Moulting and mating in Lepeophtheirus pectoralis (Copepoda: Caligidae)

1990 ◽  
Vol 70 (2) ◽  
pp. 269-281 ◽  
Author(s):  
Morten Anstensrud
Keyword(s):  
Adult Female ◽  
Anterior Margin ◽  
Ventral Side ◽  
Dorsal Side ◽  
The Body ◽  
Agonistic Behaviour ◽  
Free Living ◽  
Genital Complex ◽  
Frontal Filament ◽  
Receptaculum Seminis

Prior to moulting, the preadult Lepeophtheirus pectoralis produces a temporary frontal filament which attaches the animal to the surface of the host during ecdysis. This filament is extruded from a frontal organ previously thought to have a chemoreceptory function. During ecdysis the exuvium splits at the anterior margin and is shed posteriorly by contractions of the body. After hardening of the exoskeleton the copepod detaches itself from the frontal filament and is free-living on the host during intermoult. Males in precopula position hold on to the dorsal side of the female, with the second antennae grasping the anterior end of the female's genital complex. During the ecdysis of the female, most males release their hold on the female, and are usually found close to her on the host. Copulation occurs between an adult male and an adult female with a hardened exoskeleton. In the copula position the male holds on to the female's genital complex with the second antennae, but now on the ventral side of the female. Two spermatophores are extruded and then transferred simultaneously to the female with the aid of the second pair of swimming legs. Tubes originating from the spermatophores connect them to the orifices of the receptaculum seminis. These tubes seem to grow out of the spermatophores after expulsion. After copulation, the male retains a precopula position before releasing the female. No agonistic behaviour has been observed between a precopulating/copulating male and additional males. However, during the ecdysis of the female, a new male may take over the female, but mating does not seem to be assortative for size in Lepeophtheirus pectoralis.

Fasciola gigantica: surface topography of the adult tegument

2001 ◽  
Vol 75 (1) ◽  
pp. 43-50 ◽  
Author(s):  
T. Dangprasert ◽  
W. Khawsuk ◽  
A. Meepool ◽  
C. Wanichanon ◽  
V. Viyanant ◽  
...  
Keyword(s):  
Anterior Part ◽  
Ventral Side ◽  
Ventral Surface ◽  
Dorsal Side ◽  
Fasciola Gigantica ◽  
The Body ◽  
Lateral Aspect ◽  
Tegumental Surface ◽  
Type 3

Adult Fasciola gigantica are leaf-shaped with tapered anterior and posterior ends and measure about 35 mm in length and 15 mm in width across the mid section. Under the scanning electron microscope its surface appears rough due to the presence of numerous spines and surface foldings. Both oral and ventral suckers have thick rims covered with transverse folds and appear spineless. On the anterior part of the ventral surface of the body, the spines are small and closely-spaced. Each spine has a serrated edge with 16 to 20 sharp points, and measures about 20 μm in width and 30 μm in height. In the mid-region the spines increase in size (up to 54 μm in width and 58 μm in height) and number, especially towards the lateral aspect of the body. Towards the posterior end the spines progressively decrease in both size and number. The tegumental surface between the spines appears highly corrugated with transverse folds alternating with grooves. At higher magnifications the surface of each fold is further increased with a meshwork of small ridges separated by variable-sized pits or slits. There are three types of sensory papillae on the surface. Types 1 and 2 are bulbous, measuring 4–6 μm in diameter at the base with nipple-like tips, and the type 2 also have short cilia. Type 3 papillae are also bulbous and of similar size but with a smooth surface. These sensory papillae usually occur in clusters, each having between 2 and 15 units depending on the region of the body. Clusters of papillae on the lateral aspect (usually types 1 and 2) and around the suckers (type 3) tend to be more numerous and larger in size. The dorsal side of the body exhibits similar surface features, but the spines and papillae appear less numerous and are smaller. Corrugation and invaginations of the surface are also less extensive than on the ventral side of the body.

scholarly journals A new millipede-parasitizing horsehair worm, Gordius chiashanus sp. nov., at medium altitudes in Taiwan (Nematomorpha, Gordiida)

