Paratetrahygrobatella, Tuzovskij, Petr V. & Stolbov, Vitaly A., 2016

Tuzovskij, Petr V. & Stolbov, Vitaly A., 2016, Description of a new hygrobatid genus from Chile (Acari, Hydrachnidia: Hygrobatidae), Zootaxa 4161 (4), pp. 579-585 : 579-580

Paratetrahygrobatella n. gen.

Type species. Paratetrahygrobatella magellanica sp.n.

Diagnosis. Capitulum free and without anchoral process, coxal plates in four groups in both sexes; coxal plates IV triangular, suture line between coxal plates III- and IV solid in both sexes, degree of secondary sclerotization of idiosoma variable, with large dorsal shield in males and some pairs of small dorsal platelets in females; lateral eyes not in capsules, eye pigment present; with sexual dimorphism of genital field and pedipalp; P-2 and P-3 ventrally denticulate, P-2 with ventro-distal projections in males and without ventro-distal projections in females; three pairs of genital acetabula, lying on two plates in females, these plates fused into a large triangular plate including as well the excretory pore males; legs without swimming setae, I–III-Leg-1 with long disto-lateral seta.

Etymology. The generic name is derived from para and the genus name Tetrahygrobatella .

Remarks. The new genus is similar to Tetrahygrobatella Lundblad, 1953 but differs in the following characters (character states of Tetrahygrobatella given in parenthesis, data from Cook 1974, 1980, 1988): Male: the coxal plates in four groups, the interspace between coxal groups and genital field with soft integument, Fig. 14 (ventral side with large shield including all coxal plates and genital field), the coxal plates IV triangular (trapezoidal), the capitulum free (laterally free but fused with the ventral shield posteriorly); pedipalp with sexual dimorphism, Figs. 7 , 20 (without sexual dimorphism), the genital field is free and triangular (more or less circular and fused with the ventral shield), the gonopore and excretory pore located close to each other (separated). Female: the dorsal surface with one pair of relatively large anteromedial plates and four pairs of small platelets, Fig.1 (with a single pair of anteromedial plates); the suture line between coxal plates III and IV is solid and not producing Y-shaped suture, Fig. 2 (usually producing Y-shaped suture).

The combination of the genital field and coxal plates IV in the male of this new genus are rather unique within the family Hygrobatidae . The triangular shape of the posterior coxal plates is similar to those of some representatives of the family Limnesiidae ( Limnesia Koch, 1836 ; Mixolimnesia Cook, 1988 ; Protolimnesia Lundblad, 1927 , etc.).

Figures

FIGURES 13 – 14. Paratetrahygrobatella magellanica sp. n., male: 13, dorsal view (holotype); 14, ventral view (paratype). Scale bars: 13 = 100 µm, 14 = 200 µm.

FIGURES 3 – 7. Paratetrahygrobatella magellanica sp. n., female: 3, genital field; 4 – 5, genital plate (paratypes); 6, chelicera, lateral view; 7, pedipalp lateral view. Scale bars: 3 – 6 = 100 µm, 7 = 50 µm.

FIGURES 18 – 20. Paratetrahygrobatella magellanica sp. n., male (holotype): 18, leg IV; 19, claw of leg IV; 20, pedipalp (lateral view). Scale bars: 18, 20 = 100 µm, 19 = 50 µm.

FIGURES 1 – 2. Paratetrahygrobatella magellanica sp. n., female: 1, dorsal view; 2, ventral view. Scale bar: 200 µm.