Excretory Pore Research Articles

Steinernema borjomiense n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from Georgia

Summary A new species of entomopathogenic nematode, Steinernema borjomiense n. sp., was isolated from the body of the host insect, Oryctes nasicornis (Coleoptera: Scarabaeidae), in Georgia, in the territory of Borjomi-Kharagauli. Morphological characters indicate that the new species is closely related to species of the feltiae-group. The infective juveniles are characterised by the following morphological characters: body length of 879 (777-989) μm, distance between the head and excretory pore = 72 (62-80) μm, pharynx length = 132 (122-142) μm, tail length = 70 (60-80) μm, ratio a = 26.3 (23.0-29.3), H% = 45 (40-51), D% = 54 (47-59), E% = 102 (95-115), and lateral fields consisting of seven ridges (eight incisures) at mid-body. Steinernema borjomiense n. sp. was molecularly characterised by sequencing three ribosomal regions (the ITS, the D2-D3 expansion domains and the 18S rRNA gene) and the mitochondrial COI gene. Phylogenetic analyses revealed that S. borjomiense n. sp. differs from all other known species of Steinernema and is a member of the monticolum-group.

Studies on the morphology of Macrolaimus arboreus Truskova & Eroshenko, 1977 (Rhabditida: Chambersiellidae) from Iran

Summary A population of Macrolaimus arboreus was collected from the rhizosphere of pine in Iran. This population of M. arboreus is characterised by the body length, 800-1010 μm in females, lip region with six seta-like papillae directed anteriad, stoma nearly as long as wide (9-11 × 7 μm), with cheilostom slightly longer than gymnostom and cheilorhabdia and gymnorhabdia well-developed, pharyngeal corpus 1.8-2.0 times the isthmus length, with slightly swollen metacorpus, excretory pore located at isthmus level, female reproductive system monodelphic-prodelphic reflexed with short post-vulval uterine sac, female tail conical (57-67 μm, c = 13.7-15.0, c′ = 3.5-3.8), ending in an acute tip which is weakly curved dorsad, and phasmids at 54-60% of tail length. Measurements and illustrations, including SEM, are provided.

Characterisation of the dimorphic Deladenus beddingi n. sp. and its associated woodwasp and fungus

Summary A new dimorphic species of Deladenus isolated from Sirex californicus from Washington, USA, is described as D. beddingi n. sp. Evolutionary relationships of the new species with other Deladenus species were assessed using multilocus sequencing. Phylogenetic relationships derived from analyses of mtCO1 and ITS showed D. beddingi n. sp. to be genetically distinct from other North American Deladenus parasitising Sirex. Molecular analyses indicated that D. beddingi n. sp. is a member of the D. siricidicola species complex, which also includes undescribed native Deladenus from Sirex cyaneus and S. nitidus, and D. siricidicola from S. noctilio. Mycophagous adults were characterised by the position of the excretory pore, which was located 32 (22-52) and 48 (38-69) μm anterior to the hemizonid in mycophagous females and males, respectively. Typologically, the new species is most similar to D. siricidicola, D. proximus and D. nitobei, but can be distinguished from these species by several morphometric traits, including the value of ratios a, b, c of the mycophagous females and males, ratio b of the infective females, and the morphology of the tail of the mycophagous females, which is narrow and gradually tapering. This novel nematode species feeds on the fungus Amylostereum chailletii during its mycophagous phase. Experimental results showed very little reproduction by D. beddingi n. sp. when feeding on A. areolatum compared to robust reproduction when feeding on A. chailletii.

