Bactrodesmus grandis, Golovatch, Sergei I., Fiemapong, Armand Richard Nzoko & VandenSpiegel, Didier, 2019

Golovatch, Sergei I., Fiemapong, Armand Richard Nzoko & VandenSpiegel, Didier, 2019, 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, ZooKeys 891, pp. 31-59 : 31

publication ID

https://dx.doi.org/10.3897/zookeys.891.46986

publication LSID

lsid:zoobank.org:pub:4B0C5A33-87F4-4B20-B837-6723C0BEA8B2

persistent identifier

https://treatment.plazi.org/id/AF5E4B4D-7A9B-426D-A87D-16EC8FFB61BD

taxon LSID

lsid:zoobank.org:act:AF5E4B4D-7A9B-426D-A87D-16EC8FFB61BD

treatment provided by

ZooKeys by Pensoft

scientific name

Bactrodesmus grandis
status

sp. nov.

Bactrodesmus grandis sp. nov. Figs 1B, C View Figure 1 , 4 View Figure 4 , 5 View Figure 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 View Figure 1 ).

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 View Figure 4 ). 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 View Figure 4 ), 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 View Figure 4 ), 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 View Figure 4 ). Starting with paraterga 5 or 6, caudal corner increasingly sharp and drawn back past rear tergal margin ( Fig. 4 A–C, H View Figure 4 ). 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 View Figure 4 ). Pleurosternal carinae traceable as very faint ridges or lines on most segments ( Fig. 4A, B View Figure 4 ). Epiproct short, conical, flattened dorsoventrally. Hypoproct semi-circular, setae strongly separated and borne on minute knobs.

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 View Figure 4 ): legs 1 ( Fig. 4J View Figure 4 ) with increasingly inflated pretarsal podomeres; legs 2 ( Fig. 4K, L View Figure 4 ) 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 View Figure 4 ) resembling legs 1, but their prefemora and femora especially densely setose ventrally.

Gonopods ( Fig. 5 View Figure 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.

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 Mauriès (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).