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We have estimated levels of genetic diversity and partitioning in the Mexican endemic cycad species Dioon sonorense, Dioon tomasellii, and Dioon holmgrenii, whose populations are exclusively distributed along the Pacific seaboard. For the three species, the patterns of variation at 19 allozyme loci in a total of 11 populations were evaluated. The average number of alleles per locus was in the range 2.05–1.68, corresponding to the northernmost population of D. sonorense (Mazatán), and the southernmost population of Dioon holmgrenii (Loxicha), respectively. In turn, the percentage of polymorphic loci peaked (94.73) in the El Higueral and Altamirano populations of Dioon tomasellii, and was estimated to be lowest (57.89) in the Loxicha population of D. holmgrenii. The mean expected heterozygosis varied markedly between taxa, with relatively high indices for D. sonorense and D. tomasellii (HE = 0.314 and 0.295, respectively) and substantially lower values for D. holmgrenii (HE = 0.170). Comparison of the inferred genetic structure based on F‐statistics for the three species also indicated differences along the north‐south Pacific seaboard axis. For D. sonorense and D. tomasellii, local inbreeding (FIS) was zero but global inbreeding (FIT) values were positive and significantly different from zero (0.130 and 0.116, respectively). By contrast, values of both FIT and FIS were negative and significantly different from zero (?0.116 and ?0.201, respectively) for D. holmgrenii. The genetic differentiation between populations (FST) had positive values in all taxa and corresponded with their geographic location along the north‐south axis: according to this statistic, D. sonorense was the most differentiated species (FST = 0.151), D. tomasellii had intermediate values (FST = 0.145), and D. holmgrenii was the less differentiated taxon (FST = 0.069). Finally, a phenogram representing Nei's genetic distances among populations displayed three major groups, each one corresponding to each of the studied species. Within D. tomasellii (of intermediate geographic distribution), a further division into two clusters corresponded precisely to the pair of populations that are geographically divided by the Trans Mexican Neovolcanic Mountains. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94 , 765–776.  相似文献   
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Natural infection of wild mammals by protozoa parasites is quite common in nature. For Neotropical Primates different infections of parasites that are etiological agent of disease in human have been identified. In particular, infections by Trypanosoma cruzi and Leishmania sp., have been reported for some New World primate species, but there are no reports of infection with these parasites in any primate species in Mexico. A serological study was conducted on two howler monkey species (Alouatta pigra and A. palliata) from the Mexican states of Campeche and Tabasco. A total of 55 serum samples (20 samples from A. pigra, 20 samples from A. palliata, and 15 samples from semifree ranging A. palliata of Los Tuxtlas, Veracruz as negative controls) were analyzed for the detection of immunoglobulin G antibodies against T. cruzi and Leishmania mexicana through enzyme linked immunosorbent assay test, indirect immunofluorescence assay and Western blot. The overall prevalence of antibodies in howler monkeys was 17.5% for T. cruzi and 30% for L. mexicana. Our results also indicate that A. pigra is more susceptible to develop leishmaniasis than A. palliata. Finally, the finding of positive serology in these primates should be given serious consideration for public health, given the potential role of these primate species as wild reservoirs for these diseases and the increasing contact of monkeys with human populations due to habitat loss and fragmentation. Am. J. Primatol. 75:161‐169, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   
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The correct identity of three chromodorid nudibranch species,Chromodoris clenchi, C. neona and C. binza is established onthe basis of material from the Caribbean Sea. These three speciesare compared with C. britoi, from the northeastern Atlanticand the Mediterranean Sea. All four species have a colour patternof cream with red (or yellow) lines and blue spots. (Received 30 March 1993; accepted 20 November 1993)  相似文献   
