ZooKeys 5 | 6: 1-36 (2015) A peer-rev iewed open-access journa I doi: 10.3897/zookeys.5 | 6. 10087 RESEARCH ARTICLE #ZooKey http:/ / ZOO keys -pen soft. net Launched to accelerate biodiversity research Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam (Nematoda, Dorylaimida, Aporcelaimidae), with an updated taxonomy of the genus Sergio Alvarez-Ortega', Thi Anh Duong Nguyen??, Joaquin Abolafia', Thi Thanh Tam Vu?, Reyes Pefia-Santiago' | Departamento de Biologia Animal, Biologia Vegetal y Ecologia, Universidad de Jaén, Campus ‘Las Lagunil- las s/n, Edificio B3, 23071— Jaén, Spain 2 Department of Terrestrial Ecology, Zoological Institute, University of Cologne, Ziilpicher Strafse 47b, D-50674 Cologne, Germany 3 Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Vietnam Corresponding author: Sergio Alvarez-Ortega (saortega@ujaen.es) Academic editor: H-P Fagerholm | Received 3 June 2015 | Accepted 17 July 2015 | Published 6 August 2015 http.//zoobank.org/EO86E0F3-OD8A-4E22-8ECF-EA38E04 10BA6 Citation: Alvarez-Ortega S, Nguyen TAD, Abolafia J, Vu TTT, Pefia-Santiago R (2015) Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam (Nematoda, Dorylaimida, Aporcelaimidae), with an updated taxonomy of the genus. ZooKeys 516: 1-26. doi: 10.3897/zookeys.516.10087 Abstract Three new species of Aporcelaimoides from natural habitats in Vietnam are studied, described and illus- trated, including line drawings, LM and/or SEM pictures. Aporcelaimoides brevistylum sp. n. is characteri- zed by its body 1.95—2.90 mm long, lip region offset by deep constriction and 17—18 um broad, ventral side of mural odontostyle 11-14 um long with aperture occupying 62—71% of its length, neck 663-767 um long, pharyngeal expansion occupying 58-66% of total neck length, uterus a simple tube 85-182 um long, pars refringens vaginae absent, V = 55-63, tail short and rounded (34-46 um, c = 49-76, c’ = 0.6-0.8), spicules 67-86 um long, and one ventromedian supplement out the range of spicules. Aporce- laimoides minor sp. n. is distinguished in having body 2.09-2.61 mm long, lip region offset by deep constriction and 19-20 um broad, mural odontostyle 14—16 pm long at its ventral side with aperture occupying 73-84% of its length, neck 579-649 um long, pharyngeal expansion occupying 57-66% of total neck length, uterus a simple tube 44—69 um long, pars refringens vaginae well developed, V = 48-56, female tail very short, rounded conoid or truncate (14-26 um, c = 90-146, c’ = 0.3-0.6), and male un- known. Aporcelaimoides silvaticum sp. n. is characterized by its body 2.09—2.60 mm long, lip region offset by depression and 17—18 um broad, mural odontostyle 11-12 pm long at its ventral side with aperture oc- cupying 60-66% of its length, neck 597-720 um long, pharyngeal expansion occupying 58-64% of total neck length, uterus a simple tube 128-243 um long, pars refringens vaginae well developed, V = 58-60, tail Copyright Sergio Alvarez-Ortega et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 2 Sergio Alvarez-Ortega et al. / ZooKeys 516: 1-26 (2015) short and rounded (27—37 um, c = 67-94, c’ = 0.6-0.7), spicules 64—75 um long, and two or three widely spaced ventromedian supplements bearing hiatus. The genus Aporcelaimoides is restored, its diagnosis emended, and three species of Sectonema, namely S. amazonicum, S. haguei and S. moderatum, transferred to it. An updated list of its species, a key to their identification and a tabular compendium with the most important morphometric features are also presented. Keywords Description, morphology, morphometrics, new combinations, new species, taxonomy, Sectonema, SEM Introduction The genus Aporcelaimoides is an interesting aporcelaimoid taxon, created by Heyns (1965) to accommodate two new species, namely A. probulbum (type species) and A. californicum. \t was originally characterized among other features by its “Spear dory- laimoid, with a large dorsal aperture, but the basal part of the spear much narrower than the lumen of the pharynx, and situated ventrally in the pharynx”. Later, Siddiqi (1995) regarded it as a junior synonym of Sectonema Thorne, 1930, an action that, several years later, was followed by Andrassy (2009). However, this taxonomical deci- sion deserves further analyses since important morphological differences exist between both genera, being especially important those affecting the nature of the stomatal pro- trusible structure. The study of dorylaimid fauna from Vietnam has received poor attention. Several authors (Vu et al. 2010; Nguyen et al. 2011; Gagarin and Gusakov 2012 and 2013a,b; Nguyen et al. 2014) discovered some new species and reported for the first time infor- mation about other known species. It is suggested that Vietnamese dorylaimid fauna might be highly diverse. ‘This is the first contribution in a series devoted to study the aporcelaimid fauna of this Asian country. During a general nematological survey conducted during the last five years to study the diversity of the Vietnamese nematode fauna, several specimens of the genus Aporcelaimoides were collected from natural areas in Vietnam. Their detailed exami- nation revealed they belonged to three unknown forms, which are herein described. Besides, the study of this nematode material has confirmed relevant data to reconsider the identity of the genus Aporcelaimoides. Material and methods Nematodes Nematodes were collected from several natural areas in Vietnam, extracted from soil samples using the methods of Baermann (1917) and Flegg (1967) somewhat modi- fied, relaxed and killed by heat, fixed in 4% formaldehyde, and processed to anhydrous Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam... 3 glycerine following Siddigqi’s (1964) technique. Finally, the specimens were mounted on permanent glass slides to allow handling and observation under LM. Light microscopy Nematodes were measured using a light microscope. Morphometrics included de Man’s indices and most of the usual measurements. The