Armascirus brasiliensis Den Heyer

Heyer, Jacob Den & Castro, Tatiane Marie Martins Gomes De, 2012, New Neotropical cunaxine species (Acari: Prostigmata: Cunaxidae), Zootaxa 3265, pp. 22-42 : 24-29

Armascirus brasiliensis Den Heyer sp. nov.

Material examined: 1 female holotype, 1 male paratype, sunflower ( Helianthus annuus L.) residue, Department of Entomology, Phytopathology and Agricultural Zoology, Escola Superior de Agricultura ʺLuiz de Queirozʺ( ESALQ), University of São Paulo, Piracicaba-SP., Brazil, 14-XI-2007, J. Den Heyer.

Description.

Female ( Figs. 1–7 ). Dimensions. Idiosoma : length 593, width 400; length hypognathum 293; width hypognathum 123; length palp 400–404; length chelicera 254–258; length legs I 520–527; II 454–485; III 531–551; IV 610–581; length sensillae: vi 327–346, sce 504–514

Dorsum ( Fig. 1 a). The propodosoma is provided with an externally reticulate shield carrying short st-setae ve and sci as well as finely setose sensillae vi and sce ( Figs 1 c & 1d); the latter is the longer. The hysterosoma features 3 shields, 1 median shield carrying st-setae d1 and laterally, medially to setae c2, a small shield; all being reticulate. Setae f1 are the longest dorsal st-setae. Integumental striae dense and papillate.

Venter ( Fig. 1 b) The coxal regions form two groups on either side; coxae I and II form one group, III and IV the other. Coxae seta formula is 3 – 2 – 3 – 2. The propodogastral setae occur medially just posteriad coxae II. Paracoxal setae are placed on the median edge of coxae IV. One pair each of para-anal and anal st-setae present. Lyrifissures occur laterad to the para-anal setae. The dense ventral idiosomal striae are finely papillate.

Gnathosoma ( Figs. 2, 3 a & b) The components of the gnathosoma are rather strongly sclerotized.

Hypognathum ( Fig. 2 ) Ventral surface punctated; with two pairs of adoral on the entomalae and 4 pairs of hypognathal (hg1–4) setae. St-setae hg1, hg2 on the hypostomal region and hg3 and hg4 on the coxal region; hg2 and hg3 are the longest. The posteroventral region is festooned with internal apodemes.

Palp ( Figs. 3 a & b) is much stouter than that of the male. It extends with the distal half of the telofemur, genu and tibiotarsus past the entomalae. Its chaetotaxy is as follows: trochanter 0; basifemur 1 distodorsal sts; telofemur 1 apophysis about halfway its length, 1 distodorsal spine-like sts; genu 1 spine proximomedially, 2 spines distally, 1 apophysis; tibiotarsus 1 proximomedian sts, 1 ventral tubercle, 2 short sts, 1 tsl and the claw.

Chelicerae. Very closely resembles those of the male ( Fig. 12 ). They are long, slender and dorsally reticulate on the proximal third part of segment II. A cheliceral seta is present.

Legs ( Figs. 4-7 ). The dorsal surfaces of most leg segments are reticulate. The holotype has 3 stub-like solenidia on genu IV; this seems to be an individual variation/deviation from the usual 1 or 2 asl in females. Leg chaetotaxy: coxae I– IV 3 sts, 1 peg – 2 sts – 3 sts – 2 sts; trochanters I– IV 1 – 1 – 2 – 1 sts; basifemora I– IV 3 sts, 1 long spinelike seta – 4 sts, 1 long spine-like seta – 4 sts, 1 long spine-like seta – 1 sts, 1 long stout spine-like seta; telofemora I–IV 2 distodorsal spine-like setae, 2 sts – 3 sts, 1 distodorsal spine-like seta – 1 long thick ms, 1 spine-like seta, 2 sts – 1 long ms, 2 long spinelike seta; genua I – IV 3 asl, {1 bsl,1 sts}, 4 sts – 2 asl, 5 sts – 1 asl, 5 sts – 3 stub-like bsl, 4 stout sts, 1 sts; tibiae I – IV {1 sts, 1 bsl}, 1 asl, 4 sts – {1 sts, 1 bsl}, 4 sts – 1 short bsl, 5 sts – 1 T, 4 sts; tarsi I – IV 3 asl, {1 bsl, 1fmls, 1 sts}, 1 dtsl, 2 tsl, 18 sts (of which 4 are spines) – 1 bsl, 1 dtsl, 1 tsl, 21 sts (of which 3 are spines) – 1 tsl, 21 sts – 21 sts.

Male. ( Figs. 8–16 ). Dimensions. Idiosoma : length 247; width 173; length hypognathum 123; width hypognathum 65; length palp 154; length chelicera 116; length legs: I 285–289; II 250–273; III 277–284; IV 296–304; length sensillae vi 170–175, sce 206–216.

