Spiral Valve Research Articles

The Anatomy of the Gastrointestinal Tract of the African Lungfish, Protopterus annectens

The gastrointestinal tract of the African lungfish Protopterus annectens is a composite, which includes the gut, the spleen, and the pancreas. The gut is formed by a short oesophagus, a longitudinal stomach, a pyloric valve, a spiraling intestine, and a cloaca. Coiling of the intestine begins dorsally below the pylorus, winding down to form six complete turns before ending into the cloaca. A reticular tissue of undisclosed nature accompanies the winding of the intestinal mucosa. The spleen is located along the right side of the stomach, overlapping the cranial end of the pancreas. The pancreas occupies the shallow area, which indicates on the gut dorsal side the beginning of the intestine coiling. In addition, up to 25 lymphatic-like nodes accompany the inner border of the spiral valve. The mesenteric artery forms a long axis for the intestine. All the components of the gastrointestinal tract are attached to each other by connective sheaths, and are wrapped by connective tissue, and by the serosa externally. We believe that several previous observations have been misinterpreted and that the anatomy of the lungfish gut is more similar among all the three lungfish genera than previously thought. Curiously, the gross anatomical organization is not modified during aestivation. We hypothesize that the absence of function is accompanied by structural modifications of the epithelium, and are currently investigating this possibility.

Anatomy and Histology of the Spiral Valve Intestine in Juvenile Australian Lungfish, Neoceratodus forsteri~!2009-02-25~!2009-04-08~!2009-06-02~!

Anatomy and Histology of the Spiral Valve Intestine in Juvenile Australian Lungfish, Neoceratodus forsteri~!2009-02-25~!2009-04-08~!2009-06-02~!

COMPACTAÇÃO DO CÓLON EM VACA. RELATO DE CASO

This work reports the clinical, laboratorial and pathological findings of colon impaction in a 3½-year-old female crossbred cow (3/4 Holstein x ¼ Gir) weighing 400kg. Clinical examination revealed apathy, tachycardia and 10% of dehydration. There was a reduction on appetite as well as ruminal and intestinal motility. Simultaneous auscultation and percussion showed a well-defined metallic area, or ping, in the 11th intercostal space. Rectal examination detected scant, pasty, blackish and fetid feces, as well as a hard, spherical structure that had adhered to the upper right abdominal cavity of the large intestine, not allowing its total palpation. Hematology diagnosed leukocytosis with neutrophilia and hyperfibrinogenemia. Increased chloride ion concentration (42,42 mEq/L) was evidenced by rumen fluid analysis. Right flank celiotomy followed by exploratory laparotomy was performed revealing colon impaction and diffuse peritonitis. Necropsy findings indicated an ovoid solid mass in the spiral valve of the ascendant colon. It was adhered to the peritoneal wall, partially covered by fibrin, and displayed focal hemorrhage areas that extended into the greater omentum. During the opening of the colonic region, mild stenosis and fecaloma obstruction were observed due to mucosal necrosis and ulceration.

Acanthobothrium minusn. sp. (Tetraphyllidea : Onchobotriidae) parasite deRaja asterias(Elasmobranchii : Rajidae) en Méditerranée

Among tetraphyllidean cestodes, parasitic in the spiral valve of Raja asterias Delaroche, colected from Algerian coasts, we obtained an onchobothriid of the genus Acanthobothrium, differing from all species of Acanthobothrium previously reported from Rajidae from Mediterranea and european Atlantic coast. This Cestode is characterized by its very small size (1-2 mm), its number of segments of the strobila (4-8), the morphology and size of hooks, the limited number (17-25) of testes and ovarian morphology. Together, these features places this Acanthobothrium in group "2" as defined by Ghoshroy & Caira (2001). We describe this onchobothriid as Acanthobothrium minus n. sp.

