Turbellarian taxonomic database

Convolutidae Oligochoerus Notes

Beklemischev VN 1963 (citation)-

Ax P, Doerjes J 1966 (citation)- describes a new species from fresh water belonging to this genus.
	Oligochoerus limnophilus- note other species are all from Caspian Sea. this is first
	fresh water Acoel known.  Gives definition of genus p 39- and key to species.   Discussion
	of geographic distribution and significance of new species.  p 39-41.
Dorjes J 1968 (citation)- p 66 notes problems here in systematics.  p 89- defines and list species 
	Oligochoerus erythrophthalmus Beklemischev 1963	
		O. bakuensis Beklemischev, 1963
		O. chlorella Beklemischev, 1963
		O. conops Beklemischev, 1963
		O. melanops Beklemischev, 1963
		O. limnophilus Ax & Doerjes 1966

Beklemischev VN 1969 (citation)- Volume II, p 39- notes 2 or 3 pairs of pyriform organs.		 
Henley C 1974 (citation)- p 294 notes Ax P, Doerjes J 1966 (citation) report of granules in sperm.
Kolasa J, Faubel A 1974 (citation)- Oligochoerus described in comparison to new fresh water 
	genus Limnoposthia [Bush note: Limnoposthia place in or close to Mecynostomidae].
Faubel A, Kolasa J 1978 (citation)- Oligochoerus described in comparison to new fresh water 
	genus Limnoposthia.

Vitellaria in acoels

According to the keys of Doerjes (1968) (citation) and Bush (1984) (citation), Oligochoerus and Polychoerus differ
from other acoels in having separate yolk-producing and germ regions in the ovary, something like the
vitellaria of other turbellarians. However, this idea comes from mistaken interpretations of histological
sections through ovaries in which larger oocytes are highly lobulated; the oocytes are really entolecithal
is true of all acoels and other archoophoran turbellarians.

Beklemischev (1963) (citation) points out this error (as it appeared in Lohner (1910) (citation), as well as in other
papers on these genera, including Costello & Costello (1938a,b) (citation) (citation)). On p. 63, he writes
[translated from the Russian by Anatoly Petrov]:

'In mature specimens both ovaries converge toward their posterior ends, forming a ring as in Avagina
incola (Lieper, 1904). In the last phases of the period of growth, the oocytes form numerous processes
like lobopodia of amoebae. The mature egg is round. Immediately behind the pharynx, the oogonia become
covered by the envelope of the flat parenchymal sells, and further posteriorly they are submerged in the
common stroma of the same kind of cells. The ovaries of P. caudatus have an evidently similar structure;
Lohner (1910, table XVI, fig. 9) mistook the whole set of lobated processes of the mature oocyte for the
special vitellarium.'

In the caption to Figure 3 showing part of the ovary in O. conops (see image under that species name in this
database), Bekelmischev writes 'G [4th part]. Oocyte at end of period of growth with long processes. The
cytoplasm is overfilled with inclusions. The nucleus has a large nucleolus. Around it are nuclei of young
oocytes, the cell bodies of which are not depicted.'

Return to Convolutidae Oligochoerus