Nilotonia (Cookonia) avomonina, 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 : 56-58

Nilotonia (Cookonia) avomonina sp. nov.

( Figs 112–120 , Table 6)

Type: Holotype female, MD 106 a, Ankaratra (Antananarivo), Reserve Manjakatompo, Mont Ambohimirandrana , spring area exposition south-east (drainage Rivière Mahiavona), upper spring, 2350 m asl, 13.4 °C, 2 µS/cm, 07.10.2001, mounted.

Habitat: Spring at 2350 m asl.

Distribution: Madagascar (Central Highland – Ankaratra mountains).

Derivatio nominis: Avo (Malagasy) — high; monina (Malagasy) — to live; referring to the high elevation (highest sample site within the water mite samples from Madagascar) where the type locality (and only locality) is situated.

Diagnosis: Characters of the genus; integument lined; caudal and lateral margins of Cx-IV widely extended; postgenital sclerite widely extended, separated from secondary extension of Cx-IV by very narrow stripe of soft integument; Vgl-2 and -4 individually on large platelets; Cx-I medially approximate but not fused, Cx-III medially with slight secondary sclerotization, approximate to each other; genital field elongated trapezoid, acetabula mid-sized, elongated-oval, touching each other; sub-terminal seta on leg-IV-6 relatively short, inserted far proximal, not reaching distal tip of segment; capitulum stout, nearly rectangular; palp relatively slender, P1 without dorsal seta, P4 ventrally with small protrusion, P5 slender.

Description, female (n = 1): Idiosoma rounded-oval ( Fig. 112 ); dorsum mainly covered by large plate (L/ W 775/544), including Dgl-3 to -6, Lgl-4 and post-ocular setae, colour slightly dark-purple; lateral eyes small, oval, separated on both sides, lying free under integument; Dgl-1 far anterior; soft integument around dorsal plate lined, bearing slightly extended Dgl-2, Lgl-2 and l1-4; setae of Dgl-1, -3, -4 and -5 mid-sized, setae of other glandularia small ( Fig. 113 ); Lgl-1 fused with lateral secondary sclerotization of Cx-IV; Lgl-3 and l 5 in soft integument on ventral side, secondary sclerotization of Cx-IV forming a nearly closed, rounded ventral shield (L/W 706/755), extended also latero-dorsally of the Cx-I/II/III; Cx-I medially approximate, posterior half overlapping, but separated, postero-lateral margin of Cx-II lying over Cx-III, postero-medial margin of Cx-II lying under Cx-III; Cx-III medially approximate, medial margin of Cx-III extended by fine secondary sclerotization; suture line between Cx-III and Cx-IV incomplete, medially curved towards anterior, medial margin of Cx-IV straight to slightly concave, forming very narrow genital bay, caudal margin short, rounded, latero-caudal margin oblique towards anterior, insertion of leg-IV far anterior ( Fig. 112 ); medial and caudal margin of Cx-IV clearly visible, lateral margin unclear; setae at postero-lateral margin of Cx-I and medial margin of Cx-III/IV very small ( Fig. 112 ); genital bay narrow, approximate to genital field, formed by medial margins and caudal secondary sclerotization of Cx-IV as well as post-genital sclerite; genital flaps elongated, anteriorly and postero-laterally smoothly rounded, laterally nearly straight, broadened towards cauda; acetabula mid-sized, elongated-oval, slender, touching each other, Ac1 distant from anterior margin of genital flaps, Ac3 slightly distant from posterior margin; pre-genital sclerite triangular, laterally protruding genital flaps, post-genital sclerite large, greatly extended by secondary sclerotization, including setae of Vgl-1, forming caudal segment of ventral shield ( Fig. 112 ); Vgl-3 very close to caudal margin of Cx-IV, included in secondary sclerotization of Cx-IV; Vgl-2 and Vgl-4 on relatively large, irregular platelets; excretory pore without sclerotization ( Fig. 112 ); legs with several large setae; claws on leg-I to -III with one small dorsal and one larger ventral clawlet ( Figs 114, 115 ), leg-IV-6 distally tapering, with two small, peg-like terminal setae ( Fig. 116 ); capitulum very short, relatively high, dorsal and ventral margins nearly parallel ( Fig. 117 ); chelicera strong, proximally high, claw very heavy, dorso-distally serrate ( Figs 118, 119 ); palps slender, P1 without setae, P2 with one latero-ventral seta and six dorsal setae, ventral margin straight, P3 with one lateral and three dorsal setae, P4 distally curved, dorso-distal corner rounded, ventral setae slightly in distal half, ventral margin with slight protrusion, P5 slender, cone-shaped with long slender terminal claws ( Figs 117, 120 ).

Male: Unknown

Remarks: The two species of Cookonia are separated by the degree of fusion of their ventral shield (postgenital plate and Cx-IV fused in N. (Cookonia) anjozorobe , not fused in N. (Cookonia) avomonina ), the extent of the female dorsal plate (in N. (Cookonia) anjozorobe not including Dgl-6 and Lgl-4) and proportions of the palps and legs (slenderer in N. (Cookonia) avomonina ). A sexual dimorphism similar to N. (Cookonia) anjozorobe in the extent of the ventral shield (larger in male) is found in Bharatonia Cook, 1967 from India.

Figures

FIGURES 112–120. Nilotonia (Cookonia) avomonina subgen. et sp. nov., female holotype (MD 106a): 112, idiosoma, ventral view; 113, idiosoma, dorsal view; 114, leg-II; 115, leg-III-6; 116, leg-IV (first segment broken); 117, capitulum with left palp, lateral view; 118, left chelicera, lateral view; 119, right chelicera, medial view; 120, right palp, medial view. Scale bars = 100 µm.