New Echiniscidae (Heterotardigrada) from Amber Mountain (Northern Madagascar)

A moss sample from the local biodiversity hotspot in lowland rainforest in the vicinity of Amber Mountain, Madagascar, yielded the discovery of two Echiniscus C.A.S. Schultze, 1840 species, of which one is new to science. Echiniscus succineus sp. nov. is related to other members of the spinulosus group, but differs from them by the highly complicated structure of the dorsal plates, with intricately thickened parts of the armour forming ornamented pattern. The validity of the intraporal dark rings as a taxonomic trait is discussed in the context of the recovered intraspecific variability for the new taxon. Besides, rare Echiniscus africanus Murray, 1907 is reported for the first time from the island

New Echiniscidae (Heterotardigrada) from Amber Mountain (Northern Madagascar)

A moss sample from the local biodiversity hotspot in lowland rainforest in the vicinity of Amber Mountain, Madagascar, yielded the discovery of two Echiniscus C.A.S. Schultze, 1840 species, of which one is new to science. Echiniscus succineus sp. nov. is related to other members of the spinulosus group, but differs from them by the highly complicated structure of the dorsal plates, with intricately thickened parts of the armour forming ornamented pattern. The validity of the intraporal dark rings as a taxonomic trait is discussed in the context of the recovered intraspecific variability for the new taxon. Besides, rare Echiniscus africanus Murray, 1907 is reported for the first time from the island

Pseudechiniscus in Japan : re-description of "Pseudechiniscus asper" Abe et al., 1998 and description of Pseudechiniscus shintai sp. nov.

The classification and identification of species within the genus Pseudechiniscus Thulin, 1911 has been considered almost a Sisyphean work due to an extremely high homogeneity of its members. Only recently have several contributions made progress in the taxonomy feasible through their detailed analyses of morphology and, crucially, by the re-description of the ancient, nominal species P. suillus (Ehrenberg, 1853). Herein, we focus on the Japanese representatives of this genus: P. asper, a rare species originally described from Hokkaido, and a new species P. shintai. Both taxa belong to the widespread suillus-facettalis complex. Detailed descriptions entailing DNA barcoding of four markers and illustrations of the ventral pillar patterns are indispensable for an accurate delineation of species within this genus

Neotropical jewels in the moss : biodiversity, distribution and evolution of the genus Barbaria (Heterotardigrada: Echiniscidae)

The genus Barbaria, recently established to accommodate the former Echiniscus bigranulatus group, is a tardigrade group emblematic for the South American tardigrade fauna. This unappendaged echiniscid lineage is widely recognized for the so-called ‘double’ sculpturing composed of endocuticular pillars and pseudopores or pores in the dorsal cuticle. The phylogenetic relationships in the genus have so far been completely unknown, but the discovery of two new species (B. paucigranulata sp. nov. and B. weglarskae sp. nov.), together with new genetic data for further six species (B. bigranulata, B. charrua comb. nov., B. danieli, B. jenningsi, B. madonnae and B. ollantaytamboensis), create an opportunity not only to uncover phyletic relationships, but also to reconstruct morphological evolution in the genus. To achieve this, we sequenced five genetic markers (18S rRNA, 28S rRNA, ITS1, ITS2, COI) for multiple populations of eight species of Barbaria (two-thirds of all known species) collected in Alabama (USA), Argentina and the Antarctic, and we analysed them in tandem with detailed morphological data. Our phylogentic analysis and the reconstruction of evolution of morphological traits suggests that the ancestor of the genus inhabited the Neotropics, and it was morphologically most similar to B. bigranulata. We also analyse literature records of Barbaria and conclude that the genus is most likely limited to the Neotropics, Antarctica and southern parts of the Nearctic. The findings are discussed in the context of the phylogeny of the Echiniscus evolutionary line

Phylogeography and morphological evolution of Pseudechiniscus (Heterotardigrada: Echiniscidae)

