Observations sur les larves et les adultes de Carinariidae (Mollusca: Heteropoda) de l'Océan Atlantique Nord

Three species of Carinariidae were collected from the North Atlantic Ocean during the KN-38 cruise of the R.V. “Knorr”: Carinaria lamarcki Péron and Lesueur, 1810, Cardiapoda placenta (Lesson) 1830, and Cardiapoda richardi Vayssière, 1904. The characteristics of living specimens of larvae from all three species are described; shell morphology has been studied with the scanning electron microscope and internal anatomy from histological sections. The observations on C. placenta and C. richardi larvae are new. The specific characteristics of these larvae are tabulated. Particular attention is given to the morphology of an adult C. placenta and a juvenile C. richardi, with special emphasis on the shell and radula as studied with the scanning electron microscope.     

Taxonomic revisions in the marine biflagellate fungi: The ultrastructural evidence

The ultrastructure of the genera Althornia, Aplanochytrium, Japonochytrium, Schizochytrium and Thraustochytrium is described, and all are regarded as members of the new order Thraustochytriales Sparrow. Species considered are Althornia crouchii, Aplanochytrium kerguelensis, Hyalochlorella marina, Japonochytrium sp., Schizochytrium aggregatum, Thraustochytrium kinnei and T. striatum. All but H. marina are, on ultrastructural evidence, related genera, and some speculative suggestions are made about possible interrelationships both between the species discussed, between the Thraustochytriales and Labyrinthulales, and between these two and other major taxa.     

Studies on the family hemiuridae (Trematoda: Digenea), with a description of a new genus from marine fish of Indian waters

A new digenetic trematode, collected 1969–1970 at Ratnagiri (India) from the marine eel Leptocephalus conger, is described as Indostomachicola kinnei n. g., n. sp. The new genus differs from Stomachicola Yamaguti, 1934 and Allostomachicola Yamaguti, 1958 in many characteristics. The new species is characterized by an unlobed ovary, absence of receptaculum seminis, and presence of post-acetabular seminal vesicle and a ventral pit.     

Dispersal and use of sponges and ascidians as camouflage by Cryptodromia hilgendorfi (Brachyura: Dromiacea)

From May 1977 to February 1979, the use of sponges and ascidians by Cryptodromia hilgendorfi was studied in Moreton Bay, Queensland, Australia. The aim was to investigate patterns of seasonal use, cap making behaviour, cap turnover, the effect of intraspecific interactions on cap life and the effect of movement of crabs between hosts on background matching. C. hilgendorfi uses 12 (of 16 available) species of sponge and 3 species of ascidians to construct caps, which are carried by the crabs using their last two pairs of legs. Cap area increases non-linearly with crab size, and caps are normally two to three times as large as the crabs. Cap making behaviour is described. It occurs during intermoult periods, with females making most of their caps at night. Caps decrease in size with time, but conceal the crabs which commonly occupy exposed sites on sponges. Cap life is independent of crab size, differs between different cap species and is influenced by the presence of other crabs who can dislodge caps through aggressive behaviour. Caps are made from the sponge Suberites carnosus more often than from other available sponges. S. carnosus caps also decay less rapidly than caps made from other sponges. Use of sponge and ascidian species varies seasonally, with Halichondria sp. and S. carnosus being used in all months. C. hilgendorfi exhibits a preference for certain sponges. The majority of crabs carried caps which matched their host sponge or ascidian, but mis-matches varied seasonally with a winter peak following the breeding season. Young C. hilgendorfi settle only on S. carnosus sponges and disperse from this host to other species in the environment. Males and females differ in their rate of discovery of new hosts. Males, despite their greater mobility, find new hosts slower than females. It is hypothesized that males occupy “home ranges” which females do not. Crabs frequently move between sponges, mostly at night. Sponges and ascidian species grow in intimate association with each other, and sponge crabs act a selective asexual propagation mechanism. Depending upon the nature of the interactions between sponge and ascidian species (co-operative or competitive) and whether competitive hierarchies or networks are involved, the sponge crabs may have either stabilizing or destabilizing effects on the sponge community.     

Systematic status of two oyster populations of the genus Tiostrea from New Zealand and Chile

A systematic examination of Tiostrea chilensis endemic to the Pacific coast of South America and of T. lutaria endemic to new Zealand was conducted using protein-gel electrophoresis. Also, ecological and life-history traits were compared between these two documented species. Our study revealed that although three different ecomorphs could be distinguished from various environmental and ecological conditions, the life-history traits between the two species were remarkably similar. Estimates were made of levels of genetic variation and similary based on 29 structural loci among individuals from each documented species. The percentage of loci polymorphic was estimated at 17.2 and 17.6, while the percentage of loci heterozygous was 2.1 and 6.7 for T. chilensis and T. lutaria, respectively. The genetic similarity between the two species was computed as 0.991, where 1.0 indicates no genetic difference among structural loci. The overwhelming evidence of this study indicates that T. chilensis and T. lutaria are different geographical populations of one species and by priority this species should be T. chilensis.     

