A new member of the genus Antarctonemertes (Hoplonemertea, Nemertea) from Antarctic waters

11 p.The phylum Nemertea is an important component of the benthic ecosystems of the Southern Ocean, but its biodiversity is still relatively poorly known in Antarctic waters. There are few common and well-known nemertean species occurring in the shallow Antarctic waters, and these include the congeneric Antarctonemertes valida (Bürger, 1893) and Antarctonemertes riesgoae Taboada et al., 2013, two relatively small brooding hoplonemerteans whose females lay eggs inside cocoons. A third Antarctic member of the genus, Antarctonemertes belgica (Bürger, 1904), was reported only in the original descrip-tion. Here we document the existence of a fourth Antarctic member of the genus Antarctonemertes originally described as Tetrastemma unilineatum Joubin, 1910. Our phylogenetic analysis resulted into the placement of the new Antarctonemertes in a robustly supported clade ?Antarctic Antarctonemertes? containing the other two congeneric Antarctic species (A. valida and A. riesgoae), and pairwise COI molecular distances between the three species ranged from 5.2 to 6.2% (p distance). The analysis of 104 COI sequences of the three species showed star-like haplotype networks, as in other studies on Antarctic invertebrates. Antarctonemertes unilineata comb. nov. is similar in shape to its Antarctic congeneric relatives and its most prominent morphological character is a dorsal mid-longitudinal band present along the body. We also document the pres-ence of a cocoon built by females of A. unilineata comb. nov., a character shared with its Antarctic congeners analysed here. Although the four Antarctic Antarctonemertes species appear to overlap their distribution, A. riesgoae, A. valida and A. belgica appear in sympatry in the West Antarctic shores while A. unilineata comb. nov. has been mainly found in the East Antarctic shores and sub-Antarctic Islands.DistantcomAustralian Antarctic Divisio

Diversity of interstitial nemerteans of the genus Ototyphlonemertes (Nemertea: Monostilifera: Ototyphlonemertidae) in the South China Sea, with a comment on the distribution pattern of the genus

The genus Ototyphlonemertes Diesing, 1863, consisting of 33 named species and numerous unnamed morphospecies/molecular entities, is a unique group of nemerteans that possess cerebral statocysts and specifically live in coarse-grained sands. Only eight named species of this genus have yet been recorded from the Indo-Polynesian biogeographic province, which harbors the highest marine biodiversity in the world. In recent years, Ototyphlonemertes were collected from eight sites along the South China Sea coasts. Nine species/entities were revealed by four phylogenetic markers (COI, 16S, 18S, 28S) analyzed by three species delimitation methods: Automatic Barcode Gap Discovery (ABGD), Poisson Tree Process (PTP), and Generalized Mixed Yule Coalescent model (GMYC). Six entities are described as new species based on integration of morphological and molecular species delimitations: Ototyphlonemertes conicobasis sp. nov., Ototyphlonemertes coralli sp. nov., Ototyphlonemertes similis sp. nov., Ototyphlonemertes sinica sp. nov., Ototyphlonemertes subrubra sp. nov., and Ototyphlonemertes yingge sp. nov. No morphological differences were detected between two entities and Ototyphlonemertes chernyshevi Kajihara et al., 2018, despite large genetic differences, so are treated as candidate species. Ototyphlonemertes ani Chernyshev, 2007 is first recorded in China. Based mostly on results of phylogenetic analyses, two previously established subgenera are re-defined, and a new subgenus, Procso subgen. nov., is established. Through reviewing the existing studies, we recognize 101 species/entities of Ototyphlonemertes, which are distributed in 18 marine biogeographic provinces. Most (88.1%) of them are endemic to a single biogeographic province, and evolutionary lineages endemic to a geographic area are not uncommon. Maximum diversity has been recorded in the Indo-Polynesian Province (22 species), though sampling to date has covered only a small part of the biogeographic province

Fasciculonemertes arenicola gen. et sp. n. (Hoplonemertini monostilifera) de Chile Central

É descrita urna nova espécie de hoplonemertino monostilífero coletada numa praia arenosa em S. Molles, Chile Central. Para sua identificação as seguintes características foram consideradas: a musculatura longitudinal da porção anterior do corpo é dividida em 2 camadas por tecido conjuntivo; ausência de septo precerebral; músculos retratores da cabeça relacionados à camada interna da musculatura longitudinal; existência de musculatura diagonal e dorso-ventral. Outras características taxonómicas encontradas foram: células do neurocordão presentes no gânglio ventral; cordão nervoso lateral com um só núcleo de fibras; órgãos cerebrais localizados anteriormente ao cérebro e canal cerebral com bifurcação curta; vasos sangüíneos laterais atravessando o anel cerebral; bainha muscular da probóscide disposta em 2 camadas separadas; bainha da probóscide alcança o terço posterior do corpo. Essa combinação de caracteres excluem esta espécie de qualquer Monostilifera conhecido e por isso um género novo está sendo proposto