ZooKeys ◽  
2020 ◽  
Vol 941 ◽  
pp. 25-48
Author(s):  
Ming-Chung Chiu ◽  
Chin-Gi Huang ◽  
Wen-Jer Wu ◽  
Zhao-Hui Lin ◽  
Hsuan-Wien Chen ◽  
...  
Keyword(s):  
Forest Canopy ◽  
Heavy Rain ◽  
Paratenic Host ◽  
Ventral Side ◽  
The Body ◽  
High Tolerance ◽  
Free Living ◽  
Terrestrial Environment ◽  
White Stripe ◽  
Inside Wall

Gordius chiashanussp. nov., a newly described horsehair worm that parasitizes the Spirobolus millipede, is one of the three described horsehair worm species in Taiwan. It is morphologically similar to G. helveticus Schmidt-Rhaesa, 2010 because of the progressively broadening distribution of bristles concentrated on the male tail lobes, but it is distinguishable from G. helveticus because of the stout bristles on the mid-body. In addition, a vertical white stripe on the anterior ventral side and areoles on the inside wall of the cloacal opening are rarely mentioned in other Gordius species. Free-living adults emerged and mated on wet soil under the forest canopy in the winter (late November to early February) at medium altitudes (1100–1700 m). Mucus-like structure covering on the body surface, which creates a rainbow-like reflection, might endow the worm with high tolerance to dehydration. Although Gordius chiashanussp. nov. seems to be more adaptive to the terrestrial environment than other horsehair worm species, cysts putatively identified as belonging to this hairworm species found in the aquatic paratenic host, Ephemera orientalis McLachlan, 1875, suggest the life cycle of Gordius chiashanussp. nov. could involve water and land. The free-living adults emerged from the definitive hosts might reproduce in the terrestrial environment or enter an aquatic habitat by moving or being washed away by heavy rain instead of manipulating the behavior of their terrestrial definitive hosts.

scholarly journals Anatomical basis of erector spinae plane block: a dissection and histotopographic pilot study

2020 ◽  
Author(s):  
Daniele Bonvicini ◽  
Rafael Boscolo-Berto ◽  
Alessandro De Cassai ◽  
Michele Negrello ◽  
Veronica Macchi ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Ventral Side ◽  
Dorsal Side ◽  
The Body ◽  
Erector Spinae ◽  
Paravertebral Space ◽  
Anatomical Dissection ◽  
Anatomical Basis ◽  
Clinical Scenarios ◽  
Dye Diffusion

Abstract Purpose Erector spinae plane (ESP) block is an interfascial blockade used in different clinical scenarios. This study investigated the ventral extent of dye diffusion in ESP block. Methods The ultrasound-guided ESP block was bilaterally performed with an injection at the T5 vertebral level (21-Gauge, 50 mm needle), using diluted black tissue marking dye (20 mL; 1:4 ratio with standard saline solution) instead of local anesthetic on two fresh-frozen corpses within the body donation program of the University of Padova. Subsequently, the gross anatomical dissection was performed by a combined posterior plus anterior approach, and the histotopographic examination completed. Results Macroscopically by gross anatomical dissection, the dye spreading ranged on the dorsal side of the chest from T2/3 to T10/11 with an extension up to 10 cm laterally, and on the ventral side of the chest from T2/3–T9/10. Microscopically by histotopographic examination, the dye diffused ventrally to the intercostal spaces (2–3 and 5–6 spaces on the right and left, respectively) by following the blood vessels coupled to the dorsal nerve passing through the costotransverse foramen. Conclusions The anterior pathway of dye diffusion from the site of injection within the erector spinae muscle group during an ESP block seems to follow the blood vessels and dorsal rami of spinal nerves, suggesting the passing through the costotransverse foramen to reach the anterior paravertebral space and the intercostal nerves. These findings display an anterior histotopographic diffusion of dye resembling a paravertebral block.

