Figure 1
Recent discoveries of appendicular skeletal elements of Late Cretaceous titanosaurian sauropods from the Neuquén Basin of southern Argentina. (a) complete and articulated left hind limb of the unnamed La Invernada taxon (MUCPv-1533), (b) complete and articulated distal left hind limb of the unnamed Agua del Padrillo taxon (UNCUYO-LD 313), (c) right humerus of Notocolossus gonzalezparejasi (UNCUYO-LD 301), (d) complete and articulated right pes of Notocolossus gonzalezparejasi (UNCUYO-LD 302). Scale bar equals 10 cm in (d).
Figure 2
Morphological comparison of right scapulae of titanosaurians (a-k) versus those of other sauropods (l-o) in lateral view. South American (Argentinean) taxa denoted with an asterisk. (a) Pitekunsaurus macayai*, redrawn from Filippi and Garrido (2008), (b) Rapetosaurus krausei, redrawn from Curry Rogers (2009), (c) Choconsaurus baileywillisi*, redrawn from Simón et al. (2018), (d) Dreadnoughtus schrani* (left, reversed), redrawn from Lacovara et al. (2014), (e) Muyelensaurus pecheni*, redrawn from Calvo et al. (2007c), (f) Saltasaurus loricatus*, redrawn from Powell (1992), (g) Mendozasaurus neguyelap*, redrawn from González Riga et al. (2018), (h) Patagotitan mayorum*, redrawn from Carballido et al. (2017), (i) Drusilasaura deseadensis* (reversed), redrawn from Navarrete et al. (2011), (j) Opisthocoelicaudia skarzynskii, redrawn from Borsuk-Bialynicka (1977), (k) Elaltitan lilloi*, redrawn from Mannion and Otero (2012), (l) Mamenchisaurus youngi (left, reversed), redrawn from Ouyang and Ye (2002)OUYANG H and YE Y. 2002. The first mamenchisaurian skeleton with complete skull: Mamenchisaurus youngi. Chengdu: Sichuan Scient Tech Press: 1-111., (m) Diplodocus carnegii (left, reversed), redrawn from Hatcher (1901), (n) Giraffatitan brancai (left, reversed), redrawn from Janensch (1961), (o) Camarasaurus supremus (left, reversed), redrawn from Osborn and Mook (1921)OSBORN H and MOOK C. 1921. Camarasaurus, Amphicoelias, and other sauropods of Cope. Mem Am Mus Nat Hist 3: 247-387.. Not to scale.
Figure 3
Morphological comparison of titanosaurian coracoids (a-e) and sternal plates (f-k). South American (Argentinean) taxa denoted with an asterisk. (a) Right coracoid in medial view of Neuquensaurus australis*, MLP-Ly 14, redrawn from Otero (2010), (b) left coracoid in lateral view of Saltasaurus loricatus*, PVL 4017-100, redrawn from Powell (1992), (c) right coracoid in medial view of Quetecsaurus rusconii*, UNCUYO-LD 300.15, redrawn from González Riga and Ortiz David (2014), (d) left coracoid in lateral view of Opisthocoelicaudia skarzynskii, ZPAL MgD-I/48, redrawn from Borsuk-Bialynicka (1977), (e) left coracoid in lateral view of Dreadnoughtus schrani*, MPM-PV 1156, redrawn from Ullmann and Lacovara (2016), (f) right sternal plate in dorsal view of Mendozasaurus neguyelap*, IANIGLA-PV 067, redrawn from González Riga et al. (2018), (g) right sternal plate in dorsal view of Choconsaurus baileywillisi*, MMCh-Pv 44/11, redrawn from Simón et al. (2018), (h) left sternal plate in ventral view of Saltasaurus loricatus*, PVL 4017-102, redrawn from Powell (1992), (i) left sternal plate in ventral view of Narambuenatitan palomoi*, MAU-Pv-N-425, redrawn from Filippi et al. (2011a), (j) left sternal plate in ventral view of Dreadnoughtus schrani*, MPM-PV 1156, redrawn from Ullmann and Lacovara (2016), (k) left sternal plate in ventral view of Petrobrasaurus puestohernandezi*, MAU-Pv-N-449/25, redrawn from Filippi et al. (2011b). Not to scale.