Tardigrades constitute a micrometazoan phylum usually considered as taxonomically challenging and therefore difficult for biogeographic analyses. The genus Pseudechiniscus, the second most speciose member of the family Echiniscidae, is commonly regarded as a particularly difficult taxon for studying due to its rarity and homogenous sculpturing of the dorsal plates. Recently, wide geographic ranges for some representatives of this genus and a new hypothesis on the subgeneric classification have been suggested. In order to test these hypotheses, we sequenced 65 Pseudechiniscus populations extracted from samples collected in 19 countries distributed on 5 continents, representing the Neotropical, Afrotropical, Holarctic, and Oriental realms. The deep subdivision of the genus into the cosmopolitan suillus-facettalis clade and the mostly tropical-Gondwanan novaezeelandiae clade is demonstrated. Meridioniscus subgen. nov. is erected to accommodate the species belonging to the novaezeelandiae lineage characterised by dactyloid cephalic papillae that are typical for the great majority of echiniscids (in contrast to pseudohemispherical papillae in the suillus-facettalis clade, corresponding to the subgenus Pseudechiniscus). Moreover, the evolution of morphological traits (striae between dorsal pillars, projections on the pseudosegmental plate IV’, ventral sculpturing pattern) crucial in the Pseudechiniscus taxonomy is reconstructed. Furthermore, broad distributions are emphasised as characteristic of some taxa. Finally, the Malay Archipelago and Indochina are argued to be the place of origin and extensive radiation of Pseudechiniscus

Small is beautiful : the first phylogenetic analysis of Bryodelphax Thulin, 1928 (Heterotardigrada, Echiniscidae)

The phyletic relationships both between and within many of tardigrade genera have been barely studied and they remain obscure. Amongst them is the cosmopolitan Bryodelphax, one of the smallest in terms of body size echiniscid genera. The analysis of newly-found populations and species from the Mediterranean region and from South-East Asia gave us an opportunity to present the first phylogeny of this genus, which showed that phenotypic traits used in classical Bryodelphax taxonomy do not correlate with their phyletic relationships. In contrast, geographic distribution of the analysed species suggests their limited dispersal abilities and seems to be a reliable predictor of phylogenetic affinities within the genus. Moreover, we describe three new species of the genus. Bryodelphax australasiaticus sp. nov., by having the ventral plate configuration VII:4-4-2-4-2-2-1, is a new member of the weglarskae group with a wide geographic range extending from the Malay Peninsula through the Malay Archipelago to Australia. Bryodelphax decoratus sp. nov. from Central Sulawesi (Celebes) also belongs to the weglarskae group (poorly visible ventral plates VII:4-2-2-4-2-2-1) and is closely related to the recently described Bryodelphax arenosus Gąsiorek, 2018, but is differentiated from the latter by well-developed epicuticular granules on the dorsum. Finally, a new dioecious species, Bryodelphax nigripunctatus sp. nov., is described from Mallorca and, by the reduced ventral armature (II/III:2-2-(1)), it resembles Bryodelphax maculatus Gąsiorek et al., 2017. The latter species, known so far only from northern Africa, is recorded from Europe for the first time. A taxonomic key to the genus members is also presented

Clarification of the taxonomic status of Acanthochitona discrepans (Brown, 1827) with new data for the North-East Atlantic Acanthochitona (Polyplacophora, Acanthochitonidae)

The genus Acanthochitona can be easily distinguished from other chitons by having eighteen tufts of bristles on the dorsal side of the densely spiculose girdle. In the North-East Atlantic, five species of this genus have been recognised so far: A. crinita (Pennant, 1777), A. discrepans (Brown, 1827), A. fascicularis (Linnaeus, 1767), A. oblonga Leloup, 1968 and A. pilosa Schmidt-Petersen, Schwabe et Haszprunar, 2015. The nomenclature of A. crinita, A. discrepans and A. fascicularis was confused for a very long time until Kaas (1985) designated type specimens for them and provided a brief key. However, his work lacked detailed descriptions of the three species and some authors doubted that A. discrepans constitutes a separate species. Subsequently, the taxonomic status of A. discrepans has remained unclear.Here, we implemented an integrative approach which combined morphology and molecular evidence to show that Acanthochitona discrepans is, indeed, a valid species and we present re-descriptions for A. crinita, A. discrepans and A. fascicularis

Brak poparcia filogenetycznego na wyniesienie podrodzajów w obrębie Pseudechiniscus Thulin, 1911 (Tardigrada)

