A new Rotylenchulinae : Serzegalonema sorglzi n. gen., n. sp. (Nematoda : ) Gaetano GERMANI*, Michel Luc ** and James G. BALDWIN*** * Laboratoire de Ne’matologie, ORSTOM, B.P. 1386, , Sénégal; ** Muséum national d’Histoire naturelle, Laboratoire des Vers, 61, rue de Buffon, and *** Department of Nematology, University of California, Riverside, Ca 92521, USA.

SUMMARY Description is given of Senegalonema sorghi n. gen., n. sp., parasitic on sorghum, at Patar, . This new genus, close to Rotylenchulus Linford & Oliveira, 1940, differs from it by several characters : more anterior position of the dorsal oesophageal gland orifice ; genital branches outstreched in immature female ; stylet and oesophagus only slightly regressed in males which exhibit terminal caudal alae ; moreover the structure of the lip region, as seen by SEM, appears very specific. Senegalonema n. gen. is considered as constituting, with Rotylenchulus, the subfamily Rotylenchulinae, within the Hoplolaimidae. Relationships between those genera of this family where females are inflated, with the family Heteroderidae (incl. Meloidogyninae) are discussed.

RÉSUMÉ Un nouveau Rotylenchulinae: Senegalonema sorghi n. gen., n. sp. (Nenzatoda: Tylenchida) Senegalonema sorghi n. gen., n. sp., parasite du sorgho à Patar, Sénégal, est décrit et figuré. Proche de Rotylen- chulus Linford & Oliveira, 1940, le nouveau genre en diffère par la position plus antérieure de l’ouverture de la glande oesophagienne dorsale ; des ébauches génitales droiteschez la femelle immature ; une faiblerégression seule- ment du stylet et de l’oesophage et une bourse terminale chez le mâle. La structure de la région labiale, observée au microscope électronique à balayage, apparalt très particulibre. Les auteurs considèrent les Rotylenchulinae comme appartenant aux Hoplolaimidae et discutent les relations entre genres de cette famille où les femelles sont renflées et ceux appartenant aux Heteroderidae (incl. Meloidogyninae).

During a survey of various food crops in Senegal, 1974 and M. chitwoodi (Golden & Jensen,1974). the senior author observed a parasitizing Stone, 1977 wereexamined withSEM for comparison. roots of sorghum, which, at first glance, was thought Fixedspecimens were infiltrated with glycerin and to be a new species of RotylencAulus Linford & Olive- mounted as reported by Sher and Bell (1975). Speci- ria, 1940. Closer examinationindicated thatthe mens were sputter-coated with 20 pm gold-palladium species observed pertains to a new genus, morpholo- and examined with a Jeol35C SEM at 5MV. gicallysimilar to Rotylerzchulus. These taxaare described below as Senegalonema sorghi n. gen., n. sp. Senegalonema n. gen.

Material and methods DIAGNOSIS Tylenchida.Hoplolaimidae. Maturefemale fixed Examination has been made on specimens killed in roots; body entirely annulated,swollen posteriorly; by gentle heat, fixed with FA 4 : 10 and then pro- vulvapostequatorial ; twogenital branches, con- cessed to glycerin by Seinhorst’s (1959) rapidmethod. voluted ; tail short ; phasmids large. Immature fernale Youngfemales, males and juveniles of S. sorghi free in soi1 ; lip region not set-off ; cephalic frame- n. gen., n. sp. were prepared for observations of the worlr conspicuous ; dorsal oesophageal gland orifice lipregion withthe scanning electron microscope less than one half stylet length posterior to base of (SEM).In addition, immature females of Rotyletz- stylet. Oesophagus long, with glands filling pseudo- clzulusreniformis Linford & Oliveria,1940 and coelom, overlapping intestine laterally, or ventrally, Nacobbusdorsalis Thorne & Allen,1944 as well as moreoften laterally. Genital tract immature, juveniles of Meloinemakerotzgense Choi & Geraert, composed of twooutstretched branches. Male free

