Home About us Contact
|
Home About us Contact | ||
|
|
||
History Collections (history + collection)
Kinds of History Collections Selected AbstractsPhylogenetic patterns of enamel microstructure in dinosaur teethJOURNAL OF MORPHOLOGY, Issue 2 2005Sunny H. Hwang Abstract The tooth enamel microstructure of all the dinosaur taxa that are adequately represented in the American Museum of Natural History collections were analyzed using scanning electron microscopy. This study aims to determine whether or not better sampling within a major nonmammalian amniote (hereafter referred to descriptively as "reptile") clade will unearth phylogenetic patterns in enamel microstructure in addition to those dictated by tooth function. While interest in reptile enamel microstructure has increased in the past few years, intensive sampling focused on just one monophyletic reptile clade was not previously implemented. This study reveals that phylogenetic constraints play a larger role in shaping enamel microstructure in reptiles than previously thought. Within many monophyletic dinosaur clades the combination of enamel types and enamel features within a tooth,the schmelzmuster,is the same in all the taxa due to their common ancestry, and their schmelzmusters are diagnostic of their respective clades. While distantly related taxa with similar teeth and diets have similar schmelzmusters due to functional constraints, phylogenetic constraints keep those schmelzmusters distinct from one another. An interesting finding of this analysis is that the enamel complexity of a taxon does not necessarily coincide with the position of the taxon on a phylogenetic tree; more derived taxa do not necessarily have more derived enamel and more primitive taxa do not necessarily have more primitive enamel. J. Morphol. © 2005 Wiley-Liss, Inc. [source] PERSPECTIVE: Underutilized resources for studying the evolution of invasive species during their introduction, establishment, and lag phasesEVOLUTIONARY APPLICATIONS (ELECTRONIC), Issue 2 2010Travis D. Marsico Abstract The early phases of biological invasions are poorly understood. In particular, during the introduction, establishment, and possible lag phases, it is unclear to what extent evolution must take place for an introduced species to transition from established to expanding. In this study, we highlight three disparate data sources that can provide insights into evolutionary processes associated with invasion success: biological control organisms, horticultural introductions, and natural history collections. All three data sources potentially provide introduction dates, information about source populations, and genetic and morphological samples at different time points along the invasion trajectory that can be used to investigate preadaptation and evolution during the invasion process, including immediately after introduction and before invasive expansion. For all three data sources, we explore where the data are held, their quality, and their accessibility. We argue that these sources could find widespread use with a few additional pieces of data, such as voucher specimens collected at certain critical time points during biocontrol agent quarantine, rearing, and release and also for horticultural imports, neither of which are currently done consistently. In addition, public access to collected information must become available on centralized databases to increase its utility in ecological and evolutionary research. [source] Biogeography of common dolphins (genus Delphinus) in the Southwestern Atlantic OceanMAMMAL REVIEW, Issue 1 2010Maurício TAVARES ABSTRACT 1The common dolphins (genus Delphinus) have one of most problematic taxonomies and complex distribution patterns of all cetaceans. Although the taxonomy and the distribution seem to have been clarified somewhat in the eastern North Pacific and Indo-Pacific Oceans, many questions remain in the Southwestern Atlantic Ocean (SWA). We review the biogeography of Delphinus in the SWA. 2We reviewed data from strandings, incidental catches and sightings since 1922. Systematic surveys were conducted in five major areas. Twenty-one natural history collections were examined, and 135 skulls were measured. 