Paul J. Bartels

The Zoogeography of Marine Tardigrada

This monograph describes the global records of marine water bears (Phylum Tardigrada). We provide a comprehensive list of marine tardigrades recorded from around the world, providing an up-to-date taxonomy and a complete bibliography accompanied by geographic co-ordinates, habitat, substrate and biogeographic comments. A link is provided to an on-line interactive map where all occurrences for each species are shown. In total we list 197 taxa and their 2240 records from 39 oceans and seas and 18 Major Fishing Areas (FAO). It is hoped this work will serve as a reference point and background for further zoogeographic and taxonomic studies on marine tardigrades.

Ramazzottius belubellus, a new species of Tardigrada (Eutardigrada: Parachela: Hypsibiidae) from the Great Smoky Mountains National Park (North Carolina, U.S.A.)

Abstract A new species, Ramazzottius belubellus, is described from a single lichen sample collected in the Great Smoky Mountains National Park in western North Carolina, U.S.A. The new species is easily distinguishable from all other members of the genus Ramazzottius by the presence of long dorsal, sharp triangular spines not arranged in transverse bands as opposed to small tubercles arranged in bands, or a thin reticulum, or a smooth cuticle present in all other described species of the genus. The new species could be confused with R. baumanni but differs from it by the presence of sharp triangular spines on the dorsal side of the body instead of flat, hemispherical tubercles.

Three new species and one new record of the genus Doryphoribius Pilato, 1969 (Tardigrada: Eutardigrada: Hypsibiidae) from the Great Smoky Mountains National Park (Tennessee, USA)

Three new eutardigrades, Doryphoribius longistipes sp. nov., Doryphoribius minimus sp. nov. and Doryphoribius tergumrudis sp. nov., are described from stream periphyton, rock lichen and cave soil and leaf litter samples collected in the limestone‐based Cades Cove area of the Great Smoky Mountains National Park in eastern Tennessee, USA. Doryphoribius longistipes sp. nov. differs from other species mainly by the higher ratio of the secondary to the primary claw branches. Doryphoribius minimus sp. nov. differs from D. gibber, D. mariae and D. vietnamensis mainly by its smaller body size and different arrangement of dorsal gibbosities. Doryphoribius tergumrudis sp. nov. differs from D. evelinae by the absence of gibbosities and tubercles on legs I–III, the presence of lunulae and the absence of eyes. Additionally the three new species differ from other congeners by some other morphological and morphometric characters. Another species, Doryphoribius doryphorus Binda and Pilato, 1969, is a new record for Tennessee.

A Hypothesis for the Composition of the Tardigrade Brain and its Implications for Panarthropod Brain Evolution

Incredibly disparate brain types are found in Metazoa, which raises the question of how this disparity evolved. Ecdysozoa includes representatives that exhibit ring-like brains-the Cycloneuralia-and representatives that exhibit ganglionic brains-the Panarthropoda (Euarthropoda, Onychophora, and Tardigrada). The evolutionary steps leading to these distinct brain types are unclear. Phylogenomic analyses suggest that the enigmatic Tardigrada is a closely related outgroup of a Euarthropoda + Onychophora clade; as such, the brains of tardigrades may provide insight into the evolution of ecdysozoan brains. Recently, evolutionarily salient questions have arisen regarding the composition of the tardigrade brain. To address these questions, we investigated brain anatomy in four tardigrade species-Hypsibius dujardini, Milnesium n. sp., Echiniscus n. sp., and Batillipes n. sp.-that together span Tardigrada. Our results suggest that general brain morphology is conserved across Tardigrada. Based on our results we present a hypothesis that proposes direct parallels between the tardigrade brain and the segmental trunk ganglia of the tardigrade ventral nervous system. In this hypothesis, brain neuropil nearly circumscribes the tardigrade foregut. We suggest that the tardigrade brain retains aspects of an ancestral cycloneuralian brain, while exhibiting ganglionic structure characteristic of euarthropods and onychophorans.