Morphological and molecular characterisation of Hemicriconemoides paracamelliae sp. n. (Nematoda: Criconematidae) and two known species of Hemicriconemoides from China

Summary Sheathoid nematodes of the genus Hemicriconemoides are migratory root-ectoparasites of many crops but damage is documented for only a few species. Hemicriconemoides paracamelliae sp. n., isolated in Hangzhou, Zhejiang, China, from the rhizosphere of Cinninghamia lanceolata, is described together with H. kanayaensis and H. parataiwanensis. These three species are characterised morphologically and molecularly with important morphological details elucidated by SEM photographs. The new species can be characterised by the en face view having a dorsoventrally orientated oral disc with slit-like opening, and the labial plate being composed of two lateral semi-globular shaped projections on the lateral sides of the oral disc. This new species has the first lip annulus expanded and slightly wider than the second, stylet 83 (80-85) μm long, excretory pore located 5-6 annuli posterior to the base of the pharyngeal bulb, vulva slit-like, vulval flaps absent, spermatheca rounded to oblong-shaped, and anus located 5-8 annuli posterior to vulva. The tail is elongated, conoid, with the terminal annuli curving dorsally or ventrally to form a finely rounded tip. The study provides the first record of H. kanayaensis from mainland China, a new host association of H. parataiwanensis, and molecular sequencing data of the 18S, 28S D2-D3 and ITS sequences.

Description of Gracilacus paralatescens n. sp. (Nematoda:Paratylenchinae) found from the rhizosphere of Bamboo in Zhejiang, China.

Abstract Gracilacus paralatescens n. sp., isolated in Anji County, Zhejiang Province, China from the rhizospheric soil of bamboo. The new species can be characterized by the female lateral field with three incisures, stylet 71.5 to 78.8 µm long, lip region truncated, excretory pore located anterior to basal knobs. Vulval lips non-protruding and without vulval flap, spermatheca large, elongated squarish shaped filled with sperms. Tail slender, relatively straight having wedge shape terminus. The spicule slender, slightly curved and 17.5 to 18.9 µm long. In the phylogenetic analysis based on 18S, D2-D3 of 28S and ITS regions of rDNA, the new species is clustered with Paratylenchid species having longer stylet length. Morphologically, the new species belongs to Group 9 of Paratylenchus sensu lato and is most similar to G. latescens.

Bursaphelenchus geraerti n. sp. (Tylenchina: Aphelenchoididae) found in packaging wood from the United Arab Emirates

SummaryBursaphelenchus geraertin. sp., isolated in Tianjin, P.R. China, from packaging wood made ofPinussp. imported from the United Arab Emirates, is described. It is characterised by the lateral field with three lines, a stylet 13-14 μm long with small basal swellings, excretory pore located posterior to nerve ring, spicule mitten-shaped, ventrally arcuate with lamina smoothly tapering towards distal tip, with a distinct bend near 60% of total length, condylus elongated with rounded tip, rostrum conical with finely rounded tip, and cucullus weakly developed or absent. The bursal flap is wide and spade-like with the posterior margin truncate or rounded and starts posterior to P6 gland papillae. A vulval flap is absent and the tail is conical, strongly ventrally curved with the terminus pointed and sometimes appearing as a mucron. The new species is characterised by morphological and molecular analysis and is close toB. decraemerae,B. gerberaeandB. sakishimanus.

Delatylus andersoni n. gen., n. sp. (Nematoda: Neotylenchidae) Isolated from White Pine (Pinus monticola) Lumber from USA and Intercepted in Ningbo, China.

Three populations of neotylenchid nematodes were isolated in Ningbo, P. R. China, from white pine lumber (Pinus monticola) imported from the USA. The nematodes were morphologically intermediate between Hexatylus and Deladenus. The nematodes were molecularly characterized based on sequences of the rDNA small subunit 18S, large subunit 28S D2/D3, and internal transcribed spacer sequences. The phylogenetic inferences placed the nematodes with other neotylenchid nematodes, i.e., Fergusobia and Rubzovinema. Based on the morphology and phylogenetic analysis, this nematode is described herein as Delatylus andersoni n. gen., n. sp. The new genus/species is characterized by the female body habitus ranging from nonobese to semiobese and from straight to dorsally curved when heat relaxed, cephalic framework with six unequal sized lip sectors, lateral fields having 10 to 12 lines, 4 to 5 guide rings on the stylet, excretory pore posterior to the nerve ring, spermatheca diminished or absent, vulvar opening large, and relative proximity of vulva to the anus. Detailed morphological and molecular characterization of the new genus/species is presented along with the comparison of the related genera.

