Two new mecies of Discocriconernella (Nematoda : biconematidae) from Brazil

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1 Two new mecies of Discocriconernella (Nematoda : biconematidae) from Brazil Nicola VOVLAS and Ravit Datt SHAFMA Istituto di Nematologia Agraria, CNR, Via G. Amendola 16.5/AY Bari, Italy and EMBRAE AKPA Cerrados, Cl , Planaltina, DF, Brazil. SUMMARY Two new species of Discocriconemella collected by the second author in Brazil are described and illustrated. Discocriconemella paraglabrannulata n. sp. has, like D. glabrannulata De Grisse, 1967, a broadly hemispherical tail but it differs from that species in its greater body and stylet length, higher annuli number, presence of spermatheca with sperms and by the only ventrally and dorsally indented head-disc. D. conicaudata n. sp. with bluntly conical post-vulval body portion only resembles D. nzauritiensis (Williams, 1960) De Grisse & Loof, 1965 but differs mainly in stylet length, smaller number of body annuli, and the almost smooth posterior margins of the body annuli. Males were not found in either of the new species. RESUME Deux nouvelles espèces de Discocriconemella (Nematoda : Criconematidae) provenant du Brésil Deuxnouvellesespècesde Discocn conemella, récoltéesparlesecond auteur,sontdécritesetillustrées. Discocriconemella paraglabrannulata n. sp. présente, comme D. glabrannulata De Grisse, 1967, une queue hémisphéroïde, mais s en différencie par la plus grande longueur du corps et du stylet, le nombre plus élevé d anneaux, la présence d une spermathèque emplie de spermatozoïdes, le disque céphalique présentant seulement une indentation ventrale et une indentation dorsale. D. conicaudata n. sp., par sa portion post-vulvaire conique-obtuse, n est proche que de D. mauritiensis (Williams, 1960) De Grisse & Loof, 1965, mais s en sépare par la longueur du stylet, le plus faible nombre d anneaux, et la bordure postérieure presque lisse des anneaux du corps. Aucun mâle appartenant à l une ou l autre espèce n a été observé. During a survey for plant parasitic nematodes in the Distrito Federal, Brazil, carried out in 1987, two undescribed species were found belonging to the genus Discocriconemella De Grisse & Loof, Their morpho-anatomy is described below and shown in drawings, light microscope (LM) and electron stereoscan (SEM) illustrations. Soil samples were collected from a natural cerrado site. The specimens studied were fiied in hot 5 O/O formalin, processed and mounted in glycerine (Seinhorst, 1966). For scanning electron microscope studies Wergin s (1981) methods were used to prepare the specimens which were observed and photographed with a JEOL 50 A Stereoscan at 5 kv of accelerating voltage. Discocriconemella paraglabrannulata n. sp. (Figs 1 A-C; 2; 4 A-C) MEASUREMENTS Fetnale : see Table 1. Revue Ne matol. 12 (3) : (I989) Holotype (female) : L = 450 pm; body diam. = 52 pm; a = 8.6; oesophagus = 92 pm; b = 4.8; tail = 18 pm; c = 25; V = 93 %; stylet = 48 pm; Rst = 14; Rex = 28; Rv = 8; Ran = 6; VL/VB = 0.9; St. O/O L = 10.6; St. O/o oes = 52; head-disc in lateral view = 11.2 Pm. DESCRIPTION Fernales : body curved ventrally when relaxed, cylindrical for most of its length and tapering slightly at both ends. Annuli with posterior margins smooth with rare anastomoses. Head-disc 10 & 0.5 (9-11) pm wide, appearing in en-face view quadrangular, smooth, dorsally and ventrally indented. Inside the head-disc is the oral disc, with small projections on its angles, bearing the 1-like oral aperture and the distinct oval amphidial openings. Stylet robust, with rounded to pointed anteriorly directed knobs 9.2 -I- 0.7 (8-10) pm wide. Oesophagus typical. Excretory pore near the base of the oesophagus. Ovary usually outstretched some- 277

