Reconstructing the foraging environment of the latest titanosaurs (Fumanya dinosaur tracksite, Catalonia)

https://doi.org/10.1016/j.palaeo.2014.06.007Get rights and content

Highlights

  • Maastrichtian Fumanya dinosaur tracksites are among the most important worlwide.

  • Ichnology and plant taphofacies reveal two environments in a coastal area.

  • Taphonomical evidence suggests that titanosaurs congregated in coastal areas.

  • Data supports the hypotheses that titanosaurs also inhabited coastal environments.

Abstract

The analysis of depositional environments associated with sauropod dinosaurs has been revealed as a key element for assessing their palaeoecology. A detailed study of the sedimentology, plant taphofacies and titanosaur ichnology at the Fumanya localities (early Maastrichtian, Catalonia) reveals that two distinct palaeoenvironments existed within the coastal wetlands. These settings are correlated with the occurrence of two distinct track and plant remains distributions, which correspond to a) a marginal brackish lagoon environment where no vegetation grew and titanosaurs roamed, during a short time span, without apparently any preferential purpose, and b) a freshwater swamp area around charophyte lakes with evidence of vegetation growth (charophytes, palms, and probably ferns and cheirolepidiacean conifers) where titanosaurs congregated and fed actively during a long time span. These data indicate that titanosaurs trampled the muddy substrates of freshwater wetlands in order to forage according to the availability of plants.

Introduction

Over the last decades, greater understanding of sauropod palaeoecology has been achieved by the discovery of new fossils and the study of depositional environments associated with both bone and tracksites. Classical palaeoenvironmental analyses stated that sauropods inhabited a wide variety of environments, ranging from terrestrial (floodplain and fluvio-lacustrine settings) to coastal/nearshore settings (Sloan, 1969, Dodson et al., 1980, Russell et al., 1980, Lucas, 1981, Lehman, 1981, Lucas and Hunt, 1989). Studies on tracks and trackways suggested that sauropods frequently walked on submerged substrates in coastal and deltaic environments (Lockley et al., 1994) but later works rejected this possibility (Wright, 2005). Recent analysis of extensive datasets supported the first idea (i.e., Sloan, 1969, Lucas, 1981, among others) that sauropods were strongly linked to inland environments (Butler and Barrett, 2008). However, global quantitative analyses revealed a more complex scenario, with some clades (the non-titanosaur sauropods) linked to coastal environments (e.g. carbonate platforms), and others (the titanosaurs) linked to inland environments (e.g. fluvio-lacustrine systems) (Mannion and Upchurch, 2010). The titanosaurs appeared between the Middle and Late Jurassic, and underwent an extensive and apparently rapid radiation, to become the predominant sauropods of many terrestrial ecosystems throughout every landmass, before their extinction at the end of the Cretaceous (Barrett and Upchurch, 2005, Wilson, 2005).

The Fumanya titanosaur localities (early Maastrichtian, Tremp Formation, southeastern Pyrenees) display nearly 3000 footprints, arranged in more than 50 trackways (Viladrich, 1986, Le Loeuff and Martínez-Rius, 1997, Schulp and Brokx, 1999, Vila et al., 2005, Vila et al., 2008), and record a progression from marginal brackish lagoon to more protected freshwater palustrine settings. The Fumanya wetlands are thus an exceptional place to elucidate the titanosaurs' foraging behaviour and habitat preferences with respect to plant cover. Plant communities featured include diverse charophyte meadows in freshwater alkaline lakes and poorly-diversified charophyte assemblages in brackish lagoons (Villalba-Breva and Martín-Closas, 2011, Villalba-Breva et al., 2012). The freshwater swamps were vegetated by dense cheirolepidiacean conifer-arecacean wetlands, whilst the marginal lagoon was devoid of vegetation and only transported plant debris accumulated there (Villalba-Breva et al., 2012). Despite the fact that titanosaurs were documented in previous studies to inhabit fluvial settings, evidence from Fumanya show that their behaviour was more complex and specific to each sedimentary setting.