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Histamine, the result of histidine decarboxylation, has been associated with allergic reactions due to the consumption of certain foods. Other biogenic amines, such as putrescine and cadaverine, have been related to quality deterioration in foods. A quantitative miniaturized method for the detection of biogenic amines produced by microorganisms in culture media, was designed. The reaction takes place in microplates containing microquantities of inoculated media and reagents. Amine production is determined spectrophotometrically by monitoring changes in the acid phase of the pH indicator at 405 nm. Using the following amino acids: histidine, phenylalanine, tyrosine, tryptophan, arginine, lysine and ornithine, 44 microorganisms were tested for amine production. Sensitivity of the method is 10 μM of amine.  相似文献   
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A new species, based on two specimens from Guana Island, BritishVirgin Islands, is described. The new species agrees with thegenus Hypselodoris in having a high body profile, a large vestibulargland and mantle glands. It differs from other members of thegenus in the Atlantic Ocean by having a reddish background bodycolour. In addition, dorsal colour patterns such as a broadcentral white line with lateral extensions and the lack of yellowlines or spots further differentiate this species. The radularformula of 52x41.0.41 and a smaller seminal receptacle are alsodistinctive. The phylogenetic relationships of 34 species andsubspecies of Hypselodoris from the eastern Pacific and Atlanticare examined using morphological characters. With the exceptionof the new species, these are characterized by a dark blue backgroundbody colour. The phylogenetic analysis of the data matrix resultedin eight most-parsimonious trees. The resulting consensus treeshows that eastern Pacific and Atlantic species of Hypselodorisconstitute a monophyletic group that is basally split into twosister clades. One clade contains the eastern Pacific speciesand most of the Caribbean species, whereas the other clade containsthe eastern Atlantic species. The new species is the sisterto the rest of the Caribbean species, which also form a monophyleticgroup. This phylogenetic hypothesis suggests that two consecutivevicariant events have affected the biogeography of Hypselodoris:(1) the closure of communication between the tropical Indo-Pacificregion and the Atlantic and eastern Pacific, completed withthe formation of the East Pacific Barrier; and (2) the riseof the Panama isthmus. (Received 19 December 2003; accepted 12 October 2005)  相似文献   
49.
Six valid species of the nudibranch genus Dendrodons Ehrenberg,1831 inhabit the Atlantic Ocean, including the Mediterraneanand Caribbean Seas. Dendrodons lumbata (Cuvier, 1804), Dendrodonsgrandiflora (Rapp, 1827), Dendrodons nigra (Stimpson, 1855)(immigrant from the Red Sea), Dendrodons krebsu (Mörch,1863), Dendrodoru senegalensis Bouchet, 1975 and Dendrodonswarta Marcus & Gallagher, 1976. Additional data about thebiology and geographical distribution of these species are presented.New evidence suggests that other species assigned to the genusDendrodons, Dendrodons racemosa Pruvot-Fol, 1951 and Dendrodonsminima Pruvot-Fol, 1951, must be included in the genus DoriopsillaBergh, 1880. Three new species of Dendrodoris are describedfrom the Northeastern Atlantic and West Africa;Dendrodons angolensis,Dendrodoris guineana and Dendrodons herytra. The variable external morphology makes species recognition difficult.Instead, the diagnostic characters utilised to separate speciesare the shape of the male cirrus hooks, the structure of thereproductive system and features of the egg-mass. (Received 25 April 1995; accepted 1 August 1995)  相似文献   
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Book Reviews     
Book reviewed in this article:
PHYSICAL ANTHROPOLOGY: Primatologia. Handbook of Primatology . H. HOFER, A. H. SCHULTZ, D. STARCK
PHYSICAL ANTHROPOLOGY: Volarhaut der Hände und Füsse . JOSEF BIEGERT. Primatologia
PHYSICAL ANTHROPOLOGY: Das Ohr
PHYSICAL ANTHROPOLOGY: Pattern of the Cerebral Isocortex . GERHARDT VON BONIN and PERCIVAL BAILEY
PHYSICAL ANTHROPOLOGY: Vertebral Column and Thorax . ADOLPH H. SCHULTZ  相似文献   
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