First report of a gryporhynchid tapeworm (Cestoda: Cyclophyllidea) from New Zealand and from an eleotrid fish, described from metacestodes and in vitro-grown worms

2011 ◽  
Vol 86 (4) ◽  
pp. 453-464 ◽  
Author(s):  
B. Presswell ◽  
R. Poulin ◽  
H.S. Randhawa
Keyword(s):  
New Zealand ◽  
First Record ◽  
Small Subunit ◽  
Body Cavity ◽  
The Body ◽  
Species Determination ◽  
Fish Family ◽  
Rdna Sequences ◽  
Stage Of Development

AbstractMetacestodes are often found in the body cavity of the common bully (Gobiomorphus cotidianus McDowall), from freshwater habitats in Otago, New Zealand. Identification of metacestodes relies only on the number, size and shape of the rostellar hooks. To attempt species determination, we cultivated metacestodes in vitro for up to 23 days, during which they matured to at least the male stage of development, although female organs were not discernable. Identified as members of the genus Paradilepis Hsü, 1935 (family Gryporhynchidae), these specimens are compared to previously described species, in particular P. minima (Goss, 1940), from Australia, the closest species, both geographically and morphologically. Although the size of scolex, suckers and proglottids differ significantly from those of P. minima, we are cautious about interpreting ‘adults’ grown in vitro, because we are unsure whether the artificial conditions alter development. For this reason, and because of the lack of female organs, we refrain from erecting a new species, and refer to the specimens as Paradilepis cf. minima until such time as the adults are found in the definitive host. With this proviso we present here a description of the in vitro-grown worms and the metacestodes as a preliminary study of this cestode. A molecular analysis of small subunit (SSU) rDNA sequences, shows the position of P. cf. minima and another gryporhynchid, Neogryporhynchus cheilancristrotus (Wedl, 1855), to be equivocal, but confirms their exclusion from the Dilepididae and Hymenolepididae. This is the first record of a gryporhynchid from New Zealand, and the first from the fish family Eleotridae.

scholarly journals Studies on the Life Cycle of Some New Zealand Anisakidae (Nematoda)

2021 ◽  
Author(s):  
◽  
Rosemary Jennifer Hurst
Keyword(s):  
Life Cycle ◽  
New Zealand ◽  
Body Cavity ◽  
The Body ◽  
In Vitro Cultivation ◽  
Free Living ◽  
Larval Stages ◽  
Factors Influencing ◽  
Phocarctos Hookeri

