Dorylus (Anomma) ornatus (Santschi)
Type location Cameroon (Dorylus (Anomma) nigricans
st. burmeisteri var. ornata, in text by
Santschi, 1912b: 161); Bolton has this as "unavailable name"
.
Considered by Santschi (1912b, quoted in Raignier & van
Boven, 1955) as a form intermediate between rubellus and
rufescens, a somewhat odd statement (R & vB) but it
was held at the time that rufescens was a variety of burmeisteri.
Santschi briefly noted how - it recalls rufescens by its
shape and colour but the head is shiny in all individuals, as in
rubella. I take as the type of the variety ornata
some examples from Cameroun (communicated by Emery) with the
colour wine-red with a sharp black anterior border to the head.
Raignier & van Boven commented how the resolution of the
validity of forms based on colour variation needed more samples
than they had before them [the latter is held here as no more than
pale specimens of burmeisteri, see above]. Wheeler
(1922) has no locations other than the original description from "Cameroon".
The photomontages are of specimens from Tanzania and
Uganda. The former were from Mahale forest, collected by S.
Uehara, 5 March 2002; they match Santschi's colour description
very well. Specimens were collected also on 2 March 2002 and 8
March 2002 but only the 5 March specimens included the major
morph. See the
Website
for details of the research and location.
The number of specimens of all morphs, see the polymorphism
montage below, the consistency of the bright colour among all the
specimens, and the collection from three locations argue for this
as a valid species. In October 2003, Professor Uehara sent me
further samples with three sets of specimens from the Kalinzu
Forest, Uganda (30°07'E 0°17'S); all the sets
matching the characters I have described below. |
Polymorphism
- The various morphs are shown in detail on the
Dorylus (Anomma) ornatus
morphs page |
Full new description - Mahale
05-03-02 (dimensions, others without major morphs), Mahale
02-03-02 and Mahale 08-03-02
Overall - all over shiny to polished rich chestnut, darkest on
apical gaster and front of head; appendages golden chestnut
TL 9.9 HW 3.0 HL 3.0 HD 1.5 CI 100 SL 1.25 SI 42 AL 3.0 PW 1.25
PetL 0.65 GL 3.25 MFL 2.4
Head
- widest at about 1/4 length, narrowing to 2/3 at posterior; sides
smoothly convex; posterior margindeep near semicircular scallop,
posterior corners sharply rounded; sculpturation very highly
polished, almost totally effaced spiculation visible only in
oblique light; minutest of sparse hair pits; median line barely
visible, most noticeable as raised line in mid-occiput; clypeal
margin very slightly sinuous, with several long very fine hairs;
mandible long and slender, no subapical teeth or denticles, basal
tooth moderately sized equilateral triangle; scape relatively
narrow, broadening from base to apex, shiny, with sparse fine
pilosity; funiculus all segments not much longer than wide,
bristly; head profile with dorsum bulbous, with concave frontal
area; venter in two distinct planes, anterior shallowly convex,
posterior 1/3 flat and angled to posterolateral processes smaller
than in wilverthi; minute stout hairs from hair pits.
Alitrunk - short and highly domed distinct "saddle";
spiracle large circular and distinctly rearward facing; propodeum
smoothly curved front to back with no change in curve from dorsum
into declivity; metapleural gland upper flange hardly longer than
lower; overall shiny matte due to spiculation; minute sparse stout
hairs on shoulders.
Petiole - relatively short with all edges rounded; distinct
posteroventral process; in dorsal view posterior about 1/3 wider
than anterior; spiracle small but very distinctly raised; ventral
moderate angular process; sculpturation as alitrunk; hairs single
pair on dorsum, few ventrally.
Gaster - base as petiole, rest smooth and shiny ; hairs not many
dorsally, but the same distinct micro, stout pilosity as pronotum
and head.
Legs - coxae relatively long; femora relatively long broad and
shiny, micropilosity as elsewhere; tibiae relatively long and
broad apically, finely bristly; tarsi moderately thick, bristly,
exceptionally heavy claws, last segment very hairy.
|
Minima morph
Head colour dark red chestnut, with distinct margin to anterior
yellow brown; dorsum with fine decumbent incurved pilosity; scape
dark yellow brown, apex lighter; funiculus yellow-brown, short and
stout with segments dark edged. |
Arnold
(1952) commented on a queen and workers taken together at
Kinganop, Kenya, by Mrs V Fey. I have adapted his illustration
(right) (see also
.
Arnold titled his paper as a note on "a Female Dorylus
(Anomma) Nigricans Ill. taken with workers" and labelled the
illustration "Anomma nigricans var. molesta"
(now molestus), arguing that, according to the key
produced by Santschi (1912), because the posterior angles of the
petiole are prolonged backwards, they must be molestus. My
interpretation (2007) is that they are quadratus. Under
Dorylus
(Anomma) molestus, I show that species has a distinctive
narrow, parallel-sided petiole and does not have
posteroventral extensions on the petiole. Moreover, the head
shape of the major in Arnold's picture and the female match the
illustrations I use here; the latter being that of Raignier &
van Boven. Essentially, I feel the same way about the specimens
described by van Boven (1972) as molestum (molestus)
[see ],
which to me are not molestus but quadratus
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