Polydrepanum Carl, 1932

Sankaran, Pradeep M. & Sebastian, Pothalil A., 2018, A new species of and a new transfer from the millipede genus Polydrepanum Carl, 1932 (Polydesmida, Paradoxosomatidae, Polydrepanini), Zootaxa 4471 (1), pp. 169-178 : 170

Genus Polydrepanum Carl, 1932

Diagnosis. Medium - sized (18–25 mm) Polydrepanini with a normal pore formula: 5, 7, 9, 10, 12, 13, 15-19. Body with 20 segments, metaterga conspicuously nodose. Head slightly wider than collum. Paranota weakly developed. Metazonites setose or not, with deep, beaded transverse sulcus. Pleural keels visible only on first few segments. Male tarsal brushes present. Male femora 1 & 2 or only 2 modified. A well-developed sternal lamella between male coxae 4. Gonopodal prefemur short. Gonopodal femorite with clear evidence of torsion except in P. fissum sp. nov., which has incomplete torsion of gonopodal femorite. Seminal groove running along dorsal face of femorite. Entire telopodite strongly torsate. A basal postfemoral process absent. Solenophore divided into several branches, distally sickle-shaped, showing only a lamina lateralis with a mesal extension. Solenomere long and flagelliform with a strong distal curvature, almost entirely enclosed by lamina lateralis ( Carl 1932; Attems 1937; Jeekel 1968; Golovatch 1984).

Type species: Polydrepanum tamilum Carl, 1932 , by monotypy.

Relationship. Within Polydrepanini , Polydrepanum seems to be particularly similar to the formally monotypic Indian genus Telodrepanum as both share the sickle-shaped solenophore and the distally curved, flagelliform solenomere ( Carl 1932: fig. 52; Golovatch 1984: fig. 8; herein Fig. 5A–B ). However, Polydrepanum spp. can be distinguished from Telodrepanum spp. by the following combination of characters: solenomere sheathed by solenophore ( Telodrepanum spp. with solenomere not sheathed by solenophore), only distal part of solenophore sickle-shaped (entire solenophore in Telodrepanum spp. sickle-shaped) and lacking postfemoral process ( Telodrepanum spp. with anteriorly oriented postfemoral process) (see Carl 1932: figs 16–18, 52–54; Golovatch 1984: figs 8–11, 14–17; herein Figs 3E–F , 4A–B , 6A–B ).

Figures

FIGURE 3. Polydrepanum fissum sp. nov., male legs (A–D) and gonopod (E–F). A: Leg pair I, ventral view (insets adenostyle on right femur 1, lateral view (left) and tarsus of the right leg showing tarsal brush, lateral view (right)). B: Left leg of haplosegment 2, mesal view (inset tarsus of the same showing tarsal brush, mesal view). C: Left leg of haplosegment 3, mesal view (inset tarsus of the same showing tarsal brush, mesal view). D: Tarsus of right anterior leg of diplosegment 4 showing tarsal brush, mesal view. E: Right gonopod, ventral view. F: Same, mesal view. Scale bars: A–C, E–F 0.5 mm; D 0.2 mm.

FIGURE 4. Polydrepanum fissum sp. nov.. A: Right gonopod, ventral view. B: Same, mesal view. C: Same, lateral view. Abbreviations: C = cannula, dlLF = distolateral lobe of femorite, dlLL = distolateral lobe of lamina lateralis, F = femorite, FF = fold of femorite, GC = gonocoxa, LL = lamina lateralis, LLp = lateral lamellate process of solenophore, mLL = mesal extension of lamina lateralis, mTp = mesal triangular process of solenophore, MWp 1 & 2 = membranous wing-like process of solenophore 1 and 2, PF = prefemur, SG = seminal groove, Sm = Solenomere, Sp = Solenophore. Arrows indicate tip of solenomere (3), branches of solenophore tip (1–2) and distoventral, long, stiff seta of prefemur (4). Scale bars: A–B 0.5 mm; C 0.2 mm.

FIGURE 5. Original illustrations of Telodrepanum badaga Carl, 1932 (A) and Polydrepanum implicatum Carl, 1941 (B) showing structural similarities (reproduced from Carl (1932, 1941)). Arrows indicate sickle-shaped solenophore (1) and postfemoral process (2).

FIGURE 6. Previously known Polydrepanum spp.. A: Polydrepanum asperrimum (Carl, 1932) (reproduced from Carl (1932)). B: Polydrepanum horridum Golovatch, 1984 (reproduced from Golovatch (1984)). C: Polydrepanum tamilum Carl, 1932 (reproduced from Carl (1932)). D–F: Undescribed Polydrepanum spp.: D: Polydrepanum sp. 1; E: Polydrepanum sp. 2; F: Polydrepanum sp. 3 (all reproduced from Bano & Murthy (1997)). All figures not to scale.