Macedonethes stankoi n. sp., a rhithral oniscidean isopod (Isopoda: Oniscidea: Trichoniscidae) from Macedonia

Abstract

Macedonethes stankoi n. sp. is described, a truly aquatic species with special morphological adaptations to life in running water. Diagnosis of Macedonethes stankoi n. sp. (Fig. 1): Species with the characters diagnostic for Macedonethes Buturović, 1955 (see alsoTabacaru 1993). Blind. Body large (up to 15.7 mm long), rather convex. Defined mostly by characters interpreted as adaptations to life in rhithral habitats: cephalon hypognathous, antennular article 3 and aesthetascs reduced to varying degree (from slightly developed with two aesthetascs to almost totally reduced); pereopods 1-4 subchelate, i.e. with elongate carpus opposed to propodus and dactylus (enabling the animal to attach tightly to the substrate); sternum of pereonite 5 with unique clasping structures (presumably facilitating copulation); exopod of male pleopod 1 remarkably dilated mediodistally; endopod of male pleopod 2 with arched apical article; exopods of pleopods 2-5 with long plumose setae on posterior margins; epimera of pleonites 3-5 well developed. Types and locality: Holotype male (Macedonian Museum of Natural History, Skopje; Inv. No. 2783); Macedonia, Jakupica Mt., slopes of Solunska glava peak, from a spring in the cave at the source of the Babuna River, 1500 m asl (UTM-EM31), 18.08.2000, leg. G. Poliić. Paratypes: 4 males and 2 females as holotype (Inv. No. 2784); 2 males and 1 female as holotype, except in author's collection; 1 male and 1 female as holotype, except in Museo Zoologico "La Specola", University of Florence, Italy. Spelaeonethes castellonensis Cruz & Dalens, 1989 clearly differs from the characteristics of Spelaeonethes species, particularly in structures of the male merus 7 and the endopods of male pleopods 2. Published descriptions and illustrations demonstrate obvious close relations with the type species of Macedonethes, M. skopjensis Buturović, 1955, especially regarding all characters considered diagnostic for that genus. Therefore, the new combination Macedonethes castellonensis (Cruz & Dalens) is proposed. A detailed description (including color plates), further discussion of adaptations, and data on other aquatic oniscids are presented in an Electronic Supplement.