Contents Contents The Ants of Egypt
SUBFAMILY MYRMICINAE - Genus Monomorium Mayr

Genus Monomorium Mayr (1855: 452), includes previous Syllophopsis


Diagnostic Features - Antennae 11- or 12-segmented, with a 3-segmented club. Median portion of clypeus with two distinct longitudinal carinae; clypeus may also be concave between the carinae on the anterior margin, the carinae then project as a pair of blunt teeth. Eyes present. Promesonotal suture absent, metanotal groove impressed. Propodeum unarmed. Petiole pedunculate, node high and rounded. Postpetiole node less voluminous than petiole node in profile and narrowly attached to the gaster.

Mayr (1861: 71) reiterated his earlier (1855) genus description, this is at {original description}.

Emery (1915i: 190) listed what then were regarded as valid subgenera - and defined the subgenus Parholcomyrmex, type species Monomorium gracillima (as Myrmica gracillima, now a junior synonym of Monomorium destructor) - see {original description}. The main characteristics Emery listed were - slightly dimorphic workers; funiculus with a three-segmented club (Monomorium santschii with four segmented-club, type location Tunisia), the first two segments equi-sized.Emery (1922e) later synonymised Mitara with the older name Lampromyrmex, itself now regarded as a synonym of Monomorium.

The subgenus Holcomyrmex was defined by Mayr (1879: 671) , type species Monomorium scabriceps (as Holcomyrmex scabriceps, type location India) - see Emery's key (1915i: 190) - Card 2. The main characteristics Emery listed were - antennal club much shorter than rest of funiculus, often indistinct; workers pronouncedly dimorphic.

The Genus Syllophopsis was defined by Santschi (1915c: 259) and further tackled by Santschi (1921c: 119) - see {original description} and {original description}. Ettershank (1966) kept Syllophopsis separate from Monomorium but noted that he had not examined any specimens of Syllophopsis. Bolton (1987), however, synonymised Syllophopsis with Monomorium and he chose to set aside the concept of subgenera, instead using a format of species-groups, with a subordinate level of species-complexes. As a point of correction, Bolton (1987: 296) commented upon the subgenus Parholcomyrmex, as defined by Emery (1915i); writing that the name was - "also misspelled as Paraholcomyrmex later in the same publication". As the original text shows, it is obvious that Emery intended the name to be Paraholcomyrmex, literally (para-) similar to Holcomyrmex, as the name is printed in bold in the key, with the comment (translated) = male as Holcomyrmex.

The full original text of Bolton's revisionary study can be found at -
Bolton, B. 1987. A review of the Solenopsis genus-group and revision of Afrotropical Monomorium Mayr (Hymenoptera: Formicidae). Bull. Brit. Mus. (Nat. Hist.) Entomol. 54: 263-452. download entire file (16.6M)

André (1883a: 330) gave a key to the species then known from Europe and North Africa this is at {original description}. Monomorium gracillimum F Smith = Monomorium destructor (Bolton, 1987: 324). Santschi (1936a) attempted to sort out members of the subgenus Xeromyrmex Emery (1915), these essentially are members of the "salomonis-group" defined by Bolton (1987: 329). Unfortunately, although Bolton stated he had examined 15 extralimital species, in addition to the Afrotropical species dealt with in the paper, he has not gone on to publish modern descriptions of the extralimital species. Menozzi's (1933b) key to Monomorium from Palestine is at {original description}.

Thus, from Bolton (1987) the known Egyptian species fall into the species-groups as follows, except following the genus redefinitions in Ward et al. (2014: 10) the Trichomyrmex from Egypt are - abyssinicus, plus "destructor-group" members,  destructor and mayri.

