Temnothorax lagrecai ( Baroni Urbani, 1964 )

Schifani, Enrico, Prebus, Matthew M. & Alicata, Antonio, 2022, Integrating morphology with phylogenomics to describe four island endemic species of Temnothorax from Sicily and Malta (Hymenoptera, Formicidae), European Journal of Taxonomy 833 (1), pp. 143-179 : 152-156

Temnothorax lagrecai ( Baroni Urbani, 1964)

Figs 16–33

Diagnostic character combination

Antennal clubs concolorous yellowish, antennae 12-segmented in females and 13 in males, eyes normal, metanotal groove very weak or absent, worker propodeal spines long, male propodeal spines dentiform, petiole upper profile usually with a short horizontal component, subpetiolar process toothlike, sculpturing mostly areolate and weak.

Etymology

Baroni Urbani (1964) dedicated this species to the Italian entomologist Marcello La Greca (1914–2001).

Material examined

We investigated 56 colony samples from 23 localities, consisting in a total of 212 ☿☿, 8 ♀♀, 2 ♂♂ from our collections, one colony under rearing in our possession, holotype queen and paratype workers from the MSNV and NHMW collections, and additional non-type workers from the personal collections of David Misfud and Stephen Schembri and from the MSNM. A detailed list is provided in the Supp. file 1: Table S1.

Redescription

Worker ( Figs 19–27 )

MEASUREMENTS AND INDICES (13 specimens, 6 localities, 6 colonies). CL: 547.15 ± 33.51 (488–592); CW: 447.54 ± 31.37 (401–495); CS: 497.35 ± 31.84 (444–543); PoOC: 231.69 ± 14.9 (212–257); SL: 387.77 ± 24.95 (352–435); ML: 603.15 ± 57.6 (527–709); MW: 295.92 ± 26.65 (260–347); EL: 116.85 ± 16.1 (100–153); EW: 87.92 ± 11.19 (78–112); EYE: 102.38 ± 13.28 (89–132); SPST: 147.6 ± 17.97 (120–175); CL/CW: 1.22 ± 0.03 (1.18–1.29); PoOC/CL: 0.42 ± 0.01 (0.40–0.45); SL/CL: 0.71 ± 0.01 (0.68–0.73); ML/CS: 1.21 ± 0.05 (1.15–1.33); MW/CS: 0.59 ± 0.02 (0.56–0.65); EL/CS: 0.23 ± 0.02 (0.20–0.29); EW/CS: 0.18 ± 0.02 (0.15–0.21); EYE/CS: 0.20 ± 0.01 (0.18–0.25); SPST/CS: 0.30 ± 0.02 (0.27–0.32).

COLORATION. Entirely yellowish with the exception of a variably large and often not clearly demarcated black transverse band on the gaster.

HEAD. Subrectangular with rounded margins near the four angles, clypeus and mandibles rounded. Antennae of 12 segments, antennal clubs of 3 segments, antennal scapes relatively short (SL/CL: 0.71 ± 0.01). Compound eyes relatively small, ovoidal (EYE/CS: 0.20 ± 0.01).

MESOSOMA. May present a slight metanotal depression, its dorsal profile being from almost straight to definitely rounded in lateral view. Propodeal spines are relatively long (SPST/CS: 0.30 ± 0.02), usually proportionally thin in minor worker but sometimes considerably thick in large ones.

METASOMA. The petiole in profile view usually presents a short but visible horizontal section.A subpetiolar process is normally visible, consisting of a small tooth angled down at up to 90°. Postpetiole ordinarily roundish in lateral profile, subrectangular in dorsal view.

SURFACE SCULPTURING. Most of the body is characterized by a very fine areolate-rugose sculpture, the longitudinal component of which tends to be notably more marked on the frontal side of the head only in larger specimens. The gaster and appendages are smooth, as well as the clypeus and a variable area extending around the frons. A central longitudinal stria visible in the lower portion of the clypeus. Very sparse, occasionally suberect but usually erect setae all over the body; dense, fine, and mostly adpressed pilosity on all appendages, especially abundant on the antennal flagelli.

Queen ( Figs 28–30 )

MEASUREMENTS AND INDICES (2 specimens, 2 localities). CL: 649–627; CW: 531–548; CS: 579–598; PoOC: 239–256; SL: 457–469; ML: 932–989; MW: 585–585; EL: 190–195; EW: 157–161; EYE: 173–178; SPST: 216–237; CL/CW: 1.08–1.08; PoOC: 0.37–0.41; SL/CL: 0.72–0.73; ML/CS: 1.65– 1.61; MW/CS: 0.97–1.00; EL/CS: 0.32–0.33; EW/CS: 0.27–0.27; EYE/CS: 0.30–0.30; SPST/CS: 0.37–0.39.