** Nematologist of ORSTOM.

Revue Nimalol. 7 (1) : 49-56 (1984) 49 G. Germani, M. Luc 6: J.G. Baldwin - in soi1 ; stylet shorter than in female ; oesopliagus the pseudocoelom, short but well expanded laterally. less developed than in female, but not degenerated. Oesophago-intestinaljunction obscure, devoid of Caudalalae shallow, terminal. With SEM, in both conspicuousvalve. Excretory pore at midlevel of maleand immature female, labial area charac- oesophageal glands. Hemizonid and hemizonion not terized by labial disc fused with four dorso-ventrally seen. Vulva postequatorial ; vulva lips not protrud- elongatedtriangular submedial lips ; apex of sub- ing. Two genitalbranches, long convoluted, filling media1lips and trapezoidal lateral lips extend pos- posterior part of the body. Anus situated in depres- terior to region of basal plate ; labial area without sion. Tai1 conical, short (15-22 pm), annulated at its transverseannules. Amphids elongate. Eggs base.Phasmids prominent, large (5 pm diam), embedded in gelatinous matrix. associated with one or more specialized cells. Immature female TYPE ANDONLY SPECIES When heat-relaxed, body ventrally curved, assum- Senegalonemasorghi n. gen., n. sp. ing bracket ta U-shape. Body cylindrical, with slight Relationships of the genus are discussedbelow. tapering at anteriorend as well as tapering beginning a shortdistance from posterior end. Cuticle thin ; Senegalonema sorghi n. gen., n. sp. transverse annulations shallow (annules about1.8 pm, (Fig. 1-3) at mid-body), more pronounced posteriorly including tail. Lateral fields about 6 pm wide (i.e., 1/3 of body MEASUREMENTS diameter, at mid-body),with four lat.eral lines ; outer lines slightly wavy, inner lines straight ; areol- Adult females (n = 7). L = 0.21-0.78 mm ; a = ation of outer bands faint, only present posteriorly 2.6-4.7 ; = 61.5-76.9 ; stylet = 17-23 pm. V includingtail ; lateral field nearlyextends to tail Immature females (n = 45). L = 0.49 mm (0.39- extremity. No deirids.Lip area rounded, flat 0.55) ; a = 24.4 (18.5-29) ; b' = 2.3 (1.9-3.3) ; c = anteriorly,not annulat>ed, continuous with the 16.7 (14-19.5) ; V = 73.9 (70.3-76.5) ; stylet = rest of the body. SEM : labial disc fused with four 25.5 pm (22-28). submedial lips ; submedial lips triangular and very Males (n = 19). L = 0.38 mm (0.35-0.42) ; a = elongate with apex of triangle extending posteriorly 18.4 (15.8-18.9) ; b' = 4.5 (3.7-6.0) ; c = 17.1 (15.4- to level of basal plate ; lateral lips trapezoidal, also 20.7) ; C' = 1.6 (1.3-1.9) T = 59.6 (48.5-74.6) ; extendto level of basalplate ; liparea without stylet = 19.5pm (18-21.5) ; spicules = 27 pm transverseannulation. Amphid openings slit-like. (23-32.5) ; gubernaculum = 11.5 pm (9-13.5). Cephalicsclerotization of mediumdevelopment. Holotype (immaturefemale). L = 0.53 mm ; Anteriorcephalids at level of 1st or 2ndbody a = 24.1 ; b' = 2.9 ; c = 16.4 ; c' = 2.2 ; V = annule ; posteriorcephalids at level of 6th or 7th 8074.272; stylet = 25 pm ; cone = 15 pm. bodyannule. Stylet strong, basal knobs rounded, closely appressed tothe shaft. Dorsaloesophageal DESCRIPTION glandopening at 5-7 pm fromthe base of stylet. Oesophagusprocorpus swollen at anteriorend and Adult female more or less regularlytapering to median bulb. Anterior part of the body irregular, vermiform ; Median bulb oval inprofile, of medium development, posteriorpart. swollen, variously shaped including not sharply set-off from procorpus, or from isthmus. kidney-shaped, or saccate, most often witha constric- Isthmusthick, short, encircled bynerve ring. tion at vulva level which is more pronounced ven- Oesophagealglands considerably developed, filling trally. Cuticle withirregularly rounded annules in almost al1 the pseudocoelom, apparently free within anteriorpart ; posteriorpart entirely annulated, it ; dorsalgland smaller than subventral ones, annules flat, separations weak.Cuticle thin (1.5-2 pm) withposterior part hyaline and with prominent anteriorly,progressively thickened posteriorly (to nucleus ; subventral glands with fine, dense granu- 10-13 pm). Lateral field not seen. Lip area irregularly lation,provided with smaller more obscure nuclei. rounded,often with a circulardepression, butno Oesophago-intestinal junction inconspicuous, rather annulation.Cephalic sclerotization weak. Cephalids anteriorlysituated, without conspicuous valve ; not seen. Stylet weak ; basal knobs rounded, closely overlapping of oesophagealglands laterally and appressed to shaft. Dorsal oesophageal gland opening ventrally,mainly laterally. Intestine without fasci- at 5-8 pm fromstylet base. Oesophagus procorpus culi ; nopost-anal sac. Rectumstraight, short (at long,cylindrical ; medianbulb strong, with well mostone anal diameter long). Excretory pore 93- developed valve ; isthmus short, encircled by nerve 113 Fm fromanterior end. Hemizonid widt.h of ring ; oesophagealglands apparently lying free in two annules, oneor two annules anterior to excretory

