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Φυλογενετικές σχέσεις των αμφιβίων ομάδων ισοπόδων με τα υπόλοιπα ισόποδαΚούτμος, Θεόδωρος 05 February 2008 (has links)
Τα ισόποδα αποτελούν τη μοναδική τάξη οργανισμών ανάμεσα σε όλα τα Καρκινοειδή που πέτυχε να εποικήσει όλους τους τύπους ενδιαιτημάτων, από τα βάθη των ωκεανών μέχρι τα βουνά, τις έρημους και τις τροπικές περιοχές. Παρόλα αυτά, οι φυλογενετικές σχέσεις εντός της τάξης των ισοπόδων παραμένουν σε πολλά σημεία ασαφείς. Η οικογένεια Tylidae, που περιλαμβάνει 27 αμφίβια είδη, ανήκει σύμφωνα με τη σημερινή συστηματική κατάταξη στην υπόταξη Oniscidea, τη μοναδική που περιλαμβάνει αντιπροσώπους με χερσαίο ή ημι-χερσαίο τύπο διαβίωσης. Αν και υπάρχουν αμφιβολίες ως προς τη μονοφυλετική προέλευση αρκετών από τις 9 υποτάξεις που περιλαμβάνουν θαλάσσιους αντιπροσώπους, η προέλευση των Oniscidea θεωρείται αδιαμφισβήτητα μονοφυλετική. Εντούτοις, δεν υπάρχει ακόμη συμφωνία ως προς την ακριβή τοποθέτηση του κλάδου των Tylidae στο φυλογενετικό δέντρο των Oniscidea.
Ο βασικός στόχος της παρούσας εργασίας ήταν ο προσδιορισμός των φυλογενετικών σχέσεων των αμφιβίων ισοπόδων της οικογένειας Tylidae με τα υπόλοιπα ισόποδα, με έμφαση στις σχέσεις με τα υπόλοιπα Oniscidea. Για το σκοπό αυτό χρησιμοποιήθηκαν μοριακοί δείκτες από 14 γένη ισοπόδων, τα οποία αντιπροσωπεύουν όλους τους τύπους διαβίωσης, από τον αποκλειστικά θαλάσσιο έως τον αποκλειστικά χερσαίο. Η πειραματική προσέγγιση περιλάμβανε τον πολλαπλασιασμό αλληλουχιών του πυρηνικού γονίδιου 18s rDNA και των μιτοχονδριακών 16s rDNA και COI με τη μέθοδο της αλυσιδωτής αντίδρασης πολυμέρασης (PCR), τον προσδιορισμό της αλληλουχίας τους και τη φυλογενετική ανάλυσή τους με μεθόδους μέγιστης φειδωλότητας, μέγιστης πιθανοφάνειας και μπεϊεσιανής συμπερασματολογίας.
Οι μιτοχονδριακές αλληλουχίες εμφανίζουν πολύ υψηλά ποσοστά νουκλεοτιδικών υποκαταστάσεων, και σε συνδυασμό με τη χαμηλή αξιοπιστία των δέντρων που παράγονται φαίνεται πως έχουν απωλέσει εντελώς το φυλογενετικό τους σήμα. Η αλληλουχία του 18s rDNA έχει μήκος 2400-3400 bp και αποτελείται από 4 συντηρημένες περιοχές και 3 υπερ-μεταβλητές. Για τις φυλογενετικές αναλύσεις χρησιμοποιήθηκαν μόνο οι συντηρημένες περιοχές, που συνιστούν ένα σύνολο 1597 διακριτών χαρακτήρων. Στα αποτελέσματα από όλες τις υπολογιστικές μεθόδους η οικογένεια Tylidae τοποθετείται στο τελικό δέντρο σε αδελφό κλάδο του τάξου Crinochaeta της υπόταξης Oniscidea. Εντούτοις, παρατηρήθηκε πως η οικογένεια Ligiidae τοποθετείται σε κλάδο μη-συγγενικό προς τα υπόλοιπα χερσαία ισόποδα, υπονοώντας πως η υπόταξη Oniscidea δεν είναι μονοφυλετική. Για να ελέγξουμε αυτήν την υπόθεση, χωρίσαμε τα δεδομένα μας σε αλληλουχίες από θαλάσσιους και σε αλληλουχίες από χερσαίους αντιπροσώπους, πραγματοποιώντας ένα σύνολο από πρόσθετες αναλύσεις. Από τα αποτελέσματα φαίνεται πως η υπόταξη Oniscidea είναι μονοφυλετική και η αντίθετη αρχική υπόθεση οφείλεται σε ‘θόρυβο’ στο φυλογενετικό σήμα των συντηρητικών περιοχών του 18s rDNA. Τέλος, από τις πρόσθετες αναλύσεις προκύπτουν, με ισχυρή στατιστική στήριξη, φυλογενετικά δέντρα που υποστηρίζουν τη συστηματική κατάταξη που είχε προτείνει ο Erhard από τις μορφολογικές του μελέτες, τοποθετώντας τα Tylidae εντός του τάξου ‘Holoverticata’. / Isopods comprise a unique order among the Crustaceans that has settled effectively all possible habitats on the planet. The phylogenetic relationships, though, between the 10 suborders remain unresolved, as many of them might prove to be non-monophyletic taxa. The family Tylidae consists of 27 amphibian species and is traditionally classified in the suborder Oniscidea, which includes all the terrestrial and semi-terrestrial isopods and that is thought to be unambiguously monophyletic. However, the previous phylogenetic studies have proposed many hypotheses concerning the relations between the Tylidae and the other Oniscidea, lacking any plausible consensus.
