Trichopolydesmidae from Cameroon, 2: A species-level reclassification of Afrotropical trichopolydesmids (Diplopoda, Polydesmida), with two new species and two new records from Cameroon, and two new species from the Nimba Mountains, Guinea
Author
Golovatch, Sergei I.
Author
Fiemapong, Armand Richard Nzoko
Author
VandenSpiegel, Didier
text
ZooKeys
2019
891
31
59
http://dx.doi.org/10.3897/zookeys.891.46986
journal article
http://dx.doi.org/10.3897/zookeys.891.46986
1313-2970-891-31
4B0C5A3387F44B20B8376723C0BEA8B2
4067E2E6C04D5EA2BE891D26C57C6D9F
Bactrodesmus grandis
sp. nov.
Figs 1B, C
,
4
,
5
Type material.
Holotype
♂ (MRAC 22843), Guinea, Nimba Mountains, near cave 2, Serengbara, camp 3, ca 1035 m a.s.l., litter, 2.V.2019, A. Henrard, D. VandenSpiegel, C. Allard et al. leg. (Nimba 2019-41).
Paratypes
: 1 ♀ (MRAC 22844), same locality, together with holotype: 2 ♂, 1 ♀ (MRAC 22845), 2 ♂ (MRAC 22862), 1 ♂ (SEM, MRAC 22846), 1 ♂ (ZMUM Rd 4628), same locality, forest; ca 975 m a.s.l., 2.V.2019, A. Henrard, D. VandenSpiegel, C. Allard et al. leg. (Nimba 2019-49).
Diagnosis.
Differs from both other species of the genus by ♂ legs 1-3 being clearly enlarged and modified, vs. ♂ legs 2 or 2 and 3, from
B. bicornis
also by three (vs. two) transverse rows of tergal setae and the collum which is narrower than the head, from
B. claviger
by the considerably larger body.
Name.
To emphasize the relatively large body and clearly enlarged ♂ legs 1-3; adjective.
Description.
Length ca 8 (♂, including holotype) or 9 mm (♀), width of midbody pro- and metazonae 1.0 and 1.3 mm (♂, including holotype) or 1.2 and 1.5 mm (♀), respectively. Coloration in alcohol marbled light brown to reddish brown, venter and legs usually lighter, light grey-brown to nearly pallid (
Fig. 1B, C
).
Body with 20 segments in both sexes. Tegument very delicately micro-alveolate, mainly slightly shining. Head densely micropilose, devoid of epicranial modifications, but genae roundly squarish and very strongly swollen laterally; gnathochilarium without modifications (
Fig. 4G
). Interantennal isthmus 1.8 times diameter of antennal socket. Antennae long and strongly clavate, reaching back past segment 3 (♂) when stretched dorsally. In length, antennomere 3 = 6> 5> 2 = 4> 7> 1; antennomere 6 the largest, antennomeres 5 and 6 each with a distinct, round, distodorsal field of minute sensilla. In width, collum <segments 2 and 3 <head = 4 <5-16; thereafter body gradually tapering towards telson. Collum ellipsoid, transversely oval, like all following metaterga with three transverse, regular rows of setae. Tergal setae largely abraded, medium-sized, each ca 1/4-1/5 as long as metatergum, bacilliform and longitudinally ribbed, set on minute knobs, growing slightly longer toward telson, 3-4 additional setae present at lateral margin of paraterga (
Fig. 4
A-E
, H
), always 3+3 in each row on postcollum metaterga. Dorsal surface of metaterga nearly smooth, regularly convex. Paraterga medium-sized, set at around upper 1/3 of metazonae (
Fig. 4
A-C
, E, H
), visible starting with collum, often slightly upturned caudally, faintly, but regularly rounded and bordered, lateral incisions absent, with minute setigerous knobs present in their stead, including ones located at caudal corners. Paraterga 2 slightly enlarged, more strongly declined and broadly rounded compared to following ones (
Fig. 4A
). Starting with paraterga 5 or 6, caudal corner increasingly sharp and drawn back past rear tergal margin (
Fig. 4
A-C
, H
). Pore formula normal: 5, 7, 9, 10, 12, 13, 15-19. Ozopores small, round, opening flush dorsally near caudal corner of poriferous paraterga. Stricture between pro- and metazonae wide, shallow. Limbus very finely microspiculate. Spiracles very small, located on short cones (
Fig. 4K
). Pleurosternal carinae traceable as very faint ridges or lines on most segments (
Fig. 4A, B
). Epiproct short, conical, flattened dorsoventrally. Hypoproct semi-circular, setae strongly separated and borne on minute knobs.
