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| Lohuecotitan pandafilandi
Díaz, Mocho, Páramo, Escaso, Marcos-Fernández, Sanz & Ortega, 2016
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Abstract
The upper Campanian-lower Maastrichtian site of Lo Hueco (Cuenca, Spain) has provided a set of well-preserved partial skeletons in anatomical connection or with a low dispersion of their skeletal elements. One partial skeleton is herein described and a new titanosaurian sauropod is established, Lohuecotitan pandafilandi. This titanosaur is diagnosed by eight autapomorphic features: dorsally and ventrally widened or bifurcated posterior centrodiapophyseal lamina in anterior and middle dorsal vertebrae; short postspinal lamina with a transversely expanded distal end represented by smooth scars in the dorsal vertebrae; anteriormost caudals with the medial spinoprezygapophyseal and medial spinopostzygapophyseal laminae ventrally connected with the prespinal and postspinal laminae, respectively; anterior caudal neural spines with a dorsal projection of the prespinal and postspinal laminae; anterior caudal neural spines bears a “greek-cross”-like cross-section; middle caudal centra having two round and rough structures in the dorsal edge of the posterior articulation, which extends to the dorsal surface of the centrum; the articular ends of the rami of the haemal arches are divided in two articular surfaces; and tuberosity between the anterior and the lateral trochanter of the fibula. The herein performed phylogenetic analysis considered L. pandafilandi as a member of Lithostrotia more derived than Malawisaurus. The known palaeodiversity of the Late Cretaceous Ibero-Armorican titanosaurs is increasing, and further analyses focused on this group will be necessary to better understand the evolutionary history of European titanosaurs and to clarify their relationships within Titanosauria.
Keywords: Lohuecotitan pandafilandi gen. et sp. nov.; Titanosauria; Lithostrotia; Spain; Late Cretaceous
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Illustration: Francesc Gascó & Eloy Manzanero
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Systematic palaeontology
Dinosauria Owen, 1842
Saurischia Seeley, 1888
Sauropoda Marsh, 1878
Titanosauriformes Salgado et al., 1997
Titanosauria Bonaparte and Coria, 1993
Lithostrotia Upchurch et al., 2004
Lohuecotitan gen. nov.
Type and only included species. Lohuecotitan pandafilandi sp. nov.
Etymology. Lohuecotitan from Lo Hueco (the type locality) and titan (the giants of the Greek mythology).
Lohuecotitan pandafilandi gen. et sp. nov.
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| Fig. 5. Sacrum and anterior sector of the Lohuecotitan pandafilandi type specimen (HUE-EC-01) in articulation (A). Appendicular bones of L. pandafilandi type specimen (HUE-EC-01): left ulna (HUE-03044) in lateral (B) and proximal (C) views; right femur (HUE-03108) in distal (D) and posterior (G) views; right ischium (HUE-03099) in lateral view (E); left pubis (HUE-03086) in anterior view (F); right fibula (HUE-03087) in proximal (H) and lateral (J) views; right tibia (HUE-03082) in proximal (I) and posterior (K) views. Scale bar: 10 cm. |
Holotype. A partial skeleton disarticulated, but whose remains had low dispersion in the field. The complete set is referred as HUE-EC-01 and is composed of: three cervical vertebrae and neural arch fragments (HUE-03128, 03076, 03077, 03136); six dorsal vertebrae (HUE-03088, 03134/7, 03135); dorsal ribs (HUE-03045, 03081, 10017); sacral vertebrae fragments (HUE-03134); 20 caudal vertebrae (HUE-03020-29, 03052, 03101, 03114, 03134/1-6); haemal arches (HUE-03032-34, 03040, 03041, 03054, 03134/17, 03134/19); left ulna (HUE-03044); left and right ischia (HUE-03099, 03134/15); left pubis (HUE-03086); right femur (HUE-03108); right fibula (HUE-03087); right tibia (HUE-03082), and several other indeterminate remains (HUE-3043, 3046, 3067, 3083, 3084).
