Humeral morphology of the early Eocene mekosuchine crocodylian Kambara from the Tingamarra Local Fauna southeastern Queensland,Australia

Stein, M., Salisbury, S.W., Hand, S.J., Archer, M. & Godthelp, H., December 2012. Humeral morphology of the early Eocene mekosuchine crocodylian Kambara from the Tingamarra Local Fauna southeastern Queensland, Australia. Alcheringa 36, 473–486. ISSN 0311-5518.

Mekosuchines (Crocodylia; Crocodyloidea) were a clade of crocodylians endemic to Australia and the South Pacific that underwent radiation during the Cenozoic. Numerous questions about mekosuchine palaeoecology remain unanswered. Tantalizing among these is the possibility that some mekosuchines were primarily terrestrial. To date, studies of mekosuchines have focused mainly on the cranium. However, the morphological signal for terrestriality is more likely to be found in the postcranial skeleton. Here, we present a comparative morphological study of fossil humeri referable to Kambara from the early Eocene Tingamara Local Fauna, Murgon, southeastern Queensland. The humeri of Kambara do not show the torsion between the proximal and distal extremity seen in extant crocodylians, illustrated here with Crocodylus porosus and Crocodylus johnstoni. They also differ in the structure of the medial and lateral condyles of the distal extremity. When the effects of these features on musculature and articulation are considered, it appears that the forelimb of Kambara could have facilitated a greater force at the glenohumeral joint and possibly swung the lower forelimb faster with a greater arc of motion than Australia's extant crocodylians. This is conducive to an improved capacity for both terrestrial locomotion and paraxial swimming. Although the former case suggests that Kambara may not have been as closely tied to water as extant crocodylians, it is unusual given the typically broad rostra of the cranium. Among crocodylians this is a common characteristic of semi-aquatic ambush predators. This study shows the utility of the postcranial skeleton in interpreting crocodylian palaeoecology.

Michael Stein [michael.stein@student.unsw.edu.au] (corresponding author), Suzanne J. Hand [s.hand@unsw.edu.au], Michael Archer [m.archer@unsw.edu.au] and Henk Godthelp [h.godthelp@unsw.edu.au], School of Earth and Environmental Science, University of New South Wales, Sydney, NSW, 2052, Australia; and Steven W. Salisbury [s.salisbury@uq.edu.au], School of Biological Sciences, University of Queensland, Brisbane, Qld, 4072, Australia. Received 13.1.2012, revised 24.2.2012, accepted 28.2.2012.     

Producer Services,Transaction Activities,and Cities: Rethinking Occupational Categories in Economic Geography

Applying insights from 'new institutional economics' to classify economic activities or occupations avoids some problems for which conventional classifications of services and particularly producer services have long been criticized. In institutionalist thinking the mixture of organizational forms such as market, hierarchy or network in an economy is mainly determined by transaction costs, which can in turn be correlated to specific 'transaction activities'. Typical transaction activities can be identified in markets and in other institutional arrangements, allowing the classification of real economic activities, occupations or firms as transactional or not. Many other commonly applied labels like informational related activities appear comparatively imprecise. This categorization and differentiation sheds new light on discussions about spatial development, from the world city debate to claims about the presumed role of high-tech occupations in metropolitan areas. It is argued that transactional occupations, especially those requiring higher qualifications, can be expected to be highly concentrated in larger agglomerations. In contrast, many non-transactional occupations though requiring high qualifications and usually also regarded as basic for metropolitan economies, like parts of R&D, are not necessarily concentrated there.     

The Task of the Historian

Book reviewed in this article:
Gabrielle M. Spiegel, The past as Text: The Theory and Practice of Medieval Historiography     

How Risk Perceptions Influence Evacuations from Hurricanes and Compliance with Government Directives

In this study we present evidence supporting the view that people's perceived risk of hurricane‐related hazards can be reduced to a single seriousness score that spans different hurricane‐induced risk types and that compliant behavior with official advisories is strongly dependent on whether one perceives a high risk with respect to any type of hurricane‐related hazards. Our analysis suggests that people are less sensitive to risk type than they are to the general seriousness of the risks. Using this single seriousness score, representing a composite risk measure, emergency managers can be informed about the severity of the public's risk perceptions to impending hurricane hazards and might better craft their public directives in ways that minimize disruptive evacuations and achieve greater compliance with government directives.     

Possible sources of archaeological maize found in Chaco Canyon and Aztec Ruin,New Mexico

Maize played a major role in Chaco's interaction with outlying communities in the southern Colorado Plateau. This paper seeks to determine where archaeological corn cobs brought to Chaco Canyon were grown. Strontium-isotope and trace-metal ratios of 180 soil-water and 18 surface-water sites in the Southern Colorado Plateau have revealed possible source areas for some of 37 archaeological corn cobs from Chaco Canyon and 10 archaeological corn cobs from Aztec Ruin, New Mexico. The most probable source areas for cobs that predate the middle-12th-century drought include several Upper Rio Chaco sites (not including Chaco Canyon). There are many potential source areas for cobs that date to the late A.D. 1100s and early 1200s, all of which lie in the eastern part of the study area. Some Athapascan-age cobs have potential source areas in the Totah, Lobo Mesa, and Dinetah regions. One Gallo Cliff Dwelling cob has a strontium-isotope ratio that exceeds all measured soil-water values. Field sites for this cob may exist in association with Paleozoic and Precambrian rocks found 80–90 km from Chaco Canyon. Potential source areas for most Aztec Ruin cobs (many of which were found in rooms dating to the first half of the 13th-century) appear to be associated with a loess deposit that blankets the Mesa Verde and McElmo Dome regions.     

Development and evaluation of geochemical methods for the sourcing of archaeological maize

Strontium (Sr)-isotope values on bone from deer mice pairs from 12 field sites in the Chaco Canyon area, New Mexico, were compared with isotope values of synthetic soil waters from the same fields. The data indicate that mice obtain Sr from near-surface sources and that soil samples collected at depths ranging from 25 to 95 cm contain Sr that is more accessible to the deep roots of maize; thus, synthetic soil solutions provide better data for the sourcing of archaeological maize. However, the Sr-isotope composition of mice may be more valuable in sourcing archaeological remains of animals such as rabbit, turkey, and deer.     

Heterogeneity, Power, and Political Economy: Some Current Research Issues in the Archaeology of Old World Complex Societies

Recent research on Old World chiefdoms and states has largely retreated from the general comparative explanatory paradigm of the 1970s and has focused instead on more historically oriented analyses of culture-specific developmental trajectories. Both theoretical and empirical work tend to emphasize a heterogeneous, conflict-based model of complex society and political economy. This analytical framework has been quite successful in documenting variation and historically determined patterning in the organization of urbanism, craft production, specialization, and exchange. I present an overview of this research and argue that we now need to reintegrate culturally specific analyses within a modified comparative/generalizing perspective on complexity.