Adhesive Tubes Research Articles

A new species of Crasiella (Gastrotricha: Planodasyidae) from Capron Shoal, Florida, USA.

A new gastrotrich species of the genus Crasiella (Macrodasyida: Planodasyidae) is described from Capron Shoal, Florida, USA. The new species is up to 520 μm long and differs from its congeners in the position of adhesive tubes and the structure of its spermatozoa. There are nine TbA that insert ventrally on the head plus an additional pair of TBA that insert medially. Up to 42 TbVL per side. Six pairs of TbP insert on a pair of caudal pedicles. Animals are simultaneous hermaphrodites with an elongated frontal organ and large caudal organ. The spermatozoa have a tripartite acrosome unlike others in the genus that have a four-part acrosome.

Discovery of two ‘chimeric’ Gastrotricha and their systematic placement based on an integrative approach

AbstractSublittoral sand from the islands of Sardinia (Italy) and Flores (Azores) – separated by more than 3700 km linear distance and 8 years between two independent sampling campaigns – yielded conspicuous specimens of two bizarre, yet undescribed, species of the marine gastrotrich clade Macrodasyida. These gastrotrichs combine several character traits that were already known from two, non-related genera. Morphological data were carefully analysed and digitally documented, and nuclear and mitochondrial DNA sequences were used for phylogenetic inference. The results of these analyses claim for the erection of a new genus. Specimens of the new taxon have a body length of less than 400 µm and are characterized by a wide, funnel-shaped mouth opening shielded dorsally by an oral hood and possess a posterior peduncle that ends with a Y-shaped pair of appendages that carry the posterior adhesive tubes. Further tubes occur as anterior, ventrolateral and lateral series; the gonads are unpaired and there is a set of two accessory reproductive organs. Molecular phylogenetic analyses confirm the results of former studies and clearly place the new taxon in Thaumastodermatidae. We hereby propose the establishment of Chimaeradasys gen. nov. and describe C. oligotubulatus sp. nov. from the Azores and C. polytubulatus sp. nov. from Sardinia.

Echinoderes vulcanicus sp. nov. from the active marine volcano Piip – the first representative of the Kinorhyncha in the Bering Sea (Kinorhyncha: Cyclorhagida)

A new species of echinoderid kinorhynchs, Echinoderes vulcanicus sp. nov. collected from detritus washed off deep-water sponges collected at the slope of active marine volcano Piip in the Bering Sea, North-West Pacific, is described and illustrated using light and scanning electron microscopy. This new representative of Echinoderes, the most specious kinorhynch genus, is characterized by a unique set of characters and is easily distinguished from the other congeners. This species is well recognized by the structure of the terminal segment having large, broadly rounded sternal plates prominently extending beyond shorter tergal extensions. Both sternal and tergal plates of this segment have prominent terminal fringe with long and thick tips. The second trunk segment bears a pair of adhesive tubes; trunk segment 5 with pair of tubes in lateroventral position; acicular lateroventral spines on trunk segments 6–9; acicular middorsal spines on trunk segments 4–8; trunk segment 10 with pair of tubules in lateroventral position; males possess three pairs of penile spines. E. vulcanicus sp. nov. constitutes the first kinorhynch species found at the top of the active marine volcano and the first representative of the Kinorhyncha in the Bering Sea.

New Chaetonotus (Wolterecka. Semovitus sp. nov. (Gastrotricha: Chaetonotida: Chaetonotidae) from a Palm House in Vienna (Austria)

Gastrotricha is a monophyletic phylum of small invertebrates inhabiting any kind of aquatic and semi-aquatic environments. Currently, ca. 850 gastrotrich species have been described, although the species numbers are not evenly distributed among the families and genera. The family Chaetonotidae Gosse, 1864 (sensuLeasi & Todaro, 2008) is considered the most numerous and diverse, with the most abundant genus being ChaetonotusEhrenberg, 1830. This genus has more species grouped together than all of the remaining genera of this family. Nevertheless, when the subgenera division within Chaetonotus is analysed it is noticeable that the differences in species number are also very large among these groups. One of the smallest and rarest is the subgenus WoltereckaMola, 1932, which currently includes only three nominal species. The main characteristics of this subgenus are short, reduced hook-shaped adhesive tubes and long, rigid spines on dorsal or dorsolateral surfaces of the furcal base and furcal appendages. In this paper, a new representative of Wolterecka is described, namely Chaetonotus (W.) semovitussp. nov. This taxon was found in the Schonbrunn Palm House in Vienna (Austria) and is distinguished from the other Chaetonotus (Wolterecka) species mainly by the presence of three pairs of cephalic cilia, a seven-lobed head outline and scales with a concave posterior edge and diversified shape around the body. For this new species, detailed morphological and molecular analyses including 18S rRNA, ITS1–5.8S rRNA–ITS2, 28S rRNA and COI mtDNA are presented.

