studia universitatis babeş-bolyai biologia 2

N. TOMESCU, L. OLARIU
The bibliographic sources that were used include synthetic papers on
Isopod fauna in Romania and Europe. [2 - 4, 6].
Description of species
Dimensions: The males that were collected were 8-11 mm long and 4-5.5 mm broad.
Colour: The tergites are dark brown. The base of the epimera displays yellow-orange
spots that form longitudinal bands. Some individuals also present spots on the
posterior extremity of the epimera.
Somatic characters: The cephalon has the lateral lobes very well developed, of
approximately triangular shape, inclined laterally, having the distal extremity
rounded and narrower than their basis. The median lobe is less developed, its sides
form an obtuse angle (Fig. 1 – A).
Tergites I – IV have the posterior margin slightly excavated. The glandular pore
fields have a circular shape, and are very close to the lateral margin of the epimera
(Fig. 1 – G), in some individuals being very close to the edge.
The pleotelson is short, the distal half has a large basis and an acute apex (Fig. 1 –
D).
Appendages: The antennae have the penultimate article shorter than the last one
(Fig. 1 – B), the length ratio between them being 0.8:1.
Pereiopods VII in males have the carpopodites provided with a narrow crest, like a
blade, which covers 80% of the length of the carpopodite (Fig. 1 – C).
Pleopods 1 exopodites in males have the distal half much narrower compared to
the proximal half (Fig. 1 – F). The extremity of endopodites 1 (gonopods) bears a
row of hairs that have their extremity shorter than the edges of the seminal duct.
The secondary sexual characters that distinguish the described species from the
species that are already known are pereiopods VII crest and the shape of pleopods
1 exopodites, characters that differentiate most of the species of genus Trachelipus.
Trachelipus radui n.sp. has the crest of the carpopodite similar to that of
Trachelipus pseudoratzeburgi, but other characters are different.
Ecology. The population from which the described individuals have been collected
lives in a very damp habitat, with rich herbaceous vegetation and also wooden
vegetation composed of alder trees. During daytime, the animals stay hidden
underneath the rocks.
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