La Colonia Formation

Campanian to Maastrichtian

Provincia de Chabut, Argentina

Dinosaurs:

Theropoda indet.

Carnotaurus sastrei

            Titanosauria indet.

Ankylosauria indet.

Hadrosauroidea indet.

Other Animals:

            Elasmosauridae indet.

            Sulcusuchus erraini

            Meiolaniidae indet.

            Patagoniaemys gasparinae

            Chelidae indet.

Yaminuechelys gasparinii

Serpentes indet.

Madtsoiidae indet.

Alamitophis argentines

Boidae indet.

Enantiornithes indet.

Argentodites coloniensis

Coloniatherium cilinskii

Reigitherium bunodontum

Plants:

Azolla sp.

Crybelosporites pannuceus

Cyathidites australis

Dicksonia sp.

Gleicheniidites senonicus

Lugiomarsiglia aquatica

Mirasolita irupensis

Molaspora lobata

Paleoazolla patagonica

Regnellidium thomas-taylorii

Classopollis sp. 1

Classopollis sp. 2

Cheirolepidiaceae indet.

Lygistepollenites sp.

Microchacrydites sp.

Podocarpidites spp.

Arecipites spp.

Dicotyledoneae indet.

Inaperturotetradites sp.

Intratriporopollenites sp.

Araceae indet.

Arecaceae indet.

Nelumbo puertae

Pandaniidites sp.

Peninsulapollis sp.

Nelumbonaceae indet.

Sparganiaceaepollenites sp.

Typha sp.

Typhaceae indet.

Botryococcus sp.

Botryococcus braunii

Pediastrum sp. 1

Pediastrum sp. 2

Pediastrum boryanum

Mougeotia sp.

Spirogira sp. 1

Spirogira sp. 2

Zygnema sp.

Fungi indet.

Notes:

Despite the 1980s discovery of the horned theropod Carnotaurus in the formation, nothing has been published on other dinosaur remains from the formation. However, some fantastic research has detailed the plant life of the formation, providing a fairly accurate picture of the environment. It was a swamp, possibly near the mouth of a river, emptying into a larger body of water. It is a good possibility that it was part of a seacoast at the time, before flooding or a landslide of some kind apparently buried both terrestrial and aquatic inhabitants. Besides dinosaurs on land, snakes, particularly boids and their relatives, like Alamitophis, were common. They preyed on a variety of small mammals, including multituberculates and dryolestids. The most common were Coloniatherium, a rat-like dryolestid. The water was full of turtles, including relatives of the modern mata mata and the amazingly horny meiolaniid Patagoniaemys. Commonly plying through the deeper water were elasmosaurs, classic, long-necked plesiosaurs. Sulcusuchus was also a large mobile plesiosaur, but of a short-necked, long-snouted kind. The plant life of the La Colonia is a fascinating subject. Cúneo et al. (2014) is a great read and details the genera and kinds of plants that dominated, from open water to shoreline into the forest. It seems that floating plants like Azolla and water lettuce were dense in calm water while lotus and aquatic ferns grew in shallow water and cattails lined the shore. Tree ferns and palms dominated the forest.

References:

Cúneo, N. R., M. A. Gandolfo, M. C. Zamaloa, et E. Hermsen. 2014. “Late Cretaceous aquatic plant world in Patagonia, Argentina.” PLoS ONE 9(8): e104749