TWO NEW SPECIES

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TWO NEW SPECIES

OF NIPPOSTRONGYLINAE (NEMATODA: TRICHOSTRONGYLINA: HELIGMONELLIDAE) FROM THE GREY LEAF-EARED MOUSE GRAOMYS GRISEOFLAVUS (SIGMODONTINAE)

IN ARGENTINA

DIGIANI M.C.* & DURETTE-DESSET M.C.*

Summary:

Two new species of Nippostrongylinae, Hassalstrongylus puntanus n. sp., and Stilestrongylus franciscanus n. sp. are described from the intestine of the grey leaf-eared mouse Graomys griseoflavus (Waterhouse, 1 837) (Sigmodontinae) from the Province of San Luis, Argentina. Hossalstrongylus puntanus n. sp. is distinguished from the most closely related species H. dollfusi (Diaz-Ungria, 1963), a parasite of Mus musculus from Venezuela by longer rays 2, shorter rays 4 , proximal half of the dorsal ray non-enlarged and a non-retractile female tail. Stilestrongylus franciscanus n. sp. is distinguished from the most closely related species S . flavescens Sutton & Durette-Desset, 1 9 9 1 , a parasite of Oryzomys flavescens from Argentina, by rays 2 and 3 diverging separately from common trunk of rays 2 to 6 , and by right ray 3 arising from this trunk more distally than ray 6 . Stilestrongylus azarai Durette-Desset & Sutton, 1 9 8 5 , a parasite of Akodon azarae from Buenos Aires, Argentina, was also found parasitizing G. griseoflavus, representing new host and locality records. Some additional morphological data for this species are also provided.

K E Y W O R D S : Hassalstrongylus puntanus n. sp., Stilestrongylus franciscanus n, sp., Stilestrongylus azarai Durette-Desset & Sutton, 1 9 8 5 , Trichostrongylina, Nippostrongylinae, Graomys griseoflavus, Sigmodontinae, Argentina.

Résumé : DEUX NOUVELLES ESPÈCES DE NIPPOSTRONGYLINAE (NEMATODA: TRICHOSTRONGYLINA: HELIGMONELLIDAE) PARASITES DE GRAOMYS GRISEOFLAVUS (SIGMODONTINAE) EN ARGENTINE

Deux nouvelles espèces de Nippostrongylinae, Hassalstrongylus puntanus n. sp., et Stilestrongylus franciscanus n. sp., sont décrites chez Graomys griseoflavus (Waterhouse, 1 8 3 7 ) (Sigmodontinae), dans la province de San Luis, Argentine. Hassalstrongylus puntanus n. sp. se différencie de l'espèce la plus proche H. dollfusi (Diaz-Ungria, 1963!, parasite de Mus musculus du Vénézuela, par les caractères suivants : des côtes 2 plus longues, des côtes 4 plus courtes, côte dorsale non élargie dans sa partie proximale et queue de la femelle non rétractile. Stilestrongylus franciscanus n. sp. se différencie de l'espèce la plus proche S. flavescens Sutton & Durette-Desset, 1991, parasite d'Oryzomys flavescens en Argentine, par des côtes 2 et 3 droites fortement séparées à leur base, et par la naissance de la côte 3 droite après celle de la côte 6 sur le tronc commun aux côtes 2 à 6.

Stilestrongylus azarai Durette-Desset & Sutton, 1985, parasite d Akodon azarae dans la province de Buenos Aires, Argentine, a été retrouvée chez G. griseoflavus qui répresente un nouvel hôte pour cette espèce. Quelques compléments morphologiques sont ajoutés à la description de cette espèce.

MOTS CLES : Hassalstrongylus puntanus n. sp., Stilestrongylus franciscanus n. sp., Stilestrongylus azarai Durette-Desset & Sutton, / 9 8 5 , Trichostrongylina, Nippostrongylinae, Graomys griseoflavus, Sigmodontinae, Argentine.

INTRODUCTION

T

his p a p e r is part o f a major study o n the Nippo- s t r o n g y l i n a e p a r a s i t e s o f N e o t r o p i c a l S i g m o - d o n t i n e rodents. In t w o previous articles, t w o n e w g e n e r a and four n e w s p e c i e s have b e e n described from Scapteromys aquaticus T h o m a s and Oxymycterus

rufus ( F i s c h e r ) from the p r o v i n c e o f B u e n o s Aires ( A r g e n t i n a ) (Digiani et al, 2 0 0 3 , Digiani & Durette- D e s s e t , 2 0 0 3 ) . T h e present p a p e r c o n c e r n s the tri- c h o s t r o n g y l e s parasitic in t h e grey leaf-eared m o u s e

* L a b o r a t o i r e d e B i o l o g i e Parasitaire, P r o t i s t o l o g i e et H e l m i n t h o l o g i e , et CNRS F R 6 3 . M u s é u m N a t i o n a l d ' H i s t o i r e N a t u r e l l e . 6 1 . r u e d e B u f f o n . 7 5 2 3 1 P a r i s C e d e x 0 5 . F r a n c e .

C o r r e s p o n d e n c e : D r M . C . D u r e t t e - D e s s e t .

T e l . : 3 3 ( 0 ) 1 4 0 7 9 3 5 0 9 - F a x : 3 3 ( 0 ) 1 4 0 7 9 3 4 9 9 . E-mail: m c d d @ m n h n . f r

Graomys griseoflavus ( W a t e r h o u s e , 1 8 3 7 ) from t h e p r o v i n c e o f S a n Luis ( A r g e n t i n a ) . T r i c h o s t r o n g y l i d n e m a t o d e s w e r e hitherto u n k n o w n from this host.

