首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
    
Uto-Aztecan premolar (UAP) is a rare morphological feature of the maxillary first premolar that occurs in Native American populations with frequencies ranging 0-16.7%. A recent summary of UAP by Delgado-Burbano et al. (2010) suggests the trait evolved around 4,000 BP in the American Southwest where the earliest cases occur and where the trait exists at the highest frequencies among contemporary populations. In this article, we present new data on UAP prevalence from an Archaic North American sample from Buckeye Knoll, Texas (circa 7,500-6,200 cal BP). Buckeye Knoll preserves a single case of UAP, and a sample frequency of 3.6%. In addition, we confirm the presence of UAP in other eastern North American Archaic skeletal samples from the Windover and Harris Creek at Tick Island sites in Florida. We also review the dental morphological literature to assess: 1) whether UAP prevalence is limited to New World populations, and 2) whether the trait's antiquity can be extended further into the Early Holocene Paleoindian period. Additional cases of UAP are presented from the Pacific coast of South America, Europe, Asia, and Australia. Combined, these data greatly expand the spatial and temporal distribution of UAP and suggest the trait evolved considerably earlier than previously thought.  相似文献   

2.
    
The Uto‐Aztecan premolar is a discrete dental trait found in low frequency (<2%) among world populations. The highest frequencies of the trait have been found among the indigenous populations of North America and, to a lesser extent, South America. Because of the trait's relatively higher frequency in the Western Hemisphere, the antiquity and distribution of the feather is important for reconstructing the biocultural interactions of prehistoric populations. While early research concluded that the Uto‐Aztecan premolar originated in the American Southwest around 4,000 years Before Present (BP), more recent studies have discovered the trait across the Americas and in parts of Europe and Asia. For this study, over 300 dentitions representing foragers and farmers in south‐central North America were examined. The trait was found in relatively high frequency (over 11%) in Archaic hunter‐gatherer populations from Central Texas, with high frequencies also found in the adjacent western Gulf Coastal Plain. The presence of this trait in Early Archaic populations suggests that the trait was present by 8,000 BP and persisted at a high frequency into the Late Archaic period. Am J Phys Anthropol 149:318–322, 2012. © 2012 Wiley Periodicals, Inc.  相似文献   

3.
4.
  总被引:2,自引:0,他引:2  
The distribution of tardigrades in the states of the southern United States is poorly known. There are no published records from the state of Louisiana, while in Arkansas only one species has been reported. Samples of mosses and lichens from trees and rocks were collected from three sites in central and southern Louisiana and six sites in western Arkansas. Leaf litter samples were collected from one site in Louisiana. Nine species of tardigrade were found in Louisiana and 22 in Arkansas. The number of species per sample ranged from one to six.  相似文献   

5.
    
Variation in tooth crown morphology plays a crucial role in species diagnoses, phylogenetic inference, and the reconstruction of the evolutionary history of the primate clade. While a growing number of studies have identified developmental mechanisms linked to tooth size and cusp patterning in mammalian crown morphology, it is unclear (1) to what degree these are applicable across primates and (2) which additional developmental mechanisms should be recognized as playing important roles in odontogenesis. From detailed observations of lower molar enamel–dentine junction morphology from taxa representing the major primate clades, we outline multiple phylogenetic and developmental components responsible for crown patterning, and formulate a tooth crown morphology framework for the holistic interpretation of primate crown morphology. We suggest that adopting this framework is crucial for the characterization of tooth morphology in studies of dental development, discrete trait analysis, and systematics.  相似文献   

6.
After examining syntypes of Onthophagus cervicornis Kirby, 1825, previously considered to be a synonym of the North American Onthophagus striatulus (Palisot de Beauvois, 1809), we confirm the true identity and new synonymy under South Asian Onthophagus dama (Fabricius, 1798).  相似文献   

7.
8.
The author comments on a recent article by Werner Cohn concerning the kinship terms among the North American Gypsies. He suggests that since pašo, meaning wife's sister's husband, is also found among the southern Slavs, it is highly probable that it is from them that the Gypsies took the term .  相似文献   

9.
Noel H. Holmgren 《Brittonia》1992,44(3):300-305
Viola lithion andV. franksmithii are rock-dwelling endemics that belong to the North American perennial, caulescent, simple-leaved, blue-, purple-, or white-flowered group of species.Viola lithion, from the White Pine and Pilot mountain ranges of eastern Nevada and adjacent Utah, belongs to sectionChamaemelanium subsectionCanadenses. It most closely resembles the reniform-leaved, Olympic MountainV. flettii, together with which it possibly shares an ancestry with the widespread and allopatricV. canadensis. Viola franksmithii, restricted to the Logan Canyon drainage of the Bear River Range in northern Utah, belongs to sectionRostellatae subsectionRosulantes. It comes closest morphologically toV. howellii of the Coast Range, but likely evolved from the widespreadV. adunca or a common ancestor.  相似文献   

10.
简介北美洲药用植物的总体情况,30种重要种类的产地、药用部位、活性成分、功效,以及常用种类的简要情况。  相似文献   

11.
    
