DOI: 10.5061/dryad.h6289
title: Data from: When conifers took flight: A biomechanical evaluation of an imperfect evolutionary takeoff

description: Manifera talaris, a voltzian conifer from the late early to middle Permian
 (ca. 270 Ma) of Texas, is the earliest known conifer to produce winged
 seeds indicative of autorotating flight. In contrast to autorotating seeds
 and fruits of extant plants, the ones of M. talaris are exceptional in
 that they have variable morphology. They bore two wings that produced a
 range of wing configurations, from seeds with two equal-sized wings to
 single-winged specimens, via various stages of underdevelopment of one of
 the wings. To examine the effects of various seed morphologies on
 aerodynamics and dispersal potential, we studied the flight performance of
 paper models of three morphotypes: symmetric double-winged, asymmetric
 double-winged, and single-winged. Using a high-speed camera we identified
 the mode of descent (plummeting, gliding, autorotation) and quantified
 descent speed, autorotation frequency, and other flight characteristics.
 To validate such modeling as an inferential tool, we compared descent of
 extant analogues (kauri; Agathis australis) with descent of similarly
 constructed seed models. All three seed morphotypes exhibited autorotating
 flight behavior. However, double-winged seeds, especially symmetric ones,
 failed to initiate slow autorotative descent more frequently than
 single-winged seeds. Even when autorotating, symmetric double-winged seeds
 descend faster than asymmetric double-winged ones, and descent is roughly
 twice as fast compared to single-winged seeds. Moreover, the relative
 advantage that (effectively) single-winged seeds have in slowing descent
 during autorotation becomes larger as seed weight increases. Hence, the
 range in seed wing configurations in M. talaris produced a wide variation
 in potential dispersal capacity. Overall, our results indicate that the
 evolutionarily novel autorotating winged seeds must have improved conifer
 seed dispersal, in a time when animal vectors for dispersion were
 virtually absent. Because of the range in wing configuration, the early
 evolution of autorotative flight in conifers was a functionally imperfect
 one, which provides us insight into the evolutionary developmental biology
 of autorotative seeds in conifers.
description: Nondimensional
 aerodynamic parameters versus disk loadingNondimensional
 aerodynamic parameters versus disk loading (eq. 3) for all autorotative
 descents of Manifera talaris models and Agathis australis models and
 seeds. A, Reynolds number (Re, eq. 1). B, Advance ratio (J, eq. 2). C,
 Effective lift coefficient (CL,eff, eq. 7). D, Effective drag coefficient
 (CD,eff, eq. 6).Figure_S1.pdfKinematic changes with increased massKinematic changes with increased mass. A, Vertical component of aerodynamic forces balances weight, while the lateral component provides for the centripetal acceleration of the spinning seed. B, As mass increases, the autorotation frequency f1R increases and the coning angle (β) reduces. These changes result in a more vertically oriented and larger aerodynamic force to balance the increased weight, allowing the descent speed V to remain nearly constant.Figure_S2.pdfLaser cutter source file for winged seed modelsLaser cutter (.ai) source file for winged seed models.FileS3.aiLaser cutter source file for adhesive polyester film weights used in ballastingLaser cutter (.ai) source file for adhesive polyester film weights used in ballasting.FileS4.aiRepresentative autorotative descent in a Manifera talaris single-winged modelRepresentative autorotative descent in a Manifera talaris single-winged model, filmed at 500 fps, model is 9.5 mg.FileS5.mov