Journal of Nematology 17(1):29-37. 1985. © The Society of Nematologists 1985. Dolichodorus miradvulvus n. sp. (Nematoda: ) With a Key to Species

GROVER C, SMART, JR., AND NGUYEN B. KHUONG 2

Abstract: Dolichodorus miradvulvus n. sp. from Anubias nana Engler in Florida is described and illustrated. The female is characterized by deep grooves in the cuticle on the ventral surface just anterior and posterior to the vulva, and by transversely elongate pouches anterior and posterior to the vulva. Both sexes have a constricted area of the stylet shaft just anterior to the knobs, and on the male the intersection of the lateral field and bursa appear sclerotized. Key words: , morphology, new species, Anubias nana, SEM.

In June 1982, soil and plant samples of (DGO) = 4.8 ttm (3.4-6 ~tm); anterior end Anubias nana Engler from a commercial to center of median bulb = 167 ttm (156- aquarium plant nursery in Florida con- 180 gm); to excretory pore = 173 tim (157- tained specimens of a new species of Doli- 196 tim); hemizonid to excretory pore = chodorus. The was highly patho- 29 #m (21-37 #m); anal body width genic to A. nana (14). This report presents (ABW) = 31 /zm (26-37/zm); tail = 63 ~tm a description of the new species and a taxo- (57-69 ttm). nomic key to the 13 species of the genus. Holotype (female): L = 2,391/xm; width -- 36#m;a=67;b= 10;c=36;v=54;sty- MATERIALS AND METHODS let = 107 #m (conus 69, shaft 38); DGO = obtained from the original 4.7 ttm; anterior end to center of median sample and from a population reared on bulb-- 158 #m, to excretory pore = 170 corn (Zea mays L.) were killed and fixed in tim; excretory pore to hemizonid = 28 tim; formalin : propionic acid (4:1), infiltrated ABW = 27 #m; tail = 66 #m. with glycerine (13) and mounted in dehy- Description: Body slightly curved after drated glycerine. Measurements and illus- fixation. Lip region with 9-11 annules, off- trations were made from living, quiescent set by deep constriction (Figs. 1A, 3A). Ce- specimens in temporary water mounts. phalic framework with basal plate heavily Living specimens were prepared for scan- sclerotized (Fig. 3A). Perioral disc promi- ning electron microscopy (SEM) by the nent, distinctly raised (Figs. 1A, 3A). Lip method of Stone and Green (15), coated region with four lobes, lateral divisions with gold or gold-palladium, and examined often not distinct (Fig. 3C). Amphid open- in a Hitachi $450 SEM. ing elongate laterally 3 x 1 tim (Fig. 3C). Styler conus 60-66% of stylet length; stylet Dolichodorus miradvulvus n. sp. shaft with a short constricted area imme- (Figs. 1-5) diately anterior to stylet knobs (Fig. 1A). Species name from Latin. Mira = unusu- Stylet knobs rounded posteriorly, anterior al or extraordinary; ad = near; vulvus = surfaces inclined (Fig. 1A). Nerve ring near vulva; hence, unusual or extraordinary near middle of isthmus. Excretory pore variable the vulva. in position, from anterior end of median Females. Measurements of paratypes (20): bulb to nerve ring, usually opposite or near L = 2,414 #m (2,088-2,699/zm); width = median bulb. Hemizonid (Figs. 1A, 3E) 39/sm (34-45/~m); a = 62 (54-71); b = 9.1 about 29 #m (14-23 annules) posterior to (7.8-10.7); c = 38 (34-45); v = 54 (50-57); excretory pore. Esophagus with short, stylet = 110 /xm (105-120 #m) (conus = swollen procorpus, distinctly constricted at 67 tim [65-71 ttm]; shaft = 42/zm [37-49 median bulb (Figs. 1A, 3E). Basal bulb tim]); dorsal esophageal gland orifice large, slightly overlapping intestine ven- trally. Esophagointestinal valve large, Received for publication 20 April 1984. sometimes obscure. DGO 4.8 #m from sty- Florida Agricultural Experiment Stations Journal Series let. Esophageal lumen large, well cuticu- No. 5525. larized from stylet base to valve of median 2 Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, bulb, reduced in size posterior to valve. Gainesville, FL 32611. Vulva a transverse slit in a submerged oval 29 30 Journal of Nemato~y, Volume I7, No. I, January 1985 \ area with pouches anteriorly and poste- pore = 159 #m (146-176 #m), to center of riorly (Figs. 3G; 5A, D) which appear in median bulb= 154 ~m (145-167 gm). lateral view as sclerotized accessory pieces Spicules = 49 tzm (45-52 ~m); gubernac- (Fig. 3F). Tissue inside the pouches ap- ulum = 27 t~m (25-28 ~m); ABW = 20 gm pears ridged (Fig. 5B) but may be the result (18-22 t~m); tail = 30 #m (28-33 ~m). of shrinkage when subjected to vacuum Allotype (male): L = 2,011 t~m; width = pressure. Interior of vagina with strength- 30 gm; a = 67; b = 8.7; c = 69; stylet = 104 ening ridges (Fig. 5C, D) which appear ser- #m; head end to excretory pore = 152 ~m, rate by light microscopy (Fig. 2C). Cuticle to center of median bulb = 153 ~m; ex- on ventral surface anterior and posterior cretory pore to hemizonid = 27 gm; spic- to the vulva bearing up to 10 deep grooves ules = 45 t~m; gubernaculum = 27 t~m; separated by two or three annules (Figs. ABW = 20 #m; tail = 29 Urn. 2C; 3F, G; 5D). Gonads two, outstretched Description: Body similar to female but (Fig. 2A, B). Spermatheca prominent, ob- slightly smaller. Lip region with 9-11 an- long. Cuticle 2.1-2.6 ~m thick at median nules, well offset. Perioral disc prominent, bulb, 4-5 ~m thick at mid body, and 3.5- raised and somewhat angular (Figs. 1B, 3B, 4 tzm thick in anal region. Annules 1.5- 4A). Nerve ring, excretory pore, and hemi- 1.7 t~m wide at level of median bulb, about zonid as for female. Posterior end of body 1 gm at mid body, and 1.3-1.5 gm im- curved ventrally, lateral field prominently mediately anterior to anus. Lateral field raised (Fig. 4B). Tail terminus usually bi- raised, areolated, with three incisures (Fig. furcate (Fig. 4B, D, E). Two lateral lobes 5F); occasionally five incisures were ob- of bursa very large, usually rolled or curved served at mid body and more posteriorly inward with dentate margins (Fig. 4B, C, (Fig. 3D). The central incisure terminates D). Raised lateral field is so thick that the at the phasmid; the others terminate at intersection of lateral field with bursa ap- about 55 #m anterior to anus. Anteriorly, pears heavily sclerotized and is seen easily the central incisure ends about 10 annules in lateral, ventral, and dorsal views (Figs. (9-10 gm) or more from the head constric- 1E, 4F). Testis outstretched (Fig. 1C, D), tion; the outer incisures end about 14 an- more than half the body length. Spicules nules (21 urn) anterior to the center of the almost straight, distal ends pointed. Gu- median bulb. Phasmids at end of central bernaculum with distal end rounded (Fig. incisure about mid tail. Tail 63 #m, with a 4D) and curved dorsally (Fig. 1F). smooth terminal portion 8-10 ~m long. Holotype: Tray 5, Slide 14, University of Males. Measurements ofparatypes (12): L = Florida Nematode Collection, Gainesville, 1,898 t~m (1,831-2,017 #m); width = 30.5 Florida. From population increased on corn ~m (26-37 ~m); a = 62 (49-73); b = 7.8 in a greenhouse. (7-9); c=63 (52-70); stylet= 107 gm AlIotype: Tray 5, Slide 15, same data as (100-112 gm); head end to excretory holotype.