  相似文献   

12.
    
The earliest euprimates to arrive in North America were larger‐bodied notharctids and smaller‐bodied omomyids. Through the Eocene, notharctids generally continued to increase in body size, whereas omomyids generally radiated within small‐ and increasingly mid‐sized niches in the middle Eocene. This study examines the influence of changing body size and diet on the evolution of the lower fourth premolar in Eocene euprimates. The P4 displays considerable morphological variability in these taxa. Despite the fact that most studies of primate dental morphology have focused on the molars, P4 can also provide important paleoecological insights. We analyzed the P4 from 177 euprimate specimens, representing 35 species (11 notharctids and 24 omomyids), in three time bins of approximately equal duration: early Wasatchian, late Wasatchian, and Bridgerian. Two‐dimensional surface landmarks were collected from lingual photographs, capturing important variation in cusp position and tooth shape. Disparity metrics were calculated and compared for the three time bins. In the early Eocene, notharctids have a more molarized P4 than omomyids. During the Bridgerian, expanding body size range of omomyids was accompanied by a significant increase in P4 disparity and convergent evolution of the semimolariform condition in the largest omomyines. P4 morphology relates to diet in early euprimates, although patterns vary between families. Am J Phys Anthropol 153:15–28, 2014. © 2013 Wiley Periodicals, Inc.  相似文献   

13.
14.
This paper considers shell-shape variation in samples of the dog-whelk/dog-winkle, ucella lapillus , from the southern half of its North American range, between 41 and 46N, and compares it with the pattern seen in Europe. At the extreme southern limit of its American range, to the south of Cape Cod, the species exhibits features to be expected in an animal close to an environmental limit. It is generally rare and has a patchy distribution. There is little variation in the shell: almost all adult individuals have rather large, thick, white, elongated shells. This contrasts sharply with the situation in Portugal, at the southern limit in Europe, where the animals have small thin, coloured shells of intermediate shape.
Away from the marginal situation, north of Nahant (42CN) in America, the species shows much the same range of variability in shell size, shape and colour on both sides of the Atlantic. Most populations appear to show the same pattern of shape variation in asociation with the exposure of their habitat to wave action. Animals from exposed sites tend to have shorter, squatter shells than their compatriots in shelter. However, in America as in some parts of Europe, there are occasional enclaves which do not fit the usual pattern. It is interesting to note that the form normally associated with extremely exposed shores from Brittany to Faroe in Europe is found in Atlantic Canada but is apparently absent from southern populations in both the U.S.A and the Iberian Peninsula.  相似文献   

15.
The following ten new species of the ant genus Temnothorax are described and illustrated: T. anaphalantus (California, Baja California), T. arboreus (California), T. caguatan (Oregon, California, Baja California), T. morongo (California, Baja California), T. myrmiciformis (California, Baja California), T. nuwuvi (Nevada), T. paiute (California, Nevada), T. pseudandrei (Arizona, California), T. quasimodo (California) and T. wardi (California). A key to workers of the twenty-two Temnothorax species known or expected to occur in California is provided.  相似文献   

16.
    
The North American (north of Mexico) species of the tenebrionid genus Paratenetus Spinola are reviewed and a key is presented for their identification. Five species are recognized, P. gibbipennis Motschulsky, P. fuscus LeConte, P. punctatus Spinola and two sp. n., P. exutus [type locality: Tabusintac, Nova Scotia] and P. texanus [type locality: Port Isabel, Cameron County, Texas]. Two syn. n. are proposed: P. cribratus Motschulsky, 1868 with P. gibbipennis Motschulsky, 1868 and P. crinitus Fall, 1907 with P. fuscus LeConte, 1850. A lectotype is selected for Paratenetus punctatus Spinola. A type species is designated for Storthephora Mäklin, 1875 (Storthephora denticollis Mäklin, 1875).  相似文献   

17.
A Type II tooth cusp occurrence asymmetry proposed for human twins in 1974 but not observed until recently was described in a female monozygotic twin pair. Am J Phys Anthropol 105:93–95, 1998. © 1998 Wiley-Liss, Inc.  相似文献   

18.
    
