949 resultados para Walker Museum of Paleontology
Resumo:
Sea cucumbers belong to phylum Echinodermata, order Holothuroidea are an abundant and diverse group of Invertebrates, with over 1400 species occuring from the intertidal to the deepest oceanic trenches. Sea cucumbers are important components of the food chain in temperate and coral reef ecosystems and they play an important role as deposite feeders and suspension feeders. Rapid decline in populations may have serious consequences for the survival of other species that are part of the same complex food web,as the eggs, larve and juveniles constitute an important food source for the other marine species including crustaceans, fish and mollusks. In addition sea cucumbers are often called the earthworms of the sea, because they are responsible for the extensive shifting and mixing of the substrate, and recycling of detrital matter. Sea cucumbers consume and grind sediment and organic material into finer particles , turning over the top layers of sediment in lagoons , reefs and other habitats and allowing the penetration of oxygen. While the taxonomy of the holothurian families is generally well known , the distinction of similar species is difficult. There are relatively few holothurian taxonomist.Most sea cucumber species can be identified by Holothurin taxonomists by using the calcareous skeletal ossicles found in the body wall. In this study , at first a sea cucumber from Kish island in Persian gulf has recognized. Individuals collected from west and east extend far away into north and south of coral reefs by diving. I have checked them morphologically and anatomically.Then with key to the orders of the Holothuroidea, They belong to the Aspidochirotida with key to the families of Aspidochirotida, they were in Stichopodidae families and with key to the genus of Stchopodidae, they were Stichopus. Then ossicles were extracted at National Museum of Natural History, by Dr David Pawson. The ossicles were measured on a transect across a slide prepared from the mid-dorsal region of each specimen.The one we have in the shallow waters of Kish island, is Stichopus hermanni, a massive holothurian, body broad, considerably flattened ventraly ,the dorsal side slightly arched and the lateral sides almost vertical; body wall fairy thick and soft ; mouth subterminal; anus central; tentacles usually 20 in number of length and leaf shaped. Numerous ossicles consisting of table with large discs having usually 7 to 15 peripheral holes, but often irregular or incomplete and spire of moderate height ending in a group of spinelets, rosettes of variable development, and c-shaped rods. Color (exept papillae)partly remained after preservation in alcohol which is found at the depth of 4 to 8 meters, on coral reef. Furthermore, the sexual reproductive cycle was described using standard methods. Gonads were removed and transferred to Bouin's fixative for four weeks and then processed according to standard embedding technique. To prevent the loss of tubule contents during embedding, the tubule sections, were cut well beyond the segment selected for sectioning. For each individual, six sections, each section with 5µm diameter by microtome were cut from tubules. These sections were first placed on gelatin coated slides (the gelatin was heated to 42°c) and then transferred to the oven at 37°c for one hour. This technique usually prevents the fragil tubules from breaking and the loss of gametes. The slides were stained with Eosin and Hematoxylin, and good resolution of the various cell types achieved.A second series of slides was stained with the Periodic Acid Schiff(PAS) to identify polysaccharides(glycogen). Monthly sampling was occurred.The sexual reproductive cycle was defined through the combined use of these criteria: Monthly percentages of the gonad stages for each sex, the monthly gonad index (GI) , given as the ratio of the wet gonad weight (G) to the dray weight (DW)and the monthly percentage of individuals that undetermined sex. The gonad consists of two tufts of tubules on which saccules develop. Gonadal development was classified into five stages: post spawning, recovery, growth, advanced growth, and mature stage that were adapted from the earlier studies of holothurians. Histological preparations showed that the sex of larger individuals could be identified by the presence of oogonia and young oocytes in females, and spermatogonic stages in males.The mean diameter of the tubules and gonadal mass follow annual cycles, increasing from late winter through spring, and dropping abruptly after spawning in the summer. Gametogenesis is generally a prolongate process and begins in March. By summer the ovarian tubules contain oocytes with diameter of 120-240 pm and the testicular tubules contain an abundance of spermatozoa (diameter 5-6 gm ).Following spawning the predominant activity within the spent tubules is phagocytosis of the residual gamets.The active phase of gametogenesis (March to July), coincides with an increasing photoperiod regim, and an accelerated gametogenesis occurs in July when temperature is high. Throughout the year, the gonad of Stichopus hermanni is larger in males than in females, and this is due to the number of tubules in the testis rather than to tubules length or diameter.
