Rhysida H.C. Wood, 1862

Schileyko, Arkady A., Vahtera, Varpu & Edgecombe, Gregory D., 2020, An overview of the extant genera and subgenera of the order Scolopendromorpha (Chilopoda): a new identification key and updated diagnoses, Zootaxa 4825 (1), pp. 1-64 : 50

(!) Rhysida H.C. Wood, 1862

Figs 106–109

Type species. Branchiostoma lithobioides Newport, 1845 (by subsequent designation of Attems 1930) .

Diagnosis. Median tooth of labrum well developed. Forcipular tooth-plates present, trochantero-prefemur with well-developed process ( Fig. 106 ). Tergites never with longitudinal keels (except for median one in a few species). Sternites with incomplete paramedian sutures (in some species much shortened, sometimes also with median and lateral depressions of various sizes/shapes. LBS 7 with spiracles, the latter with atrium ( Fig. 108 ). Legs with tarsal spur(s), legs 1 without prefemoral spur. Coxopleural process ( Fig. 109 ) ranging from short to very long and much enlarged (figs 4F and 9F in Siriwut et al. 2018, respectively), with spines (at least with apical ones). Prefemur of the ultimate leg with spines ( Fig. 107 ), more rarely (for example in R. celeris ) without them; pronounced corner spine absent (in some species 1(2) spines at its place, Fig. 107 ). Ultimate pretarsus well-developed, with accessory spines.

Number of species. 36 ( Joshi et al. 2020).

Sexual dimorphism. Unknown.

Remarks. Treated as a genus in Edgecombe & Bonato (2011: 402), Vahtera et al. (2012a: 7, 2012b: 238, 2013: 578), Chagas-Jr (2013: 17), Schileyko (2014: 182), Schileyko & Stoev (2016: 255), Siriwut et al. (2018: 1005); Joshi et al. (2020); the latter work is the most recent account on this genus (see also Remarks to Alluropus below). In 2013 Chagas-Jr synonymized seven species of Rhysida (namely R. caripensis , R. guayanica , R. maritima , R. monaguensis , R. neoesparanta , R. porlamarensis and R. sucupaensis ) described by González-Sponga (2002) to R. celeris . Five new species were described from India by Joshi et al. (2020).

We re-investigated a dozen specimens of R. celeris from Peru (Rc 6685) and Brazil (Rc 7272), R. immarginata (Porat, 1876) from Papua New Guinea (Rc 7091), R. longipes (Newport, 1845) from Cambodia (Rc 7003) and Peru (Rc 6683), R. lithobioides (Newport, 1845) from Sumatra (Rc 7232). All the studied specimens showed a total absence of both a corner spine of the ultimate legs ( Fig. 107 ) and a prefemoral spur on legs 1.

Figures

FIGURES 102–107. Ethmostigmus rubripes spinosus (Newport, 1845); Juv. Rc 7174 102 forcipular segment ventrally; Ethmostigmus rubripes platycephalus (Newport, 1845); Ad. Rc 7514 103 left pleuron of LBS 3 laterally; Ad. Rc 7513 104 LBS 21 ventrally; Sad. СDT 105 coxopleural processes + prefemora of ultimate legs ventrally; Rhysida longipes (Newport, 1845); Ad. Rc 6683 106 anterior margin of forcipular coxosternite ventrally 107 coxopleural processes, legs 20 + ultimate legs laterally; (ap)—apical spine, (bs)—basal suture of forcipular tooth-plate, (cp)—coxopleural process, (csp)—corner spine of ultimate prefemur, (cx)—coxopleuron, (im)—intersclerite membrane, (lc)—lateral spines of coxopleural process, (pf)—ultimate prefemur, (pr)—trochantero-prefemoral process, (pts)—ultimate pretarsus, (rpf)—abnormally small (regenerated) right ultimate prefemur, (rpr)—rudiment of trochantero-prefemoral process, (s)—open spiracle without atrium, (scs)— spine at place of corner spine of ultimate prefemur, (su)—spines of ultimate prefemur, (t1)—ultimate tarsus 1, (tp)—forcipular tooth-plates, (ust)—ultimate sternite.

FIGURES 108–112. Rhysida longipes (Newport, 1845); Ad. Rc 7003 108 left pleuron of LBS 3 laterally; Ad, Rc 7003 109 LBS 21 ventrally; Alluropus calcaratus (Pocock, 1891) (photos by Warut Siriwut); Ad. male CUMZ 00470 110 LBS 20, 21 + ultimate legs dorso-laterally; Ad. female CUMZ 00501 111 head, forcipular segment and LBS 1, 2 ventrally; Ad. female CUMZ 00501 112 LBS 20, 21 + prefemora of ultimate legs ventrally; (20)—leg 20, (ap)—apical + ventral subapical spines of coxopleural process, (cp)—coxopleural process, (csp)—corner spine of ultimate prefemur, (dd)—male’s dorsodistal projection of ultimate tarsus 1, (im)—intersclerite membrane, (lc)—lateral spine of coxopleural process, (pfs)—prefemoral spur of leg 1, (pr)—trochantero-prefemural process, (pts)—pretarsus, (s)—spiracle, (sh)— spiracle hump, (su)—spines of ultimate prefemur, (t1)—male’s enlarged ultimate tarsus 1, (t2)—male’s slim ultimate tarsus 2, (tp)—forcipular tooth-plates, (ust)—ultimate sternite, (ut)—ultimate tergite.