Anim. Syst. Evol. Divers. Vol. 35, No. 2: 41-48, April 2019 https://doi.org/10.5635/ASED.2019.35.2.029 Review article First Record of Two Pseudacrobeles Species (Nematoda: Rhabditida: Cephalobidae) in South Korea Taeho Kim, Joong-Ki Park* Division of EcoScience, Ewha Womans University, Seoul 03760, Korea ABSTRACT Pseudacrobeles (Pseudacrobeles) variabilis (Steiner, 1936) Steiner, 1938 and P. (Bunobus) pseudolatus (Hernández, 1990) De Ley, Siddiqi and Boström, 1993 belonging to the family Cephalobidae Filipjev, 1934 are newly reported from South Korea. Pseudacrobeles (Pseudacrobeles) variabilis is distinguished from its congeners by having distinctly setiform cephalic probolae, three rounded or knob-shaped labial probolae and longer female tail. Pseudacrobeles (Bunobus) pseudolatus is distinguished from its congeners by having visibly lateral lips, a short post-uterine sac, elongated conoid tail in the female, and acute mucro on the tails of both sexes. In this study, details of the morphological characters and morphometrics of Korean populations of P. (P.) variabilis and P. (B.) pseudolatus are described and illustrated based on optical microscopy. Keywords: Cephalobidae, Pseudacrobeles, Bunobus, new record, South Korea INTRODUCTION and Africa (Schuurmans-Stekhoven, 1951; Loof, 1964; De Ley et al., 1993a, 1993b). To date, only one Pseudacrobeles The genus Pseudacrobeles was established by Steiner in species, P. (P.) curvatus, has been reported in South Korea 1938. During a taxonomic revision of the genus, De Ley et (Kim et al., 2017). al. (1993a, 1993b) classified it into the subgenera Pseudac­ During a survey of several plots of farmland, P. (P.) vari­ robeles Steiner, 1938 and Bunobus De Ley, Siddiqi and Bo- abilis (Steiner, 1936) Steiner, 1938 and P. (B.) pseudolatus ström, 1993 based on morphological characters of the lip re- (Hernández, 1990) De Ley, Siddiqi and Boström, 1993 were gion. Pseudacrobeles species have triradiate lips (very rarely collected and isolated from soil samples from pear and po- with hexaradiate or bilateral symmetry) and labial probo- tato farms. In this paper, we provide detailed descriptions of lae (if absent the lips are low and amalgamated), whereas the morphological characters and morphometrics of P. (P.) Bunobus species have bilaterally symmetric lips, no labial variabilis and P. (B.) pseudolatus from South Korea. or cephalic probolae, and smaller lateral lips than subdorsal and subventral lips. Although Andrássy (2005) elevated the subgenus Bunobus to genus level separate from the subge- MATERIALS AND METHODS nus Pseudacrobeles, we here treat each as a subgenus until further confirmation. Nematode isolation Pseudacrobeles species are found on every continent in the Soil samples were collected from soil below pear trees world except Antarctica. Records exist for South Ameri- (Gongdo-eup, Anseong-si, Gyeonggi-do, South Korea [co- ca (Loof, 1964; Andrássy, 1968; Zell, 1987; De Ley et al., ordinates: 37°01ʹ01.1ʺN, 127°10ʹ23.4ʺE]) and potato farm 1993a, 1993b), Europe (Zell, 1987; Hernández, 1990; Holo- soil (Buk-myeon, Uichang-gu, Changwon-si, Gyeongsang- vachov and De Ley, 2001; Abolafia et al., 2002; Abolafia and nam-do, South Korea [coordinates: 35°22ʹ22.5ʺN, 128° Peña-Santiago, 2005; Holovachov and Boström, 2006; Ab- 36ʹ47.3ʺE]). Nematode specimens were extracted by sieving olafia and Peña-Santiago, 2013), Asia (De Ley et al., 1993a, and the Baermann funnel method (Baermann, 1917). 