Bicyclus vandeweghei Brattström, 2015

Brattström, Oskar, Aduse-Poku, Kwaku, Collins, Steve C. & Brakefield, Paul M., 2015, Revision of the Bicyclus ignobilis species-group (Lepidoptera: Nymphalidae: Satyrinae) with descriptions of two new species, Zootaxa 4018 (1), pp. 57-79 : 72-73

Bicyclus vandeweghei Brattström , sp. nov.

( Figs. 23–26 , 29 , 35 )

Material studied. Type material. Holotype: ♂, Gabon, Bakouaka (00°08'N, 13°39'E), 16.xii.2007, G. Vande weghe leg., OB– ABRI –0068 ( ABRI). Paratype: ♀, Republic of Congo, Kelle (00°08'N, 13°39'E), i.1993, S. Collins leg., OB– ABRI –0140 ( ABRI).

Male description. Holotype forewing length 23 mm. The dorsal surface ground colour is a warm dark brown, gradually turning into a slightly darker hue towards the distal parts of the hindwings ( Fig. 23 ). The dorsal forewing has a quite large, but vague eyespot with an orange-brown outer ring and a tiny white central spot. There is a yellow-beige apical patch formed of a triangular patch in space 3 and 4 below the eyespot, merging with an hourglass shaped patch in spaces 4 and 5. Even if broken up by a darker vein above the cell, the patch extends faintly along the mid costal margin towards the wing base for a few millimetres, before fading into the ground colour. There is a sparse brush of hairs (about 3–4mm long) located basally in space 1b, directly above vein 1, extending towards the wing margin ( Fig. 26 ). The hairs are similar in colour to the wings, and without good contrasting light are very hard to see clearly. There are no specialised androconial scales under the area covered by the hairs forming the brush.

The hindwing has a hair brush placed close to the base of the cell, the brush is light beige at the base and gradually fades into a pale white yellow at the tip. It is covering a pit at the base of vein 7, at the point where it meets the discocellular vein. Due to the way the specimen is set we do not know the structure of the patch, but it is likely that it contain small yellow to white scales like the rest of the members of the ignobilis -group. The costal area of the hindwing is covered in light scales down to the area in space 6 just above vein 6. There is a small amount of dark hairs in space 1c and 1b in the basal part of the wing. Vein 1b is at most lightly inflated a few millimetres away from its base, and this part of the vein is lightly covered in darker hairs.

The ventral surface base colour is similar to the dorsal side, but with a more violet tone ( Fig. 23 ). There are two beige-purple bands extending across both wings so that a discal band of the ground colour is formed between them. On the forewing there are two additional light bands placed basally in the wing cell angled slightly towards the apex. The basal edge of the main inner light band and the distal marginal edge of the outer band gradually fade into the ground colour. The band is quite jagged on both sides and at the end of the cell on both wings there is a thin tooth like projection pointing downwards towards the mid margin. All eyespots on the ventral side are surrounded by a light halo of a similar colour to the light bands. This halo turns almost white immediately under the forewing apical patch. The ventral forewing has two well-developed eyespots with yellow-orange outer rings. The hindwing has a row of eight similar eyespots from space 1b up to space 6 (there are two spots in space 1c). The eyespot in space 2 is the largest and the spot in space 3 is very small.

Female description: Paratype forewing length 24.5 mm. The single female specimen ( Fig. 24 ) is rather worn, and therefore the colour is hard to accurately describe. It is most likely of a similar medium dark brown as other females in the ignobilis -group. The apical patch on the dorsal forewing is better developed than in the male and of an almost pure white colour. The apical eyespot is also much better developed with a more clearly visible yellow outer ring. The central white spot is very small. The spot in space 2, which is well developed on the ventral side, is marked on the dorsal side by dark shading, but without a white centre or any outer light ring. The hindwing is uniformly brown, except the costal area which is lighter close to the base of the wing. The hindwings of the paratype are quite damaged, but the margin appears to be somewhat concave at the point of space 2. It is possible that the intact wings would have had a slightly tailed appearance, with a more drawn out tonus compared to similar species. The ventral side is typical for the group and similar to the male, except being much lighter. The light outlines to the discal band and the halo around the eyespots are almost pure white. The light halo around the hindwing eyespots is very much broader than in the other known species in the group.

Diagnosis. B. vandeweghei is very similar to B. brakefieldi with the main character differences in their androconial arrangement. B. vandeweghei has a small hairpencil located basally in space 1b of the dorsal forewing, with hairs pointing in the direction of the wing margin ( Fig. 26 ). This type of androconial structure is not present in B. brakefieldi ( Fig. 18 ). However, a similar kind of brush (although better developed) is present in Bicyclus ottossoni ( Fig. 22 ), but the apical patch on the dorsal forewing is much smaller in this species. The female of B. vandeweghei is much harder to separate from B. brakefieldi . The paratype female of B. vandeweghei has a much more extensive diffuse light area around the eyespots on the ventral hindwing, and this character is probably sufficient to separate the females of these two species. We have not been able to investigate this trait in all specimens of the ignobilis -group, but no images, that we have available, of males and females from any other species show this trait. The holotype DNA has been sequenced, and it is distinctly different from all the other species in the group. The female paratype was separated by comparing the morphology of all the available specimens from the general geographic region of the collection site for the male holotype.

