comment on this calibration


 node name
Amphiesmenoptera     Look for this name in NCBI   Wikipedia   Animal Diversity Web
  recommended citations
Wolfe et al. 2016
  node minimum age
195.31 Ma
Whalley (1985) noted the locality as Black Ven, Charmouth, Dorset, on the Jurassic Coast of England. This was further specified as calcareous flatstone, probably from Bed 75a, of the Caenisites turneri ammonoid Zone (Sohn et al., 2012), or Microderoceras birchi Nodular of the “Shales with Beef” (Lang et al., 1923). Chemostratigraphy places the C. turneri (and M. birchi) Zones within the middle Sinemurian (Jenkyns et al., 2002). The upper boundary of the C. turneri Zone is thus dated to 195.31 Ma (Ogg et al., 2012b), providing a minimum age.
  node maximum age
411 Ma
A soft maximum age is estimated from R. praecursor, the oldest hexapod, from the Early Devonian (Pragian) Rhynie Chert of Aberdeenshire, Scotland. Spore assemblages of the Windyfield and stratigraphically underlying Rhynie Chert are dated to the early but not earliest Pragian to early (earliest?) Emsian (polygonalis-emsiensis Spore Assemblage Biozone) (Parry et al., 2011). Radiometric dating of the underlying Milton of Noth Andesite at ca. 411 Ma (Parry et al., 2011, 2013) has been subject to a dispute over its temporal relationship to hot spring activity associated with the cherts (Mark et al., 2011, 2013) and predates the biostratigraphic dating of the Rhynie Chert relative to the global dating of the base of the Pragian Stage. Therefore, a soft maximum constraint may be defined at 411 Ma for the Rhynie Chert.
 primary fossil used to date this node 
NHMUK In. 59397
Archaeolepis mane, Whalley, 1985
Location relative to the calibrated node: Crown

[show fossil details]
     Locality: Black Ven, Charmouth, Dorset
     Stratum: Bed 75a, of the Caenisites turneri ammonoid Zone
     Geological age: Jurassic, Mesozoic

More information in Fossilworks   PaleoBioDB

  phylogenetic justification
A. mane has been used to calibrate the lepidopteran root in previous molecular dating analyses (e.g.Wahlberg et al., 2013), where this relationship is based on two lines of evidence: wing scales and wing venation. The preservation of extremely rare scales completely covering the hindwing excludes A. mane from crown Trichoptera (Whalley, 1985, 1986) because Trichoptera only bear scales on the forewing. The presence of scales across the entirety of a wing with panorpoid venation can only signal amphiesmenopteran affinity. The Sc vein (with one visible branch) of A.mane is unlikely to represent the ancestral state for Lepidoptera, as the number of Sc vein branches varies in early-diverging moths, but is usually two branches, and this vein is multi-branched ancestrally in Amphiesmenoptera (Kukalová-Peck and Willmann, 1990; Minet et al., 2010; Sukatsheva and Vassilenko, 2011; Schachat and Brown, 2016). Although Trichoptera tend to have more wing veins than Lepidoptera, it is likely that fewer veins were lost by ancestral moths than is currently accepted in the literature, making distinctions between amphiesmenopteran branches difficult for Mesozoic fossils (Schachat and Brown, 2015, 2016). As reconstructed by Whalley (1986), the wing venation of A. mane differs markedly from the venation of crown Lepidoptera: there is a single, branched Cubitus vein, with CuP apparently absent, and all three branches of the anal vein reach the dorsum. In contrast, basal crown Lepidoptera nearly always have a CuP vein, and the anal vein becomes fused before reaching the dorsum (Common, 1973; Schachat and Brown, 2016). A position for A. mane within the crown group of Lepidoptera thus cannot be confirmed, but an identity as stem Lepidoptera is highly likely based on the wing scales in particular, in agreemen twith Whalley (1986). This fossil would therefore be within the crown group of Amphiesmenoptera.
  phylogenetic reference(s)
Whalley, P.E., 1985. The systematics and palaeogeography of the Lower Jurassic insects of Dorset, England. Bull. Br. Mus. Nat. Hist. Geol. 39, 107–189.
Whalley, P., 1986. A review of the current fossil evidence of Lepidoptera in the Mesozoic. Biol. J. Linn. Soc. 28, 253–271
 tree image (click image for full size) 
tree image
Figure 24 from Wolfe et al. (2016).