Dysmicodesmus jeekeli Mesibov, 2010, n. sp.
Creators: name: Mesibov, Robert
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Diplopoda
Polydesmida
Dalodesmidae
Dysmicodesmus
Dysmicodesmus jeekeli

description: Dysmicodesmus jeekeli, n. sp.
Figs 1 B, 1C, 4A–D; map Fig. 5
Holotype. Male. Australia, Tasmania, Blackwater Road, 41°10'18"S 144°55'45"E ± 25 m, 170 m, 14 June 2010, R. Mesibov, QVM 23:51826.
Paratypes. 3 males, 1 female, same details as holotype, QVM 23:51843.
Other material examined. 4 males, Anthony Road, Tas, 41°49'48"S 145°37'17"E (CP854680) ± 100 m, 840 m, 18 April 1989, NRCP personnel, QVM 23:51855; 1 male, same details but 21 April 1989, QVM 23:51857; 2 males, Savage River Pipeline Road, Tas, 41°18'40"S 145°16'47"E ± 1 km (pooled specimens from CP558247 and CP560255, ca 800 m apart; latitude-longitude is midway between the two sites), 500 m, 20 April 1989, NRCP personnel, QVM 23:51856; 1 male, 1 female, Bond Tier, Tas, 40°57'41"S 144°51'16"E ± 50 m, 100 m, 20 May 2010, R. Mesibov, QVM 23:51824, found in copula; 2 males, same details but ± 100 m and 23 May 2010, QVM 23:51825.
Description. Male/female approximate measurements: length 9/ 8 mm, ring 12 prozonite width 0.9/0.9 mm, ring 12 maximum width across paranota 1.2/1.2 mm. Freshly preserved specimens (Fig. 1 B) reddishbrown, lighter dorsally and on paranota; head, antennae and pre-anal ring light brown, antennae darker distally; legs pale, light brown distally.
Male with head 1 1/ 3X as wide as collum; frons and ventral 2/3 of vertex moderately setose; vertigial sulcus very weakly impressed but clearly marked with dark pigment in freshly preserved specimens, extending ventrally ca 2/3 of the way to top of antennal sockets; antennal sockets separated by ca 2X a socket diameter, slightly impressed, bordered laterally with slight depression, ventral side of depression swollen. Antenna clavate, short, reaching ring 3 when manually extended; antennomere 6 widest; relative antennomere lengths (3,6)>2>(4,5). Collum reniform (convex anteriorly). Tergites 2–4 much shorter than metatergite 5; relative overall widths ring 6>5>head>4>(3,2)>collum; metatergite widths 6–13 about equal, gradually decreasing 14–18. Ring 2 tergal margin very slightly below collum and ring 3 margins; no ventral pit on ring 2. Diplosegments (Fig. 4 A) with waist shallow but well-defined behind suture, without longitudinal ridges; prozonites and metazonites smooth, with flat, polygonal texture; metatergites without evident transverse furrow, and with 3 transverse rows of 10–12 low tubercles, round or slightly oblong (long axis longitudinal), tubercles less obvious on paranota, each tubercle with short seta near posterior edge; posterior metatergite margin with a few short setae. Paranota a little swollen, lateral margin thin, nearly level, at about 3/4 ring height in lateral view; anterior margin smoothly convex, without anterolateral shoulder; lateral margin gently convex, not obviously notched, bearing 2–3 very short lateral setae; posterolateral corner not produced, gently rounded, in line with straight posterior margin of metatergite, on some rings with small, rounded, seta-bearing tooth just medial to posterolateral corner. Limbus composed of flat, irregularly shaped, apically toothed tabs. Spiracles small with circular, slightly raised rims; on diplosegments with anterior spiracle just above anterior leg, posterior spiracle just above and midway between anterior and posterior leg bases. Ozopore small, round, near posterolateral corner of metatergite, slightly recessed; pore formula 5, 7, 9, 10, 12, 13, 15–18. Sternites about as long as wide, lightly setose, with deep transverse and shallow longitudinal impressions. Legs with prefemur swollen dorsally, femur less so, swelling maximal on legpairs 4–7. Leg 6 with relative podomere lengths tarsus>(prefemur, femur)>(tibia, postfemur); tarsus 1.5X as long as femur, nearly straight; femur proportionally longer on posterior legs. Leg 6 with brush setae and sphaerotrichomes tapering, pointed; brush setae on femur, prefemur and distal half of coxa/trochanter; sphaerotrichomes on postfemur, tibia, tarsus; sphaerotrichome shafts longer distally. Gonopore on distomedial bulge of leg 2 coxa, protected distally by semi-cylindrical cowl. Bases of legpairs 5–7 separated to accommodate retracted gonopods, legpair 4 bases also separated but less so; sternite adjoining coxa of legs 4–7 produced as low knob bearing cluster of short setae medially. Pre-anal ring lightly setose, hypoproct subtrapezoidal, epiproct small, rounded, extending slightly past anal valves. Spinnerets in square array with ventral pair in shallow recess.
