Eudigraphis takakuwai ( Miyosi, 1947 )

Karasawa, Shigenori, Kawano, Keisuke, Fukaya, Shin-ichi & Tsurusaki, Nobuo, 2020, Upgrading of Three Subspecies of Eudigraphis takakuwai to the Species Rank (Diplopoda: Penicillata: Polyxenida: Polyxenidae), Species Diversity 25, pp. 89-102 : 93-98

Eudigraphis takakuwai ( Miyosi, 1947)

[Japanese name: Usuaka-fusayasude]

( Figs 1 , 4B , 5A, B , 6 A–C)

Monographis kraepelini (not of Attens, 1907): Takakuwa and Takashima 1942: 123, an unnumbered figure on p. 123; Takakuwa 1954: 18, fig. 18; Omine 1965: table 1.

Monographis takakuwai Miyosi, 1947: 2 , figs 1, 2 [in part; type locality: Kyaku, Mikame-cho (Now a part of Seiyo City), Nishi-uwa-gun, Ehime Prefecture, Shikoku, Japan; type specimens seem to be lost].

Monographis takakuwai takakuwai Miyosi, 1947: 2 , figs 1, 2; Takashima and Haga 1950: 22, fig. 1; Miyosi,1959: 58, pl. 1, fig. 1; Miyosi 1965: 741, one text-figure; Ishii 1977: 35; Miyosi 1979: 478, one text-figure; Ishii and Yamaoka 1982: 767; Ishii and Yamaoka 1983: 41; Ishii 1983: 45.

Eudigraphis japonica Silvestri, 1948: 219 (type locality: Nagoya).

Eudigraphis takakuwai takakuwai: Murakami 1972: 85 , fig. 4A; Ishii 1988: 957, figs 8, 9; Matsumoto and Gamo 1992: 54, figs 2–7; Murakami 1993: 97; Kuwahara 1993: 15; Ogata 1997: 2, fig. 1 (photo); Nguyen Duy-Jacquemin and Geoffroy 2003: 99; Ichisawa et al. 2012: 13; Kawano 2017: 16, figs 1, 2.

Eudigraphis takakuwai: Haga 1952: 15 (in part); Nguyen Duy-Jacquemin and Condé 1967: 80 (in part); Minato 1968: 20 (in part); Minato 1971: 46 (in part); Tanabe 1992: 65; Ishii and Tamura 1995: 233; Ishii 1997: 257; Shinohara and Tanabe 1999: fig. 1 on p. 667; Tsurusaki 1999: 61; Ishii 1999: 212; Ishii 2000: 107; Takano 2001: 222; Ishii 2002: 298; Tsurusaki 2002: 151; Tsurusaki 2012: 285; Shinohara et al. 2015: fig. 1 on p. 964; Minagoshi 2017: 51, 2 photos.

Diagnosis. Body 3.8–4.5 mm long excluding caudal bundle with no difference between sexes. Ground color of body pale yellowish brown, including head, in dorsal view. Each segment of body laterally tinted with dark brown, though the markings easily fade away in preserved specimens in ethanol. Mandible with 7 molar processes and 9 molar combs (for the details in mandible structure, see Ishii 1988).

Brief description [based on specimens from Suwazaki Coast, a locality closely located to the type locality (Kyaku) of the species in Mikame-cho, Seiyo City, Ehime

Prefecture]. Body length without caudal bundle (males) 3.8–4.0 mm (n =2, mean 3.9 mm).

Coloration. Head and tergites lighter yellowish brown laterally tinted with brown.

Body with 10 segments, 9 pleural projections and a telson, 13 pairs of legs ( Fig. 5A, B ).

Head with 8 ocelli each side. Head with anterior rows of ca. 30 trichomes arranged in 2 closely positioned rows ( Fig. 6C ) and a middle rows of ca. 10 trichomes and a posterior row with a few scattered trichomes ( Fig. 6C ).

The antennae with 8 articles as shown in Fig. 6A, B ). Article VI with 3 thick basiconic sensilla (T) ventrodistally of equal length; article VII ventrodistally with 2 thick basiconic sensilla ( Fig. 6B ). The presence of conical and setiform sensilla were unable to be determined.

