Desmoxytes planata (Pocock, 1895)

Srisonchai, Ruttapon, Enghoff, Henrik, Likhitrakarn, Natdanai & Panha, Somsak, 2018, A revision of dragon millipedes I: genus Desmoxytes Chamberlin, 1923, with the description of eight new species (Diplopoda, Polydesmida, Paradoxosomatidae), ZooKeys 761, pp. 1-177 : 1

Desmoxytes planata (Pocock, 1895) Figs 5, 6, 7, 8, 67, 68, 69, 70, 71, 72, 73, 74

Prionopeltis planatus Pocock, 1895: 829. Attems 1914: 204; 1936: 215; 1937: 114.

Pratinus planatus - Jeekel 1964: 63 (in key); 1968: 61. Mauriès 1980: 161.

Desmoxytes planata - Jeekel 1980a: 652; 1980b: 124. Golovatch and Korsós 1992: 25. Golovatch and Enghoff 1994: 60. Shelley and Lehtinen 1998: 88. Enghoff 2005: 96. Decker 2010: 29. Nguyen and Sierwald 2013: 1240. Zoysa et al. 2016: 474. Golovatch and Wesener 2016: 45. Likhitrakarn et al. 2017: 20.

Desmoxytes coniger Chamberlin, 1923: 165. Jeekel 1980a: 652 (synonymised).

Euphyodesmus greeni (Silv.) Attems, 1936: 213. Jeekel 1980a: 652 (synonymised).

Euphyodesmus greeni - Attems 1937: 128.

Pratinus greeni - Jeekel 1964: 63 (in key).

Euphyodesmus (Ceylonesmus) vector Chamberlin, 1941: 33. Jeekel 1980a: 652 (synonymised).

Pratinus vector - Jeekel 1964: 63 (in key).

Pratinus rastrituberus Zhang, 1986: 255. Golovatch and Enghoff 1994: 60 (synonymised).

Material examined.

Lectotype. Male (NHMUK, 1892.5.4.64-74), MYANMAR, Andaman Sea, Great Cocos Island, leg. E. W. Oates; designated by Mauriès (1980).

Paralectotypes. 1 male, 2 females pinned through body (>10 males and>15 females broken and mixed) (NHMUK), MYANMAR, Andaman Sea, Great Cocos Island, leg. E. W. Oates.

Other material examined.

CHINA: 8 males, 2 females (CUMZ), Yunnan, Xishuangbanna, Mengla, 213 national road near Menglunzhen, Munlun Village, 21°56'40"N, 101°13'45"E, ca. 576 m a.s.l., 26 November 2016, leg. S. Panha, C. Sutcharit and E. Jeratthitikul.

FIJI: 1 female, 1 juvenile (ZMUC), Viti Levu Suva, in garden, 2-3 September 1995, leg. A. Van Harten. 1 male (ZMUC), Upper Sigataka Valley, 6 March 1995, leg. A. Van Harten. 1 female (ZMUC), Colo-i-Suva Forest Park, 10 January 1995, leg. A. Van Harten. 3 females (ZMUC), Viti Levu, Colo-i-Suva Forest Park, 23-27 August 1995, leg. A. Van Harten. 1 male (ZMUC), Viti Levu, Colo-i-Suva Forest Park, 3 March 1995, leg. A. Van Harten. 4 males (ZMUC), Viti Levu, Colo-i-Suva Forest Park, 22 October 1995, leg. A. Van Harten. 1 male (ZMUC), Viti Levu, Colo-i-Suva Forest Park, 1995, leg. A. Van Harten. 1 male (ZMUC), Colo-i-Suva Forest Park, 29 March– 6 April 1995, leg. A. Van Harten.

MYANMAR: 4 males (CUMZ), Tanintharyi Region, Myeik, 20 km northeast of Monoron, near Lenya National Park, Lampane Village, Ngawun Chaung River, 11°40'18"N, 99°13'29"E, ca. 44 m a.s.l., 9 June 2015, leg. ASRU members and FFI staff.

