Paraophioidina scolecoides n. sp., a New Aseptate Gregarine from Cultured Pacific White Shrimp Penaeus vannamei

The aseptate gregarine Paraophloidina scolecoides n. sp. (Eugregarinorida: Lecudinidae) heavily infected the midgut of cultured larval and postlarval specimens of Penaeus vannamei from a commercial 'seed-production' facility in Texas, USA. It is morphologically similar to P. korotneffi and P. vibiliae, but it can be distinguished from them and from other members of the genus by having gamonts associated exclusively by lateral syzygy. Shrimp acquired the infection at the facility; nauplii did not show any evidence of infection, but protozoea, mysis, and postlarval shrimp had a prevalence and intensity of infection ranging from 56 to 80 % and 10 to >50 parasites, respectively. Infected shrimp removed from the facility to aquaria at another location lost their gamont infection within 7 days When voided from the gut, the gregarine disintegrated in seawater. Results suggest that P. vannamei is an accidental host, although a survey of representative members of the invertebrate fauna from the environment associated with the facility failed to discover other hosts. No link was established between infection and either the broodstock or the water or detritus from the nursery or broodstock tanks.

Experimental Infection of Contracaecum tipapillatum (Nematoda: Anisakinae) from Mexico in the Domestic Cat

Juveniles of Contracaecum multipapillatum infected the Mayan cichlid (Cichlasoma urophthalmus) and adults infected the olivaceous cormorant (Phalacrocorax olivaceus) and the great egret (Casmerodius albus) in the coastal lagoon at Celestun, State of Yucatan, Mexico. All are new host records, and, even though the geographic locality record of Mexico for the species has not been published, unidentified but presumably conspecific specimens have been reported from there. When juveniles of C. multipapillatum were fed to a kitten, but not rats, ducks, or chickens, they developed into adults. Measurements and morphological data are provided on the specimens from the kitten. Development of an avian ascaridoid in the intestine of a mammal increases the potential of this widespread species to infect other mammals, including humans.

Caridean Shrimps Associated with the Slimy Sea Plume (Pseudopterogorigia americana) in Midsummer at Guana Island, British Virgin Islands, West Indies

Fifty-one slimy sea plumes (Pseudopterogorgia americana Gmelin, 1791) were sampled for caridean shrimps at Guana Island, British Virgin Islands, during one week in July 1992. Sam- pling depth ranged from 3-22 m. Nine species were collected: Hippolyte nicholsoni Chace, 1972; Latreutes sp.; Neopontonides chacei Heard, 1986; Perclimenes cf. patae Heard and Spotte, 1991; Periclimenes cf. pauper Holthuis, 1951; Periclimenes sp.; Pseudocoutierea antillensis Chace, 1972; Tozeuma cf. cornutum Milne Edwards, 1881; and Trachycaris rugosa (Bate, 1888). A total of 1,418 specimens (including fragments) was obtained. The number of shrimp species per gorgonian ranged from 1-5; one gorgonian harbored 156 shrimps. The two predominant species, N. chacei and H. nicholsoni, occupy different mean depths (12.6 and 8.2 m, respectively). Sexual dimorphism assessed with Mann-Whitney U-tests was not apparent in the specimens of N. chacei (P > 0.05), but females of H. nicholsoni were significantly larger than males (P < 0.001). Minimum carapace length (CL, the tip of the rostrum to the posterior dorsal margin of the carapace) at which male N. chacei acquire a single appendix masculina spine is 1.25 mm; male H. nicholsoni can acquire a single spine at 0.9 mm CL. Histological sections of male N. chacei showed that shrimp with 0 or 1 spine are least likely to be mature. Female N. chacei can become ovigerous at 1.9 mm CL and female H. nicholsoni at 1.2 mm CL. The taxonomic status of 5 of the 9 species collected is uncertain.