Resumo:
A new genus of Cobitinae, Bibarba gen. n., and a new species, B. bibarba sp. n., were discovered and are described for the Chengjiang River, a tributary of the Hongshuihe River in Guangxi Province of southern China. This river region is characterized by a Karst landscape, and the river that is inhabited by the new genus is a slowly moving stream with arenaceous and cobblestone beds. The new genus resembles Cobitis Linnaeus, 1758 (subfamily Cobitinae) in the shape and pigmentation pattern of their body, the absence of scales on their head, and the presence of a suborbital spine, but differs from it by a single Lamina circularis on the third pectoral fin ray instead of on the base of the second pectoral fin ray; two pairs of barbels (one rostral pair and one maxillo-mandibular pair) instead of three pairs of barbels (one rostral pair, one maxillary pair, and one maxillo-mandibular pair); a relatively thick and short suborbital spine with a strong medio-lateral process instead of a suborbital spine without or with a weakly formed medio-lateral process as in Cobitis; and the lack of a black stripe extending from the occiput through the eye to the insertion of the rostral barbel. The first two characters have not been reported in any other genus of the subfamily Cobitinae. A morphometric character analysis based on PCA reveals differences between B. bibarba and C. sinensis in body size, barbel length, interorbital width, pectoral fin length in males, and the position of the dorsal and ventral fins. Type specimens of the new species are kept in the Freshwater Fishes Museum of the Institute of Hydrobiology at the Chinese Academy of Sciences in Wuhan, Hubei Province. (c) 2007 Elsevier GmbH. All rights reserved.
A new genus of grasshopper (orthoptera : acridoidea : Catantopidae : Cyrtacanthacridinae) from China
Resumo:
This paper reports a new genus i.e. Parapachyacris gen. nov and a new species Parapachyacris taiwanensis sp. nov in Cyrtacathacridinae. The new genus is similar to Pachyacris Uvarov, 1923 and differs from the latter in: 1) foveolae lacking; 2) hind tibiae with 10 spines on inner side and 8 spines on outer side; 3) basal part of prostemal process thickened; 4) cross veins right angled with longitudinal veins in apical part of tegmina and 5) the back of body with yellow longitudinal stripe in middle. The new genus is also similar to Patanga Uvarov, 1923 and differs from the latter in: 1) foveolae lacking; 2) basal part of prostemal process thickened; 3) upper side of hind femora with three dark bands and 4) black spots of tegmina lacking. Type specimen is deposited in the National Museum of Natural Science (NMNH), Taichung, Taiwan, China.
Resumo:
During routine identification of the grasshoppers of the Dasa river, Guizhou Province of China in 2004, a new species [ Oxya guizhouensis sp, nov.] of the genus Oxya Serville ( Orthoptera, Acrididae, Catantopinae) was discovered. It is described here. A key to all known species of the genus from China is given. The type specimens are deposited in the Museum of Hebei University (MHU), Baoding, Hebei, China.
Resumo:
A new species, Atractomorpha taiwanensis sp. n. from Taiwan, China, is described in this paper. The new species is similar to A. micropenna Zheng, 1992, but it differs from the latter by the following: lateral lobe of pronotum without membranous area near posterior margin; the tegmina strongly shortened, not reaching ( in male) the midpoint of hind femur; and wings very small, not reaching the midpoint of tegmina. A key to all known species of the genus Atractomorpha from China is given. The type specimens are deposited in the Museum of Hebei University, China.
Resumo:
This paper reports a new genus and species of Catantopinae: Guizhouacris xiai gen et sp. nov. The new genus is similar to Genimen I. Bolivar, 1917, but differs from the latter in: 1) lateral lobes of metasternum separated in apical part and 2) prozona about 2.5 (male) and 2.7 (female) times longer than metazona. The new genus is also similar to Rhinopodisma Mishchenko, 1954 (= Aserratus Huang, 1981), but differs from the latter in: 1) diameter of tympanal aperture longer than half tergum and 2) face not projected between two eyes. Type specimens are deposited in the Museum of Hebei University ( MHU).