In order to resolve those phylogenetic relations, we used two mitochondrial sequences (16s, COI) and one nuclear (18s) from 14 genera of isopods. Our experimental approach included PCR amplification, sequencing and computational phylogenetic analyses by means of maximum parsimony, maximum likelihood and Bayesian inference.
The mitochondrial sequences present extreme values of nucleotide substitutions and evident saturation, a fact that prohibits their use in further analyses. The 18s sequences vary significantly in size (2400-3400 bp) and consist of 4 conserved and 3 hyper-variable regions. Only the conserved regions were used for analysis, resulting to a dataset of 1597 discrete nucleotide characters. Regardless of the method used, the family Tylidae appeared as a sister-clade of the taxon Crinochaeta (suborder Oniscidea) in the cladograms. We noticed, though, that the taxon Diplochaeta (Oniscidea: Ligiidae) appeared (with low bootstrap values) in a distant clade of all the other Oniscidea, a result that does not support the monophyletic origin of the Oniscidea. In order to test the validity of this result, we splitted our dataset and conducted additional, separate analyses for the sequences of the marine isopods and those of the terrestrial isopods. Our results indicate that the suborder Oniscidea is monophyletic, so the initial opposite hypothesis was due to weak phylogenetic signal. Finally, our cladograms support, with significant confidence, the systematic classification that Erhard (1998) had proposed through his studies on morphological characters of the Oniscidea, placing together the family Tylidae and the taxon Crinochaeta under the name ‘Holoverticata’.
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Φυλογεωγραφία των ενδημικών ειδών του γένους Trachelipus (Isopoda, Oniscidea) στην ΕλλάδαΚαμηλάρη, Μαρία 08 July 2011 (has links)
Το γένος Trachelipus περιλαμβάνει οργανισμούς σχετικά στενόοικους οι
οποίοι ζουν είτε στην παρόχθια βλάστηση ρεμάτων και ποταμών είτε σε υγρά δάση.
Στη χώρα μας έχουν καταγραφεί 8 από τα 50 είδη του γένους, 4 από τα οποία είναι
ενδημικά της Ελλάδας. Το ένα από αυτά εξαπλώνεται από την Κρήτη μέχρι την
Ήπειρο, ένα στα νησιά του κεντρικού Αιγαίου, ένα στην Κρήτη και ένα στο νότιο
Ευβοϊκό. Η κατανομή κάθε είδους είναι ασυνεχής, είτε λόγω γεωγραφικών
(νησιωτικοί πληθυσμοί κλπ) είτε λόγω ενδιαιτηματικών παραγόντων. Η διάκριση
μεταξύ των ειδών έχει γίνει βάσει περιορισμένου αριθμού μορφολογικών
χαρακτήρων και δεν είναι βέβαιο ότι αντανακλά τις πραγματικές φυλογενετικές
σχέσεις τους. Από τα αποτελέσματα προηγούμενης μελέτης διαπιστώθηκε έντονη
απόκλιση μεταξύ των προτύπων της γενετικής ποικιλότητας και εκείνης της
τρέχουσας ταξινόμησης σε ορισμένες ομάδες πληθυσμών του γένους αυτού.
Επιπλέον, φάνηκε σημαντικός βαθμός γενετικής απομόνωσης μεταξύ των
πληθυσμών ενός είδους, ενισχύοντας την άποψη περί ισχυρής μεταπληθυσμιακής
συγκρότησής τους.
