Patriomanis
| Patriomanis | ||||||||||||
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| Temporal occurrence | ||||||||||||
| Upper Eocene | ||||||||||||
| 36.2 to 33.9 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Patriomanis | ||||||||||||
| Emry , 1970 | ||||||||||||
Patriomanis is an extinct genus of pangolins . It is referred to the family of Patriomanidae , which in turn is closely related to the Manidae, the family of recent forms. The animals reached the size of the Chinese or Malay pangolin , but were characterized by more robust limbs and less powerful hands and feet. The tail could be used as a grasping tail and thus suggests not only a digging way of life but also climbing in trees. The finds from Patriomanis include several individual skeletons, which means that almost the entire skeletal anatomical structure of the animals can be reconstructed. Most of them come from Wyoming and date to the Upper Eocene between 34 and 36 million years ago. It is the only known representative of the pangolins from North America .
features
Patriomanis is one of the best and most complete surviving representatives of the extinct pangolin. In terms of its size, it was roughly equivalent to the Chinese pangolin ( Manis pentadactyla ) or the Malay pangolin ( Manis javanica ). In terms of skull construction, too, it was similar to today's forms. A complete skull measured 9.2 cm in length. As with the more recent species, there were no conspicuous bone marks as muscle attachment points. The rostrum had a typical tubular shape, the entire fore-eye section was clearly drawn out. In proportion, Patriomanis was more like the Malay pangolin than the Chinese pangolin, which has a relatively shorter snout. The upper jaw was noticeably high, the connection to the middle jawbone pointed backwards in accordance with the Malay and different from the Chinese pangolin. Both bones had no alveoli , so that the skull was toothless, analogous to today's pangolins. The nasal bone is incomplete, but the front end was pointed. The zygomatic arch was poorly developed and, like most pangolins of today, not closed. The parietal bones were straight along, but were strongly curved towards the side of the skull. On the occiput , near the lambda suture, there was a slight bone bulge that is absent in recent species. The articular surfaces for the connection with the cervical spine pointed backwards. At the base of the skull there was no glenoid pit on the temporal bone for anchoring the lower jaw. The lower jaw itself had a clasp-shaped shape, the longest surviving specimen measures 6.7 cm. Here, too, as is typical for pangolins, the alveoli for the teeth were missing, the upper edge of the horizontal bone formed a sharp ridge. The symphysis was long and had a smooth profile underneath. At the rear end there was a canine-like bone tip , which is also found in pangolins today, but is a little further back. In front of and behind the base of the tip of the bone there was a mental foramen , with the more recent representatives the rear one is located directly below the tip of the bone. In contrast to today's pangolins, the lower jaw of Patriomanis still had a short crown and an angular process.
The spine consisted of 7 cervical, an estimated 15 thoracic, 7 lumbar, 3 sacrum and about 36 caudal vertebrae. The spinous processes of the thoracic vertebrae had a relatively uniform height, which roughly corresponds to the situation in today's species. They pointed backwards in the anterior vertebrae and upwards in the posterior vertebrae. The latter continued in the lumbar vertebrae. The caudal spine was significantly larger than that of the closely related Cryptomanis and more comparable to that of today's white-bellied pangolin ( Phataginus tricuspis ). On the sides of the vertebrae, massive transverse processes began, which had forked ends towards the middle tail section. There were also articular surfaces for attaching chevron bones on the underside .