On Fourteen Monostiliferous Hoplonemerteans from the Izu Peninsula, Middle Japan

Of the fourteen species dealt with in this paper, two (Amphiporus cervicalis, Nipponnemertes punctatulus) have previously been reported from Japan; three others (A. imparispinosus, N. pulchra, Tetrastemma melanocephalum) are added to the fauna. Four species (Emplectonema mitsuii, Paranemertes katoi, N. ogumai, T. roseocephalum) have been discussed by Crandall, Kajihara, Mawatari, and Iwata (2001). Three of the nemerteans (A cervicalis, A. imparispinosus, N. punctatulus) are known to occur in the eastern North Pacific, and two were originally found in Europe. Five species, belonging to the genera Paranemertes, Amphiporus, Nipponnemertes, and Tetrastemma, though long known from the Japanese fauna, have not yet been given specific names

Nemertinos bentónicos asociados al litoral rocoso en la región de Santa Marta. un enfoque morfológico y molecular

Los nemertinos son animales bilaterales, no segmentados, cuya característica principal es poseer una probóscide retráctil, alojada en una cavidad celómica independiente del sistema digestivo, conocida como rincocele. De las 1275 especies descritas, 36 han sido reportadas para el Mar Caribe, y de estas, tres para Colombia: Ototyphlonemertes erneba, Ototyphlonemertes lactea y Baseodiscus mexicanus. Aunque en estudios realizados sobre ecosistemas bentónicos de Colombia los nemertinos son abundantes, estos son reportados simplemente como “Nemertea”. En esta investigación, 61 ejemplares fueron colectados en litorales rocosos de Santa Marta (Inca-Inca, Bahía Concha y Taganga), estos fueron identificados basados en caracteres morfológicos como: color y forma, presencia de surcos, cirros, ocelos y disposición de la musculatura, vasos sanguíneos y cordones nerviosos. Se encontraron 19 especies: Amphiporus cruentatus, Amphiporus cf. chraceus, Amphiporus texanus, Baseodiscus delineatus, Cratenemertidae sp.,Dushia cf. atra, Lineus stigmatus, Micrura ignea, Micrura chlorapardalis, Nemertopsis bivittata, Ototyphlonemertes erneba, Ototyphlonemertes lactea, Punnettia cf. natans, Tetrastemma sp.1, Tetrastemma sp.2, Tetrastemma sp.3, Tubulanus rhabdotus, Zygonemertes fragariae y Zygonemertes virescens, las cuales pertenecen a a nueve familias: Amphiporidae, Cratenemertidae, Drepanophoridae, Emplectonematidae, Lineidae, Ototyphlonemertidae, Tetrastemmatidae, Tubulanidae y Valencinidae. A seis de estas especies (A. texanus, Cratenemertidae sp., M. ignea, N. bivittata, O. lactea, Z. virescens) se les realizó un análisis molecular de código de barras genético con base en la secuenciación de un fragmento del gen que codifica para la subunidad uno de la enzima Citocromo C Oxidasa. 17 especies representan nuevo registros para Colombia: Amphiporus cruentatus, Amphiporus cf. ochraceus, Amphiporus texanus, Baseodiscus delineatus, Cratenemertidae sp., Dushia cf. atra, Lineus stigmatus, Micrura ignea, Micrura chlorapardalis, Nemertopsis bivittata, Punnettia cf. natans, Tetrastemma sp.1, Tetrastemma sp.2, Tetrastemma sp.3, Tubulanus rhabdotus, Zygonemertes fragariae y Zygonemertes virescens. Dushia cf. atra fue la especie más común y abundante. La nemertifauna encontrada en la región de Santa Marta parece ser un sobre lapamiento de las especies presentes en la Florida, Golfo de México y Centroamérica, con las que se encuentran en Brasil; esto puede ser explicado por la convergencia de corrientes como: Guyana, Caribe, Norte de Brasil y la contracorriente de Panamá Colombia en el área de estudio. Este trabajo representa el primer aporte a la taxonomía de los nemertinos en Colombia; las imágenes de alta calidad contenidas en el documento, la clave taxonómica, las descripciones cortas y los códigos de barras genéticos, constituyen información útil para las investigaciones que se realicen sobre los ecosistemas bentónicos en el país y el desarrollo de futuras investigaciones sobre distintos aspectos de la biología de estos organismos

