Royidris longiseta

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Royidris longiseta
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Royidris
Species group: notorthotenes
Species: R. longiseta
Binomial name
Royidris longiseta
Bolton & Fisher, 2014

Royidris longiseta casent0078298 p 1 high.jpg

Royidris longiseta casent0078298 d 1 high.jpg

Specimen Labels

Only four specimens are referable to this species, one collected from a pitfall trap in spiny forest, two from urban gardens, and one in shrubland. In the paratype and the non-paratypic workers some suberect pubescence is present on the side of the head below the eye, which may be visible in full-face, projecting from below the eye. This feature is absent from the holotype, and its significance is not understood at present.


A member of the notorthotenes species group. Bolton and Fisher (2014) - The holotype of this species was included as part of Royidris shuckardi by Heterick (2006). R. longiseta is closest related to Royidris gravipuncta, but has distinctly longer promesontal and gastral setae, and also has short erect setae present on the propodeal dorsum.

Keys including this Species


Endemic to Madagascar.

Distribution based on Regional Taxon Lists

Malagasy Region: Madagascar (type locality).

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb



Known only from the worker caste.


The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • longiseta. Royidris longiseta Bolton & Fisher, 2014: 55, figs. 57-59, Map 141 (w.) MADAGASCAR.

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



(holotype in parentheses). TL 2.7–3.0 (2.7), HL 0.64–0.67 (0.66), HW 0.54–0.56 (0.54), CI 82–84 (82), SL 0.54–0.59 (0.59), SI 100–109 (109), PW 0.36–0.38 (0.36), WL 0.80 – 0.82 (0.80) (3 measured).

Antennal club 4-segmented. Mandible longitudinally costulate. Scapes of moderate relative length (SI 100–109); when laid straight back in full-face view the apex of the scape slightly exceeds the posterior margin of the head. With head in full-face view the eyes very close to the midlength of the side of the head capsule. EL 0.16–0.18 (EL/HW 0.30–0.33). Dorsum of head from level of eyes to posterior margin finely reticulate-punctate, the sculpture uniform, effaced in places, or fading out posteriorly. Promesonotum in profile convex and swollen, the mesonotum posteriorly descends abruptly to a small, weakly incised metanotal groove. In absolute profile the propodeal dorsum is horizontal and flat, or very nearly flat; posteriorly dorsum meets the declivity in a rounded right-angle and the declivity is straight and almost vertical. 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 4–5 pairs of setae; mesonotum with 3–4 pairs; on both pronotum and mesonotum the longest setae are longer than the maximum vertical diameter of the eye. Dorsum of propodeum with 2–3 pairs of short, standing setae that are less then half the length of those on the mesonotum. Petiole node with 3–4 pairs of setae that arise from the apex and posterior face of the node; postpetiole with numerous long setae that arise from the anterior, dorsal and posterior surfaces of the node; first gastral tergite with numerous long, suberect setae that are at least subequal to the maximum vertical diameter of the eye. Entire dorsum of mesosoma finely and densely reticulate-punctate in type-material, the sculpture of about equal density and intensity everywhere, or weaker on the pronotum (superficial on pronotum in the non-paratypic specimens). Pronotum also with weak transverse striolae in the type-series, but not in the non-paratypic workers. Entire side of mesosoma finely and densely reticulate-punctate, the sculpture of approximately equal density and intensity everywhere in the paratype, but weaker on the pronotum than the mesopleuron in the holotype and partially effaced in the non-paratypic workers. Metafemur with MfL 0.55–0.58 (MfL/HW 1.02–1.07, MfL/MfH 3.63–3.73). Postpetiole relatively narrow in dorsal view, maximum width 0.20–0.21 (0.36–0.39 × HW). First gastral tergite glassy smooth, without trace of superficial microreticulate sculpture. Colour of mesosoma, petiole and postpetiole brown to orange-brown, the head somewhat darker than the mesosoma; the gaster glossy dark brown to black.

Type Material

Holotype worker, Madagascar: Prov. Toliara, Mahafaly Plateau, 6.2 km. 74° ENE Itampolo, 24°39’S, 43°69’E, 80 m., 21-25.ii.2002, BLF 5763, CASENT0078298, pitfall trap, spiny forest/thicket (Fisher et al.) (California Academy of Sciences). Paratype. 1 worker, Prov. Toliara, Tsivory, 24°04.24’S, 46°04.52’E, 400 m., 9.xii.2006, BLF 15869, CASENT0120216, urban/garden (Fisher et al.) (CASC).


  • 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

References based on Global Ant Biodiversity Informatics

  • Bolton B., and B. L. Fisher. 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): 1-99.