A new titanosaur from the La Colonia Formation (Campanian-Maastrichtian), Chubut Province, Argentina

Figures & data

Figure 1. Location map of the site of the discovery of the holotype of Titanomachya gimenezi. Modified from Sterli et al. (2022)

Figure 2. Geological columns of the La Colonia Formation, at Norte de Cerro Bayo, the area of the discovery of the holotype of Titanomachya gimenezi. Modified from Sterli et al. (2022)

Figure 3. Skeletal reconstruction of Titanomachya gimenezi. Preserved bones shown in light blue. Reconstruction by Gabriel Lio.

Figure 4. Spatial distribution of Titanomachya gimenezi skeletal elements.

Figure 5. Titanomachya gimenezi, holotype. MPEF Pv 11547/10. Posterior caudal vertebra in A, posterior; B, right lateral; C, anterior; D, dorsal and E, ventral views. Abbreviations: lr, longitudinal ridge. Scale bar = 5 cm.

Table 1. Measurements of the elements of the axial skeleton of Titanomachya gimenezi.

Main measurements	Caudal vertebra	Haemal arches
	MPEF-Pv -11547/10	MPEF-Pv -11547/11	MPEF-Pv -11547/12
Centrum length	11	-	-
Height of the centrum on the anterior face	6.2	-	-
Height of centrum on posterior face	6.02	-	-
Height of haemal canal	-	6.45	5.8
Width of centrum on front face	7.22	-	-
Width of centrum on posterior face	7.4	-	-
Total height	9.7	22.4	15.15
High of the neural arch	4.2	-	-
Width of the neural arch	5.22	-	-
Length of neural arch	4.59	-	-

Figure 6. Titanomachya gimenezi, holotype. MPEF pv 11547/11 and 12. Middle haemal arch A, right lateral; B, anterior views. Anterior haemal arch C, right lateral; D, anterior views. Scale bar = 10 cm.

Figure 7. Titanomachya gimenezi, holotype. MPEF Pv 11547/14/1–6. Thoracic ribs fragments. MPEF Pv 11547/1 in A, external and B, internal views. MPEF Pv 11547/2 in C, external view. MPEF Pv 11547/3 in D, external and E, internal views. MPEF Pv 11547/4 in F, external and G, internal views, MPEF Pv 11547/5 in H, external and I, internal views, MPEF Pv 11547/6 in J, internal; K, proximal; L, anterior; M, external and N, posterior views. Scale bar = 30 cm.

Figure 8. Titanomachya gimenezi, holotype. MPEF Pv 11547/7, left humerus in A, posterior; B, proximal; C,distal; D, medial and E, anterior views. Abbreviations: cb, coracobrachialis origin scar; dc, deltopectoral crest; hh, humeral head; lc, lateral condyle; ld, latissimus dorsi insertion scar; mc, medial condyle; scf, supracondylar fossa; suc, supracoracoid insertion scar. Scale bar = 10 cm.

Table 2. Measurements of the forelimb of Titanomachya gimenezi.

Main measurements	Humerus
	MPEF 11547/7
Proximodistal length	64.54
Anteroposterior width of proximal end	7.5
Mediolateral width of the proximal end	27.30
Anteroposterior width at the mid-diaphysis	6.54
Mediolateral width at the mid-diaphysis	12.83
Anteroposterior width of the distal end	13.50
Mediolateral width of distal end	21.70
Length of the medial condyle of the humerus	13
Width of the medial condyle of the humerus	7.90
Length of lateral condyle of humerus	13.5
Width of the lateral condyle of the humerus	9.64
Distance from the proximal end to the most prominent point of the deltopectoral crest	22.5
Projection of the deltopectoral crest from the anterior surface	7.04
Circumference of the humerus at the mid-diaphysis	38.5

*Incomplete measurement due to damage.

Table 3. Measurements of femora and tibiae of Titanomachya gimenezi.

Medidas principales	Femora		Tibiae
	MPEF 11547/1	MPEF 11547/2	MPEF 11547/4	MPEF 11547/6
Proximodistal length	88.5	27.4*	61.4	61
Anteroposterior width of proximal end	10.4	-	12.3	12
Mediolateral width of the proximal end	25	-	16.5	14.8
Anteroposterior width at mid-diaphysis	8	-	9	7.5
Mediolateral width at the mid-diaphysis	15.5	-	9.3	10
Anteroposterior width of the distal end	14.8	14.9	11.5	10.39
Mediolateral width of the distal end	22.3	22.4	19.3	19.2
Distance from the fourth trochanter to the femoral head	39.3	-	-	-
Distance of fourth trochanter from lateral side of femur	13.7	-	-	-
Circumference at midshaft	42.5	-	-	-
Width at the level of the protuberance	22.4	-	-	-
Width of medial condyle	7	7.8	-	-
Width of lateral condyle	7.5	9.2	-	-
Anteroposterior length of posterolateral process at distal end	-	-	11.2	8
Latero-medial length of posterolateral process at distal end	-	-	8.6	2.8
Anteroposterior length of anterolateral process at distal end	-	-	6.7	5.9
Latero-medial length of the anterolateral process at the distal end.	-	-	5.4	7.3
Dorsoventral length of the cnemial crest	-	-	11.8	20
Maximum anteroposterior length of the cnemial crest	-	-	2.4	3.4

*Broken.

