Ligabuesaurus leanzai, BONAPARTE, GONZALEZ RIGA & APESTEGUIA, 2006

Bellardini, Flavio, Coria, Rodolfo A, Pino, Diego A, Windholz, Guillermo J, Baiano, Mattia A & Martinelli, Augustin G, 2022, Osteology and phylogenetic relationships of Ligabuesaurus leanzai (Dinosauria: Sauropoda) from the Early Cretaceous of the Neuquén Basin, Patagonia, Argentina, Zoological Journal of the Linnean Society 196 (4), pp. 1333-1393 : 1337-1378

LIGABUESAURUS LEANZAI BONAPARTE, GONZÁLEZ RIGA & APESTEGUÍA, 2006

Type species and etymology

The name of the type species was erected in honour of geologist Dr Héctor Leanza, who reported about the presence of fossils at Cerro de los Leones, Picún Leufú, Neuquén Province, Argentina.

Holotype

MCF-PVPH-233 ( Fig. 4A ): a single, large-sized, incomplete and disarticulated sauropod specimen represented by ten maxillary teeth (MCF-PVPH-233/ 01), a posterior cervical vertebra (MCF-PVPH-233/02), an anterior dorsal vertebra (MCF-PVPH- 233 / 03), two articulated midposterior dorsal vertebrae (MCF-PVPH-233/04 and MCF-PVPH- 233 / 05), two articulated posterior dorsal vertebrae (MCF-PVPH-233/06 and MCF-PVPH-233/07), both scapulae (MCF-PVPH-233/08 and MCF-PVPH-233/09), a left humerus (MCF-PVPH-233/10), a proximal and distal epiphysis of the right humerus (MCF-PVPH-233/11 and MCF-PVPH-233/12), a right metacarpal II (MCF-PVPH- 233/13), a right metacarpal III (MCF-PVPH- 233/ 14), a distal epiphysis of the left metacarpal II (MCF-PVPH-233/15), a distal epiphysis of the left metacarpal IV (MCF-PVPH-233/16), a right femur (MCF-PVPH-233/17), a right tibia (MCF-PVPH-233/18), a right fibula (MCF-PVPH-233/19), a right astragalus (MCF-PVPH-233/20) and a nearly complete and articulated right pes, with five metatarsals and three phalanges (MCF-PVPH-233/21–MCF-PVPH-233/28).

Referred specimens

MCF-PVPH-261 ( Fig. 4A ): several postcranial elements from the type quarry no. 4 of Ligabuesaurus , consisting of a mid-cervical vertebra (MCF-PVPH-261/16), two posterior cervical vertebrae (MCF-PVPH-261/01 and MCF-PVPH-261/02), an anterior caudal vertebra (MCF-PVPH-261/15), an incomplete dorsal rib (MCF-PVPH-261/17), both coracoids (MCF-PVPH-261/05 and MCF-PVPH-261/06), a distal half of left radius(?) (MCF-PVPH-261/07), a partial left ilium (MCF-PVPH-261/08), both pubes (MCF-PVPH-261/09–MCF-PVPH-261/11), a left femur (MCF-PVPH-261/12), a proximal epiphysis of the left tibia (MCF-PVPH-261/13) and a proximal epiphysis of the left fibula (MCF-PVPH-261/14).

MCF-PVPH-228 and MCF-PVPH-908 ( Fig. 4B ), a single, large-sized and incomplete sauropod specimen from quarry no. 3, represented by the following associated bones: two articulated posterior cervical vertebrae (MCF-PVPH- 228 / 01 and MCF-PVPH-261/02), an anterior dorsal vertebra (MCF-PVPH-908), two articulated mid-posterior dorsal vertebrae (MCF-PVPH-228/03 and MCF-PVPH-228/04), six incomplete dorsal ribs (MCF-PVPH-228/05–MCF-PVPH-261/10) and a right scapula (MCF-PVPH-228/11).

MCF-PVPH-744 ( Fig. 4B ), one isolated, almost complete tooth.

