Sterropristes violaceus Muadsub and Panha

Muadsub, Sawitree, Sutcharit, Chirasak, Pimvichai, Piyatida & Enghoff, Henrik, 2012, Revision of the rare centipede genus Sterropristes Attems, 1934, with description of a new species from Thailand (Chilopoda: Scolopendromorpha: Scolopendridae), Zootaxa 3484, pp. 35-52 : 46-50

Sterropristes violaceus Muadsub and Panha n. sp.

( Figures 1 G–I, 2, 6C, 9–11 and Table 1 )

Type specimens. Holotype CUMZ 3207 ( Figs 10 , 11 ). Type locality: Koh Si, Similan Islands, Phangnga Province, Thailand (8º 50’ N, 97º 49’ E). 6 April 2010. S. Muadsub and S. Panha. Paratypes CUMZ 3208 and ZMUC 00021424, same data as holotype. Similan Islands are located in the Andaman Sea, south-western Thailand, 70 km off the coast from Kuraburi district, Phangnga Province. The Islands are composed of 9 small islands in a line north to south.

Other specimen. CUMZ 3209, Surin Islands, Phangnga, Thailand (9º 25’ N, 97º 52’ E). 8 April 2012. S. Muadsub and P. Pimvichai.

Etymology. The specific name is a Latin adjective meaning purple or violet. The new species is dedicated to Her Royal Highness Princess Maha Chakri Sirindhorn, who initiated the Plant Genetic Conservation Project – violet is the colour of her royal banner.

Diagnosis. Antennal articles 1 to 4 glabrous or with very few setae, articles 5 to 17 densely setose. Bases of coxosternal tooth plates meeting at right angles. Forcipular tarsungula slightly curved, internal margins with 11–13 saw teeth. Tergites 6 to 20 and sternites 11 to 19 with complete paramedian sutures. Sternite of ultimate leg-bearing segment with strongly converging lateral margins. Coxopleura of ultimate legs truncated and equivalent in length to sternite of ultimate leg-bearing segment. Ultimate legs thickened; prefemora, femora and tibiae similar in length, prefemora equal in length and width, femora and tibiae longer than their widths; dorsal sides of femora with short posterior grooves; ventral sides of tibia and tarsus 1 prominently convex. Legs 1 and 2 both with one tibial spur, legs 1 to 14 each with two tarsal spurs, legs 15 to 20 each with one tarsal spur and legs 1 to 20 each with two pretarsal accessory spurs.

Sterropristes violaceus Muadsub and Panha n. sp. differs from S. sarasinorum by the latter species having only 9 saw teeth on the forcipular tarsungula (versus 11–13), antennal articles 1 to 7 glabrous, coxopleura longer than the sternite of the ultimate leg-bearing segment, a posterior dorsal groove on the ultimate legs being present on the prefemora and femora, and the ventral sides of both tarsomeres (but not the tibia) being prominently convex. The distinguishing characters of S. metallicus vis-a-vis this new species are that in S. metallicus the coxopleura of the ultimate legs are longer than the sternite of the ultimate leg-bearing segment, and the ventral sides of tarsi 1 are not prominently convex.

Description of holotype. Body length about 33 mm. Living animals: cephalic plate, tergites and ultimate legs dark purple, antennae and locomotory legs light purple. Colour of preserved specimen: cephalic plate and tergites dark purple, antennae, locomotory and ultimate legs light purple.

Cephalic plate smooth, anterior part semi-circular, posterior margin straight, surface almost glabrous but few short setae; four ocelli.

Antennae dorso-ventrally flattened, reaching back to third tergite, with 17 articles ( Figs 10 A, C, 11A). Articles 1 to 4 wide, almost glabrous, with few short setae on both dorsal and ventral side. Articles 5 to 17 densely pubescent with short setae, terminal article longer than wide, width of penultimate article width about 1/3 the width of first article.

Forcipular coxosternal tooth plates with 4+4 teeth, two inner teeth higher than the two outer ones, basal borders of tooth plates meeting at right angles, surface of plates with a few short setae. Forcipules without trochanteroprefemoral processes; tarsungula with 13 saw teeth on internal margins ( Figs 10 B, 11A, B). Second maxillae with few scattered setae, without accessory spur. First maxilla with few scattered setae.

Tergites smooth with scattered setae on surface. First tergite about three times longer than second, not overlapping cephalic plate, lacking furrows or sutures.

