Pheidole balcanica

Pheidole balcanica
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Pheidole
Species:	P. balcanica
Binomial name
	Pheidole balcanica; Seifert, 2016

This species has been separated from Pheidole pallidula according to a discriminant analysis of a suite of morphological measurements. Nothing is known about its biology.

Mediterranean populations of the taxon named Pheidole pallidula have recently been divided into four species, three of them recorded in Greece (Seifert, 2016), but this revision is still under discussion owing to the great local variability of this very common Mediterranean ant. From the northern Aegean Islands was recorded Pheidole balcanica and Pheidole koshewnikovi (Borowiec et al., 2022).

Identification

Seifert (2016) - The Eurasian species Pheidole pallidula, Pheidole balcanica and Pheidole koshewnikovi are hardly separable by simple eye inspection. There is a number of RAV-corrected shape variables with highly significant differences but also a very large overlap (Tab. 2). Ph. pallidula differs from the two eastern species by shorter scape, shorter hind femur, higher petiole and broader mesosoma. Ph. balcanica differs from koshewnikovi by smaller eye length and smaller minimum distance between the margin of antennal sockets. The larger postocular and preocular distances of Ph. balcanica are a consequence of the smaller eye length. With all characters expressed as absolute measurements in millimeter, Ph. pallidula can be separated from the two eastern species by the discriminant:

DPBK = 13.921+19.038*PoOc-4.581*ExOcc -39.321*CL+4.478*CW+16.902*dAN-17.701*SL +21.869*MW+14.712*PEW-13.948*PPW-0.689*PnHaa +69.968*PEH+46.064*PrOc +24.301*EL+9.049*GuHL-10.011*ML-14.540*Fe3L.

Positive DPBK values indicate Ph. pallidula, negative ones the two eastern species.The classification error is 1.4% in 280 individuals. The two eastern species Ph. balcanica and koshewnikovi can be separated by the discriminant:

DBK = 4.071+29.323*PoOc+4.580*ExOcc -23.743*CL+5.688*CW-9.598*dAN+12.788*SL-16.049*MW-24.383*PEW+11.550*PPW +13.556*PnHaa+2.336*PEH+52.893*PrOc-81.249*EL+12.055*GuHL+7.378*ML-9.450*Fe3L.

Positive DBK values indicate Ph. balcanica, negative ones Ph. koshewnikovi. The classification error is 3.1% in 191 individuals. Attempts to find a simpler species identification by use of a smaller number of characters unfortunately did not result in acceptable classification errors. Users may run their own analyses using the primary measurement data of all 280 individuals provided as an Excell file in the electronic supplement (www.soilorganisms.org).

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 45° to 37°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Palaearctic Region: Bosnia and Herzegovina, Bulgaria, Croatia (type locality), Greece, Montenegro, Türkiye.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Castes

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

balcanica. Pheidole balcanica Seifert, 2016b: 15, figs. 5-7 (s.w.) CROATIA.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Major caste – All data of shape variables given in the following description refer to specimens with a cephalic size CS of 1.25 mm.

Medium-sized, on the average larger than Ph. pallidula: CS 1.106–1.457 mm. Head rather short: ratio of maximum median cephalic length against maximum cephalic width 0.90–0.97. Outlines of head in dorsal aspect without linear components: pre- and postocular head sides and occipital corners convex, the hind margin is strongly concavely excavated, depth of excavation 7–12 % of maximum median head length. The eye is the smallest within the Ph. pallidula species complex: ratio of maximum eye diameter against cephalic size 0.118–0.148. Frontal carinae diverging caudad. Anterior half of dorsal head surface longitudinally carinulate caudad to about one eye length posterior of caudal eye margin. The space between carinulae rather smooth and shining, without conspicuous microsculpture. Posterior half of dorsal head surface smooth and shining. Frontal triangle smooth and shining. Clypeus with exception of a median carinula and several paramedian or lateral ones smooth and shining. Masticatory border of mandibles toothless with the exception of a very strong apical, strong subapical and a weak subbasal dent. Anterior margin of hypostoma with two dents or blunt protrusions. Scape and hind femur short: ratio of scape length against cephalic size 0.55–0.61 and ratio of hind femur length against cephalic size 0.71–0.79. Whole surface of head, scapes, femora, tibiae, promesonotum, waist and gaster with numerous, thin suberect setae. Mesosoma in lateral view with short but sharp and steeply erected propodeal spines, a linear dorsum of propodeum and a well developed metanotal groove. The overall profile of promesonotum is strongly convex and surmounts dorsal propodeum considerably relative to the level of longitudinal mesosomal axis. Outline of promesonotum in dorsolateral (oblique) view without very prominent lobes or protrusions but very flat, obtusely-angled corners – one on dorsolateral pronotum and one or two on dorsolateral mesonotum – are usually visible. Pronotum at small magnifications smooth and shining. Petiole in lateral aspect distinctly longer than high, with a rather straight anterior profile and a small semicircular dorsal crest that appears in dorsal view much wider than long. Whole surface of head, scape, femora, tibiae, promesonotum, waist and gaster with numerous, thin suberect setae.

Type Material

Holotype, a major worker, labelled ‘Holotype Pheidole balcanica Seifert, des. B. Seifert 2015’, ‘CRO: 45.08710°N, 14.84735°E, Smokvica Krmpotska-400 m W, 8 m, Wegrand, unter Stein, Juniperus, Gras, niedriger Wald, Seifert 2014.07.29–85’. Paratypes: 2 mounted major workers, 3 mounted minor workers, 7 ethanol stored majors and 16 ethanol-stored minors from the holotype nest with the same locality label; all material in Senckenberg Museum. für Naturkunde Görlitz.

Etymology

The name is given because large parts of the distributional range are in the Balkans.

References

References based on Global Ant Biodiversity Informatics

Salata S., and L. Borowiec. 2018. Taxonomic and faunistic notes on Greek ants (Hymenoptera: Formicidae). Annals of the Upper Silesian Museum in Bytom Entomology 27: 1-51.
Salata S., and L. Borowiec. 2019. Preliminary division of not socially parasitic Greek Temnothorax Mayr, 1861 (Hymenoptera, Formicidae) with a description of three new species. ZooKeys 877: 81-131.
Seifert B. 2016. Inconvenient hyperdiversity – the traditional concept of “Pheidole pallidula” includes four cryptic species (Hymenoptera: Formicidae). Soil Organisms 88(1): 1-17.