THE SYSTEMATICS AND TRANSMISSION OF NEW AND PREVIOUSLY DESCRIBED METASTRONGYLES (NEMATODA : METASTRONGYLIDAE) FROM MUSTELA VISON

1962 ◽  
Vol 40 (5) ◽  
pp. 893-920 ◽  
Author(s):  
Roy C. Anderson

Crenosoma hermani n. sp., Aelurostrongylus pridhami n. sp., and Filaroides martis from mink are described. A. pridhami developed in the terrestrial gastropods Zonitoides arboreus, Discus cronkhitei, Deroceras gracile, Succinea ovalis, and Anguispira alternata and the aquatic snails Physa integra, Gyraulus deflexus, Armiger crista, and Ampullaria cuprina. F. martis developed in P. integra and G. deflexus as well as in the foregoing terrestrial gastropods. Larvae of A. pridhami and F. martis infected gastropods by penetrating the foot but those ingested penetrated the gut wall and developed successfully. Besides the foot, larvae developed on, or within, the body wall, in the mantle, on the gut, on the surface of the liver, in the buccal mass, salivary gland, and rarely in the albumen gland of molluscs. At 22–23 °C the first molt occurred on the 5th to 6th day, the second on the 13th; the three larval stages are described. The prepatent period of A. pridhami was 21–28 days, F. martis 41–53 days. Mink invariably vomited when fed infective larvae of A. pridhami but not when fed F. martis. Infective larvae of A. pridhami became encapsulated in the liver of mice, small birds, and frogs but on the intestines and mesenteries of goldfish. F. martis larvae became encapsulated in the liver of mice. There is a sigmoidal relationship between temperature and activity of first-stage larvae of A. pridhami. Young D. gracile fed and became infected with A. pridhami and F. martis at temperatures as low as 5 °C. Desiccation killed larvae in a few minutes and they survived freezing temperatures for only 4 to 5 days.

1954 ◽  
Vol s3-95 (30) ◽  
pp. 251-270
Author(s):  
G. P. WELLS

The mechanism of proboscis movement is analysed in detail in Arenicola marina L. and A. ecaudata Johnston, and discussed in relation to the properties of the hydrostatic skeleton. Proboscis activity is based on the following cycle of movements in both species. Stage I. The circular muscles of the body-wall and buccal mass contract; the head narrows and lengthens. Stage IIa. The circular muscles of the mouth and buccal mass relax; the gular membrane (or ‘first diaphragm’ of previous authors) contracts; the mouth opens and the buccal mass emerges. Stage IIb. The longitudinal muscles of the buccal mass and body-wall contract; the head shortens and widens and the pharynx emerges. Stage III. As Stage I. The two species differ anatomically and in their hydrostatic relationships. In ecaudata, the forward movement of body-fluid which extrudes and distends the proboscis is largely due to the contraction of the gular membrane and septal pouches. In marina, the essential mechanism is the relaxation of the oral region which allows the general coelomic pressure to extrude the proboscis. The gular membrane of marina contracts as that of ecaudata does, but its anatomy is different and it appears to be a degenerating structure as far as proboscis extrusion is concerned. Withdrawal of the proboscis may occur while the head is still shortening and widening in Stage IIb, or while it is lengthening and narrowing in Stage III. The proboscis is used both in feeding and in burrowing; in the latter case nothing enters through the mouth; the difference is largely caused by variation in the timing of withdrawal relative to the 3-stage cycle.


2010 ◽  
Vol 55 (2) ◽  
Author(s):  
Oleg Tolstenkov ◽  
Nadezhda Terenina ◽  
Elena Serbina ◽  
Margaretha Gustafsson

AbstractThe organisation of the neuromuscular system in cercariae, metacercariae and adult Opisthorchis felineus was studied. The patterns of nerves immunoreactive (IR) to antibodies towards serotonin (5-HT) and FMRFamide are described in relation to the musculature, stained with TRITC-conjugated phalloidin. The general organisation of the musculature in the body wall, suckers, pharynx, intestine and sphincter of the excretory pore remains the same from the larval stages to the adult worms. However, the diameter of the individual muscle fibres increases distinctly in the adult worms. The general pattern of 5-HT IR fibres in cercariae, metacercariae and adult O. felineus remains the same. Despite the large increase in body size, the number of 5-HT IR neurones remains almost the same in the cercariae and metacercariae and only a modest increase in number of neurones was observed in the adult worms. Thus the proportion of 5-HT IR neurones/body mass is greatest in the actively moving cercariae. Anti-FMRFamide stains the nervous system strongly.


