Lissodesmus piscator, Mesibov, Robert, 2019

Mesibov, Robert, 2019, A new and cryptic species of Lissodesmus Chamberlin, 1920 (Diplopoda, Polydesmida, Dalodesmidae) from Tasmania, Australia, ZooKeys 846, pp. 31-41 : 31

Lissodesmus piscator sp. nov. Figs 3, 4

Holotype.

AUSTRALIA • male; Tasmania, Central Plateau, Ritters Plain; [41.6824°S 146.3524°E]; 1080 m a.s.l.; 6 Mar. 2019; M. Driessen leg.; pitfall PU9 20 Feb.-6 Mar. 2019; coordinates are center of cluster of pitfall traps yielding L. piscator sp. nov. in 2017, 2018, 2019; coordinate uncertainty 75 m; QVMAG: QVM:2019:23:0015.

Paratype.

AUSTRALIA • male; same data as for holotype; dissected; QVMAG: QVM:2019:23:0016.

Other material.

5 males, 4 females and 1 stadium 7 female, same locality as holotype; see Supplement material 1 for details.

Diagnosis.

Distinguished from all other known Lissodesmus species by the form of the femoral process on the gonopod telopodite: the process has an erect, flattened, bluntly toothed distal branch and two large basal branches curving posteromedially across the posterior face of the telopodite.

Description.

Male/female approximate measurements: length 15/20 mm, midbody vertical diameter 1.3/1.6 mm, midbody width across paranota 1.7/1.7 mm. Colour in alcohol almost uniformly pale, antennae roseate (Fig. 3A).

Male with clypeus and frons moderately setose, vertex sparsely setose. Antennal sockets separated by ca. 2.5X socket diameter. Antenna short, just reaching ring 3 when manipulated backwards; relative length of antennomeres 6> (2,3)> (4,5), antennomere 6 widest. Head approx. as wide as tergite 4, cardines in dorsal view quadrate in outline; collum narrower than head and tergite 2; anterior collum margin gently convex, curvature extending smoothly to slightly convex lateral margin; posterior margin more or less straight; corners bluntly pointed. Tergite width increasing gradually from rings 2-6, then subequal, then decreasing 17-19. Waist pronounced (Fig. 3C), with faint longitudinal striations. Prozonites and metazonites with faint cellular sculpturing; limbus composed of narrow, distally tapered tabs. Paranota (Fig. 3C) smooth, narrow (ratio of overall width to prozonite width ca. 1.2 on midbody ring); anterior shoulder gently curving into slightly convex lateral margin, the latter with a small notch posteriorly and with short seta on anterior corner of notch; posterior corner upturned, extending just past posterior metatergite margin on most rings, usually with small subterminal seta; posterior corner seta prominent, erect (broken off on some rings). Ozopore small, round, opening dorsally close to paranotal margin and anterior to posterior corner; pore formula 5, 7, 9, 10, 12, 13, 15-19. Spiracles on diplosegments small, round, not emergent; rims slightly raised above pleural surface; posterior spiracle approx. midway between leg bases. Sternites approx. as long as wide, with short, sparse setae; transverse impression more pronounced than longitudinal. Legs short, ca. 0.9x as long as maximum ring diameter at midbody; legpairs 3-9 with prefemur slightly swollen dorsally; relative podomere lengths tarsus> (femur, prefemur)> (postfemur, tibia) on midbody legs; tarsus straight, ca. 1.3x as long as femur. From legpair 3, sphaerotrichomes on femur, postfemur, tibia and tarsus, densest on tibia and tarsus; sphaerotrichome numbers rapidly diminishing posteriorly but with a few sphaerotrichomes on tibia and tarsus of posterior legs; no sphaerotrichomes on last two legpairs; each sphaerotrichome hemispherical with tapering, blunt-tipped seta inclined distoventrally. Dense brush setae with slightly expanded tips on prefemur and femur of anterior legs; brush setae disappearing posteriorly. Pre-anal ring (Fig. 3D) with sparse, long setae; hypoproct trapezoidal, dorsal margin straight; epiproct extending past anal valves, tapering to truncate tip ca. 1/10 maximum width of ring 19; spinnerets in square array in shallow cavity just ventral to epiproct tip.

Gonopore small, opening mediodistally on only slightly enlarged leg 2 coxa. Bases of legs 6 and 7 well-separated by shallowly concave sternite, bases of legs 5 closer; brushes of sparse, long setae on sternites just medial to coxae of legs 5, 6, 7. Aperture ovoid, wider than long, ca. 1/2 width of ring 7 prozonite, rim slightly raised laterally and posteriorly.

Gonopods: Gonocoxae truncate-conical, lightly joined distomedially. Telopodite (Figs 3B, 4) slender, erect, extending to leg 5 bases when retracted; moderately setose on posterolateral surface from base to level of tibiotarsus origin. Solenomere (Fig. 4, s) slender, tapering, arising anteromedially at 1/3-1/2 telopodite height and terminating at ca. 3/4 telopodite height; directed posterodistally, slightly bent laterally at ca. 2/3 solenomere height, with small, medially directed, subapical tooth. Prostatic groove (Fig. 4, pg) running on anteromedial surface of telopodite to solenomere base, opening at solenomere tip. Tibiotarsus (Fig. 4, t) arising at ca. 1/2 telopodite height in large, anteromedial flange on telopodite; directed distolaterally above thickening on telopodite surface, slightly flattened anteroposteriorly, terminating in wide “Y” at level of subapical tooth on solenomere. Prefemoral process (Fig. 4, pf) tapering distally to bluntly rounded, posteriorly curved tip; subapically with posteroventral comb of 10-12 strong, well-spaced teeth; uncus (Fig. 4, u) at ca. 1/2 prefemoral process height, oblique, with small medial tooth; a small, sharp tooth on mediobasal surface of prefemoral process. Femoral process (Fig. 4, f) arising on anterolateral surface of prefemoral process, closely appressed to distal portion of latter; divided into erect distal branch, slightly expanded distally with small, blunt, marginal and submarginal teeth, the branch terminating just below level of prefemoral process tip; and 2 stout, well-separated basal branches curving posteriorly and medially, the most basal branch reaching and almost touching the solenomere tip, both branches with a few small teeth.

Female closely resembling male but stouter. Genital aperture with posterior margin gently convex medially; cyphopods not examined.

Name.

Latin piscator , fisherman, noun in apposition, for the type locality in the Fisher River catchment.

Distribution.

So far known only from Ritters Plain near Lake Mackenzie in northwest Tasmania (Figs 1B, 2). The Plain has a habitat area of ca. 100 ha and a known occupied area of less than 1 ha.