See the Supporting Information ( Table S1 and Section 1.1.2 ‘Comments on referred specimens of Ligabuesaurus ’) for considerations about the composition of the type material of Ligabuesaurus .

Locality and horizon

The fossil remains of Ligabuesaurus come from the Cerro de los Leones locality, a hill located ~ 10 km to the southwest of Picún Leufú city, southern Neuquén Province, Patagonia, Argentina ( Fig. 1A, B ). The fluvial deposits outcropping in this area were referred to the lower section of the Cullin Grande Member ( Martinelli et al., 2007), the upper member of the Lohan Cura Formation (Bajada del Agrio Group, Lower Cretaceous, Albian). The type quarry (no. 4) was opened in the fossiliferous level no. 2 (sensu Martinelli et al., 2007) in the southern flank of the Cerro de los Leones ( Fig. 1C ) and 40 m to the east of quarry no. 3, where part of the referred specimen was found (Supporting Information, Table S1). The sauropod remains were found in laminate mudstones with interbedded fine- to very fine-grained sandstones. These fluvial deposits were dated as Albian and are considered to have been formed in a distal floodplain in semi-arid climatic conditions ( Martinelli et al., 2007).

Comments on original diagnosis

In the original description of Ligabuesaurus, Bonaparte et al. (2006) identified four autapomorphies. The first three are listed below with the numbers (1), (2) and (3). The fourth autapomorphy, listed by Bonaparte et al. (2006) as (4) rudimentary prespinal lamina (prsl) on the posterior cervical and anterior dorsal vertebrae, is not used here for the following reasons: in the posterior cervical vertebra MCF-PVPH-233/02 the prsl is not present ( Fig. 5L ), whereas in the anterior dorsal vertebra MCF-PVPH-233/03 there is a reduced lamina on the dorsalmost portion of the anterior face of the neural spine ( Fig. 5M ). However, in the anterior dorsal vertebra MCF-PVPH-908 the prsl is not rudimentary but represented by a narrow and prominent lamina, well developed from the base to the apex of the neural spine ( Fig. 5N ). Therefore, we consider that the rudimentary prsl on the posterior cervical and anterior dorsal vertebrae is not a pertinent autapomorphy for Ligabuesaurus and exclude it from the diagnosis.

Revised diagnosis

Ligabuesaurus leanzai is characterized by the following autapomorphies: (1) laminar and anteroposteriorly compressed neural spines on posterior cervical and anterior dorsal vertebrae that are rhomboid in shape and wider than the vertebral centra; (2) spinoprezygapophyseal laminae in posterior cervical vertebrae forked to form two pairs of laminae: the medial pair unites them towards the top of the neural spine, and the lateral pair form the lateral border of the neural spine; (3) posterior cervical and anterior dorsal vertebrae with low neural arch pedicels, less than onethird of the height of the anterior articular surface; (4) humeral head expanded posteriorly ( D’Emic, 2012); (5) quadrangular ventral half of the coracoid in lateral view ( Fig. 5A ); (6) fossae on proximoventral faces of metatarsals II and III ( D’Emic, 2012); and (7) deep pit on ventrodistal face of pedal phalanx II-1 (modified from D’Emic, 2012). With regard to (4), (6) and (7), in the extended contribution on the early evolution of Titanosauriformes, D’Emic (2012; appendix 4) also provided a diagnosis for Ligabuesaurus , identifying five autapomorphies, some of which are not included in the diagnosis to represent morphological features with a wide distribution within Sauropoda. In this sense, the distal scapular blade with rounded dorsal expansion (autapomorphy 1; D’Emic, 2012) is a condition that Ligabuesaurus shares with several Titanosauriformes (e.g. Brachiosaurus Riggs, 1903 , Brontomerus Taylor, Wedel & Cifelli, 2011 , Euhelopus Romer, 1956 , Giraffatitan Paul, 1988 , Rukwatitan Gorscak et al., 2014 ), hence it is excluded from the diagnosis. Likewise, the gracile humerus of Ligabuesaurus (autapomorphy 3; D’Emic, 2012) is a plesiomorphic condition that is also present in several sauropods, such as Alamosaurus Gilmore, 1922 , Chubutisaurus Del Corro, 1975 , Europasaurus Mateus et al. in Sander et al., 2006, Giraffatitan , Patagosaurus Bonaparte, 1979 , Rinconsaurus Calvo & González Riga, 2003 and Wintonotitan Hocknull et al., 2009 . In contrast, we agree with D’Emic that the deep pit on the ventrodistal face of the pedal phalanx represents an autapomorphy of Ligabuesaurus (autapomorphy 5; D’Emic, 2012), but we have reconsidered the pedal element (MCF-PVPH-233/28) as a phalanx II-1 and not a I-1 (contra D’Emic, 2012). However, also in the phalanx I-1 (MCF-PVPH-233/26) there is a ventrodistal vascular foramen, but it is small and poorly preserved, hence it is not included in the present diagnosis.

