DOI: 10.5061/dryad.9w0vt4bq2
title: Data from: Tactile bill-tip organs in seabirds suggests conservation of a deep avian symplesiomorphy

description: Birds’ bills are their main tactile interface with the outside world.
 Tactile bill-tip organs associated with specialised foraging techniques
 are present in several bird groups, yet remain understudied in most
 clades. One example is Austrodyptornithes, the major seabird clade uniting
 Procellariiformes (albatrosses and petrels) and Sphenisciformes
 (penguins). Here, we describe the mechanoreceptor arrangement and
 neurovascular anatomy in the premaxillae of Austrodyptornithes. Using a
 wide phylogenetic sample of extant birds (361 species), we show that
 albatrosses and penguins exhibit complex tactile bill-tip anatomies,
 comparable to birds with known bill-tip organs, despite not being known to
 use tactile foraging. Petrels (Procellariidae, Hydrobatidae and
 Oceanitidae) lack these morphologies, indicating an evolutionary
 transition in bill-tip mechanosensitivity within Procellariiformes. The
 bill-tip organ in Austrodyptornithes may be functionally related to
 nocturnal foraging and prey detection under water, or courtship displays
 involving tactile stimulation of the bill. Alternatively, these organs may
 be vestigial, as is likely the case in most palaeognaths (e.g., ostriches
 and emu). Ancestral state reconstructions fail to reject the hypothesis
 that the last common ancestor of Austrodyptornithes had a bill-tip organ;
 thus, tactile-foraging may be ancestral for this major extant clade,
 perhaps retained from a deeper point in crown bird evolutionary history.
description: # Data from: Tactile bill-tip organs in seabirds suggests conservation of
 a deep avian symplesiomorphy
 [https://doi.org/10.5061/dryad.9w0vt4bq2](https://doi.org/10.5061/dryad.9w0vt4bq2) This is the data and R code supporting our publication. Data were collected from museum specimens of bird skulls from photographs, in order to assess the presence of tactile neurovascular structures in the beaks of Austrodyptornithine seabirds in relation to all extant birds.  ## Description of the data and file structure The R script requires the latest version of RStudio to run, all packages required are listed in the script at the start. All datasets (as .csv files) are utilized by the R script "seabird beaks code.R". The script will import the necessary data, so long as the files are all saved in the same directory.  The species_tree.tre file is the time-scaled phylogeny used, based on two previously published trees (see methods section of paper for details):  1. Cooney CR, Bright JA, Capp EJR, Chira AM, Hughes EC, Moody CJA, Nouri LO, Varley ZK, Thomas GH. 2017 Mega-evolutionary dynamics of the adaptive radiation of birds. *Nature* **542**, 344–347(doi:10.1038/nature21074) 2. Prum RO, Berv JS, Dornburg A, Field DJ, Townsend JP, Lemmon EM, Lemmon AR. 2015 A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing. *Nature* **526**, 569–573. (doi:10.1038/nature15697 Measurements were taken from photographs of the premaxillary bones. The majority of these are part of a previous dataset, and the photographs are freely available on the Smithsonian digital collections database (search by specimen number, which can be found in Table S1 of the SI accompanying the manuscript): [https://collections.nmnh.si.edu/search/birds/](https://collections.nmnh.si.edu/search/birds/)  The remaining specimen photographs (specimens from other museums) have been included here in a ZIP folder. Meshes of the micro-CT scans used to visualize and describe the internal soft tissue morphology of the beaks of five key species of birds are also uploaded here  as a separate ZIP file. ## Abbreviations/Column headings & file names: labels FS1.csv - updated species names of birds used to label species level phylogeny tips * "x" old species name * "o" updated species name * "i" label formatted as required for *phytools*  node matches.csv - corresponding nodes between species and collapsed phylogenies, with ancestral state estimates (from species level phylogeny) used to plot collapsed tree and phylomorphospace * "Small tree" node number on collapsed tree (Figure 2a) * "Big tree" node number on species level tree (Figure S2) * "Num pits" ancestral state estimate for node: number of sensory pits on ventral surface of premaxilla * "Log pits" ancestral state estimate for node: log(number of sensory pits on ventral surface of premaxilla) * "NND" ancestral state estimate for node: average nearest neighbour distance between pits (mm) Small tree tips.csv - collapsed tree tip values (averages for clades) used to plot collapsed tree and phylomorphospace * "Pits" number of sensory pits on ventral surface of premaxilla * "Log" log(number of sensory pits on ventral surface of premaxilla) * "Pitslength" number of sensory pits on ventral surface of premaxilla / length of beak (mm) * "LogPL" log(number of sensory pits on ventral surface of premaxilla / length of beak) * "NND" average nearest neighbour distance between pits (mm) Spp with pits NND.csv - tip values for species level tree * "Mx pits" number of sensory pits on ventral surface of premaxilla * "Pitsforlog" transformation of "Mx pits" where number of pits = 0 (as cannot be log transformed) - 0 values adjusted to 1 * "Logpits" log(Pitsforlog) * "NND" average nearest neighbour distance between pits (mm) Ventral pits ALB.csv - species level data, used for boxplots (Figure S1) * "Species", "Family", "Order" taxonomic groups/labels * "Category" groups of tactile bill-tip organs & phylogenies used as categories for boxplot and Mann-Whitney tests * "Mx ventral" number of sensory pits on ventral surface of premaxilla * "MXVFORLOG" transformation of "Mx ventral" where number of pits = 0 (as cannot be log transformed) - 0 values adjusted to 1 * "Log Mx ventral" log(MXVFORLOG) * "NND" average nearest neighbour distance between pits (mm) [where cells are left blank, there were no pits, and thus distance between the pits could not be measured]