<p>The life cycle of Anisakis simplex in New Zealand waters is described from observations on the morphology, distribution and behaviour of free-living and parasitic stages. Comparison with the life cyles of two other anisakids, Phocanema decipiens Myers 1959 and Thynnascaris adunca Rudolphi 1802 shows differences in distribution, degrees of host specificity, the status of invertebrate hosts, the factors influencing infestation levels of teleost hosts, and the location and pathological effects of infestation. Larval stages occurring in intermediate and paratenic hosts were identified by comparison of larval and adult morphometrics. A. simplex larvae were also positively identified by in vitro cultivation through to adults. Some morphometric variations compared to overseas descriptions are apparent. The ventriculus of A. simplex larvae is shorter relative to body length and the intestinal caecum of P. decipiens is longer relative to ventriculus length. Egg and free-living larval stages were obtained from in vitro cultivation of (A. simplex) and collection of eggs from mature adults from definitive hosts (T. adunca). Eggs of P. decipiens were not obtained. Eggs of A. simplex and T. adunca hatch in 8-11 days at 15 [degrees] C. A. simplex eggs hatch in 6 days at a temperature of 22 [degrees] C and did not hatch in 16 days at 10 [degrees] C. Eggs and free-living stage III larvae of A. simplex and T. adunca are similar in morphology with little differentiation of internal structures. Examination of the stomach contents of pelagic fish infested with anisakids indicated that possible intermediate hosts of A. simplex are the euphausiid Nyctiphanes australis and the decapod Munida gregaria. Possible hosts of T. adunca and M. gregaria are a wide variety of smaller zooplanktonic groups, e.g. decapod larvae and copepods. Larvae of A. simplex were found in one of 8850 N. australis; larvae of T. adunca were found in 69 of 3999 chaetognaths (Sagitta spp.) a medusa and a decapod larva. These larvae are morphologically similar to Stage III larvae from teleosts. No anisakids were found in 3956 Euphausia spp., 1147 M. gregaria and 740 prawns. Twenty five T. adunca larvae and adults were found in 818 freshly eaten M. gregaria in teleost stomachs, indicating that this invertebrate may act as a paratenic and a definitive host. Experimental infection of N. australis and M. gregaria with stage II larvae of A. simplex and T. adunca was unsuccessful. The location of anisakid infestation in three pelagic teleost species, Thyrsites atun, Trachurus novaezelandiae and Trachurus declivis is described. A. simplex larvae are found mainly in the body cavity of all species, at the posterior end of the stomach, with less than one percent occurring in the musculature. Distribution of A. simplex larvae does not change with increasing size of the host or increasing total worm burden. Thyrsites atun have a higher proportion of larvae in the stomach wall (8-13%) compared to Trachurus spp. (< 4%). T. adunca larvae are found infrequently in the body cavity of all three species, on the pyloric caeca and in the stomach wall. Adults and larvae of T. adunca are found more commonly in the alimentary canal, indicating that these teleosts are more important as definitive hosts in the life cycle of this anisakid. P. decipiens larvae are found only in Thyrsites atun and occur mainly in the muscles (98.5%). No quantitative pathogenic effects of anisakid infestation on these teleosts hosts were detected. The main factors influencing the infestation of the three teleost species are age of the host, locality and season. Sex of the host and depth (over the continental shelf, 0-250 m) are not important. A. simplex infestation increased with age in all host species examined, and was higher in Trachurus declivis from the southern-most locality, suggesting the existence of at least two distinct populations of this species. Significant differences in infestation of Thyrsites atun with P. decipiens suggests that this anisakid may be more common in southern localities also. The infestation of Thyrsites atun by larval and adult T. adunca in the alimentary canal is most influenced by season and closely related to diet. Nematode samples were obtained from the marine mammals Arctocephalus forsteri, Kogia breviceps and Phocarctos hookeri. Adult A. simplex were recorded from A. forsteri (a new host record) and Kogia breviceps; preadults from Phocarctos hookeri. Adult P. decipiens were recorded from Phocarctos hookeri; preadults from Arctocephalus forsteri and K. breviceps. Other anisakids found were Anisakis physeteris (Baylis 1923), Contracaecum osculatum Rudolphi 1802 and Pseudoterranova kogiae (Johnston and Mawson 1939) Mosgovoi 1951. These records are all new for the New Zealand region except P. decipiens from P. hookeri and C. osculatum from Arctocephalus forsteri. A. simplex and C. osculatum were found associated with gastric ulcers in Arctocephalus forsteri.</p>

scholarly journals Studies on the Life Cycle of Some New Zealand Anisakidae (Nematoda)

2021 ◽  
Author(s):  
◽  
Rosemary Jennifer Hurst
Keyword(s):  
Life Cycle ◽  
New Zealand ◽  
Body Cavity ◽  
The Body ◽  
In Vitro Cultivation ◽  
Free Living ◽  
Larval Stages ◽  
Factors Influencing ◽  
Phocarctos Hookeri