SEYCHELLES: 2 females (ZMUC), Mahé, ca. 50 m above Hotel Reef (near airport), under dead banana leaves, 8 October 1997, leg. H. Sturm.

THAILAND:

Chiang Mai Province: 1 female (ZMUC), Mae Rim District, Queen Sirikit Botanical Garden, June 1998. leg. R. Meier. 2 males, 6 females (ZMUC), Chiang Mai Province, Chiang Mai, in garden, ca. 300 m a.s.l., 26 September 1981, leg. ZMUC staff. 1 male, 1 female (ZMUC), Chiang Mai, in garden, ca. 300 m a.s.l., 2 October 1981, leg. ZMUC staff. 1 female (ZMUC), Doi Inthanon National Park, Siripum Waterfall, ca. 1200-1300 m a.s.l., 2 October 1981, leg. ZMUC staff. 1 female (ZMUC), Fang Horticultural Station, ca. 1200-1300 m a.s.l., 21 October 1981, leg. ZMUC staff. 2 females, 2 juveniles (CUMZ), Chiang Dao District, Wat Tham Chiang Dao, 19°23'46"N, 98°55'45"E, ca. 442 m a.s.l., 20 July 2008, leg. ASRU members. 1 female (CUMZ), Mueang Chiang Mai District, 700 years house of Chiang Mai, 2 October 2009, leg. S. Panha and ASRU members. 1 female (CUMZ), Mueang Chiang Mai District, 700 years house of Chiang Mai, 2 October 2009, leg. S. Panha and ASRU members. 1 female (CUMZ), Mae On District, Mae Kampong Waterfall, 18°51'56"N, 99°21'18"E, ca. 1069 m a.s.l., 27 September 2009, leg. S. Panha and ASRU members.

Chiang Rai Province: 7 males, 4 females (CUMZ), Mae Lao District, Dong Mada Subdistrict, Huai Kon Kom, beside road no.118, 19°44'55"N, 99°39'33"E, ca. 472 m a.s.l., 27 November 2009, leg. ASRU members.

Chumphon Province: 1 male, 1 female (CUMZ), Pathio District, Phitsadarn Cave (Tham Phitsadarn), 10°45'36"N, 99°13'46"E, ca. 106 m a.s.l., 29 August 2015, leg. ASRU members. 2 females (CUMZ), Pathio District, Phitsadarn Cave (Tham Phitsadarn), 10°45'36"N, 99°13'46"E, ca. 106 m a.s.l., 5 January 2017, leg. ASRU members.