location of the pharyngeal gland nuclei is expressed according to Loof and Coomans (1970) and spicule termi- nology follows Pefa-Santiago et al. (2014). Some of the best preserved specimens were photographed with a Nikon Eclipse 80i microscope and a Nikon DS digital camera. Raw photographs were edited using Adobe® Photoshop® CS. Drawings were made using a camera lucida. Scanning electron microscopy After their examination and identification, a few specimens preserved in glycerin were recycled to their observation under SEM following the protocol by Abolafia and Pefa- Santiago (2005). The nematodes were hydrated in distilled water, dehydrated in a eraded ethanol and acetone series, critical point dried, coated with gold, and observed with a Zeiss Merlin microscope. Taxonomy Aporcelaimoides brevistylum sp. n. http://zoobank.org/0OD05FA79-C8FB-46A8-9496-02F6FID8EGE7 Figs 1-3, 4A—E Material examined. Twelve females and fourteen males from two localities, in variable state of preservation. Measurements. See Table 1. Description. Adult. Moderately slender to slender nematodes of medium size, 1.95-2.90 mm long. Body cylindrical, distinctly tapering towards the anterior end, less so towards the posterior one because the caudal region is rounded. Habitus regu- larly (often strongly) curved ventrad after fixation, usually spiral-shaped. Cuticle three- layered, especially distinguishable at caudal region, where it consists of thinner outer layer bearing very fine transverse striation through the entire body, thicker interme- diate layer with radial striation and thin inner layer; thickness 3—5 um at anterior region, 4—7 um in mid-body and 9.0-12.5 um on tail. Lateral chord 8—20 um wide at mid-body, occupying one-eighth to less than one-fifth (12-18%) of mid-body di- ameter. Three ventral and three dorsal body pores are usually present at level of mural Sergio Alvarez-Ortega et al. / ZooKeys 516: 1-26 (2015) Figure |. Aporcelaimoides brevistylum sp. n. (Line drawing). A Lip region in surface, lateral view B Ante- rior region in median lateral view C Neck D Female, anterior genital branch and vagina E Vagina F Male, posterior body region G Spicule H Lateral guiding piece I Female, posterior body region J Female, entire K Male, entire. Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam... 5 odontostyle-odontophore, their corresponding ducts appearing especially thickened beneath intermediate cuticle layer. Lip region offset by deep constriction, 2.7—3.3 times as wide as high and one-fifth to two-sevenths (18-30%) of body diameter at neck base; lips (under SEM) amalgamated; labial papillae button-like, very percepti- ble and protruding under LM, surrounded by a ring-like annulus (occasionally two annuli), the inner ones at the margin of oral field; cephalic papillae larger than the labial ones, with an oval transverse slit; oral aperture a dorso-ventral, slightly hexagonal orifice, the lip region hence showing a biradial symmetry. Amphid fovea cup-shaped, its opening occupying 9-11 um or one-half to two-thirds (52-64%) of lip region di- ameter. Cheilostom nearly cylindrical, lacking any differentiation. Mural odontostyle attached subventrally and comparatively short, 4.1—5.4 times as long as wide, 0.6—0.8 times as long as lip region diameter, and 0.43—0.61% of body length; aperture 8—9 um long or up to five-sevenths (62—71%) its length. Guiding ring simple, somewhat plicate, at 0.6—0.8 lip region diameters from anterior end. Odontophore linear, rod- like, 3.44.2 times the mural odontostyle length. Anterior region of pharynx enlarging very gradually; basal expansion 9.5—12.6 times as long as wide, 4.6—7.2 times as long as body diameter, and occupying 58-66% of total neck length; gland nuclei obscure in most specimens examined, DN = 50 (n=1) and S,N = 84 (n=1). Nerve ring located at 154-185 um from anterior end or 21-26% of total neck length. Cardia rounded conoid, 10-14 x 14-18 um; a ring-like structure is present surrounding its junction to pharyngeal base. Tail short and rounded; inner core with irregular shape at tail end. Caudal pores two pairs, one lateral, another sub-lateral. Female. Genital system didelphic-amphidelphic, with both branches almost equal- ly and well developed, the anterior 207—254 um long or 9-10% of body length and the posterior 233-300 um long or 9-13% of body length. Ovaries moderately sized, usually not surpassing the sphincter level, the anterior 95-365 um, the posterior 106-— 316 um long; oocytes arranged first in two or more rows, then ina single row. Oviduct 96-124 um long or 1.0—1.4 times the corresponding body diameter, and consisting of a slender part with prismatic cells and a well developed pars dilatata bearing wide lumen that often containing sperm cells inside. Oviduct-uterus junction marked by a sphincter. Uterus a short, simple, tube-like structure 85—182 um long or 1.0—2.1 times the corresponding body diameter, most specimens with abundant sperm cells inside. Uterine eggs ovoid, 153 (n=1) x 79, 85 (n=2) pm, 1.8 (n=1) times as long as wide. Vagina extending inwards 43-57 um or four-ninths to two-thirds (45-65%) of body diameter: pars proximalis 32-44 x 28-34 um, with somewhat sigmoid walls and sur- rounded by weak musculature; pars refringens absent; and pars distalis well developed, 11-14 um long. Vulva a post-equatorial transverse slit. Prerectum 1.8—2.6, rectum 1.0—1.2 anal body diameters long. Male. Genital system diorchic, with opposite testes. In addition to the ad-cloacal pair, situated at 15—20 um from cloacal aperture, there is only one ventromedian sup- plement located out the range of spicules, at 48, 58 (n=2) um from ad-cloacal pair. Spicules distinctly robust and massive, especially in its posterior half, 3.4-4.6 times its maximum width, 1.2—1.7 times the body diameter at level of the cloacal aperture: 6 Sergio Alvarez-Ortega et al. / ZooKeys 516: 1-26 (2015) N Figure 2. Aporcelaimoides brevistylum sp. n. (LM, type population). A Anterior