Permian brachiopoda from China and Malaysia : palaeoecology, palaeobiogeography and extinctions

The systematics, palaeoecology, palaeobiogeography and patterns of faunal change of Permian brachiopods from Sichuan, China and Pahang, Malaysia were investigated. The brachiopods from Pahang were systematically described for the first time. Five new species and one new genus were found in Sichuan, and two extinction and five origination events were recognised.

Systematics and palaeoecology of Changhsingian (Late Permian) Ambocoeliidae brachiopods from South China and implications for the end-Permian mass extinction

Four Ambocoeliidae brachiopod species including one new species (Crurithyris tazawai sp. nov., Crurithyris sp., Paracrurithyris pygmaea and Attenuatella mengi) are described from the Changhsingian (Late Permian) deep-water facies of South China. Analysis of the morphology, palaeoecology and palaeogeographical and temporal distributions of these species revealed that the presence of a delthyrium and/or the micro-ornaments among three of the four species (Crurithyris tazawai sp. nov., Paracrurithyris pygmaea and Attenuatella mengi) favoured an epifaunal (epiphytic) lifestyle. Morphological differences suggest that Paracrurithyris pygmaea may have been more effective metabolically in forming the shell compared with Attenuatella mengi and Crurithyris tazawai. The temporal and palaeogeographical distribution of Attenuatella suggests that A. mengi inhabited cool or cold deep waters. Both Crurithyris tazawai and Attenuatella mengi disappeared earlier in the stratigraphic record than Paracrurithyis pygmaea during the Permian–Triassic mass extinction. These differences in timing of extinction, morphology and palaeogeographical distributions suggest that oxygen deficiency and trophic resource limitation (a consequence of the changing composition of marine phytoplankton in the seas) may have contributed to the end-Permian mass extinction.

Neohornibrookella sorrentae (Chapman and Crespin, 1928) and allied ostracod taxa from the Neogene of southeastern Australia: systematic and palaeoceanographical relationships, palaeoecology and palaeobiogeography

Three closely allied shallow marine taxa, Neohornibrookella sorrentae (Chapman and Crespin), Neohornibrookella glyphica (Neil), and Neohornibrookella nepeani sp. nov. are recorded from latest early Miocene to late Pliocene strata in southeastern Australia. These taxa, together with Neohornibrookella quadranodosa (Holden) from the Miocene of Midway Island (Northwestern Hawaiian Islands), form a morphologically distinct group of relatively large species (the sorrentae-group) within the genus Neohornibrookella Jellinek. Latitudinal expansion of the subtropical and warm-temperate climatic belts together with the influence of warm western boundary surface currents associated with the North and South Pacific gyres, are likely to have played key roles in the Miocene dispersal of this species group. Species of the sorrentae-group first migrated south from equatorial west Pacific regions into southeastern Australia during the early Miocene, under the influence of the East Australian Current. During three time intervals (i) latest early Miocene, (ii) latest late Miocene and (iii) earliest late Pliocene, forceful pulses of the East Australian Current played a significant role in propelling the widespread distribution of thermophilic Neohornibrookella species across southeast Australian shallow marine realms. During intervening middle and late Miocene times, Neohornibrookella species are only sporadically present across the Bass Strait region of southeast Australia, indicating a weaker East Australian Current influence and the cooling influence of coastal upwelling. During the mid early Pliocene Neohornibrookella species disappeared from the western Bass Strait region, suggesting the complete exclusion of East Australian Current waters from this region. This was probably due to the counteracting influence of the eastward flowing Zeehan Current (extension of the Leeuwin Current) impinging on the western Bass Strait region. This mid early Pliocene palaeobiogeographical partition in Bass Strait, defined by the distribution of sorrentae-group species, is here termed the Bassian Gateway. The two species, N. sorrentae and N. glyphica, occur concurrently during the mid Miocene in southeast Australia, but are associated with different lithofacies. It is hypothesised that there is a heterochronic evolutionary relationship expressed in the ornament of these two species. The thaerocytherid genera Neohornibrookella Jellinek, Tenedocythere Sissingh and Bosasella Bonaduce are here included in the new ostracod subfamily Tenedocytherinae.

Permian brachiopods from the Selong Xishan section, Xizang (Tibet), China. Part 2: palaeobiogeographical and palaeoecological implications, spiriferida, athyridida and terebratulida

Brachiopods from the Selong Group at the Selong Xishan section indicate a typical Peri-Gondwanan affinity, but possibly a rapid invasion of tropical/subtropical Tethyan elements into the Himalayan region at the very end of Permian. A brief analysis of taphonomy and composition of the Selong fauna indicate that Selong Xishan lay on the shallow continental shelf near shore and brachiopods suffered substantial abrasion from contemporaneous wave action. Species of Spiriferida, Athyridida and Terebratulida are herein described and revised. New taxa are Nakmusiella selongensis nov. gen. et sp. and ? Bullarina striata nov. sp.