Kanchanaburi Province: 14 males, 11 females, 2 juveniles (CUMZ), Thong Pha Phum District, Thong Pha Phum Forest Garden, 14°40'06"N, 98°35'42"E, ca. 171 m a.s.l., 8 May 2014, leg. ASRU members. 1 male, 5 females (CUMZ), Thong Pha Phum District, Thong Pha Phum Forest Garden, 14°40'06"N, 98°35'42"E, ca. 171 m a.s.l., 24 July 2016, leg. P. Pimvichai, T. Backeljau, P. Prasankok and N. Nantarat. 2 males, 2 females, (CUMZ), Thong Pha Phum District, Huai Ka Yeng Hot Spring, 14°38'57"N, 98°31'28"E, ca. 202 m a.s.l., 9 May 2014, leg. ASRU members. 1 male (CUMZ), Thong Pha Phum District, Wat Huay Charoen Srattha Tham, 14°39'27"N, 98°31'38"E, ca. 202 m a.s.l., 9 May 2014, leg. ASRU members. 2 males, 2 females (CUMZ), Sangkhla Buri District, Kroeng Krawia Waterfall, 14°58'55"N, 98°37'54"E, ca. 258 m a.s.l., 10 July 2009, leg. ASRU members. 2 females, 1 juvenile (CUMZ), Sri Sawat District, Erawan Waterfall National Park, 14°22'09"N, 99°08'41"E, ca. 102 m a.s.l., 28 August 2011, leg. ASRU members. 1 male, 1 broken fragment (CUMZ), Thong Pha Phum District, Tham Khao Noi Bureau of Monks, 14°41'55"N, 98°31'34"E, ca. 233 m a.s.l., 21 August 2015, leg. R. Srisonchai and C. Sutcharit. 3 females, 6 juvenile (CUMZ), Thong Pha Phum District, Kroeng Krawia Check Point, 14°56'32"N, 98°40'10"E, ca. 343 m a.s.l., 12 October 2015, leg. C. Sutcharit and ASRU members. 8 males, 9 females (CUMZ), Sangkhla Buri District, Wat Tham Su Kho, 15°02'14"N, 98°34'58"E, ca. 194 m a.s.l., 16 August 2016, leg. C. Sutcharit and ASRU members. 1 female (CUMZ), Sangkhla Buri District, Kra Teng Jeng Waterfall, 15°01'30"N, 98°36'03"E, ca. 202 m a.s.l., 16 August 2016, leg. C. Sutcharit and ASRU members. 7 males, 1 female (CUMZ), Sangkhla Buri District, Ban Song Karia, beside road no. 323, 15°13'01"N, 98°27'06"E, ca. 204 m a.s.l., 16 August 2016, leg. C. Sutcharit and ASRU members. 19 males, 26 females (CUMZ), Sangkhla Buri District, Tham Thep Prachao Praya Nak Kharach, 16 August 2016, leg. C. Sutcharit and ASRU members. 1 female (CUMZ), Sangkhla Buri District, Tham Kaeo Sawan Bandhan, 15°18'18"N, 98°24'57"E, ca. 339 m a.s.l., 16 August 2016, leg. C. Sutcharit and ASRU members. 2 females (CUMZ), Thong Pha Phum District, Wat Tha Kha-nun, 14°44'36"N, 98°38'19"E, ca. 113 m a.s.l., 16 August 2016, leg. C. Sutcharit and ASRU members. 4 males, 9 females (CUMZ), Thong Pha Phum District, Phuphrai Thannam Resort, 14°44'07"N, 98°38'39"E, ca. 110 m a.s.l., 16 August 2016, leg. C. Sutcharit and ASRU members. 3 males (CUMZ), Mueang Kanchanaburi District, Lat Ya Subdistrict, Klong Ta Ploen, 19 December 2016, leg. E. Jeratthitikul.

Lampang Province: 1 male, 5 male fragments, 5 females (CUMZ), Mae Mo District, Chao Por Pra Thu Pha Shrine, 18°30'48"N, 99°49'13"E, ca. 587 m a.s.l., 23 October 2008, leg. ASRU members. 1 female (CUMZ), Mae Mo District, Chao Por Pra Thu Pha Shrine, 18°30'48"N, 99°49'13"E, ca. 587 m a.s.l., 22 October 2015, leg. ASRU members.

Mae Hong Son Province: 12 males, 12 females (CUMZ), Mueang Mae Hong Son District, Tham Pla-Namtok Pha Suea National Park, 19°30'07"N, 98°00'23"E, ca. 398 m a.s.l., 19 July 2008, leg. ASRU members. 1 male, 5 females, 6 juveniles (CUMZ), Mae Sariang District, Mae Sariang Highway Division, 18°12'37"N, 97°56'15"E, ca. 296 m a.s.l., 16 January 2015, leg. ASRU members. 9 males, 14 females (CUMZ), Mueang Mae Hong Son District, Tham Phadaeng, 19°25'23"N, 97°59'04"E, ca. 288 m a.s.l., 19 September 2008, leg. ASRU members.