Tergites 2 to 5 with short anterior and posterior paramedian sutures, tergites 6 to 20 with complete sutures ( Fig. 10 A, D, F). Tergite of ultimate leg-bearing segment margined laterally, without posterior median depression, posterior margin with rounded apex. Ten pairs of oval spiracles, those on segment 3 largest ( Fig. 1 G) but not conspicuously larger than those on subsequent segments; spiracles present on segment 7 ( Fig. 1 C); wall and floor of spiracular atrium bearing large humps.

Sternites smooth, paramedian sutures on anterior half of sternites 4 to 10, complete sutures on sternites 11 to 19 ( Fig. 10 C, E, G). Sternite of ultimate leg-bearing segment with converging lateral margins and concave posterior margins. Coxopleura of ultimate legs truncate, without processes and spines, similar in length to sternite of ultimate leg-bearing segment, covered with many small pores ( Figs 10 G, 11E).

Locomotory legs with scattered setae, prefemora and femora flattened. Tarsus 1 longer than tarsus 2. Legs 1 and 2 both with one tibial spur, legs 1 to 14 each with two tarsal spurs, legs 15 to 20 each with one tarsal spur, legs 1 to 20 each with two pretarsal accessory spurs ( Fig. 11 A, C, D).

Ultimate legs short and very thickened, dorsally flattened, surface smooth without spines. Prefemora, femora and tibiae similar in lengths, prefemora equal in length and width, femora and tibiae longer than wide, glabrous and glossy; prefemora and femora with deep furrow on ventral sides ( Figs 10 G, 11F), femora with short grooves on posterodorsal sides ( Figs 10 H, 11G). Tibiae and tarsus 1 prominently convex on ventral sides ( Figs 10 H, 11F), tarsus 1 longer than tarsus 2, pretarsus longer than tarsus 2.

Remarks. Four paratypes from Similan Islands vary in length from 23 to 30 mm. The smallest specimen (23 mm; with one ultimate leg) has 11 saw teeth on the forcipular tarsungula, a femoral spur is absent, one tibial spur on each of legs 1 to 3 and two tarsal spurs on each of legs 1 to 4. Two specimens (25 mm and 24 mm) have the same number of saw teeth as in the holotype ( Fig. 9 ); both have complete paramedian sutures on tergites 5 to 20, one femoral spur on leg 1 or both legs 1 to 2, one tibial spur on each of legs 1 to 3 or only on legs 1 and 2, and two tarsal spurs on each of legs 1 to 4. The largest specimen (30 mm) is nearly of similar size to the holotype, but it differs in having 12 saw teeth on the forcipular tarsungula, a femoral spur on leg 1, one tibial spine on leg 1, and two tarsal spines on legs 1 and 2.

The specimen from Surin Islands (33 mm; without ultimate legs) is closest in size to the holotype, but it has 11 teeth on the forcipular tarsungula, one femoral and one tibial spur on leg 1, and two tarsal spurs on each of legs 1 to 3.

description except where noted.

Characters S. sarasinorum S. metallicus S. metallicus S. violaceus n. sp.

(holotype) (topotypes)

Figures

FIGURE 1. Spiracles of segments 3, 5 and 7 (left to right, respectively). A – C. Holotype NMB 432 a of Sterropristes sarasinorum Attems, 1934. D – F. Specimen CUMZ 3205 of Sterropristes metallicus from Penang Botanical Gardens, Penang, Malaysia. G – I. Holotype CUMZ 3207 of Sterropristes violaceus Muadsub and Panha n. sp.

FIGURE 9. Relationship between body length and number of tarsungula denticles of Sterropristes species.

FIGURE 10. Holotype CUMZ 3207 of Sterropristes violaceus Muadsub and Panha n. sp. A. Head and leg-bearing segments 1 to 5. B. Forcipules. C. Ventral view of head and leg-bearing segments 1 to 5. D. Tergites 11 to 15. E. Sternites 11 to 15. F. Tergites 18 to 21 and ultimate leg. G. Sternites 18 to 21, sternite of ultimate leg-bearing segment almost the same length as coxopleura. H. Lateral view of segments 19 to 21 and showing convex underside of ultimate leg tibia.

FIGURE 11. Drawings of Sterropristes violaceus Muadsub and Panha n. sp., holotype CUMZ 3207. A. Antennae, head ventral and segment 1. B. Forcipules. C. Tergites 14 to 15. D. Sternites 14 to 15. E. Sternite of ultimate leg-bearing segment almost the same length as coxopleura. F. Lateral view of ultimate leg showing convex underside of tibia. G. Oblique view of ultimate leg showing posterior femur groove.