Idiosoma ( Figs. 8 a & 9). The idiosomal form is typical of most Armascirus males. The separate dorsal and ventral shields (including the coxal shields), although weakly sclerotised, are discernable. These idiosomal shields, excluding the genital shields, are provided with papillae forming an external reticulate pattern.

Dorsum ( Fig. 8 ). The dorsum ( Fig. 8 a) is provided with 11 pairs of setal structures. The finely setose sensillae vi and sce ( Figs 8 b & 8c) are unequal in length; the latter pair being the longer. Setae ve are closest to sce. Setae sci occur laterally to a faint median circular area. Hysterosomal setae c1, c2, d1, e1 and f1 occur on the shield; the latter pair being the longest of these setae. Setae f2 lacking. Setae h1 and h2 occur behind the shield on the integument; setae h1 are the longest dorsal setae. A pair of para-anal setae is present. A pair of lyrifissures occur laterally near setae f1. The dorsal integument is densely striated; the latter are very finely papillate.

Venter ( Fig. 9 ) The hysterosomal shield and coxal shields are fused: all being reticulate externally. This combined shield carries 15 pairs of sensory structures distributed as follows: coxa I area 3sts, 1 peg, coxa II–IV areas 1-3-2 sts and 6 hysterogastral setae, the pair of propodogastral setae and paracoxal seta pairs ( Fig. 9 ). The genital shields have 4 setae each, viz. g1–g4. The aedeagus is visible. Two pairs of genital papillae occur in the genital vestibule. Lyrifissures occur in the anal region.

Gnathosoma ( Figs. 10–12 ) The gnathosomal components are typical for the genus.

Palp ( Fig. 11 ). Chaetotaxy is similar to that of the female but sensory structures differ considerably. It has the following chaetotaxic features: trochanter, no setae; basifemur with a dorsal st-seta distally; telofemur with 1 dorsal spine-like seta and 1 short median apophysis distally; genu with 3 spine-like setae and 1 apophysis; tibiotarsus with 1 long proximal seta, a spine halfway along the segment, 2 small setae just distal to the spine, 1 terminal solenidion and a bifid terminal claw1. The palp extends from the distal half of the telofemur, genu and tibiotarsus past the entomalae.

Chelicerae ( Fig. 12 ) and hypognathum ( Fig. 10 ) resemble those of the female but are smaller in dimensions.

Legs ( Figs. 13–16 ). All leg segments are dorsally reticulate. Leg chaetotaxy: coxae I – IV 3 sts, 1 peg – 1 sts – 3 sts – 2 sts; trochanters I–IV 1 – 1 – 2 – 1 sts; basifemora I – IV 5 – 5 – 3 – 0 sts; telofemora I – IV 4 sts – 4 sts – 3 sts, 1 long sts – 3 sts, 1 long sts; genua I – IV {1 asl, 1 bsl, 1 sts}, 2 asl, 4 sts – 1 bsl, 1 asl, 5 sts – 1 asl, 5 sts – 2 asl, 5 sts; tibiae I – IV 1 bsl, {1asl, 1 sts}, 4 sts – {1 asl, 1sts} 4 sts – {1 bsl, 1 sts}, 4 sts – 1 T, 4 sts; tarsi I – IV 3 asl, {1bsl, 1fmls, 1sts}, 1dtsl, 2 tsl,16 sts – {1 bsl, 1 sts}, 1 dtsl, 1 tsl, 17 sts – 1 tsl, 17 sts – 17 sts.

1. The bifid condition of the palpal terminal claw in the Cunaxidae is an often observed feature. The senior author is of the opinion that this condition is not a species characteristic but should rather be regarded as individual variation in a population of a species. This is shown by the present description where the male palp shows the bifid condition which is lacking in the female.

Remarks. This species is closely related to Armascirus huyssteeni Den Heyer, 1978 . The new species differs from the latter species as indicated in Table 1 .

Figures

FIGURES 1 – 3. Armascirus braziliensis Den Heyer & Castro sp. nov. Female. Dorsum (1 a); venter (1 b): sensillum vi (1 c); sensillum sce (1 d); hypognathum (2); palp (3 a); proximal spine-like seta on palpal genu (3 b). Unmarked measuring bar (UMB) = 100 μm.

FIGURES 4 - 8 a. Armascirus braziliensis Den Heyer & Castro sp. nov. Female. Leg I (4); leg II (5); leg III (6); leg IV (7); Male. Dorsum (8 a). UMB = 100 μm.

FIGURES 8 b, c – 12. Armascirus braziliensis Den Heyer & Castro sp. nov. Male. Sensilla vi (8 b); sensillae sce (8 c); venter (9); hypognathum (10); palp (11); chelicera (12). UMB = 100 μm.

FIGURES 13 – 16. Armascirus braziliensis Den Heyer & Castro sp. nov. Male. Leg I (13); leg II (14); leg III (15); leg IV (16). UMB = 100 μm.