Search

At least five different reproductive modes were reported in the neotropical frog genus Leptodactylus, all of them involving the building of foam nests. We analyzed the early ontogeny of five species of the L. fuscus group building terrestrial chambers where eggs are deposited, and of two species of the L. latrans group constructing a floating nest over the surface of lentic waters. The ontogenetic period described herein includes the occurrence of exclusively embryonic structures and the initial stages of development of larval features. In a likely relation to ecological aspects of oviposition and developmental mode, embryos of these two groups differ in several features. Embryos of the L. fuscus group were mainly pigmentless, were large sized with an extensive yolk provision, showed a dorsal kyphosis and lacked adhesive glands. Conversely, embryos of the L. latrans group were darkly pigmented, lacked a dorsal curvature, were comparatively smaller and less yolked, and showed adhesive glands in a peculiar type D morphogenetic pattern. Embryos of the L. latrans group had long, profusely branched, highly ciliated external gills, which were arranged ventrally. The comparative analysis of developmental sequences revealed an early emergence of hind limbs in Leptodactylus species relative to a reference leiuperine trajectory, an earlier differentiation of external gills in the species of the L. fuscus group, and an overall earlier development of mouthparts in embryos of the L. latrans group. Further analyses in a phylogenetic context are needed to evaluate the ancestral reconstructions of the development sequence and detect evolutionary relevant heterochronies in the genus. Fil: Grosso, Jimena Renee. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina Fil: Baldo, Juan Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentina Fil: Vera Candioti, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina

Horned Frogs of the family Ceratophryidae are conspicuous anurans represented bythree endemic South American genera. Most ceratophryids inhabit semiaridenvironments, but three species of Ceratophrys occupy tropical or temperate humid areas.Several morphological and behavioral characters of larvae and adults are conserved across the family. Based on examination of specimens and accounts in the literature, the embryonic development of C. ornata, C. cranwelli, and the monotypic genus Chacophrys are described and compared with that of species of Lepidobatrachus. Ceratophryid embryos share a suite of morphological features and heterochronic shifts during development. Most features, such as gill structure, ciliation, early hatching, and precocious differentiation of the gut and hind limbs, are shared by all the species regardless the differences in the habitats that occupy. This is consistent with previous observations of some adult characters, and likely supports the hypothesis of an early diversification of ceratophryids in semiarid environments. Other embryonic features, such as the morphology and ontogeny of the oral disc and digestive tract, are correlated with larval feeding habits and vary within the family. The evolutionary and ecological significance of some conserved characters (e.g., gastrulation pattern, Type-A adhesive glands) and other taxon-specific features (e.g., nasal appendix) remain to be explored in the group. Fil: Grosso, Jimena Renee. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina Fil: Baldo, Juan Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentina Fil: Salgado Costa, Carolina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Natale, Guillermo Sebastian. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Vera Candioti, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina

Background Self-powered flight is one of the most energy-intensive types of locomotion found in vertebrates. It is also associated with a range of extreme morpho-physiological adaptations that evolved independently in three different vertebrate groups. Considering that development acts as a bridge between the genotype and phenotype on which selection acts, studying the ossification of the postcranium can potentially illuminate our understanding of bat flight evolution. However, the ontogenetic basis of vertebrate flight remains largely understudied. Advances in quantitative analysis of sequence heterochrony and morphogenetic growth have created novel approaches to study the developmental basis of diversification and the evolvability of skeletal morphogenesis. Assessing the presence of ontogenetic disparity, integration and modularity from an evolutionary approach allows assessing whether flight may have resulted in evolutionary differences in the magnitude and mode of development in bats. Results We quantitatively compared the prenatal ossification of the postcranium (24 bones) between bats (14 species), non-volant mammals (11 species) and birds (14 species), combining for the first time prenatal sequence heterochrony and developmental growth data. Sequence heterochrony was found across groups, showing that bat postcranial development shares patterns found in other flying vertebrates but also those in non-volant mammals. In bats, modularity was found as an axial-appendicular partition, resembling a mammalian pattern of developmental modularity and suggesting flight did not repattern prenatal postcranial covariance in bats. Conclusions Combining prenatal data from 14 bat species, this study represents the most comprehensive quantitative analysis of chiropteran ossification to date. Heterochrony between the wing and leg in bats could reflect functional needs of the newborn, rather than ecological aspects of the adult. Bats share similarities with birds in the development of structures involved in flight (i.e. handwing and sternum), suggesting that flight altriciality and early ossification of pedal phalanges and sternum are common across flying vertebrates. These results indicate that the developmental modularity found in bats facilitates intramodular phenotypic diversification of the skeleton. Integration and disparity increased across developmental time in bats. We also found a delay in the ossification of highly adaptable and evolvable regions (e.g. handwing and sternum) that are directly associated with flight performance. Electronic supplementary material The online version of this article (10.1186/s12862-019-1396-1) contains supplementary material, which is available to authorized users.

