SUBFAMILY DORYLINAE - Subgenus Rhogmus
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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 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. |
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Separation of known major workers (note the earlier
separation on antennal segment count was misleading)
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Queens
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Key is developed from Santschi (1919b) |
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Genus Dorylus and Key |
© 2007, 2009, 2013, 2014 - Brian Taylor CBiol FSB FRES 11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K. |
href="rhogmus.htm"
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). 
TL
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
TL 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
The queen only is known for - Ivory Coast - 
Pygidium
deeply impressed (scalloped)
Pygidium scarcely or not scalloped
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; 
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 "
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
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
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 