Rhysida trispinosa, (JANGI & DASS, 1984)

Joshi, Jahnavi, Karanth, Praveen K. & Edgecombe, Gregory D., 2020, The out-of-India hypothesis: evidence from an ancient centipede genus, Rhysida (Chilopoda: Scolopendromorpha) from the Oriental Region, and systematics of Indian species, Zoological Journal of the Linnean Society 189, pp. 828-861 : 846-848

RHYSIDA TRISPINOSA ( JANGI & DASS, 1984)

( FIG. 12)

Rhysida lithobioides trispinosus Jangi & Dass, 1984: 48 , figs 93–100. Rhysida lithobioides (CES07102),

Rhysida cf. immarginata (CES07148, CES07202), R h y s i d a s p. 1 (C E S0 7 1 6 5), R h y s i d a l o n g i p e s (CES07262, CES07263), Joshi & Karanth, 2011.

Diagnosis: 20–21 (22) antennal articles. Coxosternal tooth-plates with 4 + 4 teeth, the innermost small. Coxopleural process ~1.5 times length of sternite of ultimate leg-bearing segment, with two apical spines and one subapical spine. Legs 1–18 with two tarsal spurs, legs 19 and 20 with one.

Material

C E S0 7 1 0 2, R a m a n a g a r, R a m a n a g a r a d i s t r i c t, Karnataka; CES07165, Neyyar Wildlife Sanctuary, Thiruvananthapuram district, Kerala; CES07148, CES07149, IISc Campus, Bangalore district, Karnataka; CES08202, Devarayanadurga, Tumkur district, Karnataka; CES08298, Biligirirangana Hills, Chamarajanagar district, Karnataka; CES07262, CES07263, Ranebennur, Haveri district, Karnataka; CES08995, CES08999, CES081000, Thattekad Wildlife Sanctuary, Ernakulam district Kerala; CES091301, CES091302, Achankovil Reserve Forest, Pathanamthitta district, Kerala; CES091387, Javadi hills, Tiruvannamalai district, Tamil Nadu; CES091390, Chinnar Wildlife Sanctuary, Idukki district, Kerala; CES091460, Srisailam, Kurnool district, Andhra Pradesh; CES1517, Palaruvi Reserve Forest, Kollam district, Kerala; CES1545, Kanakpura, Bangalore district, Karnataka; collected by Jahnavi Joshi in July and August, 2008–2009. Locality coordinates in the Supporting Information ( Table S1).

Description: Length ≤ 80 mm. Twenty or 21 antennal articles (one specimen with 22), basal three articles glabrous dorsally and ventrally ( Fig. 12A). Cephalic plate and T1 smooth. Longitudinal median furrow on anterior 10% of cephalic plate. Cephalic plate and T1 red–brown, the following tergites brown, legs pale yellow. Forcipular coxosternal tooth-plates wider than longer with four main teeth, the inner two sharing a common base, the outermost shorter in comparison to the second tooth; base of tooth-plates defined by oblique sutures diverging at 130° ( Fig. 12B, D). Trochanteroprefemoral process bearing two apical teeth and one or two lateral teeth. Tergites with paramedian sutures complete from TT4 to TT8.Tergites not marginated except 21st, incipient margins as far anteriorly as T15. Tergites mostly smooth, sometimes with longitudinal depressions ( Fig. 12G). Paramedian sutures 5–10% length of sternites ( Fig. 12H). Tergite of ultimate leg-bearing segment little wider than long, with parallel lateral margins ( Fig. 12I, J). Sternite of ultimate leg-bearing segment about as wide as long, lateral margins convex, moderately convergent posteriorly; posterior margin gently concave; weak longitudinal median furrow ( Fig. 12C, E). Coxopleuron 1.6 times the length of sternite of ultimate leg-bearing segment; coxopleural process with two apical spines and one subapical spine. Pores dense, with pore-field nearly reaching dorsal margin of coxopleuron; non-porose area on coxopleural process a narrow, short strip towards the tip ( Fig. 12C, E). Ultimate legs long, with prefemur ≤ 5 mm, femur ≤ 4.5 mm, tibia ≤ 3.5 mm, tarsus 1 ≤ 3 mm and tarsus 2 ≤ 2 mm ( Fig. 12K–L); prefemoral spine formula VL2, VM1, DM1; two individuals (CES08999, CES081000) with fewer prefemoral spines, VL1, VM1 ( Fig. 12M, N). Legs 1–18 (17) with two tarsal spurs, legs 19–20 (18) with one. First two pairs of legs with one tibial and femoral spur. Distribution: This species is one of the most widely distributed in peninsular India, occupying a wide range of habitat types, including wet evergreen, moist deciduous, dry deciduous and scrub forests and rocky outcrops.

Remarks: Rhysida trispinosa was described by Jangi & Dass (1984) as a subspecies of R. lithobioides based on a specimen from Pune, Maharashtra (probably from semi-evergreen forests), but including material from other parts of Maharashtra and Tamil Nadu. The type specimens could not be located, but morphological description of the type specimen was compared with all the individuals analysed in the present study. Assignment of our specimens to R. trispinosa emphasizes the eponymous three spines on a moderately long coxopleural process, corresponding numbers of prefemoral spines, and the geographical proximity of some of the new collections and Tamil Nadu records of Jangi & Dass (1984). Specimens studied here agree with the description of R. trispinosa in all respects apart from the type specimen having only the first pair of legs with a tibial spur, whereas almost all of the individuals studied here have the first two pairs of legs with a tibial spur.

In our species delimitation analyses, both GMYC and mPTP retrieve multiple species in R. trispinosa . In GMYC, seven distinct units are identified, of which three are represented by single individuals (CES08217, CES08999 and CES101460) and four with multiple individuals ( Fig. 3). The mPTP retrieves four distinct units, of which again two are represented by single individuals ( Fig. 3). Among the two distinct units, one is represented by 13 individuals from many distinct geographical locations, including CES08999, which is retrieved as a distinct species by GMYC. The second unit is represented by three individuals from northern Western Ghats and also distinct in GMYC. However, morphologically there are no fixed or distinguishing characters observed; therefore, it has been treated as part of R. trispinosa . There is also high (8.5%) within-group variation in COI (corrected p -distance).