six specimens of k. sectatrix ( 2 males with mean weigh of 
 950  50 g , mean body length 376.5  30.4 mm ; 4 females with mean weigh of 868  146 
 g , mean body length 361.2  22.9 mm ) were caught by commercial trawlers in angra dos 
 reis ( 2300 s 4410w ) , rj . fishes were kept in thermal boxes filled with ice prior 
 to being transported to the laboratory and then immediately dissected . both stomach 
 and intestine were removed and examined individually using a stereoscopic 
 microscope . nematodes found were fixed in 95 parts of ethanol 70% , three parts 
 formaldehyde 40% and two parts of glacial acetic acid , cleared in lactophenol and 
 studied and measured using light microscopy . for a detailed study of some 
 structures , samples of eggs were extracted from a dissected uterus of a dissected 
 female and the spicules were obtained from a dissected male . drawings were made 
 using a drawing tube attached to a light microscope olympus bx 51 , magnifications of 
 40x , 100x , 200x , 400x and 1000x . for scanning electron microscopy ( sem ) , specimens were dehydrated in a 
 series of ethanol washes , dried by evaporation with haexamethyldisilazane , coated 
 with gold and scanned in a jeol jsm 6460-lv sem . the identification at the genus 
 level was based on moravec ( 2007 ) and anderson et al . host identification was based on the illustrated key by menezes and figueiredo ( 1985 ) ; nomenclature and 
 classification are updated according to fishbase ( froese & pauly 2012 ) . holotype , allotype and paratypes are deposited in the oswaldo cruz 
 institute helminthological collection ( chioc ) , rj . 1line drawings of pseudascarophis brasiliensis sp . 
 nov . collected from the stomach of kyphosus sectatrix 
 from rio de janeiro , brazil . a : anterior end of male , lateral view ; b : 
 cephalic end of female , apical view ; c : region of vulva , lateral view ; 
 d : fully developed egg ; e : posterior region of female , lateral view ; f : 
 posterior region of male , ventral view ; g : posterior region of male , 
 lateral view ; h : right spicule , ventrolateral view ; i : distal end of 
 left spicule , ventrolateral view . bars = a , c , g : 50 m ; b : 2 m ; d , h , 
 i : 20 m ; e , f : 75 m . 2scanning electron micrographs of pseudascarophis 
 brasiliensis sp . nov . collected from the stomach of 
 kyphosus sectatrix from rio de janeiro , brazil . a : 
 cephalic end , apical view ( a : pseudolabia ; b : tooth - like digitiform 
 process ; c : cephalic papillae ; arrow head : amphid ) ; b : cephalic end , 
 ventrolateral view ( c : cephalic papillae ) ; c : deirid ; d : lateral alae , 
 lateral view ; e : lateral alae , ventral view ; f : posterior end of female , 
 ventrolateral view ( arrow head : phasmid ) ; g : posterior end of male , 
 lateral view ( p : caudal papillae ; lp : lateral caudal papillae ; arrow 
 head : phasmidial papilla ) ; h : area rugosa of male . bars = a , b , c : 2 m ; 
 d : 5 m ; e , g : 20 m ; f , h : 10 m . diagnosis - females larger than males , anterior part of body more 
 slender than posterior part ; cuticle thick and transversely striated . cephalic end 
 rounded in both sexes , four submedian inconspicuous cephalic papillae , visible only 
 by sem ( fig . 2a , b ) and pair of lateral 
 amphids , posterolateral to pseudolabia ( fig . two lateral pseudolabia t - shaped in apical view , emerging 
 externally and somewhat elevated in relation to lateral margins of oral aperture , 
 arching medially to join lateral walls of anterior part of buccal cavity and lacking 
 apical protrusions ( figs 1b , 2a , b ) . four anteriorly directed tooth - like 
 digitiform processes ( 2 subdorsal and 2 subventral ) , emerging sub - marginally from 
 internal surface of oral cavity , not projecting beyond anterior margin of it ( figs 1b , 2a , b ) . deirids bifurcated ( fig . vestibule long , with distinct funnel - shaped prostom 
 visible in lateral view ( fig . nerve - ring 
 encircles muscular oesophagus near its junction with vestibule , excretory pore 
 slightly posterior to nerve ring ( fig . 2d , e ) , extending from level of prostom to that of anterior ends of 
 subventral caudal alae in males and anterior to the level of anus in females . 
