: Rodriguez-M., Bell 141 examined and found to have the vulva as a chodoridae, pp. 103-127. in F. Lamberti, C. E. short transverse slit. Taylor, and J. W. Seinhorst, eds. vectors of plant viruses. Plenum Press, Females of the subgenera of Paratri- London and New York. chodorus can be characterized on the basis 5. RAZJIVIN, A. A. and G. PENTON. 1975. A of vulva shape as follows: Nanidorus with new species of the genus (Nema- a short transverse slit, with toda) from the rhizosphere of the sugar cane in Cuba. Zoo. Zh. 54:1082-1083. (Russian a short longitudinal slit, and Atlantadorus with English abstract) with a pore-like opening. 6. RODRIGUEZ-M., R., S. A. SHER, and M. R. SIDDIQI. 1978. Systematics of the monodel- LITERATURE CITED phic species of Trichodoridae (Nematoda: 1. ALLEN, M. W. 1957. A review of the nematode ) with descriptions of a new genus Trichodorus with descriptions of ten genus and four new species. J. Nematol. 10: new species. Nematologica 2:32-62. 141-152. 2. CLARK, W. C. 1963. A new species of Tri- 7. SHER, S. A., A. H. BELL, and R. RODRIGUEZ- chodorus (Nematoda: Enoplida) from West- M. 1977. The face view of Trichodoridae. J. land, New Zealand. N. Z. J. Sci. 6:414-417. Nematol. 9:254-256. 3. COBB, N. A. 1913. New nematode genera found 8. SIDDIQI, M. R. 1973. Systematics of the inhabiting freshwater and non-brackish soils. genus Trichodorus Cobb, 1913 (Nematoda: J. Wash. Acad. Sci. 3:432-444. ) with descriptions of three new 4. LOOF, P. A. A. 1975. Taxonomy of Tri- species. Nematologica 19:259-278.

Systematics of the Monodelphic Species of Trichodoridae (Nematoda: Diphtherophorina) With Descriptions of a New Genus and Four New Species R. RODRIGUEZ-M., 1 S. A. SHER,2 and M. R. SIDDIQI ~ Abstract: I"o show the relationship of the monodelphic species of Trichodoridae with the nominal taxa, the genus Monotrichodorus is redefined, with the addititm of one new species. The new genus Allotrichodorus is proposed on the basis of new species found in Brazi.1; and one new species is described in the genus Paratrichodorus. Key Words: Taxonomy; Trichodoridae; Monotrichodorus monohystera; M. vangundyi; Allotrichodorus campanullatus; A. guttatus; Paratrichodorus (N O westindicus.

The first monodelphic species of Tri- although it was reinstated in Loof's com- chodorus Cobb, 1913, described from prehensive paper on the taxonomy of Venezuela, was named Trichodorus mono- Trichodoridae (6). Andrassy (2), with hystera Allen, 1957 (1). The female of this abbreviated explanation, proposed the species was distinguished by a single out- genus Monotrichodorus on the basis of T. stretched anterior ovary, lower position of monohystera. The uncertainty regarding the vulva, and two pairs of lateral body the taxonomic position of this group pores near the vulval level (1). Loaf (4) and the incomplete description given by mentioned some discrepancies in Allen's Andrassy provided the impetus for this description for specimens which he col- work oil the monodelphic species of this lected in Venezuela. important plant-parasitic taxon. Siddiqi (8) tentatively excluded T. The specimens used in this study are monohystera from the genus Trichodorus, primarily from the nematode survey col- lection held at the University of California, Riverside and Davis, California, USA. All Received for publication 13 October 1976. observations were made on specimens fixed Z, 2Department of Nematology, University of California, in 5% formalin and permanently mounted Riverside, California 92521. Present Address (Senior Author): Colegio de Postgraduados, Escuela Nacional de in glycerin. Some observations were made Agricultura, Chapingo, Mexico. with SEM following the technique of Sher *Commonwealth Institute of Helminthology, The White House, 103 St. Peter's St., St. Albans, Hefts., England. and Bell (7). 142 Journal of Nematology, Volume 10, No. 2, April 1978 Monotrichodorus Andrassy, 1976 9 ~ 3: L = 0.67-0.90 ram; a = 19-24; b