T h e only k n o w n report o f parasitic helminths from G.

griseoflavus are t h o s e o f Enterobius yagoi Sutton, 1 9 7 9 (Oxyurida, O x y u r o i d e a ) a n d Pterygodermatites (Pau- cipectines) massoiai (Sutton, 1 9 7 9 ) (Spirurida, Rictula- r i o i d e a ) from the p r o v i n c e o f M e n d o z a (Sutton, 1 9 7 9 , 1 9 8 4 ) ; and o f Mastopborus muris ( G m e l i n , 1 7 9 0 ) (Spi- ruroidea, Spirurida), from a single host in the p r o v i n c e o f La P a m p a (Rojas, pers. c o m m . ) , b o t h from Argen- tina. During this study, t w o n e w s p e c i e s o f Nippos- trongylinae b e l o n g i n g to the g e n e r a Hassalstrongylus Durette-Desset, 1971 and Stilestrongylus Freitas, Lent

& Almeida, 1 9 3 7 are d e s c r i b e d . S o m e additional mor- p h o l o g i c a l d a t a c o n c e r n i n g Stilestrongylus azarai Durette-Desset & Sutton, 1 9 8 5 , a parasite o f Akodon azarae from t h e p r o v i n c e o f B u e n o s Aires, found in G. griseoflavus, are also provided.

P a r a s i t e , 2 0 0 3 . 10. 2 1 - 2 9

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Article available athttp://www.parasite-journal.orgorhttp://dx.doi.org/10.1051/parasite/2003101p21

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D I G I A N I M . C . & D U R E T T E - D E S S E T M . C .

MATERIALS AND METHODS

R

odents w e r e captured from April to May 1990 in two different localities o f the Province o f San Luis, Central West Argentina. T h e b o d i e s w e r e fixed in 10 % formalin and preserved in 7 0 ° ethanol, and w e r e provided b y the Instituto Miguel Lillo (San Miguel d e T u c u m á n , Argentina) in the frame o f an agreement with the División Zoología Invertebrados o f the M u s e o d e La Plata (La Plata, Argentina), for helminthological study. T h e small intestines w e r e o p e n e d a n d the n e m a t o d e s r e c o v e r e d a n d s t o r e d in 7 0 ° e t h a n o l . T h e s y n l o p h e w a s studied following the m e t h o d o f Durette-Desset ( 1 9 8 5 ) and the n o m e n c l a ture used for the study o f the caudal bursa is that o f Durette-Desset & Chabaud ( 1 9 8 1 ) . T h e n o m e n c l a t u r e for parasites used a b o v e the family group is that o f Durette-Desset & Chabaud ( 1 9 9 3 ) and the n o m e n c l a ture o f the hosts follows Musser & Carleton ( 1 9 9 3 ) . Measurements are given in micrometres, e x c e p t w h e r e stated otherwise. T y p e and v o u c h e r s p e c i m e n s are deposited in the Helminthological Collections o f the M u s e o d e La Plata (CHMLP) and o f the M u s é u m National d'Histoire Naturelle, Paris (MNHN).

DESCRIPTIONS

HASSALSTRONGYLUS PUNTANUS N. SP. (Figs 1-11) Type-material: male holotype, female allotype CHMLP 3 4 5 9 / l a . Paratypes: three males, five females CHMLP 3 4 5 9 / l b , three males, five females MNHN 6 7 2 K Q . Coparasites o f 5. azarai Durette-Desset & Sutton, 1985.

Type-host: Graomys griseoflavus ( W a t e r h o u s e , 1 8 3 7 ) (Muridae, S i g m o d o n t i n a e ) .

Site: small intestine.

Type-locality: San F r a n c i s c o del Monte de O r o ( 3 2 ° 3 6 ' S, 6 6 ° 0 8 ' W ) , Province o f San Luis, Argentina.

V o u c h e r material: five males, four females CHMLP 3 4 6 0 / 1 , coparasites o f S. azarai; three males, four females CHMLP 3 4 6 1 ; six males, 14 females CHMLP 3 4 6 2 / 1 , coparasites o f S. azarai; o n e female CHMLP 3 4 7 6 / 1 ; three males, three females CHMLP 3477; o n e male, o n e female CHMLP 3 4 7 8 ; six males, 15 females MNHN 6 7 3 K Q , three males, three females MNHN 6 7 4 KQ. S a m e host and locality.

Prevalence and intensity o f infection: 8 7 . 5 % o f the hosts (seven out o f eight) w e r e infected, harbouring 1-42 w o r m s ( m e a n = 1 3 . 3 ) .

DESCRIPTION

Small n e m a t o d e s , loosely coiled sinistrally along ven

tral side. Excretory pore situated within distal third o f o e s o p h a g u s length. Deirids at s a m e level as excretory pore or slightly anterior or posterior to it (Fig. 1 ) .

Head: c e p h a l i c vesicle present. In apical view, trian

gular buccal opening surrounded by very thin ring. Pre

s e n c e o f two amphids, six interno-labial papillae, the medio-lateral c l o s e r to e a c h o t h e r than to lateral, four externo-labial papillae (the two lateral probably fused with amphids), and four submedian c e p h a l i c papillae (Fig. 2 ) .

