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Appendicular skeleton and dermal armour of the Late Cretaceous titanosaur Lirainosaurus astibiae (Dinosauria: Sauropoda) from Spain

Verónica Díez Díaz, Xabier Pereda Suberbiola, and José Luis Sanz

Plain Language Abstract

The appendicular skeleton and osteoderms of the Spanish titanosaur (Dinosauria: Sauropoda) Lirainosaurus astibiae

Titanosaurs were the most succesful and diverse group of sauropod dinosaurs from the Late Cretaceous. They inhabited every landmass, even Antarctica, and were the only clade within Sauropoda that reached the end of the Mesozoic.

Five titanosaurian species are well-known from the Late Cretaceous of Europe: Magyarosaurus and Paludititan from Romania, Ampelosaurus and Atsinganosaurus from France, and Lirainosaurus from Spain. Nowadays, Lirainosaurus is one of the best-known titanosaurs from Europe, thanks to the detailed description of its cranial (basicrania and teeth) and postcranial (axial and appendicular remains, and osteoderms) remains.

This paper focuses on the description of the appendicular skeleton and dermal armour of Lirainosaurus, and the comparison with the other European titanosaurs confirms that it clearly differs from them. In addition, a body size up to 6 meters and a body mass of at least 2-4 tonnes for the largest individuals of Lirainosaurus is suggested, being one of the most slender titanosaurs found to date.

Resumen en Español

Esqueleto apendicular y armadura dérmica del titanosaurio Lirainosaurus astibiae (Dinosauria: Sauropoda) del Cretácico superior de España

Lirainosaurus astibiae es el mejor conocido de los saurópodos titanosaurios de la Península Ibérica. Fue descrito inicialmente por Sanz y colaboradores en 1999 a partir de varios restos craneales y postcraneales del Cretácico superior de Laño (norte de España). Recientemente nuevos restos procedentes de esta y otras localidades ibéricas han sido atribuidos a la especie. Este artículo se centra en la descripción del esqueleto apendicular y de la armadura dérmica de Lirainosaurus. La comparación con otros titanosaurios europeos confirma que Lirainosaurus astibiae se diferencia claramente de ellos y resalta dos características apendiculares diagnósticas: la presencia de una prominencia dorsal junto con una cresta ventral en la cara medial de la lámina escapular y la combinación de un proceso anterolateral y una cresta anteroventral en la placa esternal. La aplicación de las ecuaciones para la estimación de la masa corporal y el tamaño en saurópodos sugiere una longitud de hasta 6 metros y un peso de entre 2 y 4 toneladas para los individuos más grandes de Lirainosaurus astibiae, lo que lo convierte en uno de los titanosaurios más gráciles hallados hasta la fecha. El estudio del esqueleto postcraneal no axial apoya la hipótesis de que Lirainosaurus astibiae es un litostrotio derivado cercano a los Saltasauridae.

Palabras clave: Lirainosaurus; Titanosauria; esqueleto apendicular; armadura dérmica; España; Cretácico superior

Traducción: Miguel Company

Résumé en Français

Squelette appendiculaire et armure dermique du titanosaur du Crétacé supérieur Lirainosaurus astibiae (Dinosauria: Sauropoda) de l'Espagne

Lirainosaurus astibiae est la plus connue des espèces de sauropodes titanosaurien de la péninsule ibérique. Elle a été décrite par Sanz et ces collaborateurs en 1999 à base de plusieurs restes crâniens et postcrâniens du Crétacé supérieur de Lano (nord de l'Espagne) ; de nouveaux restes de cet endroit et de d'autres sites fossiles ibériques ont récemment été rapportés à cette espèce. Ce papier se concentre sur la description du squelette appendiculaire et de l'armure dermique de Lirainosaurus. La comparaison avec d'autres titanosaures européens confirme que Lirainosaurus astibiae diffère clairement des autres espèces, et met à jours deux caractéristiques appendiculaires diagnostiques: la présence d'une proéminence dorsale avec une crête ventrale sur la surface interne de la lame scapulaire, et la combinaison d'une excroissance antérolatérale et une crête antéro-ventrale sur la plaque sternale. Les équations de prédiction de la masse corporelle et la taille chez les sauropodes suggèrent une taille de corps jusqu'à 6 mètres et une masse corporelle d'au moins 2-4 tonnes pour les plus grands individus de Lirainosaurus astibiae, il est l'un des plus sveltes titanosaures trouvés à ce jour. L'étude du squelette postcrânien non-axiale soutient l'hypothèse que Lirainosaurus astibiae est un lithostrotian près de la famille Saltasauridae.

