Circulocryptus kompantsevi, Golovatch, 2018

Golovatch, Sergei I., 2018, Further notes on the millipede family Cryptodesmidae in Southeast Asia, with descriptions of a new genus and two new species from Indochina (Diplopoda: Polydesmida), Raffles Bulletin of Zoology 66, pp. 361-370 : 361-364

Circulocryptus kompantsevi , new species

( Figs. 1 , 2 )

Material examined. Holotype male ( ZMUM), Cambodia, Kampot Prov., Elephant Mountains, Phnom Pokor National Park, inside a rotten fruit body of Gonoderma fungus,

10°37′08.89″N, 104°04′40.87″E, 8.XII.2017, leg. A. Kompantsev.

Diagnosis. Differs from both known congeners, C. fallei Golovatch, 2016 , the type-species from southern and central-southern Vietnam ( Golovatch, 2016; Golovatch & VandenSpiegel, 2017), and C. javanicus Golovatch, 2018 , from western Java, Indonesia ( Golovatch, 2018), by the conspicuously swollen anterior half of the collum and certain minor details of the gonopodal structure, i.e., the shapes of the prefemoral process and basal branch. In showing 25 radii at the anterior margin of the collum, only four transverse rows of tubercles and four lateral lobulations on each of postcollum metaterga, C. kompantsevi , new species, seems to be more similar to the geographically closer C. fallei , but differs clearly in the light body (vs. sometimes dark), the presence of a fimbriate prefemoral process p (vs. a finger-shaped trichostele) on the gonopodal telopodite, the latter’s branch b being somewhat longer than branch sph ( Fig. 2B, C ).

Name. Honours Dr. Aleksandr Kompantsev, the collector.

Description. Length ca 16 mm, width of midbody pro- and metazonae 1.6 and 3.8 mm, respectively. General colouration in alcohol rather uniformly light pinkish ( Fig. 1 ), only antennae brown to dark purplish brown, increasingly infuscate distad; head, anterior half of collum, distal halves of postcollum paraterga, mid-dorsal parts of prozonae, sterna and legs light yellowish to creamy.

Body with 20 segments. In width, head << collum <segment 2 <3 <4 = 15; thereafter body gradually tapering towards telson. Head densely setose, between and behind antennae densely and clearly microgranulate; epicranial suture superficial, more distinct in vertigial region. Antennae very short and densely setose, clearly clavate, C-shaped ( Fig. 1A–C ); in length, antennomere 1 = 2 = 4 = 7 <3 <6 <5; antennomeres 5 and 6 subequally high, each with a small, compact, apicodorsal group of minute bacilliform sensilla. Interantennal isthmus ca 1.3 times as broad as diameter of antennal socket.

Tegument mostly dull and clearly microgranulate almost throughout, only prozonae and strictures between pro- and metazonae shining, very finely shagreened (prozonae) or micro-alveolate (strictures). Dorsum strongly and regularly convex; paraterga mostly set at about upper 1/3 of body, very strongly developed, beginning with collum, regularly declined ventrad much like dorsum ( Fig. 1 ). Collum flabellate, completely covering the head from above, tauriform, anterior half distinctly swollen, posterior half clearly impressed and with 5–6 transverse, irregular rows of small, round, setigerous tuberculations; anterior margin regularly rounded, with 25 indistinct radii, central setigerous lobulations especially inconspicuous compared to more lateral ones; paraterga narrowly rounded caudally, indistinctly lobulate laterally and caudally as well. Postcollum paraterga very broad, each much broader than prozona; anterior margin/shoulder always entire, mostly nearly straight and narrowly bordered, increasingly, but faintly curved caudad towards telson, with neither radii nor crenulations, only anterolateral corner slightly rounded and bearing a particularly small lobulation, followed by three radii and larger lobulations along a subquadrate lateral edge, caudal corner drawn increasingly behind rear tergal margin only in segments 16–19; paraterga 19 produced nearly as far behind as tip of epiproct. Caudal margins of paraterga both radiate and increasingly strongly lobulate laterad, typically with 12+12 setigerous lobulations on each side, regardless of caudolateral ones ( Fig. 1 ). Mid-dorsal parts of metaterga with four transverse, rather regular rows of small, setigerous, round tubercles/knobs, caudal row being especially regular; 1–3 irregular rows of dorsal knobs increasingly obliterated when extended onto distal parts of paraterga. Tergal setae short, light, pointed, usually well visible, 1/4–1/5 as long as metatergite. Neither an axial line nor pleurosternal carinae. Ozopores present anteriorly at least at the very base of paraterga 7 (in a broken body), invisible, pore formula untraceable. Stricture dividing pro- and metazonae broad, shallow and more shining than adjacent metazonae. Limbus brush-like, very densely microspiculate ( Fig. 1C, D ). Epiproct ( Fig. 1A, B, D ) conical, slightly emarginate at apex, dorsal and lateral tubercles evident. Hypoproct semi-circular, 1+1 caudal setae clearly separated, borne on evident tubercles ( Fig. 1D ).

