Tapinoma erraticum bononiensis Emery, 1925

Seifert, Bernhard, Kaufmann, Bernard & Fraysse, Lorenzo, 2024, A taxonomic revision of the Palaearctic species of the ant genus Tapinoma Mayr 1861 (Hymenoptera: Formicidae), Zootaxa 5435 (1), pp. 1-74 : 34-35

Tapinoma erraticum bononiensis Emery, 1925 [type investigation]

The species has been described from the vicinity of Bologna / Italy. Investigated were the lectotype worker and 2 paralectotype workers labelled “Bologna” [Emery’s handwriting], “ Lectotype Tapinoma erraticum bononiensis Emery, 1925 bottom specimen des. B.Seifert 2013”; depository MCSN Genova. The lectotype series is allocated to the T. erraticum cluster with p= 0.9292 in a wild-card run of a LDA considering 12 morphometric characters ( Tab. 1) .

Material examined. Numeric phenotypical data were taken in 49 worker samples (largely nest samples) with 131 workers. They originated from Bosnia (1 sample), Bulgaria (1), Czechia (2), France (5), Great Britain (1), Germany (19), Greece (1), Italy (14), Macedonia (1), Serbia (1), Slovenia (1), Spain (1) and Switzerland (1). For details see supplementary information SI1, SI2 .

Geographic range. European , south temperate and submeridional. According to examined vouchers the range includes S England, N Spain, France, Central Europe north to 52°N , Italy and the West Balkans. The eastern and southern limits of the range are marked by 24° E and 39°N .

Ascending to 950 m in Baden-Württemberg, to 1300 m on highly montane pastures of Vorarlberg and to 1800 m in the Pyrenees (42.7°N) .

Diagnosis:—Worker ( Tab. 2, Figs. 35–37 ): All shape ratios given below are, in contrast to those in Tab. 2, primary ratios without RAV and all data are given as arithmetic mean ± standard deviation. Medium sized to small, CS 763 ± 88 µm. Head moderately elongated CL/CW 1.123 ± 0.043. Postocular distance medium-sized, PoOc/CL 0.409 ± 0.009. Anteromedian clypeal excision usually deeper than wide, ExCly/CS 8.42 ± 0.87 %, ExClyW 6.58 ± 0.65 %. The margin of clypeal excision forms a sharp cuticular edge beginning from its frontal corners caudad over at least 70% of its length and is in this area at same level as the adjacent clypeal surface. Sum of pubescence hairs and smaller setae protruding at a few microns across margin of clypeal excision low, nExCly 2.57 ± 1.53. Posterior margin of head in full face view in medium-sized and large specimens slightly excavated, ExOcc/CS 1.35 ± 0.63 %. Scape moderately elongated, SL/CS 1.017 ± 0.022. Minimum distance of the inner margins of antennal socket rings medium-sized, dAN/CS 0.289 ± 0.008. Eye medium-sized, EL/CS 0.260 ± 0.007. Metanotal groove rather deep, MGr/CS 3.87 ± 0.91 %. Mesosoma relatively wide and long, MW/CS 0.665 ± 0.025, ML/CS 1.355 ± 0.029. Second funiculus segment moderately long and slender, Fu2L/CS 14.29 ± 0.40 %, IFu2 1.634 ± 0.071. Head, mesosoma and gaster covered by a rather dense pubescence. Anterior margin of clypeus with a few standing setae, the two longest and strongest are based near to the anterolateral margin of clypeal excision. Remaining surface of head capsule and dorsal mesosoma without standing setae, such are present on mandibles, coxae and ventral surface of gaster. Head, mesosoma and gaster dark blackish brown. Antennae, femora and tibia dark brown. Tarsae and metatarsae usually pale yellowish brown.

—Male genital (Fig. 08): Ventral aspect. Lobes of subgenital plate rather broad, their length extends over 60 to 80% of the visible length of the basimere. Apical margins of the lobes straight to weakly convex. The mediodistal part of the basimere forms a sharp spine-like extension directed caudad. Harpago segments rather small, their lateral margins are only weakly incurved towards the tip.

Taxonomic comments. Based on worker morphology, the next relatives of Tapinoma erraticum are T. israelis and T. glabrella . The 128 nest samples of these three species can be fully separated by a principal component analysis using the RAV-corrected characters CL/CW 900, SL/CS 900, ExCly/CS 900, ExClyW/CS 900, ExClyL/W 900, nExCly 900, dAN/CS 900, EL/CS 900, MGr/CS 900, MW/CS 900, ML/CS 900, and Fu2L/CS 900 ( Fig. 41 ). Using the same characters, 96.3% of 380 worker individuals are correctly classified by linear discriminant analysis (LDA) and the nest sample means form widely separate clusters. The classification of the type series of the species related to T. erraticum according to wild-card runs of the LDA is given in Tab. 1. A relatedness of T. erraticum and T. glabrella is indicated by the similarity of the basic structure of male genitalia. The male of T. israelis is unknown.

Biology: For a condensed description of biology see Seifert (2018) but see also Wagner (2019) and De Pletincx & Aron (2022).

Figures

FIGURE 35. Tapinoma erraticum, neotype, head in full face view, Nespouls-Faugère / France, 2008.07.02.

FIGURE 36. Tapinoma erraticum, neotype, lateral view, Nespouls-Faugère / France, 2008.07.02.

FIGURE 37. Tapinoma erraticum, neotype, anterior head in dorsofronal view, Nespouls-Faugère / France, 2008.07.02.

FIGURE 41. Nest sample means of the first two principal components extracted from 12 RAV-corrected phenotypical characters. Black squares—Tapinoma glabrella (n=70); white dots—T. erraticum (n=49); black crosses T. israelis (n=9).