scholarly journals A molecular phylogeny of Geotrochus and Trochomorpha species (Gastropoda: Trochomorphidae) in Sabah, Malaysia reveals convergent evolution of shell morphology driven by environmental influences

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10526
Author(s):  
Zi-Yuan Chang ◽  
Thor-Seng Liew
Keyword(s):  
Phylogenetic Signal ◽  
Nuclear Gene ◽  
Shell Morphology ◽  
Annual Precipitation ◽  
High Plasticity ◽  
Shell Size ◽  
Surface Sculpture ◽  
Mount Kinabalu ◽  
Aperture Width ◽  
Shed Light

There are currently eleven Geotrochus and four Trochomorpha species in Sabah. The primary diagnostic character that separates the two genera is the intensity of sculpture on the shell upper surface. All Trochomorpha species have a coarse nodular sculpture while Geotrochus species has a non-nodular sculpture or smooth shell. However, it is known that shell characters are often evolutionary labile with high plasticity in response to environmental factors. Hence, identifying the phylogenetic and ecological determinants for the shell characters will shed light on the shell-based taxonomy. This study aims to estimate the phylogenetic relationship between Geotrochus and Trochomorpha species in Sabah based in two mitochondrial genes (COI, 16S) and one nuclear gene (ITS) and also to examine the influence of temperature, elevation and annual precipitation on the coarseness of shell upper surface sculpture and shell sizes of the species of both genera. Additionally, we also investigated the phylogenetic signal of the shell characters. The phylogenetic analysis showed that Geotrochus and Trochomorpha species are not reciprocally monophyletic. The phylogenetic signal test suggested that shell size and upper surface sculpture are homoplastic, and these shell traits are strongly influenced by elevation and annual precipitation, particularly at the cloud zone of Mount Kinabalu. The highland species of both genera have a coarser shell surface than lowland species. The shell and aperture width decrease with increasing elevation and annual precipitation. In the view of finding above, the current taxonomy of Geotrochus and Trochmorpha in this region and elsewhere that based on shell characters need to be revised with sufficient specimens throughout the distribution range of the two genera.

Ecophenotypic plasticity in shell growth direction of asari clam Ruditapes philippinarum

2021 ◽  
pp. 1-6
Author(s):  
Takeshi Tomiyama
Keyword(s):  
Growth Rate ◽  
Shell Growth ◽  
Shell Height ◽  
Growth Direction ◽  
Ruditapes Philippinarum ◽  
Shell Morphology ◽  
Individual Growth ◽  
Shell Size ◽  
Internal Factors ◽  
Suitable Habitats

Abstract Asari clam (or Manila clam) Ruditapes philippinarum is an important bivalve for local fisheries. This species exhibits a large variation in shell morphology, and the shell roundness tends to be greater in more unsuitable habitats. To test whether the increments in shell size parameters (length, height and width) were affected solely by environmental conditions or by internal factors such as initial shell shapes or growth rate, a field caging experiment was conducted at two different sites of unsuitable and suitable habitats in Matsukawaura Lagoon, Japan, where shell shapes of wild clams were significantly different between the habitats. In the experiment, clams were released from the two sites to the same site or to the other site and were re-collected after 3, 6 and 12 months of caging. Caged clams originating from unsuitable habitats and released to suitable habitats showed a reduction in shell height relative to shell length, while clams from suitable habitats introduced to unsuitable habitats showed marked increases in both shell height and width. Generalized linear mixed models suggested that the increase in shell height was affected largely by the release habitat (environment) whereas the increase in shell width was affected largely by the individual growth rate. These results suggest that marginal growths in shell height and width respond differently to external and internal factors of clams, resulting in plasticity in their shell shapes according to the environments to which they are translocated.

scholarly journals Discordance between Mitochondrial and Nuclear DNA Genes Suggests the Possibility of Hybridization of Indian and Southeast Asian Types of Oecophylla smaragdina (Fabricius) (Hymenoptera, Formicidae) in Bangladesh

