O grupo de onicóforos \"caraíbas\" apresenta grande diversidade de espécies, mas também gêneros fracamente delimitados. Epiperipatus Clark, 1913 é o maior dos gêneros neotropicais de Onychophora, mas ainda não sofreu revisão taxanômica. Este gênero foi incorporado no presente estudo, que contemplou o mais abrangente conjunto de dados moleculares, assistido por dados morfológicos. Quatro marcadores moleculares foram utilizados: cytochrome c oxidase subunit I (COI), 12S rRNA, 16S rRNA (mitochondriais) e 18S rRNA (nuclear). Além disso, trinta e três caracteres morfológicos foram levantados. A base de dados foi submetida a duas análises de Máxima Parcimônia (MP) e uma de Máxima Verossimilhança (ML). No total foram examinados 175 espécimes, cobrindo nove gêneros e vinte e nove espécies, dezoito delas pertencentes a Epiperipatus. Foi adotado como hipótese de trabalho o cladograma resultante da análise de evidência total que contemplou os dados moleculares e morfológicos. O resultado mostrou que os dados morfológicos não são capazes de resolver por si só as relações internas de Peripatidae, pois o número de caracteres morfológicos é menor que o número de terminais examinados. Peripatidae é suportado por dados moleculares e isso é conflitante com a delimitação morfológica tradicional dos gêneros da família. Isso demonstra que clados suportados por dados moleculares mostram elevada disparidade morfológica, que pode estar relacionada a adaptação a diferentes ambientes do clado Neotropical. Além disso, o resultado também sugeriu Epiperipatus como parafilético, pois engloba outros gêneros que devem ser sinonimizados. Epiperipatus apresentou estabilidade em três clados neotropicais, apesar de que Epiperipatus edwardsii (Blanchard, 1847) e outros quatro grupos mostraram posição instável. Para reconciliar a sistemática e a filogenia de Epiperipatus, os gêneros monotípicos Principapillatus Oliveira et al., 2014 e Cerradopatus Oliveira et al., 2015 devem ser considerados sinônimo-junior de Epiperipatus. Consequentemente, as novas combinações foram propostas: Epiperipatus hitoyensis (Oliveira et al., 2012) n. comb. e Epiperipatus sucuriuensis (Oliveira et al., 2015) n. comb.. Além disso, foram apresentadas e descritas as espécies novas Epiperipatus [sp1] n. sp., Epiperipatus [sp2] n. sp., Epiperipatus [sp10] n. sp., Epiperipatus [sp16] n. sp. e Epiperipatus [sp17] n. sp.. O enraizamento da filogenia de Onychophora em Peripatopsidae resultou no grupo Neotropical como grupo-irmão do grupo africano, e um aparente ancestral Asiático. A demonstrada monofilia de Epiperipatus confirmou sua larga distribuição, da mesma forma que Peripatus. Ambos os gêneros ocorrem da América Central ao Brasil. Entretanto, no Brasil enquanto Peripatus ocorre apenas no centro-oeste desse país, Epiperipatus é encontrado em quase todo o território desse país, com exceção da região sul / The \"caraibes\" onychophorans present both a large diversity and weakly defined genera. Epiperipatus Clark, 1913 is the largest genus, but it has not been revised so far. This genus is herein incorporated into the currently most comprehensive molecular phylogenetic analysis of Peripatidae, assisted by morphology. Four markers were used: cytochrome c oxidase subunit I (COI), 12S rRNA, 16S rRNA (mitochondrial) and 18S rRNA (nuclear). Moreover, 33 morphological characters were obtained. The dataset was used in two Maximum Parsimony (MP) and one Maximum Likelihood (ML) analyses. In a total of 175 specimens of Onychophora, nine genera and twenty-nine species were examined, eighteen of them belonging to Epiperipatus. We adopted as work hypothesis the MP based on total evidence. The result showed that morphological by itself cannot be used to resolve the phylogenetic relationships of this group, because the