Evolution of macroglands and defensive mechanisms in Leiuperinae (Anura: Leptodactylidae)

FERRARO, DAIANA PAOLA; PEREYRA, MARTÍN OSCAR; TOPA, PASCUAL EMILIO; FAIVOVICH, JULIÁN

ZOOLOGICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020

0024-4082

Anurans show a wide variety of anti-predator mechanisms, and the species of the Neotropical clade Leiuperinae display several of them. Most species of Edalorhina, Physalaemus, and Pleurodema show eyespots, hidden bright colours, macroglands in inguinal/lumbar position, defensive behaviours, and/or chemical defence. We conducted a histological analysis of dorsal and lumbar skin and revised colour patterns, defensive behaviours, and glandular secretions to study the diversity and evolution of anti-predator mechanisms associated with macroglands. We described seventeen characters and optimized them in a phylogenetic hypothesis of Leiuperinae. In the most recent common ancestor of Edalorhina + Engystomops + Physalaemus + Pleurodema a particular type of serous glands (the main component of macroglands) evolved in the lumbar skin, along with the absence of the Eberth-Katschenko layer. A defensive behaviour observed in leiuperines with macroglands includes four displays (?crouching down? behaviour, rear elevation, body inflation, and eye-protection), all present in the same ancestor. The two elements associated with aposematism (hidden bright colours and eyespots) evolved independently in several species. Our results provide phylogenetic evidence for the startle-first hypothesis, which suggests that behavioural displays arise as sudden movements in camouflaged individuals to avoid predatory attacks, before the origin of bright colouration.