Phayao Province: 5 males, 6 females (CUMZ), Phusang District, Phu Sang Waterfall, 19°39'49"N, 100°22'36"E, ca. 472 m a.s.l., 24 October 2008, leg. ASRU members. 1 male (CUMZ), Phusang District, Phu Sang Waterfall, 19°39'49"N, 100°22'36"E, ca. 472 m a.s.l., 11 October 2014, leg. ASRU members. 1 broken male, 3 females (CUMZ), Phusang District, Phu Sang Waterfall, 19°39'49"N, 100°22'36"E, ca. 472 m a.s.l., 19 November 2012, leg. ASRU members. 1 male, 3 females (CUMZ), Chiang Kham District, Tham Phadaeng, 19°30'00"N, 100°27'10"E, ca. 495 m a.s.l., 24 October 2008, leg. ASRU members.

Phetchaburi Province: Mixed rings - probably 2 males (CUMZ), Kaeng Krachan District, Huai Mae Priang Subdistrict, Ban Dan Ngo, 12°48'41"N, 99°33'46"E, ca. 252 m a.s.l., 1 September 2007, leg. ASRU members. 1 male, 4 females, 1 juvenile (CUMZ), Khao Yoi District, Wat Paung Malai (Wat Tham Khao Iko), 13°18'42"N, 99°47'03"E, ca. 42 m a.s.l., 24 August 2016, leg. ASRU members. 17 males, 16 females (CUMZ), Khao Yoi District, Wat Paung Malai (Wat Tham Khao Iko), 13°18'42"N, 99°47'03"E, ca. 42 m a.s.l., 24 October 2016, leg. ASRU members.

Phrae Province: 3 males, 3 females (CUMZ), Rong Kwang District, Huai Rong Waterfall, 18°26'28"N, 100°26'60"E, ca. 441 m a.s.l., 31 August 2014, leg. ASRU members. 2 females (CUMZ), Den Chai District, Suan Sai Thong Restaurant, 17°58'17"N, 100°04'22"E, ca. 170 m a.s.l., 9 October 2008, leg. ASRU members. 1 male, 2 females (CUMZ), Den Chai District, Suan Sai Thong Restaurant, 17°58'17"N, 100°04'22"E, ca. 170 m a.s.l., 24 August 2014, leg. ASRU members. 31 males, 30 females (CUMZ), Den Chai District, Suan Sai Thong Restaurant, 17°58'17"N, 100°04'22"E, ca. 170 m a.s.l., 31 August 2014, leg. ASRU members.

Prachuap Khiri Khan Province: 1 male, 1 female, broken and mixed rings (CUMZ), Bang Saphan District, Wat Khao Tham Ma Rong, 11°12'05"N, 99°29'52"E, ca. 22 m a.s.l., 12 October 2008, leg. ASRU members. 8 males, 4 females (CUMZ), Kui Buri District, Hat Kham Subdistrict, near Kui Buri National Park, 12°03'13"N, 99°37'53"E, ca. 141 m a.s.l., 7 August 2014, leg. ASRU members. 7 males, 4 females (CUMZ), Kui Buri District, Hat Kham Subdistrict, near Kui Buri National Park, 12°03'13"N, 99°37'53"E, ca. 141 m a.s.l., 9 August 2016, leg. ASRU members. 4 males, 1 female (CUMZ), Kui Buri District, Hat Kham Subdistrict, near Kui Buri National Park, 12°03'13"N, 99°37'53"E, ca. 141 m a.s.l., 11 October 2010, leg. ASRU members. 9 males, 12 females (CUMZ), Mueang Prachuap Khiri Khan District, Khao Ta Mong Lai Forest Park, 11°50'49"N, 99°49'35"E, ca. 14 m a.s.l., 24 October 2016, leg. ASRU members.

Ratchaburi Province: 1 female (CUMZ), Mueang District, Khao Bin Cave, 13°35'37"N, 99°40'00"E, ca. 73 m a.s.l., 8 September 1973, leg. CUMZ staff.

Sa Kaeo Province: 2 males, 2 females (CUMZ), Mueang Sa Kaeo District, Tayak Subdistrict, near Pang Sida National Park, 13°58'26"N, 102°12'15"E, ca. 68 m a.s.l., 17 July 2016, leg. A. Pholyotha.