The musculoskeletal system is almost completely occupied. The humerus was 7.7 cm long. The head was clearly arched and separated from the large protruding bone (tuberculum majus) by a depression. This protruding bone merged into a massive deltopectoral groin, which ran along the shaft of the humerus and was folded over roughly in the middle, this is where the biceps started . It ended somewhat abruptly in a groove above the elbow joint where the biceps tendon ended. The lower end of the joint was strongly protruding to the side. The ulna reached a length of 6.7 cm and was thus about 88% of the length of the humerus. The olecranon took up about 1.8 cm of this total length , which is more than a quarter. The shaft of the ulna showed lateral compressions. Compared to the modern pangolins, the radius measured along the length of the humerus was very short, its length was 4.9 cm. The longest limb bone represented the thigh bone with a length of 8.5 cm. Its hemispherical head had a femoral head pit that is missing in today's pangolins. The shaft showed narrowing in front and behind. A very robust third roll hillock (trochanter tertius) was formed on the side, which lay slightly below the middle of the shaft. The position was significantly higher than that of today's species, but lower than that of Cryptomanis and Eomanis . A ridge of bone ran up from the third hill, which ended approximately at the level of the small hill (trochanter lesser). The knee joint was built asymmetrically with a larger joint roll on the inside compared to the one on the outside. The tibia became only slightly shorter than the femur. At the upper end of the shaft there was a distinctive bone rib, which extended vertically downwards over about two thirds of the shaft length and thus reached further down than in Cryptomanis or the more recent forms. There were also other noticeable bone marks, such as a depression in the hollow of the knee. Compared to the shin, the fibula was significantly shorter at 6.8 cm, the length ratio of the two bones to each other shows a lower value than in comparison with Cryptomanis or the modern forms. Hands and feet are made up of five rays each. Typical of pangolins, a bony prehallux appeared on the foot, a bone in front of the big toe, which in Patriomanis was pressed sideways and was not as cylindrical as in Cryptomanis . It was more like the prehallux of today's pangolins. At the wrist, the scaphoid bone and the moon bone were fused together and formed a scapholunar element, which is also found in all recent species. The central ray on the hand and foot was only slightly enlarged compared to the modern pangolins; in contrast to these, the metacarpal and metatarsal bones in particular were noticeably elongated. The third metacarpus reached a total length of 2.2 cm, which corresponds to about 28% of the length of the humerus; in recent forms this value is less than 25%. Correspondingly, the third metatarsus measured 2.8 cm, which in turn makes up 35% of the length of the tibia, in the case of today's species it is again less than 25%. In contrast, today's pangolins have enlarged end links on the fingers and toes, which clearly exceed the other phalanges in length and massiveness - depending on the species, the respective end phalanx can be two to three times longer than the middle one - and have robust claws. In contrast to this, Patriomanis had hardly any enlarged end links, the dimensions of which corresponded more to the other phalanges, which made the hands and feet appear less massive. In keeping with their modern counterparts, the ends of the last phalanges were deeply slit, the slit serving as the attachment point for the claw.
Fossil finds
Pangolins belong to the rare fauna elements in the fossil record , which on the one hand is due to their rare, solitary occurrence in forests, on the other hand, fossils of this group are difficult to identify due to the toothless and largely delicate skull structure. Patriomanis is the only known representative of the pangolin that has so far been discovered in North America . A total of six individuals are recorded, two of which are represented by almost complete skeletons, three are in the form of partial skeletons or partially articulated skeletal parts, while the last one only found a forearm bone. The skeletons and partial skeletons all come from the Flagstaff Rim , an important fossil deposit of the White River Formation in Natrona County in the central area of the US state Wyoming . The White River Formation is a rock unit that is widespread from the central Rocky Mountains to the Great Plains and consists of fine-grained deposits of terrestrial origin. The sediment sequence is interrupted by several volcanic formations. The vertebrate fossils embedded in the deposits are among the most extensive of their time in the world. The White River Formation as a whole dates to the Upper Eocene and the Oligocene , which roughly corresponds to the period from 38 to 23 million years ago. The patriomanis finds were in different stratigraphic positions. The holotype (a partial skeleton) and another complete skeleton were only 3 to 4 m apart, just above a layer rich in volcanic ash ( Ash F ), they form the chronologically youngest individuals. The second complete skeleton was found about 80 m below the position of the holotype in a clay layer near the base of another layer of ash ( Ash A ) and should represent the oldest representative of the series of finds. Another partial skeleton was 35 m higher than the latter not far from the Ash-D layer. The third partial skeleton also came to light in the vicinity. The entire find area is placed in the end of the Eocene and belongs to the local stratigraphic level of the Middle Chadronian , so it should be between 36.6 and 34.8 million years old, the range of around 2 million years also corresponds to the spread of the Patriomanis finds . The singular forearm bone comes from the Renova Formation in the Jefferson River basin in Montana , about 500 km north of the Flagstaff Rim . The age is comparable to that of the other finds.