3A total of 184 records of common dolphins were compiled. Delphinus apparently occurs in three stocks in the SWA: one located in northern Brazil and two from southeastern Brazil (,22°S) to central Argentina (,42°S). Two distinct patterns in habitat use were observed by depth: in southeastern Brazil, sightings were restricted to coastal waters with water depths ranging from 18m to 70m. On the other hand, in the area that extends from southern Brazil to Central Argentina (from 28°S to 42°S), sightings were recorded in deeper waters, ranging from 71m to 1435m, with the exception of occasional coastal sightings. The cranial analyses demonstrated that both short-beaked common dolphins Delphinus delphis and long-beaked common dolphins Dephinus capensis occur in the SWA. 4In the SWA, Delphinus seems to occur near areas of high productivity. One stock is associated with the productive waters discharged by the Amazon River and possibily with the coastal upwelling system off the coast of Venezuela, while the other stocks are associated with the Cabo Frio upwelling system and the Subtropical Convergence. Our results indicate that the current taxonomy does not adequately reflect the amount of variation within the genus in the world. [source] D.E.Z. , A history.MITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE IN BERLIN-DEUTSCHE ENTOMOLOGISCHE ZEITSCHRIFT, Issue 2 2007150 years of scientific publishing in entomology The article sketches the 150 year long history of the Deutsche Entomologische Zeitschrift from its foundation in 1857 as Berliner Entomologische Zeitschrift by Ernst Gustav Kraatz. It gives insight into the struggle for defining good taxonomic practice in those early days and the founder's rather modern philosophy towards the purpose of natural history collections. A chronological table featuring the most important events is provided as well as historic photographs of the journal's founder and other long-time editors. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Distribution of the anther-smut pathogen Microbotryum on species of the CaryophyllaceaeNEW PHYTOLOGIST, Issue 1 2010Michael E. Hood Summary ,Understanding disease distributions is of fundamental and applied importance, yet few studies benefit from integrating broad sampling with ecological and phylogenetic data. Here, anther-smut disease, caused by the fungus Microbotryum, was assessed using herbarium specimens of Silene and allied genera of the Caryophyllaceae. ,A total of 42 000 herbarium specimens were examined, and plant geographical distributions and morphological and life history characteristics were tested as correlates of disease occurrence. Phylogenetic comparative methods were used to determine the association between disease and plant life-span. ,Disease was found on 391 herbarium specimens from 114 species and all continents with native Silene. Anther smut occurred exclusively on perennial plants, consistent with the pathogen requiring living hosts to overwinter. The disease was estimated to occur in 80% of perennial species of Silene and allied genera. The correlation between plant life-span and disease was highly significant while controlling for the plant phylogeny, but the disease was not correlated with differences in floral morphology. ,Using resources available in natural history collections, this study illustrates how disease distribution can be determined, not by restriction to a clade of susceptible hosts or to a limited geographical region, but by association with host life-span, a trait that has undergone frequent evolutionary transitions. [source] Combining geometric morphometrics and pattern recognition to identify interspecific patterns of skull variation: case study in sympatric Argentinian species of the genus Calomys (Rodentia: Cricetidae: Sigmodontinae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2008PEDRO CORDEIRO-ESTRELA Sympatric species of vesper mice Calomys laucha and Calomys musculinus are difficult to discriminate, especially in natural history collections where they are identified by external body measurements and cranial characteristics. Accurate identification of these two species can be important because only one of them, C. musculinus, is a Junin virus reservoir, the aetiological agent of the Argentine Hemorragic Fever. Research has focused into the development of molecular techniques to unambiguously identify these species. We apply statistical procedures from the field of pattern recognition to three-dimensional geometric morphometric data based on skull landmarks to identify sympatric species C. laucha, C. musculinus and Calomys venustus. Pattern recognition techniques correctly identified the three species without any prior information on specimen identity. By contrast to expectations, C. venustus differed from the other two species mainly on the basis of shape and not by its centroid size. The main sources of difference between C. laucha and C. musculinus were of shape, specifically localized at the landmarks defined by: (1) the sutures between the premaxillaries, the nasals and the frontals; (2) the sutures between the parietals, the frontals and the squamosals; and (3) the suture between the parietals and the interparietal. Nevertheless, allometries dominate the patterns of interspecific variation between these latter species and may partly explain past identification difficulties. Morphological evolution is discussed. The need for objective methods to define phenotypic clusters is highlighted with respect to the need for fast and precise biodiversity assessments. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94, 365,378. [source] | ||||||||||