BULLETIN DE L'INSTlTUT ROYAL DES SCIENCES NATURELLES DE BELGIQCE, BIOLOGIE, 64 : 17-42, 1994 BULLETIN VAN HET KONINKLIJK BELGISCH INSTlTUUT VOOR NATUURWETENSCHAPPEN, BlOLOGIE, 64: 17-42, 1994 Scanning electron microscopy observations on Telotylenchinae SIDDIQI, 1960 (Nemata : Belonolaimidae). 3. The genus Tylenchorhynchus COBB, 1913. by Pierre BAUJARD, Danamou MOUNPORT & Bernard MARTINY Abstract CHENG, 1988; RASHlD & HEYNs, 1990; ZEIDAN & Geraert,1990; LAL & HINEs, 1991; GOMEZ BARCINA et Ten species of the genus Tylenchorhynchus were studied under SEM, al., 1992) reveal great differences, particularly in the Observations showed the great heterogeneity of the genus according head face view, between species of Tylenchorhynchus. to the head pattern and confirmed the absence of validity of some characters at the taxonomic level (number of incisures in the lateral More recently, MOUNPORT et al., (1993) compared the field, presence vs absence of longitudinal ridges, presence vs absence ultrastructure of the cuticle of nine species of the genus of notch on the bursa), Four to five different head patterns can be concluding that it might be composed of several genera recognized, corresponding to the cuticle ultrastructure patterns pre­ which must be redefined on the basis of light and scan­ viously defined. Bitylenchus is considered as a junior synonym of Tylcnchorhvnchus, and B. pratensis and B, serranus are transferred to ning electron microscopy. the genus 'lylenchorhynchus. This work presents the results of observations on ten Keywords: Nemata, Belonolaimidae, Tylenchorhvnchus, morpho­ species belonging to the genus Tylenchorhynchus, some logy, scanning electron microscopy. of them previously described and/or transferred in gene­ ra presently considered as synonyms of Tylenchorhyn­ chus (see FORTUNER & Luc, 1987): Bitylenchus Resume FILIP'EV, 1934, Telotylenchus SIDDIQI, 1960, Dolichor­ hynchus MULK & JAIRAJPURI, 1974, Neodolichorhyn­ Dix espcces du genre Tylenchorhynchus ont ete ctudiccs en microsco­ eh us JAIRAJPURI & HUNT, 1984. Nine of these species pie electronique a balayage. Les observations reverent une here­ were studied by MOUNPORT et al. (1993). rogcneite considerable des structures cephaliques cxternes et confir­ ment labsence de validite de certains caractercs morphologiques au niveau taxonomique (nombre dincisures dans les champs lateraux, presence vs absence de cretes longitudinales, presence vs absence dechancrure sur la bursa). Les structures cephaliques externes Material and methods peuvent etre groupees en quatre acinq types diffcrcnts qui correspon­ dent a ceux definis precedemrnent sur I'ultrastructure de la cuticule. SPECIES STUDIED Bitylcnchus est considere comme un synonyme mineur du genre Tvlenchorhynchus, et les especes B. pratensis et H. scrranus sont Tylenchorhynchus annulatus (CASSIDY, 1930) GOLDE:", 1971. transferees au genre Ty lenchorhynchus. Mots-cle : Nemata, Belonolaimidae, Tylenchorhynchus, morphologie, syn. Tylenchorhvnchus martini FIELDING, 1956. microscopie electronique abalayage. Tylenchorhynchus germanii FORTUNER & Luc, 1987. syn. Dolichorhynchus (Dolichorhynchus) elegans GER­ MANI & Luc, 1984. Tylenchorhynchus