On the presence of the patella in frogs

ABDALA V; VERA MC; PONSSA ML

ANATOMICAL RECORD-ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Lugar: West Sussex; Año: 2017 vol. 300 p. 1747 - 1755

1932-8486

The patella is one of the most studied sesamoids. Historically, the patella is described as a big bone embedded in the tendon of the quadriceps femoris muscle. This sesamoid is studied from developmental, functional, clinical and anatomical perspectives. The presence of a patella is reported in squamatans, birds and mammals.Lissamphibians are identified as the major linage that fail to develop a patella. However, this sesamoid is reported at least one time in anurans, but without detailed anatomical discussions. Through anatomical and histologicalstudies we examined the topography and tissue composition of two structures that we identify as the proximal and distal patellae in several anuran species. We explored the evolution of these sesamoids through ancestral statereconstruction, finding that they are ancestral for amphibians and possibly tetrapods as a whole. The presence of these patellae in anurans would roll back their origin to the last common ancestor of tetrapods. From a functional perspective, the overwhelming evidence of fibrocartilage as a clear response to compression suggests that the fibrocartilaginous patellae could also withstand the mechanical stress generated on the knee during jumping.