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.     

Geographical Influences on Settlement-Location Choices by Initial Colonizers: a Case Study of the Fiji Islands

From 3200 to 2850 cal BP (1250–900 BCE), the Lapita people of the Bismarck Archipelago (Papua New Guinea) undertook voyages eastward that led to their colonization of the eastern outer Solomon Islands, Vanuatu, New Caledonia, Fiji, Tonga and Samoa. The earliest (Lapita) settlements in Fiji were along the Rove Peninsula in southwest Viti Levu Island. At the time of colonization, sea level was 1.5 m higher than today. The Rove Peninsula was then a smaller island off the coast of larger Viti Levu, with a broad, fringing reef along its windward coasts, which was probably the main attraction for Lapita colonizers. As elsewhere during Lapita times in the western tropical Pacific Islands, settlement choice for the initial colonizers of the Fiji Islands was at one level driven by site access, at another by the presence of broad, fringing coral reefs suitable for marine foraging. The earliest settlement along the Rove Peninsula was at Bourewa, occupied first in 3050 cal BP (1100 BCE), where people lived in houses on stilt platforms built along the axis of a subtidal sand barrier; on one side was a broad coral reef, on the other a partly-enclosed tidal inlet. There is no evidence that the Bourewa settlers practised horticulture or agriculture at this time, their subsistence being predominantly marine foraging. After some 300 years of following this subsistence strategy, the inhabitants of Bourewa responded to sea-level fall and the arrival of cultivars (of taro and yam) by including horticulture. As sea level fell further, a total of 550 mm during the Lapita era, the tidal inlet dried up and marine-food resources diminished to a point where the natural environment of the Rove Peninsula could no longer sustain its Lapita inhabitants. All Lapita sites in the area were abandoned about 2500 cal BP (550 BCE), at the same time as the Lapita culture, marked by the end of dentate-pottery manufacture, came to an end in Fiji.