Royidris notorthotenes

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Royidris notorthotenes
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Royidris
Species group: notorthotenes
Species: R. notorthotenes
Binomial name
Royidris notorthotenes
(Heterick, 2006)

Monomorium notorthotenes casent0002259 profile 1.jpg

Monomorium notorthotenes casent0002259 dorsal 1.jpg

Specimen labels

All samples of notorthotenes are from spiny forest. They have been discovered nesting under stones and foraging on the ground, and have also been retrieved from pitfall traps.

Identification

Superficially, workers of this species may be confused with Aphaenogaster because of their elongate bodies and spindly appendages.

A member of the notorthotenes species group. Bolton and Fisher (2014) - R. notorthotenes is part of a small complex, which also includes Royidris diminuta and Royidris etiolata, together characterised by a 4-segmented antennal club in which funicular segments 8 and 9 are of equal length, uniform yellow colour, and cephalic sculpture that is weak to vestigial. They all have relatively long scapes (SI 115–158), a head that averages relatively narrow (CI 75–84), and long metafemora (MfL/HW 1.25–1.50). Morphologically, these three species are strikingly similar, but their workers can be separated by their relative dimensions, as discussed under diminuta and etiolata.

Keys including this Species

Distribution

Endemic to Madagascar.

Distribution based on Regional Taxon Lists

Malagasy Region: Madagascar (type locality).

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Royidris notorthotenes for further details

Biology

Castes

Worker

Queen

Male

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • notorthotenes. Monomorium notorthotenes Heterick, 2006: 91, figs. 14, 85 - 89 (w.q.m.) MADAGASCAR. Combination in Royidris: Bolton & Fisher, 2014: 57.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Holotype: HML 2.77 HL 0.88 HW 0.76 CeI 86 SL 0.86 SI 113 PW 0.49. HML 2.39–2.80 HL 0.75–0.90 HW 0.62–0.78 CeI 81–86 SL 0.82-0.96 SI 115–132 PW 0.42–0.50 (n=20).

HEAD: Head rectangular; vertex planar; frons shining and finely striolate and microreticulate; pilosity of frons consisting mainly of short, appressed setulae with a few stout, erect and semi-erect setae on vertex. Eye large, eye width 1.5× greater than greatest width of antennal scape; (in full-face view) eyes set at about midpoint of head capsule; (viewed in profile) eyes set around midline of head capsule; eye elliptical, curvature of inner eye margin may be more pronounced than that of its outer margin. Antennal segments 12; antennal club four-segmented. Clypeal carinae indistinct; anteromedian clypeal margin broadly convex; paraclypeal setae moderately long and fine, curved; posteromedian clypeal margin approximately level with antennal fossae. Anterior tentorial pits situated nearer antennal fossae than mandibular insertions. Frontal lobes sinuate, divergent posteriad. Psammophore absent. Palp formula 5,3. Mandibular teeth five; mandibles triangular and striate; masticatory margin of mandibles approximately vertical or weakly oblique; basal tooth approximately same size as t4 (five teeth present).

MESOSOMA: Promesonotum shining and microreticulate throughout; (viewed in profile) promesonotum broadly convex; promesonotal setae seven to twelve; standing promesonotal setae consisting of short, erect or semi-erect bristles; appressed promesonotal setulae well-spaced over entire promesonotum. Metanotal groove weakly impressed, with faint costulae or costulae lacking. Propodeum shining and microreticulate; propodeal dorsum convex; propodeum smoothly rounded or with indistinct angle, but dorsal and declivitous faces separated when seen in profile; standing propodeal setae absent; appressed propodeal setulae abundant, particularly on dorsum of propodeum; propodeal spiracle equidistant from metanotal groove and declivitous face of propodeum. Vestibule of propodeal spiracle absent or not visible. Propodeal lobes present as rounded flanges.

PETIOLE AND POSTPETIOLE: Petiolar spiracle laterodorsal and situated well anteriad of petiolar node; node (viewed in profile) conical, vertex tapered; appearance of node shining and distinctly microreticulate; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) between 1:1 and 3:4; anteroventral petiolar process absent or vestigial; ventral petiolar lobe absent; height ratio of petiole to postpetiole between 1:1 and 3:4; height–length ratio of postpetiole between 1:1 and 3:4; postpetiole shining and microreticulate; postpetiolar sternite not depressed at midpoint, its anterior end an inconspicuous lip or small carina.

GASTER: Pilosity of first gastral tergite consisting of well-spaced, short, thick, erect setae interspersed with minute, appressed setulae.

GENERAL CHARACTERS: Color depigmented ochre. Worker caste monomorphic.