= 4-5; c --- 70-90; T = 60-68; onchiostyle Diagnosis (Expanded): Trichodoridae. = 43-48 #m; spicules = 51-59 p.m; guber- Cuticle not swollen after fixation. Dorsal naculum = 10-13 btm. esophageal gland nucleus anterior to, and San Salvador 6 9 2 : L = 0.82-0.94 (0.87) the same size as, the posterior subventral mm; a = 18-22 (20); b = 4.5-5.2 (4.8); c = gland nuclei. Esophagus not overlapping anus subterminal; V = 80-83; onchiostyle intestine. = 48-53 t~m. Female: Gonad monodelphic, prodel- Fe'male: Body slightly curved ventrally. phic, with flexure at the oviduct; postvulvar Cuticle not swollen after fixation. Post- uterine sac present. Vagina anteriorly vulvar uterine sac less than one body-width directed, more than one-half body-width, in length. Gonad single, prodelphic, with with strong musculature and prominent ttexure at oviduct. Spermatheca round, cuticularization. Lateral advulvar body usually filled with round sperm. Paired pores present. Vulva a transverse slit at lateral vulvar body pores; right pore slightly about 80% of body length. Single caudal posterior to vulva, left pore less than one pore present. body-width anterior to vulva. Vagina elon- Male: Spicules long and slender, cylin- gated, slanted anteriorly with conspicuous drical, with bristles; a longitudinal septum cuticularization. Vulva a transverse slit. running from the head-shaft junction to Anus subterminal. Caudal pore single, near the distal end, opening terminal; fine terminal. transverse striae present along most of Male: Body slightly curved ventrally. spicule length. Copulatory muscles promi- One ventral cervical papilla immediately nent, elongate to oval. Three ventromedian anterior to excretory pore, absent in one supplements, at least one anterior to specimen. Paired lateral cervical pores retracted spicule, posterior supplement near slightly posterior to excretory pore. Three cloaca. Paired ventrolateral postcloacal ventrornedian supplementary papillae, only papillae present. Single subterminal caudal one within range of retracted spicules. pore. Single ventral cervical papilla anterior Spicules arcuated, cephalated, bearing to excretory pore. bristles. Gubernaculum linear. Caudal pore Type species: Monotrichodorus mono- subterminal. hystera (Allen, 1957)Andrassy, 1976. In addition to paratypes that have been Syn. Trichodorus monohystera Allen, studied and illustrated, this species has been 1957 identified from soil around sugar cane, San Other species: Monotrichodorus van- Salvador; soil around banana, Esquinas, gundyi n. sp. Costa Rica; and soil around Solarium sp. Diagnosis: Monotrichodorus can be and AUstroameria sp., Cordillera Blanca distinguished from Trichodorus, the most (3,900 m), Peru. Only females and juveniles closely related genus, by the anterior posi- were present in the few specimens available tion of the dorsal esophageal gland nucleus, from those localities. the monodelphic females with posterior vulva and anteriorly directed vagina; in the Monotrichodorus vangundyi n. sp. male by the long slender cephalated Fig. 2 spicules, fusion o~ outlet of caudal pores, and prominent elongate to oval copulatory Measurements: Paratypes 20 9 9: L = muscles. 0.65-0.81 (0.72)mm; a = 15.5-22.0 (19.5); b = 3.5-5.8 (4.6); c = anus subterminal; Monotrichodorus monohystera (Allen, V = 82.3-85.6 (83.8); onchiostyle = 48-57 1957) Andrassy, 1976 (53) ~m. Syn. Trichodorus monohystera Allen, Paratypes: 20 d dr: L --- 0.67-0.83 (0.73) 1957 mm; a = 18-24 (22); b = 4.3-5.7 (4.6); c = Fig. 1 60-80 (66.6); T = 57-70 (62.2); onchiostyle Measurements: (After Allen, 1957) = 49-56 (53)~m; spicules = 50-57 (54) 10 9 9: L --- 0.61-0.90 mm; a = 15-23; b = ~tm; gubernaculum = 13-16 (14) t~m. 4.2-4.5; c = anus subterrninal; V = 77-83; Holotype ~: L = 0.78 ram; a = 21.6; onchiostyle = 45-52 t~m. b = 4.9; c = 80; T = 57; onchiostyle = Monodelphic Trichodoridae: Rodriguez-M. et al. 14~