Mots-clés: Lirainosaurus; Titanosauria; squelette appendiculaire; armure dermique; Espagne; Crétacé supérieur

Translator: Olivier Maridet

Deutsche Zusammenfassung

Appendikular-Skelett und Hautpanzer des spätkretazischen Titanosauriers Lirainosaurus astibiae (Dinosauria: Sauropoda) aus Spanien

Lirainosaurus astibiae ist die am besten bekannte titanosauride Sauropodenart der Iberischen Halbinsel. Er wurde 1999 von Sanz und Mitarbeitern auf der Basis von einigen cranialen und postcranialen Überresten aus der späten Kreide von Laño (Nordspanien) beschrieben; neue Funde von dieser und anderen iberischen Fossil-Fundstätten wurden kürzlich dieser Art zugeschrieben. Diese Arbeit konzentriert sich auf die Beschreibung des Appendikular-Skeletts und den Hautpanzer von Lirainosaurus. Vergleiche mit anderen europäischen Titanosauriern bestätigen, dass Lirainosaurus sich deutlich von diesen unterscheidet und streichen zwei diagnostische Merkmale im Appendikular-Skelett heraus: das Vorhandensein einer dorsalen Wölbung zusammen mit einem ventralen Kamm auf der medialen Oberfläche des Schulterblatts und die Kombination von einem anterolateralen Vorsprung mit einem anteroventralen Kamm auf dem Sternum. Kalkulationen zu Maßen bei Sauropoden weisen auf eine Größe bis zu sechs Meter und ein Gewicht von bis zu zwei bis vier Tonnen für die größten Individuen von Lirainosaurus astibiae hin. Damit gehört das Skelett zu einem der schmaleren bis jetzt gefundenen Titanosauriden. Untersuchungen des nicht-axialen Postkranialskeletts unterstützten die Annahme, dass Lirainosaurus astibiae ein abgeleiteter Lithostrotide ist, nahe verwandt mit den Saltasauridae.

Schlüsselwörter: Lirainosaurus; Titanosauria; Appendikular-Skelett; Hautpanzer; Spanien; Obere Kreide

Translator: Eva Gebauer

Arabic

350 arab

Translator: Ashraf M.T. Elewa

 

 

TABLE 1. Appendicular skeleton and dermal armour, MCNA collection.

 

Scapulae

MCNA 7459, 13855, 14461, 14462

Coracoids

MCNA 1846, 3158, 7460

Sternal plate

MCNA 7461

Humeri

MCNA 7462-7465, 14463

Ulna

MCNA 3157

Ilia

MCNA 7456, 8609, 13861, 14464

Pubis

MCNA 7467

Femora

MCNA 1817, 3160, 7468, 14465-14468

Tibiae

MCNA 2203, 7471, 13860, 14469, 14470

Fibulae

MCNA 7472, 9410, 14471

III Metatarsal

MCNA 14474

Osteoderms

MCNA 14473, 14474

TABLE 2. Measurements of the best-preserved specimens (in cm) of the pectoral girdle of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous of Laño (northern Spain). Abbreviations: *: eroded edges; Max. APL: maximum anteroposterior length; Max. DVH: maximum dorsoventral height; Max./Min. DVH sb: maximum/minimum dorsoventral height of the scapular blade; Max. L glenoid: maximum length of the glenoid surface.

 

SCAPULAE

 

Total Length

Max. DVH sb

Min. DVH sb

 

MCNA 7459

55,19*

12.9

8.7

 

MCNA 13855

-

12

10.1

 

MCNA 14461

72.2

13.9

11.9

 

MCNA 14462

-

9.2

-

 

CORACOIDS

 

Max. DVH

Max. APL

Foramen Width

Max. L glenoid

MCNA 1846

25,9*

27,4*

1,6*

-

MCNA 3158

24

23.3

2,2*

11.4

MCNA 7460

17,5*

18,6*

1.7

10.64

TABLE 3. Measurements of the best-preserved specimens (in cm) of the forelimb of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous of Laño (northern Spain). The measures with a ? symbol are approximate as iron oxides cover the surface of the bones. Abbreviations: **: eroded proximal and/or distal ends; Dist. Prx-D dpc: distance from proximal end to distal end of deltopectoral crest; Max. Φ: maximum diameter in the narrowest part of the diaphysis; MDW: maximum width of the distal end; Min. Φ: minimum diameter in the narrowest part of the diaphysis; MPW: maximum width of the proximal end; Per: perimeter in the narrowest part of the diaphysis; RI = average of the greatest widths of the proximal end, mid-shaft and distal end of the element/length of the element (Wilson and Upchurch, 2003).

