Leptanilla plutonia

Leptanilla plutonia has been known from a single worker for more than 20 years. This original material was collected from a soil sample taken from a small slope of a seasonal water course. Recently Perez-Gonzalez et al. (2002) collected 63 specimens from slopes of a low hill system near Tortuero, Guadalajara province, Spain. The specimens came from a soil sample (a 30kg sac, included superficial and deep soil layers (horizons A and B) up to 30–50 cm deep) taken near the slope of the streambed, near hawthorn and rockrose bushes. The soil was reddish, rich in clay, fresh and moist, with plenty of flat slate fragments of different sizes. The main vegetation in the area was composed by patches of oak forest (Quercus faginea Lam.), with scattered hawthorns (Crataegus monogyna Jacq.), wild roses (Rosa canina L.), rockroses (Cistus sp. L.) and lower herbaceous vegetation. The lower part of the slope included the dry bed of an intermittent stream, where long grasses and rushes (Juncus sp. L) were also abundant.

Identification
Large sized Leptanilla, up to 1.91 mm long, yellowish–caramel color, recognizable by the following combination of features (Perez-Gonzalez et al., 2020.):
 * head with smoothly convex lateral sides and occiput almost straight on average
 * covered in a single type of long pilosity
 * labrum bilobate with secondary labrum associated
 * profile of propodeum convex, petiole clearly longer than wide, postpetiole as long as wide
 * petiole and promesosternal region each with a well-developed ventral keel or process
 * sting visible in dorsal view

Distribution based on Regional Taxon Lists
Palaearctic Region: Iberian Peninsula, Spain.

Nomenclature

 *  plutonia. Leptanilla plutonia López, Martínez & Barandica, 1994: 194, figs. 8, 11 (w.) SPAIN.

Worker
CL = 0.32; CW = 0.25; SL = 0.14; PL = 0.14; PW = 0.11; PPL = 0.12; PPW = 0.12; TL = 1.74; CI = 76.92; SI = 181.82; PI= 81.82; PPI = 100.00; PPPI = 90.00 (N = 1).

Colour yellow orange-coloured. Legs paler. Margins of head, alitrunk, petiole, postpetiole, and first gastral segment brownish in dorsal and lateral view. Integument striated (much more clearly than in Leptanilla zaballosi and Leptanilla charonea) in the anterior margins of pronotum and mesonotum, and ventrally in the alitrunk and petiolar node. Pilosity longer and less scattered than in L. zaballosi and L. charonea, subdecumbent to decumbent in the antennae and tarsa, and erect to suberect in the rest of the body; more scarce in the alitrunk.

Head flattened above, wider than alitrunk, less elongated and with less parallel sides than in L. zaballosi and L. charonea. Occiput straight. Tentorium with general morphology as in L. zaballosi, but bigger and with more elongated internal plates. Two small dark red spots inside the head in the right anterior margin. Clypeus straight, neither notched, nor protuding. Mandibles long and narrow, with 4 teeth: a long apical tooth, 2 large grouped sharp-pointed basal teeth and a small median tooth placed in the margin of the mandibles besides the basal teeth. Internal side of mandibles with 3 long setae. Antennae with 12 segments, more stout and with scapes more slender than in L. zaballosi and L. charonea. The latter reach the middle of the head, and they are as long as the 4 proximal funicular segments together. First and second funicular segments pedunculate. The first one not as long as the 2nd and the 3rd together. Funicular segments 3-10 quadrate, forming 2 groups of different size: 3-6 (smaller) and 7-10 (bigger). Last funicular segment elongated, clearly longer than the two preceding segments together, with a sharp-pointed tip.

Alitrunk elongated, but clearly shorter and narrower than the gaster. Prothorax subovoidal, almost as wide as long in dorsal view, separated with a deep promesonotal furrow from the rest of the alitrunk. Prosternum strongly protruded. In lateral view, pronotum more convex than in L. zaballosi and L. charonea. Mesepinotum also subovoidal, but clearly longer than wide; its dorsal margin is straight in lateral view, without depression between the mesonotum and the propodeum. Katepisternum protruded. Hind dorsal margin of propodeum rounded (more softly than in L. zaballosi and L. charonea) far behind the propodeal spiracle. Legs stout, but fore tibiae and all femora are not swollen as in L. zaballosi and L. charonea. Basitarsus of fore legs without projection on its ventral anterior margin. Tibial spurs as in L. zaballosi.

In dorsal view, petiole node elongated, clearly longer than wide, with its anterior margin emarginated. Postpetiolar node subquadrangular, as long as wide, not as clearly wider posteriorly as in L. zaballosi and L. charonea. Its anterior margin feebly emarginate. In lateral view, both nodes dorsally and ventrally convex. Petiolar spiracles clearly visible. Dorsal anterior margin of the petiolar node rounded, slighty directed downwards, ventrally with a plate-like keel feebly serrated, followed by three minute teeth. Postpetiolar node clearly emarginated in its anterior margin, without any projection in its ventral margin.

Gaster ovoidal, less slender than in L. zaballosi and L. charonea; anterior margin feebly emarginated. First gaster tergite longer than the others. Sting comparatively shorter than in L. zaballosi and L. charonea protuding, with the bulb clearly wider than the shaft.

Type Material
Worker from Navas de Estena, Ciudad Real, Spain, UTM 3osUJ77, altitude 690m, 10-V-1988, V. Ortufl.o leg. Preserved in the catedra de Entomologia collection, Facultad de Biologia, Universidad Complutense de Madrid.

Etymology
The specific name plutonia is derived from the latin term pluto, plutonis, by-name of Hades, god of the subterranean world in Greek and Latin cultures.

References based on Global Ant Biodiversity Informatics

 * Borowiec L. 2014. Catalogue of ants of Europe, the Mediterranean Basin and adjacent regions (Hymenoptera: Formicidae). Genus (Wroclaw) 25(1-2): 1-340.
 * Sanchez-Gil Jimeno R., and J. L. Reyes-Lopez. 2016. Study of ants species of the Sierra de San Carlos del Valle (Ciudad Real) and updating the provincial check list (Hymenoptera, Formicidae). Boln. Asoc. esp. Ent. 40 (1-2): 93-109.
 * Scupola A., and R. Ballarin. 2009. The genus Leptanilla Emery, 1870 in Sicily (Hymenoptera: Formicidae). Myrmecologische Nachrichten 12: 129-132.