Boletim da SOCIEDADE PORTUGUESA ENTOMOLOGIA de Vol. VII-14 Bolm Soc. Port. Ent. n" 196 THE IBERIAN Leptothorax Mayr,1855 (HYMENOPTERA, FORMICIDAE) DISCOVERY OF A NEW SPECIES AND : FIRST RECORD OF L atlantis Santschi, 1911 JEAN-MARC BENIN' MARIAR.PAIVA^ C.A.COLLINGWOOD^ Abstract : A new species of the genus Leptothorax Mayr 1855, was discovered during a partial survey of the ant fauna, conducted in pine stands across the coastal area ofthe Peninsula of Setiibal, Portugal. Another species ofthe same genus, L. a//aA7fo Santschi 1911, was recorded for the firsttime in Europe. Both specieswere found in sites with sandy soils and in areas subjected to moderate anthropogenic pressures. Key-words: Formicidae,Leptothoraxcaparica, Leptothoraxatlantis, firstrecords, pine stands, SetubalPeninsula, Portugal. r^ Sumario: O Genero Leptothorax Mayr, 1855 (Hymenoptera, Formicidae) na Peninsula Iberica: Primeiros Registos de uma Especie Nova e da Presen^a de L. atlantis Santschi, 1911. No decorrerdeumaprospecfao deFormicidae, efectuadaem pinhais da orla costeira da Peninsula de Setubal, foi descoberta uma especie nova pertencente ao genero Leptothorax Mayr,1855. Foi tambem registada, pela primeira vez na Europa, a presenta de outra especie do mesmo genero, L. atlantis Santschi, 1911. Ambas as especies foram encontradas em solos arenosos e em locais sujeitos a pressoesantropogenicas moderadas. Palavras chave: Formicidae, Leptothorax caparica, Leptothorax atlantis, pinhal, Peninsula de Setubal, Portugal. Unite de Gestion el Economie foresUeres, Faculte universitaire des Sciences agronomiques de GembloiLXBE-5030-Belgique. E-mail:[email protected] ^GUECKO/DCEA,FCT,UniversidadeNovadeLisboa,PT-2825-516CampusdeCaparica,Portugal.E- mail;mrp(S)mail.fct.unl.pt 'Liverpool City Museum.UK-L3SEN-UnitedKingdom. /UVAIffH 6: BolmSoc.Port.Ent.n° 196(VII.14): 161-166,2001 Introduction Portugal is a geographical region with a high percentage of endemisms comparatively to its size, considering higher plants and vertebrates (eg WIERINGA,' ^fr^' /^^^™''^ ^'^""^ can be expected to occur regarding the invertebrate fauna although the overwhelming majority of taxa have been insufficiently studied Such IS the case ofthe Formicidae, for which only a few references were published in the 20th century. In 1932, SANTSCHI listed 32 species; in the following decades localised samplingwas done by SCHMITZ (1955), COLLINGWOOD and YARROW (1969) and COLLINGWOOD (1976). More extensive yet incomplete surveys were conducted in forest ecosystems, namely pines, oaks and eucalyptus stands and in arable habitats by PAIVAe/a/. (1990), CAMMELL e? a/. (1996) and WAY et al. C(1O99L7)L.INIGdeWntOifOiDcat(i1o9n76)kaenydsCOLfLorINthGeWOIbOeDriaanndaPntRIfNaCuEna(19w9e8r)e. produced bv In the course ofstudies aiming at establishing trophic relationships between ants and phytophagous insects in pine ecosystems, a limited survey was conducted in stands borderingthewestern coastofthePeninsula of Setiibal, at the edgeofCaparica coast. Results will be published elsewhere, while here we report exclusively on two important findings from a taxonomicperspective. Materials and Methods A survey ofthe ant fauna was conducted in a pine stand located in Herdade da Aposti9a, latitude: 38° 32' N; longitude: 09° 09' W; ahitude: 35 m a.s.l. The stand ongmated by natural regeneration after fire, the main tree species represented being Pinuspinaster, with some P. pinea intermingled. The shrub layer was dominated by Thymus vulgaris L., Cystus salvifolius L. and Lavandula stoechas L.. In the herbaceous layer the dominant species were Therocistus guttatum (L.) and Carpobrotus edulis (L,). The soil is sandy and relatively shallow, which partially accounts for the small size and poorcondition of thetrees. Ant sampling was done by setting up sugar baits along transepts, as described by CAMMELL etal. (1996) and PAIVA et al. (1998). The baits were controlled 30 minutes and one hour after being set in place, and the ants collected for later identification inthe laboratory. Several surveys were conducted between March and September2000. Results In the Spring of 2000, two original Leptothorax species were discovered The first species was collected on April 6* and identified as Leptothorax atlantis Santschi,1911, although the profile of the petioles' frontal part ofsome ofthe workers IS slightly curved, which does not exactly correspond to the drawings ofCAGNIANT and ESPADALER (1997). Later in the season, in June and September, several nests of this species were observed at the same site, on the fossil dunes of Arrabida, surroundingthelagoonofAlbufeira, ina50years old stand oi P. pinaster. So far] this small Myrmicinae had been recorded only in North-Africa The specimens of Z,.' atlantiscollected are kept in the personal collection of C. COLLINGWOOD. A second original species belonging to the L. rottenbergii (Emery, 1870) group, was caught on June 20* According to the description of SANTSCHI . Heninetal.