50 Revue Nématol. 7 (1) : 49-56 (1984) Senegalonema sorghi n. gen., n. sp.

Fig. 1. Senegalonema sorghi n.gen., n. sp. Young female. B : Oesophageal part ; C : Genital tracts ; D : Anterior part ; F : in toto; H, 1, J : Tails. Males. A : Oesophageal part ; E : Anterior part ; G : Animal in toto; K, L, M : Tails and spicule apparatus. (Each bar represents : F, G : 100 pm ; A, B : 50 Pm, , C, D, E, H-M : 20 Km).

Revue Nématol. Revue 7 (1) : 49-56 (1984) 51 G. Germani, M. Luc h J. G. Baldwin

Fig. 2. Senegalonema sorghi n. gen., n. sp. Adult female. A : Oesophageal part ; B, D : Animal in toto; C : Anterior part ; E : Detail of phasmid ; F : Tail and anus. (Each bar represents : B, D : 250pm ; A : 50 pm ; C, E, F : 20 pm).

pore ; hemizonionwidth of oneannule, seven to Male nine annules posterior to excretory pore. Vulva not protruding, postequatorial ; immature genital tracts General appearanceand anatomy similar to composed of twooutstretched branches, similar in immaturefemale, except for genitalsystem and structure and length (anterior branch = 41-80 pm ; some secondary sexual characters. Cuticular annules posteriorbranch = 32-82 pm).Tail conical, 24- about 1.5 ym, at mid-body. Lateral field similar to 32 pm long ; extremitygenerally rounded, more immature female, 6 pm (5-8.5) wide or 28% (22-37) rarely pointed ; with 9-15 annules (ventrally) which of bodydiameter at mid-body. No deirids.Lip aremore prominent and wider than on body ; area with cephalic sclerotization similar to that of extremity (8-10pm) withoutannules ; cuticle of immature female ; height of liparea 3-5.5 pm, tailvery thiclr at extremity,forming ahyaline diameter at base = 8.5-10 pm ; SEM facepattern portion 15-21 pm long or 5141% of taillength ; as inimmature female. Stylet shorter and weaker outerlines of lateral field reachingnearly ta tail thanin immature femalewith basal knobs more extremity ; inner lines endingslightly anteriorly ; closely appressed toshaft ; knobwidth = 1.5- outer bandsof lateral field areolated on tail aswell as 2 pm ; knobheight = 3-3.5 ym ; cone length = a short distance anterior to anus. Phasmid rounded, 10.5 pm (9.5-12). Dorsal oesophagealgland orifice 1.5 pm diameter,very refringent, positioned in 6 pm (3-8) fromstylet base. Oesophagus similar center of central band of lateral field, situated 1-4 pm to that of immature female, but less developed, posterior to anus. particularly the median bulb ; but oesophagus not

