Observations on the behaviour of Thalassema thalassemum (echiura: echiuridae)

1994 ◽  
Vol 74 (4) ◽  
pp. 963-966
Author(s):  
L.A. Nickell ◽  
R.J.A. Atkinson
Keyword(s):  
Significant Contribution ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Distal Portion ◽  
Sediment Surface ◽  
Ciliary Movement ◽  
Faecal Pellets ◽  
Particle Collection ◽  
Closed Tube ◽  
Sediment Particles

The echiuran worm Thalassema thalassemum (Echiura: Echiuridae), is a deposit-feeder which uses its proboscis to collect sediment particles for ingestion. The proboscis is highly extensible and is used with dorsal surface downwards to skim particles from the sediment surface. Alternatively, the distal portion of the proboscis is arched over and the ventral surface of the tip is held against the sediment surface where ciliary movement facilitates particle collection. These methods are used in combination and collected material is moved back along the proboscis, the edges of which are rolled to form a closed tube. Burrows appear to be U-shaped with one predominantly inhalant and one exhalant opening. Faecal pellets are periodically ejected forming small mounds around exhalant openings and mean rates of 1·83 and 2·80 g dry wt d−1 were measured suggesting that, in sufficient densities, this species could make a significant contribution to macrofaunal bioturbation.

Revision of the class Cyclocystoidea (Echinodermata)

1982 ◽  
Vol 296 (1083) ◽  
pp. 577-679 ◽  
Keyword(s):  
Dorsal Surface ◽  
Ventral Surface ◽  
Sediment Surface ◽  
Single Family ◽  
Generic Level ◽  
Narrow Channels ◽  
Middle Ordovician ◽  
Annular Plates ◽  
Oral Surface ◽  
Almost All

Almost all known cyclocystoid specimens have been examined and the class revised. Cyclocystoids are very distinctive and consist of a complexly plated disc surrounded by a marginal ring of stout, perforate, cupule-bearing ossicles, in turn encircled by a narrow, flexible, plated peripheral skirt. The disc consists of: (1) a ventral surface with branched rays bearing irregular, immovable cover plates over narrow channels and unbranched interrays (except in Actinodiscus nov.); both uniserial and composed of imbricate plates; and (2) a dorsal surface usually covered by polygonal, annular plates. Sutural pores occur between radial and interradial plates ventrally and align exactly with the central perforations of the dorsal annular plates. A ventral mouth and dorsal anus occur subcentrally in the disc. The marginal ring consists of large ossicles each with a ventral crest and one to seven cupules. Marginals articulated with each other laterally and were perforated by two types of canal. The peripheral skirt consists of larger frontal plates, one per cupule, and smaller imbricating roofing plates. It was flexible and could cover the entire cupule zone of the marginal ring. The cyclocystoid test resembled a tambourine, not a drum. Space for internal anatomy was extremely limited. The gut was straight and very short. Microphagous organic feeding was the only plausible method. We believe that food was gathered in the cupules, passed through the radial ducts of the marginals into covered radial channels of the disc and thence to the mouth. Locomotory tube feet were housed in the ventral sutural pores. We believe that cyclocystoids lived with the oral surface below, were mobile and gathered food from the sediment surface. The test grew in a complex fashion. Disc elements were added peripherally throughout growth. Marginal ossicles were added very quickly early in growth and the number remained fairly stable thereafter, but cupules and radial ducts continued to be added so that the number per ossicle increased. Cyclocystoids appeared in the Middle Ordovician of North America and are last recorded from the Middle Devonian of Europe. They were originally relatively rare but much more diverse than previously suspected. Analysis of gaps suggests that the fossil record of cyclocystoids at generic level is at least 36% incomplete. The class consists of a single family, the Cyclocystoididae, characterized by cupulebearing, perforate marginals and branched radii. Species with imperforate marginals (including the Middle Cambrian ‘ C .’ primotica Henderson & Shergold) are removed from the class. As restricted, the family includes the following genera: Cyclocystoides Salter & Billings, 1858; Narrawayella Foerste, 1920; Actinodiscus nov.; Apycnodiscus nov.; Diastocycloides nov.; Polytryphocycloides nov.; Sievertsia nov. and Zygocycloides nov. Genera are distinguished on the marginal ossicles (which may be in contact or separated dorsally and may or may not have cupular tubercles) and on the presence or absence of interradii or dorsal interseptal plates. We accept 25 species, plus five left under open nomenclature. New species are Cyclocystoides latus, C. scammaphoris, C. tholicos, Diastocycloides stauromorphos, Polytryphocycloides grandis, Sievertsia , Zygocycloides marstoni (Salter ms.) and Z. variabilis .

