Related Experiment Video
Updated: Aug 26, 2025

Single-Animal, Single-Tube RNA Extraction for Comparison of Relative Transcript Levels via qRT-PCR in the Tardigrade Hypsibius exemplaris
Published on: January 3, 2025
Two new tardigrade genera from New Zealand's Southern Alp glaciers display morphological stasis and parallel
Krzysztof Zawierucha1, Daniel Stec2, Peter K Dearden3
1Department of Animal Taxonomy and Ecology, Adam Mickiewicz University, Poznań, Poland; Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Czech Republic.
Abstract:
Tardigrada is an invertebrate phylum that often constitutes a dominant micrometazoan group on glaciers worldwide. We investigated tardigrades residing in surface ice above the equilibrium line altitude (ELA) on three temperate glaciers of New Zealand's Southern Alps. Morphological, morphometric and multilocus DNA analyses (CO1, 18S rRNA, 28S rRNA, ITS-2) revealed two new genera comprising four species, of which two are formally described here: Kopakaius gen. nov. nicolae sp. nov. and Kararehius gen. nov. gregorii sp. nov. The former is represented by three genetically distinct phyletic lineages akin to species. According to CO1, Kopakaius gen. nov. nicolae sp. nov. inhabits Whataroa Glacier only while the remaining two Kopakaius species occur on Fox and Franz Joseph Glaciers, suggesting low dispersal capabilities. Although morphological characteristics of the new genera could indicate affinity with the subfamily Itaquasconinae, phylogenetic analysis placed them confidently in the subfamily Diphasconinae. Kopakaius gen. nov. lack placoids in the pharynx similar with some Itaquasconinae, whereas dark pigmentation and claw shape aligns them with the glacier-obligate genus, Cryobiotus (subfamily Hypsibiinae), which is an example of parallel evolution. The second genus, Kararehius gen nov. could be classified as Adropion-like (subfamily Itaquasconinae), but differs greatly by genetics (placed in the subfamily Diphasconinae) as well as morphology (e.g., lack of septulum), exemplify deep stasis in Hypsibiidae. Our results suggest that glacier fragmentation during the Pleistocene triggered tardigrade speciation, making it a suitable model for studies on allopatric divergence in glacier meiofauna.
More Related Videos
Related Concept Videos
Speciation Rates
Formation of Species
Diversity of Protists III
Hyperthermophilic Bacteria
Red Algae
Diversity of Protists IV

