Phosphatherium

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Phosphatherium
Temporal range: Late Paleocene to Ypresian
Phosphatherium escuilliei.JPG
Fossil
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Proboscidea
Family: Numidotheriidae
Genus: Phosphatherium
Gheerbrant, Sudre & Cappetta, 1996 [1]
Species:
P. escuillei
Binomial name
Phosphatherium escuillei
Gheerbrant, Sudre & Cappetta, 1996 [1]

Phosphatherium escuillei is a basal proboscidean that lived from the Late Paleocene (early Thanetian some 59 Ma) to the early stages of the Ypresian age [2] . Research has suggested that Phosphatherium existed during the Eocene period. [3]

Contents

Description

Restoration Phosphatherium - head restoration.tif
Restoration

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. [4] The sagittal crest, 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. [4] [5]

Skull Phosphatherium, discovered in 1996 Phosphatherium skull 1996.jpg
Skull Phosphatherium, discovered in 1996

One of the main factors of Phosphatherium's 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's face by a varying degrees of muscle attachments on its upper jaw. [6]

Phosphatherium lacked a trunk. The tooth rows extend back to roughly 45% of its total skull length. The dental structures suggests that P. escuillei is a heterodont, meaning it possessed more than one type of tooth morphology. [7] 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. [8]

The unique traits of Phosphatherium teeth suggest them to be intraspecific. Some features of P. escuilliei's teeth and jaw structures also show noticeable variation, which is related to sexual dimorphism. This suggests physiological differences existed between males and females, which ultimately suggest behavioral differences. [9]

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 proboscideans. Adult animals had the following dental formula:

Dentition
3.1.4.3
2.1.3.3

The tooth row extended over a length of 8 cm, taking up less than half of the skull length. In the upper jaw, the second incisor (I2) was enlarged and conical in shape, but was perpendicular to the bone. In the lower jaw, on the other hand, the first incisor (I1) showed clear enlargements. However, both teeth did not yet form true tusks. The anterior dentition 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 not very molarised, i.e. they hardly resembled the molar. These had a bilophodont structure with two clearly formed transverse enamel ridges. The rearmost molar of the mandible, however, had a third enamel bar. In general, the teeth were brachyodont. [1] [9]

Discovery

Map showing where fossils have been found Phosphatherium escuilliei distribution.svg
Map showing where fossils have been found

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. [1]

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. [9] [10] Other very early proboscideans are known from the same area, the related Eritherium and Daouitherium . [11]

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 [12] and smallest members of the Proboscidea, with an estimated shoulder height of about 30 centimetres (12 in) and body mass of 17 kilograms (37 lb). [13] 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. [14]

  Proboscidea  

  Eritherium

 Phosphatherium

  Daouitherium

  Numidotherium

  Barytherium

  Omanitherium

  Arcanotherium

  Saloumia

  Moeritherium

 Derived Proboscidea (Elephantiformes)

  Deinotheriidae

Palaeobiology

Jaw fragments Phosphatherium escuilliei 65.JPG
Jaw fragments

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. [15]

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. [10]

Related Research Articles

<span class="mw-page-title-main">Proboscidea</span> Order of elephant-like mammals

Proboscidea is 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. Proboscideans include some of the largest known land mammals. The largest land mammal of all time may have been a proboscidean; the elephant Palaeoloxodon namadicus has been estimated to be up to 5.2 m (17.1 ft) at the shoulder and may have weighed up to 22 t, surpassing the paraceratheres, the otherwise largest known land mammals, though this estimate was made based on a single fragmentary femur and is speculative. The largest extant proboscidean is the African bush elephant, with a record of size of 4 m (13.1 ft) at the shoulder and 10.4 t. In addition to their enormous size, later proboscideans are distinguished by tusks and long, muscular trunks, which were less developed or absent in early proboscideans.

<span class="mw-page-title-main">Desmostylia</span> Extinct order of mammals

The Desmostylia are an extinct order of aquatic mammals native to the North Pacific from the early Oligocene (Rupelian) to the late Miocene (Tortonian). Desmostylians are the only known extinct order of marine mammals.