Saraburi Province: 1 male (CUMZ), Muak Lek District, Chet Sao Noi Waterfall, 14°44'07"N, 101°11'30"E, ca. 158 m a.s.l., 11 October 2014, leg. S. Panha, P. Tongkerd and A. Pholyotha.

Tak Province: 2 males, 3 females, 1 fragment of male (CUMZ), Phop Phra District, Pha Charoen Waterfall, 16°30'04"N, 98°45'06"E, ca. 649 m a.s.l., 5 July 2009, leg. ASRU members. 3 males, 2 females, 1 juvenile, broken and mixed fragments (CUMZ), Umphang District, Khun Danai Restaurant, 16°02'32"N, 98°50'55"E, ca. 466 m a.s.l., 6 July 2009, leg. ASRU members. 1 broken male (CUMZ), Mae Sot District, PK House Hotel, 16°43'39"N, 98°34'13"E, ca. 217 m a.s.l., 5 July 2009, leg. ASRU members. 2 males, 4 females, 6 juveniles (CUMZ), Phop Phra District, Um Piam Village, 16°24'33"N, 99°00'22"E, ca. 1088 m a.s.l., 1 July 2015, leg. ASRU members. 7 males, 1 female, 1 juvenile (CUMZ), Umphang District, Thi Lo Su Riverside Resort, 16°02'47"N, 98°51'09"E, ca. 470 m a.s.l., 1 July 2015, leg. ASRU members. 20 specimens (CUMZ), Phop Phra District, Chao Por Phawo Phop Phra Shrine, near Ban Ja Dee Kho, 16°34'10"N, 98°40'03"E, ca. 554 m a.s.l., 2 July 2015, leg. ASRU members. 1 male (CUMZ), Umphang District, Mae Klong Kee Bureau of Monks, 16°13'46"N, 98°55'12"E, ca. 586 m a.s.l., 30 June 2015, leg. ASRU members.

Diagnosis.

Body black or brownish black; collum with three transverse rows of setae and setiferous tubercles (4+4 anterior setae, 1+1 intermediate and 2+2 posterior tubercles); metaterga 2-16 with two rows of 2+2 (anterior) setiferous cones and 2+2 (posterior) setiferous spines; ventral ridge (vrl) of lamina lateralis conspicuous; process (plm) of lamina medialis long, directed almost mesad; distal lobe (dlm) distally with two distinct lamellae. Similar in these respects to D. euros sp. n., but differs from that species by having paraterga vivid pink and hypoproct subtrapeziform with inconspicuous setiferous tubercles.

Type locality.

Great Cocos Island, Andaman Sea [Myanmar, Yangon Region].

Redescription.

SIZE: Length 16-26 mm (male), 20-28 mm (female); width of midbody metazona ca. 1.8 mm (male), 2.1 mm (female). Width of head ≤ collum ≥ body ring 2 ≥ 3 = 4 <5-16, thereafter body gradually tapering towards telson.

COLOUR (Figs 67, 68A, B): In life with body black or brownish black; head, antenna (except distal part of antennomere 7 and antennomere 8 whitish), metaterga, and surface below paraterga brownish black; paraterga vivid pink; sterna pinkish brown; epiproct brown; legs brownish pink; a few basal podomeres pinkish white. Colour in alcohol: after 120 years changed to pale brown, after 2-10 years changed to brown or pale brown.

ANTENNAE (Fig. 69D): Moderately long and slender, reaching to body ring 5 or 6 (male) and 4 or 5 (female) when stretched dorsally.

COLLUM (Fig. 69A): With 3 transverse rows of setae and setiferous tubercles, 4+4 anterior setae, 1+1 intermediate and 2+2 posterior tubercles (lateral seta in anterior row located almost at base of paraterga in some specimens, posterior tubercles in posterior row bigger than others); paraterga of collum low, elevated at ca. 10°-15°, directed caudolaterad, with one inconspicuous notch on lateral margin.