number of characters is smaller than the number of terminals examined. Here, Peripatidae was based on molecular data and this conflicts with the characters traditionally used to define genera in the family. It means that clades supported by molecular data shows high morphological disparity which might be reflected on the adaptation to different environments in the Caribbean clade. Also, the result suggests that Epiperipatus seems to be not monophyletic, as it includes others genera and these genera should be synonymized. Epiperipatus presented stable relationships across three clades of Neotropical onychophorans, but it was observed the unstable position of Epiperipatus edwardsii (Blanchard, 1847) and four groups also. To reconcile Epiperipatus systematics with the phylogeny, the monotypic genera Principapillatus Oliveira et al., 2014 and Cerradopatus Oliveira et al., 2015 should be considered as junior synonyms of Epiperipatus. Hence, the new combinations were proposed: Epiperipatus hitoyensis (Oliveira et al., 2012) n. comb. and Epiperipatus sucuriuensis (Oliveira et al., 2015) n. comb.. Moreover, the new species Epiperipatus [sp1] n. sp., Epiperipatus [sp2] n. sp., Epiperipatus [sp10] n. sp., Epiperipatus [sp16] n. sp. and Epiperipatus [sp17] n. sp. were presented and described here. Rooting the Onychophora phylogeny in Peripatopsidae resulted in the Neotropical group as the sister group relationship to the African species, and an apparently ancestral group from Asia. The demonstrated Epiperipatus monophily confirmed its widespread distribution, in the same way as Peripatus. Both are recorded from Central America to Brazil. However, in Brazil, while Peripatus occurs only until the Central-West region, Epiperipatus is found in all Brazilian territories, except in the South region

As one of the closest relatives of arthropods, Onychophora plays an important role in understanding the evolution of arthropod body plans. Currently there is controversy surrounding the evolution of the brain among the ecdysozoan clades, which shows a collar-shaped, circumoral organization in cycloneuralians but a ganglionic architecture in panarthropods. Based on the innervation pattern of lip papillae surrounding the mouth, the onychophoran brain has been interpreted as a circumoral ring, suggesting that this organization is an ancestral feature of Ecdysozoa. However, this interpretation is inconsistent with other published data. To explore the evolutionary origin of the onychophoran mouth and to shed light on the evolution of the ecdysozoan brains, we analyzed the innervation pattern and morphogenesis of the oral lip papillae in the onychophoran Euperipatoides rowelli using DNA labeling, immunocytochemistry, and neuronal tracing techniques. Our morphogenetic data revealed that the seven paired and one unpaired oral lip papillae arise from three anterior-most body segments. Retrograde fills show that only the first and the third nerves supplying the lip papillae are associated with cell bodies within the brain, whereas the second nerve exclusively receives fibers from somata of peripheral neurons located in the lip papillae. According to our anterograde fills and immunocytochemical data, the first nerve supplies the anterior-most pair of lip papillae, whereas the second and the third nerves are associated with the second to fifth and second to eighth lip papillae, respectively. These data suggest that the lip papillae of E. rowelli are mainly innervated by the proto- and deutocerebrum, whereas there are only a few additional cell bodies situated posterior to the brain. According to these findings, the overall innervation pattern of the oral lip papillae in E. rowelli is incompatible with the interpretation of the onychophoran brain as a modified circumoral ring.

