Abstract We re-examine a Lower Cretaceous dinosaur tracksite at Boltodden in the Kvalvågen area, on the east coast of Spitsbergen, Svalbard. The tracks are preserved in the Helvetiafjellet Formation (Barremian). A sedimentological characterization of the site indicates that the tracks formed on a beach/margin of a lake or interdistributary bay, and were preserved by flooding. In addition to the two imprints already known from the site, we describe at least 34 additional, previously unrecognized pes and manus prints, including one trackway. Two pes morphotypes and one manus morphotype are recognized. Given the range of morphological variation and the presence of manus tracks, we reinterpret all the prints as being from an ornithopod rather than a theropod, as previously described. We assign the smaller (morphotype A, pes; morphotype B, manus) to Caririchnium billsarjeanti . The larger (morphotype C, pes) track is assigned to Caririchnium sp., differing in size and interdigital angle from the two described ichnospecies C . burreyi and C . billsarjeanti . The occurrence of a quadrupedal, small to medium-sized ornithopod in Svalbard is puzzling, considering the current palaeogeographical reconstructions and that such dinosaur tracks have mainly been described from Europe but not North America.

ABSTRACT Outcrops of Late Cretaceous Gulf Series strata (Woodbine, Eagle Ford, and Austin) in the Dallas area expose middle Cenomanian to the early Campanian (96 to ˜ 83 Ma) rocks, which are well known in the subsurface of the oil-rich East Texas Basin. Together with the underlying Comanche Series and overlying younger Gulf Series, this set of strata provides a record of the last 50 million years of the Cretaceous. Although both marine and terrestrial vertebrates are known in this interval, the Late Cretaceous record is primarily marine. On this field trip, sites are visited that have yielded sharks, bony fish, turtles, dinosaurs, crocodiles, pterosaurs, mammals, long- and short-necked plesiosaurs, and a classic record of mosasaur evolution.

Abstract Vertebrate footprints have been discovered in recent years from seven Mesozoic formations of Thailand and Laos dating from the Late Triassic (Kuchinari Group) and the Early Cretaceous (Khorat Group). The sites are reviewed here in chronological order. The ichnological record reflects fairly well the broad picture of the evolution of continental vertebrates in Asia known from the skeletal record. Norian basal archosaurs are replaced by Rhaetian dinosaurs although both footprint morphotypes look different from the contemporaneous European and North American forms. Two successive ornithopod radiations can be observed in the Early Cretaceous, with primitive small tetradactyl Hypsilophodon -like dinosaurs in the Earliest Cretaceous followed by advanced iguanodontoids with tridactyl fleshy footprints in the Aptian. Late Early Cretaceous dinosaur footprints from NE Thailand, however, do not validate previous hypotheses on the geographical distribution of Cretaceous ornithopod tracks in Asia. The ichnological record also reveals a hitherto unsuspected high diversity of theropods in the early Cretaceous with many different morphotypes.

Abstract The Cretaceous Western Interior Seaway experienced several transgressive/regressive cycles during its existence. The Greenhorn Cyclothem, the sixth such cycle, is significant because of the symmetry of deposition, and because of the expression of cyclical climatically influenced deposits within. This field trip will illustrate evidence of both of these cycles.

Abstract Tracks of small quadrupedal ornithischians with five manual and four pedal digits have been recorded from sedimentary rocks near the Late Jurassic–Early Cretaceous (Tithonian–Berriasian) boundary in NE Thailand and British Columbia. These are compared with larger tracks of gracile, quadrupedal ornithopods from the earliest Cretaceous of Spain and smaller tracks of a quadruped of unknown age from Zimbabwe. The Thai and Canadian tracks are similar to the Early Jurassic (Liassic) ichnogenus Anomoepus and the small ornithopod tracks from the Late Jurassic of Spain. They are the only known post-Liassic ornithischian tracks in which up to five discrete manus digit impressions are clearly visible. Based on strong heteropody (manus much smaller than pes) in all cases we infer an ornithopod trackmaker rather than another ornithischian. The scattered, but widespread earliest Cretaceous occurrence of this ichnotaxon, herein assigned to Neoanomoepus perigrinatus ichnogen. and ichnosp. nov., on the basis of type material from Canada, suggests that these hitherto unknown earliest Cretaceous ichnofaunas may represent a radiation of small basal ornithopods (pes length less than 15 cm), appearing before the widespread radiation of large ornithopods (pes length up to 60 cm or more) later in the Neocomian (Valanginian–Barremian), Aptian–Albian and Late Cretaceous. The primitive condition of the trackmaker is indicated by the pedal and manual morphology, which consists of four and five digits respectively that are not enclosed by well-developed fleshy padding or integument. In contrast, all larger Cretaceous ornithopod tracks, mostly from post-Berriasian strata, have only three pedal digits enclosed in fleshy pads and a manus in which all functional digits are reduced and enclosed by substantial flesh.

