FIGURE 1. Locality information. 1, Relative position of New Zealand and the Chatham archipelago; 2, The locality on the Chatham Islands where the fossils were found; 3, Stratigraphic column showing the Takatika Grit, from which the fossils were recovered. The stratigraphy is based on the same locality and stratigraphy illustrated in Hollis et al. (2017, figure 3) and also uses information from Consoli et al. (2009, figure 1). Ages, units, and sub-units refer to those specified in Hollis et al. (2017).
FIGURE 2. Axis vertebra (1-6), cervical vertebrae (7-30), pelvis (31-34), caudal vertebrae (35-38), and rib elements (39, 40) referred to Kupoupou stilwelli n. gen. et sp. Axis, NMNZ S.47303 in 1, dorsal; 2, ventral, 3, right lateral; 4, left lateral; 5, cranial; 6, caudal. Cervical vertebra (i), possibly third in vertebral column, NMNZ S.47303 in 7, dorsal; 8, ventral; 9, right lateral; 10, left lateral; 11, cranial; 12, caudal. Cervical vertebra (ii), NMNZ S.47303 in 13, dorsal; 14, ventral; 15, right lateral; 16, left lateral; 17, cranial; 18, caudal. Cervical vertebra (iii), NMNZ S.47303 in 19, dorsal; 20, ventral; 21, right lateral; 22, left lateral; 23, cranial; 24, caudal. Cervical vertebra (iv), NMNZ S.47303 in 25, dorsal; 26, ventral; 27, right lateral; 28, left lateral; 29, cranial; 30, caudal. A partial ischium, from the right side of the pelvis, NMNZ S.47303, 31, dorsal; 32, ventral; 33, medial; 34, right lateral. Caudal vertebra, NMNZ S.47303, 35, cranial and 36, caudal. Caudal vertebra, NMNZ S.47312, interpreted to have been located further caudally in the vertebral column compared to the caudal vertebra in NMNZ S.47303, in 37, cranial and 38, caudal. A left rib, NMNZ S.47303 in 39, lateral and 40 caudal. Abbreviations: ac, ansa costotransversaria; fac, facies articularis caudalis; facr, facies articularis cranialis; fov, fovea at base of processus spinosus; ft, foramen transversarium; fv, foramen vertebrale; iav, incipient projections of the arcus vertebrae; li, lacuna interzygapophysialis; pc, processus costalis; pca, processus caroticus; ps, processus spinosus; pt, processus transversus; pvc, processus ventralis corporis; tc, tuberculum costae; td, torus dorsalis; zca, zygapophysis caudalis; zcr, zygapophysis cranialis. Scale bars equal to 20 mm.
FIGURE 3. Coracoids and scapula referred to Kupoupou stilwelli n. gen. et sp. (1-2, 6-7, 8-9) compared to other Paleocene taxa (3-5). Two left coracoids assigned to K. stilwelli n. gen. et sp., NMNZ S.44729, in 1, ventral and 2, dorsal; and NMNZ S.47308 in 6, ventral and 7, dorsal. Dorsal perspectives of left coracoids of Muriwaimanu tuatahi, CM zfa 34 in 3, and Sequiwaimanu rosieae, CM 2016.6.1 in 4; right omal part coracoid of NMNZ S.47302 (larger Chatham Island form), in 5. Left cranial part scapula referred to K. stilwelli n. gen. et sp. NMNZ S.47339, 8, medial and 9, lateral. Abbreviations: acr, acromion; al, angulus lateralis; am, angulus medialis; ce, crista epimarginalis; coa, collum acrocoracoidei; cos, collum scapulae; cs, cotyla scapularis; csb, crista subcapitalis; fa, facies apicalis; fac, facies articularis clavicularis; fas, facies articularis sternalis; fg, facies glenoidalis (facies articularis humeralis); ic, impressio coracobrachialis; ilaa, insertion for ligamenti acrocoraco-acromiale; ilah, impressio ligamenti acrocoracohumeralis; ilap, insertion for ligamenti acrocoraco-procoracoidale; is, impressio sternocoracoidea; ipsc, tuberculum for the insertion of plica synovialis coracoidea; lacs, insertion for ligamenti acrocoraco-claviculare superficiale; lg, labrum glenoidale (facies articularis humeralis); li, labrum internum; not, notch adjacent to the facies articularis clavicularis; oca, protruding omal extremity of crista acrocoracoidea; pac, processus acrocoracoideus; pcc, processus procoracoideus; plsms, sulcus musculi supracoracoideus; tc, tuberculum coracoideum. Scale bars equal to 20 mm. Note that 5 is a tomographic rendering image. The images in 3.3 and 3.4 are reprinted from Mayr et al. (2018b, fig. 3B, 3A) by permission of the publisher (Taylor & Francis Ltd, http://www.tandfonline.com) and by permission of the Society of Vertebrate Paleontology (http://www.vertpaleo.org).
