| Wamweracaudia | |
|---|---|
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Family: | †Mamenchisauridae |
| Genus: | †Wamweracaudia Mannionet al,2019 |
| Species: | †W. keranjei |
| Binomial name | |
| †Wamweracaudia keranjei Mannionet al., 2019 | |
Wamweracaudia is a large herbivoroussauropoddinosaur from the LateJurassic (155-145 million years ago)Tendaguru Formation ofTanzania,Africa.
During the German expeditions to the Tendaguru inGerman East Africa between 1909 and 1912, paleontologistWerner Janensch supervised the excavation of a sauropod tail at "Site G". In 1929, he referred this tail toGigantosaurus robustus.[1]
In 1991,G. robustus was made the separate genusJanenschia.[2] Janensch had referred the tail based on personal observation of a series of finds of comparable material. During theSecond World War much of this was destroyed; also all of his field notes were lost. In a revision of the genusJanenschia byJosé Fernando Bonaparte e.a. in 2000, it was concluded that the tail no longer overlapped known extantJanenschia fossils while the remaining documentation was insufficient to justify a referral.[3] In their study of the osteology ofLusotitan in 2013, Mannionet alii again excluded the tail, specimens MB.R.2091.1–30, fromJanenschia due to its lack of overlap with itsholotype SMNS 12144. They suggested that it may represent the first record ofMamenchisauridae from outside Asia.[4]
The specimen was in 2019 given the new genus and species nameWamweracaudia keranjei by Philip D. Mannion, Paul Upchurch, Daniela Schwarz and Oliver Wings in their re-appraisal ofJanenschia and other presumed titanosaur finds from the Tendaguru. The generic name combines a reference to theWamwera, a tribe inhabiting the region of the find, with aLatincauda, "tail". Thespecific name honours the native foreman leading the team that excavated the tail, Mohammadi Keranje.[5]
Wamweracaudia is known from the holotypeMB.R.2091.1–30, MB.R.3817.1 & MB.R.3817.2, found in a layer of the Tendagaru Formation dating from theTithonian. It consists of an almost continuous series of thirty front and middle tail vertebrae, two neural spines of front tail vertebrae, and two chevrons. The tail vertebrae are numbered such that MB.R.2091.30 is the most anterior vertebra of the known series — though not necessarily the first tail vertebra — and MB.R.2091.1 the last one. Probably one vertebra is missing from the series.[5]
The describing authors established fourautapomorphies, unique derived traits. With the front and middle tail vertebrae, the upper surface is excavated at its rear. With the front tail vertebrae, the neural processes show a rough zone on the upper third part of their side surface, separated from the rough zone of the rear surface by a vertical groove. With the middle to rear vertebrae, the underside is strongly pinched transversely, forming a ridge instead of a distinct flat surface. With the middle to rear vertebrae, the neural processes show an elongated horizontal ridge on their sides, just above the level of theprezygapophyses, the front articulation processes.[5]
Two additional traits are autapomorphies ifWamweracaudia is indeed a mamenchisaurid. The transverse processes or caudal ribs of the front tail vertebrae strongly curve sideways and to the front. With the front tail vertebrae, just in between the outer side of the prezygapophysis and the tip of the upper side of thediapophysis, the top rib facet, a pair of small extensions, ortubercula, is present.[5]
An exactcladistic analysis, part of the 2019 study, showed thatWamweracaudia was placed in the Mamenchisauridae, as asister species ofMamenchisaurus. The two taxa shared procoelous tail vertebrae. These are also present in theTitanosauria and when the tail was still referred to it,Janeschia had been seen as one of the earliest known titanosaurs.[5]
As a sauropod,Wamweracaudia would have been a largequadrupedalherbivore.[6]