2020 ◽  
Author(s):  
M. M. Rahman ◽  
S. Hosoishi ◽  
K. Ogata
Keyword(s):  
Dna Analysis ◽  
Nuclear Dna ◽  
Nuclear Gene ◽  
Southeast Asian ◽  
Phylogenetic Study ◽  
Tropical Islands ◽  
Oecophylla Smaragdina ◽  
Mtdna Sequences ◽  
Mitochondrial Dna Analysis ◽  
Shed Light

Background: Oecophylla smaragdina is distributed from India, SE Asia and Australia including many tropical Islands. A recent phylogenetic study based on mitochondrial DNA analysis reveals that Bangladesh is the overlapping zone of both Indian and Southeast Asian type of O. smaragdina. These two different lineages of Indian and SE Asian type have the opportunities of creating the zone of contacts, but no such data was found. In this study, shed light was given to reveal the chance of hybridized colony of O. smaragdina in Bangladesh. Methods: To asses the hybridization scenario, 28 O. smaragdina colony from 27 localities in Bangladesh were analyzed using Longwave length Rhodopsin (LWRh) nuclear gene sequences and was compared with the mtDNA sequences, which was collected from the same localities and deposited into NCBI GenBank. Results: The inconsistency between mitochondrial and nuclear gene types was observed from two colonies of the overlapped zone of contact. These two colonies were identified as SE Asian type by mtDNA analysis however, by nuclear DNA analysis; it was identified as Indian type. These significant discrepancies within the colony suggested the possibility of hybridization of weaver ant in Bangladesh.

scholarly journals Some Morphological Variations in The Land Snail Monacha cantiana (Montagu,1803) within Baghdad Province

2013 ◽  
Vol 10 (1) ◽  
pp. 1-12
Author(s):  
Baghdad Science Journal
Keyword(s):  
Population Density ◽  
Shell Height ◽  
Calcium Content ◽  
Land Snail ◽  
Shell Morphology ◽  
Shell Size ◽  
Aperture Diameter ◽  
Morphological Variations ◽  
Shell Diameter ◽  
Soil Calcium

The present work includes investigation of some features of shell morphology; shell size, shell thickness, shell colour of the land snail Monacha cantiana, in addition to the correlation between height and diameter of shell and between shell aperture diameter and shell diameter at four sites within Baghdad Province, Iraq. Also, measurements of three environmental variables were made; soil temperature, soil moisture and soil calcium content in adition to population density. Shell Aperture Index (Ia) and Shell Index (SI) for individuals from size class ranged between (9-12)mm were measured. The results showed that the deference in shell size by using (Ia) within population related to temperature, moisture and population density but, the value of Shell Index decreased in AL-Kadhimiya site (0.81-0.97) due to increase in population density. The species was characterized by shell colour variation (creamy white, white ,creamy). Also, The results showed strong and positive correlation between shell height and diameter and between shell aperture diameter and shell diameter for all size classes.

scholarly journals Effect of Magnetized Water Treatment on some Biological Aspects for Fresh Water Snail Lymnaea lagotis (Schrank,1803)

2014 ◽  
Vol 11 (2) ◽  
pp. 975-982
Author(s):  
Baghdad Science Journal
Keyword(s):  
Water Treatment ◽  
Egg Mass ◽  
Shell Size ◽  
Important Species ◽  
Magnetized Water ◽  
Untreated Water ◽  
Fresh Water Snail ◽  
Aperture Width ◽  
Biological Aspects ◽  
River Control

Exposure assays to magnetized water have so far revealed striking results. The present study was conducted to determine the effects of magnetized water treatment with in different intensities 500 , 1000 and 1500 Gauss on some biological aspects for species of freshwater Gastropod Lymnaea lagotis (Schrank, 1803) which important species in faun of aquatic habitats of Iraq. This species are considered a component of the food chain. The obtained results compared with these species which lived in the river(control). Result of these experiments showed increased significance the shell size (shell high, shell aperture length, shell aperture width and shell width) for L. lagotis with increased intensity magnetized water such as treated water with 1000 Gauss intensity compared with untreated water. Although increase significant was observed to fecundity for snails such as (egg mass dimensions, number and diameter of eggs and survival juveniles) with increased intensity of magnetized water comparative with untreated water.