Hexabathynella halophila gen. n., sp. n. und die Frage nach der marinen Abkunft der Bathynellacea (Crustacea: Malacostraca)

All species of Bathynellacea, known to occur in the immediate vicinity of the sea, belong to the same genus, Hexabathynella gen. n. The species are: H. pauliani, H. knoepffleri, H. tenera. Also included into the new genus are the fresh-water species H. hebrica, H. szidati, H. minuta. To these, a new species, H. halophila sp. n., is added; it was found at a salinity of 27‰ and is the first representative of the Bathynellacea recorded from polyhaline waters. A simple experiment revealed that the new species is likely to be extremely euryhaline. Current opinion as to the marine origin of the Bathynellacea is criticized in the light of new evidence resulting from recent studies on the evolution and systematic relationships within this order. Contrary to common belief, the Bathynellacea did not colonize the fresh-water mesopsammal via the mesopsammal of marine sandy beaches. The extant Bathynellacea most likely derived from ancestors which lived in fresh-water lakes or running surface waters. They became distributed in their mesopsammal habitat. The occurrence of some species of Hexabathynella gen. n. in oligohalime to polyhaline waters is secondary.     

Competition for food and other niche-related studies of three species of salt-marsh foraminifera

The niches of 3 species of salt-marsh foraminifera, Allogromia laticollaris, Rosalina leei, and Spiroloculina hyalina were assessed in the laboratory. The 3 species reproduce within the following ranges: temperature (10° to 33°C), salinity (12 to 45‰) and pH (5 to 10). Competition for food among the 3 species was evaluated. S. hyalina did not compete with other species. Intraspecific competition (crowding) appears to be an important factor limiting the reproduction of A. laticollaris. Crowding seems to have little effect on the other 2 species. The feeding of foraminifera is affected by the quality and quantity of food organisms. The feeding rate of the species tested is directly related to concentration within a range of 10² to 10⁶ cells fed. S. hyalina is a bacterial feeder. A. laticollaris is a rare species which may become locally abundant when dominant species are missing. S. hyalina is also a rare species, which can bloom where the density of bacteria is relatively high and in the absence of competing species. R. leei is a stable, conspicuous species, whose moderate numbers are relatively unaffected by physical stress and competition. Some new laboratory data on Ammonia beccarii were obtained so that this species could be compared with the other studied. Differences in niches are graphically presented.     

Live discrimination of Calanus glacialis and C. finmarchicus females: can we trust phenological differences?

Two key players in the Arctic and subarctic marine ecosystem are the calanoid copepods, Calanus finmarchicus and C. glacialis. Although morphologically very similar, these sibling species have different life cycles and roles in the Arctic pelagic marine ecosystem. Considering that the distribution of C. glacialis corresponds to Arctic water masses and C. finmarchicus to Atlantic water masses, the species are frequently used as climate indicators. Consequently, correct identification of the two species is essential if we want to understand climate-impacted changes on Calanus-dominated marine ecosystems such as the Arctic. Here, we present a novel morphological character (redness) to distinguish live females of C. glacialis and C. finmarchicus and compare it to morphological (prosome length) and genetic identification. The characters are tested on 300 live females of C. glacialis and C. finmarchicus from Disko Bay, western Greenland. Our analysis confirms that length cannot be used as a stand-alone criterion for separation. The results based on the new morphological character were verified genetically using a single mitochondrial marker (16S) and nuclear loci (six microsatellites and 12 InDels). The pigmentation criterion was also used on individuals (n = 89) from Young Sound fjord, northeast Greenland to determine whether the technique was viable in different geographical locations. Genetic markers based on mitochondrial and nuclear loci were corroborative in their identification of individuals and revealed no hybrids. Molecular identification confirmed that live females of the two species from Greenlandic waters, both East and West, can easily be separated by the red pigmentation of the antenna and somites of C. glacialis in contrast to the pale opaque antenna and somites of C. finmarchicus, confirming that the pigmentation criterion is valid for separation of the two species.     

Third-stage larva shifts host fish from teleost to elasmobranch in the temporary parasitic isopod, Gnathia trimaculata (Crustacea; Gnathiidae)

The life cycle of the fish ectoparasitic isopod Gnathia trimaculata is described based on both field samplings and laboratory observations. Species identification of the larvae was based on morphological observation and supported by molecular analysis. As the results of field samplings in several sites of southwestern and central Japan (24–34°N, 124–139°E) from 2005–2011, approximately 900 third-stage larvae of G. trimaculata were found on 25 elasmobranch species, and 220 first- and second-stage larvae were found on three teleost species. No third-stage larvae were found on the teleosts, and the larvae of younger stages never infested elasmobranchs. Therefore, G. trimaculata is supposed to shift its host from teleosts to elasmobranchs as it develops. We discuss the developmental periods, life span, distribution, and predation risk of the present species compared with other gnathiid species.     