 male ( based on holotype and 9 paratypes ) - body 12.8 ( 10.3 - 15.4 ) mm 
 long , maximum width at middle of body 82.5 ( 70 - 100 ) ; width at level of nerve ring 
 42.6 ( 38 - 54 ) , of oesophago - intestinal junction 55.8 ( 41 - 78 ) and of anus 59.6 
 ( 51 - 81 ) . vestibule including prostom 136.4 ( 130 - 145 ) 
 long ; prostom 10 ( 8 - 12 ) long , 10.4 ( 8 - 12 ) wide in lateral view . length of muscular 
 oesophagus 330 ( 290 - 390 ) ; length of glandular oesophagus 5.5 ( 4.3 - 6.6 ) mm ; length 
 ratio of muscular and glandular parts of oesophagus 1:16.6 ( 1 : 14.4 - 21.47 ) ; length 
 of entire oesophagus and vestibule representing 45.5 ( 41 - 50)% of total body length . nerve - ring situated at 163.5 ( 140 - 180 ) from anterior extremity ; deirids and 
 excretory pore at 58 ( 50 - 65 ) and 180 ( 150 - 225 ) , respectively , from anterior end . posterior end of body spirally coiled provided with vesicular caudal alae ( figs 1 g , 2 g ) . pre - anal papillae : three pairs of 
 subventral pedunculate papillae , of which second and third pairs close to each other 
 ( fig . one pair of lateral pedunculate 
 papillae somewhat posterior to cloacal aperture , which may occur at cloacal line . postanal papillae : six pairs present , first four pairs subventral and pedunculate , 
 fourth pair smaller than others , last two pairs sessile near tail tip , located at 
 the same line , in which one is lateral and large and one ventral and very small 
 where phasmidial openings are located ( fig . at least three longitudinal lines of serrate ventral cuticular ridges 
 ( area rugosa ) , anterior to cloaca , about 190 long ( figs 1 g , 2h ) . left spicule 380.6 
 ( 344 - 418 ) long , broad with circular rounded anterior end and somewhat inflated 
 dorsoventrally at distal thin tip ( fig . 1i ) ; 
 its shaft 161 ( 145 - 178 ) long , forming 44.6 ( 2.1 - 46.3 ) % of overall length of spicule 
 ( measured in 3 males ) . right spicule 108.8 ( 100 - 116 ) long , stout with rounded distal 
 end and thin tip ( fig . tail conical , 237 ( 200 - 280 ) long , with rounded tip . female ( based on allotype and 9 paratypes , all gravid ) - body 17.7 
 ( 15.9 - 19.8 ) mm long ; maximum width at middle of body 139.2 ( 100 - 190 ) ; width at level 
 of nerve ring 46.9 ( 41 - 54 ) , of oesophago - intestinal junction 64.7 ( 52 - 80 ) and of 
 anus 66.5 ( 50 - 86 ) . vestibule including prostom , 
 131.2 ( 110 - 143 ) long ; prostom 12 ( 11 - 13 ) long , 10.4 ( 8 - 12 ) wide in lateral view . length of muscular oesophagus 381.7 ( 300 - 465 ) ; length of glandular oesophagus 6.1 
 ( 5.3 - 6.7 ) mm ; length ratio of muscular and glandular parts of oesophagus 1:16.1 
 ( 1:12.8 - 18.9 ) ; length of entire oesophagus and vestibule representing 36.4 ( 33 - 38)% 
 of total body length . deirids , nerve - ring and excretory pore located at 61.2 
 ( 50 - 68 ) , 152.5 ( 130 - 171 ) and 185.1 ( 149 - 220 ) , respectively , from anterior extremity . vulva posterior to middle of body , situated at 11.6 ( 10.9 - 12.3 ) mm from anterior end 
 of body , at 65.8 ( 60.1 - 70.5)% of body length ; vulvar lips not elevated ( fig.1c ) . tail conical , 123.9 ( 110 - 150 ) long , with rounded tip ( figs 1e , 2f ) . phasmidial opening 
 in small lateral papillae about 10 from tail tip ( figs 1e , 2f ) . mature eggs ( containing larvae ) 
 oval , 31.1 ( 30 - 33 ) long and 20.9 ( 20 - 22 ) wide , thick - walled , with smooth surface and 
 distinct polar knobs , one tuff of four thin filaments emerging from each polar knob 
 ( fig . type - locality - angra dos reis ( 2300 s 4410w ) , rj . type data and depository - holotype ( male specimen ) chioc 35848a ; 
 allotype ( female specimen ) chioc 35848b ; paratypes chioc 35849a ( 2 male specimens ) , 
 chioc 35849b ( 2 female specimens ) . host - parasite data - prevalence : four infected fishes of six 
 analysed ; mean intensity of infection : 10  10.8 ( 3 - 26 ) ; mean abundance : 6.7  
 9.8 . etymology - the specific name refers to the country where the 
 specimens were collected . the taxonomy and classification of cystidicolidae has been complex 
 because this group of nematodes exhibit small size ; thus some of their 
 morphologically important features are visible only by sem ( moravec 2007 , moravec & 