Στην παρούσα μελέτη, συλλέχθηκαν 47 πληθυσμοί στην ηπειρωτική Ελλάδα,
οι οποίοι στη μεγάλη τους πλειοψηφία ανήκαν στο είδος Trachelipus kytherensis
(σύμφωνα με την ισχύουσα ταξινόμηση). Σε αυτούς προστέθηκαν και τα δεδομένα
των Parmakelis et al 2008 (16 πληθυσμοί) έτσι ώστε να είναι πιο ολοκληρωμένη η
μελέτη και η εξαγωγή συμπερασμάτων για το γένος Trachelipus. Συνολικά μελετήθηκαν γενετικά 63 πληθυσμοί του γένους, χρησιμοποιώντας
ως μοριακούς δείκτες τα μιτοχονδριακά γονίδια 16S rRNA και COI. Έπειτα από
απομόνωση του DNA και τον πολλαπλασιασμό των συγκεκριμένων τμημάτων με PCR
προσδιορίστηκε η αλληλουχία των βάσεων, και υπολογίστηκε η γενετική
διαφοροποίηση εντός και μεταξύ των πληθυσμών. Για την ανάλυση των
φυλογενετικών σχέσεων μεταξύ των πληθυσμών ή/και των ειδών χρησιμοποιήθηκαν
οι μέθοδοι της Σύνδεσης Γειτόνων (Neighbor Joining-NJ), της Μέγιστης
Φειδωλότητας (Maximum Parsimony-MP) και της Μπεϊεσιανής Συμπερασματολογίας
(Bayesian Inference-BI). Το τελικό μήκος των αλληλουχιών μετά την επεξεργασία
ήταν 386 θέσεις για το γενετικό τόπο 16S rRNA και 512 θέσεις για το γενετικό
τόπο COI. Με τα δεδομένα αυτά δεδομένα πραγματοποιήθηκε τόσο ανεξάρτητη όσο
και συνδυασμένη ανάλυση.
Από τα αποτελέσματα φαίνονται πληθυσμοί οι οποίοι παρα το ότι είναι πολύ
κοντινοί γεωγραφικά, και μέχρι σήμερα θεωρείται πως ανήκουν στο ίδιο είδος
(Trachelipus kytherensis), εμφανίζουν μεγάλες γενετικές αποστάσεις μεταξύ τους
και ομαδοποιούνται σε διαφορετικούς και αρκετά απομακρυσμένους κλάδους των
δένδρων σε όλες τις αναλύσεις (NJ, MP, BI). Η τοπολογία των κλάδων, καθώς και
η απουσία σαφούς γεωγραφικού προτύπου στην ομαδοποίηση των πληθυσμών του T.
kytherensis, καταδεικνύει ότι πιθανότατα δεν έχουμε να κάνουμε με ένα μόνο είδος,
αλλά με περισσότερα που είναι δύσκολο να διακριθούν μορφολογικά, τουλάχιστον με
τους μέχρι σήμερα χρησιμοποιούμενους ταξινομικούς διαγνωστικούς χαρακτήρες.
Αυτό ενισχύεται και από τις γενετικές αποστάσεις που καταγράφηκαν στην παρούσα
μελέτη και εμφανίζονται ιδιαίτερα αυξημένες (μέγιστες παρατηρηθείσες γενετικές
απόστασεις: 27,3% COI, 17,6% 16S rRNA) ακόμα και σε σχέση με αυτές που έχουν
αναφερθεί σε άλλες έρευνες για τη διάκριση ειδών ισοπόδων.
Επισημαίνεται η ιδιαίτερα μεγάλη γενετική διαφοροποίηση μεταξύ των
αντιπροσώπων του γένους. Επιπλέον καταδεικνύεται πως η Πελοπόννησος
φιλοξενεί τα είδη Trachelipus ‘kytherensis’ και T. aegaeus (τουλάχιστον στη χερσόνησο της Αργολίδας) αλλά και πιθανόν μια τρίτη μορφή στα βόρεια (νέο είδος;)
η οποία εμφανίζεται ευρύτερα στην ηπειρωτική Ελλάδα. Θα είχε ιδιαίτερο
ενδιαφέρον λοιπόν να μελετηθούν αυτές οι πιθανές «ζώνες επαφής» ως προς τη
γονιδιακή τους ροή, ώστε να εκτιμηθεί το ποσοστό απομόνωσης των πληθυσμών και,
κατ’ επέκταση, του κάθε είδους. / The phylogenetic relationships among terrestrial isopod species are still
largely unknown because robust analyses have started to appear only relatively
recently. Species-level taxonomy has been based mainly on a few secondary
sexual characters of males, although recent analyses based on molecular
markers have indicated that species definitions based on morphology may
underestimate the true levels of divergence among populations. Furthermore,
within several genera or species groups, morphological characters do not provide
clear-cut taxonomic resolution, so that many changes in the interpretation of
nominal species have appeared in the literature.