Development ◽  
1996 ◽  
Vol 122 (12) ◽  
pp. 3921-3928 ◽  
Author(s):  
S. Gonzalez-Crespo ◽  
G. Morata

Arthropod appendages are thought to have evolved as outgrowths from the body wall of a limbless ancestor. Snodgrass, in his Principles of Insect Morphology (1935), proposed that, during evolution, expansion of the body wall would originate the base of the appendages, or coxopodite, upon which the most distal elements that represent the true outer limb, or telopodite, would develop. The homeobox gene Distal-less (Dll), which is required in the Drosophila appendages for development of distal regions, has been proposed to promote formation of telopodite structures above the evolutionary ground-state of non-limb or body wall. Here, we present evidence that another homeobox gene, extradenticle (exd), which is required for appropriate development of the trunk and the proximal parts of the appendages, represents a coxopodite gene. We show that exd function is eliminated from the distal precursors in the developing limb and remains restricted to proximal precursors throughout development. This elimination is important because, when ectopically expressed, exd prevents distal development and gives rise to truncated appendages lacking distal elements. Moreover, the maintenance of exd expression during larval stages, contrary to Dll, does not require the hedgehog (hh) signaling pathway, suggesting that the proximal regions of the appendages develop independently of hh function. Finally, we show that in the crustacean Artemia, exd and Dll are expressed in comparable patterns as in Drosophila, suggesting a conserved genetic mechanism subdividing the arthropod limb.


1984 ◽  
Vol 62 (5) ◽  
pp. 965-979 ◽  
Author(s):  
Cheryl M. Bartlett

Development of Dirofilaria scapiceps (Leidy, 1886) was followed in 34 experimentally infected cottontail rabbits (Sylvilagus floridanus). Worms were recovered from all rabbits and intensity ranged from 8 to 76% of the number of infective larvae inoculated. Development to subadults occurred in subcutaneous tissues in various regions of the body; the specific region was influenced by the site of inoculation. The third and fourth moults occurred at 6 and 12 days postinoculation, respectively. Subadults migrated through the subcutaneous tissues and arrived in the ankles as early as 16 days postinoculation. Worms were sexually mature by 67 days. The prepatent period was 137–234 days and the microfilaraemia was nonperiodic. Few worms in cottontail rabbits degenerated or died and rabbits with 1-year-old infections could be reinfected. Dirofilaria scapiceps was recovered from 12 of 14 experimentally inoculated snowshoe hares (Lepus americanus) and 2 of 4 New Zealand white domestic rabbits (Oryctolagus cuniculus). Intensity in snowshoe hares and domestic rabbits ranged from 0.4 to 15% and 6 to 7%, respectively, of the number of infective larvae inoculated. Many worms in these hosts degenerated or died.


Parasitology ◽  
1924 ◽  
Vol 16 (3) ◽  
pp. 269-278 ◽  
Author(s):  
I. M. Puri

The stink organs are different in structure and position in the adult and the larval stages.The stink organs of the adult are composed of (a) a pair of glands, (b) a central reservoir with two backwardly-directed lateral reservoirs, (c) a median kidney-shaped organ in the central reservoir, and (d) a pair of lateral external openings.Each gland is a multicellular compound structure, opening into the central reservoir. It is described for the first time in this paper.The whole of the stink organ of the adult is formed in the last larval stage from a pair of invaginations of the epithelial lining of the body-wall.In the larval stages the stink organs are simple glands, situated dorsally in abdominal segments III to V.The function of the stink organs is defensive and in the adult perhaps also sexual.


2015 ◽  
Vol 112 (14) ◽  
pp. 4195-4201 ◽  
Author(s):  
Shannon Stewart ◽  
Tong-Wey Koh ◽  
Arpan C. Ghosh ◽  
John R. Carlson

We examine in Drosophila a group of ∼35 ionotropic receptors (IRs), the IR20a clade, about which remarkably little is known. Of 28 genes analyzed, GAL4 drivers representing 11 showed expression in the larva. Eight drivers labeled neurons of the pharynx, a taste organ, and three labeled neurons of the body wall that may be chemosensory. Expression was not observed in neurons of one taste organ, the terminal organ, although these neurons express many drivers of the Gr (Gustatory receptor) family. For most drivers of the IR20a clade, we observed expression in a single pair of cells in the animal, with limited coexpression, and only a fraction of pharyngeal neurons are labeled. The organization of IR20a clade expression thus appears different from the organization of the Gr family or the Odor receptor (Or) family in the larva. A remarkable feature of the larval pharynx is that some of its organs are incorporated into the adult pharynx, and several drivers of this clade are expressed in the pharynx of both larvae and adults. Different IR drivers show different developmental dynamics across the larval stages, either increasing or decreasing. Among neurons expressing drivers in the pharynx, two projection patterns can be distinguished in the CNS. Neurons exhibiting these two kinds of projection patterns may activate different circuits, possibly signaling the presence of cues with different valence. Taken together, the simplest interpretation of our results is that the IR20a clade encodes a class of larval taste receptors.


