The life-cycles and larval development of some acanthocotylids (Monogenea) from Plymouth rays

Parasitology ◽  
1967 ◽  
Vol 57 (1) ◽  
pp. 157-167 ◽  
Author(s):  
G. C. Kearn
Keyword(s):  
Larval Development ◽  
Sexual Maturity ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
Life Cycles ◽  
Larval Body ◽  
Infective Larvae ◽  
Sea Bottom ◽  
Laboratory Facilities ◽  
Sexually Mature

Acanthocotylid (monogenean) parasites inhabit the skin of rays, and the lack of cilia on the infective larvae of these parasites may be an adaptation to the host's bottom-living habits.Freshly hatched larvae must remain on the sea-bottom until a ray settles on top of them, when the larvae then have the opportunity to attach themselves to the host's ventral surface. Acanthocotyle lobianchi, which infects Raia montagui and R. clavata at Plymouth, becomes sexually mature on the host's ventral surface and rarely wanders from it, but A. elegans, which is found on R. clavata only, migrates to the dorsal surface of the host before reaching sexual maturity.The larvae of acanthocotylids use their haptoral hooklets to attach themselves to the host's epidermis, but as the parasites increase in size the load on these hooks becomes acute. This load is relieved not as in other monogeneans by the development of hamuli but by the transformation of the posterior third of the larval body into an accessory ‘pseudohaptor’.I am obliged to the Director and Staff of the Plymouth Laboratory for laboratory facilities and to Mr J. E. Green for his interest and help on many occasions.

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.

scholarly journals Influence of temperature on the larval development of the edible crab, Cancer pagurus

2009 ◽  
Vol 89 (4) ◽  
pp. 753-759 ◽  
Author(s):  
Monika Weiss ◽  
Sven Thatje ◽  
Olaf Heilmayer ◽  
Klaus Anger ◽  
Thomas Brey ◽  
...  
Keyword(s):  
Larval Development ◽  
Body Mass ◽  
Large Scale ◽  
Citrate Synthase ◽  
C:N Ratio ◽  
Intraspecific Variability ◽  
Larval Body ◽  
Influence Of Temperature ◽  
Cancer Pagurus ◽  
Influence Of Temperature On

The influence of temperature on larval survival and development was studied in the edible crab, Cancer pagurus, from a population off the island of Helgoland, North Sea. In rearing experiments conducted at six different temperatures (6°, 10°, 14°, 15°, 18° and 24°C), zoeal development was only completed at 14° and 15°C. Instar duration of the Zoea I was negatively correlated with temperature. A model relating larval body mass to temperature and developmental time suggests that successful larval development is possible within a narrow temperature range (14° ± 3°C) only. This temperature optimum coincides with the highest citrate synthase activity found at 14°C. A comparison for intraspecific variability among freshly hatched zoeae from different females (CW 13–17 cm, N = 8) revealed that both body mass and elemental composition varied significantly. Initial larval dry weight ranged from 12.1 to 17.9 μg/individual, the carbon content from 4.6 to 5.8 μg/individual, nitrogen from 1.1 to 1.3 μg/individual, and the C:N ratio from 4.1 to 4.4. A narrow larval temperature tolerance range of C. pagurus as well as the indication of intraspecific variability in female energy allocation into eggs may indicate a potential vulnerability of this species to climate change. Large-scale studies on the ecological and physiological resilience potential of this commercially fished predator are needed.

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.

Exteroceptive Factors, Sexual Maturation and Reproduction in the Female Rat

1979 ◽  
Vol 13 (3) ◽  
pp. 283-286 ◽  
Author(s):  
M. L. Norris ◽  
C. E. Adams
Keyword(s):  
Reproductive Performance ◽  
Sexual Maturation ◽  
Sexual Maturity ◽  
Mature Male ◽  
Female Rat ◽  
Vaginal Opening ◽  
Sexually Mature

Summary Keeping a sexually mature male with a weanling female rat advanced neither the time of vaginal opening nor that of 1st oestrus. In 2 of 3 experiments females kept singly after weaning reached sexual maturity significantly earlier than did grouped females. The reproductive performance of females mated at 1st oestrus was not significantly different from that of older primiparae. 26 rats gave birth to an average of 9·3 young at 59·5 days of age, and 22 of them reared 96% of the young to weaning.

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.

Memoirs: The Loxosomatidae of the Plymouth Area, including L. obesum sp. nov

1932 ◽  
Vol s2-75 (298) ◽  
pp. 321-391
Author(s):  
DAPHNE ATKINS
Keyword(s):  
New Species ◽  
Small Group ◽  
Average Length ◽  
Dorsal Surface ◽  
Valid Species ◽  
Sense Organs ◽  
Small Disc ◽  
Longitudinal Muscles ◽  
Sexually Mature ◽  
A New Species

Four known species of Loxosoma, namely, L. phascolosomatum Vogt, L. crassicauda Salensky, L. singulare Keferstein, and L. claviforme Hincks, and a new species L. obesum are found in the Plymouth region, and are described. L. phascolosomatum is found on Phascolosoma vulgare, and in addition on two molluscs, Lepton clarkiae and Mysella bidentata from the burrows of Phascolosoma (pellucidum) elongatum from the Salcombe Estuary. L. crassicauda lives in the tanks in the Laboratory. Its average length is 1.4 mm. Between March 1929 and February 1930 males only were found: no ova were seen. L. singulare.--Occurs on Aphrodite aculeata; it varies between 0.18 and 0.8 mm. in length. In females carrying embryos the vestibule has two diverticula, one on either side of the rectum. L. claviforme.--It is considered a valid species, and may be distinguished from L. singulare by: (1) its greater size and length of stalk, (2) greater number of tentacles (commonly twelve), (3) position of the budding zone, and (4) the presence of paired sense-organs. Its average length is about 0.8 mm. It occurs on Hermione hystrix. A small group of Loxosoma, found on Aphrodite aculeata, were intermediate in form between L. singulare and L. claviforme, and were peculiar in retaining a number of their buds. The sex of such buds in several instances differed from that of the parent. L. obesum sp. nov. is found on the dorsal surface of Aphrodite aculeata. It may reach a length of 2.4 mm.; average individuals are rather more than 1.0 mm. in length. The lophophore is small, and bears almost invariably eight tentacles. Longitudinal muscles only are present in the stalk, which ends in a small disc of attachment. A foot-gland is present in the bud, and is frequently preserved as a vestige in the adult. The buds are near the lophophore, and may be as many as six on either side. The larva resembles that of L. singulare. Two main forms may be distinguished, differing in shape of the calyx and development of the stomach. The ovary may contain six well-developed ova on either side, and the vestibule twenty-six embryos. With one exception, females greatly exceeded males in number, and it is probable that the male becomes sexually mature at a smaller size than does the female.

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