scholarly journals A fixed axis coiling model for the living planktonic foraminifer Globigerinella siphonifera

1992 ◽  
Vol 6 ◽  
pp. 29-29
Author(s):  
Jelle Bijma ◽  
Brian T. Huber ◽  
Christoph Hemleben
Keyword(s):  
Volume Ratio ◽  
Shell Morphology ◽  
Type I ◽  
Type Ii ◽  
Shell Size ◽  
Translation Rate ◽  
Ecological Requirements ◽  
Primary Rule ◽  
Fixed Axis ◽  
Chamber Size

Two morphotypes of Globigerinella siphonifera (Types I and II) can be clearly distinguished in their natural environment based on differences in symbiont distribution, which is dependent on the structure of the pseudopodial network. Laboratory experiments have demonstrated that the life cycle and ecological requirements of Types I and II differ considerably as well. However, qualitative observation of the empty shells reveals no significant differences between these two morphotypes. Therefore, a “fixed-axis” coiling model has been developed to simulate foraminiferal shell morphology with a computer. The model is based on the assumption that isometry is the primary rule implemented in planktonic foraminiferal development. Four parameters (rate of radius increase, number of chambers per whorl, translation rate, and relative distance from the center of any chamber to the coiling axis) and two scaling factors (initial chamber size and number of chambers) suffice to generate geometric models of the shells of these planispirally coiled organisms.Values for the four parameters extracted from digitized SEM microphotographs of dissected specimens of G. siphonifera demonstrate significant differences between the Types I and II. These are primarily due to a different rate of radius increase and a different number of chambers per whorl. Type I has a higher rate, which in combination with its lower number of chambers per whorl results in a more lobate test and a 22% smaller adult shell size than Type II. We suggest that the smaller surface area-to-volume ratio in the Type I population can be explained by increased respiration due to higher oxygen production during symbiotic photosynthesis; TEM has demonstrated that Type II contains twice as many symbionts than Type I and each symbiont contains a higher concentration of chloroplasts.The fixed axis model was also used to describe the ontogeny of G. siphonifera. The model shows that early chambers in log-spirally coiled structures must deviate from a strict isometric arrangement. To maintain exponential growth, the juvenile stage of Types I and II is more planispiral, more umbilicated, and contains more chambers per whorl than the adult stage. Future investigations will focus on the transformation of the shape parameters during later ontogenetic development and during cladogenesis.

scholarly journals Identifying the North American Plum Species Phylogenetic Signal Using Nuclear, Mitochondrial, and Chloroplast DNA Markers

2016 ◽  
Vol 141 (6) ◽  
pp. 623-644 ◽  
Author(s):  
Dario J. Chavez ◽  
Thomas G. Beckman ◽  
José X. Chaparro
Keyword(s):  
Chloroplast Dna ◽  
Prunus Persica ◽  
Phylogenetic Signal ◽  
Phylogenetic Analyses ◽  
Nuclear Gene ◽  
Its Region ◽  
Single Copy ◽  
Species Level ◽  
Species Relationships ◽  
The North

Prunus phylogeny has been extensively studied using chloroplast DNA (cpDNA) sequences. Chloroplast DNA has a slow rate of evolution, which is beneficial to determine species relationships at a deeper level. The chloroplast-based phylogenies have a limitation due to the transfer of this organelle by interspecific hybridization. This creates difficulties when studying species relationships. Interspecific hybrids in Prunus occur naturally and have been reported, which creates a problem when using cpDNA-based phylogenies to determine species relationships. The main goal of this project was to identify nuclear gene regions that could provide an improved phylogenetic signal at the species level in Prunus. A total of 11 species in Prunus and within section Prunocerasus were used. Two peach (Prunus persica) haploids were used to test the reliability of the molecular markers developed in this project to amplify single-copy genes. A total of 33 major genes associated with vernalization response, 16 with tree architecture, and 3 with isozymes, were tested. Similarly, 41 simple sequence repeat (SSR) markers, seven cpDNA regions, and the internal transcribed spacer (ITS) region, were used. Multiple gene regions were identified and provided the greatest number of characters, greatest variability, and improved phylogenetic signal at the species level in Prunus section Prunocerasus. Out of those, trnH-psbA, PGI, MAX4, AXR1, LFY, PHYE, and VRN1 are recommended for a phylogenetic analysis with a larger number of taxa. The use of potentially informative characters (PICS) as a measure of how informative a region will be for phylogenetic analyses has been previously reported beneficial in cpDNA regions and it clearly was important in this research. This will allow selecting the region(s), which can be used in phylogenetic studies with higher number of taxa.

