Julio Parapar

Growth at moult and moulting seasonality of the spider crab, Maja squinado (Herbst) (Decapoda: Majidae) in experimental conditions: implications for juvenile life history

Abstract Prepubertal growth (moult size increment and duration of the intermoult period) and the seasonality of moulting in the spider crab Maja squinado from the southern coast of Galicia (NW Spain) were analyzed under experimental conditions (laboratory and extensive culture). Two annual moult periods were observed; the first corresponded to the prepubertal moults that take place in spring (reaching their peak at the end of March and in April), and the second to the pubertal (terminal) moult in summer during which time the animals reach morphometric maturity. The peak for the terminal moults within the population took place in June in the experiment under extensive culture conditions and in July and August in the laboratory and in the field, where the maximum annual temperatures were lower and occurred later (17–19 °C in August and September) than in the former experiment (21–22 °C in July). The modal number of annual moults per crab was 2, and ranged between 1 and 3. The number of annual moults decreased with the size of the animal at the beginning of the moulting season, and the animals delayed ecdysis in accordance with body size (there was a significant positive correlation between moulting date and body size within each of the two periods). There were no significant differences between males and females in moulting seasonality. In the laboratory, the duration of the intermoult period prior to the pubertal moult was estimated to be 104 days, and for the prepubertal moult it was 85 days. For specimens between 60 and 130 mm carapace length (CL), the moult size increment was estimated to be an average of 29 mm CL, which constitutes an average of 32% of the pre-ecdysial size. There were no significant differences in the moult increment between sexes or between the laboratory and extensive culture experiments. There were however significant differences between the pubertal and non-puberty moults (27 and 36%, respectively). This was due to the larger sizes of the prepubertal animals, and to the negative correlation between body size and the percentage moult increment (the absolute moult size increment was positively correlated with CL). The samplings carried out in juvenile habitats in shallow areas in the outer part of the Ria de Arousa (Galicia, NW Spain) in summer and winter confirm these experimental results. The body size and intermoult and maturity stages of the animals caught indicate that most of the juveniles (mean CL ≈ 110 mm) carried out the terminal moult in summer and had moult increments similar to those in the experimental conditions (mean body size of postmoult mature animals was aproximately 140 mm). In winter, however, the population was mainly composed of juveniles in intermoult.

Oweniidae (Annelida, Polychaeta) from Icelandic waters, collected by the BIOICE project, with a description of Myrioglobula islandica n. sp

Based on material collected during the BIOICE project off Iceland, the taxonomy and distribution of six species of polychaetous annelids belonging to the family Oweniidae are reviewed. Three species were previously reported in the area: Owenia fusiformis Delle Chiaje, Myriochele heeri Malmgren and Galathowenia oculata (Zaks); two are new to Icelandic waters: G. fragilis (Nilsen & Holthe) and Myriochele danielsseni Hansen, and one is new to science: Myrioglobula islandica, which is described and compared with Myrioglobula antarctica Hartman and Myrioglobula japonica Imajima & Morita. Several body characters with a high taxonomic value in oweniids were reviewed under the scanning electron microscope. In G. fragilis, the presence of an anteroventral structure, possibly related to tube construction, is presented, as well as its original description, proposed to be emended, due to the confirmation of a hook-shaped variability over the length of the body. The distribution of each species off Iceland was evaluated and two patterns were defined: O. cf. fusiformis and G. oculata were mainly found in sublittoral (<200 m) cold waters off the north coast, while G. fragilis and Myriochele heeri were found in a wide range of depth and temperatures all around Iceland. A key to the species of the family Oweniidae recorded in Icelandic waters is provided.

“Sedentary” polychaetes of the Livingston Island shelf (South Shetlands, Antarctica), with the description of a new species

Abstract The taxonomic results of examining the “sedentary” families of polychaetes collected during the Spanish cruise “Bentart 94” off Livingston Island, South Shetland Islands, Antarctica, are presented. Most of the identified species are endemic to Antarctic and sub-Antarctic areas, but some cosmopolitan species are also present. A total of 4,022 specimens have been examined, belonging to 44 species, 42 genera and 15 families. Maldanidae and Terebellidae were the most important families in number of species, and Asychis amphiglypta, Maldane sarsi antarctica and Amphitrite kerguelensis in number of individuals. Melinna arnaudi, a new species belonging to the family Ampharetidae, is described, and Phisia rubrolineata and Aricidea (Allia) oculata are recorded for the first time since their original description.