1993b; Shokoohi and Abolafia, 2012; Kim et al., 2017), This is an Open Access article distributed under the terms of the Creative *To whom correspondence should be addressed Commons Attribution Non-Commercial License (http://creativecommons.org/ Tel: 82-2-3277-5948, Fax: 82-2-3277-2385 licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, E-mail: [email protected] and reproduction in any medium, provided the original work is properly cited. eISSN 2234-8190 Copyright The Korean Society of Systematic Zoology Taeho Kim, Joong-Ki Park Fixation and morphological observations occupying 18.7-21.2% of width of body at mid-body; inci- Each nematode specimen was transferred to 2 mL of water sures fading out at phasmid region. Head region continuous in a 15 mL tube, to which was quickly added 4 mL of 80°C with neck. Lip region 7.3-7.6 μm in diameter, with triradiate TAF (2% triethanolamine and 7% formaldehyde) for fix- symmetry, six cephalic probolae distinctly setiform, three ation. The fixed nematodes were processed to dehydrated labial probolae rounded or knob-shaped, with six labial and glycerin as described by Seinhorst (1959) and mounted in four cephalic papillae. Stoma cephaloboid, length 1.7-1.9 pure glycerin on HS slides (Shirayama et al., 1993). Nema- times the lip region diameter. Cheilorhabdions bar-shaped. tode morphological characters were observed under an opti- Pharyngeal corpus cylindrical, 3.4-4.0 times the isthmus cal microscope (BX-51; Olympus, Tokyo, Japan) equipped length. Isthmus narrower than corpus, distinctly demarcated with differential interference contrast. Morphometric char- from metacorpus. Basal bulb spheroid, with well developed acters were measured using a CoolSnap Photometrics color valves; 1.2-1.3 times as long as its width. Cardia conoid, CCD digital camera (MP5.0-RTV-R-CLR-10; Photometrics, surrounded by intestinal tissue. Nerve ring located at pos- Tucson, AZ, USA) and the program QCapture Pro 5 (QIm- terior corpus, at 61.0-63.2% of pharynx length. Excretory aging, Surrey, Canada). pore positioned at corpus-isthmus junction or anterior isth- mus, at 67.5-71.7% of pharynx length. Position of deirids in lateral field at isthmus level, at 77.3-80.9% of total neck SYSTEMATIC ACCOUNTS length. Female: Reproductive system monodelphic-prodelphic. Va- Order Rhabditida Chitwood, 1993 gina 0.3 body-diameters long. Post-uterine sac length 0.7- Suborder Tylenchina Thorne, 1949 0.9 times the body width. Uterus 2.3-2.4 body-diameters Infraorder Cephalobomorpha De Ley and Blaxter, 2002 long. Spermatheca length same as the body width. Oviduct Family Cephalobidae Filipjev, 1934 short. Ovary directed posteriorly, with double flexure. Rec- 1*Genus Pseudacrobeles Steiner, 1938 tum length 1.3-1.4 times the anal body diameter. Tail elon- 2*Subgenus Pseudacrobeles Steiner, 1938 gated conoid. Mucro 8.7-9.2 μm long, with a ragged sur- face. Phasmids at 25.1-25.7% of tail length. 