Theileria electrophorin.sp., a parasite of the electric eel Electrophorus electricus (Osteichthyes: Cypriniformes: Gymnotidae) from Amazonian Brazil

The name Theileria electrophori n.sp. is proposed for a small parasite described in the erythrocytes of the electric eel, Electrophorus electricus, from Amazonian Brazil. Division of the organism in the erythrocyte produces only four bacilliform daughter cells which become scattered in the host cell, without a cruciform or rosette-shaped disposition. Exoerythrocytic meronts producing a large number of merozoites were encountered in Giemsa-stained impression smears of the internal organs, principally in the liver, and are presumably the source of the intraerythrocytic forms of the parasite. This developmental pattern is characteristic of piroplasms within the family Theileriidae, where the author considers the parasite of E. electricus to most appropriately belong. It effectively distinguishes the organism from the dactylosomatid parasites Babesiosoma Jakowska and Nigrelli, 1956 and Dactylosoma Labbé, 1894 also found in fishes. This appears to be the second report of Theileria Bettencourt, Franca and Borges, 1907 in a fish.     

Comparative histochemical studies of iron absorption in three fresh water teleosts.

Absorption of iron in the intestine of three different species of fishes, namely; Claris batrachus, Channa striatus and Esomus danricus has been described. These three species of fishes have different feeding habits, being omnivorus, carnivorus and herbivorus respectively. The absorption of iron has been studied at different time intervals; after three hours, six hours and nine hours. The mucosal epithelial cells, submucosal blood vessels and blood capilaries were the main site of iron absorption. A comparative account of absorption of iron of all three fishes is described and discussed.     

Trypanosoma pacifica sp. n. from the English Sole Parophrys vetulus Girard from Oregon*

Trypanosoma pacifica sp. n. is described from the blood of the English sole, Parophrys vetulus Girard, from Oregon. The total length averages 35.9 μm of which 15.4 μm is free flagellum. Comparisons are made with other trypanosomes reported from related species of fishes and with those reported from marine fishes adjacent to North America.     

Parasites of fishes in the recently inundated ephemeral Lake Liambezi,Namibia

Lake Liambezi forms the periodic connection between the upper Zambezi, Kwando and Okavango rivers. A full parasitological assessment was conducted on 86 fish, representing 14 species in six families sampled in August 2011. Parasite diversity was low and dominated by species with complex life cycles involving intermediate hosts. Most prevalent were larval nematodes (Contracaecum sp.) infecting 12 and Trypanasoma sp. infecting nine of the 14 host species. The intra-erythrocytic parasite Babesiosoma mariae was found in the blood of Coptodon rendalli and Oreochromis andersonii with prevalence of 50% and 60%, respectively. The host-specific monogenean Annulotrema hepseti was recorded only from H. cuvieri with a prevalence of 100%. Notable absences were the copepod and branchiuran parasites that have direct lifecycles and usually occur in high prevalence and abundance in the region. Because parasites with direct life cycles can only be transported into the lake on the host fish, their absence suggests limited immigration of infected fishes into the lake. This suggests that internal recruitment dominates over immigration in the fish population dynamics in Lake Liambezi.     

Trypanosoma occidentalis sp. n. from Freshwater Teleosts in Washington State*,†

SYNOPSIS. Trypanosoma occidentalis sp. n., a hemoflagellate encountered in the blood plasma of 3 freshwater teleosts, Cottus gulosus, C. rhotheus (Family Cottidae) and Gasterosteus aculeatus (Family Gasterosteidae) from Washington State, is described and recorded. Morphologic and morphometric features are detailed, and comparisons are made with other trypanosomes reported from North American fishes and from related species of teleosts from Eurasia. The relationship of the geographic isolation of parasite, hosts, and potential vector in the determination of the new species is discussed.     

Haematozoa of fishes in Humboldt Bay, California.

Five hundred seven fish representing 45 species from Humboldt Bay, California (USA) were examined for blood parasites. Four fish (less than 1%) from two species were infected. Haemogregarina leptocotti sp. n. is described from one of 33 staghorn sculpin (Leptocottus armatus). Haemogregarina roelofsi sp. n. is described from three of 15 black rockfish (Sebastes melanops). Gametocytes of H. leptocotti sp. n. averaged 6.1 x 2.1 microns with a 2.7 x 1.7 microns oval nucleus; those of H. roelofsi sp. n. averaged 5.5 x 2.7 microns with a 2.5 x 2.2 microns rectangular nucleus. Neither species of parasite had distinct chromatin granules, a polar cap, or more than one gametocyte in an infected cell. Haematozoa are relatively rare in fishes of the northeastern Pacific Ocean.     

