Epinephelinae was amplified using PCR techniques and the sequences were analyzed to derive the phylogenetic relationships of the groupers from the China Seas. Genetic information indexes, including Kimura-2 parameter genetic distance and Ts/Tv ratios, were generated by using a variety of biology softwares. With Niphon spinosus, Pagrus major and Pagrus auriga as the designated outgroups, phylogenetic trees, which invoke additional homologous sequences of other Epinephelus fishes from GenBank, were constructed based on the neighbor-joining (NJ), maximum-parsimony (MP), maximum-likelihood (ML) and minimum-evolution (ME) methods. Several conclusions were drawn from the DNA sequences analysis: (1) genus Plectropomus, which was early diverged, is the most primitive group in the subfamily Epinephelinae; (2) genus Variola is more closely related to genus Cephalopolis than the other four genera; (3) genus Cephalopolis is a monophyletic group and more primitive than genus Epinephelus; (4) Promicrops lanceolatus and Cromileptes altivelis should be included in genus Epinephelus; (5) there exist two sister groups in genus Epinephelus.  相似文献   

19.
One new genus and two new species of Membracidae are described inthis paper. As a token of honor to our teacher, Professor Chou Io, whostarted the research on membracid taxonomy in China, this new genus isnamed Choucentrus. Two new secies belong to this genus. One of them iscollected from Yunnan and Xizang Province,China,another is collected fromTonkin, Vietman. All the type specimens are kept in the Institute of Zoology,Academia Sinica.  相似文献   

20.
The present paper deals with four species belonging to three genera, in which a genus (Paraletabo gen. nov.) and four species are described as new to science, a genus (Sophianus Distant) is recorded for the first time from China. The type specimens are deposited in the Department of Biology, Nankai University. The new genus and new species are briefly diangnosed as follows.  相似文献   

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