<i>Anancus</i> Genus of proboscideans

Anancus is an extinct genus of "tetralophodont gomphothere" native to Afro-Eurasia, that lived from the Tortonian stage of the late Miocene until its extinction during the Early Pleistocene, roughly from 8.5–2 million years ago.

Numidotheriidae is an extinct family of primitive proboscideans that lived from the late Paleocene to the early Oligocene periods of North Africa.

<i>Daouitherium</i> Extinct genus of mammals

Daouitherium is an extinct genus of early proboscideans that lived during the early Eocene some 55 million years ago in North Africa.

<i>Numidotherium</i> Genus of mammals

Numidotherium is an extinct genus of early proboscideans, discovered in 1984, that lived during the middle Eocene of North Africa some 46 million years ago. It was about 90-100 cm tall at the shoulder and weighed about 250-300 kg.

<i>Chenanisuchus</i> Extinct genus of reptiles

Chenanisuchus is a genus of dyrosaurid crocodyliform from the Late Cretaceous of Mali and the Late Palaeocene of Sidi Chenane in Morocco. It was described in 2005, after expeditions uncovered it in 2000.

<span class="mw-page-title-main">Dyrosauridae</span> Extinct family of reptiles

Dyrosauridae is a family of extinct neosuchian crocodyliforms that lived from the Campanian to the Eocene. Dyrosaurid fossils are globally distributed, having been found in Africa, Asia, Europe, North America and South America. Over a dozen species are currently known, varying greatly in overall size and cranial shape. A majority were aquatic, some terrestrial and others fully marine, with species inhabiting both freshwater and marine environments. Ocean-dwelling dyrosaurids were among the few marine reptiles to survive the Cretaceous–Paleogene extinction event.

<i>Arambourgisuchus</i> Extinct genus of reptiles

Arambourgisuchus is an extinct genus of dyrosaurid crocodylomorph from the late Palaeocene of Morocco, found in the region of Sidi Chenane in 2000, following collaboration by French and Moroccan institutions, and described in 2005 by a team led by palaeontologist Stéphane Jouve. Arambourgisuchus was a large animal with an elongated skull 1 meter in length.

Argochampsa is an extinct genus of eusuchian crocodylomorph, usually regarded as a gavialoid crocodilian, related to modern gharials. It lived in the Paleocene of Morocco. Described by Hua and Jouve in 2004, the type species is A. krebsi, with the species named for Bernard Krebs. Argochampsa had a long narrow snout, and appears to have been marine in habits.

<i>Notiomastodon</i> Extinct genus of mammals

Notiomastodon is an extinct genus of gomphothere proboscidean, endemic to South America from the Pleistocene to the beginning of the Holocene. Notiomastodon specimens reached a size similar to that of the modern Asian elephant. Like other brevirostrine gomphotheres such as Cuvieronius and Stegomastodon, Notiomastodon had a shortened lower jaw and lacked lower tusks.

<i>Eritherium</i> Genus of mammals

Eritherium is an extinct genus of early Proboscidea found in the Ouled Abdoun basin, Morocco. It lived about 60 million years ago. It was first named by Emmanuel Gheerbrant in 2009 and the type species is Eritherium azzouzorum. Eritherium is the oldest, smallest and most primitive known elephant relative.

<i>Ocepeia</i> Extinct Afrotherian mammal

Ocepeia is an extinct genus of afrotherian mammal that lived in present-day Morocco during the middle Paleocene epoch, approximately 60 million years ago. First named and described in 2001, the type species is O. daouiensis from the Selandian stage of Morocco's Ouled Abdoun Basin. A second, larger species, O. grandis, is known from the Thanetian, a slightly younger stage in the same area. In life, the two species are estimated to have weighed about 3.5 kg (7.7 lb) and 10 kg (22 lb), respectively, and are believed to have been specialized leaf-eaters. The fossil skulls of Ocepeia are the oldest known afrotherian skulls, and the best-known of any Paleocene mammal in Africa.