On Microstrongylus genetiæ gen. and sp. nov., a Trichostrongyle Parasite of Genetta senegalensis

1927 ◽  
Vol 5 (2) ◽  
pp. 81-88 ◽  
Author(s):  
Thomas W. M. Cameron
Keyword(s):  
Small Intestine ◽  
Excretory Pore ◽  
Posterior Margin ◽  
Anterior Margin ◽  
Body Wall ◽  
Ventral Side ◽  
The Body ◽  
Zoological Society ◽  
Granular Inclusion ◽  
Cephalic Extremity

A Considerable number of specimens of this parasite were collected from the small intestine of a genette which died in the Gardens of the Zoological Society of London.The cuticle of the cephalic extremity is dilated anteriorly. This swelling is terminated posteriorly by the cuticle incurving to meet a raised ring on the body-wall, about the level of the junction of the anterior and second fifths of the œsophagus. There are no cervical papillæ present, and it is probable that this ring may be regarded as replacing them. Just anterior to the middle of the œsophageal region and at the level of the excretory pore is a cervical groove which completely encircles the body. Laterally the cuticle on the anterior margin is thickened; it is also thickened on the ventral side, but less so than laterally. These thickenings are reinforced by a granular inclusion in the cuticle. The posterior margin is thickened only in the region of the excretory pore.

The life cycle of the Tantulocarida (Crustacea)

1987 ◽  
Vol 315 (1173) ◽  
pp. 267-303 ◽  
Keyword(s):  
Life Cycle ◽  
Adult Female ◽  
Adult Male ◽  
Deep Sea ◽  
The Body ◽  
Dispersal Ability ◽  
Free Living ◽  
Unique Type ◽  
High Dispersal ◽  
Living Adult

Four new species of parasitic crustaceans belonging to the class Tantulocarida are described, two of which are placed in a new genus, Onceroxenus . Three of them parasitize deep-sea tanaids, the other, a deep sea asellote. Microdajus langi , originally classified as an epicaridean isopod, is recognized as a tantulocaridan. It is reported from Scottish waters for the first time and from new host species. These records include the shallowest depth, 22 m, known for a tantulocaridan. Cumoniscus kruppi a parasite of cumaceans, is also recognized as a tantulocaridan. The Tantulocarida now comprises eleven species and five genera, here assigned to the Basipodellidae and two new families, the Deoterthridae and Microdajidae. Several life cycle stages are described and arranged in two developmental sequences. Evidence for a possible third sequence was found. Male development involves a unique type of metamorphosis in which the free-living adult differentiates from a dedifferentiated mass of tissue contained within the expanded trunk of the tantulus larva. Throughout this metamorphosis the male is supplied with nutrients from the host via a tissue connection, the umbilical cord, and the permanently attached larval head. The non-feeding adult male lacks cephalic appendages but possesses two clusters of aesthetascs on its anterior margin. It is free swimming and has six pairs of large thoracopods without endites. The first two thoracic somites are incorporated into the cephalothorax. The abdomen bears a posteriorly directed, median stylet, interpreted as the intromittent organ. It originates on the first abdominal somite. The adult female has a large sac-like trunk attached by the larval head. The larval trunk is sloughed leaving a scar but no complete moult occurs. Eggs develop within the trunk sac and hatch directly at the infective tantulus larval stage. This extreme condensation of early ontogeny is compared with that of other crustaceans and is interpreted as an adaptation to parasitism in situations where a high dispersal ability is not advantageous. In some females the trunk sac forms behind the head but the larval trunk is retained. Small and large females of this type are described, the largest being 737 µm in length. These probably represent females in which sloughing of the larval trunk has failed but it is possible that each may have contained a free-living adult female of comparable size to the adult male. The tantulus larva is described in detail. Scanning electron microscopy reveals that the thoracopodal endites have a complex apical armature, including coupling spines which serve to link the members of a leg pair. Tantulocaridans are permanently attached to their host by the oral disc, presumably by means of an adhesive. In the centre of the disc they make a minute puncture (between 0.5 and 2.0 µm in diameter) through the host integument, probably with the aid of their cephalic stylet. This constitutes their only access to the body fluids of the host. The phylogenetic relationships of the Tantulocarida are discussed. They appear to be related to the barnacles (Thecostraca), both groups possessing a median penis derived from the seventh trunk limb. Their possession of a thorax of six somites and the location of the male gonopores on trunk somite seven suggests an affinity with a larger group containing the Thecostraca and the Copepoda.

