Morphometric and taxonomic approach to describe Heterospio variabilis (Annelida, Longosomatidae), a new species with three size-dependent morphotypes, from the Gulf of California, Eastern Pacific.

The Longosomatidae, a poorly known polychaete family, includes only 23 recognized species; in this study, based on morphometric and taxonomic analyses, we describe a new species with three morphotypes: Heterospio variabilis from the Gulf of California, Mexico. The specimens examined exhibit large morphological variations but were clearly separated from close species due to a unique combination of morphological characters: chaetiger 9 as the first elongated chaetiger, four to eight branchial pairs; chaetae from chaetiger 10 forming rings in two rows, posterior row with thin and robust capillaries, anterior row with subuluncini, aristate spines, acicular spines and thick acicular spines. With the discriminant analysis, carried out on 11 morphometric characters, the presence of three morphological groups were recognized (Wilks' lambda= 0.093, p = 0.0001). However, the variables selected to discriminate the specimens (partial Wilks' lambda > 0.57) were correlated to their size: number of branchiae, body width, prostomium width, rate length CH9/CH1-CH8, length CH1-CH8 and length CH9 (r > 0.5). So, we concluded that they belong to a single species with three morphotypes: morpho A with eight branchial pairs, morpho B with 5-6-7 pairs and morpho C with 4 pairs. No correlations between the distribution of the distinct morphotypes along the eastern gulf shelf and the environmental conditions where they settle were detected.

A remarkable new deep-sea nereidid (Annelida: Nereididae) with gills.

Nereidid polychaetes are well known from shallow marine habitats, but their diversity in the deep sea is poorly known. Here we describe an unusual new nereidid species found at methane seeps off the Pacific coast of Costa Rica. Specimens of Pectinereis strickrotti gen. nov., sp. nov. had been observed dating back to 2009 swimming just above the seafloor at ~1,000 m depth but were not successfully captured until 2018. Male epitokes were collected as well as a fragment of an infaunal female found in a pushcore sample. The specimens were all confirmed as the same species based on mitochondrial COI. Phylogenetic analyses, including one based on available whole mitochondrial genomes for nereidids, revealed no close relative, allowing for the placement of the new species in its own genus within the subfamily Nereidinae. This was supported by the unusual non-reproductive and epitokous morphology, including parapodial cirrostyles as pectinate gills, hooked aciculae, elfin-shoe-shaped ventral cirrophores, and elongate, fusiform dorsal ligules emerging sub-medially to enlarged cirrophores. Additionally, the gill-bearing subfamily Dendronereidinae, generally regarded as a junior synonym of Gymnonereidinae, is reviewed and it is here reinstated and as a monogeneric taxon.

Four new records of Sipuncula (Annelida) from Northern Brazil.

There are very few taxonomic studies of Brazilian sipunculan worms, and the species occurring along the northern coasts are largely understudied. We report herein the occurrence of four shallow water species along the intertidal zones of Bahia and Pernambuco states. Antillesoma antillarum (Grbe & Oersted, 1858) occurs from underneath beach rocks or within sandstone reefs and may reach high densities. The large species Sipunculus (Sipunculus) nudus Linnaeus, 1766, Sipunculus polymyotus Fisher, 1947, and Xenosiphon branchiatus (Fischer, 1895) were collected in sandy-mud, low-energy intertidal environments. For the first time, we report that sipunculans are collected and used as fishing bait by local fishermen in the Western Atlantic. All species are fully described, including notes on their external and internal anatomy.

First record of Oligobregma Kudenov & Blake, 1975 (Annelida: Polychaeta: Scalibregmatidae Malmgren, 1867) from Brazil with the description of three new species.

