Riscus austroamericanus Den Heyer
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publication ID |
https://doi.org/ 10.5281/zenodo.280740 |
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DOI |
https://doi.org/10.5281/zenodo.6177424 |
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persistent identifier |
https://treatment.plazi.org/id/03D19D51-FF8F-FFA9-6BD1-FBEDFD8CF84F |
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treatment provided by |
Plazi |
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scientific name |
Riscus austroamericanus Den Heyer |
| status |
sp. nov. |
Riscus austroamericanus Den Heyer sp. nov.
Material examined: 1 female holotype, Coffea arabica L., Quillabamba, Cuzco, Peru (12° 5' 19.6” S / 72°42' 13.3” W), A.D.G. Alvarado, 04-VII-2006; 1 paratype tritonymph, Solanum nigrum L., Quillabamba, Cuzco, Peru (12° 5' 19.6” S / 72° 42' 13.3” W), A.D.G. Alvarado, 4-VII-2006; 1 paratype female, Coffea arabica L., Quillabamba, Cuzco, Peru (12° 5' 19.6” S / 72°42' 13.3” W), A.D.G. Alvarado, 04-VII-2007; 1 paratype female, Euterpe sp., Recife, Pernambuco, Brazil (8° 02' S / 40° 01' W), Gondim Jr, M. G. C., 5-I-1999, slide MZLQ 3050; 1 paratype female, 1 paratype deutonymph, Pisidium guajava Ilhéus , Bahia, Brazil (13° 01'S / 40° 01'W), 31-VII-2007, A.R. Oliveira.
Description.
Female ( Figs. 39–48 View FIGURES 39 – 40 b View FIGURE 41 View FIGURES 42 – 48 ) Dimensions. Idiosoma : length 394 (335–443); width 287 (246–300); length hypognathum 128 (108–135); width hypognathum 80 (77–85); length palp 108 (96–117); length chelicera 114 (94–137); length legs I 241 (219–270); II 246 (223 -285); III 287 (235–304); IV 308 (289–320); length sensillae vi 125 (116–135) and sce 155 (139–158).
Dorsum ( Fig. 39 View FIGURES 39 – 40 b a,b & 41 a–c). The demarcation of the propodosomal shield is very vague ( Fig. 39 View FIGURES 39 – 40 b a & b). The same is true for the integumental striae. Only one very finely reticulate propodosomal shieldlike area ( Fig. 41 View FIGURE 41 a) on the idiosoma : it bears setal pairs ve and sci as well as sensilla pairs vi and sce ( Figs 41 View FIGURE 41 b&c, respectively); the latter are the longest sensillae. Except for setae sci all dorsal setae are rather short. Setae h1 are the longest hysterosomal setae.
Venter ( Fig. 40 View FIGURES 39 – 40 b a, b). As with the dorsum hysterogastral “shields” and striae are poorly defined. Setae pcs (= paracoxal seta) occur on the median margin of coxae IV. Three pairs of hysterogastral setae. The genital area ( Fig. 42 View FIGURES 42 – 48 ) is recognised by the 5 pairs of g-setae. A pair of paragenital setae occur laterally to the anterior half of the genital region. The chelicera possesses a near terminal seta. The length ratio width:length of the hypognathum is 1: 1.5
Hypognathum ( Fig. 43 View FIGURES 42 – 48 ). The coxal region is finely papillate whereas the hypostome is longitudinally striate. Setae hg1 are short and immediately posteriad the entomalae with its 4 small adoral setae; setae hg2–4 are long; setae hg4 are situated medially to setae hg3 forming a nearly straight transverse row ( Fig. 43 View FIGURES 42 – 48 ).
Palp ( Fig. 44 View FIGURES 42 – 48 ) reaches past the entomalae with nearly the entire length of its tibiotarsusus. Its chaetotaxy is as follows: trochanter, 0; basifemur, 1 sts shorter than the segment; telofemur, 1 dorsal sts; genu, 2 sts, 1 strong, curved sts proximally and 1 straight spine-like sts; tibiotarsus, 1 ventral sts, 1 very strong median tubercle, 2 sts, 1 tsl, 1 claw. The palpal segments are finely papillate.
Legs ( Figs. 45–48 View FIGURES 42 – 48 ). Leg chaetotaxy: coxae I – IV 3 sts, 1 peg – 1 sts – 3 sts – 1 sts; trochanters I – IV 1 – 1 – 2 – 1 sts; basifemora I – IV 3 – 3 – 2 – 1 sts; telofemora I – IV 4 – 4 – 4 – 4 sts; genua I – IV {2 asl}, {1 asl, 1 sts}, 1 longish asl, 4 sts – 2 asl, 5 sts – 1 asl, 5 sts – 1 asl, 5 sts; tibiae I – IV {2 asl, 1 sts}( Fig 45 View FIGURES 42 – 48 b), 4 sts – 1 asl, 5 sts – 1 bsl, 5 sts – 1 T, 3 sts; tarsi I – IV 3 asl, {1 asl, 1 sts, 1 fmls}, 1 dtsl, 2 tsl, 15 or 16 sts – 1 bsl, 1 dtsl, 1 tsl, 16 or 17 sts – 1 tsl, 14 or 15 sts – 15 or 16 sts.
Remarks. Differences between the two known species of Riscus shown in Table 4 View TABLE 4 .
*All kinds (= bsl, asl); **micrometers
TABLE 4. Major differences between the known species of Riscus.
| Features/species | R. thailandensis | R. austroamericanus |
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| Genu II | 2 asl, 5 sts | 2 asl, 4 sts |
| Tibia I | {1 long bsl, 1 asl, 1 sts},4 sts | {2 asl}, 4 sts |
| Tibia II | {1 asl, 1sts},4 sts | 1 asl, 4 sts |
| Tibia IV | 1 T, 4 sts | 1 T, 3 sts |
| Tarsus I | 3 asl,{1 bsl, 1 sts,1 fmls}, 1 dtsl, 2 tsl, 13 sts | 3 asl, {1 asl, 1 sts,1fmls}, 1 dtsl, 2 tsl, 15 or 16 sts |
| Genital setae | 8 sts | 10 sts |
| Number Solenidia*: Genua I-IV | 5 – 2 – 1 - 1 | 4 – 2 – 1 - 1 |
| Body length** (excl gnathosoma ) | 219 (211–226) | 394 (335–443) |
| Body width | 141 (139–142) | 278 (246–300) |
| Length hypognathum | 83 (82–85) | 128 (108–135) |
| Seta palp basifemur | Longer than basifemur | Shorter than basifemur |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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