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Published Descriptions (published + description)
Selected AbstractsEarly differentiation and migration of cranial neural crest in the opossum, Monodelphis domesticaEVOLUTION AND DEVELOPMENT, Issue 2 2003Janet L. Vaglia SUMMARY Marsupial mammals are born at a highly altricial state. Nonetheless, the neonate must be capable of considerable functional independence. Comparative studies have shown that in marsupials the morphogenesis of many structures critical to independent function are advanced relative to overall development. Many skeletal and muscular elements in the facial region show particular heterochrony. Because neural crest cells are crucial to forming and patterning much of the face, this study investigates whether the timing of cranial neural crest differentiation is also advanced. Histology and scanning electron microscopy of Monodelphis domestica embryos show that many aspects of cranial neural crest differentiation and migration are conserved in marsupials. For example, as in other vertebrates, cranial neural crest differentiates at the neural ectoderm/epidermal boundary and migrates as three major streams. However, when compared with other vertebrates, a number of timing differences exist. The onset of cranial neural crest migration is early relative to both neural tube development and somite formation in Monodelphis. First arch neural crest cell migration is particularly advanced and begins before any somites appear or regional differentiation exists in the neural tube. Our study provides the first published description of cranial neural crest differentiation and migration in marsupials and offers insight into how shifts in early developmental processes can lead to morphological change. [source] A new case of intralacustrine radiation in Amphipoda.JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 2 2009A new genus, Amphipoda) from the ancient lake Fuxian Hu in Yunnan, China, three new species of Anisogammaridae (Crustacea Abstract Fuxian Hu is a deep freshwater lake in the high plateau in Yunnan Province, China. After a study and description of Fuxiana yangi Sket, 2000 from deep waters, some coastal samples of amphipods were taxonomically evaluated. Four species were recognized, which in winter co-occur along most of the shallow littoral zone around the lake; they were identified as members of the family Anisogammaridae. One species was recognized as a slightly differentiated Eurypodogammarus helobius Hou et al., 2005, and the others as new species of Fuxigammarus gen. n. Results of a cladistic analysis performed on morphological characters from published descriptions, which included all lacustrine taxa and representatives of all other anisogammarid genera, established the monophyly of the new genus. Endemic character and monophyly of the group testify to an intralacustrine radiation within Fuxigammarus. Fuxian Hu is the fifth known lake in the world to contain a radiation of amphipods and is the only one inhabited by members of Anisogammaridae. Fuxigammarus gen. n. is characterized by a small and slender body, scant dorsal setosity-spinosity, and single, sausage-shaped accessory lobes on coxal gills, antennae without calceoli and rod shaped uropod III. These species differ substantially from each other by characters that do not occur in other anisogammarid genera. The type species F. antespinosus sp. nov. has spiniform dorsal setae shifted forward. Fuxigammarus barbatus sp. nov. has extremely setose antennal bases and mandibular palps and an elongated proximal flagellar article of antenna II. Fuxigammarus cornutus sp. nov. has a pair of dorsal spiniform setae only on humped urosomite I and the usually spiniform setae replaced by flexible setae on the telson. These characters are a kind of counterpart to the specific body armature of the Bajkal amphipods. Zusammenfassung Fuxian Hu ist ein tiefer Süßwassersee auf dem Hochplateau der Yunnan-Provinz in China. Nach der Beschreibung von Fuxiana yangi Sket, 2000 aus den Tiefen des Sees wurden auch Amphipoden-Proben aus dem Litoralbereich taxonomisch ausgewertet. Vier Arten wurden erkannt, die im Winter gemeinsam das flache Litoral rund um den See bewohnen. Sie wurden der Familie Anisogammaridae zugeordnet. Eine der Arten konnte als leicht differenzierte Eurypodogammarus helobius Hou et al., 2005 bestimmt werden, während die anderen als neue Arten einer neuen Gattung, Fuxigammarus gen.nov., beschrieben werden. Die Monophylie der neuen Gattung wurde durch eine phylogenetische Analyse bestätigt, die alle im See bekannten Arten sowie Vertreter aller anderen Anisogammariden-Gattungen mit einbezog. Der Endemismus und die Monophylie der Gattung deuten auf eine intralakustrische Radiation von Fuxigammarus. Somit ist Fuxian Hu der fünfte See weltweit, in dem eine Radiation von Amphipoden nachgewiesen wurde, und der einzige davon mit Anisogammariden. Fuxigammarus gen. n. besitzt einen kleinen und schlanken Körper, eine arme Dorsalbestachelung, nur je eine Nebenast auf jeder Coxalkieme, Antennen ohne Calceoli und stabförmige Uropoden III. Sie unterscheiden sich deutlich in Merkmalen, die bei anderen Anisogammariden nicht vorkommen. Die Typusart F. antespinosus sp. nov. besitzt nach vorne verdrängte Dorsal-Stacheln. Fuxigammarus barbatus sp. nov. hat dicht setose Antennenenbasen und Mandibularpalpen sowie ein verlängertes proximales Glied im Flagellum der Antenne II. Fuxigammarus cornutus sp. nov. besitzt nur ein Paar stachelförmige Dorsal-Setae auf dem gewölbtem Urosomit I, und weiche anstatt der sonst normalen stachelförmigen Setae auf dem Telson. Diese Merkmale wirken wie ein Gegenstück zu den spezifischen Schutzstrukturen der Baikal-Amphipoden. [source] A review of the comparative morphology and systematics of Utah Lake suckers (Catostomidae)JOURNAL OF ZOOLOGY, Issue 3 2001A. Gaylon Cook Abstract Utah Lake, Utah, U.S.A. harbours an endemic catostomid fish, the June sucker Chasmistes liorus, that is recognized as being endangered. Since 1981, post-1935 representatives of the June sucker have generally been considered to be examples of a self-propagating hybrid. Utah Lake has contained another endemic catostomid, the webug sucker Chasmistes fecundus that was regarded as a true species until 1981 when it was judged to be an extirpated sterile hybrid. Since then, fisheries