Alienostreptus bicoloripes, Pimvichai & Akkari & Semenyuk & Constant & Enghoff, 2020

Pimvichai, Piyatida, Akkari, Nesrine, Semenyuk, Irina, Constant, Jerôme & Enghoff, Henrik, 2020, A strikingly coloured new giant millipede from Vietnam has copycat in Borneo (Diplopoda, Spirostreptida, Harpagophoridae), European Journal of Taxonomy 722, pp. 1-15 : 5-11

Alienostreptus bicoloripes sp. nov.

urn:lsid:zoobank.org:act:2142CC0F-B6FD-40C6-8A7C-B3F291D5882E

Figs. 2–6 , 8

Diagnosis

Differs frOm the Only Other species in the genUs, A. alienus , by:

- larger size

- straight preanal process (epiproct)

- tip of anterior coxal fold (ac) fOrming a flattened, sickle-shaped lamella with serrate margins

- canopy of anterior coxal fold (ca) with a broad, rounded lobe (in A. alienus with serrate margins)

- apical part of telopodite forming a single broadly expanded sheet, in A. alienus ending in two branches

- tibial spine much shorter than in A. alienus

Etymology

The species epithet refers to the strikingly bi-coloured legs.

Type material

Holotype

VIETNAM • ♂, Gia Lai PrOv., KOn ChU Rang NatUre Reserve ; 14°28′28″ N, 108°32′27″ E; 500– 1200 m a.s.l.; 13–20 Jul. 2018; J. Constant, J. Bresseel and X. Vermeersch leg.; GTI project; RBINS I.G.33.769/001.

Paratypes

VIETNAM • 1 ♂, 2 ♀♀; same cOllectiOn data as fOr hOlOtype; RBINS I.G.33.769/002 , I.G.33.769/003 , I.G.33.769/004 • 3 ♂♂, 1 ♀, 1 jUvenile; Gia Lai PrOv., KOn ChU Rang NatUre Reserve ; 14°27–31′ N, 108°32–36′ E.; 950–1050 m a.s.l.; 23 May–2 JUn. 2016 and 26 Mar.–6 Apr. 2018; I. SemenyUk leg.; ZMUM .

Description

Males

Adult males (the holotype and paratypes) with 58–60 podous rings, no apodous rings. Length 16–17 cm, width 10.3–10.5 mm. Overall colour of living specimen ( Fig. 2 A–C) including antennae, prozona, metazona, epiproct, paraprocts and hypoproct dark brown (almost black). Legs and antennae bi-coloured, antennomeres 1–4, legs from coxae to postfemora brownish orange; antennomeres 5–7, tibiae and tarsi of legs yellow.

HEAD. Head capsule smooth, no supralabral setae; eyes moderate in size, ommatidia in 7 horizontal rows, eye of one male with 9 + 10 + 9 + 8 + 6 + 5 + 3 = 50 ommatidia.

ANTENNAE. Almost reaching back to body ring 3, length of antennomeres: 2>3>4>5> 1>6> 7.

MANDIBLE. Stipes with disto-posterior lobe, ventral side of lobe thickened, with pale, soft area. GNATHOCHILARIUM. Stipites distally with ovoid, poorly sclerotized, hairless area in middle of which small sclerOtized ‘island’ carries One single spine-like seta.

COLLUM ( Fig. 3A ). Lateral lobe anteriorly with large, smooth, rounded, protruding extension; posteriorly with rectangular corner and several wrinkles.

BODY RINGS. With slightly vaulted metazona and with distinct longitudinal striation on metazona, more distinct on ventral parts but extending to dorsal parts as well; ozopores small, situated up to 2 × their diameter behind suture. No sigilla.

EPIPROCT ( Fig. 3B ). With long, straight process protruding beyond paraprocts. Paraprocts smooth, with rOUnded margins (ʻlipsʼ).

STERNA. Smooth, stigmatal grooves short and shallow, reaching to tip of coxae.