elegans (GERMAN! & Luc, 1984) FOR­ Introduction TUNER & Luc, 1987 (nee T. elegans SIDDlQI, 1961). Tylenchorhynchus gladiolatus FORTUNER & AMOUGOU, 1973. syn. Dolichorhynchus (Neodolichorhynchus) gladiolatus Recent studies on the taxonomy of the genus Tylenchor­ (FORTUNER & AMOUGOU, 1973) MULK & SIDDIQI, hynchus (SIDDIQI, 1986, FORTUNER & Luc, 1987) are 1982. principally based on morphological and biometrical Neodolichorhynchus gladiolatus (FORTUNER & characters observed in light microscopy. Of the 130 spe­ A\1oCGou, 1973) JAIRAJPCRI & HC'\'T, 1984. cies listed in the genus Tylenchorhynchus (FORTUNER & Tvlenchorhynchus indicus (SIDDIQI, 1960) FORTU:"ER & Lt.c, Luc, 1987), little is known on their morphology as seen 1987. syn. Telotvlenchus indicus SIDDIQI, 1960. under scanning electron microscopy (SEM). Previous Tylenchorhynchus mashhoodi SIDDIQI & BASIR, 1959. studies (SHER & BELL, 1975; LEWIS & GOLDEN, 1981; Tylenchorhynchus microphasmis LOOF, 1960. VOVLAS & CHAM, 1981; JAIRAJPURI & HUNT, 1984; syn. Dolichorhynchus (Neodolichorhynchus) microphas­ SAtJER, 1985; LOPEZ & SALAZAR, 1987; VOVLAS & mis (Loo!', 1960) MULK & SIDDIQI, 1982. 18 P. BAUJARD, D. MOUNPORT & B. MARTINY Fig. 1 - Tylenchorhynchus mashhoodi females (A-D, C-J) and males (E-F. J-L). A and B. C and D, E and F : respecrively in face and lareral view of {he same specimen; C: vu Ivar region; H-L : rails; A-F : scale bar = J /-Lm; C-L : scale bar = JO /-Lm. Scanning electron microscopy observations on Telotylenchinae 19 ... • Neodo/ichorhynchus microphasmis (LOOF, 1960) JAI­ Table 1 : RAJPURI & HUNT, 1984. Laboratory culture conditions and number of specimens Ty/enchorhynchus su/catus DE GUIRAN, 1967. observed under SEM. syn. Do/ichorhynchus (Neodolichorhynchus) su/catus (de Guiran, 1967) MULK & SIDDIQI, 1982. Neodo/ichorhynchus su/catus (DE GUIRAN, 1967) JAI­ Species Soil Extraction Number RAJPURI & Hunt, 1984. temperature date of specimens Ty/enchorhynchus ventra/is (LOOF, 1963) FORTUNER & Luc, and observed 1987. moisture (females-males) syn. Te/oty/enchus ventra/is LooF, 1963. Ty/enchorhynchus vu/garis UPADHYAY, SWARUP & SETHI, T. annulatus 1972. "KK" population 34°-10 28.02.1986 30 syn. Bity/enchus vu/garis (UPADHYAY, SWARUP & SETHI, % 1972) SIDDIQI, 1986. 11.05.1987 42 Ty/enchorhynchus phaseo/i SETHI & SWARUP, 1968. 21.01.1991 30 syn Do/ichorhynchus (Dolichorhynchus) phaseoli (SETHI "CSS" population 34°-10 % 05.03.1986 30 & SWARUP, 1968) MULK & JAIRAJPURI, 1974. 13.12.1986 30 = Ty/enchorhynchus sp. in MOUNPORT et a/., 1993. 23.01.1991 30 T. germanii 34°-10 % 20.11.1986 22-30 ORIGIN OF SPECIMENS 14.02.1991 30-30 T. gladiolatus 30°-10 % 01.12.1986 29-21 T. annulatus: two populations ongmating from 25.05.1987 26-23 Richard-Toll, Senegal in 1982 ("CSS" population) and 27.03.1990 30-30 from samples taken along the road Kaffrine-Koungheul, T. indicus 34°-10 % 08.12.1986 28-30 Senegal ("KK" population) in 1984 and paratypes of T. T. mashhoodi 34°-10 % 19.03.1991 30-30 martini originating from the Riverside Nematode Col­ T. sulcatus 34°-10 % 24.11.1986 20-20 lection, University of California, U.S.A. 26.03.1991 30-30 T. germanii : topotypes from Patar, Senegal in 1984. 