First record of the ichthyodectiform fish Xiphactinus (Teleostei) from Patagonia,Argentina

Abstract

We report the first record of the genus Xiphactinus from southern South America. The recovered fossil material consists of an associated maxilla and abdominal vertebra, probably derived from latest Maastrichtian marine deposits of the Salamanca Formation in Chubut Province, Argentina. Xiphactinus has been widely reported from Late Cretaceous strata throughout the Northern Hemisphere, although to date, equivalent Southern Hemisphere occurrences include only a single specimen from Venezuela. Our new discovery thus indicates that Xiphactinus had a much more cosmopolitan distribution, encompassing the southern paleolatitudinal extremities of South America during the terminal Cretaceous.

Julieta J. De Pasqua [julietadepasqua@gmail.com], Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’, Av. Ángel Gallardo, 470, C1405DJR, Buenos Aires, Argentina;

Federico L. Agnolin [fedeagnolin@yahoo.com.ar], Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’, Av. Ángel Gallardo, 470, C1405DJR, Buenos Aires, Argentina. CONICET; Fundación de Historia Natural ‘Félix de Azara’, Departamento de Ciencias Naturales y Antropología, Universidad Maimónides; Hidalgo 775 piso 7, C1405BDB, Buenos Aires, Argentina;

Sergio Bogan [sergiobogan@yahoo.com.ar], Fundación de Historia Natural ‘Félix de Azara’, Departamento de Ciencias Naturales y Antropología, Universidad Maimónides; Hidalgo 775 piso 7, C1405BDB, Buenos Aires, Argentina.     

Canada–Mexico Relations: Interdependence,Shared Values … and the Limits of Cooperation

This article offers a historical overview of the evolution of the relationship between Canada and Mexico, emphasizing its exiguity, its fundamental economic nature and the consequences of sharing borders with the United States. It is organized as follows: the first section covers the period going from the establishment of diplomatic relations in 1944 to the late 1960s, a period during which the bilateral relation failed to consolidate despite sporadic efforts; the second section deals with the period starting with the convergence of political visions in the two capitals in the early 1970s up to the period immediately preceding the starting of the negotiations leading to NAFTA. The period during which the most significant engagement between the two countries has taken place to the present is reviewed in the third section. The article concludes presenting some thoughts on the possibilities and limits of cooperation between the two countries.     

Post/neo/liberalism in relational perspective

Within a decade of the new millennium new left governments in many countries across Latin America developed new constitutions that bespeak a new, postneoliberal era, supplanting neoliberal hegemony. Debates about postneoliberalism-as-governance or as a discourse lack resolution. Drawing from Foucault's lecture series The Birth of Biopolitics, which engages the relation between neoliberalism and liberalism, as well as from his general analytic approach, we cast postneoliberalism, neoliberalism, and liberalism in relational terms relative to principles not time periods, and offer precision on how different discourses co-exist and become mutually entangled and politicized in the context of neoliberal practices. We reference points in our argument with empirical research in various Latin American contexts, and in the penultimate section we thread the argument through current dynamics in one context, Nicaragua. Although overall we concur with the critical literature about the neoliberal character of pink-tide governments in practice, in the final section we depart from the prevailing approach that focuses on formal government as the bellwether of change and conclude by drawing attention to prospects for postneoliberal practices in the microspaces of daily life. Drawing from Foucault's late scholarship on ethics and mindful of the longstanding role of informality in Latin American political economy, we clarify how postneoliberal values can materialize in everyday life while formal governmental actions and policies persist as neoliberal amid liberal, postneoliberal, as well as socialist discourses.     

Canada-US Relations: No Longer Special or Privileged

ABSTRACT

Canada has benefited more than most countries from the advantage of its geography, but proximity to the United States has created a cocoon of complacency on trade and security that is no longer assured. This makes the key question about the future of Canada-US relations whether the erratic “America First” impulses of Donald Trump will persist after he leaves the White House. If nationalist populism takes root, self-interest will prevail and the special partnership for Canada with the United States will fade. This essay considers the notion of privilege that served Canada well for decades as one that can no longer be taken for granted. Canada must take realistic actions to defend and advance its own interests. This will reflect the confidence and maturity of a nation fully aware of its capabilities and the limitations of its global potential.     

