Polyrhachis rastellata

The identity and distribution of this species has not been firmly established (see below) hence little can be inferred from any records about Polyrhachis rastellata biology.

Identification
Polyrhachis rastellata resembles Polyrhachis lepida. Polyrhachis lepida is generally smaller, with a distinctly more convex occiput and longer antennal scapes (SI 128-136 versus 111-123 in Polyrhachis rastellata). The petiolar spines differ, with the lateral pair in Polyrhachis lepida distinctly longer than the dorsal pair. In contrast, the petiolar spines in Polyrhachis rastellata are subequal or the lateral pair is somewhat shorter than the dorsal pair. The two species also differ in the colour of their legs with those of Polyrhachis lepida consistently darker. (Modified from Kohout 2006).

Distribution
In the literature, Polyrhachis rastellata has been reported to occur over most of south-east Asia and south across Indonesia and New Guinea to northern Australia. However, many of these records are linked to the numerous infraspecies connected to that name. Several authors, including Mayr (1872: 138) and Wheeler (1919: 136) listed Polyrhachis rastellata from Borneo and various authors have listed it from New Guinea. Consequently, I have included it in the lists and keys of species from both regions. However, I have not seen any Bornean or New Guinean material satisfactorily comparable with the specimens from India that Donisthorpe considered to be Polyrhachis rastellata and I believe that the nominal form is restricted to India, Sri Lanka, Myanmar and former Indochina, including Sumatra and possibly Java. (Kohout 2006)

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Papua New Guinea, Philippines. Oriental Region: India, Sri Lanka, Thailand. Palaearctic Region: China.

Nomenclature

 *  rastellata. Formica rastellata Latreille, 1802c: 130 (q.) INDONESIA ("Indes orientales"). Mayr, 1862: 688 (w.); Mayr, 1876: 70 (m.); Crozier, 1970: 115 (k.); Wheeler, G.C. & Wheeler, J. 1990b: 756 (l.). Combination in Polyrhachis: Smith, F. 1858b: 59; in P. (Cyrtomyrma): Forel, 1915b: 107. Senior synonym of ceylonensis Donisthorpe: Dorow, 1995: 24. See also: Kohout, 2006b: 114. Current subspecies: nominal plus congener.
 * ceylonensis. Polyrhachis (Cyrtomyrma) rastellata var. ceylonensis Donisthorpe, 1938c: 256 (w.) SRI LANKA. [Unresolved junior primary homonym of ceylonensis Emery, above.] Junior synonym of rastellata: Dorow, 1995: 24.

Type Material


The identity and range of Polyrhachis rastellata is somewhat muddled. Kohout (2006) explains: "During the past two centuries more than twenty infraspecific names have been connected to this name. My current interpretation of this species is based upon specimens from India that Donisthorpe considered to be Polyrhachis rastellata [‘Described from an Indian specimen (Wroughton)’ (Donisthorpe, 1938)]. However, the type locality of Polyrhachis rastellata is the ‘Indes orientales’ or the East Indies, and probably corresponds to modern day Malaysia and Indonesia. Consequently, interpreting Polyrhachis rastellata based on Indian material may well be incorrect. It would be highly desirable to establish the nomenclatural stability of this species by the designation of a neotype. However, I believe that such an action would not be appropriate here, as I have not attempted a revision of the Asian fauna of the subgenus."

From Kohout (2006): The holotype queen of Polyrhachis rastellata was apparently lost “a long time ago” (J. Casevitz Weulersse,, pers. comm.). The type locality, given as the East Indies ("Indes Orientales"), probably corresponds to modern Malaysia and Indonesia.

Additional 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.

Latreille, P.A. 1802. Histoire Naturelle des Fourmis, et recueil de mémoires et d’observations sur les abeilles, les araignées, les faucheurs, et autres insectes. Paris.