 justine 2010 ) . therefore , many of the previous studies lack morphological 
 details and provide inadequate descriptions . cephalic structures are generally 
 considered to be important for the classification of cystidicolidae , although their 
 significance in generic discrimination is still under discussion and more evidence 
 is necessary not only from electron microscopy , but also molecular data ( ferrer et al . 2005 , moravec et al . 2006 , moravec 
 2007 , moravec & gonzlez - sols 
 2007 , moravec & klimpel 2007 , 
 2009 ) . however , there is an increasing 
 consensus in the literature for defining cystidicolid genera based on head 
 morphology . several genera of cystidicolidae ( ascarophis van 
 beneden , caballeronema margolis , capillospirura 
 skryabin , cystidicoloides skinker , pseudascarophis 
 and similascarophis muoz , gonzlez & george - nascimento ) are 
 very similar to each other , with minute differences represented by details of their 
 cephalic structures , which are only visible by sem . moreover , there exist various 
 intermediate features that can be interpreted as interspecific rather than 
 intergeneric differences ( moravec & klimpel 
 2007 ) . indeed , many members of these genera have been reported within 
 ascarophis ( ferrer et al . 2005 ) or transferred to it ( moravec 
 2007 , moravec & gonzlez - sols 
 2007 , moravec & justine 2007 
 ) . in fact , the latter authors have stated that it is apparent from sem studies that 
 the shape and size of pseudolabia , the shape of the mouth and the development of 
 submedian labia ( from well - developed to absent ) may differ among 
 ascarophis species . consequently , ascarophis 
 has been defined as a  catch all  genus , which also includes species with filamented 
 and non - filamented eggs ( ferrer et al . the general morphology of the new species agrees with most diagnostic 
 features described for pseudascarophis , which was erected to 
 accommodate p. kyphosi , a parasite of the congeneric host 
 kyphosus cinerascens ( forskl ) from japan ( ko et al . 1985 ) . indeed , the structure of the 
 mouth is almost identical between both species , indicating that the specimens 
 studied here belong to pseudascarophis , in agreement with ko et al . ( 1985 ) , as well as with the latest 
 review of cystidicolidae provided by moravec 
 ( 2007 ) . the homogeneity of cephalic structures , therefore , confirms the 
 validity of the genus pseudascarophis . the only discrepancies between the new species and the generic diagnosis 
 provided by ko et al . ( 1985 ) are the presence 
 of lateral alae , cephalic papillae ( referred as indistinct in the type species and 
 consequently in the genus ) , three pairs of precloacal and one pair of adcloacal 
 papillae in males ( instead of only 3 pairs of precloacal and none adcloacal 
 papillae ) and the smooth egg shell instead of rugged shell as in p. 
 kyphosi . the presence of four submedian cephalic papillae is a 
 characteristic of spirurine nematodes ( moravec 
 2007 ) and these structures , apparently inconspicuous in p. 
 kyphosi , probably were overlooked by ko et al . the presence of lateral alae is an uncommon feature in 
 cystidicollids , except for two genera , i.e. , ctenascarophis mamaev 
 and metabronema ( taylor ) ( crites et 
 al . apparently , p. kyphosi lacks lateral alae , since 
 these structures were not described by ko et al . however , to be 
 conclusive about the presence or absence of this feature in 
 pseudascarophis , the genus must be reviewed and all previous 
 described species must be better studied , mainly because some of them ( i.e. , 
 p. tropica and p. genypteri ) seem to be 
 misclassified . other differences between the new species and p. kyphosi 
 are based on morphometry . males of both species are similar in size , although the 
 description of p. kyphosi is based on only two specimens . however , 
 the new species has a longer glandular oesophagus ( 4.3 - 6.6 mm vs. 2.9 - 3.0 mm ) , a 
 longer tail ( 200 - 280 vs. 125 - 150 ) , longer spicules ( left 344 - 418 vs. 185 - 210 and 
 right 100 - 116 vs. 80 - 90 ) and , as mentioned above , it has a different pattern of 
 caudal papillae . measurements of p. kyphosi females are also based 
 on only two specimens , who are longer than the new species ( 27.2 - 33.4 mm vs. 