Abstract Ichnology straddles the boundary between palaeontology and sedimentology, and is becoming an increasingly important tool in both fields. For the palaeontologist, trace fossils allow insight into behaviour and biomechanics of animals that would otherwise be the subject of conjecture. For the sedimentologist, trace fossils have a marked impact on the interpretation of sedimentary rocks in that they destroy primary sedimentary structures, but can also reveal subtle palaeoenvironmental information beyond the resolution attainable by analysis of primary physical sedimentary structures. This contribution aims to review the major developments in the field of ichnology, and to highlight some of the tools and approaches currently used by ichnologists. A personal ethos for the study of trace fossils in core is outlined as a model ichnological protocol, and some of the frontiers of the science as a whole are briefly discussed.

Abstract: Organisms are homeostatic organic wholes. Their organization is understandable, and fractally repeated, from the level of the cell to whole individual organisms, through higher taxonomie groups up to the level of the biosphere. This is not fully appreciated by most biologists and paleontologists owing to emphasis on investigation of the parts (individual organs) that constitute static anatomy, rather than the dynamic morphological interrelationships. The morphodynamic approach, which is largely synonymous with a holistic heterochronic approach, also allows us to view organisms as complex systems: i.e., as manifestations of iterative or recursive fractal organization. Using the Schadian paradigm, already successfully applied to an understanding of modern mammals, and the relationships between morphology (form), physiology, and behavior, it is possible to gain insight into reiterating, recursive, or fractal patterns of organization in dinosaurs, pterosaurs, and other extinct archosaurs. Once these whole-body morphodynamic relationships are understood, as inherent, intrinsic, or “formal” aspects of vertebrate development, all natural groups of organisms can be seen in a new light: i.e., recurrent patterns of morphological organization (convergence) are seen as necessary correlates of physiological organization and behavior. In turn, all these organic attributes help us understand dynamic evolutionary development of any natural taxonomic group (clade). Thus, ontogeny reiterates and creates phylogeny (and vice versa) in a series of fractal, recursive manifestations of form, physiology, and behavior. Appreciation of the intricacy of this complex fractal organization is an exercise in pattern recognition, with surprising implications, especially for paleontology. First, it confirms the interrelatedness of all organisms, one of the central tenets of modern evolutionary theory. Second, it supports the view that higher natural taxonomic groups, already recognized by biology and paleontology, are in reality superorganisms, with inherently similar organizational structure, modified only by spatial and temporal scaling (heterochrony). Thus, all have their own inherent spatio-temporal developmental trajectories (form, life span, and relative emphasis of proximal and distal—or inner and outer/peripheral organs). Third, convergence and iterative evolution can be understood as an inherent quality of a reiterating or recursive fractal system and not merely as an adaptation to external pressures of the environment. This inference is strongly supported by evo-devo studies. Fourth, the modification of the natural organic system, in part or wholly, will lead to a compensation or ripple effect throughout the whole system. Moreover, the phylogeny of a particular group may not be controlled by external environmental pressures to the degree often supposed. Rather, such phylogenies may be natural heterochronic cycles of repeated growth at levels of organization corresponding to higher taxonomic groups (= superorganisms). Such intricate, inherent (or formal) organic organization reveals lawful patterns of morphological relationships that extend beyond isolated and/or shared character recognition. Thus, it may be possible to predict the general form and physiology of the whole animal from an analysis or understanding of the parts (a process akin to modeling). This is particularly useful in paleontology. The morphodynamic approach does more than revive Cuvier’s principle of the correlation of “some” parts. It impels us to recast our previously static understanding of morphology in the light of the inherently dynamic nature of complex systems, showing us how “all” parts are ultimately related.