<span class="mw-page-title-main">Ouled Abdoun Basin</span> Phosphate basin in Morocco

The Oulad Abdoun Basin is a phosphate sedimentary basin located in Morocco, near the city of Khouribga. It is the largest in Morocco, comprising 44% of Morocco's phosphate reserves, and at least 26.8 billion tons of phosphate. It is also known as an important site for vertebrate fossils, with deposits ranging from the Late Cretaceous (Cenomanian-Turonian) to the Eocene epoch (Ypresian), a period of about 25 million years.

<i>Abdounodus</i> Extinct genus of mammal

Abdounodus is an extinct genus of mammal known from the middle Paleocene of northern Africa. The sole species, A. hamdii, is known from teeth discovered in the Ouled Abdoun Basin of present-day Morocco in 2001. Traditionally considered a mioclaenid "condylarth", recent studies place it as a basal afrothere closely related to Ocepeia, demonstrating the close convergent evolution between perissodactyls and herbivorous afrotheres and bridging paenungulates with other afrotheres.

Saloumia is an extinct genus of the order Proboscidea. It is one of the oldest members of the order and lived in the middle Eocene of Senegal. It is known only from a single molar, whose pronounced bumpy chewing surface indicates it is probably closely related to Moeritherium.

Dagbatitherium is an extinct genus of proboscideans. So far a single molar from the phosphate basins of Togo in West Africa has been found. The fossil dates to the Middle Eocene, around 47 million years ago. A striking feature of the tooth are the three pairs of cusps oriented transversely to the longitudinal axis of the tooth. This feature is found in more derived proboscideans, which are grouped in the Elephantiformes. For its age, Dagbatitherium is the earliest member of Elephantiformes to date. Furthermore, it is characterized by a low tooth crown and a humped occlusal pattern. The genus was described in 2021.

<i>Thalassotitan</i> Large bodied African mosasaur

Thalassotitan is an extinct genus of large mosasaurs that lived during the late Maastrichtian of the Cretaceous period in what is now Morocco, around 66 million years ago. The only known species is T. atrox, described in 2022 from fossils discovered in the Ouled Abdoun Basin, where many other mosasaurs have been found. It was assigned to the tribe Prognathodontini alongside other mosasaurs like Prognathodon and Gnathomortis. The prognathodontines are separated from other mosasaurs based on their massive jaws and robust teeth.

Hadrogeneios is an extinct genus of afrotherian mammal recovered from the Khouribga Phosphates of the Ouled Abdoun Basin dating from the Selandian to the Thanetian. Only the type species H. phosphaticus is known for this genus, with the material being of dental and jaw specimens. The placement of Hadrogeneios recovered it to be the most basal stem-paenungulate, the clade that includes elephants, sea cows, and hyraxes. Despite this Hadrogeneios was a contemporary of more derived members of the group such as Abdounodus, Ocepeia, and the early proboscideans Eritherium, Phosphatherium, and Daouitherium.

Grand Daoui is a quarry in the Ouled Abdoun Basin of Morocco known for its fossils. It is the discovery place of Phosphatherium escuilliei, the earliest known proboscidean. It was the location for several field parties between 1997 and 2001, which allowed survey of the geological and paleontological context of Phosphatherium localities. It is also rich in marine vertebrae fossils. All Phosphatherium remains to date have been found in the quarry. The discovery of fossils there has aided in the study of early African placental fauna. The marine snake Palaeophis maghrebianus is also known from the locality, as well as the primitive gavialoid Argochampsa krebsi.