Figures

Figure 1. Location map. A, satellite map of northern Patagonia (Argentina), showing the approximate limits of Neuquén Basin (white dashed line). B, the Cerro de los Leones locality is ~10 km to the south-west of Picún Leufú city, to the south of the Neuquén Province (white crossed pickaxes). C, satellite map of the main quarries opened on the southern flank of the Cerro de los Leones, where outcropping of the fluvial sediments of the Lohan Cura Formation (Albian) occurs.

Figure 2. Lithological profile. A schematic log of the the lower section of the Cullin Grande Member (Bajada del Agrio Group, Lohan Cura Formation, Lower Cretaceous, Albian) that outcrops at the Cerro de los Leones locality (modified from Martinelli et al., 2007). Abbreviations: CS, crevasse channel; FF, floodplain fines; FL, fossiliferous level; LA, lateral accretion; LS, laminated sand sheets; LV, levee; SB, sandy bedforms. Architectural element codes follow Miall (1996).

Figure 3. Original picture of quarry no. 4 during the fieldwork of 2004 (A) and a quarry map with tentative arrangement of the holotype (in red) and referred material (in blue) of Ligabuesaurus leanzai (B). Abbreviations: ant, anterior; s/n, without collection number; v, vertebra.

Figure 4. The somphospondylan sauropod Ligabuesaurus leanzai from Cerro de los Leones (Neuquén Province, Patagonia, Argentina). A, skeletal reconstruction based on the holotype (MCF-PVPH-233) and referred material (MCF-PVPH-261) from quarry no. 4, plus the newly referred specimens from quarry no. 3 (MCF-PVPH-228, MCF-PVPH-744 and MCF- PVPH-908). B, life restoration of Ligabuesaurus leanzai as a non-titanosaurian somphospondylan by J. L. Blanco.

Figure 5. New autapomorphic feature and revised diagnosis of Ligabuesaurus leanzai. A, Photograph and line drawings of the left coracoid MCF-PVPH-261/05 in lateral view. The quadrangular ventral half of the coracoid in lateral view is here proposedasauniquelyderivedfeatureofLigabuesaurusleanzainotpresentinanyothersauropods.B–K,comparativeoutlines of sauropod coracoids: B, Neuquensaurus MLP-Ly-14; C, Saltasaurus PVL-4017-100; D, Quetecsaurus UNCUYO-LD-300.15; E, Opisthocoelicaudia ZPAL-MgD-I/48; F, Dreadnoughtus MPM-PV-1156; G, Tapuiasaurus MZSP-PV-807; H, Uberabatitan CPP-1109-UrHo; I, Suuwassea ANS 21122; J, Patagotitan MPEF-PV-3400/24; K, Zby ML 368. L–N, line drawings of the posterior cervical vertebra MCF-PVPH-233/02 (L) and anterior dorsal vertebrae MCF-PVPH-233/03 (M) and MCF- PVPH-908 (N), showing the development of the prespinal lamina on the anterior surface of the neural spine (green triangle). B–K modified from González Riga et al. (2019). Not to scale. Scale bar: 10 cm in L–N.