Relationship Between BP (Baculovirus penaei) Energy Reserves in Larval and Postlarval Pacific White Shrimp Penaeus vannamei

The relationship between energy reserves of the penaeid shrimp Penaeus vannamei and Baculovirus penaei, or BP, were investigated in a series of experiments using mysis stage or early postlarval shrimp. Pre-exposure and post-exposure levels of protein and triacylgycerol (TAG) were determined. The effect of pre-exposure protein and TAG levels on susceptibility to BP infections was also investigated by starving a group of shrimp immediately prior to BP exposure. There was no consistent relationship between either pre-exposure or post-exposure protein levels and the percent of shrimp developing patent BP infections. There was, however, a significant positive correlation between TAG levels immediately prior to viral exposure and prevalence of infection 72 h later. Experimental reduction of TAG reserves prior to BP exposure delayed the development of a patent infection. In some, but not all, experiments there was a significant reduction in TAG levels of infected compared with uninfected shrimp 72 h post-exposure. The effect of patent BP infections on host TAG levels was subordinate to fluctuations in TAG content associated with the ontogeny of the hepatopancreas. Results of this study support histological observations that shrimp lipid levels can be altered by baculovirus infections. Furthermore, high levels of energy reserves in the form of TAG are associated with increased susceptibility to BP infection in larval and postlarval shrimp.

The Pathologic Copepod Phrixocephalus cincinnatus (Copepoda: Pennellidae) in the Eye of Arrowtooth Flounder, Atherestes stomias, and Rex Sole, Glyptocephalus zachirus, from British Columbia

We report Phrixocephalus cincinnatus, a pennellid copepod infecting the eyes of flatfishes, from a single specimen of rex sole, Glyptocephalus zachirus, for the first time. In the typical host, the arrowtooth flounder, Atherestes stomias, the parasite occurred commonly in sampled populations from the Broughton Archipelago in British Columbia, infected primarily the right eye of the flounder, and on only one occasion presented more than two parasites per eye. The copepod attached to the choroid layer and ramified throughout the posterior compartment of the eye, resulting in the disruption of the retina and probably impairing host vision. Inflammation and hyperplasia progressed to necrosis and proliferation of connective tissue, resulting in the total destruction of the eye.

[In Memoriam:] Vale Colin Dobson, 19 July 1937-22 June 2007

Obituary for Vale Colin Dobson, Australian parasitologists, 1937-2007.

Biology and Pathogenesis of the Coccidium Eimeria funduli Infecting Killifishes

Epizootics of Eimeria funduli involved estuarine killifishes (Fundulus grandis, F. pulvereus, F. similis, and F. heteroclitus) in Mississippi, Alabama, and Virginia. All of more than 500 specimens examined of F. grandis from Mississippi during 1977 through 1979 had infections, regardless of age, sex, or season collected. Oocysts occurred primarily in the liver and pancreas, replacing up to 85% of both those organs. Infrequent sites of infection were fatty tissue of the body cavity, ovary, intestine, and caudal peduncle. Living fish did not discharge oocysts. Eimeria funduli is the first known eimerian to require a second host. To complete the life cycle, an infective stage in the grass shrimp Palaemonetes pugio had to be eaten. In 6-mo-old killifish reared in the laboratory at 24 C, young schizonts were first observed in hepatic and pancreatic cells 5 days post feeding, followed by first generation merozoites by day 10, differentiation of sexual stages during days 15 to 20, fertilization between days 19 and 26, sporoblasts from days 25 to 30, and sporozoites about day 60. Unique sporopodia developed on sporocysts by day 35 when still unsporulated. Temperatures of 7 to 10 C irreversibly halted schizogony. Both schizogony and sporogony progressed slower as age of host increased. When infective shrimp in doses ranging from 1 to 10% of a fish's body weight were eaten, the level of intensity of resulting infections did not differ significantly. Pathogenesis followed a specific sequence, with the host response apparently unable to contend with extensive infections as seen typically in nature and in our experiments. Premunition was indicated. When administered Monensin® orally, infected fish exhibited a reduction in oocysts by 50 to 70% within 20 days as compared with untreated fish. Furthermore, infected killifish maintained exclusively on a diet of TetraMin® for 3 mo completely lost their infections.

