Óscar García-Álvarez

Morphology of Falcidens vasconiensis (Mollusca, Caudofoveata, Chaetodermatidae), including a 3D reconstruction of the internal anatomy

The morphology and internal anatomy of the caudofoveate Falcidens vasconiensis Salvini-Plawen, 1996, are described and a 3D reconstruction of its anatomy is made with the program AVIZO 6.3.1. The detailed body shape, additional sclerite types, digestive system, and nervous system of F. vasconiensis are described for the first time. The nine specimens studied here were collected off the NW Iberian Peninsula between 150 and 600 m depth during the expeditions DIVA-Artabria I 2002 and 2003, Vertidos 2004, and A Selva 2008.

Solenogastres (Mollusca) from expeditions off the South Iberian Peninsula, with the description of a new species

The class Solenogastres (sensu Salvini-Plawen, 1967) includes approximately 270 described species, 30% of which can be found off the Atlantic and Mediterranean coasts of Europe. From the Iberian Peninsula, 36 species are known, and six are cited from the Southern Peninsula from Gorringe Bank to Cabo de Gata. The results of a study of a collection of 81 specimens are presented here. Solenogastres were collected from seafloors off the South Iberian Peninsula during three expeditions: DEEPER [Desarrollo de Estudios de Ecosistemas de Profundidad bajo un Enfoque interdisciplinar] 0409, INDEMARES [Inventario y designación en la Red Natura 2000 en áreas marinas del Estado Español]/Chica 0610–0211 and INDEMARES/Alborán 0911. Analysis of the collected solenogaster specimens resulted in the discovery of a new species, which is described here as Alexandromenia avempacensis sp. nov, along with the identification of four already known species: Unciherpia hirsuta Garcia-Alvarez, Salvini-Plawen and Urgorri, 2001, which had not been reported from the South of the Peninsula before and Neomenia carinata Tullberg, 1875, Anamenia gorgonophila (Kowalevsky, 1880) and Dorymenia sarsii (Koren & Danielssen, 1877), whose presence in this area was already known. New anatomical and ecological data regarding these species are also provided. The anatomical reconstruction of the anterior and posterior body ends of Neomenia carinata is presented in addition to a more detailed and extensive description of its copulatory spicules. A broader and more complete description of the sclerites of this species is also provided. The study of the habitus, hard parts and histological sections of Dorymenia sarsii points towards a synonymy between D. sarsii and D. tortilis Scheltema & Schander, 2000. Ecological data related to the accompanying fauna and the type of substratum for each species described is also provided. http://zoobank.org/urn:lsid:zoobank.org:pub:EA987A53-FF5D-463F-A072-0EA99BCDA129

Three new species of Pruvotinidae (Mollusca: Solenogastres) from Antarctica and NW Spain

The family Pruvotinidae (Solenogastres, Cavibelonia) includes thirty species of fifteen genera grouped in five subfamilies. These subfamilies are defined by the combination of the presence or absence of hollow hook-shaped sclerites, the presence or absence of a dorsopharyngeal gland and the type of ventrolateral foregut glandular organs: type A, type C or circumpharyngeal. In this paper, three new species of the family Pruvotinidae are described: Pruvotina artabra n. sp. and Gephyroherpia impar n. sp. from NW Spain, and Pruvotina manifesta n. sp. from Antarctic Peninsula. These new descriptions increase the global knowledge of Solenogastres biodiversity.

Urgorria compostelana gen. et sp. nov. (Mollusca, Solenogastres, Rhopalomeniidae), a new species from off Galicia, Northwest of Spain

Abstract During trawls taken on the Banco de Galicia (NW Spain) 21 specimens of a new Solenogastres: Urgorria compostelana gen. et sp. nov. were collected from a bottom dominated by the coral Madrepora oculata (Linnaeus, 1758). This new species is characterized by a middorsal cuticular keel; a pedal groove with two identical folds, reduced to one at the end of the body, entering the pallial cavity; it lacks a radula; by very small epithelial glandular organs of the foregut (Type C) and a midgut with a paired, dorsa-frontal caecum; one pair of seminal receptacles; unpaired genital orifice with a weak sphincter; one dorsoterminal sense organ. No copulatory spicules or respiratory folds.

