Fine Structure of Cephalic Sense Organs in Meloidogyne incognita Males

Amphids, and the cephalic and labial papillae of Meloidogyne incognita males were examined in detail by electron microscopy. Each amphid basically consists of an amphidial gland, a nerve bundle and an amphidial duct. The gland is a broad microvillous organ with a narrow anterior process, which is closely associated with the amphidial duct. A posterior process of the gland contains secretory organelles and proceeds along the esophagus with the lateral cephalic nerve bundle. The nerve bundle penetrates the broad portion of the gland and, subsequently, individual nerve processes (dendrites) separate from one another, thus forming the sensilla pouch which is enveloped by the gland. Anterior to the pouch, the dendrites converge as they enter and eventually terminate in the amphidial duct. The external opening of the duct is a broad slit which separates the cheek, the outermost part of the lateral lip, from the remainder of the lip region. M. incognita males have six inner labial papillae and four outer cephalic papillae which are each innervated by two and one cilia, respectively. In labial papillae, the cilia appear to terminate at the base of a pore opening, whereas in cephalic papillae each cilium terminates beneath the labial cuticle.     

Ultrastructure of Gonionchus australis (Xyalidae,Nematoda)

Observations are reported on the ultrastructure of the buccal cavity, body cuticle, spermatids, spermatozoa, male genitalia, and caudal glands of Gonionchus australis. The buccal cuticle is a continuation of the pharyngeal cuticle. Anteriorly it is secreted by arcade tissue and overlaps the mouth rim; laterally it forms longitudinal tooth ridges. The non-annulated cephalic cuticle differs sharply from the remainder of the body wall cuticle. The cortical and basal zones become much thinner, while a largely structureless, lucent median zone expands to fill the bulk of the lips and lip flaps. Spermatids possess fibrous bodies, multimembrane organelles, mitochondria, and compact chromatin. The spermatozoa of G. australis resemble those of most other nematodes by the absence of the nuclear envelope and presence of fibrous bodies, mitochondria, and compact chromafin. The ejaculatory duct possesses microvilli. Two ejaculatory glands lie beside the duct. Two neurons are located within each spicule and each part of the paired gubernaculum. Caudal gland nuclei are large, with dispersed chromatin. The ducts of all three caudal glands are filled with secretory vesicles.     

Observations on the buccal capsule and associated glands of adult Bunostomum trigonocephalum (nematoda)

Wilfred M. and Lee D. L. 1981. Observations on the buccal capsule and associated glands of adult Bunostomum trigonocephalum (Nematoda). International Journal for Parasitology11: 485–492. The buccal capsule or stoma of Bunostomum trigonocephalum is a large, cuticular-lined structure. The head of the nematode lacks distinct lips and has a large ovoid mouth which is partly occluded by a pair of sub-ventral cuticular plates which arise from the wall of the buccal cavity. A pair of sub-ventral lancets or basal onchia are situated at the base of the buccal cavity and a dorsal tooth arises from the base of the buccal cavity and extends forwards to terminate just inside the mouth. A duct lies within this dorsal tooth and extends from the ampulla of the dorsal oesophageal gland at the base of the tooth to open on the dorsal side of the tooth just below its sharp tip. A pair of muscles extends from the dorsal surface of the oesophagus to the base of the buccal capsule and are thought to bring about jerking movements of the head. Non-specific esterase and small amounts of acid phosphatase were detected in the oesophageal glands. Non-specific esterase and cholinesterase were detected in the large amphidial glands but not in the excretory glands. The possible role of the various structures and enzymes during feeding is discussed.     

Fine Structure of the Head and Cervical Region of Ceramonema carinatum (Chromadorida: Ceramonematidae)

Structure of the head and cervical region of Ceramonema carinatum (Chromadorida: Ceramonematidae) was described from transmission electron microscopy of serial transverse and longitudinal sections of two females. An unbroken massive cortical layer encompasses the head, except where three thin liplets surround the mouth. A large flask-shaped buccal cavity, with simpler less dense cuticle identical with that of the pharynx, abuts the body cuticle just within the mouth. Myoepithelial ceils constituting the buccal and pharyngeal regions were described. Sixteen head sensilla, the amphids, and dorsal and ventral internal sensilla were identified and described, each with associated sheath and socket cells. Ultrasturcture of the head was compared with that of other nematodes. Arrangement of sensilla resembled that of Monhysterida and Rhabditida with some significant variations, such as prominent longitudinally arranged intracellular organelles containing many microtubules associated with the amphids. The buccal cavity was almost entirely pharyngeal in character. A well-developed system of structural fibrils and abundant hemidesmosomes were notable features.     