Integracija, modularnost i razvojna ograničenja predstavljaju važne komponente fenotipske varijabilnosti. U ovoj tezi analiziran je uticaj ovih komponenti na morfološku evoluciju ekstremiteta pet vrsta velikih krestatih mrmoljaka. Veliki krestasti mrmoljci predstavljaju važne model organizme za istraživanja u oblasti morfološke integracije i razvojnih ograničenja, posebno ako se analiziraju ekstremiteti. To je grupa blisko srodnih vrsta sa poznatim filogenetskim odnosima, i izraženom vezom izmedju morfološke forme/tipa (oblika tela i dužine ekstremiteta) i preference prema akvatičnoj/terestričnoj sredini. Akvatične vrste se odlikuju izduženim telom i kratkim nogama, dok su vrste sa više terestričnim životnim stilom snažnije i robusnije građe sa dugim nogama. Takođe, kao grupa sa složenim životnim ciklusom, gde larveni, juvenilni i adultni stupanj imaju različite morfologije, ekološke sredine i preference, načine ishrane i lokomocije, veliki krestasti mrmoljci imaju posebno mesto u izučavanju ontogenetskih putanja tokom razvića. Ontogenetska promena niše i tranzicija između akvatične i terestrične sredine je povezana sa procesom metamorfoze. Iako ekstremiteti mrmoljaka ne prolaze kroz drastične promene strukture tokom tog procesa, funkcionalni zahtevi za efikasnom lokomocijom u te dve sredine su bitno različiti. Pretpostavka je da razlike između vrsta u pogledu stepena korišćenja akvatične tj. terestrične lokomocije, može biti faktor koji doprinosi razlikama u dužinama skeletnih elemenata i različitim obrascima korelacija između elemenata ekstremiteta, oslikavajući adaptacije na različite uslove sredine i način života (više ili manje akvatičan-terestričan)... Integration, modularity and developmental constraints are three related components of phenotypic variability. Their impacts on morphological evolution on limbs in five species of crested newts were analyzed in this thesis. Crested newts are valuable model or ganisms in studies of morphological integration and developmental constraints, especially when concern limbs. They are closely related group of species with known phylogenetic relations, and each characterized by a specific body-to-limb conformation associated with their respective ecologies. Aquatic species of newts have small, elongate bodies and small limbs while more terrestrial species are with large, stocky bodies and robust limbs. Also, as group with complex life cycle, where larval, juvenile and adult stage have different morphologies, ecol ogies and different diet and locomotor preferences, crested newts have special pl ace in studies of changes in ontogenetic trajectories. Ontogenetic niche change and transition between aquatic and terrestrial environment is connected with process of metamorphosis. Although limbs in newts do not undergo drastic chan ges in structure during that process, functional demands for high efficient loco motion in both environments are quit different. It is assumed that the differenc es between species in degree of aquatic and terrestrial locomotion may be the fa ctor which can attribute to changes in length of skeletal elements and differe nt patterns of correlations between limb elements, reflecting adaptations on diffe rent environments and life styles of analyzed species of crested newts...