52 Reuue Nématol. 7 (1) : 49-56 (1984) Senegalonema sorghi n. gen., n. sp.

Fig. 3. Senegalonema sorghi 11. gen., n. sp. SEM pictures. A : En face view of immature female. B : En face view of male. C : En face view of second stage juvenile. D : Lateral view of anterior region of second stage juvenile. E : Lateral view of immature female. F : Lateral view of tail region of immature female. (Arrow- head indicates position of phasmid). G : Latero-ventralview of tail region of male. (Arrowhead indicates position of spicule).

Revue Nèmatol. 7 (1) : 49-56 (1984) 53 G. Germani, M. Luc dl- J.G. Baldwin

Paratypes : Two imm. QQ and two $8 deposited in each of the followingnematological collections : Univ.California, Riverside, U.S.A. ; Univ. Cali- fornia,Davis, U.S.A. ; US National Collection, Beltsville,Md., U.S.A. ; RothamstedExperimental Station,Harpenden, U.K. ; Landbouwhogeschool, Wageningen, ; ORSTOM, Dakar, Séné- gal.Remaining type material in ParisMuséum's Collection.

RELATIONSHIPS Senegalonema n.gen. appears morphologically similar to Rolylenchulus withrespect to several characters.Mature females are embedded in roots and swollen posteriorly, immature females are vermi- form, free in soil andwith well-develoged genital primordium ; oesophageal glands are well-developed andoverlap the intestine laterally and slight.ly ventrally ; eggs are embedded in gelatinousa Fig. 4. Drawingillustrating enface pattern of Senegalonemasorghi n. gen. n.sp. in relation to matrix. certainother Tylenchida. A : Basic pattern for Senegalonema n. gen.differs, however, from Tylenchida. A : amphid ; LD : labial disc ; LL : Rotylenchulus by a series of importantcharacters ; lateral lip sector ; SmL : submedial lip sector. B : i) in both immature females and males the lip area Immature female of Senegalonema sorghi n. gen. n. isdistinctive, as shown by SEM(Figs. 3 A-E ; sp. C : Immature female of Rotylenchulus reniformis. 4 B) ; the dorsal oesophageal gland orifice is located D : Immature female of Nacobbusdorsalis. E : " less thanone half styletlength posterior to base Second stage juvenile of Meloinema kerongense. F : Second stage juvenile of Meloinema chitwoodi. of stylet us. more than one half of this length, and oftenone stylet length in Rotylenchulus; ii) in immaturefemales the genitalbranches are out- streched DS. having a double flexure inRotylenchulus; iii) in males the stylet and oesophagus are reduced, degenerat>ed andapparently functional. Excretory butnot degenerate ; caudalalae are terminal us. pore 100 pm (94-109) from anterior end ; hemizonid adanal ; the gubernaculum is provided with titillae. extending width of one or two annules, 2-5 annules The position of both genera with respect t.o family anterior to excretory pore ; hemizonion punctiform, and subfamily present somedifflculties to beassessed. 7-12 annulesposterior toexcretory pore.Genital A good historicalaccount of Rotylenchulus upto tractunique ; spicules slightlycurved, cephalated, 1967, has been given by Dasgupta, Raski and Sher pointed at distal end ; gubernaculum straight, with (1968).The opinion of theseauthors is to follow titillae, not protruding; cloaca marked by prominent Husainand Khan (1967) Who createdwithin the cone. Tai1 conical, pointed, terminus variously shap- Hoplolaimidae Wieser, the subfamily Rotylen- ed,annulation nearly reaching tail extremity ; 1953 hyalinetail terminus 9.5 Fm (6-13.5) long or 42% chulinae elevated to the rank of family by Husain (1976). AndrAssy (1976) also placed Rotylenchulus in (27-51) of taillength. Caudal alae narrow, shallow, Hoplolaimidae, but in the subfamilyRadopholinae terminal.Phasmids on tail, 7.5 Fm (4.5-12.5) pos- Allen & Sher,1967, with Apratylenchoides Sher, terior to cloaca. 1973, Hirschmanniella Luc & Goodey,1963, Praty- lenchoides Winslow, 1958, Radopholus Thorne,1949 TYPE HOST AND LOCALITY and Rotylenchoides Whitehead, 1958 ; al1 these genera, Roots and soil of Sorghum sp., near Patar, Sénégal: except t.he last one, are most generally considered as pertaining tothe familyPratylenchidae Thorne, 1949. On an other hand, Golden and Jensen (1974) TYPE MATERIAL consider Rotylenchulinae as a subfamily of Nacobbi- Holotype : immaturefemale, slide No. 21520, dae Chitwood, 1960 in Het.eroderoidea. deposited atthe Laboratoiredes Vers, Muséum Wedo notaccept these decisionsconcerning nationald'Histoire naturelle, 61 rue de Buffon, families andconsider that Rotylenchulus and Sene- Paris, France. galonema n. gen. share suffkient characteristics with

