Beecheria bovidens (Morton, 1836)

brachial valve

pedicle valve

General abundance: Rare
This is the only specimen collected at this locality.

Discussion:

This rather small brachiopod has nearly parallel sides and an
elongate pedicle opening, and if examined with magnification you
can see many small pores in the shell.

Viewer Comments:

Beecheria bovidens is often listed as a species of the genus
Dielasma. However, brachiopods are homeomorphic and show convergent
evolution between major groups. Classification has to be based on
internal features in most cases. Probably the most distinct
difference between Beecheria and Dielasma is that in the former there
are two septa that support the cardinal plate on the interior of the
pedicle valve and the latter has but a single septum supporting the
cardinal plate. One needs to make serial sections or have
disarticulated valves to see this. For a complete discussion on
Dielasma and Beecheria, see Stehli (1956).

Composita is another example of homeomorphy with Beecheria and
Dielasma. Composita, however, is an atrypoid brachiopod with spiralia
to support the lophophore (food gathering mechanism) whereas
Beecheria and Dielasma are terebratuloid brachiopods that have a loop
that supports the lophophore. Composita is not closely related to the
other two.

Dr. Roger Pabian

References:

Dunbar, C.O. and Condra, G.E., 1932, Brachiopoda of the Pennsylvanian
System in Nebraska; Nebraska Geological Survey, Bulletin 5, p.304,
pl.37, figs.33-34

Hoare, R. D., 1961, Desmoinesian Brachiopoda and Mollusca from
Southwest Missouri; University of Missouri Press, p.33, pl.1,
figs.25-26

Hoare, R.D., 1968, Pennsylvanian brachiopods of Ohio; Ohio Geological
Survey Bulletin 63, p.68, pl.22, figs.15-19

Stehli, F.G., 1956, Dielasma and its external homeomorph Beecheria;
Journal of Paleontology, v.30, p. 299-302

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