Diatoms in the Gills of the Commercial White Shrimp

A white shrimp from Galveston, Texas, is the first reported case of a crustacean internally infected by a diatom. Even though more than one species occurred in debris on and between gill filaments, only individuals of Amphora sp. occurred within gills. To determine if a related diatom would easily reproduce within the shrimp and cause. a host response similar to that observed, we injected cultured specimens of A. coffaeformis into white shrimp. Under the experimental conditions, individuals of that species did not divide, but they elicited an extensive melanistic host-response.

Raphidascaris camura sp. n., Hysterothylacium eurycheilum (Olsen) comb. n. and Comments on Heterotyphlum Spaul (Nematoda: Ascaroidea) in Marine Fishes

Raphidascaris camura sp. n. infected the stomach and intestine of Pomatomus saltatrix (type host), from the northern Gulf of Mexico. It is characterized by having the following combination of features: 31 to 40 pairs of preanal papillae, 10 pairs of postanal papillae with the third papilla from the posterior extremity doubled, nearly equal spicules 1.8 to 2.7% of the body length, and lateral alae abruptly curved near their anterior extremity. Additional species of Raphidascaris were examined and are discussed. Hysterothylacium eurycheilum (Olsen, 1952) comb. n. (=Heterotyphlum e.) from Epinephelus itajara in Florida and the Lesser Antilles, previously known from female worms only, is redescribed as is the anterior end of Heterotyphlum himantolophi Spaul, 1927.

Food Content of Six Commercial Fishes from Mississippi Sound

Specific dietary contents from six fishes collected in Mississippi Sound are recorded. In order of their importance, primary components grouped in major taxonomic categories were fishes, penaeid shrimps, and other crustaceans for Cynoscion nebulosus; Crustaceans and fishes for C. arenarius; fishes and crustaceans for C. nothus; crustaceans, pelecypods, and polychaetes for Pogonias cromis; crustaceans, molluscs, polychaetes, and fishes for Archosargus probatocephalus; and fishes and penaeid shrimps for Paralichthys lethostigma. Principal items in the diets of most of the fishes included Anchoa mitchilli, Penaeus aztecus, P. setiferus, and Callinectes sapidus. Those crustaceans show that competition exists for commercial shellfishes in Mississippi Sound. Ratios among the different dietary items vary, according at least to species of fish, length of fish, season, specific location, and abundance of available prey. Some of these variations are documented and are additionally related to selected findings by other authors sampling different localities. We suggest that examination of food items in Archosargus probatocephalus can serve as a practical means to sample and assess seasonal prevalence and abundance of a wide range of invertebrates throughout different habitats in Mississippi Sound and elsewhere.

Haliotrema (Monogenea: Ancyrocephalinae) from Ostraciid Fishes in Guadeloupe, West Indies

Six sympatric species of Haliotrema Johnston and Tiegs, 1922 are described from ostraciid fishes in Guadeloupe, West Indies. All have a basic cone-shaped cirrus, but characteristics of that and other terminal genitalia plus those of anchors can differentiate them: H. guadeloupensis sp. n. from Lactophrys triqueter (typehost) and L. bicaudalis; H. torridum sp. n. from L. triqueter (type-host) and Acanthostracion polygonius; H. glandulosum sp. n. from L. triqueter (type-host) and L. bicaudalis; H. minutum sp. n. from A. polygonius; H. lactophrys (MacCallum, 1915) comb. n. from A. polygonius and A. quadricornis which is transferred from the genus Ancyrocephalus Creplin, 1839; and H. kritskyi nom. nov. from A. polygonius. The latter has been given a replacement name for Parahaliotrema brevis. Mizelle and Kritsky, 1969 which would become a junior homonym because it, H. affinis (Mizelle and Kritsky, 1969) comb. n., H. cornutus (M. and K.) comb. n., H. grandis (M. and K.) comb. n., H. pacificus (M. and K.) comb. n., and H. zebrasoma (M. and K.) comb. n. are all transferred from the genus Parahaliotrema Mizelle and Price, 1964. We follow others in considering that genus to be a junior synonym of Haliotrema. We also determined that at least Ancyrocephalus parupenei Yamaguti, 1968 and A. pauu Yamaguti, 1968 do not belong in Ancyrocephalus. However, investigation of H. australe Johnston and Tiegs, 1922 and other species should precede transferring those species to another genus.

