Polyrhachis constructor

Polyrhachis constructor
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Formicinae
Tribe:	Camponotini
Genus:	Polyrhachis
Subgenus:	Myrmatopa
Species group:	flavicornis
Species:	P. constructor
Binomial name
	Polyrhachis constructor; Smith, F., 1857
Synonyms
	Polyrhachis elii Emery, 1900; Polyrhachis piliventris Smith, F., 1858;

In Thailand, carton nests of P. constructor were found on the underside of plant leaves or between leaves. They were located c.a. 1.59–2.80 m above ground on shrubs. The nest was around 1.74–10.53 cm long, 1.51–5.66 cm wide, and 0.22–0.95 cm deep, with only one nest entrance (Jaitrong et al., 2023).

Photo Gallery

Polyrhachis constructor. A–C, Non-type worker (NN220308-01); D–F, non-type alate queen (NN220308-02); A, D, body in profile view; B, E, body in dorsal view; C, F, head in full-face view. (Jaitrong et al., 2023, Fig. 1)
Polyrhachis constructor. A–C, Syntype of Polyrhachis constructor (alate queen ANTWEB CASENT0901846); D–F, syntype of Polyrhachis piliventris (alate queen); A, D (ANTWEB CASENT0903307), body in profile view; B, E (ANTWEB CASENT0903307), body in dorsal view; C, F, head in full-face view. (Jaitrong et al., 2023, Fig. 2)
Syntype of Polyrhachis elii (worker, ANTWEB CASENT0905566); A, Body in profile view; B, head in full-face view; C, body in dorsal view. (Jaitrong et al., 2023, Fig. 3)

Identification

Polyrhachis constructor is most similar to Polyrhachis longipilosa in having hairs on dorsa of head, mesosoma and gaster and on antennal scape. However, P. constructor has the shorter hairs and weaker sculpturing than in the latter (see figures 1 A–C and 6 for comparison) (Jaitrong et al., 2023).

Keys including this Species

Key to Polyrhachis flavicornis-group species from Thailand

Distribution

Polyrhachis constructor is distinctly allopatric with Polyrhachis longipilosa in distribution, occurring in Sundaland (southern Thailand and Borneo) and southernmost part of Indochina subregions (Prachuap Khirikhan Province). On the other hand, P. longipilosa is recorded from western part of Thailand (Kanchanaburi Province) (Jaitrong et al., 2023).

Latitudinal Distribution Pattern

Latitudinal Range: 13.1° to -2.183333°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: Jaitrong et al., 2023

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo (type locality), Indonesia (type locality), Malaysia, Singapore (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

Castes

Images from AntWeb


Holotype of Polyrhachis constructor. Queen (alate/dealate). Specimen code casent0901846. Photographer Ryan Perry, uploaded by California Academy of Sciences.	Owned by OUM, Oxford, UK.


Holotype of Polyrhachis piliventris. Queen (alate/dealate). Specimen code casent0903307. Photographer Z. Lieberman, uploaded by California Academy of Sciences.	Owned by NHMUK, London, UK.


Syntype of Polyrhachis elii. Worker. Specimen code casent0905566. Photographer Z. Lieberman, uploaded by California Academy of Sciences.	Owned by MSNG, Genoa, Italy.

Nomenclature

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

constructor. Polyrhachis constructor Smith, F. 1857a: 60 (q.) BORNEO. Combination in P. (Myrmatopa): Donisthorpe, 1932c: 445. Unplaced to subgenus: Dorow, 1995: 65, but Donisthorpe probably correct. [P. constructrix: Schulz, 1906: 156; unjustified emendation.]
elii. Polyrhachis elii Emery, 1900d: 711 (w.) INDONESIA (Mentawei I.).
- Combination in P. (Myrmatopa): Emery, 1925b: 180.
- Junior synonym of constructor: Jaitrong et al., 2023: 448.
piliventris. Polyrhachis piliventris Smith, F. 1858b: 60, pl. 4, fig. 24 (q.) SINGAPORE.
- Combination in P. (Myrmatopa): Dorow, 1995: 44; Bolton, 1995b: 354.
- Junior synonym of constructor: Jaitrong et al., 2023: 448.

