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
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
.