Chlamydoselachus africana, a new species of frilled shark from southern Africa (Chondrichthyes, Hexanchiformes, Chlamydoselachidae)

Frilled sharks (Chondrichthyes, Hexanchiformes, Chlamydoselachidae), long believed to be a monotypic family and genus, consisting of a single wide ranging species, Chlamydoselachus anguineus (Garman, 1884), is now known to contain at least two species. A new species of frilled shark, Chlamydoselachus africana, sp. nov., is described from five specimens collected from southern Africa. The new species, although difficult to distinguish externally from the well known C. anguineus, differ internally by the structural differences in the chondrocranium, lower total vertebral and spiral valve counts, and pectoral-fin radial counts. The new species, Chlamydoselachus africana, is known from off southern Angola, Namibia, and South Africa.

A Preliminary Comparison of the Vasculature of the Spiral Valve in the Yellow Stingray, Urobatis jamaicensis, and the North American Paddlefish, Polyodon spathula

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009

Anatomy and Histology of the Spiral Valve Intestine in Juvenile Australian Lungfish, Neoceratodus forsteri

The Australian lungfish, Neoceratodus forsteri, is the only vertebrate that possesses a complete spiral valve intestine with pre-pyloric coiling. This study describes the anatomy and histology of the spiral valve intestine in juvenile N. forsteri and compares it to a previous study of adult N. forsteri, thus providing a broader picture and better understanding of the intestine of the Australian lungfish. Not surprisingly, most features of the spiral valve intestine in juvenile and adult N. forsteri are similar. However, our study goes further to show that, unlike most other vertebrates, the stomach (pre-pyloris) is non-distensible (lacks rugae). Rugae are confined to the post-pyloric duodenum. The epithelium of the pyloric fold, between foregut and midgut, is ciliated and the presence of lymphoid tissue in the pyloric fold implies the involvement of this region in the immune system. Lymphoid tissue is also present around the posterior spleen in the medial axis, which indicates a broader gut-associated lymphoid tissue (GALT) in juvenile Neoceratodus than has been previously recognized in adult Neoceratodus. This study also found some node-like structures in the epithelium of the mucosal tissue, which resemble the Peyer's patches of other more advanced vertebrates. Furthermore, a previously unreported parasite was found in the spleen encased in fibrous tissue, indicating an immune response had been mounted by the host against it. These latter observations suggest that a thorough investigation of GALT in Neoceratodus is warranted.

Oncomegas Aetobatidis SP. Nov. (Cestoda: Trypanorhyncha), A Re-Description of O. Australiensis Toth, Campbell & Schmidt, 1992 and New Records of Trypanorhynch Cestodes from Australian Elasmobranch Fishes

Oncomegas aetobatidis sp. nov. (Trypanorhyncha: Eutetrarhynchidae) is described from the spiral valve of the dasyatid ray Aetobatus narinari (Euphrasen, 1790) from the Arafura Sea, Northern Territory. The new species is most closely related to O. australiensis Toth, Campbell and Schmidt, 1992 in the number of files of hooks in the metabasal region of the tentacular armature and the presence of post-ovarian testes, but differs in overall dimensions, in the size of the macro-hook in the basal armature and in the number of testes. The mature segment of O. australiensis is described for the first time. Cestodes reported for the first time from Australian waters are: Pterobothrium platycephalum (Shipley & Hornell, 1906) Dollfus, 1930 (Pterobothriidae) from Himantura jenkinsii (Annandale, 1909) and Himantura spParachristianella indonesiensis Palm, 2004 (Eutetrarhynchidae) from Pastinachus sephen (Forsskål, 1775), Himantura undulata (Bleeker, 1852), H. jenkinsii and H. toshi Whitley, 1939, Prochristianella macracantha Palm, 2004 (Eutetrarhynchidae) from Pastinachus sephen (Forsskål, 1775) and Mecistobothrium johnstonei (Southwell, 1929) Beveridge and Campbell, 1998 (Eutetrarhynchidae) from P. sephen. New host records are: Pterobothrium australiense Campbell and Beveridge, 1996 (Pterobothriidae) from Anoxypristis cuspidata (Latham, 1794); Parachristianella baverstocki Beveridge, 1990 (Eutetrarhynchidae) from P. sephen, H. jenkinsii, H. toshi and H. undulata; Parachristianella monomegacantha Kruse, 1959 (Eutetrarhynchidae) from Himantura draco Compagno and Heemstra, 1984 and Rhynchobatus australis Whitley, 1939; Dollfusiella michiae (Southwell, 1929) Beveridge, Neifar and Euzet, 2004 (Eutetrarhynchidae) from Rhina ancylostoma Bloch and Schneider, 1801; and Dollfusiella ocallaghani (Beveridge, 1990) Beveridge and Jones, 2000 (Eutetrarhynchidae) from R. australis and H. jenkinsii.