Molecular and morphological characterisation of Aphelenchoides kheirii n. sp. (Nematoda: Aphelenchoididae) isolated from Pinus nigra in north-western Iran

SummaryAphelenchoides kheiriin. sp. was isolated during a survey of nematodes associated with bark samples of pine trees (Pinus nigra) in West Azerbaijan province, north-western Iran. The new species has a body length of 500 (448-520) μm in the female and 442 (402-480) μm in the male. The cuticle is weakly annulated with four lateral lines and the lip region is offset. The stylet is 10.4 (10-11) μm long with small basal swellings and the excretory pore located immediately posterior to base of metacorpus; hemizonid invisible. The post-vulval uterine sac length 37.7 (28-45) μm. Spicules are relatively short (18-20 μm in dorsal limb) and the end of the dorsal limb clearly curved ventrally like a hook. The male tail has usual three pairs of caudal papillae (2 + 2 + 2) and a well-developed mucron. The female tail is conical, terminating in a complicated step-like projection, usually with many tiny nodular protuberances. The new species belongs to the Group 2 category ofAphelenchoidesspeciessensuShahina in which ten known species among Groups 2 and 4sensuShahina, namely:A. arcticus,A. blastophthorus,A. fuchsi,A. parasaprophilus,A. paraxui,A. xui,A. dactylocercus,A. gynotylurus,A. iranicusandA. saprophilusare the most similar species. Phylogenetic analysis based on small subunit (SSU) and partial large subunit (LSU) sequences of rRNA supported the morphological results.

Bursaphelenchus moensi n. sp. (Tylenchina: Aphelenchoididae) found in packaging wood from the USA

Bursaphelenchusmoensin. sp., isolated in Tianjin Port, China, fromPinuspackaging wood imported from the USA, is described. It is characterised by a lateral field with three lines (two bands), stylet 13.0-14.9μm long, excretory pore situated at same level as, or slightly posterior to, the nerve ring, spicules 13.0-15.5μm long, mitten-shaped, condylus high and broad with squared, rounded or pointed end, rostrum triangular or conical with bluntly rounded tip, and cucullus absent, bursa small, starting posterior to P4, narrow oblong to irregular in shape and with an oval central projection, female vulval flap absent, and tail conical with a finely rounded or mucronate terminus. The new species belongs to thehofmanni-group and is most similar toB. paraparvispicularis,B. parvispicularisandB. wuae. It is distinguished from closely related species by morphology, ITS-RFLP patterns and partial 18S, ITS and 28S D2-D3 rDNA gene sequencing results.

Morphological and molecular characterisation of Aphelenchoides primadentus n. sp. (Nematoda: Aphelenchoididae) from northern Iran

Aphelenchoides primadentusn. sp. is described and illustrated based on its morphological, morphometric and molecular characters. It was recovered from natural forests of northern Iran in association with mosses. The new species is characterised by its body length of 502-613μm in females and 461-564μm in males, presence of three lines in the lateral fields, a low lip region slightly offset by a shallow depression, 11.1-13.8μm long stylet in females, its conus being longer than the shaft (m = 53.0-68.5) and bearing well-developed, rounded basal knobs, the excretory pore located atcaone body diam. posterior to the metacorpus, a conical tail with a multipapillate terminus or with a single, warty, wide mucron-like structure at the tip, and males with 19-22μm long arcuate spicules that lack a well-developed condylus and rostrum. The new species was morphologically compared with species of the genus having three lines in the lateral field and a multipapillate tail tip or tail with warty mucron, namelyA. iranicusandA. heidelbergi. Compared toA. ensete,A. huntensisandA. gorganensis, three species with a multipapillate tail tip or warty mucron at the tail tip, the new species has a basic difference in the number of lines in the lateral field and, compared to two species,A. composticolaandA. petersi, which have three lines in the lateral field and a similar overall morphology, the new species has basic differences in tail tip morphology. The results of phylogenetic analyses using partial sequences of ribosomal small subunit RNA (SSU) and mitochondrial cytochrome c oxidase 1 (COImtDNA) genes revealed there is currently no sequenced species of the genus phylogenetically close to the new species being sequenced for these two genomic and non-genomic regions. The new species forms a clade withA. ritzemabosiin SSU, and three other species,A. besseyi,A. ritzemabosiandA. fujianensis, in theCOItree.