Oligobregma represents the most speciose genus of Scalibregmatidae with 17 valid species. Most of them occur at great depths and are found living on soft bottoms. Here, we present the descriptions of O. nonatoi sp. nov., O. cruzae sp. nov., and O. bakkeni sp. nov., sampled from the Brazilian continental shelf and slope, and a key to all species of Oligobregma. O. nonatoi sp. nov. differs from its congeners by the presence of a triangular prostomium with short rounded horns, acicular spines on notopodia of chaetigers 14 and on neuropodia of chaetigers 13. Oligobregma cruzae sp. nov. can be distinguished by the presence of a quadrangular prostomium with two short, rounded horns, acicular spines on chaetigers 14, and lyrate chaetae from chaetiger 5. Finally, O. bakkeni sp. nov. is unique among its congeners by the presence of acicular spines with rounded tips. This is the first record of this genus along the Brazilian coast and the specimens were collected on Esprito Santo, Campos and Santos sedimentary basins, both located in Brazilian southeast region. The sampling campaigns were carried out in scientific expeditions related to two research projects: Santos Project Santos Basin Environmental Characterization and Ambes Project Esprito Santo Basin Assessment Project, both coordinated by CENPES/PETROBRAS.

New species of Pseudoscalibregma Ashworth, 1901 (Annelida: Scalibregmatidae Malmgren, 1867) from Brazil.

Pseudoscalibregma Ashworth, 1901 is a small genus of the family Scalibregmatidae Malmgren, 1867. Currently, a total of eight valid species are accepted. Of these, the majority are found at great depths. This work contains the first report of Pseudoscalibregma to the Brazilian coast, with the description of three new species: Pseuscalibregma ermindae sp. nov., P. magalhaesi sp. nov. and P. parapari sp. nov. The material was sampled from the Brazilian southeast region, on Campos and Santos sedimentary basins, during scientific expeditions called Santos ProjectSantos Basin Environmental Characterization and Ambes ProjectEsprito Santo Basin Assessment Project, both coordinated by PETROBRAS/CENPES. We also include an identification key to Pseudoscalibregma species.

New species and record of Dodecaceria (Annelida: Cirratulidae) the Biological Reserve of Rocas Atoll, Brazil, the only atoll in the South Atlantic Ocean.

The polychaete Family Cirratulidae is one of the most abundant and diverse groups of Annelida, although it remains poorly known worldwide. Dodecaceria Ørsted, 1843 is one of the least described genera of Cirratulidae. The present report is the first taxonomic study of the genus Dodecaceria for the Brazilian coast. Cirratulidae were collected at Rocas Atoll, the first Brazilian marine protected area and the only atoll in the South Atlantic Ocean. We described one new species, Dodecaceria zelinhae n. sp., and a new record of D. dibranchiata Blake & Dean, 2019, previously only known from Panama. The new species is distinguished from other Dodecaceria species by having lateral tentacles, a smooth peristomium, 3-5 pairs of branchiae, hooks from chaetiger 11 in notopodia and 9 in neuropodia. Dodecaceria dibranchiata, a Caribbean species, is here recorded for the first time in the South Atlantic Ocean.

Two new species of spionids from the genera Apoprionospio Foster, 1969 and Prionospio Malmgren, 1867 (Annelida: Spionidae) from the Colombian Caribbean.

Two species of genera Apoprionospio and Prionospio are described from the Colombian Caribbean. Apoprionospio sanguarensis sp. nov. and Prionospio gabriellae sp. nov. are new to science. Apoprionospio sanguarensis sp. nov. is distinguished from the three previously described Apoprionospio species by having the smallest body size, triangular prostomium, three pairs of eyes, the branchial pairs 1-3 are cirriform, wrinkled, the anterior notochaetae arranged from chaetiger 2 onwards arranged in three rows, and all hooded hooks lack secondary hoods. Prionospio gabriellae sp. nov. is distinguished from all Prionospio species with five branchial pairs by having dorsal crests across the dorsum on chaetigers 16-25. Closely related species are P. heterobranchia Moore, 1907 and P. caribensis Delgado-Blas, 2014 and Prionospio gabriellae sp. nov. differs from both species in that it has a small medial peak in the dorsal region of prostomium, the first neuropodial lamellae is very small, the shaped of branchial pairs 2 and 3 are cirriform, neuropodial postchaetal lamellae on chaetiger 2 is square, all chaetae of chaetiger 1 are arranged in a row. We propose raising the status of Apoprionospio dayi japonica Imajima, 1989 to the species level as A. japonica Imajima, 1989. A key and a table detailing the most relevant characters of Apoprionospio species and a key to all species of Prionospio with five pairs of branchiae are provided.