The genus Trachelipus comprises of relatively stenoecious animals living in
habitats generally threatened by human activities, such as humid forest sites
and riparian habitats. It includes some 50 species distributed around the
Palaearctic, with 8 species recorded from Greece, 4 endemic to the country. The
distribution of species is discontinuous due to the increasing fragmentation of
its habitats and the expansion of agricultural land and dry woodland. Projected
climatic change will restrict further gene flow between Trachelipus populations,
as dry habitats are expected to expand in Greece. Species–level taxonomy has
been based on a few morphological characters, mainly the secondary sexual
characters of males, exhibiting significant variation, and is controversial. Very
high intraspecific genetic divergence among several populations has been
documented. In this study we attempt a phylogeographic analysis among the Greek
endemic species of the genus. We sampled 47 populations from several sites in
mainland Greece. In our analyses we incorporated data from previous work (16
populations) in order to better estimate possible geographic structure in the
patterns of divergence among populations, and to throw new light in the
systematics of the species. Overall, 63 populations were considered. After total
DNA extraction, we sequenced the two PCR amplified mtDNA gene fragments,
namely 16S rRNA and cytochrome oxidase subunit I (COI), and calculated the
genetic divergence within and among the populations studied, as well as their
phylogenetic relationships. The methods for phylogenetic reconstruction used
were Neighbor Joining (NJ), Maximum Parsimony (MP) and Bayesian Inference
(BI) for each mtDNA sequence data and the concatenated dataset.
The phylogenetic trees obtained from the molecular data – from all three
phylogenetic methods (NJ, MP, BI) - produced trees with quite congruent
topologies. Some populations that are considered conspecific exhibit large
genetic distances and cluster in different clades. The highly-structured
phylogenetic tree and the lack of an overall geographic pattern in the clustering
of Trachelipus populations indicates that very probably we are not dealing with a
single species, but rather with a number of cryptic species, hardly distinguished
by means of currently used morphological characters. This is further
corroborated by the genetic distances separating the clades hosting nominal T.
kytherensis populations (max_dCOI=27.3% and max_d16S rRNA=17.6%).
In general, it can be argued that the genetic distances recorded in the
present study are quite large compared with those reported for different
species and even genera in other studies of terrestrial isopods. Furthermore, it
is evident than there are two species present in the Peloponnese, i.e. Trachelipus
‘kytherensis’ and T. aegaeus (in Argolis peninsula). In northern Peloponnese, a
third form is also present (new species?) that occurs throughout the central and northern part of mainland Greece. These ‘contact zones’ should be further
investigated in terms of genetic flow and isolation of the populations and/or
species.
Both the phylogeny presented here and the genetic distances separating
populations appear to justify the necessity of further investigation into the
phylogeny of the Greek Trachelipus species using a population by population
approach. It is likely that morphology inadequately describes real variation
inside and among species; hence, diagnoses based on the morphological
characters used so far for the delineation of Trachelipus species should be
reconsidered under the light of more extensive molecular phylogenetic analyses.
