Riotintobolus makayi, Wesener, 2020

Wesener, Thomas, 2020, Ecotone shifts in southern Madagascar: first barcoding data and six new species of the endemic millipede genus Riotintobolus (Spirobolida, Pachybolidae), ZooKeys 953, pp. 1-29 : 1

Riotintobolus makayi sp. nov. Figure 10

Material examined.

1 ♂ holotype, ZFMK MYR7173, Madagascar, Province de Toliara, Makay Mts., forêt de galerie, 21°13'25.1"S, 045°19'36.0"E, 512 m, coll. Jean Noel, 29.xi.2010. Paratypes: 1 ♂, 1 ♀, ZFMK MYR939, Madagascar, Province de Toliara, Makay Mts., forêt de galerie, 21°13'27.5"S, 045°19'35.4"E, 531 m, coll. Jean Noel, 01.xii.2010.

Etymology.

Makayi, after the type locality, the area of Makay (Fig. 2 ). Noun in apposition.

Diagnosis.

R. makayi sp. nov. shares the flag-like membranous tip of the posterior gonopod with R. mandenensis , R. minutus , R. aridus , R. anomalus and R. antafoky sp. nov. Riotintobolus makayi sp. nov. shares the wide dorsal stripe, presence of tarsal pads on at least male legs 3-7, and a projecting epiproct only with R. mandenensis , R. minutus , and R. aridus . R. makayi sp. nov. differs from R. mandenensis and R. minutus in the configuration of the flag of the posterior telopod, which consists only of a single fold, while it has two folds in the latter two species. The curved lateral process and the freely ending efferent duct are unique characters for R. makayi sp. nov.

Description (based on male holotype): Measurements: Male holotype: 38+0 segments. Ca. 22 mm long (broken), 2.4 mm wide. Female paratype: 38+0 segments. Ca. 33 mm long (broken), 3.5 mm wide.

Colour (after ten years in ethanol): Head except for light clypeus black, body rings black, appendages red (Fig. 10A, B). Anterior margin of collum light brown. Dorsally with two wide light brown-reddish stripes, divided by a black stripe, all stripes even crossing the epiproct. Anal valves black, margin light brown, hypoproct light brown (Fig. 10C).

Head: each eye with 26-28 ommatidia in six rows. Incisura lateralis open (Fig. 10A). Labrum with standard three irregular teeth and a single row of 10-12 stout marginal setae. Clypeus with two setiferous foveolae on each side (Fig. 10B). Antennae short, protruding back to segment 3. Length of antennomeres: 1<2=3=4=5=6. Terminal antennomere with four large sensory cones located together inside a membranous area (Fig. 10B). Antennomere 5 and 6 latero-apically with sensilla basiconica.

Gnathochilarium: lamellae linguales each with two standard setae located behind one another. Stipites each with three apical setae. Endochilarium not dissected.

Mandible: Stipes without projection, well rounded (Fig. 10A, B). Gnathal lobe not dissected.

Collum: smooth, laterally not protruding as far as ring 2 (Fig. 10A).

Body rings: ozopores starting at segment 6, located slightly before, but touching suture between meso- and metazonite. Rings with smooth, but irregular coriaceous surface, ventrally on metazona with transverse ridges.

Telson: paraprocts with lips, abundant micropunctation especially towards edges (Fig. 10C). Epiproct well-rounded, reaching slightly above paraproct with a massive process (Fig. 10C). Hypoproct inconspicuous (Fig. 10C).

Legs: leg 1 with a large cylindrical coxa, twice as long as other podomeres. Tarsus with three pairs of ventral spines and an apical spine beyond claw. Leg 2 with an elongated coxa. Tarsus with two pairs of ventral spines and a short apical spine. Midbody legs with a rectangular coxa, as long as other podomeres. Each podomere ventrally with a single or a pair of apical setae, tarsus of leg 3- midbody with a tarsal pad, a single apical and three or four pairs of ventral spines (Fig. 10B). Legs on posterior part of body without a tarsal pad and two or three pairs of ventral spines. Length of midbody legs ca. 1.2 times body diameter in male.

Female sexual characters. No tarsal pads, antennae even shorter than male, only protruding back to collum. Female vulva simple, bivalve-like.

Male sexual characters: tarsal pads present from leg 3 to midbody (Fig. 10B). Coxae 3-7 without coxal processes (Fig. 10B).

Anterior gonopod sternite massive, elongated into a wide, well-rounded, triangular lobe (Fig. 10D). Sternite in anterior view well-visible, without discernible apodemes, protruding almost as high as coxal processes. Coxite with sharp triangular mesal process (Fig. 10D, E). Telopodite with slender process arising mesally (Fig. 10E), process apically curved with a strong triangular projection (Fig. 10D), tip well-rounded tip, protruding above lateral margin of telopodite (Fig. 10C).

Posterior gonopods consisting of two parts, separated by an articulation: a long coxite and a slightly shorter telopodite, efferent duct discharging apically (Fig. 10G). Process of coxite and telopodite standing in same axis (Fig. 10F, G). Pair of posterior gonopods located parallel to each other, connected by a small, sclerotised and visible sternite (Fig. 10G). Basal part of coxite wide, mesally with a triangular sclerite located on lower level than remaining part (Fig. 10G). Coxite elongated. Efferent duct running at mesal margin of coxite (Fig. 10F, G). Telopodite as wide as but slightly shorter than coxite, standing in same axis, apically with a membranous ‘flag’ (Fig. 10F, G). Laterally with sclerotised projection with a slender mesad-orientated branch (Fig. 10F, G). Membranous ‘flag’ longer than lateral process. Efferent duct ending freely, projecting above 'flag apically (Fig. 10F, G).

Comments.

this species lives in direct sympatry with Riotintobolus bovinus sp. nov. The female carried eggs in the body.

Figures

Figure 2. Distribution of the newly described Riotintobolus species, as well as of the still undescribed species. Vegetation marks modified from Moat and Smith 2007.

Figure 10. Riotintobolus makayi sp. nov., male holotype (ZFMK MYR 939) A multi-layer photograph, anterior body, lateral view B multi-layer photograph, leg pairs 1 - 7, ventral view C multi-layer photograph, posterior body end with telson D anterior gonopod, anterior view E anterior gonopod, posterior view F right posterior gonopod, anterior view G right posterior gonopod, posterior view. Abbreviations: Apo = apodeme; av = paraprocts; Co = collum (ring 1); Cx = coxite; Gn = gnathochilarium; Md = basal joints of mandible; Pre = epiproct; St = sternite; T = telopodite; x = lateral swollen process; y = opening of efferenct duct; z = apical membranous ' flag'; numbers refer to leg pair or segment number. Scale bars: 1 mm.