biologists have not attempted to identify it. This review makes a comparative examination of the published descriptions of the internal and external anatomy of these two species, plus the third catostomid of Utah Lake, the Utah sucker Catostomus ardens. The Utah sucker purportedly crossed with a form of the June sucker that has supposedly since been expunged, to produce hybrids. On the basis of comparative morphology and the consideration of temporal changes in the habitat and piscifauna of Utah Lake, the authenticity of supposed hybridism in the webug sucker, and in the contemporary June sucker, is analysed. The conclusion is reached that there is insufficient evidence to deem these taxa hybrids, or the webug sucker, extinct. [source] Overlap between neurodegenerative disordersNEUROPATHOLOGY, Issue 2 2005Richard A. Armstrong Neurodegenerative disorders are characterized by the formation of distinct pathological changes in the brain, including extracellular protein deposits, cellular inclusions, and changes in cell morphology. Since the earliest published descriptions of these disorders, diagnosis has been based on clinicopathological features, namely, the coexistence of a specific clinical profile together with the presence or absence of particular types of lesion. In addition, the molecular profile of lesions has become an increasingly important feature both in the diagnosis of existing disorders and in the description of new disease entities. Recent studies, however, have reported considerable overlap between the clinicopathological features of many disorders leading to difficulties in the diagnosis of individual cases and to calls for a new classification of neurodegenerative disease. This article discusses: (i) the nature and degree of the overlap between different neurodegenerative disorders and includes a discussion of Alzheimer's disease, dementia with Lewy bodies, the fronto-temporal dementias, and prion disease; (ii) the factors that contribute to disease overlap, including historical factors, the presence of disease heterogeneity, age-related changes, the problem of apolipoprotein genotype, and the co-occurrence of common diseases; and (iii) whether the current nosological status of disorders should be reconsidered. [source] Hydroclathrus (Scytosiphonaceae, Phaeophyceae): Conspectus of the genus and proposal of new species from Australia and HawaiiPHYCOLOGICAL RESEARCH, Issue 4 2003Gerald T. Kraft SUMMARY Representatives of the two current species of Hydroclathrus, Hydroclathrus clathratus (C. Agardh) Howe (the generitype) and Hydroclathrus tenuis Tseng et Lu, are compared to recent collections of the genus from isolated localities in the central and south Pacific: Necker Island and Lord Howe Island, respectively. Although published descriptions of the virtually pan-tropical/warm-temperate H. clathratus portray a species highly variable in the habits and soral distribution patterns of the macro-phases of its life history, our observations support the hypothesis that the newly discovered Pacific island populations represent new species. Hydroclathrus steph-anosorus Kraft, sp. nov., from Lord Howe Island, differs from seemingly typical H. clathratus by the low-domed profiles of its surface cortical cells, aggregates of moniliform hair primordia that are almost always associated with plurangial sori, and particularly by the configurations of the sori themselves, which form discrete, nearly circular rings around the central hair tufts. Hydroclathrus tumulis Kraft et Abbott, sp. nov., from two deep-water localities in the northwestern Hawaiian Islands, has subacutely papillate cortical cells, scattered single, paired or laxly aggregated hair primordia of distinctive obcuneate morphology, and discrete, angular plurangial sori with no predetermined relationship to hairs, the plurangia being relatively laxly aggregated by virtue of their often arising on pedicels formed by the peaked crests of the cortical bearing cells. H. tenuis, although making the most striking visual impression of any of the species because of its exceedingly narrow, fibrous membranes, seems otherwise closest to H. clathratus in cortical cell, hair and soral features, absolute morphological boundaries between the two species being perhaps difficult to draw at times. [source] The North American cranberry fruit rot fungal community: a systematic overview using morphological and phylogenetic affinitiesPLANT PATHOLOGY, Issue 6 2009J. J. Polashock Cranberry fruit rot (CFR) is caused by many species of fungi, with the contribution of any given species to the disease complex varying among plantings of Vaccinium macrocarpon within a site, sites within regions, and among regions and years. This study assessed the morphological and molecular variability of five widespread CFR-causing fungi: Phyllosticta vaccinii, Coleophoma empetri, Colletotrichum acutatum, Colletotrichum gloeosporioides and Physalospora vaccinii. Although the majority of isolates had morphological characteristics consistent with published descriptions, some were atypical. For example, non-chromogenic isolates of C. acutatum were recovered from British Columbia and white isolates of Physalospora vaccinii were recovered in addition to the more common dark isolates. On the basis of sequence analysis of the ITS and large subunit rDNA (LSU), it appears that Phyllosticta vaccinii, C. empetri, C. gloeosporioides and C. acutatum are genetically uniform on cranberry in North America. This suggests the possibility that these fungal species were introduced to cultivated cranberries and concomitantly moved with planting material to new locations. In contrast, white isolates of Physalospora had ITS and LSU sequences distinct from those of their dark counterparts, with phylogenetic analyses suggesting that these isolates represent either different species or distinct members of highly divergent populations. Taxonomic placement of all species based on phylogenetic relationships was consistent with morphological placement, with the exception of Physalospora vaccinii. Unlike other Physalospora species, CFR isolates of Physalospora vaccinii were not allied with the Xylariomycetidae; instead, these fungi were members of the Sordariomycetidae. A deeper taxonomic analysis is needed to resolve this inconsistency in familial affiliation. [source] | ||||||||||