Academic literature on the topic 'Nassarius dorsatus'

Two new Stephanostomum-like cercariae, Cercaria capricornia VII and Cercaria capricornia VIII (Digenea: Acanthocolpidae), are described from the nassariid gastropods Nassarius dorsatus and Nassarius olivaceus collected from the intertidal zone in the Capricornia region of Central Queensland, Australia. Morphological analysis of these new cercariae was augmented with DNA sequence data from the large subunit (LSU) ribosomal DNA region to aid in identification. Bayesian inference analysis of the LSU rDNA revealed that these putative acanthocolpid cercariae nested well within a clade containing species of Stephanostomum, which along with morphological data, suggests they are species of Stephanostomum. Comparative analysis of LSU rDNA sequences also indicates that these two cercariae are not S. adlardi, S. bicoronatum, S. tantabiddii or S. cf. uku, all species known from Australian fishes. The secondary structure of the internal transcribed spacer 2 (ITS2) rDNA region was inferred for these two cercariae using minimum free energy modelling algorithms. Both cercarial types displayed a four helix ITS2 secondary structure model and differed from each other by two compensatory base changes (CBCs) and nine hemi-CBCs.

Cercariae capricornia I–VI, six new cercariae putatively identified as belonging to the Acanthocolpidae, are described and named from prosobranch gastropods of the family Nassariidae collected from the intertidal zone in the Capricornia region, Central Queensland, Australia. Four species are reported from Nassarius olivaceus and two from N. dorsatus. The cercariae have a unique and complex three-dimensional body shape, including a keel, which differentiates them from previously described acanthocolpid cercariae. These are the first cercariae to be described from these gastropods.

Background: Seagrasses are flowering plants (Angiosperms) that are able to adapt fully in waters with high salinity or live immersed in water. Seagrass has true rhizomes, leaves and roots like plants on land. Seagrasses usually form fields called seagrass beds, especially in tropical and sub-tropical regions. The existence of seagrasses is known to support fishing activities, shellfish communities and other invertebrate biota. Method: This study is a descriptive study to reveal information about environmental characteristics, and associations of seagrasses with gastropods. Results: The study found a class of gastropods, 10 species namely Strombus variabilis, Strombus microurceus, Nassariusl uridus, Nassarius dorsatus, Strombus urceus, Cypraea annulus, Strombus labiatus, Strombus marginatus, Neritas quamulata, Cypraeratigris. Of the seagrass plants found 4 species, namely Enhalus acoroides, Thalassia hemprichii, Halophila ovalis, Cymodocea rotundata. Association values ​​ranged from 4.159-8.85 with positive and negative types. This means that both types of seagrass are often found together or not found together in each observation box. Conclusion: There is a weak association between seagrass and gastropods in the coastal waters of Tiouw State. The association of gastropod types with seagrass species is found in 10 types of gastropods and 4 types of seagrasses in the waters of the Tiouw State coast

Gastropod is one the mollusk phylum that can adapted at the mangrove ecosystem. Gastropod are organisms that have an ecological role as forming detritus. The study aimed to examine species diversity of gastropods in the mangrove forest ecosystem of Sebubus Village, Paloh District, Sambas Regency. The study was conducted in April 2019, using the survey method. Observations found 6 families and 16 species of gastropods in the mangrove ecosystem. Gastropods species are Chicoreus capucinus, Nerita balteata, Neritina cornucopia, Nerita violacea, Cerithideopsilla alata, Cerithidiopsis quoyii, Cerithidea obtusa, Littoraria scabra, Littoraria undulata, Littoraria carinifera, Nassarius dorsatus, Cassarius dorsatus, Cassidula aurisfelis, Ellobium aurisjudae, Cassidula nucleus, Pythia plicata, and Ellobium gangeticum. Species diversity index of gastropod in zone 1 = 0.83, zone 2 = 0.73 and zone 3 = 0.79 in the low category. Species abundance index of gastropod in zone 1 = 15.3, zone 2 = 10.5, zone 3 = 15.8. Species evenness index of gastropod in zone 1 = 0.32, zone 2 = 0.30 and zone 3 = 0.30 categorized as low. Species dominance index of gastropod in zone 1 = 0.20, zone 2 = 0.28 and zone 3 = 0.25 are categorized as low. Species similiarity index of gastropod in zone 1 and 2 = 91.67%, zone 2 and 3 = 80.00%, zone 1 and 3 = 81.48 are categorized very high.Keywords: Diversity, Gastropods, Mangrove Ecosystems