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A 0.08 mm B-I 0.03 mm Monodelphic Trichodoridae: Rodriguez-M. et al. 145 55 /~m; spicule = 53 ~,m; gubernaculum = fled as Monotrichodorus vangundyi were 17/,m. Body slightly curved ventrally, more found near the type locality around citrus abruptly curved posteriorly. Cuticle not and banana, and in native forest soils; in swollen after fixation. Excretory pore at 95 Rio Corutu riverbed soil, Puerto Armuel- ~m (94 ~ 5/~m in paratypes) from anterior les, Panama; and around roots of Ceiba end. Paired lateral cervical pores immedi- pentandra (L.) Gaert, Barro Colorado ately posterior to excretory pore. Ventral Island, Panama. cervical papilla 87 /zm (89.3 ± 4.4 t~m in Diagnosis: Monotrichodorus vangundyi paratypes) fi'om anterior end. Onchiostyle n. sp. can be recognized by the position of tip 25 ~m. Collar 30 ,~m from anterior end. male supplementary papillae. M. mono- Three ventromedian supplementary papil- hystera has only the posterior supplement lae, 55, 36, and 9 ~m from cloaca. Spicules within the range of the retracted spicules, conspicuously cephalated, slender, slightly whereas M. vangundyi has the middle and curved ventrally; protruding setae evident posterior supplements within spicular along the proximal two-thirds of protracted range. Females of M. vangundyi differ by spicules, distal third smooth. Gubernaculum position of lateral cervical pores. almost linear. dllotype Q: L = 0.76 ram; a = 20; b = 4.3; V = 86; onchiostyle = 55 /~m. Body ,'lllotrichodorus n. gen. slightly curved ventrally. Cuticle, esophagus, Diagnosis: Trichodoridae. Cuticle swol- and excretory pore as in male. Paired lateral len after fixation. Dorsal esophageal gland cervical pores immediately behind amphid nucleus the same size as subventral gland openings (Fig. 2-E). Gonad single, with nuclei and located anterior to them. In- flexure at oviduct; uterus elongated, di- testine extending anteriorly into esophageal rected anteriorly. Vaginal cnticularization region dorsally and laterally. conspicuous, rodlike. Vulva a large trans- Female: Gonad monodeIphic, prodel- verse slit. Postvulvar uterine sac about one phic, with flexure at oviduct. V = body-width long. Paired lateral body pores approximately 85%. Vagina more than within one vulvar-body-width anterior to half body-width in length, with conspicuous vulva level. Anus and caudal pore sub- musculature and ventral cuticularization. terminal. Spermatheca conspicuous. Postvulvar uter- Holotype: Male collected by S. D. Van ine sac present. Anus subterminal and Gundy; September 4, 1975. Catalogue No. caudal pores almost terminal. Vulva a 21, UCR Nematode Survey Collection, transverse slit. Riverside, California, USA. Male: Caudal alae present. Lateral body Allotype: Female, same data as holotype. pores present. Ventral cervical papilla, if Catalogue No. 22. present, anterior to excretory pore. Spicules Paratypes: 55 ~ ~,, 67 Q ~, 11 jj, same transversely striated, elongate, slender, tubi- data as holotype, distributed as follows: form, with bristles; capitular extension hav- 36 8 8, 43 Q Q, 8 j j, Department of Nema- ing a dorsal groove or depression leading tology, University of California, Riverside, into proximal opening of spicule; lumen California; 8 ~, ~, 13 9 ~, 1 j, Common- of spicule continuous with that of capitular weahh Institute of Heh-ninthology, St. extension (Fig. 3-G); longitudinal septa-like Albans, England; II 88, I1 99, 2 jj, thickening present mainly in distal half of Landbouwhogeschool, Wageningen, The spicule. Gubernaculum not prominent. Netherlands. Three ventromedian supplementary papil- Type habitat and locality: Soil around lae within range of retracted spicules. Large roots of oil palm (Elaeis guineensis), Santa paired lateroventral postcloacal papillae Gurtrudis Ranch, southeast of Rosa Zarate, present. Tail short with paired subterminal Ecuador. Additional specimens also identi- to terminal caudal pores.