FIGURE 4. The humeri of Kupoupou stilwelli n. gen. et sp. Left humerus of NMNZ S.47308 in 1, dorsal; 2, caudal; 3, ventral; 4, cranial; 5, distal; 6, proximal. Left humerus of NMNZ S.47339 in 7, dorsal; 8, caudal; 9, ventral; 10, cranial; 11, proximal. Abbreviations: cb, crista bicipitalis (bicipital crest); cd, condylus dorsalis (radial condyle); cdf, crus dorsale fossa; ch, caput humeri (humerus head); cv, condylus ventralis (ulnar condyle); dc, crista deltopectoralis (deltopectoral crest) and insertion of the musculus deltoideus major; dtr, dorsal trochlear ridge; el, insertion for entepicondylar ligament; fpd, fossa pneumotricipitalis dorsalis (secondary tricipital fossa); fpv, fossa pneumotricipitalis ventralis (tricipital fossa); ic, incisura capitis (capital incisura); iic, incisura intercondylaris; imp, impressio musculus pectoralis; itr, intermediate trochlear ridge; mb, fossa musculus brachialis; mcc, attachment scar of musculus coracobrachialis caudalis; mcd, margo caudalis; ms, trochlea for tendon musculi scapulotricipitalis; mcl, margo cranialis; mcr, insertion for musculus coracobrachialis cranialis (impressio coracobrachialis); mh, trochlea for tendon musculus humerotricipitalis; msc, crista musculi supracoracoidei as an accessory insertion site for the tendon of the musculus supracoracoideus, extending distally from the tuberculum dorsale; nf, nutrient foramen; psd, processus supracondylaris dorsalis (dorsal supracondylar tubercle); td, tuberculum dorsale (dorsal tubercle) the attachment site of the musculus deltoideus minor and the principal part of the musculus supracoracoideus; ts, sulcus transversus (transverse sulcus); tv, tuberculum ventrale (ventral tubercle/internal tuberosity); vtr, ventral trochlear ridge. Scale bars equal to 20 mm.
FIGURE 5. Long bones of the forewing of Kupoupou stilwelli n. gen. et sp. Left ulna of NMNZ S.47308 in 1, dorsal; 2, ventral. Left ulna of NMNZ S.47339 in 3, dorsal; 4, ventral. Dorsal view of radii, 5, left NMNZ S.47312; 6, left NMNZ S.47303; 7, right NMNZ S.47303; 8, right NMNZ S.47339. Right radius of NMNZ S.47303 (without suggested eroded extent) in caudal (9), and ventral (10) views. Caudodistal view of left radius of NMNZ S.47303, 11, and Muriwaimanu tuatahi, right radius (mirrored) CM 2009.99.1, 12 . Abbreviations: bl, bony lobe; cd, condylus dorsalis; ch, cotyla humeralis; cv, cotyla ventralis; drp, incisura radialis (depression radialis proximalis); fr, fracture; fur, furrow; jut, edge-like jut on dorsal ulna face; mb, scar for insertion of musculus brachialis; mela, groove for musculus extensor longus alulae; memr, groove for the musculus extensor metacarpi radialis; ms, insertion scar for musculus supinator; nf, nutrient foramen; ol, olecranon; pcd, processus cotylaris dorsalis; tav, tuberculum aponeurosis ventralis; tc, tuberculum carpale; ud, depressio ligamentosa (ulnar depression). Dotted lines represent suggested erosion to respective elements. Scale bars equal to 20 mm. 11 and 12 are not to scale.
