Gastropoda, general view on the systematic:
Acroloxidae:
Taxonomic position of the Acroloxidae in the system of Gastropoda:
| Taxonomy of the Acroloxidae (Pulmonata) | |||||
|---|---|---|---|---|---|
| Lindholm 1909 | Kozhov 1936 | Zilch 1959-60 | Abbott & Boss 1989 | Bekman & Starob. 1975 | |
| Order | Inoperculata | Basom- matophora | Basom- matophora | Basom- matophora | - |
| Superfamily | - | - | Lymnaeacea | Planorbioidea | - |
| Family | Limnaeidae | Ancylidae | Acroloxidae | Ancylidae | Acroloxidae |
| Subfamily | Ancylinae | Acroloxinae | - | Ferrissiinae | - |
| Genus | Ancylus | Pseud- ancylastrum | Pseud- ancylastrum | Pseud- ancylastrum | Pseud- ancylastrum Baicalancylus Gerstfeldti- ancylus |
| Number of species | 5 | 3 | - | - | 24 |
The pulmonate limpet genus Pseudancylastrum Lindholm, 1909
was first regarded to belong to the Ancylinae (Planorbioidea), but later
anatomical investigations (Kozhov, 1936, Hubendick 1961) showed that the
limpets are orientated to the right and the genus Pseudancylastrum
was classified to the Acroloxinae.
The aperture has a round-oval shape. The apex of the shell
is bended backwards or distinctly tillt to the left. Only having at hand
conchiological characters the paleontologist may misinterpretate.
Acroloxidae of the genus Gerstfeldtiancylus
As in Choanomphalus the number of species
of Pseudancylastrum is under question. While in Lindholm´s work
(1909) 5 species were listed, later authors (Kozhov, 1936, Zhadin, 1952)
reduced the number to 3 regarding some of the morphes only as intraspecific
variations. Starobogatov (1989) regarded these species as genera and according
to conchiological differences in the correlation of shell parametres (hight,
length, width, position of the apex) he recently distiguished 24 species
(1998). Whether all these morphes represent biospecies or only ecomorphes
in the ranges of intraspecific variation is not clear yet.
On our expeditions 16 species according to Starobogatov and
Sitnikova (1998) were investigated.
© Röpstorf (Institute of Geological
Sciences - Palaeontology, Limnological Institute Irkutsk), DFG;
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