Three new Glossoscolex (Annelida: Crassiclitellata: Glossoscolecidae) in the truncatus group from the Brazilian Atlantic Forest.

Three new earthworm species of Glossoscolex (Glossoscolex) in the truncatus species group (intra-clitellar male pores on segment 17) are described: Glossoscolex araucariaensis sp. nov., Glossoscolex cardosoi sp. nov., and Glossoscolex santarosaensis sp. nov. from the Brazilian Atlantic Forest. The three earthworm species were distinguished based on the shape and position of the copulatory pouches (all species), the shape of the calciferous glands (G. santarosaensis) and by the presence of tubercula pubertatis and seminal vesicles restricted to segment 12 (G. cardosoi). All are endogeic, unpigmented and were found in low abundances in the topsoil (0-20 cm depth) of Araucaria forest and plantations, a lowland grass pasture and a shrubby grassland, respectively, and are known only from their type-localities. A table containing some of the main internal and external morphological characteristics of the 29 species/subspecies of the Glossoscolex truncatus group is provided in order to assist comparisons within species. Glossoscolex grandis ibirai Righi, 1971 is raised to species rank due to longer extent of clitellum and presence of genital markings, compared to Glossoscolex grandis (Michaelsen, 1892); furthermore, a new subgroup (matogrossensis) of Glossoscolex (Glossoscolex) is proposed to accomodate G. matogrossensis Righi, 1984, with intraclitellar male pores in 15/16. Some considerations on the ecological and taxonomic affinities within the truncatus group are presented, but further studies, particularly genetic are needed in order to better assess phylogenetic relationships within Glossoscolex (Glossoscolex) species groups.

A new semiaquatic worm (Annelida, Oligochaeta) from southeastern Mexican tropical rain forests.

A new Oligochaete worm genus with a single species is described from tropical rain forests of Southern Mexico. Lacandodrilus paludosus Fragoso & Rojas gen. et sp. nov., found in sandy and acid poor swampy soils, presented a characteristic morphology of semiaquatic oligochaetes. The new taxon is holandric, with male pores and ovaries in segment 13, with genital prostatic- like lobular glands in segments 13 and 14 and with long seminal vesicles contained within ovisacs. It is also characterized by exonephric holonephridia covered by a peritoneal granular layer, septal glands and long vascular commissures in former segments. It presents a pair of spermathecae without diverticula in segment 10 and it lacks gizzards, typhlosole or esophagus glands. The new taxon is tentatively placed in family Alluroididae, waiting for additional histological studies that will clarify some characters.

Small worms of Sthenelanellinae, Pholoinae and Pisioninae (Annelida, Sigalionidae) from the Tropical Northwestern Atlantic.

The family Sigalionidae is characterized, among other features, by including scale worms with large bodies. However, among sigalionids, the subfamilies Sthenelanellinae, Pholoinae, and Pisioninae stand out by their small representatives with few segments and fragile bodies. In the Tropical Northwestern Atlantic, which includes part of the Gulf of Mexico and the Caribbean Sea, these subfamilies have been rarely studied, with few species recorded, and questionable records. This contribution aims to improve the knowledge of sthenelanellins, pholoins, and pisionins in the region through a faunistic study based on material from two Mexican scientific collections: the Reference Collection of Laboratorio de Biodiversidad y Cambio Climático (BIOMARCCA) and the Reference Collection of Benthos (ECOSUR) of El Colegio de la Frontera Sur. Pisione wolfi is confirmed from the Tropical Northwestern Atlantic, and three new species are described: Sthenelanella pechi sp. nov., S. sarae sp. nov. and Taylorpholoe anabelae sp. nov. A key to all Sthenelanella and Taylorpholoe species is also included.

