Noteremus summus Mesibov, 2009

Mesibov, Robert, 2009, A new millipede genus and a new species of Asphalidesmus Silvestri, 1910 (Diplopoda, Polydesmida, Dalodesmidea) from southern Tasmania, Australia, ZooKeys 7 (7), pp. 55-74 : 57-64

Noteremus summus Mesibov , sp. n.

urn:lsid:zoobank.org:act:57A5A291-5D11-4B78-833D-7AB5885C493D

Figs 1A , 2A, 3A, 3B, 4A, 4F, 5A, 5B, 6A, map Fig. 9 .

Holotype. Male. Australia, Tasmania, Mt Weld , 43º00’20”S 146º34’44”E ± 100m, 1300 m, pitfall WD1300P5L emptied 29 March 2001, N. Doran and R. Bashford, sample FT187, QVM 23 :46550.

Paratypes. 1 male, same details as holotype but WD1300P25L, FT188, QVM 23 :46551 ; 2 males, same details but WD1300P25U, 22 January 2002, FT5915, QVM 23 :46556 ; 1 male, same locality, 43º00’24”S 146º35’02”E ± 100m, 1200 m ,

WD1200P25U, 22 January 2002, same collectors, FT5909, QVM 23 :46555 ; 1 male, 2 females, same locality, 43º00’21”S 146º35’23”E ± 100m, 1100 m, WD- 1100P25U, 29 March 2001, same collectors, FT179, QVM 23 :46549 ; 1 male, same details but WD1100P45U, 26 April 2001, FT270, QVM 23 :46552 ; 1 male, same details but WD1100P5U, 18 December 2001, FT5812, QVM 23 :46553 ; 1 male, same details but WD1100P25U, FT5813, QVM 23 :45554 .

Diagnosis. Medium-sized (to ca 20 mm long), pigmented, surface-dwelling; midbody ring length to prozonite width ca 1.0; gonopod telopodite with two separate subterminal groups of pointed, rod-like structures on posteromedial surface near apex.

Description. Male/female approximate measurements: length 20/ 22 mm, maximum diameter 1.6/2.2 mm, maximum width across paranota 2.0/2.5 mm. Body colour faded in pitfall liquid and preservative, but better-preserved specimens are light reddish-brown grading to red anteriorly.

Male with head sparsely setose; antennal sockets slightly impressed, separated by ca 1.5X socket diameter. Antenna ( Fig. 2A ) slender, when manipulated reaching tergite 2; antennomere 6 widest; relative antennomere lengths 6>(2,3)>5>4. Head slightly wider than collum, slightly narrower than tergite 2; overall widths increasing slightly from rings 2 to 5, 6-16 more or less equal, 17 narrower. Ratio of ring length to prozonite width in midbody rings ca 1.0 ( Fig. 3A ). Collum from above with anterior and lateral margins nearly forming a semicircle, corners blunt, posterior margin with median half straight, lateral quarters obliquely joined to collum corners. Prozonites and metazonites smooth ( Figs 3A, 3B ); transverse furrow not distinguishable; waist pronounced, suture indistinct; a few very small setae posteriorly on metatergite. Limbus extremely small; tabs irregular in shape, ca 1-2 µm long. Paranota on rings 2-4 small, depressed, rounded anteriorly and posteriorly; ring 2 paranotum lower than collum and ring 3 paranotum; more posterior paranota expanded to rounded swellings at ring mid-height, tapering towards posterior corner. Ozopore small and round, opening dorsolaterally at about half ring height, close to posterior paranotal corner; pore formula 5, 7-18. Spiracle small, round, recessed, opening on short, widerimmed elevation; anterior spiracle on diplosegments opening just above and anterior to anterior leg base, posterior spiracle above and about midway between leg bases. Sternites longer than wide, very sparsely setose, longitudinal and transverse impressions well-defined. Pre-anal ring with a few setae; epiproct broadly rounded, only slightly extending past anal valves; hypoproct trapezoidal. Ventral spinnerets ca 2.5X further apart than dorsal spinnerets ( Fig. 4A ); spinneret seta set in thin, closely fitting sheath with irregular margin. Anterior legs ( Fig. 2A ) a little swollen with prefemur and femur somewhat expanded dorsally, tarsus straight, claw small; relative podomere lengths tarsus>femur>prefemur>(postfemur, tibia). No sphaerotrichomes; brush setae on prefemur, femur, postfemur, tibia; brush setae unbranched with tapered tips. Gonopore small, round, on distomedial projection of leg 2 coxa. Bases of legpairs 5, 6, 7 separated to accommodate retracted gonopods, legpair 5 bases less so; small, paired, conical projections on sternal portion of legpair 4 bases, each projection tipped with small brush of setae ( Fig. 4F ).

