Michael P. Taylor

A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914)

ABSTRACT Although the macronarian sauropod Brachiosaurus is one of the most iconic dinosaurs, its popular image is based almost entirely on the referred African species Brachiosaurus brancai rather than the North American type species Brachiosaurus altithorax. Reconsideration of Janenschs referral of the African species to the American genus shows that it was based on only four synapomorphies and would not be considered a convincing argument today. Detailed study of the bones of both species show that they are distinguished by at least 26 characters of the dorsal and caudal vertebrae, coracoids, humeri, ilia, and femora, with the dorsal vertebrae being particularly different between the two species. These animals must therefore be considered generically separate, and the genus name Giraffatitan Paul 1988 must be used for “Brachiosaurus” brancai, in the combination Giraffatitan brancai. A phylogenetic analysis treating the two species as separate OTUs nevertheless recovers them as sister taxa in all most parsimonious trees, reaffirming a monophyletic Brachiosauridae, although only one additional step is required for Giraffatitan to clade among somphospondylians to the exclusion of Brachiosaurus. The American Brachiosaurus is shown to be somewhat different from Giraffatitan in overall bodily proportions: it had a longer and deeper trunk and probably a longer and taller tail, carried a greater proportion of its mass on the forelimbs, and may have had somewhat sprawled forelimbs. Even though it was overall a larger animal than the Giraffatitan lectotype, the Brachiosaurus holotype was probably immature, as its coracoids were not fused to its scapulae.

Theories of local economic growth (part 1): concepts, models, and measurement

Contemporary approaches to understanding the mechanisms determining local economic growth tend to be characterized by a dualism between ‘hard’ quantitative and mathematical models derived from economics and the ‘soft’ qualitative models of geographical theory. In this study, we contribute to a ‘third way’ of knowing that is based upon a theoretically informed econometric analysis of the ‘soft’ processes that are hypothesized to drive local economic growth. In this first of two papers, (part 1 of the study) we focus on questions of methodology and measurement. Specifically, six sets of theoretical propositions on the nature of the mechanisms that promote local economic performance are reviewed: the growth-pole, growth-centres model; the product-cycle model; the flexible-production model; the learning-regions model; the competitive-advantage model; and the enterprise-segmentation model. From this review, eight measurable dimensions are developed that cover the main propositions of these models. These dimensions are calibrated using data for Australia, divided into ninety-four regions, for the period 1984–92. We conclude by exploring the limitations of our mapping between theoretical concepts, measurable dimensions, and surrogate variables, and examine the implications of this mapping for testing the validity of ‘soft’ geographical theories. In a subsequent paper (part 2 of the study) we test the validity of these models of local growth in the Australian context.

Why sauropods had long necks; and why giraffes have short necks

The necks of the sauropod dinosaurs reached 15 m in length: six times longer than that of the world record giraffe and five times longer than those of all other terrestrial animals. Several anatomical features enabled this extreme elongation, including: absolutely large body size and quadrupedal stance providing a stable platform for a long neck; a small, light head that did not orally process food; cervical vertebrae that were both numerous and individually elongate; an efficient air-sac-based respiratory system; and distinctive cervical architecture. Relevant features of sauropod cervical vertebrae include: pneumatic chambers that enabled the bone to be positioned in a mechanically efficient way within the envelope; and muscular attachments of varying importance to the neural spines, epipophyses and cervical ribs. Other long-necked tetrapods lacked important features of sauropods, preventing the evolution of longer necks: for example, giraffes have relatively small torsos and large, heavy heads, share the usual mammalian constraint of only seven cervical vertebrae, and lack an air-sac system and pneumatic bones. Among non-sauropods, their saurischian relatives the theropod dinosaurs seem to have been best placed to evolve long necks, and indeed their necks probably surpassed those of giraffes. But 150 million years of evolution did not suffice for them to exceed a relatively modest 2.5 m.