1982 ◽  
Vol 60 (12) ◽  
pp. 3010-3020 ◽  
Author(s):  
T. H. J. Gilmour

The food-collecting and waste-rejecting systems of the tornaria larval stages of enteropneust hemichordates are similar to those of larval and adult lophophorates and adult pterobranch hemichordates. Water entering the oral grooves is deflected towards the mouth and the impetus of heavy, potentially inedible particles may take them across the flow lines of the water currents inferred from the movements of suspended particles to impinge on cilia which reject them into the outgoing water currents. Lighter, potentially edible material remaining suspended in the deflected water currents is intercepted by cilia on an oral hood which is similar in structure and function to the preoral lobe of the actinotroch larvae of phoronids. Excess water carried into the mouth by cilia on the dorsal surface of the esophagus is rejected via lateral grooves which develop into pouches prior to metamorphosis. Following metamorphosis the pouches make contact with the body wall to form gill slits which continue to allow water to escape from the pharynx. This finding that the function of allowing excess water to escape is performed by lateral grooves in the esophagus of tornariae supports previous speculations on the evolution of gill slits and provides further evidence for relationships between lophophorates, hemichordates, and chordates.


Zootaxa ◽  
2007 ◽  
Vol 1401 (1) ◽  
pp. 53 ◽  
Author(s):  
ROGER-DANIEL RANDRIANIAINA ◽  
FRANK GLAW ◽  
MEIKE THOMAS ◽  
JULIAN GLOS ◽  
NOROMALALA RAMINOSOA ◽  
...  

We describe the larval stages of two Malagasy frog species of the genus Gephyromantis, based on specimens identified by DNA barcoding. The tadpoles of Gephyromantis ambohitra are generalized stream-living Orton type IV type larvae with two lateral small constrictions of the body wall at the plane of spiracle. Gephyromantis pseudoasper tadpoles are characterized by totally keratinised jaw sheaths with hypertrophied indentation, a reduced number of labial tooth rows, enlarged papillae on the oral disc, and a yellowish coloration of the tip of the tail in life. The morphology of the tadpole of G. pseudoasper agrees with that of G. corvus, supporting the current placement of these two species in a subgenus Phylacomantis, and suggesting that the larvae of G. pseudoasper may also have carnivorous habits as known in G. corvus. Identifying the tadpole of Gephyromantis ambohitra challenges current assumptions of the evolution of different developmental modes in Gephyromantis, since this species is thought to be related to G. asper, a species of supposedly endotrophic direct development.


Zootaxa ◽  
2007 ◽  
Vol 1401 (1) ◽  
pp. 53 ◽  
Author(s):  
ROGER-DANIEL RANDRIANIAINA ◽  
FRANK GLAW ◽  
MEIKE THOMAS ◽  
JULIAN GLOS ◽  
NOROMALALA RAMINOSOA ◽  
...  

We describe the larval stages of two Malagasy frog species of the genus Gephyromantis, based on specimens identified by DNA barcoding. The tadpoles of Gephyromantis ambohitra are generalized stream-living Orton type IV type larvae with two lateral small constrictions of the body wall at the plane of spiracle. Gephyromantis pseudoasper tadpoles are characterized by totally keratinised jaw sheaths with hypertrophied indentation, a reduced number of labial tooth rows, enlarged papillae on the oral disc, and a yellowish coloration of the tip of the tail in life. The morphology of the tadpole of G. pseudoasper agrees with that of G. corvus, supporting the current placement of these two species in a subgenus Phylacomantis, and suggesting that the larvae of G. pseudoasper may also have carnivorous habits as known in G. corvus. Identifying the tadpole of Gephyromantis ambohitra challenges current assumptions of the evolution of different developmental modes in Gephyromantis, since this species is thought to be related to G. asper, a species of supposedly endotrophic direct development.


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