PT - JOURNAL ARTICLE AU - Jamie L. Kostyun AU - Jill C. Preston AU - Leonie C. Moyle TI - Heterochronic Developmental Shifts Underlie Floral Diversity within <em>Jaltomata</em> (Solanaceae) AID - 10.1101/169060 DP - 2017 Jan 01 TA - bioRxiv PG - 169060 4099 - http://biorxiv.org/content/early/2017/07/30/169060.short 4100 - http://biorxiv.org/content/early/2017/07/30/169060.full AB - Background Haeckel and Darwin, respectively, proposed heterochronic shifts during mid to late stages of organismal development as key mechanisms generating phenotypic diversity. To determine whether late heterochronic shifts underlie derived floral morphologies within Jaltomata – a genus with extensive and recently evolved floral diversity – we compared floral development of four diverse species (including an ambiguously ancestral or secondarily derived rotate, two putatively independently evolved campanulate, and a tubular morph) to the ancestral rotate floral form, as well as to an outgroup that shares this ancestral floral morphology.Results We determined that early floral development (&lt;1 mm bud stage) is very similar among all species, but that different mature floral forms are distinguishable by mid-development (3-4 mm stages) due to differential growth acceleration of corolla traits. Floral ontogeny among similar mature forms remains comparable until late stages (&gt;5 mm), followed by species-specific heterochronic shifts in corolla traits.Conclusions Our data suggest shared floral patterning during early-stage development, continued shared patterning or re-use of similar floral developmental pathways at mid-stage development, and distinct heterochronic shifts during late-stage development. Heterochrony thus appears to have been important in the rapid and repeated diversification of Jaltomata flowers.