Distribution and diversity of the Opheliidae (Annelida, Polychaeta) on the continental shelf and slope of Iceland, with a review of the genus Ophelina in northeast Atlantic waters and description of two new species

The diversity, taxonomy and distribution of the Opheliidae (Annelida: Polychaeta) in Icelandic waters is reviewed based on material collected during the BIOICE project. Nine opheliid species are recorded from Iceland; of these, three were previously reported in the area (Ophelia limacina, Ophelina cylindricaudata and O. acuminata), four are new for Icelandic waters (Ammotrypanella cf. arctica, Ophelina abranchiata, O. helgolandica and Tachytrypane jeffreisii), and two are new to science. Ophelina basicirra sp. nov. is distinguished by having a narrow anal tube with one short proximal anal cirrus in ventral position. Ophelina bowitzi sp. nov. is characterized by the small size of its anterior branchiae, which become larger in the middle and posterior body regions, and by an upwardly bent anal tube that is wide at the base and narrowing distally. The genera Euzonus, Armandia and Polyophthalmus are not represented in the BIOICE samples. The distribution of each species off Iceland is presented; one species is restricted to shallow waters of northwestern fjords, three species are found south of the GIF Ridge, and five species are circumicelandic. Several body characters with taxonomic relevance in some species are reviewed based on SEM images. Furthermore, as a first step towards a future revision of the genus Ophelina Örsted 1843 in North Atlantic waters, the status of each species originally described or subsequently reported from the area is commented on, and a key to the currently valid species is presented. Ophelina longicephala Hartmann-Schröder, 1977, formerly a subspecies of O. delapidans (Kinberg, 1866), is raised to species status.

The genera Myriochele and Myrioglobula (Polychaeta, Oweniidae) in Icelandic waters with the revision of type material of Myriochele heeri Malmgren, 1867, and the description of a new species

Based on the study of specimens previously identified as Myriochele heeri Malmgren, 1867 (Polychaeta, Oweniidae) in Icelandic waters collected during the BIOICE project, a redescription of this taxon is presented, a Pacific species—Myriochele olgae Blake, 2000—is reported, and one new species is described: Myrioglobula malmgreni sp. nov. Myriochele heeri is characterized by three short anterior uniramous chaetigers of similar length. The revision of the type series of M. heeri showed that the length of the anterior chaetigers and the chaetal composition is variable in the different specimens, thus demonstrating that more than one species is involved. Complementary anatomical (prostomial, foregut, and peristomial ciliary fields, ventral pharyngeal organ) and biological (food composition, tube ornamentation, body regeneration) observations from selected specimens are provided. Additions to the original description of Myrioglobula islandica Parapar, 2003a and an updated key to the species of Oweniidae recorded in Arctic and East Atlantic Boreal waters are also presented. Aspects on geographical distribution and phylogeny of the family are also discussed.

Taxonomy and distribution of the genus Amphicteis (Polychaeta: Ampharetidae) collected by the BIOICE project in Icelandic waters

Based on material collected during the BIOICE project off Iceland, four species of polychaetous annelids belonging to the genus Amphicteis Grube, 1850 (Polychaeta: Ampharetidae) were found: Amphicteis gunneri, Amphicteis ninonae, Amphicteis vestis and Amphicteis wesenbergae sp. nov. The differences between A. gunneri and A. ninonae, two species usually confused in the literature, are reviewed. Amphicteis vestis is described from newly collected material and its taxonomy in relation to other ampharetid taxa with modified notopodia is discussed. Amphicteis wesenbergae sp. nov. is described; the new species is characterized by the presence of long, slender and evenly tapered paleae, and long dorsal cirri on thoracic and abdominal neuropodia. Several body characters with high value in Amphicteis taxonomy, particularly the dorsolateral protrusions of abdominal chaetigers called rudimentary notopodia, are reviewed using scanning electron microscopy. A key to species of the genus Amphicteis described or reported in European Boreo-Arctic waters is provided.