Synlophe: (studied in two male and t w o female para

types). In both s e x e s cuticle bearing longitudinal, unin

terrupted ridges appearing posterior to cephalic vesicle, up to about 100 µm posterior to o e s o p h a g o intestinal junction, disappearing just anterior to caudal bursa in male and at caudal e n d in female. N u m b e r o f ridges;

19 in male and 20 in female at level o f o e s o p h a g o - intestinal junction (Figs 3 - 4 ) , 24 in male and 25 in female at mid-body (Figs 5 - 6 ) , 24 in male and 19 in female at posterior end. At mid-body, ridges o f similar size, e x c e p t for those o f ventral right quadrant, slightly smaller, and for dorsal ridge adjacent to right ridge, larger than the others. At posterior end, ridges of equal size in male and unequal in female (Figs 7 - 8 ) . Axis o f orientation o f ridges directed from ventral right to dorsal left quadrant with inclination o f about 4 8 ° to sagittal axis in male and 6 0 ° in female at o e s o p h a g o - intestinal junction. At mid-body axis o f orientation o f ridges with different inclination o n ventral and dorsal sides, o f about 53° to sagittal axis in male and 5 9 ° in female in ventral right quadrant and 7 9 ° in both s e x e s in dorsal left quadrant. At posterior end, most ridges oriented perpendicularly to b o d y surface.

Holotype male: 3.3 mm long and 150 w i d e at mid- body, cephalic vesicle 6 5 long and 35 wide, nerve ring, excretory pore and deirids situated at 170, 2 7 5 and 265 from a p e x , respectively. O e s o p h a g u s 3 4 0 long.

Sub-symmetrical caudal bursa, with pattern o f type 1- 3-1 (Fig. 9 ) . Prebursal papillae not observed. Rays 3 and 6 arising at s a m e level from c o m m o n trunk o f rays 3 to 6; rays 4 slightly longer than rays 5, both divergent at their distal third. Rays 8 strongly reinforced at b a s e , arising from b a s e o f dorsal ray. Dorsal ray divided at mid-length into t w o b r a n c h e s , e a c h b r a n c h divided into t w o s u b e q u a l s u b - b r a n c h e s : e x t e r n a l (rays 9 ) slightly longer than internal (rays 1 0 ) . Genital c o n e 4 5 long by 4 0 w i d e at b a s e , with strongly scle- rotised walls, bearing papilla 0 o n ventral lip and t w o rounded papillae 7 o n dorsal lip (Fig. 1 0 ) . Thin alate subequal spicules, 4 5 0 long, ending in sharp tip (Fig. 10).

G u b e r n a c u l u m 17 long and 12 wide at b a s e in ventral view (Fig. 1 0 ) .

Measurements ( r a n g e and a v e r a g e ) o f six male para

types: 3.3-4.1 ( 3 . 5 2 ) mm long and 1 0 0 - 1 5 0 ( 1 4 2 ) w i d e at midbody. Cephalic vesicle 6 0 - 6 5 ( 6 3 ) long and 3 0 - 4 0 ( 3 5 ) wide. Nerve ring, excretory p o r e and deirids situated at 1 3 5 - 1 9 0 ( 1 6 6 ) , 2 1 0 - 2 8 0 ( 2 4 9 ) and 2 1 0 - 2 8 0 ( 2 5 0 ) from a p e x , respectively. O e s o p h a g u s 3 3 0 - 3 5 0 ( 3 4 0 ) long. Spicules 3 9 0 - 4 5 0 ( 4 1 7 ) long.

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Figs 1-11. - H a s s a l s t r o n g y l u s puntanus n. s p . from Graomys griseoflavus.

1, m a l e , a n t e r i o r e x t r e m i t y , right lateral v i e w . 2, f e m a l e , h e a d , a p i c a l v i e w . 3 - 8 , t r a n s v e r s e s e c t i o n s o f b o d y ( l a r g e s t ridge s h a d e d ) ; 3-4 at o e s o p h a g o - i n t e s t i n a l j u n c t i o n , 3, m a l e , 4 , f e m a l e ; 5 - 6 , at m i d - b o d y . 5. m a l e , 6, f e m a l e ; 7 - 8 , at p o s t e r i o r e n d , 7, m a l e , 2 0 0 µm a n t e r i o r to c a u d a l b u r s a . 8. f e m a l e , just a n t e r i o r t o vulva. 9, m a l e , c a u d a l b u r s a , ventral v i e w . 1 0 a , m a l e , g e n i t a l c o n e , left lateral v i e w , 1 0 b , m a l e , g e n i t a l c o n e , v e n t r a l v i e w . 1 1 a , g r a v i d f e m a l e , p o s t e r i o r e x t r e m i t y , left lateral v i e w , 11b, n o n - g r a v i d f e m a l e , p o s t e r i o r e x t r e m i t y , s c h e m a of p r o x i m a l part of i n f u n d i b u l u m a n d distal part o f u t e r u s , t r a n s v e r s a l l y e n l a r g e d .

A b b r e v i a t i o n s : r. right, v. ventral. S c a l e b a r s : 1. 5 0 µm; 2. 10. 10 µm: 3. 4 , 7, 8, 2 0 µm; 5, 6, 2 5 µm; 9 . 11a. 100 µm.

Two N E W N I P P O S T R O N G Y L I N A E F R O M A R G E N T I N A

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DIGIANI M.C. & DURETTE-DESSET M.C.