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

Taxonomic Notes

Jaitrong, Yamane, and Noon-Anant (2023) - The syntype alate queen of P. constructor is quite similar to the syntype alate queen of Polyrhachis piliventris. Only minor differential characteristics or just variation have been seen: 1) head is slightly longer (CI 73 in P. constructor; CI 85 in P. piliventris); 2) posterior margin of head stronger convex than in P. piliventris; 3) anterior margin of mesoscutum weaker convex than in P. piliventris. The syntype workers of Polyrhachis elii are most similar to workers of P. constructor in most aspects but the body size is slightly larger and slightly denser hairs. However, we did not find any major characteristics to distinguish P. constructor (Figs. 1 A–C, 2 A–C) from the syntypes of P. piliventris (Fig. 2 D–F) and P. elii (Fig. 3 A–C). Thus, we here synonymize P. piliventris and P. elii with P. constructor.

Description

Worker

Jaitrong, Yamane, and Noon-Anant (2023) - (17 non-types). TL 7.25–7.55, HL 1.33–1.87, HW 1.03–1.57, SL 1.83–2.77, PW 0.83–1.33, MTL 1.90–2.67, CI 74–86, SI 171–184. Syntype (Polyrhachis elii). TL 7.25–7.30, HL 1.77–1.90, HW 1.47–1.50, SL 2.57–2.60, PW 1.03–1.27, MTL 2.47–2.67 CI 78–83, SI 173–175.

Head in full-face view distinctly longer than broad with posterior margin roundly convex. Clypeus in dorsal view, broad and weakly convex median portion, its anterior margin broadly convex; median portion of anterior margin produced with a pair of short lateral teeth, and margin between teeth almost straight. Frontal carinae in lateral view well elevated, in full-face view weakly sinuate, and reaching level of mid-length of eye. Mandible subtriangular, its masticatory margin with five distinct teeth (including basal and apical teeth). Antennal scape long, clavate, ca. 1.6 times as long as head width including eyes. Eye in full-face view convex, distinctly protruding from the lateral outline of head and located just posterior to mid-length of head laterally.

Pronotum in dorsal view broader than long, with convex lateral margins, humerus armed with short but sharp tooth; anterior margin of pronotal disc weakly convex and posterior margin concave; lateral face of pronotum subtriangular. Mesonotum in dorsal view subtrapezoidal, slightly broader than long, distinctly narrowed posteriad, shorter and narrower than pronotum; mesopleuron rectangular in profile shorter than high, with posteroventral corner roundly lobate. Propodeum in dorsal view rectangular, broader than long, not demarcated from posterior declivity by transverse carina; propodeal spines blunt, short, and pointed upward.

Petiolar node (excluding spines) in dorsal view without distinct dorsum; in profile view almost as long as high, tapered apically with posterior slope much longer than anterior slope; petiolar spines in dorsal view divergent, in lateral view slightly curved backwards, as long as the height of petiole; subpetiolar process weakly developed, posteriorly angulate or with small denticle.

Mandible densely and very minutely puncto-striate but weakly shiny. Vertex and frons of head densely macropunctate; clypeus, antenna, and legs micropunctate; lateral faces of mesosoma and petiole densely macropunctate; petiolar spines micropunctate; pronotum longitudinally weakly striate; mesonotum and dorsum of propodeum macropunctate. Gastral tergites densely superficially punctate and shiny.

Dorsa of head and mesosoma with dense, short standing hairs. Median point of anterior clypeal margin with a long hair. Antennal scape with dense standing hairs (most of them shorter than the maximum width of antennal scape); antennal segments II–XII with short standing hairs. Petiole with sparse appressed hairs; petiolar spines without hairs; sternite with sparse standing hairs. Gaster with dense pubescence mixed with sparse short hairs that are shorter than those on head. Legs with sparse short hairs. Body entirely black; legs reddish brown. Gaster in some specimens from colonies WJT04-S31 and KK14-Pol-06 reddish brown.

