Agriculture Reference
In-Depth Information
þ
FIGURE 7.2
The Carpathians in the Alpine mountain system. (After V.
Mihailescu 1963.)
V
C
ARIABILITY
OF
HARACTERS
The systematic status assigned to different
species populations depends on the range
permitted in variability of characters. Thus, if wide variability in clitellar organs is assumed, some
of the species described could be combined to form a single species, but by limiting the variability,
they could be regarded as distinct species or, in certain cases, as subspecies of polytypic species.
Because of a present lack of agreement on the taxonomic significance of some characters of
lumbricid species, and even of lumbricid genera, we have studied the variability in morphology
and anatomy in a range of material of
Octodrilus
(approximately 2000 specimens) from almost the
whole range of known species. In addition to the V.V. Pop collection kept with the Institute of
Biological Research in Cluj-Napoca, Romania, the collection of Prof. V. Pop (1903 to 1976) at the
University of Cluj-Napoca, Prof. A. ZicsiÔs collection at the Etvs Lorand University in Budapest,
Hungary, and MichaelsenÔs collection in Hamburg, Germany, were studied.
Statistical processing of data on the variability of characters in local populations of the
Octodrilus
Octo-
drilus
species from the Carpathians and the Alps, when correlated with available data on other
species of the genus, leads to the following ordination of their relative diagnostic value within the
genus
Octodrilus
(Pop 1991):
At (sub)genus level: Position of male pores
At species level: Number and position of spermathecae; position of tubercula pubertatis;
position of clitellum; presence or absence of dorsal pores; setal ratio; shape of calciferous
glands
At subspecies level: Extension or length of typhlosole; number of segments; body size and
mass
Other characters are sometimes also important but are seemingly of less-discriminatory value.
Two ecological groups of
Octodrilus
species were recorded in the Carpathians: (1) widely dis-
tributed species, like
, found in a range of different
habitats and displaying a wide variability in nonspecific characters (size, segment number, typhlosole
Octodrilus exacystis
and
Octodrilus compromissus
