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

Abstract

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'.

Morphological and genetic variability in cosmopolitan tardigrade species - Paramacrobiotus fairbanksi Schill, Förster, Dandekar & Wolf, 2010

“…At present, we have strong and compelling evidence of wide distribution of some tardigrade taxa which means that we return again to the concept of cosmopolitism of at least some species of tardigrades (e.g. ref 8,9,20,21,22 ) which can suggests support the hypothesis 'Everything is Everywhere' (EiE) for tardigrades. There are four tardigrade species known from more than one zoogeographic realm, i.e., Echiniscus testudo 23 (Doyère, 1840) and Milnesium inceptum 24 Morek, Suzuki, Schill, Georgiev, Yankova, Marley & Michalczyk, 2019, Pam.…”

“…There are four tardigrade species known from more than one zoogeographic realm, i.e., Echiniscus testudo 23 (Doyère, 1840) and Milnesium inceptum 24 Morek, Suzuki, Schill, Georgiev, Yankova, Marley & Michalczyk, 2019, Pam. gadabouti 22 Kayastha, Stec, then placed in an incubator and dried for two days at ca. 60°C.…”

Morphological and genetic variability in cosmopolitan tardigrade species - Paramacrobiotus fairbanksi Schill, Förster, Dandekar & Wolf, 2010

“…At present, we have strong and compelling evidence of a wide distribution of some tardigrade taxa, which means that we return to the concept of cosmopolitism of at least some species of tardigrades (e.g. ref 8,9,20,21,22 ) which can support the hypothesis 'Everything is Everywhere' (EiE) for tardigrades. According to Gąsiorek et al 21 , "a species may be termed as cosmopolitan if it was recorded in more than one zoogeographic realm".…”

“…fairbanksi are from Table 1 and Pam. gadabouti from Kayastha et al 22 . The coordinate list is provided in SM.01 and the R script for ENM in SM.02.…”

“…There are four tardigrade species known from more than one zoogeographic realm, i.e., Echiniscus testudo 23 (Doyère, 1840), Milnesium inceptum 24 Morek, Suzuki, Schill, Georgiev, Yankova, Marley & Michalczyk, 2019, Pam. gadabouti 22 Kayastha, Stec, Mioduchowska and Kaczmarek. 2023 and Pam.…”