Integrative morphological and molecular investigation of Turbanella hyalina Schultze, 1853 (Gastrotricha: Macrodasyida), including a redescription of the species

Early descriptions of Gastrotricha mostly lack information that is nowadays essential for a reliable diagnosis and determination of species. This deficiency covers data on taxonomically important external characters (e.g., scale patterns, collocation of cilia, number and arrangement of adhesive tubes) and/or internal features (e.g., anatomy of reproductive organs). Furthermore, the morphological variability is often not or insufficiently documented. Holding a reliable knowledge about the latter is more relevant than ever before, since the discovery of morphologically cryptic genetic meiofauna species is increasing. It is especially a robust morphometry, amongst other relevant data such as ecology and behaviour, that can yield further evidence supporting or disproving the respective species hypothesis. The marine gastrotrich Turbanella hyalina Schultze, 1853 was the first described species of the whole subclade Macrodasyida but data that have been specified above were mostly missing. This repeatedly caused taxonomic confusion with other congeneric species in the past. Furthermore, a considerable amount of intraspecific genetic diversity was recently discovered among different European populations of T. hyalina as well as evidence for the presence of two cryptic species. In order to reduce deficiency and to warrant a reliable identification of T. hyalina in the future, we have conducted an integrative investigation of specimens of the type locality covering a survey of the morphological variability, an analysis of mtDNA sequence data (COI), and a reconstruction of the muscular system based on confocal microscopy. The latter was included because in the recent past, a hidden species diversity of another marine gastrotrich taxon was discovered due to differences in the muscular system between two geographically separated ‘populations’.While morphometric and meristic variation of T. hyalina broadly overlaps with other congeneric species, our light and electron microscope data bore the presence of up to twelve pairs of reduced ventral adhesive tubes on the posterior trunk section, possibly an autapomorphic and hence diagnostic character of T. hyalina. Furthermore, we were able to prove the absence of a pair of ventral ‘cirrata tubes’ that is present in similar species of the genus. The myoanatomy exhibits several similarities but also distinct differences compared to other con-generic species. Our mtDNA survey uncovered more intraspecific genetic diversity than previously known. However, the data also demonstrate that populations of different northwest European sites belong to the same species. The observed phylogeographic patterns are possibly related to post-glacial population expansions in the studied area and may already demonstrate a certain restriction of the gene flow.

Three-Dimensional HyCoSy With Perfluoropropane-Albumin Microspheres as Contrast Agents and Normal Saline Injections Into the Pelvic Cavity for Morphological Assessment of the Fallopian Tube in Infertile Women.

To apply the three-dimensional (3D) hysterosalpingo-contrast sonography (HyCoSy) with perfluoropropane-albumin microspheres as contrast agents and normal saline injections into the pelvic cavity for assessment of the tubal patency and adhesions of fimbrial parts. Fifty-five infertile female patients were recruited to undergo 3D HyCoSy with normal saline injected into the pelvic cavity, in which the tubal patency was observed by visualizing the spillage of contrast agents from the fimbriae, and the fimbrial adhesion was confirmed by the finger-like projections of the fimbriae and their floating and moving status. Of the 55 patients, bilateral tubal patency was observed in 44 (80.0%), unilateral tubal patency and the other partial occlusion in 7 (12.7%), unilateral partial occlusion and the other complete occlusion in 3 (5.4%), and bilateral complete occlusion in 1 (1.8%). The fimbrial parts were observed in 105 fallopian tubes, among which 101 were seen with the finger-like fimbriae floated and moved in the pelvic cavity, whereas 4 tubes were not because of adhesion to the pelvic cavity (n = 3) or the ovary and intestine (n = 1). More than three visible, quite long, and distributed evenly finger-like projections were present for the patent fimbrial parts; however, fewer, flat, and not evenly distributed finger-like projections were present for the adhesive tubes. No serious complications occurred during or after this procedure. Combination of 3D HyCoSy with normal saline injected into the pelvic cavity may be a feasible and safe procedure to assess tubal patency and adhesions of the fimbrial parts.

