Sandalodesmus joachimadisi Rojas-Buffet & Bouzan, n. sp.

Figs 1–5

Diagnosis. Males differ from all other species of the genus by the following combination of characters: prefemoral process (PfP) small, Z-shaped, twisted internally and directed parallel to acropodital branch (Figs 3A, 4A), prostatic groove (Pg) sinuous and S-shaped along the acropodite, ending upon an elongated prostatic apex (Figs 3A, 4A), acropodite process (Ap) broad and round, elongated, hood-shaped (Figs 3A–C, 4A–C), solenomere (S) apically curved, sickle-shaped (Figs 3A, 4A).

Name. The specific name is a patronymic in honor of the German ecologist and entomologist Joachim Ulrich Adis (1950–2007). He visited the Collection of Myriapoda of Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay in 2005 and suggested the need for the study of the underexplored Uruguayan Diplopoda .

Material examined.

Holotype: URUGUAY ● ♂; Valle del Lunarejo, Rivera, under cow dung, 31°11'23.7"S 55°54'04.2"W; 27.XII.2018; C. Rojas-Buffet leg.; FCE-Myr 0664.

Paratypes: URUGUAY ● 3 ♀♀; same data as for holotype; FCE-Myr 0664.

Additional material examined. All from URUGUAY ● 1 ♂; Tacuarembó Department, Tacuarembó city, urban zone, 31°44'18.9"S 55°58'46.7"W; 14.XI.2013; A. Laborda leg.; FCE-Myr 0556 ● 2 ♀♀; same locality, walking at night, 31°44'19.63"S 55°58'46.60"W; 27.XII.2018; D. Hagopián leg.; FCE-Myr 0665 ● 4 ♂♂, 3 ♀♀; Rivera Department, Sierra de la Aurora, under stones, 31°03'18.8"S 55°42'58.5"W; 10.I.1961; C. Carbonell and L.C. de Zolessi leg.; FCE-Myr 0354 ● 1 ♂, 1 ♀; Valle del Lunarejo, riparian forest, 31°11'27''S 55°56'20''W; 13.III.2019; C. Rojas-Buffet leg.; FCE-Myr 0768 ● 2 ♂♂, 3 ♀♀; same locality, under cow dung, camping zone, 31°11'18.8''S 55°54'19.1''W; 13.III.2019; C. Rojas-Buffet and M. Simó leg.; FCE-Myr 0769 ● 1 ♂; same locality, under cow dung, 31°10'21.5"S 55°54'49.4"W; 16.XI.2019; E. Lorier leg.; FCE-Myr 0770 ● 2 ♂♂; same locality, two meters from the stream, 31°10'23.0"S 55°54'06.7"W; 26.XI.2018; M.J. Albo leg.; FCE-Myr 0771 ● 13 ♂♂, 1 ♀; Salto Department, Olivera, grassland, collected in pitfall trap, 31°05'22.0"S 56°46'57.0"W; 10.XII.2019; G. Pompozzi leg.; FCE-Myr 0767.

Description. Male (holotype, FCE-Myr 0664). Coloration in life: head reddish. Antennae reddish brown with distal end of antennomers yellowish, antennomere seven completely yellow (Fig. 2D). Body reddish, with paranota tip yellowish and metazonites whitish at posterior border (Figs 1, 2A–C). Gnathochilarium (Fig. 2E, F): mentum (M) with smooth edges and small thick setae at central region; apical edge of stipes (S) and lingual lobes (L) with long and thin setae. Body rings: cuticle smooth; paranota with standard polydesmidan pore formula (5, 7, 9, 10, 12, 13, 15–19); paranota sub-triangular (Fig. 2A–C); ozopores (O) situated posteriorly (Fig. 2B, C). Stigma oval. Sternite 4 with a single pair of fused projections (P) (Fig. 2G). Other sternites without modifications (Fig. 2H). Anterior sternites covered with short and thick setae, posterior ones sparsely covered with thin setae. Leg pair 2 coxae each with a rectangular-shaped genital papilla. Walking legs reddish white-brown and without modifications (Fig. 1). Gonopod aperture on seventh body ring oval, posterior edge straight and without folds, but slightly elevated in anal view. Telson anteriorly reddish, posterior border yellowish (Fig. 2C).

Gonopods (Figs 3, 4): coxae (Cx) almost same length as telopodite, prominent in lateral view (Figs 3A–C, 4), with two anterior macrosetae (Figs 3B, 4B) and with a single, large and slender spiniform process (SpP) (Figs Total length (holotype, FCE-Myr 0664) (fragmented specimen): 39.8. Width: 4.47. Antennomere lengths (1 to 7): 0.42; 0.94; 0.93; 0.95; 0.97; 1.00; 0.24. Podomeres lengths of leg 10 (1 to 7): 0.49; 0.80; 1.53; 0.53; 0.63; 1.00; 0.30. Gonopod aperture: 1.0 long, 1.9 wide. Telson: 1.01 long. Gonopod: 1.69 long, 1.83 wide. Gonocoxae: 0.83 long, 1.09 wide. Telopodite: 1.57 long, 0.72 wide.

Female (paratype, FCE-Myr 0664). Coloration and body features as in male except that the coxae on body ring 3 with a small process. Posterior margin of vulvae aperture smooth, without projections. Vulvae (Fig. 3D) oval shaped in ventral view and elliptical shaped in lateral view. External and internal valves unequal in size, external valve (Ev) longer than internal valve (Iv), in ventral/distal view. Internal edges of both valves irregular in the medial portion. Both valves with scattered setae in comparison with operculum (Op). Operculum about 1/3 of the size of valves, typical for chelodesmids. Total length: 38.04. Width total: 4.95. Telson 1.3 long. Posterior margin of the vulvae aperture: 1.57 wide. Vulvae: 0.79 long, 0.55 wide. External valve: 0.72 long, 0.21 wide. Internal valve: 0.68 long, 0.31 wide. Operculum: 0.12 long, 0.31 wide.

Distribution. Northern Uruguay (Fig. 5).

Natural history. The species is usually associated with urban environments, such as built-up areas or camping areas. It can also be found in natural areas, such as riparian forest or grasslands. Specimens were found under stones, under decaying tree trunks, under cow dung, or walking on grass. Some specimens were found together in nests (Fig. 1B) that may have been built by the millipedes. Frequently more than one individual was found at the collection sites.