Holostethus longosetis, Karg & Schorlemmer, 2011

Karg, W. & Schorlemmer, A., 2011, New Insights Into The Systematics Of Parasitiformes (Acarina) With New Species From South America, Acarologia 51 (1), pp. 3-29 : 14-17

Holostethus longosetis n. sp.

Holotype — ~ Ecuador, 1989.

Paratypes — 3 ~, 2 |, 1 ~ before hatching out of the deuto-nymph, 2 deuto-nymphs, 1 proto-nymph.

Etymology: longus = long, seta = hair, as to the relative long hairs on the dorsum.

Diagnosis — Most of dorsal setae nearly as long as the distances to the next setae in series, | first sternal seta shaped like a leaf, ~ digitus mobilis of chelicerae with one big proximal tooth and 11 – 12 small teeth, digitus fixus proximal 3 small, in the middle 3 bigger teeth, in front of it, 4 small and distal 4 – 5 very little teeth ( Figures 5 , 6 , 7 ).

Description — Idiosoma ~ 957 – 1092 x 650 – 696 µm.

Dorsum: Oval, brown, surface with net-like patterns, with 53 – 56 pairs of setae, by unpaired setae symmetry disturbed, most of setae 70 – 74 µm long, needle-like, posterior setae I4, Z3, Z4 and Z5 somewhat stronger, i1 = 70, i5 = 70, I1 = 70, I4 = 74, Z5 = 70 µm long, several setae on the anterior part shorter, z1 = 53, i2 = 63, r2 = 32, r3 = 52 µm long, at the vertex the anterior part of a marginal shield recognizable, the main part of this shield turned down to the venter.

Venter: Therefore marginal setae appear ventral, at the posterior part S5 (69 µm long) and I5 (60 µm long), ventral shields with net-like patterns, peritrematal shields well developed, peritremata reaching front margin of coxae I, remarkable big ventrianal shield with 20 pairs of setae and 4 – 5 unpaired setae, mostly 54-56 µm long, the paranal setae 60 µm long, between coxae III/IV the posterior margin of the sternogynial shield shaped like an inverted bell-jar, between coxae II a homogenous sternal shield with four pairs of sternal setae, st1 remarkably long: 46 µm, st2, st3 and st4 localised closely together forming the figure of a triangle, setae 27 – 30 µm long, sternal shield and sternogynial shield fused, between the sternogynial shield-part and coxae III/IV strip-like endopodal shields and small latigynial shields, each of these shields bearing 2 setae, between sternogynial shield and ventrianal shield a semicircular mesogynial shield, in front of the sternal-sternogynial shield a tritosternum with two laciniae and flanked by a pair of slen- der preendopodal shields.

Gnathosoma: Tectum tongue-like, hypostomatic groove slender, inside with 3 to 4 hypognathal transverse lines, outside on the palpal coxae 4 longer dented lines, setae on palpal coxae of different length, C1 = 44, C2 = 30, C3 = 60, C4 = 25 µm long, corniculi horn-like, laciniae with many fine fringes, a pair of stronger styli and a pair of longer points in the middle, digiti of chelicerae multidentate, palps: paraxial posterior part of palptrochanter swollen, anterior with 2 setae, 26 and 37 µm long, the longer setae slightly spatulate, most of the palp-setae needle-like, however inside 2 setae at the palp-genu (26, 28 µm long) and one seta at the palp-femur (36 µm long), pinnate.

Legs: I = 748, II = 609, III = 566, IV = 844 µm long if the idiosoma 1092 µm long, tarsus I with a pair of claws without pre-tarsus, tarsi II to IV with pretarsus and two claws.

Idiosoma | 957 – 1044 x 653 – 696 µm, dorsum similar as in the female, venter also with a big ventrianal shield, between coxae II, III and IV however a homogeneous sternum fused with the endopodal shields, a circular genital shield between coxae III, sternum with five pairs of setae, extraordinarily remarkable the first pair of sternal setae: leaf-like, 68 µm long and 26 µm wide, the other setae 27 – 28 µm long, digiti of the chelicerae with many teeth as in the female, outside the hypostomatic groove deviating from the ~ between C3 and C4 two areas densely covered with small teeth.

Idiosoma deuto-nymph 609 – 670 x 470 – 478 µm, dorsum and legs similar as in the female, venter also with a big ventrianal shield, between coxae II, III and IV however a homogeneous sternum fused with the endopodal shields bearing five pairs of needle-like setae, paranal setae are remarkably short: 14 µm, chelicerae as in the adults.

Idiosoma proto-nymph 435 x 390 µm, dorsum with lower number of setae as in the deuto-nymph, legs as in the other stages, sternum with three pairs of setae, ventrianal shield as in the other stages, peritremata very short.

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2011 Margotrichina

1 – Genua I – IV with four or fewer dorsal setae ( Edwards & Evans 1967, Krantz & Ainscough 1990), phoretic respectively parasitic stages with eu-anal setae ( Karg & Schorlemmer 2008)

2 – Tibia I – IV with three or more dorsal setae, femur IV of adults with six or seven setae, third hypostomatic setae well behind the second hypostomatic setae ( Karg 1989, Krantz & Ainscough 1990)

3 – In the larva, position of setae pair I3 on the dorsum marginal shifted ( Figure 8 ), dorsum of adults with marginal grooves ( Hirschmann & Zirngiebl-Nicol 1961, Karg & Schorlemmer 2008).

Figures

FIGURE 5: Holostethus longosetis n. sp. Female. a – Dorsum, 957 – 1092 µm long; b – Tectum, 88 µm wide.

FIGURE 6:: Holostethus longosetis n. sp. Female. a – Venter; b – Pedipalpus, 245 µm; c – Chelicera, 88 µm long.

FIGURE 7: Holostethus longosetis n. sp. a – Male Sternum, 350 µm long; b – Female Hypostome, 175 µm long.

FIGURE 8: Dorsum of larval stages in different groups of Margotrichina showing the shifting of setae I3, ancestrally caused by development of a special pygidial shield within the posterior rows of setae; a – Microgyniina, 220 µm; b – Uropodina, 250 – 380 µm; c – Ixodides, 500-600 µm long (after Hirschmann 1961 and Karg & Schorlemmer 2008).