Section snippets

Geological and palaeontological setting

In the southern Pyrenees foreland basins, the Maastrichtian to Thanetian materials of the Tremp Formation (Mey et al., 1968) crop out in numerous localities within the Vallcebre, Coll de Nargó, Tremp and Àger synclines (north-eastern Iberian Peninsula). Most continuous series are exposed in the Vallcebre syncline, where they measure up to 760 m thick (Oms et al., 2007). Here, the lower boundary of the Tremp Formation corresponds to its contact with the near-shore calcarenitic limestones of the

Materials and methods

Titanosaur tracks in Fumanya appear at several stratigraphic horizons (Fig. 1; Vila et al., 2013). Data were collected from four track levels (I, II, IIIa and IIIb in Fig. 1, Fig. 2). Track levels I and III displayed the best and most extensive exposures. A surface of 7200 m2 from track level I was divided into a grid with squares of 400 m2. Tracks were counted for each square, and mean track density was calculated. Similarly, track density was calculated for track levels IIIa and IIIb in

Sedimentological and taphonomic evidence

Track level I is the lowest track-bearing bed in the Fumanya localities and crops out through a vast surface of nearly 35,000 m2 at the Fumanya Sud, Mina Esquirol, Fumanya Nord and Mina Tumí sites (Fig. 1, Fig. 3, Fig. 4, Fig. 5; Vila et al., 2005, Vila et al., 2008). It corresponds to the base of the ‘Middle Grey Garumnian’ of Villalba-Breva et al. (2012) and it is overlaid by the first coal seam of the Fumanya series. The bed consists of a marlstone layer that is less than 30 cm thick, and

Discussion

The analysis of the sedimentology, plant taphofacies and dinosaur track record in the ‘Grey Unit’ indicates that two distinct palaeoenvironments existed within the wetland area of Fumanya. These settings seem to be correlated with the two distinct distributions of track and plant remains. On one hand, track level I corresponds to a marginal brackish lagoon environment where no vegetation grew, and which features the accumulation of transported plant debris that represents the initial stage of

Conclusions

The study of the sedimentology, plant taphofacies and titanosaur ichnology at the Fumanya tracksites (early Maastrichtian, southern Pyrenees) reveals two distinct palaeoenvironments existing within the wetland areas, which are correlated with the occurrence of two distinct track and plant remains. These settings correspond to a marginal brackish lagoon environment where no vegetation grew and titanosaurs roamed without apparently any preferential purpose, and a freshwater lacustrine to

Acknowledgements

This paper is a contribution to projects CGL2011-30069-C02-01 and CGL2011-27869 of the Spanish Ministry of Economy and Competition. It also contributes to project SGR2009-1471 of the Catalan Autonomous Government. BV acknowledges support from the Spanish Ministry of Science and Innovation (Subprograma Juan de la Cierva (MICINN-JDC 2011)). We are grateful to two anonymous reviewers that provided useful comments to an early version of the manuscript and to Christopher Evans (Universitat de

References (37)

  • P. Dodson et al.

    Taphonomy and paleoecology of the dinosaur beds of the Jurassic Morrison Formation

    Paleobiology

    (1980)
  • F.T. Fürsich

    Palaeoecology and evolution of Mesozoic salinity-controlled benthic macroinvertebrate associations

    Lethaia

    (1994)
  • C.T. Gee

    Dietary options for the sauropod dinosaurs from an integrated botanical and paleobotanical perspective

  • J. Le Loeuff et al.

    Afloramiento de icnitas de Titanosauridae en la zona de Fumanya (Maastrichtiense, Pirineo oriental): estudio preliminar

    Geogaceta

    (1997)
  • T.M. Lehman

    The Alamo Wash local fauna: a new look at the old Ojo Alamo fauna

  • M.G. Lockley et al.

    The paleoenvironmental context, preservation and paleoecological significance of dinosaur tracksites in the Western USA

  • M.G. Lockley et al.