region in surface, lateral view B, E Anterior region in median, lateral view C, D Uterus, containing sperm cells inside F Pharyngo-intestinal junction G Vagina H Spicule I, M Male, caudal region J Male, posterior body region K Female, posterior body region L, N Female, caudal region. Scale bars: 10 um (A, B, E, H, 1); 20 um (C, D, F, G, J-N). dorsal contour regularly convex, ventral contour very weakly concave, with shallow or weak hump and hollow; curvature 126—142°; head occupying 7—21% of spicule total length, its dorsal contour conspicuously curved at its anterior end and longer than the ventral one, which is short and straight; median piece 7.2—-10.9 times as long as wide, occupying 35-50% of spicule maximum width, reaching the posterior tip; posterior end 5—9 um wide. Lateral guiding pieces 13-17 um long, 3.5—5.1 times as long as wide. Prerectum 2.9—4.4, cloaca 1.1—1.3 the corresponding body widths long. Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam... 7 Figure 3. Aporcelaimoides brevistylum sp. n. (LM, other population). A Anterior region in surface, lateral view B, E Anterior region in median, lateral view C Pharyngo-intestinal junction D Pharyngeal expan- sion F Female, posterior body region G Male, caudal region H Spicules I Female, caudal region. (Scale bars: 10 um (A, B, E, G, H); 20 um (C, F, 1); 50 pm (D). Diagnosis. The new species is characterized by its body 1.95—2.90 mm long, lip region offset by deep constriction and 17—18 um broad, ventral side of mural odonto- style 11-14 um with aperture occupying 62—71% of its length, neck 663—767 um long, pharyngeal expansion 387-508 um long or occupying 58-66% of total neck length, uterus a simple tube and 85-182 um long or 1.0—2.1 times the corresponding body di- ameter, pars refringens vaginae absent, V = 55—G63, female tail short and rounded (35—46 um, ¢ = 58-76, c’= 0.6—0.8), male tail similar to that of female (34-42 um, c = 49-69, c’ = 0.60.8), spicules 67-86 pm long, and one ventromedian supplement bearing hiatus. Relationships. In having short mural odontostyle (11-14 um at its ventral side) and pars refringens vaginae absent, the new species is morphologically close to A. cali- fornicum Heyns, 1965 and A. probulbum Heyns, 1965, but it can be distinguished from both species in its smaller (Z = 1.95—2.90 vs LZ = more than 3) and less slender (a = 25-35 vs a2 41) body. Besides, A. brevistylum sp. n. differs from A. californicum in its comparatively longer neck (6 = 3.3—3.7 vs 6 = 7.6), larger mural odontostyle aperture (occupying 62—71% vs one-half of its length), more posterior vulva (V = 55-63 us V= 51), shorter uterus (85—182 um or 1.0—2.1 times the corresponding body diameter vs FI : (I-1) 0°00 OL (I-1) 0°0 FOL See 98-L9 : (8-08) 6'7 ¥ 0'78 3 (98-29) €°S ¥ 9°6L : ypsugy anoidg Cy-vE | OF-SE (OF-9€) 61 # OLE (Z¥-8E) 17 F EOE (CFV) LT F O'BE (9F-SE) SE F OBE ypsugy |e], 0L-9S | S9-SS (S9-19) G1 # £79 (€9-19) O'L ¥ 1°79 (02-96) €°S # L'79 (S9-SS) GE F T'19 Ypsugy vovop/wMIDIy ZEC-OFI | OFI-LII | (Zez-99I) EEF oor | =H) TEL | (BIZ-GPI) Z7F LLL [(GYI-ILD) Z'S1 F 1'871 ysusy wMSeI1q 8S-6h | €9-7S (€S-6F) 0° F LIS (9S-7S) 0°% ¥ EES (85-6) L°7 F LES (€9-¥S) OE F 0'8S snue ye @ 88-99 | 6OI-@Z | (48-69) 69FHLL | (6OI-18) 0°91 F066 | (88-99) TLFHZL | OOI-CZ) 801 F768 Apogprur 3e & S8-9S | 96-04 (ALALECE LVL (Z=U) 88 ‘18 (S8-9S) 66 F 97 (96-04) $6 ¥ S18 oseq Dou Ie “WIC] si ZIY-L8E | 80S-SOF | (ZI¥—Z8E) EI ¥ COP (=U) cP (I=) 68€ (I=) SOP uorsuedxo aha < 689-€99 | LOZ-S69 | (S89-¥99) TI # ZL9 (T=) OFZ (T=) €99 (T=¥) S69 ypsugy YON S cI-Ol | €I-Il | (I-TI) COFETI (SIC EOF LOL (ZI-O1l) LOFOTI (Cl-2)G0F 11 que woy 3m mere S Grey | OS-Py | (8P-Sh) T1F6'SP (0S-9F) 81 F ¥'8h (6F-€h) OT F LS (0S-$y) 17 F SLY ypsugy a10ydoruopO iE: Seiiee Bess at Se bg ey opis [esiop ye x viel | ZI-Gk | I-£1)-c OF ¥ El (LI-FD TL FCS (FI-ED YOF GEL (VI-€l) SOF 61 pu] a,Asoxuopo pernyy © CAS ke || zl LL (ZI-IT) €O FVII (VI-€1) LO FOCI (ZI-I1) €0F STI (€I-11) 90 OI ypu] 2} tons eee - Si=Zie "| -SIRLI (81-81) 010 S°ZT (SI-ZT) $0 FO'ZT (IFZD-COF S91 (SI-Z1) SOF ZI “ureIp uorsar dr] S - €9-6¢ : (19-6S) 0'I ¥ 0°09 : (€9-SS) €°7 F 0°6S A x 80-90 | 80-910 | (8'0-2'0) 00 FZ'0 (8°0-Z'0) 1'0 ¥ Z'0 (80-90) 1'0# Z'0 (80-90) 1'0# Z'0 ra & 69-6 | 92-86 (69-19) 0'Y ¥ 8°49 (SL-L9) O'F ¥ 9°0Z (L9-6¥) LS ¥ 76S (9L-8S) TZ ¥ 8'L9 9 4 Leee | cece | LED) TOFIE q CESLE® |" 1a (S€-67) 67 F VTE (ZE-97) VE F H'87 (CE-L7) LI F 0°67 (€€-G7) TE F T67 e 09°7-S6'I | 06°C-€E'T | (677-1 V7) €0'0 F HHT | (067-097) S10 F LL'T | (09°7-S6'1) 810 F H7'T | (LL'7-€E 7) O10 F 65°7 a Per | Fd PY dSdE OOOl 558 roerey) aSULI [EO], yreg Jeuoney eq my-dnopig yreg Jeuoney ul suex ny) uonepndog on ‘(e8UeI) UOTIIAP plepurIs F USL :WIOJ OY) UT pur ‘(WU UT “T Ida0xa) wr UT s1UdWOINseaYy “U “ds wnpgs1aaLg saplouppas.ody JO srInOWIOYdIO| *| BIqeL Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam... 9 y 1 iii Figure 4. Aporcelaimoides brevistylum sp. n. A-E and A. silvaticum sp. n. F-I (SEM, juvenile). A, C, F Lip region in ventral view B, G, H Lip region in face view D, E, 1 Caudal region in lateral (D) or subventral (E, F) view. Scale bars: 2 um (A-C, F—H); 5 um (D, E, I). about 430 um long or about 5.3 times the corresponding body diameter), compara- tively shorter female tail (c = 58-76, c’= 0.6—0.8 vs c = 126, c’= 1.0), and male present (vs absent). And from A. probulbum in its shorter neck (663-767 um, 6 = 3.3-3.7 vs 883-1011 um, 6 = 3.9-5.2), narrower lip region (17-18 vs about 21 um), and com- paratively longer tail (c = 49-76 vs c = 75-127). Moreover, in having short mural odontostyle (11—14 um at its ventral side) the new species resembles A. haguei (Hunt, 1978), comb. n., but it differs in its smaller general size (ZL = 1.95—2.90 and neck 663-767 um long vs L = 4.67—5.42 and neck 1172-1178 um long), less slender body (a = 25-35 vs a = 52-62), absence (vs pres- ence of rows of minute denticles on stomatal wall, indeed a very relevant feature), pars refringens vaginae absent (vs present), comparatively longer female tail (c = 49-76 us c = 99-118), and male present (vs absent). 