Scaptodesmus Cook, 1896: 16

Fiemapong, Armand Richard Nzoko, Blandenier, Quentin, Tamesse, Joseph Lebell & Mitchell, Edward A. D., 2025, Taxonomic review of the Afrotropical millipede genus Scaptodesmus Cook, 1896 (Diplopoda, Polydesmida, Chelodesmidae), with integrative descriptions of three new species from Cameroon, Zootaxa 5696 (3), pp. 361-384 : 365-380

Scaptodesmus Cook, 1896: 16 (original description).

urn:lsid:zoobank.org:act:

Type-species: Scaptodesmus porati Cook, 1896 , Cameroons, by original designation.

Historical diagnosis. According to Cook (1896), the genus Scaptodesmus is easily recognized by the presence of ozopores located on distinct excavations at the lateral margins of the carinae, the dorsum very slightly convex, and the telson with the marginal processes very strongly developed.

Updated diagnosis. A genus of Chelodesmidae (subfamily: Prepodesminae ), distinguished by the absence of a conspicuous paramedian or dorsomedian horn on the metaterga; subrectangular, elevated, horizontal paranota with dentate lateral, anterior, and posterior margins, combined with a slightly convex dorsum ( Figs 2A , 3 , 7 , 10 ); the normal pore formula (5, 7, 9, 10, 12, 13, 15–19), with ozopores being located on distinct excavations along the lateral margins of the paranota ( Figs 2A , 4A , 11A–B , 8B–D ), gonopod telopodites suberect, in situ directed forward ( Fig. 8F ), held parallel to each other, not crossing mesally; femoral process subcylindrical, usually densely setose, elongated, partly erect, taking up ca. 2/3 total telopodite length, without femorite, with a complex dorsal postfemoral process ( pfp) demarcated from acropodite by a distinct cingulum; acropodite twisted and divided into two lobes ( Figs 2C, D , 5 , 9 , 12C–F ). External branch forming a solenophore ( sph), larger than internal branch, or solenomere ( slo), supporting a seminal groove all along ( Fig. 2C–D ).

Key to species of Scaptodesmus

The key below is based on male characters and therefore, Scaptodesmus porati Cook, 1896 is excluded as the gonopods have never been illustrated.

1. Gonopod postfemoral process undivided, complex in structure, folded into a lateral groove, or rake-shaped and bearing 3–4- minute denticles distally................................................................................ 2

- Gonopod postfemoral process bifurcate and mostly simple in structure........................................... 3

2. Solenophore broad, opposite a relatively thin and falcate solenomere branch, lacking a solenomere proper at apex ( Fig. 8 ).................................................................................... S. manengouba sp. nov.

- Solenomere branch about half as wide as solenophore, with a distinct, small solenomere proper at apex ( Figs 4E, 4G ).............................................................................................. S. kala sp. nov.

3. Curvature of postfemoral process showing a small inner blade at mid-length ( Figs 11D, 11F ), tips of the two bifurcate branches of postfemoral process subequal in size............................................... S. vandenspiegeli sp. nov

- Postfemoral process without small inner blade at mid-length of curvature, tips of the two bifurcate branches unequal in size ( Fig. 2C )................................................................................. S. granulosus .

Figures

FIGURE 2. Scaptodesmus granulosus (Attems, 1931), A. Paranota. B. telson. C, D & E. Gonopods of a male (ZMH) from Buea in Cameroon. C. Right gonopod, mesal view, D. Tip of right gonopod, ventro-mesal view. E. solenomere branch showing the seminal groove. After Attems (1931), not to scale. Labels added by present authors. Abbreviations: slo, solenomere lobe; sl, solenomere proper; sph, solenophore; pfp, postfemoral process.

FIGURE 3. Scaptodesmus kala sp. nov, female paratype (NHMN-62-4). A, B & C. Habitus, dorsolateral, ventrolateral and lateral views, respectively. Scale bars: 1.0 mm.

FIGURE 4. SEM micrographs of Scaptodesmus kala sp.nov, male paratype, (ARNF). A. Poriferous paraterga of midbody segments dorsal views, B. posterior part of body dorsal views, C & D. anterior legs and ventral views showing sternal region and gonopod aperture, respectively. Scale bars: 1.0 mm. (A, B, C, D).

FIGURE 5. SEM micrographs of Scaptodesmus kala sp. nov, male paratype, A) Tip of left gonopod, lateral view; B. left gonopod, mesal view; C. right gonopod lateral view. Abbreviations: slo, solenomere lobe; sph, solenophore; pfp, postfemoral process. Scale bars: 400 µm (A), 1.0 mm (B, C)

FIGURE 7. A, B & C. Scaptodesmus manengouba sp. nov, male paratype (NHMN-62-11). A. habitus, lateral view; B. ventral view, C. dorsal view. Scale bars: 1.0 mm (A, B, C)

FIGURE 8. SEM micrographs of Scaptodesmus manengouba sp. nov, male paratype (ARNF). A. head collum and first segment, dorsal view; B. caudal margin, latero-pleural view; C. four first anterior body segment anterior view; D. mid-body segment, lateral view; E. mid-body segment showing pro and metazonae; F. sternal region, gonopod aperture and left gonopod in situ, ventral view. Scale bars: 1.0 mm (A, B, C, D, E & F).

FIGURE 9. SEM micrographs of Scaptodesmus manengouba sp. nov, male paratype (ARNF). A & B. right gonopod, mesal view; C. left gonopod, dorsal view. Abbreviations: slo, solenomere lobe; sph, solenophore; pfp, postfemoral process. Scale bars: 500 µm (A); 200 µm (B); 300 µm (C).

FIGURE 10. Scaptodesmus vandenspiegeli sp. nov, male paratype (NHMN-62-14), habitus, dorsal view. Scale bar: 5 mm.

FIGURE 11. SEM micrographs of Scaptodesmus vandenspiegeli sp. nov, male paratype (ARNF). A & B. mid body paraterga, dorsal and ventral view, respectively; C. dorsum presenting pro and metazonae margin; D. legs of mid-body segment, ventral view; E & F. cross-section of a midbody segment, caudal view. Scale bars: 1.0 mm (A, B, C, D, E, F)

FIGURE 12. SEM micrographs of Scaptodesmus vandenspiegeli sp. nov, male paratype, (ARNF). A. head and anterior margin of the collom, dorsal view; B. sternal region and gonopod aperture, ventral view; C-E. right gonopod, mesal view; D-F. left gonopod, dorsal view. Abbreviations: slo, solenomere lobe; sph, solenophore; pfp, postfemoral process. Scale bars: 1.0 mm (A, B, C, D); 400 µm (E, F)