Autostreptus Silvestri, 1905

Parra-Gómez, Antonio, Iniesta, Luiz F. M. & Morales, Jesús A., 2025, Revisiting the poorly known Chilean genus Autostreptus Silvestri, 1905 (Diplopoda, Spirostreptida, Spirostreptidae) with the description of a new species, European Journal of Taxonomy 1004, pp. 237-258 : 239

Genus Autostreptus Silvestri, 1905

Autostreptus Silvestri, 1905: 742 .

Type species: Iulus (recte: Julus ) chilensis Gervais, 1847 , by monotypy.

Diagnosis

Modified after Demange & Silva (1971: 709). Species of Autostreptus differ from other Spirostreptidae by the combination of the following characters: anterior margin of collum unmodified, not thickened ( Figs 4A , 8C ); body rings mostly smooth. Prefemoral process (pfp) of first pair of male legs prominent ( Figs 5A , 7A , 9A ). Gonopods with proplica (pp) subrectangular ( Figs 5C , 7C , 9C ); metaplica (mp) with mesoapical process (map) prominent; lateroapical metaplical process (dmp) elongated, directed ectad ( Figs 5C–D , 7C–D , 9C–D ). Telopodite (tp) with lamellar expansion (ltp); seminal groove (sg) running along ectal margin of ltp; long, pointed antetorsal process (atp) ( Figs 5C, E , 7C, E , 9C, E ); tip of telopodite (tp) not branched, solenomere (sl) acuminated, partially covered by ltp ( Figs 5F , 7F , 9F ).

Distribution

Known from Canela in Coquimbo Region to Constitución in Maule Region, Chile.

Composition

Autostreptus chilensis ( Gervais, 1847) , A. yanezi Demange & Silva, 1971 , and A. silvagonzalezi sp. nov.

Remarks

While Spirostreptidae is well-defined morphologically within Spirostreptida , its internal classification remains uncertain as a result of the lack of phylogenetic studies. A preliminary subdivision was suggested by Enghoff (2023), carefully organizing the family into five tribes: Spirostreptini Brandt, 1833 (African genera); Trachystreptini Cook in Cook & Collins, 1895 (African genera); Orthogoneptini Chamberlin, 1941 (American genera); Perustreptini Verhoeff, 1941 (African and America genera); and Metriostreptini Krabbe, 1982 (African genera). Here, we follow this intrafamilial organization, discussing below the position of the Chilean Autostreptus .

Figures

Fig. 4. Autostreptus chilensis (Gervais, 1847), ♂ (PG-34-VAL, MNHNCL). A. Head, collum and anterior rings, lateral view. B. Posterior rings and telson, lateral view. C. Antenna. D. Midbody ring in posterior view. Scale bars: A = 0.9 mm; B = 1 mm; C = 0.6 mm; D = 0.7 mm.

Fig. 8. Autostreptus silvagonzalezi sp. nov., holotype, ♂ (MNHNCL 8449). A. Gnathochilarium, ventral view. B. Antenna. C. Head, collum and anterior rings, lateral view. D. Posterior rings and telson, lateral view. Scale bars: A = 0.8 mm; B = 0.5 mm; C = 1.4 mm; D = 1.5 mm.

Fig. 5. Autostreptus chilensis (Gervais, 1847), male sexual characters. A, C–E. PG-34-VAL (MNHNCL). B, F. e-8 (MNHNCL). A. First leg-pair, anterior view. B. Second leg-pair, posterior view. C–F. Left gonopod. C. Anterior view. D. Posterior view. E. Lateral view. F. Detail of the distal region of telopodite, lateral view (arrow indicating the protruding serrated zone). Abbreviations: atp = antetorsal process of telopodite; dmp = distolateral metaplica process; ltp = lamellar expansion of telopodite; map = mesoapical metaplica process; mp = metaplica; pfp = prefemoral process of first male leg-pair; pn = penes; pp = proplica; px = paracoxite; sg = seminal groove; sl = solenomere; tp = telopodite. Scale bars: A, F = 0.6 mm; B = 0.5 mm; C = 0.8 mm; D = 1 mm; E = 1.2 mm.

Fig. 7. Autostreptus yanezi Demange & Silva, 1971 (e-57, MNHNCL), male sexual characters. A. First leg-pair, anterior view. B. Second leg-pair, posterior view. C–F. Left gonopod. C. Anterior view (detail of arrow indicating the mesoapical dentiform process on proplica). D. Posterior view. E. Lateral view. F. Detail of distal region of telopodite, medial view (arrow indicating bifurcated process). Abbreviations: atp = antetorsal process of telopodite; dmp = distolateral metaplica process; ltp = lamellar expansion of telopodite; map = mesoapical metaplica process; mp = metaplica; pfp = prefemoral process of first male leg-pair; pn = penes; pp = proplica; px = paracoxite; sg = seminal groove; sl = solenomere; tp = telopodite. Scale bars: A–B = 0.5 mm; C–E = 0.7 mm; F = 0.3 mm.

Fig. 9. Autostreptus silvagonzalezi sp. nov., holotype, ♂ (MNHNCL 8449), sexual characters. A. First leg-pair, anterior view. B. Second leg-pair, posterior view. C–F. Left gonopod. C. Anterior view. D. Posterior view. E. Lateral view. F. Detail of distal region of telopodite, posterior view. Abbreviations: atp = antetorsal process of telopodite; dmp = distolateral metaplica process; ltp = lamellar expansion of telopodite; map = mesoapical metaplica process; mp = metaplica; pfp = prefemoral process of first male leg-pair; pn = penes; pp = proplica; px = paracoxite; sg = seminal groove; sl = solenomere; tp = telopodite. Scale bars: A, E = 0.6 mm; B–C, F = 0.5 mm; D = 0.7 mm.