10 Sergio Alvarez-Ortega et al. / ZooKeys 516: 1-26 (2015) Type locality and habitat. Vietnam, Dak Lak province, Chu Yang Sin National Park, where it was collected from soil of a pristine forest in October 2012. Other locality and habitat. Vietnam, Lam Dong Province, Bidoup-Nui Ba Na- tional Park, from soil of a pristine forest, collected in June 2013. Type material. Female holotype and seven female and nine male paratypes depos- ited in the nematode collection of the University of Jaén, Spain. One female and one male paratypes deposited in the nematode collection of the Institute of Ecology and Biological Resources, Vietnam. Etymology. The specific epithet is a compound Latin term referring to the short mural odontostyle that characterizes this species. Remarks. The two populations examined are very similar in their morphological features and morphometrics, but some minor differences have been also noted, which are herein regarded as intraspecific variation. Thus, the population from Dak Lak prov- ince shows a shorter mural odontostyle (ventral side 11-13 vs 13-14 um, dorsal side 13-14 vs 14-17 um, in females) and comparatively longer neck (6 = 3.3-3.4 us b = 3.5-3.7). Aporcelaimoides minor sp. n. http://zoobank.org/CD34503A-3436-4A63-A836-7 B87 1E64AG60A Figs 5—7 Material examined. Ten females from three localities, in good state of preservation. Measurements. See Table 2. Description. Female. Moderately slender to slender nematodes of medium size, 2.09—2.61 mm long. Body cylindrical, distinctly tapering towards the anterior end, less so towards the posterior one as the caudal region is very short and rounded to truncate. Habitus regularly curved ventrad after fixation, often spiral-shaped. Cuticle three-layered, especially distinguishable at caudal region: thin outer layer bearing fine transverse striation through the entire body, a much thicker intermediate layer with ra- dial striation, and a thin inner layer; thickness 3.0—4.5 pm at anterior region, 4.5—6.5 um in mid-body and 6.5—9.5 um on tail. Lateral chord 7-13 pm wide at mid-body, oc- cupying one-tenth to less than one-sixth (9—15%) of mid-body diameter. Two ventral and two dorsal body pores are usually present at level of mural odontostyle-odonto- phore, their corresponding ducts appearing especially thickened beneath intermediate cuticle layer. Lip region offset by deep constriction, 2.8—3.3 times as wide as high and one-fifth to less than one-third (21-30%) of body diameter at neck base; lips mostly amalgamated, somewhat angular; papillae perceptible, somewhat protruding. Amphid fovea cup-shaped, its opening occupying 8—10 um or up to one-half (44-50%) of lip region diameter. Cheilostom nearly cylindrical, lacking any differentiation. Mural od- ontostyle attached subventrally, 6.7—7.7 times as long as wide, 0.7—0.9 times as long as lip region diameter, and 0.54—0.72% of body length; aperture 11—13 um long or up to six-sevenths (73-84%) its length. Guiding ring simple, somewhat plicate, at 0.6—0.8 gt Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam... Figure 5. Aporcelaimoides minor sp. n. (Female, line drawing). A Lip region in surface, lateral view B Anterior region in median, lateral view C Neck D Anterior genital branch and vagina E Posterior body region F Vagina G Entire. 12 Sergio Alvarez-Ortega et al. / ZooKeys 516: 1-26 (2015) lip region diameters from anterior end. Odontophore linear, rod-like, irregular at its base, in lateral view with the ventral side longer that the dorsal one (figure 7A, C), and 2.0—2.4 times the mural odontostyle length. Anterior region of pharynx enlarging very gradually; basal expansion 8—12 times as long as wide, 4.1—5.3 times as long as body diameter and occupying 57-66% of total neck length; gland nuclei obscure in most specimens examined, DN = 54 (n=1) and S,N = 92 (n=1). Nerve ring located at 158-177 um from anterior end or 24-31% of total neck length. Cardia rounded conoid, 11-19 x 14-18 um; a ring-like structure is present surrounding its junction to pharyngeal base. Genital system didelphic-amphidelphic, with both branches almost equally and well developed, the anterior 174—207 um long or 7—9% of body length and the posterior 168-220 um long or 7—9% of body length. Ovaries variably sized, the anterior 93-191 um, the posterior 84-175 pm long; oocytes arranged first in two or more rows, then in a single row. Oviduct 73-103 pm long or 0.9-1.1 times the corresponding body diameter, and consisting of a slender part with prismatic cells and a weakly developed pars dilatata. Oviduct-uterus junction marked by a sphincter. Uterus a short, simple, tube-like structure 44—69 pm long or 0.5—0.9 times the corre- sponding body diameter, lacking sperm cells inside. Vagina extending inwards 38-51 um or two-fifths to one-half (43-53%) of body diameter: pars proximalis 25-35 x 15-20 um, with somewhat sigmoid walls and surrounded by weak musculature; pars refringens with two small, triangular to drop-shaped pieces measuring 8-10 x 6-8 um and with a combined width of 14-19 um; and pars distalis short, 3.0—-5.5 pm long. Vulva a transverse slit. Prerectum 1.4—2.1, rectum 0.8—1.1 anal body diameters long. Tail very short and rounded to truncate. Caudal pores two pairs, one sublateral, an- other sub-dorsal. Male. Unknown. Diagnosis. The new species is characterized by its body 2.09—2.61 mm long, lip region offset by deep constriction and 19-20 um broad, mural odontostyle 14-16 um long at its ventral side with aperture occupying 73-84% of its length, neck 579-649 um long, pharyngeal expansion 331—423 um long or occupying 57-66% of total neck length, uterus a simple tube and 44—69 um long or less than (0.5—0.9 times) the cor- responding body diameter, pars refringens vaginae well developed, V = 48-56, female tail very short and rounded to truncate (14-26 um, c = 90-146, c’ = 0.3-0.6), and male