The Florida amphioxus (Cephalochordata) hosts larvae of the tapeworm Acanthobothrium brevissime: natural history, anatomy and taxonomic identification of the parasite

AbstractPlerocercoid larvae of a tapeworm are frequently found in the hindgut lumen of the Florida amphioxus (Branchiostoma floridae) in central west Florida. About three‐quarters of the adult amphioxus are parasitized. On average, each adult amphioxus hosts about five tapeworm larvae. The residence time of the parasites in the amphioxus gut appears to be in the order of several months, which is considerably shorter than the potential lifetime of the host. The living larvae range in length (when fully extended) from 300 to 850 µm and are approximately cone‐shaped, tapering to a point posteriorly and bearing a single large sucker anteriorly. Toward the anterior end of the body are four hookless bothridia, each indented by three loculi plus an inconspicuous accessory sucker. The larvae initiate the early stages of hook formation when they are cultured for a few days in urea‐saline (mimicking the gut fluid of the definitive host, which is an elasmobranch). The tapeworm larvae are identifiable to genus and species on the basis of correspondences between their nuclear ribosomal DNA genes and those of adult specimens of Acanthobothrium brevissime recovered from the spiral valve of a stingray from the same environment.

Osmoregulation in juvenile Chinese sturgeon (Acipenser sinensis Gray) during brackish water adaptation

The osmoregulation capabilities of 7-month-old juvenile Chinese sturgeon (Acipenser sinensis Gray) (128.8 +/- 15 g) transferred directly from fresh water (0 per thousand, 46 mOsmol kg(-1)) to brackish water (10 per thousand, 273 mOsmol kg(-1)) were studied over a 20-day period. Changes in serum osmolarity, chloride (Cl(-)), sodium (Na+), potassium (K+) and calcium (Ca2+) ion concentrations, as well as gill and spiral valve Na+,K+-ATPase activities were measured at 3, 12, 24, 72, 216 and 480 h after transfer to BW. The serum osmolarity and ion concentrations (Na+, Cl(-) and Ca2+) increased immediately after the transference to BW, reaching maximum at 24 h and returned to a new steady state at 216 h, while the FW control group maintained basal levels which showed lower (P < 0.05) than the BW group. Gill Na+,K+-ATPase activity of BW group exhibited an abrupt decrease in the first 3 h after transfer, but began to increase at 3 h, reaching a peak value at 24 h, and returned to a new steady state at 216 h. The differences between gill Na+,K+-ATPase activity of BW and FW fish were significant (P < 0.05) after 12 h. In contrast, Na+,K+-ATPase activity of the spiral valve showed transient increase after transference from FW to BW, and then decreased rapidly at 3 h, reaching the lowest at 24 h after transference. At 216 h after exposure to BW, Na+,K+-ATPase activities of the spiral valve increased slowly to the levels of FW control. The results of our study indicate the existence of hyposmoregulatory adaptive mechanisms in 7-month-old juvenile Chinese sturgeon which enable this fish to acclimate itself successfully to brackish water.

Redescriptions of four species of Otobothrium Linton, 1890 (Cestoda: Trypanorhyncha), including new records from Australia, New Caledonia and Malaysia, with the description of O. parvum n. sp.

