Heterogeneity of birth-state effects on internal migration

Working in a discrete location choice framework, we develop a model of migration that allows the identification of heterogeneity in state-of-birth effects across states. We employ a novel method for using aggregate data to estimate the role of birth state on migration choices. This approach reveals considerable heterogeneity and some regional clustering in birth-state inertia effects across states, with strong attachments in California, the Southwest, and the upper Midwest. The weakest attachments are in the mountain states and New York.     

A review of the taxonomy and systematics of the echinoid genus Monostychia Laube, 1869

Sadler, T., Kroh, A. &; Gallagher, S.J., March 2016. A review of the taxonomy and systematics of the echinoid genus Monostychia Laube, 1869 Laube, G.C., 1869. Über einige fossile Echiniden von den Murray Cliffs in Süd-Australien. Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften zu Wien, mathematisch-naturwissenschaftliche Classe. Abtheilung I 59, 183–198. [Google Scholar]. Alcheringa 40, xxx–xxx. ISSN 0311-5518

A review of Monostychia, a stratigraphically important clypeasteroid echinoid genus in southern Australian Oligocene/Miocene strata, reveals uncertainty in relation to morphological features used in taxonomy. The result is that the exact systematic position of the genus remains unresolved at subfamily level. Monostychia and its type species, M. australis, are redescribed. Monostychia australis is restricted to the lower to middle Miocene Glenforslan Formation of the Murray Basin. Three other species currently within Monostychia, M. etheridgei, M. loveni and M. elongata, are discussed. Although it is concluded that M. etheridgei belongs in the genus and is a distinct species, the taxonomic position of M. loveni is questioned, and the validity of M. elongata as a separate species from M. australis remains uncertain. This work lays the foundation for further revisions of Monostychia with an expectation that such work will provide the basis for character determination that may be useful across other echinoid taxa.

Tony Sadler [t.sadler@uq.edu.au] and Stephen J. Gallagher [sjgall@unimelb.edu.au], School of Earth Sciences, University of Melbourne, Victoria 3010, Australia; Andreas Kroh [andreas.kroh@nhm-wien.ac.at], Natural History Museum Vienna, Department of Geology and Palaeontology, Burging 7, 1010, Vienna, Austria.