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História natural de Benthana cairensis (Isopoda: Oniscidea)Sokolowicz, Carolina Coelho January 2010 (has links)
A subordem Oniscidea abriga os isópodos terrestres, os quais apresentam uma grande riqueza de espécies em diferentes ambientes com características completamente diversas, desde a zona litorânea até ambientes desérticos. No Brasil há uma diversidade de espécies ainda pouco estudada, sendo que a família Philosciidae representa uma grande parte da fauna de isópodos da América do Sul. O presente estudo tem como objetivos descrever uma nova espécie no gênero Benthana para o estado do Rio Grande do Sul, descrever seus estágios de manca e juvenil, assim como caracterizar sua estrutura populacional com respeito aos aspectos reprodutivos e crescimento. Benthana cairensis foi descrita como uma nova espécie de Philosciidae e tem como caracteres diagnósticos a presença de 17 estetascos na antênula, exópodo do pleópodo 1 do macho alongado apresentando um lobo na margem lateral interna. Essa espécie é semelhante a três outras do gênero em relação a presença do lobo, no entanto diferencia-se de todas elas devido às diferenças no número de omatídeos, inserção dos ramos do urópodo e dimorfismo sexual nos pereiópodos dos machos. A fase imatura e indiferenciada sexualmente apresenta três estágios, chamados de mancas. O estágio de Manca I é caracterizado pela simplicidade de suas estruturas e pela sua rápida duração, de aproximadamente 4 horas; apresenta 6 pares de pereiópodos, esses ainda glabros e o aparelho bucal fracamente desenvolvido ainda sem a presença dos dentes pectinados na maxilula, característicos de Benthana. O estágio seguinte, de Manca II, já apresenta o aparelho bucal mais desenvolvido com os dentes pectinados da maxilula e pereiópodos já com o padrão de setas semelhante ao adulto, inclusive a seta “hand-like” do carpo 1, uma autapomorfia do gênero. O último estágio de manca (Manca III) caracteriza-se pela presença do sétimo par de pereiópodos presente dobrado ventralmente sob o corpo do animal. Os estágios de juvenis caracterizam-se pela diferenciação sexual, mas ainda são imaturos sexualmente. Os três primeiros estágios foram descritos para os machos com destaque para o desenvolvimento da protusão do exópodo do pleópodo 1, outra autapomorfia do gênero, o qual só começa a ficar evidente no segundo estágio (JUII) e somente apresenta-se completamente desenvolvido quando o animal atinge aproximadamente 1.0 mm de largura de cefalotórax (LC). O dimorfismo sexual presente nos quatro primeiros pares de pereiópodos dos machos começa a aparecer após os três primeiros estágios de juvenil e está completamente evidente em machos de aproximadamente 1.2 mm de LC. A população de Benthana cairensis do Sítio Cairé caracteriza-se por apresentar uma reprodução contínua durante o ano. As fêmeas investem menos em uma única prole, no entanto são capazes de se reproduzir mais de uma vez ao longo de sua vida. A proporção sexual operacional da população é de 1:1, mostrando que há um equilíbrio no que se refere ao número de machos e fêmeas aptos para reprodução. Os machos vivem menos que as fêmeas e são menores. As fêmeas possuem o corpo maior, o que aumenta a superfície para abrigar a prole o que foi demonstrado pela correlação positiva do tamanho da fêmea com o número de ovos. As características de desenvolvimento de B. cairensis são semelhantes a outras espécies de Philosciidae, apresentando três estágios de mancas. Suas características populacionais, no que se referem a estação reprodutiva e investimento reprodutivo, são semelhantes a outras espécies subtropicais e, como esperado, diferentes de espécies de isópodos que vivem em regiões temperadas. / Terrestrial isopods are included in the suborder Oniscidea which shows a great species richness living at different places showing diverse environmental conditions, occurring from the littoral zone through desert regions. In Brazil there is a diversity that is still poorly studied in which the family Philosciidae represents a great part of South America’s woodlice fauna. The present study aims to describe a new species of the genus Benthana to the state of Rio Grande do Sul, to describe its manca and juvenile stages as well as to characterize its population structure concerning reproductive aspects and growth. Benthana cairensis was described as a new species of Philosciidae and presents the following diagnostic characters: 17 aesthetascs on the antennula and male pleopod 1 exopod elongated with a lobe on the inner lateral margin. This species resembles other three species of the genus concerning the presence of pleopod lobe; however it is differentiated by the number of omatidia, insertion of uropod endopod and exopod and sexual dimorphism on male’s pereiopods. The immature and undifferentiated phase has three stages, called mancas. The Manca I is marked by the simplicity of its appendages and by its queek duration, of about 4 hours; it presents 6 pairs of pereiopods still glabrous and mouth parts weekly developed still without the presence of the pectinate teeth of maxillula, characteristic of Benthana. The next stage, Manca II, already shows the mouth parts a little more complete, presenting the pectinate teeth of maxillula and the pereiopods showing the setae pattern of the adult, including the hand-like seta on carpus 1, an autapomorphy of the genus. The last manca stage (Manca III) is characterized by the presence of the 7th pair of pereiopods folded ventrally on the pereion. The juvenile stages are sexually differentiated, but still immature. The first three stages were described for males, enphatizing the development of dentiform protusion of pleopod exopod 1, another autapomorphy of the genus which begins to be evident only at the second stage (JUII) and it is completely formed when the animal reaches 1.0 mm of cephalothorax width (CW). Sexual dimorphism at the first four male pereiopods beggins to develop after the three juvenile stages and it is completely formed on males of approximatly 1.2 mm of CW. The population of Benthana cairensis at Sítio Cairé is characterized by showing a continnuous reproduction during the year. Females invest less in a single brood, but are able to reproduce more than once in its lifetime. The operational sex ratio of population is 1:1, which shows that there is an equillibrium concerning the number of males and females that are able to reproduce. Males live less than females and are smaller. Females have a bigger body which increases the surface where the brood develops; this was demonstrated by the positive correlation of female body size with the offspring number. The developmental characteristics of B. cairensis are similar to those of the other species of Philosciidae presenting three manca stages. Its population features concerning reproductive season and reproductive effort resembles those of other subtropical species and as expected, is different from species that occur at temperate regions.