2 N. Vovlas & R. D. Sharma Fig. 1. Light microscope photographs : Discocriconemella paraglabrannulata n. sp. Female. A : Anterior body part; B, C : Posterior body part (lat. and ventral views). Discocriconemella conicaudata n. sp. Female. D : Oesophageal region; E, F : Posterior body part (lat. view). (Scale bars = 20 Pm). 278 Revue Nématol. 12 (3) : (1989)

3 Two new Discocriconemella D H B y.&j Fig. 2. Discocriconemella paraglabrannulata n. sp. Female. A, G : Oesophageal region, lateral view; B, C, H : Posterior body part (lat. view); Dy E : Annuli structures at mid-body; F : Posterior body part (ventral view). Revue Nématol. 12 (3) : (1989) 219

4 N. Voolas & R. D. Sharrna B F Fig. 3. Discocn conemella conicaudata n. sp. Female. A, G : Oesophageal region (lat. view); B, F : Posterior body part (lat. view); C, D : Annuli structure at mid-body; E : Posterior part (ventral view); H : Entire female. 280 Revue Neinatol. (1989) 12 (3):

5 Fig. 4. SEM photomicrographs : Discocriconemella paraglabrannulata n. sp. Female. A, B : Head-disc (face-view and profile); C : Posterior body part (ventral view); Discocriconewda conicaudata n. sp. Female. D : Head-disc; E, F : Posterior body portion. (Scale bars = 5 pd. Revue Nématol. 12 (3): (1989) 281

6 N. Vovlas dt R. D. Shamza times extending anteriorly to stylet knobs. Sperrnatheca spherical, pm in diameter and full of sperms. Vulva open. Tail broadly hemispherical with multi-lobed terminus. Anus distinct positioned at the posterior margin of 56th annulus from terminus. Males : not found. TYPE HABITAT AND LOCALITY Rhizosphere of cerrado (= scrub) vegetation, Distrito Federal, Brazil. TYPE MATERIAL The female holotype and twenty female paratypes have been deposited at Istituto di Nematologia Agraria del Consiglio Nazionale delle Ricerche, Bari, Italy. A slide with two or three females has been sent to each of the following institutions : EMBRAPA, Planaltina, DF, Brazil; Nematol. Dept., Rothamsted Experimental Station, Harpenden, England; Laboratoire des Vers, Muséum natn. Histoire nat., Paris, France; Dept. Nematology, Landbouwhogeschool, Wageningen, the Netherlands; USA Nemathde Collection, Beltsville, Maryland, USA; University of California, Nematode Survey Coll., Davis, California, USA. DIAGNOSIS AND RELATIONSHIPS. Discocriconemella paraglabrannulata n. sp. is distinguished by its broadly hemispherical tail, smooth body annuli, body length pm, stylet pm, total number of body annuli (R = ) and the quadrangular, smooth only dorsally and ventrally indented head disc. Discocriconemella paraglabrannulata n. sp. in having smooth annuli and broadly hemispherical tail resembles D. glabrannulata De Grisse, However D. paraglabrannulata can be distinguished from D. glabrannulata in having a longer body length ( vs pm), higher annuli number (R = vs 83-92), longer stylet (44-49 vs Pm); the quadrangular, smooth only dorsally and ventrally indented head-disc of D. paraglabrannulata differs from the four-lobed head-disc that De Grisse (1967) drew for D. glabrannulata. Unfortunately SEM illustrations of D. glabrannulata are not available for comparison. Discocriconemella conicaudata n. sp. (Figs 1 D-F; 3; 4 D-F) MEASUREMENTS Female : see Table 1. Holotype (female) : L = 260 pm; body diam. = 41 pm; a = 6.3; oesophagus = 81 pm; b = 3.2; tail = 13 pm; c = 20; V = 93 %; stylet = 41 pm; Rst = 16; Rex = 28; RV = 8; Ran = 6; VL/VB = 0.8; L = 16; St. O/O oes = 50; head-disc width = 9 pm. 282 Table 1 Morphometric data of the females of the two new species of Discocriconemella. (Figures : first line = extremes; second line = mean and st. deviation) L (mm) Maximum body diam. (Pm) f 4.2 Oesophageal length (Pm) f 4.4 Excret. pore from ant. end (Pm) f 7.3 a b f 0.3 C zk 2.3 v Y f 0.5 (St) (pm) Stylet f 1.4 St. Y0 L f 0.9 St. YO Oes t 3.0 R f 2.5 Rst f 0.5 Roes f 1.2 Rex f 1.0 Rv k 0.6 Ran f 0.6 VLlvB* VLlSt zk 0.05 Head-discdiam. (lat.view;pm) & 0.5 (Pm) length Tail f 1.9 * Post-vulval body distancelbody width at vulva D. paragla- D. conibrannulata caudata n. sp. n. sp. (n = 16) (n = 21) f f k f f t k t k f t f f t k k zk f & 1.8 Revue Nirnatol. 12 (3) : (1989)