3* Pseudacrobeles (Pseudacrobeles) variabilis Male: Genital system monorchic. Testis reflexed ventrad (Steiner, 1936) Steiner, 1938 (Table 1, Fig. 1) anteriorly. Spicules curved ventrad, 23.3-24.2 μm long; ma- Acrobeles variabilis Steiner, 1936: 76, fig. 23. nubrium rounded; calamus as wide as manubrium; without Pseudacrobeles variabilis Steiner, 1938: 37, fig. 13c-e. hump and velum; with one longitudinal incisure. Gubernac- Pseudacrobeles (Pseudacrobeles) variabilis De Ley et al., ulum slightly curved ventrad. Two pairs of pre-cloacal and 1993a: 223, figs. 1, 2, 3b-f, 3h-l; Abolafia et al., 2002: one pair of ad-cloacal subventral papillae present. Post-clo- 148, fig. 6. acal genital papillae in five pairs: one subventral and one lateral at mid-tail, one subdorsal near phasmid, two ventral Material examined. 2♀♀ and 2♂♂, South Korea: Gyeo- at tail terminus region. Tail conoid, bluntly terminus, with nggi-do, Anseong-si, Gongdo-eup, Deokbongseowon-ro, 04 bar-shaped mucro. Phasmid opening at 55.7-62.1% of tail Oct, 2017, extracted by sieving and the Baermann funnel length. method from soil below pear trees. Two specimens (slide Nos. Distribution. Brazil, Kenya, South Korea, Spain, Tanzania, NIBRIV0000754015 [female] and NIBRIV0000754016 USA. [male]) are deposited at the National Institute of Biologi- Habitat. Soil sample from a pear farm. cal Resources, Republic of Korea and two specimens (slide Remarks. Morphological characters and measurements of Nos. 01010403001 [female] and 01010403004 [male]) are the specimens described here perfectly fit the description deposited in the Animal Phylogenomics Laboratory, Ewha of P. (P.) variabilis in previous studies, except for the fe- Womans University, Republic of Korea. male tail mucro (long and ragged vs. with or without acute Measurements. See Table 1. mucro) (Steiner, 1936; De Ley et al., 1993a; Abolafia et Description. Adult: Body cylindrical; length 633.5-699.9 al., 2002). Intraspecific variation in some morphologies μm in females and 598.9-612.1 μm in males; ventrally (such as body size, tail length, and mucro shape) among curved after fixation, C-shaped in females, J-shaped in populations of this species has been reported from many males. Cuticle annulated; annuli 1.3-1.8 μm wide and 1.2- geographic areas: North America, Africa and Europe (Stein- 1.9 μm thick at mid-body. Lateral field with three incisures, er, 1936; De Ley et al., 1993a; Abolafia et al., 2002). Al- Korean name: 1*평두선충속 (신칭), 2*평두선충아속 (신칭), 3*다형평두선충 (신칭) 42 Anim. Syst. Evol. Divers. 35(2), 41-48 Two Species of Pseudacrobeles in South Korea ) ) )) ) 4 2 ) ) )85 6 eudolatus , n2♂ -±22.9(576.0608.