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História natural de Benthana cairensis (Isopoda: Oniscidea)Sokolowicz, Carolina Coelho January 2010 (has links)
A subordem Oniscidea abriga os isópodos terrestres, os quais apresentam uma grande riqueza de espécies em diferentes ambientes com características completamente diversas, desde a zona litorânea até ambientes desérticos. No Brasil há uma diversidade de espécies ainda pouco estudada, sendo que a família Philosciidae representa uma grande parte da fauna de isópodos da América do Sul. O presente estudo tem como objetivos descrever uma nova espécie no gênero Benthana para o estado do Rio Grande do Sul, descrever seus estágios de manca e juvenil, assim como caracterizar sua estrutura populacional com respeito aos aspectos reprodutivos e crescimento. Benthana cairensis foi descrita como uma nova espécie de Philosciidae e tem como caracteres diagnósticos a presença de 17 estetascos na antênula, exópodo do pleópodo 1 do macho alongado apresentando um lobo na margem lateral interna. Essa espécie é semelhante a três outras do gênero em relação a presença do lobo, no entanto diferencia-se de todas elas devido às diferenças no número de omatídeos, inserção dos ramos do urópodo e dimorfismo sexual nos pereiópodos dos machos. A fase imatura e indiferenciada sexualmente apresenta três estágios, chamados de mancas. O estágio de Manca I é caracterizado pela simplicidade de suas estruturas e pela sua rápida duração, de aproximadamente 4 horas; apresenta 6 pares de pereiópodos, esses ainda glabros e o aparelho bucal fracamente desenvolvido ainda sem a presença dos dentes pectinados na maxilula, característicos de Benthana. O estágio seguinte, de Manca II, já apresenta o aparelho bucal mais desenvolvido com os dentes pectinados da maxilula e pereiópodos já com o padrão de setas semelhante ao adulto, inclusive a seta “hand-like” do carpo 1, uma autapomorfia do gênero. O último estágio de manca (Manca III) caracteriza-se pela presença do sétimo par de pereiópodos presente dobrado ventralmente sob o corpo do animal. Os estágios de juvenis caracterizam-se pela diferenciação sexual, mas ainda são imaturos sexualmente. Os três primeiros estágios foram descritos para os machos com destaque para o desenvolvimento da protusão do exópodo do pleópodo 1, outra autapomorfia do gênero, o qual só começa a ficar evidente no segundo estágio (JUII) e somente apresenta-se completamente desenvolvido quando o animal atinge aproximadamente 1.0 mm de largura de cefalotórax (LC). O dimorfismo sexual presente nos quatro primeiros pares de pereiópodos dos machos começa a aparecer após os três primeiros estágios de juvenil e está completamente evidente em machos de aproximadamente 1.2 mm de LC. A população de Benthana cairensis do Sítio Cairé caracteriza-se por apresentar uma reprodução contínua durante o ano. As fêmeas investem menos em uma única prole, no entanto são capazes de se reproduzir mais de uma vez ao longo de sua vida. A proporção sexual operacional da população é de 1:1, mostrando que há um equilíbrio no que se refere ao número de machos e fêmeas aptos para reprodução. Os machos vivem menos que as fêmeas e são menores. As fêmeas possuem o corpo maior, o que aumenta a superfície para abrigar a prole o que foi demonstrado pela correlação positiva do tamanho da fêmea com o número de ovos. As características de desenvolvimento de B. cairensis são semelhantes a outras espécies de Philosciidae, apresentando três estágios de mancas. Suas características populacionais, no que se referem a estação reprodutiva e investimento reprodutivo, são semelhantes a outras espécies subtropicais e, como esperado, diferentes de espécies de isópodos que vivem em regiões temperadas. / Terrestrial isopods are included in the suborder Oniscidea which shows a great species richness living at different places showing diverse environmental conditions, occurring from the littoral zone through desert regions. In Brazil there is a diversity that is still poorly studied in which the family Philosciidae represents a great part of South America’s woodlice fauna. The present study aims to describe a new species of the genus Benthana to the state of Rio Grande do Sul, to describe its manca and juvenile stages as well as to characterize its population structure concerning reproductive aspects and growth. Benthana cairensis was described as a new species of Philosciidae and presents the following diagnostic characters: 17 aesthetascs on the antennula and male pleopod 1 exopod elongated with a lobe on the inner lateral margin. This species resembles other three species of the genus concerning the presence of pleopod lobe; however it is differentiated by the number of omatidia, insertion of uropod endopod and exopod and sexual dimorphism on male’s pereiopods. The immature and undifferentiated