Alarconia is currently composed of only two poorly studied species. The genus and its type species, A. seaholmi, were originally described based on a single male specimen collected from Acapulco, on the Pacific coast of Mexico. Decades later, specimens belonging to the genus collected in the southwestern Atlantic, in Brazil, led to the description of the second species, A. guinotae. Recently, a series of phylogenetic studies have elucidated the taxonomy of Pinnotheridae, leading to the current classification with three subfamilies. However, the genus Alarconia was not addressed in these studies and its phylogenetic relationships, and consequently its taxonomy, remained poorly understood. Herein, we have used sequence fragments of three genes, the mitochondrial 16S rRNA and 12S rRNA and the nuclear H3, to elucidate the phylogenetic relationships of the genus Alarconia using specimens of A. guinotae. Additionally, we have used morphological data to further discuss the relationship between the two species of Alarconia and their phylogenetic relationships to other pinnotherids. The genus Alarconia was recovered as the sister group of all other pinnotherid subfamilies, thus leading to the elevation of the tribe Alarconiini to the subfamily level, with the name Alarconiinae stat. nov., for which we have proposed a rediagnosis. Additionally, we have redescribed the poorly studied Brazilian species, A. guinotae, further discussing its morphology and relationship to the type species. Lastly, a key to the currently known families and subfamilies of Pinnotheroidea is provided.
Alarconiinae stat. nov., Brazil, Molecular phylogenetics, Pinnotheroidea, Taxonomy
