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demersal taxa

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Journal Article
Journal: PALAIOS
Published: 01 August 2012
PALAIOS (2012) 27 (8): 585-593.
... the stage, however. Successive bulk samples from the Lombardian Alps, Italy, reveal gradual changes in dominant taxa throughout the Norian, and paleoecological transitions consistent with the Mesozoic Marine Revolution (MMR) hypothesis. At the expense of stationary epifauna, mobile infauna diversified...
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Journal Article
Journal: PALAIOS
Published: 01 March 2011
PALAIOS (2011) 26 (3): 160-172.
..., the largest part of the assemblage is represented by benthic and demersal taxa primarily inhabiting sandy and well-oxygenated substrates; however, the presence of the speckled bearded cusk-eel Brotula cf. ordwayi seems to indicate the existence of rocky reefs in the surroundings of the depositional...
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Journal Article
Journal: PALAIOS
Published: 01 April 2016
PALAIOS (2016) 31 (4): 122-124.
... adaptive radiations appear to be synchronous with an increase in demersal durophages, which would have roamed the seafloor in search of prey. In the Late Triassic, both infaunal and mobile invertebrates increased relative to epifaunal and immobile taxa, respectively ( Tackett and Bottjer 2012 ; this issue...
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Journal Article
Journal: Paleobiology
Published: 01 June 2012
Paleobiology (2012) 38 (3): 424-446.
... is in the field between planorbicones and platycones, in the shape space for which the demersal life mode is one hypothesis. Morphospace nearest the top leg of the triangle is the least occupied. This area corresponds to very low whorl expansion values. Because we calculated whorl expansion with shell radii...
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Journal Article
Published: 04 May 2010
Geological Magazine (2010) 147 (6): 860-870.
... towards the Atlantic coast are obviously linked to the high sea-level sequences (e.g. Miller et al . 2005 ) and a lack of barrier during this period (Meulenkamp & Sissingh, 2003 ; Guiraud et al . 2005 ). However, the remarkable similarity of tropical and demersal taxa (e.g. Pristidae...
Journal Article
Journal: Paleobiology
Published: 01 November 2010
Paleobiology (2010) 36 (4): 534-554.
... representatives of these genera, and selected brackish and marine corbulid genera. A species-level analysis added all described freshwater corbulid taxa to the genus-level matrix. Our results were highly resolved (few most-parsimonious trees), but not particularly robust (low branch support). For the genus-level...
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Journal Article
Journal: Paleobiology
Published: 27 April 2015
Paleobiology (2015) 41 (3): 387-401.
... of male and females vanish as population size approaches carrying capacity (Drago et al. 2009 , 2010 ). Likewise, the pelagic diet of South American sea lions prior to exploitation by western sealers (this study) suggests that the current resource partitioning between demersal...
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Journal Article
Journal: PALAIOS
Published: 01 April 2016
PALAIOS (2016) 31 (4): 190-202.
... ( Harper 1991 ; Hautmann 2004 ; Tackett and Bottjer 2012 ), and resurgent taxa of the so-called Paleozoic Fauna were replaced by Modern Fauna constituents ( Greene et al. 2011 ). Most of the Late Triassic and nearly half of the entire Triassic Period is comprised of the Norian Stage, recently determined...
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Journal Article
Published: 01 September 2013
Journal of Paleontology (2013) 87 (5): 755-774.
... to a purported connection between the Pacific and Atlantic (Caribbean) oceans. However, the diverse chondrichthyan fauna has been poorly documented. Based on recent field discoveries and further analysis of existing collections, the chondrichthyan fauna from this unit comprises at least 26 taxa, of which four...
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Journal Article
Journal: PALAIOS
Published: 01 January 2013
PALAIOS (2013) 28 (1): 9-22.
... in abundance and diameter of this ammonite appear to be related to changes of oxygen content in the water column. P. flexuosum dwelled in the well-oxygenated upper surface water and formed part of the open marine pelagic ecosystem; a demersal mode of life is excluded here. Dimorphism is expressed in size...
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Journal Article
Journal: Geology
Published: 01 December 2005
Geology (2005) 33 (12): 929-932.