Description of a new species ofThaumastoderma(Gastrotricha: Macrodasyida: Thaumastodermatidae) from Belize and Tobago

Abstract A new species of Thaumastoderma (Gastrotricha: Macrodasyida: Thaumastodermatidae) is described from sublittoral sediments on the islands of Tobago (Trinidad and Tobago) and Carrie Bow Cay (Belize). Thaumastoderma ponticulus sp. nov. is similar to Th. ramuliferum and Th. cantacuzeni based on the presence of four pairs of dorsal cirrata tubes and a compound pair of spatulate tentacles. The main distinguishing characteristic is the presence of a fleshy bridge that interconnects the anterior and posterior spatulate tentacles on the head. Additional characters include the presence of two rows of anterior adhesive tubes, seven pairs of ventrolateral adhesive tubes, and five pairs of posterior adhesive tubes.

A new species of the genusTetranchyroderma(Gastrotricha: Macrodasyida: Thaumastodermatidae) from Korea, with a peculiar pentancrous armature

Abstract. Surveys of marine gastrotrichs on the coast of South Korea yielded a new species of the genus Tetranchyroderma, bearing 5-pronged hooks as a cuticular armature. Tetranchyroderma hummoni is characterized by a dorsal armature adorned with pentancres, whose central tines are about twice as long as peripheral tines. The new species is also characterized by bearing 3 large and broad papillae per side along boundary row of pentancres on oral hood, a pair of rod-like cephalic tentacles, and a pair of modified pestle organs. Moreover, this new species is clearly distinguished from its congeners by the number of dorsal, dorsolateral and ventrolateral cirratum-type tubes (6−10, 13−19, and 9−14 per side, respectively), and by a pair of foot-like ventral adhesive tubes. The description of the new species belonging to the genus Tetranchyroderma is based on detailed illustrations and scanning electron microscopy. We also provide a short account on the variability within the species, including the morphologica...

A new genus and new species of freshwater Chaetonotidae (Gastrotricha: Chaetonotida) from Brazil with phylogenetic position inferred from nuclear and mitochondrial DNA sequences

Most studies of South American freshwater Gastrotricha have focused on the inland waters of Brazil including São Paulo State, Mato Grosso do Sul State, and Pará State. In this paper, we describe a new genus and species, Cephalionotus kisielewskii gen. et. sp. nov. (Chaetonotida, Chaetonotidae), from Minas Gerais State using morphological data and DNA sequence data (18S rDNA and COI genes). The new genus contains a single psammic species collected from high altitude streams. Cephalionotus gen. nov. exhibits a set of autapomorphic characters that easily distinguish it from all other genera of Chaetonotida: extremely large cephalion and hypostomium that completely cover the dorsal and ventral sides of the head, respectively; a single pair of pleurae; peculiar shape and arrangement of dorsal and ventral scales in the posterior trunk region; one paired, very large, keeled scale at the ventral posterior end; and very long adhesive tubes divided into three parts. Affinity of Cephalionotus kisielewskii gen. et sp. nov. with other Chaetonotida (Paucitubulatina) is discussed from morphological and molecular perspectives.http://zoobank.org/urn:lsid:zoobank.org:pub:5E324696-AB33-42C2-A27A-609B1983D540

Two known and one new species of Draconematidae and Epsilonematida(Nematoda, Desmodorida) from the White Sea, North Russia.

Morphological descriptions of three "walking nematode" species found for the first time in the White Sea are presented. Draconema ophicephalum (Claparède, 1863) (Draconematidae) and Epsilonema steineri Chitwood, 1935 (Epsilonematidae), both known from insufficient material and females only, are re-described and problems of their taxonomic identification as well as species compositions of respective genera are discussed. The new species Prochaetosoma marisalbi sp. n. (Draconematidae) differs from other Prochaetosoma species except P. longicapitatum (Allgén, 1935) in that the pharyngeal bulb lumen is not cuticularised, from P. longicapitatum by shape of body and rostrum, greater number of cephalic adhesive tubes, and from P. maertensi Decraemer, 1989 by having a relatively longer tail, fewer anterior adhesive tubes and longer spicules, besides lacking cuticular thickening in the pharyngeal bulb. Draconema hoonsooi, D. youngeouni, P.rochaetosoma beomseomense, P. brevicaudatum, P. byungilli, P. cracense, P. saheungi, P. sujungi, P. supseomense erected by Rho & Min (2011) are considered as invalid species while Prochaetosoma arcticum, P. lugubre and Epsilonema cygnoides are assumed as species inquirenda. From a phylogenetic tree based on the 18S rRNA gene, all three White Sea species adjoin to unidentified species of their respective genera.

