Palaeotis
| Palaeotis | ||||||||||||
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Skeleton of Palaeotis from the Geiseltal |
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| Temporal occurrence | ||||||||||||
| Middle Eocene ( Lutetium ) | ||||||||||||
| 47.4 to 41.1 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Palaeotididae | ||||||||||||
| Peters , 1988 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Palaeotis | ||||||||||||
| Lambrecht , 1928 | ||||||||||||
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Palaeotis weigelti |
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Palaeotis is an extinct genus of ancient pine birds . It is known for several completely preserved fossil skeletons from the Messel pit and the Geiseltal , which means that the findsdateto the Middle Eocene (47 to 43 million years ago). The representatives of the genus reached about the size of today's crane and inhabited forest landscapes. The first description of Palaeotis was made in 1928 on the basis of some leg bones, but it was wrongly assigned to the bustards . It was not until the mid-1980s that a possibly closer relationship with the ostrich was recognized .
features
Palaeotis was a long-legged, flightless bird that reached a total height of less than 1 m, the reconstruction of a skeleton from the Messel Pit resulted in a vertex height of 93 cm, which was about the size of today's crane . The skull was 13.5 cm long and 5 cm wide. It was relatively flat and narrow behind the eyes. The beak had a moderate length, but was much narrower than that of today's ratites . The palatine bone still had a very primitive shape with backward-pointing bony appendages, roughly comparable to the cockchafer and the extinct lithornis . The typical square leg and the wing bone formed a complex connection with each other, which included the orbital process of the square leg. Furthermore, the ploughshare leg was extremely large. The lower jaw measured up to 13.3 cm and was about 1.2 cm wide at the symphysis .
The short cervical vertebrae and the long extensions of the thoracic vertebrae stand out on the body skeleton. Only three ribs were connected to the breastbone , which is still the case with the rhea today, with the other ratites today there are usually four or more. The collarbone had not yet completely reduced, but was still fused as a narrow bone in the front area with the shoulder girdle (scapulocoracoid). The pelvis had, as with the other modern great jawbirds, but unlike the moas and elephant birds, lateral compressions, whereby the ischium was relatively voluminous. The wings showed an incipient reduction. The humerus bone at 13 cm and the ulna at 9 cm were still relatively long, but the lower wing bones were already significantly shortened. In addition, the humerus lacked the air chambers typical of birds. The thigh bone was relatively short in relation to the lower leg bones, about 14 cm long, and very delicate with rather small joint roles. The tibiotarsus , however, was 25 cm long, the tarsometatarsus 21 cm. Particularly in the tarsometatarsus, deep longitudinal grooves on the midline of the upper and lower sides were found to be characteristic, giving the bone an H-shaped cross-section. The legs ended in three forward-pointing toe rays (ray II to IV), with the middle ray (III) being the longest with a total length of up to 9.4 cm. Overall, the toes were relatively longer than today's large ratites. The end links of the toes had a cylindrical shape and thus indicate that no strongly curved claws were formed.
Fossil finds
Finds from Palaeotis are mainly known from Germany. The most important fossil remains, which also served to establish the genus, include those of the Geiseltal near Halle in Saxony-Anhalt. All fossil finds here come from the Cecilie mining field in the southern Geiseltal and were found in the transition from the Upper Central Coal to the Upper Coal, so they can be placed in the outgoing Middle Eocene around 43 million years ago. The remains include individual bones of the treadmill and the foot as well as an almost complete, but somewhat deformed and partially damaged skeleton. Other outstanding finds were recovered from the Messel pit near Darmstadt in Hesse. It is worth mentioning several skeletons, which are also largely complete. From a geological point of view, the Messel Pit is somewhat older than the Geiseltal, so that the fossils date from the beginning of the Middle Eocene around 47 million years ago.
Paleobiology
The dimensions of the finds suggest two differently sized representatives, which may correspond to a sexual dimorphism , as it also occurs in modern primitive jaws. According to the findings of Messel and the Geiseltal, Palaeotis lived in a wooded area, but with its long legs it was already adapted to a fast-paced ( cursorial ) way of life. Ecologically , Palaeotis corresponds roughly to today's cassowaries , which inhabit tropical rainforests . The actual adaptation to high running speeds of today's large ratites may not have developed until the emergence of open landscapes in the Miocene .
Systematics
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Possible relationship of Palaeotis according to Yonezawa et al. 2017
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Possible relationship of Palaeotis according to Mayr 2015
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Palaeotis is a genus from the now extinct family of Palaeotididae, to which Galligeranoides from the Lower Eocene of southern France may also belong. The family represents a representative of the ancient jawbirds and is often associated with the order of ratites (Struthioniformes), which, however, is paraphyletic from today's perspective . However, this would make Palaeotis largely related to the ostrich ( Struthio ). Originally, Palaeotis was managed within the family of the ostriches (Struthionidae) and relegated there to its own subfamily (Palaeotidinae), but recent studies have shown a separate family status. Differences to the other primitive mandibular birds can be found mainly in the design of the hind legs, which have a bone web (pons supratendineus), which bridges a furrow (sulcus extensorius) on the front of the lower joint end of the tibiotarsus . This creates a canal through which the tendon of the toe extensor muscle passes. Additional deviations can also be noted, for example, on the tarsometatarsus with its wide joint role of the third (middle) metatarsal. The features are more reminiscent of today's crane birds , which, however, belong to the new pine birds . In the case of paleotis , however, a backward-oriented processus supraorbitalis (a bony extension of the frontal bone above the eyes), the remodeling of the shoulder girdle through the fusion of the clavicle and raven bone with the shoulder blade , connected with the reduction of the wings and the sternum ridge (carina sterni) as the starting point of the flight muscles, in addition the laterally narrowed pelvis and the loss of the innermost toe clearly indicate a position within the primitive jaw birds. In contrast to the other ratites of today, however, the beak is significantly narrower.