////1" \\\\\ FIG. 2-(A-I). Monolrichodorus vangundyi n. sp. A) Female lateral view. /3) Female esophageal region. C) Male esophageal region (Holotype). D) Female posterior region, ventral view. E) Female anterior lateral body pore. F) Vagina and related structures. G) Male tail ventral view (Paratype). H) Male posterior region (Holotype). I) l'rotruding spicule (Paratype). 146 Journal o] Nematology, Volume 10, No. 2, April 1978 Type species: A llotrichodorus campanul- and 5 t~m from cloaca, all within range of latus n. sp. retracted spicules. Caudal alae inconspicu- Other species: A. guttatus n. sp. ous in lateral view. Tail short, bluntly Diagnosis: AUotrichodorus can be dis- rounded. Caudal pores subterminal. tinguished from the most closely related Allotype 2: L - 0.75 ram; a = 12; b -- taxon, Paratrichodorus (AtIantadorus) Sid- 4.4; onchiostyle = 58 ~m. Body slightly diqi, 1973, by the single ovary, posterior curved ventrally. Onchiostyle tip 30 tzm position of the vulva (V = 85%), promi- long. Collar 25 /~m from anterior end. nent wginal cuticularization, and in the Esophagus and nuclei as in male. Ovary male by spicule shape and the presence of single, flexed. Spermatheca well developed, three ventromedian supplementary papillae 40 /znl long, and 400 ~m fi'om vulva, filled located within range of retracted spicules. with small round sperm. Vagina more than The generic name is derived from the one-half body-width; vaginal cuticulariza- Greek word Allo, meaning other, or differ- tion conspicuous, appearing as two small ent, and retains the name Trichodorus, bells in lateral view (Fig. 3-E); vulva a thus being masculine in gender. transverse slit (Fig. 3-F). Postvulvar uterine sac about one body-width long, may contain A Uotrichodorus campanullatus n. sp. a few sperm. Lateral body pores absent. Fig. 3 Tail hemispheric, anus subterminal, caudal pores almost terminal. Measurements: Paratypes 10 9 9: L = HoIotype: Male collected by R. D. 0.63-0.68 (0.67)mm; a = 12-20 (15); b = Sharma, 1973; Catalogue No. 23, U.C.R. 4.0-5.3 (4.5); c = anus subterminal; V = Nematode Survey Collection, Riverside, 83.3-86.4 (84.6); onchiostyle = 46-55 (52.4) California, USA. /~m. Allotype: Female, same data as holotype. Paratypes 10 ~ ~: L = 0.54-0.69 (0.62) Catalogue No. 24. ram; a = 11-20 (15.5); b = 3.6-5.5 (4.5); Paratypes: I0 ~ $, 10 2 2, 15 jj, same c = 60-100 (76); onchiostyle = 45-57 (50.3) data as holotype, distributed as follows: ~tm; spicules = 46-59 (52) ttm; guber- 8 ~, 8 99, I0 jj, Department of Nema- naculum = 14-17 (14.7)~m. tology, University of California, Riverside, Holotype ~: L = 0.69mm; a = 16; b California; 2 ~ ~, 2 9 2, 5 j j, Common- = 4.4; c = 98; T = 69; onchiostyle = 53 wealth Institute of Helminthology, St. tzm; spicules = 58 /zm; gubernaculum = Albans, England. 16 /~m. Body slightly curved ventrally. Type habitat and locality: Soil around Cuticle swollen when fixed. Posterior labial roots of cocoa (Theobroma cocao), Cascata, papillae inconspicuous. Collar 25 tan from Alcobaca, Brazil. Additional specimens also anterior end. Onchiostyle tip 25 /~m long, identified as A. campanullatus have been basal portion slender. Nerve ring 12 /~m examined from cocoa and coffee soils, posterior to onchiostyle. Dorsal esophageal Itabuna, Bahia, Brazil. gland nucleus anterior to posterior sub- Diagnosis: This species can be recog- ventral gland nuclei. Excretory pore 90 ~tm nized by a ventral cervical papilla anterior from anterior end. Ventral cervical papilla to the excretory pore, onchiostyle length, 9 ttm anterior to excretory