Paleobiology
In general, Patriomanis is somewhat smaller, but has a similar structure to its close relative Cryptomanis from northern Asia . Although it lacks the general robustness of the latter, numerous anatomical features also indicate a burrowing way of life in Patriomanis . These include, for example, the strong Large and Third Rolling Hill on the thigh bone, the deltopectoral ridge on the humerus or the bone ridge at the upper end of the shin or the protruding olecranon on the ulna. In these traits, Patriomanis surpasses today's pangolins. Similar to Cryptomanis , the hand and foot elements are not as strongly developed in Patriomanis as compared to the more recent forms, which is mainly expressed in the less prominent third ray and its claw. Accordingly, the Patriomanidae seem to have been adapted to a slightly different shape of the ditch in the underground compared to today's pangolins, in which mainly the upper sections of the limbs were used, less the hands and feet. This also shows an anatomical shift in the characteristics of excavation qualifications during the tribal history of pangolins. The very long tail, consisting of 36 individual vertebrae, was similar to that of today's tree-climbing pangolins. These use their tails as a grasping organ for locomotion in the branches. The individual tail vertebrae are therefore equipped with strong transverse processes and also with chevron bones as an attachment point for the massive tail muscles. Both can also be found in Patriomanis , so that the tail was most likely used as a prehensile tail, which then also supported climbing in the trees. This distinguishes Patriomanis from Cryptomanis , in which strong appendages on the caudal vertebrae were missing, so that this did not have a prehensile tail.
In principle, the toothless, tubular snout indicates that Patriomanis, like today's pangolins, was a specialized myrmecophagous insect eater, so its main diet consisted primarily of ants and termites . A similar snout is already developed in the most original representatives of pangolins such as Eomanis and can be found in a convergent form in today's anteaters . The skull of Patriomanis , like that of today's pangolins, hardly has any prominent bone marks as muscle attachment points. However, in contrast to the more recent forms, the lower jaw is more robustly developed and still has a small crown and angular process. This implies that the masticatory muscles were largely regressed, but not quite as strong as in today's representatives. Most likely, a long tongue was used to ingest the food, as is typical of extreme myrmecophages such as pangolins or anteaters. In these, the tongue does not attach to the hyoid bone itself, but to the sternum via the hyoid muscles , the sword extension of which extends characteristically backwards. The sternum is only incomplete in Patriomanis , but better preserved in Cryptomanis , whose sword extension shows hardly any deviations from that of today's pangolins.
Systematics
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Internal systematics of the Pholidota according to Gaudin et al. 2009 and Gaudin 2010
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Patriomanis is a genus of the extinct family of Patriomanidae . The family was introduced in 1998 by Frederick S. Szalay and Friedemann Schrenk , and at that time it comprised all known fossil pangolins. However, some very early phylogenetic forms such as Eomanis from the Middle Eocene of the Messel Pit show even more basal features that no longer occur in the later forms, including today's pangolins. These include, for example, the unslit terminal phalanges on the hands and feet or the less strongly curved articular processes of the lumbar vertebrae. For this reason, Gerhard Storch referred Eomanis into a separate family, the Eomanidae, in 2003 . This was confirmed in a revision of the pangolins by Timothy Gaudin in 2009, according to which the Patriomanidae only contain Cryptomanis from the Upper Eocene of Central Asia in addition to Patriomanis . Another form, Necromanis , which was widespread in Eurasia from the Oligocene to the Miocene , formed the sister group of the Patriomanidae in the revision . Further phylogenetic investigations, which went hand in hand with the discovery of new fossil material from Necromanis , suggest, however, that the genus should also be classified in the Patriomanidae. The Patriomanidae and Manidae together form the superfamily of the Manoidea .
The genus Patriomanis was first scientifically described by Robert J. Emry in 1970 . For this he had a partial skeleton (copy number F: AM 78999) from the Flagstaff Rim site of the White River Formation . This was discovered in 1957 during a field expedition by the Frick Laboratory led by Morris F. Skinner in outcrops in the Lone Tree Gulch valley around 9 km north-northwest of the village of Alcova in Natrona County of Wyoming . The partial skeleton is composed of a fragment of the posterior skull and parts of the spine and the musculoskeletal system. The generic name Patriomanis consists of the Latin word patria ("home", "fatherland") and the scientific name Manis for today's (Asian) pangolins. The only recognized species is Patriomanis americana (introduced by Emry under the name Patriomanis americanus ), the specific epithet referring to the distribution in North America. It is possible that the stratigraphically oldest find, an almost complete skeleton, represents a different chronospecies, as the find is around 80 m below the holotype (and so far the most recent evidence in stratigraphy). The time span between the two finds is around 2 million years, and the older partial skeleton comes from a noticeably smaller individual.