TEGUMENT: Slightly shining; prozona finely shagreened; metaterga and surface below paraterga finely microgranulate; collum, sterna and epiproct smooth.

METATERGA (Fig. 69 A–C): With 2 transverse rows of setiferous tubercles/cones/spines; metaterga 2-17 with 2+2 anterior tubercles/cones and 2+2 posterior cones/spines (lectotype and paralectotypes all with 2+2 anterior tubercles and 2+2 posterior tubercles/cones on metaterga 2-17); metaterga 18 and 19 with 2+2 anterior and 2+2 posterior tubercles.

PARATERGA (Fig. 69E, F): Directed caudolaterad on body rings 2-17, elevated at ca. 45° (male) 40° (female), in lectotype and paralectotypes less elevated than in others: at ca. 40° in male and 35° in female; directed increasingly caudad on body rings 18 and 19; anterior margin with 2 distinct notches, on lateral margin of body rings 9, 10, 12, 13, 15-18 with tiny denticle near the tip (tiny denticle of lectotype and paralectotypes poorly developed).

TELSON (Fig. 70 C–G): Epiproct: tip usually subtruncate (in some specimens slightly emarginate); lateral setiferous tubercles and apical tubercles usually conspicuous (in some specimens inconspicuous). Hypoproct subtrapeziform; caudal margin round, with inconspicuous setiferous tubercles.

STERNA (Fig. 71): Cross-impressions shallow. Sternal lobe between male coxae 4 swollen subtrapeziform/subsemicircular when seen in caudal view (round in lectotype and paralectotypes); base stout; slightly attenuated near tip; tip usually subtruncate (in some specimens round).

LEGS (Fig. 70 H–J): Long and slender. Male femora 5 and 6 slightly humped ventrally in middle portion.

GONOPODS (Figs 7, 8, 72, 73, 74): Coxa (cx) longer than prefemur. Cannula (ca) long and slender. Prefemur (pfe) ca. 2/3 as long as femur. Femur (fe) long and slender. Mesal sulcus (ms) and lateral sulcus (ls) conspicuous, very deep. Postfemur (pof) conspicuous, ventrally narrow, and short. Solenophore (sph) well-developed: lamina lateralis (ll) swollen, anterolaterally with an inconspicuous furrow; with conspicuous ventral ridge (vrl): lamina medialis (lm) well-developed; process (plm) long, spear-like, tip sharp (blunt in some specimens), directed mesad; distal lobe (dlm) distally with two distinct lamellae (mesal lamella smaller than second one); broad lobe (blm) dorsally thick at the edge, distinctly demarcated from distal lobe (dlm) by a conspicuous indentation. Solenomere (sl) very long.

Distribution and habitat.

This species was collected at several places together with D. octoconigera sp. n., D. golovatchi sp. n. and D. purpurosea , but these species apparently occupy different microhabitats. D. planata can be found all year round in humid places in environments strongly influenced by humans. It was very easy to find, mostly in plant farms or shaded gardens. Although D. planata was sometimes seen in areas close to another Desmoxytes species, the habitats where it was collected are clearly different: D. planata is often found in human-influenced habitats while the other ones live in natural habitats.

However, some specimens from Tham Khoa Ma Rong, Khoa Ta Mong Lai, Ban Yang Chum (all in Prachuap Khiri Khan Province) seem to be indigenous as they were found in limestone habitats, although not too far from human-influenced habitats. Certain introduced paradoxosomatid species seem to have penetrated natural habitats and have become more dominant and abundant than the native ones ( Jeekel 1980b), and D. planata at the above-mentioned locations may similarly have dispersed into the forest.

This species has been reported from Hawaii ( Chamberlin 1923, 1941). Because the only reliable records concern specimens taken from quarantine in Honolulu, it seems reasonable to delete D. planata from the Hawaii fauna. We believe that this species is transported easily by global commerce, most probably in soil-containing or plant-associated materials.