Developmental and genetic evidence for the existence of three morphologically cryptic species of<Emphasis Type="Italic"> Crepidula</Emphasis> in northern Chile

The taxonomy of Crepidula has been based principally on shell morphology, but shell characteristics in this genus may be strongly influenced by the substrates they inhabit and are thus of limited use in classification. Four species in this genus are currently recognized from the Chilean coast, of which two, Crepidula dilatata and C. fecunda, are sympatric. These species are morphologically cryptic and differ only in their larval development: C. dilatata has indirect development with a planktonic phase, and C. fecunda direct development within egg capsules. The other two species, C. coquimbensis and C. philippiana, are species that occur within gastropod shells inhabited by hermit crabs and differ from the other species in internal morphology of the shell, developmental features, and geographic distribution. Analyses of nine morphological characters, eight developmental characters, and 26 enzymatic loci were carried out on four Crepidula populations in the Coquimbo region of northern Chile. Four populations of Crepidula were identified based on morphological, developmental, and protein electrophoresis features. Our results suggest the presence of C. coquimbensis plus three morphologically cryptic species including C. dilatata, C. fecunda, and a new previously unrecognized cryptic species. All four populations showed differences in larval development pattern. C. fecunda have indirect development, with free-swimming larvae. The remaining three species have intracapsular metamorphosis, but different modes of larval nutrition. C. dilatata have nurse eggs that are consumed by mechanical destruction; C. coquimbensis engulf nutritional embryos; and the new species eat nutritive embryos by rotation. Protein electrophoresis data support the specific condition of each group with different larval development and endorse the use of developmental differences in taxonomy of Crepidula. Genetic distance shows that C. dilatata and C. fecunda are closely related, and that C. coquimbensis is closer to them than to the new cryptic species.     

Ein priapulide mit kleptocniden aus dem adriatischen meer

The surprising find of a single priapulid specimen off Rovigno (Istria, Jugoslavia) is the first record of a representative of this group in the Adriatic Sea; it is the second record of Priapulida in the Mediterranean Sea. The presence of cleptocnids, concentrated in scattered epidermic hills is unique, and leads to the establishment of the new species Priapulopsis (?) cnidephorus. The species is described; it possesses a longitudinal duct within the 8 double-layered, septa-like introvert retractor-muscles (Fig. 5).     

Shifts of the feeding niche along the size dimension of three juvenile fish species in a tidal mudflat in southeastern Brazil

The diet of three cooccurring abundant fish species (Eucinostomus argenteus, Diapterus rhombeus and Micropogonias furnieri) and its ontogenetic changes in a mudflat area of a tropical bay in southeastern Brazil were described. The working hypothesis is that these three species shift the use of the available resources throughout their growth. Early juveniles of D. rhombeus and M. furnieri fed mainly on Cyclopoida copepods, shifting to Nematoda (D. rhombeus) and errant Polychaeta (M. furnieri) as they increased in size. In contrast, the early life stages of E. argenteus fed mainly on errant Polychaeta and Calanoida copepods, with increasing niche breadth as they grew. The relative degree of individual specialisation in resource use indicated specialism for M. furnieri and E. argenteus, and generalism for D. rhombeus. The largest intraspecific overlap was found for the smallest size classes. Niche breadth increased during ontogeny, with a higher average niche breadth at lower prey length/predator length ratios. Therefore, species-specific differences in diet across the resource gradient and increased niche breadth during ontogeny characterised the shifts of resource use, and probably account for the coexistence of these species in zones of sympatry in mudflat areas of southeastern Brazil.     

Etude de la respiration chez des copépodes de niveaux bathymétriques variés dans la région sud marocaine et canarienne

The results of 281 respiration analyses of pelagic copepods sampled in the South Moroccan and Canarian area are described. The copepods used in experimentation were collected from various bathymetric levels: hyponeustonic species (Anomalocera patersoni, Pontellopsis villosa, P. regalis, Labidocera wollastoni, Pontella lo biancoi), epipelagic species (Centropages typicus, Temora stylifera, Calanus helgolandicus, Acartia clausi), meso and bathypelagic species (Pleuromma xiphias, P. abdominalis, Euchaeta acuta, Undeuchaeta plumosa and some other rare species). Analysis of the metabolismtemperature curve makes it possible to describe different modes of adaptation in relation to geographical distribution, altitudinal repartition, and dietary characteristics. When all species are studied together, a strong correlation exists between the log of respiration and the log of weight. The regression coefficient varies with temperature; it is strongest at a temperature near that of the natural thermic conditions.     

