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A new trackway possibly made by a trotting theropod at the Las Hoyas fossil site (Early Cretaceous, Cuenca province, Spain): identification, bio-dynamics and palaeoenvironmental implications

J.J. Moratalla, J. Marugán-Lobón, H. Martín-Abad, E. Cuesta and A.D.

Plain Language Abstract

The main objective of this work is to describe and to analyze a new dinosaur trackway found at Las Hoyas (Lower Cretaceous, province of Cuenca, Spain), a locality interpreted as an ancient wetland. This study is focused on its morphological description, locomotion features, dinosaur identification, track preservation, and also the distribution of vertebrate tracks through the Las Hoyas stratigraphic succession.

The dinosaur trackway consists of four shallow footprints. Their morphological features (tridactyl prints, slender and acuminate digits, V-shaped central digit, etc.) strongly suggest that the tracks were produced by a bipedal theropod dinosaur. The footprint size indicates that the trackmaker was a dinosaur of medium size (about 135 cm of hip height and about 4-4.5 m long). The mean stride length reveals that the trackmaker was moving rather fast, about 12 km/h. This speed indicates a trotting behavior, but probably not a real running movement.
The size of the footprints suggests the presence of a theropod dinosaur that would fit with the size of the carcharodontosaurid Concavenator corcovatus, an almost complete skeleton of which was also found at the Las Hoyas locality. In fact, the foot and hindlimb lengths of Concavenator (estimated from its preserved skeleton) are quite similar to those values estimated from the studied trackway.

The distribution of the dinosaur trackway described here as well as other previously described tracks from Las Hoyas show that vertebrate prints become more abundant toward the top of the Las Hoyas stratigraphic succession. However, the big vertebrates, such as dinosaurs and crocodiles, were walking or crossing a shallow ponding area as incidental organisms.

Resumen en Español

Nuevo rastro de un terópodo posiblemente trotando en el yacimiento de Las Hoyas (Cretácico Inferior, provincia de Cuenca, España): identificación, biodinámica e implicaciones paleoambientales

Las icnitas de dinosaurios recientemente descubiertas en el yacimiento de Las Hoyas han despertado un renovado interés hacia los icnofósiles como elementos de ayuda para la interpretación de las paleocomunidades y también del paleoambiente de esta área. La variedad morfológica de las icnitas del yacimiento parece haber estado influida por la presencia de tapetes microbianos, contemporáneos a su formación. Este trabajo es una puesta al día de las huellas de tetrápodos del yacimiento, con la descripción de un nuevo rastro de dinosaurio constituido por cuatro icnitas tridáctilas. Aunque este rastro no está excepcionalmente bien preservado, la morfología de los dedos, la superficie plantar así como la forma general de las icnitas sugiere que éstas fueron producidas por un dinosaurio terópodo de tamaño medio. Por otro lado, la relación entre la longitud de zancada y la altura teórica de la extremidad sugiere que el dinosaurio productor se movía al trote. El hecho de que estas huellas presenten un tamaño similar al del pie de Concavenator -un dinosaurio carcarodontosáurido cuyo esqueleto ha sido hallado en el mismo yacimiento- es un detalle muy interesante. Esta nueva evidencia icnológica revela que las icnitas de tetrápodos son más abundantes hacia la parte superior de la columna estratigráfica. Este hecho sugiere, a su vez, que el yacimiento evolucionó en el tiempo hacia períodos secos más frecuentes –siendo así más fácil caminar por áreas de aguas más someras y permitiendo incluso a los grandes dinosaurios poder atravesar la zona pantanosa de Las Hoyas.

PALABRAS CLAVE: Barremiense; Carcarodontosáurido; icnitas; dinosaurio trotando; tapetes microbianos; tafonomía.

Traducción: by author

Résumé en Français

in progress

Translator: Antoine Souron

Deutsche Zusammenfassung

Neue Trittsigel eines möglicherweise rennenden Theropoden aus der Las Hoyas Fundstelle (frühe Kreide, Cuenca Provinz, Spanien): Identifizierung, Bio-Dynamik und Auswirkungen auf die Paläoumwelt

