ISSN:
1573-5117
Keywords:
Anostraca
;
Onchostraca
;
Cladocera
;
Copepoda
;
North-Africa
;
Biogeography
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Description / Table of Contents:
Sommaire Nous avons trouvé 56 espéces de Crustacés dans 126 échantillons collectionnés dans 62 localités différentes en Tunisie et dans la région de La Calla, Algérie. Aucune espéce n'est nouvelle pour la science, mais le matériel a permis de redéfinir l'espéce Alona elegans et d'indiquer par quels caractéres elle différe d' Alona rectangula. Un cas d'hybridisation possible entre ces deux espéces est cité de l'oasis de Tamerza. Si la plupart des espéces rencontrées en Tunisie ont une répartition géographique assez vaste, quelques-unes sont endémiques du Maghreb, tandis que d'autres sont des reliques pluviales venus soit du Nord, soit d'Afrique, soit encore de l'Orient, Les reliques Nordiques ont une age estimé á 5–6000 ans. En principe, les reliques Ethiopiens devraient dater d'une époque antérieure aux autres, mais il est possible qu'ils aient atteint le Maghreb venant de l'Est et aprés avoir descendu le Nil. Dans la collection, un seul élément Asiatique est représenté. D'autres doivent certainment exister dans la faune Tunisienne.
Notes:
Abstract In samples from 62 localities in Tunisia and La Calla area in N.E. Algeria, 56 species of Entomostraca were found. More than half of these are widespread and give little insight into the origin of the regional fauna. A few are endemic to the area and three groups are of relictual nature. The first one consists of northern species, some of which are known to have reached the central Sahara. It is argued that their populations have an estimated age of about 5–6000 yrs. At first sight, the second and more numerous group of species, the Ethiopian relicts, should be older. However, until historical times pathways ‘around’ the Sahara may have functioned. One was along the Atlantic coast; a second and older one was via the Nile. The second possibility is almost a certainty, since a third group of relicts, the Oriental one, has migrated into the central Sahara as far as (and therefore probably together with) the northern relicts. This group must have come via the Nile Delta and the Libyan desert. If that pathway has also been used by Ethiopian species, all three groups of relicts are of the same age. In our Tunisian collection, only one Oriental element is represented. From a taxonomical point of view, morphological differences between the Chydorids Alona rectangula Sars and Alona elegans Kurz are sorted out and illustrated. Alona rectangula is best regarded as a superspecies. Hybridisation with A. elegans appears possible.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00020908
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