Allotype female: 6.65 mm long and 2 0 0 wide at mid- body. Cephalic vesicle 7 0 long and 3 5 wide. Nerve ring, e x c r e t o r y pore and deirids situated at 190, 2 7 0 and 260 from a p e x , respectively. O e s o p h a g u s 3 9 5 long.

M o n o d e l p h i c . Vulva situated at 2 2 0 from caudal extre

mity. Vagina vera 25 long, vestibule 9 0 , sphincter 35 long and 3 0 wide, infundibulum 8 5 long (Fig. 1 1 a ) . In non-gravid females, proximal part o f infundibulum and distal part o f uterus transversally enlarged (Fig. 11b).

In gravid females, infundibulum usually folded and e n l a r g e m e n t not clearly observed. Uterus 6 0 0 long, taking up 9 % o f b o d y length, containing 11 e m b r y o - nated eggs, 6 5 long and 4 0 wide. Tail conical, non- retractile, 4 5 long (Fig. 1 1 a ) .

Measurements (range and a v e r a g e ) o f 10 female paratypes: 5.00-7.45 (6.13) mm long and 130-200 ( 1 7 1 ) wide at mid-body. Cephalic vesicle 6 0 - 7 5 (66) long and 3 5 - 50 ( 4 1 ) wide. Nerve ring, excretory pore and deirids situated at 150-180 ( 1 6 8 ) , 2 4 0 - 2 8 0 ( 2 6 8 ) and 2 4 0 - 2 8 0 ( 2 6 8 ) from a p e x , respectively. O e s o p h a g u s 3 5 0 - 4 4 0 ( 3 9 3 ) long. Vulva situated at 180-230 ( 2 0 4 ) from caudal extremity. Vagina vera 2 0 - 3 0 ( 2 5 ) long, vestibule 8 0 - 100 ( 8 7 ) , sphincter 3 0 - 4 0 ( 3 4 ) long and 3 0 - 4 0 ( 3 7 ) wide, infundibulum 8 0 - 1 4 0 ( 1 0 9 ) . Uterus 6 5 0 - 9 3 0 ( 7 6 3 ) long, taking up 10-16 % ( 1 3 % ) o f b o d y length. Number o f eggs 2 5 - 4 8 ( 3 8 ) , e m b r y o n a t e d , 50-75 ( 6 2 ) long and 3 0 - 4 2 ( 3 7 ) wide. Tail 3 5 - 5 0 ( 4 4 ) long.

DISCUSSION

B y the characters o f the s y n l o p h e ( n u m b e r o f ridges b e t w e e n 19-25, unequal in size) and o f the caudal bursa (symmetrical, with genital c o n e n o n hypertro- p h i e d ) . the studied s p e c i m e n s may b e included in the American genus Hassalstrongylus Durette-Desset, 1971a.

(Heligmonellidae, Nippostrongylinae), including 16 spe

cies. Thirteen w e r e described from the Sigmodontinae, o n e from the Sigmodontinae and the Arvicolinae, o n e from the Sigmodontinae and Mus musculus, and o n e from Mus musculus.

Only five s p e c i e s o f Hassalstrongylus share with the s p e c i m e n s here described a sub-symmetrical caudal bursa with a pattern o f type 1-3-1 for e a c h lobe. T h e s e species are H. argentinus (Freitas, Lent & Almeida, 1937), a parasite o f Holochilus balnearum from Argentina, H. dollfusi (Diaz-Ungria, 1963), a parasite o f Mus mus

culus from Venezuela, H. echalieri Diaw, 1976, a para

site o f Oryzomys sp. from French Guyana, H. musculi (Dikmans, 1 9 3 5 ) , a parasite o f Mus musculus and Ory

zomys palustris from USA, and H. scbadi (Durette- Desset, 1 9 7 1 b ) , a parasite o f Nectomys alfari from Colombia.

T h e s p e c i m e n s from G. griseoflavus differ from the a b o v e m e n t i o n e d s p e c i e s by rays 2 b e i n g well-deve

loped and o f equivalent size to rays 3. In addition, they

differ from H. argentinus, H. echalieri and H. musculi b y the n u m b e r o f ridges o f the s y n l o p h e ( 2 4 - 2 5 vs.19- 2 2 ) .

In H. schadi and H. dollfusi the caudal bursa is trans

versally elongated, and rays 6 are less d e v e l o p e d than rays 5, as in the specimens from G. griseoflavus. H o w e  ver, H. schadi is distinguished by the triangular tip o f the spicules and the indentation o n the lip o f the genital c o n e . Hassalstrongylus dollfusi, the most similar s p e c i e s , also p o s s e s s e s the character o f rays 8 reinfor

c e d at b a s e , but rays 4 are strongly directed anteriorly and m u c h longer than rays 5, the proximal half o f the dorsal ray is enlarged and the female tail is retractile.

W e c o n s i d e r thus the s p e c i m e n s found in G. griseo

flavus to b e l o n g to a n e w s p e c i e s that w e have n a m e d Hassalstrongylus puntanus n. sp. in reference to people born in San Luis Province, w h o are called "puntanos".

STILESTRONGYLUS FRANCISCANUS N . SP.

(Figs 1 2 - 2 4 )

Type-material: male holotype, female allotype CHMLP 3 4 6 5 / 1 a . Paratypes: two males, o n e female CHMLP 3 4 6 5 / 1 b ; o n e male MNHN 6 7 5 K Q .