Bursaphelenchus decraemerae n. sp. (Tylenchina: Aphelenchoididae) found in packaging wood from the USA

Bursaphelenchus decraemeraen. sp., isolated in Ningbo, China, from packaging wood made ofPinussp. imported from the USA, is described. It is characterised by the lateral field with three lines, a stylet 10-12 μm long with small basal swellings, excretory pore located 4-12 μm posterior to median bulb, spicule small, ventrally arcuate with lamina gradually tapering to distal tip, rostrum triangular pointed to conical, condylus elongated with bluntly rounded tip, and cucullus minute, barely visible. There are seven caudal papillae arranged as a single ventral precloacal papilla, one adcloacal pair and two postcloacal pairs. The bursal flap is narrow and oval. A small vulval flap is present in lateral view of the female and the tail is conical, strongly ventrally curved with the terminus finely pointed and sometimes appearing like a mucron. The new species is characterised by morphological and molecular analysis and is close toB. gerberaeandB. sakishimanus.

Belgopeltula belgica (Vincx & Gourbault, 1992) gen. et comb. nov. and Mudwigglus micramphidium sp. nov. from the west coast of Sweden, and reappraisal of the genus Pseudaraeolaimus Chitwood, 1951 (Nematoda: Araeolaimida: Diplopeltidae)

Two species of the nematode family Diplopeltidae are described from Skagerrak. The new genus Belgopeltula gen. nov. is proposed for Diplopeltula belgica Vincx & Gourbault, 1992 and is characterised by: amphidial fovea circular in female and double-loop-shaped in male; excretory pore located at the level of cephalic setae bases; oral opening on the dorsal side of the body; pharynx subdivided into strongly muscularised fusiform corpus and weakly muscularised narrow and long postcorpus; female didelphic with antidromously reflexed ovaries; supplements absent. Mudwigglus micramphidium sp. nov. is characterised by: a body of 0.6 mm long; cephalic sensilla 1.5 µm long; amphidial fovea loop-shaped, 8 µm long and 3.5 µm wide; gymnostom without cuticularised ring; tail elongate conoid, with subcylindrical distal part; terminal setae absent; spicules 15 µm long; gubernaculum present; two midventral precloacal setae. It is distinguished from M. macramphidium Leduc, 2013 in having shorter amphidial fovea, shorter spicules and presence of two precloacal setae. Redescription of Diplopeltis cylindricauda Allgén, 1932 is provided based on type material. Diplopeltula minuta Vitiello, 1972 is transferred to the genus Mudwigglus Leduc, 2013. Diplopeltis cylindricauda Allgén, 1932, Diplopeltula laminata Vitiello, 1972 and Diplopeltula cassidaignensis Vitiello, 1972 are transferred to the genus Pseudaraeolaimus Chitwood, 1951.

