Myrmica siciliana

A high altitude Sicilian endemic that nests in open habitats.

Identification
M. siciliana belongs to the schencki species group. Although it shares many morphological features with other species of the group, it well differs from all others as follows. The female castes well differ from the other species of the schencki-group (except for the oriental Myrmica onoyamai) by their less-extended frontal lobes (mean FLI 1.29 vs. > 1.40); the frontal lobes of M. onoyamai (mean FLI 1.20) are even less extended. The distinctly wide frons of the workers and queens of M. siciliana (mean FI 0.30) well separates them from Myrmica ravasinii, Myrmica schencki and Myrmica pelops. Finally and not least, although subjective and difficult to quantify, the shape of the lobe at the base of scape of workers and queens of M. siciliana appears very different to that of the other species. Males of M. siciliana most resemble those of M. schencki but differ from them by a relatively longer and lower petiole, and by a distinctly less angled curve at the base of the scape. They are easily distinguished from those of M. ravasinii and Myrmica caucasicola by the short standing hairs on legs and antennae; from Myrmica deplanata by a distinctly longer scape, and from M. onoyamai and Myrmica koreana by a somewhat longer scape that is distinctly curved at its base.

Key to Myrmica of West Europe and North Africa

Distribution
Sicily.

Distribution based on Regional Taxon Lists
Palaearctic Region: Italy.

Biology
Radchenko and Elmes (2010) - M. siciliana lives in the mountains of northeast Sicily at fairly high altitudes ( > 1500 m). Generally they nest in the soil in areas of grazed grassland with no obvious above-ground nest structure; we did not see woven funnel entrances that are typically associated with Myrmica schencki, Myrmica koreana, Myrmica obscura and several North American schencki-like species. M. siciliana sometimes nests in open grassy areas: glades or even bare areas in beech-woods, but they are most abundant in damp areas of open grazed grassland. They do not require permanently wet soil, rather they live on the drier margins of ponds and areas temporarily flooded following heavy rain. M. siciliana colonies face quite strong competition from Myrmica sabuleti and Tetramorium, Lasius, Formica and Aphaenogaster species and like many other species of Myrmica in such circumstances, they forage mostly in the early morning and early evening. This species was believed to be restricted to the Mt. Nebrodi region of Sicily but we found two specimens (queen and worker foraging in mature woodland) on the neighbouring Mt. Etna region. It is probably endemic to just these Sicilian mountains but we cannot rule out the possibility that it might also live in the adjacent Calabrian mountains of southern Italy.

When collecting we observed the end of a nuptial flight in an area of damp grassland (ca. 0.5 ha) among open mixed woodland where the holotype nest had been taken on August 28th 2005. Sexuals of both Myrmica siciliana and Myrmica spinosior were found leaving their nests and we caught both alate and dealate queens on the ground. The actual swarm was not located but we guess it was centred on one of the trees in the small meadow, and was a fairly local affair because swarming on the day did not seem to be widespread.

Nomenclature

 *  siciliana. M yrmica siciliana Radchenko, Elmes & Alicata, 2006: 502, figs. 2-21 (w.q.m.) ITALY (Sicily). See also: Radchenko & Elmes, 2010: 277.

Worker
Head longer than broad, with slightly convex sides, straight occipital margin, and quite broadly rounded occipital corners. Anterior clypeal margin broadly rounded and distinctly notched medially. Frontal carinae not strongly curved, frons relatively wide and frontal lobes not proportionately extended (compared to M. schencki). Scape strongly angled at the base, with only a moderately developed, somewhat oblique vertical lobe, forming a small shield the on vertical face of antennal foot.

Alitrunk with convex promesonotal dorsum; promesonotal suture indistinct from above; metanotal groove distinct, but not deep. Propodeal spines long, acute, almost straight, divergent (seen from above), projecting backwards at an angle less than 45°. In profile, anterior surface of petiole concave, meets with dorsal surface at a blunt angle, dorsal surface gradually sloping posteriorly, at most slightly flattened. Postpetiole distinctly shorter than high, with convex dorsum. Spurs on middle and hind tibiae well developed and pectinate.

Only frons with sinuous longitudinal rugae, remainder part of head dorsum with reticulation. Antennal sockets surrounded by concentric rugae. Clypeus with longitudinal rugae, frontal triangular striated. Sides of alitrunk with moderately coarse sinuous rugae, pronotum 'with reticulation. Sides of petiolar node with longitudinal rugosity, its dorsum with reticulation. Postpetiole •with longitudinally-concentric rugae. Surfaces between rugae on the body smooth and shiny.