<p>The life cycle of Anisakis simplex in New Zealand waters is described from observations on the morphology, distribution and behaviour of free-living and parasitic stages. Comparison with the life cyles of two other anisakids, Phocanema decipiens Myers 1959 and Thynnascaris adunca Rudolphi 1802 shows differences in distribution, degrees of host specificity, the status of invertebrate hosts, the factors influencing infestation levels of teleost hosts, and the location and pathological effects of infestation. Larval stages occurring in intermediate and paratenic hosts were identified by comparison of larval and adult morphometrics. A. simplex larvae were also positively identified by in vitro cultivation through to adults. Some morphometric variations compared to overseas descriptions are apparent. The ventriculus of A. simplex larvae is shorter relative to body length and the intestinal caecum of P. decipiens is longer relative to ventriculus length. Egg and free-living larval stages were obtained from in vitro cultivation of (A. simplex) and collection of eggs from mature adults from definitive hosts (T. adunca). Eggs of P. decipiens were not obtained. Eggs of A. simplex and T. adunca hatch in 8-11 days at 15 [degrees] C. A. simplex eggs hatch in 6 days at a temperature of 22 [degrees] C and did not hatch in 16 days at 10 [degrees] C. Eggs and free-living stage III larvae of A. simplex and T. adunca are similar in morphology with little differentiation of internal structures. Examination of the stomach contents of pelagic fish infested with anisakids indicated that possible intermediate hosts of A. simplex are the euphausiid Nyctiphanes australis and the decapod Munida gregaria. Possible hosts of T. adunca and M. gregaria are a wide variety of smaller zooplanktonic groups, e.g. decapod larvae and copepods. Larvae of A. simplex were found in one of 8850 N. australis; larvae of T. adunca were found in 69 of 3999 chaetognaths (Sagitta spp.) a medusa and a decapod larva. These larvae are morphologically similar to Stage III larvae from teleosts. No anisakids were found in 3956 Euphausia spp., 1147 M. gregaria and 740 prawns. Twenty five T. adunca larvae and adults were found in 818 freshly eaten M. gregaria in teleost stomachs, indicating that this invertebrate may act as a paratenic and a definitive host. Experimental infection of N. australis and M. gregaria with stage II larvae of A. simplex and T. adunca was unsuccessful. The location of anisakid infestation in three pelagic teleost species, Thyrsites atun, Trachurus novaezelandiae and Trachurus declivis is described. A. simplex larvae are found mainly in the body cavity of all species, at the posterior end of the stomach, with less than one percent occurring in the musculature. Distribution of A. simplex larvae does not change with increasing size of the host or increasing total worm burden. Thyrsites atun have a higher proportion of larvae in the stomach wall (8-13%) compared to Trachurus spp. (< 4%). T. adunca larvae are found infrequently in the body cavity of all three species, on the pyloric caeca and in the stomach wall. Adults and larvae of T. adunca are found more commonly in the alimentary canal, indicating that these teleosts are more important as definitive hosts in the life cycle of this anisakid. P. decipiens larvae are found only in Thyrsites atun and occur mainly in the muscles (98.5%). No quantitative pathogenic effects of anisakid infestation on these teleosts hosts were detected. The main factors influencing the infestation of the three teleost species are age of the host, locality and season. Sex of the host and depth (over the continental shelf, 0-250 m) are not important. A. simplex infestation increased with age in all host species examined, and was higher in Trachurus declivis from the southern-most locality, suggesting the existence of at least two distinct populations of this species. Significant differences in infestation of Thyrsites atun with P. decipiens suggests that this anisakid may be more common in southern localities also. The infestation of Thyrsites atun by larval and adult T. adunca in the alimentary canal is most influenced by season and closely related to diet. Nematode samples were obtained from the marine mammals Arctocephalus forsteri, Kogia breviceps and Phocarctos hookeri. Adult A. simplex were recorded from A. forsteri (a new host record) and Kogia breviceps; preadults from Phocarctos hookeri. Adult P. decipiens were recorded from Phocarctos hookeri; preadults from Arctocephalus forsteri and K. breviceps. Other anisakids found were Anisakis physeteris (Baylis 1923), Contracaecum osculatum Rudolphi 1802 and Pseudoterranova kogiae (Johnston and Mawson 1939) Mosgovoi 1951. These records are all new for the New Zealand region except P. decipiens from P. hookeri and C. osculatum from Arctocephalus forsteri. A. simplex and C. osculatum were found associated with gastric ulcers in Arctocephalus forsteri.</p>

