Royidris shuckardi

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Royidris shuckardi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Royidris
Species group: notorthotenes
Species: R. shuckardi
Binomial name
Royidris shuckardi
(Forel, 1895)

Monomorium shuckardi casent0010761 profile 1.jpg

Monomorium shuckardi casent0010761 dorsal 1.jpg

Specimen labels

Bolton and Fisher (2014) - This species is known only from the holotype queen. While it certainly belongs in Royidris, and because of its 4-segmented antennal club is referable to the notorthotenes group, it can not be matched with any other queen assigned to that group. In addition, as pointed out by Heterick (2006), its type-locality, Moramanga, is in Toamasina Province, hundreds of kilometers away from the range of, and with vegetation and conditions very different from, that inhabited by other species now in Royidris.


A member of the notorthotenes species group. Bolton and Fisher (2014) - Heterick (2006) associated the isolated shuckardi holotype queen with workers of what is now considered a complex of three worker-based species, Royidris gravipuncta, Royidris longiseta, and the more recently discovered Royidris peregrina. He grouped the first two species together with the isolated queen, and regarded them as a single species, to which he applied the name shuckardi. However, there is no evidence for this association. None of the few queens associated with, or assumed to belong to the same group as the three worker-based species, corresponds to the holotype of shuckardi. Heterick (2006) suggests that the locality given for the shuckardi queen may be in error. This could be correct, but even if true the queen can not be linked to any known species. Resolution of the identity of shuckardi will require the acquisition and comparison of more samples of worker-associated queens.

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



The holotype queen designated by Forel was matched with workers from different collection events by Heterick (2006). These worker specimens were later determined to be different Royidris species (see the identification section above). Monomorium shuckardi is currently known from the single holotype queen.


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

  • shuckardi. Monomorium shuckardi Forel, 1895c: 251 (w.) MADAGASCAR. Heterick, 2006: 95 (q.). Combination in M. (Notomyrmex): Emery, 1922e: 170; in Royidris: Bolton & Fisher, 2014: 65.

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



Heterick (2006) - Holotype: HML 3.16 HL 0.81 HW 0.88 CeI 109 SL 0.79 SI 89 PW 0.82.

HML 3.34 HL 0.88 HW 0.86 CeI 98 SL 0.74 SI 86 PW 0.76 (n=1).

(holotype).— HEAD: Head oval; vertex convex; frons shining and finely longitudinally striolate and microreticulate; 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; (in profile) eyes set posteriad of midline of head capsule.

MESOSOMA: Anterior mesoscutum smoothly rounded, thereafter more-or-less flattened; sides of mesoscutum and mesopleuron faintly longitudinally striolate, dorsum of mesoscutum mainly smooth; 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 a mixture of incurved, semi-erect setae and slightly shorter decumbent setae; appressed pronotal, mesoscutal and mesopleural setulae few, mainly on dorsum of pronotum and mesoscutum. Propodeum shining and densely striolate over whole surface; distinctly angulate, propodeal angle sharp; propodeal dorsum sloping posteriad, and depressed between raised propodeal angles; standing propodeal setae consisting of a few decumbent setae only; appressed propodeal setulae well-spaced and sparse; propodeal spiracle nearer metanotal groove than declivitous face of propodeum; propodeal lobes present as well-developed, rounded flanges.

WING: Wing not seen (queen dealated).

PETIOLE AND POSTPETIOLE: Petiolar spiracle lateral and situated slightly anteriad of petiolar node; node, 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 1:1. Anteroventral petiolar process present as a thin flange tapering posteriad; height ratio of petiole to postpetiole about 1:1; height–length ratio of postpetiole between 3:2 and 4:3; postpetiole shining and microreticulate; postpetiolar sternite not depressed, its anterior end an inconspicuous lip or small carina.

GASTER: Pilosity of first gastral tergite consisting of well-spaced, erect and semi-erect setae interspersed with a few appressed setulae.

GENERAL CHARACTERS: Color ferruginous. Brachypterous alates not seen. Ergatoid or worker female intercastes not seen.

Bolton and Fisher (2014) - (gyne). Alate when virgin. Among the few known queens of the gravipuncta complex, shuckardi is isolated because with its head in full-face view the eyes are located in front of the midlength of the sides, and the sides behind the eyes appear long and shallowly convex, convergent posteriorly through long, shallow curves, and with the posterior margin short and indented medially. In the worker-associated queen of peregrina, and the two unassociated queens that are known in the complex, the eyes are at, or very close to, the midlength, and the sides behind the eyes round through narrow curves into a broad posterior margin that is shallowly concave across its width.

Type Material

Heterick (2006) - Holotype: Madagascar, Moramanga, coll. [F.] Sikora (Musee d'Histoire Naturelle Genève). (NB. The symbol used in the original publication is that for the worker, but in fact, the specimen is a queen. That a dealated queen is here described rather than a worker is evident from Forel’s use of the term ‘scutellum’, and also his mention of propodeal ‘teeth’, which are not found in the worker. The total specimen length given by Forel for the type specimen agrees exactly with my own measurement, and given that there is no indication in the published description that any other specimens were examined by Forel, a holotype status fixed by monotypy (Code 73.1.2) is here assumed.).


  • 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
  • Emery, C. 1922c. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [part]. Genera Insectorum 174B: 95-206 (page 170, Combination in M. (Notomyrmex))
  • Forel, A. 1895d. Nouvelles fourmis de l'Imerina oriental (Moramanga etc.). Ann. Soc. Entomol. Belg. 39: 243-251 (page 251, worker described)
  • Heterick, B.E. 2006. A revision of the Malagasy ants belonging to genus Monomorium Mayr, 1855. Proceedings of the California Academy of Sciences. 57:69-202.
  • Wheeler, W. M. 1922k. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. IX. A synonymic list of the ants of the Malagasy region. Bull. Am. Mus. Nat. Hist. 4 45: 1005-1055 (see also)

References based on Global Ant Biodiversity Informatics

  • Fisher B. L. 1997. Biogeography and ecology of the ant fauna of Madagascar (Hymenoptera: Formicidae). Journal of Natural History 31: 269-302.
  • Fisher B. L. 2003. Formicidae, ants. Pp. 811-819 in: Goodman, S. M.; Benstead, J. P. (eds.) 2003. The natural history of Madagascar. Chicago: University of Chicago Press, xxi + 1709 pp.
  • Heterick B. 2006. A Revision of the Malagasy Ants Belonging to Genus Monomorium Mayr, 1855 (Hymenoptera: Formicidae). Proceeding of the California Academy of Sciences (PCAS) 57: 69-202
  • Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. IX. A synonymic list of the ants of the Malagasy region. Bulletin of the American Museum of Natural History 45: 1005-1055