Guadalupian (Middle Permian) brachiopods from Sungai Toh, a Leptodus Shale locality in the Central Belt of Peninsular Malaysia. Part I: Lower Horizons

This work presents a systematic study of Permian Brachiopoda from the Sungai Toh Leptodus Shale locality, Pahang State, Peninsular Malaysia. This locality lies within the Central Belt of Peninsular Malaysia, a tectonic unit characterised.by tuffaceous sediments and limestones of Late Palaeozoic age. Two brachiopod-bearing horizons were studied in detail at this locality, the lower one (Horizon 2) bearing a mixed plant and invertebrate assemblage, including the brachiopods Urushtenoidea chaoi (CHING), Leptodus richthofeni KAYSER, Anidanthus cf. sinosus HUANG, Acosarina dorashamensis (SOKOLSKAJA), A. minuta (ABleH) and unidentifiable species of Linoproduetus, Neochonetes, and Strophalosiina. Horizon 3 contains a more abundant and diverse brachiopod fauna, comprising a total. of 57 species representing 47 genera, including Vediproductus punetatiformis (CHAO), Permianella typica HE & ZHU, Tranrennatia gratiosa (WAAGEN), Leptodus richthofeni KAYSER, Leptodus cf. tenuis (WAAGEN) and "Semibrachythyrina" [= Alphaneospirifer] cf. pyramidiformis LIANG. It is
suggested in this study that the age of the Sungai Toh locality is Capitanian (late Guadalupian) to possibly Wuchiapingian (early Lopingian),
as it appears to correlate well with the Lengwu fauna from Zhejiang in eastern China. The palaeobiogeographical affinities of the Sungai Toh fauna are interesting, mainly indicating strong Palaeo-equatorial affinities, while there are also some elements more typical of the cooler periGondwana
Region.

Quaternary beetles : a review and issues for Australian studies

Few Australian entomologists, ecologists, biogeographers or Quaternary researchers are familiar with the details of Quaternary beetle research. Since the 1950s the study of fossil beetles has developed to become an important discipline of the Quaternary sciences. Unfortunately, however, the significance of the discipline for ecological and evolutionary research has been slow to penetrate mainstream entomological, ecological, and evolutionary thought. This paper outlines the history, methods and results of Quaternary beetle studies, based primarily upon research from the well-studied Northern Hemisphere, and then examines issues relevant to Australian research. Analysis of Quaternary beetle assemblages from Australia can contribute to the reconstruction of past environments and climates, in particular quantitative estimation of past temperature regimes, and potentially, effective precipitation. Of more significance to entomology, however, is the potential to reconstruct climatically-induced changes in distribution, essential for understanding the Quaternary biogeographic history of Australia's insect fauna. Furthermore, it will be possible to examine evidence, or the lack thereof, for speciation during the Quaternary, in the context of Quaternary environmental change.

Mid-Holocene (4200 kyr BP) mass mortalities in Mauritius (Mascarenes): insular vertebrates resilient to climatic extremes but vulnerable to human impact

In the light of the currently increasing drought frequency and water scarcity on oceanic islands, it is crucial for the conservation of threatened insular vertebrates to assess how they will be affected. A 4000 yr old fossil assemblage in the Mare Aux Songes (MAS), southwest Mauritius, Mascarene Islands, contains bones of 100 000+ individual vertebrates, dominated by two species of giant tortoises Cylindraspis triserrata and C. inepta, the dodo Raphus cucullatus, and 20 other vertebrate species (Rijsdijk, Hume, Bunnik, Florens, Baider, Shapiro et al. (2009) Mid-Holocene vertebrate bone Concentration-Lagerstätte on oceanic island Mauritius provides a window into the ecosystem of the dodo (Raphus cucullatus). Quaternary Science Reviews 28: 14–24). Nine radiocarbon dates of bones statistically overlap and suggest mass mortality occurred between 4235 and 4100 cal. yr BP. The mortality period coincides with a widely recognized megadrought event. Our multidisciplinary investigations combining geological, paleontological and hydrological evidence suggests the lake was located in a dry coastal setting and had desiccated during this period. Oxygen isotope data from a Uranium-series dated stalagmite from Rodrigues, an island 560 km east of Mauritius, supports this scenario by showing frequently alternating dry and wet periods lasting for decades between 4122 and 2260 cal. yr BP. An extreme drought resulted in falling water-tables at MAS and elsewhere on the island, perhaps deprived these insular vertebrates of fresh water, which led to natural mass mortalities and possibly to extirpations. In spite of these events, all insular species survived until at least the seventeenth century, confirming their resistance to climatic extremes. Despite this, the generally exponential increase of combined human impacts on islands including loss of geodiversity, habitats, and stocks of fresh water, there will be less environmental safe-haven options for insular endemic and native vertebrates during future megadrought conditions; and therefore will be more prone to extinction.

Description of systenobythere gen. nov. (Ostracoda, Crustacea) from the late miocene of southeastern Australia with comments on its problematical taxonomic and palaeoecological affinities

A new ostracod genus and species, Systenobythere archboldi, is described from late Miocene open neritic strata of southeastern Australia. Specimens occur in argillaceous glauconitic sands deposited in offshore continental shelf settings that were periodically influenced by coastal upwelling. Systenobythere archboldi possesses an adductor muscle scar pattern typical of the Bythocytheridae, but has a pentodont hinge and sieve-type normal pore canals atypical of this family.

Preservation and assemblage characteristics of some ornate Lower Devonian Ostracoda from the Humevale Siltstone and Woori Yallock Formation, southeastern Australia

.The Humevale Siltstone (late Silurian to Early Devonian, Gorstian to Pragian) and Woori Yallock Formation (Early Devonian, Emsian) of central Victoria, Australia, contain rich invertebrate fossil faunas including Ostracoda. Eight ostracod taxa are recognized and illustrated herein: Velibeyrichia wooriyallockensis (Chapman), Velibeyrichia (s.l.) australiae (Chapman), Velibeyrichia sp. 1, Velibeyrichia sp. 2, Beyrichia? ligatura (Chapman), Ulrichia sp., Euglyphella sp. and Strepulites sp. The ostracods are preserved in siltstones and mudstones as natural moulds. Ostracod assemblages are mainly shallow marine and likely include moderate- to low-energy biocoenoses, pseudo-biocoenoses (gravity flow accumulations) and thanatocoenoses.