... ( Emlet et al., 1987 ; Emlet, 1994 ). Thus, although the loss of planktotrophy results in decreased fecundity, there is also the potential decrease in egg mortality, given that it does not encounter the benthos until it has developed into a juvenile. Several other taxa have evolved unique solutions...
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Series: Geological Society, London, Memoirs
Published: 01 January 2013
DOI: 10.1144/M38.28
EISBN: 9781862396425
... is Early Cambrian in age. The first taxa with mineralized exoskeletons are at least Ordovician in age, followed by a sporadic fossil record with Talimaa’s Gap of c. 3 myr in the Rhuddanian (earliest Silurian). Ordovician and Silurian vertebrate faunas are dominated by ‘agnathans’. Early Palaeozoic...
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Journal Article
Journal: PALAIOS
Published: 01 April 2005
PALAIOS (2005) 20 (2): 121-141.
... disparity. Twenty ammonoid genera are recognized and assigned to seven morphostructural groups. The aims of this study are to: (1) interpret abundance variations of ammonoid taxa in terms of taphonomic processes, sedimentary dilution, and paleoenvironmental factors; and (2) discuss the habitat and mode...
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Journal Article
Published: 09 September 2016
Journal of the Geological Society (2016) 174 (1): 18-22.
... Hill biota, comprising some 31 taxa, includes benthic and demersal components ( Fig. 3 ): medusae, lingulid brachiopods and chasmataspidid arthropods are the most common elements. Macroalgae ( Fig. 3a and b ) are moderately abundant and include a tuft-like form and two species of dasycladalean green...
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Journal Article
Journal: PALAIOS
Published: 01 September 2012
PALAIOS (2012) 27 (9): 617-626.
... gravesianus, Sciponoceras glaessneri, and Turrilites costatus. The latter three taxa are heteromorphic ammonites. Hypoturrilites gravesianus and Turrilites costatus are helically coiled, whereas Sciponoceras glaessneri has a straight (orthoconic), tapering conical shell consisting of a thick, outer nacreous...
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Journal Article
Published: 01 March 2010
Journal of Paleontology (2010) 84 (2): 267-287.
... interior, producing a siphuncle band. The skeleton was produced by a deep-bodied animal of demersal life habits. The species B. uncinata, B. harrisi and B. alabamensis voltzi proposed by Palmer (1937) are synonymised with B. ungula. The species B. veatchii and B. saccaria of Palmer (1937) are considered...
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Journal Article
Published: 11 April 2017
Journal of Paleontology (2017) 91 (3): 512-547.
... of the richest shark faunas from the Neotropics. Strontium geochronology indicates an age of 10–9.5 Ma for the chonrichthyan-bearing strata. Field efforts resulted in 1429 identifiable specimens comprising at least 31 taxa, of which at least eight are new to the documented fossil...
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Journal Article
Journal: Paleobiology
Published: 01 May 2018
Paleobiology (2018) 44 (2): 251-262.
... and oceanographic Neogene events modulated the diversification trends of marine taxa in the TPSA (Valenzuela-Toro et al. 2013 ; Villafaña and Rivadeneira 2014 ). In addition, profound changes were observed in Neogene mollusk faunas along the TPSA (Rivadeneira and Marquet 2007 ; Kiel and Nielsen 2010 ). Recently...
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Journal Article
Journal: Paleobiology
Published: 01 May 2008
Paleobiology (2008) 34 (2): 210-228.
... ; Gould 1988 ; McShea 1994 ), especially during the O4–D2 interval. This increase is unlikely to be driven by mid-Paleozoic biases in sampling against small taxa because of the effort to locate samples encompassing whole biotas (see “Materials and Methods”). Combined with the statistical results above...
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Journal Article
Published: 01 May 2018
Journal of Paleontology (2018) 92 (3): 412-431.
... swimming and were, like Nautilus , most probably demersal animals (Dzik, 1984 ; Westermann, 1998 ). In some species, the last whorl becomes uncoiled, which indicates a changed mode of life from nektonic towards a demersal habit, with limited swimming ability (Flower, 1955 ). The first tarphycerids...
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