Type-host: Graomys griseoflavus ( W a t e r h o u s e , 1 8 3 7 ) (Muridae, S i g m o d o n t i n a e ) .

Type-locality: San Francisco del Monte de O r o ( 3 2 ° 36' S, 6 6 ° 0 8 ' W ) , Province o f San Luis, Argentina.

P r e v a l e n c e and intensity o f infection: 12.5 % o f the hosts ( o n e out o f eight) was infected with six speci

mens.

DESCRIPTION

Small n e m a t o d e s , tightly (females) or loosely ( m a l e s ) coiled sinistrally along ventral side. Excretory pore situated within distal third o f o e s o p h a g u s length. Dei

rids at s a m e level as excretory pore (Fig. 1 2 ) or slightly posterior to it.

Head: c e p h a l i c vesicle present. In apical view, trian

gular buccal opening surrounded by very thin ring. Pre

s e n c e o f two amphids, six interno-labial papillae, the medio-lateral closer to e a c h other than to lateral, four externo-labial papillae (the two lateral p r o b a b l y fused with amphids), and four submedian c e p h a l i c papillae.

Externo-labial and c e p h a l i c papillae c o n n e c t e d two to two by cuticular structures in arc o f circle, resembling cuticular c o r d o n s (Fig. 1 3 ) .

Synlophe: (studied in two male and o n e female para

types). In both s e x e s cuticle bearing longitudinal, unin

terrupted ridges appearing posterior to cephalic vesicle up to about 100 µm posterior to oesophago-intestinal junction, disappearing just anterior to caudal bursa in male and at caudal e n d in female. N u m b e r o f ridges:

22 in m a l e and 24 in female at level o f o e s o p h a g o - intestinal junction (Figs 1 4 - 1 5 ) , 27 in male and 2 8 in

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ro N E W N I P P O S T R O N G Y U N A E F R O M A R G E N T I N A

F i g s 1 2 - 2 4 . - Stilestrongylus franciscanus n. s p . from Graomys griseoflavus.

12, m a l e , a n t e r i o r e x t r e m i t y , left lateral v i e w . 13. f e m a l e , h e a d , a p i c a l v i e w . 1 4 - 1 7 , t r a n s v e r s e s e c t i o n s o f b o d y (largest ridge s h a d e d ) : 1 i- 1 5 , at o e s o p h a g o - i n t e s t i n a l j u n c t i o n . 14, m a l e . 1 5 . f e m a l e : 1 6 - 1 7 . at m i d - b o d y . 1 6 . m a l e , 1 7 , f e m a l e ; 1 8 - 1 9 , at p o s t e r i o r e n d , 1 8 , m a l e , 1 8 0 µm a n t e r i o r t o c a u d a l b u r s a , 1 9 . f e m a l e , distal part o f u t e r u s , at 3 2 0 µm from p o s t e r i o r e n d . 2 0 - 2 2 , m a l e , c a u d a l b u r s a , 2 0 , l a t e r o - d o r s a l v i e w , 2 1 , right l o b e , l a t e r o - d o r s a l v i e w (left l o b e in d o t t e d l i n e s ) , 2 2 , left l o b e , l a t e r o - d o r s a l v i e w (right l o b e a n d g e n i t a l c o n e in d o t t e d l i n e s ) . 2 3 , g e n i t a l c o n e , v e n t r o - l a t e r a l v i e w . 2 4 , f e m a l e , p o s t e r i o r e x t r e m i t y , right lateral v i e w .

A b b r e v i a t i o n s : r. right, v. v e n t r a l . S c a l e b a r s : 1 2 , 5 0 µm; 1 3 . 1 0 µm; 1 4 - 1 9 , 2 3 , 2 0 µm; 2 0 - 2 2 , 2 4 , 1 0 0 µm.

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female at mid-body (Figs 1 6 - 1 7 ) , 25 in male and 24 in female at posterior e n d (Fig. 1 8 - 1 9 ) . Ridges o f similar size, e x c e p t t h o s e o f ventral right quadrant w h i c h are slightly smaller, and for dorsal ridge adjacent to left ridge, w h i c h is larger than the rest. Axis o f orientation o f ridges directed from ventral right to dorsal left qua

drant with inclination o f about 5 2 ° to sagittal axis in male and 5 8 ° in female at oesophago-intestinal junc

tion and about 7 0 ° to sagittal axis in male and 7 6 ° in female at mid-body (Figs 1 4 - 1 7 ) . At posterior end, axis o f orientation o f about 4 2 ° in male and ridges oriented perpendicularly to b o d y surface in female.

Holotype male: 3.65 m m long and 120 wide at mid- body, cephalic vesicle 6 0 long and 3 0 wide. Nerve ring, excretory pore and deirids situated at 170, 2 6 5 and 2 6 5 from a p e x , respectively. O e s o p h a g u s 3 0 0 long.