Structure of the Cuticle of Metadasynemoides cristatus (Chromadorida: Ceramonematidae)

Structure of the cuticle of Metadasynemoides cristatus (Chromadorida: Ceramonematidae) is examined by light, scanning, and transmission electron microscopy. The nematode has more than 600 annuli, and each annulus has eight cuticular plates. Eight longitudinal ridges, beginning on the cephalic capsule, extend the whole length of the body. Where a ridge traverses an annulus, it forms a complicated articulating structure of overlapping vanes. Within the electron-dense cortical layer, from which the cuticular plates are formed, there are spaces crossed by fine fibrillae, forming what have been termed "vacuoles" by light microscopists. There is an epicuticle and a continuous lucent basal layer. There appears to be no median layer. The cuticle lining of the esophagus and that forming the circum-oral ridge is of much simpler construction.     

Scanning Electron Microscopy of Second-Stage Juvenile Cephalic Morphology in Heterodera glycines Races

Scanning electron microscopy (SEM) was used to compare juvenile cephalic morphology of the five described races of Heterodera glycines. Races 1, 2, 3, and 4 were obtained in the United States and race 5 was obtained from Japan. Differences in the gross morphology o f labial discs; ventral, dorsal and lateral lips; amphidial apertures; and fissures on the labial disc o f some specimens were observed. There was considerable interracial and intraracial variation which precluded separation o f juveniles of H. glycines races by SEM.     

Teratological Development in the Cephalic Anatomy of the Nematode Romanomermis culicivorax

Adults of Romanomermis culicivorax obtained from mass cultures were examined by scanning and transmission electron microscopy to determine the organization of their anterior sense organs. The normal pattern apparently consists of two lateral amphids plus six cephalic papillae. Lateral cephalic papillae contain two sense organs, each with a cuticular pore, while subdorsal and subventral papillae have three sense organs, each with a cuticular pore. About 30% of females and 80% of males examined showed aberrant developments in these sense organs. Both cuticle and underlying cells (hypodermis and neurons) are affected; some sense organs are absent while others are incompletely formed. Few aberrant worms were found in a smaller collection of worms reared in lower population densities. Perhaps aberrant forms are examples of teratological development resulting from, or promoted by, conditions used for mass rearing of biological control agents.     

Aspects on the Ultrastructure of the Cephalic Region in Two Species of Acrobelinae (Nematoda,Cephalobidae)

The lip structures termed labial probolae, characteristic for the subfamily Acrobelinae, and the anterior sense organs have been studied by electron microscopy. The labial probolae consist of an amorphous tissue with denser strengthenings. They do not contain any sensory structures or musculature. The anterior sense organs consists of: (1) six inner labial sensilla, each with one receptor ending in a pore on a papilla; (2) six outer labial sensilla, each with one receptor ending in the cuticle; (3) four cephalic sensilla, each with two receptors, one ending in a pore on a papilla and the other in the cuticle; (4) two amphids, each with 12 sensory neurons basally; (5) accessory sensilla ventro-laterally. The combination of several chemoreceptive anterior sensilla and the morphological diversity of the labial probolae within the subfamily may aid in the utilization of different soil microhabitats.     

The setae of parasitic Liphyra brassolis butterfly larvae form a flexible armour for resisting attack by their ant hosts (Lycaenidae: Lepidoptera)

Caterpillars of the lycaenid butterfly, Liphyra brassolis, live inside the nests of arboreal weaver ants, Oecophylla smaragdina, and eat their brood. Observations of mature larvae suggest that they are impervious to relentless ant molestation, yet they lack sclerotized cuticular plates. We document a novel form of integumental defence that imparts protection from ant attack whilst maintaining the flexibility necessary to walk with a hydraulic skeleton. Analysis of the trunk integument and cuticular structures of early and late instars of L. brassolis using light microscopy, scanning electron microscopy, and histology revealed three new setae types (disc, clavate, and lanceolate), as well as three new cuticular structures (pored sockets, cuticular pores, and cuticular domes). The unique cuticle is covered with lanceolate setae, which act as endocuticular struts, and overlapping scale‐like sockets, which form a hard, flexible integument. The imperfect armour of the early‐instar larvae suggests that abundant, putatively secretory pores are likely to be homologous to pore cupola organs (PCOs) found in other lycaenid larvae and thus may exude semiochemicals to allay ant aggression. The importance of these pores presumably wanes as structural (setal) cuticular defenses are reinforced in later instars, when adult ants have been observed attacking caterpillars to no avail. The caterpillar's antennae are unusual and seem to be involved in manipulating ant larvae into the caterpillar's mouth. Behavioural observations indicate that the dexterity of these structures is associated with eating ants (myrmecophagy).     

