Liptena durbania Bethune-Baker, 1915

Libert, Michel, 2023, Taxonomic notes on Liptena durbania Bethune-Baker, 1915 (Papilionoidea: Lycaenidae: Poritiinae), Metamorphosis 34 (1), pp. 29-34 : 29-31

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).

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.

Liptena durbania durbania Bethune-Baker, 1915 ( Figs

Figures

Figure 1 – Map of Central Africa showing the distribution of Liptena durbania subspecies

Figures 9–21: 9, 10 L. d. durbania ♂ (Obout, Cameroon) R & V; 11 L. d. durbania ♀ (Obout, Cameroon) R & V; 12, 13 L. d. durbania ♂ (Ebogo, Cameroon) R & V; 14, 15 L. d. eukrinoides ♂ (Kasugho, NE DRC) R & V; 16, 17 L. d. eukrinoides ♀ (Musasa, NE DRC) R & V; 18, 19 L. d. eukrinoides ♀ (HT f. obsoleta) R & V; 20, 21 L. d. bergeri ♂ HT, R & V.