LLNSTOWINEMA BREVE
N . S P . ( NEM A T O D A : SEU R A T I D A E)A
P A R A S I T EOF ANTECHINUS AGILIS ( M A R S U P I A L I A : DASYURIDAE) FROM A U S T R A L I A
SMALES L.R.*
Summary:
A new echinonematine nematode, Linstowinema breve sp. n., from the small intestine of the dasyurid marsupial Anthechinus agilis is described. The species is distinguished from its congeners by the possession of the following suite of characters: small size; first and third row of cephalic hooks similar in size; second row larger; 1 3-
15 rows of body hooks without undulating edges on the dilated cuticle of the oesophageal region; oesophagus terminating at the level of the 5th-7th row of body hooks; ten pairs of caudal papillae; a large pair of lateral ad-cloacal papillae extend into small lateral alae. linstowinema larvae previously recorded from A. agilis may be the same species. A key to species of the genus Linstowinema is provided.
KEY WORDS : Linstowinema, Seuratidae, nematode, dasyurid, marsupial, Australia.
Résumé :
LINSTOWNEMA BREVE N. SP. (NEMATODA: SEURATIDAE), PARASITE D'ANTECHINUS AGILIS EN AUSTRALIEDescription de Linstownema breve n. sp. (Echinonematinae) parasite de l'intestin grêle du marsupial Dasyuridae Antechinus agilis en Australie. L'espèce se distingue de ses congénères par les caractères suivants : petite taille, crochets de la première et troisième rangée de même taille, plus petits que ceux de la deuxième rangée, cuticule de la région œsophagienne légèrement dilatée, portant 13 à 15 files de crochets sans ondulations sur leur racine, fin de l'œsophage au niveau des 5-7es rangées de crochets somatiques, dix paires de papilles caudales avec une grande paire latérale ad-cloacale soulevant de petites ailes latérales. La larve de Linstownema décrite précédemment chez le même hôte pourrait appartenir à la même espèce. Une clé de détermination des espèces de Linstownema est présentée.
MOTS CLÉS : Linstowinema, Seuratidae, nématode, dasyures, marsupiaux australiens.
INTRODUCTION MATERIALS AND METHODS
D
uring investigations into the helminth fauna o f dasyurid marsupials in Australia s p e c i m e n s o f an e c h i n o n e m a t i n e ( N e m a t o d a : S e u r a t i d a e ) w e r e f o u n d in an individual o f Antechinus agilis D i c k m a n , Parnaby, Crowther & King, 1 9 9 8 from N e w South W a l e s . Having characters typical o f the g e n u s Linstowinema Smales, 1 9 9 7 ( s e e Smales, 1 9 9 9 ) w h i c h has b e e n found in dasyurids ( C h a b a u d et al., 1 9 8 0 , Smales 1 9 9 9 ) , t h e s e s p e c i m e n s w e r e sufficiently diffe- rent to b e c o n s i d e r e d a n e w s p e c i e s . This s p e c i e s is d e s c r i b e d b e l o w .* School of Biological and Environmental Sciences, Central Queens- land University, Rockhampton, Queensland, 4702 Australia.
Correspondence: Lesley Warner.
Tel: (07) 49 309 641 - Fax: (07) 49 309 209.
Email: l.warner@cqu.edu.au
T
h e s p e c i m e n s w e r e fixed in hot 10 % formalin b e f o r e storing in 7 0 % a l c o h o l and clearing in l a c t o p h e n o l prior to e x a m i n a t i o n . All m e a s u r e - m e n t s are given, as the range followed b y the m e a n in p a r e n t h e s e s , in millimetres, unless otherwise stated.Drawings w e r e m a d e with the aid o f an O l y m p u s m i c r o s c o p e drawing tube.
RESULTS
LINSTOWINEMA BREVE SP. N.
(Figs 1 - 1 0 )
D
escription: small n e m a t o d e s , anterior e n d with c e p h a l i c b u l b bearing three rows o f 14 ( m a l e ) or 16 (female) files o f large h o o k s , s e c o n d r o w longest. Mouth o p e n i n g triangular in outline, without lips o r lip-like structures. F o u r d o u b l e s u b m e d i a n papillae, o n e pair amphids. N e c k with 3-6 rows o f tiny spines. O e s o p h a g e a l region with slight cuticular dila- tion bearing 13-15 rows o f 14 (male) or 16 (female) filesParasite, 1999, 6, 329-332
Mémoire
329Article available athttp://www.parasite-journal.orgorhttp://dx.doi.org/10.1051/parasite/1999064329
Figs 1-10. - Linstowinema breve sp. n. 1. Anterior end of male, dorsal view; Bar = 200 um. 2. Cephalic end of male, optical section dorsal view; Bar = 50 um. 3. Body hooks, dorsal view; Bar = 25 |im,
4. Body hooks, lateral view; Bar = 25 um. 5. Tip of female tail, lateral view; Bar = 25 um. 6. Gubernaculum, ventral view; Bar = 12 um.