Species Identification and Delimitation in Nemerteans

The accurate identification and delimitation of species constitute the basis for assessing the biodiversity and phylogenetic relationships within the taxon Nemertea. However, working on nemertean taxonomy is challenging for many reasons. The external and internal morphology are relatively simple with only a few diagnostic characters. This makes it very difficult to identify species based solely on visual inspection. Additionally, the muddled taxonomic history of many genera and species hampers assigning identified species to the current systematic background. As observed in many other taxa, the identification and delimitation of nemertean species has shifted from traditional morphological-based to molecular-based taxonomy. The usage of either methodology bears its own pitfalls. Most of our taxonomic knowledge is based on morphological data and relies on histological sections, which are difficult to compile and analyze. Additionally, the overall interpretation of morphological characters lacks a widely applied standard and is therefore subjective. DNA taxonomy holds great promise for faster species identification. This methodology is based on the comparison of sequence data, relying on the presence of a barcoding gap and high coverage of the target taxa within sequence databases. The latter is, however, not given in a majority of nemertean species, rendering a DNA-based approach for species identification problematic. Within this thesis, I present three representative examples encountered in nemertean taxonomy. Chapters 2 and 3 concern the description of previously unknown species, one of which represents a cryptic species. Chapter 4 deals with the re-description of a nemertean species with a confusing nomenclatural history. With this thesis I give suggestions as to how species can be delimited, identified, and described in the future. I conclude that in most cases, an integrative taxonomic approach combining molecular data, external characters, and histological-based morphology constitute a stable background to safely delimit and identify nemertean species. The species descriptions presented herein show that if one method fails or is of limited conclusiveness, the application of the other approaches can assist to succeed in delimiting species boundaries. Molecular sequence data are of major importance especially in terms of identifying and delimiting cryptic nemertean species. In these cases, molecular sequence data combined with external characters present a solid basis for species descriptions. Furthermore, molecular sequence data should always be included in species descriptions even if its relevance is not immediately apparent. As more data is assembled, it should and will provide a solid backbone for future barcoding identification and phylogenetic reconstructions. I suggest basing species re-descriptions on more than just one methodology in an integrative taxonomic approach. Including data from different methodological or biological backgrounds allows assessing species boundaries from multiple perspectives and additionally provides a link to the traditional knowledge of nemertean taxonomy

Molecular Phylogeny of the Genus Nipponnemertes (Nemertea: Monostilifera: Cratenemertidae) and Descriptions of 10 New Species, With Notes on Small Body Size in a Newly Discovered Clade

Nemerteans, or ribbon worms, have been reported from intertidal to hadal depths, often showing bathymetrically wide distribution in genus levels. Although current nemertean systematics practices require to provide DNA sequences and infer phylogenetic relationships with suitable molecular markers, previous molecular systematics on nemerteans are mostly biased toward shallow-water species. Members in the genus Nipponnemertes occur worldwide, from tropical to polar waters and intertidal to bathyal waters. Molecular phylogenetic studies are scarce for the genus; only six shallow-water species of 18 species in the genus were subject to molecular phylogeny. Thus, Nipponnemertes is one candidate that needs to be assessed by genetic approaches. In this study, we performed molecular phylogenetic analyses using 59 specimens in 23 species based on partial sequences of two mitochondrial (16S rRNA and cytochrome c oxidase subunit I) and three nuclear gene markers (18S rRNA, 28S rRNA, and histone H3). Our extensive sampling from intertidal to bathyal waters in the Northwest Pacific significantly updated the fauna of Nipponnemertes in this region from four to 17 species. We herein establish 10 new species and provide an updated species list concisely summarizing all the congeners known from the world. Our phylogenetic tree indicated three major lineages within the genus (herein referred to as “Clade A, B, and C”), each presumably characterized by the combination of morphological characters in the head region. Members in Clade A are: Nipponnemertes pulchra (Johnston, 1837), Nipponnemertes ogumai (Yamaoka, 1947), and several unidentified congeners, characterized by having demarcated head without cephalic patches; members in Clade B are: Nipponnemertes crypta sp. nov., Nipponnemertes jambio sp. nov., Nipponnemertes neonilae sp. nov., and Nipponnemertes ojimaorum sp. nov., species having demarcated head with cephalic patches; members in Clade C are: Nipponnemertes ganahai sp. nov., Nipponnemertes kozaensis sp. nov., Nipponnemertes lactea sp. nov., Nipponnemertes notoensis sp. nov., Nipponnemertes ornata sp. nov., Nipponnemertes sugashimaensis sp. nov., and two unidentified forms collected off Jogashima (Japan) and Guam (USA), species with non-demarcated head lacking cephalic patches. Furthermore, we discuss the evolution of remarkably small body size retained among Clade C

The freshwater ribbon-worm Prostoma graecense (Hoplonemertea: Monostilifera) in South America (Argentina)

The morphological species Prostoma graecense (Böhmig, 1892) is reported for the first time fromArgentina and South America. Some diagnostic characters, such as the ciliated epithelium of thenon-rhynchodaeal oesophagus and the backward extension of the cephalic glands up to the braincommisure, were confirmed for the Argentine material; the rhynchodaeal longitudinal muscleswere present, but did not form a thick layer as expected from some previous descriptions. AddingSouth America to its distribution range supports the hypothesis that this morphotype Prostomagraecense actuallyhas a cosmopolitan distribution.Fil: Tamburi, Nicolas Eduardo. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Cazzaniga, Néstor Jorge. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

Marine, benthonic nemerteans

10 p. : ill. ; 24 cm