Paralineopsis taki gen. et sp. nov., a littoral heteronemertean from Japan,provided with special proboscideal,circulatory and sensory organs of significance to nemertean systematics

Some morphological features with major systematic significance are recorded in the heteronemertean Paralineopsis taki gen. et sp. nov. from Onomichi, Japan as follows: horizontal band of specialized epithelium extends from near apex to the opening of the cerebral organ canal on either side of the head; precerebral region filled with gelatinous (hyaline) connective tissue in which longitudinal muscles are absent; body wall muscles do not accompany rhynchodaeal invagination; rhynchodaeum initially only epidermal; inner longitudinal muscles of ventral wall of cephalic blood lacuna become intimately associated with rhynchodaeum forming a dorsal saddle over it; cerebral organs do not penetrate inner longitudinal muscles, and do not contact blood vascular system; proboscideal diaphragm post-cerebral; outer longitudinal muscles absent throughout body; longitudinal muscles of proboscis derived from inner longitudinal musculature. The systematic relationship of P. taki and Paralineus elisabethae (Schütz, 1911) from Villefranche, France is discussed.     

The Stylet Apparatus of Monostiliferous Hoplonemerteans

This paper compares the ultrastructure, development, and functionalmorphology of the stylet apparatus in monostiliferous hoplonemerteans(Phylum Nemertea: Class Enopla). The apparatus occurs in themiddle region of the worm's eversible proboscis and consistsof two main components: 1) a central stylet that is attachedto an anchoring device called the basis; and 2) reserve styletsacs that contain nail-like reserve stylets. The knob-shapedproximal piece of the central stylet is embedded in the anteriorend of the basis, and the tapered shaft of the stylet is directedanteriorly. When the proboscis is fully everted, the centralstylet is used to stab such prey as polychaete worms and smallcrustaceans. Wounds inflicted by the stylet allow the introductionof paralytic neurotoxins that are produced by glandular cellsin the epithelial lining of the proboscis. Reservestylets formintracellularly within the reserve stylet sacs and serve toreplace the central stylet when it becomes lost or damaged.Fully developed stylets typically measure 50 to 250 µmin length and comprise an organic core surrounded by an inorganiccortex that contains calcium phosphate. In juvenile worms thatare four days to several weeks old, reserve stylets are assembledbefore other components of the stylet apparatus are fully differentiated.Subsequently, a reserve stylet is transferred to the centralregion of the proboscis and placed on the basis. Stages in theprocess of stylet attachment are described, and the probablesequence by which the stylet apparatus co-evolved with toxin-producingcells is discussed.     

Proboscis sensilla in Vanessa cardui (Nymphalidae, Lepidoptera): functional morphology and significance in flower-probing

 Morphology and distribution of the proboscis sensilla in Vanessa cardui have been investigated in order to contribute to the understanding of flower-probing behaviour in butterflies. The proboscis has a bend region approximately one-third of the length from the base. A short tip region is characterized by rows of intake slits leading into the food canal. Along the dorsal, lateral and ventral sides of the proboscis, sensilla trichodea, sensilla basiconica and sensilla styloconica are distributed in varying patterns depending on their distance from the b ase. The medial food canal bears one longitudinal row of sensilla basiconica only. The bristle-shaped sensilla trichodea are longer in the proximal region of the proboscis and become gradually shorter towards the tip. They are most frequent in number near to the bend region and near the beginning of the tip region. Sensilla basiconica arranged in longitudinal rows increase in number the more distal they are on the proboscis. The tip region is characterized by rows of sensilla styloconica on the dorsal side whereas the sensilla trichodea are mostly restricted to the ventral side. The ultrastructure suggests that the aporous sensilla trichodea function as mechanosensilla while the uniporous sensilla basiconica act as contact chemosensilla. The sensilla styloconica are regarded as bimodal contact chemo/mechanosensilla since their sensory cones are equipped with a single terminal pore and a tubular body at the base. The mouthpart sensilla appear to provide tactile cues on the positioning of the proboscis and on the degree of its insertion into a floral tube. Furthermore, they receive chemical stimuli on the availability of nectar and on the immersion status of the food canal. Accepted: 12 September 1997     

