comment on this calibration
Annelida
Lineage (NCBI):
root
» Eukaryota
» Opisthokonta
» Metazoa
» Eumetazoa
» Bilateria
» Coelomata
» Protostomia
» Lophotrochozoa
» Annelida
| node name Annelida Look for this name in NCBI Wikipedia Animal Diversity Web | ||
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recommended citations http://palaeo-electronica.org/content/fc-1 Benton et al. 2015 |
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node minimum age 476.5 Ma ‘‘Xanioprion’ viivei is from a larger collection of scolecodonts from Kadriorg in Tallinn, North Estonia. The unit has been correlated, based on chitinozoans, to the Paroistodus proteus Conodont Zone (Hints and Nõlvak, 2006), the top of which is dated to 476.5 Ma (Cooper and Sadler, 2012). | ||
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node maximum age 636.1 Ma A soft maximum constraint is based on the maximum age interpretation of the Lantian Biota (Yuan et al., 2011). This, together with the Doushantuo Biota (Yuan et al., 2002), provides a series of Lagerstätten preserving the biota in Orsten- and Burgess Shale-like modes of fossilization. None of these Lagerstätten, least of all the Lantian, preserves anything that could possibly be interpreted as even a total group eumetazoan and on this basis we define out soft maximum constraint at 635.5 Ma ± 0.6 Myr (Condon et al., 2005) and, thus, 636.1 Ma. | ||
| primary fossil used to date this node | ||
GIT 424–19 | ||
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phylogenetic justification
Xanioprion shows the multi-element jaw apparatus composed of ventral mandibles and dorsal maxillae, apomorphies of scolecodonts. Scolecodonts are the jaws of annelids belonging to the extant clades Eunicida and Phyllodocida, and so located within crown-group Annelida (Parry et al. 2014). |
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phylogenetic reference(s)
Parry, L., Tanner, A., and Vinther, J. 2014. The origin of annelids. Palaeontology
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| tree image (click image for full size) | ||
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Figure 1 from Benton et al. (2014).
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