fossulatum-group former Syllophopsis - with much reduced eyes, usually down to a single ommatidium, very narrow posteromedian portion of the clypeus, and a large strongly differentiated antennal club dentatum
scabriceps-group former Holcomyrmex - mandibles unsculptured; propodeal spiracle a short, near vertical, slit; polymorphic Trichomyrmex abyssinicus
destructor-group Propodeum rounded; mandibles sculptured; eyes small but distinct (0.13-0.20 X HW); propodeum dorsum transversely striate to costulate, even if only faintly Trichomyrmex destructor and Trichomyrmex mayri
monomorium-group Mandibles unsculptured; antennae 11-segmented (for Egypt/North Africa); propodeum dorsum smooth or if sculptured not with transverse striations; standing hairs at pronotal humeri atomum, carbonarium (note specimen photographed by Sharat is clavicorne), clavicorne, and mictilis; given for comparison exiguum and monomorium
salomonis-group Usually with distinct cephalic sculpture; eye moderate, oval or circular not reniform; scapes usually ca SI > 90; metanotal groove no more than weakly impressed -
areniphilum-complex {short description of image} Cephalic sculpture overlain by very fine dense scratch-like longitudinal striation, large eyes, characteristic altrunk outline; first gastral tergite with no more than a single pair of erect hairs forward of apical row areniphilum and related forms in North Africa; we include abeillei, lepineyi and pullulum, both new status species
australe-complex Small to minute species, with fine sculpturation giving silky appearance [Curiously there are no illustrations in the literature - despite the proliferation of species by Bolton, 1987] carbo
bicolor-complex Orange-yellow to red, gaster dark brown to black often with steely or bluish reflections, quite small eyes; sharply defined dense sculpture, with individual punctures small but very sharply defined; always with erect hairs present on first gastral tergite in front of apical row; erect hairs absent on alitrunk dorsum bicolor, jizane & nitidiventre [Bolton states this sibling-species of bicolor replaces it in part around the eastern end of the Mediterranean]
pharaonis-complex Cephalic dorsum and alitrunk everywhere blanketed by fine and very dense reticulate-punctulate sculpture; relatively small eyes (0.18-.0.21 X HW) set slightly in front of the midlength of the head; SI 105; metanotal groove distinctly impressed; pair of erect hairs on pronotal humeri and on mesonotum; first gastral tergite with standing hairs distributed evenly over the sclerite pharaonis
subopacum-complex With reduced but clearly visible cephalic sculpture and stronger sculpture on alitrunk; first gastral tergite with one or more pairs of erect hairs forward of apical row subopacum; presumably also salomonis and venustum
others Not separated in Bolton, 1987 - scape clearly surpassing the occiput, with relatively long slender funiculi; propodeal spiracle distinctly ovoid and anteriorly raised so that opening facing slightly rearward; propodeum with distinctive flat wedge-shaped dorsum niloticum
? chobauti-group (our designation)
not mentioned in Bolton, 1987; possibly in former subgenus Equestrimessor Santschi (1919a), as transporting grass seeds in a psammophore on the underside of the head; Ward et al. (2015) placed these in Trichomyrmex
bodenheimeri and, for comparison, barbatulum and chobauti
- not mentioned in Bolton, 1987 phoenicium

Provisional key to workers (* = not presently known from Egypt)

