Fig 1.
Specimen completeness among reported hesperornithiforms.
The number of specimens preserving fewer than three elements (black) and three elements or more (red) are shown for all described hesperornithiform taxa. A schematic reconstruction of UNSM 20030 is shown with the preserved elements shaded dark gray. It should be noted that the exact rib placement is not known and was estimated for the figure. References for hesperornithiform taxa are as follows: Baptornis advenus [11, 6]; Asiahesperornis bazhanovi [25]; Brodavis [26]; Canadaga arctica [17, 27]; Enaliornis [28]; Hesperornis crassipes, H. gracilis [11]; H. bairdi, H. chowi, H. macdonaldi, H. mengeli [29]; H. regalis [11, 30–31]; H. rossicus [32]; Judinornis nogontsavensis [33]; Parahesperornis alexi [15]; Pasquiaornis spp. [34–36]; Potamornis skutchi [37].
Fig 2.
Phylogenetic analysis of Bell and Chiappe (2015) showing the derived placement of Fumicollis hoffmani within the Hesperornithiformes (grey box).
Time calibration is based on reported ages of known fossils. Body silhouettes are shown to represent approximate size differences among hesperornithiforms, scaled to a 6 foot human (lower right) based on geometric scaling of the tarsometatarsi and femora of known specimens. Node A is united by five unambiguous synapomorphies (see [8] for details). Abbreviations: ALB, Albian; CEN, Cenomanian; CMP, Campanian; CON, Coniacian; MAA, Maastrichtian; SNT, Santonian; TUR, Turonian.
Fig 3.
Features of the right tarsometatarsus of UNSM 20030 that were identified by a phylogenetic analysis (see [8]) as uniting Fumicollis hoffmani, Parahesperornis, and Hesperornis in a clade.
A, well-developed depression (d) on the lateral face of the proximal end of metatarsal IV; B, prominent grooves (g) separating the metatarsals along the entire length of shaft and ridge (r) that forms the dorsal surface of metatarsal IV; C, the enclosed distal vascular foramen (df) between the trochlea of metatarsals III and IV is tear-drop shaped in plantar view (note the trochleae of the specimen have been labelled incorrectly); D, metatarsals IV, III, and II progressively displaced plantarly (shingled; displacement shown with arrows); and E, shaft of metatarsal IV is widest at midshaft and tapers at both the proximal and distal ends (widths indicated with arrows). Abbreviations: d, depression; df, distal foramen; g, groove; r, ridge; II–IV, metatarsal II–IV.
Table 1.
Selected measurements of the presacral vertebrae of UNSM 20030.
All measurements are in millimeters. Asterisk indicates approximate measurement.
Fig 4.
Photographs and interpretative drawings of presacral vertebrae 16 (A) and 17 (B) of UNSM 20030 in dorsal (1), cranial (2), lateral (3), caudal (4), and ventral (5) views.
Abbreviations: ca, caudal articular surface; cf, costal fovea; cr, cranial articular surface; lc, lateral concavity; ns, neural spine; poz, postzygapophysis; prz, prezygapophysis; tp, transverse process; vp, ventral process.
Fig 5.
Photographs and interpretative drawings of presacral vertebrae 18 (A) and 19 (B) of UNSM 20030 in dorsal (1), cranial (2), lateral (3), caudal (4), and ventral (5) views.
Abbreviations: ca, caudal articular surface; cf, costal fovea; cr, cranial articular surface; lc, lateral concavity; ns, neural spine; poz, postzygapophysis; prz, prezygapophysis; tp, transverse process; vp, ventral process.
Fig 6.
Photographs and interpretative drawings of presacral vertebrae 20 (A) and 21 (B) of UNSM 20030 in dorsal (1), cranial (2), lateral (3), caudal (4), and ventral (5) views.
Abbreviations: ca, caudal articular surface; cf, costal fovea; cr, cranial articular surface; lc, lateral concavity; ns, neural spine; poz, postzygapophysis; prz, prezygapophysis; tp, transverse process; vp, ventral process.
Fig 7.
Photographs and interpretative drawings of presacral vertebrae 22 (A) and 23 (B) of UNSM 20030 in dorsal (1), cranial (2), lateral (3), caudal (4), and ventral (5) views.
Abbreviations: ca, caudal articular surface; cf, costal fovea; cr, cranial articular surface; lc, lateral concavity; ns, neural spine; poz, postzygapophysis; prz, prezygapophysis; tp, transverse process; vp, ventral process.
Fig 8.
Photographs and interpretative drawings of the right ilium, ischium, and pubis of UNSM 20030 in dorsal (A), lateral (B), and ventral (C) views.