Caudal bursa bell-shaped, with pattern o f type 1-4 (rays 2 arising first from c o m m o n trunk o f rays 2 to 6 ) , asymmetrical with hypertrophied right lobe (Figs 2 0 - 2 2 ) . Prebursal papillae not observed. Right l o b e : ari

sing o f rays 2 and 3 from c o m m o n trunk very distant;

ray 3 arising more distally than ray 6; rays 4 and 5 diver

gent at extremity (Fig. 2 1 ) . Left lobe: rays 2 and 3 diver

gent in V; rays 3 and 6 divergent at s a m e level from c o m m o n trunk; rays 4 and 5 divergent at extremity (Fig. 2 2 ) . Right ray 8 thin, arising from proximal third o f dorsal ray, left ray 8 robust, arising at b a s e from dorsal ray, both rays 8 longer than dorsal ray. Dorsal ray divided at mid-length into two b r a n c h e s , e a c h branch divided into two subequal sub-branches: exter

nal (rays 9 ) slightly longer than internal (rays 1 0 ) . Genital c o n e well-developed, 100 long b y 60 wide at b a s e (Fig. 2 3 ) . Papillae 0 and 7 not observed. Thin alate s u b e q u a l s p i c u l e s , 5 8 0 long, e n d i n g in s h a r p tip (Fig. 2 3 ) . Gubernaculum long and slender, 3 0 long and 10 w i d e at b a s e in ventral view (Fig. 2 3 ) .

Measurements (range and average) o f three male paratypes: 3.4-3.7 ( 3 . 5 6 ) m m long and 1 1 0 - 1 4 0 ( 1 2 3 ) w i d e at mid-body. Cephalic vesicle 50-65 ( 5 8 ) long and 2 2 - 4 0 ( 3 1 ) wide. Nerve ring, excretory pore and deirids situated at 150-170 ( 1 6 0 ) , 2 6 0 - 2 7 0 ( 2 6 7 ) and 2 6 0 - 2 8 0 ( 2 7 0 ) from a p e x , respectively. O e s o p h a g u s 3 0 0 - 3 3 0 ( 3 1 0 ) long. Spicules 5 5 0 - 5 8 0 ( 5 7 0 ) long.

Allotype female: 4.85 mm long and 110 wide at mid- body. Cephalic vesicle 6 0 long and 35 wide. Nerve ring, excretory pore and deirids situated at 170, 2 6 0 and 2 6 0 from a p e x , respectively. O e s o p h a g u s 3 0 0 long.

M o n o d e l p h i c . Posterior end retracted up to level o f vulva. Vulva situated at 7 0 from caudal extremity.

Vagina vera 25 long, vestibule 6 5 , sphincter 4 0 long and 35 wide, infundibulum 180 long. Uterus 8 0 0 long, taking up 16 % o f b o d y length, containing 3 0 eggs, at morula stage, 60-70 long and 4 0 - 4 5 wide. Tail conical, 30 long, bearing a m u c r o n (Fig. 2 4 ) .

Measurements o f the female paratype: 4.5 mm long and 100 wide at mid-body. Cephalic vesicle 6 0 long and

35 wide. Nerve ring, excretory pore and deirids situated at 150, 2 2 5 and 235 from a p e x , respectively. O e s o phagus 2 9 0 long. Vulva situated at 7 0 from caudal extremity. Vagina vera 25 long, vestibule 7 0 , sphincter 4 0 long and 4 0 wide, infundibulum 175 long. Uterus 8 2 0 long, taking up 18 % o f b o d y length, containing 28 eggs 4 5 - 5 0 long and 30-35 wide. Tail 4 0 long.

DISCUSSION

B y the characters o f the s y n l o p h e ( n u m b e r o f ridges from 23 to 3 0 , small, o f equivalent size) and of the caudal bursa (asymmetrical, with hypertrophied genital c o n e ) , the studied s p e c i m e n s m a y b e included in the genus Stilestrongylus Freitas, Lent & Almeida, 1937 ( H e l i g m o n e l l i d a e , N i p p o s t r o n g y l i n a e ) , including 19 Neotropical species, 18 parasitic in the Sigmodontinae and o n e in the Echimyidae.

A m o n g these s p e c i e s , four along with the s p e c i m e n s here described share the following characters: caudal bursa o f type 1-4 in both lobes; strongly asymmetrical caudal bursa with hypertrophied right lobe; right rays 4 and 5 o f equivalent length and divergent at extremity.

T h r e e o f these species c o m e from Argentina: S. aureus Durette-Desset & Sutton, 1 9 8 5 , a parasite o f Reithrodon auritus; S. azarai Durette-Desset & Sutton, 1 9 8 5 , a parasite o f Akodon azarae; S. oryzomysi Sutton &

Durette-Desset, 1991, a parasite o f Oryzomys flavescens;

and the fourth, S. flavescens Sutton & Durette-Desset, 1991, a parasite o f Oryzomys flavescens, from Uruguay.

Stilestrongylus aureus, S. azarai and S. oryzomysi differ from the s p e c i m e n s from Graomys griseoflavus mainly b y having a caudal bursa with a long dorsal ray, and rays 6 forming a lateral trident with rays 4 and 5. Sti

lestrongylus flavescens is the most similar species, but it differs from our s p e c i m e n s mainly by the pattern o f the right l o b e : rays 2 and 3 are divergent in "V" and ray 3 arises from the c o m m o n trunk o f rays 3 to 6 more proximally than ray 6 (vs. m o r e distally in our speci

m e n s ) . T h e s p e c i m e n s from G. griseoflavus are thus considered to b e l o n g to a n e w species, which w e have named Stilestrongylus franciscanus n. sp., after the type locality.

T w o other s p e c i e s , S. scapteromys Suriano & Navone, 1996, parasitic in Scapteromys aquaticus from Argen

tina, and S. peromysci F a l c o n Ordaz & Sanabria, 1999, parasitic in Peromyscus difficilis from M e x i c o , p o s s e s s a strongly asymmetrical caudal bursa with a hypertro

phied right l o b e , but the descriptions are insufficient to b e able to determine the pattern o f the caudal bursa.