Clypeo-labrum with 10 setae along posterior margin; anterior margin of labrum smooth, only slightly sinuated ( Fig. 6A ). Gnathochilarium with slender lateral palp with 12 cylindrical sensilla, medial palp with ca. 10 sensilla.

Leg 1 without trochanter and tarsus 1. Femur distoventrally with a biarticulated seta with a tall cylindrical funicle

( Fig. 6A ). Leg 2 femur with similar biarticulated seta. Postfemur and tibia ventrodistally with a similar biarticulated seta.

Material examined. CHIBA PREFECTURE. Minamiboso City, Chikura-machi, Hedate , Inari Shrine (34.99120833, 139.8250694) (2 juv., 20 June 2019, T. Suzuki) ; Tateyama City, Fujimi, Okinoshima island (34.99120833, 139.8250694, 10 juv., 20 June 2019, T. Suzuki). —— TOKYO METROPOLIS. Shinjuku Ward, Toyama Park ( Hakoneyama ) (35.705781, 139.713364), 20 m, under bark of trunks of Zelkova serrata (6 spms., 99% EtOH, 17 October 2017, SF). —— SHIZUOKA PREFECTURE. Kamo-gun, Minami-izu-cho, Irozaki, Hachiman Shrine (34.61388889, 138.85), 40 m (2 juv., 29 April 2008, NT) ; Sunto-gun, Shimizu-cho, Tokura, Honjoyama Park (3 spms., 80%, then 99% EtOH, and 2 spms., 80% EtOH, 2 January 2018, Y. Obae). —— SHIGA PREFECTURE. Nagahama City: Oyori-cho, Iwasakiyama , Norikura Tumulus (35.431263, 136.314631), 150 m, Quercus serrata forest (15 juv., 30 October 2019, NT) ; Kohoku-cho, Odani-jo Castle (35.455330, 136.276817), 230 m alt., Deciduous broad-leaved forest (8 juv., 25 October 2018, NT) ; Nishi- Azai-cho, Tsukide, Oku-Biwako Parkway (35.499430, 136.160136), 210 m, Cryptomeria japonica forest (1 adult, 20 juv., 30 October 2019, NT). Omi-hachiman City, Aduchi Castle Ruins (35.153276, 136.138340), 90 m (1 juv., 29 October 2019, NT). —— TOTTORI PREFECTURE. Tottori City: Fukube-cho, Sakadani Shrine, 40–70 m, evergreen broad-leaved forest, (1 juv., 99% EtOH, 18 January 2012, NT) ; Kokufu-cho, Ube Shrine, 27–32 m (1 adult and 1 juv., 1 June 1999, TM) ; Mt. Gentayu, 35 m (2 spms, 21 September 1998, TM) ; Mt. Gentayu, Ochidani, 40 m, Abies firma and Quercus acuta forest, (1 spm., 99% EtOH, 18 April 2011, NT) ; Tottori City Historical Museum, 30 m, Abies firma and Cryptomeria japonica forest (2 spms., 99% EtOH, 6 December 2011, NT) ; Mt. Kyusho, 70–220 m, soil litter (7 spms., 14 May 1998 ; 2 spms., 27 May 1998, TM ; 1 spm., 25 June 1998 ; 5 spms., 24 July 1998 ; 18 adults and 36 juv., 23 August 1998 ; 1 juv., 9 October 1998 ; 1 adult and 9 juv., 2 November 1998; all TM) ; Ue-machi, Inari Shrine, 30 m (3 juv., 9 July 1998, TM) ; Yudokoro-cho, Heiwa-notô Pagoda, 30–110 m, soil litter (5 spms., 28 May 1998 ; 3 spms., 18 June 1998 ; 8 spms., 9 July 1998 ; 3 spms., 1 August 1998 ; 2 juv., 11 August 1998 ; 15 adults and 76 juv., 26 August 1998 ; 2 adults and 1 juv., 10 September 1998 ; 10 adults and 18 juv., 5 October 1998 ; 9 juv., 5 November 1998; all TM) ; Hamasaka, Hamasaka Shrine, 23–40 m, soil litter (1 spm., 4 June 1998 ; 1 spm., 12 August 1998 ; 1 juv., 12 August 1998 ; 1 adult and 2 juv., 14 September 1998; all TM) ; Koyama, Koyama Shrine, 13–24 m, (1 spm., 8 June 1998. TM ; 6 adults and 4 juv., 22 August 1998, TM ; 2 spms., 5 December 2011, NT) ; Koyama , Urayama Hill , Koyama Shrine (35.513090, 134.178836), 20–30 m, soil litter (12 spms., 99% EtOH, 26 April 2011, NT ; 2 adults and 1 juv., 99% EtOH, 7 January 2018, NT) ; Koyama , Tenjinyama Hill , 5 m, soil litter (1 spm., 16 August 1998 ; 6 juv., 5 December 1998 ; 2 juv., 13 August 1999 ; 1 male, 23 December 1999: all TM) ; Fuse, Hie Shrine, 2–20 m (1 male and 1 juv., 26 August 1998 ; 1 juv., 5 October 1998 ; 1 juv., 2 June 1999: all TM) ; Takazumi, Kitano Shrine, 30 m (1 spm., 5 September 1998, TM). —— HIROSHIMA PREFECTURE. Hiroshima City, Mt. Gosaso-zan (34.422470, 132.547088), 670 m, under barks of Pinus densiflora (12 spms., 11 December 1977, NT). —— YAMAGUCHI PREFECTURE. Shimonoseki City: Oogawara Beach , (4 spms., 99% EtOH, 25 September 2017, Makiko Matsuda) ; Toyoura-cho, Waita (1 female, 31 August 2017, KK). —— EHIME PREFECTURE. Imabari City, Umashima Shrine, Umashima island (1 spm., 25 November 2000, Haruko Ishikawa) ; Matsuyama City: Hojo, Kami-Namba , Eryo Shrine, 40 m (1 spm., 7 February 2010, NT) ; Takahama, Shiraishi-no-hana Point (3 spms., 23 September 2012, Kazuo Ishikawa) ; Matsuyama Castle, Soil litter in Castanopsis cuspidata forest, 50 m (ca. 30 spms., 3 January 1994, NT) ; Takai-cho, Takai-Hachiman Shrine (1 juv., 24 April 2000, NT). Seiyo City, Mikame-cho, Kyaku (33.388036, 132.429757 ; 2 females and 3 juv., 24 March 2019, NT) ; Mikame-cho, Suzaki Coast (33.366568, 132.390543), forest litter of Quercus phillyraeoides forest (3 males, 2 females and 3 juv., 24 March 2019, NT). —— KOCHI PREF. Tosa-shimizu City, Ashizuri Cape (3 spms., 80%, then 99% EtOH, 23 December 2017, Shogo Makita). —— OKINAWA PREFECTURE. Nakagusuku-son, Yoshinoura Park (26.259283, 127.792886), leaf litter in tree hole of Ficus superba var. japonica (5 spms., 99% EtOH, 12 March 2018, SK) .