Unravelling the diversity of Scalibregma Rathke, 1843 (Annelida: Polychaeta: Scalibregmatidae) from southeast Brazilian coast.

Scalibregmatidae Malmgren, 1867 is a relatively small family of annelids, with only two taxa reported to Brazil. In this work, we expand the scientific knowledge of this group by presenting two new Scalibregma Rathke, 1843 species. The new species S. lanai sp. nov. and S. cinthyae sp. nov. were collected during an expedition to the Campos and Santos oceanographic basins. Scalibregma cinthyae sp. nov. is unique among its congeners by the presence of two rows of paired lobes on the mouths upper and lower lips, whereas S. lanai sp. nov. is unique among its congeners by the presence of two rows of paired lobes on the mouths lower lip, branchiae from chaetigers 35, and lyrate chaetae with equal tynes. We provide an identification key to all Scalibregma species.

A new species of Euclymene (Maldanidae, Annelida) from Brazil, with new combinations, and phylogenetic implications for Euclymeninae.

Maldanids are tube-building polychaetes, known as bamboo-worms; inhabit diverse marine regions throughout the world. The subfamily Euclymeninae was proposed to include forms with anal and cephalic plates, a funnel-shaped pygidium, and a terminal anus. Euclymene, the type genus of Euclymeninae, has about 18 valid species. Euclymene vidali sp. nov. is defined and members of the species described from Northeastern Brazil. Members of this species have 23 chaetigers, and one pre-pygidial achaetous segment; nuchal grooves extend through three quarters of the cephalic plate, and there is one acicular spine with a denticulate tip. Euclymene africana, and E. watsoni, are here recognized, respectively, as Isocirrus africana comb. nov., and I. watsoni comb. nov. Three monotypic genera are invalid: Macroclymenella, Eupraxillella, and Pseudoclyemene; their species should be recognized as Clymenella stewartensis com. nov., Praxillella antarctica com. nov., and Praxillela quadrilobata com. nov., respectively. An identification key and a comparative table for all species of Euclymene are provided. A comparative table for all genera of Euclymeninae is also furnished. The paraphyletic status of Euclymene and Euclymeninae is discussed. The taxon Maldanoplaca is not code compliant and should only be regarded as an informal name.

Two new deep-sea species of Capitella (Annelida: Capitellidae) from sunken wood in the Northeast Pacific.

Natural and experimental wood falls harbor a rich and abundant macrofaunal community in the deep-sea. Two undescribed capitellids have been collected from wood species bundles deployed at 3,100 m at the Deadwood 2 site in Monterey Bay and several other locations in the northeastern Pacific. Capitella blakei sp. nov. is a widely distributed deep-sea capitellid in the northeastern Pacific occurring from the Monterey canyon north to the Endeavour segment of the San Juan de Fuca Ridge, a range of almost 1,400 km. It belongs to a group of Capitella species having only individuals with male external characteristics, chaetigers 17 with notopodial and neuropodial capillaries and is readily distinguished from its congeners by the presence of a peristomium clearly separated from prostomium, deep lateral and ventral grooves, and methyl green staining pattern. Capitella multibranchiata sp. nov. is unique in the genus by the presence of branchiae on abdominal notopodial and neuropodial segments. The adult morphology of both species is described and compared to their most apparently related congeners. Our results have shown a greater diversity of deep-sea Capitella than previously known. The wide geographical distribution of C. blakei sp. nov. on wood habitats indicates that these wood falls may be functioning as ecological and evolutionary stepping-stones between the enriched sediments of vents and seeps.

Kirkegaardia Blake, 2016 (Annelida: Cirratulidae) from Southeastern Brazil with description of nine new species.

