Eutatus

Skeletal reconstruction of Eutatus

• South America

Eutatus is an extinct genus of armadillos and is accurate also assigned to the fossil line of Eutatini, whose members were originally located in the southern part of South America. The genus lived mainly during the Pleistocene and reached the proportions of today's giant armadillo. It fed on According to research, mainly of plants and his hair was denser than in most of today's armadillos.

Features

Eutatus was a great representative of the Armadillos ( Dasypodidae ) and reached a head -body length of about 70 cm, assuming a body weight of about 50 kg. He had a size comparable to today's giant armadillo ( Priodontes maximus). In Build Eutatus resembled today's armadillos, but had some special features. The skull was up to 26 cm long and at the zygomatic arches 11 inches wide. The zygomatic shown in the side view also a downward-facing arc, so that they had a U- shaped curve. Above all, the rostrum was typically very elongated for eutatine armadillos, significantly more extensive than at its present relatives, such as the bristle armadillos ( Chaetophractus ). Furthermore, it was significantly higher than that of most members of the Eutatini. The approximately 15 cm long lower jaw had a slender build with low bone body. The dentition consisted of nine simple, nail -like teeth designed each half of the jaw, making a total of 36, with the posterior teeth were partially extended. In this case, no teeth were formed in the intermediate jaw bone.

A characteristic feature was the design of the tank. The head tank had a roughly triangular shape and consisted of Knochenschildchen whose surface was sculpted by more tubercle elevations. The oval and clearly had a stronger coupled carapace shoulder portion, which is typical for the Eutatini only to the front edges. The rest of the anterior and middle tank area consisted of a single, moving bands. The rigid rear pelvic part had a unique structure in that the individual bands were not running a semicircular shape on the tank, but in each case an open triangle with an obtuse angle at the center back shaped, its tip pointed ahead. On the surface showed the bone plates that formed the bands and were usually designed square, strong roughening by individual small holes and humps. They possessed a similar structure as in the other armadillos with an inner and outer layer of bone, between which individual cavities were, the glands and hair follicles showed. With four to six follicles per scutellum Eutatus had once been comparatively densely hairy.

Fossil finds

Eutatus occurred mainly during the Pleistocene in the central region of South America, but is also already in the late Pliocene around 3 million years ago demonstrated. Significant Fund points lie mainly in northern and central Argentina and southern Uruguay. Here are known more than 40 sites with fossil remains of armadillo species. A more or less complete individual is from Mar del Plata before in the Argentine province of Buenos Aires. From the same province comes a partial skeleton with skull and vertebrae and remains of the musculoskeletal system, which were discovered on the Río Salado. The recent finds are dated to the early Holocene.

Paleobiology

The construction of the mandible shows adaptations to a stronger, more plant-based diet. This is reflected, among other things, the joint ends that are designed rather flat and allow lateral chewing movements. Such food way could be found to show a rather Abrasionsmuster of herbivores also on the basis of microscopic examinations of the teeth. Similarly, the reconstruction of the masticatory muscles was found to be very strong and fit for plant food. Since Stenotatus, Doellotatus and Ringueletia have similar characteristics, such a diet seems to have been typical of eutatine armadillos. The significantly greater hairiness of Eutatus, recognizable by the larger number of hair follicles in the bone plate, maybe goes hand in hand with the cold and dry climate conditions of the Pampa region during the Pleistocene.

System

Eutatus is a now extinct genus of the family of armadillos ( Dasypodidae ) and belongs to the subfamily Euphractinae. This are the closest living relatives, the bristle armadillos ( Chaetophractus ), the six-banded armadillo ( Euphractus ) and the dwarf armadillo ( Zaedyus ). However, these three forms form a separate tribe within the Euphractinae that Euphractini while Eutatus is counted among the Eutatini, a now extinct line. The subfamily of Euphractinae joined fossil already in the Upper Eocene, about 40 million years, exhibit phylogenetic and anatomical point of view but the most advanced member of the armadillos dar. The Eutatini represent a potentially polyphyletic group, as with Proeutatus there is a form here which obviously is more closely related to the giant Glyptodontidae.

Today, a total of two types can be distinguished:

• E. Pascuali Krmpotic, Carlini & Scillato - Yane, 2009
• E. seguini Gervais, 1867

Further, usually established by Florentino Ameghino species such as E. brevis, E. punctatus and E. minutus are now placed to E. seguini. Here, this species is to E. Pascuali the younger and occurred mainly in the Middle Pleistocene and younger, while the latter existed since the late Pliocene and disappeared at the end of the Lower and Middle Pleistocene in the transition to. The first description of the genus was made in 1867 by Paul Gervais. The holotype ( specimen number MNHN - PAM: 273) includes a partial skeleton with skull and kept in the Natural History Museum in Paris.