H o w e v e r , they can b e distinguished from S. francis

canus n. sp. by the n u m b e r o f cuticular ridges of the s y n l o p h e ( 1 6 - 1 8 in S. scapteromys and 3 0 in S. pero

mysci).

It is interesting to n o t e that in females o f the s p e c i e s m e n t i o n e d in the discussion, with the e x c e p t i o n o f

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TWO NEW NlPPOSTRONGYLINAE FROM ARGENTINA

S. scapteromys, the tail is retracted up to the level o f the vulva. In a cladistic analysis o f the g e n u s Stiles- trongylus (Pérez-Ponce de León et al., 2 0 0 0 ) , the retrac

tile tail w a s o n e o f the s y n a p o m o r p h i e s supporting a m o n o p h y l e t i c group c o m p o s e d o f S. azarai, S. aureus, S. flavescens, S. oryzomysi, S. freitasi Durette-Desset,

1968, a parasite o f Zygodontomys lasiunts and Ory- zomys subflavus from Brazil, S. inexpectatus Durette- Desset & Tchéprakoff, 1969, a parasite o f Trichomys apereoides from Brazil, and S. moreli Diaw, 1 9 7 6 , a parasite o f Phyllotis boliviensis from Bolivia. This cha

racter was also attributed to S. bidalguensis F a l c ó n - Ordaz & Sanabria, 1 9 9 9 (Fig. 2 d ) , a parasite o f Pero- myscus sp. from M e x i c o , e v e n w h e n , after the original illustration, the female tail is not retracted in this s p e cies w h e r e a s , o n the contrary, it is retracted in S. pero- mysci, a parasite o f Peromyscus difficilis from M e x i c o (Falcón-Ordaz & Sanabria, 1 9 9 9 , Fig. 1 c ) .

Another interesting character in S. franciscanus n. sp.

is the dorsal ridge adjacent to the left ridge being larger than the others, a character shared with S. flavescens and S. oryzomysi.

STILESTRONGYLUS AZARAI

DURETTE-DESSET & SUTTON, 1 9 8 5 (Figs 2 5 - 3 6 ) Material studied: three females CHMLP 3 4 5 9 / 2 , copara- sites o f H. puntanus n. sp.; two males, o n e female CHMLP 3 4 6 0 / 2 , coparasite o f H. puntanus n. sp; o n e female CHMLP 3462, coparasites o f H. puntanus n. sp.

from San Francisco del Monte de O r o ( 3 2 ° 3 6 ' S, 6 6 ° 08' W ) , Province o f San Luis, Argentina; four males, four females CHMLP 3468; 15 males, 24 females CHMLP 3 4 7 2 / 1 ; 10 males, 10 females MNHN 6 7 6 KQ; two males, five females MNHN 677 KQ from San Luis Capital ( 3 3 ° 19' S, 6 6 ° 2 1 ' W ) , Province o f San Luis, Argentina.

Host: Graomys griseoflavus ( W a t e r h o u s e , 1 8 3 7 ) (Muri- dae, S i g m o d o n t i n a e ) .

Prevalence and intensity o f infection: 3 7 . 5 % o f the hosts (three out o f eight) from San Francisco del Monte d e O r o w e r e infected, with intensities o f infection o f one-three w o r m s . 33-3 % o f the hosts ( t w o out o f s i x ) from San Luis Capital w e r e infected, with intensities o f infection o f 15-59 worms.

ADDITIONAL MORPHOLOGICAL DATA

Head; cephalic vesicle present (Fig. 2 5 ) . In apical view, triangular b u c c a l o p e n i n g surrounded by very thin ring. P r e s e n c e o f t w o a m p h i d s , six i n t e r n o - l a b i a l papillae, the s u b m e d i a n c l o s e r to e a c h other than to lateral, four externo-labial papillae (the t w o lateral probably fused with amphids), and four submedian cephalic papillae. Externo-labial and c e p h a l i c papillae c o n n e c t e d two to two b y w e a k cuticular structures in arc o f circle, resembling cuticular c o r d o n s (Fig. 2 6 ) .

Synlophe: (studied in two males and two females).

N u m b e r o f ridges: 18 in male and 21 in female at level o f oesophago-intestinal junction (Figs 27-28), 26 in male and 2 8 in female at mid-body (Figs 2 9 - 3 0 ) and at pos

terior end (Figs 3 1 - 3 2 ) . Ridges o f similar size, e x c e p t for those o f ventral right quadrant, slightly smaller. Axis o f orientation o f ridges directed from ventral right to dorsal left quadrant, with inclination o f about 5 3 ° to sagittal axis in both s e x e s at oesophago-intestinal junc

tion and 6 5 ° in male at mid-body. In female, at mid- body, axis o f orientation o f ridges with different incli

nation o n ventral and dorsal sides, of about 4 5 ° on right ventral quadrant, and subfrontal o n left dorsal quadrant. At posterior end, axis o f orientation o f about 8 3 ° in male and ridges oriented perpendicularly to b o d y surface in female (Figs 3 1 - 3 2 ) .

Measurements (range and a v e r a g e ) o f 10 males: 3-0- 4.0 (3.33) mm long and 120-150 ( 1 3 2 ) wide at mid-body.

Cephalic vesicle 55-65 ( 6 1 ) long and 3 0 - 4 0 ( 3 3 ) wide.

