Examinando por Autor "Worsaae, Katrine"

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Insights into mud dragon morphology (Kinorhyncha, Allomalorhagida): myoanatomy and neuroanatomy of Dracoderes abei and Pycnophyes ilyocryptus.
(Springer, 2020-07) Herranz, Maria; Sørensen, Martin V.; Park, Taeseo; Leander, Brian; Worsaae, Katrine
Comprehensive morphological investigations covering the diversity of metazoan lineages are needed to obtain a complete picture of organ system evolution. Despite the increased amount of studies on lesser-known phyla during the last decades, the gap in knowledge for these lineages is still remarkable. This is the case for kinorhynchs, or mud dragons, where only a few genera, mainly belonging to the major clade Cyclorhagida, have undergone detailed morphological examinations. Here, we explore the neuroanatomy and myoanatomy in the other major clade, Allomalorhagida, through studies of Dracoderes abei and Pycnophyes ilyocryptus by immunochemistry, CLSM, and computational 3D reconstruction. The current phylogenetic position of Dracoderes as a sister group to all the remaining allomalorhagids makes it a key taxon for understanding the evolution of organ systems within Kinorhyncha. Clear segmental arrangement of muscles and nerves was found in the trunk of D. abei and P. ilyocryptus, excluding modifications observed in the posteriormost segments. When comparing current and previous studies of allomalorhagids and cyclorhagids, the nervous system shows a conserved pattern across kinorhynchs, while the musculature shows significant variation among genera. Segmentation in kinorhynchs is restricted to the trunk, including mesoderm (muscles) and ectoderm derivated structures (nerves and glands). The nervous system shows a segmental arrangement in the first eight trunk segments, whereas the last three segments show some deviating arrangements most likely related to a post-hatching development of these segments. The presence of non-segmental trunk muscles is interpreted as adaptations for increased introvert motility and trunk flexibility.
Microbiomes of microscopic marine invertebrates do not reveal signatures of phylosymbiosis
(Nature Research, 2022-05) Boscaro, Vittorio; Holt, Corey C.; Van Steenkiste, Niels W. L.; Herranz, Maria; Irwin, Nick A. T.; Álvarez-Campos, Patricia; Grzelak, Kasia; Holovachov, Oleksander; Kerbl, Alexandra; Mathur, Varsha; Okamoto, Noriko; Piercey, Rebecca S.; Worsaae, Katrine; Leander, Brian S.; Keeling, P. J.
Animals and microorganisms often establish close ecological relationships. However, much of our knowledge about animal microbiomes comes from two deeply studied groups: vertebrates and arthropods. To understand interactions on a broader scale of diversity, we characterized the bacterial microbiomes of close to 1,000 microscopic marine invertebrates from 21 phyla, spanning most of the remaining tree of metazoans. Samples were collected from five temperate and tropical locations covering three marine habitats (sediment, water column and intertidal macroalgae) and bacterial microbiomes were characterized using 16S ribosomal RNA gene sequencing. Our data show that, despite their size, these animals harbour bacterial communities that differ from those in the surrounding environment. Distantly related but coexisting invertebrates tend to share many of the same bacteria, suggesting that guilds of microorganisms preferentially associated with animals, but not tied to any specific host lineage, are the main drivers of the ecological relationship. Host identity is a minor factor shaping these microbiomes, which do not show the same correlation with host phylogeny, or ‘phylosymbiosis’, observed in many large animals. Hence, the current debate on the varying strength of phylosymbiosis within selected lineages should be reframed to account for the possibility that such a pattern might be the exception rather than the rule.
Myoanatomy of three aberrant kinorhynch species: similar but different?
(Springer, 2021-02) Herranz, Maria; Worsaae, Katrine; Park, Taeseo; Di Domenico, Maikon; Leander, Brian S.; Sørensen, Martin V.
