Otostigmus nudus Pocock, 1890

Lewis, John G. E., 2015, On Verhoeff’s Otostigmus subgenus Malaccopleurus, the nudus group of Otostigmus subgenus Otostigmus Porat, 1876, and Digitipes Attems, 1930, with a description of the foetus stadium larva in O. sulcipes Verhoeff, 1937, (Chilopoda: Scolopendromorpha: Scolopendridae), Zootaxa 4039 (2), pp. 225-248 : 237-239

Otostigmus nudus Pocock, 1890

( Figs 42–45)

Otostigma nudum Pocock, 1890: 247 . Plate 12, Fig. 3, 3 a, 3b. India.

Otostigmus nudus: Kraepelin, 1903: 108 .

Otostigmus ( O.) nudus: Attems, 1930b: 149 .

Otostigmus ( O.) nudus: Lewis, 1996: 827 , Figs 14–19 .

Digitipes periyarensis Joshi & Edgecombe, 2013: 115 , Figs 57 –67. Syn. nov. Kerala, India.

Diagnosis. Length up to 58 mm. Antennal articles 17, the basal three glabrous dorsally. Forcipular coxosternal tooth-plates longer than wide with 4+4 teeth. Tergites with complete paramedian sutures from 4, 5 or 6–20, marginate from 5, 6 or 8, with or without weak median keel and weak lateral corrugations. Sternites with paramedian sutures almost complete, with a median longitudinal depression on 5–19 and a weak small round posterior median depression on some sternites. Coxopleural process with two apical spines. Coxopleural pore-field narrow, scarcely widened anteriorly. Legs lacking tarsal, tibial and femoral spurs. Ultimate leg with prefemur, femur and tibia with well or poorly developed longitudinal grooves, prefemoral spines VL 3, VM 2 (3), M 0, DM 2 or 3 (three rows, 7 or 8 spines in toto).

Description of Holotype (based on Lewis (1996)). Colour (recorded by Pocock, (1890)) tergites pale olivaceous, sternites testaceous [reddish brown], cephalic plate, tergite 1 and maxillary sternite rufous, tarsi with pale green tint. Length 52 mm. Antennal articles 17+12[d], the basal three glabrous dorsally. Cephalic plate slightly longer than wide. Ratio of length to width of coxosternal tooth-plates 1.4:1 with 4+4 small teeth ( Fig. 42). A median longitudinal suture occupying anterior 25% of coxosternite. Forcipular trochanteroprefemoral process with a small medial denticle.

Tergites with complete paramedian sutures from 6–20, marginate from 8, with very weak lateral corrugations from 7–20, a very weak median keel from 5–21. Tergite of ultimate leg-bearing segment without a posterior median depression.

Sternites with more or less complete paramedian sutures in sulci from 2–19, with a median longitudinal depression on 5–19 and a weak small round posterior median depression on some sternites ( Fig. 43). Sternite of ultimate leg-bearing segment as long as wide with sides converging posteriorly and posterior margin very slightly concave. Coxopleural process short with two apical spines, no lateral or dorsal spines. The pore-field narrow, scarcely widened anteriorly ( Fig. 44).

Legs without tarsal spurs. Ultimate legs short and wide, the left prefemur with spines VL 3, VM 2, M 0, DM 2, CS 0. The right with VL 3, VM 2, M 0, DM 2 and a third very small dorsomedial possibly a corner spine. The dorsal surface of the prefemur, femur and tibia with extremely weak longitudinal grooves (Pocock notes upper surface of femur, patella and tibia obsoletely[indistinctly] and longitudinally sulcate) ( Figs 45).

Remarks. Otostigmus nudus would appear to be closely related to O. sulcipes from which it may be distinguished by its possession of 17 antennal articles rather than 18 and three ultimate leg prefemoral spine rows rather than four. It is morphologically very similar to Digitipes periyarensis Joshi & Edgecombe, 2013 and it is proposed below that D. periyarensis is a junior subjective synonym of O. nudus .

Pocock (1890) did not give a precise locality for O. nudus and Greg Edgecombe (personal communication) points out that the “sent from Madras by Mr Edgar Thurston” of Pocock’s title does not imply that his specimens were from Madras, rather that Madras was the port from which the material was shipped and that Pocock’s material may well have been sourced from the Western Ghats as is D. periyarensis .

Figures

FIGURES 1 – 8. Otostigmus sulcipes. 1. Forcipular coxopleural tooth-plates and left forcipular trochanteroprefemoral process, syntype ZMB 13364 Malacca, spm. in ethanol. 2. Sternite 11, the same. 3. Coxopleuron and sternite of ultimate leg-bearing segment, the same, ventral view. 4. Left ultimate leg prefemur and femur dorsal, the same. 5. Antennal article 3, syntype ZMB 13364, slide 3614, dorsal view. 6. Antennal articles 1 to 3, the same, ventral view. 7. Coxopleuron and sternite of ultimate legbearing segment syntype ZMB 13364, slide 3613, ventral view. 8. Ultimate leg prefemur, the same, ventral view. Scale bars = 1 mm except Figs 1, 3, 5 & 6 = 0.5 mm.

FIGURES 9–16. Foetus stadium Otostigmus sulcipes Malacca. 9. Distal four articles showing article 16 subdivided into two beneath the foetal cuticle spm 1. 10. Cephalic plate spm. 1. 11. Detail of cephalic plate showing possible ocelli spm. 2. 12. Pretarsus of second maxillary telopodite spm.1. 13. Forcipular coxosternal tooth-plates spm. 1. 14. Coxopleuron and sternite of ultimate leg-bearing segment spm. 1, ventral view. 15. Ultimate leg prefemur spm. 2. 16. Detail of ultimate leg prefemur showing developing spines. FIGURES 17–22. Otostigmus trisulcatus 17. Forcipular coxopleural tooth-plates syntype 13365. 18. Left forcipular trochanteroprefemoral process, the same. 19. Sternite 14, the same. 20. Coxopleuron and sternite of ultimate leg-bearing segment and ultimate leg prefemoral, the same, ventral view (coxal pores not shown). 21. Right coxopleuron syntype ZMB 13365, slide 4002. 22. Ultimate leg prefemur syntype 13365, dorsal view. Scale bars = 0.5 mm except Fig. 12, 13 & 16 = 0.1 mm.

FIGURES 51 – 59. Otostigmus cuneiventris. 51. Forcipular coxopleural tooth-plates, syntype spm. 2, Mapanja. 52. Sternite 12 syntype spm. 1. 53. Sternite of the ultimate leg-bearing segment syntype spm. 2. 54. Loose ultimate leg prefemur of a syntype ventral view. 55. Head and tergites 1 & 2, Bonge spm. 56. Sternite 12 Bonge spm. 57. Coxopleuron and sternite of ultimate legbearing segment and right ultimate leg prefemur Bonge spm. 58. Detail of right coxopleural process, ventral view. 59. Forcipular coxopleural tooth-plates Kilimanjaro spm. 1.