Morphology of the gills of larval and parasitic adult sea lamprey,Petromyzon marinus L.

The general morphology of the gills is similar in larval (ammocoetes) and parasitic adult sea lampreys, Petromyzon marinus, despite different methods of ventilation necessitated by their feeding habits. The gill lamellae are supported by randomly-distributed pillar cells which enclose blood spaces and collagen columns. The distribution of these cells in lampreys is different from that of higher fishes and it may be inefficient for respiratory exchange. The presence of cytoplasmic microfilaments suggests that these cells have the ability to reduce the lamellar blood spaces through contraction. Marginal channels at the tips of the lamellae are lined only by endothelial cells. The thickness of the water-blood pathway in lampreys falls within the range described for higher fishes, with the most efficient gas exchange likely occurring at the lamellar tips where only a single layer of epithelial cells is present. The abrupt increase in height of the epithelium near the lamellar bases in adults, compared to the gradual transition in height along the lamellae in ammocoetes, is perhaps reflective of higher oxygen requirements during the parasitic stage. The consistent appearance of wide, lateral intercellular spaces within the respiratory epithelium of lampreys indicates possible involvement of these spaces in transport. Mucous secretion appears to be an important function of the superficial platelet cells in ammocoetes. “Mitochondria-rich” and “mitochondria-poor” superficial cells are observed in both ammocoetes and adults, with the mitochondria-rich cells more prevalent toward the lamellar bases. The possibility that at least some of these cells may be involved in absorption is discussed. Mitochondria-rich cells in the interlamellar region are morphologically different in ammocoetes and adults but all possess an abundance of smooth endoplasmic reticulum and hence resemble “chloride cells” of higher fishes. The similarity of these cells in the parasitic adult lamprey to chloride cells of marine fishes may reflect the potential of the adult lamprey to osmoregulate in salt water. A scarcity of these cells in ammocoetes and their resemblance to chloride cells in freshwater fishes may reflect the restriction of larval lampreys to a freshwater habitat.     

四种鱼类外周血红细胞细胞周期及DNA含量

通过流式细胞仪测量了兴国红鲤（Ｃｙｐｒｉｎｕｓ ｃａｒｐｉｏ Ｖａｒ． Ｓｉｎｇｕｏｎｅｎｓｉｓ）、奥利亚罗非鱼（Ｓａｒｏｔｈｅｒｏｄｏｎ ａｕｒｅａ）、 鳙（Ａｒｉｓｔｉｃｈｔｈｙｓ ｎｏｂｉｌｉｓ Ｒ．）和团头鲂（Ｍｅｇａｌｏｂｒａｍａ ａｍｂｌｙｃｅｐｈａｌａ Ｙｉｎ．）红细胞的ＤＮＡ含量,四种鱼与鸡红细胞ＤＮＡ含量的比值分别为１·６５、０．９６、０．９１、１·１５,以鸡红细胞ＤＮＡ含量２．３ｐｇ／Ｎ计算,四种鱼二倍体体细胞的 ＤＮＡ含量分别为３．８０ ｐｇ／Ｎ, ２． ２２ｐｇ／Ｎ、２． ０８ｐｇ／Ｎ、 ２． ６６ｐｇ／Ｎ。另外,四种鱼外周血红细胞分别有２６％、 ２６％、 ２３％、 ２４％的细胞处于 ＤＮＡ合成期（Ｓ）,ＤＮＡ合成后期（Ｇ２）和分裂期（Ｍ）,这表明这四种鱼类的外周血红细胞并非失去分裂能力的特化细胞群,它们表现了较强的细胞周期现象。这有可能是这几种硬骨鱼类外周血仍具有造血功能的缘故。     

Development of Babesiosoma stableri (Dactylosomatidae; Adeleida; Apicomplexa) in its Leech Vector (Batracobdella picta) and the Relationship of the Dactylosomatids to the Piroplasms of Higher Vertebrates

