Morphology and Systematics of the Nemertean Pseudocarcinonemertes homari (Hoplonemertea:Mortostilifera) from the American Lobster, Homarus americanus

1985 ◽  
Vol 42 (2) ◽  
pp. 342-350 ◽  
Author(s):  
L. S. Uhazy ◽  
D. E. Aiken ◽  
A. Campbell
Keyword(s):  
Developmental Stages ◽  
Morphological Characteristics ◽  
Original Description ◽  
Homarus Americanus ◽  
Bay Of Fundy ◽  
American Lobster ◽  
Free Living ◽  
The Family ◽  
Passamaquoddy Bay ◽  
Stylet Length

Our study of the morphology and systematics of the nemertean Pseudocarcinonemertes homari Fleming and Gibson, 1981 is based on specimens removed from the damaged egg masses of American lobsters, Homarus americanus, caught in the type locality at Grand Manan, N.B., in the Bay of Fundy and nearby Passamaquoddy Bay. Morphological characteristics and measurements of males, females, and developmental stages, obtained through examination of live and preserved nemerteans plus stained histological sections, revealed differences and provided additional indications of variability in measurements of taxonomic characters when compared with the original description. Specifically, female nemerteans are longer and slightly wider than males; the rhynchodael opening is subterminal; sensory bristles occur lateral to the rhynchodael and anal openings; cephalic furrows are observable on living specimens; the combined stylet–basis length is longer than reported and stylet length appears a stable character; the bulbous or sacculate foregut joins to a distinct pyloric tube; ova are large, 260 × 251 μm in length and width; and larvae retained in the membranous brood sac lack anterior and posterior cirri or tufts. Comparison of characters that define Pseudocarcinonemertes and differentiate it from Carcinonemertes with those defining free-living hoplonemerteans strongly supports its removal from the family Carcinonemertidae to the family Tetrastemmatidae.

scholarly journals Description of a new genus and species of Chrysopetalidae (Annelida: Polychaeta) from the NE Atlantic, with some further records of related species

2019 ◽  
Author(s):  
Ascensão Ravara ◽  
M. Teresa Aguado ◽  
Clara F. Rodrigues ◽  
Luciana Génio ◽  
Marina R. Cunha
Keyword(s):  
Dna Sequences ◽  
New Genus ◽  
Morphological Characteristics ◽  
Mantle Cavity ◽  
Full Description ◽  
Gulf Of Cadiz ◽  
Ne Atlantic ◽  
Free Living ◽  
The Family ◽  
Gulf Of Cádiz

Five chrysopetalid species are reported from samples collected at bathyal depths in three NE Atlantic regions: the Bay of Biscay, the Horseshoe Abyssal Plain and the Gulf of Cadiz. Arichlidon reyssi (Katzmann et al., 1974), Dysponetus caecus (Langerhans, 1880) and D. profundus Böggemann, 2009 are free-living forms found mainly on biogenic substrates (e.g., coral and sunken wood). A brief description and taxonomical remarks are given for each of these species and their geographical distributions and habitat records were updated accordingly. Natsushima bifurcata Miura & Laubier, 1990 and Craseoschema thyasiricola gen. et sp. nov. are symbionts inhabiting the mantle cavity of chemosynthesis-based bivalves known from four mud volcanoes from the Gulf of Cadiz. Craseoschema thyasiricola gen. et sp. nov. was found inside a thyasirid bivalve and presents mixed morphological characteristics of free-living and symbiotic forms within Calamyzinae Hartmann-Schröder, 1971. A full description of the new species is given together with DNA sequences of the genes COI, 16S and H3 that were used in a phylogenetic analysis to indicate the position of the new genus within the family.

Morphometrics of American Lobster (Homarus americanus) Larvae in Relation to Stock Determinations in the Maritimes, Canada

1993 ◽  
Vol 50 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Gareth Harding ◽  
Ellen Kenchington ◽  
Zhensui Zheng
Keyword(s):  
Management Practices ◽  
Gulf Of Maine ◽  
Function Analysis ◽  
Morphological Characteristics ◽  
Homarus Americanus ◽  
American Lobster ◽  
Past Century ◽  
Enzyme Electrophoresis ◽  
Larval Size ◽  
Cape Breton

