Nilotonia (Dartonia) nifymanana, Goldschmidt, 2008

Goldschmidt, Tom, 2008, Taxonomical, ecological and zoogeographical studies on anisitsiellid water mites (Acari: Hydrachnidia: Anisitsiellidae Koenike, 1910) from Madagascar, Zootaxa 1954 (1), pp. 1-120 : 21-26

Nilotonia (Dartonia) nifymanana sp. nov.

(Figs 28–40 (41, 42), Table 3)

Type: Holotype female, MD 20 b, Ionilahy (Fianarantsoa), first left tributary of Rivière Ionilahy upstream railroad bridge to Manakara , pool, 200 m asl, 23.5 °C, 88 µS/cm, 11.08.2001, mounted.

Additional specimens examined: MD 118b, Maromandia (Majunga), left tributary of Rivière Andranamalaza, pool, about 1.0 km east from main road, 100 m asl, 25.5 °C, 36 µS/cm, 21.10.2001, 1/1/0 mounted.

Habitat: Streams at 100–200 m asl.

Distribution: Madagascar (Eastern and North-western lowland).

Derivatio nominis: Nify (Malagasy) — tooth, manana (Malagasy) — bearing; referring to the dense field of characteristic denticles the species bears on the ventral surface of P2.

Diagnosis: Dorsum according to the ‘groundplan’ of the genus; integument coarsely lined; venter nearly without secondary sclerotization (only small area at medial margin of Cx-III); Cx-I and Cx-II medially not fused, suture between Cx-III and Cx-IV incomplete; genital field large, acetabula large, oval-rounded, Ac3 round; posterior genital sclerite small; legs bearing many heavy setae; leg-I to -III with claws, bearing ventrally serrate clawlets, leg-IV distally with two long sub-terminal setae, no sexual dimorphism in the legs; palp compact, P2 medio-ventrally with a dense field of denticles.

Description, female (n = 2): Idiosoma relatively large (L/W 775 (746)/608 (559)); integument dorsally and ventrally coarsely lined; posterior dorsal plate small (L/W 132 (123)/110 (105)), nearly rounded, anterior dorsal platelets small (L/W 47 (40)/34 (32)), oval, one pair of knob-like sclerites anterior to posterior plate, one knob-like sclerite anterior to each anterior platelet; Dgl-1 with very strong, pinnate setae, Dgl-2 and -6 with smaller setae, Dgl-3 to -5 with stronger setae; lateral eyes free under the integument, relatively far separated from each other on each side, anterior eye postero-lateral to Dgl-1, posterior eye postero-lateral to Dgl- 2, accompanied by a bowl-shaped sclerite, l1 caudal to posterior eye (Fig. 29); Cx-I elongated, medial margin long (L 135 (118)), clearly separated, lateral margin lying over Cx-II, Cx-II postero-laterally lying over Cx- III; Cx-IV relatively small, medial margin of Cx-III/IV relatively straight, oblique, with very small secondary sclerotization, caudal margin of Cx-IV transverse (perpendicular to medial line), medial with a clear corner; Cxgl-2 partly under the posterior margin of Cx-II, fused with Cx-III, Cxgl-4 postero-median, closely approached to the anterior margin of Cx-III (Fig. 28); genital field anterior close to coxal field, genital flaps large, elongated, nearly straight, posteriorly tapering; acetabula large, touching each other, Ac1 and Ac2 oval (in the specimen drawn in Fig. 28, the left Ac1 is split into two acetabula), Ac3 rounded; anterior genital sclerite broad crescent shaped, posterior genital sclerite small, caudal margin straight, submerged under genital field (Fig. 28); excretory pore without sclerotization; Vgl on small platelets (Fig. 28); legs strong, bearing many large setae (several pinnate); leg-I to leg-III terminate in strong claws with one dorsal and about six ventral comb-like clawlets (Fig. 30), leg-IV-6 distally pointed (variable, see Figs 32, 33), with two large, pinnate sub-terminal setae (Figs 31–33); capitulum compact, rostrum short, chelicera caudally tapering (Fig. 34), palps relatively short, compact, P1 with one dorsal seta, P2 very stout, dorsally bearing six strong, pinnate setae, medio-ventrally with a dense field of denticles, latero-ventrally with a long seta, P3 with 3 dorsal and one ventro-lateral setae, ventral margin curved, P4 relatively compact, with ventral setae on clear protrusions (Figs 34, 35).

