A new Loriciferan, Scaberiloricus samba gen. et sp. nov., links the Higgins larva and the aberrant Shira larva

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A new genus and species of Loricifera, Scaberiloricus samba gen. et sp. nov., is described from the continental shelf and slope off Rio de Janeiro, Brazil. Adult morphology remains unknown for the new entity, but information is available from three different Higgins larval instars. The Higgins larva of the new species is characterised by a bulbous head and a slender, elongate trunk, separated by a constriction behind the head. The cuticle of the thorax and the posterior part of the head is characterised by numerous longitudinal zigzag folds. The new species and genus shows greatest morphological resemblance with Wataloricus japonicus, and a phylogenetic analysis based on Higgins larval morphological characters suggests that Scaberiloricus gen. nov., Wataloricus, Tenuiloricus, and Patuloricus form a monophyletic group within Pliciloricidae. The analysis furthermore suggests that the Higgins larvae of Scaberiloricus gen. nov. and Wataloricus represent transitional, evolutionary stages towards the highly aberrant Shira larvae, found in species of Tenuiloricus and Patuloricus.

TidsskriftOrganisms Diversity and Evolution
Udgave nummer4
Sider (fra-til)787-809
Antal sider23
StatusUdgivet - 2023

Bibliografisk note

Funding Information:
We would like to thank the PETROBRAS’ Santos Project—Santos Basin Regional Environmental Characterization (PCR-BS) for the support of field sampling, laboratory analysis, and financing, through resources from RD&I investments clauses of Brazilian National Agency of Petroleum, Natural Gas and Biofuels (ANP), the Brazilian Institute for the Environment and Natural Resources (IBAMA) for requiring the research, and the crew of R/V Ocean Stalwart for making material for the present study available. We are furthermore indebted Paula Foltran Gheller and Thais Corbisier for sorting specimens of Loricifera from the extracted meiofauna, and to Shinta Fujimoto for providing line art of Wataloricus japonicus, used in Fig. .

Funding Information:
Scaberiloricus gen. nov. is sister taxon to a clade composed of Wataloricus, Tenuiloricus, and Patuloricus. This latter clade is supported by [C8] the loss of oral teeth in the mouth cone. Opposite to the characters discussed above, we feel more reluctant about how much emphasis we should put on the phylogenetic signal from this reduction. As the character matrix is coded currently, the analysis certainly finds support for the present topology, but a slight modification of the coding actually changes the topology within the clade. If we, as described above, make the character transformation of thoracic plates to zigzag wrinkles ordered, and knock out [C8] regarding the presence of oral teeth, Wataloricus, and Scaberiloricus gen. nov. swap positions. Thus, we still see this as a quite likely alternative topology.

Publisher Copyright:
© 2023, The Author(s).

ID: 374049048