Bebearia wojtusiaki Sáfián, Brattström & Pyrcz, 2016

Sáfián, Szabolcs, Pyrcz, Tomasz & Brattström, Oskar, 2016, Two new species of Bebearia Hemming, 1960, as further evidence of centre of endemism of butterflies in Western Nigeria (Lepidoptera: Nymphalidae: Limenitinae), Zootaxa 4175 (5), pp. 449-462 : 456-459

Bebearia wojtusiaki Sáfián, Brattström & Pyrcz sp. nov.

FIGS.: 6A, D; 7A; 8A, D; 9A; 10

Holotype: ♂ NIGERIA, Ologbo, South of Benin City, Edo State 22.XI.2010. leg.: Oskar Brattström Coordinates : 6°1'2.94"N, 5°32'26.76"E. Elevation: 22 m asl. Gen. prep.: OB-BEB-003. Deposited in the ABRI collection.

Paratypes: 8♂♂ 7♀♀ NIGERIA, Okomu Forest , Bendel State: 1♂ : IX.1983; 1♂: no date; 1♂: 14.XII.1985; 1♂: 18.X.1984; 1♂: 20.XI.1984; 1♂: 14.II.1986; 2♂: 19.X.1984; 1♂: 20.X.1984 ;; 1♂: 18.X.1984; 2♂: 14.XII.1985; 3♀: no date; 2♀: 20.X.1984; 1♀: 13.II.1986; 1♀: 19.X.1984; 1♀: 14.XII.1985, all leg.: Janusz Wojtusiak 1♀: 8-9.I.2000, leg.: Tomasz Pyrcz; 1♂ NIGERIA, Okomu Forest , Bendel State 25.V.1984 gen . prep.: MZUJ-JL-155; 1♂ NIGERIA, Okomu Forest , Bendel State 15. XII. 1985 gen . prep.: MZUJ-JL-151; 1♀ NIGERIA, Okomu Forest , Bendel State, no date, leg.: Janusz Wojtusiak gen. prep.: MZUJ-JL-01/ 09.05.2014 ; 5♂♂ 3♀♀ NIGERIA, Ologbo Forest , South of Benin City , Edo State 19-24.XI.2010 Leg.: Oskar Brattström; ♀ NIGERIA, Ologbo Forest , South of Benin City , Edo State 26.III.2009 Leg.: Oskar Brattström; 1♀ NIGERIA , Lagos VIII. 1954. leg.: John Patrick Boorman, 1♀ NIGERIA, Omo Forest , Ogun State V. 2002. leg.: Robert David Warren. Deposited in the ABRI, MZUJ, BMNH and UMZC collections.

Other material examined: 1♂ NIGERIA , Eastern Nigeria Leg.: Frank Davey, could be Uzuakoli , Delta State (Libert pers. comm.), 1♀ NIGERIA (sine locus et anno) both ABRI collection . 3♂♂, 1♀ NIGERIA, Cornes-Riley collection collected possibly in the vicinity of Lagos (deposited in NNM)(from photographs by Robert Warren) , 1♂ NIGERIA, Lagos , 1♀ NIGERIA, Olokemeji (deposited in the BMNH)(from photographs by Torben Larsen).

Description of the holotype. Forewing length: 37 mm. Wingspan: 65.5 mm. The upperside ground colour is dark chestnut-red, but the apical half of the wing is black (covering just over half of the wing, as a triangle from the apex to the discoidal cell along the costa and the tornus. There are two rows of bluish-white spots along the outer margin in the black area from space 1b to the apex. Two well defined white rectangular spots are found in spaces 5 and 6 (respectively). The forewing apical black area has an intense iridescent blue reflection, best visible in direct sun or in strong artificial illumination. The hindwing is dominated by the chestnut-red ground colour, which is slightly darker in the marginal area, with a dark undulating sub-marginal line. The underside is light hazel-brown with the shades of the white spots in spaces 5 and 6 on the upperside showing through, and two blackish spots in spaces 4 and 5, as well as a small ill-defined black dot in space 8 near the apex. The usual “ Bebearia ” pattern is also visible as a figure-of-eight spot and other amoeboid patches in the discoidal cell and irregular lines in the median and post-median area of both wings, as well as a tiny black ring in the hindwing cell. The body is strong and bold, black on the underside with a whitish band on the abdomen and a couple of whitish lateral spots. The body colour is light hazel-brown on the upperside, the same tone as the wings. The antennae are long (21 mm), with a black shaft and three-fourth of the club is light hazel-brown.