Bolton and Fisher (2014) - TL 3.6–4.3, HL 0.80–0.98, HW 0.65–0.81, CI 78–84, SL 0.86–1.00, SI 115–132, PW 0.43–0.51, WL 1.02–1.34 (20 measured).

Antennal club 4-segmented, funicular segments 8 and 9 of equal length. Mandible longitudinally costulate. Scapes relatively long (SI 115–132); when laid straight back in full-face view the apex of the scape very obviously exceeds the posterior margin of the head. With head in full-face view the eyes at the midlength of the side of the head capsule. EL 0.20–0.24 (EL/HW 0.29–0.32). Dorsum of head from level of eyes to posterior margin almost smooth, with only faint, superficial remnants of reticulate or feeble, disorganised punctulate sculpture. Promesonotum in profile convex and swollen, the mesonotum with a long posterior slope that descends to the very feebly indicated metanotal groove. In absolute profile the propodeal dorsum is horizontal, flat to very nearly flat, posteriorly with a bluntly rounded angle. The whole propodeal dorsum is strongly depressed with respect to the highest point of the promesonotum, which is on a considerably higher level. Pronotum with 3–5 pairs of setae; mesonotum with 2–3 pairs; dorsum of propodeum lacks standing setae. Pronotal dorsum usually with weak, superficial reticulate-punctulate sculpture, at least near the midline; sometimes the sculpture reduced to microreticulation, but the surface never entirely smooth and polished. Propodeal dorsum very finely and densely reticulate-punctulate, the sculpture usually more distinct than on the pronotal dorsum. Side of pronotum superficially microreticulate to weakly reticulate-punctulate; mesopleuron and metapleuron finely and densely reticulate-punctate. Metafemur appears strongly incrassate, with MfL 0.88–1.10 (MfL/HW 1.28–1.39, MfL/MfH 3.62–4.15). Petiole with one pair of setae, on its posterior face near the base; postpetiole with setae on its dorsal and posterior faces; first gastral tergite with numerous suberect setae that are shorter than the maximum vertical diameter of the eye. Postpetiole relatively narrow in dorsal view, maximum width 0.20–0.24 (ca 0.30 × HW). Dorsum of postpetiole with very weak reticulate-punctulate or superficial granulate sculpture, sometimes vestigial. First gastral tergite unsculptured, or at most with traces of superficial microreticulate patterning. Entirety of head, mesosoma, petiole, postpetiole, legs and gaster yellow.

Queen

HML 3.98–4.39 HL 1.14–1.21 HW 1.11–1.23 CeI 95–103 SL 1.00–1.09 SI 85–98 PW 0.90–1.04 (n=13).

HEAD: Head rectangular; vertex always planar; frons shining and smooth except for piliferous pits; pilosity of frons a mixture of well-spaced, distinctly longer erect and semi-erect setae interspersed with shorter setae or setulae, which are decumbent or appressed, longer setae thickest on vertex. Eye elliptical, curvature of inner eye margin may be more pronounced than that of its outer margin;. (in full-face view) eyes set at about midpoint of head capsule; (viewed in profile) eyes set posteriad of midline of head capsule.

MESOSOMA: Mesoscutum broadly convex anteriad, convexity reduced posteriad; pronotum, mesoscutum and mesopleuron shining and mainly smooth, vestigial striolae, if present, confined to anterior katepisternum; length–width ratio of mesoscutum and scutellum combined between 2:1 and 3:2; axillae narrowly separated (i.e., less than width of one axilla); standing pronotal/mesoscutal setae consisting of well-spaced, incurved, erect and semi-erect setae only; appressed pronotal, mescoscutal and mesopleural setulae few, mainly on dorsum of pronotum and mesoscutum. Propodeum shining and microreticulate; propodeum distinctly angulate, propodeal angles produced as short denticles; propodeal dorsum sloping posteriad, and depressed between raised propodeal angles; standing propodeal setae absent; appressed propodeal setulae very sparse or absent; propodeal spiracle equidistant from metanotal groove and declivitous face of propodeum; propodeal lobes present as vestigial flanges only, or absent.

WING: Wing veins tubular and strongly sclerotised; vein m–cu present as an entire vein enclosing first discoidal cell; vein cu–a present.

PETIOLE AND POSTPETIOLE: Petiolar spiracle lateral and situated well anteriad of petiolar node; node (viewed in profile) cuneate, vertex tapered; appearance of node shining and microreticulate; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) about 4:3; anteroventral petiolar process absent or vestigial; height ratio of petiole to postpetiole about 1:1; height–length ratio of postpetiole between 4:3 and 1:1; postpetiole shining and microreticulate; postpetiolar sternite not depressed, in form of narrow, rectangular projection.

