New species and records of tardigrades from a biological repository collection from the Sierra Nevada de Santa Marta, Colombia.

The Sierra Nevada de Santa Marta (SNSM) is a mountain range in northern Colombia, recognized for its high biological richness. To date, the existence of 27 species of tardigrades is known for this particular region. Morphological and morphometric analysis of 51 specimens, found in 16 samples of bryophytes and lichens collected at the SNSM, and deposited in the tardigrade collection of the "Centro de Colecciones Científicas de la Universidad del Magdalena" between 2011 and 2016 was carried out. The species Mixibius gibbosus sp. nov. is described based on the following main traits: presence of gibbosities (up to date never reported for any species of the genus Mixibius), isodiametric tubercles and relevant morphometric differences with respect to the most similar congeneric species. Additionally, the species Diphascon pingue pingue sensu lato, Hypsibius cf. allisoni and Adropion onorei are, for the first time, recorded for Colombia and the latter is recorded for the first time out of Ecuador. All records are new for the SNSM.

Two new tardigrade species (Echiniscidae and Doryphoribiidae) from the Salta province (Argentina).

Tardigrades from Argentina are poorly known. Two new species from the Salta province are described in the present contribution: Pseudechiniscus saltensis sp. nov., and Doryphoribius cephalogibbosus sp. nov. The former species belongs to the novaezeelandiae group and, apart from the nominal species of the group, it is similar to nine congeneric species by the following characters: the absence of spines on legs I and lateral papillae, the scapular plate with a transversal fold, the presence of projections at the posterior margin of the pseudosegmental plate, caudal plate not faceted, and cuticular ornamentation in the form of heads (capituli) of endocuticular pillars, protruding through epicuticle and joined by striae. However, the new species differs from all of them in important qualitative (e.g. colour, different division of plates, details of cuticular ornamentation, claws etc.) and morphometric characters. The new species exhibits a unique morphology of gonopore and anus. Doryphoribius cephalogibbosus sp. nov., by the presence of two macroplacoids, dorsal gibbosities, and inhabiting terrestrial environment, belongs to the flavus group and differs from all members of the group in having ten, instead of nine, rows of gibbosities (X:2-4-6- 6-6-6-6-4-2-2+2[LI-III]), with as a peculiar exclusive character, the presence of the two cephalic gibbosities, never reported in other Doryphoribius species. Moreover, the new species differs from the other species of the group by morphometric and more detailed morphological characters. The new species description also gave an occasion to discuss the issue of gibbosity arrangement in other species and address the morphology of claw accessory points.

Description of a new genus and species (Eutardigrada: Richtersiidae) from Colombia, with comments on the family Richtersiidae.

The new genus of the macrobiotoid family Richtersiidae Guidetti, Rebecchi, Bertolani, Jönsson, Kristensen Cesari, 2016 Crenubiotus gen. nov. is described, based on Crenubiotus crenulatus comb. nov. (Richters, 1904a) and on Colombian specimens formerly attributed to Macrobiotus cf. crenulatus and here described, after re-examination, as Crenubiotus revelator sp. nov. The new genus is characterised by an additional ventral thickening on the anterior portion of the ventral lamina, dorsal apophysis absent or very reduced, modified stylet furcae, claws equal in structure to those of Richtersius Pilato Binda, 1989, and very probably also Adorybiotus Maucci Ramazzotti, 1981 and Diaforobiotus Guidetti, Rebecchi, Bertolani, Jönsson, Kristensen Cesari, 2016; and, in the known species, cuticular pores, two macroplacoids, large well dentate lunules and a characteristic egg. The new species Crenubiotus revelator sp. nov. differs from Crenubiotus crenulatus comb. nov. in having smaller cuticular pores, a medio-ventral tooth in the buccal armature, more slender buccal tube, slightly more caudal stylet supports, slightly more slender claws, and in details of the egg. The description of the new genus, and new observations on Adorybiotus, Richtersius and Diaforobiotus, allowed the authors to complete the morphological scenario within the family Richtersiidae giving further support to such family.

