Phosphatherium

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Phosphatherium
Pine fragment of phosphatherium

Pine fragment of phosphatherium

Temporal occurrence
Late Paleocene to early Eocene ( Thanetian to lowest Ypresian )
59.2 to 50.7 million years
Locations
Systematics
Higher mammals (Eutheria)
Afrotheria
Paenungulata
Tethytheria
Russell animals (Proboscidea)
Phosphatherium
Scientific name
Phosphatherium
Gheerbrant , Sudre & Cappetta , 1996
Art
  • Phosphatherium escuilliei

Phosphatherium is a genus of the proboscis and lived in the transition from the Paleocene to the Eocene between 59 and 53 million years ago in northern Africa . It is a small representative of the earliest proboscis animals and weighed a maximum of 15 kg. Most of the animals ate fruit . The design of the skull suggests that no trunk was formed.

features

Phosphatherium skull found in 1996

Phosphatherium was a small proboscis that may have weighed between 10 and 15 kg. The skull is best known, which has been handed down from numerous finds. This was 17 cm long with widely spreading cheekbones . The facial area in particular was very extensive, which was caused by the elongated nasal bone . The outer edges of the nostrils did not show any enlargement, as is the case with the later proboscis and indicate the point of attachment of the proboscis . The nasal bone also had no connection with the intermaxillary bone . Overall, the rostrum looked very narrow. A large infraorbital foramen opened above the second premolar . This is also where the infraorbital process began, indicating that the orbit was located relatively far forward in the skull. This is to be seen as a rather original characteristic of Tethytheria . The occiput had a rather rectangular shape and was very flat, the cerebral cavity showed lateral narrowing.

The lower jaw reached a length of 10 cm and had a rather low body. The number of teeth was somewhat reduced compared to older proboscis. Adult animals had the following tooth formula: The row of teeth extended over a length of 8 cm and did not even take up half the length of the skull. In the upper jaw, the second incisor (I2) was enlarged and conical in shape, but stood perpendicular in the bone. In the lower jaw, however, the first incisor (I1) showed significant enlargements. Both teeth, however, have not yet developed real tusks. The front teeth did not show a closed row of teeth, in the upper jaw there was an additional small diastema behind the first premolar. The premolars as a whole were quite simply built and little molarized, that is, they hardly resembled the molars . These had a bilophodontic structure with two clearly defined transverse melting strips . The rearmost molar of the lower jaw, however, had a third enamel bar. The teeth were generally low-crowned ( brachyodont ).

The few postcranial skeletal elements found so far include a few middle finger or toe bones with a length of 1.5 cm, which, however, allow only a few statements about the structure of the feet or hands.

Paleobiology

Live reconstruction of the head of Phosphatherium

Concerning the structure of the nose with the hardly elongated nostrils, it can be assumed that Phosphatherium did not develop a proboscis . The low-crowned molars with the clear enamel ridges speak for a preference for fruit-rich foods. Because the musculoskeletal system has largely not been handed down, hardly anything can be said about the mode of locomotion of the proboscis. It is therefore questionable whether Phosphatherium , like other early representatives of the Proboscidea, followed a semi-aquatic way of life. Due to the numerous remains of the skull, an intraspecific variation could be identified on the basis of differently developed muscle attachment points on the upper jaw, which is interpreted as sexual dimorphism .

Fossil finds

The first fossil finds were discovered in the northeastern part of the Ouled-Abdun Basin in a phosphate -containing layer. However, they only included two fragmented upper jaws. However, the exact location of this was not known. Further and much more extensive finds were discovered in the same basin in the Grand Daoui area in the early 2000s . This is made up of numerous skull fragments, the lower jaw and some skeletal elements of the musculoskeletal system. Other very early proboscis are known from the same area with the Eritherium or Daouitherium .