FIG. 1. Dolichodorusmiradvulvus n. sp. A) Anterior portion of female. B) Anterior portion of male. C) End of male gonad. D) Enlargement of apparent seminal vesicle portion of male gonad. E) Male tail showing sclerotized-appearing junction of bursa and body. F) Male tail showing spicules and gubernaculum. FiG. 2. Dolichodorusmiradvulvus n. sp. A) Female gonad. B) Enlargement of spermatheca portion of female gonad. C) Vulval region showing deep grooves and pouches anterior and posterior to vulva, strengthening ridges (serrate appearance) in the vagina and muscles attached to the vaginal wall and body wall. D) Female tail, ventral view. E) Female tail, lateral view. Note differences in length of slender portion. F)Juvenile tail showing gradual tapering. G) Juvenile tail showing abrupt tapering. FIG. 3. Dolichodorus miradvulvus n. sp. (A-D, G = SEM; E, F = LM). A) Labial region of female with constriction and elevated oral disc. B) Labial region of male with constriction and elevated oral disc. C) En face view of female showing four lobes, oral disc, and prominent laterally elongate amphid openings (note secretions). D) Lateral field with five incisures in posterior region of female (fifth incisure around curvature not seen). E) Esophageal region of female. Note that esophagus overlaps intestine ventrally. F) Vulval region of female. Note deep grooves and pouches (which appear as sclerotized accessory pieces) anterior and posterior to vulva. G) Vulval region of female. Note submerged vulva, pouches anterior and posterior to vulva, and deep grooves anterior to vulva. Dolichodorus miradvulvus n. sp.: Smart, Khuong

