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Systematic Criteria of the Eutardigrada
Abstract
Two orders are proposed: (1) Parachela, characterized by the absence of cephalic papillae and the presence of united primary and secondary branches of the double claw; and (2) Apochela with cephalic papillae and claws with the primary and secondary branches distinctly separate. New genera proposed are: (1) Dactylobiotus, distinguished from Macrobiotus Schultze by the absence of cuticular pores and by structurally connected double claws with no lunulae; (2) Minibiotus, separated from Macrobiotus by the absence of buccal lamellae and by a membrane enclosing processes of the egg; and (3) Pseudobiotus, distinguished from Isohypsibius Thulin by the presence of buccal lamellae and distinctive dorsal and ventral thickenings at the anterior end of the buccal tube. An arrangement of genera is derived from multicharacter analysis with emphasis on structures of the feeding apparatus. Systematic characters are illustrated by SEM photographs or line drawings, and a key is provided for the discrimination of eutardigrade genera.
... El tubo bucofaríngeo es una estructura compleja generalmente de forma cónica que cumple con un objetivo principal: la succión y procesamiento del alimento (Schuster et al.,1980;Nelson et al., 2015). ...
... En el extremo opuesto al anillo bucal se encuentra el bulbo faríngeo, cuya función es la fuerza de succión y procesamiento de comida. En casos específicos como en el orden Parachela de los Eutardígrados, este bulbo faríngeo presenta placoides, tanto de tamaño macro como micro, que ayudan a procesar la comida y a clasificar géneros y especies, no todos los órdenes presentan estas estructuras y existen excepciones en la conformación tanto de láminas peribucales como de macroplacoideas y microplacoideas ( Fig. 8; Schuster et al., 1980;Pilato & Blinda, 2010). ...
... Cutícula con poros de varios tamaños, número y distribución. Dos garras dobles de cada pata de tamaño similar y forma, lúnulas presentes (Schuster, Nelson, Grigarick & Christenberry, 1980). Observaciones: Color del cuerpo transparente, cutícula del cuerpo lisa sin papilas o protuberancias, longitud de 307 μm, con presencia de células fotorreceptoras, faringe con tubo bucal promedio de 41 μm, 10 lamelas, con dos macropalcoidas y ausencia de microplacoideas. ...
Este estudio examina la diversidad de tardígrados y briofitas en áreas semiurbanas de Ensenada, Baja California, México, mediante el muestreo en tres localidades: Chapultepec, Cañón Doña Petra y San Carlos. Se recolectaron un total de 52 muestras, de las cuales 65% fueron musgo, 29% de líquenes y 6% mixtas. Se identificarón 116 tardígrados, con una distribución significativa entre cuatro géneros: Macrobiotus (60%), Paramacrobiotus (38%), Milnesium (2%) y Echiniscus (1%). En la zona de Chapultepec, Paramacrobiotus richtersi dominó con el 60% de los especímenes, mientras que en Cañón Doña Petra y San Carlos, Macrobiotus hufelandi fue la especie predominante con 76% y 80%, respectivamente. Estos hallazgos destacan la capacidad de estas especies para adaptarse a ambientes con influencia antropogénica. El analisis de la diversidad mediante el índice de Shannon Weaver mostró que Chapultepec tenía la mayor diversidad de tardígrados, lo que sugiere la necesidad de más estudios para comprender mejor la distribución y ecología de estos organismos de la región. Este trabajo también documentó nuevos registros para Baja California, con la identificación de dos especies, Macrobiotus hufelandi y Paramacrobiotus richtersi y dos géneros, Echiniscus y Milnesium. Estos resultados contribuyen al conocimiento de la biodiversidad de tardígrados en la región, particularmente en zonas semiurbanas donde la actividad humana podría influir en su distribución.