Hairs on the head margins and alitrunk dorsum abundant, erect to suberect, quite long and slightly curved; scape with suberect, and tibiae with subdecumbent hairs. The overall colour reddish-brown, appendages somewhat lighter.

Queen
Generally like workers in shape of head and scape, colour and pilosity of the body except they have coarser sculpture, especially on the alitrunk, petiole and postpetiole. Frons relatively slightly wider and propodeal spines shorter and wider at their base.

Male
Head slightly longer than broad, with convex sides and occipital margin, and gradually rounded occipital corners; anterior clypeal margin widely rounded and longer than first and second funicular segments together, distinctly curved at the base though not sharply angled. Antennae 13-segmented, with 5-segmented club.

Alitrunk relatively long, scutum slightly convex, scutellum does not project dorsally above scutum when seen in profile. Propodeum with blunt rounded tubercles. In profile, petiole relatively long and low, with widely rounded dorsum of node, its anterior surface slightly concave, not steep; postpetiole distinctly higher than long, with weakly convex dorsum.

Head dorsum finely but densely punctured, frons with fine striation, temples with coarser rugulae. Central part of scutum behind Mayr's furrows, and scutellum with fine longitudinal striation. Propleura with fine striation and rugulosity, mesopleura and propodeum coarsely rugulose. Sides of petiole finely punctured, petiolar dorsum and postpetiole smooth and shiny. Surface of alitrunk between striation and rugae smooth and shiny.

Head margins with long, curved erect hairs. Alitrunk, petiole and gaster with somewhat shorter erect to suberect hairs, postpetiole with longer hairs. Tibiae and tarsi with short subdecumbent to suberect hairs; scape and first 7 funicular segments with relatively long hairs, segments of antennal club with very short subdecumbent hairs. Colour of body dark brown to black, appendages somewhat lighter.

Type Material
Holotype worker, Italy, Sicily, Monti Nebrodi, Piano Menta, 1500 m a.s.l., grassland in a damp area, 2.X.2004, leg. A. Alicata (AA 3/04), Museo Civico di Storia Naturale, Milano, Italy ; paratypes: 5 workers, 9 males from the nest of the holotype, (Isc 20- Elmes coll.); 1 queen, Italy, Sicily, Monti Nebrodi, Piano Menta, 1500 m a.s.l., grassland in a damp area, 2.X.2004, leg. A Alicata (AA 2/04, Isc 18 in Elmes coll.); 17 workers, 40 males, the same locality, date and collector as previous (AA 3/04, Elmes Isc 21); 5 workers, 1 male, Italy, Sicily, Monti Nebrodi, Portella Scafi, ,1450 m a.s.l., grassland near pond, 2.X.2004, leg. A. Alicata (AA 6/04, Elmes Isc 23); 8 workers, 6 males, Italy, Sicily, Monti Nebrodi, near Pizzo Scavello, 1575 m a.s.l., bare patch in a beech wood, 1.X2004, leg. A. Alicata (AA 5/04, Elmes Isc 22); 28 workers, 2 queens, 5 males, same locality and collector as previous, but date 2.X.2004 (AA 1/04, Elmes Isc 19); 4 workers, 1 queen, 2 males, Italy, Sicily, Monti Nebrodi, Serra del Re (pond), 1710 m a.s.l., bare patch in a beech-wood, 19.IX.2002, leg. A Alicata (AA 4/03, Elmes Isc 17); 15 worker, 5 males, Sicily, reg. Monti Nebrodi, Mt. Soro, Piano Menta ca. 1550 m. N facing escarp. grazed open place among trees. nest in soil. 28-VIII-2005. leg. Elmes (lsc24); 33 workers, 9 males (Isc25), (same collection details); 48 workers, (Isc26), (same collection details); 24 workers, (Isc2:7), (same collection details); 3 queens, (Isc15), mating swarm just ending, taken from random sample of 3 Myrmica spp. and Lasius 'and Aphaenogaster running on the ground, (same site details); 30 workers, 4 males, NE Sicily, reg. Monti Nebrodi, Mt. Soro, Piano Menta, ca. 1450 m. N facing escarp. grazed damp “lawn”, nest in soil at edge of damp place, 28-VIII-2005. leg. Elmes (Isc28) (,, , , ALICATA).

Etymology
This species is named after Sicily, where it was collected.