Eomanis

Skeleton of Eomanis waldi

Germany ( Messel )

Eomanis is an extinct mammal of the family of Eomanidae and is one of the oldest undoubted relatives of pangolins ( Manidae ) is, of which up to now eight species in Africa and Asia live. It was a small, about half a meter long animal, which had typical adaptations to soil life and possibly docked burrows. In habit Eomanis exhibited typical on social insects as a food -referencing features. Discovered leftover food place so far but close to a plant-based diet. Fossil evidence comes only from the Messel Pit and dated to the Middle Eocene, 47 million years ago. The first description of the genus was made in 1978.

Features

Eomanis reached a head-body length of 25 to 27 cm, tail length was about 22 cm, which is about 88 % of the length of the rest of the body. In its general appearance it resembled today's pangolins ( Manidae ), but the body was a bit clumsy and the limbs shorter and stockier. The skull was 7.3 cm long and had long narrow shaped with a wedge-shaped in side view design. He possessed a flat skull roof. The very narrow pointed nose with a 2.9 cm length to around 40 % of the total length of the skull, while the frontal bone measured 1.9 cm. The zygomatic arches were not fully formed as in modern pangolins. The orbit had no demarcation to Temporalgrube, indicating that the eyes must have been very small. The lower jaw had a length of 5 cm, he was built elongated and shaped clasp. At the hinge end it reached a maximum of 1.2 cm in height. Due to lack of alveoli can be assumed that no teeth were formed, as is also now the case with the shed animals.

The body skeleton is widely known. So was the spine of 7 cervical, 12 thoracic, 5 lumbar, 4 sacral, and 24 caudal vertebrae. The cervical spine was short and the individual vertebrae were only low bone combs from the spinous processes. The lumbar spine was significantly penetrated with very short vertebrae, causing the hull appeared shortened significantly. The caudal vertebrae reported especially at the rear of no appendages and had overall a rather small and narrow shape. The humerus had a robust form, radius and ulna were not fused together. The Elle reached a length of 5 cm and had an extended upper joint ( olecranon ), which occupied only 1.6 cm of the total length of the bone. Also, the femur was vigorously shaped and measure up to 6 cm. The eye-catching third trochanter, a muscle attachment point, was far up the shaft of the bone near the top hinge. The bones of the lower leg portion were not fused as in the arms. The tibia was up to 5 cm long and had a columnar shaft, as well as the fibula, which was almost straight and was pretty slim. Arms and legs ended in each five-pointed hands and feet with short and wide phalanges. Here, especially the midstream (III ) was significantly prolonged. The fingers and toes ran out in sharp claws, but the respective end members were not split.

Today's pangolins have a characteristic scale pattern, which they also the trivial name " pine cone animals" owe due to the shingle of the individual scales. The scales are made of keratin, which is preserved fossil rare. A skeleton has aufgefundenes but in the area of the femur preserved shed residues and suggests that Eomanis had a similar armor. The scales were quite small and had with the pointed end towards the rear. The surface had a fine Längsriefelung, while the edge was bordered by a small shelves. Overall, the scales of Eomanis corresponded roughly to those of the present-day pangolins.

Fossil finds

The hitherto only known fossil remains of Eomanis are from the Messel Pit near Darmstadt. The entire reference is made in the Middle Eocene and thus has an age of 47 million years. Are known at least five nearly complete skeletons, including one of a young animal. It is noteworthy that the majority of the skeletons in the back, were rarely found in the prone position, which differs from the usual in Messel lateral position of the mammal finds ( with the exception of bats ). Reason for this may be the rather stocky physique, may still attended the training a vaulted shed tank, which was relatively difficult for most with the convex surface facing downward Einregelung in the quiet water environment of the former Maarsees.

Paleobiology

Overall Eomanis had a strong physique with short limbs and remembered today pangolins, but has a comparatively shorter and somewhat clumsier fuselage and a larger skull, eventually related to a less specialized lifestyle. In particular, the front legs were characterized by a short and wide humerus, which offered plenty of space for muscle attachment sites. The very extensive upper joint ( olecranon ) of the ulna is comparable, suggesting a similar lifestyle to the burrowing mammals living in today as the recent dandruff but also the armadillos. This is also reflected the extended middle finger and the broad phalanges. Probably lived Eomanis as scratching digger who looked for food and underground shelters docked against predators. The relatively thin tail can but assume that this did not act as a support while digging, climbing or upright, as is the case with pangolins or analog in anteaters and armadillos. For this reason Eomanis probably lived as pure soil animal and moves there plantigrade continued. Also show the hind legs some special features. Thus, the third trochanter is clearly added at Eomanis towards the upper hinge end and not as with most specialized graves to the center on the bone shaft. Thus, the hind limbs were less stretchable and not very suitable for grave work, they were therefore probably not for pushing away the excavation. The cervical spine was very short and broad and the head thus less mobile.

