María Teresa Aguado

Description of a new syllid species as a model for evolutionary research of reproduction and regeneration in annelids

Syllids are one of the most speciose annelid taxa and characterized by their variety of reproductive modes. We provide the description of a new species of Syllidae (Annelida, Phyllodocida), Typosyllis antoni n. sp., which is characterized by its distinct color pattern consisting of transversal red lines on the dorsum of anterior segments; long antennae and dorsal cirri with strong alternation in length; bidentate chaetae falciger like with long spinulation on edge, one tiny and thin acicula appearing in posterior segments in addition to thicker and pointed one, and a long proventricle. A phylogenetic analysis of Syllinae based on three genes supports that T. antoni n. sp. is sister species to Typosyllis heronislandensis. This sister group relationship may indicate a common ancestor from the Pacific. Moreover, we recommend several steps to unify the taxonomy with phylogenetic knowledge of this group. Using immunocytochemistry coupled with confocal laser scanning microscopy (cLSM), we describe the internal morphology of this species. The body wall is composed of two dorsal and two ventral longitudinal muscle bundles that form a distinct inner layer. The outer or “circular layer” of body wall musculature is represented by prominent transverse muscle fibers that exhibit a semicircular arrangement. The musculature of the uniramous parapodia is characterized by distinct parapodial retractor muscles, acicular protractor muscles, as well as prominent acicular and chaetal flexor muscle bundles. T. antoni n. sp. reproduces by schizogamic scissiparity producing dicerous stolons. This species is able to regenerate the anterior end, including the prostomium, the first chaetae-less segment with all appendages, and some additional chaetigers, depending on the dissection side. Regeneration of the proventricle, ventricle, caeca, or pharyngeal tooth is not detectable. In contrast, regeneration of the posterior end appears to be complete. The available data makes T. antoni n. sp. to be one of the best investigated syllids, emphasizing its potential as model for the whole group. Our analysis establishes a framework for future studies on the evolution of reproductive modes in Syllidae, and we outline research questions how they are related to regeneration and development.

Re-description of some enigmatic genera of Syllidae (Phyllodocida: Polychaeta)

Several type series of unusual and poorly known genera of Syllidae have been examined. New diagnoses for the following genera and re-descriptions of their type species are provided: Anguillosyllis , Clavisyllis , Lamellisyllis and Nuchalosyllis ; Brachysyllis , previously synonymized with Dioplosyllis , is herein considered to be a valid taxon. The species Brachysyllis infuscata is also re-described. Three genera are considered to be non-valid taxa: Braniella , synonymous with Anguillosyllis ; Alluaudella , synonymous with Odontosyllis ; and Exogonella , synonymous with Parexogone . Their type species herein are re-described and assigned to their corresponding valid genus. Finally, Exogonoides is considered nomina dubia since its relationships with other syllids could not be established. Keys to species of Anguillosyllis and Brachysyllis are also included.

Review of the Symbiotic Genus Haplosyllides (Polychaeta: Syllidae), with a Description of a New Species

The genus Haplosyllides was considered as monotypic, with H. floridana as the only valid species. The present revision includes two more species in this genus: H. aberrans comb. nov. and H. ophiocomae sp. nov. Syllis (Haplosyllis) aberrans (from Vietnam) was considered a junior synonym of H. floridana (from the Caribbean). The finding of additional specimens from Vietnam and Indonesia, and the study of the type series, allowed us to redescribe H. aberrans comb. nov. on the basis of morphological, ecological and biogeographical characteristics. Haplosyllides aberrans comb. nov. differs from H. floridana in having posterior simple chaetae with tips twice as long, a pharyngeal tooth in all non-reproductive individuals, and the granules inside the dorsal cirri oval, elongated, and roughly distributed in longitudinal parallel rows. Haplosyllides ophiocomae sp. nov. was previously reported (as H. aberrans) from Puerto Rico. Although geographically close, it differs from H. floridana in having serration on the upper edge of the major teeth of simple chaetae, relatively shorter dorsal cirri, and a distinct mode of life. Haplosyllides floridana lives as an endosimbiont of Xetospongia muta, H. aberrans comb. nov. as a facultative parasite of Platycaris latirostris, and H. ophiocomae sp. nov. as a commensal of Ophiocoma pumila and other brittle stars. The meaning of these associations is discussed in light of the available information. The remaining records of “Haplosyllides aberrans” from the Marshall Islands (associated with corals of the genus Heliopora) and from Brazil (among corals and calcareous algae) are considered as doubtful.