Distribution. Honshu (west from Tokyo), Shikoku, Kyushu, the Ryukyu Islands (Okinawa-jima, Kume-jima, Izena-jima and Ishigaki-jima islands: Omine 1965), and Izu Islands (Miyake-jima island: Ishii and Yamaoka 1982).

Minato (1973) reported this species without mentioning subspecies from Otoko-jima island of the Danjo Islands (Nagasaki Prefecture). Likewise, Minato (1969) reported occurrence of Monographis takakuwai s. lat. from Shimokoshiki-jima island and Yamato-hama beach in Amami-Oshima island (Kagoshima Prefecture). Considering the localities are directly facing the ocean, it might be possible that these records are not of E. takakuwai s. str. but of E. nigricans . Thus, these localities are not shown in Fig. 1 .

Habitat. This species is usually found from soil litter on the forest floor, though the species can also often be found from crevices under bark of trunks of trees such as Ginkgo biloba (Ginkgoaceae) , Pinus densiflora (Pinaceae) , Zelkova serrate (Ulmaceae) , Aphananthe aspera (Cannabaceae) . Takashima and Haga (1950) suggested that this species usually migrates to the trunks of trees from soil litter on the forest floor in winter. On the other hand, Ishii (1977) showed that this species inhabits crevices of tree trunks of Zelkova serrata all year round. The species has been abundantly recorded also from arboreal nests of some species of ants, such as Crematogaster vagula Wheeler, 1928 , Tapinoma indicum Forel, 1895 , Camponotus nipponicus Wheeler, 1928 ( Ishii and Yamaoka 1982, 1983).

