ANNALES ZOOLOGICI (Warszawa), 2018, 68(4): 809-824 DESCRIPTION OF PLAGIOLEPIS PERPERAMUS, A NEW SPECIES FROM EAST-MEDITERRANEAN AND REDESCRIPTION OF PLAGIOLEPIS PALLESCENS FOREL, 1889 (HYMENOPTERA: FORMICIDAE) SEBASTIAN SALATA1*, LECH BOROWIEC2, and ALEXANDER G. RADCHENKO3 1Institute for Agricultural and Forest Environment, Polish Academy of Sciences, Bukowska 19, 60-809 Poznań, Poland; e-mail: [email protected] 2Department of Biodiversity and Evolutionary Taxonomy, University of Wrocław, Przybyszewskiego 65, 51-148 Wrocław, Poland; e-mail: [email protected] 3Schmalhausen Institute of Zoology National Academy of Sciences of Ukraine, Kiev, Ukraine; email: [email protected] *Corresponding author Abstract.— A taxon considered in past years as P. pallescens sensu Radchenko is described as a new species: Plagiolepis perperamus sp. nov. based on material from Eastern Mediterranean. Its morphological separation from P. schmitzii Forel, 1895, the second species characterized by dense gaster setosity, is supported by study on their environmental niches. Plagiolepis pallescens Forel, 1889 is redescribed based on type specimens and material collected from various localities spread within Balkans. Its taxonomical status is clarified and a definition of a ‘pallescens group’ is improved and supplemented. Plagiolepis maura var. taurica Santschi, 1920 and Plagiolepis maura var. ancyrensis Santschi, 1920 are synonymized with Plagiolepis pallescens Forel, 1889. Ë Key words.— Formicidae, Formicinae, Plagiolepidini, Mediterranean Region, Ecological Niche Modelling INTRODUCTION a big obstacle in their determination. The only sources of information regarding their taxonomy can be found Plagiolepis Mayr, 1861 is a moderately numerous in papers dedicated to European part of the former genus comprising 61 species and 19 subspecies spread USSR (Radchenko 1989), Central and Southern Palae- within temperate and tropical regions of Old World arctic regions (Radchenko 1996) and Arabian Penin- (Bolton 2018). There are 9 valid names and numerous sula (Sharaf et al. 2011). The only recently published available names of infraspecific rank of this genus works that concern directly Mediterranean members of (Borowiec 2014) known from Mediterranean Region Plagiolepis are taxonomic notes on single species (sensu Vigna-Taglianti et al. 1999). Its representatives (Wetterer et al. 2007, Boer 2008) or new distribution are minute ants, nesting in soil, trees or rotted records (Schifani 2017). wood. Colonies are most often polygynous. Lack of Material collected from east-Mediterranean region modern revisions of Mediterranean Plagiolepis is and study on type specimens of Plagiolepis known PL ISSN 0003-4541 © Museum and Institute of Zoology PAS doi: 10.3161/00034541ANZ2018.68.4.005 810 S. SALATA, L. BOROWIEC and A. G. RADCHENKO from this area revealed that the P. pallescens group data are in original spelling; a vertical bar (|) sepa- has been incorrectly defined. This mistake was noted rates data on different rows and double vertical bars and discussed for the first time by Bračko et al. (2016). (||) separate labels. Additional information about the To stabilize taxonomic status of east-Mediterranean labels or explanatory notes is given in square brackets. members of the P. pallescens group, we provide de - The images of type and non-type specimens, with as - tailed redescription of P. pallescens and describe signed CASENT number, are available at AntWeb a new species for Plagiolepis pallescens sensu Rad- (https://www.antweb.org). Examined specimens are chenko 1996. housed in the following collections: Also, to clarify status of some taxa morphologically CASC – California Academy of Sciences, San Francis- similar to P. pallescens and to avoid their further con- co, California, USA; fusion and misinterpretation, we propose the following BMNH – Natural History Museum, London; definition of the pallescens group: DBET – Department of Biodiversity and Evolutionary – 3rd funicular segment elongate, equal or only slight- Taxonomy, University of Wrocław, Poland; ly shorter than 4th segment; DSAB – Dipartimento di ScienzeAgrarie, Università di – body colouration from dark brown to yellow, most Bologna, Bologna, Italy; often variable within colony; MHNG – Museum d’Histoire Naturelle, Geneva, Swit - – gaster setosity sparse, distance between setae is zer land; equal to full or half of the length of setae. MNHW –Museum of Natural History, University of Remaining Mediterranean Plagiolepis taxa can be Wrocław, Poland; assigned to two other species groups associated with MSNG – Museo Civico di StoriaNaturale,Genova, Italy; P. schmitzii and P. pygmaea, defined below. NHMB –Naturhistorisches Museum, Basel, Switzer- The schmitzii group: land; – 3rd funicular segment