Description of previously unknown females of three Euriphene Boisduval, 1847 species and the unknown male of Bebearia inepta Hecq, 2001 from Western Africa, with notes on their taxonomy, bionomy and distribution (Lepidoptera: Nymphalidae, Limenitidinae)

Descripción de las hembras de tres especies, antes desconocidas, de Euriphene Boisduval, 1847 y del macho desconocido de Bebearia inepta Hecq, 2001 de África Occidental, con notas sobre su bionomía y distribución (Lepidoptera: Nymphalidae, Limenitidinae)

Introduction

In recent years, research on fruit-feeding Lepidoptera (mainly Charaxinae, Satyrinae and Limenitidinae) has been intensified in tropical areas, including western Africa. One of the main reasons for this was the publication of Torben Larsen’s comprehensive work on the West African Lepidoptera (LARSEN, 2005), which is now used as a foundation for both taxonomic and ecological research in the region. The second and third authors were involved in various research projects in West African forests since 1974, while the other authors between 2006 and 2018, during which an extensive material of fruit-feeding butterflies (particularly Limenitidinae, Adoliadini) was collected in Western Cameroon, Ghana, Guinea, Ivory Coast, Liberia and Sierra Leone.

In the material collected during these research projects, previously unknown sexes of a few recently described species in the genera Euriphene and Bebearia were recognised: females of Euriphene lomaensis Belcastro, 1986, E. taigola Sáfián & Warren-Gash, 2009, and E. bernaudi Hecq, 1994, and males of Bebearia inepta Hecq, 2001. This paper aims to present morphological descriptions and illustrations of the previously unknown sexes. It also provides further information on the habitats, distribution and biogeography of these poorly known species.

Methods

Euriphene taigola, E. lomaensis and Bebearia inepta were observed and collected on various field expeditions in Sierra Leone during over ten field trips to the Gola Forests between 1989 and 2017 by Claudio Belcastro, specimens were also collected in Sierra Leone and Liberia between 2010 and 2017 by Szabolcs Sáfián, Robert Tropek, Oskar Brattström; a few specimens collected in Diecké Forest, Guinea, by C. Belcastro and local collectors were also examined. Female specimens of E. bernaudi were first collected by the African Butterfly Research Institute, (ABRI) collectors in 2010 and 2011 and during an expedition organized by Marianne Espeland, Robert Tropek and Szabolcs Sáfián in the Cameroon Highlands in April 2013.

For comparison of the newly described sexes and their respective relatives, we consulted the Rhopalocera collection of the African Butterfly Institute, Nairobi, Kenya (ABRI) and the research reference collections of Claudio Belcastro, Szabolcs Sáfián and Oskar Brattström. In the descriptions we followed the English numbering of wing venation, as described in MILLER (1970). Sáfián’s research reference collection is now deposited at the African Natural History Research Trust’s (ANHRT) Museum in Leominster, UK.

Descriptions

Euriphene lomaensis Belcastro, 1986

The species was described from a male holotype collected in the Loma Mountains, Sierra Leone, (BELCASTRO, 1986) and was originally believed to be endemic to the area, until another male was found in the Taï National Park, western Ivory Coast (LARSEN, 2005). Recently, further males and the first female of the species were obtained in the lowland forests of the Gola Rainforest National Park, Sierra Leone (BELCASTRO & LARSEN, 2006). Oskar Brattström found the first specimens for Liberia in the Sapo National Park, including the second female. Another female was found in the Sapo National Park by Robert Tropek and Szabolcs Sáfián and subsequently, the species was also recorded (both males and females) from the Liberian side of the Nimba Mountains on various occasions, where it seems to be generally more common. No specimens have been found outside the Liberian sub-region so far. The species were found both in lowland and upland and even sub-montane forest within its range, but it appeared only in primary or old grown secondary forest with closed canopy. Males were observed expressing display behaviour on hilltops in the Nimba Mountain, possibly because abundance of the populations is generally low. On some occasions both males and females were captured in fruit- baited net-traps set close to the ground.

Description of female: Illustrated specimen data: SIERRA LEONE, Gola North, Lalehun 1-V-2013, leg. Belcastro, (Fig. 1 A, B); Liberia, Sapo National Park, Putu Jawodee 26-XI-09-XII-2009, leg. Oskar Brattström (Fig. 1 C, D).