Figure 4
Morphological and size comparison of titanosaurian right humeri in anterior view. South American (Argentinean) taxa marked with an asterisk. (a)
Neuquensaurus australis* (left, reversed), redrawn from Otero (2010), (b)
Rapetosaurus krausei (left, reversed), redrawn from Curry Rogers (2009), (c)
Muyelensaurus pecheni* (left, reversed), redrawn from Calvo et al. (2007c), (d)
Narambuenatitan palomoi* (left, reversed), redrawn from Filippi et al. (2011a), (e)
Mendozasaurus neguyelap*, redrawn from González Riga et al. (2018), (f)
Angolatitan adamastor, redrawn from Mateus et al. (2011)MATEUS O, JACOBS L, SCHULP A, POLCYN M, TAVARES T, BUTA NETO A, MORAIS M and ANTUNES M. 2011. Angolatitan adamastor, a new sauropod dinosaur and the first record from Angola. An Acad Bras Cienc 83: 221-233., (g)
Dreadnoughtus schrani* (left, reversed), redrawn from Lacovara et al. (2014), (h)
Patagotitan mayorum* (left, reversed), redrawn from Carballido et al. (2017), (i)
Paralititan stromeri, redrawn from Smith et al. (2001), (j)
Notocolossus gonzalezparejasi*, redrawn from González Riga et al. (2016). Scale bar equals 20 cm.
Figure 5
(a) Simplified phylogenetic diagram of right metacarpus shape in proximal view in non-titanosaurian Sauropodomorpha and Herrerasaurus, modified from Bonnan (2003)BONNAN M. 2003. The evolution of manus shape in sauropod dinosaurs: implications for functional morphology, forelimb orientation, and phylogeny. J Verteb Paleont 23: 595-613.. The name Brachiosaurus has been replaced by Giraffatitan. Not to scale. (b) Comparison of left metacarpus of selected titanosaurs in proximal view. Argyrosaurus redrawn from Mannion and Otero (2012), Quetecsaurus redrawn from González Riga and Ortiz David (2014), Opisthocoelicaudia redrawn from Borsuk-Bialynicka (1977), La Invernada taxon drawn from personal observation of MUCPv-1533, Epachthosaurus redrawn from Martínez et al. (2004), Rapetosaurus redrawn from Curry Rogers (2009), Choconsaurus redrawn from Simón et al. (2018). Not to scale. (c) Right metacarpus (anterior view) of Epachthosaurus (with phalanx IV-1 in dark gray) and Argyrosaurus, redrawn and modified from Apesteguía (2005), and left metacarpus (anterior view) of Choconsaurus, redrawn from Simón et al. (2018). Roman numerals indicate metacarpal number. Not to scale.
Figure 6
Morphological comparison of pelvic elements of South American (Argentinean) titanosaurs. Ventral view of sacrum and ilia of (a) Neuquensaurus australis, MCS 5/16, redrawn from Salgado et al. (2005) and (b) Overosaurus paradasorum, MAU-Pv-CO-439, redrawn from Coria et al. (2013). Lateral view of left pubis and ischium of (c) Dreadnoughtus schrani, MPM-PV 1156, redrawn from Ullmann and Lacovara (2016), (d) Muyelensaurus pecheni, MRS-Pv 88 (reversed), redrawn from Calvo et al. (2007c), (e) Andesaurus delgadoi, MUCPv-132, redrawn from Mannion and Calvo (2011), (f) Futalognkosaurus dukei, MUCPv-323 (reversed), redrawn from Calvo et al. (2007b). Not to scale.
Figure 7
– Morphological comparison of South American titanosaur femora. (a) Right femur in anterior view of Atacamatitan chilensis, SGO-PV-961g, redrawn from Kellner et al. (2011), (b) left femur in posterior view of Neuquensaurus australis, MLP-CS 1118, redrawn from Otero (2010), (c) right femur in anterior view of ‘Neuquensaurus robustus,’ MCS-9, redrawn from Otero (2010), (d) right femur in posterior view (reversed) of Epachthosaurus sciuttoi, UNPSJB-PV 920, redrawn from Martínez et al. (2004), (e) right femur in posterior view of Saltasaurus loricatus, PVL 4017-79, redrawn from Powell (1992), (f) left femur in posterior view of Petrobrasaurus puestohernandezi, MAU-PV-PH 449/8, redrawn from Filippi et al. (2011b), (g) left femur in posterior view of Mendozasaurus neguyelap, IANIGLA-PV 073/4, redrawn from González Riga et al. (2018), (h) right femur in posterior view (reversed) of Patagotitan mayorum, MPEF-PV 4400/26, redrawn from Carballido et al. (2017), (i) left femur in posterior view of Dreadnoughtus schrani, MPM-PV 1156, redrawn from Ullmann and Lacovara (2016), (j) right femur in posterior view (reversed) of ‘Antarctosaurus’ giganteus, drawn from unpublished photo by L.D.O.D., (k) left femur in posterior view of Bonatitan reigi, MACN-PV RN 821, redrawn from Salgado et al. (2015), (j) left femur in anterior view (reversed) of Traukutitan eocaudata, MUCPv-204, redrawn from Juárez Valieri and Calvo (2011). Not to scale.