Abbreviations: a, acetabulum; at, antitrochanter; f, foramen; g, groove; if, Ilioischiadic fenestra; il, ilium; is, ischium; p, pubis; pt, preacetabular tubercle; s, sinusoidal grooves.
Fig 9.
Photographs of the left acetabular region (A) in lateral (left) and medial (right) views and portions of the left ischium or pubis (B) of UNSM 20030 in lateral view.
Fig 10.
Photographs and interpretative line drawings of the pygostyle of UNSM 20030 in dorsal (A) and ventral (B) views.
Centra are numbered. Abbreviations: dr, dorsal ridge; vr, ventral ridge.
Table 2.
Select measurements of the femur of UNSM 20030, in millimeters.
Fig 11.
Photographs and interpretative line drawings of the right femur of UNSM 20030 in proximal (A), distal (B), cranial (C), caudal (D), lateral (E), and medial (F) views.
Abbreviations: cl, fovea for capital ligament; g, gastrocnemial muscle scar; h, head; is, intercondylar sulcus; lc, lateral condyle; mc, medial condyle; ps, patellar sulcus; tr, trochanter.
Fig 12.
Comparison of the femora of hesperornithiforms in cranial view (left-to-right: Fumicollis hoffmani UNSM 20030; Hesperornis regalis YPM 1200; Baptornis advenus AMNH 5101).
1, arrow indicates the profile of the trochanter, which is rounded in F. hoffmani and B. advenus but more angled in H. regalis. 2, arrow indicates the patellar sulcus, which is pocketed in H. regalis but not in F. hoffmani and B. advenus. Insets: 3, arrow indicates the flattened surface of the lateral condyle; 4, arrow highlights the difference in distal extents of the medial and lateral condyles. In F. hoffmani and B. advenus the lateral condyle extends further distally, while in H. regalis the condyles have a similar extent, with the medial very slightly further than the distal. Insets are shown scaled to be of similar size to F. hoffmani. Abbreviations: h, head; lc, lateral condyle; mc, medial condyle; ps, patellar sulcus; tr, trochanter.
Fig 13.
Comparison of the femora of hesperornithiforms in lateral view (left-to-right: Fumicollis hoffmani UNSM 20030; Hesperornis regalis YPM 1200; Baptornis advenus AMNH 5101).
1, arrow indicates the expanded bulge to the cranial surface of the distal shaft seen in F. hoffmani and H. regalis but not in B. advenus. 2, arrow indicates the narrowing of the distal lateral shaft into a neck proximal to the lateral condyle. The degree of narrowing is most extreme in F. hoffmani, present to a lesser degree in H. regalis, and nearly absent B. advenus. Insets are shown scaled to be of similar size to F. hoffmani. Abbreviations: g, scar for the gastrocnemial muscle; lc, lateral condyle.
Fig 14.
Photograph and interpretative line drawings of the right patella of UNSM 20030 in lateral (A), medial (B), cranial (C), and distal (D) views.
Abbreviations: at, foramen for the ambiens tendon.
Fig 15.
Photographs and interpretative line drawings of the left fibula of UNSM 20030 in proximal (A), lateral (B), cranial (C), medial (D), and caudal (E) views.
Abbreviations: fs, fibular spine; h, head; if, tubercle of the m. iliofibuilaris; pf, popliteal fovea; tc, tibial crest.
Table 3.
Select measurements of the left tibiotarsus of UNSM 20030, in millimeters.
Fig 16.
Photographs and interpretative line drawings of the left tibiotarsus of UNSM 20030 in proximal (A), distal (B), cranial (C), medial (D), caudal (E), and lateral (F) views.
Abbreviations: ce, cnemial expansion; ec, lateral epicondyle; es, extensor sulcus; f, foramen; fc, fibular crest; is, intercondylar sulcus; it, tibiotarsal incision; lc, lateral cotyla; lcc, lateral cnemial crest; ln, lateral condyle; lr, lateral condylar ridge; mc, medial cotyla; mcc, medial cnemial crest; mn, medial condyle; mr, medial condylar ridge.
Fig 17.
Comparison of the tibiotarsi of hesperornithiforms (left-to-right: Fumicollis hoffmani UNSM 20030; Parahesperornis alexi KUVP 2287; Hesperornis regalis YPM 1200; Brodavis varneri SDSM 68430).
A, proximal view, arrow indicates the tibial incisure that wraps up from the lateral side onto the proximal surface, cranial to the lateral cotyla. B, cranial view, shape of the distal lateral margin of the cnemial expansion (arrow). Insets are shown scaled to be of similar size to F. hoffmani. Abbreviations: ce, cnemial expansion; lc, lateral cotyla; mc, medial cotyla.
Fig 18.