The sporogonic and merogonic development of Babesiosoma stableri Schmittner & McGhee, 1961 within its definitive host and vector, a leech Batracobdella picta (Verrill, 1872), was studied by light and electron microscopy. Gamonts released from frog erythrocytes in the blood meal of the leech associated in syzygy and fused; the gamonts were isogamous and only 1 microgamete was formed. The ultrastructural appearance of the resulting zygote was similar to that of the gamonts, but it was larger. The zygote had an apical complex (including a polar ring, conoid and 2 pre-conoidal rings and micronemes, but no recognizable rhoptries), triple-membraned pellicle, about 40 subpellicular microtubules and prominent stores of amylopectin. Zygotes penetrated the cells of the intestine and underwent sporogony directly within the cytosplasm of the ieech epithelial cell without the formation of a parasitophorous vacuole. Eight sporozoites budded simultaneously around the periphery of an irregularly shaped oocyst. No oocyst wall was formed. Each sporozoite had a complete apical complex (including rhoptries), abundant amylopectin inclusions and a triple-membraned pellicle with about 32 subpellicular microtubules. The sporozoites initiated merogonic replication primarily within the salivary cells of the leech although other tissues, such as muscle, were infected. Each meront produced 4 merozoites by simultaneous budding, forming a cruciform meront typical of the intraerythrocytic development of this parasite. The meront was located directly within the cytoplasm of the host cell. Merozoites, with abundant amylopectin, had a complete apical complex and triple-membraned pellicle with about 40 subpellicular microtubules. The merozoites either initiated a further cycle of replication, or they moved into the ductules of the leech salivary cells which extend to the tip of the proboscis. Observations on gametogenesis. syngamy and sporogony of B. stableri in its leech host indicate that the family Dactylosomatidae should be placed in the suborder Adeleina (Eucoccidiida: Apicomplexa). Babesiosoma stableri was transmitted to uninfected frogs (Rana spp.) by the bite of infected leeches. Prepatent periods ranged from 26 to 38 days at 25° C. Despite a directed search in laboratory reared tadpoles which had each been injected intraperitoneally with 150,000 merozoites, no pre-erythrocytic developmental stages were observed. Similarities in their biology suggest close phylogenetic affinities of the dactylosomatids, and other adeleid blood parasites, with the piroplasms of higher vertebrates.     

Allopodocotyle chiliticorum n. sp. (Digenea: Opecoelidae) from redlip shiners, Notropis chiliticus, in Basin Creek, North Carolina

Allopodocotyle chiliticorum n. sp. is described from the intestines of redlip shiners (Notropis chiliticus) from Basin Creek, North Carolina. The new species is characterized by circumcecal vitelline fields that are not confluent in the post-testicular space, which distinguishes it from the 3 previously known species of this genus described from freshwater fishes. The new species is characterized further by an elongate vitelline reservoir lying dorsal to the ovary, an ovary as large or larger than the testes, and an excretory vesicle not reaching the posterior testis. A. chiliticorum n. sp. most closely resembles Allopodocotyle lepomis (Dobrovolny, 1939) in body shape, testes shape, and terminal genitalia but is distinguished further from this species by the extent of the intestinal ceca. The new species is the fourth species of Allopodocotyle known from freshwater fishes in North America.     

Chloromyxum schurovi sp.n.--new myxosporidian species (Myxosporea: Sphaerosporidae) from salmonid fishes (Salmonidae)

New species of the myxosporidian genus Chloromyxum is described from salmonid fishes collected in Karelia, Norway and Finland in 1992-1998.     

Isolation of enterotoxigenic Aeromonas from fish.

This paper reports two different enterotoxigenic classes of the genus Aeromonas isolated from fishes. Strains of A. sobria were isolated from healthy fishes only wheras strains of A. hydrophila were isolated from both healthy and moribund fishes. Aeromonas sobria and hydrophilia strains produced a cytotoxic factor and were highly proteolytic. Seventy-five percent (75%) of the A. sobria strains produced only one type of hemolysis on 5% blood agar, but 92% of the A. hydrophilia produced two types of hemolysis. Enterotoxigenicity of all strains was tested by the rabbit gut loop technique and the suckling mouse test. Most of those Aeromonads were enterotoxigenic. Enterotoxigenic strains appeared to produce two different enterotoxins which were antigenically related, but they seemed to have different mechanisms of action. Enterotoxins of Aeromonas were shown to be antigenically different from those of E. coli.     

Metadena phoceae n. sp. (Digenea: Cryptogonimidae), a rectal parasite of the shore rockling Gaidropsarus mediterraneus (Teleostei: Lotidae) in the western Mediterranean

Metadena phoceae n. sp. is described and figured in detail from the rectum of the shore rockling Gaidropsarus mediterraneus (Lotidae) in the Gulf of Marseilles and off Corsica. It is compared with other cryptogonimids occurring in Mediterranean and Black Sea fishes and is distinguished from its closest relatives, M. depressa (Stossich, 1883) and M. pauli (Vlassenko, 1931), which occur in sparid and sciaenid fishes, respectively, by both morphometrical and biological features. The host-specificity of cryptogonimids occurring in Mediterranean and Black Sea fishes is commented upon.     

Gobioid fauna of Veller estuary,Portonovo, S. India

Summary The distribution and the habits of Gobioid fishes in the Vellar Estuary were described.     

