TY - JOUR
T1 - Untangling the Echiniscus Gordian knot
T2 - Stellariscus gen. nov. (Heterotardigrada: Echiniscidae) from Far East Asia
AU - Gasiorek, Piotr
AU - Suzuki, Atsushi C.
AU - Kristensen, Reinhardt M.
AU - Lachowska-Cierlik, Dorota
AU - Michalczyk, Łukasz
N1 - Funding Information:
We are very grateful to Diane Nelson and two anonymous referees for their effort in improving this paper. The authors also acknowledge Olivier Gerriet (Muséum d’Histoire Naturelle de Nice, France) for sending photos of the E. pseudelegans paratype. The study was supported by a grant from the European Commission’s (FP6) Integrated Infrastructure Initiative program SYNTHESYS (grant no. DK-TAF-6332 to PG) and by Jagiellonian University (subsidy no. K/ZDS/007357 to ŁM).
Publisher Copyright:
© CSIRO.
PY - 2018
Y1 - 2018
N2 - Species constituting the family Echiniscidae are highly derived, armoured and inhabit terrestrial habitats, in contrast to other heterotardigrades that are predominantly marine. The genus Echiniscus C.A.S. Schultze, 1840, nominal for the family Echiniscidae, is currently the most speciose tardigrade genus. However, the great morphological variability, in comparison with other heterotardigrade genera, suggests the polyphyletic character of the genus. Here, we analyse new specimens of Echiniscus pseudelegans Séméria, 1994 collected in Japan and conclude that the species as well as two other related taxa, E. elegans Richters, 1907 and E. latifasciatus Dudichev and Biserov, 2000, represent a new genus, Stellariscus, gen. nov. The new genus is characterised by a mixture of peculiar morphological apomorphies: black eyes, star-like dorsal plate sculpturing, no trunk appendages (only cephalic cirri present), two types of ventral plates, and striking sexual dimorphism in both qualitative and quantitative traits. Morphological phylogeny of the family Echiniscidae suggests a close affinity between Stellariscus, Hypechiniscus Thulin, 1928 and Pseudechiniscus Thulin, 1911. The polyphyletic status of both Echiniscus and Testechiniscus Kristensen, 1987 is also inferred. The taxonomic significance of ventral armature in echiniscid phylogeny and taxonomy is discussed.
AB - Species constituting the family Echiniscidae are highly derived, armoured and inhabit terrestrial habitats, in contrast to other heterotardigrades that are predominantly marine. The genus Echiniscus C.A.S. Schultze, 1840, nominal for the family Echiniscidae, is currently the most speciose tardigrade genus. However, the great morphological variability, in comparison with other heterotardigrade genera, suggests the polyphyletic character of the genus. Here, we analyse new specimens of Echiniscus pseudelegans Séméria, 1994 collected in Japan and conclude that the species as well as two other related taxa, E. elegans Richters, 1907 and E. latifasciatus Dudichev and Biserov, 2000, represent a new genus, Stellariscus, gen. nov. The new genus is characterised by a mixture of peculiar morphological apomorphies: black eyes, star-like dorsal plate sculpturing, no trunk appendages (only cephalic cirri present), two types of ventral plates, and striking sexual dimorphism in both qualitative and quantitative traits. Morphological phylogeny of the family Echiniscidae suggests a close affinity between Stellariscus, Hypechiniscus Thulin, 1928 and Pseudechiniscus Thulin, 1911. The polyphyletic status of both Echiniscus and Testechiniscus Kristensen, 1987 is also inferred. The taxonomic significance of ventral armature in echiniscid phylogeny and taxonomy is discussed.
KW - Echiniscoidea
KW - cuticle
KW - morphology
KW - phylogeny
KW - polyphyly
KW - sexual dimorphism
KW - ventral plates
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U2 - 10.1071/IS18023
DO - 10.1071/IS18023
M3 - Review article
AN - SCOPUS:85055321646
SN - 1445-5226
VL - 32
SP - 1234
EP - 1247
JO - Invertebrate Systematics
JF - Invertebrate Systematics
IS - 5
ER -