scholarly journals The geometry of insect pairing

1922 ◽  
Vol 94 (656) ◽  
pp. 1-11 ◽  
Keyword(s):  
Median Plane ◽  
Bilateral Symmetry ◽  
Ventral Side ◽  
Dorsal Side ◽  
The Body ◽  
Anal Orifice ◽  
The One ◽  
Special Points ◽  
Asymmetrical Condition ◽  
Axial Twist

In insects bilateral symmetry is practically universal, except in some minor matters, as, for example, the slight overlap of the elytra exhibited by many beetles. In the females the symmetrical condition may be taken to be almost universal, but the males in certain families exhibit asymmetry, which in some cases is very extreme, in the terminal segments of the abdomen. It is with this condition that the present paper deals, and the simplest course to pursue is, first to state the case as shown by some species of Diptera, that being the Order most familiar to the author and one in which an asymmetrical condition is comparatively common, then to outline a possible explanation of the phenomenon, in the course of which certain terms will be defined in order to clear the ground of existing ambiguities. Certain statements made in the course of the argument will then be justified as far as possible, and, finally, a few special points will be discussed. In most insects, excluding such aberrant forms as the dragon-flies, the genital tube opens on the under side of the 9th abdominal segment, and the anal orifice is in the 10th. Let us trace a line in the vertical median plane of the insect, beginning on the dorsal side of the abdomen and proceeding round to the ventral side. On such a peregrination we shall first encounter the anal orifice and subsequently the genital one; this is true for all females and for most males, but there are some remarkable exceptions. Thus, it was shown by Snodgrass that in the Asilid genera Dascillis and Laphria a different condition exists. On referring to the figures in that paper, it will be seen that on tracing such a line round the insect in its median plane the genital orifice is met before the anal one ; the hypopygium is then said to be “inverted.” The term “hypopygium” will be used for the combination of the 9th and 10th segments, which are commonly fused into a single complex in flies, so that no movement of the one segment relative to the other is possible, and the two segments must always behave kinematically as a single body. This inversion is produced by the presence of a twist of 180° about the main axis of the body between the 6th segment and the hypopygium; the 8th segment is quite unsymmetrieal and has an axial twist of about 150°; the hypopygium has the complete twist of 180°, but nevertheless it is practically symmetrical about the median plane which still bisects it. The result of this twist is to produce a true asymmetry, although it may not be very apparent on casual examination; in fact, not until the relative positions of the orifices are looked into.

scholarly journals Gravity determines the direction of nerve roots sedimentation in the lumbar spinal canal

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jun Yang ◽  
Zhiyun Feng ◽  
Nian Chen ◽  
Zhenhua Hong ◽  
Yongyu Zheng ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Mr Imaging ◽  
Spinal Canal ◽  
Ventral Side ◽  
Lateral Position ◽  
Dorsal Side ◽  
Mr Images ◽  
Nerve Roots ◽  
Cross Sectional ◽  
Dural Sac

Abstract Objectives To investigate the role of gravity in the sedimentation of lumbar spine nerve roots using magnetic resonance (MR) imaging of various body positions. Methods A total of 56 patients, who suffered from back pain and underwent conventional supine lumbar spine MR imaging, were selected from sanmen hospital database. All the patients were called back to our hospital to perform MR imaging in prone position or lateral position. Furthermore, the sedimentation sign (SedSign) was determined based on the suspension of the nerve roots in the dural sac on cross-sectional MR images, and 31 cases were rated as positive and another 25 cases were negative. Results The mean age of negative SedSign group was significantly younger than that of positive SedSign group (51.7 ± 8.7 vs 68.4 ± 10.5, P < 0.05). The constitutions of clinical diagnosis were significantly different between patients with a positive SedSign and those with a negative SedSign (P < 0.001). Overall, nerve roots of the vast majority of patients (48/56, 85.7%) subsided to the ventral side of the dural sac on the prone MR images, although that of 8 (14.3%) patients remain stay in the dorsal side of dural sac. Nerve roots of only one patient with negative SedSign did not settle to the ventral dural sac, while this phenomenon occurred in 7 patients in positive SedSign group (4% vs 22.6%, P < 0.001). In addition, the nerve roots of all the five patients subsided to the left side of dural sac on lateral position MR images. Conclusions The nerve roots sedimentation followed the direction of gravity. Positive SedSign may be a MR sign of lumbar pathology involved the spinal canal.