The exact phylogenetic position of Palaeotis within the primitive pine birds is not clear, which is due to the partly fragmented fossil material. In a cladistic analysis from 2004, Palaeotis and his family forms the sister taxon to all other ancient jawbirds, originally considered ratites, and should therefore be an original representative of this group of birds. Other editors also saw a sisterly relationship with the Nandus . More modern phylogenetic studies from 2015 and 2017 position Palaeotis on the one hand as a sister form of the ostrich, on the other hand as such a group of large flightless birds. Mostly more or less closely related are the flightable Lithornithidae , from which Palaeotis may have emerged and from which fossil finds from Messel were also known.
Today a species is recognized with Palaeotis weigelti . The species and genus were first described scientifically by Kálmán Lambrecht in 1928 on the basis of some leg bones such as the tarsometatarsus and individual limbs from the Geiseltal. These also represent the holotype (copy numbers GM 4415 (right tarsometatarsus, largely lost) and 4418 (phalanx)). Lambrecht originally saw Palaeotis as a fossil representative of the bustards , which is also reflected in the scientific generic name. This is made up of the Greek word παλαιός ( palaiós "old") and Otis as the name for the great bustard . It was not until the mid-1980s, when several complete skeletons were discovered in Messel and Geiseltal, that a closer relationship with ostriches was recognized. Also included in the species Palaeotis weigelti is the synonym Palaeogrus geiseltalensis , which was also described by Lambrecht in 1935 on the basis of articulated leg bones from the Geiseltal. The species name weigelti honors Johannes Weigelt , who significantly advanced research in the Geiseltal in the 1930s and who discovered the first fossil finds from Palaeotis in 1926 or 1927.
literature
- Peter Houde, Hartmut Haubold: Palaeotis weigelti restudied: a small Middle Eocene ostrich (Aves: Struthioniformes). In: Palaeovertebrata Volume 17, 1987, pp. 27-42.
- Gerald Mayr: Hindlimb morphology of Palaeotis suggests palaeognathous affinities of the Geranoididae and other “crane-like” birds from the Eocene of the Northern Hemisphere. In: Acta Palaeontologica Polonica Volume 64 (4), 2019, pp. 669-678, doi: 10.4202 / app.00650.2019 .
Individual evidence
- ↑ a b c Gerald Mayr: Paleogene Fossil Birds. Springer-Verlag, Berlin and Heidelberg, 2009, pp. 1-275 (pp. 28-29).
- ↑ a b c Peter Houde: Ostrich ancestors found in the Northern Hemisphere suggest new hypothesis of ratite origins. In: Nature Volume 324, 1986, pp. 563-565.
- ↑ a b c d e f g Peter Houde, Hartmut Haubold: Palaeotis weigelti restudied: a small Middle Eocene ostrich (Aves: Struthioniformes). In: Palaeovertebrata Volume 17, 1987, pp. 27-42.
- ↑ a b c d e f g Dieter Stefan Peters: A complete skeleton of Palaeotis weigelti (Aves, Palaeognathae). In: Courier Research Institute Senckenberg Volume 107, 1988, pp. 223-233.
- ↑ a b c Gerald Mayr: The middle Eocene European `` ratite '' Palaeotis (Aves, Palaeognathae) restudied once more. In: Paläontologische Zeitschrift Volume 89, 2015, pp. 503-514, doi: 10.1007 / s12542-014-0248-y .
- ↑ a b c Takahiro Yonezawa, Takahiro Segawa, Hiroshi Mori, Paula F. Campos, Yuichi Hongoh, Hideki Endo, Ayumi Akiyoshi, Naoki Kohno, Shin Nishida, Jiaqi Wu, Haofei Jin, Jun Adachi, Hirohisa Kishino, Ken Kurokawa, Yoshifumi Nogi , Hideyuki Tanabe, Harutaka Mukoyama, Kunio Yoshida, Armand Rasoamiaramanana, Satoshi Yamagishi, Yoshihiro Hayashi, Akira Yoshida, Hiroko Koike, Fumihito Akishinonomiya, Eske Willerslev, Masami Hasegawa: Phylogenathomics and Morphology of the Revincteal Ratio. In: Current Biology Volume 27, 2017, pp. 68-77, doi: 10.1016 / j.cub.2016.10.029 .
- ^ Richard O. Prum, Jacob S. Berv, Alex Dornburg, Daniel J. Field, Jeffrey P. Townsend, Emily Moriarty Lemmon, Alan R. Lemmon: A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing. In: Nature Volume 526, 2015, pp. 569-573, doi: 10.1038 / nature15697 .
- ↑ a b Gerald Mayr: Hindlimb morphology of Palaeotis suggests palaeognathous affinities of the Geranoididae and other “crane-like” birds from the Eocene of the Northern Hemisphere. In: Acta Palaeontologica Polonica Volume 64 (4), 2019, pp. 669-678, doi: 10.4202 / app.00650.2019 .
- ↑ Gareth J. Dyke, Marcel van Tuinen: The evolutionary radiation of modern birds (Neornithes): reconciling molecules, morphology and the fossil record. In: Zoological Journal of the Linnean Society Volume 141, 2004, pp. 153-177.
- ^ Kálmán Lambrecht: Palaeotis weigelti ngn sp., A fossil bustard from the Middle Eocene brown coal of the Geiseltal. In: Yearbook of the Hallesches Verband Volume 7, 1928, pp. 1–11.
- ↑ Kálmán Lambrecht: Three new bird forms from the Lutétium of the Geiseltal. In: Nova Acta Leopoldina Volume 3, 1935, pp. 361-367.
