Digitipes periyarensis, Joshi, Jahnavi & Edgecombe, Gregory D., 2013

Joshi, Jahnavi & Edgecombe, Gregory D., 2013, Revision of the scolopendrid centipede Digitipes Attems, 1930, from India (Chilopoda: Scolopendromorpha): reconciling molecular and morphological estimates of species diversity, Zootaxa 3626 (1), pp. 99-145 : 116

Digitipes periyarensis n. sp.

( Figs 57–67 )

Digitipes putative species 4. Joshi and Karanth, 2012: figs 2, 3.

Type specimens. Holotype CES 091037, female, from Periyar, Kerala, India, 9°58402 N 77°34902 E, leg. J. Joshi, ix.2009. Paratype CES 091038, female, from type locality, same collection details.

Etymology. For the Periyar region.

Diagnosis. Cephalic plate slightly longer than wide. Basal three antennal articles glabrous dorsally. Forcipular tooth plates longer than wide. Paramedian sutures nearly complete on most sternites. All legs lacking tarsal, tibial and femoral spurs. Femur of ultimate leg with pair of longitudinal grooves on dorsal surface, the more medial of them contiguous with a longitudinal groove on the prefemur and tibia; tarsus of ultimate legs markedly more slender than short, robust tibia and femur. Coxopleural process short; pores relatively sparse.

Description. Length to 58 mm. 17 antennal articles; basal three articles glabrous dorsally, two glabrous ventrally. Anterior longitudinal median furrow at most ca 20% length of cephalic plate, considerably shorter in holotype ( Fig. 57 ).

Cephalic plate and T1 orange; anterior tergites mixed blue and yellow-brown; tergites in posterior half of trunk mostly light brown with blue margins; antennae and legs 1–20 pale yellow apart from pale blue tarsi on leg 20.

Forcipular coxosternal tooth plates longer than wide, markedly so in holotype ( Figs 58, 59 ); four main teeth, not arranged in groups, the outer tooth smaller than the inner three; base of tooth plates defined by relative acute oblique sutures diverging at 105°–125°. Trochanteroprefemoral process with indistinctly defined teeth along inner margin.

Second maxillary claw with slender accessory spurs. Article 2 of telopodite bearing a slender spine distally.

Tergites with paramedian sutures complete from TT4 or 5, short suture confined to anterior edge of TT2–3. Tergites marginate from 5 or 6. Tergites smooth, lacking median ridge or keels ( Fig. 66 ) apart from weak, incomplete median keel on tergite of ultimate leg-bearing segment; lateral part of posterior tergites with low, irregularly anastomosing ridges.

Sternites with paramedian sutures nearly complete in most segments, especially in anterior part of trunk, those in posterior few segments ca 80% length of sternite.

Tergite of ultimate leg-bearing segment with lateral margins gently converging posteriorly, posterolateral margins mostly straight, converging to a broad, evenly rounded posteromedial margin ( Fig. 61 ). Sternite of ultimate leg-bearing segment with sides converging posteriorly, posterior margin gently concave ( Fig. 62 ).

Coxopleural process short, barely inflected from posterolateral margin of coxopleuron in ventral view ( Fig. 62 ), with two apical spines, lacking lateral spine(s). Pore field terminating strongly beneath dorsal margin of coxopleuron ( Fig. 60 ); pores relative sparse; non-porose area on coxopleural process short. Ultimate leg prefemur with width at distal end nearly 40% its length, of nearly equal width along its length ( Fig. 64 ). Prefemoral spines robust, with a short, curved apex ( Fig. 63 ): VL 3, VM 2(3), DM 2. Femur with width at its distal end 40–50% its length ( Fig. 64 ). Dorsal, medial and lateral surfaces of prefemur and femur rugose, with large, shallow pits; similar pits adjacent to longitudinal groove on dorsomedial side of tibia ( Fig. 65 ). Ultimate leg tarsus 1 2.5 times length of tarsus 2; tarsus 1 2–3.3 times longer than pretarsus; pretarsus with pair of short accessory claws.

Discussion. This species is the most morphologically distinct among Indian Digitipes , readily identified by its complete absence of tarsal spurs, the long paramedian sutures on the sternites (nearly complete versus not more than 35% the length of the sternites in other Indian Digitipes ), and by the robust, dorsally-grooved prefemur, femur and tibia of the ultimate legs. Complete paramedian sutures on the sternites are known elsewhere in Digitipes in the type species, D. verdascens Attems.

The two known specimens are both females so no data are at hand with respect to the condition of the femoral process in males. Despite its distinctive character states, its membership in Digitipes is indicated by the support at the nodes in the phylogeny that unite it with Group A of Joshi and Karanth (2012) (posterior probability 0.94 for it grouping with D. coonoorensis and D. indicus ) and that clade as a whole grouping with Groups B and C (posterior probability 1, bootstrap support 100%).

Figures

FIGURES 57 – 62. Digitipes periyarensis n. sp. Holotype CES 091037 (female). 57. Cephalic plate and T 1, dorsal view, scale = 1 mm. 58. Forcipular segment, ventral view, scale = 2 mm. 59. Tooth plates, ventral view, scale = 0.5 mm. 60. Coxopleuron, lateral view, scale = 1 mm. 61. Tergite of ultimate leg-bearing segment, dorsal view, scale = 2 mm. 62. Coxopleuron and sternite of ultimate leg-bearing segment, ventral view, scale = 1 mm.

FIGURES 63 – 67. Digitipes periyarensis n. sp. Holotype CES 091037 (female) except Fig. 63, CES 091038 (female). 63. Ultimate leg prefemur, ventral view, scale = 0.5 mm. 64. Ultimate leg, dorsal view, scale = 1 mm. 65. Ultimate leg femur and tibia, dorsal view, scale = 0.5 mm. 66. TT 18 – 20, dorsal view, scale = 1 mm. 67. Spiracle on segment 3, lateral view, scale = 0.25 mm.