Forewing: 31-33 mm, wingspan: 54-57 mm (between the specimens illustrated). The female is of “Catuna-type” with unusually falcate forewing outer margin and acute apex. The ground colour is brown with creamy yellow pattern. The pale-yellow lines and spotting on the forewing are inconspicuous looking rather shades of the pattern itself. The central transverse band on the forewing is also very weakly marked and narrow (much more conspicuous on the underside) but the four whitish spots in the apex are visible. The hindwing upper side has a prominent creamy transverse band, broadening significantly from the abdominal fold towards the apex (4 mm in space 1b and 11 mm in space 6). The underside is similar in both colour and pattern to the upper side but is generally lighter, the pattern is more conspicuous, and the hindwing’s creamy-yellow area and the forewing’s sub-apical area are sparsely speckled with dark brown scales. There is a prominent pale yellowish spot in the hindwing base and another more irregular pale-yellow area centred on the base of the hindwing cell.

The female of E. lomaensis is not easily recognizable in the wild, being very similar to the female of E. coerulea. It was considered quite different by T. Larsen, because the presumably closely related Central African E. karschi has a very different, typical ‘Euriphene-type’ female with uniformly reddish-brown ground colour, black apical area with a prominent white subapical band and four white spots in the forewing apex. However, despite its similarity to the female of E. coerulea (1 E, F), the falcate outer margin of the forewing with a rather acute apex, the hindwing underside with the pale yellowish basal spot and the pale creamy yellow outer half, speckled with brown scales are convincing features to pair it up with the male E. lomaensis. Other Euriphene species related to E. lomaensis (e. g., E. obsoleta) have very similar wing shape and underside pattern.

Other material examined: GUINEA: 1 ♀, Guinea, Fôret Classée de Diecké, VI-2012 (leg. local collector, coll. C. Belcastro); LIBERIA: 1 ♀, Grand Gedeh County, Sapo NP, Gamboh trail, 15-20-XI- 2012 (leg. R. Tropek and Sz. Sáfián, coll. Sz. Sáfián); 1 ♀, Grand Gedeh County, Putu Jawodee, buffer zone to Sapo National Park, 26-XI-8-XII-2009 (leg. O. Brattström, coll. ABRI) (Fig. 1 C, D); SIERRA LEONE: 2 ♀♀, Gola Forests (South and North), 11-12-V-2011 (leg. and coll. C. Belcastro);

Euriphene taigola Sáfián & Warren-Gash, 2009

The first (male) specimens of this recently described species were found in the Taï National Park, western Ivory Coast, by Haydon Warren-Gash, who was hesitant to describe it until more morphologically identical males were collected in the Gola Rainforest National Park, Sierra Leone (LARSEN et al., 2009). The species was believed to be rare and local, but extensive field studies in the Gola Forests in Sierra Leone and Liberia and other forest areas in Liberia revealed that E. taigola is not necessarily rare, but its distribution is probably centred in Liberia’s generally under-recorded lowland forests. There, it is relatively widespread and could be occasionally common. The species is associated with hyper-wet and wet forests in good conditions, none were found in the submontane forests of Nimba Mountains, Liberia, while specimens were recorded from the lowland zone at the foothills of the Liberian Nimba and in the lowland forest of Diecké in Guinea near the Nimba Mountains. Males were observed displaying on hilltops and both sexes were found in fruit-baited traps.

Description of female: Illustrated specimen data: SIERRA LEONE, Gola North, Lalehun forest trail. 5-V-2014 (leg. and coll. C. Belcastro) (Fig. 2A, B).