unknown. Relationships. ‘This species resembles A. haguei comb. n. in having relatively small mural odontostyle (up to 17 um long) and pars refringens vaginae present. It can be, however, easily distinguished from this in its smaller general size (ZL = 2.09—2.61, neck 579-649 um long vs L = 4.67—5.42, neck 1112-1178 pm long), less slender body (a = 23-33 vs a = 52-62), the absence (vs presence) of rows of minute denticles on stomatal wall), and its much shorter female tail (14-26 um, c’= 0.3—0.6 vs 46-47 um, c’= 0.7). Besides, in having short mural odontostyle (11—14 pm at its ventral side) the new species resembles A. brevistylum sp. n. and A. californicum, but it differs from these in its well developed pars refringens vaginae (vs absent). Moreover, it differs from A. bre- vistylum sp. n. in its shorter neck (579-649 vs 663-767 um), wider lip region (19-20 13 Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam... squauajddns uerpowonus,, Cort [i (SZ-¥9) T'S F ¥'0L eee wpSugy amnoidg (1€-LZ) HT F P67 Yamal (97-LI) ¥'E F OC ypsuay [Fe], (99-96) GF F S19 09-TF (09-Lh) €°S F LTS ypsuay vovOpS/WUMIDIY (€SI-@HL) 9S FBP 90I-€Z (901-28) $6 ¥ 0°26 ypsusy unydeIsIg (8h-Sh) TL F £9F 09-9F (09-95) 1S F TIS snue re (08-69) 8°b F 1°SZ L6-0L (S6-0Z) 9°6 ¥ 0°98 Apoqprur re (6L-S9) 8°S FGI €6-L9 (€6-69) L°6 ¥ 6'E8 aseq pou Ie “WIC (9€¥-€SE) LE F E8E ETH-IEE | (OTH-09E) LZ F 16E TBE “TEE O8€ ‘00F yisue] uorsuedxo peasudreyg (¥89-L6S) OF ¥ S79 6¥9-6LS | (6%9-Z6S) 87 ¥ 979 819 “6S 0¢9 ‘“ZE9 ya8us] 2N (€I-6) 07 F GOL CI-CI (I-Z1I) OL FLTI é ‘YT (Z=¥) SI pus ‘jue woy Sul Surpmsy (1¥-GE) €1 FEOF GE-€E (PC-€¢) LO FTEE (=U) €¢ (T=U) €€ yisuzy aoydoiu0pO Gaaaeyad (Ci=S1) LOF 09 ee Cin c0F eT Canon | a (ean, | GM) SOFT ocenzorrar | oraz | orc | ol apis Jesiop 3 ySsuey a}4so1oOpo yen OpIs PeIIUSA Ye YISuI] aJAIsoyUOpO TeINyy ‘weIp uorsal drT HB REEEEE EEE EEE (LE1-06) 'LI ¥ 0601 — A (L.0-9'0) 0°0# 90 ae £0 Ooo T0Fso | CueEeo | ¥0'CO S (Go-L9) SOLF GGL | 69 | €8 | 9¥I-06 | (LET-06) 7-21 F 0601 oar Parr att 9 (Cyysyorle | se | 9€ | rree | Wrlecoroe | SEOr | q (ce-sc) cF#L0E | & | oc | EE (€€-97) 6° F 8°87 Tseee Ieee le e (8S°7-60'C) ¥C'0 F IE ee | oe 19z-6O%| (INTC HOF VT | LV TET | ¥ee‘oo'?| ZT T Poy i ee ERD sadAjereg sodAereg | adAojoxy yreg Jeuoney Suonyg np rae ae oe Sree key uonepndog ‘u ‘ds mnsyvazis “y ‘u ‘ds Loum “py saisedg ‘(adues) uo -eIAOp prepurIs F ULI :WIOJ oy) UT pur ‘(uU UT “7 Iddoxa) wil ur syUsWAINseay “U “ds wnouvazs ‘py pue ‘u ‘ds sour saproupjazsody Jo soInsWOYdIOWY *7 BIqeL 14 Sergio Alvarez-Ortega et al. / ZooKeys 516: 1-26 (2015) Figure 6. Aporcelaimoides minor sp. n. (LM, female, type population). A Anterior region in surface, lateral view B, E Anterior region in median, lateral view C Neck region D Genital system F Pharyngo- intestinal junction G Vagina H Posterior body region I, J Caudal region. Scale bars: 10 um (A, B, E-G, I, J); 100 um (C); 50 um (D); 20 um (H). vs 17-18 um), smaller mural odontostyle aperture (occupying 73-84% vs 62-71% its length), shorter female tail (14-26 um, c = 90-146, c’ = 0.3-0.6 vs 35-46 pm, c = 58-76, c’ = 0.6-0.8), and male absent (vs present). And from A. californicum in its shorter (Z = 2.09-2.61 vs L = 5.53) and less slender (a = 23-33 vs a = 75) body, larg- er mural odontostyle aperture (occupying 73-84% vs one-half of its length), shorter uterus (44—69 um long or less than one body diameter vs about 430 um long or about 5.3 times the corresponding body diameter), and shorter female tail (14—26 um, c’= 0.3-0.6 vs 44 um, c’= 1.0). Type locality and habitat. Vietnam, Bac Giang Province, Tay Yen Tu Natural Reserve, collected from soil in a pristine tropical forest, in July 2008. Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam... 15 Figure 7. Aporcelaimoides minor sp. n. (LM, female, other populations). A, B, F (Population from Cao Bang Natural Reserve) C—E, G, H (Population from Chu Yang Sin National Park) A, C Anterior region in median, lateral view B Pharyngeal expansion D Anterior region in median, ventral view E Vulva in ventral view F—H Caudal region. Scale bars: 10 um (A, C, D, E, H); 50 um (B); 20 pm (F, G). Other localities and habitats. Vietnam, Cao Bang Province, Cao Bang Natural Reserve (GPS coordinates: 22°34'07"N and 105°52'34"), in a tropical evergreen forest soil in association with Dipterocarpus sp. and Cinnamomum sp., collected in 2013. Dak Lak province, Chu Yang Sin National Park, in October 2012. Type material. Female holotype and one female paratype deposited in the nema- tode collection of the University of Jaen, Spain. One female paratype deposited in the nematode collection of the Institute of Ecology and Biological Resources, Vietnam. Etymology. The specific epithet means ‘small’ and refers to the comparatively small general size of the new species. Remarks. In spite of it was collected from three localities, the material examined is very similar in its main morphological features and morphometrics. Nevertheless, some differences have been also observed, especially affecting the female tail shape as some specimens show a short and rounded-conoid caudal region whereas it becomes extremely short and truncate in other individuals. 