Monomorium new species in barbatulum-group

WORKER - TL ca 3.8 mm, HL 0.78, HW 0.6, CI 74, SI 125. The photomontage below is of a specimen collected by Mike James from St Katherine Protectorate, Sinai. Other images can be seen in the folder at - .

Mike James noted that foraging is early morning and evening, taking food items back to nests under plants or rocks.

Initially I thought this was Monomorium niloticum Emery, but that was noted as coastal (riverine?), with HW 0.80-0.88 and SI 100. Fresh specimens from Egypt and Sudan are shown on the linked page and those match the original description.

The James specimens have a lower petiole profile, a shiny pronotum dorsum and a shallow median impression on the clypeus, all clearly distinct from niloticum.

From the key in Collingwood & Agosti (1996), starting with the terminal segment of the funiculus being longer than the preceding two together, one would get to Monomorium rimae; but that is much smaller with short antennal scapes, TL 1.8 mm, SL 0.25 (SI = HW/SL = 70.2) [see pdf page 38 (337)]. The Monomorium analysis and new species, etc., in Collingwood & Agosti was checked by Bolton, who had revised the Afrotropical Monomorium in 1987 but has not reviewed species from North Africa or the Middle East.

The photomontage is of specimens from Egypt, also St Katherine, collected 2010, by Amy Shepherd. Other images can be seen in the folder at - .

The photomontage is of further specimens from St Katherine, also collected 2010, by Amy Shepherd. Other images can be seen in the folder at - .

On reading Santschi' s analysis of Monomorium (1936a: 36), however, the description of Monomorium luteum Emery (Emery, 1881b: 533, holotype worker only), type location Aden, seemed very similar to these specimens.

Emery's (1881b) description is at . Santschi (1936a) gave a fuller illustrated description, apparently based on examination of the holotype by Menozzi; this is at . The size given by Emery is TL 3.4 mm, with a slender form, the petiole nodes are subequal with the first being higher.

My translation of Santschi is -
"Head rectangular, a quarter longer posteriorly than the width; with the head slightly narrower anteriorly; the occipital border straight, the sides weakly arcuate with the posterior angles rounded. Eyes set at the midpoint and about one quarter of the head length. Frontal carinae weakly arcuate, parallel about a quarter longer than the space between. Anterior border of the clypeus weakly impressed between the weakly divergent carinae. Mandibles striated. Scape surpassing the occiput by about a quarter of their own length. All funiculus segments longer than wide (Fig. 11). Promesonotum slightly convex dorsally, like that of zanoni (Fig 21) but with a wider metanotal groove. Profile of dorsum of propodeum flat, subbordered and with a longitudinal grrove continuing onto the declivity, that is short and with a 110° angle from the dorsum. Petiole profile as zanoni but with a longer pedicel. Postpetiole higher than long but not bigger than the petiole. Legs elongated. Pubescence of the appendages slightly oblique; scape with some erect hairs. Type TL 4.3 mm (?) from Ras Doumier Ah (G. Doria), 30.xii.1879". In his key, Santschi separated luteum as being entirely yellow - this seems to be the main difference from the specimens collected by James and Sharat. A possibility is that Emery saw only a freshly emerged specimen in which the colours had not darkened.

We (Mostafa Sharaf) now, 2010, have collected a specimen of Monomorium luteum. or at least a specimen much closer to the Santschi description, from Saudia Arabia.

Collingwood & Agosti (1996) report luteum but separate it in their key as "Larger species, TL at least 3.8, HW more than 0.75". In their text (p 349) they have TL 4.0-4.2, HL 1.13-1.15 [given as 113-115?] HW 0.76-0.78; SL 1.10-1.13; CI 66.1 SI 1.140-1.147. The petiole node is given as low with a smoothly rounded dorsum - quite different from the Emery or Santschi descriptions. Collingwood (1985: 271) says little but implies he had seen specimens in Berne and from Oman, with the body colour yellow except for the brown apex of the gaster; he does not list Santschi (1936a) among his references. Collingwood & Agosti list that paper but do not refer to the luteum description.