Tactile bill-tip organs in seabirds suggest conservation of a deep avian symplesiomorphy

<jats:p>Birds’ bills are their main tactile interface with the outside world. Tactile bill-tip organs associated with specialized foraging techniques are present in several bird groups, yet remain understudied in most clades. One example is Austrodyptornithes, the major seabird clade u...

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Main Authors: du Toit, CJ, Bond, AL, Cunningham, SJ, Field, DJ, Portugal, SJ
Format: Journal article
Language:English
Published: Royal Society 2024
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author du Toit, CJ
Bond, AL
Cunningham, SJ
Field, DJ
Portugal, SJ
author_facet du Toit, CJ
Bond, AL
Cunningham, SJ
Field, DJ
Portugal, SJ
author_sort du Toit, CJ
collection OXFORD
description <jats:p>Birds’ bills are their main tactile interface with the outside world. Tactile bill-tip organs associated with specialized 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.</jats:p>
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spelling oxford-uuid:8dbb4625-df4a-459a-8b83-d055a5df6b702024-09-18T10:19:22ZTactile bill-tip organs in seabirds suggest conservation of a deep avian symplesiomorphyJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:8dbb4625-df4a-459a-8b83-d055a5df6b70EnglishSymplectic ElementsRoyal Society2024du Toit, CJBond, ALCunningham, SJField, DJPortugal, SJ<jats:p>Birds’ bills are their main tactile interface with the outside world. Tactile bill-tip organs associated with specialized 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.</jats:p>
spellingShingle du Toit, CJ
Bond, AL
Cunningham, SJ
Field, DJ
Portugal, SJ
Tactile bill-tip organs in seabirds suggest conservation of a deep avian symplesiomorphy
title Tactile bill-tip organs in seabirds suggest conservation of a deep avian symplesiomorphy
title_full Tactile bill-tip organs in seabirds suggest conservation of a deep avian symplesiomorphy
title_fullStr Tactile bill-tip organs in seabirds suggest conservation of a deep avian symplesiomorphy
title_full_unstemmed Tactile bill-tip organs in seabirds suggest conservation of a deep avian symplesiomorphy
title_short Tactile bill-tip organs in seabirds suggest conservation of a deep avian symplesiomorphy
title_sort tactile bill tip organs in seabirds suggest conservation of a deep avian symplesiomorphy
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AT bondal tactilebilltiporgansinseabirdssuggestconservationofadeepaviansymplesiomorphy
AT cunninghamsj tactilebilltiporgansinseabirdssuggestconservationofadeepaviansymplesiomorphy
AT fielddj tactilebilltiporgansinseabirdssuggestconservationofadeepaviansymplesiomorphy
AT portugalsj tactilebilltiporgansinseabirdssuggestconservationofadeepaviansymplesiomorphy