Systematics

Abbreviated internal systematics of the early proboscis according to Tabuce et al. 2019
  Proboscidea  

 Eritherium


   

 Phosphatherium


   

 Daouitherium


   

 Numidotherium


   


 Barytherium


   

 Omanitherium



   

 Arcanotherium


   

 Saloumia


   

 Moeritherium


   

 younger Proboscidea (Elephantiformes)


   

 Deinotheriidae



Template: Klade / Maintenance / 3







Template: Klade / Maintenance / Style

Phosphatherium is a genus of the order of Rüsseltiere (Proboscidea). The bilophodontic anterior molars and the vertical change of teeth, in which all teeth function simultaneously, refer them to the Plesielephantiformes, the most primal proboscis. However, the strong Lophodontie shows clear differences to the oldest Proboscidea like Eritherium , whose teeth are clearly bunodont. But also derived forms such as Arcanotherium and Moeritherium show clearly more bunodontic molars. The next possible relative is Daouitherium , which was also living in North Africa at the same time. Phosphatherium was originally ascribed to the Numidotheriidae family , and the extensive new find material from the Ouled-Abdun Basin led to the naming of the Phosphatheriidae family .

The first finds were probably made by a fossil dealer in the early 1990s from an unknown location. The two fragments of the upper jaw were coated with phosphate, and the preparation of the finds revealed the tooth of a fossil shark , which dates to the late Paleocene ( Thanetian ) and thus confirms the ancient age of the finds. The holotype (copy number MNHN PM2) consists of a right upper jaw part with the last two premolars and the first two molars (P3 to M2). It is now in the Muséum national d'histoire naturelle in Paris . The first scientific description was made in 1996 by Emmanuel Gheerbrant and research colleagues. The name Phosphatherium is made up of the Greek words φωςφορος ( phosphoros "light-bearing") and θηρίον ( thērion "animal") and refers to the fact that it is stored in phosphate- containing sediments. The only known species is Phosphatherium escuilliei . The species name escuilliei honors the person who found the first fossils, F. Escuillié. The first description was largely limited to the tooth features; a more extensive submission of the then known find material was only published two years later.

Individual evidence

  1. ^ A b Emmanuel Gheerbrant, Jean Sudre, Henri Cappetta and Gérard Bignot: Phosphatherium escuilliei du Thanétien du Bassin des Ouled Abdoun (Maroc), plus ancien proboscidien (Mammalia) d'Afrique. Geobios 30 (2), 1998, pp. 247-269
  2. a b c d e f Emmanuel Gheerbrant, Jean Sudre, Pascal Tassy, ​​Mbarek Amaghzaz, Baâdy Bouya and Mohamed Iarochène: Nouvelles données sur Phosphatherium escuilliei (Mammalia, Proboscidea) de l'Éocène inférieur du Maroc, ap des ongulés lophodontes. Geodiversitas 27 (2), 2005, pp. 239-333
  3. ^ A b c Emmanuel Gheerbrant, Jean Sudre and Henry Cappetta: A Palaeocene proboscidean from Morocco. Nature 383, 1996, pp. 68-70
  4. ^ Emmanuel Gheerbrant: The oldest known proboscidean and the role of Africa in the radiation of modern orders of placentals. Bulletin of the Geological Society of Denmark 44, 1998, pp. 181-185
  5. ^ A b Emmanuel Gheerbrant: Paleocene emergence of elephant relatives and the rapid radiation of African ungulates. PNAS 106 (26), 2009, pp. 10717-10721
  6. Emmanuel Gheerbrant, Jean Sudre, Henri Cappetta, Mohamed Iarochène, Mbarek Amaghzaz and Baâdi Bouya: A new large mammal from the Ypresian of Morocco: Evidence of surprising diversity of early proboscideans. Acta Palaeontologica Polonica. 47 (3), 2002, pp. 493-506
  7. Rodolphe Tabuce, Raphaël Sarr, Sylvain Adnet, Renaud Lebrun, Fabrice Lihoreau, Jeremy E. Martin, Bernard Sambou, Mustapha Thiam and Lionel Hautier: Filling a gap in the proboscidean fossil record: a new genus from the Lutetian of Senegal. Journal of Paleontology, 2019, doi: 10.1017 / jpa.2019.98