Digitipes barnabasi Jangi and Dass, 1984

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 : 102-105

Digitipes barnabasi Jangi and Dass, 1984

( Figs 1–12 )

Digitipes barnabasi Jangi and Dass, 1984: 44 , figs 73–79.

Digitipes barnabasi . Yadav 1993: 171; Sureshan et al. 2006: 2287. Digitipes putative species 7. Joshi and Karanth, 2012: figs 2, 3, 7. Digitipes putative species 8. Joshi and Karanth, 2012: figs 2, 3, 7.

Diagnosis. Digitipes with basal two antennal articles glabrous dorsally and ventrally. Flat median ridge consistently present from T3 to 5–20, irregular rugose ridges at least weakly distinct on lateral parts of tergites in posterior half of trunk; five continuous, tuberculate longitudinal keels from TT6–9 variably present. Coxopleural process relatively short, lateral spine consistently present; pore field extending close to dorsal margin of coxopleuron. Dorsomedial process on ultimate leg femur of male relatively short.

Material examined. 12 specimens of Digitipes putative species 8 ( D. barnabasi of Joshi and Karanth, 2012), including CES 091348, CES 091353 and CES 091355 from near type locality, and four of Digitipes putative species 7; CES registration numbers in Joshi and Karanth (2012: fig. 2, Table S1). The examined individuals were collected across the evergreen forests of the Western Ghats encompassing 8°–19° N latitude and 100–1800 m elevation (distribution maps in Joshi and Karanth 2012: fig. 7c); all leg. J. Joshi, 2007–2010.

Description. Length to 66 mm. 17 antennal articles; basal two (three in one individual) articles glabrous both dorsally ( Fig. 1 ) and ventrally. Cephalic plate and tergites punctate. Longitudinal median furrow on anterior 20% of cephalic plate, occasionally slightly longer; pair of short, medially converging furrows on posterior part of cephalic plate at least faint, in some specimens well defined.

Cephalic plate and T1 red-brown, the following tergites more deeply chestnut brown, variably with some blue pigmentation near the lateral margin; legs pale brown, often with a light purple tinge.

Forcipular coxosternal tooth plates slightly longer than wide ( Fig. 2 ), with four main teeth, the inner two grouped together, sometimes partially fused, outer two acute, the outermost smaller than the other three ( Fig. 3 ); single strong seta posterior to lateral edge of second tooth; base of tooth plates defined by oblique sutures diverging at 130–140°. Trochanteroprefemoral process with two inner teeth and apical tooth.

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

Tergites with paramedian sutures complete from TT5 to 7. Tergites fully marginate starting from TT5 to 8, incipient margins as far anteriorly as T2. Tergites mostly smooth apart from longitudinal median ridge beginning from TT3 to 5 ( Fig. 11 ) and at least faint (variably strong), irregular rugose ridges on lateral part of tergites in posterior half of trunk; a few individuals with strong ridges and keels/tubercles ( Fig. 10 ); three keels between paramedian sutures, one immediately lateral to them, those more laterally poorly-defined, anastomosing. Paramedian sutures 10–20% length of sternites in mid body region.

First four to at least 14 (usually 4–7) pairs of legs with two tarsal spurs, the subsequent to 20 with one. A tibial and a femoral spur on leg 1 only.

Tergite of ultimate leg-bearing segment with faintly convex, nearly parallel lateral margins; posterior margin variably sinuous, rounded posteromedially ( Fig. 5 ). Sternite of ultimate leg-bearing segment relatively elongate trapezoidal, with sides converging posteriorly, nearly straight, posterior margin gently to moderately concave ( Fig. 6 ); weak trace of an incomplete longitudinal median furrow variably present.

Coxopleural process relatively short, stoutly conical in ventral view with marked inflection from posterolateral margin of coxopleuron, with two apical spines, one lateral spine ( Fig. 6 ). Pores dense, variable in size, nearly reaching dorsal margin of coxopleuron ( Figs 4 , 12 ); non-porose area on process narrow, not extending as far as posterior margin of sternite of ultimate leg-bearing segment, variably less than half length to that margin. Ultimate leg prefemur with width at distal end about 25% its length; prefemoral spines at most moderately large: VL 3 (2 in one individual), VM 2, DM 0 or 1 ( Fig. 7 ). Distomedial process in males bluntly conical, extending only about as far as distal end of femur on its dorsal side ( Fig. 8 ); shallow groove along most of length of femur on its medial surface ( Fig. 9 ). Ultimate leg tarsus 1 1.8–2.2 times length of tarsus 2; tarsus 1 3–4.8 times longer than pretarsus; pretarsus with pair of accessory claws.

Discussion. PS7 of Joshi and Karanth (2012) was represented by four individuals (three of them immature) that shared all diagnostic characters with D. barnabasi , including 17 antennal articles of which two are glabrous on both the dorsal and ventral sides, the coxopleural process with a similar shape and the pore field approximating the dorsal margin of the coxopleuron, leg 20 bearing a tarsal spur, a longitudinal median ridge on the tergites, and irregular ridges on the lateral part of the tergites. In the molecular phylogeny based on mtDNA data, the monophyly of PS7 was not supported. Both PS7 and PS8 have a higher frequency of specimens with two tarsal spurs on more than just the anterior three or four leg pairs than in other Indian Digitipes , two spurs being present at least as far as leg 7 in both putative species. Because we have not identified any consistent diagnostic morphological characters to distinguish PS7 from PS8, together with the small sample of the former, we have referred both to a single species, D. barnabasi . Geographically these two putative units show very distinct distributions, with PS7 occurring in the southern and central parts of the Western Ghats and PS8 being restricted to the northern parts of the Western Ghats. Henceforth, D. barnabasi becomes one of the most widely distributed Digitipes species of the Western Ghats showing strong population structure.

In the synonymy above we include a specimen from the Kannur district, Kerala, assigned to the species by Surehan et al. (2006); a photograph of the specimen provided by D. Balan shows characters corresponding to D. barnabasi as understood here. A record from the Pune district, Maharashtra, by Yadav (1993a) is within the geographic distribution of D. barnabasi and is accordingly listed above, but we have not been able to access the specimens.

Figures

FIGURES 1 – 6. Digitipes barnabasi Jangi and Dass, 1984. CES 091355 (female) except Figs 1, 4, CES 091353 (female). 1. Cephalic plate and T 1, dorsal view, scale = 0.5 mm. 2. Forcipular segment, ventral view, scale = 1 mm. 3. Tooth plates, ventral view, scale = 0.5 mm. 4. Coxopleuron, lateral view, scale = 0.5 mm. 5. Tergite of ultimate leg-bearing segment, dorsal view, scale = 1 mm. 6. Coxopleuron and sternite of ultimate leg-bearing segment, ventral view, scale = 2 mm.

FIGURES 7 – 12. Digitipes barnabasi Jangi and Dass, 1984. 7. Ultimate leg prefemur, ventral view, CES 091355 (female), scale = 1 mm, 8. Ultimate leg femur, dorsal view, CES 091033 (male), scale = 1 mm. 9. Ultimate leg femur, medial view, CES 091033, scale = 1 mm. 10. TT 18 – 20, dorsal view, CES 091033, scale = 1 mm. 11. TT 18 – 20, dorsal view, CES 091355, scale = 1 mm. 12. Coxopleuron, lateral view, CES 091017, scale = 0.5 mm.