1 {Monomorium clavicorne antenna}Antennae 11-segmented 2
-- {Monomorium subopacum antenna}Antennae 12-segmented 5
2 Monomorium exiguumTL 1.5-1.7 mm; yellow, head and gaster more brown; cuticle of head translucent; lateral mesonotum and propodeum very finely rugoreticulate; erect hairs moderately long but relatively sparse; pronotum dorsum anteriorly with two pairs of long erect hairs. Pan-African (not definite from Egypt) - exiguum
-- TL < 1.5 mm; wholly smooth, very shiny; no sculpturation on lateral mesonotum and propodeum 3
3 Monomorium atomumTL 1.2-1.3 mm; apical segment of club as long as previous 8 segments together, those segments much wider than long; head an elongated rectangle; metanotal groove deep so that alitrunk forms two convexities; petiole with short peduncle, subconical, postpetiole more rounded, both segments small; few erect hairs; wholly smooth and shiny; wholly yellow with slight reddish tint, legs paler Middle East, inc Egypt, to Indian subcontinent -
-- Metanotal groove shallow with alitrunk profile not separated into two convexities 4
4 Monomorium clavicorneTL 1.4 mm; second segment of funiculus slightly longer than wide, large 3-segmented club, with apical segment twice as long as previous two together; pilosity very sparse on alitrunk, abundant on appendages and fairly so on gaster, whitish; no pubescence; smooth, very shiny; clear testaceous yellow, gaster apex sometimes slightly darkened Israel, Egypt & Tunisia - clavicorne
-- {Monomorium mictilis}TL 1.2-1.3 mm; yellow, apex of gaster darker; pronotum dorsum anteriorly with a single pair of long erect hairs; head with a noticeably depressed profile (at least upper if not lower surface) eastern & southern Africa, Egypt - mictilis
- Antennae 12-segmented .
5 Monomorium abyssinicum major workerPropodeal spiracle vertically slit-shaped or elliptical; anterior clypeal margin with a pair of prominent teeth overhanging the mandibles, heavy mandibles, polymorphic (TL 2.6-6.7), granivorous savannah species Pan-Sahel species
Trichomyrmex abyssinicus
-- Propodeal spiracle circular or nearly so; no prominent teeth on anterior clypeal margin 6
6 Head in profile flat or shallowly convex and with long hairs on clypeal margin and underside of head 7
-- Head in profile at least slightly convex ventrally, without numerous hairs on the underside 8
7 {Monomorium bodenheimeri}Eye flat and larger, elongated oval; scape not reaching occiput, underside of head slightly convex; psammophore relatively weak; in dorsal view postpetiole a weak small oval; first gastral tergite without erect hairs except on posterior margin Egypt -
Trichomyrmex bodenheimeri
-- Monmorium barbatulumTL 2.5-3.0 mm; underside of head flat; head unsculptured or finely granulous, except antennal fossae and genae which are striated, with with striations on the clypeus; alitrunk subopaque, except disc of pronotum which is smooth and shiny; petiole nodes near shiny; gaster smooth and very shiny; pilosity and pubescence sparse, very long hairs on clypeus and underside of head; pitch black, funiculus and legs brownish, apex of mandibles and tarsi testaceous * Turkestan - probably also in Trichomyrmex - barbatulum
-- {Monomorium chobauti}Eye smaller; scape not reaching occiput, underside of head slightly concave; psammophore well developed; in dorsal view postpetiole a square; first gastral tergite without numerous semi-decimbent hairs Algeria -
Trichomyrmex chobauti
- Head without psammophore hairs .
8 {Trichomyrmex destructor}Head shiny, smooth or lightly striated anteriorly and on the sides, sparse piligerous punctuation 9
-- {Monomorium bicolor}Head, other than part of clypeus, entirely and variably finely granulose, variably slightly shiny to matt 14
- Head almost entirely shiny .
9 {Monomorium nsp}TL ca 3.8 mm; eyes large occupying about one-third of side of head and distinctly sunken into sides of head; scapes surpass the occiput; distinctly bicoloured, all except gaster yellowish-brown, gaster brownish-black, darkest apically
-- Eyes small to minute, occupying 0.25-0.20 of sides of head or minute of a single ommatidium 10
10 {Monomorium_dentatum}Eyes of a single ommatidium; propodeum with distinct denticles Egypt - dentatum n sp Sharaf
-- {Trichomyrmex destructor lateral head}Eyes small, occupying 0.25-0.20 of sides of head; whole of body smooth and almost so, other than several transverse rugae on the propodeum 11
11 Pedicel slender and elongated 12
-- Pedicel slightly elongated, petiole with a short peduncle, postpetiole wider than long 13
12 {Monomorium destructor}TL 2.2-3.0 mm; postpetiole longer than wide; pilosity sparse, pubescence almost nil; colour variable testaceous yellow to red-brown, with gaster brown-black, with dark varieties appendages tend to be brighter North Africa through Middle East to India and tramp
[gracillimum F Smith] Trichomyrmex destructor
-- {short description of image} Generally dark brown, with more pronounced transverse sculpturation on the propodeum; erect hairs relatively abundant, especially on the alitrunk dorsum  Trichomyrmex mayri
13 {Monomorium monomorium}TL 1.5-2.0 mm; pedicel of petiole relatively short; pilosity very sparse, pubescence almost nil; black or brown black, appendages reddish yellow * southern Europe, North Africa, Syria, Madeira & North America
[minutum Mayr] monomorium
-- {Monomorium carbonarium}TL a little more than 2 mm; clypeus with short deep longitudinal notch limited laterally by carinae which terminate in a raised tooth; even darker to wholly black North Africa, Yemen (Aden), Madeira, America
. Head almost entirely granulose-reticulate, no more than slightly shiny if not matt .
