Aquisextana irenaei

Jong, Rienk De, 2017, Fossil butterflies, calibration points and the molecular clock (Lepidoptera: Papilionoidea), Zootaxa 4270 (1), pp. 1-63 : 29

irenaei . Aquisextana irenaei Théobald, 1937

Lycaenidae (?).

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

Depository: IGMF (holotype, Ma 1).

Published figures: Théobald (1937: Figs 2 , 3 ); Leestmans (1983: Fig. 19 ).

A fairly well preserved specimen, showing all wings (partly overlapping), head with appendices, thorax and abdomen. According to the original description, the fossil is seen from the underside. If correct, the legs are lost. The antennae thicken gradually towards the club. They are supposed to be inserted before the eyes. This is an impossible antennal inserting area and if the insect is really seen from the underside, the insertion of the antennae should not be seen at all. Eyes elongate-oval, hairy. No emargination at the base of the antennae (apomorphy of Lycaenidae ) mentioned, but otherwise not visible in ventral view. Forewing, length 21 mm; radial formula 1, 2, 3+4, with R4 ending on the outer margin just below the apex. This radial formula is found in Pieridae (e.g. Eurema Hübner , [1819]) and many Lycaenidae . In most Lycaenidae R4 terminates at the apex or on the costa close to the apex, in the Pieridae and in a few Lycaenidae , such as Curetis Hübner , [1819], an Oriental genus. In the Liphyrinae , an Old-World subfamily [see Eliot 1973], mentioned by Théobald (1937), the arrangement is not comparable, there being five radial branches and R4 terminates on the outer margin. As remarked by Théobald (1937), Curetis has a heavier thorax. Moreover, Curetis has a very different wing shape, triangular, with a straight outer margin and rectangular tornus, contrasting with the more elongate wing of the fossil, possessing a convex outer margin and rounded tornus.

On the wings a number of small dark spots are visible. Because of these spots, the general appearance and the eyes, Théobald believes his fossil to be a lycaenid, which is not close enough to any recent genus for assignment. Therefore, he erected a new genus for the fossil. From the discussion above it may be clear that evidence for a lycaenid relationship is hardly more convincing than for a pierid relationship, except that the modest size and the small dark spots that point to Lycaenidae . For want of better evidence, we follow Théobald and list this fossil under the Lycaenidae .

Figures

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

FIGURES 3 – 4. Wing venation of (A) Pareronia Bingham, 1907 (Pieridae), and (B) Hasora Moore, 1881 (Hesperiidae). See text for explanation.

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