Two apparently unrelated groups of symbiotic annelids, Nautiliniellidae and Calamyzidae (Phyllodocida, Annelida), are a clade of derived chrysopetalid polychaetes

Nautiliniellidae Miura and Laubier, 1989 is a small family of marine polychaetes with 20 currently described species in 11 genera, most of which are known to live symbiotically in the mantle cavity of bivalves, mainly from cold seeps and hydrothermal vents, while Calamyzidae (Hartmann‐Schröder, 1971) including only one described species, Calamyzas amphictenicola Arwidsson 1932 lives as an ectoparasite on ampharetid polychaetes in Swedish waters. Nautiliniellidae and Calamyzidae have both been considered to belong to Phyllodocida, but the few phylogenetic studies including these taxa have found their positions unstable. The internal relationships within Nautiliniellidae are also poorly understood. Using molecular information from both nuclear and mitochondrial genes and morphological data we assessed the systematic placement of Nautiliniellidae (seven species; collected from Pacific hydrothermal vents and cold seeps and one from Atlantic waters) and Calamyzas amphictenicola. Our results show that C. amphictenicola and Nautiliniellidae formed a well‐supported clade that is nested within Chrysopetalidae, a free‐living group of polychaetes. The chrysopetalid genus Vigtorniella Kiseleva 1992; a bacterial mat grazer found at methane seeps, anoxic basins and whalefalls, formed a paraphyletic grade with respect to the Nautiliniellidae–Calamyzas clade. The internal relationships within the Nautiliniellidae–Calamyzas clade as well as the relationships with their hosts are also examined. As a result we synonymize Calamyzidae and Nautiliniellidae with Chrysopetalidae, with the last as the oldest available family‐group name. Within Chrysopetalidae we refer to the subfamilies Chrysopetalinae Ehlers 1864; Dysponetinae Aguado, Nygren & Rouse, herein; and Calamyzinae Hartmann‐Schröder, 1971. Calamyzinae contains C. amphictenicola, all taxa formerly in Nautiliniellidae, and the chrysopetalid genus Vigtorniella.

Contribution to the knowledge of Syllidae (Annelida, Phyllodocida) from Japan with descriptions of three new species

Abstract The study of a collection of Japanese Syllidae (Polychaeta) from 18 different intertidal samples yielded a total of 16 genera and 31 species. Three new species of Syllis Lamarck, 1818 from Japan are described. Syllis multiannulata sp. nov. is mainly characterised by its cylindrical broad body with annulated segments, weakly articulated antennae and cirri, dorsal cirri originating from two different levels, the presence of pre‐ and postchaetal parapodial lobes and the pharynx being shorter than the proventricle. Syllis pilosa sp. nov. is characterised by the presence of two marked ciliary bands per segment, elongated bidentate compound chaetae, and a very long pharynx and proventricle. Syllis rubicunda sp. nov. has a broad cylindrical body with distinct colour pattern, long and thick dorsal cirri, bidentate chaetae, and the pharyngeal tooth slightly removed from the anterior margin. Two species, revealing previously unreported morphological features, are also described and illustrated (Amblyosyllis speciosa Izuka, 1912 and Odontosyllis undecimdonta Imajima and Hartman, 1964). Moreover, one species belonging to the genus Pionosyllis Malmgren, 1867, is described, but will remain unnamed until additional material becomes available. An emended diagnosis for Alcyonosyllis Glasby and Watson, 2001 and a new combination, Alcyonosyllis exiliformis comb. nov. are proposed. The generic name, Trypanoseta, Imajima and Hartman, 1964 is proposed to replace Geminosyllis, Imajima, 1966 and the species, Trypanoseta sp. is described. Additionally, four new species to Japanese waters are herein reported: Eusyllis assimilis Marenzeller, 1867, Nudisyllis tinihekea Knox and Cameron, 1970, Paraehlersia ehlersiaformis (Augener, 1913), Branchiosyllis exilis (Gravier, 1900) and Syllis armil‐laris (Müller, 1771). Finally, Eusyllis habei Imajima 1966 and Odontosyllis fulgurans japonica Imajima, 1966 are considered synonymous with E. lamelligera Marion and Bobretzky, 1875 and O. fulgurans (Audouin & Milne Edwards, 1833) respectively.

A new genus and species of Syllidae (Annelida: Polychaeta) from Australia with unusual morphological characters and uncertain systematic position

ABSTRACT In this paper the description of Murrindisyllis kooromundroola, an enigmatic new genus and species of Syllidae (Polychaeta), is given. The new genus is characterized by having palps totally fused that are also fused with the prostomium, a single pair of eyes, a distinctly long, coiled median antenna, segments of the midbody with 2 or 3 chaetigers fused, dorsal cirri of the midbody smooth, ending in a webbed, “hand-like” structure, interiorly maintained by five rows of vacuolated cells, similar in shape to a frogs “foot,” simple chaetae on posterior segments produced by partial fusion of unidentate blades with the shafts, an unarmed pharynx, and a very long proventricle. These very unusual characters are unique among the syllids; webbed, “hand-like” structures on dorsal cirri are also unique among polychaetes. The combination of different characters assigned to different subfamilies and the presence of distinctive and unique features makes the systematic position of the new genus in the family Syllidae uncertain.

Syllidae (Annelida: Phyllodocida) from Lizard Island, Great Barrier Reef, Australia

Thirty species of the family Syllidae (Annelida, Phyllodocida) from Lizard Island have been identified. Three subfamilies (Eusyllinae, Exogoninae and Syllinae) are represented, as well as the currently unassigned genera Amblyosyllis and Westheidesyllis. The genus Trypanobia (Imajima & Hartman 1964), formerly considered a subgenus of Trypanosyllis, is elevated to genus rank. Seventeen species are new reports for Queensland and two are new species. Odontosyllis robustus n. sp. is characterized by a robust body and distinct colour pattern in live specimens consisting of lateral reddish-brown pigmentation on several segments, and bidentate, short and distally broad falcigers. Trypanobia cryptica n. sp. is found in association with sponges and characterized by a distinctive bright red colouration in live specimens, and one kind of simple chaeta with a short basal spur.