-TheiberianLeptothorax: discoveryofanewspecies 163 (1909), it is very similar to the Canarian L. risii Forel, 1892. However, several characteristics of pilosity, petiole and thorax profile, size and epinotal spines distinguish the four specimens that we collected and have thus named Leptothorax caparica sp. n,. Some workers were picked up from a nest, located about 4 kms away from the fossil dunes, in a path bordering a house, on bare ground. According to BOLTON (1987, in COLLINGWOOD and KUGLER, 1994), the followingparameters and indiceshavebeen measuredto characterisethe species; total length (TL), head length (HL), head width (HW), cephalic index [CI = (HW*100) / HL], scapelength(SL) and scape index [SI= (SL*100)/HW] - Table 1. Ant ^^ BolmSoc.Port.Ent.n° 196(VII-14): 161-166,2001 The holotype and paratype 1 are kept in the collections ofthe Department of Zoology, Faculte universitaire des Sciences agronomiques de Gembloux (Belgium); the second paratype is kept in the City Museum ofLiverpool (England); the third paratype is kept in the collection of GUECKO/DCEA, FCT, Universidade Nova de Lisboa (Portugal). Discussion We have considered L. caparica as belonging to the L rottenbergi group, taking into accountthe following characteristics: - General morphological aspect similar to the other species ofthe group; 2 - Presence ofa rounded pipe-shaped petiole, which is an important characteristic ofthis group (CAGNIANT and ESPADALER, 1997); 3 - Reduced pilosity; 4 - Ecological characteristic: ground-nesting, which in ' the L(eBpEtRotNhAoRraDx, genus is an archaic characteristic typical of the rottenbers6ii &erouvo 1968), Leptothorax is a monomorphic genus, showing reduced variation in size among the workers. The workersthat we collected have an average length of2.3 mm (varying mm between 2.2 and 2.6 mm), thus being cleary smaller than those ofthe other species oftheL. rottenbergigroup which, according to CAGNIANT and ESPADALER (1997) measurebetween3.0 and 4.0 mm. Two species might be considered as closely related to the workers ofZ. caparica, L risii Forel and L. anacanthus Santschi. However, both species can be cleary distinguished sinceL. risii workers measure between 3.0 and 3.7 mm, havean "importantwhitish pilosity" (SANTSHI, 1909) and lackthe interruption of the thorax profile at meso-epinotum level, seen in the profile ofL. caparica, which shows a broken line - Figure 2. Furthermore the epinotal spines point upwards, while those ofZ,. caparica point backwards. So far L. risii was found on the Canary Islands only (CAGNIANT and ESPADALER , 1997). Regarding L. anacanthus, this species has largerworkers, measuringup to 4.6 mm, aprofil ofthe petiole different fromthat of L. caparicaand spines even shorterthaninZ. risii (SANTSHI, 1909). 28 species of the genusLeptothorax are distributed in the Iberian Peninsula (COLLINGWOOD, 1976), fi-om which 11 only have been recorded from Continental Portugal (COLLINGWOOD and PRINCE, 1998). Our survey detected the presence of L. atlantis for the first time in Europe, which belongs to the group angustulus containing mainly tree dwelling species. This species generally lives in oak stands, although it can also be found in sparse cedar stands (CAGNIANT and ESPADALER, 1997). However, L. atlantis is not dependent on aphids or other Homoptera, that are generally relatively specialised in the plant(s) they colonise. This independence fi-om honeydew producers may potentially allow the ants to have less specific requirements regarding suitable habitat characteristics, which probably explains its presence in apine stand. The species new to science that we found was named L. caparica in accordance to the general area where it was collected, and furthermore as a token to the Faculty of Sciences and Technology, located on the Campus ofCaparica. The two findings reported bring to 13 the number of Leptothorax species recorded in Continental Portugal. But most probably the ant fauna of this country includes many Heninetal.-TheiberianLeptothorax: discoveryofanewspecies 165 Other species which still remain to be found. We would like to conclude with ESPADALER and LOPEZ-SORIA (1991) by suggesting "the rarity in Mediterranean ant species may be explained by the insufficient sampling ofadequate microhabitats, orby the inconspicuousness of social parasitic species. So, previous published species lists of ants fromMediterranean habitatsmight beratherincomplete". Acknowledgements We thank Mrs. Evelyne MOURA and M.Sc. Ana Paula MARTINHO for support with the field work. We are most grateful to Instituto para a Cooperagao Cientifica e Tecnologica, Lisbon, Portugal, for a scholarship awarded to the first author. This research project was sponsored by PRAXIS XXI, contract nr. 2/2.1/BIA/221/94, andby Centro de Ciencia DCEA/FCT/UNL, Portugal. References Bernard, F. 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