Enhancement of the benthic communities around an isolated island in the Antarctic Ocean

Insular marine biotas are often richer in faunal diversity than those from the open sea in the same geographical region. The existence of particular island effects were tested under polar conditions by comparing infaunal benthic assemblages on Peter I Island with those of similar latitudes in the open ocean at the Bellingshausen Sea and also from the coast of the Antarctic Peninsula. Sampling was carried out aboard the R/V Hespérides during the expedition named BENTART-2003 from 24 January to 3 March 2003. Benthic samples were collected at 18 stations ranging from 90 to 2 044 m depth, using an USNEL-type box corer (BC) dredge. Representatives of 32 higher taxa of invertebrates were found. Univariate and multivariate analyses revealed various patterns in the data. First, significant differences in polychaete abundance were detected between the stations located in the open sea and the remaining sites (island plus mainland sites). Bivalve abundances were also distinct between island and mainland sampling sites. Sediment columns taken from the island seafloor exhibited the highest rate of bioturbation by the infauna. These findings confirm the model that islands develop distinct assemblages characterized by the enhancement of the benthic communities even in cold waters. Several abiotic factors were measured simultaneously at the seafloor and along the water column to investigate faunal distribution patterns. Significant correlations were found between the benthic assemblages and a combination of two environmental variables: “island effect” (measured as a categorical variable) and the redox state of sediments. Richer andmore complex benthic assemblages were found in Peter I Island’s sea bottom, whereas the more depauperate bottoms remained in the open sea.

Morphology of Prochaetoderma iberogallicum Salvini-Plawen, 1999 and Its Validity vs Prochaetoderma boucheti Scheltema & Ivanov, 2000

Prochaetoderma Thiele, 1902 is a genus of the class Caudofoveata under constant review, with several classifications and synonymizations of species. This genus is represented off the Iberian Peninsula by seven species, among which Prochaetoderma iberogallicum Salvini-Plawen (Iberus 17(2):77–84, 1999) and Prochaetoderma boucheti Scheltema and Ivanov (J Molluscan Stud 66(3):313-362, 2000) can be found. Both species are anatomically very similar and difficult to differentiate. Thanks to the study of new specimens collected in several oceanographic expeditions carried out off Galicia (NW Iberian Peninsula) and their comparison with the type series of both species, their taxonomical status is clarified and their anatomical study is also completed in terms of body morphology, buccal shield and typology of sclerites.

New data and 3D reconstruction of four species of Pruvotinidae (Mollusca: Solenogastres) from the NW Iberian peninsula

The family Pruvotinidae (Mollusca, Solenogastres, Cavibelonia) includes 34 species, six of which are present in hard bottoms off Galicia (NW Iberian Peninsula). In this study, three-dimensional (3D) anatomical reconstruction techniques were applied for the study of four species of the family present in Galician waters: Pruvotina artabra, Gephyroherpia impar, Luitfriedia minuta and Unciherpia hirsuta. Histology and 3D rendering in this study were carried out with Avizo 6.3 software and micro-computed tomography (micro-CT). New morphological and anatomical data are provided. The 3D reconstruction techniques used, which are based on histological sections, offer a slightly distorted view of the anatomy, but allow a better understanding of the relative situation of the organs. Micro-CT provides less information than histological reconstruction, but offers an excellent 3D anatomical view and allows the specimens to be preserved intact. With the new specimens collected, new data on their distribution and bathymetry are provided.

The habitus of Scutopus robustus Salvini-Plawen, 1970 (Caudofoveata, Limifossoridae), a rare mollusc from the NW Iberian Peninsula