Revision of the genus Megasyllis (Annelida, Syllidae) with descriptions of four new species

The genus Megasyllis is herein reorganized excluding the size from the diagnosis, since it is not a characteristic of all the species of the genus. We provide here a taxonomic account of all known species and a key to species identification. Seven species are new combinations, and re-descriptions of the four latter are included: Megasyllis nipponica (Imajima, 1966) and M. multiannulata (Aguado, San Martin & Nishi, 2008) from Japan; Megasyllis procera (Hartman, 1965) from the Atlantic; Megasyllis pseudoheterosetosa (Boggemann & Westheide, 2004) from the Indian Ocean. Megasyllis glandulosa (Augener, 1913), from Australia; Megasyllis marquesensis (Monro, 1939) from the Marquesas Islands, Micronesia and Megasyllis subantennata (Hartmann-Schroder, 1984) from Australia. Four new species from the Pacific Ocean namely Megasyllis tigrina sp. nov., Megasyllis mariandreworum sp. nov. (both from Australia), Megasyllis chrissyae sp. nov. (from the Philippines) and Megasyllis eduardoi sp. nov. (from New Zealand) are described.

Contribution of Scanning Electron Microscope to the Study of Morphology, Biology, Reproduction, and Phylogeny of the Family Syllidae (Polychaeta)

Syllidae is a highly diverse family of the polychaetes (Annelida, Phyllodocida), with 72 described genera and almost 700 species (San Martin, 2003; Aguado & San Martin, 2009; Aguado et al., in press), and continuously new taxa are being described. They are small marine worms, usually of few mm long, although some species can reach up to 90 mm. Contrariwise to their small size, they are very complex, with a body exhibiting numerous structures, external and internal, some of them difficult to examine properly under light microscope, even using higher magnifications and Nomarsky system of polarized light. Description of most species before around the year 2000 was based only on examinations and drawings made with camera lucida under light microscopes. The use of SEM to study syllids is relatively recent, but produced the discover and descriptions of a number of new, unknown structures, or only incompletely known before, whose physiology and significance open a new field of research. The oldest SEM picture of a syllid is from 1980 in which Heacox showed the head of a Chaetosyllis stolon and a larval compound chaeta in a study of the life cycle of Syllis pulchra Berkeley & Berkeley, 1948 (Heacox, 1980); somewhat later, Pocklington & Hutchenson (1983) reported the viviparity of the interstitial species Parexogone hebes (Webster & Benedict, 1884) showing excellent and surprising SEM photographs of juveniles emerging through segmental apertures (probably nephridial pores) and also some characteristic crenulations of the ventral surface of female’s body after releasing juveniles; in the same year, Pawlick published the first SEM photos of general aspect of body, chaetae, and details of ciliation on the basis of dorsal cirri on the species Branchiosyllis oculata Ehlers, 1887. This is the first paper, in our knowledge, in which some previously overlooked structures were showed and described thanks to SEM; finally, Sarda & San Martin (1992) redescribed one species of syllid from East coast of USA, with some SEM pictures. However, few descriptions of new taxa with SEM and only few papers with SEM pictures of syllids were published during next years. Most of examinations came from our own relatively recent papers; one is the book “Fauna Iberica. Syllidae”, published in 2003, in which the 161 recorded species of the Iberian Peninsula are described and figured,

Phylogeny of Polycladida (Platyhelminthes) based on mtDNA data

A phylogenetic analysis of Polycladida based on two partial mitochondrial genes (cox1 and 16S) is provided. The analysis includes 30 polyclad terminals that represent species from the two taxa which traditionally divide the groups Cotylea and Acotylea. Our phylogenetic analyses produced a well-supported hypothesis that confirms the monophyly of Polycladida, as well as Acotylea and Cotylea. Within Acotylea, there are two lineages not highly supported: on one hand, Leptoplanoidea (excluding Hoploplana elisabelloi) and one Stylochoidea member (Pseudostylochus intermedius) (classification sensu Faubel, 1983, 1984), and on the other hand, Stylochoidea members together with Discocelis tigrina and H. elisabelloi. The genera Stylochus and Imogine are not monophyletic. Within Cotylea, Pseudocerotidae and Euryleptidae are monophyletic, though not highly supported, while Prosthiostomidae is not. Euryleptoidea is paraphyletic. The genera Pseudobiceros and Pseudoceros are monophyletic and highly supported. Our results suggest that, within Acotylea, the prostatoid organs of Discocelis may have been derived from a prostatic vesicle. The genus Hoploplana could be included in Stylochoidea. Within Cotylea, the common ancestor of Euryleptidae and Pseudocerotidae might have been an aposematic animal with tentacles.