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Paratypes: Tray 5, Slides 16-20 contain- 2. Cuticle anterior and posterior to ing four females and four males, University vulva without deep grooves ...... : 3 of Florida Nematode Collection, Gaines- 3. Female tail tapering gradually from ville, Florida; 17 slides containing eight fe- anus to tip; male with large hypo- males and nine males, and a vial containing ptygma ...... D. longicaudatus (3) many males, females, and juveniles in the 3. Female tail suddenly narrowing be- authors' possession; USDA Nematode Col- tween anus and tip; male without lection, Beltsville, Maryland; Slide Nos. large hypoptygma ...... 4 T-323 lp, one female; T-3232p, one male; 4. Excretory pore opposite median and Vial No. T-234p, five females, five bulb ...... 5 males, and five juveniles; and Rothamsted 4. Excretory pore posterior to median Experimental Station, Harpenden, Hert- bulb ...... 7 fordshire, England; two slides containing 5. Female T/ABW ratio 3; body less three females and two males. than 2 mm long ...... D. nigeriensis (10) Type host and locality: Anubias nana En- 5. Female T/ABW ratio 2 or less; body gler growing in sand in an aquarium plant more than 2 mm long ...... 6 nursery at Stuart (Martin County), Florida, 6. Lip region cushion-shaped; ante- described as Township 38 South, Range rior cuticle tessellate; stylet length 41 East. It is just east of the St. Lucie Canal less than 120 um ...... D. profundus (11) and near the center of the Hanson Grant. 6. Lip region roundedl anterior cuti- Diagnosis: Dolichodorus miradvulvus n. sp. cle not tessellate; styler length more resembles D. heterocephalus and D. marylan- than 130 ~m ...... D. silvestris (4) dicus but differs from both in having a long- 7. Excretory pore usually opposite er styler and a more anteriorly located ex- middle of basal bulb ...... D. similis (5) cretory pore. It differs from those two and 7. Excretory pore opposite isthmus ...... 8 all other species of Dolichodorus by having 8. Female tail average between 88- 1) deep grooves in the cuticle on the ven- 104 ~m; tail-spike over 2A of tail tral surface anterior and posterior to the length ...... 9 vulva of adult females, 2) pouches which 8. Female tail average less than 75 #m, appear as sclerotized accessory pieces by tail spike less than % of tail length light microscopy, 3) a constricted area of ...... 0 the stylet shaft just anterior to the knobs, 9. Female tail spike over ~ of tail 4) somewhat angular stylet knobs, and 5) length, bursa extending one tail intersection of lateral field and bursa ap- length beyond tail tip ...... pearing sclerotized in males...... D. kishansinghi (7) 9. Female tail spike not over sA tail KEY TO DOLICHODORUS SPP. length, bursa extending slightly be- 1. Excretory pore anterior to median yond tail tip ...... D. grandaspicatus (12) bulb, usually opposite base of stylet 10. Body length less than 2 mm ...... D. pulvinus (6) ...... D. minor (9) 1. Excretory pore more posterior ...... 2 10. Body length greater than 2 mm .... 11 2. Cuticle anterior and posterior to 11. Stylet length 62-76 #m ...... vulva with deep grooves ...... D. aestuarius (1) ...... D. miradvulvus n. sp. 11. Stylet length 83 t~m or more ...... 12