7. Tail of male, lateral view right side; Bar = 100 pm, 8. Vagina, lateral view right side; Bar = 50 um. 9. Tail of female, lateral view left side; Bar = 100 pm. 10. Tail of male, cloacal region ventral view; Bar - 50 pm.
330 Mémoire Parasite, 1999, 6, 329-332
SMALES L.R.
LINSTOWINEMA BREVE N. SP.
o f b o d y h o o k s ; first and last rows smallest, 4th and 5th rows largest; roots o f h o o k s without undulating e d g e s ; remainder o f b o d y with up to 3 0 files o f spines over entire b o d y surface (female) or 9 5 % b o d y surface dor- sally, reaching to level o f anterior pair o f caudal papillae ventrally ( m a l e ) . O e s o p h a g u s simple, club-shaped, ter
minating about level with 5t h - 7t h row o f hooks, within anterior b o d y dilation; V7 - V9 b o d y length. Nerve ring not s e e n ; excretory pore in n e c k ; deirids conical, bet
w e e n 1st and 2nd rows o f b o d y h o o k s .
M a l e ( t w o s p e c i m e n s ) : l e n g t h o f b o d y 4 . 9 , 4 . 2 , maximum width 0.290, 0.255. Cephalic bulb 0.255 long b y 0.168 wide; cephalic h o o k s 1st row 0.076, 0.086, 2nd row 0 . 1 1 6 , 0.125, 3rd row 0.080, 0.076, long. O e s o phagus 0.605 long, cuticular dilation bearing 13-14 rows body hooks. Deirids 0.36, 0.30; excretory pore 0.30 from anterior end. Nerve ring not seen. Spicules equal, similar 0.570, 0.570 long, about 1/8 b o d y length. Gubernaculum short, simple, subtriangular in ventral view 0.053, 0.050 long. T e n pairs caudal papillae, three pairs ventral and immediately pre-, ad- and post-cloacal respectively, o n e large pair lateral ad-cloacal, two pairs lateral pre-cloacal;
four pairs papillae, pair phasmids well posterior to cloaca near tail tip. Cloacal region with small cuticular b o s s e s ; e a c h large lateral ad-cloacal papilla extending onto small cuticula alae. Tail 0.070, 0.060 long.
F e m a l e ( m e a s u r e m e n t s o f six s p e c i m e n s ) : length o f b o d y 4.7-5.6 ( 5 . 2 ) , m a x i m u m width 0.31 - 0.36 ( 0 . 3 3 ) . C e p h a l i c b u l b 0 . 1 3 5 long b y 0 . 2 3 5 w i d e (w = 1 ) ; c e p h a l i c h o o k s 1st row 0 . 0 7 6 - 0.092 ( 0 . 0 8 4 ) , 2nd row 0.132, 3r d row 0 . 0 7 6 - 0 . 0 9 2 ( 0 . 0 8 1 ) (n = 4 ) long. O e s o phagus 0.61 (n = 1) long, cuticular dilation bearing 14- 15 rows b o d y h o o k s . Deirids 0 . 1 9 - 0 . 3 2 ; excretory pore 0.26 (n = 1) from anterior e n d ; nerve ring not seen.
Vulva 2.4 - 2.7 from anterior end. Vagina 0 . 2 0 (n = 1) long. Tail 0.42 - 0 . 4 8 ( 0 . 4 6 ) long. Eggs not s e e n . T y p e host: Antechinus agilise Dickman, Parnaby, Crow- ther & King, 1 9 9 8 (Dasyuridae: Marsupialia).
Site o f infection: small intestine.
T y p e locality: M o n g a r l o w e River ( 3 5 ° 2 2 ' S, 149° 5 8 ' E ) N e w South Wales, Australia.