Male genitalia. As normal for Bebearia , the genitalia are rather large (2.1 mm dorsoventrally and 2.3 mm laterally) and strongly sclerotised. The tegumen is rather broad and T-shaped on the lateral view, curving evenly below to the anterior tip. The uncus is longer than the tegumen and gently curving downward, strongly resembling a renaissance carnival mask with a long, bird-bill shaped structure. The gnathos is twin-lobed, the lobes are slender, gently curved and almost as long as the uncus, unusually turning down parallel to the stem of the tegumen. The valvae are rather long, fan-shaped, and are without projections. They are slightly bent upwards and their tips are evenly rounded. The valvae are only sparsely covered with short setae. The saccus is small and gently curved upwards with a narrow and rounded tip. The aedeagus is rather short and broad, narrower at the anterior end as the posterior tip is broad and rectangular. A downward curving cornutus is visible in the vesica (not everted). It is half as long as the aedeagus.

Description of female. Forewing length: 49 mm. Wingspan: 84 mm. Antennal length: 23.5 mm. The appearance of the female is very similar to that of the male, although the size difference between the sexes is substantial. The white spotting in the outer half of the forewing is conspicuous and the spots form a narrow, but obvious white band in the spaces between veins 4 and 7. The outer margin of the forewing is concave, making the forewing apex rather acute. The hindwing is evenly rounded from the apex to the tornus. There are two, rather illdefined whitish spots in the hindwing apex, both missing in the male. The underside colour and pattern is identical to that of the male.

Female genitalia. The papillae anales are prominent and are covered with rather dense hair. The apophyses posteriores are long and think. The von Siebold’s organ is medium sized, weakly sclerotized. The ductus bursae is very narrow, and straight, the bursa copulatrix is rounded.

Diagnosis. B. wojtusiaki , at first impression, resembles a slightly darker and well spotted B. plistonax . However, it is instead a morphologically intermediate species between B. plistonax and B. arcadius , as the red colour on the upperside is always slightly darker than on B. plistonax and similarly dark to, or only slightly lighter than B. arcadius . The bluish-white spotting on the forewing of B. wojtusiaki is always more bluish than B. plistonax , as the blue iridescent sheen, similarly to B. arcadius , is more extensive on B. wojtusiaki , and is not restricted just to the close environment of the whitish spots, which is usually the case in B. plistonax (apart from certain specimens from Zambia). The bluish-white spotting is also more extensive in B. wojtusiaki which always has two spots in the space between veins 1 and 2, three between 3 and 4, also three between 4 and 5, the inner ones being rather ill-defined. In females there is always a bluish-white, rather undefined spot at the end of the discoidal cell, visible as bluish-white shading on the males. B. plistonax in most cases have a single whitish spot between veins 1 and 2, a very ill-defined bluish-white spot can occur in space between veins 1 and 2 but it was found only on females from Central Africa, Uganda and Tanzania populations, and only a single male was found with an additional ill-defined bluish-white spot in the spaces between veins 1 and 2 in the series of examined specimens in the ABRI collection from Northern Zambia (among 17 males). The structure of the male genitalia is very similar in all three species, and dissection of multiple specimens from different localities revealed high individual variation and overlap of multiple features between them. We therefore consider male genitalia as lacking diagnostic value in discerning the three species. However, we found morphologically small, but significant differences in the structure of female genitalia with regards to the shape of ductus bursae, which is straight and considerably thinner in B. wojtusiaki , not gently bent before opening into corpus bursae as in B. plistonax and B. arcadius . The bursa copulatrix is sphere-shaped, while it is more oval or pear-shaped in the related species.

Discussion. The differences between the eastern Nigerian B. plistonax and B. wojtusiaki in western Nigeria were initially recognised over thirty years ago by the late Prof. Janusz Wojtusiak, who collected extensively in Nigeria between 1982 and 1986. However, he hesitated to describe the taxon from the limited material available at that time, maybe believing that the differences between the two populations would not prove sufficient enough to justify the separation of the western Nigerian populations from typical B. plistonax . In the last two decades, knowledge about the fauna and biogeography of West African butterflies has improved significantly, and western Nigeria is now beginning to be recognised as a distinct biogeographic sub-region, harbouring significant level of endemism and playing a role of a linkage between the more Central Africa-related Cross River loop and the forests west of the Dahomey Gap. We found that the morphological differences between B. plistonax , B. arcadius and B. wojtusiaki are stable on a geographical scale and there is no evidence for clinal patterns. Furthermore, morphological characters of B. wojtusiaki do not justify its placement as a subspecies of either. Thus, despite no apparent geographical overlap we consider that the three should be treated as distinct species.

Etymology. We gratefully pay tribute to the late Prof. Janusz Wojtusiak, who studied Nigerian butterflies between 1982 and 1986, by naming this species in his honour. He was the first known person to recognize that the western Nigerian ‘ B. plistonax ’ differed from the ones found east of the Cross River.