... Since the second half of the past century, many new genera were described, deriving from species previously attributed to Macrobiotus; the today still valid of these genera are 12 or 13: Minibiotus Schuster, 1980in Schuster et al., 1980Dactylobiotus R.O. Schuster, 1980in Schuster et al., 1980Adorybiotus Maucci & Ramazzotti, 1981;Murrayon Bertolani & Pilato, 1988;Calcarobiotus Dastych, 1993;Xerobiotus Bertolani & Biserov, 1996 (its validity is still under debate); Schusterius Kaczmarek & Michalczyk, 2006;Paramacrobiotus Guidetti, Schill, Bertolani, Dandekar & Wolf, 2009;Tenuibiotus Pilato & Lisi, 2011;Diaforobiotus Guidetti et al., 2016;Mesobiotus Vecchi et al., 2016;Crenubiotus Lisi et al., 2020;Sisubiotus Stec et al., 2021. ...
... Since the second half of the past century, many new genera were described, deriving from species previously attributed to Macrobiotus; the today still valid of these genera are 12 or 13: Minibiotus Schuster, 1980in Schuster et al., 1980Dactylobiotus R.O. Schuster, 1980in Schuster et al., 1980Adorybiotus Maucci & Ramazzotti, 1981;Murrayon Bertolani & Pilato, 1988;Calcarobiotus Dastych, 1993;Xerobiotus Bertolani & Biserov, 1996 (its validity is still under debate); Schusterius Kaczmarek & Michalczyk, 2006;Paramacrobiotus Guidetti, Schill, Bertolani, Dandekar & Wolf, 2009;Tenuibiotus Pilato & Lisi, 2011;Diaforobiotus Guidetti et al., 2016;Mesobiotus Vecchi et al., 2016;Crenubiotus Lisi et al., 2020;Sisubiotus Stec et al., 2021. ...
... Since the second half of the past century, many new genera were described, deriving from species previously attributed to Macrobiotus; the today still valid of these genera are 12 or 13: Minibiotus Schuster, 1980in Schuster et al., 1980Dactylobiotus R.O. Schuster, 1980in Schuster et al., 1980Adorybiotus Maucci & Ramazzotti, 1981;Murrayon Bertolani & Pilato, 1988;Calcarobiotus Dastych, 1993;Xerobiotus Bertolani & Biserov, 1996 (its validity is still under debate); Schusterius Kaczmarek & Michalczyk, 2006;Paramacrobiotus Guidetti, Schill, Bertolani, Dandekar & Wolf, 2009;Tenuibiotus Pilato & Lisi, 2011;Diaforobiotus Guidetti et al., 2016;Mesobiotus Vecchi et al., 2016;Crenubiotus Lisi et al., 2020;Sisubiotus Stec et al., 2021. In spite of that, Macrobiotus still remains one of the richest genera of Tardigrada, and its (probable) monophyly has been claimed only very recently by Stec et al. (2021) after the separation of the genus Sisubiotus; before that, a polyphyly of the genus was largely assumed (e.g., Bertolani et al., 2014). ...
The authors identified a new species of the genus Macrobiotus during a revision of the Rocha-Doma tardigrade collection (National University of La Pampa, Argentina). New specimens from resampling were obtained, so that the new species, Macrobiotus olgae sp. nov., is integratively described using phase contrast microscope (PCM) material for morphology and morphometry, scanning electron microscope (SEM) material for very fine morphology, and DNA analysis. The new species has a slightly wrinkled cuticle with cuticular pores of two types and sizes (rounded/oval, smaller, and lenticular, bigger), oral cavity armature of the hufelandi type, and egg of the persimilis type. It belongs to the persimilis morphogroup and differs from all the other members of that group and the other congeneric species, by a unique combination of morphological and morphometric characters, and is also well differentiated genetically from all the other sequenced species. The discovery of Macrobiotus olgae sp. nov. confirms the importance of scientific collections and enriches the knowledge, today still limited, of the tardigrade fauna of Argentina and the whole Neotropical Region.
... Other traits contributed similarly to PC1 and PC2, except for process height, which contributed more to PC2 than PC1. Schuster, 1980(in Schuster et al. (1980) Dactylobiotus cf. octavi Material examined: Four animals and 50 eggs were extracted from the sample collected in Greenland. ...