Deposition o f types: holotype ( c ) , allotype ( 9 )• Aus
tralian Helminthological Collection, South Australian M u s e u m , Adelaide (Cat. Nos. AHC 3 1 3 3 2 , 3 1 3 3 3 ) ; paratypes Wildlife Collection, CSIRO Wildlife & E c o logy, Canberra, ACT (Cat. No. N 4 5 6 6 ) .
Etymology: the specific n a m e relates to the small size o f the s p e c i e s .
DISCUSSION
A
lthough only a small n u m b e r o f s p e c i m e n s from a single host, s o m e in p o o r condition with d a m a g e d anterior ends, w e r e e x a m i n e d , significant differences b e t w e e n t h e m and o t h e r s p e c i e s o f
Linstowinema c o u l d b e found. L. breve is the smallest s p e c i e s within the g e n u s d e s c r i b e d to date. It is also the only s p e c i e s that has the first and third rows o f cephalic h o o k s o f similar size. In all other species both the first and s e c o n d rows o f c e p h a l i c h o o k s are mar
kedly larger than the third r o w (Smales, 1 9 9 7 , 1 9 9 9 ) . L. breve m o s t closely r e s e m b l e s L. gracile, b o t h s p e cies b e i n g from dasyurids hosts, in having 1 3 - 1 5 rows o f b o d y h o o k s without undulating e d g e s and males having a large pair o f lateral ad-cloacal papillae. In addition to the features d e s c r i b e d a b o v e , L. breve also differs from L. gracile in having a shorter o e s o p h a g u s terminating at the level o f the 5th-7th row o f h o o k s rather than a l o n g e r o e s o p h a g u s terminating at the level o f the m o s t posterior r o w o f b o d y h o o k s . T h e large pair o f lateral ad-cloacal e x t e n d into the lateral alae in L. breve but not L. gracile and L. breve has four pairs o f ventral post cloacal papillae, L. gracile three (Smales, 1999).
O f the other Linstowinema spp. occurring in dasyurids, L. edmondsi further differs from L. breve in having 17- 20 rows o f b o d y h o o k s , the o e s o p h a g u s terminating level with the l l t h - 1 3 t h row and L. rosamondae has 18-19 rows o f b o d y h o o k s , the o e s o p h a g u s termina
ting at t h e level o f the 10th row o f b o d y h o o k s (Smales, 1999).
Seven species o f Linstowinema are found in bandicoots (Peramelidae: Marsupialia) o f w h i c h L. tasmaniense with 12-15 rows o f b o d y h o o k s without undulating e d g e s and a relatively short o e s o p h a g u s is the most similar to L. breve. L. breve can b e distinguished from L. tasmaniense in having the o e s o p h a g u s terminate at the level o f the 5th-7th row o f b o d y h o o k s not the 8th- 10th, four pairs o f post cloacal papillae, not three, and only o n e large pair o f ventral papillae, not three. T h e spicules o f L. breve are 0.57 m m and those o f L. tas
maniense 0 . 8 9 m m long. T h e vagina o f L. breve is 0.20 m m long with the vulva o p e n i n g in the mid b o d y region while L. tasmaniense has a vagina 0 . 1 7 5 m m long and vulva o p e n i n g about V3 from anterior e n d (Smales, 1 9 9 7 ) .
T h e only record o f Linstowinema occuring in A. agilis is o f larval stages (Smales, 1 9 9 9 ) . Since there w e r e n o adult forms present in the s a m e hosts these larvae could not b e identified to species level. It s e e m s likely, however, that they c o u l d have b e e n L. breve.
K E Y TO SPECIES OF THE GENUS LINSTOWINEMA SMALES, 1 9 9 7 (MODIFIED FROM SMALES, 1 9 9 7 )
1. Parasites o f dasyurid marsupials 2 - Parasites o f peramelid marsupials 5 2. 1st row o f c e p h a l i c h o o k s longer than 2 n d row.
O e s o p h a g u s terminates at level o f 11th-13th row o f 1 7 - 2 0 rows o f b o d y h o o k s L. edmondsi - 2nd row o f cephalic hooks longer than 1st row. 3
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3. 1st and 3rd rows o f c e p h a l i c h o o k s o f similar length. O e s o p h a g u s terminates at level o f 5th- 7th r o w o f 1 3 - 1 5 r o w s o f b o d y h o o k s . W i t h cuticular dilation o f o e s o p h a g e a l region. Male with small lateral alae L. breve - 1st row o f c e p h a l i c h o o k s longer than 3rd row.
Without cuticular dilation o f o e s o p h a g e a l region.
