Discordant patterns of morphological and genetic divergence in the 'Austrocochlea constricta' (Gastropoda: Trochidae) species complex

1996 ◽  
Vol 47 (8) ◽  
pp. 981 ◽  
Author(s):  
KE Parsons
Keyword(s):  
Genetic Divergence ◽  
Species Complex ◽  
Morphological Traits ◽  
Morphological Characters ◽  
Genetic Distances ◽  
Allele Frequencies ◽  
Morphological Divergence ◽  
Enzyme Loci ◽  
Spatial Isolation ◽  
Western Australian

Patterns of genetic and morphological divergence were examined among Western Australian (Abrolhos Islands and Albany) and Tasmanian members of the highly variable 'Austrocochlea constricta' species complex. Analyses of allele frequencies at 13 enzyme loci confirmed the presence of three species within this complex in Tasmania, revealing additional diagnostic differences not previously detected. Where combinations of species sympatry were examined in Tasmania, seven diagnostic loci separated A. constricta and A. brevis, four separated A. porcata and A. brevis, and one separated A. porcata and A. constricta. Western Australian animals were genetically most similar to Tasmanian A. constricta populations, separated from them by genetic distances of just 0.018 (Albany) to 0.107 (Abrolhos), despite spatial isolation over ~3000 km. These genetic distances, in addition to that separating Abrolhos and Albany populations (0.138), are considered within the range possible for allopatric conspecifics. In comparison, genetic distances separating A. constricta from sympatric A. porcata (0.191) and A. brevis (0.803) in Tasmania were much larger. However, on the basis of a range of morphological traits, which were species-diagnostic in Tasmania, Abrolhos animals most closely resembled A. porcata, and Albany animals appeared intermediate to A. porcata and A. constricta. This suggests Australia-wide discordance among genetic and morphological characters of the 'A. constricta' complex.

Recharacterisation and photo-documentation of five North American Bursaphelenchus species from C.L. Massey’s type material

Nematology ◽  
2016 ◽  
Vol 18 (3) ◽  
pp. 311-336 ◽  
Author(s):  
Natsumi Kanzaki ◽  
Robin M. Giblin-Davis ◽  
Barbara J. Center
Keyword(s):  
Species Complex ◽  
Morphological Traits ◽  
Morphological Characters ◽  
Female Characters ◽  
Species Status ◽  
Type Specimens ◽  
Lateral Field ◽  
Female Tail ◽  
Photo Documentation ◽  
The Status

The type specimens of fiveBursaphelenchusspecies described by Massey,i.e.,B. bestiolus,B. corneolus,B. elytrus,B. newmexicanusandB. wilfordi, were re-examined and photo-documented to update their descriptions in light of a contemporary understanding of the genus. The presence of a lateral field, basal swelling of stylet, P1 ventral single papilla of males and a pair of three-celled structures in females, which were not described or mentioned in the original descriptions, were observed, although the number of lateral incisures were not clarified because of sample condition. Within these five species, the intrageneric groupings ofB. bestiolusandB. wilfordihad been unclear. In the present study, because of newly observed morphological characters,B. bestiolusis considered to belong to thehofmanni-group, and is close toB. talonusandB. rufipennis. These three species form a species complex and are distinguished from each other only by female tail morphology. The species status ofB. wilfordiis still unclear, although, based on spicule morphology and structure and arrangement of genital papillae, we consider it to belong to thehofmanni-group, close toB. parvispicularis,B. paraparvispicularisandB. osumiana. However, female characters ofB. wilfordiare also similar to members of thecocophilus-group andParasitaphelenchus. Re-isolation and molecular identification are necessary to confirm the status of these species. By contrast, the affiliations ofB. corneoluswith thehofmanni-group andB. elytrusandB. newmexicanuswith theeggersi-group were confirmed. Based upon its morphological traits,B. corneolusis close toB. gerberaeandB. paracorneolus, and is distinguished from these species by its spicule morphology, female tail morphology and female post-uterine sac length. However, male specimens ofB. corneoluswere not available for the present study and confirmation is necessary.Bursaphelenchus elytrusis similar toB. tusciaeand is distinguished from it by its spicule (condylus) morphology and excretory pore position.Bursaphelenchus newmexicanusis close toB. glochisand is distinguished from it mostly by morphometrics and spicule (condylus) morphology. However, morphometrics usually vary among individuals and populations of a species, necessitating morphometric and molecular comparisons of more isolates (strains) in order to clarify specific status.