LEGS. Relatively long; tarsi, tibiae and part of postfemora visible from above when legs are extended laterad. Length Of pOdOmeres: femUr = tarsUs>tibia>prefemUr>pOstfemUr>cOxa> claw. Claw slender, length almost 4× proximal height, no accessory claw. Prefemora dorsally with blunt longitudinal ridge. COxae Of seventh pair Of legs nOt mOdified. SetatiOn Of pOsteriOr leg frOm a midbOdy ring: cOxa: 5 ventral setae; prefemUr: 3 dOrsal spinelike setae, One lOng and several shOrt, ventral fine setae; femUr: 4 ventral fine setae; pOstfemUr: 3 ventral fine setae; tibia: nO setae; tarsUs: 1 apicOdOrsal and 4 ventral spinelike setae. Ventral pads ( Fig. 3 C–D) Only On tibiae, On all legs except first twO pairs, pad relatively lOng, distal ends Overlapping ca ¼ Of tarsi, terminating in triangUlar prOjectiOn.

GONOPODS ( Figs 4–5 ). Sternum absent. Paracoxites (px) forming small triangular lobe laterally at base of coxae. Coxae oval, apically rounded. Anterior coxal folds (ac) ( Figs 4A , 5A ) oval (narrower than in A. alienus ), forming V-shaped longitudinal trough in anterior view, each ac concave in posterior view; mesally with one mesad lobe (fl), blUntly triangUlar in OUtline; distally with flattened, sickle-shaped lObe having mesal broad, rounded expansion forming canopy ( Fig. 4 C ). Posterior coxal fold (pc) ( Figs 4B , 5B ) very low, less than half as high as ac, consisting of two low, parallel ridges separated by smooth trough; lateralmost ridge (lr) with small, pointed triangular process (tp) laterally; mesal ridge (mr) cOntinUing as sagittal ridge ending in small flap-like lObe (fl). Telopodite ( Figs 4 D–E, 5C–D) leaving coxite over posterior coxal fold; femoral spine duplicated (fe1, fe2), fe1 very long, broader than fe2, straight, cOncave at ¼ Of mesal margin, terminally slightly cUrved, ending in sharp pOint; fe2 slender, very long, as long as fe1; tibial spine (ti) short, slender. Apical part of telopodite a broadly expanded sheet, with additional spine (as) at base, with row of setalike spines (sp) laterally, with several transverse ridges (tr) across along outer rim surface.

Females

Adult females (paratypes) with 59–60 podous rings, no apodous rings. Length 16–18 cm, width 13.4– 13.9 mm.

Other non-gonopodal characters as in male, except:

- antennae not reaching past collum

- mandible without stipital lobe

- gnathochilarium without poorly sclerotized area on stipes

- collum with more rounded corners

LEGS. Shorter, tarsi and part of tibiae visible from above when legs extended laterad. Length of pOdOmeres: femUr>tarsUs>tibia>prefemUr =pOstfemUr>cOxa>claw. SetatiOn Of a pOsteriOr leg frOm midbody ring: coxa with 7 ventral setae; prefemur with 7 dorsal spinelike setae, 1 apocidorsal and several ventral fine setae; femUr with 5 ventral fine setae; pOstfemUr with 1 apicOdOrsal and 4 ventral fine setae; tibia with 1 apicOdOrsal and 5 ventral fine setae; tarsUs with 1 dOrsal and 4 ventral spinelike setae.

Distribution

Gia Lai and Kon Tum provinces, Vietnam ( Fig. 8 ).