Organization of Sporulated Oocysts of Eimeria funduli in the Gulf Killifish, Fundulus grandis

Oocysts of Eimeria funduli were studied by transmission electron microscopy in naturally-infected livers of the Gulf killifish, Fundulus grandis. Tissues were cryo-processed because membranous structures in the oocyst appear to hinder routine fixation and embedment. The oocyst wall (about 25 nm thick) was adjacent to the host cell and consisted of an outer membrane that limited the host cell cytoplasm and an inner membrane separated from the outer membrane by a narrow space. In some specimens, dense material was applied to the inner face of the inner membrane. Individual sporocysts were surrounded by a membranous "veil" (about 25 nm thick) that consisted of two unit membranes. Sporopodia, projections of the sporocyst wall, supported the veil. The sporocyst wall (130-150 nm thick) consisted of two layers, a thin electron-lucent outer layer (about 10 nm thick) and a thick electron dense inner layer (about 130 nm thick). Depending on the plane of section, the inner layer had transverse striations with periods of 3 to 4 nm or 12 to 15 nm. A narrow fissure, broadest at the anterior pole of the sporocyst, extended about one-third the length of the sporocyst wall. The posterior pole of the sporocyst was characterized by a bulbous swelling. Although this swelling resembled a Stieda body in light microscopic preparations, ultrastructurally, the swelling was a knoblike thickening in the sporocyst wall and did not plug a gap in this wall

Ultrastructure of the Interface Between Stages of Eimeria funduli/i> (Apicomplexa) and Hepatocytes of the Longnose Killifish, Fundulus similis

The interface between stages of Eimeria funduli and hepatocytes of the experimentally infected killifish Fundulus similis was studied ultrastructurally. Parasitophorous vacuoles (PV's) in which meronts, macrogamonts, and microgamonts developed were lined by an inner, smooth membrane and an outer, ribosome-studded membrane. The outer membrane bordered on the cytoplasm of the host cell, whereas the inner one limited the PV. The origins of these membranes have not been determined with certainty, but images were observed in which both membranes appeared to be continuous with the outer nuclear membrane of the host cell. Furthermore, the outer PV membrane was continuous with membranes of rough endoplasmic reticulum in the host cell. For stages which were rapidly growing or differentiating, the inner membrane blebbed into the PV. Blebbing ceased and ribosomes detached from the outer membrane after maturation of the meront or fertilization of the macrogamont. Blebbing appears to be a mechanism by which nutrients transfer from the host to the parasite. During sporogony, the inner PV membrane acquired a thin layer of electron dense material, but otherwise membranes lining the PV remained intact. The two PV membranes, probably together with dense material of parasitic origin lining the inner membrane, appear to serve as the oocyst wall enclosing the sporocysts until they are released in the intermediate host.

The Pentastomid Sebekia mississippiensis sp. n. in the American Alligator and Other Hosts

Sebekia mississippiensis sp. n. is described from Alligator mississippiensis in Louisiana, Mississippi, and Florida. Closely related to S. oxycephala in South American crocodilians, it differs by having a smaller and less spinous hook shield, a broader base for the posterior extensions of the oral cadre. and a thinner and more delicate tegument. The male reproductive system differs somewhat from that described for other pentastomids. Nymphs parasitize several fishes as well as turtles, snakes, and mammals.

Cathetocephalus thatcheri gen. et sp. n. (Tetraphyllidea: Cathetocephalidae) fam. n. from the Bull Shark

Cathetocephalus thatcheri gen. et sp. n. is described from the spiral valve of the bull shark, Carcharhinus leucas (Valenciennes), taken in the Gulf of Mexico and the Atlantic coast of Florida. A new family is erected for the new genus. The species most closely resembles Pillersium owenium Southwell, 1927, in that both possess a scolex which is perpendicular to the long axis of the strobila. It differs, however, in having a single neck and holdfast organ rather than a bifurcate neck with two bothridia. Also, the surfaces of the scolex differ from those of P. owenium by possessing fleshy papilliform structures on the leading and trailing edges rather than leaflike folds. Specimens with several strobilae are figured and discussed.