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FIG. 4. Dolichodorus miradvulvus n. sp. males (A-D = SEM; E, F = LM). A) En face showing angular oral disc, four lobes, and prominent amphids (note secretions). B) Tail with raised lateral field, large dentate bursa, and bifurcate tip. C) Tail with large infolding, dentate bursa. D) Tail with protruding spicules and guber- naculum with rounded tip enclosed by bursa and bifurcate tail tip. E) Tail (ventral view) showing prominent intersection of lateral field and bursa; spicules; gubernaculum; bifurcate tail tip with one portion missing. F) Tail (lateral view) showing prominent intersection (appears sclerotized) of lateral field and bursa and pro- truding spicules. 36 Journal of Nematology, Volume 17, No. 1, January 1985 Dolichodorus miradvulvus n. sp.: Smart, Khuong 37

12. Stylet length 83-92/xm; tail short, with in Kerala, India. Indian Journal of abruptly reduced in diameter, acu- Nematology 1 : 116-127. 7. Jairajpuri, M. S., and S. A. Rahmani. 1979. Dol- minate terminus often spicate ...... ichodorus kishansinghi n. sp. (Nematoda: Dolichodori- ...... D. marylandicus (8) dae). Indian Journal of Nematology 7:183-185. 12. Stylet length 99 #m or more; tail 8. Lewis, S. A., and A. M. Golden. 1981. Descrip- smoothly tapering or irregularly tion and SEM observations of Dolichodorus marylandi- cus n. sp. with a key to species of Dolichodorus. Journal conoid, acute terminus ...... of Nematology 13:128-135...... D. heterocephalus (2) 9. Loof, P. A. A., and R. D. Sharma. 1975. Doli- chodorus minor n. sp. (Nematoda: ) with LITERATURE CITED a key to genus Dolichodorus. Revista Theobroma CE- PEC, Itabuna, Brasil 5:35-41. 1. Chow, F. H., and A. L. Taylor. 1978. Dolicho- 10. Luc, M., and F. E. Caveness. 1963. Dolichodorus dorus aestuarius n. sp. (Nematoda: Dolichodoridae). nigeriensis n. sp. (Nematoda: Dolichodoridae). Pro- Journal of Nematology 10:201-204. ceedings of the Helminthological Society of Wash- 2. Cobb, N. A. 1914. The North American free- ington 30:297-299. living fresh water nematodes. Contributions to a sci- 11. Luc, M. 1960. Dolichodorus profundus n. sp. ence of hematology. Transactions of the American (Nematoda: Tylenchida). Nematologica 5:1-6. Microscopical Society 33:69-134. 12. Robbins, R. T. 1982. Description of Dolicho- 3. Doucet, M. E. 1981. Description de Dolichodorus dorus grandaspicatus n. sp. (Nematoda: Dolichodori- longicaudatus n. sp. et Neodolichodorus leiocephalus n. dae). Journal of Nematology 14:507-511. sp. (Nematoda: Tylenchida). Revue de Nematologie 13. Seinhorst, J. W. 1959. A rapid method for the 4:191-197. transfer of nematodes from fixative to anhydrous 4. Gillespie, W. H., and R. E. Adams. 1962. An glycerine. Nematologica 4:67-69. awl nematode, Dolichodorus silvestris n. sp., from West 14. Smart, G. C.,Jr., and N. B. Khuong. 1984. A Virginia. Nematotogica 8:93-98. new awl nematode inhibits rooting of the aquarium 5. Golden, A. M. 1958. Dolichodorus similis (Doli- plant Anubias nana. Proceedings of the First Inter- chodorinae), a new species of plant nematode. Pro- national Congress of Nematology held in Guelph, On- ceedings of the Helminthological Society of Wash- tario, Canada, 5-10 August 1984 (in press). ington 25:17-20. 15. Stone, A. R., and C. D. Green. 1971. A simple 6. Khan, E., A. R. Seshadri, B. Weischer, and K. method of preparing nematodes for scanning elec- Mathen. 1971. Five new nematode species associated tron microscopy. Nematologica 17:490-491.

FIG. 5. Dolichodorus miradvulvus n. sp. (A-D, F) and D. heterocephalus (E). A) Vulva showing pouches posteriorly and anteriorly. B) Enlargement of a pouch showing either supporting ribs or fixation artifacts. C) Strengthening ridges in walls of vagina. D) Vulval region with deep grooves and pouches, anterior and posterior to vulva. E) Vulval region of D. heterocephalus. Region anterior and posterior to vulva with no pouches and a pattern unlike that of D. miradvulvus. F) Lateral field with three incisures of D. miradvulvus.