Deep-sea nematodes (Nemata, Prochaetosomatinae): new taxa from hydrothermal vents and a polymetallic nodule formation of the Pacific (East Rise; North Fiji and Lau Basins; Clarion-Clipperton fracture zone)

Dinetia nycterobia gen. et sp. n. (Draconematidae, Prochaetosomatinae) is described from a hydrothermal site of the East Pacific Rise. The new genus is characterized by body annulation reaching lip region and including spiral amphids, cuticle not thickened in head region, cephalic adhesion tubes without expanded base located in cervical region, pharynx with terminal bulb provided with a thick cuticularized lumen wall, and posterior adhesion tubes with bell-shaped end. Dinetia nycterobia , the type species, is characterized by the number of cephalic adhesion tubes (19 in male, 15 in female) and of the 4 rows of posterior adhesion tubes (5 tubes lateral, 14–19 subventral in male, 10–15 lateral, 13–20 subventral in female) and the shape and size of the spicules. Cephalochaetosoma pacificum notium subsp. n. from the Fiji deep-sea closely resemble C. pacificum pacificum from Philippines deep-sea but differs in male by the number of sublateral posterior adhesion tubes, the shape and size of the spicules, the number of cloacal setae, the structure of the testis and in both sexes by the spiny cuticular ornamentation, the shorter labial setae and morphometric data. A new genus and new species of Draconematidae is provisionally described, based on the observation of juvenile specimens from the polymetallic nodule formation.     

Scanning electron microscopy of the labia of Baylisascaris procyonis (Nematoda)

The labial organization of adult Baylisascaris procyonis was studied by scanning electron microscopy, and found to be similar for males and females. The apical part of each lip was smooth, and the basal part reticulated. The dorsal lip possessed two dorsolateral double papillae and two internal labial papillae; the two subventral lips each had one ventrolateral double and one externolateral papilla, two internal labial papillae, and an amphid. The small papilla of each double set was dome-shaped and smooth, whereas the large papilla was broad and had a prominent central pore. The externolateral papillae had raised, highly sculptured surfaces with numerous slits and creases present. Amphids resembled those of previously studied nematodes. The internal labial papillae consisted of pits. Denticles arose as a single row from the apical edge of the inner labial surface, were usually evenly spaced, and pyramidal or conoidal in shape. They were typically unicuspid, but bicuspid denticles were occasionally seen. Denticle shape and size varied between specimens and on each specimen. A pit was seen in the cuticle in the central region of the denticular row of all lips. Several of these findings represent new information concerning ascaridoid nematodes.     

Fine Structure of Cephalic Sense Organs in Heterodera glycines Males

Cephalic sense organs of Heterodera glycines males were examined in detail by electron microscopy. Each amphid basically consists of an amphidial gland, a nerve bundle, and an amphidial duct. The amphidial gland consists of a microvillous region, and laterally is closely associated with a large secretory cell. The nerve bundle penetrates the microvillous region, and further anteriorly individual nerve processes (dendrites) separate from one another, thus forming a sensilla pouch which is enveloped by the microvillous region of the gland. Anterior to the pouch, the cilia-like dendrites converge as they enter and eventually terminate in the amphidial duct. Heterodera glvcines males have the innervation basis for a full complement of sixteen papillae, although surface manifestations are present for only six minute inner labial papillae. In addition, four outer labial and four cephalic receptors terminate beneath the surface, and another two dendrite pairs end further posteriorly beneath the basal plate of the cephalic framework. Papillary receptors which terminate beneath the surface are probably mechanoreceptive, whereas inner labial papillae have pore-like openings to the exterior and may be chemoreceptive. Amphids and papillae of H. glycines are fundamentally similar to those of Meloidogyne incognita, although certain striking differences exist.     