Marine Tardigrada from the Mexican Caribbean with the description of Styraconyx robertoi sp. nov. (Arthrotardigrada: Styraconyxidae).

Marine tardigrades were sampled at three sites on Mexico's Caribbean coast. Eleven taxa were collected, one of which is described as a new species. Styraconyx robertoi sp. nov. is characterized by: asymmetric primary clavae; dorsal cuticle with a grid-like sculpture; claws with reduced accessory hooks; females with peduncles on only two digits (the external) of legs I-IV; males with peduncles only on the external digits of legs I-III and peduncles on all four digits of leg IV. Styraconyx robertoi sp. nov. is most similar to S. craticuliformis Chang Rho, 1998 and S. kristenseni Renaud-Mornant, 1981 by having asymmetric primary clavae but differs from S. craticuliformis mainly by the number of peduncles and from S. kristenseni mainly by the presence of a grid-like dorsal sculpture. Additionally, a comparison of material collected from the same region, but reported previously only as genus level records, was carried out in order to produce a refined list of the known Mexican marine tardigrade species.

Current knowledge on Mexican tardigrades with a description of Milnesium cassandrae sp. nov. (Eutardigrada: Milnesiidae) and discussion on the taxonomic value of dorsal pseudoplates in the genus Milnesium Doyère, 1840.

Mexico is a megadiverse country, however its tardigrade fauna is poorly known and to date 44 species have been reported from this region. In the present paper, an update of the reported Mexican tardigrades is presented, increasing the number of recorded tardigrades to 55 species (11 new records). Moreover, we describe Milnesium cassandrae sp. nov. from State of Nuevo León in northern Mexico. The new species is most similar to Mil. krzysztofi Kaczmarek Michalczyk, 2007 and Mil. beasleyi Kaczmarek, Jakubowska Michalczyk, 2012, but it differs from them mainly by details of the dorsal sculpture and some morphometric characters. We also discuss the taxonomic value of a recently described feature, 'pseudoplates', for differentiating the taxa within the genus Milnesium Doyère, 1840. [Zoobank URL: urn:lsid:zoobank.org:act:0684AE18-0510-4F7B-B75D-AE5177FBF2A2].

Two new species of Tardigrada from Ecuador (South America).

In two moss samples collected in El Cajas National Park (Azuay Province, Ecuador), 33 specimens and 19 eggs of a new species of Macrobiotus and 56 heterotardigrades belonging to a new Echiniscus species were extracted. Macrobiotus dulciporus sp. nov. belongs to the hufelandi group and is most similar to Macrobiotus maculatus Iharos, 1973. It differs from M. maculatus mainly based on the presence of an oral cavity armature of the patagonicus type, smooth egg chorion surface, lower number of processes on the egg circumference and some morphometric characters of the egg processes. Echiniscus hannae sp. nov. belongs to the bigranulatus group, but differs from all species in this group due to the presence of large, smooth areas on its dorsal plate.

A review of the Quaternary Scelidotheriinae (Mammalia, Xenarthra, Tardigrada) from the Tarija-Padcaya basin, Bolivia.

The Mylodontidae Scelidotheriinae (Mammalia, Xenarthra, Tardigrada) are a diversified clade of South American fossil ground sloths, with a wide geographic distribution, especially in high and middle latitudes. According to the last revision, the Quaternary diversity includes the genera Scelidotherium, Catonyx, and Valgipes. The clade Scelidotheriinae is well represented in the Pleistocene of the Tarija-Padcaya basin, and the first mention of these ground sloths correspond to the middle of the XIX Century. Since then, several species (i.e., Scelidotherium tarijensis, Scelidodon tarijensis, Scelidotherium capellini) have been reported as inhabiting the Tarija-Padcaya basin during the Pleistocene. Despite the abundance of fossil records of Scelidotheriinae in this area, no modern taxonomic revisions are available. In consequence, in this contribution a revision of the remains assigned to Scelidotheriinae from the Tarija-Padcaya basin is accomplished, and some biostratigraphic and geographic implications are discussed. Our results show that one single species (Catonyx tarijensis) can be recognized in the studied area, whereas a supposed smaller one (Scelidotherium patrium) actually corresponds to juvenile specimens of C. tarijensis.

