Qiaowanlong

Qiaowanlong
Artistic life reconstruction of Qiaowanlong kangxii .
Temporal occurrence
Lower Cretaceous ( Aptium to Albium )
126.3 to 100.5 million years
Locations
China , Gansu ( Xinminpu Group )
Systematics
Lizard dinosaur (Saurischia) Sauropods (Sauropoda) Neosauropoda Macronaria Titanosauriformes Qiaowanlong
Scientific name
Qiaowanlong
You , Li , 2009
Art
Qiaowanlong kangxii

Qiaowanlong is a genus of sauropod dinosaur and an original representative of the Titanosauriformes from the late Lower Cretaceous China .

So far, only a fragmentary skeleton is known, which consists of a cervical vertebra series of eight vertebrae and the right pelvis and was discovered in northwestern Gansu . This find can be dated to the late Lower Cretaceous ( Aptium to Albium ). Although it was initially referred to as the first member of the Brachiosauridae discovered in Asia, a recent study shows that it was more closely related to the original titanosaur forms Erketu and Euhelopus . The only species is Qiaowanlong kangxii .

description

The fossils likely belonged to an adult or near-adult specimen. The eight known vertebrae were discovered anatomically linked to one another; it was probably a series from the fourth to the eleventh cervical vertebrae. The cervical vertebrae were significantly shorter than the greatly elongated cervical vertebrae of the brachiosaurids: For example, the seventh cervical vertebra was 45 centimeters long, while the corresponding one in Giraffatitan was 93 centimeters long. The spinous processes of the cervical vertebrae were deeply forked, a feature that can only be found in related genera in Erketu . The ischial (ischium) was as with other representatives of the Somphospondyli downsized and made only 70% of the length of the pubic bone (pubis) out. In contrast to other genera, the pubic crest of the ischium was very long and made up over 60% of the shaft length.

Systematics

When it was first described by You and Li (2009) , Qiaowanlong was classified within the Brachiosauridae. According to these authors, qiaowanlong showed similarities in particular with sauroposeidone . Daniel Ksepka and Mark Norell contradicted this hypothesis and recognized Qiaowanlong as the original representative of the Somphospondyli, a group that includes Euhelopus , Erketu and the Titanosauria . Like Erketu , Qiaowanlong showed bifurcated spinous processes of the cervical vertebrae, which according to these researchers indicates that both genera were closely related and formed a clade . Erketu and Qiaowanlong were believed to be more closely related to the Titanosaurs than to Euhelopus .

The possible family relationships are shown in the following cladogram (simplified from Ksepka and Norell, 2010):

Titanosauriformes	Brachiosauridae    Somphospondyli   Euhelopus     Erketu     Qiaowanlong     Titanosauria

Find, history of discovery and naming

The only known find was unearthed in 2007 by a Chinese research group in the Jiuquan area in northwestern Gansu. During the recovery of the fossil, the series of vortices had to be divided into two parts. The find ( holotype , specimen number FRDC GJ 07-14) was first scientifically described by Hai-Lu You and Da-Qing Li in 2009 . The name Qiaowanlong ( Chinese qiao - "bridge", wan - "bent in a stream", long - "dragon") refers to Qiaowan, a cultural place near the site. The second part of the species name, kangxii , is named after Kangxi , a famous emperor of the Qing Dynasty .

The rocks of the site belong to the middle strata of the Xinminpu group , a group of the Yujingzi basin . This group has only recently become known to science and contained the fossils of several recently discovered dinosaurs, including the Therizinosauroidea Suzhousaurus , the Tyrannosauroidea Xiongguanlong , the Ornithomimosauria Beishanlong , a new Neoceratopsia and various other finds, including a bonebed of the Hadrosauroidea Equijubus .

Individual evidence

1. ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 204 online .
2. ↑ ^{a b c d e} Daniel T. Ksepka, Mark A. Norell: The Illusory Evidence for Asian Brachiosauridae: New Material of Erketu ellisoni and a Phylogenetic Reappraisal of Basal Titanosauriformes (= American Museum Novitates. No. 3700). American Museum of Natural History, New York NY 2010, (PDF; 448.89 kB) .
3. ↑ ^{a b c d e} Hai-Lu You, Da-Qing Li: The first well-preserved Early Cretaceous brachiosaurid dinosaur in Asia. In: Proceedings of the Royal Society. Series B: Biological Sciences. Vol. 276, No. 1675, 2009, ISSN  0080-4649 , pp. 4077-4082 doi : 10.1098 / rspb.2009.1278 .