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1.
Agave manantlanicola, a new endemic species from the high altitude mountains of the Sierra de Manantlán in western Mexico, is described and illustrated. The species belongs to the subgenus Littaea and Gentry’s Amolae group. The new species is compared to other morphologically similar species from western Mexico, including Agave attenuata subsp. attenuata, A. attenuata subsp. dentata, A. bakeri, A. chazaroi, and A. vazquezgarciae. Information about its distribution, habitat, and conservation status is included. 相似文献
2.
Susan Verhoek 《Brittonia》1978,30(2):165-171
Two new species ofManfreda are named,M. longibracteata from Michoacán, Mexico, andM. sileri, a succulent-leaved species from the Rio Grande Valley of Texas and Mexico.Agave hauniensis is transferred toManfreda. 相似文献
3.
D. V. Antonenko A. A. Balanov I. I. Glebov V. V. Yamshchikov 《Journal of Ichthyology》2012,52(8):492-504
Based on materials of bottom inventory trawl survey performed in summer 2008 in the western part of the Bering Sea, we show that representatives of the genus Lycodes in the summer period occur almost throughout the study water area of the sea from the sublittoral to the drop-off. The pattern of distribution and abundance of particular species depend on the depth and specific features of the hydrological regime of the given area. The most numerous species??Lycodes brevipes and L. palearis??are found in warm intermediate and in cold demersal water masses, are distributed over a vast stretch, and there form considerable concentrations. Deep-water species??L. beringi and L. concolor??are more stenothermal, occur along the narrow band of the continental slope, and are considerably inferior to stretch species in numbers. Of shallow species dwelling at depths smaller than 100 m, only L. raridens has high numbers and occurs over a considerable area in the northern part of the study area, the remaining species (L. mucosus, L. polaris, and L. turneri) are caught in small amounts at local sites. The largest sizes are in L. raridens and L. concolor, their maximum length in catches is more than 70 cm, the former species reaches maximum length in the seventh year of life, and the latter reaches maximum length in the ninth year. The smallest and slowest-growing among the studied fish is L. brevipes: its maximum length in catches does not exceed 39 cm and maximum age is 7 years. 相似文献
4.
Aphidius staryi Chen & Luhman n. sp. is described. The species was collected and introduced into California from Israel and Turkey byD. González. The new species is morphologically most similar toAphidius smithi, and keys toEady's urticae group. 相似文献
5.
A new species of Mimosa section Mimosa, Mimosa eurystegia, which is apparently endemic to Paraná in southern Brazil, is described and illustrated. This species is distinguished by plurinerved leaflets and papyraceous, plurinerved, orbicular, amplexicaul stipules. Morphological distinctiveness of this new Mimosa and its relationships with allied species are discussed. Phenological, geographical and ecological data are presented, in addition to a key to the species of Mimosa subser. Sparsae. 相似文献
6.
Jon Kastendiek 《Journal of experimental marine biology and ecology》1982,62(3):201-210
Manipulative field experiments were used to determine the mechanism of coexistence of three species of benthic macro-algae (Eisenia arborea Areschong, Halidrys dioica Gardner, and Pterocladiacapillacea (Gmelin)) which occur in a narrow band of substratum from 0.3 to 2.3 m below MLLW on Santa Catalina Island, California. Eisenia forms a canopy and excludes Halidrys from areas beneath this canopy. Pterocladia occurs in the space beneath the Eisenia canopy. Upon canopy removal, Halidrys grows adventitiously, excludes Pterocladia, and preempts all space on the substratum. However, Pterocladia is not physiologically restricted to being an understory plant. When the canopy is removed and Halidrys is prevented from entering the area, Pterocladia flourishes. Pterocladia persists in the community because of its ability to utilize the refuge from its superior competitor, Halidrys, afforded by the Eisenia canopy. Eisenia, the competitive dominant to Halidrys, therefore, mediates the coexistence of Halidrys and its inferior competitor Pterocladia in a manner similar to the role that predators and physical disturbance play in other marine communities. 相似文献
7.
8.
