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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 part of the jaw 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 took place in 1996 by Emmanuel Gheerbrant and 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 type fossils, François Escuillié. The first description was largely limited to the tooth features, a more extensive template of the then known find material was only published two years later.
The first fossil finds were discovered in the north-eastern part of the Ouled Abdoun Basin in a phosphate-containing layer. However, they only comprised two fragmented upper jaws. However, the exact location of this find was not known. Further and much more extensive finds were discovered in the early 2000s in the same basin in the ''Grand Daoui'' area. This consists of numerous skull fragments, mandibles and some limb elements.Eritherium
''Eritherium'' is an extinct genus of early Proboscidea found in the Ouled Abdoun basin (early Thanetian age), Morocco. It lived about 60 million years ago. It was first named by Emmanuel Gheerbrant in 2009 and the type species is ''Eritherium ...
'' and '' Daouitherium''.
''Phosphatherium escuillei'' is a basal proboscidean that lived from the Late Paleocene to the early stages of the Ypresian age until the early Thanetian some 56 million years ago in North Africa. Research has suggested that ''Phosphatherium'' existed during the Eocene period.
One of the main factors of ''Phosphatherium'' body is its nontraditional musculoskeletal system. The shape of its head is composed of attributes of a snout, more vividly, turning into
a mouth with a rounded jawline. Similar mammals in its order retained a more snout-like nose, which was also a factor that pertained to it having a semiaquatic lifestyle. Furthermore, sexual dimorphism can be noticed on ''Phosphatherium'' face by a varying degrees of muscle attachments on its upper jaw.heterodont
In anatomy, a heterodont (from Greek, meaning 'different teeth') is an animal which possesses more than a single tooth morphology.
In vertebrates, heterodont pertains to animals where teeth are differentiated into different forms. For example, ...
, meaning it possessed more than one type of tooth morphology. This is evident because they possessed more than one type of molar upon fossil examinations. The various dental formations of heterodonts suggest that this animal, unlike later proboscideans, may have been omnivorous.
The unique traits of ''Phosphatherium'' teeth suggest them to be intraspecific. Some features of ''P. escuilliei''Description
''P. escuillei'' possessed rather flat features, centered around a low skull and a long, straight dorsal profile. The skull itself was rather disproportionate, consisting of an elongated cranial region and a rather short rostrum. Thesagittal crest
A sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull (at the sagittal suture) of many mammalian and reptilian skulls, among others. The presence of this ridge of bone indicates that there are exceptiona ...
, the ridge along the dorsomedian line of its skull, spans across nearly half of the skull itself. The nasal cavity is high and wide, suggesting a large snout in life.
One of the main factors of ''Phosphatherium'' body is its nontraditional musculoskeletal system. The shape of its head is composed of attributes of a snout, more vividly, turning into
a mouth with a rounded jawline. Similar mammals in its order retained a more snout-like nose, which was also a factor that pertained to it having a semiaquatic lifestyle. Furthermore, sexual dimorphism can be noticed on ''Phosphatherium'' face by a varying degrees of muscle attachments on its upper jaw.heterodont
In anatomy, a heterodont (from Greek, meaning 'different teeth') is an animal which possesses more than a single tooth morphology.
In vertebrates, heterodont pertains to animals where teeth are differentiated into different forms. For example, ...Discovery
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 part of the jaw 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 took place in 1996 by Emmanuel Gheerbrant and 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 type fossils, François Escuillié. The first description was largely limited to the tooth features, a more extensive template of the then known find material was only published two years later.
The first fossil finds were discovered in the north-eastern part of the Ouled Abdoun Basin in a phosphate-containing layer. However, they only comprised two fragmented upper jaws. However, the exact location of this find was not known. Further and much more extensive finds were discovered in the early 2000s in the same basin in the ''Grand Daoui'' area. This consists of numerous skull fragments, mandibles and some limb elements.Eritherium
''Eritherium'' is an extinct genus of early Proboscidea found in the Ouled Abdoun basin (early Thanetian age), Morocco. It lived about 60 million years ago. It was first named by Emmanuel Gheerbrant in 2009 and the type species is ''Eritherium ...Taxonomy
''Phosphatherium'' is known primarily from two maxilla fragments dated to the latest Paleocene deposits of the Ouled Abdoun Basin, Morocco, which date from the Thanetian epoch. It is one of the oldest and smallest members of theProboscidea
The Proboscidea (; , ) are a taxonomic order of afrotherian mammals containing one living family (Elephantidae) and several extinct families. First described by J. Illiger in 1811, it encompasses the elephants and their close relatives. From ...
, with an estimated shoulder height of about and body mass of . Like its later relative, '' Moeritherium'', the animal was probably an amphibious browser that fed on aquatic plants, akin to a very small tapir. Both animals are included in the family Numidotheriidae, together with '' Numidotherium''.
Below is a phylogenetic tree based on Tabuce ''et al''. 2019.Palaeobiology
''Phosphatherium'' is thought to have had a broad diet. The dental microwear patterns observed on their teeth show lengthy scratches on the molars of juveniles. Correspondingly, similar patterns are found on adult individuals. Through study of the wear and specifically scratches on the teeth of ''Phosphatherium'', the food items it ingested include shrubs and bushes, indicating a mixed feeding preference. Adult molars are found to have a much higher density of scratches, indicating abrasive food sources and possibly insects and small animals. Overall, ''Phosphatherium'' is thought to be an omnivorous browser mainly determined by its preferences, as well as the availability of resources.
Considering its highly adapted folivorous jaw and tooth structure, ''Phosphatherium'' provides evidence of the high age of African endemism. The dental structure of ''Phosphatherium'' suggests its diet consisted mainly of leaves, which indicates it may have fulfilled a niche role in its environment, although diet can only be inferred. The discovery of this animal has ultimately helped reinforce the African origin of proboscideans, and provide insight into the radiation of modern orders of placental mammals.
References
* http://mygeologypage.ucdavis.edu/cowen/historyoflife/Phosphatherium.html {{Taxonbar, from=Q134951 Paleocene proboscideans Eocene proboscideans Ypresian extinctions Transitional fossils Paleocene mammals of Africa Eocene mammals of Africa Prehistoric placental genera Prehistoric monotypic mammal genera Fossil taxa described in 1996