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Podocopa
Lineage (NCBI):
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» Ostracoda
» Podocopa
| node name Podocopa Look for this name in NCBI Wikipedia Animal Diversity Web | ||
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recommended citations Wolfe et al. 2016 |
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node minimum age 415.38 Ma Specimens of C. submagna were recovered from two localities in Podolia,Ukraine: Kasperovcy village, left border of the river Seret (type locality),and from the right escarpment of the River Dniester near the village Ivanye Zlote (Olempska et al., 2012). The type locality, part of the Chortkov/Chortkiv Horizon, underlies the second locality, which is part of the Ivanye Horizon (Filipiak et al., 2012; Olempska et al.,2012). Thus we must use the Chortkiv age as a minimum constraint on the age of C. submagna, to provide the narrowest interval of clade divergence. The Chortkiv Horizon comfortably lies within the middle Lochkovian stage of the Early Devonian (Filipiak et al., 2012;Małkowski et al., 2009; Plotnick, 1999). Conodont biostratigraphy places the upper boundary of the Chortkiv Horizon at the end of the Caudicriodus postwoschmidti Biozone, the oldest conodont Biozone within the Devonian (Drygant and Szaniawski, 2012). Spline fits on radiometric ages for the Devonian place the C. postwoschmidti Biozone at 417.27 Ma with a duration of 1.89 Myr (Becker et al., 2012). Thus the end of the C. postwoschmidti Biozone, and a minimum age for the first appearance of C. submagna, is 415.38Ma. | ||
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node maximum age 509 Ma As in Oakley et al. (2013),we suggest the maximum age of ostracods must be 509 Ma, the age of the Burgess Shale. Myodocope ostracods possess bivalved, calcified carapaces, which are preserved from many other Burgess Shale arthropods. There is no taphonomic reason why they would not have been preserved from ostracods. The Burgess Shale type locality is from Unit 3 of the Collins Quarry on Mount Stephen in the Canadian Rocky Mountains, British Columbia, which falls within the Kicking Horse Shale Member of the “thick” Stephen Formation (Aitkin, 1997; Caron et al., 2010; Stewart, 1991), also referred to as the Burgess Shale Formation (Fletcher and Collins, 1998, 2003). This unit yields trilobites from the Polypleuraspis insignis Subzone of the Glossopleura Zone (Fletcher and Collins, 1998), and is the oldest soft bodied fossil excavation of the Burgess Shale sites. The age of the Glossopleura Zone corresponds to the Cambrian Series 3 Stage 5, giving a maximum constraint of 509 Ma. | ||
| primary fossil used to date this node | ||
ZPAL O.60/001 | ||
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phylogenetic justification
C. submagna, is very similar to modern podocopes, particularly sigilloideans and darwinuloideans, with which it shares a particular adductormuscle scar pattern, long terminal seta on the seventh limb pair, and a furca with large distal setae (Olempska et al., 2012). |
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phylogenetic reference(s)
Olempska, E., Horne, D.J., Szaniawski, H., 2012. First record of preserved soft parts in a Palaeozoic podocopid (Metacopina) ostracod, Cytherellina submagna: phylogenetic implications. Proc. R. Soc. B Biol. Sci. 279, 564–570.
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| tree image (click image for full size) | ||
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Figure 10 from Wolfe et al (2016).
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