= -±82.2(21.224.3) -±70.3(3.43.9) -±92.3(9.312.6) -±00.5(2.63.4)- -±52.3(40.944.1) -±23.5(23.728.7) -±36.9(157.4167. -±14.1(45.965.8) -±51.4(17.5619.5 -±01.4(3032) -±60.5(6.26.9) -±30.3(12.112.5) -±40.4(4.14.7) -±90.1(1.81.9) -±80.2(2.62.9) -±65.3(92.9100.4 -±82.0(30.433.2) -±82.3(16.119.4) -±51.4(13.515.5) -±20.0(1.21.3) -±00.0(3.03.1) -±53.8(96.9102.2 -±03.9(102.3107. -±93.8(114.2119. -±44.9(58.064.9) -±85.2(61.268.5) -±15.4(68.375.9)--- -±23.4(235.5268.----------- us) ps 592.222.3.10.3. 42.26.162.55.818.31.6.12.4.1.2.96.31.17.14.1.3.99.105.116.61.64.72. 252.1 b o n u B ( Pseudacrobeles , n2♀ -±633.283.3(574.3692.2)= -±20.61.9(19.321.9) -±3.90.3(3.64.1) -±11.50.4(11.211.8) -±3.00.0(3.03.0) -±63.21.3(62.364.1) -±30.12.3(28.531.7) -±31.16.9(26.235.9) -±163.38.0(157.6169.0) -±54.85.3(51.158.5) -±18.41.8(17.119.7) -±30.50.7(3031) -±6.90.2(6.87.1) -±13.21.4(12.114.2) -±5.00.4(4.75.3) -±1.90.3(1.72.1) -±2.70.5(2.33.0) -±93.36.9(88.498.2) -±30.60.1(30.630.7) -±19.71.0(18.920.4) -±15.72.3(14.017.3) -±1.30.1(1.21.3) -±3.00.2(2.93.2) -±107.412.6(98.5116.3) -±108.37.8(102.9113.8) -±123.84.3(120.8126.9) -±65.74.5(62.568.9) -±66.31.5(65.267.4) -±75.81.1(75.176.6) -±399.644.6(368.1431.2) -±173.933.7(150.1197.7) -±3.20.3(2.93.4) -±191.639.7(163.5219.7) -±9.91.8(8.711.2) -±23.41.2(22.524.2) -±52.016.7(40.263.9) -±37.211.2(29.345.1) -±19.70.1(19.619.7) -±154.628.3(134.6174.6) -±0.30.0(0.30.3) -±0.80.1(0.70.9) -±1.70.2(1.51.8) -±1.30.6(0.81.7) -±0.60.1(0.50.8) s u at ol d ) ) )) ) u 1 8 )50 8 dacrobeles(Bunobus) pse acrobeles) variabilis , n2♂ -±605.59.3(598.9612.= -±22.40.5(22.022.7) -±3.80.0(3.83.8) -±15.60.7(15.216.1) -±2.00.0(1.92.0)- -±58.01.7(56.959.2) -±27.10.2(26.927.2) -±159.01.1(158.3159. -±38.71.1(38.039.5) -±19.80.3(19.520.0) -±27.01.4(26.028.0) -±7.30.0(7.37.3) -±12.40.0(12.412.4) -4.7 0.1(4.64.8) -±1.70.0(1.71.7) -±2.60.1(2.62.7) -±95.50.6(95.195.9) -±26.62.0(25.228.0) -±19.40.6(18.919.8) -±15.50.2(15.415.7) -±1.20.1(1.21.3) -±3.60.3(3.43.8) -±100.40.8(99.9101.0 -±113.50.0(113.5113. -±126.81.6(125.7128. -±63.10.1(63.163.2) -±71.40.5(71.071.7) -±79.81.6(78.780.9)--- -±351.44.8(348.0354.----------- u d e u s e P s s) variabilis and (Pseudacrobeles n2 -(633.5699.9)=-19.321.6)-3.74.1)-7.27.2)-5.25.4)-60.761.1)-34.539.1)-29.336.2)-170.4172.2)-87.697.4)-16.318.6)-55.056.0)-7.57.6)-12.714.1)-4.35.3)-1.71.9)-2.62.9)-102.5103.2)-25.628.7)-20.921.9)-17.617.6)-1.21.2)-3.64.0)-105.1106.6)-115.0119.4)-131.6138.6)-61.062.5)-67.569.3)-77.380.5)-(384.7427.5)-(158.2175.9)-1.81.8)-(218.5273.9)-10.210.9)-21.232.4)-70.584.1)-30.535.1)-8.411.3)-(170.5238.4)-0.30.3)-0.70.9)-2.32.4)-1.01.0)-0.30.3) es(Pseudacrobele P , ♀ ±666.746.9 ±20.51.6( ±3.90.2( ±7.20.0( ±5.30.1( ±60.90.3( ±36.83.3( ±32.74.9( ±171.31.3( ±92.57.0( ±17.41.6( ±55.50.7( ±7.50.1( ±13.41.0( ±4.80.7( ±1.80.1( ±2.80.2( ±102.90.5( ±27.12.2( ±21.40.7( ±17.60.0( ±1.20.0( ±3.80.3( ±105.81.1( ±117.23.1( ±135.14.9( ±61.81.1( ±68.41.3( ±78.92.3( ±406.130.3 ±167.012.5 ±1.80.0( ±246.239.2 ±10.50.5( ±26.87.9( ±77.39.6( ±32.83.3( ±9.82.1( ±204.448.1 ±0.30.0( ±0.80.1( ±2.40.1( ±1.00.1( ±0.30.0( el b o Pseudacr ynx)pharynx) eter