Theories of Local Economic Growth (Part 2): Model Specification and Empirical Validation

This study is an attempt to produce a theoretically informed econometric analysis of dynamic regional economic performance. The first paper in this two-part study highlighted the problems and possibilities of translating the propositions contained in six ‘soft’ theories of local economic growth into measurable dimensions and sets of proxy variables that are hypothesized to determine local economic growth. This second paper focuses on issues of econometric-model design and empirical validation. Given the practical limitations imposed by data availability, the ‘soft’ theories of local economic growth are modeled by a simple conditional ‘gap’ convergence model in which prevailing regional unemployment relativities are determined by a common trend in unemployment and a set of regionally specific variables. The empirical validity of the competing ‘soft’ theories of local economic growth is evaluated by applying test restrictions imposed by the ‘soft’ theories to a general model specification containing eight regionally specific variables that have been identified as potential drivers of local economic growth. The econometric modeling of Australian data suggests that the processes of regional economic performance might be somewhat different from those specified in individual theoretical models. Significantly, the role of local ‘enterprise culture’ is revealed—built on specialization, technological leadership, human resources, and the local integration of firms—though significant caveats are attached to the roles of access to information, institutional support, and interregional trade as promoters of local economic growth.

The anatomy and phylogenetic relationships of "Pelorosaurus" becklesii (Neosauropoda, Macronaria) from the Early Cretaceous of England.

The sauropod dinosaur “Pelorosaurus” becklesii was named in 1852 on the basis of an associated left humerus, ulna, radius and skin impression from the Early Cretaceous (Berriasian-Valanginian) Hastings Beds Group, near Hastings, East Sussex, southeast England, United Kingdom. The taxonomy and nomenclature of this specimen have a complex history, but most recent workers have agreed that “P.” becklesii represents a distinct somphospondylan (or at least a titanosauriform) and is potentially the earliest titanosaur body fossil from Europe or even globally. The Hastings specimen is distinct from the approximately contemporaneous Pelorosaurus conybeari from Tilgate Forest, West Sussex. “P.” becklesii can be diagnosed on the basis of five autapomorphies, such as: a prominent anteriorly directed process projecting from the anteromedial corner of the distal humerus; the proximal end of the radius is widest anteroposteriorly along its lateral margin; and the unique combination of a robust ulna and slender radius. The new generic name Haestasaurus is therefore erected for “P.” becklesii. Three revised and six new fore limb characters (e.g. the presence/absence of condyle-like projections on the posterodistal margin of the radius) are discussed and added to three cladistic data sets for Sauropoda. Phylogenetic analysis confirms that Haestasaurus becklesii is a macronarian, but different data sets place this species either as a non-titanosauriform macronarian, or within a derived clade of titanosaurs that includes Malawisaurus and Saltasauridae. This uncertainty is probably caused by several factors, including the incompleteness of the Haestasaurus holotype and rampant homoplasy in fore limb characters. Haestasaurus most probably represents a basal macronarian that independently acquired the robust ulna, enlarged olecranon, and other states that have previously been regarded as synapomorphies of clades within Titanosauria. There is growing evidence that basal macronarian taxa survived into the Early Cretaceous of Europe and North America.

The Effect of Intervertebral Cartilage on Neutral Posture and Range of Motion in the Necks of Sauropod Dinosaurs

The necks of sauropod dinosaurs were a key factor in their evolution. The habitual posture and range of motion of these necks has been controversial, and computer-aided studies have argued for an obligatory sub-horizontal pose. However, such studies are compromised by their failure to take into account the important role of intervertebral cartilage. This cartilage takes very different forms in different animals. Mammals and crocodilians have intervertebral discs, while birds have synovial joints in their necks. The form and thickness of cartilage varies significantly even among closely related taxa. We cannot yet tell whether the neck joints of sauropods more closely resembled those of birds or mammals. Inspection of CT scans showed cartilage:bone ratios of 4.5% for Sauroposeidon and about 20% and 15% for two juvenile Apatosaurus individuals. In extant animals, this ratio varied from 2.59% for the rhea to 24% for a juvenile giraffe. It is not yet possible to disentangle ontogenetic and taxonomic signals, but mammal cartilage is generally three times as thick as that of birds. Our most detailed work, on a turkey, yielded a cartilage:bone ratio of 4.56%. Articular cartilage also added 11% to the length of the turkeys zygapophyseal facets. Simple image manipulation suggests that incorporating 4.56% of neck cartilage into an intervertebral joint of a turkey raises neutral posture by 15°. If this were also true of sauropods, the true neutral pose of the neck would be much higher than has been depicted. An additional 11% of zygapophyseal facet length translates to 11% more range of motion at each joint. More precise quantitative results must await detailed modelling. In summary, including cartilage in our models of sauropod necks shows that they were longer, more elevated and more flexible than previously recognised.