Resumo:
This paper aims to explore and discuss the role of nostalgia (a concept that is inherently grounded within a psychological framework) in heritage interpretation from both provider and consumer perspectives. Whilst many cultural practitioners recognise the relationship between sentimentality and authenticity, particularly within a folk-heritage context, few have sought to examine the effect this has on the visitor experience. This paper questions visitors’ ability to objectively assess objects and experiences at heritage sites, and the role of practitioners in presenting often blurred views of social history that may sometimes negate historical fact. Drawing on case study research at two UK living museums, Blists Hill Victorian Town in Shropshire, England, and the Big Pit: National Coal Museum in Wales, notions of reminiscence, authenticity, myth and intangibility are considered within the framework of the interpretive experience. Findings suggest that the visitor experience is inherently subjective, highly individual and that the concept of intangibility is integral to an understanding of the nostalgia-authenticity debate.
Resumo:
Women’s contribution to abstract art in the interwar period is a subject that, to date, has received very little attention. In this article we deal with the untold story of the participation of women artists in Abstraction-Création, the foremost international group dedicated to abstract art in the 1930s. Founded in Paris in 1931, the group took on the work of two previous collectives to become a platform for the dissemination and promotion of abstract art and consisted of around a hundred members. Twelve of these were women, whose writings and works were published in the group’s annual magazine, abstraction creátion art non figuratif (1932-1936), and who participated in a number of the group’s exhibitions. Compared to what had occurred in previous groups, the participation of women, although reduced in number, was comparable to that of the male artists and being members of the group had a generally positive impact on the women’s careers. However, all this came at the expense of relinquishing any gender specificity in their work and the public presentation of it, and demonstrates that the normalization of women’s contributions to the avant-garde could only be brought about alongside a questioning of the more dogmatic views of modernity.
Resumo:
Based on the analysis model favored by the study of the conditions in which the seventeenth century Querelle des Anciens et des Modernes took place, we examine the case of confrontation between realism and abstraction, which occurred in the context of Spanish art in the nineties of the twentieth century. Connections are established with other aesthetic conflicts which are considered part of a genealogy whose most explicit antecedent could be placed in the before mentioned complaint, such as the confrontation between realism and abstraction in the American art scene, which occurred in the fifties of the last century, and the more recent controversy on pluralism and the end of art.
Resumo:
Para la mentalidad colonialista del siglo XIX la raza negra estaba provista de una extraordinaria sexualidad y lujuria. En la metrópolis el equivalente era la mujer sexuada, la prostituta. En los primeros años del siglo XX este tándem, prostituta-colonizado, sirve a los artistas vanguardistas como elemento de confrontación con la moral imperante. Son las artistas mujeres, con una intención feminista, quienes principalmente utilizan el primitivismo asociado a la mujer en su crítica a los estereotipos. Figura pionera en ello es Hannah Höch, especialmente en su serie De un Museo Etnográfico, en el que asocia figuras femeninas y objetos de arte primitivo. En los años 70 del siglo XX, algunas artistas de la performance, como Carolee Schneemann o Ana Mendieta reivindican el cuerpo femenino con el significado de Origen y Fertilidad que tiene en las culturas primitivas. En este mismo contexto puede inscribirse la escultura Maman de Louise Bourgeois. El elemento de crítica social, que está vigente aún en nuestros días, puede verse en las obras de las Guerrilla Girls.
Resumo:
This paper details an international research project which examined over 50 architecture centres in 23 countries including four case study subjects:
•Kent Architecture Centre, England
•Chicago Architecture Foundation
•Museum of Finnish Architecture
•Netherlands Architecture Institute
The paper analyzes the project's main findings including issues of definition, reasons for foundation, cultural policy impact and the main goals of architecture centres. It summarizes recommendations for centres as they attempt to reach their aims.
Resumo:
Essay in a monograph associated with the exhibition Julian Opie: Sculptures, Paintings, Films at the Museum of Contemporary Art in Krakow, Poland, 18 October 2014 to 25 January 2015. Slyce attempts to re-examine the lineaments of Opie's practice for a new and broader audience. During which, he calls attention in the writing to the processes of its commissioning and early request to do so for a 'Polish audience'. He attempts to bring to light some of these often invisible moves in the commissioning of catalogue essays, while also re-examining Julian Opie's practice in light of its established reception in Britain.
Resumo:
Thesis (Master's)--University of Washington, 2015-12