On the hoplonemertean Sagaminemertes nagaiensis (Iwata, 1957), with consideration of its systematics

Summary The polystiliferous hoplonemertean Sagaminemertes nagaiensis (Iwata, 1957) has been redescribed.A distinct pre-cerebral region is wanting. The rhynchocoel opens directly at the tip of the head, whilst the mouth opens seperately below the ventral commissure of the brain which is situated at the anterior end of the head. The dorsal ganglia are well developed and extend posteriorly far behind the ventral ganglia. The cerebral sense organs are situated behind the brain and possess posterior ciliated canals. Cephalic glands are poorly represented, but ocelli are well developed. The sickle-shaped basis of the proboscis bears about 20 central stylets. The caecal appendages of the rhynchocoel are arranged pseudometamerically throughout the body. The foregut is straight, consisting of mouth, oesophagus, stomach and pylorus. Intestinal caeca and lateral diverticula are present. The cephalic lacunae have no anterior anastomosis. A cerebral lacuna is present, there is a rhynchocoel vessel, but transverse vessels are absent. The protonephridia extend throughout the foregut region. Mature spermatogonia are well developed.A systematic discussion of Sagaminemertes nagaiensis suggests that it is taxonomically close to Siboganemertes weberi in the archireptantic family Siboganemertidae.     

Locomotory and other movements of the proboscis of Bonellia viridis (Echiura, Bonelliidae)

An account is given of the various movements of the proboscis of Bonellia viridis. When at rest, the proboscis is coiled up in front of the trunk. The proboscis lobes progress with a velocity of the order of 1 mm/sec by means of powerful cilia situated on the dorsal surface of the leading edge. The lobes passively drag and uncoil the stem of the proboscis which is further uncoiled by muscular contractions taking place along the uncoiled part of the stem. Proboscis retraction takes place by means of contraction of the numerous longitudinal muscle strands of the stem. The terminal lobes can attach to the substrate and pull the trunk by contraction of the proboscis stem. The proboscis often ties itself into a knot which it can untie.     

Organisation of the praesoma in Acanthocephalus anguillae (Acanthocephala, Palaeacanthocephala) with special reference to the muscular system

The organisation of the praesoma in the parasite Acanthocephalus anguillae was studied on the light and electron microscopic level, with emphasis on the morphology of the musculature. The study was compiled to add new data to the ground pattern of the Acanthocephala for analysis of the phylogenetic relationships within the Gnathifera. In A. anguillae the praesomal epidermis and lemnisci form a coherent syncytium, separated from the epidermis of the trunk. Hooks are seen to be derivatives of the subepidermal basal lamina and are covered by the praesomal epidermis. The praesomal circular body wall musculature forms a network of anastomosing muscle fibres that lines the proboscis; a praesomal longitudinal body wall musculature does not exist. The truncal circular and longitudinal body wall musculature rise up to the praesomal proboscis. The unpaired proboscis retractor, consisting of longitudinal circomyar fibres, forms an outer and an inner concentric tube; the latter extends through the entire praesoma and penetrates the receptacle wall. The sack-like receptacle is surrounded by a receptacle constrictor. The nervous system of the praesoma consists of a prominent cerebral ganglion, three nerves which extend anteriorly, ramify and end within the praesomal musculature, and two strong lateral posterior nerves. A. anguillae lacks an apical organ, lateral organs and a support cell. Many of the features present in the praesoma of A. anguillae can be assumed as ground-pattern characteristics of the Acanthocephala. Accepted: 22 January 2001     

