Rhysida longipes, Newport, 1845

Popovici, George, Edgecombe, Gregory D. & Hall, Daniel W., 2024, New Chilopoda from the Chagos Archipelago, Journal of Natural History 58 (41 - 44), pp. 1885-1915 : 1898-1899

Rhysida longipes ( Newport, 1845)

( Figure 7 )

Material examined

1 subadult (35 mm), NHMUK015619677 , Chagos Archipelago , Diego Garcia Island, Eclipse Point, April 1971, leg. A.M. Hutson; 1 juvenile (16 mm), NHMUK015558200 , from Diego Garcia , site O4 BM2 , July 2022, leg. W. Rabitsch, Malaise slam trap; 1 juvenile (15 mm), NHMUK015619672 , Diego Garcia , Downtown, 7.263°S, 72.374°E, 26 June 2022, leg. W. Rabitsch, suction sampler; 1 adult, SMF, Diego Garcia, Tschagos Archipel, 1899.

Description

Habitus. Proximal half of antenna pale yellow, distal half pale blue. Cephalic plate, tergites 1–2 and tergite of ultimate leg-bearing segment yellow-brown, remaining tergites pale blue.

Head and forcipular segment. Antenna with 18 articles, the first four glabrous dorsally, first three glabrous ventrally. Coxosternal tooth-plates with four teeth grouped into medial and outer pairs ( Figure 7 (A)). Medial pair with innermost teeth greatly reduced. Trochanteroprefemoral process with four distinct teeth.

Trunk. Paramedian sutures beginning on tergite four or five. No evident paramedian sutures on sternites. Tergite margination incomplete on tergites 7 or 8, complete from tergites 8 or 9.

Walking legs. Femoral spur present on leg pair 1 ( Figure 7 (C)). Tibial spur present on leg pairs 1–2, 3 or 4, two tarsal spurs present on leg pairs 1–5, 6 or 7, one tarsal spur present on leg pairs 6/8–19 ( Figure 7 (D)); tarsal spurs lacking on legs 20 and 21.

Ultimate leg-bearing segment ( Figure 7 (B)). Sternite of ultimate leg-bearing segment with straight lateral margins converging posteriorly; posterior margin nearly straight. Coxopleural process moderately long, with 2 apical spines (1 on one side of specimen NHMUK015558200), 1 subapical and 1 lateral spine; pore field terminates at base of coxopleural process in juveniles ( Figure 7 (B)). Prefemur with 3 ventrolateral, 2 or 3 ventromedian, 0 or 1 median, and 3 dorsolateral spines.

Remarks. The morphology of the specimens agrees with the description of R. longipes from Eagle Island in the Chagos Archipelago ( Lewis and Cole 2007). Similarities in the pattern of glabrous antennal articles between specimens collected in Sri Lanka and those from the Chagos (ie four articles glabrous dorsally vs the usual three) were given as a potential indication of introduction through human activity. The wide distribution of R. longipes throughout Southern and Southeastern Asia is indicative of its dispersal capability; however, as the similarity between the fauna of Diego Garcia (Chagos) and Sri Lanka extends to centipedes not known to be associated with anthropochoric dispersal (see Australobius chagosensis ), the case for natural colonisation of the archipelago by R. longipes cannot be excluded.

Figures

Figure 7. Rhysida longipes Newport, 1845. NHMUK015619672. (A) Anterior margin of forcipular coxosternite and internal margin of left forcipule, ventral view. (B) Ultimate leg-bearing segment and postpedal segments, ventral view. (C) Leg 1, lateral view, showing tibial spur and tarsal spurs. (D) Leg 7, lateral view.