DNA Barcoding of Simulium asakoae (Diptera: Simuliidae) From Northern Thailand

2020 ◽  
Vol 57 (5) ◽  
pp. 1675-1678 ◽  
Author(s):  
Van Lun Low ◽  
Wichai Srisuka ◽  
Atiporn Saeung ◽  
Tiong Kai Tan ◽  
Zubaidah Ya’cob ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Dna Barcoding ◽  
Genetic Divergence ◽  
Species Complex ◽  
Morphological Variability ◽  
Single Species ◽  
Genetic Distances ◽  
Morphological Identification ◽  
Dna Barcodes ◽  
Barcode Gap

Abstract Previous studies suggested the presence of species complex in the so-called Simulium asakoae Takaoka & Davies (Diptera: Simuliidae) in Thailand due to its high morphological variability and genetic divergence. To investigate whether the true S. asakoae is present in Thailand, we performed a detailed morphological identification of S. asakoae and compared its DNA barcodes with the morphospecies S. asakoae from Myanmar and the typical S. asakoae from Malaysia. Phylogenetic analysis revealed the Thai materials analyzed in this study were indeed genetically similar with those from Myanmar and Malaysia, though genetic distances 0–2.27% were observed. We tentatively regard this divergence as intraspecific variation, and the automatic barcode gap discovery analysis further supports them as a single species.

scholarly journals The spatio-temporal axis for phenotypic change: a comparison of source and translocated Arctic charr populations after 25 generations

2020 ◽  
Author(s):  
Marius H. Hassve ◽  
Mari Hagenlund ◽  
Kjartan Østbye ◽  
Katja Häkli ◽  
Thomas Vogler ◽  
...  
Keyword(s):  
Genetic Divergence ◽  
Morphological Traits ◽  
Management Practices ◽  
Arctic Charr ◽  
Phenotypic Change ◽  
Source Population ◽  
Morphological Divergence ◽  
Genetic Structuring ◽  
Trait Divergence ◽  
Morphological Differences

AbstractEvolution of morphological traits is hypothesized to act on an extended time scale, yet studies have suggested that these changes are possible within a few generations. Trophic polymorphism enabled through niche adaptations and ecological opportunity is one phenomenon that facilitate occurrence of rapid adaptive variation, common in many northern freshwater fish species. One such species is Arctic charr, which is known for its extensive variation in morphology and the occurrence of morphs. However, the speed at which such morphological variation arises is poorly studied despite the importance for understanding the onset of evolution. The aim of this study was to elucidate this process in a gradient of eight lakes that was stocked with Arctic charr in the period from 1910 to 1917 from Lake Tinnsjøen, Norway. We used morphological measurements to test for differences in traits between populations and Haldane and Darwin’s evolutionary rates to estimate divergence rates in traits. We also tested for correlation between putative genetic and morphological divergence. In addition, we contrasted the morphological divergence with that expected under neutral genetic expectations, using 12 microsatellite markers, to analyze whether and which morphological differences that is following early genetic divergence. A significant genetic differentiation was found between the source population and five of the translocated populations with corresponding differences in morphological traits for four of the populations. Population genetic structuring indicated six different genetic clusters. The translocated populations also exhibited trait divergence estimated with both Haldane and Darwin’s rates. Differences in morphological traits showed a significant correlation with genetic divergence, and the morphological differences were most likely affected by differences in lake parameters such as maximum depth, lake size and fish community. We conclude that intraspecific morphological and genetic divergence can form on short evolutionary time scales with important implications for conservation and management practices.