COLORATION. Entirely yellowish with the main exception of parts of the gaster: at least the first tergite characterized by a blackish transverse band. Moreover, the mesoscutellar disk is darkened caudally.

HEAD. Subrectangular, with rounded margins near the four angles, clypeus and mandibles rounded. Antennae of 12 segments, antennal clubs of 3 segments, antennal scapes relatively short (SL/CL: 0.72– 0.73). Compound eyes large and ovoidal (EYE/CS: 0.30); ocelli circular.

MESOSOMA. Propodeal spines relatively long (SPST/CS: 0.37–0.39).

METASOMA. Dorsum of petiole in profile view without a horizontal section. Subpetiolar process usually visible, consisting of a small tooth. Postpetiole ordinarily roundish in profile, subrectangular in dorsal view.

SURFACE SCULPTURING. Most of the body is characterized by a variably fine areolate-rugose sculpture, strong longitudinal rugae on the head. Clypeus. gaster and appendages smooth; a variable area extending around the frons, most of the pronotum, anepisterna, katepisterna, mesoscutellar disk and mesoscutum. A central longitudinal stria visible in the lower portion of the clypeus. Very sparse, occasionally suberect but usually erect setae all over the body; dense, fine, and mostly adpressed pilosity on all appendages, especially abundant on the antennal flagelli.

Male ( Figs 31–33 )

MEASUREMENTS AND INDICES (3 specimens, 2 localities). CL: 443 ± 13.11 (429–445); CW: 405.67 ± 3.51 (402–409); CS: 424.33 ± 7.84 (415–430); PoOC: 189.67 ± 2.51 (187–192); SL: 203 ± 4 (199–207); ML: 836.67 ± 5.13 (832–841); MW: 498.67 ± 3.78 (496–503); EL: 186.67 ± 6.03 (181–193); EW: 165.67 ± 3.78 (163–170); EYE: 176.16 ± 3.62 (172–178); SPST: 126.33 ± 4.51 (122–131); CL/CW: 1.04 ± 0.01 (1.03–0.06); PoOC/CS: 0.43 ± 0.01 (0.42–0.43); SL/CL: 0.45 ± 0.01 (0.45–0.46); ML/CS: 1.97 ± 0.04 (1.93–2.01); MW/CS: 1.17 ± 0.03 (1.15–1.21); EL/CS: 0.44 ± 0.01 (0.42–0.45); EW/CS: 0.39 ± 0.02 (0.38–0.41); EYE/CS: 0.41 ± 0.01 (0.40–.043); SPST/CS: 0.30 ± 0.02 (0.28–0.31).

COLORATION. Whole body yellowish, head slightly darker, appendages whitish, gaster dark and mesoscutellar disk caudally darkened.

HEAD. Subrectangular, rounded especially above the eyes; clypeus and mandibles rounded. Antennae of 13 segments, antennal clubs of 4 segments. Compound eyes large and ovoidal (EYE/CS: 0.41 ± 0.01); ocelli circular.

MESOSOMA. Propodeum armed with very short and thick spines (SPST/CS: 0.30 ± 0.02).

METASOMA. Postpetiole ordinarily roundish in profile, subrectangular in dorsal view.

SURFACE SCULPTURING. Sculpture relatively strong on the head, with well-developed longitudinal striae on its frontal side, very light all over the propodeum, petiole, postpetiole and in some areas near the mesosoma lateral sutures, all the remaining parts smooth. A central longitudinal stria visible in the lower portion of the clypeus. Sparse, erect setae all over the body; fine and mostly adpressed pilosity over the appendages.

Phylogeny ( Fig. 79 )

Sister species of T. marae Alicata, Schifani & Prebus sp. nov., which together are closely related to T. flavicornis .

Distribution and biogeography ( Figs 80–81 )

Occurs almost all over Sicily and is also found in the Maltese Islands. In the past, Sicily and the Maltese Islands have been connected via an extensive land bridge covering a large area of currently shallow waters, and the last time such a connection existed was during the Last Glacial Maximum ( Foglini et al. 2016).

Ecology and conservation

Relatively thermophilous, collected from 5 to 840 m a.s.l. (see Fig. 82 ). Temnothorax lagrecai inhabits Mediterranean shrublands and relatively open forests like native and artificial forests of Pinus halepensis Mill. , sometimes found under trees of Quercus ilex L., but was also collected in artificial gardens in the leaf litter of trees of Citrus L. Due to the wide ecological niche and distribution it may face a relatively positive situation in conservationist terms, but further assessment would be interesting.

