DOI: 10.5061/dryad.hb6b0
title: Data from: Extremely fast feeding strikes are powered by elastic recoil in a seahorse relative, the snipefish, Macroramphosus scolopax

description: Among over 30,000 species of ray-finned fishes, seahorses and pipefishes
 have a unique feeding mechanism whereby the elastic recoil of tendons
 allows them to rotate their long snouts extremely rapidly in order to
 capture small elusive prey. To understand the evolutionary origins of this
 feeding mechanism, its phylogenetic distribution among closely related
 lineages must be assessed. We present evidence for elastic recoil powered
 feeding in the snipefish (Macroramphosus scolopax) from kinematics,
 dynamics, and morphology. High-speed videos of strikes show they achieve
 extremely fast head and hyoid rotational velocities, resulting in rapid
 prey capture in as short at 2 ms. The maximum instantaneous
 muscle-mass-specific power requirement for head rotation in snipefish was
 above the known vertebrate maximum, which is evidence that strikes are not
 the result of direct muscle power. Finally, we show that the over-center
 conformation of the four-bar linkage mechanism coupling head elevation to
 hyoid rotation in snipefish can function as a torque reversal latch,
 preventing the head from rotating and providing the opportunity for
 elastic energy storage. The presence of elastic recoil feeding in
 snipefish means that this high-performance mechanism is not restricted to
 the Syngnathidae (seahorses and pipefish) and may have evolved in
 parallel.
description: R scripts for kinematics
 and power calculationsThis zip file includes
 scripts used to calculating kinematic variables and calculating muscle
 mass specific power requirements from high speed videos and morphological
 measurementsLongoGoodearlyWainwright_scripts.zipHigh speed video exampleExample high speed video of a snipefish feeding strike. Strike was filmed at 2000 fps and is played back at 30 fps.Example_video_scolopax9_15_30fps.aviFourbar_relative_linkage_lengths_from_videosRelative linkage lengths and other variables calculated from high speed video for four-bar linkage mechanism in snipefish. Each file represents one feeding sequence, which each row representing variables calculated for a single frame in the video. README file explains the column headers.Output from power requirement calculationsThis zip file contains the output for each feeding sequence from calculations of muscle mass specific power requirements and related variables (rotational velocities, accelerations, energy, etc). KINE files are each from a different feeding sequence, where rows are variables calculated at that frame. snipefishOutputSummary_forFig2 contains the aggregated information for peak instantaneous muscle mass specific power requirement. README explains all column headings.PowerRequirement_output.zipSnipefish_hyoidPectoral_muscles_microCTmovieThis zipped files includes a video highlighting some of the muscles associated with the pectoral girdle, hyoid, and urohyal. This video was created from a micro-CT scan and shows sections through a volume rendering of a snipefish with the suspensorium adducted (as in Figure 3A, B, and D). Two annotated still are included to help identify structures of interest and provide orientation.