Integracija, modularnost i razvojna ograničenja predstavljaju važne komponente fenotipske varijabilnosti. U ovoj tezi analiziran je uticaj ovih komponenti na morfološku evoluciju ekstremiteta pet vrsta velikih krestatih mrmoljaka. Veliki krestasti mrmoljci predstavljaju važne model organizme za istraživanja u oblasti morfološke integracije i razvojnih ograničenja, posebno ako se analiziraju ekstremiteti. To je grupa blisko srodnih vrsta sa poznatim filogenetskim odnosima, i izraženom vezom izmedju morfološke forme/tipa (oblika tela i dužine ekstremiteta) i preference prema akvatičnoj/terestričnoj sredini. Akvatične vrste se odlikuju izduženim telom i kratkim nogama, dok su vrste sa više terestričnim životnim stilom snažnije i robusnije građe sa dugim nogama. Takođe, kao grupa sa složenim životnim ciklusom, gde larveni, juvenilni i adultni stupanj imaju različite morfologije, ekološke sredine i preference, načine ishrane i lokomocije, veliki krestasti mrmoljci imaju posebno mesto u izučavanju ontogenetskih putanja tokom razvića. Ontogenetska promena niše i tranzicija između akvatične i terestrične sredine je povezana sa procesom metamorfoze. Iako ekstremiteti mrmoljaka ne prolaze kroz drastične promene strukture tokom tog procesa, funkcionalni zahtevi za efikasnom lokomocijom u te dve sredine su bitno različiti. Pretpostavka je da razlike između vrsta u pogledu stepena korišćenja akvatične tj. terestrične lokomocije, može biti faktor koji doprinosi razlikama u dužinama skeletnih elemenata i različitim obrascima korelacija između elemenata ekstremiteta, oslikavajući adaptacije na različite uslove sredine i način života (više ili manje akvatičan-terestričan). Analiza morfološke integracije i modularnosti je utvrdila postojanje dva važna aspekta variranja elemenata ekstremiteta velikih krestastih mrmoljaka. Odgovarajući ontogenetski stupnjevi su sličniji između vrsta nego sukcesivni ontogenetski stupnjevi u okviru jedne iste vrste, sa najvećim nivoom integracije u juvenilnom stupnju. Visoki nivo integracije prisutan u juvenilnom stupnju predstavlja funkciju brzog, koordinisanog rasta skeleta ekstremiteta tokom perioda u okviru koga sistemski hormoni imaju odlučujuću ulogu, dok je niska ukupna integracija na adultnom stupnju je najverovatnije rezultat mnogih lokalnih i globalnih-sistemskih faktora koji menjaju jedan drugome efekat u vremenu i prostoru, pri čemu bifazični životni ciklus sa različitim načinima lokomocije, imaju odlučujuću ulogu u ontogenetskim promenama morfološke integracije i modularnosti. Razlike u obrascima integracije između više akvatičnih i više terestričnih vrsta mrmoljaka su predstavljene nižim stepenom korelacija između homologih elemenata ekstremiteta, i povećanjem korelacija između elemenata unutar ekstremiteta kod terestričnih vrsta velikih mrmoljaka (kao T. karelinii), dok više akvatične vrste (kao T. dobrogicus) imaju suprotan obrazac variranja sa većim korelacijama između homologih elemenata ekstremiteta nego između elemenata unutar ekstremiteta. Ova studija je pokazala važan uticaj razvojnih ograničenja u kreiranju morfološke varijabilnosti ekstremiteta velikih krestastih mrmoljaka. Uporedna analiza osifikacionih sekvenci ekstremiteta utvrdila je postojanje nekoliko sinapomorfnih heterohroničnih promena kod velikih krestastih mrmoljaka, koje uključuju kašnjenje u sekvenci drugog prsta i ubrzanje metakarpalnog elementa III i metatarzalnog elementa V. Ove heterohronične promene nisu adaptivne ali su važne za razmatranje morfološke evolucije ekstremiteta kod velikih krestastih mrmoljaka jer uključuju promenu preaksijalne ka postaksijalnoj dominaciji u razvojnoj sekvenci, koja nije poznata kod repatih vodozemaca. Analiza alometrijskih obrazaca variranja ekstremiteta velikih mrmoljaka je pokazala dva važna rezultata: osobenosti obrazaca rasta kod vrste T. dobrogicus, kao i zajednički obrazac rasta nakon završene metamorfoze kod svih vrsta velikih mrmoljaka. Ovi rezultati ukazuju na verovatni uticaj i ulogu kako prirodne selekcije, tako i unutrašnjih-razvojnih mehanizama koji regulišu variranje dužine ekstremiteta tokom diverzifikacije velikih mrmoljaka. Obrasci variranja u basipodijumu su slični medju analiziranim vrstama sa većim variranjem u broju karpalnih nego tarzalnim elemenata. Značajan podatak ove studije je da je u basipodijumu vrste T. dobrogicus došlo do gubitka jednog od karpalnih elemenata (centrale 1). Specifičnost ekstremiteta dunavskog mrmoljka se dopunjuje i posebnim planom organizacije karpusa i tarzusa koji odlikuje nizak nivo osifikacije