Figure 4.
Bactrodesmus grandis
sp. nov., SEM micrographs of a ♂ paratype
A
anterior part of body, lateral view
B-D
midbody segments, lateral, dorsal and ventral views, respectively
E
cross-section of a midbody segment, caudal view
F
fine tergal structure, dorsal view
G
head, ventral view
H
midbody paratergum, lateral view
I
from right to left, legs 1-3 in situ, lateral view
J
leg-pair 1, oral view
K
leg 2 and base of leg 3, frontoventral view
L
coxae 2, subventral view
M
leg 3 and bases of several following legs, frontoventral view. Scale bars: 0.2 mm (
A-E
), 0.1 mm (
G,
I-K
, M
), 0.05 mm (
I, L
), 0.02 mm (
F
).
Sterna wide, unmodified, setose. Legs rather long and slender, ca 1.3-1.4 (♂) or 1.1-1.2 times (♀) as long as midbody height; in length, tarsus> femur> prefemur> coxa = postfemur = tibia. Tarsal brushes present only on ♂ legs 1 and 2; ♂ legs 1-3 conspicuously enlarged (
Fig. 4I
): legs 1 (
Fig. 4J
) with increasingly inflated pretarsal podomeres; legs 2 (
Fig. 4K, L
) with each coxa caudally supplied with what seems to be a gland whose wide orifice is surrounded by a whorl of setae while the interior carries bundles of abundant, very long, sharp, distally entangled filaments; tibiae 2 particularly strongly swollen, while tarsi 2 somewhat shortened, dorsally flattened and spoon-shaped; legs 3 (
Fig. 4K, M
) resembling legs 1, but their prefemora and femora especially densely setose ventrally.
Gonopods (
Fig. 5
) complex, with particularly strongly enlarged, globose and nearly smooth coxae (cx), both forming a very deep gonocoel, both clearly rimmed apically and with 2+2 especially strong setae mediobasally near place of coxal fusion; one small rounded lobe each present on cx distolaterally (lol) and distomesally (lom); cannulae relatively small, as usual. Telopodites deeply sunken inside gonocoel, very poorly exposed beyond it, each starting with a setose funnel-shaped part (fu) marking the orifice for the cannula to enter and the beginning of a seminal groove, the latter quickly passing onto a short, stout, slightly curved, distad attenuating solenomere (sl) branch fully concealed inside gonocoel; basal part of telopodite extended mesally along fu into a distinct fold turning apically into a long, gently and regularly curved, laterad directed spine (sp); lateral part of telopodite divided distally by a clear-cut suture (su) into two sections, both being simple and stout slabs, but distal one bearing a meso-central membranous sac to protect sl tip.
Figure 5.
Bactrodesmus grandis
sp. nov., gonopods of ♂ paratypes
A, B
left gonopod, subventral and ventromesal views, respectively
C, D
right gonopod, ventrolateral and ventral views, respectively
E, F
right gonopod, lateral and mesal views, respectively. Abbreviations:
cx
coxa,
lol
distolateral lobe of coxa,
lom
distomesal lobe of coxa,
fu
basal funnel of telopodite,
sl
solenomere,
sp
spine,
su
parabasal sulcus on telopodite. Scale bars: 0.1 mm.
Remarks.
The size, external structures and gonopodal conformation of
B. grandis
sp. nov. match closely those as described and depicted for
B. bicornis
by
Demange and
Mauries
(1975)
. The latter species is 8.0 mm long and 1.5 mm wide. Its hypertrophied gonopodal coxa is likewise nearly smooth and shows two small distal lobes, lol and lom. The short spiniform solenomere (sl), the long mesobasal spine (sp) and the two-segmented lateral part of the gonotelopodite look much like, and are located similarly in
B. grandis
sp. nov. Unfortunately, even though the gonopodal structure of
B. claviger
remains unknown, the genus
Bactrodesmus
can presently be redefined (see above).