APPENDIX S1
Taxonomic Summary of C. egesta and C. confusa
C. egesta s. s. flies throughout West Africa and western Central Africa from Sierra Leone to
Cameroon. Males vary considerably in the extent and intensity of dark markings. This variation is
at least partly seasonal, particularly from Sierra Leone to Nigeria, with dry season morphs being
lighter than wet-season morphs (compare Figure S2A and B). In the lighter forms, the two brown
bars stretching from the forewing inner margin to vein 1 or 2 are relatively pale, and the outer bar is
shorter than the discal one, often almost obsolescent (f. degesta; Figure S2A). Variation in dark
markings is also partly geographical. Males become darker and less variable than those described
above towards the wetter eastern end of the range in eastern Nigeria and Cameroon (Figure S2C).
In fact, in these areas they are just as dark as sympatric populations of C. confusa (Figure 3, main
text; Figure S2C and D).
C. confusa flies through Central and West Africa from the Sanaga River in Cameroon (a wellknown biogeographic boundary) eastwards to Tanzania/Uganda and south to Ikelenge in Zambia.
Males of this species also vary in the extent and intensity of dark markings, becoming increasingly
darker towards the east in what may be a cline (Figure S2E-F). Cameroon populations are the
lightest, and, as mentioned above, do not differ in melanization from populations of C. egesta in
eastern Nigeria and Cameroon (Figure S2D). Eastern populations are the darkest; some individuals
can be very heavily overlaid with dark scaling, especially in western Tanzania and eastern Congo
(Figure S2F).
While males from sympatric populations of C. egesta and C. confusa are similar in the extent of
dark markings, they differ in the tone of the wing ground color. C. egesta males from Cameroon
(Amiet’s “egesta orange”) are more orange than C. confusa males. This difference is subtle, and
only becomes clear when multiple fresh specimens are compared side by side (Figure 3, main text;
J-L Amiet, pers. comm.). Moreover, the more orange ground color of Cameroon C. egesta
populations not only sets them apart from C. confusa, but it also sets them apart from conspecific
populations further to the west.
The females of both species are highly variable – particularly in the size and color of the light patch
on the forewing costa. There may be slight heterospecific variation in this trait, but the difference is
not discrete and individual females cannot currently be identified to species by morphological
features.
Detailed Taxonomy of C. egesta and C. confusa
Cymothoe egesta (Cramer, 1775)
Papilio egesta Cramer, 1775 in Cramer, [1775-6]. Die Uitlandsche Kapellen voorkomende in de drie waerrelddeelen
Asia, Africa en America 1:72 (16 + 155 pp.). Amsteldam & Utrecht.
Type locality: “Surinamen”. [False locality.]
Note: Surinam is obviously a false type locality, one of many in Cramer’s descriptions. It is assumed that the correct
type locality is Sierra Leone, from where much of Cramer’s African 1775-1779 material came. Cramer’s specimens
came from many different sources and were dispersed upon his death. It is therefore difficult to identify types or
syntypes, and virtually all use of Cramer names are based on the somewhat stylized, but usually clear, color paintings in
his three book volumes (Chainey, 2005).
=Cymothoe egesta var. degesta Staudinger, 1890 (as var. of Cymothoe egesta). Stettiner Entomologische Zeitung
50:418 (412-422). [mostly a dry season form]
Type locality: Goldküste [=Ghana].
The type locality is said by Ackery et al. (1995) to be West Africa. It is probably Sierra Leone,
from where most African forest butterflies at the time reached Europe. Of the fifty or so African
butterflies described by Cramer, a few are from the Cape Province in South Africa, and the rest are
species commonly found in Sierra Leone (including many species and subspecies endemic to West
Africa. Staudinger (1890) certainly thought Sierra Leone was the type locality and Aurivillius
(1898) only mentions Sierra Leone.
In his description of var. degesta, Staudinger (1890) thought it might be considered a local variety
as the “Egesta von der Goldküste [Ghana]”, but recognized that similar forms occurred also in
Sierra Leone. C. egesta is variable in Ghana and var. degesta is a form with reduced black
markings that is usually associated with the dry season (Fig. S2A and B). We consider it to be a
clear junior synonym of the moderately variable nominate C. egesta. No consistent geographical
variation was found between Sierra Leone and the Cross River Loop in eastern Nigeria, but the dry
season degesta is less frequent in the extremely wet habitats prevailing in the east. The females are
more variable than the males, especially in the size of the light forewing subapical patch, and we
have not found any certain character to distinguish them from the females of C. confusa, which vary
in the same manner.
In 1997 Amiet discovered two slightly different forms of C. egesta s. l. flying together in the
Yaoundé area of Cameroon, east of the Sanaga River (Amiet, 1997). The two forms clearly differed
in larval coloration and host plant choice, but showed only slight differences in adult morphology.