Nerve ring, e x c r e t o r y p o r e and deirids at 1 4 0 - 1 7 5 ( 1 5 5 ) , 220-260 ( 2 3 9 ) and 2 2 0 - 2 6 0 ( 2 3 9 ) from a p e x , res

pectively. O e s o p h a g u s 2 9 0 - 3 1 0 ( 3 0 0 ) long. Spicules 4 4 0 - 4 8 0 ( 4 5 6 ) long.

Measurements (range and a v e r a g e ) o f 10 females: 4 . 5 - 5.7 ( 5 . 1 ) mm long and 100-140 ( 1 2 1 ) wide at mid-body.

Cephalic vesicle 50-75 ( 6 3 ) long and 3 5 - 5 0 ( 3 8 ) wide.

Nerve ring, e x c r e t o r y p o r e and deirids at 1 2 0 - 1 7 0 ( 1 4 8 ) , 190-240 ( 2 2 0 ) and 190-240 ( 2 2 0 ) from a p e x , res

pectively. O e s o p h a g u s 3 2 5 - 3 6 0 ( 3 4 4 ) long. Vulva at 7 0 - 100 ( 8 2 ) from caudal extremity. Vagina vera 20-30 ( 2 4 ) long, vestibule 55-75 ( 6 2 ) , sphincter 3 0 - 4 0 ( 3 8 ) long and 40-40 ( 4 0 ) wide, infundibulum 90-110 ( 1 0 4 ) . Uterus 8 0 0 - 9 8 0 ( 8 7 4 ) long, taking up 15-19 % (17 % ) o f b o d y length. Number o f eggs 24-43 ( 3 1 ) , embryonated, 5 5 - 70 long and 35-45 wide. Tail 20-25 ( 2 2 ) long.

DISCUSSION

T h e s p e c i m e n s studied are identified, both by the cha

racters o f the s y n l o p h e and those o f the caudal bursa, as Stilestrongylus azarai Durette-Desset & Sutton, 1985, a parasite o f Akodon azarae from the province o f B u e n o s Aires, Argentina. Slight differences may b e found in the position o f the nerve ring (within proximal third o f o e s o p h a g u s in s p e c i m e n s from A. azarae vs.

middle third in our s p e c i m e n s ) and the excretory pore (within middle third o f o e s o p h a g u s in s p e c i m e n s from A. azarae vs. distal third in our s p e c i m e n s ) . O n the other hand, in females, the uterus contains six eggs and takes up 9 % o f body length in specimens from A. aza

rae, w h e r e a s in our s p e c i m e n s the uterus contains 2 4 - 43 eggs, taking up 15-21 % o f b o d y length. However, these are the only differences and s e e m o f insufficient importance to create a n e w s p e c i e s , and w e attribute the s p e c i m e n s from Graomys griseoflavus to S. azarai.

With the present report, the host and geographical range for S. azarai is enlarged.

P a r a s i t e . 2 0 0 3 , 10. 2 1 - 2 9

Mémoire 27

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F i g s 25-36. - Stilestrongylus azami D u r e t t e - D e s s e t & Sutton, 1 9 8 5 from Graomys griseoflavus.

2 5 , m a l e , a n t e r i o r e x t r e m i t y , right lateral v i e w . 2 6 , f e m a l e , h e a d , a p i c a l v i e w . 2 7 - 3 2 . t r a n s v e r s e s e c t i o n s of b o d y ; 2 7 - 2 8 , at o e s o p h a g o - i n t e s - tinal j u n c t i o n , 2 7 , m a l e , 2 8 , f e m a l e ; 2 9 - 3 0 . at m i d - b o d y , 2 9 , m a l e , 3 0 , f e m a l e ; 3 1 - 3 2 , at p o s t e r i o r e n d , 3 1 , m a l e , 3 5 0 µm a n t e r i o r t o c a u d a l b u r s a , 3 2 , f e m a l e , at 2 5 0 µm from p o s t e r i o r e n d . 33-34, m a l e , c a u d a l b u r s a , 3 3 , right l o b e , dorsal v i e w (left rays in d o t t e d l i n e s ) , 34, left l o b e , d o r s a l v i e w (right rays in d o t t e d l i n e s ) . 3 5 a , m a l e , g e n i t a l c o n e , lateral v i e w . 3 5 b . m a l e , g e n i t a l c o n e , ventral v i e w . 36, f e m a l e , p o s - t e r i o r e x t r e m i t y , left lateral v i e w .

A b b r e v i a t i o n s : r, right, v. v e n t r a l . S c a l e bars: 2 5 , 5 0 µm; 26, 10 µm; 2 7 - 3 2 , 3 5 , 2 0 µm; 3 3 - 3 4 , 3 6 , 1 0 0 µm.

D I G I A N I M . C . & D L T Œ T T E - D E S S E T M . C .

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TWO NEW NlPPOSTRONGYlINAE FROM ARGENTINA

ACKNOWLEDGEMENTS

T

h e authors wish to thank Dr Cristina D a m b o - renea, curator o f the Helminthological Collection of the Museo d e La Plata, Argentina, for the loan of the s p e c i m e n s for study. T h a n k s are also due to the staff o f t h e Instituto Miguel Lillo. S a n Miguel d e T u c u m á n , Argentina, for collecting and providing t h e hosts.

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Reçu le 7 septembre 2 0 0 2

Accepté le 12 décembre 2002

Mémoire 29

P a r a s i t e . 2 0 0 3 . 7 0 2 1 - 2 9