Sternites narrow ( Fig. 1C, D ), densely setose, clearly impressed along main axis, distinctly broadened only between coxae 7 and 9 (male). Legs long and slender, without modifications ( Figs. 1A, C, D , 2A ), almost as long as paratergal width; in length, tarsi = femora >> coxae = prefemora = postfemora = tibiae; gonapophyses on coxae 2 small cones (male); neither adenostyles nor tarsal brushes. Claws simple, slightly curved ventrad. Gonopod aperture transversely ovoid, caudal and lateral margins thin and slightly elevated ( Fig. 1C ).

Gonopods ( Figs. 1C , 2B, C ) in situ held parallel to each other. Telopodite typically subcircular, very strongly curved caudad, bipartite, with a short, “prefemoral”, fimbriate, basal process (p) on lateral face. Main, basal part (b) of telopodite ribbonshaped, slightly curved anteriad and subtruncate apically, extended in distal third into a long, solid, subunciform, bare, lateral solenomere (sl), the latter at its base bearing a fringed, membranous, hyaline lobe (l). A distinct accessory seminal chamber (a) and a short duct devoid of a hairy pulvillus lying in distal part of solenophore (sph) just opposite sl, branch b being somewhat longer than branch sph.

Remarks. As noted above, the genus Circulocryptus Golovatch, 2016 has hitherto been known to contain only two species: C. fallei from Vietnam ( Golovatch, 2016; Golovatch & VandenSpiegel, 2017), and C. javanicus from Java, Indonesia ( Golovatch, 2018). The third, new species fails to alter the generic diagnosis as reformulated by Golovatch (2018). This primarily concerns an obviously subcircular, biramous, highly complex gonopodal telopodite that shows an accessory seminal chamber and its duct on a separate solenophorous branch (sph) which lies opposite the basal branch (b) with a spiniform solenomere (sl). The presence in C. kompantsevi , new species, of a small, but evident gonoprefemoral process (p) which is absent from C. javanicus and often absent from C. fallei also seems characteristic of the genus. Whereas the latter trait is shared with a few other genera of Cryptodesmidae in Southeast Asia ( Golovatch, 2016), the former feature is unique not only within the family, but also amongst all known genera of the order Polydesmida ( Golovatch, 2018) . This alone warrants the promotion of Circulocryptus to a cryptodesmid tribe of its own, Circulocryptini , tribus nova, which also includes the new genus described below.

The following key can be proposed to separate all three species of Circulocryptus known to date:

1. General colouration light, mostly light brown to yellow ( Fig. 1 ). Collum conspicuously swollen in anterior half and impressed in posterior one ( Fig. 1A, B ), anterior margin with 25 radii. Postcollum paraterga each with four lateral lobulations, anteriormost of which especially small ( Fig. 1 ). Gonopod with a fimbriate, basal, prefemoral process (p) on lateral face, telopodite with branch b being somewhat shorter than branch sph ( Fig. 2 ). Cambodia.............. C. kompantsevi , new species

– General colouration sometimes dark, red-brown to blackish. Collum not swollen in anterior half. Gonopodal telopodite with branch b being somewhat longer than branch sph ................2

2. Collum with 29 radii at anterior margin, postcollum metaterga each with 5–6 transverse rows of setigerous tubercles and five lateral lobulations. Tip of branch b of gonopodal telopodite retrorse. Java, Indonesia....................................... C. javanicus

– Collum with 25 radii at anterior margin, postcollum metaterga each with four transverse rows of setigerous tubercles and four lateral lobulations. Tip of branch b of gonopodal telopodite curved forward. Vietnam. ............................................ C. fallei

Figures

Fig. 1. Circulocryptus kompantsevi, new species, holotype. Habitus, A, lateral view; B, dorsal view; C, anteroventral view; D, posteroventral view. Pictures taken not to scale.

Fig. 2. Circulocryptus kompantsevi, new species, holotype. A, Leg 9, lateral view; B, right gonopod, lateral view; C, right gonopod, mesal view. Scale bar = 0.1 mm (A) and 0.2 mm (B, C). Designations: a = accessory seminal chamber; b = basal branch; l = hyaline fringed lobe at base of solenomere; p = prefemoral process; sl = solenomere; sph = solenophorous branch.