Fossil butterflies, calibration points and the molecular clock (Lepidoptera: Papilionoidea) Author Jong, Rienk De text Zootaxa 2017 4270 1 1 63 journal article 32975 10.5281/zenodo.583183 6c479acc-8b18-4f0b-a6e5-85bcd6d7b6b7 1175-5326 583183 2D00AFF5-4FE2-4EC1-A328-C8670CFB8D6D montana . Lethe montana Miller, Miller & Ivie, 2012 Nymphalidae : Satyrinae . USA , Montana , Canyon Ferry Reservoir; Rupelian, early Oligocene. Depository: holotype , Museum of Rockies , Montana State University , Bozeman (part and counterpart, MOR No . MV-152). Published figures: CoBabe et al . (2002 , Fig. 4 c), Miller et al . (2012 : Figs 1–5 . The fossil consists of a well preserved part and counterpart of a forewing. In their diagnosis the authors state that “… the unbranched forewing radial veins … indicate thet this fossil is … not a member of the Hesperioidea.” Rather, this should read “the branched forewing radial veins”, but the conclusion is correct. Moreover, the absence from the cubital spur and vein 3A eliminates Papilionidae from consideration. The authors also eliminate Pieridae , since M1 branches off the cell, although branching of M1 off R3 is widespread in Pieridae but not universal. The remark that Riodinidae or Lycaenidae can be eliminated because the “… veins are not simple in that they do not arise from the base or from the radius or cubitus proper …”, is not clear to me. The authors arrive at the conclusion that the fossil belongs to the Nymphalidae , and since the forewing cell is closed, the subcostal vein is thickened at its base and there is a prominent ocellus in M1-M2, assignment to the Satyrinae seems obvious. The only problem is, that the basal part of the wing with the swelling of the subcostal vein, as represented in their reconstruction in Fig. 5 , is absent from the fossil ( Fig. 1 ) and from the interpretation of the fossil in Fig. 2 . See also the discussion under Lethe (?) corbieri on the absence of a basal swelling in Lethe . There is no convincing evidence for treating Lethe montana differently than Lethe (?) corbieri as far as its use as calibration point concerns. They are approximately the same age. See also under Biogeographic considerations .