r Table 1. Morphometrics of Character Labcc'VG or TBody diameterPharynx lengthTail lengthAnal body diameterTail annuliLip region diameterStomaStoma diameterStoma/lips region diameterStoma/stoma diameterCorpusIsthmusBasal bulbBasal bulb diameterBasal bulb length/diameterCorpus:isthmus ratioNerve ring to ant. endExcretory pore to ant. endDeirid to ant. end Nerve ring position(% phar Excretory pore position(% Deirid position(% pharynx)Vulva from ant. endVulva to anusVulva to anus/tail lengthReproductive tract lengthVagina-Postuterine sacUterusSpermathecaOviductOvaryVagina/body diameter-Postuterine sac/body diamUterus/body diameterSpermatheca/body diameteOviduct/body diameter Anim. Syst. Evol. Divers. 35(2), 41-48 43 Taeho Kim, Joong-Ki Park though a long ragged mucro has not been reported from ) ) ) )) ) -23.61.3)-11.20.6)0.5)0.5)-25.81.4)-25.8-46.47.1)-24.61.3)1.8)3.1) calnays sPif.y (iPng.) tvhaersiea sbpileicsi msoe nfas ra, st hae n eevwi dsepnecceie ds.o Pess enuodta jcursotbifey­ udolatus , n2♂ -= ±0.6(22.8 -±0.1(1.2 ±0.9(10.0 -±0.0(0.6 -±0.0(0.4 -±0.1(0.4 ±1.3(24.0 -±0.0(1.3 ±3.2(21.3 ±5.1(39.2 -±1.1(5.5 ±0.9(23.3 -±0.1(1.2 -±0.0(1.8 -±0.3(2.7 lferos m(P Sseouudtha cKroobreeale.s) variabilis is reported for the first time e 236654935830389 ps 3.1.0.0.0.0.4.1.3.2.6.4.1.1.2. 1*Subgenus Bunobus De Ley, Siddiqi and Boström, 1993 ) 2 1 2 24 2 s u ob 2* Pseudacrobeles (Bunobus) pseudolatus n u B (Hernández, 1990) De Ley, Siddiqi and Boström, ( es 1993 (Table 1, Fig. 2) el 4) 4)6) 9) Pseudacrob , n2♀ -±5.00.2(4.95.1)=------ -±23.54.1(20.626. -±1.30.1(1.21.3) -±19.42.9(17.321. -±35.22.0(33.836. -±7.33.3(5.09.7) -±23.05.5(19.126. -±1.40.0(1.41.4) -±2.00.5(1.72.4) -±0.70.0(0.70.7) s2MHPa0sen2ae1tg9tue2enr0d,ro a;aei mcAacxerl-tbp ordeohaboxclae,aat llefimCoedsabhi u(naabBsneny udgdp nsw. s Pioe2eoeb♀uvnñudi-♀ansos-)gilS ,ap a aatUnsunnedistduc i2H hadt♂gaohenoler♂ag,n tB-2áu,g n0asSud1 eoD,er 3umBze:t , uh2 aL1k 0nKe9-1nym9o, 0ferfiyue:teg na1aos:n0l n..Ge 2,,1 l ,1y ,2 mfi9e25o9g. enJ3.t ahgb1n--:. s od from potato farm soil. The two specimens (slide Nos. u olat NIBRIV0000754017 [female] and NIBRIV0000754018 d u [male]) are deposited at the National Institute of Biologi- dacrobeles(Bunobus) pse acrobeles) variabilis , n2♂ -= -±23.80.7(23.324.2) -±1.20.0(1.21.2) -±12.50.8(12.013.1) -±0.60.0(0.60.7) -±0.50.0(0.50.6) -±0.60.0(0.60.6) -±23.10.7(22.623.7) -±1.20.0(1.21.2) -±11.41.2(10.612.3) -±29.42.3(27.831.0) -±5.50.1(5.45.5) -±20.20.5(19.920.6) -±1.60.3(1.41.9) -±1.50.3(1.31.8) -±2.40.1(2.32.5) cdWMDμNaemeoolep ssma oRc.is srnae0uiins tp1refose0ted uimU1m ori0cnnneae4in. lsv 0tetA,he2 sseRr.d 0s aSeu0Aintpe1lyntdeu ,:[i b RmfT5Bleaie7amcobpl6 d luao.ePy0lbf eh1 l-]cKiy.c6 ylao 0olonrig8fned e.adK 4n 0r aooiμ1cnrm0maed1lai ; ct.0 iwsln4e o0 Lnm 2gas0btpah0ole e2cr5sa i[7m;tm o4ver.ay3nel,-sne Et6](r)s9wa l2ailhdlr.y2aee eu ud curved after fixation, C-shaped in females, J-shaped in s e s) variabilis and P (Psseudacrobeles n2 -5.86.6)= -23.023.8)-1.31.4)-22.524.4)-25.125.7)-5.57.7)-18.721.2)-1.21.5)-1.71.8)-8.79.2) 1moienx.c4agctle uμeonpsmdu.y it iCn tnhagugti tc bip1kceh9l yea.a1 ots a-nmmnd2nii 6ddup.