14 {Monomorium pharaonis}TL 1.75-2.3 mm; funiculus with first segment as long as next three combined; pilosity very sparse, pubescence almost nil; body overall finely granulose-reticulate, matt, except median area of clypeus and gaster which are smooth and shiny; entirely yellow sometimes slightly reddish, with gaster variably blackish apically Pan-global tramp
-- {Monomorium bicolor antenna}Funiculus with first segment about the same length as next two segments combined 15
15 {Monomorium bicolor}Head elongated, CI ca 75 or less, with occiput noticeably impressed (best seen from above head rather than full-face view) 16
-- {Monomorium salomonis face}Head only slightly elongated, CI 80 plus, oval with sides rounded; occiput not or only slightly impressed and slightly widest anteriorly 18
16 Monomorium carboTL 1.6-1.7 mm (Forel) [Bolton (1987) has TL 2.3-2.4 mm]; scape reaching the occiput; head pronouncedly rectangular, CI 71-72; metanotal groove very shallow; no propodeal longitudinal groove; head and alitrunk brown or darker, gaster black Eritrea and ? Egypt
-- Bicoloured with head and alitrunk distinctly lighter, red or reddish-brown, than dark brown to black gaster 17
17 {Monomorium bicolor}TL 2.5-3.5 mm; head with sides almost straight and parallel; little pilosity and fine sparse pubescence; propodeal spiracle minute and circular; petiole in dorsal view quite narrow; head, alitrunk and petiole densely but quite finely granular; gaster superficially shagreened, shinier ventrally; entirely light red with gaster black-brown, often with basal reddish area Egypt and sub-saharan Africa, north of the Equator
-- {Monomorium nitidiventre}TL 2.5-2.8 mm CI 78; head rather shorter and scapes not or barely reaching occiput; head with more numerous psammophore type hairs on underside; also head and alitrunk shiny; gaster also shiny with a bluish sheen Egypt, Cyprus & Middle East -
-- Monomorium jizaneTL 2.5 mm, CI 72-76; erect hairs on head restricted, a projecting hair near each corner of occiput; petiole profile a low triangle
Egypt and Saudi Arabia -
. Head only slightly elongated, CI 80 plus, oval with sides rounded; occiput not or only slightly impressed and slightly widest anteriorly .
18 {Monomorium abeillei propodeum}Propodeum dorsum with deep longitudinal groove or furrow; alitrunk profile flat with shallow metanotal groove; petiole node with a high, round-topped profile 19
-- Propodeum with no or only very slight longitudinal grooving; head, alitrunk and pedicel clear red or red-brown; distinctive shiny clypeus 20
19  Monomorium abeilleiTL 3.0-3.5 mm; postpetiole ovoid in dorsal view, wider than long; body finely shagreened, matt or slightly shiny, gaster smooth and shiny; head alitrunk and petiole dark brown black, occasionally reddish, gaster dark red-black, appendages brown, mandibles yellow-brown contrasting with rest of head Israel and Egypt
-- {short description of image}TL ca 3.0 mm?; base of gaster matt; sculpturation on front of head relatively coarse and aligned so as to appear striate; head & alitrunk dull yellow-red, gaster dark; alitrunk profile similar to subopacum (below) North Africa & Middle East
20 {Monomorium venustum}Clypeus shiny with deep median longitudinal groove bordered by carinae which terminate in a small tooth; TL 3.0-4.0 mm; with deep metanotal groove; head finely granulose, near shining, alitrunk and pedicel finely shagreened, gaster smooth and shiny; overall clear ferruginous, gaster brown black * Syria & Ethiopia (?)
-- Clypeus with no more than shallow longitudinal groove; generally smaller; head, alitrunk and pedicel more or less dull; red-brown or darker 21
21 {Monomorium subopacum}TL 2.5-3.0 mm; alitrunk with weak metanotal groove; post-petiole near circular in dorsal view; whole of head and alitrunk matt, gaster dull to shiny matt; colour as salomonis but usually redder; longish hairs on underside of head; first tergite of gaster with a single pair of erect hairs forward of row on posterior border; distinct anterior lateral angles on gaster Circum-Mediterranean and into Syria and Saudi Arabia
-- {Monomorium salomonis} TL 2.5-3.5 mm; alitrunk with deep metanotal groove 22
22 Monomorium salomonis TL 2.5-3.5 mm; alitrunk with moderately deep metanotal groove; propodeum with narrow longitudinal groove and margination; in profile petiole with apex sharp; postpetiole near circular in dorsal view and no wider than petiole; head slightly shiny, gaster quite shiny; variably dark chestnut brown, with head and gaster often darker North Africa and east to the Indian subcontinent
-- Propodeum without a longitudinal groove or margination; cephalic sculpture overlain by very fine dense scratch-like longitudinal striation, large eyes, metanotal groove pronounced; higher petiole node with a relatively narrow profile 23
23 {Monomorium lepineyi}TL ca 3 mm; HL > HW; alitrunk and gaster slender; head with fine indistinct sculpturation; eye more elongated; propodeum profile more rounded; overall very dark brown to black, with reddish areas, specially the mandibles Sahel
-- HL = HW; generally red-brown not very dark and shiny 24
24 {Monomorium pullulum}TL 3.7 mm plus; head with fairly coarse but somewhat indistinct sculpturation; eye more nearly circular (wider in vertical plane) than others; propodeum profile angular in effect giving three faces; alitrunk more red-brown North Africa & Sahel
-- {Monomorium areniphilum}TL 3.1-4.3 mm; cephalic sculpture finer; first gastral tergite with no more than a single pair of erect hairs forward of apical row; generally dark brown but with variable lighter areas North African Sahel zone
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