Morphological characteristics of the first larval stage of the American lobster (Homarus americanus) enabled the separation of the Maritime population with stepwise discriminant function analysis into three groups: the southern Gulf of St. Lawrence and its outflow around Cape Breton Island, the Atlantic inshore region of Nova Scotia, and the offshore banks bordering the Gulf of Maine. Once the effect of environmental temperature on larval size was removed, the differences between Georges and Browns banks and the Atlantic inshore disappeared. The remaining differences, chiefly in the dimensions of the second and fifth abdominal segments and the rostrum, between larvae from the Cape Breton sites and elsewhere may be due to other environmental factors or partial genetic isolation. Conservation and management practices over the past century have increased gene flow between regions, and most of this appears to be from the release of Gulf of St. Lawrence lobsters in the Gulf of Maine. A reassessment of previous studies on adult morphology, benthic movements, larval dispersal, enzyme electrophoresis, and commercial landing patterns supports the separation of the Gulf of St. Lawrence stock from the rest of the Canadian Maritimes.

Two new and one known species of Phanodermatidae (Nematoda: Enoplida) from Sagami Bay, Japan

Zootaxa ◽  
2019 ◽  
Vol 4608 (3) ◽  
pp. 484
Author(s):  
DAISUKE SHIMADA ◽  
KEIICHI KAKUI
Keyword(s):  
Marine Biology ◽  
North Pacific Ocean ◽  
Original Description ◽  
Morphological Characters ◽  
Marine Nematode ◽  
Sagami Bay ◽  
Free Living ◽  
The Family ◽  
Species Lists ◽  
Arctic Russia

Two new and one known species of free-living marine nematode belonging to the family Phanodermatidae are described. They were collected during the 12th Japanese Association for Marine Biology (JAMBIO) Coastal Organism Joint Survey off Jogashima, Japan in Sagami Bay, North Pacific Ocean. Phanodermopsis kohtsukai sp. nov. differs from the congeners by the shape of the tail, the longer spicules, and the absence of the gubernaculum. Micoletzkyia nakanoi sp. nov. differs from the congeners by the absence of a circle of cervical setae, the proportion of the tail, the cylindrical gubernaculum without projection, and the position of the vulva. Crenopharynx caudata (Filipjev, 1927) comb. nov. is transferred from the genus Phanodermopsis based on the presence of the long spicules. The morphological characters of the newly collected specimens of C. caudata comb. nov. are in excellent agreement with those shown in the original description of the specimens from Arctic Russia and the previous redescription of the specimens from Skagerrak. The new diagnoses and species lists for these three genera and two dichotomous keys to the males of Micoletzkyia and Crenopharynx are provided. 

scholarly journals First Report of Meloidogyne enterolobii on Arrowroot in China

Plant Disease ◽  
2010 ◽  
Vol 94 (2) ◽  
pp. 271-271 ◽  
Author(s):  
K. Zhuo ◽  
M. X. Hu ◽  
J. L. Liao ◽  
K. Rui
Keyword(s):  
Morphological Characteristics ◽  
Original Description ◽  
First Record ◽  
Reproduction Rate ◽  
Enzyme Electrophoresis ◽  
Species Identity ◽  
Root Knot Nematodes ◽  
Meloidogyne Enterolobii ◽  
The Family ◽  
Lateral Lines

The rhizome of arrowroot (Maranta arundinacea L.) is used as a source of edible starch in many tropical/subtropical areas. In July 2009, cultivated arrowroot plants in a field in Haikou, Hainan Province, China were observed to be exhibiting symptoms of decline, including stunting and yellowing. Roots of affected plants were found to have severe root galling similar to that caused by root-knot nematodes. Meloidogyne sp. females were dissected from the galls. Morphological characteristics of the females fit the description of M. enterolobii Yang & Eisenback (4). The perineal patterns were variable, with moderately high to high dorsal arch and mostly lacking lateral lines, but when present, the lines were not conspicuous, similar to those in the original description.(4). For further confirmation of species identity, isoenzyme patterns of malate dehydrogenase (Mdh) and esterase (Est) phenotypes were analyzed and partial sequences of mtDNA were obtained. Enzyme electrophoresis showed that the phenotypes of Mdh and Est were N1a and VS1-S1 respectively, which were consistent with those of M. enterolobii (1). Amplification and sequencing of the mtDNA between COII and the lRNA gene was accomplished with primers C2F3 (5′-GGTCAATGTTCAGAAATTTGTGG-3′) and 1108 (5′-TACCTTTGACCAATCACGCT-3′) (2). A DNA fragment of 705 bp was obtained and the sequence (GenBank Accession No. GQ870255) was compared with those in GenBank. A BLAST search indicated the sequence was 100% identical to the sequences of M. mayaguensis (GenBank Accession Nos. AY446969 and AY446970), a synonym of M. enterolobii (3). On the basis of these results, the root-knot nematodes isolated from arrowroot in Hainan were confirmed as M. enterolobii. This species has a high reproduction rate and a wide host range; moreover, it can induce severe galling and is able to overcome the resistance gene Mi-1 in tomato and pepper (4). M. enterolobii has become increasingly important because it has been found in many countries on diverse hosts. In China in recent years, the nematode has been reported on approximately 20 plant species belonging to five families, including Fabaceae, Cucurbitaceae, Solanaceae, Myrtaceae, and Annonaceae. To our knowledge, this is the first record of M. enterolobii parasitizing a plant (i.e., arrowroot) in the family Marantaceae in China. References: (1) P. R. Esbenshade and A. C. Triantaphyllou. J. Nematol. 17:6, 1985. (2) T. O. Powers and T. S. Harris. J. Nematol. 25:1, 1993. (3) J. Xu et al. Eur. J. Plant Pathol. 110:309, 2004. (4) B. Yang and J. D. Eisenback. J. Nematol. 15:381, 1983.