Redescriptions are provided of Otobothrium carcharidis (Shipley &amp; Hornell, 1906), O. crenacolle Linton, 1890, O. curtum (Linton, 1909) and O. propecysticum Dollfus, 1969 based on the type specimens and new material collected from elasmobranch hosts from Australia, Malaysia and New Caledonia. All are considered to be valid species. A neotype has been designated for O. crenacolle. A new species, O. parvum, is described from the spiral valve of Carcharhinus amblyrhynchos (Bleeker, 1856) and Triaenodon obesus (Rüppell, 1837) from New Caledonia. Otobothrium minutum Subhapradha, 1955 is considered to be a valid but poorly described species, being differentiated on the basis of a lack of testes posterior to the ovary. Otobothrium cysticum (Meyer, 1842) is considered a species inquirenda. The presence of an hermaphroditic sac is a new character for the genus while O. curtum lacks bothrial pits, a characteristic found in all congeners examined. The species described or redescribed here can be distinguished based on the number of segments and the number and distribution of testes, in addition to the features of the scolex. Otobothrium crenacolle is readily distinguished by its larger bothrial pits. The metabasal armature begins on either the bothrial or internal surface of the tentacle depending upon the species.

A New Species and New Records of Parachristianella Dollfus, 1946 (Cestoda: Trypanorhyncha) from the Gulf of California, Mexico

Parachristianella parva sp. nov. is described from the spiral valve of Urobatis maculatus Garman, 1913 from the Gulf of California, Mexico. The new species is distinguished by its small size and small number of testes per segment (8–10). Parachristianella trygonis Dollfus, 1946 is reported from the spiral valve of Mobula munkiana Notarbartolo di Sciari, 1987 and from Dasyatis brevis (Garman, 1880), whereas the adult of Parachristianella dimegacantha Kruse, 1959 is described for the first time from the spiral valves of Urotrygon simulatrix Miyake and McEachran, 1988; Sphyrna zygaena (Linnaeus, 1758); and Dasyatis longus (Garman, 1880), all from the Gulf of California.

Comparison of acid mucin goblet cell distribution and Hox13 expression patterns in the developing vertebrate digestive tract

The digestive tract of vertebrates is a complex organ system required for the digestion of food and the absorption of nutrients. The colon evolved as a water absorption organ essential for vertebrates to survive on land. In contrast to land vertebrates, the Chondrichthyes (sharks, skates and rays) are nearly iso-osmotic with their ocean environment and do not reabsorb water from food waste. To understand the origin of the vertebrate colon, we examined the distribution of sulfated and sialyated mucus-producing cells in the little skate, Raja erinacea, as an indication of water absorption function in the chondrichthian digestive tract. The percentage of acid mucin producing goblet cells was analyzed in the spiral valve and hindgut of little skate and the small intestine and colon of mouse embryos. Levels of acid mucins in the hindgut of the little skate was comparable to that of the small intestines of terrestrial vertebrates, whereas the distal region of the spiral valve contained high levels of acid mucin producing cells similar to the colon of mouse and chick. The low numbers of acid mucins in the little skate hindgut confirms that a functional colon for water absorption is absent in the Chondrichthyes. Interestingly, the presence of high levels of acid mucins in the posterior spiral valve provides evidence for a possible primordial water-absorbing organ in the elasmobranchs. Hoxd13 patterns acid mucins in the colons of terrestrial vertebrates. Expression of Hoxd13 and Hoxa13 in R. erinacea suggests conserved roles for Hox genes in patterning the early hindgut.

Osmoregulation, ionoregulation and acid–base regulation by the gastrointestinal tract after feeding in the elasmobranch (Squalus acanthias)