Figure 6. Photographs and line drawings of the teeth of Ligabuesaurus leanzai. A, ten maxillary teeth and fragments of unerupted teeth in sedimentary matrix MCF-PVPH-233/01 in lingual view. B–F, isolated maxillary tooth MCF-PVPH-744 in lingual (B), apical (C), labial (D), mesial (E) and distal (F) views. Abbreviations: awf, apical wear facet; cc, cingular cusp; de, dentine surface; e, enamel surface; mg, mesial groove; mwf, mesial wear facet; rt, replacement tooth fragment; tc, tooth crown; tr, tooth root; t-1/10, tooth no. 1 and no. 10; we, wrinkled enamel surface. Scale bar: 3 cm.

Figure 7. A, detail ofthe microwear pattern on the apicalwear facet of the maxillary tooth MCF-PVPH-744 of Ligabuesaurus leanzai. Most of the pits and coarse grooves are evident with a binocular microscope (α) on the dentine exposed surface, whereas the scanning electron photomicrographs (β, γ, δ and ε) show abundant fine scars in both the enamel and dentine surfaces. Abbreviations: g, coarse groove; p, pit; s, fine scar.

Figure 8. Photographs and line drawings of the middle cervical vertebra MCF-PVPH-261/16 of Ligabuesaurus leanzai in dorsal (A), ventral (B) and left lateral (C) views. Abbreviations: acdl, anterior centrodiapophyseal lamina; apo, accessory pneumatic opening; cpol, centropostzygapophyseal lamina; cprl, centroprezygapophyseal lamina; di, diapophysis; nc, neural canal; pa, parapophysis; pcdl, posterior centrodiapophyseal lamina; pl, pleurocoel; prdl, prezygodiapophyseal lamina; prz, prezygapophysis; pvr, posteroventral ridges; spdl, spinodiapophyseal lamina; sprl, spinoprezygapophyseal lamina. Scale bar: 10 cm.

Figure 9. Photographs and line drawings of the posterior cervical vertebra MCF-PVPH-261/01 of Ligabuesaurus leanzai in anterior (A), posterior (B) and left lateral (C) views. Abbreviations: aas, anterior articular surface; apf, anterior pneumatic fossa; cprl, centroprezygapophyseal lamina; di, diapophysis; pa, parapophysis; pas, posterior articular surface; ppf, posterior pneumatic fossa; prz, prezygapophysis; r?, fragment of rib. Scale bar: 10 cm.

Figure 10. Photographs and line drawings of the posterior cervical vertebra MCF-PVPH-261/02 of Ligabuesaurus leanzai in anterior (A), posterior (B) and right lateral (C) views. Abbreviations: apf, anterior pneumatic fossa; cprl, centroprezygapophyseal lamina; di, diapophysis; nc, neural canal; pa, parapophysis; ppf, posterior pneumatic fossa; prz, prezygapophysis. Scale bar: 10 cm.

Figure 11. Photographs and line drawings of the posterior cervical vertebra MCF-PVPH-228/01 and MCF-PVPH-228/02 of Ligabuesaurus leanzai in anterior (A) view. Abbreviations: aas, anterior articular surface; cpol, centropostzygapophyseal lamina; di, diapophysis; poz, postzygapophysis; prdl, prezygodiapohyseal lamina; prz, prezygapophysis; sprl, spinoprezygapophyseal lamina; tprl, intraprezygapophyseal lamina. Scale bar: 10 cm.

