Helicotylenchus pseudorobustus (Steiner, 1914) Golden, 1956

Shokoohi, Ebrahim, Marais, Mariette, Fourie, Hendrika & Panahi, Hadi, 2018, Morphological and molecular characterization of three Helicotylenchus species from Iran, Zootaxa 4388 (2), pp. 207-220 : 210-211

Helicotylenchus pseudorobustus (Steiner, 1914) Golden, 1956

( FiguRE 2 )

Helicotylenchus pseudorobustus WaS dEScRibEd fROm SOil cOllEcTEd fROm undER mOSS nEaR AlTmaTT, SWiTzERland and SubSEquEnTlY REpORTEd fROm all ThE biOgEOgRaphical REgiOnS. FORTunER et al. (1984) REpORTEd ThaT H. pseudorobustus iS cOnSidEREd afTER H. dihystera and H. multicinctus , TO bE ThE mOST fREquEnTlY REpORTEd SpEciES Of ThE gEnuS WORldWidE. RaThORE & TiWaRi (2016) REpORTEd 47 planT SpEciES ThaT acT aS hOSTS Of H. pseudorobustus .

Measurements. SEE TablE 1.

Description. FEmalES (n = 12): HabiTuS SpiRal. Lip REgiOn 4.1 ± 0.3 (3.83–4.9) µm high and 5.8 ± 0.8 (4.9– 7.73) µm WidE, anTERiORlY hEmiSphERical and cOnTinuES WiTh bOdY cOnTOuR, WiTh ThREE TO fOuR annulES. ThE labial fRamEWORk iS SclEROTizEd, OuTER maRginS EXTEnd 1–2 µm backWaRd fROm baSal plaTE. CEphalidS nOT SEEn. STYlET 25.2 ± 1.9 (23.5–27) µm lOng, cOnuS 10.6 ± 0.6 (9.8–12) µm. STYlET knObS 2.3 ± 0.38 (2.0–3.2) µm high and 5.7 ± 1.34 (4.9–9.8) µm WidE, anTERiOR facES flaTTEnEd (85%) TO indEnTEd (15%). POSiTiOn Of DGO 8.2 ± 1.17 (6.8–9.8) µm pOSTERiOR TO STYlET knObS. MEdian phaRYngEal bulb OVal TO ROundEd, 1 3–14 µm lOng and 9–10 µm WidE; ValVE 3–4 µm lOng and 2–3 µm WidE. HEmizOnid OnE TO TWO annluES lOng, lOcaTEd OnE TO TWO annulES anTERiOR TO SEcRETORY- EXcRETORY pORE. HEmizOniOn nOT SEEn. NERVE Ring aT iSThmuS lEVEl, aT 95.8 ± 6.9 (85–106) µm fROm anTERiOR End Of nEmaTOdES and 12.3 ± 1.6 (9.6–15.9) % Of ThE bOdY lEngTh. SEcRETORY-EXcRETORY pORE OpEning OppOSiTE iSThmuS lEVEl aT 116.3 ± 4.4 (1106–126) µm fROm anTERiOR End Of nEmaTOdES, 14.9 ± 1.12 (12.3–16.8) % Of ThE bOdY lEngTh. DEiRidS nOT ObSERVEd. TWO bRanchES Of REpROducTiVE TRacT bOTh funcTiOnal, lEngTh Of pOSTERiOR bRanch 82.4 ± 22.9 (57.8–134) % Of cORRESpOnding anTERiOR bRanch lEngTh; anTERiOR bRanch 170.5 TO 293. µm and pOSTERiOR bRanch 124 TO 275 µm lOng; EpipTYgma ROundEd, SpERmaThEca aXial; VulVa SiTuaTEd aT 46 TO 65 % Of bOdY lEngTh. LaTERal fiEld 5.3 ± 1.14 (3.9–6.8) WidE; innER TWO linES End On Tail in a U-ShapEd paTTERn. REcTum 0.9–1.2 TimES ThE anal bOdY diamETER. InTESTinE nOT EXTEndEd OVER REcTum. Caudalid nOT SEEn. PhaSmid lOcaTEd fROm EighT TO 13 annulES anTERiOR TO anuS, WiTh a diamETER Of 0.5–0.7 µm bETWEEn SEcOnd and ThiRd linE. Tail 20 ± 2.9 (14–25) µm lOng, WiTh SEVEn TO 11 VEnTRal annulES, Tail mORE cuRVEd dORSallY WiTh ROundEd pROJEcTiOn (3–4 µm lOng).

MalE: nOT fOund.

Locality and habitat. SpEcimEnS cOllEcTEd fROm ThE RhizOSphERE Of a Poa Sp. , in KERman (KERman PROVincE), SOuThERn IRan.

Other material examined (SEE TablE 1). ThE OThER pOpulaTiOn EXaminEd iS VERY SimilaR TO ThE pOpulaTiOn fROm KERman.

Remarks. ThE SpEcimEnS WERE cOnSidEREd TO bE H. pseudorobustus bEcauSE Of SpiRal habiTuS, ROundEd lip REgiOn, bOdY lEngTh (mEan 711–782 µm), pOSiTiOn Of VulVa (mEan 59–62%), phaSmidS anTERiOR TO anuS, Tail mORE cuRVEd dORSallY WiTh ROundEd pROJEcTiOn and malES abSEnT. ThE pRESEnT SpEcimEnS Of H. pseudorobustus cOnfORmEd TO ThE amEndEd dEScRipTiOn Of FORTunER et al. (1984) and SubbOTin et al. (2015). ThE cuRREnT SpEcimEnS’ dEScRipTiOnS agREEd WiTh ThE IRanian SpEcimEnS REpORTEd bY MOhammad DEimi and MiTkOWSki (2010), hOWEVER, ThEY diffER in Tail lEngTh (13.7–24.5 vs 7.1–11.3 µm). GEnERallY, ThE uppER RangE Of ThE bOdY lEngTh (934 µm) WaS lOngER Than ThE pREViOuSlY REcORdEd 895 µm (SubbOTin et al. 2015).

DNA chaRacTERiSaTiOn: ThE 28S RRNA gEnE SEquEncES Of H. pseudorobustus amplifiEd bY ThE TWO pRimERS D2A and D3B WERE 409 and 486 baSE paiRS (bp) lOng, RESpEcTiVElY. WiThin ThiS fRagmEnT, 16 bp diffEREncES diSTinguiShEd ThE IRanian pOpulaTiOn ( MF996708 ) fROm ThE ITalian pOpulaTiOn Of H. pseudorobustus (accESSiOn nR. DQ328750 ; 96% idEnTiTY) and 19 bp fROm ThE USA H. dihystera SpEcimEnS (accESSiOn nR. HM014262 ; 97% idEnTiTY). In addiTiOn, ThE OThER pOpulaTiOn STudiEd ( MF996709 ) ShOWEd 99% SimilaRiTY and SEVEn bp diffEREncES WiTh ThE ITalian pOpulaTiOn Of H. pseudorobustus ( DQ328750 ).

Figures

FIGURE 2. Helicotylenchus pseudorobustus (STEINER, 1914) GOLDEN,1956. A: NECK.B,C: ANTERIOR END (STOMA AND DGO).D: FEMALE REPRODUCTIVE SYSTEM.E: ENTIRE FEMALE.F, G: FEMALE POSTERIOR END.