The idea of an area of endemism implies that different groups of plants and animals should have largely coincident distributions. This paper analyses an area of 1152 000 km2, between parallels 21 and 32°S and meridians 70 and 53°W to examine whether a large and taxonomically diverse data set actually displays areas supported by different groups. The data set includes the distribution of 805 species of plants (45 families), mammals (25 families), reptiles (six families), amphibians (five families), birds (18 families), and insects (30 families), and is analysed with the optimality criterion (based on the notion of endemism) implemented in the program NDM/VNDM. Almost 50% of the areas obtained are supported by three or more major groups; areas supported by fewer major groups generally contain species from different genera, families, or orders. © The Willi Hennig Society 2011.

We describe a new species of capuchino of the genus Sporophila 1 (Emberizidae) of the Esteros del Iberá, province of Corrientes, in northeastern Argentina. 2 This species would have remained unidentified due to lack of ornithological explorations in 3 the central area of the Esteros del Iberá. It has been confused with immature individuals of 4 other Sporophila species. We made observations of behavior and habitat, playback 5 experiments, comparative analyzes of the vocalizations and plumage with other sympatric 6 species of the same genus, and we found this species, which we have named Sporophila 7 iberaensis, inhabiting wet grasslands from the edges of the marshes, having a unique vocal 8 repertoire and a unique plumage. Because of its restricted geographical distribution and the 9 threats that have their habitat, this new species should be categorized as Vulnerable on the 10 IUCN Red List. 11 Sporophila, vocalizations 13 14 RESUMEN.-Describimos una nueva especie de capuchino del género Sporophila 15 (Emberizidae) de los Esteros del Iberá, provincia de Corrientes, en el noreste de Argentina. 16 Esta especie habría permanecido sin identificar debido a la falta de exploraciones 17 ornitológicas en la región central de los Esteros del Iberá y además habría sido confundida 18 con individuos inmaduros de otras especies de Sporophila. Realizamos observaciones de 19 comportamiento y hábitat, experimentos de playback, análisis comparativos de las 20 vocalizaciones y comparaciones del plumaje con otras especies simpátricas del mismo 21 género encontrando que esta especie, a la que nombramos como Sporophila iberaensis, 22 habita pastizales húmedos de los bordes de los esteros, presentando un repertorio vocal y un 1 plumaje únicos. Debido a su distribución restringida y las amenazas que tiene su hábitat, 2 esta nueva especie debe ser categorizada como Vulnerable en la lista roja de la IUCN. 3 4 SPOROPHILA IS A Neotropical genus of ca 30 species of small (8-10 g) seedeaters of 1