Today pangolins are restricted to the tropical regions of Asia and Africa . Its origin is believed to be in the northern hemisphere, probably Eurasia . The oldest evidence comes from the Messel Pit in Germany, the findings of which date to the Middle Eocene . This is significantly further north than the current geographic occurrence of pangolins. During this time, however, tropical rainforests were spread far into the north due to more favorable climatic conditions . Presumably, the pangolins reached North America via eastward migrations and passed the Bering Bridge . In the Upper Eocene, around 40 million years ago, Cryptomanis was found in Mongolia in northern Asia . The fossil remains of Patriomanis are a bit younger again, the time span between the first records in the Messel Pit and in North America is about 10 million years. The discovery of pangolins in Europe and North America makes it likely that the animals were distributed over much of Eurasia during the Middle and Upper Eocene. However, during this geological period, as a result of climate deterioration and gradual desiccation, the tropical forests declined, in the subsequent Oligocene and Miocene pangolins were only found in Europe and in southern Asia.
literature
- Robert J. Emry: A North American Oligocene pangolin and other additions to the Pholidota. Bulletin of the American Museum of Natural History 142, 1970, pp. 455-510
- Robert J. Emry: The Edentulous Skull of the North American Pangolin, Patriomanis americanus. Bulletin of the American Museum of Natural History 285, 2004, pp. 130-138
- Timothy J. Gaudin, Robert J. Emry and Jeremy Morris: Skeletal Anatomy of the North American Pangolin Patriomanis americana (Mammalia, Pholidota) from the Latest Eocene of Wyoming (USA). Smithsonian contributions to paleobiology 98, 2016, pp. 1–102
Individual evidence
- ^ A b c d e Robert J. Emry: A North American Oligocene pangolin and other additions to the Pholidota. Bulletin of the American Museum of Natural History 142, 1970, pp. 455-510
- ^ A b Robert J. Emry: The Edentulous Skull of the North American Pangolin, Patriomanis americanus. Bulletin of the American Museum of Natural History 285, 2004, pp. 130-138
- ↑ a b c d e f g h Timothy J. Gaudin, Robert J. Emry and Jeremy Morris: Skeletal Anatomy of the North American Pangolin Patriomanis americana (Mammalia, Pholidota) from the Latest Eocene of Wyoming (USA). Smithsonian contributions to paleobiology 98, 2016, pp. 1–102
- ↑ a b c Timothy J. Gaudin: Pholidota. In: Lars Werdelin and William Joseph Sanders (eds.): Cenozoic Mammals of Africa. University of California Press, Berkeley, London, New York, 2010, pp. 599-602
- ^ A b Timothy J. Gaudin, Robert J. Emry and Brandon Pogue: A new genus and species of pangolin (Mammalia, Pholidota) from the late Eocene of Inner Mongolia, China. Journal of Vertebrate Paleontology 26, 2006, pp. 146-159
- ↑ a b c Timothy J. Gaudin, Robert J. Emry and John R. Wible: The Phylogeny of Living and Extinct Pangolins (Mammalia, Pholidota) and Associated Taxa: A Morphology Based Analysis. Journal of Mammal Evolution 16, 2009, pp. 235-305
- ^ Frederick S. Szalay and Friedemann Schrenk: The Middle Eocene Eurotamandua and a Darwinian phylogenetic Analysis. Kaupia 7, 1998, pp. 97-186
- ^ Gerhard Storch: Fossil Old World "edentates" (Mammalia). Senckenbergiana biologica 83 (1), 2003, pp. 51-60
- ^ Simone Hoffmann and Thomas Martin: Revised Phylogeny of Pholidota: Implications for Ferae. Journal of Vertebrate Paleontology 31 (Suppl.), 2011, pp. 126A-127A