Integrative redescription of Hypsibius pallidoides Pilato et al., 2011 (Eutardigrada: Hypsibioidea) with the erection of a new genus and discussion on the phylogeny of Hypsibiidae

Abstract

<jats:p>An integrative redescription of Hypsibius pallidoides Pilato, Kiosya, Lisi, Inshina &amp; Biserov, 2011 was undertaken following a reexamination of the type material and new material using high-quality light microscopy, scanning electron microscopy and methods of molecular taxonomy. Detailed morphological investigations revealed a unique complex of characters that precluded the attribution of this species to the genus Hypsibius Ehrenberg, 1848. Furthermore, phylogenetic analyses indicated the affinity of this species within the subfamily Pilatobiinae (Hypsibiidae). Notahypsibius gen. nov. is erected for H. pallidoides and two putatively related species: H. scaber Maucci, 1987 and Ramazzottius arcticus (Murray, 1907). An emended diagnosis for the genus Pilatobius is given, while the subfamily Pilatobiinae lacks a cohesive morphological diagnosis despite representing, at the same time, a well-supported molecular clade. Obvious controversy between the results of the morphological and molecular analyses of the phylogeny of Hypsibioidea is discussed. The distribution of morphological characters such as the claw type, organization of the bucco-pharyngeal apparatus, and egg shell sculpture type within Eutardigrada is analyzed and their phylogenetic significance discussed.</jats:p>

Presence of <em>Notahypsibius pallidoides</em> (Tardigrada: Hypsibiidae) in the fauna of Russia confirmed with the methods of DNA barcoding

“…For the integrative redescription, a newly revealed population from Austria was used. Also, the presence of this species is suspected for Poland (Tumanov, 2020b) and Ireland (Erica De Milio, unpublished data).…”

“…Recently, the tardigrade species Notahypsibius pallidoides (Pilato et al, 2011) was redescribed using an integrative approach, and its phylogenetic position was revised (Tumanov, 2020b). This species was originally described from Kherson Oblast, South Ukraine .…”

“…Later it was recorded in Minsk Oblast, Central Belarus (Pilato, Kiosya, Lisi and Sabella, 2012) and Sicily (Lisi, 2015). Moreover, distribution of this species was extended to Northwest Russia and Croatia (Tumanov, 2020b). For the integrative redescription, a newly revealed population from Austria was used.…”

“…But whereas only the Austrian population has been characterized genetically so far (Tumanov, 2020b), it is possible that other records can represent cryptic species.…”

“…Previously obtained sequences (Tumanov, 2020b) of the same markers for the Austrian population of the species Not. pallidoides (GeneBank accession numbers: MN927182 for ITS-2 and MN918533 for COI) were used for the comparison.…”