Studies on Tapeworm Physiology

1949 ◽  
Vol 26 (1) ◽  
pp. 1-15
Author(s):  
J. D. SMYTH
Keyword(s):  
Bacterial Infections ◽  
Detrimental Effect ◽  
Horse Serum ◽  
Body Cavity ◽  
The Body ◽  
Nutrient Media ◽  
Medium Strength ◽  
By Products ◽  
Histochemical Examination

1. Plerocercoid larvae of the pseudophyllidean cestode Ligula intestinalis from the body cavity of roach, were cultured in vitro at 40°C. in a variety of saline and nutrient media. About 65% of such cultures were aseptic. 2. During cultivation, larvae produced acid by-products (unidentified) and the pH fell rapidly. 3. The presence of these acid by-products slowed down development, or, if present in sufficient quantity, caused death. 4. In order to obtain development in nutrient media in a period (3 days) comparable to that required in a bird (the normal host) it was necessary to renew the medium 24-hourly. 5. 6% of the eggs produced from a worm cultured in horse serum were fertile. Fertile eggs were never obtained from larvae cultured in any other media. 6. Certain bacterial infections had no apparent detrimental effect on development, but others were toxic. 7. Some larvae underwent development in non-nutrient medium (¾ strength Locke's solution). The exact conditions under which this occurred was not determined. 8. Fragments (3 cm. long), of larvae or larvae with either scolex or posterior half removed, underwent development to the stage of oviposition in nutrient media. 9. Histochemical examination revealed that the plerocercoid larvae were almost fat-free. During cultivation, very large quantities of cytoplasmic fat were produced the quantity being proportional to the duration of cultivation. Fat was produced even under starvation conditions (i.e. during cultivation in saline) and can be considered a metabolic by-product. 10. The fresh plerocercoid contained great quantities of glycogen in the parenchyma and muscle regions. After cultivation in nutrient or saline media, considerable quantities were still present.

Studies on Tapeworm Physiology

1946 ◽  
Vol 23 (1) ◽  
pp. 47-70 ◽  
Author(s):  
J. D. SMYTH
Keyword(s):  
Histological Examination ◽  
Gasterosteus Aculeatus ◽  
Body Cavity ◽  
Final Host ◽  
The Body ◽  
Normal Behaviour ◽  
The Mean ◽  
Peptone Broth

A technique has been elaborated that enabled the plerocercoid larvae of Schistocephalus solidus to be removed from the body cavity of Gasterosteus aculeatus without bacterial contamination. Larvae were cultured in plugged test-tubes under completely aseptic conditions in a variety of balanced salines, glucose salines and nutrient peptone broth. The most successful results were obtained with peptone broth at room temperatures (16-19° C) in which plerocercoids remained active and showed normal behaviour for periods up to 300 days. In ¾ strength Locke's solution, which was found by experiment to be approximately isotonic with Schistocephalus (δ = -0.44 ± 0.02° C), the mean period of normal behaviour was 114 days. In the remaining saline and saline-glucose media, the mean viability and period of normal behaviour was considerably less. In the plerocercoid, histological examination revealed that the genitalia are in an immature condition. During cultivation at room temperatures, the genitalia remained in this undifferentiated condition and showed no signs of undergoing spermatogenesis, oogenesis or vitellogenesis. Plerocercoids were induced to develop into sexually mature adults by raising the temperature of cultivation in peptone broth to 40° C. (i.e. the body temperature of the final host in the natural life cycle). Oviposition took place after 48-60 hr. at this temperature, and histological examination revealed that spermatogenesis, oogenesis, vitellogenesis and shell formation had taken place in a normal manner. The viability of artificially matured Schistocephalus was 4-6 days in vitro--a period equivalent to the viability of the adult in vivo. The eversion of the cirris was observed in each proglottid after 40 hr. cultivation at 40° C. During the sexual process the cirris everted and invaginated at the rate of about once per second. Cross-fertilization between segments of the same worm or with segments of another worm was not observed. Except for one specimen in ¾ strength Locke's solution which underwent spermatogenesis and partial vitellogenesis, larvae cultured in salines or glucose salines at 40° C. died within 1-3 days without further development. Attempts to hatch out the eggs produced by the cultivation of larvae in peptone broth at 40° C. proved unsuccessful. Histological examination revealed that spermatozoa had not been taken into the vagina. It was concluded that the eggs were not fertilized owing to the failure of normal copulation to take place.