Description of Pristionchus stercoraris sp. n. and first report of Tylopharynx foetida from India (Nematoda: Diplogastrina)

Pristionchus stercoraris sp. n. and Tylopharynx foetida (Butschli, 1874) Goffart, 1930 of the suborder Diplogastrina are described and illustrated in detail. Both the species were isolated from farmyard manure collected from Baramulla, Jammu & Kashmir, India. P. stercoraris sp. n. is characterized by faint annulations on cuticle, steno– as well as eurystomatous types of stoma, thin-walled cheilostom, long elongate cardia, slender spicules with slightly anteriorly curved distal tip, a boat-shaped gubernaculum with a medial dorsal convex; proximally with an anteriorly directed needle-like extension and distally with a sleeve and eight pairs of genital papillae. Measurements and descriptions of our specimens of T. foetida agree well with that of Butschli (1874). However, slight differences were observed in the length of stoma, tail, anal body diameter, anterior pharynx, and in the position of excretory pore. No species of both Pristionchus and Tylopharynx have so far been reported from India.

Some nematodes from freshwater fishes in central Africa.

Twenty species (sixteen adult and four larval) of parasitic nematodes belonging to the Ascaridoidea, Camallanoidea, Cosmocercoidea, Dioctophymatoidea, Habronematoidea, Oxyuroidea, Seuratoidea, and Thelazioidea were collected from freshwater fishes of the Congo River basin in the Democratic Republic of the Congo and the Central African Republic in 2008 and 2012, respectively. Based on light and scanning electron microscopical examination, many species are redescribed in detail. This material also contained four previously unknown species, Labeonema longispiculatum sp. n. from Synodontis acanthomias Boulenger, Gendria longispiculata sp. n. from Schilbe grenfelli (Boulenger), G. sanghaensis sp. n. from Schilbe marmoratus Boulenger, and Cucullanus congolensis sp. n. from Auchenoglanis occidentalis (Valenciennes). The new species L. longispiculatum is mainly characterised by conspicuously long (210-228 µm) spicules, approximately twice as long as those in other congeners, the length (45-48 µm) of the gubernaculum and the host family (Mochokidae), whereas G. longispiculata by very long (1.2 mm) spicules, the shape of the oesophagus and cephalic vesicle, distribution of postanal papillae and the host family (Schilbeidae). Main characteristic features of G. sanghaensis are the presence of a hexagonal oral aperture surrounded by lip-like structures, the posterior portion of the oesophagus moderately expanded, spicules and the gubernaculum 414-438 µm and 54-57 µm long, respectively, deirids located at the level of the posterior end of the oesophagus and the absence of cervical alae. Cucullanus congolensis differs from congeneric species parasitising African freshwater and brackish-water fishes mainly in the absence of a ventral precloacal sucker and lateral preanal papillae, the presence of a large median precloacal papilla-like formation, spicules 480-489 µm long and the location of the excretory pore in the region of the oesophago-intestinal junction. Chabaudus Inglis et Ogden, 1965 is considered a junior synonym of Gendria Baylis, 1930 and, consequently, species listed in the former genus are transferred to the latter as G. alaini (Alfonso-Roque, 1981) comb. n., G. chabaudi (Inglis et Ogden, 1965) comb. n., G. dehradunensis (Rizvi, Bursey et Maity, 2016) comb. n., G. thysi (Puylaert, 1970) comb. n. and G. williamsi (Puylaert, 1970) comb. n. The findings represent many new host and geographical records.

Gnathostomatidae nematode parasite of Colomesus psittacus (Osteichthyes, Tetraodontiformes) in the Ilha de Marajó, Brazilian Amazon.

The genus Gnathostoma comprises 17 species, whose adult specimens are found in the stomach serosa of animals that consume raw fish; some species of the genus are zoonotic agents. The present study describes the presence of a nematode (Gnathostomatidae) parasitizing the digestive tract of Colomesus psittacus in the Ilha de Marajó in the eastern Brazilian Amazon. Thirty specimens of C. psittacus were collected in the municipality of Soure, Ilha de Marajó, state of Pará, Brazil, transported to the laboratory, necropsied and the helminths were collected and fixed. Of the 30 fish that were studied, 16.67% were parasitized with nematodes. The nematode larvae found encysted in the intestinal serosa have anterior region with two lips, each with a pair of papillae; a cephalic bulb armed with six rows of discontinuous spines; four cervical sacs; a claviform esophagus; cuticular striations along the body; a simple excretory pore; and a short tail ending in a mucron. These morphological structures are diagnostic characters of the genus Gnathostoma, whose adults parasitize the stomach of carnivorous mammals and, rarely, the stomach of fish. However, fish, amphibians, reptiles, and birds are intermediate hosts of the third-stage larvae (L3), and humans may act as accidental hosts.

