Marginal Papillae Research Articles

A revision of Monocotyle Taschenberg, 1878 (Monogenea: Monocotylidae) with descriptions of three new species from Australia

Monocotyle is revised and three new species are proposed. Monocotyle corali sp. nov. is described from the gills of the cowtail ray, Pastinachus sephen (Forsskål) (Dasyatididae), and is distinguished from other members of Monocotyle by the large hamuli with a distinct tail on the guard and by the male copulatory organ with three loops and a wing-like accessory piece at the distal end. Monocotyle jordani sp. nov. from the gills of the southern eagle ray, Myliobatis australis Macleay (Myliobatididae), is differentiated by the male copulatory organ with a large, unique accessory piece. Monocotyle youngi sp. nov., from the gills of Himantura fai Jordan and Seale (Dasyatididae), has marginal haptoral papillae armed with 12 to 15 sclerites, a male copulatory organ with 20 loops and a unique accessory piece at the distal end. Monocotyle trygoni (Venkatanarsaiah and Kulkarni, 1980) Timofeeva, 1985 is synonymized with M. spirophallus Tripathi, 1959 and M. spirophallus is redescribed fully. There are now 16 valid species of Monocotyle and a key to species is presented. Additional data and illustrations of important taxonomic characters are provided. The developmental sequence of the male copulatory organ of M. spiremae Measures, Beverley-Burton and Williams, 1990 from juvenile to adult is described. The anterior glands and the type of secretion they contain are also documented for several species of Monocotyle.

Morphology and development of the haptors among the Monocotylidae (Monogenea)

Monocotylid monogeneans inhabit a wide diversity of sites on their chondrichthyan hosts including the skin, gills, nasal fossae, urogenital system and coelom. The large variation in the morphology of the haptor appears to reflect this diversity in attachment sites. We demonstrate that the complexity of the haptor can be related to the habitat of the parasite. Generally, those parasites which live in habitats subject to strong water currents such as the gills and dorsal skin surface have more complex haptors than those in environments exposed to weaker or no water currents including the nasal fossae, urogenital system and body cavity. However, there can be considerable variation in haptoral components, even among congeners, living on the ‘gills’ of their hosts. The microhabitat was determined for Monocotyle helicophallus and M. spiremae, both from the gills of the pink whipray, Himantura fai, and M. corali from the gills of the cowtail ray, Pastinachus sephen. We demonstrate that differences in the morphology of the hamuli and the number and morphology of septal sclerites and marginal papillae among these species of Monocotyle can be related directly to their microhabitat. It also appears that different haptoral structures are important for attachment to the host at different stages in the development of the parasite, based on studies on the development and distribution of Neoheterocotyle rhinobatidis from the gills of the common shovelnose ray Rhinobatos typus.

Intraepithelial nerve endings in the lingual marginal papillae of newborn piglets

The structure and occurrence of nerve fibres and nerve terminals in the lingual marginal papillae of newborn piglets are investigated by means of the osmium-zinc-iodate method and by transmission-electron microscopy. Subepithelial nerve fibres primarily accompany the blood vessels. They cross the epithelium with an almost vertical course to terminate in the stratum superficiale or the stratum corneum. Due to rows of varicosities, the axons look like a 'string of pearls'. As a result of the superficial localization and the typical ultrastructure, they seem to have a sensory function. Therefore, the papillae marginales are considered to function as mechanoreceptors.

Architektur und Feinstruktur der terminalen Blutgefäße der Zungenrandpapillen neugeborener Ferkel

The vascular architecture of the marginal papillae of the tongue was examined in one to five day old piglets by means of light and transmission electron microscopy and scanning microscopy of vascular corrosion casts. The marginal papillae of the tongue exhibit a "rope ladder-like" principle of blood supply. Every papilla contains one ascending arteriole, which branches into single capillary loops each supplying a protrusion of the multiply branched base of the capillary body. The transition of the arteriole takes place on the tip of the papilla. Subsequently the capillary loops converge onto this venule. Precapillary sphincters are observed at the origin of the capillary loops. This type of vessel arrangement offers the opportunity to use the capillary system at maximum efficiency, thus allowing an erection of the papillae marginales during the process of suckling.

Oral disc muscles of anuran tadpoles.

The presence and configurations of the small, extrinsic muscle fibers of the M. mandibulolabialis superior in the upper labium and the M. inferior in the lower labium are described for 24 species in 9 families. Although several species possess only the M. inferior, or both the M. inferior and superior, none has only the M. superior. Some species without tooth rows possess the M. inferior, and microhylid tadpoles have a single-stranded muscle different than the M. mandibulolabialis in each oral flap. The extrinsic oral muscles insert near the bottom of the inter-row valleys behind each tooth ridge and the bases of marginal papillae lateral to the ends of tooth rows. Muscles do not extend to marginal papillae beyond the most distal row of teeth. Muscle contraction is presumed to rotate the teeth distally so that they contact the substrate at the proper working angle. This action probably occurs at full extension of the oral disc just before disc closure starts.