First record of the root knot nematode, Meloidogyne minor in New Zealand with description, sequencing information and key to known species of Meloidogyne in New Zealand 

Zootaxa ◽  
2017 ◽  
Vol 4231 (2) ◽  
pp. 203 ◽  
Author(s):  
ZENG QI ZHAO ◽  
WELLCOME HO ◽  
RUTH GRIFFIN ◽  
MICHAEL SURREY ◽  
ROBERT TAYLOR ◽  
...  
Keyword(s):  
New Zealand ◽  
Large Subunit ◽  
Intergenic Spacer ◽  
First Record ◽  
Small Subunit ◽  
Root Knot Nematode ◽  
Head Region ◽  
Internal Transcribed Spacer Region ◽  
Stage Juvenile ◽  
Labial Disc

Meloidogyne minor Karssen et al. 2004 was collected from perennial ryegrass (Lolium perenne L.) growing in a sports ground in Christchurch, New Zealand. This is a new record for M. minor, the first report of this nematode occurring in New Zealand, and the second report from the southern hemisphere (after Chile). In general, the New Zealand isolate of M. minor corresponds well to the descriptions of M. minor given by Karssen et al. (2004). The New Zealand isolate is characterized by having a female with dorsally curved stylet, 13–14 μm long, with transversely ovoid knobs slightly sloping backwards from shaft; rounded perineal pattern; and male with stylet 16–19 μm long, large transversely ovoid knobs sloping slightly backwards from shaft; head region not set off, labial disc elevated, lateral lips prominent; and second stage juvenile 370–390 μm long, with hemizonid posterior but adjacent to excretory pore; tail 53–63 μm long; and a distinct hyaline tail terminus 14–18 μm long. In addition, molecular phylogeny using near full length small subunit (SSU), D2/D3 expansion segments of the large subunit (LSU), the internal transcribed spacer region (ITS1 and 2), and the intergenic spacer (IGS2) of the ribosomal rDNA supports the identification. 

Studies on tapeworm physiology

Parasitology ◽  
1947 ◽  
Vol 38 (3) ◽  
pp. 173-181 ◽  
Author(s):  
J. D. Smyth
Keyword(s):  
Body Cavity ◽  
The Body ◽  
Cell Stage ◽  
Normal Manner ◽  
Receptaculum Seminis ◽  
Larval Condition ◽  
Aseptic Conditions ◽  
Sexually Mature ◽  
Peptone Broth

The plerocercoid larvae of the pseudophyllidean cestode Ligula intestinalie have been removed from the body-cavity of the roach, Rutilua rutilus, and cultured in vitro under aseptic conditions, using a technique similar to that successfully applied to Schistocephalus solidus.In the larval condition, the genitalia are in a primitive, immature condition, with the testes, ovaries and yolk-glands only partially developed.Larvae were cultured in peptone-broth in plugged tubes at a temperature of 40° C, i.e. the body temperature of birds in which the plerocercoids normally develop into adult worms.Three of the nine larvae used became sexually mature after 7 days' cultivation, and oviposition took place. Copulation between successive genitalia of the same worm or with genitalia of another worm in the same culture tube was not observed.Histological examination revealed that spermatogenesis, oogenesis, vitellogenesis and shell formation had apparently taken place in a normal manner. The testes contained giant polyploid cells as well as mature spermatozoa. The receptaculum seminis contained no spermatozoa, from which it was concluded that fertilization had not taken place. This was confirmed by the fact that attempts to hatch out the eggs were unsuccessful. The unfertilized eggs, however, underwent parthenogenic development within the uterus as far as the two-cell stage. Of the remaining six larvae, four developed sufficiently to undergo eversion of the cirrus, but died without oviposition taking place.

