ISSN:
1573-5117
Schlagwort(e):
Cladocera
;
Daphniidae
;
taxonomy
;
biogeography
;
hyponeuston
;
Megafenestra
;
Scapholeberis
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract The group of hyponeustonic daphniid cladocera previously known under the generic name Scapholeberis is raised to the rank of a subfamily (Scapholeberinae) and contains two genera, Megafenestra n.gen. (2 species), and Scapholeberis s.s. (7 species and one subspecies). The characters upon which this revision is based are: structure of the rostrum, structure of the first antennae, structure of trunk limbs 1, 2, and 5, presence and nature of headpore(s), structure of the ventral rim of the valves, armature of the distal rim of the valves, structure of the postabdomen and its end-claws. Males were examined in all but two species, and proved to be more primitive than females and much less diagnostic than in the Chydoridae. It also appeared that the shape and armature of the postabdomen are less important taxonomical tools than heretofore supposed. In more than half of the species, it is of generalised shape and hardly usable beyond the species-group level. The same, although less drastically, holds true for the P1 of males. Of greatest diagnostic value at the species level are the shape of the rostrum and the armature of the valve margins. A phylogeny of the subfamily is proposed, with Megafenestra as the more primitive genus, closely allied to Ceriodaphnia, and within Scapholeberis, S. mucronata as the most apomorphic species. In biogeographical respect, no species is cosmopolitan, although their ranges may be of continental dimensions. Species and populations appear to concentrate in the temperate and continental climate belts of the northern hemisphere, but more research in the southern hemisphere is needed. A key for the identification of all species is given.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00027420
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