O grupo de onicóforos \"caraíbas\" apresenta grande diversidade de espécies, mas também gêneros fracamente delimitados. Epiperipatus Clark, 1913 é o maior dos gêneros neotropicais de Onychophora, mas ainda não sofreu revisão taxanômica. Este gênero foi incorporado no presente estudo, que contemplou o mais abrangente conjunto de dados moleculares, assistido por dados morfológicos. Quatro marcadores moleculares foram utilizados: cytochrome c oxidase subunit I (COI), 12S rRNA, 16S rRNA (mitochondriais) e 18S rRNA (nuclear). Além disso, trinta e três caracteres morfológicos foram levantados. A base de dados foi submetida a duas análises de Máxima Parcimônia (MP) e uma de Máxima Verossimilhança (ML). No total foram examinados 175 espécimes, cobrindo nove gêneros e vinte e nove espécies, dezoito delas pertencentes a Epiperipatus. Foi adotado como hipótese de trabalho o cladograma resultante da análise de evidência total que contemplou os dados moleculares e morfológicos. O resultado mostrou que os dados morfológicos não são capazes de resolver por si só as relações internas de Peripatidae, pois o número de caracteres morfológicos é menor que o número de terminais examinados. Peripatidae é suportado por dados moleculares e isso é conflitante com a delimitação morfológica tradicional dos gêneros da família. Isso demonstra que clados suportados por dados moleculares mostram elevada disparidade morfológica, que pode estar relacionada a adaptação a diferentes ambientes do clado Neotropical. Além disso, o resultado também sugeriu Epiperipatus como parafilético, pois engloba outros gêneros que devem ser sinonimizados. Epiperipatus apresentou estabilidade em três clados neotropicais, apesar de que Epiperipatus edwardsii (Blanchard, 1847) e outros quatro grupos mostraram posição instável. Para reconciliar a sistemática e a filogenia de Epiperipatus, os gêneros monotípicos Principapillatus Oliveira et al., 2014 e Cerradopatus Oliveira et al., 2015 devem ser considerados sinônimo-junior de Epiperipatus. Consequentemente, as novas combinações foram propostas: Epiperipatus hitoyensis (Oliveira et al., 2012) n. comb. e Epiperipatus sucuriuensis (Oliveira et al., 2015) n. comb.. Além disso, foram apresentadas e descritas as espécies novas Epiperipatus [sp1] n. sp., Epiperipatus [sp2] n. sp., Epiperipatus [sp10] n. sp., Epiperipatus [sp16] n. sp. e Epiperipatus [sp17] n. sp.. O enraizamento da filogenia de Onychophora em Peripatopsidae resultou no grupo Neotropical como grupo-irmão do grupo africano, e um aparente ancestral Asiático. A demonstrada monofilia de Epiperipatus confirmou sua larga distribuição, da mesma forma que Peripatus. Ambos os gêneros ocorrem da América Central ao Brasil. Entretanto, no Brasil enquanto Peripatus ocorre apenas no centro-oeste desse país, Epiperipatus é encontrado em quase todo o território desse país, com exceção da região sul / The \"caraibes\" onychophorans present both a large diversity and weakly defined genera. Epiperipatus Clark, 1913 is the largest genus, but it has not been revised so far. This genus is herein incorporated into the currently most comprehensive molecular phylogenetic analysis of Peripatidae, assisted by morphology. Four markers were used: cytochrome c oxidase subunit I (COI), 12S rRNA, 16S rRNA (mitochondrial) and 18S rRNA (nuclear). Moreover, 33 morphological characters were obtained. The dataset was used in two Maximum Parsimony (MP) and one Maximum Likelihood (ML) analyses. In a total of 175 specimens of Onychophora, nine genera and twenty-nine species were examined, eighteen of them belonging to Epiperipatus. We adopted as work hypothesis the MP based on total evidence. The result showed that morphological by itself cannot be used to resolve the phylogenetic relationships of this group, because the number of characters is smaller than the number of terminals examined. Here, Peripatidae was based on molecular data and this conflicts with the characters traditionally used to define genera in the family. It means that clades supported by molecular data shows high morphological disparity which might be reflected on the adaptation to different environments in the Caribbean clade. Also, the result suggests that Epiperipatus seems to be not monophyletic, as it includes others genera and these genera should be synonymized. Epiperipatus presented stable relationships across three clades of Neotropical onychophorans, but it was observed the unstable position of Epiperipatus edwardsii (Blanchard, 1847) and four groups also. To reconcile Epiperipatus systematics with the phylogeny, the monotypic genera Principapillatus Oliveira et al., 2014 and Cerradopatus Oliveira et al., 2015 should be considered as junior synonyms of Epiperipatus. Hence, the new combinations were proposed: Epiperipatus