A temperature-controlled physiological colour response in the grasshopper Kosciuscola Tristis Sjost. (Orthoptera: Acrididae)

1954 ◽  
Vol 2 (3) ◽  
pp. 309 ◽  
Author(s):  
KHL Key ◽  
MF Day
Keyword(s):  
Natural Habitat ◽  
Marked Change ◽  
Colour Change ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Distal Portion ◽  
Epidermal Cells ◽  
Dense Layer ◽  
Dark Phase ◽  
Thermoregulatory Function

The alpine grasshopper Kosciuscola tristis shows a physiological colour change under the control of temperature. Males are a bright greenish blue above about 25�C and a dull near-black below about 15�C. Intermediate shades are developed at intermediate temperatures. A similar, but less marked, change occurs in the female. The colour change in the male was studied with the aid of a special colour chart, which enabled quantitative ratings of colour to be made. The histology of the integument is described. In the pale phase a dense layer of highly refractive, very small granules occupies the distal portion of the cells of the epidermis; these are underlain by a layer of larger dark brown granules. In the dark phase the position of these layers is reversed and the nuclei are raised above the basement membrane, on which they rest in the pale phase. At intermediate colour shades the granules show transitional distributions. It is concluded that the colour change is brought about by the migration of the two types of granule in opposite directions within the epidermal cells. The ecology of K. tristis in its natural habitat is discussed. On clear days the insects become pale 2-3 hr after sunrise and begin to turn dark again during the late afternoon; the night is spent in the dark phase. The colour follows closely the temperature given by blackened thermometers, but at any given temperature it differs from the equilibrium colour developed when that temperature is maintained constant, because of the lag in accommodation to the continuously changing temperature in the field. It is suggested that the colour change may have a thermoregulatory function. Two undescribed species of Kosciuscola show similar colour changes, but these are confined to the face and ventral surface. The same two types of granule are present in the epidermal cells, including those of the dorsal surface, where they are distributed as in the pale phase of K. tristis at all temperatures.

The external sensory morphology of the legs and hairplate system of female Trichogramma minutum Riley (Hymenoptera: Trichogrammatidae)

1987 ◽  
Vol 232 (1268) ◽  
pp. 323-366 ◽  
Keyword(s):  
Body Size ◽  
Neck Region ◽  
Dorsal Surface ◽  
Parasitoid Wasp ◽  
Ventral Surface ◽  
Distal Portion ◽  
The Body ◽  
Single Pair ◽  
Campaniform Sensilla ◽  
Trichogramma Minutum

This work continues a comprehensive description of the external sensory morphology of the parasitoid wasp Trichogramma minutum . All sensilla and associated structures identified by electron microscopy are described. In addition, this study also includes the hairplates associated with the antennae and neck region. The majority of sensilla appear to be mechanosensory, and are either trichoid or campaniform in structure. Large, socketed setae (10–50 μm long) are found on all leg segments, but vary considerably in body size and shape, depending upon location. On the tibial and tarsal segments of the pro- and metathoracic legs some of the larger hairs have been modified to form antennal and wing combs. On both the meso- and metathoracic legs a distal tibial seta is greatly enlarged and functions as a socketed spur. The sensilla that compose the hairplates are relatively short (1–3 μm) and differ in socket morphology from the longer setae located elsewhere on the body surface. Hairplates occur on the dorsal surface of the trochanter at the coxatrochanteral joint, on the distal portion of the coxae, around the neck on the dorsal and ventral surfaces of the episternum, and the opening of the postocciput. The most complex arrangement of hairplates surrounds the distal portion of the scape, and comprises four separate groups of hairs. Hairplates are also located on the dorsal and lateral surfaces of the proximal end of the pedicellus. Nine to eleven campaniform sensilla are located on the trochanter of each leg. The proximal subdivision of the femur is equipped with six sensilla grouped together on the ventral surface. Three to five campaniform sensilla are clustered on the dorsal surface of the distal end of the tibia of each leg, and a single pair of sensilla is located at the distal end of the first tarsomere. All the leg campaniform sensilla are elliptical, and 1.5–2.5 μm long. The number, position and morphology of the sensilla was consistent between individuals. The structure and function of these sensory structures are discussed in relation to their role in walking, proprioceptive control of posture, and gravity detection. The scaling of sensilla to body size and homologies with larger insects are also examined, and the possible role of these structures in the detection and measurement of host curvature is considered.