Cambrian Hyolitha of Siberian,Baltican and Avalonian aspect in east Laurentian North America: taxonomy and palaeobiogeography

Malinky, J.M. & Geyer, G., 6 March 2019. Cambrian Hyolitha of Siberian, Baltican and Avalonian aspect in east Laurentian North America: taxonomy and palaeobiogeography. Alcheringa 43, 171–203. ISSN 0311-5518.

Newly identified hyoliths from early Cambrian ‘Small Shelly Fossil’ assemblages in New York State and Quebec extend the geographical ranges of hyolith taxa, otherwise known only from Baltica and Siberia, into eastern Laurentian North America, and in some cases, are accompanied by significant stratigraphical range extensions. The newly recognized taxa from this region include the hyolithids Hexitheca washingtonensis sp. nov., Aimitus sp., A. sp. cf. A. communis, Anabaricornus sp., Similotheca americana, Grantitheca glenisteri, and the orthothecids Decoritheca sp., Contitheca sp., two species of Holmitheca, and two hyolith species that can not be confidently assigned to an order at this time. Early Cambrian limestone clasts within the Lower Ordovician of Quebec have produced the hyolithids Similotheca americana and Nevadotheca princeps. The occurrences of Aimitus, Anabaricornus, and Holmitheca provide a palaeobiogeographical link with hyolith assemblages in Siberia, and Hexitheca to Baltica. Contitheca not only is known from these areas, but also has been found in west Laurentia, Morocco, Korea and Antarctica. A review of previously named species demonstrates that none of their type materials can be confidently referred to genus or species level because of poor preservation.

John M. Malinky [jmalinky@sbcglobal.net], Department of Physical Science, San Diego City College, 1313 Park Boulevard, San Diego, CA 92101, USA; Gerd Geyer* [gerd.geyer@uni-wuerzburg.de], Institut für Geographie und Geologie, Bayerische Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.     

Teeth of juvenile woodchucks as seasonal indicators on archaeological sites

The woodchuck, Marmota monax, a burrowing scuirid of eastern North America, was a common food animal of prehistoric peoples. Since the species has a single, brief birthing period all juveniles are at a comparable stage of development at a given time. Widths of the continuously growing incisors, development of the cheek teeth and alveoli, and loss of deciduous teeth have been determined from a sample with known dates of collection. These data are compared to juvenile woodchuck remains from an archaeological site to determine season of kill.     

Reconstructing age distribution,season of capture and growth rate of fish from archaeological sites based on otoliths and vertebrae

The growth increments of otoliths and vertebrae of plaice (Pleuronectes platessa) derived from a 15th century single depositional event at Raversijde (Belgium) are analysed with the aim of reconstructing (a) the age distribution of the population, (b) the season of capture, and (c) the growth rate. Otoliths and vertebrae give slightly different age distributions but it is possible to arrive at similar seasonality estimations in both structures when information from the literature and our own data from monthly captures of plaice from the North Sea are taken into account. These modern data show that the timing of annulus formation in otoliths and vertebrae is more or less similar. Back‐calculations on vertebrae and otoliths yield similar growth curves. The age distribution, the edge condition of both vertebrae and otoliths, and the growth rate obtained on the material from Raversijde all show that the plaice from the studied assemblage were captured during spring in the southern part of the North Sea. Vertebrae are commonly preserved in archaeological sites whereas otoliths rarely survive. Although they are more difficult to read than otoliths, vertebrae of plaice can be used for growth increment analyses, and the growth rates obtained from vertebrae from archaeological sites can, therefore, be compared in the future to growth data from modern otoliths studied in sea fisheries research. Archaeozoological material predating industrialized fishing since the 19th century can hence serve as a reference in the study of the compensatory response of commercially important species to heavy exploitation. Copyright © 1999 John Wiley & Sons, Ltd.     

Hydraulic engineering and irrigation agriculture in the Moche Valley,Peru: c. A.D. 1250–1532

This paper examines the hydraulic properties (i.e. velocity and discharge) of the main late prehistoric canals of the Moche Valley. Velocities, estimated from excavated canal sections using the Manning flow equation, are compared to tables of maximum permissible velocities and reveal that canals were constructed to transport water efficiently, but that on gradients steeper than 1:100 the Chimu and Inca engineers were unable to transport large discharges without severe erosional problems. Discharge estimates are compared with modern field requirements, using a known ethnographic watering cycle. This demonstrates that in almost every instance the channel size was of the same order of magnitude as that predicted from the requirements. The construction of the Inter-valley canal to bring water to the state lands in Moche was a technological disaster.