Two lotic tadpoles from the Andes of southern Peru:Hyla armataandBufo veraguensis, with notes on the call ofHyla armata(Amphibia: Anura: Hylidae and Bufonidae)

The tadpoles of Hyla armata (Hylidae) and Bufo veraguensis (Bufonidae) from the Amazonian slopes of the Andes in southern Peru and Bolivia are described. These tadpoles, collected from streams draining the Cordillera Oriental in southern Peru, have modifications reflecting adaptations to stream life. These include, in Hyla armata, an enlarged oral disc with numerous labial tooth rows and complete marginal papillae and, in Bufo veraguensis, a belly sucker, unique within the genus but similar to the more fully‐developed sucker of Atelopus tadpoles. In addition, Bufo veraguensis tadpoles are unusual for Bufo in having a dextral vent, high density of labial teeth with no unbroken rows, and small external nares. The morphology of the tadpoles of Hyla armata and Bufo veraguensis is as yet uninformative regarding the relationships to these two unusual frogs. The advertisement call of Hyla armata consists of a single, high‐pitched note with a dominant frequency of 4.7 KHz.

Comparison of a Pharyngeal Filtering Apparatus in Seven Species of the Herbivorous Cyprinid Genus, Hybognathus (Pisces: Cyprinidae)

In all seven species of the herbivorous cyprinid genus Hybognathus, pharyngeal taste buds or papillae are arranged in a pattern that suggests a filtering apparatus for trapping diatoms and other small food items. The dorsal pharynx has a patch of small papillae that grades smoothly into larger, posterior buds. Ventrally, prominent transverse ridges cross the first, second, and third gill arches, joining anterior gill rakers to those on the posterior border of the arch. Proximally, the ridges merge into V-shaped flaps covering the basibranchials. The largest of these, termed the major comb, is associated with the first gill arch, and typically bears marginal and surface papillae. The minor comb, associated with the second arch, is smaller and bears marginal papillae. Proximal gill rakers of the second arch, located between the major and minor combs, have rows of papillae, and merge into a central, random patch of papillae. None of the 40 other nearctic cyprinid species surveyed, including Dionda episcopa, D. diaboli, and D. erimyzonops, has comparable pharyngeal modifications. Six counted variables and one measurement, major comb width, were used to make intra- and interspecific comparisons. Hybognathus hankinsoni has consistently low values for counted variables. Hybognathus nuchalis has high values for counted variables and is most similar to H. argyritis. Hybognathus placitus is most similar to H. amarus. Hybognathus hayi is the most distinct species in the genus, but is similar to H. regius in two variables including major comb width. Discriminant analysis classified 92.02% of specimens correctly, indicating that the variation observed in these structures is probably species-specific.

Sequence of ontogenetic development and atrophy of the oral apparatus of six anuran tadpoles.

The development of the oral structures of six species of anuran tadpoles with four different types of mouth parts and the metamorphic atrophy of these structures in two species with different mouth parts are described. The oral labia of typical tadpoles, oral flaps of microhylids, and lateral oral folds of Rhinophrynus are assumed to be homologous. We also suggest that the barbels of the tadpoles of Rhinophrynus are homologs of the marginal papillae of species with an oral disc. Developmental patterns and sequences of the oral structures of all tadpoles examined follow a common pattern: stomodeal invagination, oral pad development, jaw sheeth delimitation, tooth row ridge development, jaw sheath keratinization, and labial tooth keratinization. Developmental patterns remain constant, while interspecific differences are apparent because of truncations of ontogeny at specific stages. Metamorphic atrophy of oral structures occurs roughly in the reverse order of development, although the procedure is rapid and more haphazard than development.

THE ECOLOGICAL ROLE OF DEFENSIVE SECRETIONS IN THE INTERTIDAL PULMONATEONCHIDELLA BOREALIS

Repugnatorial glands located in the marginal papillae of the intertidal ochidiid pulmonate Onchidella borealis secrete a viscous fluid in response to mechanical or chemical stimulation. In laboratory encounters, this fluid repels intertidal predatory asteroids, particularly Leptasterias hexactis, but not predatory gastropods, polyclad turbellarians, nemerteans, or fishes. Intertidal crabs consume dead O. borealis readily, but seldom consume living individuals capable of firing their glands. The vertical range of O. borealis overlaps that of L. hexactis, whereas limpets that are vulnerable to predation by the sea stars generally live higher on the shore. On a small scale, O. borealis and L. hexactis occupy similar microhabitats (e.g., crevices, algal holdfasts), but are seldom found together. Field and laboratory experiments suggest that this negative spatial correlation may result from expulsion of the sea stars by onchidiids.

A description of the times of appearance and regression of marginal lingual papillae in human fetuses and newborns.

