Introduction

Recent field activities developed in São Tomé e Príncipe by the senior co-author since 2004 allowed us: (i) to conclude that the population of Sevenia amulia (Cramer, 1777) (Nymphalidae) exclusively known in the country from Príncipe Island, is somewhat distinct from that of the nominate subspecies, as well as from specimens of S. amulia intermedia proceeding from Angola - it is, further, different from S. rosa, previously considered as one more subspecies of S. amulia; (ii) to identify two species that remained unknown in the country until now, a Lycaenidae (Polyommatinae) and a Nymphalidae (Heliconiinae); and (iii) to rectify the presence in São Tomé e Príncipe of one species of Hesperiidae (Hesperiinae) described nine decades ago. The aim of this contribution is therefor, to discuss the validity of Andronymus thomasiRiley, 1928 upon a female obtained in northern Príncipe; to describe one new subspecies of Sevenia amulia (Cramer, 1777) endemic from the same island; and to confirm from São Tomé the presence of Chilades trochylus (Freyer, 1844) (Lycaenidae) and of Acraea (Acraea) neobule Doubleday, Hewitson & Westwood, 1850 (Nymphalidae), both common throughout the Afrotropical Region but previously unknown in the country.

The last general contributions to the knowledge of the Papilionoidea of São Tomé e Príncipe are those of PYRCZ (1981, 1992) and of MENDES & BIVAR-DE-SOUSA (2012a, b). However, a deeper and global study of the butterflies and skippers of the country is close to completion.

Materials and methods

The following abbreviations will be used throughout the text: BM - The former British Museum (Natural History), now Natural History Museum, London, Great Britain; C - Central; CAR - Central African Republic; DRC - Democratic Republic of the Congo; Cu1 - First cubital vein; CZ - Former Centro de Zoologia of the IICT; D - Dorsal wing surface (recto); E - East, eastern; FW - Forewing; FWL - Forewing length; HW - Hindwing: IICT - Former Instituto de Investigação Científica Tropical, now integrated in the MUHNAC; LM - Collected by the senior author; M1 - First median vein; M2 - Second median vein; M3 - Third median vein; MUHNAC - Museu Nacional de História Natural e da Ciência, Lisbon University, Portugal; N - North, northern; PR - Príncipe Island; S - South, southern; SE - Southeast, south-eastern; ST - São Tomé Island; STPR - São Tomé e Príncipe (country): V - Ventral wing surface (verso).

All the studied specimens were net-collected by the senior author and are part of the entomological series of the CZ (IICT), now integrated in the MUHNAC - the registration numbers concern the sequence followed in the CZ collection. The samples are known from the localities listed below for which the administrative district (only one in PR) is reported and the approximate latitude, longitude, and altitude (in meters above sea level) are presented, based on the JIU (1961/1962 and 1962) maps.

The FWL was measured using an etalon clipper along the FW anterior border or costa, from its insertion on the thorax to apex. For the photos of the preserved specimens a Canon EOS-450D camera supported by a computer Macintosh iMac LED16:9 with a 27-inch widescreen was used. When necessary, the specimen study was performed under the stereomicroscopes Wild M5A and Leica M165C.

Taxonomy

HESPERIIDAE

HESPERIINAE

Genus Andronymus Holland, 1896

Andronymus thomasiRiley, 1928 (Figs. 2-3)

Andronymus thomasiRiley, 1928ª

Andronymus neander thomasiRiley, 1928. Evans, 1937, Bacelar, 1958; Ackery et al., 1995; Larsen, 2005; Williams, 2008; Mendes & Bivar-de-Sousa, 2012a; Mendes & Bivar-de-Sousa, 2012b.

Material examined: PR: Near Bombom, beginning of the road to the airport, western slope, 20-VI to 8-VII-2016, 1 ♀ (CZ-6024).