scholarly journals Genetic Diversity In Mango (Mangifera Indica L.) Through Multivariate Analysis

2013 ◽  
Vol 38 (2) ◽  
pp. 343-353 ◽  
Author(s):  
DAN Majumder ◽  
L Hassan ◽  
MA Rahim ◽  
MA Kabir
Keyword(s):  
Genetic Divergence ◽  
Mangifera Indica ◽  
Principal Component ◽  
Morphological Characters ◽  
Genetic Distances ◽  
Fruit Weight ◽  
Eigen Values ◽  
Cluster Distance ◽  
Clustering Pattern ◽  
Single Cluster

The genetic divergence was assessed in 60 mango genotypes through D2- statistics and principal component analysis. The genotypes under study were grouped into eight clusters and the diversity was influenced by the morphological characters, not by the geographical distribution of the genotypes. The clustering pattern revealed that the genotypes collected from the same region did not fall in the single cluster. The maximum inter cluster distance was noticed between cluster II and cluster VIII, and the lowest between clusters VII and cluster VIII. From the cluster means, cluster I was high yielding and ranked first in terms of number of secondary branches per inflorescence, percent fruit set per inflorescence, and yield per plant. Cluster VIII had only one genotype which produced the highest percentage of flowering shoots, % perfect flowers, number of fruits per plant, and %TSS. The genotypes of cluster VII produced the biggest sized fruits. The first nine characters of the principal component axes with eigen values above unity accounted for 88.3% of the total variation among the fifteen characters. Weight of harvested fruits per plant (0.990 and 0.181), number of fruits per plant (0.101 and 0.607) and individual fruit weight (0.027 and 0.107) for both the vectors were positive across two axes indicating the important components of genetic divergence. The genotypes belonging to clusters I, VII and VIII with high to moderate genetic distances might be recommended for use in crossing programs to produce new recombinants with desired traits. Bangladesh J. Agril. Res. 38(2): 343-353, June 2013 DOI: http://dx.doi.org/10.3329/bjar.v38i2.15895

scholarly journals New Species and New Records of Sponge-Inhabiting Barnacles (Cirripedia, Balanidae, Acastinae) from Australia

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 290
Author(s):  
Andrew M. Hosie ◽  
Jane Fromont ◽  
Kylie Munyard ◽  
Diana S. Jones
Keyword(s):  
New Species ◽  
New Records ◽  
Morphological Characters ◽  
Genetic Distances ◽  
Similar Species ◽  
Diverse Group ◽  
Undescribed Species

The subfamily Acastinae contains a diverse group of barnacles that are obligate symbionts of sponges and alcyonacean and antipatharian corals. Integrating morphological and genetic (COI) data to compare against known species, this paper reports on nine species of sponge-inhabiting barnacles of the subfamily Acastinae, including three undescribed species (Acasta caveata sp. nov., Euacasta acutaflava sp. nov., and E. excoriatrix sp. nov.) and three species previously not recorded in Australian waters (A. sandwichi, Pectinoacasta cancellorum, and P. sculpturata). The new species are distinguished from similar species by a suite of morphological characters as well as genetic distances. A lectotype for Pectinoacasta cancellorum is designated. Sponge hosts were identified for all specimens where possible and are represented by 19 species from eight families and five orders.

scholarly journals Relationship Between Root and Yield Related Morphological Characters in Pea (Pisum Sativum L.)

