Sandalodesmus, Silvestri, 1902

Rojas-Buffet, Carolina, Bouzan, Rodrigo Salvador, Sierwald, Petra, Brescovit, Antonio Do- Mingos & Simó, Miguel, 2022, Sandalodesmus joachimadisi n. sp., the first Chelodesmidae member from Uruguay with an updated key to species of the genus (Diplopoda: Polydesmida), Zootaxa 5150 (2), pp. 260-268 : 266

Key to males of Sandalodesmus (based on gonopod structures)

1 Acropodite process with a prominent, subtriangular secondary process on the lateral side............................ 2

- Acropodite process without a secondary process............................................................ 3

2 (1) Acropodite process rounded, curved mesad (see Schubart 1946, fig. 4)..................... S. araujoi ( Schubart, 1946)

- Acropodite process subtriangular, projected up (see Silvestri 1895, fig. 3; Hoffman 1982, figs 1, 2)................................................................................................. S. salvadorii ( Silvestri, 1895)

3 (1) Prefemur short, less than half of the total length of telopodite, not extending distad beyond base of the prefemoral process.. 4

- Prefemur longer, more than half of the total length of telopodite, extending distad to about midlength of prefemoral process.. ................................................................................................... 9

4 (3) Acropodite short, scarcely longer than prefemoral process, its distal edge exceeded by solenomere (see Schubart 1954a, fig. 16) …......................................................................... S. camellatus (Schubart, 1954)

- Acropodite long, forming a concave shield that contains the solenomere......................................... 5

5 (4) Prefemoral process shorter than acropodite................................................................. 6

- Prefemoral process as long as acropodite, apically broad and rounded in mesal aspect, without a basal lobe; acropodite with a prominent spiculate lobe on the lateral side (see Schubart 1958, fig. 4).................... S. repandus ( Schubart, 1958)

6 (5) Nontorsate prefemoral process.......................................................................... 7

- Torsate prefemoral process............................................................................. 8

7 (6) Solenomere massive and apically reflexed (see Hoffman 1982, fig. 5)...................... S. avilectus Hoffman, 1982

- Solenomere not massive (see Schubart 1954b, fig. 14)............................... S. iguazuensis (Schubart, 1954)

8 (6) Prefemoral process large, concave, excavated to accommodate the acropodite (see Hoffman 1982, figs 3, 4)............................................................................................ S. librellus Hoffman, 1982

- Prefemoral process small, Z-shaped ( Figs 3A , 4A ).............................. Sandalodesmus joachimadisi n. sp.

9 (3) Acropodite with a prominent laminate deltoid lobe on the mesal side; prefemoral process straight.................... 10

- Acropodite with a lobe on the mesal side; prefemoral process rotated 180° so that the distal half is on the opposite side from the basal half.......................................................................................... 11

10 (9) Mesal deltoid lobe of acropodite placed apically and concealing solenomere, latter extending beyond end of acropodite (see Schubart 1956, fig. 3)......................................................... S. stramineus ( Schubart, 1956)

- Mesal deltoid lobe of acropodite placed subapically, solenomere entirely visible and extending beyond end of acropodite (see Hoffman 1967, figs 3, 4; Hoffman 1982, fig. 11)..................................... S. schubarti ( Hoffman, 1967)

11 (9) Outer edge of solenomere entire, smooth (see Schubart 1944, fig. 22).................... S. gasparae ( Schubart, 1944)

- Outer edge of solenomere denticulate..................................................................… 12

12 (11) Solenomere elongate, the seminal groove sinuately curved (see Schubart 1944, figs 25, 26).................................................................................................... S. hippocampus ( Schubart, 1944)

- Solenomere short, the seminal groove arcuately curved (see Schubart 1954a, fig. 14)...... S. paranaensis (Schubart, 1954)

Figures

FIGURE 3. Sexual characters of Sandalodesmus joachimadisi n. sp. A. Holotype ♂ (FCE-Myr 0664), left gonopod, mesal view. B. Holotype ♂ (FCE-Myr 0664), left gonopod, lateral view. C. Holotype ♂ (FCE-Myr 0664), left gonopod, ventral view. D. Paratype ♀ (FCE-Myr 0664), left vulva, ventral view. Abbreviations: Ap: acropodital process; Ca: cannula; Cx: coxa; Ev: external valve; Iv: internal valve; Op: operculum; Pf: prefemur; PfP: prefemoral process; Pg: prostatic groove; S: solenomere; SpP: spiniform process. Scale bars: 0.5 mm (A–C), 0.2 mm (D). Photographed by: Damián Hagopián.

FIGURE 4. Gonopod drawings of Sandalodesmus joachimadisi n. sp., holotype ♂ (FCE-Myr 0664), left gonopod. A. Mesal view. B. Lateral view. C. Ventral view. Abbreviations: Ap: acropodital process; Ca: cannula; Cx: coxa; Pf: prefemur; PfP: prefemoral process; Pg: prostatic groove; S: solenomere; SpP: spiniform process. Scale bars: 0.5 mm.