Andronymus thomasi was described from ST (RILEY, 1928) and later reported by EVANS (1937, as a subspecies of A. neander) from STPR (1 ♂, ST, 1 ♀, PR both noted as in the BM collection, the male being certainly the holotype); there are a few known references but the species was not again observed for almost nine decades. According to LARSEN (pers. comm.) at least the holotype remains in that Museum. Andronymus thomasi is endemic from STPR although its recent presence in the ST Island remains unconfirmed and its geographically detailed origin in this island is unknown.

The studied specimen (FWL: 18 mm) lacks as it is typical to the similar A. neander, the clear separation between whitish inner part of the HWV and its brownish border. It is the only Hesperiidae known in the country to show a large and conspicuous transparent white discal spot in the HW (Figs. 2-3). The brownish area of both wings D and V is darker than in A. neander, and in the present species there is (almost) no dark punctuation on the light area of the HWV and the marginal cilia are dark brown. The FW is somewhat distinct to that of A. neander (photos of East African specimens in KIELLAND, 1990; LARSEN, 1996), being shorter and apically less acute; the subapical spots of A. thomasi were reported as being three and smaller than those in A. neander. However, in the studied female there are only two subapical spots that are conspicuous, despite being quite small. Further, the white-translucent areas were described as being tinted with yellow, but in the Bombom specimen they are pure white.

The studied female was collected at the beginning of the gravana, still with rains; it comes from close to the limits of the Bombom Lodge in the extreme N Príncipe, from a ca. 10 m high steep forest slope and was perched on the green leaves at 1.5-1.7 m above the soil - no flowering plants were present around (Fig. 1). A. neander, which is known throughout most of sub-Saharan Africa except for parts of South Africa, seems to occur in forest, forest-savanna transition and gallery-forest. Nothing is known about the STPR immature stages although the caterpillars of the mainland African species reportedly feed on Fabaceae (Brachystegia) and on Malpighiaceae. However, Brachystegia is not present in STPR and the Malpighiaceae are rare and poorly diverse in the country (EXELL, 1944; FIGUEIREDO et al., 2011) which suggests possibly distinct insular host-plants for A. thomasi.

LYCAENIDAE

POLYOMMATINAE

Genus Chilades Moore, 1881

Chilades trochylus (Freyer, 1844) (Figs. 4-5)

Material examined: ST: Morro Peixe, 9-IX to 24-IX-2015, 1 ♂ (CZ-5968); Id, 12-VII-2016, 3 ♂♂, 1 ♀ (CZ-6027). All the specimens were collected between 10.00 and 12.00 h.

Chilades trochylus is easy to recognize taking into account its minute size - FWL: ♂: 7.5-8 mm; ♀: 9 mm - being the smallest butterfly in the country and one of the smallest Afrotropical species. It is also distinctive due to its bluish brown D and the orange-red anal marginal band on the HWD, enclosing three small black spots; this area also exists on the HWV where the black scales of the spots are mixed with numerous others, bright metallic green (Figs. 4-5). STEMPFFER (1967, under Freyeria) figure the male genitalia.

The species is known throughout Africa, SE Europe, Near East and Arabia mainly in open, exposed areas, and more rarely along forest pathways. It is now reported for the first time from ST and for the country, where it appears to be localized in the NW drier area of the island. The species is apparently rare in STPR, but the much reduced wingspan of the imagos may have contributed to the fact that it has been previously overlooked. It is often considered to include the genus Freyeria Courvoisier, 1920, presently placed in the Chilades synonymy (LARSEN, 2005).

The studied specimens were all collected among more or less dry Gramineae and Leguminosae in the road verges, close to cultivated areas - mainly with maize and cassava; they flew slowly and very low, no more than 20-30 cm above the herbs. No other specimens were observed despite the Morro Peixe area being prospected throughout the year (the last time during the end of January 2017).

The caterpillars (never locally observed) are known to feed on Indigofera (Fabaceae) and Heliotropium (Boraginaceae), both genera with species occurring in STPR (FIGUEIREDO et al., 2011). They are usually attended by Pheidole worker ants (Myrmicidae).

