Using compensatory base change analysis of internal transcribed spacer 2 secondary structures to identify three new species in Paramacrobiotus (Tardigrada)

Abstract

Species within the tardigrade genus Paramacrobiotus could be distinguished via an analysis of internal transcribed spacer 2 (ITS2) secondary structures. Sequences of P. richtersi and four populations previously treated under provisional names (Paramacrobiotus 'richtersi group' 1 to 4) from different continents were determined and annotated, and their secondary structures were predicted. A tree based on a combined sequence-structure alignment was reconstructed by Neighbor-Joining. The topology obtained is consistent with a tree based on a distance matrix of compensatory base changes (CBCs) between all ITS2 sequence-structure pairs in the global multiple alignment. The CBC analysis, together with 18S rDNA sequences, physiological, biochemical and biophysical data identified three species new to science that are morphologically indistinguishable from P. richtersi. These are formally described under the names Paramacrobiotus fairbanksi sp. nov., P. kenianus sp. nov., and P. palaui sp. nov.

Macrobiotus naskreckiisp. nov., a New Tardigrade (Eutardigrada: Macrobiotidae) of theHufelandiGroup from Mozambique

“…Although, in light of detailed taxonomic studies on other tardigrade taxa e.g. Diphascon pingue group, D. nobilei group, M. hufelandi group, M. harmsworthi group, Milnesium or Paramacrobiotus (e.g., Bertolani and Rebecchi 1993, Pilato et al 2000, Fontuora and Pilato 2007, Schill et al 2010, Kaczmarek et al 2011, Michalczyk et al 2012 and the presence of the cryptic species in Phylum Tardigrada (e.g., Schill et al 2010), it is thought that distribution of this species should be re-evaluated in future studies.…”

“…As a result, the morphological characteristics and cosmopolitan distribution (see e.g., Mc-Innes 1994) of this species are doubtful and the taxon needs a redescription based on the material from the type locality in Ireland. Recently, three cryptic species, diagnosed based on genetic data only and not morphologically different from the population of P. richtersi from Tübingen in Germany were provided (Schill et al 2010). However, Schill et al (2010) did not prepare a true taxonomic redescription of P. richtersi and the taxonomic status is still unclear.…”

“…Recently, three cryptic species, diagnosed based on genetic data only and not morphologically different from the population of P. richtersi from Tübingen in Germany were provided (Schill et al 2010). However, Schill et al (2010) did not prepare a true taxonomic redescription of P. richtersi and the taxonomic status is still unclear. In this situation, the specimens and eggs found in the present study, although morphologically similar to typical P. richtersi are listed as Paramacrobiotus cf.…”

Utility of ITS region sequence and structure for molecular identification of Tilia species from Hyrcanian forests, Iran

“…Within the Tilia genus, CBC analysis was not strong enough to separate individual species. However, although CBC is generally thought to be a sufficient criterion for species separation-the identification of a CBC is indicative of two species-the absence of a CBC-as observed between T. heterophylla and Tilia paucicostata-may not preclude the presence of two distinct species (Schill et al 2010). Fig.…”

A clarification for the subgenera of Paramacrobiotus Guidetti, Schill, Bertolani, Dandekar and Wolf, 2009, with respect to the International Code of Zoological Nomenclature

“…The use of parentheses enclosing the name of the author and the date is not affected by the presence of a subgeneric name, by transfer to a different subgenus within the same genus, by a change of rank within the species group, or by transfer of a subspecies to a different species within the same genus", (ICZN 1999). For this reason the following species names have to be corrected: Paramacrobiotus fairbanksi Schill, Förster, Dandekar & Wolf, 2010, P. intii Kaczmarek, Cytan, Zawierucha, Diduszko & Michalczyk, 2014, P. kenianus Schill, Förster, Dandekar & Wolf, 2010, P. klymenki Pilato, Kiosya, Lisi & Sabella, 2012, P. palaui Schill, Förster, Dandekar & Wolf, 2010and P. pius Lisi, Binda & Pilato, 2016 as they were mistakenly accompanied with parenheses in Kaczmarek et al (2017).…”