Sphaerodoridae (Annelida: Polychaeta) from the Bellingshausen Sea (Antarctica) with the description of two new species

The examination of polychaete collections obtained during the Spanish Bentart 2006 expedition to the Bellingshausen Sea (Antarctica) revealed the presence of several sphaerodorid species. In this work, species belonging to the genera Sphaerodorum Örsted, 1843, Ephesiella Chamberlin, 1919, Clavodorum Hartman and Fauchald, 1971 and Sphaerephesia Fauchald, 1972 are reported including two new species belonging to Sphaerodorum and Sphaerephesia, respectively. A specimen identified as Ephesiella sp. might also represent a new species but, due to its poor state of preservation, a formal description is not possible yet. Furthermore, Sphaerodoropsis polypapillata Hartmann-Schröder and Rosenfeldt, 1988 is transferred to the genus Clavodorum Hartman and Fauchald, 1971 after examination of the type series and specimens obtained from the Bellingshausen Sea.

Redescription of Terebellides stroemii (Polychaeta, Trichobranchidae) and designation of a neotype

Terebellides stroemii Sars, 1835, the type species of the genus, was originally described from the south-west coast of Norway. Over the past 170 plus years this species has been reported from around the world often without a detailed description; in some cases, schematic illustrations of the anterior end with the distinctive branchiae were given. Identifications were likely based mainly on the branchiae consisting of 4–5 lobes but recent work has shown that this character alone has led to misidentifications and confusion of a number of morphologically similar species. Michael Sars (1835) did not designate type specimens for this species. In order to provide an accurate definition of the genus it is necessary to redescribe and characterize the type species including the designation of a neotype. This will provide a baseline against which the potentially undescribed sibling species in the area can be compared and fully described. A large collection of specimens identified as T. stroemii

Polychaetes of the genus Ampharete (Polychaeta: Ampharetidae) collected in Icelandic waters during the BIOICE project

Based on material collected during the BIOICE project off Iceland, the taxonomy and distribution of eight species of polychaetous annelids belonging to the genus Ampharete (Polychaeta: Ampharetidae) are reviewed. Five of these species were previously reported in the area: Ampharete acutifrons, Ampharete borealis, Ampharete finmarchica, Ampharete octocirrata and Ampharete petersenae; two are new to Icelandic waters: Ampharetebaltica and Ampharete lindstroemi; and one is new to science: Ampharete villenai sp. nov. A. petersenae was found for the first time after the original description and is redescribed. A. villenai sp. nov. is primarily characterized by the size, shape and disposition of the paleae, a special kind of chaetae located on the first body chaetiger. Several body characters of high taxonomic relevance in Ampharetidae are reviewed under the SEM. The distribution of each species off the coast of Iceland and a key to all species recorded in European Boreo-Arctic waters is provided.

Redescription of Terebellides kerguelensis stat. nov. (Polychaeta: Trichobranchidae) from Antarctic and subantarctic waters

During the Spanish Antarctic expeditions “Bentart” 1994, 1995 and 2003, a number of trichobranchid (Annelida: Polychaeta) specimens were collected and identified initially as Terebellides stroemii kerguelensis McIntosh, 1885, the only known species of the genus widely recognised as valid in Antarctic waters. In the framework of a worldwide revision of the genus Terebellides, a reconsideration of the taxonomic status of this subspecies of the boreal Terebellides stroemii Sars, 1835 is done through the examination of the syntypes of T. s. kerguelensis compared with recent descriptions of the nominal species from Norwegian waters and material from Icelandic waters. Thus, T. s. kerguelensis is regarded as a valid species, T. kerguelensis stat. nov., and redescribed designating a lectotype and paralectotypes. The species is mainly characterised by the presence of an anterior branchial extension (fifth lobe), lateral lappets in five anterior thoracic chaetigers, segmental organs in chaetigers 1, 4 and 5, and first thoracic acicular neurochaetae sharply bent with pointed tips. The biological role of the segmental organs, the presence and disposition of cilia in branchial lamellae and the finding of new structures located in dorsal part of thoracic notopodia are discussed.