pore. Paired spicule shape, and campanulate vaginal lateral cervical pores posterior to onchio- cuticularization. The species name is de- style base. Testis elongated, ending 42 /~m rived from the Latin campanulla, meaning from esophagus base. Spicules slender, bell. arcuate, slightly swollen at distal end, with bristles; capitular extension 16 /~m A llotrichodorus guttatus n. sp. long, with dorsal groove or depression. Fig. 4 Gubernaculum not prominent. Three ven- tromedian supplementary papillae, 60, 30, Measurements: Paratypes 5 2 2: L =

"k\\\\ ///# FIG. 3-(A-G). Allotrichodorus campanullatus n. sp. A) Female. B) Male (Holotype). C) Male anterior region, ventral view (Paratype). D) Male posterior region, ventral view (Paratype). E) Vagina and related structures. F) Vulva ventral view. G) Male posterior region (Holotype). Monodelphic Trichodoridae: Rodriguez-M. et al. 147

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FIG. 4-(A-D). Allotrichodorus guttatus n. sp. A) Female anterior region. B) Male anterior region (Holo- type). C) Female posterior region. D) Male posterior region (Holotype). Monodelphic Trichodoridae: Rodriguez-M. et al. 149 0.65-0.72 (0.69) ram; a = 12-15 (13); b = as holotype, distributed as follows: 2 ~ 6, 4.1-5.2 (4.8); c = anus subterminal; V = 3 2 9, 10 jj, at Department of Nematology, 84-88 (86); onchiostyle = 68-71 (69) t~m. University of California, Riverside, Cali- Paratypes 4 8 6: L = 0.67-0.74 (0.71) fornia; 2 $~, 2 99, 3 j j, at Common- ram; a = 12-16 (14); b = 4.3-5.3 (5); c = wealth Institute of Helminthology, St. 60-81 (71); T = 58-74 (64); onchiostyle = Albans, England. 65-72 (70) /~m; spicules = 65-76 (70) ~m; Type habitat and locality: Soil around gubernaculum = 14-18 (16)~m. cocoa (Theobroma cacao), San Francisco, Holotype 6: L = 0.68 mm; a',= 13; b Porto Seguro, Brazil. = 4.3; c = 57; T = 58; onchiostyle = 67 Diagnosis: This species can be recog- vm; spicules = 76 t~m; gubernaculum = nized by absence of ventral cervical papilla, 15 vm. Body almost straight except for onchiostyle length, characteristic spicules, slight ventral curve of the caudal region. single ovary, and drop-shaped vaginal Cuticle swells moderately after fixation. Lip cuticularization. region hemispheric, separated from body by small constriction. Paired lateral cervical Paratrichodorus (Nanidorus) pores slightly posterior to nerve ring. Ven- westindicus n. sp. tral cervical papilla absent. Onchiostyle tip Fig. 5 33 /~nl long. Collar 30 tLm from anterior Measurements: Paratypes 36 9 9: L --- end. Excretory pore 97 ~m from anterior 0.40-0.50 (0.46)mm; a = 17-25 (22); b end, its duct ending in reniform ceil. 3.8-5.4 (4.6); c -- 52-90 (72); V = 60-65 Slender portion of esophagus short, en- (64.7); onchiostyle -- 32-37 (34.5) t~m. larged portion compressed dorsoventrally HoIotype 9: L = 0.46 mm; a = 23; b by intestine. Dorsal esophageal gland nu- 4.5; c = 86; V = 64; onchiostyle = 34 cleus anterior to and same size as posterior t~m. Body slightly curved ventrally. Cuticle subventral gland nuclei. Testis single, with moderately swollen when fixed; subcuticle large round sperm. Spicules slender, elon- with coarse striations. Lip region rounded; gated, cylindrical, with transverse striations; amphid aperture small, at level of post- capitular extension 15 t~m long. Guber- labial papillae. No lateral, ventral, or naculum linear, inconspicuous. Three caudal pores observed. Excretory pore 98 ventromedian supplementary papillae, 5-10 t~m from anterior end. Esophagus truncate, /zm, 19-23 ~tm, and 40-70 t~m from cloaca apparently