Table 1.
Specimen numbers of skeletal specimens used for comparison during fossil description and phylogenetic analyses.
Fig 1.
Photograph (A) and line drawing (B) of the holotype specimen of Paakniwatavis grandei (FMNH PA725).
Extremely crushed bone and bone margin is delimited with dashed margins. Anatomical abbreviations: prx, premaxilla; orb, orbital margin; mnd, mandible; cvt, cervical vertebrae; tvt, thoracic vertebrae; syn, synsacrum; pyg, pygostyle; cor, coracoid; scp, scapula; fur, furcula; str, sternum; rbs, ribs; hum, humerus; uln, ulna; rad, radius; rde, radiale; cmc, carpometacarpus; mII:1, phalanx 1 of manual digit II; mtII:2, phalanx 2 of manual digit II; ili, ilium; fem, femur; tbt, tibiotarsus; tmt, tarsometatarsus; mtI, metatarsal I; I:1, phalanx 1 of pedal digit I; II:1, phalanx 1 of pedal digit II; III:1, phalanx 1 of pedal digit III; IV:1, phalanx 1 of pedal digit IV.
Fig 2.
Photograph (A) and line drawing (B) of the holotype specimen of Paakniwatavis grandei (FMNH PA725).
Bone is unfilled. Extremely crushed bone and bone margin is delimited with dashed margins. Anatomical abbreviations: prx, premaxilla; max, maxilla; jug, jugal; orb, orbital margin; rmf, rostral mandibular fenestra; scl, scleral ossicles; mnd, mandible; rde, radiale; cmc, carpometacarpus.
Table 2.
Selected measurements of Paakniwatavis grandei in millimeters (mm), taken from surface of the holotype specimen slab (left/right) compared with taken and previously published measurements of Presbyornis [22,52], Telmabates antiquus [48], and Nettapterornis oxfordi [54].
Pedal phalanges are described using the format (digit:phalanx). Measurements are given for holotype specimens only.
Fig 3.
Comparison of anseriform traits in Paakniwatavis grandei (FMNH PA725) to those of the extinct Presbyornis and extant Anseriformes (Chauna 21orquate, Anseranas semipalmata, and Chloephaga melanoptera).
Photograph (A) and CT scan slice (B) of the holotype specimen of P. grandei (FMNH PA725), with close-ups (B1 and B2) of CT scan slices of the caudal mandible. Photographs of the skull and mandible of (C) C. 21orquate, (D) A. semipalmata, I C. melanoptera, and (F) Presbyornis sp. (USNM 299846). Photograph (G) and CT scan slice (G1) of the left tarsometatarsus and pedal phalanges of P. grandei. Photographs of (H) the left tarsometatarsus and pedal phalanges of Presbyornis sp. (USNM ACC 335940) and (I) the right tarsometatarsus and pedal phalanges of 21orquateata. Photographs of the furcula of (J) 21orquateata, (K) A. semipalmata, (L) Anas platyrhynchos, and (M) Presbyornis sp. (USNM ACC335940). Photograph (N) and CT scan slice (O) of the furcula of P. grandei from the holotype specimen. Anatomical abbreviations: prx, premaxilla; orb, orbital margin; mnd, mandible; rta, retroarticular process; rde, radiale; cmc, carpometacarpus; sym, symphysis; tmt, tarsometatarsus; I:1, phalanx 1 of pedal digit I; II:1, phalanx 1 of pedal digit II; III:1, phalanx 1 of pedal digit III; III:2, phalanx 2 of pedal digit III; IV:1, phalanx 1 of pedal digit IV.
Fig 4.
Comparison of the coracoid and hypotarsus of the tarsometatarsus of Paakniwatavis grandei (FMNH PA725) to that of the extinct Presbyornis, Telmabates antiquus, Chaunoides antiquus and Nettapterornis oxfordi and extant Anseriformes.
Line drawings of the coracoids and hypotarsi of (A) Anhima cornuta, (B) C. antiquus, (C) Anseranas semipalmata, (D) Dendrocygna guttata, (E) Presbyornis sp., (F) P. grandei, (G) T. antiquus and (H) A. oxfordi. Coracoids are depicted in dorsal aspect, hypotarsi are depicted in proximal and plantar aspects. L and M in panel (A) denote the lateral and medial sides of each element. (F1 and F2) are segmented hypotarsi of the left tarsometatarsus of P. grandei in lateroplantar aspect. (F3 and F4) are CT scan slices of the same tarsometatarsus of P. grandei. Anatomical abbreviations: acr, processus acrocoracoideus; hmf, humeral facet; sct, scapular facet; prc, procoracoid process; fns, supracoracoid nerve foramen; pno, pneumatic opening; lpr, lateral process; mpr, medial process; mhc, medial hypotarsal crest; 1, sulcus for tendon of musculus flexor hallucis longus (fhl); 2, sulcus or canal for tendon of musculus flexor digitorum longus (fdl); 3, sulcus for tendon of musculus flexor perforatus digiti 2 (fp2); 4, sulcus for tendon of musculus flexor perforans et perforatus digiti 2 (fpp2); 5, sulcus for muscularus fibularis longus (fbl).
Fig 5.
Resulting consensus tree from Bayesian analysis of 719 morphological characters and 158,368 base pairs.
Clade credibility values greater than 50% are annotated above branches. Extinct taxa are delimited with daggers. A line drawing of the holotype specimen of Paakniwatavis grandei is overlaid on the tree and a reconstruction of this species is shown to the right of the tree. Icons represent definitive ancestral state reconstruction of the earliest transitions. Only the first major transitions for Anseriformes are shown, with subsequent transitions excluded. The insert to the right of the tree displays how results changed when Wilaru was included in analysis.