 

HUMERI

 

Length

Max. Φ

Min. Φ

Per.

MPW

MDW

Dist. Prx-D dpc

RI

ECC

MCNA 7462

-

8,3 cm

4 cm

22,9 cm

-

-

16.5

-

2.075

MCNA 7463

53,1 cm

8,5 cm

? 4,2 cm

22,1 cm

20,9 cm

16,6 cm

18.5

-

2.023

MCNA 7464

66 cm**

9,5 cm

? 6,5 cm

? 27,2 cm

24,1 cm

19,7 cm

24

0.269

1.461

MCNA 7465

55 cm**

9,6 cm

3,9 cm

25 cm

18,8 cm **

14 cm **

17

0.257

2.461

ULNA
 

Length

Max. Φ

Min. Φ

Per.

MPW

MDW

RI

   

MCNA 3157

11,43 cm

1,75 cm

1,45 cm

6,2 cm

5,09 cm

2,72 cm

0.279

   

TABLE 4. Measurements of the best-preserved specimens (in cm) of the pelvic girdle of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous of Laño (northern Spain). Abbreviations: *: eroded edges; APL ac: anteroposterior length of the acetabular surface; Max. APL prxb: maximum anteroposterior length of the proximal blade; Max./Min. L foramen: maximum/minimum length of the foramen; Min. APLdb: minimum anteroposterior length of the distal blade.

 

PUBIS

 

Total Length

Max. APL prxb

Min. APL db

APL ac

Max. L foramen

Min. L foramen

MCNA 7467

53,5*

18.5

6.1

8.5

3.6

2.1

TABLE 5. Measurements of the best-preserved specimens (in cm) of the hindlimb of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous of Laño (northern Spain). The measures with a ? symbol are approximate as iron oxides cover the surface of the bones. Abbreviations: **: eroded proximal and/or distal ends; ECC = femoral mid-shaft width/femoral anteroposterior width (Wilson and Carrano, 1999); Max. Φ: maximum diameter in the narrowest part of the diaphysis; Max. MLW D/Prx: maximum mediolateral width of the distal/proximal end; MDW: maximum width of the distal end; Min. Φ: minimum diameter in the narrowest part of the diaphysis; MLW: mediolateral width; MPW: maximum width of the proximal end; Per: perimeter in the narrowest part of the diaphysis; RI = average of the greatest widths of the proximal end, mid-shaft and distal end of the element/length of the element (Wilson and Upchurch, 2003).

 

FEMORA

 

Length

Max. Φ

Min. Φ

Per.

MPW

MDW

RI

ECC

MCNA 1817

-

9,2 cm

4,8 cm

24,8 cm

-

-

-

1.916

MCNA 3160

71,1 cm**

11,1 cm

4,3 cm

27,7 cm

-

17,5 cm

-

2.581

MCNA 7468

68,2 cm

9,1 cm

5,4 cm

25,2 cm

18,3 cm

17,6 cm

0.219

1.685

MCNA 14465

68 cm

9,2 cm

4,3 cm

24,1 cm

15,9 cm

17,7 cm

0.209

2.139

MCNA 14466

81,6 cm

12,1 cm

5,3 cm

33 cm

22,5 cm

-

-

2.283

MCNA 14468

75 cm**

13,8 cm

5,2 cm

35,2 cm

23,6 cm**

-

-

2.654

                 

TIBIAE

               
 

Length

Max. Φ

Min. Φ

Per.

MPW

MDW

RI

 

MCNA 2203

-

7,7 cm

4,1 cm

21,4 cm

-

10,2 cm

-

 

MCNA 13860

41,2 cm

5,7 cm

3,3 cm

17,6 cm

13,9 cm

9,7 cm

0.237

 
                 

FIBULAE

               
 

Length

Max. Φ

Min. Φ

Per.

MPW

MDW

RI

 

MCNA 7472

55 cm**

? 5 cm

? 3,5 cm

? 15 cm

10,2 cm

7,3 cm

0.136

 

MCNA 9410

51,4 cm**

4,6 cm

3,8 cm

14,1 cm

-

? 7,3 cm

-

 

MCNA 14469

47,5 cm**

6,6 cm

3,6 cm

-

-

-

-

 

MCNA 14471

42,3 cm

4,4 cm

2,8 cm

13,5 cm

10,3 cm

6,5 cm

0.167

 
                 

METATARSAL

               
 

Total Length (medial view)

Total Length (lateral view)

MLW

Max. MLW Prx

Max. MLW D

     