Nesting

Nests are found in the soil, probably opportunistically exploiting several kinds of microhabitats when available. On Monte Etna entire nests were found several times under moss.

Biology

Monogynous in all documented cases.

Social parasites

One colony was found to be hosting T. muellerianus (Finzi, 1922) in the R.N.O. Pino d’Aleppo (Vittoria).

Phenology

Flying queens and males (often attracted by artificial lights) and mating were observed in Mondello (Palermo) from the early days of July to late August at least.

Notes

Baroni Urbani (1964) assembled the type series of this species from an unspecified number of worker specimens and a single queen collected in Bosco di S. Pietro (Hyblaean Plateau, SE Sicily) by Giovanni Sichel. No additional information on this taxon was published after its description, and its name was mentioned only on very few occasions ( Baroni Urbani 1971; Salata & Borowiec 2019). Baroni Urbani decided to define the only queen he had as the holotype, despite the specimen being damaged (missing both antennae) and with the taxonomy of Temnothorax being mostly built around workers. He based the worker caste description on a specimen he defined as the ‘ergatotype’, but this definition has no legal value anymore according to the ICZN code, therefore that specimen must be considered as a simple paratype. We examined the holotype along with several paratypes preserved at the Natural History Museums of Verona and Vienna, but our efforts to find the ergatotype failed. Over 20 years ago, it was briefly observed at the home of Bruno Poldi (1920–2002) by one of us (AA), but it appears to be absent from the MNHM where Poldi’s collection is kept, as well as from the MSNV, NHMB and NHMW where other material from Baroni Urbani and specimens of T. lagrecai are stored. According to its description, the ergatotype shows several characters deviating from all type and non-type workers of T. lagrecai that we have found; however, it is unclear whether this is due to the actual features of this lost specimen or an imprecise description. Temnothorax marae sp. nov. cooccurs with T. lagrecai in the Bosco di S. Pietro, yet it is not characterized by the sharp petiole and mesoepinotal furrow of the drawing of the ergatotype of T. lagrecai found in Baroni Urbani's original description. In any case, the holotype of T. lagrecai , although partly damaged, is fully coherent with the morphology of the queens collected alongside workers with the same characters of T. lagrecai that we present here, so that we consider the issue over the identity of T. lagrecai to be resolved.

Maltese records under Leptothorax rabaudi Bondroit, 1918 by Schembri & Collingwood (1981) are partly based on misidentified T. lagrecai according to an investigation of their voucher specimens.

Figures

Figs 16–18. Morphometric characters recorded from workers of Temnothorax Mayr, 1861 in this study. The background image is a paratype worker of T. lagrecai (Baroni Urbani, 1964) from the Natural History Museum of Vienna, photos by Anna Pal available from www.antweb.org, specimen identifier CASENT0919741. 16. Head view. 17. Lateral profile view. 18. Dorsal view of the mesosoma.

Figs 19–33. Specimens of Temnothorax lagrecai (Baroni Urbani, 1964) in lateral (left), dorsal (center) and head view (right). Photos available on www.antweb.org, specimen identifiers in parentheses. 19– 21. Worker from Monte Pellegrino (Palermo mountains, Sicily) (ANTWEB1041536), photo by Enrico Schifani. 22–24. Paratype worker from Bosco di Santo Pietro (Hyblaean Sicily) (ANTWEB1041537), photo by Elia Nalini. 25–27. Worker from Bosco di Linera (Etna, Sicily) (ANTWEB1041538), photo by Enrico Schifani. 28–30. Queen from Bosco di Santo Pietro (type locality, Hyblaean Sicily) (ANTWEB1041539), photo by Enrico Schifani. 31–33. Male from Bosco di Santo Pietro (type locality, Hyblaean Sicily) (ANTWEB1041540), photo by Enrico Schifani. Scale bars = 0.5 mm.

Fig. 79. Maximum likelihood phylogeny inferred with IQTREE ver. 2.1.2. The major clades found in Prebus (2017) are highlighted, and the focal species of the current study (all within the ‘Palearctic clade IV’) are evidenced as in Figs 75–78. Maximum likelihood bootstrap support for all nodes are 100, except where indicated.

Figs 80–81. Geographic distribution of the four taxa treated in this study. Note that the shallow water area (light grey) between Sicily and the Maltese Islands roughly corresponded to a land bridge during glaciations.

Fig. 82. Spatial characterization of the sites where the four species treated in this study were found.