Sie können Bookmarks mittels Listen verwalten, loggen Sie sich dafür bitte in Ihr SLUB Benutzerkonto ein.
Medientyp:
E-Artikel
Titel:
Epizoans of the Middle Devonian Brachiopod Paraspirifer bownockeri: Their Relationships to One Another and to Their Host
Beteiligte:
Kesling, Robert V.;
Hoare, Richard D.;
Sparks, Diane K.
Erschienen:
Society of Economic Paleontologists and Mineralogists and the Paleontological Society, 1980
Erschienen in:Journal of Paleontology
Sprache:
Englisch
ISSN:
0022-3360;
1937-2337
Entstehung:
Anmerkungen:
Beschreibung:
<p>During a brief interval of Middle Devonian time, the soft clay mud flats near the southeastern edge of the Michigan Basin supported a community dominated by Paraspirifer bownockeri (Stewart). This large brachiopod served as host for numerous kinds of epizoans, most using the shell as available hard surface on which to settle. Our study is based on epifauna attached to 582 excellently preserved specimens of this Paraspirifer collected from the Silica Formation in a small area in northwestern Ohio. Each brachiopod was studied for distribution of each kind of epizoan in 41 grid locations on each valve. Epizoans are more numerous on brachial than on pedicle valves, reflecting the position we suppose for adult Paraspirifer after atrophy of the pedicle--resting stably on the pedicle valve. Distribution of epizoans is also asymmetric on each valve, being concentrated with more on one side of the brachial valve and on the diametrically opposite side of the pedicle valve; this we interpret as an indication that the currents bearing epizoan larvae and spat approached the majority of hosts at an angle, with differential success in settling controlled by eddies in the slipstream. Patterns of occupancy appear to have changed when the host attained 50-60 mm in width, probably coinciding with pedicle deterioration. Coverage of colonial organisms contrasts with noncolonial organisms, showing an astogenetic extension of the former into areas of the host less favorable for larval settlement. Certain common epizoan species occur together on the same host with much greater or much less frequency than expected by chance. Several explanations are suggested for these associations, including place of emigration, breeding seasons, mutualism, competition, larval vulnerability, and antagonism.</p>