Polyrhachis johnsoni

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Polyrhachis johnsoni
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Camponotini
Genus: Polyrhachis
Subgenus: Cyrtomyrma
Species: P. johnsoni
Binomial name
Polyrhachis johnsoni
Mann, 1919

Polyrhachis johnsoni casent0903408 p 1 high.jpg

Polyrhachis johnsoni casent0903408 d 1 high.jpg

Specimen Labels

Mann (1919) reported a colony was found in a silk and carton nest on a palm leaf.

Identification

Polyrhachis johnsoni was originally described as a variety of Polyrhachis rastellata, but was treated by Donisthorpe (1938) as a variety of Polyrhachis debilis. Polyrhachis johnsoni is certainly more closely related to Polyrhachis debilis than to Polyrhachis rastellata but can be easily distinguished from both by the outline of pronotum. In Polyrhachis johnsoni the pronotal dorsum is rather flat, while it is distinctly convex in the other two species. From Polyrhachis rastellata it also differs by the presence of distinct, though short, propodeal spines or tubercles. From Polyrhachis debilis it differs primarily by its distinctly larger size (HL 1.72-1.87 in Polyrhachis johnsoni syntypes versus 1.34-1.47 in Polyrhachis debilis syntypes) and by the propodeal declivity that is almost as high as the full height of the petiole. In Polyrhachis debilis the propodeal declivity is relatively low, with its dorsal margin barely reaching the level of the bases of the dorsal petiolar teeth. (Kohout 2006)

Keys including this Species

Distribution

The known distribution of Polyrhachis johnsoni appears to be limited the Solomon Islands, but there are a few unconfirmed records from the East Britain Province of Papua New Guinea. (Kohout 2006)

Distribution based on Regional Taxon Lists

Indo-Australian Region: Solomon Islands (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Nomenclature

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

  • johnsoni. Polyrhachis (Cyrtomyrma) rastellata var. johnsoni Mann, 1919: 390 (w.) SOLOMON IS. Subspecies of debilis: Donisthorpe, 1938c: 266. Raised to species: Kohout, 2006b: 140.

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

Description

Worker

Length 7 mm.

Resembling laevior var. debilis Emery in having on the epinotum a pair of distinct though very short and small spines. It is much larger in size than debilis and the legs are uniformly dark brown, almost black. The thorax is evenly arched, much as in leonidas Forel and the epinotal declivity in profile is straight.

Type Material

Syntype workers Museum of Comparative Zoology, National Museum of Natural History and The Natural History Museum - as reported by Kohout (2006).

Type Locality Information

SOLOMON IS., Rendova, col. W.M. Mann.

References

Kohout, R. J. 2006. Review of Polyrhachis (Cyrtomyrma) Forel (Hymenoptera: Formicidae: Formicinae) of Australia, Borneo, New Guinea and the Solomon Islands with descriptions of new species. Memoirs of the Queensland Museum. 52:87-146.

Mann, W.M. 1919. The ants of the British Solomon Islands. Bulletin of the Museum of Comparative Zoology at Harvard College 63: 273-391.