‘Buying’ Power—Interpreting Retail Change in a Circuits of Power Framework

The notion of a new retail geography poses the challenge to produce more critical and rigorous analyses of an important sector of the UK service economy. In this paper we suggest that our understanding of retail processes will be aided by devoting explicit attention to the role of interorganisational power in shaping the commercial environment of the retail sector. Regrettably, many notions of power are undertheorised and static. In particular there is a tendency to treat power as a commodity that may be ‘bought’ rather than as dynamic and relational. We therefore suggest that a modified version of Cleggs model of circuits of power can add a much-needed dynamic element to a new retail geography. The circuits of power framework is applied to a case study from UK food retailing. The approach clarifies the underlying and inherently dynamic processes of power-based inequality that are driving change.

Caudal pneumaticity and pneumatic hiatuses in the sauropod dinosaurs Giraffatitan and Apatosaurus.

Skeletal pneumaticity is found in the presacral vertebrae of most sauropod dinosaurs, but pneumaticity is much less common in the vertebrae of the tail. We describe previously unrecognized pneumatic fossae in the mid-caudal vertebrae of specimens of Giraffatitan and Apatosaurus. In both taxa, the most distal pneumatic vertebrae are separated from other pneumatic vertebrae by sequences of three to seven apneumatic vertebrae. Caudal pneumaticity is not prominent in most individuals of either of these taxa, and its unpredictable development means that it may be more widespread than previously recognised within Sauropoda and elsewhere in Saurischia. The erratic patterns of caudal pneumatization in Giraffatitan and Apatosaurus, including the pneumatic hiatuses, show that pneumatic diverticula were more broadly distributed in the bodies of the living animals than are their traces in the skeleton. Together with recently published evidence of cryptic diverticula—those that leave few or no skeletal traces—in basal sauropodomorphs and in pterosaurs, this is further evidence that pneumatic diverticula were widespread in ornithodirans, both across phylogeny and throughout anatomy.

Power relations and market transformation in the transport sector: the example of the courier services industry

Abstract The courier services industry has developed rapidly in the last three decades. Formed in national niche markets, private sector corporations have grown to challenge one another and now to challenge deregulated state mail monopolies. In this paper we propose a ‘circuits of power’ framework to theorise the diversity, complexity and speed of this change. The framework derives from the work of Clegg (cf. Clegg, S., 1989. Frameworks of Power. Sage, London) and combines different conceptualisations of power to unpack the complex relationships of power and domination that have shaped the sector’s growth.

A New Sauropod Dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA

Brontomerus mcintoshi is a new genus and species of sauropod dinosaur from the Hotel Mesa Quarry in Grand County, Utah, USA, in the upper part of the Ruby Ranch Member (Aptian—Albian) of the Lower Cretaceous Cedar Mountain Formation. It is known from at least two fragmentary specimens of different sizes. The type specimen is OMNH 66430, the left ilium of a juvenile individual; tentatively referred specimens include a crushed presacral centrum, a complete and well-preserved mid-to-posterior caudal vertebra, the partial centrum of a distal caudal vertebra, a complete pneumatic anterior dorsal rib from the right side, the nearly complete left scapula of a much larger, presumably adult, individual, and two partial sternal plates. Brontomerus is diagnosed by five autapomorphies of the type specimen: preacetabular lobe 55% of total ilium length, longer than in any other sauropod; preacetabular lobe directed anterolaterally at 30° to the sagittal, but straight in dorsal view and vertically oriented; postacetabular lobe reduced to near absence; ischiadic peduncle reduced to very low bulge; ilium proportionally taller than in any other sauropod, 52% as high as long. In a phylogenetic analysis, Brontomerus was recovered as a camarasauromorph in all most parsimonious trees, but with uncertain position within that clade. The large preacetabular lobe of the ilium anchored powerful protractor and abductor muscles, but precise interpretation is impossible without functionally related elements such as femora and proximal caudal vertebrae. Brontomerus is the eighth sauropod genus named from the Early Cretaceous of North America, and more remain to be described: North American sauropod diversity did not decline catastrophically at the end of the Jurassic as often assumed. The most striking differences between Late Jurassic and Early Cretaceous sauropod faunas in North America is that the former are abundant and dominated by diplodocids, whereas the latter are comparatively scarce— though still diverse—and dominated by macronarians.