Geographic Distribution and Seasonal Occurrence of the Nemertean Pseudocarcinonemertes homari on the American Lobster, Homarus americanus

1985 ◽  
Vol 42 (2) ◽  
pp. 360-367 ◽  
Author(s):  
J. Brattey ◽  
A. Campbell ◽  
A. E. Bagnall ◽  
L. S. Uhazy
Keyword(s):  
Homarus Americanus ◽  
Bay Of Fundy ◽  
American Lobster ◽  
Wild Populations ◽  
Intensity Of Infection ◽  
Egg Masses ◽  
Mean Intensity ◽  
Life History Stages ◽  
Egg Incubation ◽  
The Impact

Examination of 1041 trap-caught lobsters from the Bay of Fundy, Grand Manan, Browns and German Banks, south and east Nova Scotia, and Northumberland Strait indicated that Pseudocarcinonemertes homari occurs on American lobsters, Homarus americanus, throughout Canadian Maritime waters. Male lobsters were rarely infected and ovigerous females generally had a higher prevalence (percentage infected) and mean intensity of infection (number of nemerteans per infected lobster) than nonovigerous females. Sexually immature nemerteans were found on male and nonovigerous female lobsters, but all P. homari life history stages including brood sacs occurred on ovigerous lobsters. No seasonal trends were evident on ovigerous lobsters caught near Grand Manan; prevalence was consistently high (60–93%) and mean intensity ± SE was variable (15 ± 4.0 to 86 ± 63.1). The nemertean developed to maturity on ovigerous lobsters, reproduced on the host egg masses throughout the year, and appeared to produce three generations during a lobster egg incubation period. When lobsters completed egg incubation, nemertean reproduction ceased and some nemerteans either died, left the lobster, or perhaps were shed at molting. Prevalence and mean intensity increased with the size of ovigerous lobsters, and the distribution of nemerteans among ovigerous lobsters was highly aggregated. Ovigerous lobsters infected with >200 nemerteans had extensively damaged egg masses, but were rarely encountered (5 of 291). The impact of P. homari on the egg mortality of wild populations of H. americanus is unknown.

Declining fecundity and factors affecting embryo quality in the American lobster (Homarus americanus) from the Bay of Fundy

2015 ◽  
Vol 72 (3) ◽  
pp. 352-363 ◽  
Author(s):  
Heather N. Koopman ◽  
Andrew J. Westgate ◽  
Zachary A. Siders
Keyword(s):  
Embryo Quality ◽  
Gulf Of Maine ◽  
Energy Content ◽  
Homarus Americanus ◽  
Striking Difference ◽  
Bay Of Fundy ◽  
American Lobster ◽  
Female Size ◽  
Factors Affecting ◽  
Old Females

Recent perturbations in ecosystem and environmental dynamics in the habitat of the American lobster have led to increases in abundance, with unprecedented high landings in some regions. Despite the commercial value of this species, surprisingly little is known about maternal and environmental influences on its reproductive output. We measured fecundity and embryo quality in 1370 ovigerous lobsters from the Bay of Fundy, Canada, during 2008–2013. Female size was generally positively correlated with fecundity (P < 0.001), although some of the very large (and presumably old) females brooded significantly fewer eggs than expected. Egg energy content and lipid content and composition exhibited significant annual differences, indicating environmentally based variation. The most striking difference was a 31% decline in fecundity from 2008 to 2013 (8%–10% per year). We hypothesize that recent warming trends could be responsible for reduced fecundity. Decreased fecundity may be a cause for concern for future recruitment in this population, which has been shown to be an important source of larvae for the Gulf of Maine metapopulation.