hitoyensis (Oliveira et al., 2012) n. comb. and Epiperipatus sucuriuensis (Oliveira et al., 2015) n. comb.. Moreover, the new species Epiperipatus [sp1] n. sp., Epiperipatus [sp2] n. sp., Epiperipatus [sp10] n. sp., Epiperipatus [sp16] n. sp. and Epiperipatus [sp17] n. sp. were presented and described here. Rooting the Onychophora phylogeny in Peripatopsidae resulted in the Neotropical group as the sister group relationship to the African species, and an apparently ancestral group from Asia. The demonstrated Epiperipatus monophily confirmed its widespread distribution, in the same way as Peripatus. Both are recorded from Central America to Brazil. However, in Brazil, while Peripatus occurs only until the Central-West region, Epiperipatus is found in all Brazilian territories, except in the South region

Arthropods typically show two types of segmentation: the embryonic parasegments and the adult segments that lie out of register with each other. Such a dual nature of body segmentation has not been described from Onychophora, one of the closest arthropod relatives. Hence, it is unclear whether onychophorans have segments, parasegments, or both, and which of these features was present in the last common ancestor of Onychophora and Arthropoda. To address this issue, we analysed the expression patterns of the "segment polarity genes" engrailed, cubitus interruptus, wingless and hedgehog in embryos of the onychophoran Euperipatoides rowelli. Our data revealed that these genes are expressed in repeated sets with a specific anterior-to-posterior order along the body in embryos of E. rowelli. In contrast to arthropods, the expression occurs after the segmental boundaries have formed. Moreover, the initial segmental furrow retains its position within the engrailed domain throughout development, whereas no new furrow is formed posterior to this domain. This suggests that no re-segmentation of the embryo occurs in E. rowelli. Irrespective of whether or not there is a morphological or genetic manifestation of parasegments in Onychophora, our data clearly show that parasegments, even if present, cannot be regarded as the initial metameric units of the onychophoran embryo, because the expression of key genes that define the parasegmental boundaries in arthropods occurs after the segmental boundaries have formed. This is in contrast to arthropods, in which parasegments rather than segments are the initial metameric units of the embryo. Our data further revealed that the expression patterns of "segment polarity genes" correspond to organogenesis rather than segment formation. This is in line with the concept of segmentation as a result of concerted evolution of individual periodic structures rather than with the interpretation of \"segments\" as holistic units.

As one of the closest relatives of arthropods, Onychophora plays an important role in understanding the evolution of arthropod body plans. Currently there is controversy surrounding the evolution of the brain among the ecdysozoan clades, which shows a collar-shaped, circumoral organization in cycloneuralians but a ganglionic architecture in panarthropods. Based on the innervation pattern of lip papillae surrounding the mouth, the onychophoran brain has been interpreted as a circumoral ring, suggesting that this organization is an ancestral feature of Ecdysozoa. However, this interpretation is inconsistent with other published data. To explore the evolutionary origin of the onychophoran mouth and to shed light on the evolution of the ecdysozoan brains, we analyzed the innervation pattern and morphogenesis of the oral lip papillae in the onychophoran Euperipatoides rowelli using DNA labeling, immunocytochemistry, and neuronal tracing techniques. Our morphogenetic data revealed that the seven paired and one unpaired oral lip papillae arise from three anterior-most body segments. Retrograde fills show that only the first and the third nerves supplying the lip papillae are associated with cell bodies within the brain, whereas the second nerve exclusively receives fibers from somata of peripheral neurons located in the lip papillae. According to our anterograde fills and immunocytochemical data, the first nerve supplies the anterior-most pair of lip papillae, whereas the second and the third nerves are associated with the second to fifth and second to eighth lip papillae, respectively. These data suggest that the lip papillae of E. rowelli are mainly innervated by the proto- and deutocerebrum, whereas there are only a few additional cell bodies situated posterior to the brain. According to these findings, the overall innervation pattern of the oral lip papillae in E. rowelli is incompatible with the interpretation of the onychophoran brain as a modified circumoral ring.

