Bite marks on an ichthyodectiform fish from Australia: possible evidence of trophic interaction in an Early Cretaceous marine ecosystem

Wretman, L. & Kear, B.P., 2013. Bite marks on an ichthyodectiform fish from Australia: possible evidence of trophic interaction in an Early Cretaceous marine ecosystem. Alcheringa 38, 000–000. ISSN 0311-5518.

A well-preserved fish skull from late Albian deposits of the Allaru Mudstone near Richmond in Queensland displays a conspicuous V-shaped pattern of indentations, punctures and depression fractures consistent with a vertebrate bite trace. This is the first direct evidence of trophic interaction between vertebrates within an Early Cretaceous marine ecosystem from Australia. The specimen is taxonomically referable to the large-bodied (ca 1?m snout–tail length) ichthyodectiform Cooyoo australis, but the size and spacing of the tooth marks is incompatible with attack by a conspecific individual. The lack of osseous growths concordant with healing also suggests that the bite occurred shortly before or after the animal’s death. Comparison with the dentitions of other coeval vertebrates indicates compatible tooth arrangements in longirostrine amniote predators such as polycotylid plesiosaurians, ornithocheiroid pterosaurs and especially the ichthyosaurian Platypterygius. The implications of this as a potential predator–prey association are that Early Cretaceous actinopterygians occupied middle-level trophic niches and were in turn consumed by higher-level amniote carnivores, similar to many extant marine vertebrate communities of today.

Lovisa Wretman [lovisa.wretman@ebc.uu.se], Subdepartment of Evolution and Development, Department of Organismal Biology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden (address for correspondence); Benjamin P. Kear [benjamin.kear@geo.uu.se], Palaeobiology Programme, Department of Earth Sciences, Uppsala University, Villavägen 16, SE-752 36 Uppsala, Sweden. Received 8.8.2013, revised 17.9.2013, accepted 23.9.2013.     

POOR MEN: ON THE MASCULINIZATION OF POVERTY IN SWEDEN, 1957–1981

This paper discusses the underlying causes behind the masculinization of poverty during the period of 1957–1981 in Sweden. Testable hypotheses are derived from a theoretical framework. The findings suggest that the male role as breadwinner disappeared during the analysed period. Lowly educated men and especially male immigrant labour lost their labour market position when industrial society gave way to a new post-industrial society, with an expanding service sector bringing numerous new employment opportunities for women. When sick or unemployed, social assistance was the only social security these men had available. On the other hand, the welfare-state expansion targeted women, particularly single mothers and widows, and thus reduced the number of native women claiming social assistance. The findings also point to the process character of the masculinization of poverty, arguing that women gained significantly more than men from the expansion of the welfare state.