Figure 8
Morphological comparison of titanosaurian tibiae (a-e), fibulae (f-l), and tarsals (m-q). South American taxa denoted with an asterisk. (a)-(e), right tibiae in lateral view: (a) Mendozasaurus neguyelap*, IANIGLA-PV 073/2, redrawn from González Riga et al. (2018), (b) Laplatasaurus araukanicus*, MLP-CS 1128, redrawn from Gallina and Otero (2015), (c) Epachthosaurus sciuttoi*, UNPSJB-PV 920, redrawn from Martínez et al. (2004), (d) Dreadnoughtus schrani*, MPM-PV 1156, redrawn from Ullmann and Lacovara (2016), (e) Saltasaurus loricatus*, PVL 4017-84, redrawn from Powell (1992). (f)-(l), left fibulae in lateral view: (f) Laplatasaurus araukanicus* (reversed), MLP-CS 1127, redrawn from Gallina and Otero (2015), (g) Uberabatitan ribeiroi*, CPP-1107-UrHo, redrawn from Salgado and de Souza Carvalho (2008), (h) Epachthosaurus sciuttoi*, UNPSJB-PV 920, redrawn from Martínez et al. (2004), (i) Rapetosaurus krausei (reversed), FMNH PR 2209, redrawn from Curry Rogers (2009), (j) Mendozasaurus neguyelap*, IANIGLA-PV 074/3, redrawn from González Riga (2003), (k) ‘Neuquensaurus robustus’*, MLP-CS 1265, redrawn from Otero (2010), (l)Dreadnoughtus schrani*, MPM-PV 1156, redrawn from Ullmann and Lacovara (2016). (m)-(q), tarsal elements in various views: (m) left astragalus in proximal view of Dreadnoughtus schrani*, MPM-PV 1156, redrawn from Ullmann and Lacovara (2016), (n) right astragalus in anterior view of Notocolossus gonzalezparejasi*, UNCUYO-LD 302, redrawn from González Riga et al. (2016), (o) right astragalus in anterior view of Elaltitan lilloi*, PVL 4628, redrawn from Mannion and Otero (2012), (p) left astragalus in anterior view of Uberabatitan ribeiroi*, CPP-1082-UrHo, redrawn from Salgado and de Souza Carvalho (2008), (q) calcaneum adhered to medial surface of distal fibula of Elaltitan lilloi*, PVL 4628, redrawn from Mannion and Otero (2012). Not to scale.
Figure 9 – The best
The best-preserved pedes of titanosaurian sauropods. South American (Argentinean) taxa marked with an asterisk. (a) Opisthocoelicaudia skarzynskii, ZPAL MgD-I/48, right pes, redrawn from Borsuk-Bialynicka (1977), (b) Epachthosaurus sciuttoi*, UNPSJB-PV 920, right pes, redrawn from Martínez et al. (2004), (c) La Invernada taxon*, MUCPv-1533, left pes, redrawn from González Riga et al. (2008a), (d) Agua del Padrillo taxon*, UNCUYO-LD 313, left pes, redrawn from González Riga et al. (2015), (e) ?Alamosaurus sanjuanensis, NMMNH P-49967, right pes, redrawn from D’Emic et al. (2011), (f) Mendozasaurus neguyelap*, IANIGLA-PV 077/1–10, 078/1–2, 079, right pes, redrawn from González Riga et al. (2018), (G) Notocolossus gonzalezparejasi*, UNCUYO-LD 302, right pes, redrawn from González Riga et al. (2016). Scale bars equal 10 cm.
Figure 10
Four cladistic hypotheses of relationships of titanosaurian taxa. Cladograms have been redrawn and are limited to Titanosauria for ease of comparison. Hypotheses depicted are those of (a) Gallina and Apesteguía (2011), (b) Carballido et al. (2017), (c) Tykoski and Fiorillo (2017), and (d) González Riga et al. (2018). Abbreviations: LO, Lognkosauria, RI, Rinconsauria.
Figure 11
Strict consensus cladogram (limited to Titanosauria) generated from a revised analysis of the data matrix of González Riga et al. (2018) with the addition of three characters (this paper), showing the position and taxonomic content of the newly-recognized stem-based clade Colossosauria. Abbreviations: Lo, Lognkosauria, Ri, Rinconsauria, Sa, Saltasauridae.