Description and morphological variability of <Emphasis Type="Italic">Neoechinorhynchus beringianus</Emphasis> n. sp. (Acanthocephala: Neoechinorhynchidae) from north-eastern Asia

Neoechinorhynchus beringianus sp. n. is described from Pungitius pungitius L. in north-eastern Russia. Since 1986, when it was first found, it was reported as 'N. pungitius Dechtiar, 1971'. However, this new species differs from the latter in having an egg shell without a prolongation of the fertilisation membrane, a larger proboscis and proboscis hooks, a subterminal position of the female genital pore and a more slender trunk, and it occurs in a different site in the intestine. N. beringianus has a small, stout body with an asymmetrical position of the proboscis, which is located ventrally to and at an angle with the longitudinal axis of the body. The proboscis is wider than long, the hooks are of equal size in each circle but diminish in size posteriorly, whereas the lemnisci are subequal in length. It differs from those species of Neoechinorhynchus Stiles & Hassall, 1905 with somewhat similar characteristics in body length, proboscis size and proportions, proboscis hook lengths, egg size, size-ratio of the cement gland and testes, and the number of giant nuclei in the tegument and lemnisci. In different geographical populations of the new species, the sizes of both the proboscis and proboscis hooks exhibit some variation.     

A new mangrove-dwelling nemertean from China

Nemertean specimens were collected from the mangrove zone in the estuary of Jiulong Jiang River. Histological studies revealed that they belong to genus Pantinonemertes but differed from the known taxa of the genus. In the present paper they are described as a new species, Pantinonemertes fujianensis sp. nov. The immature specimens, with the body rounded anteriorly and somewhat dorso-ventrally flattened in intestinal region, measured about 85–120 mm long and 1.5–2.0 mm wide. Dark pigment is concentrated along the mid-dorsal line to form a longitudinal stripe that extends for most of the body length. The head possesses a pair of horizontal longitudinal furrows, a pair of oblique lateral furrows and four eyes. A precerebral septum is absent. The proboscis is well developed and possesses 19 large proboscis nerves. The frontal organ is a well-developed tubular structure, with the epithelium regionally differentiated. Cephalic glands are extensive, consisting of faintly stained small glands that open into the frontal organ, large blocks of clear gland and orange-staining glands (stained with Mallory triple method) that open through the ducts penetrating the body wall. The excretory system consists of numerous binucleate flame cells especially in the anterior body region, each flame cell possesses 7–9 transverse cuticular support rings. Excretory tubules either open to exterior via the efferent ducts penetrating the body wall or open into the frontal organ. Lateral nerve cords are without accessory lateral nerves.     

Description and host relationships of Polymorphus spindlatus n. sp. (Acanthocephala: Polymorphidae) from the heron Nycticorax nycticorax in Peru

Polymorphus spindlatus n. sp. is described from the black-crowned night heron, Nycticorax nycticorax, in Lake Titicaca, Peru. It is distinguished from all 27 known species of the subgenus Polymorphus by its spindle-shaped proboscis and its trunk shape, the anterior 2/3 of which is ovoid, tapering into a tubular posterior end. It resembles Polymorphus brevis (=Arhythmorhynchus brevis), which is, however, longer and considerably more slender, and has smaller and more numerous proboscis hooks per row and smaller eggs. It is separated also from Polymorphus swartzi, Polymorphus striatus, Polymorphus contortus, and Polymorphus cincli by its proboscis armature (usually 18 longitudinal rows of 11-13 hooks each), among other characters. Histopathological sections of host tissue show well defined localized damage including hemorrhaging with subsequent phagocyte cell migration (granular tissue). The lumen of the host intestine is obstructed and villi show compression. The proboscis of P. spindlatus extends through the intestinal mucosa and submucosa, displacing the smooth muscle layers of the muscularis externa. Fibrosis also was observed.     

