02384nas a2200253 4500008004100000020001400041245014700055210006900202260001500271300000800286490000700294520156900301653001501870653001801885653001601903653001601919100001601935700002101951700002801972700002302000700002402023700002102047856006202068 2023 eng d a1759-665300aSizing Up the Onychophoran Genome: Repeats, Introns, and Gene Family Expansion Contribute to Genome Gigantism in Epiperipatus broadwayi0 aSizing Up the Onychophoran Genome Repeats Introns and Gene Famil c15/02/2023 a1-60 v153 a

Genome assemblies are growing at an exponential rate and have proved indispensable for studying evolution but the effort has been biased toward vertebrates and arthropods with a particular focus on insects. Onychophora or velvet worms are an ancient group of cryptic, soil dwelling worms noted for their unique mode of prey capture, biogeographic patterns, and diversity of reproductive strategies. They constitute a poorly understood phylum of exclusively terrestrial animals that is sister group to arthropods. Due to this phylogenetic position, they are crucial in understanding the origin of the largest phylum of animals. Despite their significance, there is a paucity of genomic resources for the phylum with only one highly fragmented and incomplete genome publicly available. Initial attempts at sequencing an onychophoran genome proved difficult due to its large genome size and high repeat content. However, leveraging recent advances in long-read sequencing technology, we present here the first annotated draft genome for the phylum. With a total size of 5.6Gb, the gigantism of the Epiperipatus broadwayi genome arises from having high repeat content, intron size inflation, and extensive gene family expansion. Additionally, we report a previously unknown diversity of onychophoran hemocyanins that suggests the diversification of copper-mediated oxygen carriers occurred independently in Onychophora after its split from Arthropoda, parallel to the independent diversification of hemocyanins in each of the main arthropod lineages.

10ahemocyanin10aPanarthropoda10aPeripatidae10avelvet worm1 aSato, Shoyo1 aCunha, Tauana, J1 ade Medeiros, Bruno, A S1 aKhost, Danielle, E1 aSackton, Timothy, B1 aGiribet, Gonzalo uhttps://academic.oup.com/gbe/article/15/3/evad021/703970402811nas a2200229 4500008004100000022001400041245017900055210006900234260001500303300001200318490000700330520205500337653002602392653001202418653001802430653001302448653001602461100001802477700001602495700002302511856004702534 2020 eng d a1445-522600aSystematics of the Peripatopsis clavigera species complex (Onychophora: Peripatopsidae) reveals cryptic cladogenic patterning, with the description of five new species0 aSystematics of the iPeripatopsis clavigerai species complex Onyc c14/08/2020 a569-5900 v343 a

During the present study, DNA sequence data, gross morphology and scanning electron microscopy (SEM) were used to examine cryptic species boundaries in the velvet worm, Peripatopsis clavigera species complex, from the southern Cape Afrotemperate forest belt in South Africa. Sequence data were generated for the mitochondrial COI and the nuclear 18S rRNA loci and phylogenetically analysed using both a Bayesian inference and a maximum-likelihood approach. Both the COI data and the combined DNA sequence topology (COI+18S) revealed the presence of five clades within the Peripatopsis clavigera species complex, and revealed that specimens from Tulbagh were distantly related and represented a sixth clade. The evolutionary distinction of the five clades was corroborated to varying degrees by the four species-delimitation methods (ABGD, PTP, GMYC and STACEY); however, both the gross morphological data and the SEM provided limited diagnostic differences between the five clades. Furthermore, the COI haplotype network and phylogeographic analyses provided evidence of genetic isolation between lineages that are currently syntopic. The distribution of genealogically exclusive and widespread maternal lineages was atypical among velvet worms and did not reflect the general trend of genetic and geographical isolation. Instead, lineages exhibited admixture among localities, a result most likely due to fluctuations in climatic conditions affecting the southern Cape Afrotemperate forest during the Pliocene–Pleistocene period as evident from our divergence time estimations. Four novel, narrow-range endemic species – P. ferox, sp. nov., P. mellaria, sp. nov., P. edenensis, sp. nov. and P. mira, sp. nov. – are described within the P. clavigera species complex, whereas the Tulbagh specimens are described as P. tulbaghensis, sp. nov. Collectively, these results demonstrate that Peripatopsis likely contains several undescribed species.

10aclimatic amelioration10aendemic10anovel species10asympatry10avelvet worm1 aBarnes, Aaron1 aReiss, Till1 aDaniels, Savel, R. uhttp://www.publish.csiro.au/?paper=IS1907102373nas a2200277 4500008004100000022001400041245007400055210006900129260001500198300001200213490000600225520157100231653001601802653001501818653001601833653003701849653001501886653001601901100002201917700002201939700001601961700001801977700002001995700001702015856006302032 2019 eng d a2054-570300aFunctional morphology of a lobopod: case study of an onychophoran leg0 aFunctional morphology of a lobopod case study of an onychophoran c16/10/2019 a191-2000 v63 a

Segmental, paired locomotory appendages are a characteristic feature of Panarthropoda—a diversified clade of moulting animals that includes onychophorans (velvet worms), tardigrades (water bears) and arthropods. While arthropods acquired a sclerotized exoskeleton and articulated limbs, onychophorans and tardigrades possess a soft body and unjointed limbs called lobopods, which they inherited from Cambrian lobopodians. To date, the origin and ancestral structure of the lobopods and their transformation into the jointed appendages are all poorly understood. We therefore combined high-resolution computed tomography with high-speed camera recordings to characterize the functional anatomy of a trunk lobopod from the onychophoran Euperipatoides rowelli. Three-dimensional reconstruction of the complete set of muscles and muscle fibres as well as non-muscular structures revealed the spatial relationship and relative volumes of the muscular, excretory, circulatory and nervous systems within the leg. Locomotory movements of individual lobopods of E. rowelli proved far more diverse than previously thought and might be governed by a complex interplay of 15 muscles, including one promotor, one remotor, one levator, one retractor, two depressors, two rotators, one flexor and two constrictors as well as muscles for stabilization and haemolymph control. We discuss the implications of our findings for understanding the evolution of locomotion in panarthropods.

 

10amusculature10amyoanatomy10aOnychophora10athree-dimensional reconstruction10atomography10avelvet worm1 aOliveira, Ivo, dS1 aKumerics, Andreas1 aJahn, Henry1 aMüller, Mark1 aPfeiffer, Franz1 aMayer, Georg uhttps://royalsocietypublishing.org/doi/10.1098/rsos.191200