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.

An integrative description of a new tardigrade species Mesobiotus romani sp. nov. (Macrobiotidae: harmsworthi group) from the Ecuadorian Pacific coast.

In a mixed moss and lichen sample collected in Esmeraldas Province in north-western Ecuador, 20 tardigrades and 11 eggs, belonging to a new species of the genus Mesobiotus, were found. In addition to the traditional taxonomic description with morphometrics, light and scanning microscopy imaging, we also provide nucleotide sequences of three nuclear (18S rRNA, 28S rRNA, ITS-2) and one mitochondrial (COI) DNA fragments of the new species. Based on the egg chorion morphology, Mesobiotus romani sp. nov. is the most similar to: M. binieki, M. coronatus, M. dimentmani, M. patiens, M. perfidus, M. philippinicusi, M. pseudoblocki, M. pseudocoronatus, M. pseudopatiens, M. radiatus, M. rigidus, M. simulans and M. wuzhishanensis, but differs mainly by some specific characters of both egg and adult morphology, and morphometrics.

A closer look at Batillipes dicrocercus and new records of Batillipes potiguarensis (Tardigrada: Arthrotardigrada) from the Brazilian coast with comments on intra- and interspecific variability / Considerações sobre Batillipes dicrocercus e novos registros de Batillipes potiguarensis (Tardigrada: Arthrotardigrada) da costa brasileira, com foco na variabilidade intra- e interespecífica

Batillipes specimens collected in the Southwestern Atlantic Ocean, on the Brazilian Coast (Campos Basin and Potiguar Basin) with a bifurcated caudal appendage similar to B. dicrocercus Pollock, 1970 were assigned to B. potiguarensis Santos, da Rocha, Gomes Jr & Fontoura, 2017. This species was described as having a roundish caudal protrusion but, as shown in this study, it exhibits intraspecific variability of the morphology of the caudal apparatus. The examination of specimens of B. dicrocercus from the type locality (Massachussetts, U.S.A.) and the analysis of the original description and two subsequent emended descriptions, one from the Gulf of Mexico (U.S.A.) and another from the Mediterranean Sea, used for comparison, revealed important differences among them concerning important taxonomic characters, suggesting that what was considered a single species should now be split into three different species. Therefore, an emended diagnosis of B. potiguarensis and comments on the geographic distribution of B. dicrocercus are provided, clarifying the taxonomic status of the two species.

Exemplares do gênero Batillipes provenientes do sudoeste do Oceano Atlântico na Costa Brasileira (Bacia de Campos e Bacia Potiguar), apresentando um apêndice caudal bifurcado muito semelhante ao de B. dicrocercus Pollock, 1970, foram identificados como pertencendo a B. potiguarensis Santos, da Rocha, Gomes Jr & Fontoura, 2017, uma espécie caracterizada por exibir uma protrusão caudal arredondada. A identificação baseou-se, como demonstrado neste estudo, que em B. potiguarensis a morfologia do aparato caudal apresenta variabilidade intraespecífica. O exame de exemplares de B. dicrocercus da localidade-tipo (Massachussetts, E.U.A.) e a análise da descrição original e duas descrições subsequentes, uma baseada em exemplares do Golfo do México (U.S.A.) e outra em exemplares do Mar Mediterrâneo, efetuadas para comparação, revelou diferenças importantes no que diz respeito a caracteres taxonômicos relevantes. Este resultado sugere que aquelas descrições correspondem não a uma, mas sim a três espécies distintas. Assim, neste trabalho, completa-se a diagnose de B. potiguarensis e tecem-se comentários sobre a distribuição geográfica de B. dicrocercus, contribuindo para contribuindo para o esclarecimento do status taxonômico destas espécies.