7 - ~ Two new Discocriconemella DESCRIPTION Females : Body moderately curved ventrally when relaxed, cylindroid, tapering at both extremities. Body annuli with posterior margins almost smooth, with rare anastomoses, Head-disc 9.6 _ ( ) pm wide appearing in " en-face " view quadrangular four-lobed, dorsally, ventrally and laterally indented. Amphid apertures large and oval. Stylet robust with rounded to pointed anteriorly directed knobs 8.9 -t 0.7 ( ) pm wide. Oesophagus typically criconematoid. Gonad typical, spermatheca without sperms, vulva open usually situated 7-9 annuli from terminus, on a ventrally enlarged annulus. Anus distinct 2-3 annuli posterior to the vulva. Post-vulval body portion gradually tapering, tail conoid almost straight dorsally and ventrally. Terminus usually with a rounded and lobed terminal annulus. Males : not found. TYPE HABITAT, LOCALITY and distribution of?kp~ MATERIAL as for D. paraglabrannulata. DIAGNOSIS AND RELATIONSHIPS Discocriconemella conicaudata n. sp. is distinguished by its conical post-vulval body portion, stylet length (40-45 p), total number of body annuli (R = ), position of th excretory pore (Rex = 25-28) and smooth posterior margins of body annuli. Discocriconemella conicaudata n. sp. in having conical post-vulval body portion resembles D. mauritiensis Williams, 1960) De Grisse & Loof, 1965, however it differs mainly in having longer stylet (40-45 vs pm), lower annuli number (R = vs ), and anteriorly positioned excretory pore (Rex = vs 42-47). In addition posterior margins of body annuli in D. conicaudata n. sp. are almost smooth whereas they are crenate in D. mauritiensis. AKNOWLEDGEMENT We thank Dr.P.A.A.Loof for his constructive comments regarding some characteristics of the new species. REFERENCES DE GRISSE, A. (1967). Description of fourteen new species of Criconematidae with remarks on different species of this family. Biol. Jaarb. Dodonaea, 35 : DE GRISSE, A. & LOOF, P. A. A. (1965). Revision of the genus Cnconenzoides (Nematoda). Meded. Landbhoogesch. OpzoekStns Gent, 30 : SEINHORST, J. W. (1966). Killing nematodes for taxonomic study with hot 'FA 4 : 1. Nematologica, 12 : 178. WERGIN, W. P. (1981). Scanning electron microscopic techniques and applications for use in nematology. In : Zuckerman, B. M. & Rohde R. A. (Eds). Plant-parasitic Nematodes, Vol. III. New York & London, Academic Press : Accepté pour publication le 17 octobre Revue Nématol. 12 (3) : (