overlapping intestine lateroven- (ranges from paratypes). Paired sublateral trally. Nucleus of dorsal esophageal gland postcloacal papillae prominent. Tail larger than nuclei of posterior subventral rounded with nearly terminal caudal pores. glands, located near beginning of esophagus Caudal alae inconspicuous in lateral view. enlargement. Posterior subventral gland Allotype ~ : L --- 0.65 ram; a = 15; b = nuclei paired, near esophageal intestinal 4.1; V = 88; onchiostyle = 64 t~m. Body ]unction. Vulva inconspicuous, a transverse slightly curved ventrally in posterior region. slit 1.5-2.0 #m long; vagina inconspicuous, Gonad monodelphic, prodelphic, with less than half body-width, cuticularization flexure; short postvulvar uterine sac. Vagina appearing as two small rectangular pieces. and related structures prominent. Vagina Gonad monodelphic, prodelphic, with more than half body-width, cuticularization flexure; postvulvar uterine sac 23 ~m long. appearing as two rather unequal drops in Spermatheca with small cuneate sperm. lateral view (Fig. 4-C). Vulva a wide trans- Tail conoid, with subdigitate to obtusely versal slit. No lateral body pores observed. rounded terminus, arched dorsally at anal Anus and caudal pores terminal. Tail level. terminus as illustrated (Fig. 4-C). Male: Not found. Holotype: Male collected by R. D. Holotype: Catalogue No. 27. Nematode Sharma, 1973; Catalogue No. 25, U.C.R. Survey Collection, Department of Nema- Nematode Survey Collection, Riverside, tology, University of California, Riverside, California. California, USA. Collected by N. D. Singh; Allotype: Female, same data as holotype. University of West Indies, Trinidad. Catalogue No. 26. Paratypes: Same data as holotype. 28 2 Paratypes: 4 ~ ~, 5 9 9, 13 jj, same data at Nematology Department, University of 150 Journal of Nematology, Volume 10, No. 2, April 1978

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FIG. 5-(A-E). Paratrichodorus (Nanidorus) westindicus n. sp. A) Female anterior region. B) Female an- terior region, ventral view. C) Female gonad, lateral view. D) Female posterior region, lateral view. E) Vulva ventral view. All drawings from holotype. Monodelphic Trichodoridae: Rodriguez-M. et al. 151 California, Riverside, California; 8 9 9 at nuclei. Arrangement of esophageal nuclei Commonwealth Institute of Helminthology, appears constant, and has been used to St. Albans, England. separate Dorylaimids at higher taxonomic Type habitat and locality: Soil around levels (5). roots of cocoa (Theobroma cacao), at Trin- Trichodorids normally have two caudal idad, West Indies. Additional specimens pores; Monotrichodorus is unique in hav- were also identified from soil around roots ing only one. The one-ovaried condition of of sugar cane, same locality. females and the fusion of caudal pores Diagnosis: P. (N.) westindicus is recog- indicate a different line of evolution of nized by the single ovary and posterior trichodorids, therefore substantiating the position of vulva (60-65%), its relatively erection of a new genus to show phylo- long onchiostyle, and typical tail, which genetic relationships among this group of arches dorsally at anal level. . Allotrichodorus differs from Monotri- DISCUSSION chodorus because of the swollen condition Monodelphic are seen in of the cuticle and presence of caudal alae, many groups and are considered to have though those same characters show a close been derived from didelphic forms. One- similarity to Paratrichodorus. Allotri- ovaried forms are the usual condition in chodorus is similar to the subgenus some