Intraspecific geographic-morphological variation patterns in Fucus distichus and F. evanescens

1985 ◽  
Vol 88 (2) ◽  
pp. 207-215 ◽  
Author(s):  
E. L. Rice ◽  
T. J. Kenchington ◽  
A. R. O. Chapman
Zootaxa ◽  
2007 ◽  
Vol 1434 (1) ◽  
pp. 1 ◽  
Author(s):  
MARIA EDUARDA CASTRO LEAL ◽  
PAULO M. BRITO

The caudal fin skeleton has been regarded as a major source of characters used in the evaluation of teleostean interrelationships. Despite the increasing number of papers drawing attention to the variability observed within species when large samples are considered, intraspecific variation of this complex remains poorly known for many teleostean groups, and comparative anatomical studies still often rely on a small number of specimens. Within the Osteoglossomorpha, there are few studies concerning instraspecific variation patterns, and many aspects of both the anatomy and homology of the caudal fin skeleton elements are controversial (e.g. epurals versus uroneurals; number of hypurals compounding the “hypural fan”). Given this perspective, we examined the caudal skeleton of 84 specimens of the neotropical osteoglossid fish Osteoglossum bicirrhosum, and described and quantified its morphological variation. We determined that the number of neural spines on the preural centra and hypural fusion patterns showed the greatest variation. Despite the widespread distribution of this taxon, the observed variation appears to be geographically independent, and occurs randomly within populations. 


1988 ◽  
Vol 66 (8) ◽  
pp. 1583-1609 ◽  
Author(s):  
J. G. Chmielewski ◽  
C. C. Chinnappa

Patterns of morphological variation were examined among pistillate and staminate plants of Antennaria rosea Greene s.l. and northwestern microspecies in section Dioicae which are often placed in synonomy with A. rosea. The variation observed among pistillate plants was not correlated with geography, but in certain regions such as southern Yukon, Banff and Jasper national parks, the Cypress Hills of southeastern Alberta, and in the southern range limits the likelihood of finding atypical specimens increases. The northwestern taxa A. breitungii, A. elegans, A. incarnata, A. laingii, A. leuchippi, A. oxyphylla, and atypical forms of A. subviscosa, although similar in many characteristics to A. rosea, do represent distinct morphological entities. The fact that these taxa maintain their distinctive morphologies under controlled transplant studies suggests that their species rank may be maintained. Staminate plants in the northeastern portion of their distribution were consistently larger than those found elsewhere. The importance of vegetative and vegetative–reproductive characters in the discriminant function suggests that the morphological differences are in response to environmental factors.


1971 ◽  
Vol 49 (8) ◽  
pp. 1463-1469 ◽  
Author(s):  
J. McLachlan ◽  
L. C.-M. Chen ◽  
T. Edelstein

Mature thalli of Fucus distichus, F. edentatus, F. serratus, and F. vesiculosus were obtained in unialgal culture from zygotes and were grown in an enriched seawater medium. The two former species were maintained in culture for more than 2 years, in which time the length of thalli of F. edentatus never exceeded 4 cm. The other species grew reasonably well with a maximum rate of elongation of about 1 cm per month for F. serratus. In all species the rates of growth were less than that observed in nature. Fertile receptacles with viable gametes were formed in F. distichus, but the other species never attained reproductive maturity. All specimens retained their characteristic morphology under identical conditions of culture, and it is suggested that morphological variation amongst Fucus spp. is due mainly to hybridization rather than to environmental conditions. There was no indication that any of these species required intertidal conditions, and no unique nutritional requirements were identified.


1983 ◽  
Vol 61 (6) ◽  
pp. 1692-1717 ◽  
Author(s):  
William J. Crins ◽  
Peter W. Ball

The Carex pensylvanica complex consists of four North American taxa. Morphological variation patterns within the complex were examined using principal-components analysis and discriminant-functions analysis. These results indicate that two eastern species, C. lucorum Willdenow ex Link, and C. pensylvanica Lamarck, and one western species, C. inops Bailey, should be recognized. The latter species comprises two subspecies, C. inops subsp. inops and C. inops subsp. heliophila (Mackenzie) Crins, comb. nov. Cytological and geographical evidence lend support to this classification. A key and distribution maps for the taxa are provided.


1982 ◽  
Vol 93 (1-2) ◽  
pp. 71-76
Author(s):  
S. Kokkini ◽  
D. Babalonas

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