2014 ◽  
Vol 66 (1) ◽  
pp. 3-15
Author(s):  
Sylwia Ciaglo-Androsiuk
Keyword(s):  
Root System ◽  
Morphological Traits ◽  
Lateral Roots ◽  
Morphological Characters ◽  
Yield Potential ◽  
Cultivated Plants ◽  
Genetic Determination ◽  
Canonical Correlations ◽  
Effect On Yield

AbstractRelation between morphological traits of the root system and yield related traits is an important issue concerning efforts aiming at improving of ideotype of cultivated plants species, including pea. In this paper, to analyse the dependency between traits describing the root system morphology and yield potential, Person’s andSpearman's_correlations as well as canonical correlations were used.Root system was analyzed in 14 and 21 day-old seedlings growing in blotting-paper cylinders. Yield potential of pea was analysed in a field experiment. Results of Person’s and Spearman's_correlations revealed that number of lateral roots and lateral roots density were correlated witch yield related traits. Correlation between root length and shoot length was observed only for 14 day-old seedlings. The result of canonical correlations revealed that number of lateral roots and lateral roots density had the largest effect on yield related traits. This work highlights, that in order to improve the yield of pea it might become necessary to understand genetic determination of morphological traits of the root system, especially number of lateral roots.

Biochemical Systematics, Biogeography and Evolutionary Rates in Species of the Mediterranean Genus Tyrrhenoleuctra (Plecoptera, Leuctridae)

2004 ◽  
Vol 35 (3) ◽  
pp. 299-306 ◽  
Author(s):  
◽  
J. M. Tierno de Figueroa ◽  
◽  
◽  
Keyword(s):  
North Africa ◽  
Evolutionary Rate ◽  
Taxonomic Status ◽  
Morphological Characters ◽  
Genetic Distances ◽  
Western Mediterranean ◽  
Similar Distribution ◽  
Undescribed Species ◽  
Vicariance Event ◽  
Definition Of

AbstractThe western Mediterranean stonefly genus Tyrrhenoleuctra traditionally includes 3 species: T. minuta (Spain, North Africa, Balearic Islands), T. tangerina (Spain, North Africa), T. zavattarii (Corsica and Sardinia). Since the traditional morphological characters display great and overlapping variation, allozyme electrophoresis was used to clarify taxonomic and phylogenetic relationships within the genus and to discuss biogeographical implications. The results clearly discriminate at least four entities: the Corso-Sardinian unit, for which the name T. zavattarii can be used; the Balearic population, representing an undescribed species; at least two Iberian peninsular species. However, more data on topotypic populations are needed to define the taxonomic status of the Iberian species (including definition of the currently used names T. minuta and T. tangerina). The presence of Tyrrhenoleuctra in Sardinia and Corsica is likely due to an old vicariance event following separation of the Sardinia-Corsica microplate from the Iberian Peninsula. Calibration of the molecular clock (genetic distances vs. Corso-Sardinian plate split from Iberia) resulted in a very low evolutionary rate (0.008 D/my), lower than those found in taxonomically distant groups (including stoneflies) with similar distribution.

scholarly journals Null expectation of spatial correlograms under a stochastic process of genetic divergence with small sample sizes

2000 ◽  
Vol 23 (4) ◽  
pp. 739-743 ◽  
Author(s):  
Mariana Pires de Campos Telles ◽  
José Alexandre Felizola Diniz-Filho
Keyword(s):  
Stochastic Process ◽  
Genetic Divergence ◽  
Isolation By Distance ◽  
Genetic Distances ◽  
Small Sample ◽  
Group Method ◽  
Gene Frequencies ◽  
Exponential Relationship ◽  
Local Populations ◽  
Pair Group

An Ornstein-Uhlenbeck process was used to simulate the exponential relationship between genetic divergence and geographic distances, as predicted by stochastic processes of population differentiation, such as isolation-by-distance, stepping-stone or coalescence models. These simulations were based only on the spatial coordinates of the local populations that defined a spatial unweighted pair-group method using arithmetic averages (UPGMA) link among them. The simulated gene frequency surfaces were then analyzed using spatial autocorrelation procedures and Nei's genetic distances, constructed with different numbers of variables (gene frequencies). Stochastic divergence in space produced strong spatial patterns at univariate and mutivariate levels. Using a relatively small number of local populations, the correlogram profiles varied considerably, with Manhattan distances greater than those defined by other simulation studies. This method allows one to establish a range of correlogram profiles under the same stochastic process of spatial divergence, thereby avoiding the use of unnecessary explanations of genetic divergence based on other microevolutionary processes.