The effects of salinity on the density, shell size and survival of a mangrove gastropod: laboratory and field evidence

2015 ◽  
Vol 96 (6) ◽  
pp. 1191-1199
Author(s):  
Rafaela Camargo Maia ◽  
Ricardo Coutinho
Keyword(s):  
Population Density ◽  
Temporal Distribution ◽  
Shell Morphology ◽  
Eastern Coast ◽  
Ecological Indicator ◽  
Mangrove Forests ◽  
Shell Size ◽  
The North ◽  
Field Evidence ◽  
Melampus Coffeus

The macro-detritivore gastropod Melampus coffeus plays an important role in energy transfer in neotropical mangroves and, because it consumes tree leaves, it may be a potential ecological indicator of degraded mangrove areas. The objective of this study was to analyse the spatial-temporal distribution and population dynamics parameters of M. coffeus in mangroves and correlate environmental variables with population density, shell morphology and survival. Samples were collected monthly in two mangrove forests with different salinities, located on the north-eastern coast of Brazil. Height, width and aperture height of the animals’ shell were measured. The effects of salinity on population density and size distribution in M. coffeus were evaluated in field and laboratory experiments. The results showed that populations of M. coffeus present low density and are composed of large individuals during the dry season in both mangrove forests. These populations are denser and show predominance of small individuals during the rainy season when salinity decreases. The results obtained in the experiments confirm the observations in the field. Animals at extreme sizes (small and large) subjected to different salinity treatments over a moderate period showed higher mortality rates than individuals of intermediate size.

Phylogenetic relationships in Lasiocampidae (Lepidoptera): Initial evidence from elongation factor-1α sequences

2000 ◽  
Vol 31 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Charles Mitter ◽  
Timothy P. Friedlander ◽  
Jerome C. Regier ◽  
Richard S. Peigler
Keyword(s):  
Phylogenetic Signal ◽  
Cladistic Analysis ◽  
Elongation Factor ◽  
Nuclear Gene ◽  
Sister Group ◽  
Bootstrap Support ◽  
Elongation Factor 1Α ◽  
Factor I ◽  
Protein Encoding ◽  
Synonymous Change

AbstractNo explicit higher-level cladistic analysis exists for Lasiocampidae, the largest family of Bombycoidea (s. lat.). As a start toward such a phylogeny, we sequenced the protein-encoding, nuclear gene elongation factor-I α (EF-1α) from 13 lasiocampids representing all the subfamilies and tribes present in North America, plus three outgroups. Phylogenetic signal, mainly from synonymous change, was strong, with seven of 11 potential groups in Lasiocampidae showing > 90% bootstrap support under parsimony and likelihood analyses. Separation between the two American subfamilies, Lasiocampinae and Macromphaliinae, was strongly supported. Within the largest tribe, Lasiocampini, EF-1α strongly resolves a clade of unusually large lasiocampids, containing a New World element ((Eutachyptera, Gloveria), (Prorifrons, Quadrina)) with a Eurasian sister group of Macrothylacia + Dendrolimus. Resolution of deeper relationships within Lasiocampinae, however, including those among tribes, is presently weak and will probably require expanded taxon sampling. The 'large Lasiocampini' group shares a possibly synapomorphic life cycle (not expressed in its tropical members) that includes overwintering by larvae. Larval sociality is found in three of the 'large Lasiocampini' genera, each of which may represent an origin separate from the others and from Malacosoma.

