[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Iguanodon(?) sp. and Jixiangornis



Neraudeau et al., 2003. A new Early-Cenomanian paralic deposit with fossil wood, amber with insects and Iguanodontidae (Dinosauria, Ornithopoda) at Fouras (Charente-Maritime, southwestern France). C.R. Palevol: 221-230

I used Babel Fish to translate the part of the paper describing Iguanodon(?) sp. so I'm little fuzzy on some details. Instead of trying to re-describe the entire thing, I'm copying my translation into this email.

"The remainders of dinosaurs are represented in the layer of Fouras by about fifty osseous fragments, including only one about fifteen decimeteres. Except for a right ulna (Figs. 2.1A and B) and distal end of a tibia (Figs. 2.C and D), these fragments are not for the majority, identifiable with precision.

The preserved ulna is a 25.5 cm long bone. In lateral view, its posterior margin is right[?] and not concave, as in Iguanodon bernissartensis [ 25 ], Iguanodon atherfieldensis [ 26 ] or Ouranosaurus nigeriensis [ 30 ]. The proximal end is widened and has an olecranon process more developed than that of Hadrosauridae. A concavity intended to receive the humerus is arranged on the former face of the olecranon process. Ventral to this concavity, a vertical and prominent osseous peak extends distally for ten centimeters. This peak longitudinally divides the anteroproximal face of the ulna into two concavities. Side concavity thus formed is intended for the articulation with the radius. The section of the proximal end has a form of T at the specimen of Fouras, whereas it is U-shaped in Ouranosaurus [ 30 ]. In Iguanodon atherfieldensis, the longitudinal peak develops proximmally on the anteromedial face of the ulna, then extends distally by dividing the former face from the ulna [ 26 ]. The width of the ulna decreases gradually in front of the proximal end of the ulna, to grow again with the approach of the distal end. The distal end is slightly compressed transversely. It anteromedially presents a light depression of which was to form part the distal end of the radius. Contrary to Ouranosaurus [ 30 ], the distal end is not curved backwards.

The distal end of the right tibia of the specimen of Fouras is lengthened transversely. The malleoli are strongly damaged, but the external malleolus extends distally, definitely further the internal malleolus. The two malleoli are separated by a marked projection. The former face of the distal end is plane, and its strongly convex posterior face as in Camptosaurus prestwichii [ 10(fig. 10-L) ]. This character makes it possible to distinguish the distal extremity from Fouras of those of Iguanodon atherfieldensis and Iguanodon bernissartensis, at which the former and posterior faces of the distal end of the tibia are concave [ 25, 26 ].

If the two bones described previously are clearly identifiable like pertaining to Iguanodontidae, their attribution with the genus Iguanodon remains dubious. The remainders of Iguanodontidae are largely represented in the European layers of the lower Cretaceous, and two species, Iguanodon bernissartensis [ 3 ] and Iguanodon atherfieldensis [ 14 ], were described in detail [ 25, 26 ]. The genus Rhabdodon [ 17 ], is only Iguanodontidae known in the higher Cretaceous (Campanien and Maastrichtien) of Western Europe. Although it is present in many European layers [ 1, 4, 11, 15, 27 ], its membership of Iguanodontidae only was recently suggested [ 29 ]. The discovery of new remainders of Iguanodontidae in lower Cénomanien of the layer of Fouras brings to us significant data from a point of view biostratigraphic. If the membership of the Iguanodon kind can be confirmed by new discoveries, it will extend the stratigraphic distribution of this genus to the higher Cretaceous. This discovery stresses also the importance of the layer of Fouras: the vertebrate remainders continental ones in general, and dinosaurs in particular, are indeed very rare in France for the period extending from Cénomanien in Santonien [ 6 ]."