phase has three stages, called mancas. The Manca I is marked by the simplicity of its appendages and by its queek duration, of about 4 hours; it presents 6 pairs of pereiopods still glabrous and mouth parts weekly developed still without the presence of the pectinate teeth of maxillula, characteristic of Benthana. The next stage, Manca II, already shows the mouth parts a little more complete, presenting the pectinate teeth of maxillula and the pereiopods showing the setae pattern of the adult, including the hand-like seta on carpus 1, an autapomorphy of the genus. The last manca stage (Manca III) is characterized by the presence of the 7th pair of pereiopods folded ventrally on the pereion. The juvenile stages are sexually differentiated, but still immature. The first three stages were described for males, enphatizing the development of dentiform protusion of pleopod exopod 1, another autapomorphy of the genus which begins to be evident only at the second stage (JUII) and it is completely formed when the animal reaches 1.0 mm of cephalothorax width (CW). Sexual dimorphism at the first four male pereiopods beggins to develop after the three juvenile stages and it is completely formed on males of approximatly 1.2 mm of CW. The population of Benthana cairensis at Sítio Cairé is characterized by showing a continnuous reproduction during the year. Females invest less in a single brood, but are able to reproduce more than once in its lifetime. The operational sex ratio of population is 1:1, which shows that there is an equillibrium concerning the number of males and females that are able to reproduce. Males live less than females and are smaller. Females have a bigger body which increases the surface where the brood develops; this was demonstrated by the positive correlation of female body size with the offspring number. The developmental characteristics of B. cairensis are similar to those of the other species of Philosciidae presenting three manca stages. Its population features concerning reproductive season and reproductive effort resembles those of other subtropical species and as expected, is different from species that occur at temperate regions.
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Life history and reproductive ecology of an intertidal isopod Dynoides dentisinus (Crustacea: Peracarida: Isopoda) / 岩礁潮間帯性甲殻類シリケンウミセミ (軟甲綱:フクロエビ上目:等脚目) の生活史と繁殖生態Nakamachi, Takeru 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21605号 / 理博第4512号 / 新制||理||1647(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 朝倉 彰, 准教授 下村 通誉, 教授 中務 真人 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
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Možnosti užití Chilopoda, Diplopoda a Isopoda: Oniscidea k bioindikaci relativně trvalých ekologických podmínek smrkových a bukových ekosystémů Moravskoslezských BeskydLazorík, Martin January 2016 (has links)
In forest management, forest typology is often used in long term planning. Its basic is forest site, which represents a relatively permanent biocoenosis with phytocoenological similarities. The basis of knowledge is synusia undergrowth (plant components), accompanied by ecological (habitat) characteristics. To changes in the development of ecological factors in the ecosystem is sensitive animal ingredients, than plants. Therefore, the long term effort of knowledge bioindicative animal ingredients, which reacts faster than the flora on induced changes in the ecosystem. In the network of 38 localities covering 12 forest site complex, occurrence of millipede, centipede and terrestrial isopoda was investigated (a method of pitfall traps, 16,189 ex., 39 species). In order to speciy of environmental characteristics, data from 30 weather stations were used, detailed pedological ressearch including soil chemistry and phytocoenological research were carried out. Obtained data were processed by MNDS, PCA and CCA analyses. The most significant factor were coverage by herbaceous vegetation and contents of Ca, and Mg in soil. Distribution of the individual species in relation to different forest site complexes was determined by CCA analysis. All three studied groups of species, i.e. millipedes, centipedes and terrestrial isopods, were evaluated as significant for bioindication within the forest ecosystems. Centipedes and millipedes enabled us to associate each FSC with a specific species. Terrestrial isopods indicated well the localities with high groundwater level and the process of peat formation. Due to the strict requirements indicator pros'tredí was using the methods set value Indicator type Lithobius nodulipes on a forest site complex 5L (Montane AshAlder) and Lithobius pelidnus to 5Y (Skeletal Fir Beech) bioinikator. Also important position had the second Hyloniscu riparius and Ligidium hypnorum 6 O/R (Nutrient medium Peat Spruce).
