comment on this calibration


 node name
Uropygi     Look for this name in NCBI   Wikipedia   Animal Diversity Web
  recommended citations
Wolfe et al. 2016
  node minimum age
319.9 Ma
Of the uropygid fossils, the oldest are P. naufraga (formerly Prothelyphonus naufragus) from deposits of “Ziegelei-Grube,” Hagen-Vorhalle, Nordrhein-Westfalen, Germany (Brauckmann and Koch,1983; Tetlie and Dunlop, 2008). The fossil-bearing deposits are assigned to the Namurian B (Marsdenian) based on the Bilinguites metabilinguis R2c1 subzone of ammonoid stratigraphy (Brauckmann et al., 1994; Tetlie and Dunlop, 2008). The (late) Namurian-(early) Westphalian boundary is defined by the earliest occurrence of the goniatite Gastrioceras subcrenatum (Waters and Davies, 2006), but lacks a precise isotopic date. Pointon et al. (2012) estimated an age of c. 319.9 Ma for the base of the Westphalian (top of the Namurian, only slightly younger than the Marsdenian) based on Milankovitch cycles of sedimentation, giving a minimum age for P. naufraga.
  node maximum age
514 Ma
A soft maximum constraint comes from the oldest chelicerate W. barbarahardyae from the Emu Bay Shale on Kangaroo Island, SouthAustralia, which has been correlated based on trilobite biostratigraphy to the upper part of the P. janeae Zone in mainland South Australia (Jell in Bengtson et al., 1990; Fig. 2 in Jago et al., 2012). As this is equivalent to the Canglangpuan Stage in South China and the late Botoman inSiberia (Gehling et al., 2011, Fig. 9), the Emu Bay Shale can be dated to Cambrian Series 2, Stage 4, providing a maximum age of ~514 Ma.
 primary fossil used to date this node 
LWL Ar.K.1
Parageralinura naufraga, Tetlie and Dunlop, 2008
Location relative to the calibrated node: Stem

[show fossil details]
     Locality: “Ziegelei-Grube,” Hagen- Vorhalle, Nordrhein-Westfalen
     Geological age: Carboniferous, Paleozoic

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  phylogenetic justification
Tetlie and Dunlop (2008) interpreted Coal Measures uropygids to comprise a plesion on the stem of the extant Thelyphonidae, the sole extant family of Thelyphonida. A subchelate pedipalp is considered apomorphic of the crown group but is lacking in Geralinura and P. naufraga. This identifies them as crown Uropygi, and thus, Tetrapulmonata.
  phylogenetic reference(s)
Tetlie, O.E., Dunlop, J.A., 2008. Geralinura carbonaria (Arachnida; Uropygi) from Mazon Creek, Illinois, USA, and the Origin of Subchelate Pedipalps in Whip Scorpions. J. Paleontol. 82, 299–312.
 tree image (click image for full size) 
tree image
Figure 6 from Wolfe et al. (2006).