- l9hbar%aetoesgd dmioyo;.f i nd aLw nsai ninitdune trlf hiaem lm1o afi.fal7 eel-blsedo2.; d.H4woy ueμi taatmhetd r tm whrterwiigeddoei-eob iinoann dncccydiios,s un1ufrt.arie2edns-s--, ele P , ♀ 5(------ 5( 1( 4( 4( 5( 8( 2( 1( 3( uous with neck. Lip region 6.2-7.1 μm in diameter, with es(Pseudacrob ±6.20. ±23.40.±1.30.±23.41.±25.40.±6.61.±19.91.±1.30.±1.80.±8.90. ±SD(range). bsslaeliiblpgaiaahtrelta rlatayenl d drse, y fdcmououcmnreo ecdited,r p ybah;un attdlw i vcro iops usiabunplbdielve laedwen;i tttprhwar eloa sa ellnnaigdtte. h trCtwa lemo pl iihscpaurslob isscdoc oaomrnpsedaet l.il malSibpeiixss- el an al probolae absent. Amphid aperture small, slit-like. Stoma b e Table 1. Morphometrics of PseudacroTable 1. Continued. Character Ovary/body diameterSpiculesSpicules/anal body diameterGubernaculumGubernaculum/anal body diameter Gubernaculum/spicules(%)Spicule/tail lengthRectumRectum/anal body diameterAnus to phasmid Phasmid position(% tail)Lateral field width Lateral field width/body diameter(%)Cuticle thicknessAnnuli widthMucro Measurements are in μm and in the form m tCKpstlfvceeoruehaoohnrmrplraimegervohr.aoitey rlan huoP smn l.cnn;orh x oaheIdba1 msrtaelorat.pebe2yhdicu:ndd -mn os1gbi,g*1r o uty언poel.hns3e uar. 덕sin lsnn ctE g.b선aitc omxteBarohr충rscrpreao -trp아1iussswenuah .st속7aaeol-sa isl-r rp bs ( cy신2etttulyihh od.lsp칭1lambn.sio nn ug)Ttusr, die ecpi2smar.n* o h is작pjyNecreu op sai은rndet suolsrtc,oi옆si hvt tdr,2iwie e입so,od. a 9ninwl술irldi-sei ,ptin td선d3htia gehn ..rt충a2n cewlCt5 ttg o (itl8신pcaiieycom.lorl a0칭eldndst e- eied t)osaed6dme n r8i vici aasao.meom9trtrlhc n%o epemacotptot aoieeeuodssrrdds-f--,. 44 Anim. Syst. Evol. Divers. 35(2), 41-48 Two Species of Pseudacrobeles in South Korea Fig. 1. Pseudacrobeles (Pseudacrobeles) variabilis (Steiner, 1936) Steiner, 1938. A, Entire female; B, Head region; C, Female neck region; D, Female reproductive system; E, Female posterior region; F, Male posterior region; G, Entire male. am, amphid; an, anus; bb, basal bulb; ca, cardia; co, corpus; cpa, cephalic papilla; cpr, cephalic probolae; de, deirid; ep, excretory pore; gp, genital papil- la; gu, gubernaculum; in, intestine; is, isthmus; lf, lateral field; lpa, labial papilla; lpr, labial probolae; mu, mucro; nr, nerve ring; ova, ovary; ovi, oviduct; ph, phasmid; pus, post-uterine sac; re, rectum; spe, spermatheca; spi, spicule; st, stoma; te, testis; ut, uterus; va, vagina; vu, vulva. Scale bars: A, G 50 μm, B 5 μm, C, D 20 μm, E, F 10 μm. = = = = pus or corpus-isthmus junction, at 61.2-68.5% of pharynx times the body width. Uterus 1.5-1.8 body-diameters long. length. Position of deirids in lateral field at isthmus level, at Spermatheca inconspicuous, 0.8-1.7 times the body width. 68.3-76.6% of total neck length. Oviduct short. Ovary directed posteriorly, with or without Female: Reproductive system monodelphic-prodelphic. double flexure, with a single row of oocytes. Rectum length Vagina 0.3 body-diameters long. Post-uterine sac 0.7-0.9 1.2-1.3 times the anal body diameter. Tail elongated conoid, Anim. Syst. Evol. Divers. 