Phylogeny of the mayfly family Leptohyphidae (Insecta: Ephemeroptera) in South America

Abstract

A cladistic analysis of the South American members of the family Leptohyphidae is presented. A matrix of 73 taxa and 124 morphological characters was analyzed under two distinct weighting criteria (implied weighting, which weights characters as a whole, and self-weighted optimization, which differentially weights character state transformations). To assess the monophyly of the Leptohyphidae, some representatives of Ephemerellidae, Ephemerythidae, Machadorythidae, Teloganodidae, Tricorythidae, Coryphoridae, and Melanemerellidae, were also included. Trees were rooted in Ephemerellidae. Conspicuous differences in consensus topology occur when transformation costs among character states are weighted (including asymmetries). The differences in the assessments of character reliability in the two weighting criteria used are discussed. In many cases, self weighting, in allowing for asymmetries in transformation costs, considered many of the character state transformations as more reliable (=informative) than implied weights (which needlessly down-weighted the whole character). The results confirm the monophyly of Leptohyphidae and support its sister group relationship with Coryphoridae. Higher classification of the Ephemerelloidea is briefly discussed. Shortest trees do not support the recently proposed division of Leptohyphidae in two subfamilies.