Compared to C. confusa from the same localities, the form that Amiet called “egesta orange” had a
somewhat squatter forewing, a more scalloped margin, and a subtle orange tone to the male
ground-color (Figure 3, main text), the latter being more consistent than the other characters. The
genetic data in this study clearly show that this orange form is affiliated with C. egesta s. s, and that
it occurs sympatrically with C. confusa. Very little material is available from western Cameroon
between the Nigerian Border and the Sanaga River. A Cameroon male C. egesta from near the
Nigerian border in coll. Libert is certainly not orange and differs from six “egesta orange” males
from east of the Sanaga River that were collected in the same area south of Yaoundé where Amiet
worked (M. Libert, photo).
In summary, Aurivillius (1908-25) gave the distribution of C. egesta as stretching from Sierra
Leone to the Gold Coast [Ghana], while his own ssp. confusa was found from Old Calabar in the
Cross River Loop in eastern Nigeria eastwards. In this he was followed by Ackery et al. (1995) and
by Larsen (2005). However, the data for this paper include three DNA sequences showing only C.
egesta in the Cross River Loop area (DPK 1-3). Moreover, the genetic studies extend the eastern
edge of C. egesta’s range through central and into south Cameroon (Campo), well beyond the
Sanaga River. In these areas of Cameroon, C. egesta is in sympatry with C. confusa and males have
a subtly orange ground color.
Cymothoe confusa Aurivillius, 1887
Cymothoe confusa Aurivillius, 1887. Öfversigt af Kongliga Vetenskaps-Akademiens Förhandlingar. Stockholm, 5:
310 (305-314).
Type locality: Congo: “Brazzaville”.
Cymothoe egesta var. confusa Aurivillius, 1887. in Die Afrikanischen Tagfalter, volume 13: 1-614 in Seitz, A. 19081925.
This taxon was originally described by Aurivillius (Aurivillius, 1887) as a distinct species.
However, Aurivillius himself subsequently treated it as an eastern subspecies of C. egesta with a
range from Cameroon (east of the Sanaga River) to Uganda, northern Zambia, and western
Tanzania (Aurivillius, 1898). The extent of black markings increases towards the east. The
holotype of C. confusa from Congo (similar to the specimen pictured in Fig. S2E), is darker than
any male we have seen from Cameroon, and even darker specimens may be found further east,
especially in the Mahale area of western Tanzania. The cline seems to be somewhat irregular at its
eastern end, and additional material may show that the dark eastern populations deserve a
subspecific name.
Central Cameroonian populations of C. confusa are the lightest, and we have been unable to find
any morphological feature that can clearly distinguish their adults from allopatric West African C.
egesta; the male Cameroonian C. confusa are darker on average but fall within the range of the
variation seen within West African C. egesta. They also share the same insipid yellow tone of the
ground color. Adults from Central Cameroonian populations of C. confusa are subtly different,
however, from sympatric populations of C. egesta. In the area of species overlap, C. egesta males
are recognizable by the more orange ground color – more orange than both C. confusa and typical
western C. egesta. As emphasized to us by J.-L. Amiet, this is mainly apparent when comparison is
made between series of fresh material (Fig. 3, main text). Unlike the adult morphology, host plants
and early stages of the two species are discretely different in sympatry.
The known area of overlap of C. confusa with C. egesta is limited to Cameroon east of the Sanaga
River, a known biogeographical boundary. However, virtually no information is available from
Cameroon west of the Sanaga River, and the limited material that does exist from the area does not
show the subtle orange tone of “egesta orange” (Natural History Museum (BMNH), London, and
M. Libert).
Cymothoe egesta var. megaesta Staudinger, 1890
Cymothoe egesta var. megaesta Staudinger, 1890. Stettiner Entomologische Zeitung, 50: 418 (412-422).
Type locality: Cameroon: “Kamerun (Barombi-Station)”.
Treated as a junior synonym of C. egesta confusa (Cramer, 1775-1776) by Ackery et al. (Ackery et al., 1995).
Cymothoe ? megaesta Staudinger, 1890. Amiet (Amiet, 1997)
Cymothoe megaesta Staudinger, 1890. Larsen (Larsen, 2005). [in error]
This taxon was described from western Cameroon in comparison with C. egesta from Sierra Leone.
The main difference cited is that megaesta are much blacker both on the hindwing and in terms of
the greater development of the two discal bands of the forewing that stretch from the inner margin
to vein 2. The description could pertain to either of the two species in Cameroon.
Amiet (1997) understandably suggested that his “egesta orange” might match megaesta, which is an
available name. Larsen (2005) went further and wrote: “In Cameroun there is a closely related
species, C. megaesta Staudinger, 1890. It is smaller, more orange in tone, with more strongly
scalloped wing margins, a darker female, and a different larva (figured in color by Amiet 1997).
DNA studies have recently confirmed its specific status (L. McBride, pers. comm.).” This was
written before the DNA of nominate C. egesta had been sequenced, and thus before it became clear
that it was so closely affiliated with C. “egesta orange”, and that it was actually C. confusa that
differed.
It is quite likely that megaesta does pertain to egesta since its type locality is about 100 km west of
the Sanaga River, which appears to be the western border of C. confusa according to the genetics.
However, the situation in far western Cameroon (Cross River area) is effectively unknown, and
clarification of the status of megaesta must await fresh collections and further DNA studies.
References
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