No description available.

Arthropods typically show two types of segmentation: the embryonic parasegments and the adult segments that lie out of register with each other. Such a dual nature of body segmentation has not been described from Onychophora, one of the closest arthropod relatives. Hence, it is unclear whether onychophorans have segments, parasegments, or both, and which of these features was present in the last common ancestor of Onychophora and Arthropoda. To address this issue, we analysed the expression patterns of the "segment polarity genes" engrailed, cubitus interruptus, wingless and hedgehog in embryos of the onychophoran Euperipatoides rowelli. Our data revealed that these genes are expressed in repeated sets with a specific anterior-to-posterior order along the body in embryos of E. rowelli. In contrast to arthropods, the expression occurs after the segmental boundaries have formed. Moreover, the initial segmental furrow retains its position within the engrailed domain throughout development, whereas no new furrow is formed posterior to this domain. This suggests that no re-segmentation of the embryo occurs in E. rowelli. Irrespective of whether or not there is a morphological or genetic manifestation of parasegments in Onychophora, our data clearly show that parasegments, even if present, cannot be regarded as the initial metameric units of the onychophoran embryo, because the expression of key genes that define the parasegmental boundaries in arthropods occurs after the segmental boundaries have formed. This is in contrast to arthropods, in which parasegments rather than segments are the initial metameric units of the embryo. Our data further revealed that the expression patterns of "segment polarity genes" correspond to organogenesis rather than segment formation. This is in line with the concept of segmentation as a result of concerted evolution of individual periodic structures rather than with the interpretation of \"segments\" as holistic units.

Onychophorans are closely allied to the arthropods and possess a body organisation more similar to Middle Cambrian fossils than to recent arthropods. This means that onychophorans in some respects can be regarded as a model for the last common ancestor to both the Arthropoda and the Onychophora. This thesis mainly deals with the morphology of the head region of the Onychophora, but developmental investigations of the expression of a key regulatory gene, engrailed, are also carried out. The innervation of the head was found to differ from that reported in earlier investigations. The nerves that support the mouth were found to originate from three different regions of the brain. That innervation pattern suggests that present day onychophorans with a ventrally placed mouth, have evolved from an ancestor with a terminal mouth. Furthermore it was confirmed that the onychophoran structure with the unfortunately chosen term labrum is not homologous to the structure in arthropods that bears this name. Instead it is a muscular outgrowth from the pharynx. The embryological investigations gave further support for an ancestral and terminal mouth. The two most anterior oral lips are first located on the dorso-frontal side of the head, and later migrate to their final position at the ventral side. This phenomenon also explains their somewhat unexpected innervation from the dorsum. It was also established that the eye originates at a position posterior to the antenna. This is reversed compared to the condition in arthropods, were the eye is innervated from the protocerebrum and the first antenna from the dutocerebrum, and implies that the eye and antenna are not serially homologous between the two groups. A structure in the onychophoran head that has gained little attention is the hypocerebral organ, also termed infracerebral organ. It has been suggested as a corpora allata analog by earlier workers. Its ultrastructure was investigated, and great similarities to the corpora allata of the stick insect Carausius morosus were found. However, the lack of innervation of the hypocerebral organ of Onychophora poses a problem since the corpora allata of insects is controlled by nerves. Instead, cellular strands were found that connected the hypocerebral organ with the brain, and it is possible that these strands act as an alternative communication. The expression pattern of the segment polarity gene engrailed was found to be different from that reported in an earlier account of onychophorans. Engrailed was expressed in a subset of developing neurons in the brain anlage and in the ectoderm and mesoderm of the limb buds. The engrailed positive cells in the brain anlage were located in the area were the first commissure will form. This indicates that engrailed might have a function in axon guidance, as has been reported in other organisms. Later embryonic stages showed expression in the neuropile of the brain. There were no indications of this gene acting in determination of segment polarity. This suggests that there may be at least two copies of engrailed in onychophorans.