Male (n = 1 (juvenile)): Genital field more compact, less extended beyond caudal margin of coxal field, Cx-IV closer approached to genital field ( Fig. 36 ); genital skeleton compact (slightly distorted in preparation, Fig. 37 ), brachia distalia and proximalia strong, brachia proximalia long and slender, carina anterior and posterior distinct, short and high ( Fig. 37 ); legs as in female ( Figs 38, 39 ); capitulum as in female, P2 more slen- der ( Fig. 40 ).

Remarks: Nilotonia (Dartonia) nifymanana sp. nov. is separated from Nilotonia (Dartiella) ivelany and Nilotonia (Dartiella) onilahy in the very small dorsal plate and platelets, the coarse lined integument, the more compact palps (especially the expanded P2 with ventral denticles), the leg claws (with comb-like ventral clawlets) and the two long, sub-terminal setae on leg-IV-6. The character state of an incomplete suture between Cx-III and Cx-IV and claws on leg-I to -III with serrate ventral clawlets is shared with two North African ( N. (Dartiella) parva ( Walter, 1931) and longipora ( Walter, 1925)) and three East African species ( N. (Dartiella) robusta ( Walter, 1931) , thermophila ( Lundblad, 1951) and micropora ( Walter, 1939)). Nilotonia

( Dartiella ) micropora is separated from all other African (and Malagasy) species due to its very small acetabula ( Walter 1939). Nilotonia (Dartiella) parva is very similar to N. (Dartiella) robusta , however N. parva is smaller and the integument is more densely lined. Both North African species bear more slender palps than N. (Dartonia) nifymanana ; furthermore, N. (Dartiella) parva does not bear any large setae (terminal or sub-terminal) on leg-IV-6 and all acetabula are elongated-oval; in N. (Dartiella) longipora , the acetabula are much smaller and more slender ( Walter 1925, 1931). N. (Dartiella) thermophila bears only very small denticles on the ventral surface of P2 and only small comb-like ventral clawlets on leg-I to -III, in N. (Dartiella) robusta and N. (Dartonia) nifymanana these two characters are strongly developed. In N. (Dartiella) robusta and thermophila the genital field is smaller and not as close to the coxal field, than it is in N. (Dartonia) nifymanana ; additionally, in these species the acetabula are smaller and all of equally oval shape, whereas in N. (Dartonia) nifymanana Ac 3 is rounded. Finally, the most similar East African species, N. (Dartiella) robusta , is separated from the new species from Madagascar by its slightly more slender palps (especially P2 and P4); a wider, crescent-shaped posterior genital sclerite (in N. (Dartonia) nifymanana it is small and straight); smaller dorsal platelets ( Fig. 41 ); and slenderer distal segments of leg-IV as well as only one large sub-terminal seta on leg-IV-6 ( Fig. 42 ).

Figures

FIGURES 36–40. Nilotonia (Dartonia) nifymanana sp. nov., male (MD 118b): 36, genital field, ventral view; 37, genital skeleton, antero-lateral view; 38, leg-IV-6, anterior view; 39, leg-IV-6, posterior view; 40, right palp, medial view. Scale bars = 100 µm.

FIGURES 41, 42. Nilotonia (Dartiella) robusta (Walter, 1931), male (NRM 3825): 41, idiosoma, dorsal view; 42, leg- IV (1. segment broken). Scale bars = 100 µm.