Aquatic tardigrades in the Great Smoky Mountains National Park, North Carolina and Tennessee, U.S.A., with the description of a new species of Thulinius (Tardigrada, Isohypsibiidae)

As part of the All Taxa Biodiversity Inventory (http://www.dlia.org), an extensive survey of tardigrades has been conducted in the Great Smoky Mountains National Park (GSMNP) in Tennessee and North Carolina, U.S.A., by Bartels and Nelson. Freshwater tardigrades include three species in the aquatic genus Thulinius (Eutardigrada, Isohypsibiidae). A new species, Thulinius romanoi, described from stream sediment, is distinguished from all other congeners by having a sculptured cuticle. In addition, the presence of Thulinius augusti (Murray, 1907) was verified by combined morphological and molecular analysis, and nine specimens of a third species, Thulinius cf. saltursus, were also found. Thulinius augusti is a new record for the United States. Thulinius saltursus (Schuster, Toftner & Grigarick, 1978) was previously recorded in California and Ohio, but our specimens vary slightly in morphology. The list of tardigrades from streams in the GSMNP was updated to a total of 44 species, 22 of which were predominantly or exclusively aquatic.

Marine tardigrades of the Bahamas with the description of two new species and updated keys to the species of Anisonyches and Archechiniscus

This is the first survey of subtidal marine tardigrades from the Bahamas, and we compare our results with earlier studies of Bahamian intertidal habitats. In 2011 and 2014 we collected 60 subtidal sand samples from Bimini, the Berry Islands, New Providence, Eleuthera, and the Exumas. We found 11 species only one of which, Dipodarctus subterraneus (Renaud-Debyser, 1959), had been found in the previous intertidal Bahamian collections. Thus, 10 species are new records for the Bahamas, and four of these are new to science. We describe two of the new species (Archechiniscus bahamensis sp. nov. and Anisonyches eleutherensis sp. nov.). Additional material is needed for a conclusive identification of the undescribed species of Batillipes and Florarctus. Based on examination of the holotype of Anisonyches diakidius Pollock, 1975, we redescribe this species and give an emended diagnosis of the genus and the species. We also provide new keys to the species in the genera Archechiniscus and Anisonyches. A Chao2 species richness estimate indicated that our sampling effort was extensive and probably recovered most common species. Correlations of abundance and diversity indices with regard to depth, distance to nearest shore, and sediment grain size were not significant.

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

The recent re-description of Paramacrobiotus Guidetti, Schill, Bertolani, Dandekar and Wolf, 2009 has inadvertently led to the description of an objective synonym within its subgenera nominal taxa. To resolve this issue, we have re-described both subgenera, and proposed a new substitute name for one subgenus, in line with the International Code of Zoological Nomenclature. Additionally we have confirmed the placement of two recently published Paramacrobiotus species, not included in the last revision, within the respective subgenera established herein.

On the distribution of Batillipes tubernatis Pollock, 1971 (Arthrotardigrada: Batillipedidae) in the Atlantic Basin

Specimens of Batillipes tubernatis Pollock, 1971 collected from the Portuguese coast (Lusitanian sea province) indicated a considerable southward extension in the distribution of the species along the northeast Atlantic Ocean. Based on the examination of these specimens and those of Pollock’s collection from the type locality (Scotland), it can also be concluded that the redescription of B. tubernatis based on specimens from the Gulf of Mexico (tropical northwest Atlantic Ocean) does not correspond to that species. Several differences, namely in the shape of cephalic appendages, toe discs and pattern of cuticular sculpture, clearly distinguish specimens of B. tubernatis from those collected in the Gulf of Mexico that certainly belong to a new unnamed species. Moreover, the examination of specimens previously collected in the southwest Atlantic Ocean (Brazil) and attributed to B. tubernatis showed that they belong to other undescribed new Batillipes species, suggesting that B. tubernatis does not occur in that region. Additionally, the only record from the temperate northwest Atlantic Ocean attributed to this species cannot be assigned to B. tubernatis either. Therefore, a clarification about the current taxonomic status of B. tubernatis is provided and a short characterisation of the habitat of this species on the Portuguese coast is presented. As the occurrence of the species outside the northeast Atlantic Ocean is questioned, this work should renew the discussion about trans- and cis-Atlantic distributions of meiobenthic species.