Scanning electron microscopy of the integument of schistosoma rodhaini

1986 ◽  
Vol 44 ◽  
pp. 132-133
Author(s):  
P. Evers ◽  
C. Schutte ◽  
C. D. Dettman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Oral Sucker ◽  
Adult Male ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Sensory Receptors ◽  
East African ◽  
Dorsal Midline ◽  
Scanning Electron

S.rodhaini (Brumpt 1931) is a parasite of East African rodents which may possibly hybridize with the human schistosome S. mansoni. The adult male at maturity measures approximately 3mm long and possesses both oral and ventral suckers and a marked gynaecophoric canal. The oral sucker is surrounded by a ring of sensory receptors with a large number of inwardly-pointing spines set into deep sockets occupying the bulk of the ventral surface of the sucker. Numbers of scattered sensory receptors are found on both dorsal and ventral surfaces of the head (Fig. 1) together with two conspicuous rows of receptors situated symmetrically on each side of the midline. One row extends along the dorsal surface of the head midway between the dorsal midline and the lateral margin.

The larval stages of the celery fly (Acidia heraclei L.) and of the braconid Adelura apii (Curtis), with notes upon an associated parasitic yeast-like fungus

Parasitology ◽  
1943 ◽  
Vol 35 (1-2) ◽  
pp. 27-36 ◽  
Author(s):  
D. Keilin ◽  
P. Tate
Keyword(s):  
Dorsal Surface ◽  
Ventral Surface ◽  
Host Larva ◽  
Yeast Cells ◽  
Stage Larva ◽  
Normal Type ◽  
Abortive Infection ◽  
Unique Case ◽  
Larval Stages ◽  
Adult Females

The larval stages of the celery fly, Acidia heraclei, have been described, and it is shown that this larva agrees with other biontophagous dipterous larvae in having the pharynx devoid of ventral ridges. The transparency of the larvae permits the internal anatomy to be seen clearly in the living larva, and by this means the structure of the perispiracular glands is clearly revealed.The braconid Adelura apii occurs as a parasite of Acidia heraclei larvae, and its first. stage larva is described in detail. This larva is densely hairy, has a long, curved, hairy, tail-like appendage and, by the more rapid growth of the ventral surface, it develops a dorsal curvature which obscures the true orientation so that the true dorsal surface appears externally to be ventral. In these respects the first stage larva of Adelura apii resembles that of A. gahani described by de la Baume-Pluvinel. The later larval stages of A. apii, of which there are at least two, are naked, lack the tail-like appendage and do not differ from the normal type of parasitic hymenopterous larvae.A yeast-like fungus occurs as a parasite in the blood of Acidia heraclei larvae. It is always found associated with existing or abortive infection of the larvae with Adelura apii. Dense mycelial masses sometimes occur in the gut of A. apii pupae and are probably derived from the yeast cells parasitic in the host larvae. It is suggested that this is a unique case of a fungus parasitic in a host larva (Acidia heraclei) undergoing part of its development in a parasitic braconid (Adelura apii), adult females of which transmit the fungus to the host larva during oviposition.

