Taxonomic notes on Liptena durbania Bethune-Baker, 1915 (Papilionoidea: Lycaenidae: Poritiinae)
Author
Libert, Michel
text
Metamorphosis
2023
2023-04-30
34
1
29
34
http://dx.doi.org/10.4314/met.v34i1.3
journal article
10.4314/met.v34i1.3
2307-5031
14119290
Liptena durbania
Bethune-Baker, 1915
The description of
Liptena durbania
is based on a male from Bitje (
Cameroon
), and the species is not uncommon in this country where some
70 specimens
have now been collected (most of them in the ABRI collection). It has also been observed in neighboring countries:
Gabon
(Vande weghe, 2010: 248 and pl. 106), Congo (Stempffer, 1965: 1454) and
CAR
(ABRI).
D'Abrera (2009:649)
limits the distribution of
L. durbania
to
Cameroon
and
Congo
, but Williams (2022) mentions its presence in northeastern
DRC
, citing
Ducarme (2018: 31)
. However, Ducarme (
ibid
.) also mentions the existence in NE
DRC
of
L. bergeri
Stempffer
et al.
, 1974
, a species which is only known by its
holotype
from Kafakumba (southern
DRC
) and which, according to its authors, is distinguished from
L. durbania
only by male genitalia. Obviously, this point deserves further investigation.
A new visit to Robert Ducarme's collection first showed that, given their variability, it was impossible to distinguish two taxa among the specimens in this collection, then that the male genitalia of the single taxon (Figs. 6–8) are indeed close to those of
L. bergeri
,
which are illustrated in the description of this species (Stempffer
et al.
, 1974 – Fig. 49), side by side with those of
L. durbania
(
ibid
. – Fig. 48).
Figure 1
– Map of Central Africa showing the distribution of
Liptena durbania
subspecies
Figures 2 to 8
– Male genitalia of
Liptena
d.
durbania
(
2 to 5
. ♂ Ototomo, near Yaoundé, Cameroon; prep. Libert 120-205) and of
L. d.
eukrinoides
(
6 to 8
. ♂ Kasuo, NE DRC; prep. Libert 120-206). 2, 6. Left lateral view of genitalia.
3
. Three-quarter posterior view of penis and fultura.
4, 7
. Ventral view of the valves.
5, 8
. Dorsal view of the uncus and of the dorsal part of the tegumen.
As far as can be judged from Fig. 49, the main, and perhaps the only, difference is the much more indented uncus of the
Kivu
males, which are therefore closer in this character to
L. durbania
(Fig. 48). On the other hand, we find in the
Kivu
males the wide ventral plate of the valves which distinguishes
bergeri
from
L. durbania
(it is possible that there are minor differences in the shape of the subunci or the dorsal tip of the valves, but the figures do not make it possible to say).
There is therefore in Kivu a taxon fairly close to both
L. durbania
and
L. bergeri
. The proximity of this taxon to
L. durbania
is confirmed by the relatively clear but limited facies differences and the DNA barcode analysis which shows a difference of about 1% between the populations of
Cameroon
and Kivu.
Two other taxa also similar to both
L. durbania
and to the specimens from
Kivu
have been described.
obsoleta
Dufrane, 1953
was described as a female form of
L. eukrines
(
Dufrane, 1953: 49
)
. Williams (2022) treats
obsoleta
as a synonym of
L. eukrines
, but it is also considered a synonym of
L. minziro
Collins & Larsen,
2008
in the description of this species close to
L. eukrines
(
Collins & Larsen, 2008: 56
)
; these decisions can only be explained by the fact that no illustration of the
type
exists. Indeed, although the type-locality is in
South Kivu
(Kamituga, near Mwenga, south of Bukavu),
obsoleta
is neither illustrated nor even mentioned by
Berger (1981)
(probably because the
type
is not in the MRAC collection but in that of the RBINS). Thanks to Stefan Kerkhof, it could be photographed, and the photos show beyond a shadow of a doubt that the specimen is much closer to
L. durbania
than to
L. eukrines
.
This provides further evidence that a good illustration is more useful than a description, however detailed it may be.
It is therefore very likely that the
type
of
obsoleta
belongs to the same taxon as the specimens collected further north [see the case of
L. kamitugensis
Dufrane, 1953
, whose type-locality is also Kamituga (Libert, 2022a)].
eukrinoides
Talbot, 1937
was described as a species of
Liptena
from
two specimens
collected in south-western
Uganda
. Although Talbot compares
L. eukrinoides
to
L. eukrinaria
Bethune-Baker, 1926
, the
type
of the latter (photographed at NHM in 1996) looks much more like
L. durbania
than like
L. eukrinoides
. More recently, about
twenty specimens
were collected in north-western
Tanzania
(Minziro, not far from the type-locality of
L. eukrinoides
), by Jan Kielland and then by ABRI collectors (
Kielland, 1990
;
Congdon & Collins, 1998: 60
). All of these specimens are in the ABRI collection, and photos sent by S. Collins do not show any differences with the specimens from Kivu.
The genitalia of
L. eukrinoides
have not been described or figured, nor were they examined by Stempffer (1967: 54), but the abdomen of male from Minziro was sent by S. Collins, and dissection showed genitalia identical to those of the males from
Kivu
(Figs 6–8). It follows 1) that
eukrinoides
is the name that should apply to specimens from
Kivu
, and 2) that
obsoleta
is a synonym of
eukrinoides
(
syn. nov.
)
It therefore appears that there are three allopatric taxa (map,
Fig. 1
),
L. durbania
;
L. eukrinoides
and
L. bergeri
, whose facies are not very different and for which it is necessary to determine whether it is justified to treat them as species distinct from
L. durbania
.
The barcode of
eukrinoides
is similar to that of
L. durbania
(∆ ≈ 1%), whilst male genitalia bring it closer to
bergeri
, whose barcode has not been sequenced. The female genitalia of
eukrinoides
and
L. durbania
are also similar; but the female of
bergeri
is unknown.
These modest differences do not demonstrate whether
eukrinoides
is closer to
durbania
or to
bergeri
, and the status quo could be maintained, with the three taxa as distinct species. However, the modesty of these differences, the allopatry of the three taxa, their close resemblance and the existence of intermediate specimens within the population of
eukrinoides
in
Kivu
, strongly suggests that there are three subspecies of
L. durbania
:
L. d.
durbania
, from
Cameroon
to
CAR
;
L. d.
eukrinoides
(
stat. rev.
; NE
DRC
, W
Uganda
and NW
Tanzania
);
L. d.
bergeri
(
stat. rev.
), which is only known from Shaba.