Ostatnie lata przyniosły wiele zmian w taksonomii niesporczaków dzięki zastosowaniu metod molekularnych, gdyż uprzednio związki zarówno wewnątrz taksonów, jak i między nimi, określano wyłącznie na podstawie cech morfologicznych. W rezultacie grupowania fenotypowego, powiązania ewolucyjne między wieloma taksonami pozostawały nieznane. Jednym z takich taksonów jest rodzaj Pseudechiniscus Thulin, 1911, dookoła którego pozycji systematycznej przez lata powstało wiele zamieszania. Mimo prób uczynienia rodzaju monofiletycznym, znacząca heterogeniczność morfologiczna sugeruje, że Pseudechiniscus wciąż pozostaje polifiletyczny. Próby wyjaśnienia powiązań w obrębie Pseudechiniscus doprowadziły do klasyfikacji jego członków w dwóch liniach ewolucyjnych: kompleksach novaezeelandiae i suillus-facettalis, która opiera się na morfologii i jednej analizie molekularnej opartej na niewielkiej próbie. Gatunki należące do pierwszej grupy cechują się obecnością przydatków (kolce, płaty) na płytce pseudosegmentalnej IV’ oraz wydłużoną i cylindryczną papillą głowową, podczas gdy gatunki należące do grupy suillus-facettalis nie mają żadnych dodatkowych przydatków, a ich papille mają kształt kopulasty. W mojej pracy zastosowałam podejście integratywne obejmujące sekwencjonowanie trzech markerów jądrowych: 18S rRNA, 28S rRNA i ITS-1 oraz analizy morfologiczne, aby rozwiązać relacje między osiemnastoma populacjami gatunków Pseudechiniscus z Europy, Ameryki Północnej, Afryki i Azji. Wyniki pokazały, że nie ma zbieżności pomiędzy cechami morfologicznymi a topologią drzew filogenetycznych. W konsekwencji, ostatnio zaproponowana klasyfikacja Pseudechiniscus jest sztuczna i nie ma wsparcia filogenetycznego, więc może służyć jedynie jako kryterium taksonomiczne, np. jako ułatwienie przy identyfikacji gatunków. Podkreśliłam również potrzebę dalszych badań, aby rozwikłać powiązania w obrębie rodzaju.Recent years have brought many shifts in the taxonomy of tardigrades thanks to the application of molecular techniques, since previously the relationships within and between the taxa were established solely on morphological traits. In the result of phenotype grouping, evolutionary relationships between many taxa remained unsolved. One such taxon is the genus Pseudechiniscus Thulin, 1911, around whose systematic position a lot of confusion has arisen through years. Despite attempts to make this genus monophyletic, considerable morphological heterogeneity suggests that Pseudechiniscus still remains polyphyletic. The attempts of formally establishing the relationships within Pseudechiniscus resulted in the grouping of its members in two lineages: novaezeelandiae and suillus-facettalis complexes, which was based on morphology and on a single molecular analysis based on a limited sample size. The species representing the former are characterised by the presence of appendages (spines, lobes) on the pseudosegmental plate IV’ and elongated-cylindrical cephalic papillae, whereas the species of the suillus-facettalis group have no such additional appendages and possess dome–like shaped papillae. In this study, I applied the integrative approach involving sequencing of three nuclear markers: 18S rRNA, 28S rRNA, and ITS-1, and morphological analyses to resolve relationships between eighteen populations of Pseudechiniscus spp. from Europe, North America, Africa and Asia. The results showed that there is no congruency between the morphological characters and the topology of the phylogenetic trees. Consequently, the recently hypothesised classification of Pseudechiniscus is artificial and has no phylogenetic support, thus it can be used only as a practical taxonomic criterion, e.g. for the easiness of species identification. I also stress the need for the further research to disentangle the interrelationships within the genus

FIGURE 3 in Atlas of the Echiniscidae (Heterotardigrada) of the World-part I: West Palaearctic Echiniscus species

FIGURE 3. Echiniscus azoricus from Madeira (PCM): A—female in dorsal view, B—close-up on paired segmental plate II, C—close-up on median plate 2, D—claws I and spine I. Scale bars in μm.Published as part of Gąsiorek, Piotr & Vončina, Katarzyna, 2023, Atlas of the Echiniscidae (Heterotardigrada) of the World-part I: West Palaearctic Echiniscus species, pp. 1-72 in Zootaxa 5344 (1) on page 12, DOI: 10.11646/zootaxa.5344.1.1, http://zenodo.org/record/834605

FIGURE 13 in Atlas of the Echiniscidae (Heterotardigrada) of the World-part I: West Palaearctic Echiniscus species

FIGURE 13. Echiniscus lapponicus from Norway (PCM, females in dorsal view). Arrowhead points out a minuscule spine I. Scale bars = 50 μm.Published as part of Gąsiorek, Piotr & Vončina, Katarzyna, 2023, Atlas of the Echiniscidae (Heterotardigrada) of the World-part I: West Palaearctic Echiniscus species, pp. 1-72 in Zootaxa 5344 (1) on page 31, DOI: 10.11646/zootaxa.5344.1.1, http://zenodo.org/record/834605