Trachygamasus karuni Farahi & Witaliński, 2019

Farahi, Sara, Shishehbor, Parviz, Nemati, Alireza & Witaliński, Wojciech, 2019, Trachygamasus karuni sp. nov., a new mite species from Iran (Parasitiformes: Parasitidae), Zootaxa 4706 (3), pp. 439-450 : 440-448

publication ID	https://doi.org/ 10.11646/zootaxa.4706.3.4
publication LSID	lsid:zoobank.org:pub:29429537-8240-4E24-B926-6F23A7BD151E
persistent identifier	https://treatment.plazi.org/id/03C71F47-FFD8-FF9E-DABC-C0F8FD4DFEF3
treatment provided by	Plazi
scientific name	Trachygamasus karuni Farahi & Witaliński
status	sp. nov.

Treatment

Trachygamasus karuni Farahi & Witaliński sp. nov.

( Figures 1–24 View FIGURE 1 View FIGURE 2 View FIGURES 3–5 View FIGURES 6–13 View FIGURE 14 View FIGURES 15–19 View FIGURES 20–24 )

urn:lsid:zoobank.org:act:396D61D8-4620-4E78-9701-CAA94B4614FD

Diagnosis (female and male). Cuticle well sclerotised with many regularly distributed pits; podonotum with 23 pairs of setae (all four sets of normal setae present except setae r1), setae j4, z5 and r3 thickened and terminally pilose, seta j1 only moderately; opisthonotum with 24 setae and 2–3 lateral setae unidentifiable on each side, setae Z1, Z4 thicker and apically pilose; opisthogastric setae JV4, JV5 and ZV4 enlarged and terminally pilose, in females setae JV5 and ZV4 located on soft cuticle; gnathotectum trispinate with central prong broader and more solid than the lateral ones which are thin and acute, sometimes curved; gv1 gland pores not discernible; sternal poroid iv3 circular, pore iv5 followed laterally by three-opening gv2 gland.

Female: epigynium bell-shaped with convex lateral margins and concave posterior margin; endogynium hyaline and poorly visible as axially elongated saccule.

Male: presternal platelets large; genital lamina with bar-shaped anterior thickening and a hyaline protrusion directed anteriad; sternal setae st1 far from the anterior sternal margin; leg II with minute spurs: one on the femur and one on the genu, whereas none on the tibia.

Description. Female ( Figures 1–4 View FIGURE 1 View FIGURE 2 View FIGURES 3–5 , 6–13 View FIGURES 6–13 )

Dorsal idiosoma ( Figure 1A View FIGURE 1 ). Idiosoma well sclerotised, brownish and pyriform in outline, 485–560 long, 325–450 wide (n=6), holotype 560 long, 405 wide. Podonotum and opisthonotum separated by lines in cuticle behind podonotal setae. Cuticle with many regularly distributed pits. Dorsal setae simple, except j1, j4, r3, z5, Z1 and Z4 larger and terminally pilose ( Figure 1B View FIGURE 1 ), seta j1 only moderately. Length of simple dorsal setae: 14–20, larger setae length: 22–27 (j1), 29–33 (j4), 42–47 (r3), 30–33 (z5), 31–34 (Z1), 29–37 (Z4). Length of peritrematal groove 258–275 (holotype 275); expanded behind coxa I, ending near podonotal seta z1 and poroid idj1 ( Figures 2 View FIGURE 2 and 3 View FIGURES 3–5 ).

Ventral idiosoma ( Figure 2 View FIGURE 2 ). Presternal plates ( Figures 2 View FIGURE 2 and 6 View FIGURES 6–13 ) distinct, with anterior and lateral margins thickened. Tritosternum present, biramous. Sternal shield with moderately visible reticulation in the anterior part and two pairs of circular depressions posteriorly to the sternal poroids iv2, and behind st4 setae ( Figures 2 View FIGURE 2 and 7 View FIGURES 6–13 ). Idiosoma margin behind anus convex.