Gonopod aperture ovoid, ca 1/3 width of prozonite, posterolateral corners raised. Gonocoxae short (between 1/4 and 1/3 as long as telopodite), narrow, truncated conical, not medially joined. Cannula prominent, inserting posteromedially on telopodite base. Telopodites (Figs 1 C, 4B) straight, reaching between legpairs 3 and 4 when retracted, basally tightly fused along a suture (Fig. 4 C), lightly fused medially to ca 1/3 telopodite height at a series of small, discrete, cuticular joins. Telopodite swollen just above base, the swelling protruding slightly posterodistally; a lobe-like smaller swelling on anterior telopodite surface at ca 1/4 telopodite height, directed slightly basally (Fig. 1 C). Telopodite divided at ca 2/3 height into cluster of 4 processes: (1) a rod-like, tapering, bluntly pointed solenomere arising posteromedially, curving first laterally, then medially, then posteromedially, with minute, irregularly shaped, lumpy growths along prostatic groove (Fig. 4 D); (2) a slightly flattened, tapering and bluntly pointed process arising anteriorly, bending posteriorly near base and curving slightly medially near tip, almost meeting the corresponding contralateral process, longer than the solenomere; (3) a flattened process arising posterolaterally and curving distally, the tip expanded, truncate and with a shallow, rounded notch laterally, the process shorter than the solenomere; (4) a small, slightly flattened process arising posteriorly just basal to solenomere, directed posterodistally and tapering to a point at about 1/2 solenomere height. Prostatic groove running on medial surface of telopodite to base of solenomere, then winding helically around solenomere to tip. A few scattered setae posteriorly to ca 1/ 3 telopodite height; telopodite densely and finely setose around posteromedial depression into which cannula inserts.
Female slightly shorter than male but about the same diameter; legs smaller and not swollen; epigynum about 1/2 ring width, posterior margin with medial projection shaped like inverted U; cyphopods not examined.
Distribution. Known from wet eucalypt forest and cool temperate rainforest at four localities over a narrow range ca 120 km long in northwest Tasmania (Fig. 5).
Etymology. In honour of the myriapodologist C.A.W. Jeekel (1922–2010), for his many contributions to the systematics of Australian millipedes.
Remarks. I found the nine 2010 specimens in curls of recently fallen (i.e. not yet rotted) branch bark from mature Eucalyptus obliqua trees, suggesting that adults of this species are arboreal. Across its range, D. jeekeli shares this microhabitat with Tasmaniosoma compitale Mesibov, 2010 and T. hickmanorum Mesibov, 2010, both of which it resembles in having strong colouration, three transverse rows of low tubercles on metatergites, a cowl-like shield on the male gonopore and a gonopod telopodite tipped with a cluster of processes (Mesibov 2010). However, D. jeekeli is distinct from all 19 described species of Tasmaniosoma in the basal fusion of its telopodites and the unusual decoration of the solenomere.
description: Published as part of Mesibov, Robert, 2010, Two new millipede genera from northwest Tasmania, Australia (Diplopoda: Polydesmida: Dalodesmidae), pp. 53-61 in Zootaxa 2571 on pages 58-61, DOI: 10.5281/zenodo.197398