54 Revue Nématol. 7 (1) : 49-56 (1984) Senegalonema sorghi n. gen., n. sp.

{( classical O Hoplolaimidae (Le. notas defined by of species havenot been available for elucidation AndrBssy,1976) to be included in that family. The of the lip region with SEM. In Meloinema kerongense discovery of Senegalonema n. gen.reinforces this and M. clzitzuoodi submedial lips fuse with the labial opinion by its lesserregression of themale stylet disc andare elongate similar to Senegalonema; and oesophagus, the shorter tail, the terminal caudal however,adjacent lips become fused in Meloinema alae and the outstretched genital female immature and the remainder of the lipregion is not charac- branches. On the other hand, however, the structure terized by longitudinal marlrings. of the labial area Senegalonernain n. gen., as shown by Relationship between Rotylenchulus, Senegalonema SEM, appears unique, as far as it is known, among n.gen., Nacobbus and Meloinema (andperhaps tylenchids. the genus Acontylus Meagher,1967 which shares a Bothgenera considered here suggest a morpho- tendency to the regression of males and swelling of logical linkbetween Hoplolaimidae and Meloido- themature females) haveto be further explored. gyninaeSlrarbilovich, 1959. Anotherstep to Meloi- Specifically, polarity (primitive us. derived) of charac- dogyninae (Heteroderidae)is suggested by the genera ter States must be identified for T7eruius uolvingentis Nacobbus Thorne & Allen,1944 and Meloinema Esser, 1981. Thisonly species of the genus, Choi & Geraert,1974 (= Nacobbodera Golden & placed by the author in the Heteroderidae, subfam. Jensen, 1974). The two species of Nacobbus exhibit Verutinae Esser, 1981, shows in females some simi- (in spiteof the particular shapeof the mature female, larities toRotylenchulinae : anteriorpart of body the presence of only one female genital branch and elongate,posterior partsaccate, vulva submedian, the dorsaloverlapping of the oesophagealglands) remnants of tailin some specimens, anus situated a series of charactersshared with Rotylenchulus in a depression. But the absence of a free immature and/or Senegalonema n. gen. : liparea continuous, femalestage and the morpho-anatomy of males, stylet strong, cephalic sclerotization well developed, whichis close to that of Atalodera Wouts & Sher, bursaterminal ; Nacobbusaberrans (Thorne, 1935) 1971 (Heteroderidae),prohibit classification of the Thorne & Allen,1944 has the same pattern as N. genus Verutus inthe Rotylenchulinae and justify dorsalis wich are quite distinguish fromRofylencAulus. its placement within the Heteroderidae. Mature females exhibita tail. Meloinema also exhibits Atthe moment, we propose,based on abroad characters which frequently occur in Meloidogyninae: spectrum of similarities, Rotylenchulus and Sene- males and juveniles with labial area offset, excretory galonema n. gen. as pertaining to the family Hoplo- porepositioned anteriorly in females (as in Meloi- laimidae and grouped together within the subfamily dogyne Goeldi,1887), maletwisted posteriorly and Rotylenchulinae. devoid of bursa, more posterior positionof the vulva, although the female genital tract has two branches Withinthe cited genera, polarity (primitive us (butin Meloidodera Chitwood, Hannon & Esser, derived) of character States can not be identified for 1955, considered as pertaining to Heteroderidae, the use inphylogenetic analysis including the higher vulva issubmedian). This situation is reffected by taxa to which they pertain. Nevertheless, the overall theplacement of Meloinema, inHeteroderidae- resemblancesbetween supposed “evolved” Hoplo- Meloidogyninae by Choi and Geraert (1974) whereas laimidae(Rotylenchulinae) with supposed “primi- Golden and Jensen (1974)considered it (under the tive” Meloidogyninae (Meloidodera) and other Hete- name Nacobbodera) aspertaining to the subfamily roderidae (Verutus) reinforce thehypothesis of a Nacobboderinae Golden & Jensen, 1974. close common origin of the two families. Thelip region of Senegalonema n. gen. appears to be highly derive,d from the basic hexaradiate lip ACKNOWLEDGEMENTS pattern which occurs throughout many Tylenchida (Baldwin,Luc & Bel!, 1983). It canbe interpreted Thanlrs are dueto A.H. Bell for making SEM photo- as the result of fusion of foursubmedial lips with graphs. the labial disc (without fusion of adjacent submedial lips)and elongation of thesubmedial lips to the REFERENCES base of the lipregion. Thelateral lips also extend posteriorly to the base of the lip region, and trans- ANDRLSSY,1. (1976). Evolufion as a basis for the sysfe- verselipannules are absent. In Rotylenchulus matization of . London, Pitman Publish- reniformis laterallips may extend somewhat pos- ing : 288 p. teriorly, but submediallips are not fused with BALDWIN,J.G., Luc, M. & BELL, A.H. (1983). Contri- the labial disc. Although Dasgupta, Raski and Sher butionto the study of the genus Pratylenchoides (1968) indicate that thelip region is variable among Winslow (Nematoda : Tylenchida). Revue Nématol., species of Rotylenchulus specimens of a large number 6 : 111-125.