Genital region ( Figures 2 View FIGURE 2 and 7 View FIGURES 6–13 ). Paragynia fused with the sternal shield. Poroids iv3 roundish, gv1 absent. Epigynal shield bell-shaped, with convex lateral margins and concave posterior margin; three pairs of thickenings, located in the central part of epigynium, are discernible ( Figure 7 View FIGURES 6–13 ). Endogynium ( Figures 2 View FIGURE 2 , 7 and 8 View FIGURES 6–13 ) hyaline, weakly visible as an axially oriented saccular structure, with thin arcuate lines located laterally. Poroids iv5 situated at some distance behind the posterior epigynal margin, gv2 gland with three openings.

Setation of ventral idiosoma. Setae of sternogenital region — holotype: 20 (st1), 17 (st2), 18 (st3), 20 (st4), 21 (st5); paratypes: 18–25 (st1), 17–25 (st2), 16–20 (st3), 13–16 (st4), 16–18 (st5). Opisthogaster setae — holotype: 26 (JV1), 36 (JV2), 34 (JV3), 41 (JV4), 13 (ZV1), 37 (ZV2 and ZV3), 16 (Ad); paratypes: 21–25 (JV1), 27–35 (JV2), 29–35 (JV3), 32–38 (JV4), 10–14 (ZV1), 27–33 (ZV2), 26–34 (ZV3), 16–20 (Ad). Sternal and opisthogastric setae simple except JV4 enlarged and terminally pilose. Setae JV5 and ZV4 located on soft cuticle and similar to JV4.

Gnathosoma ( Figures 4 View FIGURES 3–5 , 9, 10 View FIGURES 6–13 ). Gnathotectum trispinate ( Figure 9 View FIGURES 6–13 ), central prong with rounded apex, lateral prongs narrow and sharply pointed. Corniculi conical and short. Hypostome ( Figure 4 View FIGURES 3–5 ): hypognathal groove with 4–7 rows of denticles, hypostomatic and palpcoxal setae simple, internal posterior hypostomatic setae longer, i.e. ca. twice the length of the external posterior setae. Chelicera ( Figure 10 View FIGURES 6–13 ): fixed digit with one tooth in the front and three teeth behind pilus dentilis, the posterior tooth divided into two parts, anterior and posterior. Movable digit with three teeth, the proximal one largest. Palp trochanter with seta v1 and v2 simple. Setae al on palp femur and genu spatulate.

Legs. Coxa I with a thickening indented at the level between setae v1 and v2 ( Figure 11 View FIGURES 6–13 ). Ambulacra of legs II–IV characteristic, i.e. anterior pulvilli irregular in shape, but terminally rounded, lateral pulvilli narrow, curved and acuminate ( Figure 12 View FIGURES 6–13 ). Leg chaetotaxy normal, all setae smooth and needle-like except for posterolateral and some posterodorsal setae on genu and tibia I, femur II, genu II and tibia II, as well as genu IV and tibia IV which are narrow, but terminally blunt ( Figure 13 View FIGURES 6–13 ). Other aspects of the leg structure and setation unremarkable.

Male ( Figures 5 View FIGURES 3–5 , 14–24 View FIGURE 14 View FIGURES 15–19 View FIGURES 20–24 )

Dorsal idiosoma ( Figure 14 View FIGURE 14 ). Paratypes with holodorsal shield showing poorly discernible border between podonotum and opisthonotum. Idiosoma oval, well sclerotised and brown, 460–485 long, 260–315 wide, n=5. Dorsal setation as in female: podonotal setae simple except for j1, j4, r3 and z5. The length of simple podonotal setae 12–18, j 1 18–24, j 4 29–33, r3 39–42, z5 33. Opisthonotal setae as in the female. The length of simple opisthonotal setae is 13–16, Z 1 30–33, Z 4 21–26. Peritrematal groove 248–258 long, expanding to beyond coxa I. Cuticle shows many regularly distributed pits.