Deladenus nitobei n. sp. (Tylenchomorpha: Allantonematidae) isolated from Sirex nitobei (Hymenoptera: Siricidae) from Aomori, Japan, a new member of the siricidicola superspecies

Nematology ◽  
2016 ◽  
Vol 18 (10) ◽  
pp. 1199-1217 ◽  
Author(s):  
Natsumi Kanzaki ◽  
Suguru E. Tanaka ◽  
Katrin Fitza ◽  
Hajime Kosaka ◽  
Bernard Slippers ◽  
...  
Keyword(s):  
New Species ◽  
Cryptic Species ◽  
Pinus Densiflora ◽  
Large Subunit ◽  
Small Subunit ◽  
Body Cavity ◽  
The Body ◽  
Malt Extract ◽  
Internal Transcribed Spacer Region ◽  
Mtcoi Gene

Deladenus nitobein. sp., a parasite of a woodwasp species,Sirex nitobei, is described based on its typological characters and molecular profiles of part of the small subunit D2-D3 expansion segments of the large subunit and internal transcribed spacer region of the ribosomal RNA gene, as well as part of the mitochondrial cytochrome oxidase subunit I (mtCOI) gene. Adult host woodwasps emerging from dead Japanese red pine logs,Pinus densiflora, collected at Aomori, Japan, were dissected and examined for nematode association. The new species was isolated from the body cavity and reproductive system ofS. nitobeias large parasitic females and small parasitic juveniles. The nematodes were cultured successfully on 1.0% malt extract agar medium, inoculated withSirex-associated fungus,Amylostereumareolatum. The mycophagous adult nematodes were characterised by the relative position of the excretory pore, located at 25 (19-28) and 25 (18-30)μm anterior to the hemizonid in the male and female, respectively, and a broad female tail with a rounded distal end. Typologically, the new species forms a cryptic species complex withD. siricidicolaandD. canii. In addition, the new species andD. siricidicolashare the same host wasp, tree and fungal species in Japan. However, the cryptic species can be separated from each other based on the described morphological and molecular sequence differences in the mtCOI gene.

scholarly journals First description of male Philometra thaiensis Moravec, Fiala et Dyková, 2004 (Nematoda: Philometridae) from the body cavity of the eyespot pufferfish Tetraodon biocellatus Tirant, and evolutionary relationships of this species with other dracunculoids as inferred from SSU rRNA gene sequences

2014 ◽  
Vol 51 (3) ◽  
pp. 236-245 ◽  
Author(s):  
K. Quiazon ◽  
T. Yoshinaga ◽  
H. Doi ◽  
J. Araki ◽  
K. Ogawa
Keyword(s):  
18S Rrna ◽  
Molecular Data ◽  
Small Subunit ◽  
Body Cavity ◽  
The Body ◽  
Evolutionary Relationships ◽  
Rrna Gene ◽  
Taxonomic Identification ◽  
Ssu Rrna ◽  
First Time

Abstract Finding male philometrid nematodes is essential for taxonomic identification among congeneric species. In this study, male Philometra thaiensis Moravec, Fiala et Dyková, 2004 were collected and described for the first time, from the body cavity of the freshwater fish (eyespot pufferfish) Tetraodon biocellatus Tirant (Tetraodontiformes, Tetraodontidae), and conspecific females were redescribed based on the additional morphological biometrics examined. Molecular examination was carried out on the small subunit 18S rRNA, revealing the evolutionary relationships of P. thaiensis and reported philometrid species (Philometra and Philometroides) from Japan with other dracunculoids deposited in the GenBank. Based on the molecular data, there are some genera (Philometra, Philometroides, Clavinema, and Margolisianum [genus inquirendum]) requiring further morphological re-evaluation that should be supported with molecular data.