FIGURE 6. Images of the distal right-wing elements in NMNZ S.47303 (1-2, 4-17). Distal carpometacarpus in 1, ventral, 2, dorsal, and 4, distal aspects. Left carpometacarpi of Muriwaimanu tuatahi, 3 (CM zfa 34, mirrored, Slack et al., 2006), and Sequiwaimanu rosieae, 5 (CM 2016.6.1, mirrored, Mayr et al., 2018b) are presented for comparison, in ventral aspect. The right proximal manus phalanx of the second digit is shown in 6, dorsal, 7, ventral, 8, caudal, 9, cranial, 10, distal, and 11, proximal views. The right manus phalanx of the third digit is presented in 12, dorsal, 13, ventral, 14, caudal, 15, cranial, 16, distal, and 17, proximal aspects. A left-wing reconstruction of Kupoupou stilwelli n. gen. et. sp. is shown in 18, using mirrored carpometacarpus and phalanges. Scale bars are equal to 20 mm. Abbreviations: ee, eroded end; fad, facies articularis digitalis major; fam, facies articularis metacarpalis; fma, facies articularis digitalis major; fmi, facies articularis digitalis minor; mII, os metacarpale majus (metacarpal II); mIII, os metacarpale minus (metacarpal III); pc, pila cranialis phalangis; pp, proximally directed process; si, sulcus interosseous; sim, spatium intermetacarpale; smd, symphysis metacarpalis distalis.The images in 6.3 and 6.5 are reprinted from Mayr et al. (2018b, fig. 4G, 4F) by permission of the publisher (Taylor & Francis Ltd, http://www.tandfonline.com) and by permission of the Society of Vertebrate Paleontology (http://www.vertpaleo.org).
FIGURE 7. Hindlimb elements. Right femur of Kupoupou stilwelli n. gen. et sp. NMNZ S.47308 in 1, cranial and 2, caudal views. Left distal femur of NMNZ S.47339 in 3, cranial and 4, caudal aspects. Right femur of Sequiwaimanu rosieae in caudal view (holotype, CM 2016.6.1), 5, for comparison. Fragmentary right distal tibiotarsus of NMNZ S.47339 in 6, caudal and 7, cranial aspects, compared to cranial view of right distal tibiotarsus of Waimanu manneringi (holotype, CM zfa 34), 8 . Abbreviations: ce, distal opening of canalis extensorius; cf, caput femoris; cl, condylus lateralis; cm, condylus medialis; cof, collum femoris; csm, crista supracondylaris medialis; ct, crista trochanteris; ctf, crista tibiofibularis; stf, semicondylus tibiofibularis; sf, semicondylus fibularis; epl, epicondylus lateralis; fac, facies articularis antitrochanterica; faf, facies articularis fibularis; fat, facies articularis tibialis; flc, fovea ligamenti capitis; fpo, fossa poplitea; ii, incisura intercondylaris; lcr, linea intermuscularis cranialis; lic, linea intermuscularis caudalis; sic, sulcus intercondylaris; sf, semicondylus fibularis; slf, sulcus fibularis; sp; sulcus patellaris; stf, semicondylus tibiofibularis; tct, trochlea cartilaginis tibialis; tlg, tuberculum musculus gastrocnemialis lateralis. Scale bars equal to 20 mm. The image in 7.5 is reprinted from Mayr et al. (2018b, fig. 11A) by permission of the publisher (Taylor & Francis Ltd, http://www.tandfonline.com) and by permission of the Society of Vertebrate Paleontology (http://www.vertpaleo.org). The image in 7.8 is reprinted from Mayr et al. (2017b, fig. 2j), which was published under a Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).