... Other traits contributed similarly to PC1 and PC2, except for process height, which contributed more to PC2 than PC1. Schuster, 1980(in Schuster et al. (1980) Dactylobiotus cf. octavi Material examined: Four animals and 50 eggs were extracted from the sample collected in Greenland. ...
Two freshwater tardigrade populations belonging to the genus Dactylobiotus were investigated using phase contrast microscopy, scanning electron microscopy, and molecular markers commonly employed in tardigrade phylogenetic studies (18S rRNA, 28S rRNA, ITS2, and COI). The population from Taiwan, discovered through social media, represents a new species, described here as Dactylobiotus taiwanensis sp. nov. This species is most similar to Dactylobiotus parthenogeneticus but differs in the presence of singular rings of pores surrounding the egg processes and specific morphometric traits. The second population, from Greenland, was provisionally identified as D. cf. octavi, and its morphological discrepancies are discussed in detail. A revision of the type material for Dactylobiotus caldarellai and Dactylobiotus lombardoi raises questions about their validity due to insufficient data. Finally, a phylogenetic analysis incorporating taxa from the family Murrayidae, along with the newly sequenced populations, is presented. An updated dichotomous key for the genus Dactylobiotus is also provided.
... Currently, there are nearly 1500 described species in the phylum, which is divided into two classes: Heterotardigrada and Eutardigrada (Degma & Guidetti, 2009. Heterotardigrades encompass "armoured" (i.e. usually covered with thick dorsal plates) terrestrial and marine tardigrades that have a separate anus and gonopore (Kristensen, 1987;Fontoura et al., 2017), whereas eutardigrades group primarily "unarmoured" (i.e. usually covered with thin flexible cuticle) terrestrial and freshwater species that have a cloaca (Schuster et al., 1980). In contrast to more derived eutardigrades, heterotardigrades exhibit more characteristics that are closer to the ancestral morphotype. ...
Chaetotaxy (morphology and the arrangement of body appendages) and cuticular sculpturing provide key taxonomic traits in Echiniscidae, the most diverse limnoterrestrial heterotardigrade family. Historically, more attention was given to chaetotaxy, but with time cuticular sculpturing proved to bear a stronger phylogenetic signal. To date, two types of cuticular puncturing have been recognised: pseudopores (shallow exocuticular pits which appear in phase contrast microscopy, PCM, as blurred bright dots) and pores (canals that connect the environment with mesocuticular cavity network and which appear as sharp bright dots in PCM). In this study, we integratively describe Echiniscus quasiporus sp. nov. exhibiting a new type of cuticular puncturing, quasipores, which are deep cavities in exocuticle indistinguishable from pores neither under PCM nor via scanning electron microscopy (SEM) imaging of the cuticle surface, yet they do not connect the environment with mesocuticular cavity network. The morphology of quasipores became apparent only using a 3D analysis of cuticular structure in SEM. The new species was found in the Western Ghats of India, a global biodiversity hotspot, of which tardigrade fauna is extremely poorly known.
In this study, we present descriptions of two new eutardigrade species and additionally a detailed description of new population of Mesobiotus cf. coronatus discovered in the Cotacachi-Cayapas National Park in Ecuador. The presented analysis is based on morphological and morphometric data using light and scanning electron microscopy; description of Macrobiotus sharopovi sp. nov. and the population of Mesobiotus cf. coronatus were also supported with genetic data (nuclear barcode sequences, i.e., 18S rRNA, 28S rRNA and ITS-2, and one mitochondrial COI sequence). Based on the egg morphology, Mac. sharopovi sp. nov. belongs to Mac. paulinae morpho-group and is most similar to Mac. papei, Mac. paulinae, Mac. polypiformis and Mac. shonaicus but differs from them mainly by some characters of eggs (number of egg processes on circumference, details of eggshell morphology and features of filaments and their number) and adults (size of cuticular pores). Based on such features as the presence of gibbosities and well visible dorsal sculpture, the second new species, i.e., Ramazzottius syraxi sp. nov. is the most similar to Ram. baumanni species complex, Ram. belubellus, Ram. saltensis and Ram. szeptycki but differs from them by gibbosities configuration and morphology of dorsal sculpture. Mesobiotus cf. coronatus, which belongs to Meb. harmsworthi morpho-group, is potentially a new species but due to unclear taxonomic position of nominal Meb. coronatus, a formal description of this taxon is not possible in the present study.
