Chelaner decuria

Chelaner decuria
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Solenopsidini
Genus:	Chelaner
Species group:	falcatus
Species:	C. decuria
Binomial name
Chelaner decuria (Heterick, 2001) Specimen Labels

This appealing little ant is inconspicuous, and probably more abundant than the distribution records suggest. (Heterick 2001)

Identification

Heterick (2001) - A member of the falcatus group. This is the only Australian Chelaner with 10-segmented antennae. Nonetheless, the form of the propodeum and of the body sculpture clearly places Chelaner decuria in the same species-group as Chelaner elegantulus, Chelaner falcatus and Chelaner lacunosus.

Heterick (2009) - Aside from members of some populations of putative Monomorium sydneyense, this is the only Australian Chelaner or Monomorium with a 10-segmented antenna.

Keys including this Species

• Key to Australian Monomorium Species

Distribution

Heterick (2009) - Confined to the south-west corner of WA, this species has a more localized distribution than most of the other members of its species group. However, it is easily the most common.

Latitudinal Distribution Pattern

Latitudinal Range: -31.9589° to -32.23332977°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Heterick (2001) - In southwestern Australia, the species occupies habitats ranging from wet sclerophyll forest to coastal Banksia and Dryandra scrubland.

I observed activity at a nest in semi-rural bush and parkland in Kwinana, Western Australia, where the ants were foraging nocturnally on sand with sparse ground cover. The workers moved very slowly across the ground surface. The entrance to the nest was a minute hole, barely larger than an individual worker. No excavated soil or other material could be seen around the nest.

Heterick 2009 - Occurs in woodlands, up to the outskirts of towns and cities, including the Perth metropolitan area.

Nomenclature

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

• decuria. Monomorium decuria Heterick, 2001: 379, figs. 24, 69 (w.) AUSTRALIA (Western Australia).
  • Type-material: holotype worker, 8 paratype workers.
  • Type-locality: holotype Australia: Western Australia, Kwinana, 31.i.1987, 125/6MonBH49 (B.E. Heterick); paratypes: Western Australia, Geraldton, 300mi. N Perth, ca 15 mi. inland, 300 ft (C. Mercovich).
  • Type-depositories: ANIC (holotype); BMNH, MCZC (paratypes).
  • Combination in Chelaner: Sparks, et al. 2019: 232.
  • Status as species: Heterick, 2009: 158; Sparks, et al. 2019: 232.
  • Distribution: Australia.

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 1.70; HL 0.69; HW 0.63: Cel 92; SL 0.43; SI 67; PW 0.39. Other. HML 1.41-1.83; HL 0.56-0.74; HW 0.52-0.72; Cel 92-97; SL 0.36-0.46; SI 65- 74; PW 0.28-0.41 (9 measured).

As for the worker of Chelaner falcatus, but with the following apomorphies.

Head. Frons of head capsule microreticulate and striolate with combination of appressed setulae and erect and suberect setae. (Viewed from front) compound eyes set at midpoint of each side of head capsule; (viewed laterally) compound eyes set posterior of midline ofhead capsule; eye moderate, eye width 0.5-1.5x greatest width of antennal scape. Antennal segments 10. Longest lateral anterior clypeal setae long, extending beyond dorsal margin of closed mandibles. Maximum number of mandibular teeth and denticles: five; mandibles (viewed from front) triangular and striate, with piliferous punctures; apical and basal mandibular margins meeting in tooth or denticle.

Alitrunk. Promesonotum with uniform microreticulation and dorsal foveae; evenly convex dorsally; erect and suberect promesonotal setae absent to >5; setulae appressed. Mesonotal suture absent. Metanotal groove absent. Propodeal processes present on posterior propodeal angles as small denticles or sharp flanges. Propodeal angle absent; propodeal setulae appressed.

Petiole and postpetiole. Ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) near 4:3. Anteroventral process always present as pronounced spur. Ventral lobe present in some individuals. Height-length ratio of postpetiole near 2:1 to near 4:3. Ventral process absent or vestigial.

General characters. Colour light brown, head and gaster darker, appendages tawny yellow. Worker caste monomorphic.

Type Material

Holotype. Worker, Western Australia, Kwinana, 31.i.l987, B. E. Heterick, soil, mixed native/ exotic veg., semi rural environment, 125/6MonBH49 (Australian National Insect Collection). Paratypes. Western Australia: 2x4 workers, Geraldton, 300 miles N of Perth, 22.v.l963, C. Mercovich, 300 ft., ca 15 miles inland, savannah woodland, 10 seg. antennae, Chelaner (The Natural History Museum and Museum of Comparative Zoology).

• Holotype, worker, Kwinana, Western Australia, Australia, Heterick,B.E., ANIC32-015726, Australian National Insect Collection.
• Paratype, 4 workers, Geraldton, Western Australia, Australia, The Natural History Museum.
• Paratype, 4 workers, Geraldton, Western Australia, Australia, Museum of Comparative Zoology.

Etymology

Latin: “division of ten”.

References

• Heterick, B. E. 2001. Revision of the Australian ants of the genus Monomorium (Hymenoptera: Formicidae). Invertebrate Taxonomy. 15:353-459. (page 379, figs. 24, 69 worker described)
• Heterick, B. E. 2009. A guide to the ants of South-western Australia. Records of the Western Australian Museum, Supplement 76:1-206.
• Heterick, B.E. 2021. A guide to the ants of Western Australia. Part I: Systematics. Records of the Western Australian Museum, Supplement 86, 1-245 (doi:10.18195/issn.0313-122x.86.2021.001-245).
• Heterick, B.E. 2022. A guide to the ants of Western Australia. Part II: Distribution and biology. Records of the Western Australian Museum, supplement 86: 247-510 (doi:10.18195/issn.0313-122x.86.2022.247-510).
• Sparks, K. 2015. Australian Monomorium: Systematics and species delimitation with a focus of the M. rothsteini complex. Ph.D. thesis, University of Adelaide.
• Sparks, K.S., Andersen, A.N., Austin, A.D. 2019. A multi-gene phylogeny of Australian Monomorium Mayr (Hymenoptera : Formicidae) results in reinterpretation of the genus and resurrection of Chelaner Emery. Invertebrate Systematics 33: 225–236 (doi:10.1071/IS16080).

References based on Global Ant Biodiversity Informatics

• Heterick B. E. 2001. Revision of the Australian ants of the genus Monomorium (Hymenoptera: Formicidae). Invertebrate Taxonomy 15: 353-459.
• Heterick B. E. 2009. A guide to the ants of south-western Australia. Records of the Western Australian Museum Supplement 76: 1-206.