A closer look at Batillipes dicrocercus and new records of Batillipes potiguarensis (Tardigrada: Arthrotardigrada) from the Brazilian coast with comments on intra- and interspecific variability / Considerações sobre Batillipes dicrocercus e novos registros de Batillipes potiguarensis (Tardigrada: Arthrotardigrada) da costa brasileira, com foco na variabilidade intra- e interespecífica

Batillipes specimens collected in the Southwestern Atlantic Ocean, on the Brazilian Coast (Campos Basin and Potiguar Basin) with a bifurcated caudal appendage similar to B. dicrocercus Pollock, 1970 were assigned to B. potiguarensis Santos, da Rocha, Gomes Jr & Fontoura, 2017. This species was described as having a roundish caudal protrusion but, as shown in this study, it exhibits intraspecific variability of the morphology of the caudal apparatus. The examination of specimens of B. dicrocercus from the type locality (Massachussetts, U.S.A.) and the analysis of the original description and two subsequent emended descriptions, one from the Gulf of Mexico (U.S.A.) and another from the Mediterranean Sea, used for comparison, revealed important differences among them concerning important taxonomic characters, suggesting that what was considered a single species should now be split into three different species. Therefore, an emended diagnosis of B. potiguarensis and comments on the geographic distribution of B. dicrocercus are provided, clarifying the taxonomic status of the two species.(AU)

Exemplares do gênero Batillipes provenientes do sudoeste do Oceano Atlântico na Costa Brasileira (Bacia de Campos e Bacia Potiguar), apresentando um apêndice caudal bifurcado muito semelhante ao de B. dicrocercus Pollock, 1970, foram identificados como pertencendo a B. potiguarensis Santos, da Rocha, Gomes Jr & Fontoura, 2017, uma espécie caracterizada por exibir uma protrusão caudal arredondada. A identificação baseou-se, como demonstrado neste estudo, que em B. potiguarensis a morfologia do aparato caudal apresenta variabilidade intraespecífica. O exame de exemplares de B. dicrocercus da localidade-tipo (Massachussetts, E.U.A.) e a análise da descrição original e duas descrições subsequentes, uma baseada em exemplares do Golfo do México (U.S.A.) e outra em exemplares do Mar Mediterrâneo, efetuadas para comparação, revelou diferenças importantes no que diz respeito a caracteres taxonômicos relevantes. Este resultado sugere que aquelas descrições correspondem não a uma, mas sim a três espécies distintas. Assim, neste trabalho, completa-se a diagnose de B. potiguarensis e tecem-se comentários sobre a distribuição geográfica de B. dicrocercus, contribuindo para contribuindo para o esclarecimento do status taxonômico destas espécies.(AU)

A description of Macrobiotus horningi sp. nov. and redescriptions of M. maculatus comb. nov. Iharos, 1973 and M. rawsoni Horning et al., 1978 (Tardigrada: Eutardigrada: Macrobiotidae: hufelandi group).

We examined microscope slides from Horning and Iharos tardigrade collections from Museum of New Zealand Te Papa Tongarewa in Wellington and Hungarian Natural History Museum in Budapest with species of the Macrobiotus hufelandi group. Based on this material we describe one new species, Macrobiotus horningi sp. nov., and re-describe two others, M. maculatus comb. nov. Iharos, 1973 and M. rawsoni Horning et al., 1978. With the oral cavity armature of the patagonicus type and chorion of the hufelandi type, Macrobiotus horningi sp. nov. is most similar to: M. personatus Biserov, 1990, M. sandrae Bertolani & Rebecchi, 1993, M. serratus Bertolani et al., 1996, M. sottilei Pilato et al., 2012, M. terminalis Bertolani & Rebecchi, 1993 and M. vladimiri Bertolani et al., 2011, but it differs from them in morphological and morphometric traits. With eggs of the maculatus type, M. maculatus comb. nov. is most similar to: M. biserovi Bertolani et al., 1996, M. denticulatus Dastych, 2002, M. macrocalix Bertolani & Rebecchi, 1993 and M. ramoli Dastych, 2005, but differs from them in morphological and morphometric characters.