large taxa (Aphelenchina, Criconem- Atlantadorus (8) in that both have paired atoidea, etc.). In some groups, such loss of lateral cervical pores at the level of the an ovary is the single character separating onchiostyle base and large paired post- genera. This situation is prevalent in cloacal papillae; but it differs by the distinct Tylenchina, where monodelphic and didel- spicule shape and presence of a capitular phic species are placed in separate genera extension which is unique. Females of (e.g., this is the only character known to AUotrichodorus are also unique in having distinguish Helicotylenchus Steiner, 1945, the vagina longer than a vulvar body-width from Rotylenchoides Whitehead, 1958; with large cuticularization, and with the and Radopholus Thorne, 1949, from vulva appearing as a large transverse Radopholoides de Guiran, 1962). slit. Thus this group appears to form a In Dorylaimida, monodelphic and line of evolution different from that of didelphic species are often in the same Trichodorus, Paratrichodorus, or Monotri- genus. In Xiphinema Cobb, 1913, most chodorus and is proposed as the new genus species are didelphic, although in some the A llotrichodorus. anterior gonad appears in several stages of Paratrichodorus (Nanidorus) westindicus regression. This morphological character n. sp., is tentatively described within the has been used in part to divide the genus subgenus Nanidorus. The males of this into subgenera (3). species, when found, should substantiate In monodelphic trichodorids, as in this placement. Tylenchina, the posterior gonad is lost, re- The finding of these new forms justifies sulting in a posterior shift of the vulva. a review of tile entire systematics of Tri- Both species of Monotrichodorus seem chodoridae. morphologically similar to Trichodorus because of the absence of caudal alae, LITERATURE CITED unswollen condition of cuticle, similar 1. ALLEN, M. W. 1957. A review of the nematode arrangement of male copulatory muscles, genus Trichodorus with descriptions of ten and shape of the esophagus. new species. Nematologica 2:32-62. An important difference between Tri- 2. ANDRASSY, I. 1976. Evolution as a basis for the systematization of nematodes. Pitman chodorus and Monotrichodorus is the Publishing Ltd., London (U.K.), San Fran- arrangement of the esophageal gland nuclei. cisco, and Melbourne. 288 pp. In Monotrichodorus the dorsal gland nu- 3. COHN, E., and S. A. SHER. 1972. A contribu- cleus is well anterior to the subventral tion to the taxonomy of the genus Xiph/,nema, gland nuclei, whereas in Trichodorus the Cobb, 1913. J. Nematol. 4:36-65. 4. LOOF, P.A.A. 1964. Free-living and plant- dorsal esophageal gland nucleus lies at the parasitic nematodes from Venezuela. Nema- same level as the posterior subventral gland tologica 10:201-300. 152 Journal of Nematology, Volume 10, No. 2, April 1978

5. LOOF, P. A. A., and A. COOMANS. 1970. On Press, London and New York. the development and location of the esopha- 7. SHER, S. A., and A. H. BELL. 1975. Scanning geal gland nuclei in the Dorylaimida. Proc. electron micrographs of the anterior region IX. Int. Nero. Symposium, held at Warsaw of some species of Tylenchoidea (Tylenchida: in 1969/1970. Nematoda). J. Nematol. 7:69-83. 6. LOOF, P. A. A. 1975. Taxonomy of Tri- 8. SIDDIQI, M. R. 1973. Systematics of the genus chodoridae, pages 103-127. in F. Lamberli, Trichodortts, Cobb, 1913: (Nematoda: Dory- C. E. Taylor, and J. W. Seinhorst, eds. laimida) with descriptions of three new Nematode vectors of plant virttses. Plenum species. Nematologica 19:259-278.