Comparison of the tibiotarsi of hesperornithiforms in cranial view (left-to-right: Fumicollis hoffmani UNSM 20030; Parahesperornis alexi KUVP 2287; Hesperornis regalis YPM 1200; Baptornis advenus AMNH 5101).
1, arrow indicates the medial expansion of the distal end, seen to the greatest degree in F. hoffmani and P. alexi. 2, arrows indicate the discrepancy in distal extent of the medial and lateral condyles in F. hoffmani and B. advenus. Insets are shown scaled to be of similar size to F. hoffmani. Abbreviations: es, extensor sulcus; lc, lateral condyle; mc, medial condyle; t, tubercle retinaculi m. fibularis.
Fig 19.
Comparison of the tibiotarsi of hesperornithiforms in lateral view (upper to lower: Baptornis advenus AMNH 5101; Hesperornis regalis YPM 1200; Parahesperornis alexi KUVP 2287; Fumicollis hoffmani UNSM 20030).
Insets are shown scaled to be of similar size to F. hoffmani. Arrow indicates the curvature of the cranial edge of the lateral condyle, which varies across the hesperornithiforms shown. Abbreviations: e, epicondylar depression; lc, lateral condyle.
Table 4.
Select measurements of the right tarsometatarsus of UNSM 20030, in millimeters.
Fig 20.
Photographs and interpretative line drawings of the right tarsometatarsus of UNSM 20030 in dorsal (A, C), plantar (B), lateral (D), medial (E), proximal (F), and distal (G) views.
Abbreviations: df, distal foramen; ie, intercotylar eminence; h, rudimentary hypotarsus; lc, lateral cotyla; mc, medial cotyla; II–IV, trochlea of metatarsals II–IV; Is, scar for metatarsal I; IVr, ridge formed from metatarsal IV.
Fig 21.
Comparison of the tarsometatarsi of hesperornithiforms in dorsal view (left-to-right: Fumicollis hoffmani UNSM 20030; Parahesperornis alexi KUVP 2287; Hesperornis regalis YPM 1200; Baptornis advenus AMNH 5101; Brodavis varneri SDSM 68430).
A, proximal view, shape of the proximal articular surface, with arrows indicating the widths and orientations of the medial and lateral cotylae. B, dorsal view, shape and orientation of the intercotylar eminence (arrow). Insets are shown scaled to be of similar size to F. hoffmani. Abbreviations: ie, intercotylar eminence; lc, lateral cotyla; mc, medial cotyla.
Fig 22.
Comparison of the tarsometatarsi of hesperornithiforms in dorsal view (left-to-right: Fumicollis hoffmani UNSM 20030; Hesperornis regalis YPM 1200; Baptornis advenus AMNH 5101).
Arrow indicates the proximal narrowing of the neck of metatarsal II, which is most pronounced in F. hoffmani. Insets are shown scaled to be of similar size to F. hoffmani. Abbreviations: II, trochlea of metatarsal II; mc, medial cotyla.
Fig 23.
Comparison of the tarsometatarsi of hesperornithiforms in dorsal view (left-to-right: Fumicollis hoffmani UNSM 20030; Hesperornis regalis YPM 1200; Baptornis advenus AMNH 5101; Brodavis varneri SDSM 68430).
1, arrows indicate grooves separating the metatarsals along the shaft of the tarsometatarsus; 2, arrows indicate the shingled arrangement of the metatarsals. Insets are shown scaled to be of similar size to F. hoffmani. Abbreviations: II–IV, trochlea of metatarsals II–IV.
Fig 24.
Comparison of the tarsometatarsi of hesperornithiforms (left-to-right: Fumicollis hoffmani UNSM 20030; Parahesperornis alexi KUVP 2287; Hesperornis regalis YPM 1200; Baptornis advenus AMNH 5101; Brodavis varneri SDSM 68430).
A, dorsal view, relative widths (arrows, 1) and distal extents (2) of metatarsals III and IV. B, distal view, arrangement of the metatarsal trochleae, with arrow (3) indicating spacing between the trochleae of metatarsals III and IV. Insets are shown scaled to be of similar size to F. hoffmani. Abbreviations: II–IV, trochlea of metatarsals II–IV.
Table 5.
Select measurements of the pedal phalanges of UNSM 20030, in millimeters.
Fig 25.
Photographs and interpretative line drawings of the pedal phalanges of Fumicollis hoffmani. Phalanx III:3 (A), III:2 (B), III:1 (C), and II:1 (D) in (top to bottom): lateral, dorsal, and proximal views.
Abbreviations: fc, fovea for the collateral ligament; t, articular trochlea; tf, flexor tubercle.
Fig 26.
Three slabs (A-C) preserving thoracic ribs and uncinate processes of Fumicollis hoffmani.
Abbreviations: r, ribs; up, uncinated process.