Integrative taxonomy reveals new, widely distributed tardigrade species of the genus Paramacrobiotus (Eutardigrada: Macrobiotidae)

In a moss sample collected in Ribeiro Frio, Madeira, Paramacrobiotus gadabouti sp. nov. was found and described using the integrative taxonomy approach. The new species is described based on morphological and morphometric data from both phase-contrast light microscopy (PCM), as well as scanning electron microscopy (SEM). Moreover, four DNA markers, three nuclear (18S rRNA, 28S rRNA, ITS-2) and one mitochondrial (COI) markers, were used to elucidate the phylogenetic position of the new species within the family Macrobiotidae. The new species has a microplacoid that placed it within Parmacrobiotus richtersi group and exhibit richtersi-type eggs having processes terminated with cap-like structures. Paramacrobiotus gadabouti sp. nov. is most similar to Pam. alekseevi, Pam. filipi and Pam. garynahi, but differs from them mainly in details of egg morphology and morphometrics. Unlike other species from this group, which were confirmed as bisexual and showed limited distribution, Paramacrobiotus gadabouti sp. nov. is yet another parthenogenetic species with a wide distribution, demonstrating that at least some tardigrades confirm to the hypothesis of 'everything is everywhere'.

Automated summary

A new species, Paramacrobiotus gadabouti sp. nov., was discovered and described using morphological, morphometric, and genetic data. The species belongs to the Parmacrobiotus richtersi group and exhibits richtersi-type eggs with cap-like structures at the ends. It is most similar to Pam. alekseevi, Pam. filipi, and Pam. garynahi, but differs in egg morphology and morphometrics. Unlike other species in the group, Paramacrobiotus gadabouti sp. nov. is a parthenogenetic species with a wider distribution, supporting the hypothesis of 'everything is everywhere' for tardigrades.