Biometry and taxonomy of Adriatic <i>Ammonia</i> species from Bellaria–Igea Marina (Italy)
<p>Living <i>Ammonia</i> species and an inventory of dead assemblages from Adriatic subtidal, nearshore environments were investigated at four stations off Bellaria, Italy. <i>Ammonia falsobeccarii, Ammonia parkinsoniana, Ammonia tepida</i>, and <i>Ammonia veneta&...
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| Autores principales: | , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/d1b044a53efd4b7ca1a022a461a31486 |
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| Sumario: | <p>Living <i>Ammonia</i> species and an inventory of dead assemblages from Adriatic
subtidal, nearshore environments were investigated at four stations off
Bellaria, Italy. <i>Ammonia falsobeccarii, Ammonia parkinsoniana, Ammonia tepida</i>, and <i>Ammonia veneta</i> were recognized in the living (rose-bengal-stained)
fauna, and <i>Ammonia</i> <i>bellaria</i> n. sp. is described herein for the first time. <i>Ammonia beccarii</i> was only found
in the dead assemblage. The biometry of 368 living individuals was analysed
by using light microscopic and scanning electron microscopic images of three
aspects. A total of 15 numerical and 8 qualitative parameters were measured and
assessed, 5 of which were recognized to be prone to a certain
subjectivity of the observer. The accuracy of numerical data as revealed by
the mean residuals of parallel measurements by different observers ranged
from 0.5 % to 5.5 %. The results indicated a high degree of intraspecific
variability. The test sizes of the individual species were log-normally
distributed and varied among the stations. Parameters not related to the
growth of the individuals, i.e. flatness of the tests, dimensions of the
second-youngest chamber, proloculus, umbilical and pore diameter,
sinistral–dextral coiling, and umbilical boss size, were recognized as being
species-distinctive in combination. They may well supplement qualitative
criteria that were commonly used for species discrimination such as a lobate
outline, a subacute or rounded peripheral margin, or the degree of
ornamentation on the spiral and umbilical sides. The averages of the
measured parameters were often lower than the range of previously published
values, mainly because the latter were retrieved from a few adult specimens
and not from the whole assemblage as in the present approach. We conclude
that the unprecedented high proportions of <i>Ammonia beccarii</i> in the northern Adriatic may
well be artificial. A robust species identification without genetic analyses
is possible by considering designated biometric parameters. This approach is
also applicable to earlier literature data, and their re-assessment is
critical for a correct denomination of recent genotypes.</p> |
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