P.C. Silva
F.F. Pedroche
M.E. Chacana
L.E. Aguilar Rosas L.E. Aguilar Rosas 《Journal of phycology》2000,36(Z3):63-63
Silvetia compressa ( J. Agardh) Serrão et al. is a common member of the upper intertidal fucoid community on the Pacific coast of America from Humboldt County, California, to Punta Baja, Baja California, Mexico. A relatively narrow range of morphological variability is exhibited by most mainland populations, regardless of latitude, but some mainland populations and all insular populations participate in a complex pattern that we have attempted to analyze. A few populations on the Monterey Peninsula in which the fronds are atypically delicate were described by Setchell & Gardner as f. gracilis, to which was assigned a population from Santa Catalina Island. After comparing populations from various parts of the range of the species, including all of the Channel Islands, we conclude that two subspecies may be recognized. In subsp. compressa, which includes f. gracilis as a growth form and occurs chiefly on the mainland, the frond is robust with long tapered receptacles. In the variant subspecies, which is chiefly insular but also occurs on the coast of northern Baja California, the typical frond has slender axes as in f. gracilis, but is more densely branched and has short ellipsoidal receptacles. Comparison of nucleotide sequences from the ITS regions of rDNA revealed an identical pattern for subsp. compressa from Baja California and central California, including populations assignable to f. gracilis. By contrast, the pattern for the variant subspecies differed by 2 bp (0.3%) from that of subsp. compressa. 相似文献
9.
Tomáš Přikryl 《Pal?ontologische Zeitschrift》2014,88(2):187-196
A new species of gobioid fish Pirskenius Obrhelová, 1961 (P. radoni sp. nov.) is described from Oligocene strata of the ?eské St?edoho?í Mountains and compared with related species. The new species is characterized by a unique combination of characters that allow it to be separated from P. diatomaceus Obrhelová, 1961. The taxonomic position of the genus Pirskenius is discussed, and its affinity to the family Eleotridae is indicated. The new record documents, together with P. diatomaceus, the oldest known skeletal record of the Eleotridae. 相似文献
10.
Recent fieldwork in central Arizona resulted in the discovery of two agaves that display low seed set, reproduce mainly by vegetative means, have restricted distributions, and cannot be readily assigned to any existing species. These agaves are closely associated with archaeological structures and features and can be found growing with other previously described pre-Columbian Agave domesticates. Herein we describe Agave verdensis and A. yavapaiensis, two species that can be placed within Gentry’s informal Ditepalae Agave group, and propose that they are clonal relict domesticates. The two species have affinities with A. chrysantha, A. shrevei, and A. delamateri, the latter also a central Arizona pre-Columbian domesticate. We provide a key to distinguish these species from other agaves in central Arizona and adjacent northern Mexico with which they may be confused. The discovery of these two new species brings the total number of putative Arizona Agave domesticates to five species. 相似文献
11.
Gary C. Williams 《ZooKeys》2013,(283):15-42
A taxonomic assessment of four species of octocorals from the northeastern Pacific Ocean (British Columbia to California) is provided. Included here are a new species of clavulariid stolonifieran Cryptophyton, a new species of the nephtheid soft coral Gersemia, an undetermined species of soft coral in the genus Alcyonium that has been referred in the literature by several other names, and a new genus is named for a plexaurid sea fan originally described in the Indo-Pacific genus Euplexaura. Discussions are included that compare the species to related taxa, or provide revisionary assessments. 相似文献
12.
Three of the five known species ofLepidopus occur in the eastern Pacific.Lepidopus manis sp. nov. is described from a single specimen from the Galápagos Islands. The holotype ofL. xantusi Goode et Bean, 1895, supposedly from Cape San Lucas, Lower California, is shown to be conspecific withL. caudatus (Euphrasen, 1788). The species heretofore reported under the nameL. xantusi is described, and namedL. fitchi sp. nov. It ranges from Oregon to the Gulf of California and occurs disjunctly in southern Ecuador and northern Peru. A key to the described species ofLepidopus is given and certain morphological features ofL. caudatus are described. Geographic variability ofL. caudatus andL. fitchi is discussed. 相似文献
13.
G. Ansley Wallace 《Brittonia》1979,31(3):416-421
Smilax jamesii, a new species from northern California is described and illustrated. Its distribution and its distinction from the other species of the area, 5.californica (A. DC.) A. Gray, are discussed, as is its relationship to the other species of the sectionCoprosmanthus. 相似文献
14.
Mary H. Straub Terra R. Kelly Bruce A. Rideout Curtis Eng Janna Wynne Josephine Braun Christine K. Johnson 《PloS one》2015,10(11)
Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats. 相似文献
15.