References

  1. 1 2 3 4 Gheerbrant, E.; Sudre, J.; Cappetta, H. (1996). "A Palaeocene proboscidean from Morocco". Nature . 383 (6595): 68–71. Bibcode:1996Natur.383...68G. doi:10.1038/383068a0. S2CID   4362199.
  2. http://www3.planetarioroma.it/content/download/4908/62991/file/637_638.pdf. Archived 2016-03-05 at the Wayback Machine
  3. Seiffert, Erik R. (2007). "A new estimate of afrotherian phylogeny based on simultaneous analysis of genomic, morphological, and fossil evidence". BMC Evolutionary Biology. 7 (1): 224. Bibcode:2007BMCEE...7..224S. doi: 10.1186/1471-2148-7-224 . PMC   2248600 . PMID   17999766.
  4. 1 2 Gheerbrant, E; Amaghzaz, M; Bouya, B; Goussard, F; Letenneur, C (2014). "Ocepeia (Middle Paleocene of Morocco): the oldest skull of an afrotherian mammal". PLOS ONE. 9 (2): e89739. Bibcode:2014PLoSO...989739G. doi: 10.1371/journal.pone.0089739 . PMC   3935939 . PMID   24587000.
  5. Ferretti, Marco; Debruyne, Regis (2010). "Anatomy and Phylogenetic Value of the Mandibular and Coronoid Canals and Their Associated Foramina in Proboscideans (Mammalia)". Zoological Journal of the Linnean Society. 161 (2): 391–413. doi: 10.1111/j.1096-3642.2010.00637.x .
  6. Gheerbrant, Emmanuel; Sudre, Jean; Tassy, Pascal; Amaghzaz, Mbarek; Bouya, Baâdy; Iarochène, Mohamed (2005). "Nouvelles données sur Phosphatherium escuilliei (Mammalia, Proboscidea) de l'Eocene inférieur du Maroc, apports à la phylogeny of the Proboscidea et the ongulés lophodontes". Geodiversitas. 27 (2): 239–333.
  7. https://www.app.pan.pl/archive/published/app47/app47-493.pdf [ bare URL PDF ]
  8. "Archived copy" (PDF). Archived from the original (PDF) on 2014-10-24. Retrieved 2014-10-23.{{cite web}}: CS1 maint: archived copy as title (link)
  9. 1 2 3 Gheerbrant, E. ( 1 ), et al. "New Data On Phosphatherium Escuilliei (Mammalia, Proboscidea) From The Early Eocene Of Morocco, And Its Impact On The Phylogeny Of Proboscidea And Lophodont Ungulates." Geodiversitas 27.2 (2005): 239-333.
  10. 1 2 Gheerbrant, Emmanuel (1998). "The Oldest Known Proboscidean and the Role of Africa in the Radiation of Modem Orders of Placentals". Bulletin of the Geological Society of Denmark. 44: 181–85. doi: 10.37570/bgsd-1998-44-12 .
  11. Gheerbrant, E.; Sudre, J.; Cappetta, H.; Iarochène, M.; Amaghzaz, M.; Bouya, B. (2002). "A new large mammal from the Ypresian of Morocco: Evidence of surprising diversity of early proboscideans" (PDF). Acta Palaeontologica Polonica. 47 (3): 493–506.
  12. Gheerbrant, Emmanuel; Sudre, Jean; Cappetta, Henri; Mourer-Chauviré, Cécile; Bourdon, Estelle; Iarochene, Mohamed; Amaghzaz, Mbarek; Bouya, Baâdi (2003). "The mammal localities of Grand Daoui Quarries, Ouled Abdoun Basin, Morocco, Ypresian : A first survey" (PDF). Bulletin de la Société Géologique de France. 174 (3): 279–293. doi:10.2113/174.3.279.
  13. Larramendi, A. (2016). "Shoulder height, body mass and shape of proboscideans" (PDF). Acta Palaeontologica Polonica. 61. doi: 10.4202/app.00136.2014 .
  14. Rodolphe Tabuce, Raphaël Sarr, Sylvain Adnet, Renaud Lebrun, Fabrice Lihoreau, Jeremy E. Martin, Bernard Sambou, Mustapha Thiam and Lionel Hautier; 2019 "Filling a gap in the proboscidean fossil record: a new genus from the Lutetian of Senegal." Journal of Paleontology. doi:10.1017/jpa.2019.98
  15. Calandra, Ivan; Göhlich, Ursula B.; Merceron, Gildas (2010). "Feeding preferences of Gomphotherium subtapiroideum (Proboscidea, Mammalia) from the Miocene of Sandelzhausen (Northern Alpine Foreland Basin, southern Germany) through life and geological time: evidence from dental microwear analysis". Paläontologische Zeitschrift. 84 (1): 205–215. Bibcode:2010PalZ...84..205C. doi:10.1007/s12542-010-0054-0. S2CID   56260944.

Further reading