NYMPHALIDAE

BIBLIDINAE

Sevenia Koçac, 1996

Sevenia amulia principensis Mendes & Bivar de Sousa, ssp. n. (Figs. 6-7)

Crenis amulia Cramer, 1777. Bacelar, 1958

Sallya amulia (Cramer, 1777). Pyrcz, 1991

Sallya amulia amulia (Cramer, 1777). Pyrcz, 1992

Sevenia amulia amulia (Cramer, 1777). Mendes & Bivar-de-Sousa, 2012a, 2012b

Material examined: Type material: Holotype ♀ (CZ-6053): PR: Porto Real, 25-I-2017, 10-11.30 h. Paratype: PR: Id, 21-I-2016, one specimen without abdomen (CZ-6009) - also collected in midmorning. Non-type specimen: PR: Airport, 12-X-1955, coll. Décio de Passos, a not well preserved ♀ (CZ-2422).

Description: Female. FWL: 27-29 mm, the specimen without abdomen: 24 mm. D and V as in figures 6 and 7, quite unique among the STPR butterfly species. D is brown with some irregular and indistinct FW darker maculation, mainly a dark irregular spot on the cell apex, and with a very weak, violaceous sheen; one complete row of submarginal dark spots are present on the HW. V is orange and alternated with thin bluish-gray bands and small black markings encircled by light bluish-gray in the HW; additionally there is a row of black submarginal spots in all four wings. FWV with one blackishbrown round spot in the pre-apical area and three small dark brown spots in spaces M₁-M₂, M₂-M₃ and M₃-Cu₁. The male remains unknown.

Biotope: Forest trails margins.

Discussion: Two subspecies of S. amulia (Cramer, 1777) are presently known. The nominate one, assigned from Ghana, Nigeria, Cameroon, Gabon, Congo, CAR and C and N DRC, whose type-locality was reported as Sierra Leone (false-locality after LARSEN, 1996); and S. amulia intermedia (Carcason, 1961), described from the “Katanga” (Shaba) and also known from other DRC provinces (Lualaba, Lomami, Maniema and Sankuru), Angola, N Zambia and (vagrant?) Botswana. When compared with S. amulia intermedia (Figs. 8-9) - material from Angola (Kwanza Sul, Malanje and Bié), was used for comparison - S. amulia principensis ssp. n. shows almost no violaceous sheen, being more dark Brown than violet. It also has small but quite conspicuous dark spots on the median and medio-cubital spaces of the FWV, which are absent or quite diminished in the remaining subspecies; further, the post-median row of HWV spots is more distant from the wing’ border than in S. amulia intermedia. S. rosa (Hewitson, 1877), described from S Mozambique (Delagoa Bay, currently Maputo Bay), known from woodland and forest margins in Kenya (migrant?), E Tanzania, Malawi, Zambia, E Zimbabwe, Botswana, Namibia (Caprivi strip) and South Africa (KwaZulu-Natal) was also considered a subspecies of S. amulia - see ACKERY et al. (1995) - but is now accepted as a valid species. It is much lighter and more violaceousthan S. amulia and has a much strongly marked D, mainly in the female (Figs. 10-11); further, it shares with S. amulia amulia and with S. amulia intermedia the reduced dark maculation on the FWV, allowing its prompt diagnosis relatively to the new S. amulia principensis.

Preliminary DNA barcoding results based on the CO₁, revealed no significant differences between S. amulia intermedia from Angola (Malanje) and the PR types (not published). Based on the registered morphological dissimilarities, the PR specimens are, however, considered to belong to a new subspecies despite the inconclusive genetic analyses and the absence of information on the male genitalia morphology.

Host-plants: PYRCZ (1991) reports he saw oviposition on Cola sp. (Sterculiaceae) at Terreiro Velho, in the extreme S of the island. This is likely to constitute the subspecies’ food-plant in the PR. In continental Africa, Maprounea, Sapium and Shirakiopsis (Euphorbiaceae) are considered to be the host-plants of the known subspecies (ANONYMOUS 2017, D’ABRERA, 2004, LARSEN, 1996, 2005) but all these genera remain unknown in STPR (FIGUEIREDO et al., 2011).