First description of a gastrotrich with four scale types, including feathered biancres, a novel find for Gastrotricha

A new species of Tetranchyroderma, T. garraffonii, is described from sublittoral sediments off the coast of Florida, USA. The new species possesses mixed scale types in the form of feathered biancres – a novel discovery for the genus – as well as feathered triancres and ordinary triancres. Biancres consist of a round scale base, a pair of ancre shafts that arise individually from a v-shaped cuticular ridge on the scale, and feathered ancres. Triancres are similar in appearance but have a different ridge pattern. Ordinary triancres occurred in two forms on the lateral sides of the body: a bowl-shaped ancre and a ‘pitchfork’ shaped ancre. Other distinguishing characteristics of the new species include the presence of cephalic tentacles, a papillated fringe to the oral hood, and a single pair of lateral and dorsolateral adhesive tubes at the posterior end. Confocal microscopy verified the presence of a muscular caudal organ and partly muscular vas deferens.

First record and a description of a new species ofOregodasys(Gastrotricha: Macrodasyida: Thaumastodermatidae) from Tobago

Abstract A new species of Oregodasys (Gastrotricha: Macrodasyida: Thaumastodermatidae) is described from sublittoral sediments on the island of Tobago. Oregodasys ashleigha sp. nov. is 430–465 μm long and characterized by the presence of a pair of large and elliptical red ocelli, numerous cirri (21–23) restricted to the posterior end, and an inflated, bilobed caudum. Adhesive tubes are present in four series as TbA (10/side), TbL (10/side), TbVL (up to 45/side), and TbP (up to 51 total). The structure of the reproductive system is characteristic of the genus and defined by posterior ovaries, a single right testis, a bipartite caudal organ complex, and a frontal organ. The bipartite caudal organ complex is distinctly muscular, with the right-side caudal organ wrapped in spiral muscles and the left-center side caudal organ wrapped in circular muscles.

The phylogenetic position of Neogosseidae (Gastrotricha: Chaetonotida) and the origin of planktonic Gastrotricha

Planktonic forms of Gastrotricha have been known since the 1850s, despite the fact that they are rather uncommon and difficult to collect. They are characterized by a round sack-shaped body, an absence of furcal adhesive tubes, and a different distribution of the locomotory ciliation compared to epibenthic and periphytic gastrotrichs. Today, planktonic gastrotrichs are classified into the three taxa—Dasydytidae, Neogosseidae, and Undula—but their origin and whether they share a recent common ancestor remain largely unknown. A long-held view is that planktonic taxa are derived from benthic ancestors related to Chaetonotus (Zonochaeta), but the hypothesis has never been properly tested. Here, in order to elucidate the phylogeny and origin of planktonic Gastrotricha, we provide the first molecular data on the very rare genera Kijanebalola and Neogossea, both members of the family Neogosseidae. We use Bayesian and maximum likelihood phylogenetics to analyze sequences of 18S rDNA, 28S rDNA, and COI mtDNA spanning 71 taxa in total. We find high support for a common origin of planktonic gastrotrichs, with monophyly of both Dasydytidae and Neogosseidae. Planktonic forms have evolved from epibenthic or periphytic ancestors, and the closest extant clade comprises members of Chaetonotus (Zonochaeta) + Chaetonotus heteracanthus Remane, 1927. These results further imply that the motile spines and underlying muscle patterns that control them in species of Dasydytidae are adaptations to the planktonic environment that evolved independently of those in other species of Gastrotricha.

A new species of Cephalodasys (Gastrotricha, Macrodasyida) from the Caribbean Sea with a determination key to species of the genus.

A new marine gastrotrich species of the genus Cephalodasys is described from shallow sublittoral coralline sand sampled between Lee Stocking Island and Norman's Pond Cay (Exuma Cays), Bahamas. Cephalodasys interinsularis n. sp. reaches a body length of 471 µm and is characterized by a new combination of characters including six total anterior adhesive tubes and five pairs of ventrolateral adhesive tubes. The new species is morphologically similar to C. swedmarki but can be distinguished by the different number of anterior adhesive tubes, the spatial arrangement of the ventrolateral adhesive tubes, and a shorter pharynx. We provide an updated diagnosis of the genus and a determination key to all known species of Cephalodasys. C. interinsularis n. sp. is the third known species of Cephalodasys from the Caribbean marine province.