Syncoelicotyloides macruri gen. et sp. n.--the first representative of the subfamily Syncoelidotylinae (Microcotylidae, Monogenea) from macruriform fishes

Syncoelicotyloides macruri gen. et sp. nov., a monogenean of the subfamily Syncoelicotylinae Mamaev et Subtschenko, 1978, is described. Members of this subfamily were known only from Notacanthiformes and are found for the first time in Macrouriformes. This fact is considered by the authors as a confirmation of the earlier supposition (Mamaev, Zubtschenko, 1978) about phylogenetic closeness of these fishes.     

Hysterothylacium patagonense n. sp. (Nematoda: Anisakidae) from freshwater fishes in Patagonia,Argentina, with a key to the species of Hysterothylacium in American freshwater fishes

A new anisakid nematode, Hysterothylacium patagonense n. sp., is described from the intestine of the temperate bass Percichthys trucha (Cuvier & Valenciennes), a freshwater fish from Lake Aluminé, Patagonia, Argentina. It is characterised mainly by the absence of lateral alae, the length ratio of the caecum and ventricular appendix (1:0.9–1.8), the length of the spicules (0.952–1.292 mm) and the presence of minute spines on the tip of the tail. In the same locality and in Lake Huechulafquen, advanced third-stage and fourth-stage larvae of this parasite were also recorded from the digestive tract of the introduced salmonids, Salvelinus fontinalis (Mitchell), Oncorhynchus mykiss (Walbaum) and Salmo trutta L. This is the second Hysterothylacium species described from freshwater fishes in South America. A key to Hysterothylacium species parasitising American freshwater fishes is provided.     

Diclidophora embiotocae sp. n. (Monogenea, Diclidophoridae), a parasite of embiotocid fishes of Oregon.

Diclidophora embiotocae sp. n. is described from adult specimens obtained from the gills of three species of embiotocid fishes from the central coast of Oregon. It differs from all other members of the genus in hosts, geographic location, and in possessing pre- and para-ovarian, as well as post-ovarian testes. Diagnosis of Diclidophora (Yamaguti 1963) is emended.     

Vascular endothelium (review). I. General morphology. 2B: phylogenesis of the vascular endothelium

The phylogenetic descent of vascular endothelium from mesenchyme--derived precursors is described related to the development of a vessel--bound microcirculation. Endothelial precursors in primitive animals may have migrated into tissue clefts gradually forming vascular tubes. True microcirculatory vessels at first appear in the nemertines, a closed vascular system is present in some annelids whereas in arthropods an open lacunar system predominates. The first appearance of true endotheliocytes is under discussion; the author gives some evidence that it is present already in some annelids. Precursor of the endothelial wall of vessels may be the so called "Leydig's membrane", covered with amoebocytes and other mesenchymal cells. The molluscs exhibit many variants of endothelium. In the fishes, the vascular system begins to split into a blood and a lymphatic system. Obviously the specialization of endothelium correlates with the level of evolution. Despite the complicated course, the evolution of endothelium may be regarded as monophyletic.     

The Copulatory Organ of Pantodon buchholzi Peters (Teleostei)

The copulatory organ of Pantodon buchholzi is described. It consists of two folded, complex structures, situated in two pouches, which open ventrally. The wall between the pouches contains the modified skeletal elements of a part of the anal fin. Laterally each pouch is covered by a bony plate. The structures are connected ventrally to the bony plates and consist of a spiral of parallel bone rays, connective tissue with many blood vessels, and covering epithelium. The organ is different from all other copulatory organs described in fishes.     

Antifreeze glycoprotein levels in Antarctic notothenioid fishes inhabiting different thermal environments and the effect of warm acclimation

A quantification method was developed to determine the concentrations of the major antifreeze glycoprotein (AFGP) isoforms in the blood of Antarctic notothenioid fishes. Serum samples were precipitated with 2.5% TCA and the supernatant containing AFGPs were chromatographed on an HPLC size exclusion column and the concentrations of the major AFGP size classes were determined from the areas of the corresponding peaks in the elution profile. Eight species of Antarctic notothenioid fishes were examined and their blood AFGP concentrations varied from 5 to 35 mg/mL. All of these fishes synthesized both the large and small AFGPs, but maintained higher levels of small AFGPs than the large ones in their blood. The species inhabiting more severe water environments (lower temperature and presence of ice) had higher serum AFGP levels than those in milder environments. The cryopelagic Pagothenia borchgrevinki decreased their blood AFGP concentrations in response to warm acclimation, but to a much lower extent in comparison to the antifreeze-bearing fishes in the Northern Hemisphere. After being warm acclimated at +4 degrees C for 16 weeks, the serum concentrations of the small and large AFGPs were decreased by about 60% and 20%, respectively.