-------------------------------------------------------------

Ji Qiang, Ji Shuan, Zhang Hongbin, You Hailu, Zhang Jianping, Wang Lixia, Yuan Changri, & Ji Xinxin, (2002). A new Avialian Bird - Jixiangornis orientalis gen. et sp. nov. - from the Lower Cretaceous of Western Liaoning, NE, China. Journal of Nanjing University (Natural Sciences) 38(6): 723-736

From the Abstract-
"A well-preserved specimen of an avialian bird with a complete skull and postcranial bones was found from the lower part of the Yixian Formation (Early Cretaceous) in Sihetun area of Beipiao City, western Liaoning, NE China. It is characterized by the development of a beak, the large sternum with a weak keel, the typical U-shaped furcula, the forelimbs much longer than the hindlimbs (about 131:100) and the long tail with about 27 caudal vertebrae. Due to the characters mentioned above, the new avialian bird is surely capable of flight stronger than Shenzhouraptor and Archaeopteryx. It is described in detail and named as Jixiangornis orientalis gen. et sp. nov. in this paper."

Ji et al. assign it to the Avialae (Gauthier, 1986)

Material- premaxilla, nasal, frontal, lacrimal, maxilla, orbit, jugal, quadrate, dentary, hyoid, cervical vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, scapula, furcula, sternum, uncinate processes, sternal ribs, coracoids, dorsal ribs, gastralia, manus (MC I, MC II, MC III, M I-1, M II-1, II-2, III-3, radiale, semilunate carpal, radiale), ulna, radius, humerus, ilium, ischium, pubis, femur, tibiotarsus, fibula, calcaneum, astragalus, complete pes

The premaxilla is not tapered rostrally. The maxilla contacts external naris. Nasals are rostrodorsally depressed (?). Premaxillary teeth absent are absent. Maxillary teeth are absent. The antorbital fenestra has not been lost.

The dentary teeth are absent. The dentary is rostroventrally curved. The external mandibular fenestra is present. The dentary is ~60-75% of mandibular length. The posteroventral process of the dentary is very long, and extends for most of the length of the external mandibular fenestra.

There are quadrangular lateral processes on sternum. The sternal plates are ossified and co-fused with a midline keel. The furculae is robust and U-shaped. The acromion process of the scapula appears to be prominent, triangular, and perhaps cranioventrally directed. The superficial surfaces of coracoid face anteriorly. There are ossified uncinate processes.

The metacarpals are not fused to each other or to the semilunate carpal. The semilunate carpal covers the proximal bases of metacarpals I, II, and III. Metacarpal I is 10% or less the length of metacarpal II. Metacarpal III is bowed posterolaterally. Manual phalanx I-1 is slightly bowed. Manual ungual I is shorter than manual ungual II, and less curved. Manual phalanges II-1 and II-2 are nearly subequal. Only III-3 and the ungual as far as the phalanges go for manual digit III. Manual phalanx II-1 is expanded transversely. The ulna is longer than the humerus. The humerus appears to have a hatchet-shaped deltopectoral crest.

The astragalus and calcaneum are proximally fused to the tibia, but I presume not to each other since they are referred to as separate elements? The metatarsus is proximally fused to each other and to the distal tarsals. The hallux is retroverted. Pedal ungual II is larger and more curved than III. Pedal phalanx II-1 is shorter (~75%) than II-2. Pedal digit IV is nearly as long as III and much longer than II. The distalmost phalanges are the longest in all the digits. I cannot tell if pedal digit II is hyperextendible. The tibia is longer than femur.

The tail is 5-7 times the length of the femur.

Figure 5 is the uhm... quote "sketchy cladogram of dinosaur-bird phylogenetic relationship, showing that Shenzhouraptor sinensis Ji et al. 2002 and Jixiangornis orientalis gen. et sp. nov. from western Liaoning of China are the oldest birds with a real ability of active flight in the world." Here it is-

-- Avialae
     |-- Archaeopteryx
     `-- Orthavialae
         |-- Shenzhouraptor
         `-- Euavialae
             |-- Jixiangornis
             `-- Pygostylia
                 |-- Confuciusornithidae
                 `--+-- Enantiornithes
                    `-- Ornithurae
                        `-- Aves




~~~~

Nick Gardner

_________________________________________________________________
Add photos to your messages with MSN 8. Get 2 months FREE*. http://join.msn.com/?page=features/featuredemail