In order to study the physiological consequences of voluntary feeding in the gastrointestinal tract of a ureotelic marine elasmobranch, dogfish (fasted for 96 h) were sampled at various times up to 360 h after consuming a 5-6% ration of teleost fish (hake) under natural feeding conditions. Digestion and absorption were completed between 120 and 360 h post-feeding. The tissue masses of different segments of the gastrointestinal tract increased and decreased markedly as the chyme moved through, mainly because of fluid engorgement rather than hyperplasia. In fasted dogfish, the cardiac and pyloric stomachs contained only small volumes of highly acidic fluid (pH 1.77+/-1.12, 2.05+/-0.08) similar in composition to seawater. Feeding resulted in gastric pHs of 3.20+/-0.31 and 3.95+/-0.40 at 6 h, followed by slow declines through 60 h. An alkaline tide in the blood also occurred at 6 h. In the face of large changing masses of highly acidic chyme in the stomachs, the pH (6.50+/-0.10), ionic composition and volume of chyme in the intestine (spiral valve) were precisely regulated from 6 to 60 h post-feeding at very different values from those in the stomachs, and intestinal HCO3(-) remained low (5.12+/-0.83 mmol l(-1)). The colon was usually empty and its pH constant at 7.20+/-0.16 at all times. Despite the ingestion of strongly hypo-osmotic teleost tissue, the osmolality of the chyme remained in equilibrium with that of the blood plasma in all segments at all times after feeding. Much of the osmotic equilibration was because of the secretion of urea into the chyme, particularly in the intestine. After feeding, gastric fluid concentrations of Na(+) and Mg(2+) declined, K(+) and Ca(2+) increased, whereas Cl(-) exhibited little change, indicating that additional drinking of seawater was minimal. Na(+), K(+), water and especially Cl(-) were absorbed in the intestine, whereas Mg(2+) and Ca(2+) were largely excluded. Our results illustrate the complex integration of digestive and ionoregulatory function in the elasmobranch digestive tract, and marked differences from the teleost pattern.

Pseudolacistorhynchusnanus N. SP. (Cestoda: Trypanorhyncha) Parasitic Inthespiralvalve Ofthezebra Shark,Stegostoma Fasciatum(Hermann, 1783)

SummaryPseudolacistorhynchus nanus sp. nov. (Cestoda: Trypanorhyncha) is described from the spiral valve of the zebra shark, Stegostoma fasciatum (Hermann, 1783) from New Caledonia, Malaysia and northern Australia. The presence of paired bothria, a metabasal tentacular armature with a single row of intercalary hooks and the presence of a distinctive basal armature with bill-hooks place the species in the genus Pseudolacistorhynchus Palm, 1995. It is readily differentiated from congeners by its small size, in having six rather than five hooks in each principal row and four hooks in each intercalary row.

Three new genera and seven new species of trypanorhynch cestodes (family Eutetrarhynchidae) from manta rays, Mobula spp. (Mobulidae) from the Gulf of California, Mexico

Three new genera of eutetrarhynchid trypanorhynch cestodes are described from Mobula spp. (Mobulidae) from the Gulf of California, Mexico. Fellicocestus mobulae gen. et sp. n. from the gall bladder of Mobula japonica (Miller et Henle) is distinguished by elongate bothria, a pars bothrialis equal in length to the pars vaginalis, masses of gland cells in the pars vaginalis and an heteromorphous armature in which hook rows arise from a central file of hooks on the bothrial surface of the tentacle and terminate in a central file on the antibothrial surface. Species of Mobulocestus gen. n. occur in the nephridial system and cloaca of rays and are characterized by two bothria, an heteroacanthous armature with hook rows beginning on the bothrial surface and terminating on the antibothrial surface, and by hooks at the beginnings of rows with an apical cavity. M. nephritidis sp. n. and M. lepidoscolex sp. n., both from the nephridial system of Mobula thurstoni (Lloyd) are differentiated by testis number and by the presence of scale-like microtriches on the tegument of the scolex of M. lepidoscolex. M. mollis sp. n., from the cloaca of Mobula thurstoni is distinguished by testis number (97-111 in M. lepidoscolex, 20-22 in M. nephriticus and 48-70 in M. mollis). Hemionchos gen. n. from the spiral valve of Mobula spp. has two bothria, an heteroacanthous armature, hook rows arising on the bothrial surface and terminating on the antibothrial surface and hooks at the beginning of rows with an apical cavity. It differs from Mobulocestus in having a distinctive basal armature and both hook files 1 and 1' on the bothrial surface, but has an additional, small, satellite hook adjacent to each hook 1'. H. striatus sp. n. from the spiral valve of Mobula thurstoni and M. japonica is differentiated by having a basal armature of closely packed arrays of small, uncinate hooks. H. mobulae sp. n. from the spiral valve of Mobula japonica and M. munkiana Notarbartolo di Sciari, differs in testis number and in having large, flattened hooks in the basal armature. H. maior sp. n., from the spiral valve of M. japonica, is larger, differing in both the number of testes and in the basal armature.