A new species of Glyptothorax (Teleostei: Sisoridae) from the Brahmaputra River basin, Arunachal Pradesh, India

Zootaxa ◽  
2021 ◽  
Vol 5023 (2) ◽  
pp. 239-250
Author(s):  
LAISHRAM KOSYGIN ◽  
PRATIMA SINGH ◽  
SHIBANANDA RATH
Keyword(s):  
River Basin ◽  
Indian Subcontinent ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Northeast India ◽  
Arunachal Pradesh ◽  
Brahmaputra River ◽  
Body Depth ◽  
Pectoral Spine ◽  
Pelvic Fin

Glyptothorax rupiri, a new sisorid catfish, is described from the Brahmaputra River basin in Arunachal Pradesh, northeast India. It differs from its congeners in the Indian subcontinent by the following combination of characters: the presence of plicae on the ventral surface of the pectoral spine and first pelvic-fin ray; a posteriorly serrated dorsal-fin spine, its length 11.3–12.2% SL; body depth at anus 11.2–13.4% SL; a thoracic adhesive apparatus longer than broad, with a V-shaped median depression which opens posteriorly; an arrow-shaped anterior nuchal plate element; adipose-fin base length 10.9–12.6% SL; nasal barbel not reaching anterior orbital margin; 14–18 serrae on posterior margin of the pectoral-fin spine; body with two longitudinal pale-cream stripes; densely tuberculated skin; and the presence of numerous tubercles on the dorsal surface of pectoral and pelvic-fin rays.  

A New Delphinium-Infesting Aphid (Homoptera: Aphididae)

1958 ◽  
Vol 90 (11) ◽  
pp. 690-692 ◽  
Author(s):  
W. R. Richards
Keyword(s):  
Dorsal Surface ◽  
Ventral Surface ◽  
Apical Segment ◽  
Basal Diameter ◽  
Viviparous Female ◽  
Fourth Segment ◽  
Small Tubercle ◽  
Small Primary ◽  
Basal Portion ◽  
Large Primary

Apterous Viviparous FemaleHolotype.–Dorsum of head with six blunt or slightly clavate setae. Frontal tubercles well developed, smooth, diverging, each with one long, (blunt seta on dorsal surface and one or two on ventral surface. Antenna about as long as body, third segment expanded just distad of base to almost twice its basal diameter; 56 small, tubercle-like, secondary sensoria scattered along whole length of one third segment, 60 on other; one fourth segment with four secondary sensoria, the other with five; a single, large, primary sensorium near apex of each fifth segment, and one large one and five or six adjacent smaller ones near apices of basal portion of sixth segment; each small primary sensorium on sixth segment with a central papilla; all primary sensoria lacking marginal, cilia-like fimbriations. Antennal setae distinctly capitate and about equal in length to basal diameter of third segment. Lengths of antenna1 segments as follows: III, 0.85 mm.; IV, 0.4 mm.; V, 0.3 mm.; VI, 0.15-0.85 mm. Rostrum reaching slightly beyond middle coxae; apical segment 0.13 mm. long, with 17 slender pointed setae in addition to usual apical ones.

scholarly journals Tongue papillae morphology of brown-throated sloth Bradypus variegatus (SCHINZ, 1825)

2014 ◽  
Vol 66 (5) ◽  
pp. 1479-1486 ◽  
Author(s):  
D.M. Martins ◽  
L.L. Pinheiro ◽  
V.C. Ferreira ◽  
A.M. Costa ◽  
A.R. Lima ◽  
...  
Keyword(s):  
Dorsal Surface ◽  
Ventral Surface ◽  
Simple Type ◽  
Morphological Aspect ◽  
Fungiform Papilla ◽  
Wild Mammals ◽  
Deep Groove ◽  
Vallate Papillae ◽  
Filiform Papillae ◽  
Bradypus Variegatus

The Bradypusvariegatus inhabits the forests of South America and feeds from leaves, branches and sprouts from different plants. Due to its diet and the lack of literature on the morphological aspect of Xenarthras, five Bradypusvariegatus tongues from animals which died from natural causes were evaluated, and they came from Pará State Museum Emílio Goeldi and were donated to the Laboratory of Animal Morphological Research (LaPMA) from UFRA, for revealing the different types of papillae and epithelial-connective tissue. Macroscopically, the tongues presented elongated shape, rounded apex, body, root, median sulcus in the root's apex, and two vallate papillae. The mucous membrane of the tongue revealed a keratinized stratified pavement epithelium, while the ventral surface of the tongue was thin and smooth, not provided with any type of papillae. However, the dorsal surface of the tongue was irregular with the presence of three types of papillae: filiform, fungiform and vallate papillae. The filiform papillae found were of a simple type, presenting a rounded base, irregularly distributed with a larger concentration and development on the tongue's apex and body. The fungiform papilla showed a practically smooth surface with irregular format, with the presence of gustatory pores; these were found all over the dorsal surface, with larger concentration at the rostral part of the apex. Only two vallate papillae were observed disposed in the root of the tongue, surrounded by a deep groove, and revealing several taste buds. The tongues from Bradypusvariegatus presented gustatory papillae similar to the ones described for other Xenarthras species and wild mammals.