Revue Nèmatol. 7 (1) : 49-56 (1984) 55 G. Germani, M. Luc h J.G. Baldwin

CHOI, Y.E. & GERAERT,E. (1974).Description of of the superfamilyHeteroderoidea (Skarbilovich, Meloinema kerongense n.g. n. sp. (Nematoda : Meloi- 1947) Golden, 1971. Geobios, 3 : 9-12. dogynidae)from Korea. Nematologica, 19(1973) : HUSAIN,S.I. & KHAN,A.M. (1967). A new subfamily, 334-341. a new subgenus and six new species of nematodes DASGUPTA,D.R., RASKI, D.J. & SHER,S.A. (1968). A from I'ndia belonging in the superfamily Tylenchoi- revision of the genus Rotylenchulus Linford and dea. Proc. helminth. SOC.Wash., 34 : 175-186. Oliveira, 1940 (Nematoda : Tylenchidae). Proc. SEINHORST,J.W. (1959). A rapidmethod €or the helminth. Soc. Wash., 35 : 169-192. transfer of nematodesfrom fixative toanhydrous glycerin. Nematologica, 4 : 67-69. GOLDEN,A.M. & JENSEN,H.J. (1974). Nacobbodera chitwoodi n. gen., n. sp.(Nacobbidae, Nematoda) SHER,S.A. & BELL, A.H. (1975). Scanning electron on Douglas Fir in Oregon. J. Nematol., 6 : 30-37. micrographs of t.he anterior region of some species of (Tylenchida : Nematoda). J. Nema- HUSAIN,S.I. (1976). Phylogeny and inter-relationships fol., 7 : 69-83.

Accepté pour publication le 25 mars 1983.

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