Multivariate morphometric analysis of two varieties of Littorina saxatilis from the Swedish west coast

Janson, Kerstin; Sundberg, Per

doi:10.1007/bf00394274

Cited by 86 publications

(66 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…With the evidence for gene flow between the ecotypes in each system they were all considered to belong to one species, namely, L. saxatilis. Given the high fitness of hybrids (in their habitat) and the smooth transition between the extreme ecotypes in the Swedish system it was considered unlikely that this represented a situation in which reproductive isolation might arise [33,34], and see Sadedin et al [35]. A more likely candidate system for the evolution of isolation might be the Galician ecotypes, which show greater genetic differentiation on average [7].…”

Section: Do the Ecotypes Represent A Stage In Speciation?mentioning

confidence: 99%

Ecological Speciation and the Intertidal Snail Littorina saxatilis

Galindo

Grahame

2014

Advances in Ecology

View full text Add to dashboard Cite

In recent decades biologists studying speciation have come to consider that the process does not necessarily require the presence of a geographical barrier. Rather, it now seems to be possible for reproductive barriers to evolve within what was hitherto a single "species. " The intertidal snail Littorina saxatilis has been the focus of a considerable amount of work in this context, and it is now thought of as a good case study of "ecological speciation. " We review some of this work and briefly consider prospects for future developments.

show abstract

Section: Do the Ecotypes Represent A Stage In Speciation?mentioning

confidence: 99%

Ecological Speciation and the Intertidal Snail Littorina saxatilis

Galindo

Grahame

2014

Advances in Ecology

View full text Add to dashboard Cite

show abstract

“…Raffaelli, 1979;Reimchen, 1981;Naylor & Begon, 1982;Janson & Sundberg, 1983). Our investigation illustrates that morphological variation may be found among units of populations that are smaller than previously assumed, and may be found not only between different shore types (e.g.…”

Section: Within-site Variation At Herdlamentioning

confidence: 65%

“…In L. saxatilis, migration rates (Janson, 1983), and gene flow (Janson & Ward, 1984, K. Johannesson & B. Johannesson, this volume) are small over distances of a few metres or less, and this may result in both phenotypic and genotypic variation at a scale of only a few metres. Dramatic shifts from one phenotype to another have also been shown to take place over distances of 5 to 50 m where a brackish water seagrass bed borders a boulder shore (Janson & Ward, 1985), or where a boulder shore borders a rocky cliff face (Janson & Sundberg, 1983;Janson & Ward, 1984).…”

Section: Within-site Variation At Herdlamentioning

confidence: 99%

Littorina neglecta Bean, a morphological form within the variable species Littorina saxatilis (Olivi)?

Johannesson¹,

Johannesson²

1990

Hydrobiologia

View full text Add to dashboard Cite

The morphological variation of Littorina saxatilis and L. neglecta on a microscale (vertical transects down a shore) and on a geographical scale (Northeastern Atlantic) was examined to see if the sampled snails could be consistently separated into two groups on morphological criteria. Size, shell form and shell banding pattern, subopercular pattern and size at maturity were recorded for 21 samples from different shore levels (barnacle zone -usual habitat of L. neglecta, low littoral fringe and high littoral fringe -usual habitat of L. saxatilis) in Iceland, Norway, Sweden, Isle of Man and Wales. A multivariate approach (principal component analysis) was applied to analyse 14 quantitative shell characters. Between-shore variation in shell shape of samples from similar levels was generally larger than within-shore variation of samples from different levels, while size of snails was consistently smaller in barnacle zone compared to littoral fringe samples. The frequency of snails with qualitative characters, used in earlier studies to define L. neglecta, differed between samples from the littoral fringe and the barnacle zone at each site (except at the Swedish site), but the differences between geographical areas were generally larger. The results indicate that snails fitting earlier descriptions of L. neglecta are present in the barnacle zone in Iceland, Norway, Isle of Man and Wales, but that this form is not clearly distinguishable from L. saxatilis. Snails with intermediate shapes were common and, furthermore, the qualitative and the quantitative characters used to define L. neglecta were not closely coupled. No snails of L. neglecta form were found at the Swedish site, yet shape differences over the intertidal gradient were greatest at this site.The extensive morphological variation found in L. saxatilis, between shores and between microhabitats on the same shore, is likely to be due to low gene-flow within the species and a heterogeneous environment. The area over which mating can be random is probably small, thus a subpopulation will behave as a semi-isolate with more or less unique ecological and evolutionary factors influencing its detailed morphology.

show abstract

“…To select characters for use in morphometric analyses, we reviewed the available morphometric studies of marine and freshwater gastropods from the literature (Janson 1982;Janson and Sundberg 1983;Armbruster 1995;Chiu et al, 2002) and adopted shell characters that appeared practical in identification. The results of morphometric analyses might directly reflect the importance and effect of each character.…”

Section: Morphometricsmentioning

confidence: 99%

Untitled

Marzouk¹,

Chenuil²,

Blel³

et al. 2016

Turk. J. Fish. Aquat. Sci.

View full text Add to dashboard Cite

Morphological studies of species with wide distribution range and high commercial value, such as the banded murex Hexaplex trunculus (Linnaeus, 1758), provide information on stock structure, which is the basis for understanding fish population dynamics and enable resource assessment for fisheries management. In the present study, we examined morphological variation among Atlantic and Mediterranean populations of H. trunculus using multivariate analysis. Our results supported the existence of four distinguishable stocks (Atlantic, Alboran, Western Mediterranean and Eastern Mediterranean), correctly classified 71.7% of specimens, and indicated significant degrees of variation in morphometric characteristics between regions. Examination of the contribution of each morphometric variable to the principal components and canonical functions indicated that differences among samples seemed to be associated with the shell and aperture length and width. Samples from the Atlantic Ocean and the Alboran Sea had the largest shell size and the greatest morphometric divergence. This strong morphometric differentiation appears to be associated with local environmental factors (exposure on the rocky shores, food availability and predation) and oceanographic current barriers.

show abstract

Multivariate morphometric analysis of two varieties of Littorina saxatilis from the Swedish west coast

Cited by 86 publications

References 7 publications

Ecological Speciation and the Intertidal Snail Littorina saxatilis

Ecological Speciation and the Intertidal Snail Littorina saxatilis

Littorina neglecta Bean, a morphological form within the variable species Littorina saxatilis (Olivi)?

Untitled

Contact Info

Product

Resources

About