五种线虫头端顶面的扫描电镜观察

应用扫描电镜观察了弗氏旷口线虫、似血矛线虫、辐射食道口线虫、粗纹食道口线虫、哥伦比亚食道口线虫的头端顶面。对弗氏旷口线虫和似血矛线虫口囊内齿或口矛的形态,三种食道口线虫的叶冠、化感器和感觉乳突进行了描述。     

Scanning Electron Microscope Studies of Steinernema anomali Kozodoi, 1984

This paper presents SEM micrographs of portions of the male, female, and infective-stage juvenile of Steinernema anomali. Included are micrographs of the cephalic and caudal region, spicules, and gubernaculum of the male, the cephalic and vulval region of the female, and the cephalic region of the infective-stage juvenile. Males have six labial and four prominent cephalic papillae and small amphids. There are 11-14 pairs and one single genital papillae; of these, 6-9 pairs are preanal and subventral, one pair preanal, lateral, one pair adanal, and three pairs postanal. Spicules have a short head, a long blade, and a reduced shaft. The distal end is enlarged and bears a dorsal aperture. Gubernaculum much shorter than spicules; cuneus of gubernaculum short and bifurcate anteriorly. Females have six labial and four cephalic papillae and small amphids. Vulva with a thickened posterior lip. Infective juveniles have a smooth head, prominent amphids, and four cephalic papillae. Labial papillae, if present, are not evident.     

Larval Gnathostoma hispidum detected in the red banded odd-tooth snake, Dinodon rufozonatum rufozonatum, from China

A total of 205 larval gnathostomes were collected from 18 (22.5%) of 80 red banded odd-tooth snakes, Dinodon rufozonatum rufozonatum, which had been smuggled from China and confiscated at Customs in Busan, Republic of Korea. In order to identify the species, some of the larvae were observed by a light microscope and a scanning electron microscope (SEM). The larvae were 2.18 x 0.29 mm in average size, and had a pair of lips at the anterior end, a muscular esophagus, 2 pairs of cervical sacs, and brownish intestines. The head bulb was characteristically equipped with 4 rows of hooklets; the average number of hooklets in each respective row was 38.6, 40.5, 41.5, and 43.7. In SEM views, the mouth evidenced a pair of lateral lips of equal size in a half-moon shape. Each lip featured a couple of labial papillae and a small amphid located between the 2 papillae. The hooklets on the head bulb had single-pointed, posteriorly-curved tips. The cuticular spines were larger and more densely distributed on the anterior part of the body, and decreased gradually in size and number toward the posterior body. On the basis of these morphological characteristics, the larvae were identified as the third stage larvae of Gnathostoma hispidum.     

Surface ultrastructure of the advanced third-stage larvae of Gnathostoma nipponicum

The surface ultrastructure of advanced third-stage larvae (AL3) of Gnathostoma nipponicum was studied using scanning electron microscopy. The larvae were recovered from the grass snake Rhabdophis tigrina in the Republic of Korea. Parasites had a globular head bulb with a pair of lips at the anterior end and 2 labial papillae and an amphid on each lip. The head bulb was characteristically armed with 3 transverse rows of hooklets, averaging 36, 38, and 43 in number, increasing posteriorly. A total of 213-232 minute unidentate cuticular spines were present along the entire length of the larvae, forming the transverse striations. Two pairs of cervical papillae were located between the 8th and 12th transverse striations, and a pair of body papillae was seen laterally on the posterior third of the body. A pair of caudal phasmids was recognized near the posterior extremity. The surface ultrastructure of AL3 of G. nipponicum is unique compared with that of other species.     

Deep-sea nematodes from the Indian Ocean: new and known species of the family Comesomatidae