GASTER: Pilosity of first gastral tergite consisting of well-spaced, short, thick, erect setae interspersed with minute, appressed setulae.

GENERAL CHARACTERS: Color brownish- yellow, gaster darker. Brachypterous alates not seen. Ergatoid or worker-female intercastes not seen.

Bolton and Fisher (2014) - Alate when virgin. Much larger than worker. TL 6.4–7.1, HL 1.24–1.26, HW 1.16–1.22, CI 94–97, SL 1.02–1.04, SI 84–89, PW 0.88–1.02, WL 2.06–2.14, EL 0.36–0.38 (EL/HW 0.30–0.32), MfL 1.20–1.26 (MfL/HW 1.00–1.07, MfL/MfH 4.20–4.40), maximum dorsal length of mesoscutum 1.00–1.05, maximum width of mesoscutum 0.95–1.07, maximum dorsal width of postpetiole 0.42–0.48 (0.38–0.39 × HW) (5 measured).

Head somewhat more strongly sculptured than in worker, and with weak longitudinal costulae in front of the ocelli. Mesoscutum unsculptured except for minute, widely scattered pits; mesoscutellum unsculptured, smooth. Propodeal dorsum with fine transverse costulae, between which are traces of superficial punctulation. Petiole, and postpetiole finely reticulate-punctate. First gastral tergite unsculptured, or with superficial vestiges of faint microreticular patterning. Side of mesosoma mostly smooth, with scattered patches of minute weak punctulae or microreticulation. Propodeum rounded to very bluntly and obtusely angular posteriorly, without a well-defined tooth or dentiform angle between dorsum and declivity. All dorsal surfaces except propodeum with numerous fine setae; propodeum entirely lacks setae. Colour generally as in worker, but apex of each gastral tergite with a darker transverse band.

Male

HML 2.01–2.23 HL 0.46–0.53 HW 0.48–0.54 CeI 94–106 SL 0.11–0.14 SI 21–26 PW 0.58–0.71 (n=15).

HEAD: (In full-face view) head width-mesosoma width ratio between 4:3 and 1:1; frons finely micropunctate. Compound eyes protuberant and elliptical; margin of compound eye clearly separated from posterior margin of clypeus. Ocelli turreted. Ratio of length of first funicular segment of antenna to second funicular segment between 2:3 and 1:2. Maximum number of mandibular teeth and denticles three.

MESOSOMA: Mesoscutum broadly convex; pronotum and mesoscutum shining and mainly smooth, vestigial striolae, if present, confined to lower katepisternum; parapsidal furrows vestigial or absent; notauli absent; axillae separated by width of at least one axilla.

WING: Wing veins tubular and strongly sclerotised; vein m–cu absent; vein cu–a present.

PETIOLE AND POSTPETIOLE: Petiolar spiracle lateral and situated slightly anteriad of petiolar node; node (viewed in profile) evenly tumular; appearance of node shining and smooth; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) between 4:3 and 1:1; anteroventral petiolar process absent or vestigial; height ratio of petiole to postpetiole about 1:1; height–length ratio of postpetiole about 3:4; postpetiole shining and smooth.

GASTER: Pilosity of first gastral tergite consisting of well-spaced, semi-erect setae.

GENERAL CHARACTERS: Color a depigmented ochre.

Type Material

HOLOTYPE: worker, Prov. Toliara, Rés Cap Sainte Marie 14.9 km 261 W Marovato 25°36′S, 45°09′Ε, 160 m. 13–19.ii.2002, Fisher et al. BLF# 5740/under stone spiny forest/thicket/ CASENT 0002257 (California Academy of Sciences). PARATYPES: Prov. Toliara (all specimens with same collection data as holotype): 1×2 worker (one with head missing) (Australian National Insect Collection); 1×2 worker (The Natural History Museum); 1 queen + 2 males (5741) (CAS); 2 workers + 1queen (Museum of Comparative Zoology).

Etymology

Greek ‘noton’ (neut. ‘back’) + ‘orthotenes’ (‘stretched out’)

References

  • Bolton, B. & Fisher, B.L. 2014. The Madagascan endemic myrmicine ants related to Eutetramorium (Hymenoptera: Formicidae): taxonomy of the genera Eutetramorium Emery, Malagidris nom. n., Myrmisaraka gen. n., Royidris gen. n., and Vitsika gen. n. Zootaxa 3791:1–99. doi:10.11646/zootaxa.3791.1.1