16 Sergio Alvarez-Ortega et al. / ZooKeys 516: 1-26 (2015) Aporcelaimoides silvaticum sp. n. http://zoobank.org/C8EAC3A3-EB59-485C-86DC-1471D682731A Figs 4F—I, 8, 9 Material examined. Iwo females and four males, in variable state of preservation. Measurements. See Table 2. Description. Adult. Moderately slender to slender nematodes of medium size, 2.09—2.60 mm long. Body cylindrical, distinctly tapering towards the anterior end, less so towards the posterior one because the caudal region is rounded conoid. Habitus regularly curved ventrad after fixation, to a more or less open C, occasionally more curved at posterior body region, spiral-shaped in only one male specimen. Cuticle three-layered, especially visible distinct at caudal region, consisting of thin outer layer bearing fine transverse striation through the entire body, a much thicker intermedi- ate layer with radial striation, and a thin inner layer; thickness 2.5—4.0 tm at anterior region, 5—6 um in mid-body and 8-10 um on tail. Lateral chord 7-12 um wide at mid-body, occupying one-tenth to one-eighth (10-12%) of mid-body diameter. Three ventral and three dorsal body pores are usually present at level of odontostyle-odonto- phore, their corresponding ducts appearing especially thickened beneath inner cuticle layer. Lip region visibly narrower than adjacent body, offset by depression, 2.2—2.6 times as wide as high and one-fifth to one-fourth (19-27%) of body diameter at neck base; lips (under SEM) amalgamated; papillae button-like, the inner labial ones rather close the margin of oral field and surrounded by one or two ring-like annuli, whereas the outer labial ones are surrouned by only one annulus and the cephalic ones lack a such differentiation; oral aperture a dorsoventral, nearly hexagonal orifice, the lip region hence showing a biradial symmetry. Amphid fovea cup-shaped, its opening at level of cephalic depression and occupying 12—13 pm or up to three-fourths (72-75%) of lip region diameter. Cheilostom nearly cylindrical, lacking any differentiation. Mu- ral odontostyle attached subventrally and comparatively short, 4.5—4.9 times as long as wide, 0.6—0.7 times as long as lip region diameter, and 0.44—0.54% of body length; aperture 7-8 um long or up to two-thirds (60-66%) its length. Guiding ring simple, somewhat plicate, at 0.5—0.7 lip region diameters from anterior end. Odontophore linear, rod-like, 3.8, 4.1 (3.5, 3.7 in males, n=2) times the odontostyle length. An- terior region of pharynx enlarging very gradually; basal expansion 8.3—11.0 times as long as wide, 5.0—5.8 times as long as body diameter, and occupying 58-64% of total neck length; gland nuclei obscure in all the specimens examined. Nerve ring located at 139-169 um from anterior end or 23-26% of total neck length. Cardia rounded conoid, 10-16 x 12-18 um; a ring-like structure is present surrounding its junction to pharyngeal base. Tail short, rounded to rounded conoid, its inner core bearing a fin- ger-like projection at tail end. Caudal pores two pairs, one lateral, another sub-lateral. Female. Genital system didelphic-amphidelphic, with both branches almost equal- ly and well developed, the anterior 246, 387 pm long or 10, 15% of body length and the posterior 301 pm long or 12% (n=1) of body length. Ovaries moderately sized, usually not surpassing the sphincter level, the anterior 82, 119 pm, the posterior 66, Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam... 17 Figure 8. Aporcelaimoides silvaticum sp. n. (Line drawing). A Lip region in surface, lateral view B An- terior region in lateral, median view C Neck D Female, posterior body region E Female, anterior genital branch and vagina F Spicule G Lateral guiding piece H Vagina I Female, entire J Male, entire K Male, posterior body region. 18 Sergio Alvarez-Ortega et al. / ZooKeys 516: 1-26 (2015) 103 um long; oocytes arranged first in two or more rows, then ina single row. Oviduct 99-107 um long or 1.2, 1.3 times the corresponding body diameter, and consisting of a slender part with prismatic cells and a moderately developed pars dilatata with visible lumen but no sperm cell. Oviduct-uterus junction marked by a sphincter. Uterus a short, simple, tube-like structure 128-243 um long or 2.1, 2.8 times the correspond- ing body diameter, one female containing abundant sperm cells inside. Vagina ex- tending inwards 31, 32 um or about three-eighths (36%, n=1) of body diameter: pars proximalis 23, 24 x 25, 26 um, with somewhat sigmoid walls and surrounded by weak musculature; pars refringens with two small, triangular to drop-shaped pieces measur- ing 5 x 4, 5 um and with a combined width of 9, 10 um; and pars distalis 1.0, 1.5 um long. Vulva a post-equatorial transverse slit. Prerectum 2.3, 2.5, rectum 0.8, 1.2 anal body diameters long. Male. Genital system diorchic, with opposite testes. In addition to the ad-cloacal pair, situated at 16-19 um from cloacal aperture, there is a series of two or three widely spaced (22—42 um apart) ventromedian supplements, the posteriormost of which lying out the range of spicules, but very close to the spicules end, being situated at 42—63 um from ad-cloacal pair. Spicules relatively robust, 3.5—4.6 times its maximum width, 1.3—1.6 times the body diameter at level of the cloacal aperture: dorsal contour regu- larly convex, ventral contour bearing weak hump and hollow; curvature 140-1439; head occupying 8—10% of spicule total length, with both contours nearly straight, and its dorsal side longer than the ventral one; median piece 6.5—8.3 times as long as wide, occupying 45-54% of spicule maximum width, reaching the posterior tip; posterior end 5—6 pm wide. Lateral guiding pieces 19-23 um long, 6.4—7.8 times as long as wide. Prerectum 3.0—3.3, cloaca 1.2—1.4 times the corresponding body width long. Diagnosis. The new species is characterized by its body 2.09—2.60 mm long, lip region offset by depression and 17-18 um broad, mural odontostyle 11-12 um long at its ventral side with aperture occupying 60-66% of its length, neck 597-720 um long, pharyngeal expansion 353-452 um long or occupying 58-64% of total neck length, uterus a simple tube and 128-243 um long or 2.1—2.8 times the corresponding body diameter, pars refringens vaginae well developed, V = 58-60, female tail short and rounded to rounded conoid (31-37 um, c = 69-83, c’= 0.7), male tail similar to that of female (27-31 um, c = 67-94, c’ = 0.6-0.7), spicules 64-75 um long, and two or three widely spaced ventromedian supplements bearing hiatus. Relationships. The new species differs from its relatives by its lip region offset by depression (vs constriction). Besides, in having pars refringens vaginae and short mural odontostyle (11—12 um long at its ventral side), A. si/vaticum sp. n. is morphologically similar