Ventral idiosoma ( Figure 15 View FIGURES 15–19 ). Tritosternum absent, presternal plates large ( Figures 15 and 16 View FIGURES 15–19 ). Sternogenital shield anterior margin ( Figures 15 and 16 View FIGURES 15–19 ) with a concavity behind the genital lamina. Genital lamina shows a short posterior part covered with sternum; in its anterior part there are two lateral thickenings and a bar-shaped anterior thickening. Poorly visible, anteriorly protruded, apically barbed hyaline extension is present ( Figure 16 View FIGURES 15–19 ). Sternal setae simple and similar, their length: 17–21 (st1–st3), 16–17 (st4), 12–13 (st5); opisthogastric setae simple except for JV4, as well as JV5 and ZV4 which are larger and terminally pilose and located marginally, or setae JV5 even somewhat dorsally. Their length: 20–21 (JV1), 25–27 (JV2 and JV3), 29–33 (JV4, JV5, ZV4), 9–10 (ZV1), 24–27 (ZV2, ZV3), 12–14 (Ad). Sternal poroids iv3 circular. Idiosomal margin behind the anus is convex.

Gnathosoma ( Figure 5 View FIGURES 3–5 , 17–19 View FIGURES 15–19 ). Gnathotectum trispinate ( Figure 18 View FIGURES 15–19 ), central prong larger than the lateral prongs and rounded terminally, ending with an additional pointed apex. Lateral prongs acuminate as in female. Corniculi ( Figures 5 View FIGURES 3–5 and 17 View FIGURES 15–19 ) short and conical; hypognathal groove with 5–6 posterior rows of denticles ( Figure 5 View FIGURES 3–5 ). Hypostomatic and palpcoxal setae simple; internal posterior hypostomatics more than double length of external ones. Chelicera ( Figure 19 View FIGURES 15–19 ): fixed digit with two minute denticles in front of pilus dentilis and dentate lamellar ridge behind pilus dentilis. Movable digit with one tooth followed by a sinuous ridge. Palp trochanter ( Figure 17 View FIGURES 15–19 ) with a thickened ridge anteroventrally; seta v1 and v2 simple. Anterolateral setae on the palp femur and genu spatulate.

Legs. Characteristic ambulacra of legs II–IV as in the female. Leg II ( Figures 20–24 View FIGURES 20–24 ) spurred as follows: the femur with one minute spur ventrally, genual spur located anteroventrally. Both spurs minute and conical. Posterolateral seta pl1 on the femur, posterolateral setae pl1 and pl2 on the genu and tibia, as well as posterodorsal setae pd1 on the genu and the tibia thickened and terminally pilose. The other setae on leg II simple. Some anterodorsal setae on femur IV and genu IV terminally blunt. Other aspects of the legs unremarkable.

Etymology. The specific name karuni refers to the Karun, Iran’s only navigable river, running along the sam- pling areas for the new species.

Remarks. As shown in the key to Trachygamasus species, the newly described species is morphologically similar to T. borealis Ma & Wang, 1996 , T. gerdi Witaliński, 2017 and T. pseudogerdi Yao, Jin & Zhang, 2019 . Trachygamasus karuni can be easily distinguished from these species due to the characteristic sternal (paragynal) poroids iv3, which are roundish rather than elongate, as well as the shape of the saccular endogynium in the female. The males of the newly described species are distinguishable due to leg II spurs, one on femur II and one on genu II, but not on tibia II. To date, T. karuni sp. nov. is the only Trachygamasus this type of spur arrangement on leg II.

The new species is the fifth species of Trachygamasus showing spurs on leg II in the male. The others are T. borealis Ma & Wang , T. medianus Tichomirov , T. gerdi Witaliński, 2017 and T. pseudogerdi Yao, Jin & Zhang, 2019 . It should be emphasised that the spurs in Trachygamasus males are minute, even if present, and thus may have been overlooked, especially in earlier descriptions. It is the fourth species with a characteristic, hyaline uniramous anterior protrusion of the male genital lamina.