Papillae, located along the anterolateral margin of the human tongue, were observed in fetal and newborn stages. The papillae appeared in the prenatal period and attained maximum development in the newborn. They had almost disappeared by the time of weaning. Although morphologically, the papillae may be considered to be a form of the filiform papillae, they differed from the filiform papillae in that they were temporary, localized at the anterolateral margin of the tongue, and larger in size. These papillae are homologous with those in certain land mammals and toothed whales, and may assist in sucking. Our findings on the times of appearance and regression of marginal papillae support this notion.

Cytochemical Nature and Fine Structure of the Gregarine Zeylanocystis burti Dissanaike, with Special Reference to Microfilaments, Microtubules and Movement

SYNOPSIS. The mature trophozoite of the acephaline gregarine Zeylanocystis burti Dissanaike, parasitic in the seminal vesicles of the Sri Lankan earthworm Pheretima peguana Rosa, was studied by cytochemical methods and by electron microscopy. Some observations were also made on gametocysts and oocysts.The trophozoite has a peculiar saucer shape, unlike other monocystid gregarines, and has marginal papillae with cytoplasmic hairs. Its fine structure conforms broadly to that of other gregarines, but differs with respect to its fibrillar organization and in some details of cytoplasmic organelle structure. The pellicle is composed of 2 parallel unit membranes elevated into a number of stumpy epicytary folds, more or less evenly distributed on both surfaces of the gregarine. Some of these are associated with adjacent accessory cells and may have a nutritive role. Bundles of fine microfilaments (5–6 nm) were detected both in the ectoplasm and deep in the endoplasm; these are possibly the main contractile elements (“myonemes”) involved in movement. Microtubules are larger (22–24 nm) and are found predominantly in papillae and cytoplasmic hairs, but extend also in small bundles beneath the pellicle—they appear to be more skeletal in nature. The significance of these findings is discussed in the light of recent work on the roles of microfilaments and microtubules in nonmuscle cells. Mitochondria are located superficially and have a complex organization. The endoplasmic reticulum is poorly developed, but ribosomes are abundant. Golgi lamellae‐like membranes and vesicles akin to lysosomes were observed. Typical paraglycogen granules were found together with blobs of lipid and glycogen. The nucleus had a wrinkled envelope, a homogeneous matrix, and a spherical nucleolus.A variety of staining reactions and cytochemical tests were carried out. The distribution of lipids, polysaccharides, nucleic acids, calcium, and melanin were studied. Succinate dehydrogenase was detected in mitochondria, thiamine pyrophosphatase in Golgi bodies, and acid phosphatase in lysosomes. Golgi structures were found to be chemically very complex.Gametocysts and oocysts were associated with extraneous cells which probably contribute to the formation of their walls. The gametocyst wall is thin and consists of 2 membranes of the unit type. The oocyst wall is thicker and composed of 2 chemically different layers. Telolysosomes were seen in the disorganized residual cytoplasm within gametocysts.

Characters of F 1 Hybrid Tadpoles between Six Species of Hyla

Pigment patterns, tooth row ratios, and oral papillae were studied in 13 hybrid crosses of six species of Hyla. Pigment patterns that appeared to be controlled by dominant genes include the interorbital iridophore pattern of Hyla avivoca tadpoles, the copper-red tail saddles of H. avivoca, the yellow crossband on the body of H. cinerea tadpoles, the preorbital stripe of H. cinerea and H. avivoca, the striped tail pattern of H. femoralis and the unique melanophore distribution on the tail fin of H. gratiosa. On the anterior third of the tail in H. gratiosa, the melanophores are fibrillar and on the posterior portion they are punctate. These characteristics appeared in every hybrid tadpole involving at least one parent with the trait. The length of the third lower tooth row was somewhat intermediate between the parents but favored the parent with the longer row; this was particularly evident in crosses involving short and long-rowed parents. Lateral submarginal papillae tended to be intermediate in the hybrids, indicating a polygenic mode of inheritance, whereas a double row of marginal papillae on the ventral midline of the oral disc appeared to be dominant over a single row. Reciprocal crosses showed no detectable differences in hybrid characters. Natural hybrids between H. cinerea and H. gratiosa were morphologically similar to laboratory hybrids involving these two parents.

ON THE LIGHT RECEPTIVE FUNCTION OF THE MARGINAL PAPILLÆ OF GONIONEMUS

On the oral or subumbrellar margin of the jellyfish Gonionemus2 there are somewhat spherical or cordate papillae, correspondingin number to the tentacles, and almost directly underneath the proximal ends of the tentacles. They are a bright translucent rust color with darker pigment lining the interior. The cavity is a continuationl or pouch from the circular canal, thus insuring abundant nourishment for them. To distinguish them from marginal bodies, by which name Ccelenterate writers generally designate the otocysts, these organs are called marginal papillae. Nutting3 calls them sense and Hargitt4 and Goto 5 refer to them as basal bulbs, Hargitt4 describing them as of brownish color delicately tinged with bright green. He also ascribes visual function to them.6 The beautiful green spots