Twelve new and known species of the genera Sabatieria,Cervonema, Paramesonchium, Hopperia and Dorylaimopsis and one new genus, Kenyanema aredescribed from the Indian Ocean and S. pisinna Vitiello,1970 from the Mediterranean Sea. Sabatieria lucia sp. n.is characterised by short but distinct inner and setiformouter labial sensilla and long (4–5 µm or 30–33% hd)cephalic sensilla; S. conicauda Vitiello, 1970, ischaracterised by tiny inner and outer labial sensilla andsetiform cephalic ones and short and thick cylindrical tail;Sabatieria pisinna is characterised by short innerand outer labial sensilla, setiform (3µm long) cephalicsensilla, multispiral amphids with 3.25–3.5 turns and a tailwhich is conical in the anterior 2/3 and posterior 1/3cylindrical; Cervonema tenuicauda Schuurmans Stekhoven,1950, is characterised by anterior sensilla in twocircles which are equal in length (3µm long), multispiralamphids with 3–4 turns and located at 1.5 times hd from theanterior end, simple spicules one abd long and 6–7 fineprecloacal supplements; Cervonema minutus sp. n.characterised by an extremely attenuated anterior end,spiral amphids with 4–5 turns (80–90% cbd) and short,simple spicules (0.8 abd long); Cervonema gourbaulti sp.n. characterised by long (4–5 µm) labialand cephalic sensilla, spiral amphids with 5–6 turns(73–88% cbd) and an elongate crenate terminal pharyngealbulb; Paramesonchium mombasi sp. n. characterised bylong labial (5 µm) and cephalic (21 µm) sensilla thatare close together and wide amphids (80–90% cbd); Kenyanema monorchis gen. et sp. n. characterised bya head region narrower than the rest of the body, fourcephalic sensilla (3 µm long) and spiral amphids with1.5–2 turns; Hopperia indiana sp. n. characterised byshort conical anterior sensilla, arcuatespicules that have a velum and a gubernaculum with a longand sharp pointed apophysis; Dorylaimopsis coomansi sp.n. characterised by long (8–10µm) cephalic setae,cuticular punctation with lateral differention of irregularlyarranged dots at the pharyngeal region and 1–3longitudinal rows of dots posterior of the pharynx; spiculeswith a unique shape; Dorylaimopsis gerardi sp. n.characterised by short setiform labial and long (6–7 µm)cephalic sensilla, punctated cuticle with lateraldifferentiation of irregularly arranged dots at firstthen three or four irregularly arranged longitudinal rows atthe pharyngeal and tail regions and two regularly arrangedlongitudinal rows of dots on the rest of the body, aconico-cylindrical tail with a distinctly swollen tip;Dorylaimopsis variabilis sp. n. is characterised byshort labial and setiform cephalic sensilla (33–58% hd),multispiral amphids with three turns, cuticular punctationswith lateral differentiation of three longitudinalrows at the pharyngeal and tail regions and two longitudinalrows on the rest of the body, spicules that are thin andslightly arcuate. The position of S. pisinna accordingto the grouping of Platt, 1985 of Sabatieriaspp. is also discussed. Kenyanema monorchis representsthe first monorchic species in the family.     

Ultrastructure of aesthetasc innervation and external morphology of the lateral antennule setae of the spiny lobster Panulirus interruptus (Randall)

Summary Six types of setae and one type of cuticular depression were examined on the lateral antennule of the spiny lobster Panulirus interruptus using scanning electron microscopy. The organization and ultrastructure of the innervation of the most numerous setal type, the aesthetasc, were investigated using light-and transmission electron microscopy.Each aesthetasc is innervated by approximately 300 bipolar neurons whose sensory dendrites penetrate the hair and extend toward the tip, and whose axons project towards the central nervous system. The neuronal somata and two types of glia form a cluster within the antennular lumen. The inner sheath-cell somata encircle the dendritic tract distal to the sensory somata. These cells appear to extend distal processes which wrap the dendritic tract to the base of the aesthetasc. Elongate outer sheath cells are interposed between the glia-wrapped dendritic tract and the hypodermis which underlies the antennule cuticle. A continuous investment of neural lamella separates the hypodermis, the entire cluster of somata, and sensillar nerve from the antennule lumen. The organization of the neuronal somata and their association with outer and inner sheath cells in this marine species appear similar to those of crustaceans from freshwater and terrestrial habitats.     

Meloidogyne haplanaria n. sp. (Nematoda: Meloidogynidae), a Root-knot Nematode Parasitizing Peanut in Texas

Meloidogyne haplanaria n. sp. is described and illustrated from specimens parasitizing peanut in Texas. The perineal pattern of the female is rounded to oval with a dorsal arch that is high and rounded except for striae near the vulva, which are low with rounded shoulders. The striae are distinctly forked in the lateral field, and punctations often occur as a small group near the tail tip and singly within the whole perineal pattern. The female stylet is 13-16 µm long and has broad, distinctly set-off knobs. The excretory pore opens 40-118 µm from the head, approximately halfway between the anterior end and the metacorpus. Males are 1.2-2.4 µm in length and have a high, wide head cap that slopes posteriorly. The labial disc and medial lips are partially fused to form an elongated lip structure. In some specimens the labial disk is distinctly separated from the lips by a groove. The stylet is 17-22 µm long and has wide knobs that are rounded and distinctly set off from the shaft. Mean second-stage juvenile length is 419 µm. The head region is not annulated, and the large labial disc and crescent-shaped medial lips are fused to form a dumbbell-shaped head cap. The stylet is 9-12 µm long and has rounded, posteriorly sloping knobs. The slender tail, 58-74 µm long, has a distinct, inflated rectum and a slightly rounded tip. The hyaline tail terminus is 11-16 µm long. The isozyme phenotypes for esterase and malic dehydrogenase do not correspond to any other recognized Meloidogyne species. Tomato and peanut are good hosts; corn and wheat are very poor hosts; and cotton, tobacco, pepper, and watermelon are nonhosts.