Notes: An additional specimen was observed on the wing the January 2017, which together with the reduced number of specimens collected, points to a quite uncommon taxon eventually restricted to the “gravanito”, the small dry season. Relatively to PYRCZ (1991) reference to the Terreiro Velho, no date is provided for the observation.

Etymology: The subspecies is named after the PR, the only island from where it remains known and from where it is likely endemic.

HELICONIINAE

Acraea Fabricius, 1807

Acraea (Acraea) neobule Doubleday, Hewitson & Westwood, 1850 (Figs. 12-16)

Material examined: ST: Morro Peixe, 18-IX-2014, 3 ♂♂, 1 ♀ (CZ-5939); Id, 25-VI-2015, 7 ♂♂, 2 ♀♀ (CZ-5960); Id, 19-IX to 24-IX-2015, 1 ♀ (CZ-5968); Id, 09-II-2016, 1 ♂ (CZ-6016); Id, 12- VII-2016, 5 ♂♂, 1 ♀ (CZ-6027). Ribeira Funda, 25-VI-2015, 2 ♂♂, 1 ♀ (CZ-5959); Id, 10-II-2016, 1 ♂, 4 ♀♀ (CZ-6017). Água Izé, 14-VII-2016, 1 ♂ (CZ-6034). All the specimens were collected midmorning, between 10.00 and 12.00 h.

The FW length is 25-30 mm, with that of the female often being slightly larger. The species, known from the Afrotropical Region, S Arabia included, is somewhat variable which led to the description of several suspecies, presently considered as lacking validity. It is, however, quite distinctive and impossible to mistake with any other Acraea from STPR due to the apically vitreous FW with some inconspicuous marginal intervein orange markings and to the existence of marginal lunules on the HW (Figs. 12-16). The FW base and the whole HW ground-colour is deep orange in the males and lighter orange-ochre or greyish in the females. There are several black dots on the FWD, and on both the HW surfaces, which are variably developed but usually larger in the females; one of them is a cell-spot, another exists at the cell apex. The HWD has a wide black margin usually containing orange round dots, almost indistinct in the darker specimens. In the basal HWV there are 2-3 black and white contrasting spots, distinct, however, from the “chequered” basal area of the larger A. (Acraea) zetes annobona D’Abrera, 1980, a common and widely distributed species known all along ST and PR.

A. neobule is new for ST and STPR and is known from open habitats and degraded areas, including road verges and agricultural areas, but it does not enter forest. In the Morro Peixe area it is not uncommon in the drier seasons, the gravana (June to August/September) and the gravanito (January/February). In the course of our last visit to the area, in January 2017, no specimen was collected or even seen. In Ribeira Funda it was found mud-puddling (especially males) on the salt mud close to the sea. It is likely to occur sporadically in the eastern coast, since only 11was obtained in Água Izé, where A. zetes annobona is the dominant Acraea throughout the year. It was considered a synonym of the Oriental A. terpsicore, though their complete independence is presently fully accepted (LARSEN, 1996).

The known host-plants are Adenia, Passiflora, Tryphostemma (Passifloraceae), Hybanthus (Violaceae) Corchorus (Tiliaceae) and Barleria (Flacourtiaceae); two species of Adenia, three of Passiflora and two of Corchorus are known in STPR (FIGUEIREDO et al., 2011).

Acknowledgements

First of all, we would like to thank the Regional Government of the Príncipe in the person of its President, Engº José Cassandra, for the attention dedicated to the work we have developed in this island and in the country. We also thank the following colleagues and friends: Dominique Bernaud, from Papeete, Tahiti, specialist in the Acraea butterflies, who confirmed the identity of the ST species; Cristiane Silveira and Luis Filipe Lopes, from the MUHNAC, for the CO1 analyses performed in several butterfly species, one PR Sevenia specimen included. We are, further, deeply indebted to the HBD Tourism Investments, directly to Philippe Moreau and to the Omali (ST) and Bombom (PR) directors, José Miguel Mendes and Sérgio Duarte, for the continual interest and provision of facilities particularly during our most recent stays in the country; to Estrela Matilde of the Príncipe Trust Foundation, for her friendship and the discussions on the biodiversity of São Tomé e Príncipe; and to Ruben Fortuna, the Bombom eco-guide, an excellent companion during part of the field-work conducted in the Príncipe, specifically in the Porto Real area. SV was funded by the Portuguese Science and Technology Foundation (FCT) through grant SFRH/BI/51643/2011.