Etymology. The specific name pandafilandi refers to Pandafilando de la fosca vista, one of the characters in the novel “The Ingenious Gentleman Don Quixote of La Mancha” (El ingenioso hidalgo don Quijote de la Mancha) written by Miguel de Cervantes and published in the early seventeenth century. Pandafilando is, in the mind of the protagonist, a giant against who he must fight.
Type locality and horizon. The Lo Hueco fossil site (Fuentes, Cuenca, Castilla-La Mancha, central Spain) ( Fig. 1), Margas, Arcillas y Yesos de Villalba de la Sierra Formation, upper Campanian-lower Maastrichtian.
Diagnosis. Member of Titanosauria, having the following autapomorphies (marked with an asterisk), as well as an unique combination of characters not seen in other titanosaurs: (1) posterior centrodiapophyseal lamina (pcdl) dorsally and ventrally widened (sometimes bifurcated) simultaneous in anterior and middle dorsal vertebrae (shared with Saltasaurus); (2) short postspinal lamina (posl) with a transversely expanded distal end represented by smooth scars in the dorsal vertebrae*; (3) anteriormost caudal vertebrae with the medial spinoprezygapophyseal lamina (med. sprl) and medial spinopostzygapophyseal lamina (med. spol) ventrally connected with the prespinal lamina (prsl) and posl, respectively*; (4) anterior neural spines on caudal vertebrae with a dorsal projection of the prsl and posl, resulting V-shaped outline in lateral view*; (5) anterior neural spines on caudal vertebrae bear a “greek-cross”-like cross-section*; (6) middle caudal vertebrae having two rough structures in the dorsal edge of the posterior articulation, which extends to the dorsal surface of the centrum*; (7) the articular ends of the rami of the posterior haemal arches are fully divided in two articular facets*; (8) tuberosity between the anterior and the lateral trochanter of the fibula (shared with Jainosaurus).
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Conclusion
A new titanosaur, Lohuecotitan pandafilandi is described from the Upper Cretaceous of the Ibero-Armorican Island. This new taxon came from the Lo Hueco fossil site (upper Campanian-lower Maastrichtian). This taxon is diagnosed by eight autapomorphic features highlighting the presence of short posl with a transversely expanded distal end represented by smooth scars in the dorsal vertebrae; anteriormost caudals with the med. sprl and med. spol ventrally connected with the prsl and posl, respectively; anterior neural spines with prsl and posl dorsally projected; double articular facets of the rami of the distal haemal arches.
Lohuecotitan is placed within Lithostrotia, and this position is supported by the presence of anterior and middle dorsal vertebrae with strongly and posteroventrally oriented (more than 40°) zygapophyseal articulation. Lohuecotitan is considered a more derived lithostrotian than Malawisaurus and is recovered in a polytomy with Opisthocoelicaudia, Alamosaurus, Trigonosaurus, Saltasaurinae and Nemegtosauridae. The phylogenetic relationships of the Ibero-Armorican titanosaurs remain uncertain. Future analyses focused on European titanosaur taxa will be important to better understand the evolutionary history of this group in the European territory and to clarify the relationships of these taxa with non-European titanosaurs.
Previous works confirm a high titanosaurian diversity in the Ibero-Armorican Island summarizing the recent discoveries from Spain and France: from one known titanosaurian taxon in Spain (Lirainosaurus) and two in France (Ampelosaurus and Atsinganosaurus) to, at least, six or seven taxa ( Díez Díaz et al., 2015). The diagnosis of Lohuecotitan is relevant to begin to update the titanosaurian diversity of Europe, and more specifically of the Iberian Peninsula.
V. Díez Díaz, P. Mocho, A. Páramo, F. Escaso, F. Marcos-Fernández, J.L. Sanz and F. Ortega. 2016. A New Titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous of Lo Hueco (Cuenca, Spain). Cretaceous Research. DOI: 10.1016/j.cretres.2016.08.001