"The biodiversity and ecology of marine cercariae in Australia is poorly known. Although nassariid gastropods are widely distributed in Australia and are expected to have a diverse parasite fauna similar to that of other nassariids worldwide, their cercariae have not been characterised. Nassarius dorsatus, N. olivaceus and N. pullus were collected at three separate estuarine localities in central Queensland between August 2004 and August 2006 and their emergent cercariae characterised using morphological and molecular methods. Fifteen morphotypes of cercariae from six families that infect fishes and birds as definitive hosts were characterised. The highest richness was within the Acanthocolpidae (nine morphotypes) which comprised three cercariae interpreted as species of Stephanostomum and a complex of six unusual cercariae with a ventral keel. Molecular characterisation of these six cercariae supported their placement in the Acanthocolpidae and indicated that they comprised only three species, two of which displayed marked phenotypic plasticity. Molecular analysis supported the characterisation of the three species of Stephanostomum and suggested that one of the unusual cercariae was a species of Stephanostomoides. Dissection of fish from Sandy Point provided a single match; the sequence for a metacercaria in Valamugil buchanani, the blue-tail mullet, was identical to that of one of the species of Stephanostomum. There were two cercariae from the Echinostomatidae and one from each of the Lepocreadiidae, Microphallidae, Opecoelidae and Zoogonidae. Molecular analyses supported the placement of the cercariae from the Echinostomatidae, Lepocreadiidae, Opecoelidae and Zoogonidae within their respective families. The cercaria from the Lepocreadiidae was identified by comparison to known adult data and putatively corresponds to Prodistomum keyam, a parasite of Monodactylus argenteus, the silver moony or butter bream, common in the study region. Morphological analysis supported the characterisation of both of the Echinostomatidae as species of Himasthla. Although no other cercariae could be characterised to genus level, the opecoelid cercaria was determined to be in the subfamily Opecoelinae. Nassarius olivaceus was infected by three acanthocolpid cercariae and one cercaria from each of the other families. Nassarius dorsatus was infected by five acanthocolpid cercariae and one each from the Echinostomatidae and Lepocreadiidae. Nassarius pullus was infected by a single cercaria from the Echinostomatidae. Most cercariae were specific to a single species of gastropod; only four infected two species and none infected all three. Cercariae that infect fish as a definitive host were found at all three localities; but cercariae that infect birds were restricted to a single locality, Sandy Point at Corio Bay, important for domestic and migratory bird species. These results emphasise the relative significance of Sandy Point as an important bird habitat. In total, 126 infections were diagnosed (115 by cercarial emergence), with both the highest frequency of infection and number of infections in N. olivaceus (frequency 5.3%; n=102; 81% of infections), followed by N. dorsatus (1.1%; 20; 16%) and N. pullus (0.2%; 4; 3%). The highest number of infections occurred at Sandy Point (66; 52% of infections), followed by Cawarral Creek (38; 30%) and then Ross Creek (22; 17%). The highest number of infections was by the Acanthocolpidae (54; 43%). Diagnosis of infection by emergence was suitable for all cercariae except the opecoelid, which was underdiagnosed. Nassarius olivaceus had the longest survival in captivity (~4.5 y), followed by N. dorsatus (~0.8 y) and N. pullus (~0.3 y). Almost all infections remained patent for the life of the gastropod. Families commonly found in nassariids worldwide include Acanthocolpidae, Echinostomatidae, Lepocreadiidae and Zoogonidae. Nassariid gastropods are also the dominant marine first intermediate hosts for the Acanthocolpidae, Lepocreadiidae and Zoogonidae and one of the three most common first intermediate host families for species of marine Himasthla. Molecular relationships also indicate that the Acanthocolpidae and Brachycladiidae may actually be comprised of three discrete groups, the Stephanostomum + Monostephanostomum group, the Brachycladiidae, and a group of non-Stephanostomum species comprising Pleorchis, Tormopsolus and Stephanostomoides. This research adds information about the parasite assemblages of nassariid gastropods in Australia, adding 12 new cercarial species and 16 new host-parasite records. Cercarial reports for the Acanthocolpidae, Echinostomatidae, Lepocreadiidae, Opecoelidae and Zoogonidae have been comprehensively reviewed and patterns of association between nassariids and their common parasite families presented. As well, this research has provided a potential avenue for a review of the Acanthocolpidae, a family which is currently considered a ‘catch-all’ group."