Despite individual anatomical differences Eomanis as of today pangolins appear in his habit strongly to have been adapted to a way of life. This feed mainly on social insects such as ants and termites ( Myrmecophagie ). That obviously was a Eomanis already fully developed Myrmecophage, moreover, certain features of the skull. These include the prolonged, partly tubular snout, loss of teeth and the clasp-like, narrow expression of the mandible, but also the only small muscle attachment areas, indicating a reduced masticatory muscles. Such features evolved several times independently, and come not only with the prior pangolins, but also with the anteaters. Food intake is done in both groups over a long flexible and sticky tongue which can be assumed Due to the skull construction even in Eomanis. In contrast to these clearly myrmecophagen adjustments but are among some of the Messel skeletal remains discovered remains of food in the gastrointestinal area. There are the remains of sand grains that do not occur in the Maarseeablagerungen of Messel to one portion. Sand is also taken from today's pangolins and serves to break up the swallowed chewing because of missing teeth food. In addition, however only few remains of insects are detected, especially the Chitinhüllen. Anyway, to get large amounts of plant material such as leaf debris with a well preserved cellular tissue and herb stems. Was a angedachte possibility that a large part of the insect remains had been degraded by formic acid in the stomach space - Today representatives of the shed ants have up to 70 % formic acid as a defense secretion - which, however, the plant remains undecomposed, which in experiments could not be confirmed. On the other hand, it was believed that it is only apparent food debris that had accumulated secondarily in the abdominal area of the animals in the supine and in these slumped after the decomposition of the soft tissue inside. But even here there are some taphonomic problems, as would then need to store and not as decayed detritus, which would likely have been the case, among others, the plant remains in the various Eomanis skeletons in a freshly crushed state. For this reason, the editor of the findings assumed that the food of Eomanis from finely chopped plant parts of leaf-cutting ants was, with the energy-rich insects as " bycatch " were included, and within the precursor of pangolins later an adjustment on ants and termites took shape. However, this model does not explain the eineutig myrmecophage feature training at Eomanis. Therefore, other scientists see in Eomanis a fully developed insectivore that choking plants only random, with the insect remains are not or only barely survived for unknown reasons. So far, the dominance of the plant material in the food debris is not released.

System

Euromanis

Eurotamandua

Eomanis

Necromanis

Patriomanidae

Manidae

Palaeanodonta

Eomanis is a genus of the family of Eomanidae, which in turn belongs to the order Pholidota be assigned as the sole extant family of the extant pangolins ( Manidae ). Together with the extinct Palaeanodonta, which are restricted to the Paleogene of North America and Europe, they form the superorder Pholidotamorpha. Originally, Eomanis as extinct member of today's pangolins and as its oldest undoubted representative, but it was later spun off into the related Patriomanidae, which included representatives of all fossil pangolins. It was not until in 2003 due to the resulting paraphyletic origin of Patriomanidae an assignment to the family Eomanidae.

At the close relatives of Eomanis include Euromanis and Eurotamandua, both of which are also handed down from the Messel Pit. The two genera together with Eomanis are at the basis of the development of Pholidota and still have a number of original features that they have in common with the Palaeanodonta and from which they may be developed. These include a C-shaped jaw means designed, a small bone ridge at the rear end of the jaw and some special characteristics of the front legs, such as the extending end members of the front legs. For a long time there was a systematic controversy whether Eurotamandua stands with Eomanis in relationship, since the former was originally identified as a representative of anteaters - it would therefore be the only European representative of this otherwise known only from South America animal group and the oldest ever. This controversy was also due to the fact that pangolins and anteaters have great similarities in physique and have long been held related to each other for near. Could be determined by recent molecular genetic studies have shown that this similarity is based solely on convergence.

It is known a way Eomanis waldi, which was first described by Gerhard Storch in 1978. The holotype ( specimen number SMF Me 84) is a complete skeleton that is on the back. It is privately owned by the Finders, a cast is in the Senckenberg Research Institute in Frankfurt am Main before. The genus name Eomanis refers to the age of the finds ( Eocene ) and the relationship with the pangolin ( Manis the genus within the Manidae ). The species name honors the waldi Finder Rudolf forest, which represented the Fund for research purposes. Another way Eomanis krebsi, also introduced in 1994, von Storch, is regarded today as a representative of the genus Euromanis, which received its first description in 2009.

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