The origin of D. planata was assumed to be Burma or Malaya by Jeekel (1980a). Later, Shelley and Lehtinen (1998) regarded it more probable that this species occurs naturally in Thailand and China. Based on all recent data analysed by us, D. planata may originally be native to Thailand or Myanmar. Surprisingly, however, no specimen of D. planata has yet been found in Cambodia, Laos, or Malaysia, possibly owing to insufficient surveys in these areas.

Decker (2010) reported D. planata from eastern Thailand, viz., Namtok Phliu (Chantaburi Province), Khao Chamoa National Park (Rayong Province) and Ko Chang National Park (Trat Province). However, these localities all lie in the distribution range of the very similar D. euros sp. n., and Decker’s specimens may well belong to the latter species.

Note on type material.

The lectotype was designated by Mauriès (1980). In the jar which contains lectotype and paralectotypes in NHMUK, there are three small vials:

- one vial contains the male lectotype with a label " Pratinus planatus (Poc.) male lectotype vid. Mauriès (Paris)", pinned through the body; collum and telson were broken off.

- a second vial with one male and two female paralectotypes (one female with only rings 10-20), all specimens pinned through the body.

- a third vial with broken specimens (>5 specimens).

There is also one more vial containing many broken and mixed specimens (>15 specimens).

Remarks.

The vivid pink paraterga are obviously aposematic.

According to many previous works, as well as our own results, this species seems to be almost pantropical. In order to assess morphological variability, we compared the gonopods of several specimens (including illustrations) reported from different localities: D. planata from Myanmar (lectotype and paralectotypes); D. coniger - ( Jeekel 1980b) from Hawaii taken from Java (Bogor); D. planata - (Mauries 1980) from Seychelles; D. planata - ( Shelley and Lehtinen 1998) and ( Golovatch and Enghoff 1994) from Fiji; Pratinus rastrituberus - (Zhang, 1986) from China. Combining the examination of previous works and the newly collected specimens from China, Myanmar, and Thailand, variation in morphological characters was as follows.

I. Variation within populations (Fig. 71)

- anterior row of tubercles on collum (usually with 4+4 anterior setae): in some specimens lateral setae located in anterior margin (conspicuous tubercles), in others lateral setae located almost at base of paraterga (inconspicuous tubercles).

- type of metatergal projections (anterior row and posterior row) on body rings 2-17: anterior tubercles/cones in some specimens, posterior cones/spines in others.

- tip of sternal lobe between male coxae 4: truncate in some specimens, quite round in others.

- process (plm) of lamina medialis: short in some individuals, long in others.

- tip of process (plm) of lamina medialis of specimens from Great Cocos Island: slightly emarginate in some, sharp in others.

- epiproct tip: in some specimens subtruncate, in others slightly emarginate.

II. Variation between populations

- Fiji population: posterior tubercles on collum seem to be bigger than in other populations.

- Fiji population: sternal lobe between male coxae 4 more round than in others.

- Great Cocos Island population: size seems to be smaller than in others (16-20 mm in male, 20-23 mm in female).

- Great Cocos Island population: metatergal tubercles shorter than in others.

On this basis, we strongly agree with Jeekel (1980a) and Golovatch and Enghoff (1994) with the synonymy of D. coniger , E. greeni , E. vector and P. rastrituberus under Desmoxytes planata . Although the type material of D. coniger in MCZ has not been examined by us, its identity with D. planata is clear from the photo and remarks given by Jeekel (1980a). The morphological characters of this specimen match perfectly with the others.

Desmoxytes planata is morphologically similar to D. euros sp. n. with which it shares the metaterga with 2+2 anterior tubercles/cones and 2+2 posterior cones/spines. Moreover, gonopod characters of these species are very similar in shape and processes. Based on morphological characters only, they could be supposed to be the same species. However, the colour of living specimens (paraterga) and shape of hypoproct are totally different, as well as ongoing COI analysis supports to separate them as different species.

Coexisting species.

D. golovatchi sp. n. and D. octoconigera sp. n. (see details under these species).