Figure 12. Photographs and line drawings of the posterior cervical vertebra MCF-PVPH-233/02 of Ligabuesaurus leanzai in anterior (A), posterior (B) and right lateral (C) views. Abbreviations: acdl, anterior centrodiapophyseal lamina; cpol, centropostzygapophyseal lamina; cprl, centroprezygapophyseal lamina; di, diapophysis; lat. sprl, lateral spinoprezygapophyseal lamina; med. sprl, medial spinoprezygapophyseal lamina; nc, neural canal; ns, neural spine; pa, parapophysis; pcdl, posterior centrodiapophyseal lamina; pl, pleurocoel; podl, postzygodiapophyseal lamina; posl, postspinal lamina; poz, postzygapophysis; prdl, prezygodiapophyseal lamina; prz, prezygapophysis; r?, fragment of rib; spdl, spinodiapophyseal lamina; spol, spinopostzygapophyseal lamina; sprl, spinoprezygapophyseal lamina. Scale bar: 10 cm.

Figure 13. Photographs and line drawings of the anterior dorsal vertebra MCF-PVPH-233/03 of Ligabuesaurus leanzai in anterior (A), posterior (B) and left lateral (C) views. Abbreviations: acdl, anterior centrodiapophyseal lamina; cpol, centropostzygapophyseal lamina; cprl, centroprezygapophyseal lamina; di, diapophysis; lat. sprl, lateral spinoprezygapophyseal lamina; med. sprl, medial spinoprezygapophyseal lamina; nc, neural canal; pa, parapophysis; pcdl, posterior centrodiapophyseal lamina; pl, pleurocoel; poz, postzygapophysis; prsl, prespinal lamina; prz, prezygapophysis; spdl, spinodiapophyseal lamina; spol, spinopostzygapophyseal lamina; tprl, intraprezygapophyseal lamina. Scale bar: 10 cm.

Figure 14. Photograph and line drawing of the anterior dorsal vertebra MCF-PVPH-908 of Ligabuesaurus leanzai in anterior view.Abbreviations:acdl, anterior centrodiapophyseal lamina; cprl, centroprezygapophyseallamina; di, diapophysis; lat. sprl, lateral spinoprezygapophyseal lamina; med. sprl, medial spinoprezygapophyseal lamina; pa, parapophysis; prsl, prespinal lamina; prz, prezygapophysis; spdl, spinodiapophyseal lamina; sprf, spinoprezygapophyseal fossa; tprl, intraprezygapophyseal lamina. Scale bar: 10 cm.

Figure 15. Photograph and line drawings of the mid-posterior dorsal vertebrae MCF-PVPH-233/04 and MCF- PVPH-233/05 of Ligabuesaurus leanzai in left lateral view. Abbreviations: acdl, anterior centrodiapophyseal lamina; acpl, anterior centroparapophyseal lamina; pa, parapophysis; pcdl, posterior centrodiapophyseal lamina; pcpl, posterior centroparapophyseal lamina; pl, pleurocoel; poz, postzygapophysis; ppdl, parapophysisdiapophyseal lamina; prz, prezygapophysis. Scale bar: 10 cm.

Figure 16. Photographs and line drawings of the mid-posterior dorsal vertebrae MCF-PVPH-228/03 and MCF- PVPH-228/04 of Ligabuesaurus leanzai in left lateral (A), anterior (B) and posterior (C) views. Abbreviations: acdl, anterior centrodiapophyseal lamina; acpl, anterior centroparapophyseal lamina; cpol, centropostzygapophyseal lamina; hypa, hypantrum; pcdl, posterior centrodiapophyseal lamina; pcpl, posterior centroparapophyseal lamina; pl, pleurocoel; poz, postzygapophysis; ppdl, parapophysisdiapophyseal lamina; prz, prezygapophysis; spdl, spinodiapophyseal lamina; spol, spinopostzygapophyseal lamina; sprl, spinoprezygapophyseal lamina. Scale bar: 10 cm.