MCNA 14474

19.4

19.8

4.9

1.8

1.9

     
 

Verónica Díez Díaz. This email address is being protected from spambots. You need JavaScript enabled to view it.
vddUniversidad del País Vasco/Euskal Herriko Unibertsitatea
Facultad de Ciencia y Tecnología
Apdo. 644
48080 Bilbao
Spain

Verónica Díez Díaz graduated in Biology at the Universidad Autónoma de Madrid, and she completed her PhD in the Universidad del País Vasco/Euskal Herriko Unibertsitatea, both from Spain. Her main line of research is the diversity,systematics and palaeobiogeography of the titanosaurian sauropods, more specifically the ones from the Ibero-Armorican Island (Spain and south France in the Late Cretaceous).

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Xabier Pereda Suberbiola. This email address is being protected from spambots. You need JavaScript enabled to view it.
xpsUniversidad del País Vasco/Euskal Herriko Unibertsitatea
Facultad de Ciencia y Tecnología
Apdo. 644
48080 Bilbao
Spain

Xabier Pereda Suberbiola has a permanent research position at the Universidad del País Vasco/Euskal Herriko Unibertsitatea. Most of his research projects are devoted to Mesozoic Vertebrate Palaeontology, more specifically dinosaurs.

divider

José Luis Sanz. This email address is being protected from spambots. You need JavaScript enabled to view it.
jlsUniversidad Autónoma de Madrid
Facultad de Ciencias
Dpto. Biología
Ud. Paleontología
28049 Cantoblanco
Madrid
Spain

José Luis Sanz is Professor at the Universidad Autónoma de Madrid. He has worked on nothosaurs and several linages of dinosaurs, especially sauropods and ornithopods. Nowadays his main research projects are related with theropod and avian evolution. 

 

FIGURE 1. Map showing the geographic location of the Laño quarry.

figure 1

FIGURE 2. Scapular girdle bones of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous of Laño (northern Spain). Left scapula (MCNA 7459) in 1. lateral and 2. medial views. Right scapula (MCNA 14461) in 3. medial view. Left coracoid (MCNA 3158) in 4. lateral and 5. medial views. Right coracoid (MCNA 7460) in 6. medial and 7. lateral views. Right sternal plate in 8. dorsal and 9. ventral views.Abbreviations: ant, anterior; cf, coracoid foramen; gl, glenoid; lat, lateral; pr, prominence, rd, ridge.

figure 2

FIGURE 3. Forelimb bones of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous of Laño (northern Spain). Left humerus (MCNA 7463) in 1. anterior and 2. posterior views. Right humerus (MCNA 7462) in 3. anterior and 4. posterior views. Right ulna (MCNA 3157) in 5. lateral, 6. medial, 7. proximal and 8. distal (lateral towards bottom) views. Abbreviations: dpc, deltopectoral crest; ol, olecranon; raa, radial articulation.

figure 3

FIGURE 4. Pelvic girdle bonesof the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous of Laño (northern Spain). Left ilium (LDL 12) in 1. lateral view. Right ilium (MCNA 7466) in 2. lateral view. Right ilium (MCNA 8609) in 3. lateral view. Left pubis in 4. medial view. Abbreviations: acet, acetabulum; ilped, iliac peduncle; isped, ischial peduncle; ho, hollow; of, obturator foramen; pped, pubic peduncle.

figure 4

FIGURE 5. Hindlimb bones of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous of Laño (northern Spain). Left femur (MCNA 7468) in 1. anterior, 2. lateral, 3. posterior, 4. proximal (posterior towards top) and 5. distal (posterior towards top) views. Left tibia (MCNA 13860) in 6. lateral, 7. medial, 8. proximal (medial towards top) and 9. distal (medial towards top) views. Right fibula (MCNA 9410) in 10. lateral, 11. medial, 12. posterior and 13. distal (posterior towards top) views. Abbreviations: aspa, articular surface for the ascending process; cc, cnemial crest; fic, fibular condyle; ft, fourth trochanter; lt, lateral trochanter; tic, tibial condyle; pvp, posteroventral process; ts, trochanteric shelf.

figure5

FIGURE 6. Leftmetatarsal III (MCNA 14474) of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous of Laño (northern Spain) in 1. plantar, 2. lateral, 3. dorsal, 4. medial, 5. proximal and 6. distal views (dorsal towards top).

figure 6

FIGURE 7. Osteoderms (MCNA 14473 and 14474) of the titanosaurian sauropod Lirainosaurus astibiae from the Late Cretaceous of Laño (northern Spain).

figure 7