scholarly journals The first data on the role of rhyncholites in the process of epibiota

2019 ◽  
pp. 5-9
Author(s):  
E. S. Gaponenko ◽  
M. A. Ulshin ◽  
V. N. Komarov
Keyword(s):  
Adult Worm ◽  
Dorsal Surface ◽  
Ventral Side ◽  
Ventral Surface ◽  
Clear Indication ◽  
Life Activity ◽  
Additional Food ◽  
Inner Surface ◽  
First Time

For the first time the role of rhyncholites in the process of epibiota has been figured out. Serpulidae inlay is detected in 39 rhyncholites of 979 specimens, representing 4% of the all studied material. This fact demonstrates that rhyncholites were used extremely rarely by encrusting species as a substrate. No other epibionts were found. Polychaetes were found in the genus Hadrocheilus (87%) and in the genus Akidocheilus. Size of the inlaid rhyncholites ranges from 7 to 23 mm. Serpulidae cover usually only the ventral side of rhyncholites, herewith, at 48,7% of the samples epibionts with different degrees of intensity are developed throughout the ventral surface, at 30,7% of the samples they are observed only on the ventral side of the hood and at 20,6% serpulidae are present only on the ventral surface of the arm. At four exemplars of the genus Hadrocheilus (10 % of the total amount) polychaetes are developed on the dorsal surface, but they are always and usually very wide developed on the ventral side of rhyncholites. No samples were found in which serpulidae were found only on the dorsal surface. Among the remains of polychaete worms, large and small tubes were identified and described. The presence of serpulidae on the handle of rhyncholites, that during the life of the cephalopod mollusk was located in a horny jaw, is a clear indication of the settlement’s epibionts on isolated skeletal structures of the already dead cephalopod. Cases when serpulidae are observed only on the ventral side of the hood in representatives of the genus Akidocheilus, suggest that planktonic trochophore – larvae of polychaetes can settle on the inner surface of the mandible of living ammonoids, where they turned into an adult worm. At the same time, polychaetes gained access not only to traditional prey, represented by various microscopic organisms, but also to additional food resources associated with the life activity of cephalopodas.

Morphology of Anomalocaris canadensis from the Burgess Shale

2014 ◽  
Vol 88 (1) ◽  
pp. 68-91 ◽  
Author(s):  
Allison C. Daley ◽  
Gregory D. Edgecombe
Keyword(s):  
Close Association ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
The Body ◽  
Body Region ◽  
Morphological Description ◽  
Burgess Shale ◽  
Oral Cone ◽  
Stem Lineage ◽  
Posterior Body Region

Recent description of the oral cone of Anomalocaris canadensis from the Burgess Shale (Cambrian Series 3, Stage 5) highlighted significant differences from published accounts of this iconic species, and prompts a new evaluation of its morphology as a whole. All known specimens of A. canadensis, including previously unpublished material, were examined with the aim of providing a cohesive morphological description of this stem lineage arthropod. In contrast to previous descriptions, the dorsal surface of the head is shown to be covered by a small, oval carapace in close association with paired stalked eyes, and the ventral surface bears only the triradial oral cone, with no evidence of a hypostome or an anterior sclerite. The frontal appendages reveal new details of the arthrodial membranes and a narrower cross-section in dorsal view than previously reconstructed. The posterior body region reveals a complex suite of digestive, respiratory, and locomotory characters that include a differentiated foregut and hindgut, a midgut with paired glands, gill-like setal blades, and evidence of muscle bundles and struts that presumably supported the swimming movement of the body flaps. The tail fan includes a central blade in addition to the previously described three pairs of lateral blades. Some of these structures have not been identified in other anomalocaridids, making Anomalocaris critical for understanding the functional morphology of the group as a whole and corroborating its arthropod affinities.

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