The dynamics of Dinophysis acuminata and its associated diarrhetic shellfish poisoning (DSP) toxins, okadaic acid (OA) and dinophysistoxin-1 (DTX1) as well as pectenotoxins (PTXs), were investigated within plankton and shellfish in Northport Bay, NY, USA, over a four year period (2008–2011). Over the course of the study, Dinophysis bloom densities ranged from ~104 to 106 cells L−1 and exceeded 106 L−1 in 2011 when levels of total OA, total DTX1, and PTX in the water column were 188, 86, and 2900 pg mL−1, respectively, with the majority of the DSP toxins present as esters. These cell densities exceed – by two orders of magnitude – those previously reported within thousands of samples collected from NY waters from 1971 to 1986. The bloom species was positively identified as D. acuminata via scanning electron microscopy and genetic sequencing (cox1 gene). The cox1 gene sequence from the D. acuminata populations in Northport Bay was 100% identical to D. acuminata from Narragansett Bay, RI, USA and formed a strongly supported phylogenetic cluster (posterior probability = 1) that included D. acuminata and Dinophysis ovum from systems along the North Atlantic Ocean. Shellfish collected from Northport Bay during the 2011 bloom had DSP toxin levels (1245 ng g−1 total OA congeners) far exceeding the USFDA action level (160 ng g−1 total OA of shellfish tissue) representing the first such occurrence on the East Coast of the U.S. D. acuminata blooms co-occurred with paralytic shellfish poisoning (PSP) causing blooms of Alexandrium fundyense during late spring each year of the study. D. acuminata cell abundances were significantly correlated with levels of total phytoplankton biomass and Mesodinium spp., suggesting food web interactions may influence the dynamics of these blooms. Given that little is known regarding the combined effects of DSP and PSP toxins on human health and the concurrent accumulation and depuration of these toxins in shellfish, these blooms represent a novel managerial challenge.  相似文献   

19.
    
Recent climate reconstructions are analyzed specifically for insights into those patterns of climate variability in past centuries with greatest impact on the North American region. Regional variability, largely associated with the El Nino/Southern Oscillation (ENSO) phenomenon, the North Atlantic Oscillation (NAO), and multidecadal patterns of natural variability, are found to mask the emergence of an anthropogenic temperature signal in North America. Substantial recent temperature anomalies may however indicate a possible recent emergence of this signal in the region. Multidecadal North Atlantic variability is likely to positively reinforce any anthropogenic warming over substantial parts of North America in coming decades. The recent magnitudes of El Nino events appear to be unprecedented over the past several centuries. These recent changes, if anthropogenic in nature, may outweigh the projection of larger-scale climate change patterns onto the region in a climate change scenario. The implications of such changes for North America, however, are not yet clear. These observations suggest caution in assessing regional climate change scenarios in North America without a detailed consideration of possible anthropogenic changes in climate patterns influencing the region.  相似文献   

20.
Carabelli’s trait is a morphological feature that frequently occurs on the mesiolingual aspect of Homo sapiens upper molars. Similar structures also referred to as Carabelli’s trait have been reported in apes and fossil hominins. However, the morphological development and homology of these mesiolingual structures among hominoids are poorly understood. In this study, we employ micro-computed tomography to image the enamel-dentine junction (EDJ) and outer enamel surface (OES) of Pan (n = 48) and H. sapiens (n = 52) upper molars. We investigate the developmental origin of mesiolingual features in these taxa and establish the relative contribution of the EDJ and enamel cap to feature expression. Results demonstrate that mesiolingual features of H. sapiens molars develop at the EDJ and are similarly expressed at the OES. Morphological variation at both surfaces in this taxon can satisfactorily be assessed using standards for Carabelli’s trait developed by the Arizona State University Dental Anthropology System (ASUDAS). Relative to H. sapiens, Pan has an even greater degree of correspondence in feature expression between the EDJ and OES. Morphological manifestations in Pan molars are not necessarily limited to the protocone and are best characterized by a lingual cingulum that cannot be captured by the ASUDAS. Cusp-like structures, similar to those seen in marked Carabelli’s trait expressions in H. sapiens, were not found in Pan. This study provides a foundation for further analyses on the evolutionary history of mesiolingual dental traits within the hominoid lineage. It also highlights the wealth of morphological data that can be obtained at the EDJ for understanding tooth development and for characterizing tooth crown variation in worn fossil teeth.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号