Die in der Las Hoyas Fundstelle kürzlich identifizierten Dinosaurier-Spuren haben das Interesse an Spurenfossilien wieder angefacht, da sie helfen Paläoumwelt und Paläogemeinschaft zu interpretieren. Die verschiedenen Tetrapoden-Abdrucksmorphologien scheinen durch das gleichzeitige Auftreten von Bakterienmatten beeinflusst zu sein. Diese Arbeit aktualisiert die Informationen über Tetrapoden-Spuren aus der Fundstelle und beschreibt eine neue Dinosaurier-Spur, die vier tridactyle Abdrücke enthält. Auch wenn die Spur nicht besonders gut erhalten ist, weisen die Morphologie der Krallenmarken, die Ferse und die generelle Morphologie stark auf einen mittelgroßen theropoden Dinosaurier hin. Darüber hinaus signalisiert das Verhältnis von Schrittlänge und angenommener Hüfthöhe, dass der Spurenverursacher rannte. Interessanterweise haben die Spuren eine ähnliche Größe wie die Füße von Concavenator, ein carcharodontosaurider Dinosaurier, von dem aus derselben Lokalität Skelettmaterial bekannt ist. Dieser neue ichnologische Nachweis zeigt, dass Tetraopden-Trittsigel häufiger gegen das Top der stratigraphischen Abfolge hin auftreten. Dies deutet darauf hin, dass das Ökosystem im Laufe der Zeit immer mehr trockene Perioden hatte und so die Dinosaurier vor Ort in der Lage waren durch Flachwassergebiete zu laufen bzw. große Dinosaurier wateten durch den Wasserbereich von Las Hoyas.


Schlüsselwörter: Barremium; Carcharodontosaurider Dinosaurier; Fußspuren; rennender Dinosaurier; Bakterienmatten; Taphonomie

Translator: Eva Gebauer

Arabic

Translator: Ashraf M.T. Elewa

 

 

FIGURE 1. 1. Location of the Southwestern Iberian Ranges on the Iberian Peninsula. 2. Lithostratigraphic units of the Cretaceous of Iberian Basin. 3. Informal stratigraphy of La Huérguina Limestones Fm. in Las Hoyas and surrounding sub-basins (modified from Fregenal-Martínez and Meléndez, 2000).

 figure 1

FIGURE 2. Map of the Las Hoyas quarry (upper Barremian, Cuenca, Spain) with the position of the E-W excavated Squares, in color (modified from Buscalioni and Fregenal-Martínez, 2010). As shown in the box, the stratigraphic succession of the squares, and the associated richness in the number of tetrapod tracks.

figure 2 

FIGURE 3. Preservation of tetrapod traces at Las Hoyas (Late Barremian, La Huérguina Formation). 1. Stretched isolated footprint (MCCM-LH- 6500) that was formerly attributed to Pteraichnus. 2. Dinosaur footprint of a trackway composed of two prints in White Square layer #8.2, showing a chipped surface inside; scale bar 15 cm. 3. Theropod left footprint of the trackway recorded in Magenta Square. 4. Theropod right footprint of the same trackway as Figure 3.3 recorded in Magenta Square. 5. Hand and foot of a crocodylomorph recorded in White Square, layer #5, scale bar 13 cm. The image has been equalized to enhance the scratches of the foot toes. 6. Traces attributed to undetermined tetrapod preserved as sub-elliptical prints closely placed from MaWh Corridor (LH-29959).

 figure3 a

FIGURE 4. Drawing of the distorted footprint MCCM-LH 6500 (Las Hoyas, Late Barremian) showing the taphonomic features of a print likely produced on a moist to unsaturated microbial mat. 1-3: layers of sediment fill that form a stack of internal overtracks; dr: displacement rim; rf: radial fissures or striation marks.

figure 4 

FIGURE 5. Measurements used in this study. 1. Variables related to a footprint: FL, footprint length; FW, footprint width; LII, LIII, LIV, length of the digits; II-III, angle between the axis of digit II and digit III; III-IV, the same angle relative to digits III and IV; TE, toe extension, that is, the anterior projection of digit III. 2. Variables related to a trackway: ANG, angle between three consecutive footprints; eTW, external trackway width; iTW, internal trackway width; PL, pace length; SL, stride length.

 figure 5

FIGURE 6. 1. Photograph of the trackway LH-Y-1-001 of the Late Barremian of Las Hoyas outcrop (La Huérguina Formation). 2. Footprint LH-Y-1-001/1. 3. Footprint LH-Y-1-001/2. 4. Footprint LH-Y-1-001/3.

figure6 a 

FIGURE 7. Map of the trackway LH-Y-1-001 from the Las Hoyas fossil site Late Barremian (La Huérguina Formation).

figure 7

 

 

TABLE 1. Track measurements for the trackway LH-Y-1-001 from the Las Hoyas fossil locality. Rot, angle between the track and the trackway midlile (negative value implies inward rotation). H, hip height sensu Thulborn (1990). The rest of variables as in the Figure 5.1.