scholarly journals The shell morphology of the latest Cretaceous (Maastrichtian) trionychid turtle Helopanoplia distincta

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4169 ◽  
Author(s):  
Walter G. Joyce ◽  
Tyler R. Lyson
Keyword(s):  
Phylogenetic Analysis ◽  
North Dakota ◽  
Late Cretaceous ◽  
Type Specimen ◽  
Shell Morphology ◽  
Surface Sculpture ◽  
Fine Grained ◽  
Hell Creek Formation ◽  
The Past ◽  
Metaplastic Bone

Background Helopanoplia distincta is an extinct soft-shelled turtle (Pan-Trionychidae) for which the type specimen is a fragmentary costal and the inguinal notch portion of the left hypoplastron from the Late Cretaceous (Maastrichtian) Lance Formation of Wyoming, USA that bear a distinct surface sculpture pattern consisting of raised tubercles. Over the course of the past few decades, a number of additional, fragmentary specimens from the Late Cretaceous (Maastrichtian) Hell Creek Formation of Montana and North Dakota have been referred to this taxon based on the presence of these tubercles, but a more complete understanding of the anatomy and phylogenetic relationships of this distinctive soft-shelled turtle is still outstanding. Methods We here figure and describe shell remains of eight fossils referable to Helopanoplia distincta from the Hell Creek Formation of Montana and North Dakota that, in combination, document nearly all aspects of the shell morphology of this taxon. We furthermore explore the relationships of this fossil turtle by inserting it into a modified phylogenetic analysis of pan-trionychid relationships. Results The new fossil material thoroughly supports the validity of Helopanoplia distincta. In addition to its unique surface sculpture pattern, this turtle can be diagnosed relative to all other named pan-trionychids by the presence of a distinct corner along the margin of costals II, the complete covering of costal ribs I–VI by metaplastic bone, midline contact of the main plastral elements, hyoplastral shoulder, presence of a lateral, upturned margin on the hyo/hypoplastron that is covered dorsally and laterally by sculptured metaplastic bone, a single, lateral hyoplastral process, and the apomorphic presence of fine scallops along the margin of costals VIII, formation of a laterally embraced, rounded nuchal, anteriorly rounded costals I, distally expanded costals II, and narrow costals VII. A phylogenetic analysis places Helopanoplia distincta as sister to the clade formed by Plastomenus thomasii and Hutchemys spp., thereby confirming its identity as a plastomenid. The vast majority of Helopanoplia distincta material has been recovered from fine-grained overbank deposits, thereby supporting the hypothesis that this turtle favored ponded waters.

A MONTE CARLO STUDY OF THE EXCHANGE BIAS EFFECTS IN MAGNETIC NANOPARTICLES WITH FERROMAGNETIC CORE/ANTIFERROMAGNETIC SHELL MORPHOLOGY

2007 ◽  
Vol 21 (18) ◽  
pp. 1169-1177 ◽  
Author(s):  
E. EFTAXIAS ◽  
M. VASILAKAKI ◽  
K. N. TROHIDOU
Keyword(s):  
Monte Carlo ◽  
Magnetic Nanoparticles ◽  
Exchange Bias ◽  
Monte Carlo Study ◽  
Bias Field ◽  
Shell Morphology ◽  
Shell Size ◽  
Monte Carlo Simulation Technique ◽  
Exchange Bias Field ◽  
Experimental Findings

We have used the Monte Carlo simulation technique to investigate the mechanism that gives the exchange bias effects on composite magnetic nanoparticles with Ferromagnetic (FM) core/Antiferromagnetic (AFM) shell morphology. Our study shows that:. (a) the exchange bias field depends mainly on the structure of the interface and less on its size,. (b) when the shell size becomes bigger than the core size the exchange bias field decreases,. (c) the size of the vertical shift depends on the total number of uncompensated spins in the nanoparticle and. (d) the training effect has its origin to the rearrangement of the spins at the FM/AFM interface. Our results are in good agreement with experimental findings.

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