A new East African genus of spirostreptid millipedes (Diplopoda, Spirostreptida, Spirostreptidae), with notes on their fungal ectoparasite Rickia gigas
Author
Enghoff, Henrik
text
Zootaxa
2017
4273
4
501
530
journal article
32891
10.11646/zootaxa.4273.4.3
0935deaf-8f18-434e-b4a0-0468cefc9577
1175-5326
803704
4CD96097-1016-47CB-8DC3-AD6E9EDA330C
Tropostreptus austerus
(
Attems, 1950
)
comb. nov.
Figs 2
,
8
G, 10A, 14, 15A
Epistreptus austerus
Attems, 1950
: 217
Diagnosis.
A large species of
Tropostreptus
(
Fig. 2
). Differs from other species, except
T. severus
, by the combination of size and the presence of three apical lobes/processes on the gonopodal metaplica. Differs from
T. severus
by the smaller size of the lateral proplical lobe (
lpl
) and the basad(-laterad) curvature of the telopodital antetorsal process (
atp
).
Material studied
(total: 18 ♂♂, 10 ♀♀)
Holotype:
♂ “
Epistreptus austerus
Attems, 1950
, E-Afrika Umgebung v. Amani, leg. Bogert” (NMW 2430).
New
material:
All
from
TANZANIA
,
Tanga Region
,
East Usambara Mts
, all in
ZMUC
:
13 ♂♂
,
5 ♀♀
Amani
,
5°5.7’S
38°38’E
,
950–1000 m
asl
,
1974–1995
,
P. Bjørn
,
I.B. & H. Enghoff
,
C. Griswold
,
O. Lomholdt
,
O. Martin
,
N. Scharff
,
L. Sørensen
&
D. Ubick
leg., “on tree stump”, “in decaying wood” etc.
;
1 ♂
Tanga Region
,
Muheza
+
Korogwe District
, (
Nilo Forest
Reserve
)
940 m
asl
,
4°56’32.6”S
38°39’38.5”E
, trapsite 8 plot 59A, date?,
Frontier Tanzania
leg.
—
4 ♂♂
,
4 ♀♀
Muheza district
,
Nilo Forest
Reserve
,
1010–1240 m
asl
, submontane forest,
27.ii.— 21.vi.2001
,
Frontier Tanzania
leg.
;
1 ♀
Muheza District
,
Nilo Forest
Reserve
,
4°54’16”S
38°39’45”E
, lowland forest,
820 m
asl
,
10.vi.2000
,
Frontier Tanzania
leg.
Type locality.
Environs of Amani, East Usambara Mts.
Description.
SIZE (
Fig. 2
). Length
13–14 cm
; vertical body diameter
8.6–10.6 mm
(males), up to
11.8 mm
(females), 51–57 podous rings.
COLOUR. Live colour dark brown (pers. obs.). After 16 years in alcohol head, antennae, legs and telson orange yellow or brownish, body rings marbled greyish back to suture, then brownish, posterior ca. 10% amber brown; alternatively each body ring dark orange in anterior half, almost black in posterior half.
HEAD. Eyes with more ommatidia than in congeners: up to 60 ommatidia in up to 17 vertical and 8 horizontal rows.
GONOPODS (
Figs 8
G, 14, 15A). Sternum triangular, reaching almost as far distad as paracoxites, lateral edges slightly convex. Proplica ending in blunt-triangular process (
map
) separated by sinus from large apico-lateral, subsemicircular lobe (
lpl
). Apico-lateral lobe (
lpl
) reaching further distad than triangular lobe (
mpl
). Metaplica in anterior view basally with straight ridge continuing ca. to mid-length of coxite, apically with small mesal process (
map
) separated by sinus from sub-semicircular mid-distal process which again is separated by deep sinus from lateral birdhead-shaped process (
bh
), lateral “beak” of the latter long, slender, pointed, directed laterad. Birdheadshaped process reaching further distad than any other part of gonopod. Telopodite shortly after emergence from coxa with very long, slender, pointed, sinuous antetorsal process (
atp
); overall direction of process basad (the basad-mesad direction seen in
Fig. 14
is an artefact due to drying of the gonopods for scanning electron microscopy). Telopodite distal to antetorsal process with subrectangular flange, distal to flange slender, simple, without outgrowths.
Distribution
. Known only from lowland and submontane forest in the East Usambara Mts, 820–1010 (1240) m asl. Microhabitat notes include a tree stump and decaying wood.
Coexisting congener.
Coexists with
T. hamatus
in the East Usambara Mts, especially around Amani.
Infection with
Rickia gigas
. The long-celled
type
of
Rickia gigas
was found on the mesal-ventral sides of legpairs
2–7 in
males. Most specimens, including the
holotype
, were found to be infested with the short-celled
type
of
R. gigas
on the hind margin of the body rings of both sexes, in some cases on
all
body rings and even the preanal ring.