Cyllo sepulta

Jong, Rienk De, 2017, Fossil butterflies, calibration points and the molecular clock (Lepidoptera: Papilionoidea), Zootaxa 4270 (1), pp. 1-63 : 38-39

sepulta . Cyllo sepulta Boisduval, 1841

Fig. 17.

Nymphalidae : Satyrinae .

France, Bouches-du-Rhône, Aix-en-Provence, France; Chattian–Aquitanian, late Oligocene–early Miocene.

Depository: MNHN (holotype, IPM B-24309).

Published figures: Leestmans (1983: Figs 6–8, 18); Murata (1998: Figs 17–23); Nel & Nel (1986: Fig. 2 a, Pl. I Fig. 2 ); Scudder (1875: Pl. I Figs 8–17).

Original description ( Boisduval 1841) cited by Scudder (1875) who dedicated a long discussion to the fossil. Further discussed by Nel & Nel (1986). The wing venation and pattern is rather well preserved. The thorax and legs (hindlegs only) lack diagnostic characters. The forewing radial formula is 1, 2+(3+(4+5)) according to Scudder, 1, 2, 3+(4+5) according to Nel & Nel (who studied the holotype), M3 and Cu1 originating from the same point at the lower distal end of the cell, meaning that ldc runs from the origin of Cu1 to M2, cell closed but crossvein weak, basally swollen veins absent. Hindwing with two anal veins, cell closed but crossvein weak. Forewing with falcate apex, hindwing forming a tail at M3. Scudder considered the visible wing pattern to be that of the upperside, but Nel & Nel (1986) convincingly showed it to be the pattern of the underside.

This specimen is generally placed in Satyrinae on basis of wing shape and pattern (submarginal ocelli). Boisduval (1841) assigned it to a recent genus, Cyllo , which is a junior synonym of Melanitis , see Hemming (1967). Butler (1873, cited by Scudder 1875) erected the genus Neorinopsis, although Scudder misspelled the fossil Neorinopis , repeated by later authors. In wingspan and pattern it is intermediate between recent satyrine genera Neorina (Southeast Asia), Antirrhaea (South America), and Anchiphlebia, a junior objective synonym of Antirrhaea (see Hemming 1967). Nel & Nel (1986) are clear in their opinion about this similarity: “… le rapprochement indiqué par Scudder (1875, tableau p. 28) avec des genres sud-américains (Anthirrhaea, Anchiphlebia), perd ainsi toute raison d’être.” (“… therefore, the similarity to South American genera (Anthirrhaea, Anchiphlebia), indicated by Scudder (1875, table p. 28), lacks any credibility.”). According to Scudder (1875), the venation is reminiscent of Neorina , Lethe , Zophoessa and Debis , of which the latter two are synonyms of Lethe (see Gaede 1931), but the radial vein arrangement is different, a remarkable observation by Scudder, since the common origin of M3 and Cu1 of the forewing in Neorinopsis does not agree at all with the situation in these genera, but is similar to what is found in the extant genus Elymnias .

The Satyrinae do not have a unique and universal morphological apomorphy ( Ackery et al. 1999; but see Freitas & Brown 2004: 369), and the justification for its maintenance as a monophyletic group comes from a combined analysis of morphological end molecular data ( Wahlberg et al. 2009). Similarly, even though the nine satyrine tribes recognized in a recent molecular analysis of the subfamily by Peña & Wahlberg (2008) largely agree with morphological studies, an analysis of the apomorphies of the tribes still is wanting. Thus, opinions of relationship to date have been based on similarity.

On the basis of the wing pattern Nel & Nel (1986) agree with Butler (1873) and Scudder (1875) about a close relationship with the recent satyrine genus Neorina . They indicate that Neorinopsis, Neorina and Pseudoneorina coulleti (also a fossil species, see under the species name) form a monophyletic group whose ancestor lived in the Eocene or earlier, maybe Upper Cretaceous, f Europe or Asia. As correctly remarked by Nel & Nel (1986), the common origin of veins M3 and Cu 1 in the forewing is a character found in recent taxa only in the satyrine tribe Elymniini (Old World Tropics), which is not closely related to Neorina (tribe Zetherini , Peña & Wahlberg 2008). Since wing shape in Elymniini is generally crenulate and the pattern is very different, Nel & Nel (1986) conclude that the venational similarity is due to convergence. Alternatively, the similarity of Neorina, Neorinopsis and Pseudoneorina in wing design could well be based on symplesiomorphy or convergence, and probably the mimetic wing pattern of Elymniini , mimicking, among others, Danainae , may well have evolved after the common origin of M3 and Cu1 arose in an ancestor of Neorinopsis and Elymniini . In view of the variability and plasticity in the development of eyespots in Satyrinae , where even seasonal changes may lead to very different patterns ( Brakefield et al. 1996), one should hesitate in providing more weight for similarity in wing design than for similarity in a unique structural character. In this context, the recent publication on Mesozoic kalligrammatid lacewings (Neuroptera) with a surprisingly butterfly-like appearance, including eyespots ( Labandeira et al. 2016), which lived several tens of millions of years before the origin of butterflies must be mentioned. This study emphasizes that appearance alone is not a reliable guide to relationship. In an interesting examination, Martins-Neto et al. (1993) described a fossil butterfly from Brasil ( Neorinella garciae ) with the same remarkable connate origin of M3 and Cu1 from the forewing cell as found in Neorinopsis and Elymnias (see also Neorinella garciae ).

Pseudoneorina , Neorinella , Satyrites and Neorinopsis have been classified by Wahlberg & Peña (2015), without comment, as fossil genera belonging to the subtribe Lethina of the tribe Satyrini , while Neorina has been placed in the tribe Zetherini . For Neorinopsis and Neorinella this placement appears incorrect in view of the venation, and for Satyrites it is not certain at all (see the discussion under reynesii ). However, insights in the interrelationships among the tribes of Satyrinae are still in flux and would be altered with new analyses that apply other or new (molecular) characters and other sets of taxa. Consequently, Wahlberg & Brower (2006) presented the phylogeny of the tribes of Satyrinae quite differently from the scheme of Peña & Wahlberg (2008) for the same tribes, and one year later the situation has again changed drastically ( Wahlberg et al. 2009) ( Figs 19–21 ). Evidently, if Neorinopsis sepulta (about 28–34 Ma) or Neorinella garciae (about 20–30 Ma) are used to calibrate the molecular clock for Satyrinae , and the calibration point is placed at the base of Elymniini , it makes considerable difference whether it is done in the tree of Fig. 19 or in the tree of Fig. 20 .

As to geographical relationship, if Neorinopsis and Neorinella are assigned to Elymniini on the basis of the connate origin of M3 and Cu1 from the forewing cell, Neorinella would be an example of a fossil found on another continent than the most closely related extant taxa, particularly as Elymniini currently are restricted to tropical Asia with a single species in Africa (see http://tolweb.org/ Elymniini /70274). See the section on Biogeographic considerations.

Figures

FIGURE 2. Apomorphies, their placement on a tree, and the assignment of calibration points. See text for explanation.

FIGURES 19 – 21. Three phylogenetic trees for Nymphalidae: Satyrinae. See text for explanation.