 15.0 - 19.8 mm ) and consequently all other measurements are larger . in addition , some 
 morphometric relationships were different when comparisons were made after 
 calculating some of these from the data provided by ko et al . in fact , the new species has a relatively longer 
 oesophagus ( 32.3 - 38.2% of body length vs. 23.3 - 28.3% ) and tail ( 0.6 - 0.8% of body 
 length vs. 0.4% ) . eggs of both species are similar in length , but those of 
 p. kypsosi are thinner ( 14 - 17 vs. 20 - 22 ) and have more 
 filaments ( at least 6 ) in the tuffs of polar knobs , rather than four as in the new 
 species . at present , two other species have been described in 
 pseudascarophis , namely , p. tropica and 
 p. genypteri ( soloveva 
 1996 , muoz & george - nascimento 
 2001 ) . however , both of them have some features which differs them from 
 the diagnosis of this genus , especially in the morphology of the cephalic end , 
 casting doubts on their generic identity . in fact , the inclusion of p. 
 tropica in pseudascarophis is based on ambiguous 
 diagnostic criteria such as  the structure of head end , digestive system and 
 reproductive system  ( soloveva 1996 ) ; 
 although this species is described as having four teeth - like formations slightly 
 protruded from outside of oral opening , but these structures are not depicted and 
 specimens were not studied by sem . on the other hand , the description of p. 
 tropica suggests various similarities with ascarophis 
 parupenei moravec , orecchia and paggi ( e.g. morphology of cephalic end 
 and posterior end of male , posterior extremity of female with a small appendix and 
 non - filamented eggs ) described from parupeneus indicus ( shaw ) 
 ( mullidae ) ( moravec et al . 1988 ) , congeneric 
 of parupeneus chrysopleuron ( temminck & schlegel ) which is the 
 type host of p. tropica . the other species , p. genypteri , a parasite of 
 genypterus chilensis ( guichenot ) ( ophidiidae ) from chile ( 
 muoz & george - nascimento 2001 ) , was 
 originally assigned to this genus by lacking cephalic papillae , submedial and medial 
 labia , as well as because of the progressive prominence of cuticular striations from 
 anterior to posterior body regions and by having the anterior third of body wider 
 than the posterior region . at specific level , p. genypteri was 
 distinguished from p. kyphosi because it has larger spicules , 
 rounded pseudolabia that join in the middle of the oral opening , eight digitiform 
 buccal processes , unfilamented eggs and four pairs of preanal and five pairs of 
 postanal papillae , the same set of differences allow distinguishing it from the new 
 species . p. genypteri was considered different from 
 ascarophis by two characteristics , i.e. , their pseudolabia 
 appear to be rounded , instead of being conical as in ascarophis and 
 the anterior third is thicker than the rest of the body . n. by owing its ambiguous 
 diagnosis , its similarity with a. parupenei and due to the broader 
 spectrum of morphological features which this genus includes . on the other hand , 
 p. genypteri is provisionally retained in 
 pseudascarophis , based on the criteria of muoz and george - nascimento ( 2001 ) for separating it from 
 ascarophis and by the presence of digitiform buccal processes , 
 until new evidence can help to clarify its generic status .
a new species of pseudascarophis ( nematoda : 
 cystidicolidae ) found in the stomach of kyphosus sectatrix 
 ( linnaeus ) ( kyphosidae ) , off rio de janeiro , brazil , is described . 
 the new 
 species can be differentiated from the other congeners by the presence of 
 lateral alae , distinct but inconspicuous cephalic papillae at the anterior end , 
 three pairs of precloacal and one pair of adcloacal papillae in males , egg 
 morphology and morphometry of glandular oesophagus and spicules . 
 pseudascarophis tropica is transferred to 
 ascarophis as ascarophis tropica 
 ( solov'eva ) comb . 
 n. due to its ambiguous diagnosis .