FIGURE 8. Tarsometatarsus of Kupoupou stilwelli n. gen. et sp. compared to other fossil taxa. Tarsometatarsi in dorsal aspect, 1, Paleocene Waimanu manneringi, right (mirrored), holotype CM zfa 35; 2, Paleocene Kupoupou stilwelli n. gen. et sp. left, NMNZ S.47312, 3, Eocene Delphinornis larseni, left, IB/P/B-0062. Left tarsometatarsus of NMNZ S.47312 in 4, distal, 5, proximal, 6, lateral, 7, plantar, and 8, medial views. Abbreviations: ait, area intercotylaris; cl, cotyla lateralis; cl(fdl), crista lateralis flexoris digitorum longus; cl(fhl), crista lateralis flexoris hallucis longus; clh, crista lateralis hypotarsi; cm, cotyla medialis; cm(fdl), crista medialis flexoris digitorum longus; eit, eminentia intercotylaris; fbl, sulcus for muscularis fibularis longus; fcdq, fovea ligamentae collateralis digitorum quarti; fdl, sulcus for tendon of musculus flexor digitorum longus; fhl, sulcus for tendon of musculus flexor hallucis longus; fid, fossa intercotylaris dorsalis; fidm, fossa intercotylaris dorsalis medialis; fphl, fossa parahypotarsalis lateralis; fphm, fossa parahypotarsalis medialis; fsp, fossa supratrochlearis plantaris; fvd, foramen vasculare distale; fvpl, foramen vasculare proximale laterale; fvpm, foramen vasculare proximale laterale; iim, incisura intertrochlearis medialis; ilcl, impressio ligamentosae collaterale laterale intertarsi; ilcm, impressio ligamentosae collaterale mediale intertarsi; ilcma, impressio ligamentosae collaterale mediale intertarsi accessorium; irel, impressiones retinaculi extensorii lateralis; irem, impressiones retinaculi extensorii medialis; madII, insertion site of musculus adductor digiti II; madIV, insertion site of musculus adductor digiti IV; sf, sulcus flexorius; sldl, sulcus longitudinalis dorsalis lateralis; sldm, sulcus longitudinalis dorsalis medialis; slg, sulcus ligamentosus; tII, trochlea metatarsi II; tIII, trochlea metatarsi III; tIV, trochlea metatarsi IV; tfb, tuberculum muscularis fibularis brevis; tmtc, tuberositas muscularis tibialis cranialis. Scale bars equal to 20 mm.
FIGURE 9. Views of the caudal end left mandible of NMNZ S.47302. 1, dorsal; 2 . ventral; 3, rostral; 4, caudal; 5, left lateral; 6, left medial aspects. Reconstruction assuming proportions similar to Paleocene penguins in 7, in left lateral view. Abbreviations: cc, cotyla caudalis; cl, cotyla lateralis; cm, cotyla medialis; facm, fossa aditus canalis mandibulae; fmc, fenestra mandibulae caudalis; mp, insertion of musculus pterygoideus; pc, processus coronoideus; plm, processes lateralis mandibulae; pmm, processus mandibulae medialis; pr, processus retroarticularis; si, sulcus intercotylaris. Scale bars equal to 20 mm.
FIGURE 10. Cervical vertebra IV (1 - 6), coracoid (7 - 10), and furcula (11 - 16) of NMNZ S.47302, as part of the larger Chatham Island form. Cervical vertebra IV in 1, dorsal; 2, ventral; 3, right lateral; 4, left lateral; 5, cranial; 6; caudal. Omal right coracoid in 7, dorsal; 8, ventral; 9, medial; 10, lateral. Partial furcula in 11, caudal; 12, cranial; 13, right lateral; 14, left lateral; 15, dorsal; 16, ventral. Abbreviations: cs, cotyla scapularis; esc, extremitas sternalis claviculae; fac, facies articularis clavicularis; faca, facies articularis caudalis; facr, facies articularis cranialis; fg, facies glenoidalis (facies articularis humeralis); fo, fossa (see text); ft, foramen transversarium; ic, impressio coracobrachialis; ilaa, impressio ligamenti acrocoraco-acromiale; ilah, impressio ligamenti acrocoracohumeralis; ipsc, tuberculum for insertion of plica synovialis coracoidea; lg, labrum glenoidale (facies articularis humeralis); pc, processus costalis; pca, processus caroticus; pcc, processus procoracoideus; ps, processus spinosus; pvc, processus ventralis corporis; td, torus dorsalis; zca, zygapophysis caudalis; zcr, zygapophysis cranialis. Scale bars equal to 20 mm.
FIGURE 11. Partial sternum of NMNZ S.47302, of the larger Chatham Island form. Dorsal, 1; ventral, 2; right lateral, 3; left lateral, 4; cranial, 5; caudal, 6 . Abbreviations: cs, carina sterni; fp, foramen pneumaticum; se, spina externa. Scale bar equals 20 mm.