Invariance of Wearing Location of Omron-BI Pedometers: A Validation Study

2010 ◽  
Vol 7 (6) ◽  
pp. 706-717 ◽  
Author(s):  
Weimo Zhu ◽  
Miyoung Lee
Keyword(s):  
Validation Study ◽  
Absolute Error ◽  
Activity Monitor ◽  
Error Rates ◽  
Living Conditions ◽  
The Body ◽  
Validity And Reliability ◽  
Free Living ◽  
Climbing Stairs ◽  
Free Living Conditions

Background:The purpose of this study was to investigate the validity and reliability evidences of the Omron BI pedometer, which could count steps taken even when worn at different locations on the body.Methods:Forty (20 males and 20 females) adults were recruited to walk wearing 5 sets, 1 set at a time, of 10 BI pedometers during testing, 1 each at 10 different locations. For comparison, they also wore 2 Yamax Digi-Walker SW-200 pedometers and a Dynastream AMP 331 activity monitor. The subjects walked in 3 free-living conditions: a fat sidewalk, stairs, and mixed conditions.Results:Except for a slight decrease in accuracy in the pant pocket locations, Omron BI pedometers counted steps accurately across other locations when subjects walked on the fat sidewalk, and the performance was consistent across devices and trials. When the subjects climbed up stairs, however, the absolute error % of the pant pocket locations increased significantly (P < .05) and similar or higher error rates were found in the AMP 331 and SW-200s.Conclusions:The Omron BI pedometer can accurately count steps when worn at various locations on the body in free-living conditions except for front pant pocket locations, especially when climbing stairs.

Taxonomic description and 3D modelling of a new species of myzostomid (Annelida, Myzostomida) associated with black corals from Madagascar

Zootaxa ◽  
2017 ◽  
Vol 4244 (2) ◽  
pp. 277 ◽  
Author(s):  
LUCAS TERRANA ◽  
IGOR EECKHAUT
Keyword(s):  
New Species ◽  
Phylogenetic Analyses ◽  
Three Dimensional ◽  
Close Relation ◽  
Ventral Side ◽  
Middle Part ◽  
The Body ◽  
Taxonomic Description ◽  
Black Corals ◽  
Organ Systems

Eenymeenymyzostoma nigrocorallium n. sp. is the first species of myzostomid worm associated with black corals to be described. Endoparasitic specimens of E. nigrocorallium were found associated with three species of antipatharians on the Great Reef of Toliara. Individuals inhabit the gastrovascular ducts of their hosts and evidence of infestation is, most of the time, not visible externally. Phylogenetic analyses based on 18S rDNA, 16S rDNA and COI data indicate a close relation to Eenymeenymyzostoma cirripedium, the only other species of the genus. The morphology of E. nigrocorallium is very unusual compared to that of the more conventional E. cirripedium. The new species has five pairs of extremely reduced parapodia located on the body margin and no introvert, cirri or lateral organs. Individuals are hermaphroditic, with the male and female gonads both being located dorsally in the trunk. It also has a highly developed parenchymo-muscular layer on the ventral side, and the digestive system lies in the middle part of the trunk. A three-dimensional digital model of this worm’s body plan has been constructed whereby the external morphology and in toto views of the observed organ systems (nervous, digestive and reproductive) can be viewed on-screen: http://doi.org/10.13140/RG.2.2.17911.21923. 

Sign in / Sign up

Export Citation Format

Share Document