Distribution and Geographic Variation in Three South American Grassquits (Emberizinae, Tiaris)

1997 ◽  
pp. 91-110 ◽  
Author(s):  
John M. Bates
Keyword(s):  
Geographic Variation ◽  
South American

Geographic variation in the laryngeal morphology of a widely distributed South-American anuran: behavioural and evolutionary implications

2020 ◽  
Vol 190 (1) ◽  
pp. 140-148 ◽  
Author(s):  
Carlos López ◽  
Maricel Quispe ◽  
Aldo Villalón ◽  
Miguel L Concha ◽  
Mario Penna ◽  
...  
Keyword(s):  
Geographic Variation ◽  
Communication Systems ◽  
Acoustic Signals ◽  
Dominant Frequency ◽  
South American ◽  
Arytenoid Cartilage ◽  
Acoustic Characteristics ◽  
Advertisement Calls ◽  
Biogeographic Patterns ◽  
Dilator Muscle

Abstract Sound-producing organs generate acoustic signals that have a fundamental role in communication systems. In species exhibiting different biogeographic patterns, variations of these structures can explain a large part of interpopulation differences of their signals. Pleurodema thaul is an anuran with an extensive geographic distribution in Chile and presents an evident divergence in its acoustic signals among three genetic/bioacoustic groups (i.e. northern, central and southern). By means of classic histology and 3D-reconstructions, we study the geographic variation in the larynx of P. thaul males from these three groups. In addition, volumes of six laryngeal structures are used as predictors of acoustic characteristics of advertisement calls recorded in previous studies for the same subjects used in the current study. After removing the effect of body size, the arytenoid cartilage, dilator muscle and vocal cords show significant differences between the three bioacoustic groups. Furthermore, arytenoid cartilage and dilator muscle volumes predict some temporal parameters and also the dominant frequency of advertisement calls. Our results show important geographic variation in laryngeal morphology, which is in correspondence with acoustic, behavioural and genetic variation in this species.

scholarly journals Virulence diversity of Phakopsora pachyrhizi in Mexico

2021 ◽  
Author(s):  
Julio César García-Rodríguez ◽  
Zeferino Vicente-Hernández ◽  
Manuel Grajales-Solís ◽  
Naoki Yamanaka
Keyword(s):  
Comparative Analysis ◽  
South America ◽  
Geographic Variation ◽  
Soybean Rust ◽  
South American ◽  
Phakopsora Pachyrhizi ◽  
Common Trend ◽  
Asian Soybean Rust ◽  
Production Knowledge ◽  
Virulence Diversity

Asian soybean rust (ASR), caused by the pathogen Phakopsora pachyrhizi, is the main disease of soybean in Mexico and worldwide, threatening its production. Knowledge about the virulence of Mexican rust populations (MRPs) is crucial in order to develop or introduce soybean cultivars with resistance to this disease. This study investigated the geographic variation on the virulence of 19 MRPs collected in two states of Mexico: Tamaulipas and Chiapas, using a set of 12 differential soybean varieties. The inoculation of MRPs showed that there was no large difference in virulence to differentials carrying Rpp4 or Rpp5 between MRPs from the two states. However, a contrasting phenotype was observed on Rpp1, Rpp1-b, Rpp2, and Rpp3. In the comparative analysis of virulence profiles with 157 and 20 P. pachyrhizi samples from South America and Asia, respectively, the MRPs from Chiapas form an isolated cluster, including the Tamaulipas state. The MRPs from Tamaulipas clustered with South American samples because of common characteristics, such as virulence to Rpp1 and avirulence to Rpp1-b. However, opposite reactions on Rpp1 and Rpp1-b that have been reported in major USA pathogen were also observed in Chiapas samples. A common trend between Chiapas and major USA pathogen was also observed in Rpp3. As the main conclusion of the present study, the 1,000 km distance between these two states in Mexico makes a big difference in the virulence of ASR.

Geographic Variation in Fluted Projectile Points: A Hemispheric Perspective

1999 ◽  
Vol 64 (2) ◽  
pp. 215-230 ◽  
Author(s):  
Juliet E. Morrow ◽  
Toby A. Morrow
Keyword(s):  
North America ◽  
South America ◽  
Geographic Variation ◽  
Great Plains ◽  
North American ◽  
South American ◽  
Western North America ◽  
Radiocarbon Dates ◽  
Projectile Points ◽  
Fluted Points

This paper examines geographic variation in fluted point morphology across North and South America. Metric data on 449 North American points, 31 Central American points, and 61 South American points were entered into a database. Ratios calculated from these metric attributes are used to quantify aspects of point shape across the two continents. The results of this analysis indicate gradual, progressive changes in fluted point outline shape from the Great Plains of western North America into adjacent parts of North America as well as into Central and South America. The South American “Fishtail” form of fluted point is seen as the culmination of incremental changes in point shape that began well into North America. A geographically gradual decline in fluting frequency also is consistent with the stylistic evolution of the stemmed “Fishtail” points. Although few in number, the available radiocarbon dates do suggest that “Fishtail” fluted points in southern South America are younger than the earliest dates associated with Clovis points in western North America. All of these data converge on the conclusion that South American “Fishtail” points evolved from North American fluted points.

Geographic Variation in the South American Cricetine Rodent Bolomys lasiurus

1987 ◽  
Vol 68 (3) ◽  
pp. 578-594 ◽  
Author(s):  
R. H. Macedo ◽  
M. A. Mares
Keyword(s):  
Geographic Variation ◽  
South American ◽  
The South

scholarly journals On clutch size and hatching success of the South American turtles Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae)

2003 ◽  
Vol 75 (4) ◽  
pp. 415-430 ◽  
Author(s):  
Paulo Emilio Vanzolini
Keyword(s):  
Regression Analysis ◽  
Geographic Variation ◽  
Clutch Size ◽  
Egg Size ◽  
Hatching Success ◽  
South American ◽  
Geographic Differentiation ◽  
Egg Volume ◽  
The South ◽  
Podocnemis Expansa

Data on clutch size and hatching success of P. expansa were gathered for seven beaches traditionally used by the species and re-analyzed statistically by means of regression analysis, of the number of eggs on the number of females (or nests) and of the number of young on the number of eggs. All regressions were linear, passed through the origin and had excellent fits. Average clutch size varied from 75 to 123, and presented geographic differentiation: (i) Rio Orinoco, (ii) Rio Trombetas + Rio Branco and (iii) Rio Juruá + Rio Purus. Average hatching success was ca. 83%. In P. unifilis there was also geographic variation in clutch size, the Iquitos area showing the highest values. Hatching success of P. unifilis was uniformly high: only one sample, from Iquitos, had less than 90% success. The outstanding fit of the clutch size regressions leads one to consider egg volume variability, which was found to be high in both species, in contradiction with current optimal egg size theory.

Geographic variation in the foraging behaviour of South American fur seals

2018 ◽  
Vol 596 ◽  
pp. 233-245 ◽  
Author(s):  
AMM Baylis ◽  
M Tierney ◽  
RA Orben ◽  
IJ Staniland ◽  
P Brickle
Keyword(s):  
Geographic Variation ◽  
Foraging Behaviour ◽  
South American ◽  
Fur Seals
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