Two new marine Gastrotricha from the Indian Ocean coast of South Africa.

The study is part of a larger research programme aimed at shedding light on the gastrotrich communities of the subtropical east coast province of KwaZulu-Natal, South Africa. In previous papers, faunistic and preliminary taxonomic data on marine and freshwater gastrotrichs found in the iSimangaliso Wetland Park, were reported. Here two new interesting marine macrodasyidan species in the families Dactylopodolidae and Thaumastodermatidae are described based on observations carried out on living specimens and using differential interference contrast microscopy. The two novel species are named in honor of two great South African icons recently deceased: Nadine Gordimer and Nelson Mandela. Dactylopodola nadine sp. n. is the third species in the genus to bear red eye-spots; it can easily be distinguished from the closely-related red-eyed D. baltica and D. roscovita by its smaller size (Total length = 230 μm vs 275 μm vs 450 μm, respectively) and the lower number of adhesive tubes of the anterior, lateral and posterior series (on each side: 3, 4 and 4 vs 5, 6 and 8 vs 2, 9 and 12-15). Pseudostomella mandela sp. n. is a fairly large species (up to 481 μm in length), with a cuticular covering made up of tetrancres and relatively long caudal pedicles (up to 44 μm in length ). The most evident autoapomorphic trait of the new species is the presence of 7 pairs of 'cirrata' tubes, two emerging in a lateral position along the pharyngeal region and five from the dorsolateral sides of the trunk. Additional relevant taxonomic characters include: 4 tubes of the anterior series, 11 tubes of the ventrolateral series and 3 tubes of the posterior series per side, 5 papillae on the dorsal margin and 6 papillae on the ventral margin of the oral palps. The high number of putative new species discovered among the South African gastrotrich fauna during our relatively short survey, highlights the relevance of this region with regard to the diversity of this group and stresses once again the importance of investigating new geographic areas in order to improve our understanding of global gastrotrich biodiversity and species richness.

Record of the ‘Arctic’ marine gastrotrich Diuronotus aspetos (Paucitubulatina) from the southern North Sea

A decade ago, Todaro et al. (2005) described a conspicuous genus of marine mesopsammic Gastrotricha. Both known species of Diuronotus are characterized by the possession of one pair of primary plus one pair of secondary adhesive tubes on their furcal appendages. Diuronotus and a second taxon, Musellifer, are both in the family Muselliferidae based on the shared presence of an elongate, ciliated snout-like region called the muzzle and the peculiar ultrastructure of their spermatozoa (Leasi & Todaro 2008, Balsamo et al. 2010). One specimen of Diuronotus aspetos Todaro, Balsamo & Kristensen, 2005 was encountered in sublittoral sand sampled on May 3, 2012 with a Van Veen grab deployed aboard RV Senckenberg at the shoal Langes Riff, northward island Wangerooge, North Sea (N53°49.640′ E007°50.207′), at a depth of 15.5 m. Important morphometric measures are as follows: 436.7 μm total body length, 117 μm pharynx length, pharyngeo-intestinal junction at U26.8 (Fig. 1a, c). Compared to the original description, these lower values are related to the adolescence of the specimen (reproductive organs were absent). However, species-specific traits were still evident such as the keeled, hemi-elliptic scales with a concave posterior edge (Fig. 1b), a mouth with protrusible processes (Fig. 1c, see also Balsamo et al. 2010), and pairs of long (37 μm) secondary and short (14.5 μm) primary adhesive tubes (Fig. 1a, d–f). The two described species of Diuronotus have so far only been recorded from a very limited geographic distribution. D. rupperti Todaro, Balsamo & Kristensen, 2005 is reported from a beach on the island Laeso, Denmark, while D. aspetos was recorded twice (in 1979 and 2006) from shallow sublittoral sand near the forsaken settlement Skansen on Disko Island, Greenland (Fig. 1g, Todaro et al. 2005, Balsamo et al. 2010). A third putative species of Diuronotus possibly inhabits sediments of the east coast of North America (Fig. 1g, see discussion in Todaro et al. 2005). Currently, D. aspetos is hypothesized to represent a ‘High Arctic’ species (Todaro et al. 2005). The new record from the North Sea (Temperate Northern Atlantic realm, see Spalding et al. 2007) indicates i) a wider geographic distribution and ii) a wider temperature tolerance of D. aspetos. However, future surveys have to demonstrate if stable populations of this species exist beyond the Arctic marine realm.

