Digitipes Attems, 1930a : 167

Siriwut, Warut, Edgecombe, Gregory D., Sutcharit, Chirasak, Tongkerd, Piyoros & Panha, Somsak, 2015, First record of the African-Indian centipede genus Digitipes Attems, 1930 (Scolopendromorpha: Otostigminae) from Myanmar, and the systematic position of a new species based on molecular phylogenetics, Zootaxa 3931 (1), pp. 71-87 : 75

Digitipes Attems, 1930a: 167 ; 1930b: 291.

Type species. Digitipes verdascens Attems, 1930 , by monotypy.

Composite description. 16–18 antennal articles, 2.5–3.5 articles glabrous dorsally. Cephalic plate with anterior median sulcus that may be posteriorly bifurcated. Forcipular coxosternite without median suture. Tooth-plate wider than long, with four teeth on each side separated into two groups of two lateral and two median teeth. Trochanteroprefemoral process bearing one apical tooth and two or three inner teeth. Tergite 1 overlapping cephalic plate, without transverse sulcus or suture. Tergites with or without keels; oblique suture starting from T4 or 5 to T19. Paramedian sutures complete from at least TT 7 to 20. Tergite margination usually starting at least from T5; exceptionally only tergite of ultimate leg-bearing segment marginated. Tergite of ultimate leg-bearing segment with convex lateral margins. Sternites with small punctae, occasionally with median sulcus; depressionlike pits on posterior part of sternite. Paramedian sutures at least 10% length of sternite, nearly complete in a few species. Sternite of ultimate leg-bearing segment trapezoidal, with sides converging posteriorly. Coxopleural process short to moderately long, with two apical spines, one lateral spine or absent, dorsal spine absent. Pore-field on lateral part of coxopleuron extending to dorsal margin or terminating beneath that margin. Spine formula on ultimate leg prefemur: VL 1–4 or absent, VM 1–5 or absent, M 0–1 and DM 1–2 or absent. Locomotory legs usually with two tarsal spurs on at least legs 1–3, usually one tarsal spur on legs 4–20. Tibial and femoral spur on leg 1 or absent. Male with blunt conical distal process on ultimate leg femur; shallow longitudinal furrow along medial surface of femur terminating at the process. Spiracles rounded or oval, on segments 3, 5, 8, 10, 12, 14, 16, 18 and 20.

Remarks. Digitipes is similar to the widespread, mostly tropical genus Otostigmus in most respects, but three distinguishing characters were proposed ( Attems 1930b). Most noteworthy is the distal process on the ultimate leg femur that is present in males of Digitipes but is absent in Otostigmus . Attems also considered the absence of a large spine on article 2 of the telopodite of the second maxilla and an absence of accessary spines on the second maxillary pretarsus as diagnostic of Digitipes . The lack of a spine on article 2 has proven to be unreliable because it is on the one hand present in all Indian species of Digitipes ( Joshi and Edgecombe 2013) and on the other hand is likewise absent in various species of the related genus Otostigmus ( Lewis 2004, Chagas-Júnior et al. 2007). In some species of Otostigmus it is even subject to geographic variability between conspecific populations ( Schileyko 1995; Lewis 2004). In the case of pretarsal accessory spines on the second maxilla, an absence in at least two African species ( D. verdascens and D. reichardti (Kraepelin, 1903)) is not matched by Digitipes species from India, where they are demonstrably present ( Joshi and Edgecombe 2013). The most reliable morphological autapomorphy of Digitipes remains the presence of the femoral process in the male, coupled with a longitudinal furrow that extends along the medial surface of the femur and terminates at the process in male. These characters remain unknown in D. periyarensis Joshi and Edgecombe, 2013 and D. krausi Dobroruka, 1968 , for which males have not been documented. Immature and limited material of unsexed specimens may be subject to misidentification at both the genus and species levels.

Currently the genus comprises three species from central Africa and six species from western India ( Attems 1930a, b; Jangi and Dass 1984; Joshi and Edgecombe 2013). Molecular distances ( Table 2) and the composite data of morphological characters for all members (Table 3) suggest that the number of glabrous antennal articles, the posterior bifurcation of a median sulcus on the cephalic plate, the extent of paramedian sutures on the sternites, as well as the presence or absence of a lateral spine on the coxopleural process are taxonomically informative and useful for species discrimination. Our key has been constructed based on a combination of the taxonomic keys to species by Jangi and Dass (1984) and Joshi and Edgecombe (2013), together with additional taxonomic characters.