The stylet apparatus of the nemertean Paranemertes Peregrina: Its ultrastructure and role in prey capture

Summary The nemertean Paranemertes peregrina captures prey by using an eversible proboscis that is armed with a stylet apparatus. The apparatus consists of several reserve stylet sacs and a central stylet that is attached to a granular mass, called the basis. When the proboscis is everted, the central stylet is used to stab prey such as nereid polychaetes, and paralytic neurotoxins, produced in the proboscis, are inserted in the stylet-induced wounds. The central stylet averages 85 m in length and has helically-arranged grooves along its shaft. The proximal piece of the central stylet is anchored to the basis, apparently by adhesive granules in the anterior end of the basis. A basis sheath surrounds the basis and is continuous posteriorly with a duct, called the ductus ejaculatorius. Secretions in the ductus ejaculatorius may contain some of the toxin that is used to immobilize the prey. The contents of the duct are probably injected into the prey by way of the grooves on the central stylet. In the region anterior to the central stylet, there are numerous glandular cells and anchor cells that are believed to attach the stylet apparatus to the prey during attack. Each reserve stylet sac is lined by a simple epithelium. One of the epithelial cells, called the styletocyte, is greatly enlarged and fills the lumen of the sac. Several reserve stylets are assembled in a styletocyte. Each reserve stylet is formed within a membrane-bound vacuole associated with the Golgi apparatus and is composed of an inner organic core surrounded by an inorganic cortex. A duct connects each reserve stylet sac with the area around the central stylet and provides a pathway for the transfer of reserve stylets during replacement of the central stylet.     

Proboscis sensilla of the black cutworm Agrotis ypsilon (Rottemberg) (Lepidoptera: Noctuidae)

Proboscis sensilla are important for feeding biology in Lepidoptera, and are also valuable characters for species recognition and phylogenetic analysis. However, proboscis has not been satisfactorily explored in many groups in Lepidoptera so far. Here we examined the proboscis sensilla of the black cutworm Agrotis ypsilon (Rottemberg), a cosmopolitan agricultural pest of great economic significance, using scanning electron microscopy. Three types of sensilla were found on the proboscis: sensilla chaetica, sensilla basiconica, and sensilla styloconica. Sensilla chaetica occur only on the external surface of the proboscis and become shorter and more scattered toward the tip. Sensilla basiconica are arranged in longitudinal rows on the external proboscis and one longitudinal row in the inner food canal. Sensilla styloconica are the most characteristic sensilla on the proboscis, consisting of a single sensory cone inserted at the top of a stylus with six or seven longitudinal ribs, and are concentrated on the tip region, and are much longer and more numerous in females than in males. The role of proboscis sensilla in the feeding habit prediction is briefly discussed.     

Proboscis musculature in the butterfly Vanessa cardui (Nymphalidae, Lepidoptera): settling the proboscis recoiling controversy

Krenn, H. W. 2000. Proboscis musculature in the butterfly Vanessa cardui (Nymphalidae, Lepidoptera): settling the proboscis recoiling controversy. —Acta Zoologica (Stockholm) 81 : 259–266 The proboscis of Vanessa cardui (Nymphalidae) contains two basal galeal muscles and two different series of numerous oblique muscles. Both muscle series extend from the proximal region up to the tip‐region; the individual muscles of each series run a constant course throughout the proboscis. In contrast to other butterflies, the knee bend region does not have additional types of muscles. The analysis of shock‐frozen proboscises reveals that the dorsal wall is arched outwardly in the uncoiled, feeding position whereas in the coiled, resting position the dorsal proboscis wall is flat or concave. This results in a significantly greater cross‐sectional area due to the significantly greater dorso‐ventral diameter in uncoiled proboscises. After freezing the proboscis in its distal region, it can still be uncoiled, however, it cannot be fully recoiled. These morphometric and experimental results indicate that the oblique proboscis muscles are responsible for recoiling the proboscis to the resting position.     