Intraspecific Morphological Variation Among Populations of Pratylenchus brachyurus and P. coffeae ~ A. C. TAR JAN and J. J. FREDERICK2 Abstract: Three populations of Pratylenchus coffeae and two of P. brachyurus, each originating from a single female, were maintained on Citrus spp. or Solanum nigrum L. for several years under greenhouse conditions. Nematodes were extracted from roots, and adult female specimens were killed, fixed, and mounted in glycerine for microscopic study. Variables measured were distance between vulva and anus and lengths of the stylet, posterior uterine sac, and tail. The mean data and coefficients of variability suggest that styler length had the least variability, and length of posterior uterine sac the most. When males and distinct spermathecae are not evident in P. coffeae populations, the species can he distinguished from P. brachyurus by a shorter mean stylet length, longer mean posterior uterine sac length, and much longer distance between the vulva and anus. Key Words: taxonomy, morphometrics, variation, intraspecific variation.

The problem of intraspecific variability spermatozoa. Pratylenchus brachyurus males among plant-parasitic nematodes is well are extremely rare and spermathecae are known and has been adequately docu- empty and usually indistinct. Essentially, mented (3, 5, 11, 12, 14, 15). The those are the characters differentiating the nomenclatural literature abounds with two species in the keys to Pratylenchus by synonymies of taxa which were once con- Loof (6) and Corbett (4). Loof further sidered discrete species but later found to designated P. colfeae as having a broadly be conspecific. Such confusion results, in rounded or indented tail tip, as did Corbett, most cases, from the variability exhibited and P. brachyurus as having an angular lip by a discrete species as affected by food, region. Sher and Allen (10) used only the environment, and other factors. criterion of angular lateral margin of lips Tile species of Pratylenchus most fre- for P. brachyurus and rounded for P. coffeae quently found infecting citrus roots in in their key, although, in the species de- Florida is P. brachyurus (Godfrey, 1929) scriptions, they further differentiated the Filipjev ~: Schuurmans Stekhoven, 1941. two by vulva position, presence of males Pratylenchus coffeae (Zimmermann, 1898) and spermathecae, and tapering tail shape Filipjev 8: Schuurmans Stekhoven, 1941 is (for P. coffeae). Van den Berg (1) referred encountered also, though to a much lesser to the tail terminus of P. brachyurus as extent (13). Both species have been found being bluntly rounded, and that of P. pathogenic to citrus (2, 8), although ~. coffeae as broadly rounded. A detailed study brachyurus was later deemed a weak patho- of the morphology and morphometrics of gen (7). Pratylenchus coffeae populations six Pratylenchus species, including the usually have numerous males and females aforementioned two species, was made by with distinct spermathecae filled with Rom~in and Hirschmann (9). They con- cluded that the shape of the tail termini of Received for publication 6 September 1977. P. brachyurus and P. coffeae showed only 1 Florida Agricultural Experiment Stations Journal Series No. 694. slight variation but admitted that consider- 2Professor and Nematologist I, respectively, University of ably more variability might exist within Florida, IFAS, Agricultural Research and Education Center, P. O. Box 1088, Lake Alfred, Florida 33850. different "natural" populations (not experi-