Reef coral reproduction in the eastern Pacific: Costa Rica, Panamá and Galápagos Islands (Ecuador). IV. Agariciidae, recruitment and recovery of Pavona varians and Pavona sp.a

The reproductive ecology of two eastern Pacific zooxanthellate coral species was examined as part of a continuing series of studies relating bleaching/mortality events caused by the El Niño–Southern Oscillation disturbance, and is described for study sites in Costa Rica, Panamá, and the Galápagos Islands (Ecuador). This study deals with the sibling agariciid species Pavona varians and Pavona sp.a over a 13?yr period (1985 to 1997). Both Pavona species are broadcast-spawners with some gonochoric, but mostly sequential hermaphroditic colonies. Minimum colony sizes (and ages) at first reproduction were 5?cm (5?yr) and 3?cm (2 to 3?yr), respectively, in P. varians and Pavona sp.a. In the Panamá and Galápagos populations, gonochoric colonies spawn eggs or sperm at least monthly. Six fecundity attributes were not significantly different in the two species, but the eggs of P. varians are white to beige and positively buoyant, and those of Pavona sp.a are dark green and neutrally to negatively buoyant. Eggs of both species lack zooxanthellae. Both species are reproductively active year-round, with maximum activity in the dry season in the nonupwelling Gulf of Chiriquí, and in the wet season in the upwelling Gulf of Panamá. Spawning is predominantly during full moon, and possibly also at new moon at most study sites. Spawning in P. varians and Pavona sp.a is 12?h out of phase, with the former species spawning ～1?h before sunrise and the latter about 1?h after sunset. The fecundity of Pavona spp. at Caño and the Galápagos Islands was much greater (19?900 to 27?900 eggs cm^?2?yr^?1) than at all Panamá sites (14?800 to 19?800 eggs cm^?2?yr^?1). Intraspecific crosses in both species resulted in swimming planula larvae after 25 to 36?h. Recruitment of P. varians was highest in Panamá, moderate in Costa Rica, and nil in the Galápagos Islands, matching, respectively, the contributions of P. varians to the pre-1982/1983 El Niño coral-population abundances in these areas. Recruitment success of P. varians at Uva Island was significantly related to maximum monthly positive sea surface-temperature (SST) anomalies that occurred in the year preceding recruitment over the period 1982 to 1996; recruitment failed when SST anomalies exceeded 1.6 to 1.9?C° during the severe ENSO events of 1982/1983 and 1997/1998.     

Failure to confirm previous identification of two putative museum specimens of the Atlantic sturgeon, Acipenser sturio, as the Adriatic sturgeon, A. naccarii

MtDNA analyses were employed to examine the species identification of three preserved museum sturgeon specimens from the River Guadalquivir, two of which were originally described as Acipenser sturio L., 1758 by Hernando (1975; Doñana, Acta Vertd 2: 263–264). Later the same two specimens were identified as A. naccarii Bonaparte, 1836 by Garrido-Ramos et?al. (1997; Mar Biol 129: 33–39) on the basis of morphometric and nuclear DNA analyses. Three different laboratories using independent techniques were unsuccessful in extracting authentic DNA from tissue samples from the three specimens and in obtaining any verifiable PCR product. We cannot confirm the previous molecular identification of two of these specimens by Garrido-Ramos et?al. as A. naccarii. We suggest that these specimens are indeed A. sturio.     

Les appendiculaires du Golfe du Bengale

Appendicularians from 76 hauls made from June to August 1964 in the Bay of Bengal, aboard the R. V. “Kistna”, have been examined. Of the 26 species determined, 10 are new for the Bay of Bengal and, amongst these, 2 were unknown in the Indian Ocean. The composition of the group formed by the most abundant and most frequent species is characteristic of the fauna of the Indian Ocean. Oikopleura longicauda represents 50% of the total number of individuals collected, followed by O. rujescens 14%, Megalocerus huxleyi 8%, O. fusiformis and Fritillaria borealis f. sargassi 6%, O. cophocerca and Stegosoma magnum 2%. No other species reached 1%. The density of the species in the occidental zone deereased fairly regularly with latitude: 21 species in the south, then going on towards the north, 14, 11 and 2. In the area south of the strait of Malacca only 5 species were found, in its opening into the Bay of Bengal, 18. The Oikopleuridae were present in all the hauls, but the Fritillaridae were absent from 25. The geographical distribution of each species has been studied. Oikopleura longicauda is the only one which is clearly more abundant in the north; most of the other species show a decreasing gradient from south to north. The characteristic difference between the different zones cannot be established from the hydrological data (temperature and salinity). It seems, therefore, that the indigenous species are not very common, and that others originate from the Indian Ocean, transported by the south-north currents present at that time of year.