Two new species of Musellifer (Gastrotricha: Chaetonotida) from Florida and Tobago and the systematic placement of the genus within Paucitubulatina

Two new species of marine Gastrotricha, Musellifer reichardti sp. nov. and Musellifer tridentatus sp. nov. (Chaetonotida: Paucitubulatina: Muselliferidae), are described from the Atlantic coast of Florida (USA) and the west coast of Tobago (Trinidad and Tobago), respectively. Both new species are peculiar in that they lack a muzzle bearing the mouth, which is a diagnostic character of the genus. They correspond well to the diagnosis of Musellifer in other morphological features, and genetic data from the 18S rDNA gene of M. reichardti sp. nov. further support the inclusion of the new species in the genus Musellifer. Musellifer reichardti sp. nov. is distinguished by the following combination of characters: blunt head with reduced muzzle; dorsal patches of naked cuticle bearing sensory cilia on either side of the head; ventral locomotory cilia restricted to the pharyngeal region; spined scales; caudal furca with naked adhesive tubes. The new species is a simultaneous hermaphrodite with posterior paired ovaries, paired testes located at mid-body length, and a posterior frontal organ. M. tridentatus sp. nov. is the first species within the genus exhibiting two types of dorsal/lateral scales: anteriormost dorsal and lateral trident-shaped scales and smooth strongly overlapping dorsal scales. The systematic placement of Musellifer within the Paucitubulatina is discussed and emended diagnoses are given for Muselliferidae and Musellifer.

Dendrodasys duplus, a New Gastrotrich Species (Macrodasyida: Dactylopodolidae) from South Korea

A new gastrotrich species of the genus Dendrodasys (Dactylopodolidae) is described on the basis of specimens collected from sublittoral fine sandy bottoms at Uljin, East Sea and at Gujwa, the northeastern coast of Jeju Island, South Korea. Dendrodasys duplus is characterized by a triangular head with lateral lobes extending outward, two pairs of pestle organs posterior to the lateral cephalic lobes, a pair of anterior adhesive tubes, the absence of dorsal, lateral and ventral adhesive tubes, large posterior adhesive tubes arising from the anterior third of the caudal peduncle, and paired testes of different lengths. The genus Dendrodasys is recorded for the first time in East Asia.

Urodasys poculostylis sp. nov., a new stylet-bearing gastrotrich (Macrodasyida) from Capron Shoal, Florida

A new species of marine Gastrotricha, Urodasys poculostylis sp. nov. (Macrodasyida: Macrodasyidae), is described from the sublittoral sediments of Capron Shoal, Florida. The new species is a simultaneous hermaphrodite with a single left testis, a stylet bulb and a frontal organ. The stylet bulb bears a cup-shaped sclerotic stylet up to 20 µm long. Several specimens possessed a large spermatophore within the frontal organ. Urodasys poculostylis sp. nov. can be further distinguished by the presence of three pairs of anterior adhesive tubes distributed in two rows, 14–17 pairs of lateral adhesive tubes with staggered insertions, 5–7 pairs of ventrolateral adhesive tubes, 12–15 pairs of dorsolateral adhesive tubes and two dorsal adhesive tubes.

First record of the enigmatic genusRedudasysKisielewski, 1987 (Gastrotricha: Macrodasyida) from the Northern hemisphere

Gastrotricha Metschnikoff, 1865 is a small phylum of acoelomatic animals common in both marine and freshwater environments. To date, close to 800 species are known from all over the world. The order Macrodasyida Remane, 1925 [Rao & Clausen, 1970] is almost exclusively marine except for the rare genera Marinellina Ruttner-Kolisko, 1955 and Redudasys Kisielewski, 1987. In this study, we present morphological and molecular data for a potentially new species of Redudasys from the Edwards Aquifer, Texas, USA. It is the first record of the genus from the Northern hemisphere. It has only previously been reported from Brazil. The Texan specimen, designated as Redudasys sp., has a single pair of anterior adhesive tubes and is considerably shorter than the specimens reported from Brazil. Molecular data from the 18S rRNA and COI mtDNA genes support a close relationship of Redudasys sp. to Redudasys fornerise Kisielewski, 1987. Barcodes are provided for both Redudasys sp. and R. fornerise. The limited material obtained does not justify the description of a new species, but the record is certainly important from a biogeographical standpoint. The colonization and invasion of marine species into freshwater habitats, in particular those of the Edwards Aquifer, is discussed. Although certain marine gastrotrichs appear to have an astonishing ability to adapt to changes in salinity Redudasys is likely to be a marine relic.