Aberrant kinorhynchs show several modifications deviating from the typical kinorhynch body plan, including a modified introvert with very elongated and flexible scalids, a weakly developed neck, and a slender trunk with less distinct segmentation. How these aberrant external features are reflected in the inner anatomy and how their aberrant body plan evolved are not understood. Here, we provide a comprehensive and comparative myoanatomical study of three putatively, distantly related worm-like species: Cateria styx, Franciscideres kalenesos and Zelinkaderes yong. Despite the weak external segmentation of the trunk, the studied species show a distinct segmental arrangement of the musculature. However, this arrangement is shifted posteriorly with respect to the external segmentation, because the extremely thin and flexible cuticle is lacking the apodeme-like cuticular thickenings (pachycycli) where the longitudinal muscles usually attach. The muscular arrangement in the three species is overall similar, yet, C. styx shows most resemblance to the allomalorhagid F. kalenesos, whereas the cyclorhagid Z. yong differs in several ways. This suggests a closer relationship of C. styx to Allomalorhagida. Whereas most kinorhynchs prefer muddy sediments, both the allomalorhagid and cyclorhagid worm-like kinorhynchs are mainly found in sandy environments, suggesting that a flexible, slender body evolved at least twice independently as an adaptation to the interstitial environment.
Phylogenomic analyses of mud dragons.
(Elsevier, 2022-03) Herranz, Maria; Stiller, Josefin; Worsaae, Katrine; Sørensen, Martin V.
Mud dragons (Kinorhyncha) are microscopic invertebrates, inhabiting marine sediments across the globe from intertidal to hadal depths. They are segmented, moulting animals like arthropods, but grouping with the unsegmented priapulans and loriciferans within Ecdysozoa. There are more than 300 species of kinorhynchs described within 31 genera and 11 families, however, their evolutionary relationships have so far only been investigated using morphology and a few molecular markers. Here we aim to resolve the relationships and classification of major clades within Kinorhyncha using transcriptomic data. In addition, we wish to revisit the position of three indistinctly segmented, aberrant genera in order to reconstruct the evolution of distinct segmentation within the group. We conducted a phylogenomic analysis of Kinorhyncha including 21 kinorhynch transcriptomes (of which 18 are new) representing 15 genera, and seven outgroups including priapulan, loriciferan, nematode and nematomorph transcriptomes. Results show a congruent and robust tree that supports the division of Kinorhyncha into two major clades: Cyclorhagida and Allomalorhagida. Cyclorhagida is composed of three subclades: Xenosomata, Kentrorhagata comb. nov. (including the aberrant Zelinkaderes) and Echinorhagata. Allomalorhagida is composed of two subclades: Pycnophyidae and Anomoirhaga nom. nov. Anomoirhaga nom. nov. accommodates the aberrant genera Cateria (previously nested within Cyclorhagida) and Franciscideres together with five additional genera. The distant and derived positions of the aberrant Zelinkaderes, Cateria and Franciscideres species suggest that their less distinct trunk segmentation evolved convergently, and that segmentation evolved among kinorhynch stem groups.
Revisiting kinorhynch segmentation: variation of segmental patterns in the nervous system of three aberrant species
(BMC, 2021-10) Herranz, Maria; Park, Taeseo; Di Domenico, Maikon; Leander, Brian; Sørensen, Martin V.; Worsaae, Katrine
Background: Kinorhynch segmentation differs from the patterns found in Chordata, Arthropoda and Annelida which have coeloms and circulatory systems. Due to these differences and their obsolete status as ‘Aschelminthes’, the microscopic kinorhynchs are often not acknowledged as segmented bilaterians. Yet, morphological studies have shown a conserved segmental arrangement of ectodermal and mesodermal organ systems with spatial correspondence along the anterior-posterior axis. However, a few aberrant kinorhynch lineages present a worm-like body plan with thin cuticle and less distinct segmentation, and thus their study may aid to shed new light on the evolution of segmental patterns within Kinorhyncha. Results: Here we found the nervous system in the aberrant Cateria styx and Franciscideres kalenesos to be clearly segmental, and similar to those of non-aberrant kinorhynchs; hereby not mirroring their otherwise aberrant and posteriorly shifted myoanatomy. In Zelinkaderes yong, however, the segmental arrangement of the nervous system is also shifted posteriorly and misaligned with respect to the cuticular segmentation. Conclusions: The morphological disparity together with the distant phylogenetic positions of F. kalenesos, C. styx and Z. yong support a convergent origin of aberrant appearances and segmental mismatches within Kinorhyncha.