comment on this calibration
Myodocopa
Lineage (NCBI):
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» Ostracoda
» Myodocopa
| node name Myodocopa 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 443.8 Ma The holotype of L. incuba was collected from siltstone of the Original Trilobite Bed, Walcott Quarry of Beecher's Trilobite Bed, in the Frankfort Shale of upstate New York (Siveter et al., 2014). Beecher's site within the Frankfort Shale is within the Lorraine Group, part of the regional Maysvillian Stage of the Cincinnatian Series (Farrell et al., 2009, 2011). Globally, the Maysvillian (Amplexograptus manitoulinensis Graptolite Zone) corresponds to the early Katian Stage, from the base of the Diplacanthograptus caudatus Graptolite Zone to the base of the Pleurograptus linearis Graptolite Zone (Bergström et al., 2009). The upper boundary of the Katian is 445.2 Ma ± 1.4 Myr, providing a minimum age of 443.8 Ma. | ||
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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 | ||
YPM IP 307300 | ||
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phylogenetic justification
To date, L. incuba is yet to be included in an extensive phylogenetic analysis, but a number of features confirm both its placement within Myodocopida, and therefore Myodocopa. Specifically, the arrangement of setae on the antenula of L. incuba is currently only observed among extant myodocopid ostracods (Kornicker, 1981). |
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phylogenetic reference(s)
Siveter, D.J., Tanaka, G., Farrell, Ú.C., Martin, M.J., Siveter, D.J., and Briggs, D.E.G. 2014. Exceptionally preserved 450-million-year-old ordovician ostracods with brood care. Current Biology 24, 801–806.
Kornicker, L.S. 1981. Revision, distribution, ecology, and ontogeny of the Ostrocode subfamily Cyclasteropinae (Myodocopina, Cylindroleberididae). Smithson. Contrib. Zool. 319, 1–548
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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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