Smith, A. B. & Rader, W. L. (2009). Echinoid diversity, preservation potential and sequence stratigraphical cycles in the Glen Rose Formation (early Albian, Early Cretaceous), Texas, USA. Palaeobiodiversity and Palaeoenvironments. 89: 7–52.
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Smith, A. B. & Rader, W. L.
2009
Echinoid diversity, preservation potential and sequence stratigraphical cycles in the Glen Rose Formation (early Albian, Early Cretaceous), Texas, USA
Palaeobiodiversity and Palaeoenvironments
89: 7–52
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The correlation between echinoid species diversity and second- and third-order sequence stratigraphical cycles is investigated in the Lower Cretaceous carbonate platform sequences of central Texas. Echinoid faunas from the early Albian Glen Rose Formation have been collected and placed into a sequence stratigraphical framework for the region. There are three discrete communities, each characterising a different part of a second order transgression–regression cycle within the Coahuila Group. A perireefal community is found in the Transgressive Systems Tracts (TST) characterised by Pygopyrina, Balanocidaris, Hyposalenia and Pseudodiadema, an open shelf levelbottom community of spatangoids and saleniids is developed at the Maximum Fooding Surface, and a more coastal
algal meadow community characterized by Loriolia is preserved in small flooding events in the Highstand Systems Tracts. Beds yielding echinoid faunas are restricted to early TST stages of small-scale cycles within the Glen Rose Formation. This, we argue, reflects changing preservation potential, with echinoid tests only entering the fossil record during periods when accommodation space on the carbonate platform temporarily increased, promoting sediment accumulation rates to rise. The following new taxa are recognized: Parorthopsis gen. nov., Goniopygus whitneyi sp. nov., Tetragramma tenerum sp. nov., Polydiadema travisensis sp. nov., Codiopsis (Hemicodiopsis) pulchella sp. nov. and Plagiochasma texanum sp. nov.
Keywords Taxonomy. Sequence stratigraphy . Diversity. Cretaceous