BIBLIOGRAPHY

ACKERY, P. R., SMITH, C. R. & VANE-WRIGHT, R. I., 1995.- Carcasson’s African Butterflies. An Annotated Catalogue of the Papilionoidea and Hesperioidea of the Afrotropical Region: i-xii + 803 pp. CSIRO, Victoria.

ANONYMOUS, 2017.- Available from www.metamorphosis.org.za/.../177%20Genus%20Sevenia%20Kocak.pdf(accessed14thFebruary2017).

BACELAR, A., 1958.- Alguns Lepidópteros da África Ocidental portuguesa (Colecção do Museu Bocage).- Revista Portuguesa de Zoologia e Biologia Geral, 1(4): 311-330.

D’ABRERA, B., 2004.- Butterflies of the Afrotropical Region. Part II. Nymphalidae, Libytheidae: i-xli + 258- 539, plates with text. Hill House Publisher. Melbourne/London.

EVANS, W. H., 1937.- A Catalogue of the African Hesperiidae Indicating the Classification and Nomenclature adopted in the British Museum: 212 pp + 30 pls.

EXELL, A. W., 1944.- Catalogue of the vascular plants of S. Tomé (with Principe and Annobon): 428 pp. British Museum (Natural History), London.

FIGUEIREDO, E., PAIVA, J., STÉVARY, T., OLIVEIRA, F. & SMITH, G. F., 2011.- Annotated catalogue of the flowering plants of São Tomé e Príncipe.- Bothalia, 41(1): 41-82.

JIU-JUNTA DE INVESTIGAÇÕES DO ULTRAMAR, 1961-1962.- Carta de São Tomé, levantamento aerofotogramétrico: 4 folhas, escala 1:25000.

JIU-JUNTA DE INVESTIGAÇÕES DO ULTRAMAR, 1962.- Carta do Príncipe, levantamento aerofotogramétrico: 2 folhas, escala 1:25000.

LARSEN, T. B., 1996.- The Butterflies of Kenya and their Natural History: 500 pp. Oxford University Press, Oxford.

LARSEN, T. B., 2005.- Butterflies of West Africa: 595 pp. Apollo Books, Stenstrup.

MENDES, L. F. & BIVAR-DE-SOUSA, A., 2012a.- Riqueza de espécies e endemicidade das borboletas diurnas (Lepidoptera: Rhopalocera) em São Tomé e Príncipe.- Actas do Colóquio Internacional “São Tomé e Príncipe numa perspectiva interdisciplinar, diacrónica e sincróniaca”: 653-663.

MENDES, L. F. & BIVAR DE SOUSA, A., 2012b.- New account on the butterflies (Lepidoptera: Rhopalocera) from São Tomé e Príncipe.- Boletín de la Sociedad Entomológica Aragonesa, 51: 157-186.

PYRCZ, T., 1991.- Account of two expeditions to São Tome and Principe and description of two new ssp. Of Acraeidae.- Lambillionea, 91(4): 362-374.

PYRCZ, T., 1992.- Provisional check-list of the butterflies of São Tome and Principe Islands.- Lambillionea, 92: 48-52.

RILEY, N. D., 1928.- List of the species collected in the island of São Thomé by T. A. Barns.- The Entomologist, 61: 64-65.

STEMPFFER, H., 1967.- The genera of the African Lycaenidae (Lepidoptera: Rhopalocera).- Bulletin of the British Museum (Natural History). Entomology. Suppl., 10: 1-322.

WILLIAMS, M. C., 2008.- Butterflies and Skippers of the Afrotropical Region (Papilionoidea and Hesperioidea).- An Encyclopedia. © seventh ed. (accessed last time the 10th May 2017).