to A. haguei comb. n. and A. minor sp. n., but it can be distinguished from them in its narrower lip region (17—18 vs equal or 19 um or more) and more posterior vulva (V = 58-60 vs Vup to 57). It also differs from A. haguei comb. n. in its smaller general size (L = 2.09—2.60, neck 597-720 um long vs L = 4.67—5.42, neck 1112- 1178 um long), less slender body (a = 28-33 vs a = 52-62), absence (vs presence) of rows of minute denticles on stomatal wall), shorter female tail (31-37 vs 46-47 um), and male present (vs absent). And from A. minor sp. n. in its shorter mural odontostyle Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam... Figure 9. Aporcelaimoides silvaticum sp. n. (LM). A Female, entire B Male, entire C Anterior region in surface, lateral view showing four lateral pores D, E Anterior region in median, lateral view F, G Anterior region in surface, lateral view showing the amphid fovea H Pharyngo-intestinal junction I Vagina J Fe- male, posterior body region K Male, posterior body region L Female, posterior genital branch M Male, caudal region N Female, caudal region O Spicules P Sperm cells. Scale bars: 500 um (A, B); 20 um (C); 10 pm (D-F, H, I, M—P); 5 um (G); = 50 um J-L). 20 Sergio Alvarez-Ortega et al. / ZooKeys 516: 1-26 (2015) (11-12 vs 14-16 um at its ventral side) with smaller aperture (occupying 60-66% vs 73-84% of its length), longer female tail (27-31 um, c = 67-94, c’= 0.6-0.7 vs 14-26 um, c = 90-146, c’= 0.3-0.6), and male present (vs absent). Finally, the new species also resembles A. brevistylum sp. n. in having short mural odontostyle, but it differs from this in its well developed (vs absent) pars refringens vaginae and higher number of ventromedian supplements (two or three vs one). Type locality and habitat. Northern Vietnam, Cuc Phuong National Park, where the new species was collected from soil of a pristine tropical forest in 2009. Type material. Female holotype and one female and three male paratypes, deposited in the nematode collection of the University of Jaen, Spain. One male paratype deposited in the nematode collection of the Institute of Ecology and Biological Resources, Vietnam. Etymology. ‘The specific epithet is a Latin term meaning “from the jungle’, and refers to the habitat where the species dwells. On the taxonomy of Aporcelaimoides As mentioned in the introductory section, the identity of Aporcelaimoides has been mat- ter of some controversy. In his original description of this genus, Heyns (1965) high- lighted the differences between it and Sectonema, mainly based on the nature of the stomatal protrusible structure, “a dorylaimid spear which is set ventrally ... similar in position to the mural tooth of Sectonema”, putting hence emphasis on the existence of a large dorsal aperture in the protrusible structure of Aporcelaimoides and the absence of a such aperture in the mural tooth of Sectonema. Heyns (op. cit.) also noted that “the basal part of the spear (is) much narrower than the lumen of the pharynx (stoma)” [text between brackets incorporated by the authors]. Subsequent contributions by Andrassy (1976) and Jairajpuri and Ahmad (1992) assumed Heyns’ point of view. Siddiqi (1995), however, stated (p. 99) that “...Since there is a great variation in the mural tooth of Sectonema (see Siddiqi 1984), there is no justification for holding Aporcelaimoides as a valid genus”. And, later, Andrassy (2009) followed Siddigi’s opinion. Very recently, Pefa-Santiago and Alvarez-Ortega (2014a) redescribed S. ventrale Thorne, 1930, the type species of Sectonema, and conclude that (p. 1103) “the pro- trusible structure of Sectonema, as observed in its type species, is not a typical mural tooth as seen in nygolaims, but a reduced odontostyle with its base occupying most (if not whole) the stomatal lumen”. It means that mural odontostyle of Aporcelaimoides significantly differs from the reduced odontostyle of Sectonema. Thus, Siddiqi’s (1995) action might be not well supported as there are morphological arguments to separate both genera and to restore Aporcelaimoides as valid genus. Unfortunately, there is no molecular information of the latter, which would be especially useful to confirm the morphological data. A revised diagnosis of Aporcelaimoides as well an updated list of its species, three of them transferred from Sectonema, and a key to their identification are given in the fol- lowing. Besides, a compendium of their main morphometrics is presented in Table 3. 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Slender to very slender nematodes (a = 23-75) of medium to large size, 1.95-5.66 mm long. Cuticle three-layered, especially obvious at caudal region, with the intermediate layer more refringent and thicker than the outer and the inner ones. Oral aperture a dorso-ventral, nearly hexagonal slit. Lip region offset by a more or less distinct constriction, but by depression in A. silvaticum sp. n. Mural odonto- style attached subventrally, comparatively short and with wide aperture, often occu- pying more than one-half its length. Guiding ring simple and plicate. Odontophore rod-like. Pharynx enlarging gradually, with basal expansion occupying three-fifths to two-thirds of total neck length. Female genital system didelphic-amphidelphic; pars refringens vaginae present or absent; and vulva a transverse slit. Tail similar in both sexes, short, rounded conoid, rounded or truncate. Spicules dorylaimoid, well de- veloped. Ventromedian supplements in low number (0-4), widely separated, always with pre-cloacal space (hiatus). Relationships As mentioned, Aporcelaimoides is morphologically very similar to Sectonema, from which it differs in the nature of the stomatal protrusible structure. It can be easily distinguished from the typical species of Sectonema, for instance S. ventrale — the type species of the genus, recently re-described by Pefia-Santiago and Alvarez-Orte- ga (2014a) — in having a mural odontostyle attached to the ventral side of