scholarly journals First record of Bursaphelenchus hildegardae Braasch et al., 2006 (Nematoda) in New Zealand with updated information on morphology, sequencing and a key to species of the eggersi-group

Zootaxa ◽  
2021 ◽  
Vol 5071 (1) ◽  
pp. 151-165
Author(s):  
ZENG QI ZHAO ◽  
MICHAEL SURREY ◽  
WELLCOME HO ◽  
MILEN MARINOV ◽  
CAROLYN BLEACH ◽  
...  
Keyword(s):  
New Zealand ◽  
Internal Transcribed Spacer ◽  
New Record ◽  
Large Subunit ◽  
First Record ◽  
Small Subunit ◽  
Key To Species ◽  
Internal Transcribed Spacer Region ◽  
Adult Body ◽  
Hylastes Ater

Bursaphelenchus hildegardae Braasch et al., 2006 was collected from pine wood (Pinus radiata) growing in Kaingaroa Timberlands, and a bark beetle, Hylastes ater Paykull, 1800 in New Zealand. This is a new record for B. hildegardae, occuring in New Zealand, and the second report from the southern hemisphere in addition to Australia. In general, the New Zealand isolate of B. hildegardae corresponds well with the description of B. hildegardae given by Braasch et al. (2006) from Germany. The New Zealand isolate is characterized by having an adult body length of 807–1190 μm, medium a ratios (47.5–58.5 for female and 44.6–60.1 for male), b ratios of 9.8–14.5 (female) and 10.2–12.7 (male), c ratios of 18.8–25.2 (female) and 21.6–32.4 (male), c’ ratios of 4.0–4.4 (female) and 2.1–2.7 (male), and is characterised by having three incisures in the lateral fields, thorn-shaped spicules with a distinctly dorsally-bent thin hook-like condylus, and a dorso-ventally visible terminal bursa. In addition, molecular phylogeny using near full length small subunit (SSU), D2/D3 expansion segments of the large subunit (LSU) and the internal transcribed spacer region (ITS1 and 2) of the ribosomal rDNA supports the identification. A key to Bursaphelenchus species in the eggersi-group is given.  

The egg sorting function of the uterine bell of Polymorphus minutus (Acanthocephala)

Parasitology ◽  
1970 ◽  
Vol 61 (1) ◽  
pp. 111-126 ◽  
Author(s):  
P. J. Whitfield
Keyword(s):  
Adult Female ◽  
Muscular Activity ◽  
Body Cavity ◽  
Final Host ◽  
The Body ◽  
Duct Cells ◽  
Age Structures

An adult female Polymorphus minutus releases only mature eggs into the intestine of its final host. These eggs come from the pool of eggs in the body cavity of the worm which contains only about 30% of mature eggs, the rest being immature. An analysis of the age structures of the egg populations in the body cavity and the uterus shows that an assortment of mature and immature eggs has taken place as the eggs pass from the body cavity to the uterus. The uterus contains only mature eggs and these are the eggs which are about to be released. The only pathway whereby eggs can enter the uterus from the body cavity is through the uterine bell. This suggests that it is the uterine bell which is able to select mature eggs from the mixture of eggs in the body cavity.A uterine bell in vitro engages in precisely patterned muscular activity which propels eggs through its branching lumen. In one part of the bell (the grooves between the median wall cells and the lappets of the uterine duct cells), the patterned muscular activity passes mature eggs into the uterus and immature eggs back into the body cavity to complete their development. The greater length of mature eggs seems to be the character which enables them to be ‘recognized‘ by the uterine bell.

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