Hyaline tissue of thermally unaltered conodont elements and the enamel of vertebrates

Comparison of the ultrastructure of the hyaline tissue of conodont elements and the enamel of vertebrates provides little support for a close phylogenetic relationship between conodonts and vertebrates. Transmission and scanning electron microscopy shows that the mineralised component of the hyaline tissue of Panderodus and of Cordylodus elements consists of large, flat, oblong crystals, arranged in layers that run parallel to the long axis of the conodont. Enamel in the dentition of a living vertebrate, the lungfish Neoceratodus forsteri, has crystals of calcium hydroxyapatite, arranged in layers, and extending in groups from the dentine-enamel junction; the crystals are slender, elongate spicules perpendicular to the surface of the tooth plate. Similar crystal arrangements to those of lungfish are found in other vertebrates, but none resembles the organisation of the hyaline tissue of conodont elements. The crystals of hydroxyapatite in conodont hyaline tissue are exceptionally large, perpendicular or parallel to the surface of the element, with no trace of prisms, unlike the protoprismatic radial crystallite enamel of fish teeth and scales, or the highly organised prismatic enamel of mammals.     

New insights into ancient environments using dental characters in Australian Cenozoic lungfish

Environmentally-related wear conditions and pathologies affecting the dentition of fossil lungfish from freshwater deposits in Australia have been analysed and compared with similar changes in the dentition of the living Australian lungfish, Neoceratodus forsten. Fossil populations from the Namba, Etadunna, Wipajiri and Katipiri formations in central Australia, and the Carl Creek Limestone and the Camfield beds in northern Australia were assessed.

Tooth plates from populations of living lungfish from the Brisbane River and Enoggera Reservoir in southeast Queensland were analysed for comparison. Tooth plates were measured to determine the numbers of different age groups in each population. They were assessed for abrasion, attrition, spur and step wear, erosion and caries, and for trauma and pathological conditions such as malocclusion, hyperplasia, abscesses, osteopenia and parasitic damage. AH of these conditions are related to the environment where the fish lived, are found in living members of the group, and can be compared directly with those of fossil relatives.

The results suggest that some of the fossil populations were at risk before climatic changes late in the Cainozoic destroyed their habitats. Some fossil lungfish populations, such as those of the Wipajiri Formation, exhibit active spawning and recruitment, good growth rates and a low incidence of disease and environmentally related damage to the tooth plates. Others, like those of the Katipiri and Namba Formations, include no young, and the adult fish were ageing and show environmentally-related damage to the dentition. Etadunna lungfish had active recruitment, but the tooth plates show a high incidence of attrition and caries. Riversleigh lungfish were actively spawning but did not grow large. Tooth plates from this latter deposit have a high incidence of pathological conditions. Fish from the Camfield Beds, where food was severely limiting, had little serious pathology but high levels of caries. Pathologies among living lungfish are common, but fossil fish were comparatively healthy, with few serious dental problems. Information from studies of fossil lungfish confirms that conservation of the few living species of lungfish depends on the maintenance of clean environments that provide adequate supplies of food and suitable sites for spawning and for the growth of young fish.     

First record of Carinodens (Squamata,Mosasauridae) from the uppermost Maastrichtian of Stevns Klint,Denmark

Milàn, J., Jagt, J.W.M., Lindgren, J. & Schulp, A.S., November 2017. First record of Carinodens (Squamata, Mosasauridae) from the uppermost Maastrichtian of Stevns Klint, Denmark. Alcheringa 42, 597-602. ISSN 0311-5518.

Here we report on an important addition to the Late Cretaceous fossil record of marine reptiles from Denmark: a tooth crown of the rare durophagous mosasaur Carinodens minalmamar found in the uppermost Maastrichtian strata at the UNESCO World Heritage Site Stevns Klint. The tooth was found within the uppermost few metres of the Maastrichtian chalk placing it within the latest 50.000 years prior to the K/Pg boundary. The new find is a shed crown probably representing a tooth from the 11th to 13th position in the jaw. The tooth represents the northernmost occurrence of the genus Carinodens. Previous mosasaur finds from Denmark have all been from the hypercarnivorous mosasaurids Mosasaurus hoffmannii and Plioplatecarpus sp., thus our specimen adds a new trophic niche exploited by marine tetrapods in the food web of the latest Maastrichtian of Denmark.

Jesper Milàn* [jesperm@oesm.dk], Geomuseum Faxe/Østsjællands Museum, Østervej 2, 4640 Faxe, Denmark; John W.M. Jagt [john.jagt@maastricht.nl], Natuurhistorisch Museum Maastricht, De Bosquetplein 6–7, 6211 kJ Maastricht, the Netherlands; Johan Lindgren [johan.lindgren@geol.lu.se], Department of Geology, Lund University, Sölvegatan 12, 223 62 Lund, Sweden. Anne S. Schulp? [anne.schulp@naturalis.nl], Natuurhistorisch Museum Maastricht, De Bosquetplein 6–7, 6211 kJ Maastricht, the Netherlands. *Also affiliated with: Natural History Museum of Denmark, Øster Voldgade 5–7, 1465 Copenhagen K, Denmark. ?Also affiliated with: Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, the Netherlands, and Faculteit Bètawetenschappen, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands.     

Women,Nation and Decolonisation in Papua New Guinea

This paper explores the question of women, decolonisation and nation-building. It argues that the inclusion of women within the nation of Papua New Guinea (PNG) was problematic partly because women had rarely experienced mainstream colonial rule — an experience that elsewhere provided a basis for participation in the post-colonial state. The paper also investigates how women were perceived and represented by male writers at independence. While the Pangu Pati attempted to include women in state-building, these efforts were not adequately supported. PNG's achievement of independence coincided with the globalisation of second-wave feminism, and this was to prove critical for PNG's female citizens in their efforts to be included in the new state, for PNG's membership in the United Nations provided an external push to raise women's participation in the nation. Nevertheless, the government's dependence on international organisations to push the women's agenda also hampered the development of an autonomous women's movement in the country. The paper argues that, for PNG's female citizens, colonisation, independence and decolonisation occurred simultaneously after 1975.