The Macrobiotus hufelandi group (Tardigrada) revisited.

Species of the Macrobiotus hufelandi group are one of the most often recorded tardigrades throughout the globe. For over a century M. hufelandi has been considered cosmopolitan but in recent decades numerous species of similar morphologies have been described from various continents, which suggests that what was originally defined as a single taxon is, in fact, a complex of species. The definition of the hufelandi group is subject to a long-standing discussion and in this paper we propose a refined set of characters that are hoped to elucidate the taxonomic status of the group. In order to aid interspecific comparisons, we also propose a unified nomenclature for the crucial morphological traits and clar.

New records of tardigrades from Colombia with the description of Paramacrobiotus sagani sp. nov. and Doryphoribius rosanae sp. nov.

By examining material collected in the Sierra Nevada de Santa Marta (Department of Magdalena, Colombia), the authors report a new record for the entire South America, Doryphoribius gibber Beasley & Pilato, 1987, and two species new to science, Paramacrobiotus sagani sp. nov., and Doryphoribius rosane sp. nov., are described. Paramacrobiotus sagani sp. nov. belongs to the richtersi group, vanescens subgroup (by having sculptured egg areolae) and is characterized by a peculiar cuticular granulation, trunco-conical egg processes with cylindrical indented apices, and other more detailed cha-racters both qualitative and metric; by the unique combination of characters, it differs from all the other known species of the genus. Doryphoribius rosanae sp. nov. is characterized by reticulated dorsal cuticle with gibbosities (formula IX:4-6-2-6-2-6-4-2-2), two macroplacoids in the pharynx without microplacoid or septulum, and large, stout claws without "free" accessory points but with lunules. It differs from all the other Doryphoribius species with gibbosities by having a unique formula, as well as other more detailed characters. Thanks to this contribution, the number of tardigrade species known for Colombia increases from 52 to 55.

Doryphoribius chetumalensis sp. nov. (Eutardigrada: Isohypsibiidae) a new tardigrade species discovered in an unusual habitat of urban areas of Mexico.

A new species, Doryphoribius chetumalensis, is described from specimens collected in the city of Chetumal (Quintana Roo state, Mexico). The species was found in a new and unusual habitat for urban tardigrades, i.e. the soil sediment accumulated on the border of streets. This discovery shows that tardigrades can live in this habitat, demonstrating once again the wide capacity of this taxon to tolerate adverse habitats, and to survive in environments with high anthropogenic impact. Doryphoribius chetumalensis sp. nov. differs from all the other species of the genus in having enlarged and wide bulbous base of the claws. Within Doryphoribius, it belongs to the zappalai group, and differs from the species in this group, not only in the claw shape, but also by the orange body colour, the smooth cuticle, the absence of a tooth in the wall of the buccal ring, and the absence of lunules under the claws. This is the first record of tardigrades, identified to species level, in Quintana Roo state. A taxonomic key of the Doryphoribius genus is also presented.

Three new Batillipes species (Arthrotardigrada: Batillipedidae) from the Brazilian coast.

Three new tardigrade species, Batillipes brasiliensis sp. nov., Batillipes dandarae sp. nov. and Batillipes potiguarensis sp. nov., are described from shallow subtidal sediments of the Brazilian coast. B. brasiliensis sp. nov. and B. dandarae sp. nov. have toes 3 and 4 on leg IV different in length, so they can be included in the D group of species, while B. potiguarensis sp. nov., with toes 3 and 4 on leg IV equal in length belong to the A group. Batillipes brasiliensis sp. nov. is characterized by having an ala-like caudal expansion; cuticular projections on the coxal region of legs I-III, and lateral projections. The lateral projection located between the third and fourth legs is fringed with digit-shaped expansions. Batillipes dandarae sp. nov. has a dorsal blunt enlargement in the scapular region; a pointed triangular caudal appendage, and no lateral projections. The new species exhibits a sensorial spine on legs I inserted posteriorly and turning forward, and anus surrounded by a peculiar cuticular structure constituted by six platelets. Batillipes potiguarensis sp. nov. is characterized by a unique combination of characters: scapular region well developed, protruding laterally at the level of the first pair of legs; lateral blunt processes between legs, and prominent roundish caudal protrusion. In addition, the new species exhibits cephalic appendages with swollen tips, evident secondary clavae, and very short sense organs on the legs IV.

