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 florissanti . Barbarothea florissanti Scudder, 1892 Nymphalidae : Libytheinae . USA , Colorado , Florissant; late Priabonian, late Eocene. Depository: Scudders' specimen is presumed lost ( Shields 1985 ). Published figures: Emmel et al . (1992 : Fig. 1 /2). Very similar to the fossil Prolibythea vagabunda and also placed in the subfamily Libytheinae (Nymphalidae) by Scudder (1892) , followed by Emmel et al . (1992) . Fairly well preserved. Antenna tricarinate (autapomorphy of Nymphalidae ), club very gradual. Two legs visible, not reduced, possibly middle legs. Palpi, 2nd segment oblique; apical joint horizontal, only a little more than two-thirds the length of the 2nd (i.e., relatively longer than in most butterflies, but shorter than in any known member of the Libytheinae ). Venation as in Prolibythea vagabunda Scudder that is plesiomorphic and not indicating relatedness. Hindwing relatively broad and rounded, costa concave, termen crenulate. Forewing slightly falcate. The long palpi agree with the Libytheinae , but apparently they had not yet reached the state found in extant members of the subfamily. Although the palpi of Libytheinae are relatively long, they are not unique, some other nymphalids having similarly long palpi and a similar venation as well (e.g. Eunica , a member of the Biblidinae ). The apomorphic character states of the Libytheinae mentioned by Ackery et al . (1999) are not visible in the fossil, but the extension of the termen of the forewing at the end of M2 seems to occur in Libytheinae only as judged from the numerous venational diagrams in Schatz & Röber (1892) . In other butterflies, if there is an extension (a tooth) it is at or just below M1. It is not clear why Scudder did not place it in Prolibythea , although he mentioned the similarity. See also the discussion by Kawahara (2013) , who synonymized it with Oligodonta florissantensis and placed it in the extant genus Libytheana on the basis of an analysis of morphological characters. However, since apomorphies are not clear and the palpi are definitely shorter than in extant members of Libythea and Libytheana , I hesitate placing it in an extant genus and suggest that it should be placed at the stem node of the subfamily, if used for calibration purposes. See also under Prolibythea vagabunda .