Romblonella

Romblonella
Romblonella opaca
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Crematogastrini
Genus:	Romblonella Wheeler, W.M., 1935
Type species
Romblonella grandinodis (junior synonym of Romblonella opaca)
Diversity
10 species (Species Checklist, Species by Country) Romblonella opaca Specimen Label

Evolutionary Relationships

Cardiocondyla Ocymyrmex Nesomyrmex Xenomyrmex Terataner Atopomyrmex Cataulacus Carebara Diplomorium Melissotarsus Rhopalomastix Calyptomyrmex Tetramorium Cyphoidris Dicroaspis Aretidris Vollenhovia Dacetinops Indomyrma Crematogaster Meranoplus Lophomyrmex Adlerzia Recurvidris Stereomyrmex Trichomyrmex Eutetramorium Royidris Malagidris Vitsika Huberia Podomyrma Liomyrmex Metapone Kartidris Mayriella Tetheamyrma Dacatria Proatta Dilobocondyla Secostruma Acanthomyrmex Myrmecina Perissomyrmex Pristomyrmex some Lordomyrma Propodilobus Lasiomyrma [some Lordomyrma Ancyridris some Lordomyrma Paratopula Poecilomyrma Romblonella Rotastruma Gauromyrmex Vombisidris Temnothorax Harpagoxenus Formicoxenus Leptothorax

Based on Ward et al. (2014) and Blaimer et al. (2018).

Most species have a very limited range, are rarely collected, and are known from only a few collections. Romblonella opaca is the exception. It is relatively widespread, known from small collections (1-5 workers) from four islands in the Philippines and its type locality in Indonesia.

Identification

Characterized by a robust, hard and compact body, stout propodeal spines, massive petiole and postpetiole, and gaster formed largely by the first tergite.

Taylor (1991) for the synonymized Willowsiella - Stereomyrmex and Romblonella share several features considered to indicate relationship between them. These include the general configuration of the mesosoma and nodes (despite the differences in the latter), and the fundamentally similar dental, fronto-clypeal, palpal and sting structures (the latter at least as visible without dissection). The two genera may be readily distinguished as follows:

Stereomyrmex - Antennae 11-jointed. Fronto-clypeal area strongly inflated. Antennal scrobes lacking. Petiole massively inflated (in S. dispar ), or somewhat scale-like and transverse (in S. anderseni). Postpetiole relatively small compared to petiole, transverse, and somewhat scale-like. Gaster emarginate at base, following the posterior outline of the postpetiole when viewed from above.

Romblonella - Antennae 12-jointed. Fronto-clypeal area unexceptionally inflated. Antenna scrobes strongly developed. Petiole somewhat globular but not unexceptionally inflated or transverse. Postpetiole of more normal proportions, subspherical, more-or-less as long as wide in dorsal view, at most only slightly smaller than petiole; usually larger. Gaster not basally emarginate.

Keys including this Genus

• Key to Australian Genera of Myrmicinae

 

Biology

Life History Traits

• Mean colony size: ? (Greer et al., 2021)
• Compound colony type: not parasitic (Greer et al., 2021)
• Nest site: arboreal (Greer et al., 2021)
• Diet class: ? (Greer et al., 2021)
• Foraging stratum: subterranean/leaf litter; arboreal (Greer et al., 2021)

Morphology

Worker Morphology

• Antennal segment count: 12 • Antennal club: 3 • Palp formula: 5,3 • Spur formula: 0, 0 • Eyes: >100 ommatidia • Pronotal Spines: absent • Mesonotal Spines: absent • Propodeal Spines: present • Petiolar Spines: absent • Caste: none or weak • Sting: present • Metaplural Gland: present • Cocoon: absent

Male Morphology

 • Antennal segment count 13 • Antennal club 0 • Palp formula 5,3 • Total dental count 6-7 • Spur formula 0, 0 • Notes: from literature

Nomenclature

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

• ROMBLONELLA [Myrmicinae: Formicoxenini]
  • Romblonella Wheeler, W.M. 1935a: 5. Type-species: Romblonella grandinodis (junior synonym of Myrmica opaca), by original designation.

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

Description

Worker

Monomorphic, stout and thickset; integument hard, thick, very coarsely sculptured. Head subrectangular, with moderately large, convex eyes at the middle of the sides. Ocelli absent. Mandibles short, subtriangular, with strong, subequal teeth. Clypeus short and depressed on the sides, with broad, antero-posteriorly convex median portion, extending back between the frontal carinae, the anterior border without teeth. Frontal carinae widely separated, somewhat lobular and horizontal anteriorly, continued back to within a short distance of the posterior corners of the head as a pair of sharp, diverging ridges which form the mesial borders of distinct but shallow scrobes. Frontal area distinct but shallow; frontal groove absent. Antennae short, 12-jointed; funiculi enlarged toward the tip, forming a very distinct 3-jointed club which is as long as the remainder of the funiculus, first funicular joint enlarged, nearly twice as long as broad, joints 2-8 short and transverse. Thorax stout, evenly convex above, without promesonotal and mesoepinotal sutures. Epinotum armed with a pair of long spines, which are placed rather low. Petiole and post-petiole very large, nodiform, the former narrowed and subpedunculate anteriorly. Gaster broadly elliptical, formed very largely by the first segment. Sting small. Coxae small, legs stout, middle and hind tibiae spurless; tarsal claws simple.

References

• Bolton, B. 1994. Identification guide to the ant genera of the world. Cambridge, Mass.: Harvard University Press, 222 pp. (page 105, Romblonella in Myrmicinae, Formicoxenini)
• Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 251, Romblonella in Myrmicinae, Formicoxenini)
• Cantone S. 2018. Winged Ants, The queen. Dichotomous key to genera of winged female ants in the World. The Wings of Ants: morphological and systematic relationships (self-published).
• Dlussky, G. M.; Fedoseeva, E. B. 1988. Origin and early stages of evolution in ants. Pp. 70-144 in: Ponomarenko, A. G. (ed.) Cretaceous biocenotic crisis and insect evolution. Moskva: Nauka, 232 pp. (page 80, Romblonella in Myrmicinae, Meranoplini)
• Hölldobler, B.; Wilson, E. O. 1990. The ants. Cambridge, Mass.: Harvard University Press, xii + 732 pp. (page 16, Romblonella in Myrmicinae, Meranoplini)
• Smith, M. R. 1953a. A revision of the genus Romblonella W. M. Wheeler (Hymenoptera: Formicidae). Proc. Hawaii. Entomol. Soc. 15: 75-80 (page 163, Romblonella in Myrmicinae, Myrmecinini)
• Taylor, R. W. 1991a [1990]. Notes on the ant genera Romblonella and Willowsiella, with comments on their affinities, and the first descriptions of Australian species (Hymenoptera: Formicidae: Myrmicinae). Psyche (Camb.) 97: 281-296 (page 294, Romblonella in Myrmicinae, Leptothoracini)
• Wheeler, W. M. 1935a. Two new genera of myrmicine ants from Papua and the Philippines. Proc. N. Engl. Zool. Club 15: 1-9 (page 5, 6, Romblonella in Myrmicinae, Meranoplini (in key))