Developmental growth patterns of the filter-feeder pterosaur, Pterodaustro guinazui

A. CHINSAMY, L. CODORNIÚ AND L. CHIAPPE

Biology Letters

Royal Society

Lugar: London ; Año: 2008 p. 1 - 4

Life history parameters of pterosaurs such as, growth and ontogenetic development represent an enigma.  This aspect of pterosaur biology has remained perplexing because only two taxa, Pterodaustro guinazui and Pterodactylus kochi, are represented by a complete ontogenetic series i.e., from hatchling to adult.  The Pterodaustro sample studied here is unique in that besides being represented by hundreds of individuals with wing spans ranging from 0.3 to 3m, it also includes an embryo within an egg1.  Here we present the first comprehensive osteohistological assessment of multiple skeletal elements representing a range of ontogenetic sizes of a single pterosaur species.  Our analysis of bone microstructure gives unparalleled insight into developmental patterns hitherto unknown in pterosaurs.  We show that upon hatching, Pterodaustro juveniles grew rapidly for about 2 years until they reached approximately 53% of their mature body size, whereupon they attained sexual maturity.  Thereafter, growth continued for at least another 3-4 years at comparatively slower rates until larger adult body sizes were attained.  Clear evidence of diaphyseal and epiphyseal termination of growth permits the deduction that Pterodaustro had a determinate growth strategy.