Citation: Dmuchowska, W.; Nawrot, K.; Gawlak, M.; Warguła, J.; Kaczmarek, Ł. New Records of Tardigrades from the Republic of South Africa with Integrative Abstract: In this study, we provide a comprehensive description of a newly identified eutardigrade species, Mesobiotus longiconicus sp. nov., based on an integrative approach combining morphological and genetic data. The species was discovered at Lajuma Research Centre, Republic of South Africa, and is classified within the harmsworthi group. It can be differentiated from its closest relatives-Meb. barabanovi, Meb. ethiopicus, Meb. harmswor-thi, Meb. reinhardti, and Meb. skorackii-by distinct morphological and morphometric characteristics of the bucco-pharyngeal apparatus, claws, and eggs. These morphological differences are further validated by genetic analyses using four molecular markers: 28S rRNA, 18S rRNA, COI, and ITS2. Additionally, two other tardigrade species were identified in the same locality, including Minibiotus pentannulatus, which is now recorded for the second time outside its type locality. With this discovery, the total number of tardigrade taxa reported from South Africa reaches 101, including Meb. longiconicus sp. nov.
In this paper, we present an integrative description, utilizing morphological and genetic data, of a new eutardigrade species, Mesobiotus silesiacus sp. nov. The new species was discovered during research on Jasieniowa Mountain in Upper Silesia, Poland. While Mesobiotus silesiacus sp. nov. belongs to the harmsworthi group, it is distinguished from other group members i.e. and Mesobiotus wuzhishanensis Yin, Wang &Li, 2011 by several morphometric traits of the bucco-pharyngeal apparatus, claws, and/or eggs. The morphomet-ric findings are further supported by a comparative genetic analysis utilizing four molecular markers: 28S rRNA, 18S rRNA, COI and ITS2. Based on the compiled data, we also conducted a phylogenetic analysis using available genetic sequences of Mesobiotus representatives. The presented analysis clearly illustrates the position of the new species in the phylogenetic tree enabling also the discussion on the taxonomic composition and relatedness of other taxa within the genus Mesobiotus.
Over 250 years ago Johann August Ephraim Goeze, a Protestant pastor from Quedlinburg, Germany, discovered the first tardigrade. The German physiologist and anatomist Carl August Sigismund Schultze (1795–1877) later named the first species Macrobiotus hufelandi C.A.S. Schultze, 1834, a designation that remains valid today. By the first third of the twentieth century numerous new species had been discovered in Germany and were comprehensively compiled for the first time by the German zoologist Ernst Marcus in 1936. Since then additional faunistic studies have been conducted. This new checklist of tardigrades in Germany provides an overview of all known species found in the country to date. It includes 91 limno-terrestrial or limnic species and eight marine species, with 21 belonging to Heterotardigrada and 78 to Eutardigrada. Germany is the type locality (terra typica) for 24 tardigrade species. The number of identified tardigrade species varies significantly depending on the extent of studies conducted in different federal states. Baden-Württemberg has the highest number of species identified, with 80 species recorded across eleven studies. In this state the Black Forest, with its remarkable diversity of 72 identified tardigrade species is one of the most intensively studied regions worldwide. In Hesse 30 species have been recorded from five studies, while Berlin has documented 23 species from two studies. Fewer species have been reported from other federal states. The 99 tardigrade species identified in Germany represent about 7% of the total 1,488 described tardigrade species worldwide.
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