Strumigenys itannae, dos Santos-Neto & Chaul & Delabie, 2024

dos Santos-Neto, Esperidião Alves, Chaul, Júlio Cezar Mário & Delabie, Jacques Hubert Charles, 2024, New Species and New Records of Strumigenys Smith, 1860 (Formicidae: Myrmicinae) from the Neotropical schulzi Species Group, Taxonomy (New York) 4 (3), pp. 633-648 : 637-639

Strumigenys itannae sp. nov. Santos-Neto, Chaul and Delabie

( Figure 1 )

Type material. Holotype worker: PERU. Madre de Dios: Reserva Nacional Tambopata, Sachavacayoc , − 12.855896 − 69.361939, 19–31.vii.2012, Winkler trap (Feitosa, R.; Probst, R.; Camacho, G.; Chaul, J.) [ CELC, ANTWEB1032113 ]. Paratype worker. BRAZIL. Rondônia: Jaci-Paraná, − 9.451220 − 64.376030, 01–27.i.2013, Winkler trap (Fernandes, I.) [ INPA, ANTWEB1032003 ] .

Non-type material. One worker with the head missing; sample data as holotype [ CELC, UFV-LABECOL-001540] .

Diagnosis. Basal lamella of mandible triangular, without diastema between it and masticatory margin; head dorsum with several erect hairs that gradually change from smaller, suberect and spatulate; eyes large, with 18–20 ommatidia in total; and stand pilosity simple, stiff, without ground pilosity contrasting to them. Mesosoma, petiole and postpetiole disc entirely and deeply reticulate-punctate; gaster first tergite smooth, except for basigastral costulae.

Geographical Distribution. Brazil (Rondônia); Peru (Madre de Dios). ( Figure 2 )

Description. Holotype. HW 0.39, ML 0.08, ML2 0.1, HL 0.51, SL 0.21, OL 0.06, ON 20, WL 0.53, PetL 0.25, A3 + A4L 0.48, PrW 0.28, DPetW 0.13, DPetndL 0.11, PosPetW 0.22, GW 0.36, MtfmL 0.35, MttbL 0.25, MtbtL 0.18, CI 81, SI 53, MI 20, TL 1.88. Paratype. HW 0.39, ML 0.08, ML2 0.1, HL 0.48–0.51, SL 0.21, OL 0.06, ON 18, WL 0.51, PetL 0.26, A3 + A4L 0.46, PrW 0.28, DPetW 0.13, DPetndL 0.10, PosPetW 0.22, GW 0.36, MtfmL 0.33, MttbL 0.24, MtbtL 0.17, CI 77, SI 53, MI 20, TL 1.81. Head. Basal lamella of mandible triangular followed by a total of 12 teeth; basal seven more developed than the apical five; teeth one and two somewhat blunt, the first being more than the latter; tooth three acute and the largest; teeth four to seven subequal and similar in shape to two. Apical five teeth divided into four tiny denticles, and the apical one, which is slightly more developed. Dorsal surface of mandibles covered with tiny, flattened, appressed hairs. Basiventral mandible gland visible ( Figure 1 A ). Clypeal anterior margin is overall convex, the medial section flat with freely projecting spoon-shaped hairs that are more flattened laterally; the posterior clypeal margin (epistomal sulcus) with an arch of suberect hairs, other hairs on the dorsum of clypeus appressed, spoon-shaped and smaller. Clypeus surface slightly raised in relation to the head surface posterad. Head dorsum with several erect hairs that gradually change from smaller, suberect and spatulate anteriorly to longer, thinner and erect posteriorly ( Figure 1 B ). Eyes well-developed, with 18 to 20 ommatidia. Scrobe well delimited and shallowly concave. Preocular carina well-developed and reaches the level of the eye. In full-face view, lateral margins of the head (dorsal scrobe margins) abruptly diverge posteriorly to the antennal insertions, the margins shelf-like, conspicuous translucent with backlighting. Antennae 6-segmented. Scape flattened, anterior margin with a well-developed sub-basal curvature and a row of freely projecting setae that vary from spoon-shaped basally to thinner apically, the first one or two proximal to the sub-basal bent are slightly curved apically, the four distal to these two curves to the base of scape and the distal two or three curved to the apex of the scape. Scape apicoventral gland visible. The head and dorsal surface of the scapes reticulate. Mesosoma. Entirely deeply reticulate-punctate. In profile, dorsal outline of promesonotum convex, metanotal impression poorly developed, dorsum of propodeum roughly straight; propodeal spine long and posteriorly and slightly dorsally directed; and propodeal lamella as thick as or slightly thicker than the propodeal spiracle diameter, without any lobe or indentation on its lower portion. Dorsally on mesosoma, various, simple, suberect to erect setae, of which the humeral pair and two pairs of lateral mesonotal setae are slightly longer than the remaining ones ( Figure 1 C ). Mesopleural excavations without a conspicuous patch of small setae. Legs with suberect, slightly curved, simple to slightly remiform setae. Femora, especially meso- and metafemora, robust. Anteroproximal surface of procoxa shallowly concave, with somewhat longer setae. Protibial apical gland visible, as well as patches similar on the basitarsi of all the legs. Metasoma. In dorsal view, the petiole node and postpetiole disc reticulate-punctate, latter with shallow, superimposed rugulae; petiole node slightly broader than long; and postpetiole disc more than twice as large as long ( Figure 1 C, D ). Spongiform tissue absent ventrally on the petiole, present as a thin, transversal lamella on posterior edge of petiole node, thicker laterally than medially; ventrally on postpetiole, two thick ventrolateral triangular outgrowths are linked medially by a thinner strip ( Figure 1 C ); dorsally on postpetiole, an anterior thin lamella and a posterior lamella that is medially thin and posterolaterally enlarged; a transversal lamella on the anterior edge of first gaster tergite. Specialized basigastral ventral setae arranged as a thin transversal band, hyphae-like. Gaster smooth, except for well-marked basigastral costulae, which are slightly smaller than postpetiole disc length ( Figure 1 D ). Erect, simple setae scattered on the dorsum of the metasoma.

Etymology. The specific epithet honours the Brazilian myrmecologist Itanna Oliveira Fernandes from the Instituto Nacional de Pesquisas da Amazônia– INPA.

Biology. The species has been sampled in the leaf litter by Winkler extractors twice in localities separated by almost 700 km in the catchment of the Madeira River.

Comments: Strumigenys itannae slightly resembles S. schulzi , S. castanea , S. metrix and S. orchibia within the schulzi group, but it can be easily isolated by the quantity of erect hairs on the vertex and mesosoma. The shape of the petiolar node is similar to that of S. schulzi and S. castanea , but it can be distinguished from these two additionally by the larger propodeal spine size and thinner, observed from the reduced propodeal lamella ( Table 1 ).

Figures

Figure 1. Strumigenys itannae sp. nov., holotype worker, head in full-face view (A), lateral view (B), dorsal view (C), gaster in dorsal view with basigastral costulae in detail. (D). [ANTWEB1032113]. Scale bars are 0.2 mm.

Figure 2. Distribution of the new species and new records for previously described species of the schulzi group.