Xystodesmus yamamiensis Masuda 2001
Creators: name: Korsós, Zoltán
name: Nakamura, Yasuyuki
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Diplopoda
Polydesmida
Xystodesmidae
Xystodesmus
Xystodesmus yamamiensis

description: Xystodesmus yamamiensis Masuda, 2001
Fig. 15 B
Material examined.
Holotype male (NSMT -My.294), and paratype male (NSMT -My.295), Aichi Pref., Chita County, Minamichita Town, Yamami, 5 April 1998, leg. K. Masuda.
Descriptive notes.
The original description and illustrations lack some important details, thus after the re-examination of the holotype, we present here an additional drawing of the male gonopod (Fig. 15 B). Coxa stout, as wide as long, with a strong apophyseal process (ca) and a large macroseta (ms). Prefemur and acropodite slightly twisted, prefemoral process (pfp) ~ ¾ of length of acropodite, those of two gonopods crossing each other in situ. Prostatic groove runs along lateral side of acropodite (a) and ends on distal part of lower branch of bifurcated tip.
Remarks.
Interestingly, the gonopods have a general similarity to Riukiaria neptuna (Pocock, 1895) (Korsós et al. 2011), as the end of acropodite is ramified: two branches in X. yamamiensis, three in R. neptuna (see Pocock 1895; Hoffman 1949). However, the body size (19–24 mm) and especially the colour of X. yamamiensis (“ Keels have a red spot in roughly in the middle. ” Masuda 2001: 635) clearly indicate that this is a species of Xystodesmus.
Unidentified Xystodesmus female 1
Fig. 16 G
Material examined. • 6 females, Japan, Central Ryukyus, Okinawa Pref., Okinawa Group, Tokashiki-jima Isl., National Okinawa Youth Fellowship Center, mixed forest, 26°12'40.7"N, 127°21'46.4"E, 200 m, 9–10 April 2010, leg. Z. Korsós (No. 183) (RUMF); • 2 females, Japan, Central Ryukyus, Okinawa Pref., Okinawa Group, Tokashiki-jima Isl., Tokashiki, Otani forest road, mixed forest, 26°12'45.3"N, 127°21'26.3"E, 18 m, 10 April 2010, leg. Z. Korsós (HNHM diplo-04552); • 2 females, Japan, Central Ryukyus, Okinawa Pref., Okinawa Group, Tokashiki-jima Isl., National Okinawa Youth Fellowship Center, outside the fence, mixed forest, 26°12'44"N, 127°21'50"E, 215 m, 21 October 2010, leg. Z. Korsós (No. 266) (RUMF)
Colour of living specimens (Fig. 16 G). Body uniformly dark brown, posterior edge of metaterga darker; paranota from 5 th segment onward light, yellowish orange; head brown, antennae, legs, and underside whitish.
Remark. Probably the same species as the one occurring on Aka-jima Isl., i. e., X. keramae sp. nov. (Fig. 16 B).
Unidentified Xystodesmus female 2
Fig. 16 H
Material examined. • 1 female, Japan, Central Ryukyus, Amami Group, Tokuno-shima Island, Kametsu, near the pass between Mt. Inokawa-dake and Mt. Hage-dake, 27°45'38.4"N, 128°58'53.7"E, Castanopsis sieboldii forest, 4 February 2012, leg. Y. Nakamura (HNHM diplo-04553)
Colour of living specimens (Fig. 16 H). Body uniformly dark greyish brown, median and posterior part of metaterga darker; all paranota including collum with light, yellowish spots; head and epiproct greyish brown; antennae, legs, and underside whitish.
Remark. Up to now this is the only Xystodesmus specimen from Tokuno-shima Island and probably represent a different species. However, without knowing the male it would be premature to assign it to any category.
description: Published as part of Korsós, Zoltán & Nakamura, Yasuyuki, 2025, Review of the millipede genus Xystodesmus (Diplopoda, Polydesmida), with seven new species from the southwestern part of Japan, pp. 191-232 in ZooKeys 1231 on pages 191-232, DOI: 10.3897/zookeys.1231.141443