Annotated zoogeography of non-marine Tardigrada. Part III: North America and Greenland.

This paper is the third monograph of the series that describes the global records of limno-terrestrial water bears (Tardigrada). Here, we provide a comprehensive list of non-marine tardigrades recorded from the North America, providing an updated and revised taxonomy accompanied by geographic co-ordinates, habitat, and biogeographic comments. It is hoped this work will serve as a reference point and background for further zoogeographical and taxonomical studies.

Tardigrades from Nahuel Huapi National Park (Argentina, South America) with descriptions of two new Macrobiotidae species.

In 31 samples of mosses and lichens collected in the Argentinean province of Río Negro, 657 tardigrades, 53 exuviae and 219 free-laid eggs were found. In total, 20 species were identified: Diphascon chilenense, Dip. mitrense, Echiniscus bigranulatus, Ech. corrugicaudatus, Ech. merokensis merokensis, Ech. testudo, Hebesuncus mollispinus, Hypsibius convergens, Macrobiotus cf. anderssoni, Mac. andinus, Mac. kazmierskii, Mac. patagonicus, Mesobiotus szeptyckii, Mes. pseudoblocki sp. nov., Milnesium argentinum, Mil. beatae, Mil. brachyungue, Mil. granulatum, Mopsechiniscus granulosus, Minibiotus pseudostellarus sp. nov. Of the two new species, Mesobiotus pseudoblocki sp. nov. is most similar to Mes. blocki, but it differs mainly by the lack of dentate lunules, smaller eggs and presence of reticular design on egg processes. Minibiotus pseudostellarus sp. nov. is most similar to Min. constellatus, Min. eichhorni, Min. sidereus or Min. vinciguerrae, but it differs from them by the presence of 'pseudo-star'-shaped pores in the dorsal cuticle instead of fully developed 'stars' and by other morphometric characters.

Evaluación de la diversidad en comunidades de tardígrados (Ecdysozoa: Tardigrada) en hábitats urbano y rural de la ciudad de Salta (Argentina) / Diversity assessment in tardigrades communities (Ecdysozoa, Tardigrada) in urban and rural habitats of the city of Salta (Argentina)

Este trabajo se realizó bajo la hipótesis de que existe una pérdida creciente de diversidad en las comunidades de tardígrados, desde las áreas rurales hacia las urbanas, incrementando la homogenización de sus comunidades producto de la urbanización. Para la ciudad de Salta, se tomaron muestras en áreas con tránsito vehicular alto y muestras en áreas rurales circundantes. Se identificaron en total ocho especies/morfoespecies. El inventario tuvo una completitud mayor al 94%. La comunidad rural fue más diversa y estructuralmente más uniforme que la comunidad urbana. Macrobiotus hufelandi Schultze, 1834 resultó especie indicadora y Milnesium sp. como detectora para el hábitat urbano, mientras que Paramacrobiotus areolatus Murray, 1907 resultó indicadora para el hábitat rural.

This work was carried out under the hypothesis that there is a growing loss of diversity in communities of tardigrades, from rural to urban areas, increasing the homogenization of its communities due to the urbanization. Samples were taken from the city of Salta in areas with high vehicular traffic and samples in surrounding rural areas. We identified a total of eight species/morphospecies. The inventory completeness was greater than 94%. The rural community was more diverse and structurally more uniform compared with the urban one, shown that both communities were different. Macrobiotus hufelandi Schultze, 1834 results as an indicator species, and Milnesium sp. as detector species from urban habitat; meanwhile Paramacrobiotus areolatus Murray 1907 was an indicator species for rural areas.