stoma (vs a reduced axial odontostyle), much narrower than (vs occupying the whole) stomatal lumen, with (in lateral view) its dorsal and ventral sides parallel and dis- tinctly perceptible (vs dorsal side nearly lost) and a perceptible dorsal aperture often occupying more than half of its total length (vs nearly the total odontostyle length). Besides, Aporcelaimoides compares to other atypical species of Sectonema, for instance S. demani Altherr, 1965 (see recent description by Pefia-Santiago and Alvarez-Ortega 2014b) and S. septentrionale Pena-Santiago & Alvarez-Ortega, 2015, which are characterized by having a mural tooth (a protrusible structure lacking a distinct aperture, resembling that found in nygolaims) with asymmetrical sides as (in lateral view) the dorsal side is visibly sigmoid and distinctly longer than the ventral one. List of species Type species Aporcelaimoides probulbum Heyns, 1965 = Sectonema probulbum (Heyns, 1965) Siddigi, 1995 Three new species of the genus Aporcelaimoides Heyns, 1965 from Vietnam... 23 Other valid species Aporcelaimoides amazonicum (Siddiqi, 1995), comb. n. = Sectonema amazonicum Siddiqi, 1995 Aporcelaimoides brevistylum sp. n. Aporcelaimoides californicum Heyns, 1965 = Sectonema californicum (Heyns, 1965) Siddiqi, 1995 Aporcelaimoides haguei (Hunt, 1978), comb. n. = Sectonema haguei (Hunt, 1978) Andrassy, 2009 Nygolaimium haguei Hunt, 1978 Aporcelaimoides minor sp. n. Aporcelaimoides moderatum (Siddiqi, 1995), comb. n. = Sectonema moderatum Siddiqi, 1995 Aporcelaimoides silvaticum sp. n. Remarks on some species A. amazonicum: The nature of the stomatal protrusible structure, a mural odontostyle, supports its inclusion in Aporcelaimoides rather than in Sectonema. A. haguei: Andrassy (2009) transferred this species to Sectonema from Nygolaimium, but the mural odontostyle that characterized this species justifies its transference to Aporcelaimoides. A. moderatum: The general morphology of this species, very especially that of the sto- matal protrusible structure, fits the updated concept of Aporcelaimoides and justifies its transference to this genus. Key to identification of Aporcelaimoides species — Lip region nearly continuous with the adjacent body......... silvaticum sp. n. Eis PEGTO MOLISE: D YMC ORS ERVCUIONT A tes udntraenn neath esideepsnsaiptbAloonmadeaupn de caapentesyee te 2 PATS VCPTINGENS VAGINGE ADSENE boul vv euds ove conto nn Achevees ot oVeneyudesedquchndiueensssseouced 3 DAS Ve TIN CEN S WAR INEG DICSEIL wah ocrautennaserdettodivak aswel Aida tae wtteto dich diSaeetse, 5 Larger (body 5.53 mm long) and more slender (a = 75) nematodes; neck comparatively shorter (4 = 7.6); mural odontostyle aperture occupying one- Hale Wits TEMG thts ital GrASe rine, ise oatisplicwealde Ec olnuctdalacelisensyl rete ls californicum Smaller (body up to 4.75 mm long) and less slender (a up to 63) nematodes; neck comparatively longer (4 up to 5.4); mural odontostyle aperture occupy- ine 2 7 ouits Tevet hs: male preseiitinnss.sttiesc toon ntsot snot onseme eater stobarest oats 4 Body 1.95-—2.90 mm long and less slender (a = 25-35); shorter neck (663— 767 um long, 6 = 3.33.7); lip region 17—18 um wide; comparatively longer feat Gee hes) cae. bas oy Beales evan cas een’ ruehie Bed brevistylum sp. n. 24 Sergio Alvarez-Ortega et al. / ZooKeys 516: 1-26 (2015) < Body 3.35—4.75 mm long and more slender (a = 41-63); longer neck (883- 1011 um long, 6 = 3.9-5.2); lip region about 21 um wide; comparatively SOREL Cail Cee / SMH hn ho oevac Sov euvecvecevex vo sevunee coves dosaoeveloauweween probulbum 5 iyLipcaleOCOnitOStle Hd AIL ON CGEM O Le vinta shactteatssttognaittonrathtig nhaslaegiaehay pha’ 6 = Miuaraltodontostyierinp. tor Sura LONG. b sasesaar. sys eceonsvoneslsa eurouiagn'eoopyaletub puignccng gh Ti 6 Smaller general size (body 3.30-3.34 mm, neck 733-991 um long); more slender body (a = 43-53); mural odontostyle aperture occupying 80-85% its length; vulva more anterior (V = 53); female tail 38 um long; male present .... Re FR IE | bh. depo ame I oe tient Sr lean Dey Simi ie se ts amazonicum comb. n. = Larger general size (body 4.34—5.66 mm, neck 1113-1348 um long); less slender body (a = 37-38); mural odontostyle aperture occupying 66-75% its length; vulva more posterior (V = 55-59); female tail 53-54 um long; male ADSENIG Me ere ete a ee ee ee ee moderatum comb. n. 7 Smaller general size (body 2.09-2.61 mm, neck 579-649 um long); more obese body (a = 23-33); stomatal walls lacking rows of minute denticles; mu- ral odontostyle occupying 73-84% its length; shorter tail (14-26 um long, c’ SPD). © Jere hacels Means. sssnr eo encanad attonsanenes eoboaeteattnar ea tAaneap Masaka roeneats minor sp. n. — Larger general size (body 4.67—5.42 mm, neck 1112-1178 um long); more slender body (a = 52-62); stomatal walls bearing rows of minute denticles; mural odontostyle aperture occupying 69% its length; longer tail (46-47 um VOTRE REAR OTB) So sngtleool a aleubatisiarsnt oitacmsbandtatsbin ciety beaiteap pratten hae @eeoh haguei comb. n. Acknowledgements The authors are especially grateful for the financial support received from the pro- ject entitled Aporcelaimidae Mundi: Revision de la familia Aporcelaimidae Heyns, 1965 (Nematoda, Dorylaimida) (ref. CGL2012—33239; co-financed FEDER). The first au- thor is a postdoctoral researcher at the University of Jaén, originally supported by a programme of the University of Jaén and now by the above project. SEM pictures were obtained with the assistance of technical staff and equipment of “Centro de Instrumen- tacién Cientifico-Técnica (CICT)’ from University of Jaén. The second author thanks to the directors of Cuc Phuong National Park, Chu Yang Sin National Park and Cao Bang Nature Reserve for issuing relevant permits. This research was partially supported by the German Academic Exchange Service (DAAD), the Zoological Institute (University of Cologne) and IDEAL-WILD. 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