A scanning electron microscopy study of early development in vitro of Contracaecum multipapillatum s.l. (Nematoda: Anisakidae) from a brown pelican (Pelecanus occidentalis) from the Gulf of California, Mexico.

Eggs obtained from the uteri of female nematodes, genetically identified as Contracaecum multipapillatum s.l., found in a brown pelican (Pelecanus occidentalis) from Bahía de La Paz, Gulf of California, Mexico, were used to study the early developmental stages of this anisakid by scanning electron microscopy (SEM). Egg dimensions were approximately 54×45μm measured by SEM. Observation of the eggs revealed an outer surface of fibrous appearance. The newly hatched larvae were ensheathed and highly motile. Observation with SEM showed that the sheaths of the larvae were striated and revealed an excretory pore and a cleft near the anterior end of the sheath, presumably to facilitate the opening of the sheath for the emergence of the larva. The hatched larvae were placed in nutritive culture medium, where they grew within their sheath, some exsheathing completely 2weeks later. The surface patterns of the sheath and the cuticle of the exsheathed larvae were clearly different. Although they did not moult during culture, SEM revealed a morphology typical of third-stage larvae of Contracaecum from fish, as previously observed by optical microscopy. Thus, we suggest that newly hatched larvae from eggs of C. multipapillatum are third larval stage but with sheath of the second larval stage, as occuring in other anisakids.

Morphological and molecular characterization of Tarantobelus arachnicida gen. n., sp. n. (Nematoda, Rhabditida, Brevibuccidae), a parasitic nematode of tarantulas.

A new genus and new species, Tarantobelus arachnicida, was found in the oral opening of tarantula spiders bred in captivity in Poland. The new species is characterized by having a small body (0.77-0.95 mm long in females and 0.66-0.84 mm in males), cuticle poorly annulated by transverse incisures, lateral field inconspicuous, lips separated with small cuticular flaps topping each lip, stoma panagrolaimoid with gymnostom well developed with robust and refringent rhabdia, pharynx panagrolaimoid with isthmus slightly longer than the basal bulb, intestine with cardiac (anterior) and rectal (posterior) areas with narrower walls. Mature females with intestinal cells including needle crystal packs, excretory pore at isthmus level, female reproductive system panagrolaimoid with post-vulval sac 0.4-0.8 times the length of the corresponding body diameter and having very thick walls, vulva very prominent, female rectum 0.8-1.3 times the length of the anal body diameter, female tail conical with acute tip with phasmids at 58-62% of its length. Male tail conical with long and thin mucro, spicules ventrad bent having rounded manubrium and thick gubernaculum. Description, measurements and illustrations of the new species are provided. Molecular analyses show its relationship with Brevibucca and Cuticonema. On the other hand, Medibulla and its corresponding subfamily Medibullinae, previously in Osstellidae, are transferred to Panagrolaimidae, being Shahnematinae, the junior synonym of Medibullinae. Indocephalobus, recently proposed and located in the family Panagrolaimidae, is considered a junior synonym of Diplogastrellus (Diplogasteromorpha), and its only species, I. zebrae, is considered a junior synonym of D. gracilis. In addition, a key to identification of panagrolaimoid genera is included.

Morphology and Phylogeny of Two Novel Ciliates, Arcanisutura chongmingensis n. gen., n. sp. and Naxella paralucida n. sp. from Shanghai, China.