24.01.1992 30-30 T. gladiolatus : Nebe, Senegal in 1986. T. ventralis 34°-10 % 12.12.1986 15- 4 T. indicus : Thienaba, Senegal in 1988. 12.03.1990 30-30 T. mashhoodi : Tara, Niger in 1990. T. vulgaris 30°-10 % 26.05.1988 30 T. microphasmis: The Netherlands (sent by Dr. EC. 24.01.1992 30 ZOON). 13.07.1992 30 T. sulcatus : N'Dindy, Senegal in 1982. T. phaseoli 36°-10 % 25.04.1988 30 T. ventralis : Louga, Senegal in 1982. 10.06.1988 30 T. vulgaris : Agadez region, Niger in 1987. 08.03.1991 30 T. phaseoli : Aogadut region, Niger in 1987. PREPARATION OF SPECIMENS FOR SEM STUDIES Results Except for the paratypes of T. martini and specimens of T. microphasmis, the other species were cultured at HEAD constant soit temperature and soit moisture (Table 1) on Sorghum vulgare L. in the laboratory since the sampling T. mashhoodi (Fig. 1, A-F), the two Senegalese popula­ date, extracted by elutriation (SEINHORST, 1962), killed tions of T. annulatus and T. martini paratypes (Fig. 2, A­ by gentle heating (600 C) during 30 seconds and then I) : head square like in lateral view; cephalic constric­ processed without fixation for SEM as described by tion absent; in front view, head rounded to laterally BAUJARD and PARIS ELLE (1987). Specimens of T. micro­ elongated with six more or less pronounced longitudinal phasmis were obtained in fixative and processed by the depressions, two dorso-ventral and four submedial; same technique. Paratypes of T. martini and sorne speci­ three to four cephalic armuli present; oral aperture a mens of T. indicus and T. ventralis were processed for dorso-ventral slit surrounded by a small rim itself sur­ SEM and photographed by Dr. BELL as described by rounded by six labial sensilla; labial disc not prominent, SHER & BELL (1975). squarish to four lobed, demarcated by an incisure inter­ In order to evaluate a possible variability in the morpho­ rupted by the amphid apertures; first cephalic annulus logical characters, several specimens extracted at diffe­ not differentiated into lip sectors; amphid aperture late­ rent times were studied for each species from laboratory rally situated at the edge of the labial disc, circular cultures (Table 1). (occurrence: 27 % in the "CSS" population and 17 % in the "KK" population) to ovoid, the longer axis being dorso-ventrally orientated (occurrence: 73 % in the 20 P. BAUJARD, D. MOUNPORT & B. MARTINY w• ••' 1 Fig. 2 - Tylenchorhynchus annulatus,females; A-F: "CSS" populO/ion, C-.!, L : paralypes ofT. marlini; K, M : "KK" popu­ lalion. A-I : heads (A and B, C and D, E and F, C and H' respeClively laieraI and in fron! l'iew oflhe same specimen); .!-K: vu/val' region (Ihe while arl'Ow shows Ihe direuion of Ihe anleriol' region); L-M : Iails; A-I : scale har = 1 }.Lm; f. Scanning electron microscopy observations on TeJotylenchinae 21 Fig. 3 - Tylenchorhynchus annulatus. fema/es of the "CSS" population. N and O. Q and p. Rand S: respective/y vu/var region and vu/va of the same specimen (the white arrow shows the direction ofthe anterior region): T-W .' tai/s: N. Q, R-W: sca/e bar = 10 /Lm: O. P, S: sca/e bar = J jLI1J. 22 P. BAUJARD, D. MOUNPORT & B. MARTINY "CSS" population and 83 % in the "KK" population). that