Geometrías delicadas: Dise？os grabados en cáscaras de huevo de Rheidae recuperados en la costa norte del Golfo San Matías, Río Negro

this paper presents the results of the analysis of 170 decorated eggshell fragments of rheidae, surface finds recorded at several archaeological localities on the northern shore of san matías gulf, río negro. a description and analysis of the designs and engraving techniques used in their creation is presented. in order to infer the decorative techniques, all the materials were subject to microscopic observations, complemented with a brief series of systematic experiments carried out on fresh american ostrich eggshell to obtain independent comparative criteria. it is concluded that there is a trend that links the high/intermediate production quality with a) a greater variety of motif classes and b) several of the most complex motifs. finally, the motif repertoire observed on the engraved eggshell fragments is compared to that of other decorated materials from patagonia. there are clear similarities with the designs of lithic plaques, ceramic vessels and rock art. in spite of the fact that none of these materials were necessarily contemporary, this leads to the suggestion that such designs may have formed part of a broader supraregional system of visual communication, which exceeded the limits of the northern patagonian coast.