Forewing: 29 mm, wingspan: 52.5 mm. The upper side is of typical ‘Euriphene-type’ with blackish brown ground colour in the outer half of the forewing, warmer brown in the inner half of the forewing and the hindwing and with a prominent whitish sub-apical band on the forewing. The band is unbroken, it tapers down strongly towards the costa from vein 4 at the end of the discoidal cell, where its outer edge is also strongly serrated. The spot in space between veins 3 and 4 is at least twice as large as those above it. The crescent shaped spot between veins 2 and 3 is partially conjoined. There are four small white subapical dots in the spaces between veins 4 and 9. On the hindwing upper side there is a row of sub-marginal crescent-shaped dark brown lunules and another one with conical spots towards the centre, with lighter spots in-between. A fine dark median line is also visible, and the margin is also sparsely covered with darker scales. The underside ground colour is warm hazel brown with the prominent sub-apical band on the forewing and the four white dots of the upper side, a white dusted black centre spot on the hindwing and prominent whitish pattern and scaling. The white scaling is particularly visible in centre area of the hindwing, where a quadrangular area is well edged by a White band that runs from the inner margin through the blackish central spot, where it turns in right angle upwards to the costa. Apart from this central quadrangle, there are also whitish spots overlaid in the discoidal cell and a larger whitish area in the tornus. The post-median row of lunules and the spots of the upper side also appear as whitish spots. Further white pattern appears in the forewing discoidal cell and a prominent whitish spot at the tornus, adjacent to the end of the white sub-apical band. Many West African Euriphene females are similar in appearance, however, the female of E. taigola could easily be separated from all but that of E. aridatha feronia via the white-barred quadrangle on the hindwing underside which is characteristic only of E. taigola and E. aridatha feronia in West Africa. The separation of E. taigola from E. aridatha feronia is particularly difficult for inexperienced eyes, but the white sub-apical band tapers down towards the costa in E. taigola (Fig. 2 A, B), while it is generally of even width in E. aridatha feronia (Fig. 2 C, D).

Other material examined: GUINEA, 1 ♀, Fôret Classée de Diecké, VI-2012 (leg. local collector, coll. C. Belcastro); LIBERIA, 1 ♀, Nimba Mountains, Western Range, Vanyenpah, Gba Community Forest, 20-27-II-2012 (leg. Sz. Sáfián and M. Strausz, coll. ANHRT); 8 ♀♀, Gola Forests (South and North), various dates in 2013-2015 (leg. and coll. C. Belcastro); SIERRA LEONE, 1 ♀, Gola North, Lalehun, (1-IV-XII-2008 (leg. Sz. Sáfián, G. Csontos and R. Vorgas; coll. ANHRT).

Euriphene bernaudi Hecq, 1994, stat. n.

The butterfly was described as a subspecies of E. simplex (Staudinger, 1891) by HECQ (1994) but was already treated as a distinct species by HECQ (2002) and subsequently also by LARSEN (2005). Despite the obvious morphological and ecological differences between E. simplex and its sub-species, E. bernaudi was not formally raised to species level, as pointed out by WILLIAMS (2017), which here we correct. The male of E. simplex is morphologically very distant from E. bernaudi, since it is one of the few species, where the blue colour completely overlays the usual Euriphene pattern, whereas on males of B. bernaudi the pattern is clearly visible. E. bernaudi is also significantly larger in size (the species is one of the largest Euriphene) based on the series examined in the ABRI collection and the real-size illustration of the holotype in HECQ (2002). E. simplex is a widely distributed lowland species of the Upper Guinean forest zone, whereas E. bernaudi is a Gulf of Guinea Highlands endemic orophilous specialist, which does not commonly occur below 1500 m asl. (LARSEN, 2005). For these differences the two cannot be treated conspecific (stat. n.).

The male was first collected on the Obudu Plateau, Eastern Nigeria, by St. Leger in 1965 and then on a few occasions by several collectors (LARSEN, 2005; Robert Warren, pers. comm.), and later in its type locality in the Rumpi Hills, Cameroon, by D. Bernaud (HECQ, 1994). Quite a few specimens, including females, were found recently on Mount Kupe in Cameroon by ABRI collectors in 2010-2011, and by Szabolcs Sáfián, Robert Tropek and Marianne Espeland in 2013.

Description of female: Illustrated specimen data: CAMEROON, South-Western Province, Mount Kupe (Koupé), 2010-2011 (leg. and coll. ABRI) (Fig. 3A, B).

Forewing: 40.5 mm, wingspan 73.5 mm, significantly larger than the majority of species in the genus, even compared to its morphologically closest relatives (E. jacksoni, E. hecqi) (Fig 3. A, B). It is of the typical ‘Euriphene-type’, with dark apical area on the forewing and a white sub-apical band, although the ground colour is reddish-brown instead of hazel or light chocolate br