Polydrepanum fissum Sankaran & Sebastian, 2018

Golovatch, Sergei I., Aswathy, Mathilakath Dasan, Bhagirathan, Usha & Sudhikumar, Ambalaparambil Vasu, 2021, Review of the millipede tribe Polydrepanini, with the description of a new species from Kerala state, southern India (Diplopoda, Polydesmida, Paradoxosomatidae, Alogolykinae), Zootaxa 5068 (4), pp. 485-516 : 489

Polydrepanum fissum Sankaran & Sebastian, 2018

(= Grammorhabdus fissus ( Sankaran & Sebastian, 2018)) , comb. nov.

Figs 6–8

Polydrepanum fissum Sankaran & Sebastian, 2018: 170 , figs 1, 4–7 (D). India, Tamil Nadu.

Remarks. Among the most important characters of this species are the presence of adenostyles on both male femora 1 and 2, coupled with the gonofemorite being fairly slender and long, devoid of any traces of torsion, delimited from the acropodite by a very distinct postfemoral sulcus/cingulum (su), while the solenophore (sph) is peculiar in shape: two small, subdentiform, laterobasal lobes (a), and two similarly small, subdentiform, apicomesal lobes (b) lying distal to the basal loop (k) of a free solenomere (sl). Base of sph on ventral side forming an elongated and undulated protecting lobe (lo) to shield the basal sl loop. Distal half of both sph and sl subcircular and directed ventrad ( Figs 6–8 ).

It is the unusually elongated and undulated lo that Sankaran and Sebastian (2018) must have mistaken for a lamina lateralis. However, that homologization is hardly correct, because the same membranous structure in the undoubtedly very similar P. asperrimum is interrupted in the subbasal and middle parts, being largely traced only subapically ( Figs 3–5 ).

Because the gonopodal femorite in P. fissum is untwisted ( Figs 6–8 ), unlike that of the type species P. tamilum (see below and Figs 17–19 ), but very much like in Grammorhabdus asperrimus , contrary to Sankaran and Sebastian (2018), we are inclined to assign P. fissum to Grammorhabdus Carl, 1932 , comb. nov.

Figures

FIGURES 6–8. Grammorhabdus fissus (Sankaran & Sebastian, 2018). 6, 7. Right gonopod, ventral and mesal views, respectively. 8. Distal half of right gonopod, lateral view. After Sankaran and Sebastian (2018). Abbreviations: a and b, apicomesal lobes; ad, adenostyle; ca, cannula; cx, coxite; fe, femorite; k, basal loop of solenomere; lo, lateral lobe; pfe, prefemoral portion; sl, solenomere; sph, solenophore; su, distofemoral sulcus. Scale bars: 0.5 mm (6, 7) and 0.2 mm (8).

FIGURES 1–5. Grammorhabdus asperrimus Carl, 1932. 1. Male leg 1, lateral view. 2. Male leg 2, lateral view. 3. Entire left gonopod, mesal view. 4, 5. Distal half of left gonopod, lateral view. 1–4: after Carl (1932), 5: after Jeekel (1980B). Abbreviations: a and b, apicomesal spines; ad, adenostyle; ca, cannula; cx, coxite; fe, femorite; k, basal loop of solenomere; lo, lateral lobe; pfe, prefemoral portion; sl, solenomere; sph, solenophore. Drawn not to scale.

FIGURES 16–20. Polydrepanum tamilum Carl, 1932. 16. Male leg 2, lateral view. 17. Entire left gonopod, mesal view. 18. Distal half of left gonopod, lateral view. 19. Entire right gonopod, mesal view. 20. Distal half of right gonopod, sublateral view. 16–18: after Carl (1932); 19, 20: after Jeekel (1980b). Abbreviations: a and b, dorsal distofemoral processes; ad, adenostyle; lo, lateral protecting lobe/shield; k, basal loop of solenomere; sl, solenomere; sph, solenophore. Drawn not to scale.