Rhinoglena frontalis (Rotifera,Monogononta): a scanning electron microscopic study

Females and males of Rhinoglena frontalis (Monogononta, Epiphanidae) are observed by SEM and their external morphologies are compared. The two sexes differ in size and shape of the body. The female body is fusiform with a short, conical foot, while the male body is more slender and has a rather long foot. The rotatory apparatus (or corona) of both sexes is similar with only minor differences and consists of rows and tufts of cilia arranged around the mouth opening. The corona is made of two paired lobes lateral to the mouth and of a third prominent dorsal lobe, usually called proboscis. The three lobes are lined externally by dense rows of cilia, which constitute the cingulum, used for swimming. The central surface of the proboscis is covered with numerous longitudinal rows of cilia bent towards the mouth. The lateral lobes show, on their central surfaces, two concentric arcs of cirri (made of tightly packed cilia) bent towards the mouth. The similar organization of the rotatory apparatus of both sexes is related to the fact that the male, in this species, is able to feed and has a developed mastax and digestive system. The trophi of both sexes are illustrated and compared.     

A morphological study of the nervous system of the praesoma of Paulisentis fractus (Acanthocephala: Neoechinorhynchidae)

The nerve pathways in the praesoma are described for a member of the class Eoacanthocephala for the first time. Eleven nerves, five paired and one single, are traced from the cerebral ganglion to their associations with the musculature of the body wall, neck sense organs, and the musculature of the proboscis wall and the invertor muscles of the proboscis. The structure and location of the stutzzelle and series of nerve endings in the hypodermis of the body wall and at the apex of the proboscis are described.     

Acanthocephalus tahlequahensis sp. n. (Acanthocephala: Echinorhynchidae) from the the stippled darter, Etheostoma punctulatum (Agassiz), in northeastern Oklahoma.

Acanthocephalus tahlequahensis sp. n. was recovered from the intestines of 4 species of freshwater fishes, Etheostoma punctulatum, E. spectabile, Nocomis asper, and Notropis pilsbryi, collected in northeastern Oklahoma. The new species is distinguished from all other species of Acanthocephalus, except A. japonicus (Fukui and Morisita 1936) Petrochenko 1956, and A. fluviatilus Paperna 1964, by having smaller proboscis hooks. The length of the proboscis hooks for males is 27 to 38 (33) mum and for females 35 to 46 (42) mum. A. tahlequahensis is smaller than either A. japonicus or A. fluviatilis, and has about half the number of longitudinal rows of proboscis hooks of A. japonicus and half the number of proboscis hooks in each longitudinal row of A. fluviatilus. In addition to having smaller hooks. A. tahlequahensis differs from other species of Acanthocephalus parasitizing North American fishes by its smaller, spindle-shaped trunk and more hooks in each longitudinal row.     

A new species of Heterosentis Van Cleave, 1931 (Acanthocephala, Arhythmacanthidae), a parasite of pinguipedid fishes in the southwest Atlantic

A new species of arhythmacanthid acanthocephalan, Heterosentis martini n. sp., parasitic in the Argentinean sandperch Pseudopercis semifasciata (Cuvier) (Perciformes, Pinguipedidae) from the coasts of Argentina is described. Heterosentis martini n. sp. differs from all congeneric species by having 10 longitudinal rows of hooks in the proboscis, each with 7-8 hooks, consisting of 1 medium apical and 3 larger sub-apical hooks with root, and 3-4 smaller, basal, curved hooks with rudimentary roots and spines in both ventral and dorsal regions of the body. The most similar species, Heterosentis heteracanthus (Linstow, 1896) Van Cleave, 1931, and Heterosentis brasiliensis Vieira, Felizardo and Luque, 2009, also have 10 longitudinal rows of hooks, but H. heteracanthus differs from the new species by having only 3-5 (more frequently 4) hooks in each row, with only the anterior hook large and bearing a developed root. Heterosentis brasiliensis differs from the new species by possessing 2 sub-apical hooks in each row (instead of 3), similar body length but shorter proboscis, and trunk spines restricted to the ventral surface of body.     

