Les Nàiades (Mollusca: Bivalvia: Unionoida) dels Països Catalans Authors Cristian R. Altaba Abstract The unionoids of the Catalan Countries have been revised considering characters from the shell, the glochidium larvae, and the topographical anatomy. Four species are recognized. Margaritifera auricularia is known from the rivers Ter and Ebre; the latter harbors the last known living population of the species. Anodonta cygnea is widely distributed in the lowlands. Psilunio littoralis is subdivided into five subspecies:P. I. Littoralis from the River Ter northwards, P. I. Subreniformis in Lake Banyoles, P. I. Catalonicus in the small rivers of the Catalan Central Depression, P. I. Umbonatus from the Ebro southwards, and P. I. Gandiensis in the northern slope of the Dianic Ranges. Four subspecies are also recognized of Unio elongatulus: U. e. Aleroni from the Rosselld Plain to the Tordera River, U. e. Penchinatianus in Lake Banyoles, U. e. ssp. in the River Ebro, and U. e. Valentinus along the Gulf of Valencia. No unionoid lives in the Balearic Islands. The intense differentiation of Catalan naiades appears to be caused by the scarcity of freshwater environments in a Mediterranean climate, and by the patterns of dispersal of the fishes that are hosts for the unionoid larvae. All the naiades in the Catalan Countries are at present in regression due to human activities. M. auricularia and the endemisms of Banyoles are endangered. Downloads Download data is not yet available. Downloads Text complet (Català) Published 2005-05-31 Issue Vol. 60 : 1992 (Secció de Zoologia, 9) Section Articles License The intellectual property of articles belongs to the respective authors.On submitting articles for publication to the journal Butlletí de la Institució Catalana d'Història Natural authors accept the following terms:Authors assign to Institució de la Societat Catalana d’Història Natural (a subsidiary of Institut d’Estudis Catalans) the rights of reproduction, communication to the public and distribution of the articles submitted for publication to Butlletí de la Institució Catalana d'Història Natural.Authors answer to Institució de la Societat Catalana d’Història Natural for the authorship and originality of submitted articles.Authors are responsible for obtaining permission for the reproduction of all graphic material included in articles.Institució de la Societat Catalana d’Història Natural declines all liability for the possible infringement of intellectual property rights by authors.The contents published in the journal, unless otherwise stated in the text or in the graphic material, are subject to a Creative Commons Attribution-NonCommercial-NoDerivs (by-nc-nd) 3.0 Spain licence, the complete text of which may be found at https://creativecommons.org/licenses/by-nc-nd/3.0/es/deed.en. Consequently, the general public is authorised to reproduce, distribute and communicate the work, provided that its authorship and the body publishing it are acknowledged, and that no commercial use and no derivative works are made of it.The journal Butlletí de la Institució Catalana d'Història Natural is not responsible for the ideas and opinions expressed by the authors of the published articles.