New circumscription of Cryptanthus and new Cryptanthoid genera and subgenera  (Bromeliaceae: Bromelioideae) based on neglected morphological traits and molecular phylogeny

Phytotaxa ◽  
2017 ◽  
Vol 318 (1) ◽  
pp. 1 ◽  
Author(s):  
ELTON M. C. LEME ◽  
SASCHA HELLER ◽  
GEORG ZIZKA ◽  
HEIDEMARIE HALBRITTER
Keyword(s):  
Type Species ◽  
Morphological Traits ◽  
Fruit Size ◽  
Morphological Characters ◽  
Morphological Evidence ◽  
New Genera ◽  
Sex Distribution ◽  
Stigma Morphology ◽  
Leaf Succulence ◽  
Petal Size

The authors provide a new circumscription for genera of the “Cryptanthoid complex” of Bromeliaceae subfam. Bromelioideae, originally composed of Cryptanthus, Lapanthus, Orthophytum, and Sincoraea, on the basis of new or re-evaluated ecological, geographical and morphological evidence, as well as molecular phylogenies. A new generic status is proposed for Cryptanthus subg. Hoplocryptanthus and two new genera, Forzzaea, and Rokautskyia, as well as four new subgenera in Orthophytum (Capixabanthus, Clavanthus, Krenakanthus, and Orthocryptanthus) are described to render taxonomic units monophyletic. The recognized taxa are well circumscribed by the combination of geographical range, ecology and morphological characters (sex distribution, leaf succulence, sepal and petal size and connation, petal appendages, pollen and stigma morphology, fruit size, calyx persistency, seed size and number per fruit). Field collected living specimens of 78 of the 81 species of Cryptanthus s.l., all species of Lapanthus, 58 of the 59 species of Orthophytum, and all species of Sincoraea were analysed in habitat and/or in cultivation, allowing the documentation and illustration of new and underutilized characters. The molecular analysis incorporated 91 accessions representing 33 species of Cryptanthus, all species (3) of Lapanthus, 42 species of Orthophytum, and 9 species of Sincoraea, including the type species for the first three genera and four outgroup taxa. The results suggest, that some morphological characters generally considered homoplasious for Bromelioideae, for the “Cryptanthoid complex”, are not homoplasious at least within the obtained, biogeographycally well delimited clades and their taxonomical utility is redeemed.

scholarly journals The effect of the height gradient on morphological traits of Dracocephalum nutans L.

2021 ◽  
Vol 38 ◽  
pp. 00024
Author(s):  
Gulnora Denisova ◽  
Safarbek Rahimov
Keyword(s):  
Morphological Traits ◽  
Leaf Blade ◽  
Morphological Characters ◽  
Altitude Gradient ◽  
Blade Length ◽  
Wide Range ◽  
Inflorescence Length ◽  
Height Factor

Individuals of Dracocephalum nutans L. have been studied at different altitude levels from 460 to 2437 m above the level seas. The influence of the height gradient on morphological characters has been shown: the number of generative and vegetative shoots, the height of the generative shoot, the length and width of the leaf blade, length of its petiole, and inflorescence length. It was found that the height gradient has the greatest influence on the height of the generative shoot and the length of the inflorescence. When individuals grow higher along the altitude gradient, the height of the generative shoot and the length of the inflorescence decrease. The fluctuation of the average values of the traits of D. nutans in a wide range was established. The intrapopulation analysis of D. nutans individuals does not depend on the height factor.

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