A new genus and species of heteronemertean from the Changjiang (Yangtze) River Estuary

A new genus and species of heteronemertean, Yinia pratensis gen. nov. and sp. nov., collected from low salinity waters (salinity 0.2–0.4 ‰) at Changjiang River Estuary, is described and illustrated. The species possesses a proboscis with an outer circular and an inner longitudinal muscle layer, and is placed in family Lineidae sensu Gibson. The following combination of morphological features distinguishes the new species from any other genera in this family: proboscis with two muscle crosses; dermis without connective tissue layer between gland cells and body wall outer longitudinal muscle layer; rhynchocoel wall circular muscles not interweaving with adjacent body wall longitudinal muscles; foregut with circular somatic muscles and subepithelial gland cell layer; neurochord cells present in central nervous system; caudal cirrus missing; blood system developed into alimentary plexus extending almost the full length of the body. Another significant character is that the lobular excretory cells are extremely well developed which may represent adaptation to water of low salinity. This revised version was published online in July 2006 with corrections to the Cover Date.     

Morphology of a new deep‐sea acorn worm (class Enteropneusta,phylum Hemichordata): A part‐time demersal drifter with externalized ovaries

Ten individuals of an enteropneust in the family Torquaratoridae were videotaped between 2,900 and 3,500 m in the Eastern Pacific—one drifting a few centimeters above the bottom, two exposed on the substrate, and seven partly burrowed, reflecting a bentho‐pelagic life style. Here, we describe a captured specimen (26 cm living length) as the holotype of Allapasus aurantiacus n. gen., n. sp. The small proboscis is dome‐shaped, and the collar is only slightly wider than deep; both of these body regions are more muscular than in other torquaratorids, which presumably facilitates burrowing. The proboscis complex, in contrast to that of shallow‐living enteropneusts, lacks a pericardial sac and is located relatively posteriorly in the proboscis stalk. The stomochord is separated from the main course of the gut by the intervention of a small, plate‐like proboscis skeleton lacking posterior horns. The most anterior region of the trunk houses the pharynx, in which the pharyngeal skeletal bars are not connected by synapticles. The postpharyngeal trunk comprises three intestinal regions: prehepatic, hepatic (with conspicuous sacculations), and posthepatic. On either side of the worm, a flap of body wall (lateral wing) runs the entire length of the trunk. The two lateral wings can wrap the body so their edges meet in the dorsal midline, although they often gape open along the pharyngeal region. The holotype is a female (presumably the species is gonochoric) with numerous ovaries located in the lateral wings along the pharyngeal region. Each larger ovary contains a single primary oocyte (up to 1,500 μm in diameter) and bulges outwards in an epidermal pouch attached to the rest of the body by a slender stalk. Such externalized ovaries are unprecedented in any animal, and nothing is yet known of their role in the reproductive biology of A. aurantiacus. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.     

An enigmatic heteronemertean from the Gulf of Mexico

Heteroenopleus enigmaticus gen. nov., sp. nov. isdescribed from the northwestern Gulf of Mexico. Itoccurs both in the nearshore Gulf and in high salinityestuarine areas. Body wall musculature conforms tothe general plan of heteronemerteans, i.e. outerlongitudinal, middle circular and inner longitudinalmuscle layers. The head bears a pair of horizontallateral slits, characteristic of the lineids. Theproboscis musculature is of the heteronemerteanpalaeotype with two muscle layers, outer circularand inner longitudinal. Other morphologicalcharacters agree with those of heteronemerteans withone major exception: the proboscis is armed with tworows of structures, herein named parastylets. Thisarmature has no morphological similarity to either themicrovillar proboscideal spines of heteronemerteans orto the stylets of mono- or polystiliferans. A newsubfamily Heteroenopleinae is erected to contain theapomorphic character of an armed proboscis.