Queen

Jaitrong, Yamane, and Noon-Anant (2023) - (2 syntypes, 6 non-types). TL 8.85–9.15, HL 1.90–2.20, HW 1.53–1.70, SL 2.80–3.07, PW 1.73–1.87, MTL 2.67–3.13, CI 75–77, SI 175–191.

Similar to the worker in structure, sculpture, pilosity, and coloration, with the following conditions that should be noted: body slightly larger; head in full-face view oval, clearly longer than broad with posterior margin roundly convex; eye large, located close to posterolateral corner of head; median ocellus located at level of posterior margin of eye and slightly larger than lateral ocellus; in dorsal view, pronotum short, its anterior margin distinctly convex and posterior margin distinctly concave; mesoscutum trapezoidal; parapsidal line distinct and long; scutellum trapezoidal, almost as long as broad; metanotum short; metanotopropodeal sulcus deep; propodeum in profile view with almost straight dorsal outline; propodeal junction bluntly angular; petiolar spine short comparing with petiolar node; body hairs relatively denser and longer than in the worker.

Type Material

Type material examined by Jaitrong et al. (2023):

The syntype alate queen of Polyrhachis constructor from East Malaysia, Borneo, Sarawak (A.R. Wallace), deposited in OXUM.
Two syntype workers of Polyrhachis elii from Indonesia, Mentawai Island, Sipora, Sereinu, V–VI.1894 (E. Modigliani), deposited in MCSN.
The syntype alate queen of Polyrhachis piliventris from Singapore (A.R. Wallace), deposited in BMNH.

The following notes on F. Smith type specimens have been provided by Barry Bolton (details):

Holotype alate queen in Oxford University Museum of Natural History. Labelled “SAR.” (= Sarawak) and with a Donisthorpe type-label.

References

Donisthorpe, H. 1932c. On the identity of Smith's types of Formicidae (Hymenoptera) collected by Alfred Russell Wallace in the Malay Archipelago, with descriptions of two new species. Ann. Mag. Nat. Hist. 10(10): 441-476 (page 445, Combination in P. (Myrmatopa))
Dorow, W. H. O. 1995. Revision of the ant genus Polyrhachis Smith, 1857 (Hymenoptera: Formicidae: Formicinae) on subgenus level with keys, checklist of species and bibliography. Cour. Forschungsinst. Senckenb. 185: 1-113 (page 65, Unplaced to subgenus)
Jaitrong, W., Yamane, S., Noon-Anant, N. 2023. The Thai species of the Polyrhachis (Myrmatopa) flavicornis Smith, 1857 species group, with description of a new species (Hymenoptera, Formicidae, Formicinae). Zootaxa 5249(4), 446–464 (doi:10.11646/zootaxa.5249.4.3).
Smith, F. 1857a. Catalogue of the hymenopterous insects collected at Sarawak, Borneo; Mount Ophir, Malacca; and at Singapore, by A. R. Wallace. [part]. J. Proc. Linn. Soc. Lond. Zool. 2: 42-88 (page 60, queen described)

References based on Global Ant Biodiversity Informatics

Chapman, J. W., and Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327
Emery, C. "Formiche raccolte da Elio Modigliani in Sumatra, Engano e Mentawei." Annali del Museo Civico di Storia Naturale Giacomo Doria (Genova) (2) 20, no. 40 (1900): 661-722.
Kohout R.J., and M. Mohamed. 2008. A preliminary list of the Polyrhachis ants of the Maliau Basin Conservation area in Sabah, Borneo (Hymenoptera: Formicidae: Formicinae). Asian Myrmecology 2: 63-70.
Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58
Robson Simon Database Polyrhachis -05 Sept 2014