Figure 17. Photographs and line drawings of the posterior dorsal vertebrae MCF-PVPH-233/06 and MCF-PVPH-233/07 of Ligabuesaurus leanzai in anterior (A) and posterior (B) views. Abbreviations: acc. spdl, accessory spinodiapophyseal lamina; cpol, centropostzygapophyseal lamina; di, diapophysis; hypo, hyposphene; pcdl, posterior centrodiapophyseal lamina; poz, postzygapophysis; prsl, prespinal lamina; prz, prezygapophysis; spdl, spinodiapophyseal lamina; sprl, spinoprezygapophyseal lamina. Scale bar: 10 cm.

Figure 18. Photographs and line drawings of the caudal vertebra and dorsal rib of Ligabuesaurus leanzai. A–E, anterior caudal vertebra MCF-PVPH-261/15 in anterior (A), posterior (B), left lateral (C), dorsal (D) and ventral (E) views. F, G, dorsal rib MCF-PVPH-228/10 in medial view (F), with a detail of the internal pneumatic structure on the process of the capitulum (G). Abbreviations: aas, anterior articular surface; cap, capitulum; nc, neural canal; pas, posterior articular surface; rs, rib shaft; tp, transverse process; tub, tuberculum; vf, vascular foramen. Scale bars: 10 cm.

Figure 19. Pectoral girdle elements of Ligabuesaurus leanzai. A, Right scapula MCF-PVPH-228/11 in lateral view. B, left scapula MCF-PVPH-233/08 in lateral view. C–E, left coracoid MCF-PVPH-261/05 in lateral (C), distal (D) and medial views (E). F–H, right coracoid MCF-PVPH-261/06 in medial (F), distal (G) and lateral (H) views.Abbreviations:af, anterior fossa; ar, acromial ridge; br, attachment surface for muscle biceps brachii; cbb, attachment surface for muscle coracobrachialis brevis; f, coracoid foramen; gl, glenoid; ign, infraglenoid notch; lev sc, attachment surface for levator scapulae; mvp, medioventral process; pf, posterior fossa; scs, scapulocoracoid articular surface; sr, scapular ridge. Scale bars: 10 cm.

Figure 20. Photographs and line drawings of the forelimb elements of Ligabuesaurus leanzai. A–D, left humerus MCF- PVPH-233/10 in anterior (A), proximal (B), distal (C) and posterior (D) views. E, F, distal half of the right humerus MCF- PVPH-233/12 in anterior (E) and distal (F) views. G–I, distal half of the left radius MCF-PVPH-261/07 in posterior (G), distal (H) and lateral (I) views. Abbreviations: ac, accessory condyles; anf, anconeal fossa; das, distal articular surface; dpc, deltopectoral crest; dpf, deltopectoral fossa; hh, humeral head; ltf, lateral triceps fossa; mtf, medial triceps fossa; rc, radial condyle; uas, ulnar articular surface; uc, ulnar condyle. Scale bars: 10 cm.

Figure 21. Photographs and line drawings of the manus of Ligabuesaurus leanzai. A–D, right metacarpal II MCF- PVPH-233/13 in medial (A), proximal (B), distal (C) and lateral (D) views. E, distal epiphysis of the left metacarpal II MCF-PVPH-233/15 in distal view. F–I, right metacarpal III MCF-PVPH-233/14 in lateral (F), proximal (G), distal (H) and medial (I) views. J, distal epiphysis of the left metacarpal IV MCF-PVPH-233/16 in distal view. Abbreviations: am, anterior margin; lm, lateral margin; McI, articular surface for metacarpal I; McII, articular surface for metacarpal II; McIII, articular surface for metacarpal III; McIV, articular surface for metacarpal IV; pm, posterior margin; vlr, ventrolateral ridge. Scale bars: 10 cm.

Figure 23. Photographs and line drawings of the femora of Ligabuesaurus leanzai. A–C, right femur MCF-PVPH-233/17 in anterior (A), posterior (B) and distal (C) views. D–G, left femur MCF-PVPH-261/12 in anterior (D), distal (E), posterior (F) and medial (G) views. Abbreviations: ec, epicondyle; fc, fibular condyle; fh, femoral head; ft, fourth trochanter; ftr, femoral trochlea; gt, great trochanter; icf, intracondylar fossa; icg, intracondylar groove; lb, lateral bulge; lic, linea intermuscularis cranialis; tc, tibial condyle. Scale bars: 10 cm.

