Thiago Quintão Araujo

New data on freshwater psammic Gastrotricha from Brazil.

Abstract Current knowledge of freshwater gastrotrich fauna from Brazil is underestimated as only two studies are available. The present communication is a taxonomic account of the first-ever survey of freshwater Gastrotricha in Minas Gerais State. Samplings were carried out yielding six species of three Chaetonotidae genera: Aspidiophorus cf. pleustonicus, Ichthydium cf. chaetiferum, Chaetonotus acanthocephalus, Chaetonotus heideri, Chaetonotus cf. succinctus, Chaetonotus sp., and also an undescribed species belonging to the genus Redudasys (incertae sedis): this is the first finding of specimens of Redudasys outside of original type locality. These preliminary observations suggest that the knowledge of the biodiversity of Gastrotricha in the Minas Gerais State, as well as in the whole Brazil, will certainly increase as further investigations are undertaken, and that freshwater Macrodasyida may be more common than previously thought.

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 of Oregodasys (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.

New records of Gastrotricha from Minas Gerais, Brazil

Identification of Gastrotricha from Sempre-Vivas National Park, Minas Gerais, is reported here for the first time. The samples from 29 locations yielded new records for Brazil. These are species of the genus Marinellina Ruttner-Kolisko (Ruttner-Kolisko A. 1955. Rheomorpha neiswestnovae und Marinellina flagellata, zwei phylogenetisch interessante Wurmtypen aus dem Süsswasserpsammon. Österr Zool. 6:55–69) reported only in the original description in Europe and never collected again, belonging to the order Macrodasyida, and eight more species of Chaetonotida. One new form of Chaetonotus acanthocephalus is described; five species appear to be previously unknown taxa. One species is first identified from the state of Minas Gerais.

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

Pseudostomella dolichopoda Todaro, 2012 and P. cataphracta Ruppert, 1970 (Gastrotricha: Thaumastodermatidae): new records from Brazil and USA and an updated key to the genus

Pseudostomella dolichopoda was originally described from the north coast of Sao Paulo, Brazil, and P. cataphracta from North Carolina, USA. Herein we report new distributional records of both species: P. dolichopoda is recorded from Espirito Santo, Brazil and P. cataphracta from Florida, USA. An updated identification key for the genus Pseudostomella is also provided.

Chave de identificação de Gastrotricha de águas continentais e marinhas do Brasil

Gastrotricha are free-living microscopic invertebrates, characterized by a meiobenthic life style in freshwater and marine habitats. In spite of the high number of individuals and their ecological importance, this taxon is underestimated in Brazil. Considering the importance of the Gastrotricha in the interstitial benthic community we aimed to help and stimulate new research with this group in Brazil. Thus, the present study provides a taxonomic key for the Brazilian freshwater and marine Gastrotricha based on the available data. Furthermore, we pointed out methods of collecting, preserving and photographing Gastrotricha. Portuguese terminologies of the main morphological characters used to identify species were also listed as a glossary.

Phylogeny of Pseudostomella Swedmark, 1956 (Gastrotricha: Macrodasyida) base on morphological data and first insights on the historical biogeography of Thaumastodermatidae

Abstract The genus Pseudostomella is comprosed of 17 species distributed in distinct coastal and shelf areas of the world. This taxon is characterized by a fleshy preoral apparatus, which is unique to the family and easily distinguishes species of Pseudostomella from species of the other 7 genera. The present study has two aims: 1) provide a phylogenetic reconstruction based on morphological characters using all valid species of the genus Pseudostomella; and 2) perform a Brooks Parsimony Analysis (BPA) based on new and published phylogenetic analyses to determine the biogeographical history of the thaumastodermatid lineage. The cladistic analysis conducted here supports the monophyly of Pseudostomella and the internal branchs are also supported by a relative high number of well-defined synapomorphies. Regarding historical biogeography, our results suggest that the thaumastodermatid diversification first occurred in epicontinental seas from the southern margin of Gondwana. These findings for thaumastodermatid gastrotrichs are similar to those of other historical biogeographical studies on marine invertebrates.

Description of a new species of Thaumastoderma (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.

Erratum to: A new species of Pseudostomella (Gastrotricha, Thaumastodermatidae) from Brazil

Pseudostomodella in the title and along the text is incorrect. The correct form is Pseudostomella.