Two new species ofPseudochristianellaCampbell &amp; Beveridge, 1990 (Cestoda: Trypanorhyncha) from elasmobranch fishes from the Gulf of California, Mexico

Pseudochristionella elegantissima sp. nov. (Cestoda: Trypanorhyncha) is described from the spiral valves of the rays Dasyatis brevis (Garman, 1880) and D. longus (Garman, 1880), from the Gulf of California, Mexico. Also described is P. nudisculo sp. nov. from rays Rhinobatos productus Ayres, 1854, D. longus, Myliobatis longirostris Applegate & Fitch, 1964 and Zapteryx exasperat (Jordan & Gilbert, 1880) from the same location. The species are distinguished from one another and from the only existing species within the genus, P. southwelli Campbel & Beveridge, 1990, by differences in the arrangement of bill-hooks on the external surface of the basal swelling of the tentacle and by the number of hooks in each row of the metabasasl armature.

A NEW SPECIES OF ONCHOBOTHRIIDAE (TETRAPHYLLIDEA) FROM CHILOSCYLLIUM PLAGIOSUM (ELASMOBRANCHII: ORECTOLOBIDAE) IN CHINA

A new species of cestode, Yorkeria xiamenensis n. sp., is described from the spiral valve of Chiloscyllium plagiosum from coastal waters of Xiamen, China. It is the first record of Yorkeria in China. The new species is distinguished from all other species of Yorkeria by its possession of the following characters: the length of specimens, 15.8 mm; 63-95 proglottids; 71-85 testes per proglottid; large medial and lateral hooks in scolex; and eggs with 2 long polar filaments. The new species most closely resembles Y. parva Southwell, 1927 in the follicular vitellaria and similar ratio of lateral-to-medial hooks (1:2.15 vs. 1:2-2.5). However, Y. xiamenensis n. sp. has a longer strobila, more proglottids, a smaller ratio of pedicel to cephalic peduncle, larger hooks, more testes, and a different host.

Torpedo formosa sp. nov., a new species of electric ray (Chondrichthyes: Torpediniformes: Torpedinidae) from Taiwan

A new species of torpedo ray, Torpedo formosa, sp. nov., is described from specimens collected from northeastern Taiwan. The new species is placed in the subgenus Tetronarce based on a uniform purplish dorsal coloration and the absence of papillae around the spiracles. It is distinct from the sympatric T. tokionis, the only other known Torpedo (Tetronarce) species from the western North Pacific, by a disc that is wider than long, a shorter tail, a greater number of spiral valve turns, and its dorsal coloration. It has been misidentified as T. nobiliana, but is distinguished from it by having longer snout and spiracle lengths, a lower vertebral count, and a caudal fin height that is greater than the distance from the first dorsal origin to the caudal fin origin. This new species, at present, is known only from the northeast coast of Taiwan between Keelung and Suao primarily at depths of less than 300m.

Gilquiniid cestodes (Trypanorhyncha) from elasmobranch fishes off New Caledonia with descriptions of two new genera and a new species

Cestodes were collected from deep-sea sharks caught off New Caledonia, South Pacific. Vittirhynchus squali n. g., n. sp. (Trypanorhyncha: Gilquiniidae) is described from the spiral valve of Squalus melanurus Fourmanoir & Rivaton. The new genus possesses four bothria and a typical heteroacanthous metabasal armature but has a file of three macrohooks forming a short chainette on the internal surface of the basal armature. Sagittirhynchus aculeatus n. g., n. sp., from the spiral valve of Centrophorus sp. (undescribed), also has four bothria and a typical heteroacanthous armature but lacks a distinctive basal swelling and has the final hooks of each principal row prominently enlarged. Gilquinia minor n. sp., from the spiral valve of Centrophorus sp. (undescribed), is distinguished by the presence of only five hooks per principal row compared with eight in congeners. Gilquinia sp. is reported from Squalus melanurus. G. robertsoni Beveridge, 1990 is reported from S. megalops (Macleay).