praćen rastresitim pakovanjem skeletnih lemenata. Sve ove odlike ukazuju na postojanje heterohronične promene (pedomorfoze) kada je u pitanju skelet ekstremiteta. Rezultati ove studije su pokazali značajan uticaj morfološke integracije, modularnosti i razvojnih ograničenja u kreiranju fenotipske varijabilnosti u ekstremitetima velikih krestastih mrmoljaka. Integration, modularity and developmental constraints are three related components of phenotypic variability. Their impacts on morphological evolution on limbs in five species of crested newts were analyzed in this thesis. Crested newts are valuable model organisms in studies of morphological integration and developmental constraints, especially when concern limbs. They are closely related group of species with known phylogenetic relations, and each characterized by a specific body-to-limb conformation associated with their respective ecologies. Aquatic species of newts have small, elongate bodies and small limbs while more terrestrial species are with large, stocky bodies and robust limbs. Also, as group with complex life cycle, where larval, juvenile and adult stage have different morphologies, ecologies and different diet and locomotor preferences, crested newts have special place in studies of changes in ontogenetic trajectories. Ontogenetic niche change and transition between aquatic and terrestrial environment is connected with process of metamorphosis. Although limbs in newts do not undergo drastic changes in structure during that process, functional demands for high efficient locomotion in both environments are quit different. It is assumed that the differences between species in degree of aquatic and terrestrial locomotion may be the factor which can attribute to changes in length of skeletal elements and different patterns of correlations between limb elements, reflecting adaptations on different environments and life styles of analyzed species of crested newts. Analysis of morphological integration and modularity has found different aspects of variation patterns in limbs of crested newts. Equivalent ontogenetic stages of different species of crested newts show higher concordance in the correlation pattern than successive ontogenetic stages within species, with highest level of integration in juvenile stage. High integration in juveniles is function of the rapid, coordinated growth of the limb skeleton during this time period, in which systematic hormones are thought to play a major role. While, low integration in adult stage are probably due to many locally and globally-systematic factors which change effect one to another in time and space, although biphasic life cycle with different locomotion modes have decisive role in ontogenetic changes of morphological integration and modularity. Differences in patterns of integrations between aquatic and more terrestrial species of newts were observed, with lower correlation between homologous limb elements and higher correlation within-limb elements in more terrestrial species, the reverse pattern occurs in more aquatic species. This study showed important role of developmental constraints in creating phenotypic variability in limbs of crested newts. Comparative analyses revealed some synapomorphic heterochronic shifts specific to crested newts, including delay of the ossification in the second finger and accelerations in metacarpal III and metatarsal V. These shifts involve a change from pre-axial to post-axial dominance in a developmental sequence uncommon to caudate salamanders. No adaptive explanation of these shifts is apparent. Allometric analyses showed two important results: specific growth patterns in T.dobrogicus and similar growth pattern after metamorphosis in all species of crested newts. These results are reflecting impact of natural selection as well as internal developmental mechanisms which regulated variation in length of limbs during morphological diversification of crested newts. All studied species shared the same basipodial pattern, within which the carpus exhibited much more variation than the tarsus. Important point in this study is lost of one carpal element (centrale 1). Specific pattern observed in T. dobrogicus is followed with low ossification and loose package of carpale elements. It is suggested that the uniqueness of T. dobrogicus originates from heterochronic process. Results of this study showed important influence of morphological integration, modularity and developmental constraints in creating phenotypic variability in limbs of crested newts.