Figure 9. Titanomachya gimenezi, holotype. MPEF Pv 11547/15, left ilia fragment in A, external and B, internal views. Abbreviations: isped, ischial peduncle; poap, postacetabular process. Scale bar = 15 cm.

Figure 10. Titanomachya gimenezi, holotype. MPEF Pv 11547/13, indeterminated pube fragment in external view. Scale bar = 20 cm.

Figure 11. Titanomachya gimenezi, holotype. MPEF Pv 11547/1, right femur in A, anterior; B, proximal; C, medial; D, posterior and E, distal views. Abbreviations: fh, femoral head; gt, greater trochanter; lb, lateral bulge; lec, lateral epicondyle; lc, lateral condyle; mc, medial condyle; pr, posterior ridge; 4t, fourth trochanter. Scale bar = 20 cm.

Figure 12. Titanomachya gimenezi, holotype. Tibiae: (a-d) left tibia MPEF 11547/6 in A, anterior; B, distal; C, lateral and D, proximal views. Abbreviations: cc, cnemial crest; cf, cnemial fossa; lc, lateral condyle; pc, posterior condyle. Scale bar = 10 cm.

Figure 13. Titanomachya gimenezi, holotype. Fibulae. MPEF 11547/5 left fibula in A, lateral; B, distal; C, proximal, and D, posterior views. MPEF 11547/3 right fibula in E, medial; F, proximal and G, lateral views. Abbreviations: lt, lateral tuberosity. Scale bar = 10 cm.

Table 4. Measurements of fibulae and astragalus of Titanomachya gimenezi.

Main mesurements	Fibulae		Astragalus
	MPEF 11547/5	MPEF 11547/3	MPEF 11547/8	MPEF 11547/9
Proximodistal length	62.5	61.5	9.5	8.5
Anteroposterior width of proximal end	10.5	16.5	12	13
Mediolateral width of the proximal end	11.2	6.5	6.6	8.3
Anteroposterior width at the mid-diaphysis	7.6	7.4	-	-
Mediolateral width at the middle diaphysis	5.1	5.7	-	-
Anteroposterior width of the distal end	8.7	11.4	11.7	11.2
Mediolateral width of distal end	9.7	7.5	22.4	18.7*
Dorsoventral length of lateral trochanter	7.7	10.3	-	-
Anteroposterior length of the lateral trochanter	4.5	5.2	-	-
Lateromedial length of lateral trochanter	2.9	2.9	-	-

Broken*.

Figure 14. Titanomachya gimenezi, holotype. MPEF 11547/9. Left astragalus in A, anterior; B, dorsal; C, posterior; D, ventral; E, fibular and F, medial views. asp, ascending process. Scale bar = 5 cm.

Figure 15. Titanomachya gimenezi, holotype. MPEF 11547/8. Right astragalus in A, anterior; B, dorsal; C, posterior; D, ventral; E, fibular and F, tibial views. Abbreviations: asp, ascending process; fs, fibular surface; hb, hemispherical bulge; ts, tibial surface. Scale bar = 5 cm.

Figure 16. Strict consensus of the phylogenetic analysis. Matrix based on that of Pérez Moreno et al. (2023).

Figure 17. Schematic drawings of the morphologies of astragalus within Titanosauria in all its views. A, diagram of the typical colossosaurianian astragalus and its articulation with tibia and fibula. B, diagram of the typical saltasaurioid astragalus and its articulation with tibia and fibula. C, diagram of the astragalus of Titanomachya and its articulation with the tibia and fibula.

Sterli J, Parras A, Albino A, Becerra MG, Carballido JL, Gouiric-Cavalli S, Muzzopappa P, Oriozabala C, Panzeri KM, Pérez Moreno A, et al. 2021 2022. Vertebrados continentales de la Formación la Colonia (Campaniano-Maastrichtiano). In: En Giacosa R, editor. Relatorio XXI CGA Geología y Recursos Naturales de la provincia del Chubut; p. 834–865.

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Pérez Moreno A, Otero A, Carballido JL, Salgado L, Calvo JO. 2023. The appendicular skeleton of Rinconsaurus caudamirus (Sauropoda: Titanosauria) from the Upper Cretaceous of Patagonia, Argentina. Cretaceous Res. 142:105389. doi: 10.1016/j.cretres.2022.105389.

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