Evidence that mud seafloor serves as recruitment habitat for settling and early benthic phase of the American lobster Homarus americanus H. Milne Edwards, 1837 (Decapoda: Astacidea: Nephropidae)

2019 ◽  
Vol 39 (5) ◽  
pp. 594-601
Author(s):  
Kristin M Dinning ◽  
Rémy Rochette
Keyword(s):  
Body Condition ◽  
Relative Abundance ◽  
Size Range ◽  
Homarus Americanus ◽  
Bay Of Fundy ◽  
American Lobster ◽  
Differential Growth ◽  
The Past ◽  
Current Potential ◽  
Important Habitat

Abstract Structurally complex cobble seafloor protects against predators, and is generally assumed to be the only meaningful habitat for settlement and benthic recruitment of American lobsters (Homarus americanus H. Milne Edwards, 1837). Accordingly, historical surveys on featureless substrates such as mud have found few and only older juveniles. Mud, however, is far more common than cobble across the lobster’s range, and may be of increasing importance in regions where the lobster population has been growing over the past few decades. As a first step to determining whether mud seafloor serves as meaningful recruitment habitat for juvenile lobsters, we deployed artificial habitats (bio-collectors) at five locations varying from 100% mud to mostly cobble, in Maces Bay, Bay of Fundy, NB, Canada, to capture young lobsters. A broad size range of lobsters, from new settlers up to adolescents, colonized bio-collectors in all locations, suggesting that lobsters settle and spend at least some of their juvenile life on mud. Differences in body condition (length-standardized mass) of lobsters sampled from the different locations suggest that some individuals must reside on mud for at least months to years, long enough to show differential growth between habitats. The greater relative abundance of adolescents in bio-collectors on mud also suggests their net movement from densely populated cobble beds into mud habitat. We propose that mud seafloor may be a more important habitat for settlement and early survival of American lobsters than is currently appreciated, especially given the current potential saturation of scarce cobble nursery habitat by growing lobster populations and, in some regions, reduced predation on mud seafloor due to overfishing of groundfish.

Reproductive Potential of Three American Lobster (Homarus americanus) Stocks in the Canadian Maritimes

1983 ◽  
Vol 40 (11) ◽  
pp. 1958-1967 ◽  
Author(s):  
A. Campbell ◽  
D. G. Robinson
Keyword(s):  
Nova Scotia ◽  
Egg Production ◽  
Reproductive Potential ◽  
Homarus Americanus ◽  
Curvilinear Relationship ◽  
Bay Of Fundy ◽  
American Lobster ◽  
Female Size ◽  
New Information ◽  
Stock Recruitment

New information on female size at maturity, fecundity, and relative egg production per recruit is presented for American lobsters (Homarus americanus) from three areas in the Canadian Maritimes. Based on pleopod examination, sizes at 50% maturity for females were estimated at 108.1 mm carapace length (CL) from the Fundy area (Bay of Fundy and southwestern Nova Scotia), at 92.5 mm CL from eastern Nova Scotia, and at 78.5 mm CL from Northumberland Strait. There was a curvilinear relationship between the number of eggs per female and CL. An egg-per-recruit model predicted that in all three areas the second and third molt groups beyond the legal minimum recruit size contribute the most to egg production under current exploitation rates. Lobsters in Northumberland Strait and eastern Nova Scotia produce up to 30–50% of their eggs at sizes smaller than those at which females from the Bay of Fundy start to produce eggs. Although the stock–recruitment relationships for H. americanus are unknown, the egg-per-recruit assessment suggests that all three areas would benefit in egg production increases by increasing minimum legal recruit size by one molt increment.

Growth of juvenile American lobster Homarus americanus in a changing environment

2016 ◽  
Vol 557 ◽  
pp. 177-187 ◽  
Author(s):  
MD McMahan ◽  
DF Cowan ◽  
Y Chen ◽  
GD Sherwood ◽  
JH Grabowski
Keyword(s):  
Homarus Americanus ◽  
American Lobster ◽  
Changing Environment
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