Phylogeny and biology of Ischrysonychini, Chapuis 1875

Leaf beetles (Coleoptera: Chrysomelidae) form one of the largest beetle families, with most members feeding on living plants. Members of the subfamily Cassidinae often show very colorful patterns, diverse morphology, and many interesting behaviors. The New World tribe Ischyrosonychini Chapuis includes seven genera and 68 species. It is divided into three distinct groups (former tribes Asterizini+Ischyrosonychini+Physonotini). However, synapomorphies uniting these three groups were previously unknown. I conducted a phylogenetic analysis on Cassidinae s. str. to address this problem. A stridulatory file on the vertex in both male and female adults was discovered to represent a synapomorphy for the tribe; stridulation using these files was recorded. The genera Asteriza Chevrolat, Eurypedus Gistel, and Cistudinella Champion are shown to be reciprocally monophyletic and the “physonotine” genera (Enagria Spaeth, Eurypepla Boheman, Physonota Boheman, Platycycla Boheman) are shown to represent a paraphyletic group. Detailed morphological and biological studies were conducted. Larval urogomphi are discussed and a distribution map is provided.