Ecology. This species is univoltine and overwinters as adults and juveniles, though both adults and juveniles of various stages can also be seen all year round (see collecting records for several populations made in Tottori City throughout the year). Eggs laid can be seen from July to October according to observations for a population in Ibaraki Prefecture ( Ishii 1997). Eggs are 0.4 mm in long and 0.25 mm in short diameters ( Ishii 1977). The number of eggs per batch is ca. 33 on average ( Ishii 1997). Each egg batch is covered with body hairs of the female who laid the batch ( Murakami 1972). Ishii (1997) reported that the digestive tract was filled with minute fragments of litter.

Remarks. Sierwald and Spelda (2018) placed E. xishuangbanna , described from Yunnan Province in southwestern China, under a junior synonym of E. t. takakuwai citing Nguyen Duy-Jacquemin and Geoffroy (2003) as the source of synonymy. However, no synonymization can be found in the article by Nguyen Duy-Jacquemin and Geoffroy (2003). Thus, E. xishuangbanna should be treated as a different species from E. takakuwai , though we have at present no idea of the relationship between the two species.

This species was first recorded from Japan as Monographis kraepelini Attems, 1907 on the basis of five specimens collected from Shuri (Naha City) of Okinawa-jima island ( Takakuwa and Takashima 1942; Takakuwa 1954). Omine (1965) also listed M. kraepelini in the table enumerating distributional records in the Ryukyu Islands (the species is marked on the following islands: Ishigaki-jima, Kume-jima, Ie-jima, and Izena-jima). However, Ishii (1988) concluded that these records are misidentification of E. takakuwai s. str., based on the experience obtained through his extensive surveys in the Ryukyu Islands.

Most of the type specimens of millipedes described by Dr. Yasunori Miyosi had been probably stored in his personal collections (see Takashima 1955). However, one of the author, NT, was not able to find the type specimens of E. t. takakuwai and E. t. nigricans in Dr. Miyosi’s collection stored in the warehouse in his home when NT visited his home just after his passing away in 1995.

Figures

Fig. 1. Distribution of three species of Eudigraphis with source of samples used for molecular phylogenetic analysis. Localities of samples are shown in brackets. Sample numbers correspond to those in Table 1 and Figs 2, 3. Literature and new records were also incorporated.

Fig. 4. Typical habitats (A, C, E, arrowed) of Japanese Eudigraphis (B, D, F). A, B: E. takakuwai: A, Toyama Park, Shinjuku Ward, trunk of Zelkova serrata (17 October 2017); B, various stages were found under bark of trunks of Z. serrata at the same site. C, D: E. nigricans; C, Mizushiri Beach, Tottori City (18 October 2017); D, an adult found in the cavity under a rock. E, F: E. kinutensis; E, campus of Tottori University, Tottori City, Z. serrata (13 November 2017); F, E. kinutensis under the bark of trunks of Z. serrata (Ochidani Park, Tottori City, 10 November 2017).

Fig. 5. Dorsal (A, C, E) and ventral (B, D, F) views of Eudigraphis. A, B: E. takakuwai, female (Waita, Toyoura-cho, Shimonoseki City, 31 August 2017). C, D: E. nigricans, male (Uka, Toyoura-cho, Shimonoseki City, 1 September 2017). E, F: E. kinutensis (campus of Tottori University, Tottori City, 5 January 2018). All the scales = 1mm.

Fig. 6. Scanning electron microscope images of Eugdigraphis spp. A–C: E. takakuwai, male (Suzaki, Seiyo City); A, labrum and left antenna; B, ventral view of distal segments of left antenna; C, dorsal view of right part of head with 3 trichobothria a, b, c. D–F: E. nigricans, male (Mizushiri Beach, Tottori City); D, head; E, ventral view of labrum with lateral palps (LP) of gnathochilaria; F, Distal segments of left antenna (ventral view). G, H: E. kinutensis, male (Tottori University Campus); G, labrum; H, dorsal view of right antenna and trichomes on head.