The morphologies of two novel ciliates, Arcanisutura chongmingensis n. gen., n. sp. and Naxella paralucida n. sp., collected from Shanghai, China, have been investigated using live observation and silver staining methods. Arcanisutura n. gen. can be easily distinguished from related genera by its inconspicuous, oblique anterior suture. Arcanisutura chongmingensis n. sp. is mainly recognized by its elongated body with a tail-like posterior end, 25-33 somatic kineties, and 4-11 excretory pores. Naxella paralucida n. sp. can be distinguished from its congeners based on its two short nassulid organelles, fusiform trichocysts, 37-49 somatic kineties, and 16 nematodesmal rods. The small-subunit (SSU) rRNA gene sequences of these two species are presented, revealing the phylogenetic positions of Arcanisutura and Naxella. Phylogenetic analyses show that Arcanisutura forms a sister clade to other synhymeniid genera, namely, Chilodontopsis, Orthodonella, and Zosterodasys; Naxella is most closely related to Nassula spp. and is located within the monophyletic clade of the family Nassulidae.

Redescription and first genetic characterisation of Procamallanus (Spirocamallanus) macaensis Vicente & Santos, 1972 (Nematoda: Camallanidae), including re-evaluation of the species of Procamallanus (Spirocamallanus) from marine fishes off Brazil.

Newly collected specimens of Procamallanus (Spirocamallanus) macaensis Vicente & Santos, 1972 from the intestine of Paralonchurus brasiliensis (Steindachner), off Rio de Janeiro, Brazil, are redescribed and genetically characterised. Additionally, all congeners deposited in the Coleção Helmintológica do Instituto Oswaldo Cruz (CHIOC) parasitic in marine fishes of the South Atlantic, including types of P. (S.) macaensis, were re-evaluated. The following features are described for the first time in P. (S.) macaensis: morphology and arrangement of cephalic structures, shape of deirids and location of phasmids. The position of the excretory pore, the number and arrangement of caudal papillae in males, the structure of the spicules and of tail end in both males and females are rectified. Most specimens deposited in the CHIOC identified as P. (S.) pereirai Annereaux, 1946 were transferred to P. (S.) macaensis and others were designated as Procamallanus (S.) sp. Procamallanus (S.) cruzi Guimarães, Cristófaro & Rodrigues, 1976 is considered a species inquirenda due to its poor description and the lack of match of its original description with the type-material re-examined. Moreover, several taxonomic problems were noted after observations of the specimens (mostly poorly preserved), including inadequate morphological reports as well as misidentifications. Phylogenies inferred using sequences of the SSU rDNA from camallanids (Nematoda: Camallanidae) mostly generated weakly supported clades; however, Camallanus Railliet & Henry, 1915 and Procamallanus Baylis, 1923 do not seem to be monophyletic. Based on the present results and the lack of molecular data, it would be pertinent to adopt the widely-used classification for the subgenera of Procamallanus.

Spinitectus aguapeiensis n. sp. (Nematoda: Cystidicolidae) from Pimelodella avanhandavae Eigenmann (Siluriformes: Heptapteridae) in the River Aguapeí, Upper Paraná River Basin, Brazil.

Nematodes belonging to Spinitectus Fourment, 1883 (Nematoda: Cystidicolidae) were found in the intestine of Pimelodella avanhandavae Eigenmann (Siluriformes: Heptapteridae) from the Aguapeí River, Brazil. They represent a new species, Spinitectus aguapeiensis n. sp., which differs morphologically from its congeners in the body length, the number of spinose rings, the location of the excretory pore, the number of precloacal papillae and the length of the spicules. The new species is the first South American species within the genus with a remarkably spirally coiled posterior extremity in males and the largest spicules. It is also the second species with the highest number of precloacal papillae and has unique shape of the small spicule. Spinitectus aguapeiensis n. sp. is the first helminth species found in P. avanhandavae, the fourth species of this genus recorded in the River Paraná Basin and the sixth species of Spinitectus in South America.