Polyrhachis lacteipennis F Smith

Type location India (Polyrhachis lacteipennis F Smith, 1858b: 60, illustrated, queen) Northern India - see below
junior synonym simplex (Polyrhachis simplex n. sp., Mayr, 1862: 682, queen) Kashmir - no images on Antweb (July 2014)
and its junior synonyms
obsoleta (Polyrhachis simples var. obsoleta n. var., Forel, 1893c: 26, in key, worker) India, Poona, R Wroughton - see http://www.antweb.org/specimenImages.do?code=casent0910897
spiniger (Polyrhachis spiniger n. sp., Mayr, 1879: 653, worker & male, synonymy Forel, 1893c: 36) "Ostindien", Rothney (India)  - no images on Antweb (July 2014)
ssp grisescens (Emery, 1895k: 483, worker & queen, synonymy Bolton, 1974b: 177) from Myanmar [noted only that pubescence much less sparse giving a grey reflection to the gaster] - see bottom of this page.

F Smith's (1858b) description is at . Mayr's (1862) description of simplex is at . Mayr's (1879: 653) description of spiniger is at . Forel's (1893c) description is at .

The photomontage of the type queen is collated from http://www.antweb.org/specimen.do?name=casent0903386

Note - although F Smith (1858b) stated the petiole (of a queen) as having the centre of the margin emarginate, his drawing Fig 40 shows the petiole with a pair of short median spines or teeth! Bingham's (1903) illustration of the worker clearly shows the petiole as described by Smith, i.e. emarginate medially.

Bingham (1903: 383ff) gave a key to Polyrhachis from the Indian subcontinent - simplex keys as - alitrunk and petiole armed with spines or teeth ... pronotum and propodeum with a spine on each side (mesonotum unarmed) ... propodeum not laterally margined ... propodeal spines not hooked ...pubescence sparse ... petiole spines not very wide-spreading (not encircling gaster) ... generally black ... head, alitrunk and petiole finely punctate ... node of petiole without median spines ... simplex (p 394). Bingham does not mention lacteipennis in his very comprehensive text, even though it appears to be one of the commonest members of the genus in southern Asia.

The specimens sent to BT from Israel and shown below would appear to differ significantly from the (poor) descriptions of lacteipennis from the Indian sub-continent and a fuller analysis could lead to a separation of the Egypt-Middle East specimens into a distinct species [BT opinion].

Two further workers from Iran (below) match the Israel specimens.  While looking for Antweb images, I came across (October 2015) the paper by Dietrich (2004). In that he felt it justified to designate the Middle East from as a new species, Polyrhachis palaearctica. Antweb do not have images of the type but the SEM images of the lateral and dorsal alitrunk are a close fit to those I have. Two factors appear to cast slight doubt on Dietrich' s findings.  First he mentions P. lacteipennis only vaguely. He did not list it as a species and did not sight the type queen or, apparently, the type of what he refers to as "Polyrhachis simplex".  The latter he placed as a junior synonym of Polyrhachis spiniger. He separated Polyrhachis grisescens as a separate species but the type images (bottom) are little or not different from the fresh specimens from Israel and Iran. Dietrich refers to a paper on the ant in Israel by Ofer (1970) but in that the species was given as P. simplex. So, pro tem, I leave the findings as under Polyrhachis lacteipennis.

DIETRICH, C.O. (2004) Taxonomische Beiträge zur Myrmekofauna Jordaniens (Hymenoptera: Formicidae). Denisia 14, zugleich Kataloge der OÖ. Landesmuseen Neue Serie 2 (2004), 319-344.

OFER, J. (1970) Polyrhachis simplex the weaver ant of Israel. Insectes Sociaux, 17, 49-82.

Egypt records - Wheeler & Mann (1916) reported it as junior synonym simplex; as spiniger from Wadi Feran, Sinai Peninsula, nesting on trees and tending Membracids. Emery (1925b), however, drew attention to Forel (1909e: 402 & 404) where simplex was stated to make a silk-lined nest in a subterranean cavity. Attributing the discovery to Wroughton, Forel (p 404) had: Nest of a single compartment (uniloculaire) with fine, pure, silky tissue, lining a subterranean cavity. Dietrich (see above) appears to have found reports of Israel populations with nests in the ground or uncommonly low down on tree trunks.

Menozzi (1929e: 128) reported two queens from Wadi Scheich and diverse workers from Wadi Feiran, collected in Sinai by F S Bodenheimer. Also by Finzi (1936) from Wadi Feran, 4.iii.1935.

Mohamad thesis (1979) had - "Polyrhachis viscosa" - Gebel Elba, 16-26.i.1933 (Coll. Min.) - this probably was an error for P. lacteipennis, as there is a superficial similarity, although Polyrhachis viscosa is easily separated by the alitrunk dorsum having sharp lateral margination.

The apparent discontinuity in geographical distribution appears to be bridged by the reports in Collingwood (1985: 274, as simplex) and Collingwood & Agosti (1996: 375) of findings in Oman, Yemen and Saudi Arabia. These authors also refer to median petiole spines as being absent or reduced to tubercles. In neither paper, however, is there any description of the specimens.

By extracting from Forel's (1893c) key (as simplex) one gets the following description (from the progressive key couplets) -
Eyes rounded; alitrunk not bordered, or with solely the propodeum bordered; scupture accentuated, matt or subopaque, alitrunx spined; mesonotum unarmed, petiole bispinose; body, at least in part, with distinct sculpture, matt or subopaque; pronotum with two spines; metanotal suture indistinct or not visible, often two teeth between the petiole spines; propodeum not bordered; petiole without hairs, the spines not recurved apically; propodeal spines not recurved (like the horns of a chamois) or weakly recurved upwards at their extremities, head without tubercles (laterally behind the eyes); head and alitrunk with large reticulations which are weak and more or less effaced [unlike those on armata], rest finely and densely reticulo-punctate and matt as on the gaster; pronotum strongly convex above; alitrunk spines quite short, specially those on the pronotum; propodeal spines divergent and curved outwards; petiole and gaster as in P. tubericeps but the spines and specially the dorsal teeth much shorter; black, matt; pubescence very short and extremely sparse; almost no erect hairs; TL 4.8-5.8 mm.

Alitrunk of Polyrhachis armata type form - showing the "gross and deep reticulo-puncturation" referred to in Forel's key. The photograph is derived from http://stri.discoverlife.org/mp/20q?search=Polyrhachis+armata&guide=Ants_Java. The species is known from South East Asia.

The photomontage is of a worker from Israel, Ein Gedi (Dead Sea Valley), 12.iv.1982, leg J Kugler identified by Prof J Kugler as lacteipennis, sent to BT by Armin Ionescu.

Taking the available information, which is surprisingly sparse for a reportedly common Indian species, these specimens appear to be quite distinct from lacteipennis.

Dorow (1995a: ) placed lacteipennis in the dives species-group, of Subgenus Myrmhopla Forel; . P. dives from Singapore is clothed with pale golden pubescence and all the others are from India south- and eastwards.

These have a weak but noticeable margination of the propodeum and seemingly much stronger sculpturation of the the head, alitrunk and petiole, i.e. more like armata. Structurally they are more like the members of Dorow's Polyrhachis crypteroceroides species group but those are all very small, TL 5 mm (these have a TL of 6.25 mm) and have marginate genae, plus a proximally transverse margin on the first gaster segment.

The photomontage is of worker from Iran, Fouzieh Heidary (15).

The photomontage of the Polyrhachis grisescens type minor worker is collated from http://www.antweb.org/specimenImages.do?name=casent0905639.