Caudofoveata are vermiform, aplacophoran molluscs with reduced foot and a mantle covered with calcareous sclerites. Most Caudofoveata live at great depths mainly burrowing in muddy bottoms. They are usually damaged during their collection, thus the iconography available is incomplete, except for the patterns of the sclerites. A sample of Scutopus robustus was collected during the oceanographic expedition MASPROGAL 2013, carried out by the EBMG-USC, on the bottoms of polymetallic nodules and corals of the NW Iberian Peninsula at a depth of 600–700 m (43°48,000’N, 8°51,760’W). S. robustus is a rare species recorded for the first time in this geographic area, which confirms the suspicions of Salvini-Plawen and Garcia-Alvarez (2014) about its presence off the Iberian Peninsula; so far, it has only been found off Norway, Iceland, northern England, southwest Ireland and the western Mediterranean Sea (Salvini-Plawen 1970; Ivanov and Scheltema 2001, Salvini-Plawen and Garcia-Alvarez 2014). Specimen: 5 mm long × 0.25–0.5 mm wide. White in 70% ethanol. Postoral buccal shield slightly flanking the mouth. Three body regions (Fig. 1a): anterium, trunk and tassel, covered in sclerites lying longitudinally on the mantle. Anterium (Fig. 1b), with flat, smooth, lanceolate sclerites (40–70 μm long × 15–30 μm wide) and truncated base (Fig. 1e, f). Trunk narrowing in its medial region (Fig. 1c), with two types of sclerites: first type lanceolate (80–130 × 25–45 μm) with smooth waist, truncated base with slight notch and reinforced apical end of the blade (Fig. 1g–j) on the first part of the trunk; second type (100–150 × 20–50 μm) like the first but with a round base (Fig. 1k, l) at the end of the trunk. Tassel bell-shaped (Fig. 1d) with two types of sclerites: first type lanceolate (150–200 × 30–40 μm) with slight waist and round base longer than the blade (Fig. 1m); second type acicular (180–220 × 10–15 μm) and smooth (Fig. 1n). The iconography of S. robustus is scarce, and only two low-quality photographs of the habitus and some drawings of the sclerites are known (Salvini-Plawen 1970, 1972, 1975). The detailed photographs of the habitus and sclerites under and optical microscope and SEM presented in this paper are the first for this species. The studied specimen differs from those already described (Salvini-Plawen 1970, 1972, 1975), as the small, triangular sclerites described from the anterior part were not observed, probably due to the strong contraction of the anterior part, and the acicular sclerites of the tassel are longer than those of previous descriptions. The fact that the trunk Communicated by P. Martinez Arbizu

Description of the juvenile habitus of Hedylopsis spiculifera (Kowalevsky, 1901) (Heterobranchia; Acochlidia)

Samples were collected in amphioxus sand at the Ría de Ferrol (Galicia, NW Iberian Peninsula): St 1: 25 m (43°26’54^N; 008°20’40^W), three specimens (0.4-0.7 mm long). St 2: 14 m (43°27’59^N; 008°16’23^W), eight specimens 0.51.1 mm long. Also, 49 adult specimens 1.5-4.3 mm long were collected. Smallest specimen measuring 0.4 mm long and white. Head with a pair of flattened orbicular oral tentacles and a pair of cylindrical-conical rhinophores resembling the cephalic appendages of an adult. Large eyes. Visceral sac bulb-shaped with the rear half dorsoventrally flattened and subepidermal layer fully coated with monaxon spicules; dorsal spicules obliquely arranged, the lateral spicules of the visceral sac form a semicircular line bordering the sac and are crossed by others fanned out radially with the outer end surpassing the edge of the visceral sac (Fig. 1a, b, e). Cephalic spicules located in front of the eyes, particularly abundant at the end of the cephalic appendages, smaller than those of the visceral sac; they can be monoaxon, diaxon, triactine, and tetraxon. Long narrow foot, not exceeding the posterior edge of the visceral sac. Unlike adults, the juveniles observed never deform the visceral sac. Kowalevsky (1901) described Hedylopsis spiculifera (Kowalevsky, 1901) from the Sea of Marmara and the Aegean Sea and Odhner (1937) described Hedylopsis suecica Odhner, 1937, from Kristineberg (Sweden), thus considered them as distinct species. Wawra (1989), Sommerfeldt and Schrödl (2005), and other authors established their synonymy based on the similarities among various anatomical characters and also supported by molecular markers in specimens from the Atlantic Ocean and the Mediterranean Sea. However, the specimens studied here, both juvenile and adult, have anatomical variations in the visceral sac, foot, and cephalic tentacles according to age and size. Thus, the length of the visceral sac increases in relation to its foot length according to age; the visceral sac changes from an undeformable flattened bulb shape in juveniles to an elongated, almost circular section and very deformable shape in adults; the rhinophores fluctuate from cylinder-conical in juveniles to digitiform in adults and the orbicular oral tentacles in juveniles tend to bend in adults. These variations lead to different appearances and shapes in specimens according to their age and length, which would explain the different habitus described for Hedylopsis spiculifera and Hedylopsis suecica in the scientific literature. Communicated by P. Martinez Arbizu