The Ants of Africa
SUBFAMILY DORYLINAE - Subgenus Rhogmus
Genus Dorylus and Key

Subgenus Rhogmus Shuckard (1840c: 323)

Diagnostic Features - Antennae 11-jointed; worker major 8 mm long; subapical tooth of mandibles double or truncate; impressed area of pygidium without sharp margins.

Shuckard's (1840c) genus definition, based on the male of "Rhogmus fimbriatus", is at {original description}. Reduced to subgenus of Dorylus by Emery (1895j: 702).

My earlier key was misleading as Emery (1901c) and Arnold (1915) pointed out that the subgenus members (at least D. fimbriatus) have reducing antennal segment counts with decreasing worker size. For fimbriatus this is TL 7.5 mm, major worker, and TL 3.5 mm, antennae 11-segmented; TL 3.1-2.7 mm 10-segmented; 3.0-2.6 mm 9-segmented; 2.2-1.7 mm, 7-8-segmented.  The sole described workers of  fuscipennis and termitarius were generally smaller than the fimbriatus major.  Emery (1901c) separated the then known major workers as fimbriatus with 11-segmented antennae and fuscipennis with 10-segmented antennae.


Separation of known major workers (note the earlier separation on antennal segment count was misleading)

1 {short description of image}TL 7.16-2.12 mm; dark orange-brown. Head, alitrunk and petiole finely reticulostriate, striations more marked dorsally (no photos of major worker available).
Pan-African - fimbriatus
-- Major worker with 10-segmented antennae 2
2 Dorylus fuscipennisTL 6.9-3.8 mm; major mandibles strongly and densely puncturate; head densely but grossly and deeply puncturate; head and mandibles rust or brownish; thorax reddish; petiole, gaster and appendages yellow or slightly rust West Africa & Congo Basin - fuscipennis
-- Dorylus termitarius majorTL major 6.6 mm; head rectangular longer than wide, with shorter occipital notch; major mandibles narrow and smooth; head very densely and finely sculptured; reddish yellow-brown, head darker red
Congo Basin - termitarius

Queens

{Dorylus (R.) fimbriatus queen}The queen only is known for - Ivory Coast - ocellatus


Males

Key is developed from Santschi (1919b)

1 {Dorylus leo pygidium}Pygidium deeply impressed (scalloped) 2
-- {Dorylus fuscipennis male pygidium}Pygidium scarcely or not scalloped 5
2 {Dorylus leo male}Wings blackish; TL 28-32 mm, HW 4.8, PW 5.5-5.7; reddish-fawn, gaster brownish posterior to the border of the basal segment, with a brown patch around the stomata; head blackish; long red silky pilosity, slightly oblique on the alitrunk dorsum, on the posterior of the petiole, the apex of the gaster; dense golden pubescence on the front of the head, the gaster and pygidium; Ivory Coast - male only known - leo
-- Wings yellowish 3
3 Pygidium pubescent, except for a median line 4
-- {Dorylus laevipodex male}Pygidium shining with several clear hairs; alitrunk hairs sinuous, giving a woolly or shaggy appearance; occiput in full face view shallowly but distinctly convex; mandibles with sparse basal long hairs; gaster width to 7.3, anterior wing 23 mm - note separated by me before as "laevipodex" but that appears identical to the type fimbriatus and this differs from that.
Kenya - undetermined
4 {Dorylus fimbriatus}Alitrunk length 6 mm; TL 37 mm; head very hairy, also dorsum of alitrunk, apex of gaster and last two sternites; testaceous-red, head black on vertex and posteriorly; scape a quarter of the antenna length; wings sub-hyaline, nerves thick and brown; mandibles with abundant basal long hairs .
. {Dorylus fimbriatus} Pan-African - fimbriatus
-- Alitrunk length 5.2 mm; HW 4.4, PW 5-5.2, petiole width 3.3, gaster maximum width 6, wing 20; mandible more acuminate, external margin less distinctly concave; pygidium with weaker pubescence Congo - fimbriatus ssp crampeli
5 Apical third of mandibles wide, gaster cylindrical, underneath of hypopygium shiny, not velvety 6
-- Apical third of mandibles tapering, gaster club-shaped, underneath of hypopygium matt and velvety 7
6 {Dorylus savagei male}Mandibles large, stipes rounded; TL 28-33 mm; dark brownish-yellow, head brown, mandibles, antennae and legs red-brown; wings dark brown, veins black; body hairs reddish; pygidium glabrous .
. {Dorylus savagei male} West Africa & Congo Basin - male only known - savagei
-- Stipes more acuminate; TL 25 mm; body hairs more yellow Nigeria - savagei ssp mucronatus
7 {Dorylus fuscipennis male}Alitrunk clear red, gaster brownish; TL 28-30 mm, PW 5.3-6, gaster maximum width 7, wing 20-21; alitrunk hairs shorter and more decumbent; wings strongly smoky, with strong black nerves .
. {Dorylus fuscipennis male} West Africa & Congo Basin - fuscipennis
-- Colour otherwise 8
8 Entirely brown Ghana - fuscipennis ssp lugubris
-- clear red with gaster segments edged with brown Ivory Coast - fuscipennis ss marginiventris
Contents Genus Dorylus and Key
2007, 2009, 2013, 2014 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

href="rhogmus.htm"