This is the first taxonomic study of cirratulid polychaetes of the genus Kirkegaardia Blake, 2016 from Brazil. Nine new species of the genus are described from the Southern Brazilian coast (50-3000 m deep). The genus Kirkegaardia is generally subdivided into three distinct groups of species (Kirkegaardia dorsobranchialis-heterochaeta, Kirkegaardia baptisteae-tesselata and Kirkegaardia luticastella) and several out-group species for which relationships remains to be defined. In this study, new species were included in the Kirkegaardia dorsobranchialis-heterochaeta and Kirkegaardia baptisteae-tesselata groups. Kirkegaardia dorsobranchialis-heterochaeta is characterized by thoracic parapodia elevated producing a channel between the notopodia, elongate pre-setigerous region that is either entirely smooth or modified with a dorsal ridge and/or rings, and noto- and neurosetae capillaries denticulated. As belonging to this group, K. blakei sp. nov., K. brisae sp. nov., K. goytaca sp. nov., K. jongo sp. nov. and K. papaveroi sp. nov. are described here. Kirkegaardia baptisteae-tesselata includes species that lack thoracic parapodia elevated and mid-dorsal thoracic groove, although a dorsal ridge is sometimes developed. In the pre-setigerous region dorsal ridges and rings are present or absent. Most species in this group have neurosetae denticulated, and notosetae capillaries of other types. This study adds K. helenae sp. nov., K. medusa sp. nov., K. nupem sp. nov. and K. zafirae sp. nov. to the latter species group. In addition, two new records are provided for K. hampsoni. A key to cirratulid polychaete species reported from Brazilian waters is provided.

Capitellidae (Annelida) from the Brazilian Continental Margin (SW Atlantic): new occurrences of three genera and description of new species.

The Brazilian Continental Margin hosts several deep seafloor landscapes. However, this deep margin is still poorly studied and monitored, compared to coastal and continental shelf areas, historically limited to areas of particular economic interest. Some studies financed by the Brazilian oil and gas company have been conducted off Southeast (SE) Brazil (Esprito Santo and Campos Basins) as part of the environmental licensing process for resource exploration. Similar results showed that annelid polychaetes dominated on the continental shelf and upper slope. Within a wide bathymetric range, Capitellidae species belonging to three different genera represented new records for Brazil: Mastobranchus Eisig, 1887, Peresiella Harmelin, 1968, and Polymastigos Green, 2002. Mastobranchus braziliensis sp. nov. was found in shallow waters (20147m) of both Esprito Santo and Campos Basins; Peresiella megapapilata sp. nov. occurred from 21 to 446m of both Esprito Santo and Campos Basins; and Polymastigos profundus sp. nov. inhabited greater depths (9901361m) of the Esprito Santo Basin only. Three new species are described and compared to other species of the respective genus, the diagnosis of some genera amended and the type material of Mastobranchus loii Gallardo, 1968 redescribed. Although the three genera have the same number of thoracic chaetigers, they present several morphological differences, and the current effort being made is to translate those differences into characters to be included on the generic diagnosis of each genus. Additionally, two new morphological characters were proposed for the family, the shape of thoracic chaetigers and depth of intersegmental groove.

Revision of Meiodorvillea Jumars, 1974 (Annelida: Dorvilleidae) including descriptions of three new species from the Southwestern Atlantic Ocean.

Meiodorvillea Jumars, 1974 is a little-known genus of Dorvilleidae Chamberlin, 1919, characterized by its small size and reduced appendages and jaw apparatus. A revision of the genus is presented, including analysis of the type material of M. minuta (Hartman, 1965) and M. apalpata Jumars, 1974, as well as specimens collected from shelf and slope continental areas in Brazil. A neotype was designated for M. minuta and its distribution was extended to Brazil. The identity of M. chilensis (Hartmann-Schröder, 1965) is questioned and three new species from 21 to 1,300.7 meters depth are also described. Meiodorvillea penhae sp. nov. has furcate chaeta only in the first anterior chaetigers. In contrast, Meiodorvillea hartmanae sp. nov. has very small palps and asymmetrical thin furcate chaeta and Meiodorvillea jumarsi sp. nov. has dorsal cirri and geniculate chaeta only in the first anterior chaetigers.

