A new late Oligocene to early Miocene species o Apatopygus (Echinoidea: Cassiduloida) from the Maltese Islands

The occurrence of Apatopygus gaudensis sp. nov. in the upper part of the late Oligocene (Chattian) Lower Coralline Limestone division, and the lower part of the early Miocene (probably late Aquitanian) Lower Globigerina Limestone division of the Maltese Islands (Central Mediterranean), is the first confirmed record of Apatopygus outside the Australia-New Zealand region. Apatotygus vincentinus (Tate, 1891) from the middle to late Eocene of southern Australia is the earliest known occurrence of the genus, possibly suggesting that Apatotygus may have evolved earlier in the Australasian region, or merely that it is yet to be discovered in pre-Oligocene strata in the Mediterranean area.     

Sexually dimorphic sea urchins: identifying the sexes in Pentechinus mirabilis

The sexes of most sea urchin species are externally indistinguishable from one another. Where gross sexual dimorphism does exist, it is invariably associated with nonplanktotrophy. In the most extreme examples, female morphology has become modified to create depressions on the test where offspring may be sheltered throughout development. Since a number of the features used for taxonomic classification are lost on fossilization, it can be difficult to recognize fossil individuals as the dimorphic males and females of the same species. In addition, diagnoses of dimorphic taxa commonly concentrate on the striking female traits, hindering identification of the simpler male form. Here, we present an approach based on morphology and crystallographic determination of developmental mode that allows the recognition of the males of marsupiate echinoid taxa. Males of the brooding temnopleurid Pentechinus mirabilis from the Oligocene of Victoria, Australia are described for the first time.     

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.