Male without lateral alae 4 4. O e s o p h a g u s terminates at level o f 12th-13th row
o f 15 rows o f b o d y h o o k s . N e c k with 16 rows tiny spines L. gracile - O e s o p h a g u s terminates at level o f 10th row o f 1 8 -
19 rows o f b o d y h o o k s . Neck with five rows tiny spines L. rosamundae 5. B o d y h o o k s without undulating e d g e s 6 - B o d y h o o k s with undulating e d g e s 9 6. O e s o p h a g u s terminates posterior to h o o k s o n cuti-
cular dilation o f o e s o p h a g e a l region. Male with four pairs o f papillae, o n e pair o f phasmids o n tail
tip 7 - O e s o p h a g u s terminates at o r anterior to posterior
r o w o f b o d y h o o k s o n cuticular dilation o f o e s o - phageal region. Male with three pairs o f papillae,
o n e pair o f phasmids o n tail tip 8 7. Male with 8-10, female with 10-12 b o d y h o o k s .
Male with six pairs cloacal papillae all s a m e s i z e ; b o d y spines e x t e n d along 9 0 % o f dorsa surface terminate at level o f most anterior pair o f lateral pre-cloacal papillae o n ventral surface ... L. latens - Male with 11-13, female with 12-13 b o d y h o o k s .
Male with six pairs o f cloacal papillae, o n e pair lateral ad-cloacal papillae larger than other five pairs; b o d y spines e x t e n d e d along 7 5 % o f dorsal surface t e r m i n a t e m a r k e d l y a n t e r i o r to cloacal papillae o n ventral surface L. maplestonei 8. Male with ala-like expansions o f body surrounding
c l o a c a ; with six pairs o f cloacal papillae, three pairs o f lateral cloacal papillae larger than three pairs o f ventral cloacal papillae, spicule length about V9 o f b o d y length. F e m a l e with tail longer than 7 0 0 pm L. tasmaniense - Male without ala-like e x p a n s i o n s o f body, with
s e v e n pairs cloacal papillae all s a m e size, spicule length about V] 6 o f b o d y length. F e m a l e with tail shorter than 5 0 0 pm L. peramelis 9. Male with 1 3 - 1 6 , female with 1 4 - 1 8 rows o f b o d y
h o o k s . Male with ala-like e x p a n s i o n s o f b o d y sur- rounding c l o a c a ; b o d y spines terminate at level o f most anterior pair o f lateral pre-cloacal papillae o n ventral surface L. cinctum - Male with 9 - 1 2 , f e m a l e with 1 1 - 1 4 rows o f b o d y
h o o k s . Male without ala-like e x p a n s i o n s o f b o d y surrounding c l o a c a ; b o d y spines terminate mar- kedly anterior to c l o a c a l papillae o n ventral sur-
face 10
10. Male with o e s o p h a g u s shorter than 1,570 pm, female with o e s o p h a g u s shorter than 1,850 pm.
Male with six pairs o f cloacal papillae, pair o f lateral ad-cloacal papillae larger than other five pairs, three pairs o f papillae, o n e pair o f phasmids o n tail tip; spicule length about V1 5 o f b o d y length.
F e m a l e with tail shorter than 9 4 0 p m . . . L. inglisi - Male with oesophagus longer than 1,570 pm, female
with oesophagus longer than 1,860 pm. Male with six pairs o f cloacal papillae all s a m e size, four pairs o f papillae, o n e pair o f phasmids o n tail tip; spi- cule length about V2 0 o f b o d y length. Female with tail longer than 9 8 0 pm L. warringtoni
ACKNOWLEDGEMENTS
I
w o u l d like to thank Dr. David Spratt for providing a c c e s s to the material.REFERENCES
CHABAUD A.G., SEUREAU C , BEVERIDGE I., BAIN O . & DURETTE- DESSET M.C. Sur les nematodes Echinonematinae. Annales de Parasitologic humaine et comparée, 1 9 8 0 , 5 5 , 4 2 7 - 4 4 3 .
SMALES L.R. A revision of the Echinonematinae (Nematoda:
Seuratidae) from bandicoots (Marsupialia: Peramelidae).
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SMALES L.R. Linstowinema Smales, 1 9 9 7 (Nematoda: Seura- tidae) from dasyurids (Marsupialia: Dasyuridae) from Aus- tralia. Systematic Parasitology, 1 9 9 9 , 43, 2 9 - 3 9 .
Reçu le 1 5 juin 1 9 9 9 Accepté le 2 5 août 1 9 9 9
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