Sandalodesmus, Silvestri, 1902

Figueiredo, Thiago D., Iniesta, Luiz F. M., Brescovit, Antonio D. & Bouzan, Rodrigo S., 2025, Three new species of Sandalodesmus Silvestri, 1902 from the last intact stretches of Atlantic Forest in Brazil (Polydesmida: Chelodesmidae: Sandalodesmini), Zootaxa 5723 (4), pp. 514-532 : 530

Key to males of Sandalodesmus (based on gonopod structures)

Modified after Rojas-Buffet et al. (2022).

1 Acropodite process with long subtriangular secondary process laterally, about half length of prefemoral process; clearly separated from main process (see Hoffman 1982, fig. 1)....................................................... 2

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

2 Acropodite process rounded, curved mesad (see Bouzan et al. 2023, fig. 4A, C)............... S. araujoi ( Schubart, 1946)

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

3 Prefemorite short, less than half of telopodite length; not extending distad beyond base of prefemoral process............ 4

- Prefemorite long, more than half of telopodite length, extending distad to about mid-length of prefemoral process........ 12

4 Acropodite short, barely exceeding prefemoral process; solenomere projecting distally (see Schubart 1954a, fig. 16).................................................................................... S. camellatus (Schubart, 1954)

- Acropodite longer or equal to prefemoral process; forming a concave shield enclosing inner region.................... 5

5 Prefemoral process as long as acropodite; apically broad and rounded in mesal view; without basal lobe; acropodite with prominent lateral spiculate lobe (see Schubart 1958, fig. 4)............................. S. repandus ( Schubart, 1958)

- Prefemoral process shorter than acropodite ( Fig. 5A )......................................................... 6

6 Prefemoral process slender (see Schubart 1954b, fig. 14)...................................................... 7

- Prefemoral process broad ( Fig. 12D )...................................................................... 9

7 Prefemoral process small (1/3 of acropodite size), Z-shaped (see Rojas-Buffet et al. 2022, figs 3A, 4A)................................................................................. S. joachimadisi Rojas-Buffet & Bouzan, 2022

- Prefemoral process large, extending beyond half acropodite length.............................................. 8

8 Solenomere massive, apically reflexed; located near apical portion of acropodite region (see Hoffman 1982, fig. 5)....................................................................................... S. avilectus Hoffman, 1982

- Solenomere not massive; positioned near median portion of acropodite region (see Schubart 1954b, fig. 14)......................................................................................... S. iguazuensis (Schubart, 1954)

9 Acropodite hood-shaped, curved posteriorly beyond post-medial region; oriented almost parallel to gonocoxal axis ( Fig. 6D )............................................................................................... 10

- Acropodite straight; oriented nearly perpendicular to gonocoxal axis ( Fig. 10D )................................... 11

10 Cannula unmodified; acropodite with conspicuous median incision, in mesal view ( Fig. 5B )............ S. peruibe sp. nov.

- Cannula modified; without incision on acropodite (see Hoffman 1982, figs 3–4).............. S. liberellus Hoffman, 1982

11 Prefemoral process without indentations; solenomere exceeding acropodite process length ( Fig. 9B )....... S. jureia sp. nov.

- Prefemoral process with indentations; solenomere not exceeding acropodite process length ( Fig. 12D )... S. fandango sp. nov.

12 Acropodite with prominent deltoid laminate lobe on mesal side; prefemoral process straight (see Schubart 1956, fig. 3)... 13

- Acropodite with mesal lobe; prefemoral process rotated 180°, distal half opposite to basal half (see Schubart 1944, fig. 22).. .................................................................................................. 14

13 Deltoid mesal lobe apical, covering solenomere; solenomere exceeding apex of acropodite (see Schubart 1956, fig. 3)................................................................................. S. stramineus ( Schubart, 1956)

- Deltoid lobe subapical; solenomere visible, exceeding acropodite (see Hoffman 1967, figs 3–4; Hoffman 1982, fig. 11).................................................................................. S. schubarti ( Hoffman, 1982)

14 Solenomere with smooth outer edge (see Schubart 1944, fig. 22).......................... S. gasparae ( Schubart, 1944)

- Solenomere with denticulate outer edge................................................................... 15

15 Solenomere elongate (see Schubart 1944, figs 25, 26)............................... S. hippocampus ( Schubart, 1944)

- Solenomere short (see Schubart 1954a, fig. 14)..................................... S. paranaensis (Schubart, 1954)

Figures

FIGURE 5. Sexual characters of Sandalodesmus peruibe sp. nov. ♂ (IBSP 3741). A. left gonopod, ectal view. B. right gonopod (mirrored), mesal view. C. gonopod aperture, ventral view. D. apical region of acropodite, close-up, mesal view. Abbreviations: ap: acropodite process; asp: acropodite spiniform process; c: cannula; epfp: ectal projection of prefemoral process; gsp: gonopod spiniform process; mpfp: mesal projection of prefemoral process; pfp: prefemoral process; pfr: prefemoral region; s: solenomere. Scale bars: A, B. 1 mm; C. 2 mm; D. 500 μm.

FIGURE 6. Sexual characters of Sandalodesmus peruibe sp. nov. ♂ holotype (IBSP 401). A. left gonopod, ectal view. B. left gonopod, mesal view. C. left gonopod, ectal view. D. left gonopod, mesal view. Abbreviations: ap: acropodite process; asp: acropodite spiniform process; c: cannula; gcx: gonocoxite; pfp: prefemoral process; s: solenomere. Scale bars: A–D. 2 mm.

FIGURE 9. Sexual characters of Sandalodesmus jureia sp. nov. ♂ (IBSP 1127). A. left gonopod, ectal view. B. right gonopod (mirrored), mesal view. C. close-up of ectal side of the acropodite. D. left gonopod, anteroventral view. Abbreviations: ap: acropodite process; alp: acropodite laminar process; c: cannula; epfp: ectal projection of prefemoral process; mpfp: mesal projection of prefemoral process; pfp: prefemoral process; pfr: prefemoral region; s: solenomere. Scale bars: A, B. 500 μm; C. 50 μm.

FIGURE 10. Sexual characters of Sandalodesmus jureia sp. nov. ♂ holotype (IBSP 1300). A. left gonopod, ectal view. B. left gonopod, mesal view. C. left gonopod, ectal view. D. left gonopod, mesal view. Abbreviations: ap: acropodite process; alp: acropodite laminar process; c: cannula; gcx: gonocoxite; gsp: gonopod spiniform process; mpfp: mesal projection of prefemoral process; pfp: prefemoral process; s: solenomere. Scale bars: A–D. 1 mm.

FIGURE 12. Sexual characters of Sandalodesmus fandango sp. nov. ♂ holotype (IBSP 320). A. left gonopod, ectal view. B. left gonopod, mesal view. C. left gonopod, ectal view. D. left gonopod, mesal view. Abbreviations: ap: acropodite process; asp: acropodite spiniform process; c: cannula; gcx: gonocoxite; gsp: gonopod spiniform process; mpfp: mesal projection of prefemoral process; pfp: prefemoral process; pfr: prefemoral region; s: solenomere. Scale bars: A–D. 1 mm.