    The distribution of sauropod tracks and trackmakers

    GAIA

    (1994)
  • S.G. Lucas

    Dinosaur communities of the San Juan Basin: a case for lateral variations in the composition of Late Cretaceous dinosaur communities

  • Cited by (8)

    • Chronostratigraphic synthesis of the latest Cretaceous dinosaur turnover in south-western Europe

      2019, Earth-Science Reviews
      Citation Excerpt :

      Focusing on the turnover effect on the titanosaurians, Riera et al. (2009) and Riera (2010) proposed that the observed sauropod decline during the Maastrichtian was the consequence of a palaeoenvironmental bias. These studies considered that Ibero-Armorican titanosaurians preferred coastal environments (for instance, the Fumanya tidal flat; Vila et al., 2005; Marmi et al., 2014; Oms et al., 2016), so the apparent scarcity of such settings in the late Maastrichtion would explain the poor titanosaurian record after the turnover. However, a coastal habitat preference is not well supported for all titanosaurians in the region, because during the Campanian and the early Maastrichtian these sauropods were the dominant dinosaurs in fluvial deposits of Iberia and southern France (e.g. Le Loeuff et al., 1994; Garcia et al., 2010; Ortega et al., 2015).

    • A new narrow-gauge sauropod trackway from the Cenomanian Candeleros Formation, northern Patagonia, Argentina

      2019, Cretaceous Research
      Citation Excerpt :

      As was previously mentioned, the direction of the trackway is approximately parallel to the wave ripple-crest trend interpreted to be generated in a shallow body of water with temporary exposure within the floodplain. Physical barriers, like shoreline lakes, could condition the direction of sauropod walking (Lockley et al., 1986; Marmi et al., 2014). However, in the level bearing the Aguada de Tuco trackway no channel features were observed, and in the studied succession no significant physical barriers like large fluvial channels or lake deposits were recognized.

    • Geology and taphonomy of the L'Espinau dinosaur bonebed, a singular lagoonal site from the Maastrichtian of South-Central Pyrenees

      2017, Sedimentary Geology
      Citation Excerpt :

      The South-Pyrenean record has provided previous evidence of sauropod dinosaurs living near the sea. Examples include nesting in tidal flats and barrier islands (Sanz et al., 1995; López-Martínez et al., 2000) and roaming and foraging in brackish lagoons (Marmi et al., 2014; Oms et al., 2016). The hadrosauroid record has been documented in meandering channels from fluvial environments (Vila et al., 2013; Dalla Vecchia et al., 2014).

    • Transitional environments of the lower Maastrichtian South-Pyrenean Basin (Catalonia, Spain): The Fumanya Member tidal flat

      2016, Cretaceous Research
      Citation Excerpt :

      Further works on the Fumanya site have shown it to contain some 3500 titanosaurid footprints (Vila et al., 2008), dated at ca. 71.5 Ma (Oms et al., 2007). Despite the ichnological interest of the Fumanya site and other nearby outcrops (Vila, Oms, & Galobart, 2005, 2013), it has been the subject of other palaeontological research, including palaeobotany (Marmi, Gomez, Martín-Closas, & Villalba-Breva, 2010a, 2012b; Villalba-Breva, Martín-Closas, Marmi, Gomez, & Fernández-Marrón, 2012), vertebrate palaeontology (Marmi, Vila, & Galobart, 2009), palaeo-ecology (Marmi, Vila, Martín-Closas, & Villalba-Breva, 2014) and heritage (Bates et al., 2008). To date, the sedimentological study of the Fumanya Mb has been restricted to the Vallcebre syncline (Riera, Marmi, Oms, & Gomez, 2010) but here its study is expanded both laterally (basin scale) and vertically (older and younger adjacent strata) to understand how the regression of the South-Pyrenean basin around the Campanian–Maastrichtian boundary took place and led to the sedimentation of the Tremp Group.

    View all citing articles on Scopus
    View full text