A new discovery of Novechiniscus armadilloides (Schuster, 1975) (Tardigrada, Echiniscidae) from Utah, USA with considerations on non-marine Heterotardigrada phylogeny and biogeography

摘要

The discovery of a new population of the non-marine heterotardigrade Novechiniscus armadilloides from Utah, USA, allowed us to reanalyse the species by means of scanning electron microscopy and differential interference contrast microscopy. This analysis confirmed the presence of bar shaped, impaired segmental plates and of a long filament E in addition to the filament A always present in the class Heterotardigrada. It also provided additional information on characters not explicitly cited in the previous descriptions of this monotypic genus, such as details of the head cirri and clavae, details of the buccal tube and pharyngeal bulb, sculpture of the dorso-lateral and leg plates, details of the claws. The population is bisexual, but no secondary sexual dimorphism was observed. The male and female gonopores were described. New characters such as red eyes and red body colour were used in analysing the phylogeny of the family Echiniscidae. The phylogeny and biogeography of non-marine heterotardigrades provide intriguing questions for further research. (C) 2007 Gesellschaft fur Biologische Systematik. Published by Elsevier GmbH. All rights reserved.