María Fernanda Cárdenas Conrado Tobón Barret N. Rock Jorge Ignacio del Valle 《Plant Ecology》2018,219(2):185-198
Páramos are high elevation tropical ecosystems in northern Andes, with large water yield and water regulation. One of the main and representative species growing in these páramos is the genus Espeletia, known as frailejones. There is a lack of knowledge of Espeletia ecophysiology, maybe due to its unusual anatomical modifications and the specific climatic conditions of these ecosystems. Therefore, it is important to determine the relationships between the anatomical modifications of Espeletia, its physiological functioning, and its contribution to the ecohydrologic functioning of páramos. Consequently, we studied the physiology of frailejones in two Colombian páramos, focused on the identification of conductive tissues inside the stems, calculated the age, and measured sapflow, using the heat ratio method. Results show that Espeletia spp. have a central pith that increases with height, as the size of secondary xylem decreases. Frailejones respond quickly to the changing conditions of weather factors controlling transpiration such as solar radiation, temperature, and fog presence. However, although environmental factors favor transpiration, the sapflow tends to decrease—a particular behavior of the Espeletia transpiration processes—since this occurs chaotically over time, including sapflow at night. The transformation of sapflow velocity to depth of water in a basin shows that the water lost through their transpiration is very low, which contributes to the high runoff ratio of páramo ecosystems. For the first time, we determine by radiocarbon the real ages of three E. hartwegiana, and their mean growth rates to range between 3.8 and 6.9 cm year?1. 相似文献
16.
Flávio C.T. Lima Míriam P. Albrecht Carla S. Pavanelli Volney Vono 《Environmental Biology of Fishes》2008,83(2):207-208
Brycon nattereri (Ostariophysi: Characiformes: Characidae), a threatened South American freshwater fish, occurs in the Paraná, Tocantins and São Francisco river basins in central Brazil. It is a middle-sized (up to 50 cm SL), omnivorous species, which occurs in swift, clear-water rivers with well-preserved riparian vegetation. Main threats to the species are water pollution, dam building, and deforestation. 相似文献
17.
Shawn R. Kuchta Duncan S. Parks David B. Wake 《Molecular phylogenetics and evolution》2009,50(2):240-255
The salamander Ensatina eschscholtzii is a classic example of a ring species, and has an intricate biogeographic history. Within a part of the ring distribution, earlier work using allozymes disclosed high levels of genetic structure in central coastal California, where the subspecies oregonensis, xanthoptica, and eschscholtzii meet. We used mitochondrial cytochrome b sequences to further examine patterns of divergence in this area, including data from 155 localities (309 individuals). Our focus is on the documentation of population-level haplotype lineages. We show that oregonensis is represented by two unrelated, phenotypically similar clades, both of which possess substantial substructure of their own. The subspecies xanthoptica includes two lineages that differ in phenotype, one of which has colonized the foothills of the Sierra Nevada. The subspecies eschscholtzii occurs mainly to the south, but some populations from a northern lineage extend into the Monterey Bay region, where they approach xanthoptica geographically. In sum, populations in the central coastal California region form a distributional patchwork, including three subspecies, three clades (which differ from the three subspecies), and ten haplotype lineages. We conclude that such striking levels of phylogeographic structure reflect interspersed episodes of spatial fragmentation, in part driven by the complex geomorphological evolution of the California Coast Range system. 相似文献
18.
Rupert C. Barneby 《Brittonia》1986,38(1):4-8
TheMimosa of trans-Pecos Texas passing latterly asM. zygophylla Benth. is described as a new species.M. turneri Barneby. Its relationships to vicariantM. borealis A. Gray and to the gypsophileM. unipinnata Parf. & Pink. are thought to be closer than toM. zygophylla. Significant differences between these four species are discussed and summarized in a key, and the known range of each is mapped. 相似文献
19.
Stelis duckei, of the Crocodeilanthe group, is described from the state of Ceará, Brazil. The new species is morphologically similar to S. speciosa, but can be distinguished by its longer ramicauls, wider leaves, and obtuse lip with a ridge-like callus at the base. The new combination Stelis speciosa is also provided here. 相似文献
20.
W. Frederick Hinton 《Brittonia》1975,27(3):197-208
TheCalyptridium umbellatum complex (Portulacaceae), which has been treated as including from one to nine species, is shown to comprise three morphologically distinctive species. Two of these are common, wide-ranging, montane perennial herbs—C. umbellatum, which occurs over a large part of western North America, andC. monospermum, which largely replacesC. umbellatum in cismontane California. The third member of the complex is the rare or possibly extinctC. pulchellum. The perennial members of this complex are accorded the status of a separate genus,Spraguea, by most authors, but a comparative study of the morphology and karyology of all species ofCalyptridium shows this separation to be unwarranted. Chromosome numbers ofn = 22, obtained from eight populations ofC. umbellatum and six ofC. monospermum, constitute the first reported counts for these species. Hybridization studies involvingC. umbellatum andC. monospermum indicate that they are isolated by an incomplete noncrossability barrier. 相似文献