elongate, equal or only slight- NHMC – Natural History Museum of Crete, Heraklion, ly shorter than 4th segment; Greece; – body colouration from dark brown to brown, some- SIZK – Schmalhausen Institute of Zoology National times variable within colony; Academy of Sciences of Ukraine, Kiev, Ukra- – gaster setosity dense, distance between setae short- ine; 1 USMB – Upper Silesian Museum, Bytom, Poland; er than /3 of their length. The pygmaea group: ZMMU –Zoological Museum of Moscow University, – 3rd funicular segment quadrate or transverse, much Mos cow, Russia. shorter than 4th segment; The degree of inclination of setosity follows Höll- – body colouration from dark brown to brown, some- dobler & Wilson (1990): adpressed (0–5°) hairs run par- times variable within colony; allel, or nearly parallel to the body surface; decumbent – gaster setosity sparse, distance between setae is hairs stand 10–15°; subdecumbent hair stands 30°; equal to full or half of the length of setae. suberect hairs stand 35–45°; and erect hairs stand Plagiolepis perperamus sp. nov., together with more than 45° from the body surface. P. schmitzii, are the only known Mediterranean spe - cies with dense adpressed setosity on gaster. The lat- Measurements, Indices and Comparative ter species is known from Macaronesia, Maghreb and Material Iberian Peninsula, the regions distant from distribution range of P. perperamus. To resolve if they represent Measurements distinct species we performed ecological niche model- HL –head length; in full-face view, measured in ling. This tool is well-recognised method used in straight line from mid-point of anterior clypeal species delimitation (Steiner et al. 2010, Gurgel Gon - margin to mid-point of posterior margin; çalves et al. 2011, Hawlitschek et al. 2011, Hidalgo- HW – head width, measured in full-face view directly Galiana et al. 2014, Gama et al. 2017). above the eyes; EL – eye length, measured along the maximum diam- eter of eye; MATERIAL AND METHODS EW – eye width, measured along the maximum diam- eter of eye; Taxonomy HTL – hind tibia length, maximum straight-line length of the hind tibia; Specimens were compared using standard methods SL – scape length, maximum straight-line length of of comparative morphology. Photos were taken using the scape; a Nikon SMZ 1500 stereomicroscope, Nikon D5200 pho- PNW – pronotum width; maximum width of pronotum, to camera and Helicon Focus software. All given label in dorsal view; DESCRIPTION OF PLAGIOLEPIS PERPERAMUS AND REDESCRIPTION OF P. PALLESCENS (HYMENOPTERA: FORMICIDAE) 811 ML – mesosoma length; measured as diagonal length hypothesis, supporting niche conservatism, or below from the anterior end of the neck shield to the the 95% confidence interval of the null hypothesis, sup- posterior margin of propodeum. porting niche divergence (Blair et al. 2013). Indices HI – cephalic index; HW/HL × 100; RESULTS SI – scape index; SL/HL × 100; MI – mesosoma index; HTL/ML × 100; Revision. The study of the type specimen of P. pal- EI1 – eye index 1; EW/EL × 100; lescens and an examination of samples collected from EI2 – eye index 2; EW/HL × 100; its terra typica (Rhodes island) revealed that the real TI – tibiae index; HW/HTL × 100. P. pallescens has gaster with very sparse setosity. In its original description (Forel 1889), P. pallescens is All lengths are in mm. characterised also as a species with bright yellow body colouration. Moreover, in further publications (San - Distribution patterns tschi 1920, 1938), all taxa from this group were distin- The concept of chorotypes follows Vigna Taglianti guished additionally based on shape of head and length et al. (1999). The environmental niches of P. perpera- of the scape. In the collected material we sampled sev- mus and P. schmitzii were generated using a maxi- eral colonies containing specimens with mixed body mum entropy method available in MaxEnt v. 3.4.1 colouration, from yellow to brown. Both, light and dark (Phillips et al. 2006), which estimates the optional coloured specimens showed similar level of sclerotiza- potential distribution from presence-only data (Elith et tion of cuticle. Therefore we do not consider this fea- al. 2006). For the MaxEnt calculations, a set of World- ture as useful in species delimitation. Additionally, we Clim (Hijmans et al. 2005) environmental layers (con- observed that the shape of head is correlated with body tinuous variables, resolution of 2.5 arc-min, approxi- size. The small workers have oval head, while big work- mately 5 km2) was used. Although finer resolutions are ers have more trapezoid head. In specimens with more available (30 arc-sec) for the bioclimatic variables, oval head the scape reach beyond the occipital margin these may not be appropriate given uncertainties asso-