FIGURE 12. Humeri of sphenisciforms from the Chatham Island, compared to those of various early penguins. Right humerus NMNZ S.47304 of unnamed large form in 1, dorsal, 2, ventral. Humeri in ventral aspect, left Sequiwaimanu rosieae, CM 2016.6.1, 3; left Kupoupou stilwelli n. gen. et sp. NMNZ S.47308, 4; left K. stilwelli n. gen. et sp., NMNZ S.47339, 5; right Muriwaimanu tuatahi, CM zfa 34, 6; right M. tuatahi, 2008.145.4, 7; right M. tuatahi, 2008.145.3, 8; left M. tuatahi, 2008.145.4, 9; right M. tuatahi, CM 2010.108.3, 10; left Kaiika maxwelli, OU 22402, 11 . Abbreviations: cb, crista bicipitalis (bicipital crest); cd, condylus dorsalis (radial condyle); ch, caput humeri (humerus head); cv, condylus ventralis (ulnar condyle); dc, crista deltopectoralis (deltopectoral crest) and attachment site for musculus propatagialis (dorsally) and musculus pectoralis; fpd, fossa pneumotricipitalis dorsalis (secondary tricipital fossa); fpv, fossa pneumotricipitalis ventralis (tricipital fossa); ic, incisura capitis (capital incisura); imp, impressio musculus pectoralis, particularly for insertion of musculus pectoralis thoracica; itr, intermediate trochlear ridge; mcc, attachment scar of musculus coracobrachialis caudalis; ms, trochlea for tendon musculus scapulotricipitalis; mcr, insertion for musculus coracobrachialis cranialis; mh, trochlea for tendon musculus humerotricipitalis; msc, crista musculi supracoracoidei as an accessory insertion site for the tendon of the musculus supracoracoideus, extending distally from the tuberculum dorsale; psd, processus supracondylaris dorsalis (dorsal supracondylar tubercle); td, tuberculum dorsale (dorsal tubercle) and attachment site of musculus deltoideus minor and the principal part of the musculus supracoracoideus; ts, sulcus transversus (transverse sulcus); tv, tuberculum ventrale (ventral tubercle/internal tuberosity); vtr, ventral trochlear ridge. Scale bar equal to 20 mm. The image in 12.3 is reprinted from Mayr et al. (2018b, fig. 4C) by permission of the publisher (Taylor & Francis Ltd, http://www.tandfonline.com) and by permission of the Society of Vertebrate Paleontology (http://www.vertpaleo.org).
FIGURE 13. Parsimony majority-rule (50%) consensus tree of 16,300 MPTs (length = 5,234). Percentage of MPTs recovering each node is indicated at each internode in the consensus tree, and bootstrap support values (over 40% only) are numbered below them italicised in red. Legend and branch colouration correspond to percentage of MPTs that recovered each node. Darkened area indicates the topological region occupied by Paleocene taxa. Ages associated with taxa are shown in thickened black lines, the references of which are given in Appendix 1. Nodes illustrated are not calibrated in association with age.
FIGURE 14. Phylogenetic tree based on Bayesian inference (majority-rule consensus, undated). Colour of branches indicate the gradient of posterior probability values (see legend), the numbers of which are specified next to their respective branches. Darkened area at base of Sphenisciformes indicates the topological region occupied by Paleocene taxa. Scale bar corresponds to the given degree of change across branch lengths.
FIGURE 15. A south polar orthographic projection of the Earth around 60 Ma. Approximate site locations of Paleocene penguin fossils are indicated. Locations are associated with following fossils: CANTERBURY, Waipara Greensand = Waimanu manneringi, Muriwaimanu tuatahi (Slack et al., 2006), Sequiwaimanu rosieae (Mayr et al., 2018b), giant Waipara Greensand penguin (Mayr et al., 2017a), ?Crossvallia waiparensis (Mayr et al., 2019); OTAGO, Moeraki Formation = Kumimanu biceae (Mayr et al., 2017b); CHATHAM ISLAND, Takatika Grit = Kupoupou stilwelli n. gen. et sp. and larger Chatham Island form; SEYMOUR ISLAND, Cross Valley Formation = Crossvallia unienwillia (Tambussi et al., 2005; Jadwiszczak et al., 2013). Adapted from palaeogeographic maps of the PALEOMAP PaleoAtlas for GPlates (Scotese, 2002; 2016), used with permission. Reconstruction was implemented using GPlates 2.0 software .
