A large iguanodont from the Upper Barremian of the Paris Basin

The remains of an ornithopod dinosaur from the Upper Barremian (Lower Cretaceous) of Auxerre (Burgundy, France) are described. They consist of several vertebrae and a fragmentary scapula. Despite obvious morphological and dimensional affinities with the species Iguanodon bernissartensis, the state of the specimen does not allow any identification more precise than Iguanodontia indet. Reappraisal of the French Upper Barremian record of medium and large-sized ornithopods reveals that no specimen can be definitely determined to the specific level.     

Systematics of hypsilophodontidae and basal Iguanodontia (dinosauria: Ornithopoda)

The phylogenetic relationships of species attributed to the ornithopod family Hypsilophodontidae are evaluated using morphological characters from the skull, dentition, and postcranium. Based on our analyses, Hypsilophodontidae constitutes a monophyletic taxon that comprises the sister taxon to Iguanodontia, together forming Euornithopoda. Three clades within the family are consistently demonstrated: Zephyrosaurus schaff+Orodromeus makelai, Parksosaurus warreni+Hypsilophodon foxii and Yandusaurus hongheensis+Othnielia rex. Thescelosaurus neglectus is the sister taxon to these six genera and constitutes the basal hypsilophodontid. Tenontosaurus tilletti is the basal member of Iguanodontia, with species of Dryosaurus and Camptosaurus as higher taxa within the clade. To understand the effects missing data may have on tree topology, tree length, and consistency indices, poorly represented characters were secondarily removed from the character matrix. In these analyses, all relationships remain stable, but tree length and consistency index decrease with increasingly more complete culled data sets. An average of 42.5 million years is accumulated as minimal divergence time for the hypsilophodontid and basal iguanodontian relationships described here. These figures underscore the large amount of hypsilophodontid evolution yet unaccounted for in the fossil record.     

A tall-spined ornithopod dinosaur from the Early Cretaceous of Salas de los Infantes (Burgos, Spain)

A tall-spined ornithopod dinosaur from the Pinilla de los Moros Formation (Upper Hauterivian-Lower Barremian) of Salas de los Infantes (Burgos, Spain) is described. The material consists of seven associated axial remains, including five middle dorsal vertebrae, a fragmentary neural spine and a dorsal rib, from a single medium-sized individual. This material was previously referred to Iguanodon cf. fittoni. It is characterised by having a high dorsal neurapophysis that is approximately 4.5 times the height of the centrum. The elongation and vertical orientation of the dorsal neural spines allow it to be distinguished from other ornithopods from the Wealden of Europe, including Hypselospinus and Barilium from the Valanginian, and Iguanodon and Mantellisaurus from the Barremian-Aptian. The material is here referred to Iguanodontia indet. because it is so incomplete, but it is potentially a distinct taxon. Among the ornithopods, only Ouranosaurus and the hadrosaurid Hypacrosaurus possess higher dorsal neural spines.     

河南内乡桑坪组一新禽龙及其地层学意义

记述了禽龙亚目（Ｉｇｕａｎｏｄｏｎｔｉａ）一个新属种─—诸葛南阳龙（Ｎａｎｙａｎｇｏｓａｕｒｕｓ　ｚｈｕｇｅｉｉ）。标本产于河南内乡夏馆镇桑坪组的紫红色泥质粉砂岩中。它的自近裔特征包括：第二掌骨超过第三掌骨和第四掌骨长度的９０％;第四掌骨远端异常粗壮;指节ＩＶ－１长度小于远端横向宽度;第二跖骨近端腹背向长度大于第三跖骨。系统发育分析表明,南阳龙代表亲缘关系与鸭嘴龙超科最为接近的一类鸟脚类恐龙。诸葛南阳龙的发现支持了夏馆盆地红层为早白垩世沉积的观点。     

An early juvenile specimen of Bolong yixianensis (Ornithopoda: Iguanodontia) from the Lower Cretaceous of Ningcheng County,Nei Mongol,China

We describe an early juvenile specimen (ZMNH M8812) of Bolong yixianensis from the Yixian Formation (Lower Cretaceous) of Ningcheng County, Nei Mongol, China. The specimen consists of an almost complete skeleton preserved two-dimensionally on a slab. The short and deep skull proportions and unfused neurocentral sutures in most preserved vertebrae suggest that the ZMNH M8812 is a juvenile individual. Osteohistological study confirms a very early developmental stage. The study reveals the ontogenetic changes of Bolong for the first time. The specimen revealed one additional autapomorphy for Bolong yixianensis: the lingual face of the maxillary crown is bounded by thickened mesial and distal margins and bisected by a prominent median principal ridge. The study revealed the following ontogenetic trends of Bolong: increased tooth rows in both maxilla and dentary, increased robustness of the jugal and scapula, the radius and ulna become more robust and shorter relative to the hindlimb and the metatarsals become proportionally shorter. ZMNH M8812 represents the first juvenile non-hadrosaurid iguanodontian specimen described from the Lower Cretaceous of eastern Asia.     

On Asian ornithopods (Dinosauria: Ornithischia). 4. Probactrosaurus Rozhdestvensky, 1966

The genus Probactrosaurus was first established for material discovered by a joint Russian/Chinese expedition to the Chinese autonomous region of Neimongol (Inner Mongolia). Fossils were collected at a site named Maorty (= Maortu). Material attributable to ornithopod dinosaurs was considered sufficiently distinct to permit the definition of two species of the new genus: Probactrosaurus gobiensis and P. alashanicus. The former species was based on a considerable quantity of skeletal material, much of which is still to be found in the collections of the Palaeontological Institute (PIN), Moscow. The latter was based on far less well‐preserved specimens, including a holotype (a posterior skull roof) that can no longer be found in the collections of the PIN and which, along with other materials, was reportedly returned to the Institute of Vertebrate Palaeontology and Palaeoanthropology, Beijing. Some remnants of the original material attributed to P. alashanicus have been located in the PIN collections. Both taxa, established by A. K. Rozhdestvensky, are re‐described using all of the available material collected during the early Sino‐Soviet expeditions. Probactrosaurus alashanicus is considered to be a junior subjective synonym of P. gobiensis. Further comparisons are made with the recently described species Probactrosaurus mazongshanensis Lu, 1997. The latter does not appear to be referable to the genus Probactrosaurus. Probactrosaurus is a gracile ornithopod (ranging between 4 and 6 m in length). The skull is unadorned by any form of cranial crest; however, the premaxillary beak is deflected ventrally and the dentition is similar to that seen in more derived hadrosaurid ornithopods. The postcranial skeleton is notable for its gracility, in particular the elongate forearm and manus, and the retention of a small, conical pollex spine. Systematic analysis suggests that P. gobiensis is a derived non‐hadrosaurid iguanodontian ornithopod and the basal sister‐taxon to the clade Hadrosauridae. The phylogeny of currently known iguanodontians is reviewed. © 2002 The Linnean Society of London, Zoological Journal of the Linnean Society, 2002, 136 , 113–144.