Ecology

Alienostreptus bicoloripes sp. nov. is found in a mixed tropical forest, formed mainly by broadleaf trees with tree ferns ( Cyathea Sm. sp. and others) ( Fig. 6 A–D). At Kon Chu Rang Nature Reserve, adults were active in the daytime as well as at night. Juveniles were hiding all the time. Adults were distributed over a wide range of habitats, from the very bottom of valleys to the dry ridges with coniferous forest, which is not very typical of millipedes. The second visit to the Kon Chu Rang Nature Reserve was almOst One and a half mOnths earlier than the first One (26 March–6 April 2018), in early spring, and it was ObviOUsly the peak Of this species’ abUndance. NUmerOUs jUveniles were Observed alOng the streams in valleys ( Fig. 2D ). They mainly OccUpy a very specific habitat avOided by all Other millipedes, viz, soaking wet clumps of leaf litter at the edge of streams and rivers, and also a surrounding area with a gradually decreasing water content. Leaf litter clumps caught by stones in streams also appeared as a habitat for juveniles. Sometimes they occupy troughs formed by rotten fallen trees next to the stream, which also contain a thick layer of wet leaf litter. Juveniles form loose aggregations in certain patches. They spend a few days in One spOt, eating leaf litter and accUmUlating excrement in a ʻchamberʼ, then leave the ʻchamberʼ and mOve tO anOther spOt. JUveniles may be resistant tO acUte flOOding as the leaves they inhabit are already soaking wet, and after frequent rains, the water level rises and covers most of the habitat. Three juveniles of later stages were found roaming around on leaf litter near the stream.

At KOn PlOng prOtected fOrest, KOn TUm PrOvince, Vietnam, (14°43′ N, 108°18′ E, 1050 m a.s.l.), we have not collected specimens due to technical issues. Adult specimens of A. bicoloripes sp. nov. were found exclusively on the surface of leaf litter on hill slopes above streams. Some were eating mushrooms, others roaming.

A ʻ copycat ʼ specimen from Borneo?

Clement Sim, Peter Petersen and Nicky Bay have taken photographs of a giant millipede from Kuching ( Fig. 7A ), Matang (1°36′46.4″ N, 110°12′10.5″ E) ( Fig. 7B ), and KUbah NatiOnal Park near KUching ( Fig. 7 C–D), Borneo ( Malaysia: Sarawak) which has a very similar colour to that of A. bicoloripes sp. nOv. AccOrding tO the phOtOs, there are, hOwever, differences ( Table 1 ).

Specimens from Borneo are not available. However, despite the unusual colour pattern shared with A. bicoloripes sp. nOv., it is clear that it belOngs tO a different genUs, based On the presence Of ventral soft pads on the postfemora of the male legs.

Figures

Fig. 2. Alienostreptus bicoloripes sp. nov. A–C. Living females (from Kon Chu Rang Nature Reserve, Gia Lai Province), paratypes (RBINS, ZMUM). D. Living juveniles from Kon Plong protected forest, Kon Tum Province.

Fig. 3. Alienostreptus bicoloripes sp. nov., holotype (RBINS I.G.33.769/001). A. Head and anterior body rings, lateral view. B. Ultimate body rings, lateral view. C. Head and anterior body rings including seventh pair of legs, ventral view. D. Legs showing soft ventral pads, lateral view.

Fig. 4. Alienostreptus bicoloripes sp. nov., holotype (RBINS I.G.33.769/001). A. Anterior gonopod, anterior view. B. Anterior gonopod, posterior view. C. Left gonopod coxa, apical view. D. Left telopodite, posterior–mesal view. E. Left telopodite, anterior–lateral view.

Fig. 5. Alienostreptus bicoloripes sp. nov., paratype (ZMUM). A. Right anterior gonopod, anterior view drawing. B. Right anterior gonopod, posterior view drawing. C. Left telopodite, posterior–mesal view drawing. D. Left telopodite, anterior–lateral view drawing.

Fig. 6. Habitats of Alienostreptus bicoloripes sp. nov. in Vietnam. A–C. Kon Chu Rang Nature Reserve, Gia Lai Province. D. Kon Plong protected forest, Kon Tum Province.

Fig. 8. Known distribution of Alienostreptus Pimvichai et al. 2010 spp. and sUperficially similar specimens from Borneo. Droplets vary in size only to improve readability.

Fig. 7. Specimens from Borneo (Malaysia: Sarawak). A. Living female from Kuching (Photo by Clement Sim). B. Living male from Matang (Photo by Peter Petersen). C–D. Living male from Kubah National Park (Photos by Nicky Bay).