Figure 24. Photographs and line drawings of the hindlimb elements of Ligabuesaurus leanzai. A–E, right tibia MCF- PVPH-233/18 in anterior (A), lateral (B), posterior (C), proximal (D) and distal (E) views. F–I, proximal epiphysis of the left tibia MCF-PVPH-261/13 in proximal (F), posterior (G), lateral (H) and medial (I) views.J–M, right fibula MCF-PVPH-233/19 in medial (J), anterior (K), proximal (L) and distal (M) views. N, O, proximal epiphysis of the left fibula MCF-PVPH-261/14 in proximal (N) and medial (O) views.Abbreviations:amc, anteromedial crest; amf, anteromedial fossa; ap, anterior process; asap, articular surface for the ascending process; asp, astragal process; at, anterior trochanter; cc, cnemial crest; cf,cnemial fossa; lt, lateral trochanter; mi, insertion surface for muscle iliofibularis; pp, posterior process; tas, tibial articular surface. Scale bars: 10 cm.

Figure 25. Photographs and line drawings of the right astragalus MCF-PVPH-233/20 of Ligabuesaurus leanzai in anterior (A), dorsal (B), lateral (C), posterior (D), ventral (E) and medial (F) views. Abbreviations: apr, ascending process of astragalus; cas, calcaneal articular surface; cpf, crest of posterior fossa; das, distal articular surface; fas, fibular articular surface; ilg, intertarsal ligament groove; pf, posterior fossa; tas, tibial articular surface. Scale bar: 10 cm.

Figure 26. Photographs and line drawings of the pedal elements of Ligabuesaurus leanzai. A–C, right metatarsal I MCF- PVPH-233/21 in posterior (A), proximal (B) and distal (C) views. D–F, right metatarsal II MCF-PVPH-233/22 in posterior (D), proximal (E) and distal (F) views. G–I, right metatarsal III MCF-PVPH-233/23 in posterior (G), proximal (H) and distal (I) views. J, K, right metatarsal IV MCF-PVPH-233/24 in posterior (J) and proximal (K) views. L, M, right metatarsal V MCF- PVPH-233/25 in posterior (L) and proximal (M) views. N, right proximal phalanx I-1 MCF-PVPH-233/26 in posterior view. O, right ungueal phalanx MCF-PVPH-233/27 in medial view. P, right proximal phalanx II-1 MCF-PVPH-233/28 in posterior view. Abbreviations: I, articular surface for metatarsal I; II, articular surface for metatarsal II; III, articular surface for metatarsal III; icg, intercondylar groove; IV, articular surface for metatarsal IV; lc, lateral condyle; mdp, mediodistal process; mh, medial hollow; pas, proximal articular surface; V, articular surface for metatarsal V; vf, vascular foramen. Scale bars: 10 cm.

Figure22. Photographsand linedrawingsofpelvicgirdleelementsofLigabuesaurus leanzai.A,leftilium MCF-PVPH-261/08 in lateral view. B–D, proximal half of the right pubis MCF-PVPH-261/10 in lateral (B), proximal (C) and medial (D) views. E, F, proximal half of the left pubis MCF-PVPH-261/09 in lateral (E) and proximal (F) views. G, reconstruction of right pubis in lateral view, assembling the proximal and distal halves MCF-PVPH-261/10 and MCF-PVPH-261/11. H–J, distal half of the right pubis MCF-PVPH-261/11 in anterior (H), lateral (I) and distal (J) views. Abbreviations: acet, acetabulum; am, anterior margin; ias, ischiatic articular surface; ip, ischiatic peduncle; lm, lateral margin; mm, medial margin; of, obturator foramen; poap, postacetabular process; pp, pubic peduncle; prap, preacetabular process. Scale bars: 10 cm.