Gonopod aperture about one-third prozonite width, rhomboid with long anterior edge close to anterior prozonite margin; posterior rim of aperture slightly raised. Gonocoxae small, short, tapering distally, concave mediobasally, weakly joined mediodistally. Cannula prominent, inserting in shallow depression on basal surface. Telopodites separate, reaching to legpair 4 bases when retracted. Telopodite ( Figs 5A, 5B , 6A ) thin, straight, unbranched, with flared base and equally expanded apex. Solenomere a short, acuminate process on medial side of telopodite apex. Prostatic groove bending anteriorly in flared telopodite base, then posterodistally and running more or less directly to solenomere on medial side of telopodite. Telopodite with numerous short, very fine setae at base near cannula insertion; a few longer setae on posterolateral surface close to base; and two closely packed groups of pointed, rod-like structures at or near the apex: a distal row extending distolaterally to a small cluster, and two separate posteromedial clusters at either end of a short, low posteriormedial ridge near the telopodite apex.

Female ( Fig. 1A ) larger than male, anterior legs not swollen; posterior margin of epigynum produced medially as narrow, round-tipped projection, just reaching beyond leg 2 coxae ventrally; cyphopods not examined.

Distribution and habitat. So far known only from grassland, scrub and subalpine woodland on the summit of Mt Weld, southeast Tasmania, from 1100 to 1300 m elevation ( Fig. 9 ).

Etymology. Latin summus (‘highest’), adjective, nominative singular, for its occurrence on a mountain summit.

Remarks. N. summus is the largest H+19 polydesmidan in Tasmania. The next largest species, an undescribed species of Tasmaniosoma Verhoeff, 1936 , has a maximum diameter in females of less than 1.5 mm, compared to 2.2 mm in N. summus .

All specimens are from 2001-2002 invertebrate sampling on the Mt Weld altitudinal transect. The transect was a satellite project of the International Biodiversity Observation Year and was established and sampled by Forestry Tasmania and the Tasmanian Department of Primary Industries and Water. At the 1100, 1200 and 1300 m sites, six weather-protected pitfall traps (ca 400 mL capacity, ca 90 mm top diameter, filled either with undiluted ethylene glycol or the same plus 5% glycerol) were left open for about four weeks every month in the austral summer. Site details and transect history are given in Grove (2004).

At 1100 to 1300 m on Mt Weld, N. summus co-occurs with the polydesmidans Atalopharetra bashfordi Mesibov, 2005 , A. johnsi Mesibov, 2005 , Atrophotergum montanum Mesibov, 2004 , Paredrodesmus bicalcar Mesibov, 2003 and an undescribed species of Tasmaniosoma (specimens in Mt Weld transect samples in QVM).

Figures

Figure 1. (A) Noteremus summus sp. n., paratype female, QVM 23:46549; (B) N. infimus sp. n., paratype female, QVM 23:12339. (C), (D) Asphalidesmus golovatchi sp. n.: (C) Partly curled paratype male, QVM 23:46402; (D) anterior view of ring 6, paratype male, QVM 23:46560. Scale bars: (A), (B) = 2.5 mm, (C) = 1.0 mm, (D) = 0.5 mm.

Figure 2. Antenna and leg 6 of paratype males. (A) Noteremus summus sp. n., QVM 23:46549; (B) N. infimus sp. n., QVM 23:12339; (C) Asphalidesmus golovatchi sp. n., QVM 23:46560. Scale bars: (A), (B) = 0.5 mm, (C) = 0.1 mm. Setae and antennal cones not shown.

Figure 3. Dorsal view of ring 12 and left lateral view of ring 13 of paratype males. (A), (B) Noteremus summus sp. n., QVM 23:46556; (C), (D) N. infimus sp. n., QVM 23:12969. Scale bars = 0.5 mm.

Figure 4. (A)-(D) Spinnerets, posterior view. (A) Noteremus summus sp. n., paratype male, QVM 23:46556; (B) N. infimus sp. n., paratype male, QVM 23:12969; (C) Paredrodesmus taurulus, male, QVM 23:46313; (D) Procophorella innupta, male, QVM 23:25456. (E) N. infimus sp. n., head of male from Growling Swallet cave, QVM 23:12118. (F) N. summus sp. n., paratype male, QVM 23:46556, posterior view of ring 5 showing legpair 5 bases (foreground) and legpair 4 bases (background). Scale bars: (A)-(D) = 0.05 mm; (E), (F) = 0.25 mm.

Figure 5. Gonopods of paratype males in situ; lower images are enlargements of upper images. (A), (B) Noteremus summus sp. n., QVM 23:46556; (C), (D) N. infimus sp. n., QVM 23:12969. Scale bars: (A), (C) = 0.5 mm; (B), (D) = 0.1 mm.

Figure 6. Right gonopod of paratype males. (A) Noteremus summus sp. n., QVM 23:46549, medial view. (B), (C) Asphalidesmus golovatchi sp. n., QVM 23:46560; (B) medial and slightly posterior view, (C) anterior view. Scale bars = 0.25 mm. Dashed lines indicate course of prostatic groove.

Figure 9. Localities as of 1 January 2009 for Noteremus summus sp. n. (Ɨ), N. infimus sp. n. (·) and Asphalidesmus golovatchi sp. n. (Δ). Scale bar = 25 km; grey lines are 100 m elevation contours. Town abbreviations: M = Maydena, G = Geeveston, S = Southport. Inset: map of Tasmania showing location of main map (rectangle).