Track FL FW LII LIII LIV TE II-III III-IV II-IV FL-FW/FW Rot H
1 13 15   11 5     41º   (-) 0.13 -11º  
2 28 24 4.5 7.5 2.5 6.25 11º 20º 0.16 137.2
3 27 24 6.2 12.7 10.5 10 18º 24º 39º 0.12 -4º 132.3
4 26 22 8 12.5 8 5.5 24º 26º 46º 0.18 -12º 127.4
Mean 27.5 24 5.35 10.1 6.5 8.12 14.5º 16.5º 29.5º 0.14 -6.7º 134.75

 

TABLE 2. Trackway measurements from the trackway LH-Y-1-001 from the Las Hoyas fossil locality. H, hip height sensu Thulborn (1990); V, speed of progression (km/h); DIR, trackway direction. The rest of the measurements as in Figure 5.2 and Table 1.

Tracks SL PL ANG SL/H SL/FL eTW iTW iTW/FW V DIR
1-3 292   151º   10.61          
2-4 317   157º   11.52          
1-2   138                
2-3   165                
3-4   156                
Mean 304.5 153 154º 2.26 11.06 53.7 16.2 0.67 12.7 234º

 

 

author 1J.J. Moratalla. Instituto Geológico y Minero de España (Igme), Museo Geominero, Ríos Rosas 23, 28003 Madrid, Spain. This email address is being protected from spambots. You need JavaScript enabled to view it.

Ph.D. Scientific Researcher (paleontology) in the Instituto Geologico y Minero de España (IGME) (Museo Geominero), Madrid, Spain, -Spanish Geological Survey-. The research has been mainly focused on dinosaur trace fossils (tracks and eggs). The author has discovered, excavated and studied many dinosaur tracksites from the Cameros Basin (Lower Cretaceous, La Rioja province, Spain). So, the main focuss of his research is related with dinosaur paleoichnology and its implications: locomotion, identification, preservation, paleobiogeographical implications, etc. Today, he is part of the Research Team on the Las Hoyas locality, with publications on birds and pterosaur bone record.

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author 2J. Marugán-Lobón. Unidad de Paleontología, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain and Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA, USA. This email address is being protected from spambots. You need JavaScript enabled to view it.

Ph.D. Paleontologist from the Paleontology Department of the Universidad Autonoma de Madrid (Spain). His work has been focused on the application of Geometric Morphometrics tools to vertebrate comparative anatomy, ontogenic development, evolution and phylogeny, of Cretaceous birds, pterosaurs, and mammals. Today he is part of the Work Team at Las Hoyas fossil site.

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author 3H. Martín-Abad. Jurassica Museum, Route de Fontenais 21, 2900 Porrentruy, Switzerland. This email address is being protected from spambots. You need JavaScript enabled to view it. and Department of Geosciences, University of Fribourg, Chemin du Musée 6, 1700 Fribourg, Switzerland

Ph.D. Paleontologist from the Paleontology Department of the Universidad Autonoma de Madrid (Spain). His work has mainly been focused on the study of Cretaceous fishes from the Las Hoyas fossil site, their evolution, paleoecology and paleobiogeographical implications. Today he is part of the Work Team at Las Hoyas fossil site.

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author 4E. Cuesta. Unidad de Paleontología, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain. This email address is being protected from spambots. You need JavaScript enabled to view it.

Ph.D. Paleontologist from the Paleontology Department of the Universidad Autonoma de Madrid (Spain). Her work has been focused on theropod dinosaurs, mainly on the carcharodontosaurid Concavenator corcovatus, from the Las Hoyas fossil site. Today she is part of the Work Team at Las Hoyas fossil site.

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author 5A.D. Buscalioni. Unidad de Paleontología, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain. This email address is being protected from spambots. You need JavaScript enabled to view it..

Ph.D. Paleontologist from the Paleontology Department of the Universidad Autonoma de Madrid (Spain). She is today responsible of the Direction of the Work Team at Las Hoyas fossil site. Her work has mainly been focused on phylogeny, evolution and paleoecology of Mesozoic continental vertebrates, mainly crocodiles, dinosaurs, birds, pterosaurs, etc.