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Suchozemští stejnonožci jako modeloví půdotvorní činitelé v praktické školní výuce / Terrestrial Isopods as Model Soil-forming Agents in Practical School EducationKorbélyi, Tereza January 2018 (has links)
- 2 - Abstract Woodlice (Isopoda) belong to major soil decompositors of plant material and at the same time easily collectible. These organisms are therefore suitable for integration into practical school lessons. The aim of this thesis is therefore to design inquiry-based education using Isopoda as an example of soil decompositors. The first part of this thesis is focused on the theoretical introduction to inquiry- based education. It is also devoted to describe woodlice (Isopoda), explain their morphology, life cycle and cover the most common species of Isopoda occurring in the Czech Republic. A simplified determination key for these most common species is included. The second part of the thesis includes complete instructions on how to use these organisms in practical teaching with elements of inquiry-based education. The manual contains techniques for collecting and storing woodlice. The manual also contains instructions to individual experiments, including the list of needed tools and advice, where to obtain the tools and other didactic materials. The third part of the thesis has a research character, where, based on a questionnaire survey, students' attitudes towards woodlice (Isopoda) and their knowledge shift before and after the practical lesson are evaluated. Keywords Isopoda, inquiry-based...
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Aspects of the ecology and biology of the isopod, Exosphaeroma hylocoetes, (Barnard, 1940) in three temporarily open/closed southern African estuariesHenninger, Tony Oskar January 2009 (has links)
Temporarily open/closed estuaries (TOCE’s) are the numerically dominant type of estuary accounting for ≈ 70 % of all estuaries along the South African coastline. Despite their numerical dominance, aspects of the biology of organisms within these systems, particularly macrocrustacea remain poorly understood. This study firstly assessed the abundance and biomass of the most common isopod, Exosphaeroma hylocoetes, in three Eastern Cape TOCE’s, (the West Kleinemonde, East Kleinemonde and Kasouga Estuaries), and their response to mouth breaching events. This study was followed by aspects of the biology of the isopod including their utilisation of submerged macrophytes as a refuge from predation and/or possible food source, as well as the growth rates of the isopods in the laboratory under different environmental conditions. Mean isopod abundances and biomasses ranged between 0 and 4 791 ind. m⁻² and 0 and 9.65 mg dwt. m⁻² in the West Kleinemonde Estuary and between 0 and 108 ind. m⁻² and 0 and 0.318 mg dwt. m⁻² in the nearby East Kleinemonde Estuary. In the Kasouga Estuary, the values ranged between 0 and 3 650 ind. m⁻² and 0 and 5.105 mg dwt. m⁻². Temporal and spatial changes in the abundance and biomass of E. hylocoetes within the three systems was primarily linked to mouth phase, with populations declining when the mouth was open and to a lesser extent, seasonality. In all three estuaries maximum isopod abundances and biomasses were recorded in their middle and upper reaches, which could be ascribed to the presence of submerged macrophytes particularly Ruppia maritima, in two of the estuaries. Males (5.71 ± 0.41 mm) were significantly larger than females (3.99 ± 0.26 mm), but the sex ratios were skewed in favour of females, (a common feature in many isopod populations). Females were found carrying brood throughout the study, releasing offspring directly into the water column, to allow recruitment to the populations. The larger the female, the larger the brood carried (up to a maximum of 72 embryo/mancas). Results of laboratory experiments indicate that the close association of Exosphaeroma hylocoetes with submerged macrophytes is a result of the plant stands providing a refuge against predation by selected ichthyofauna. However stable carbon isotope and fatty acid analyses indicate that E. hylocoetes made use of ephiphytic algae and detritus on the stems of R. maritima, rather than the submerged macrophyte itself. There were no significant differences in the growth rates of male and female isopods at combinations of temperature (15 and 25 °C) and salinity (15 and 35 ‰). Laboratory growth studies revealed that males lived longer than females (25.77 ± 3.40 weeks vs 21.52 ± 3.00 weeks), and therefore achieved larger overall size. Females, however, reached sexual maturity (at 2.5 mm) at a faster rate (two to four weeks) than males (5.5 mm after 6.5 to 11 weeks), dependent on temperature. Exosphaeroma hylocoetes with its association with submerged macrophytes, early maturity, its growth rates and longevity, female-biased sex ratios and year-round breeding, all contribute to its success in temporary open/closed estuaries.
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