Weigeltisaurus
| Weigeltisaurus | |
|---|---|
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| Specimen SMNK-PAL 2882 | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Family: | †Weigeltisauridae |
| Genus: | †Weigeltisaurus Kuhn, 1939[1] |
| Species: | †W. jaekeli
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| Binomial name | |
| †Weigeltisaurus jaekeli (Weigelt, 1930)
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| Synonyms | |
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Weigeltisaurus is an extinct genus of weigeltisaurid reptile from the Late Permian Kupferschiefer of Germany and Marl Slate of England. It has a single species, originally named as Palaechamaeleo jaekeli in 1930 and later assigned the name Weigeltisaurus jaekeli in 1939, when it was revealed that Palaeochamaeleo was a preoccupied name. A 1987 review by Evans and Haubold later lumped Weigeltisaurus jaekeli under Coelurosauravus as a second species of that genus.[2] A 2015 reassessment of skull morphology study substantiated the validity of Weigeltisaurus and subsequent authors have used this genus.[3][4] Like other Weigeltisaurids, they possessed long rod-like bones that radiated from the trunk that were likely used to support membranes used for gliding, similar to extant Draco lizards.
History of discovery
The first remains of Weigeltisaurus jaekeli were described by Johannes Weigelt in 1930 from a specimen (SSWG 113/7) found in the
The same year, Friedrich von Huene noted the similarity of the specimen to Coelurosauravus elivensis from Madagascar, which had been described by Jean Piveteau in 1926, and concluded that both animals were closely related and represented climbing reptiles. In 1939, Oskar Kuhn noted that Palaeochamaeleo had already been used in a different publication in 1903, and proposed the new genus name Weigeltisaurus in honour of Weigelt.
In publications in 1976 and 1986, Günther Schaumberg described additional specimens of Weigeltisaurus from the Kupferschiefer of Germany. Due to the fact that the bony rods were also present on these skeletons, and the fact that the rods were only superficially similar to coelacanth spines, Schaumberg (1976) argued that they represented parts of the animals skeleton and were used for gliding flight, stating that the presence of the bones "...virtually provokes the attempt to explain its function for flight characteristics.".
In 1987, Evans and Haubold proposed that Weigeltisaurus jaekeli represented a species of Coelurosauravus, and synonymised Gracilisaurus ottoi, which had been described from a disarticulated postcranial skeleton from the Kupferschiefer by Weigelt in 1930 with Weigeltisaurus jaekeli.
In 2007, Schaumberg, Unwin and Brandt presented and discussed new skeleton details of Weigeltisaurus, the mechanism of unfolding and folding the patagium and presented thin-sections of the rods with lamellar bone.
In 2015 in two separate publications, V. V. Bulanov & A. G. Sennikov redescribed Coelurosauravus elivensis and Coelurosauravus jaekeli and concluded that the generic separation should be maintained, restoring Weigeltisaurus as a valid genus.
In 2021, an extensive description of a mostly complete specimen of Weigeltisaurus (SMNK-PAL 2882) was published, this specimen was collected in 1992 from near the town of Ellrich in Saxony-Anhalt, and had briefly been described in a 1997 publication in Science.[7][8] The counterpart of the specimen is in private collection and inaccessible to researchers.[7]
List of specimens
- Greifswald specimen (SSWG 113/7): Holotype of Palaeochamaeleo/Weigeltisaurus/Coelurosauravus jaekeli (Weigelt, 1930). A partial skeleton including a well-preserved skull, vertebrae, limbs, and gliding structures.
- GM 1462: Holotype of Gracilisaurus ottoi (Weigelt, 1930). A partial skeleton including a forelimb, neck vertebrae, skull fragments, and gliding structures.
- Wolfsberg & Cornberg specimens: Privately owned specimens described by Schaumberg (1976).
- Eppleton specimen (TWCMS B.5937 1&2): A well-preserved partial skeleton including the torso, hindlimbs, part of the tail, and gliding structures all in articulation. The only Coelurosauravus specimen known from England, specifically the Marl Slate near Hetton-le-Hole, Tyne and Wear. First described in Nature by Pettigrew (1979).[6]
- Bodental specimen: A privately owned specimen described by Schaumberg (1986).
- Ellrich specimen (SMNK 2882 PAL): A well-preserved and fully articulated complete skeleton first described in Science magazine by Frey, Sues, & Munk (1997).[8]
Description
Gliding
The gliding membrane of weigeltisaurids is distinct from those of other gliding reptiles, which originate from modified ribs originating from the upper-lateral surface of the body. In contrast, in weigeltisaurids, the rods originate from the lower-lateral surface of the body. The furling and unfurling of the gliding membrane were likely controlled by the abdominal muscles. Preserved fossils show that the bony rods had a high degree of flexibility, similar to the ribs of living gliding lizards. Due to the low-wing configuration, it is likely that the gliding surface was angled upwards to increase stability.[7] In living gliding lizards, it has been found that the forelimbs grab hold of the front of the membrane during takeoff, and are used to adjust the trajectory mid-flight. Similar behaviour has been proposed for weigeltisaurids.[9] In a 2011 study comparing Coelurosauravus and other extinct gliding reptiles to modern Draco species, Coelurosauravus was found to be a less efficient glider due to its larger body size, with a steep descent angle of over 45 degrees and a consequent substantial drop in height per glide.[7][10]
Paleoenvironment
The Kupferschiefer and the equivalent Marl Slate is a marine unit that forms part of the