Sabellariids (Annelida: Sedentaria: Sabellariidae) from shallow waters of the Gulf of Mexico and the Caribbean Sea, including three new species.

The Sabellariidae has been scarcely studied in the Gulf of Mexico and the Caribbean Sea, and there are 18 species recorded out of 140 species known in the world. This work aims to improve the knowledge of the sabellariids in the northwestern tropical Atlantic region, provide standardized descriptions, and generate taxonomic identification keys. Sabellariids from three scientific collections were revised: Reference Collection of Laboratorio de Poliquetos, El Colegio de la Frontera Sur (ECOSUR), Chetumal, Collection of Laboratorio de Biodiversidad y Cambio Climtico, ECOSUR, Campeche and Invertebrate Zoology Collection of Florida Natural History Museum, University of Florida, Gainesville. Three new species are described: Idanthyrsus bastidai n. sp. and I. mikeli n. sp. from Venezuela, and Sabellaria salazari n. sp. from the Yucat Peninsula. In addition, new records of S. floridensis Hartman, 1944, S. vulgaris Verrill, 1873, and Phragmatopoma caudata Kryer in Mrch, 1863 are provided.

Segmented worms (Phylum Annelida): a celebration of twenty years of progress through Zootaxa and call for action on the taxonomic work that remains.

Zootaxa has been the leading journal on invertebrate systematics especially within Annelida. Our current estimates indicate annelids include approximately 20,200 valid species of polychaetes, oligochaetes, leeches, sipunculans and echiurans. We include herein the impact of Zootaxa on the description of new annelid species in the last two decades. Since 2001, there have been over 1,300 new annelid taxa published in about 630 papers. The majority of these are polychaetes (921 new species and 40 new genera) followed by oligochaetes (308 new species and 10 new genera) and leeches (21 new species). The numerous papers dealing with new polychaete species have provided us a clear picture on which polychaete families have had the most taxonomic effort and which authors and countries have been the most prolific of descriptions of new taxa. An estimated additional 10,000+ species remain to be described in the phylum, thus we urge annelid workers to continue their efforts and aid in training a new generation of taxonomists focused on this ecologically important group.

A synopsis of Salvatoria McIntosh, 1885 (Annelida: Syllidae: Exogoninae) from Brazilian coastal and oceanic waters.

We compiled the records for the genus Salvatoria from Brazilian coastal and oceanic habitats, collected by several projects along the years. Here we present 12 species, eight of which already reported-S. breviarticulata comb. nov., S. clavata, S. euritmica, S. heterocirra, S. limbata, S. longiarticulata comb. nov., S. neapolitana and S. cf. nitidula-with comments regarding the confidence of some of these records. We also describe three new species, S. marielleae n. sp. and Salvatoria nitiduloides n. sp., based on material from Fernando de Noronha and Trindade islands, off the Northeastern Brazilian coast, and S. ypsiloides n. sp., from Fernando de Noronha and also, Campos Basin, off Southeastern Brazilian coast, in depths down to 970 m. Finally, we report a probably undescribed species, Salvatoria sp., represented by only one specimen lacking median antenna, preventing us to proceed with further identification properly. A dichotomous identification key and a comparative table with morphological data of specimens belonging to these species are also provided.

Ten new species of Phyllodoce Lamarck, 1818 (Phyllodocidae, Annelida) from Brazil.

Herein we provide a taxonomic revision of Phyllodoce species from Brazil, describing 10 new species in addition to two new records, Phyllodoce longipes Kinberg, 1866 and Phyllodoce cf. madeirensis Langerhans, 1880. Phyllodoce sp. A. and Phyllodoce sp. B. are probably new but the number and condition of available specimens do not provide adequate and reliable diagnostic features for a formal description. These species have been collected in diverse marine and estuarine environments from shallow estuarine bottoms to continental shelf and slope sediments and submarine canyons from off southern and southeastern Brazil. A key to the fourteen species of Phyllodoce occurring in Brazil is also given.