35(2), 41-48 45 Taeho Kim, Joong-Ki Park Fig. 2. Pseudacrobeles (Bunobus) pseudolatus (Hernández, 1990) De Ley, Siddiqi and Boström, 1993. A, Entire female; B, Entire male; C, Female neck region; D, Head region; E, Female reproductive system; F, Female posterior region; G, Male posterior region. am, amphid; an, anus; bb, basal bulb; ca, cardia; co, corpus; cpa, cephalic papilla; de, deirid; ep, excretory pore; gp, genital papil- la; gu, gubernaculum; in, intestine; is, isthmus; lf, lateral field; ll, lateral lip; lpa, labial papilla; mu, mucro; nr, nerve ring; ova, ovary; ovi, oviduct; ph, phasmid; pus, post-uterine sac; re, rectum; spe, spermatheca; spi, spicule; st, stoma; te, testis; ut, uter- us; va, vagina; vu, vulva. Scale bars: A, B 50 μm, C, E-G 10 μm, D 2 μm. = = = with small acute mucro. Phasmids at 33.8-36.6% of tail anteriorly. Spicules curved ventrad, 22.8-23.6 μm long; ma- length. nubrium rounded; calamus as wide as manubrium; without Male: Genital system monorchic. Testis reflexed ventrad hump or velum; with one longitudinal incisure. Gubernac- 46 Anim. Syst. Evol. Divers. 35(2), 41-48 Two Species of Pseudacrobeles in South Korea ulum curved ventrad. Three pairs of precloacal subventral a new species. Journal of Nematode Morphology and Sys- papillae (one pair close to anus level) present. Six pairs of tematics, 4:137-154. post-cloacal genital papillae: one subventral and one lateral Abolafia J, Peña-Santiago R, 2005. Nematodes of the order located anterior to phasmid; one lateral located posterior to Rhabditida from Andalucía Oriental: Pseudacrobeles elon­ gatus (de Man, 1880) comb. n. Nematology, 7:917-926. phasmid; two ventral and one subdorsal located at tail termi- https://doi.org/10.1163/156854105776186415 nus region. Tail conoid, blunt terminus, with spike-shaped Abolafia J, Peña-Santiago R, 2013. Iberian species of the sub- mucro. Phasmid opening at 39.2-46.4% of tail length. genus Bunobus De Ley, Siddiqi & Boström, 1993 (Nemato- Distribution. South Korea, Spain. da, Rhabditida, Cephalobidae), with description of Pseuda­ Habitat. Soil sample from a potato farm. crobeles (Bunobus) rotundilabiatus sp. n. and comments on Remarks. The Korea population is similar to P. (B.) pse­ the subgenus. Zootaxa, 3640:200-212. udolatus in having visibly lateral lips, a short post-uterine Andrássy I, 1968. Fauna Paraguayensis. 2. Nematoden aus den sac, an elongated conoid tail in the female, an acute mucro Galeriewäldern des Acaray-Flusses. Opuscula Zoologica on the tails of both sexes, and in the positions of the nerve Budapest, 8:167-312. ring and excretory pore (both on posterior part of corpus). Andrássy I, 2005. Free-living nematodes of Hungary: Nema- However, our Korean specimens differ from the previ- toda errantia. Vol. I. Hungarian Natural History Museum, ous descriptions of Hernández (1990) and Abolafia and Budapest, pp. 1-518. Peña-Santiago (2013), in terms of body length (574-692 Baermann G, 1917. Eine einfache methode zur auffindung von vs. 400-470 μm in female and 576-608 vs. 343-400 μm in ankylostomum (Nematoden) larven in erdproben. Genee- skundig Tijdschrift voor Nederlandsch-Indië, 57:131-137. male), body thickness (a 19.3-21.9 vs. 15-19 in female De Ley P, Siddiqi MR, Boström S, 1993a. A revision of the ge- and 21.2-24.3 vs. 17-21 in male), tail length (c 11.2-11.8 = nus Pseudacrobeles Steiner, 1938 (Nematoda: Cephalobi- vs. 8.4-9.9 in female and c’ 3 vs. 3.3-4.5 in female and = dae). Part 1. Subgenus Pseudacrobeles grad. n. Fundamen- 2.6-3.4 vs. 2.0-2.5), ratio between corpus and isthmus in = tal and applied Nematology, 16:219-238. males (3.0-3.1 vs. 2.2), spicule length in males (22.8-23.6 De Ley P, Siddiqi MR, Boström S, 1993b. A revision of the vs. 15-20 μm), phasmid position on tail in female (33.8-36.6 genus Pseudacrobeles Steiner, 1938 (Nematoda: Cephalo- vs. 40-42%) and incisures in the lateral field in the male bidae). Part 2. Subgenus Bunobus subgen. n., problemati- (extending over phasmids vs. fading out at phasmid region). cal species, discussion and key. Fundamental and applied Although some morphometric values between our speci- Nematology, 16:289-308. mens and previously described populations are different, the Hernández MA, 1990. Heterocephalobus pseudolatus n. sp. degree of difference is not meaningful and the morpholog- encontrada en Navarra, norte de España (Nematoda, Ceph- alobidae). Boletín de la Real Sociedad Española de Historia ically important characters such as the shape of the head, Natural. Biología, 85:101-106. stoma and tail, and the acute mucro on the tail of both sexes Holovachov O, Boström S, 2006. Description of Pseudacrobe­ are very similar. Pseudacrobeles (Bunobus) pseudolatus is les (Bunobus) arboricola sp. n. (Rhabditida: Cephalobidae) reported for the first time from South Korea. from rotting wood in Roztochya, Ukraine. Journal of Nem- atode Morphology and Systematics, 9:49-54. Holovachov O, De Ley P, 2001. Description of Pseudacrobeles ACKNOWLEDGMENTS (Bunobus) bostromi sp. n. (Rhabditida: Cephalobidae) from rotting wood in Roztochya, Ukraine. Journal of Nematode This work was supported by the National Institute of Bio- Morphology and Systematics, 4:21-30. logical Resources (NIBR) funded by the Ministry of Envi- Kim J, Kim T, Park JK, 2017. Description of Pseudacrobeles ronment (MOE) of the Republic of Korea (NIBR201601201) (Pseudacrobeles) curvatus sp. n. (Cephalobidae: Rhabdit- ida) in South Korea. Journal of Nematology, 49:162-167. and the Marine Biotechnology Program of the Korea Insti- tute of Marine Science and Technology Promotion (KIMST) https://doi.org/10.21307/jofnem-2017-061 funded by the Ministry of Oceans and Fisheries (MOF) (No. Loof PAA, 1964. Free-living and plant-parasitic nematodes from Venezuela. Nematologica, 10:201-300. https://doi. 20170431). org/10.1163/187529264X00042 Schuurmans-Stekhoven JJ, 1951. 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