comment on this calibration


 node name
Amalpighiata     Look for this name in NCBI   Wikipedia   Animal Diversity Web
  recommended citations
Wolfe et al. 2016
  node minimum age
306.9 Ma
Specimens are derived from the Francis Creek Shale Member of the Carbondale Formation, Mazon Creek, Illinois, of Westphalian D age (Baird et al., 1985; Shabica and Hay, 1997). The Westphalian D is equivalent to the latest Moscovian stage of the Pennsylvanian (Richards,2013). As the upper boundary of the Moscovian is 307.0 Ma± 0.1 Myr, this provides a minimum age of 306.9 Ma.
  node maximum age
521 Ma
A soft maximum age is obtained from the oldest mandibulate, Y. dianensis, which was recovered from the Yu'anshan Formation at Xiaotan section, Yongshan, Yunnan Province, attributed to the Eoredlichia–Wutingaspis Biozone (Zhang et al., 2007). Chinese Cambrian stratigraphy has been revised substantially and the Eoredlichia –Wutingaspis Biozone is no longer recognized (Peng, 2003, 2009). However, Eoredlichia is known to co-occur with Hupeidiscus, which is diagnostic of the Hupeidiscus-Sinodiscus Biozone, which is formally recognized as the second biozone of the Nangaoan Stage of the Qiandongian Series of the Cambrian of China (Peng and Babcock,2008). The Nangaoan is the proposed third stage of the Cambrian System for the International Geologic Timescale (Peng et al., 2012a).Thus, a soft maximum constraint can be established on the age of the lower boundary of the Nangaoan, which has been dated to 521 Ma (Peng et al., 2012a; Peng and Babcock, 2008).
 primary fossil used to date this node 
FMNH PE 22936
Mazoscolopendra richardsoni, Mundel, 1979
Location relative to the calibrated node: Crown

[show fossil details]
     Locality: Mazon Creek
     Stratum: Francis Creek Shale Member of the Carbondale Forma
     Geological age: Carboniferous, Paleozoic

  phylogenetic justification
M. richardsoni was coded by Fernández et al. (in press) for its morphological data based on descriptions and figures of Mundel (1979) and Haug et al. (2014b), and personal observation by G.D.E. of type and other material in the Field Museum. It was resolved as total-group Scolopendromorpha based on possession of autapomorphies of that order (e.g. single tergite on the forcipular/first leg-bearing segments, 21 pairs of trunk legs) but cannot be placed more precisely with regards to whether it is a stem- or crown group scolopendromorph. Nonetheless, its membership in Scolopendromorpha assigns it to crown Amalpighiata. The same calibration would apply were the putative clade Phylactometria endorsed in lieu of Amalpighiata.
  phylogenetic reference(s)
Fernández, R., Edgecombe, G.D., and Giribet, G. 2016. Exploring phylogenetic relationships within Myriapoda and the effects of matrix composition and occupancy on phylogenomic reconstruction. Systematic Biology 65:871-889.
 tree image (click image for full size) 
tree image
Figure 8 from Wolfe et al. (2016).