Distribution. The only two known records are from a small area in eastern Gabon and western Republic of Congo ( Fig. 29 ).

Etymology. This species is named after Gaël Ruboneka Vande weghe, who collected the holotype during fieldwork related to his impressive book about Gabon butterflies (Vande weghe 2010).

Comments. A large amount of material from Gabon was collected by Vande weghe during the fieldwork leading up to his book on Gabon butterflies (2010). We have seen very little material of the ignobilis -group from the region, and it is likely that some of the records listed in the above mentioned book belong to B. vandeweghei . Investigating Vande weghe’s reference collection would be of very high value to further work on many speciesgroups.

Figures

FIGURES 23 – 26. Bicyclus vandeweghei Brattström sp. nov. 23. Male holotype, Gabon (OB – ABRI – 0068). 24. Female paratype, Republic of Congo (OB – ABRI – 0143). 25. Male holotype genitalia, Gabon (OB – ABRI – 0068). 26. Androconial structures (OB –– ABRI – 0068): There is a small inconspicuous brush (encircled in white) in the basal area of space 1 b on the dorsal forewing (also present in B. ottossoni sp. nov.). The anal area is lightly covered in dark brown hairs and vein 1 b is only enlarged for a very small part of its length. Only the basal parts of the hindwing cell – brush is visible in this image as it is mainly covered by the forewing.

FIGURES 27 – 29. Distribution maps for the Bicyclus ignobilis species-group. Records of different species from the same site have been slightly offset when presented in the same map so that all species symbols can be clearly seen. Multiple records close to each other have been collapsed to a single point. The complete distributional data is available in Supplementary Table 1. 27 – 28. B. ignobilis (Open Squares) and B. maesseni (Open Crosses). 27. West Africa up to the Cameroonian border. 28. Cameroonian border and eastwards. 29. Remaining species occurring between Nigeria and Eastern DRC: B. brakefieldi (Filled Circles). B. ottossoni (Filled Crosses). B. rileyi (Open Circles). B. vandeweghei (Filled Diamonds).

FIGURES 30 – 36. Identification of females from the ignobilis- group. The images are not shown to scale, arrows indicate the main characters of importance for identification. 30. B. rileyi is much larger than any other species and the light markings in the apical patch continue below the eyespot in space 2, and often reach the lower margin of the wing. 31. B. maesseni has the edge of the apical patch more broken up in the area closest to the apical eyespot. Also, vein 4 is heavily marked with darker scales, breaking up the patch along its entire length. 32. B. ignobilis (western part of range) almost always lack the ventral hindwing spot in space 3, the apical patch is also much more solid than in B. maesseni with vein 4 just making a dark indentation in the basal part of the light patch. 33. B. ignobilis (eastern part of range) has vein 4 more heavily darkened so that the apical patch is sometimes fully broken up in sections. This makes them appear similar to B. maesseni, but the latter species is not sympatric in the eastern part of the range of B. ignobilis. The ventral discal band gradually gets a more pronounced edge at the end of the cell on both wings in a clinal fashion towards the east of the species range. 34. In B. ottossoni the basal part of the apical patch lacks indentations of dark scales along vein 4. The outer borders of the patch are much better defined than in the other species. The distal margin of the forewing is also much less convex, giving the wing a more squared shape. 35. B. vandeweghei have much more prominent light shading around the hindwing eyespots. The apical patch is otherwise similar to B. ignobilis. 36. B. brakefieldi have a more yellowish colour in the apical patch, and the part of the patch being placed basally of the eyespot is a bit fainter than in other species.

FIGURES 15 – 18. Bicyclus brakefieldi Brattström 2012. 15. Male, DRC (OB – ABRI – 0024). 16. Female, DRC (OB – ABRI – 1016). 17. Male genitalia, DRC (OB – ABRI – 0093). 18. Androconial structures (ABRI – 14 – 657): There is no well – defined brush in the basal area of space 1 b on the dorsal forewing (present in B. ottossoni sp. nov. and B. vandeweghei sp. nov.). The anal area of the hindwing is covered with dense shiny black hairs and the base colour is also darker in this region. Only the basal parts of the hindwing cell-brush is visible in the image as it is partly covered by the forewing.

FIGURES 19 – 22. Bicyclus ottossoni Brattström sp. nov. 19. Male paratype, Cameroon (OB – ABRI – 0077). 20. Female paratype, Cameroon (OB – ABRI – 1013). 21. Male paratype genitalia, Cameroon (OB – ABRI – 0077). 22. Androconial structures (OB – ABRI – 0077). There is a well-defined brush (encircled in white) in the basal area of space 1 b on the dorsal forewing (also present in B. vandeweghei sp. nov.). The anal area is partly covered by dense dark brown to black hairs and vein 1 b is slightly enlarged from close to its base up to about half of its length. Only the basal part of the hindwing cell-brush is visible as it is mainly covered by the forewing.