Vasily I. Radashevsky

Polydora uncinata (Polychaeta: Spionidae) in Chile: an accidental transportation across the Pacific

A Polydora species was found boring in shells of the abalone Haliotis discus hannai cultivated in land-based tanks in Coquimbo, Chile. Spionid polychaetes of Polydora and related genera have been reported from Chile but no worms similar to those found in abalone have been described. The abalone pest corresponds in morphology to Polydora uncinata Sato-Okoshi, 1998, a shell-boring species which was originally described from Japan and never reported from outside the country. It is suggested that occurrence of the species in Chile resulted from its accidental transportation from Japan. Adult worms were most likely transported to Coquimbo with imported abalone brood stock. Prevalence of abalone infestation by worms in Coquimbo varied substantially among cultivation tanks, reaching values as high as 98.8%. Up to 42 worms were found in one shell. The worms often caused formation of nacreous blisters which covered up to 50% of the inner shell surface. Egg capsules with developing larvae were present in female burrows. Larval development was entirely lecithotrophic, with larvae feeding on numerous nurse eggs, staying inside egg capsules until 16–17-segment stage and hatching shortly before metamorphosis. Polydora uncinata is redescribed based on individuals from Coquimbo to alert zoologists in case of accidental release of worms into Chilean coastal waters. Regardless of how the species was transported to Chile, its release to the natural ecosystem may have negative unforeseen impacts on the native fauna.

Genetic differences between two sibling species of the Polydora ciliata complex (Polychaeta: Spionidae)

Abstract Two sympatric sibling Polydora species, P . cf. ciliata (Johnston) boring into calcareous substrata and P. limicola Annenkova inhabiting mud tubes in fouling on bottoms of ships, were investigated through their allozyme variations by means of starch gel electrophoresis. A survey of 18 enzyme systems comprising 27 loci showed a lack of common alleles at 10 loci: Fdh, Fum, Got-2, Gpi-1, Gpt, Lap, Mdh-1, Mdh-2, Sdh, Sod and duplication of alkaline phosphatase gene in P . cf. ciliata and glucose phosphate isomerase gene in P. limicola . Our genetic data indicate that we have two good congeneric Polydora species distinguishable by their allozyme variation and different in their ecology. The values of Neis indices of genetic identity and standard genetic distance between the two species are I = 0.317 and D = 1.149. At the same time, the long-standing systematic ciliata—limicola problem remains unsolved and requires further investigations because the well-known “boring” species, P. ciliata was first described as living in fine, soft mud.

The morphology of two sibling sympatric Polydora species (Polychaeta: Spionidae) from the Sea of Japan

Two sympatric species earlier differentiated by means of starch gel electrophoresis within Polydora cf. ciliata from the Sea of Japan are here identified and their adult and gamete morphology are described and illustrated. One species bores into various shells and coralline algae while the other bores only into gastropod shells occupied by hermit crabs. Both species have the prostomium anteriorly incised to rounded, 0–4 eyes, the caruncle extending to the end of chaetiger 2, heavy falcate spines of chaetiger 5 with a lateral tooth, branchiae beginning on chaetiger 7, and the pygidium disc-like to cup-shaped with a dorsal gap to only an incision. Males of the two species differ in aggregations of spermatids. The more opportunistic borer, which occurs in a greater number of hosts, always has 8-cell-aggregations of spermatids. These worms are here referred to as P. calcarea . The other species, in which spermatids are always interconnected in tetrads, is here described as a new one, P. manchenkoi sp. nov. The two species also differ in that prominent brownish-yellow pigment appears on the posterior segments after fixation in formaldehyde in P. manchenkoi sp. nov. but not in P. calcarea . It is suggested that spermatid aggregates and spermatozoan morphology be included in future polychaete descriptions when possible.

GONADAL STATE OF THE OYSTER CRASSOSTREA ANGULATA CULTIVATED IN TAIWAN

ABSTRACT Reproductive health of the common cupped oyster Crassostrea angulata cultivated in Taiwan was estimated through histological examination and semiquantitative analysis of their gonads. Oysters were collected in 4 aquaculture sites along the western coast of Taiwan (Hsiangshan, Chiku, Beimen, and Putai), where the major sources of industrial pollution are located, and off Penghu Island in the southern part of the Taiwan Strait, a comparatively clean resort area. The oysters from Hsiangshan had the lowest gonad maturity index (GMI) and the highest index of pathological alterations (IPA; P < 0.001); greater numbers of oysters with undifferentiated gonads (30%) and a green mantle (66.7%) were also present here. Most prominent gonad pathologies were atresia of oocytes and hemocytic infiltration of gonadal tissue. Oysters from Penghu had the highest GMI and the lowest IPA, whereas oysters from Chiku, Beimen, and Putai had intermediate values. Soft tissues of oysters from Hsiangshan contained 3,761.0 ± 1,201.0 µg/g dry weight Cu, 3,761.0 ± 1,201.0 µg/g Zn, and 1.5 ± 0.06 µg/g Cd, which is about 17 times, 3 times, and 1.5 times greater than the corresponding metal concentrations in the tissues of oysters from Penghu. Gametogenesis impairment in oysters cultivated in Taiwan are likely caused by environmental pollution.

Tungsten and other heavy metal contamination in aquatic environments receiving wastewater from semiconductor manufacturing

Through analyses of water and sediments, we investigate tungsten and 14 other heavy metals in a stream receiving treated effluents from a semiconductor manufacturer-clustered science park in Taiwan. Treated effluents account for ∼ 50% of total annual river discharge and <1% of total sediment discharge. Dissolved tungsten concentrations in the effluents abnormally reach 400 μg/L, as compared to the world river average concentration of <0.1 μg/L. Particulate tungsten concentrations are up to 300 μg/g in suspended and deposited sediments, and the corresponding enrichment factors are three orders of magnitude higher than average crust composition. Surprisingly, the estimated amount of tungsten exported to the adjacent ocean is 23.5 t/yr, which can approximate the amount from the Yangtze River should it be unpolluted. This study highlights the urgency of investigating the biological effect of such contamination.

Genetic differences between two allopatric sibling species of the genus Polydora (Polychaeta: Spionidae) from the West Pacific

Abstract Polydora vulgaris Mohammad, 1972, a commensal borer of the oysters Pinctada margaritifera and Hyotissa hyotis from the South China Sea, was investigated by means of starch gel electrophoresis. Polydora vulgaris and the allopatric sibling Polydora glycymerica Radashevsky, 1993, a commensal borer of the bivalve Glycymeris yessoensis from the Sea of Japan, were compared with respect to their allozymic variation and number of isozyme loci. Interspecific differences in the number of gene loci coding for three enzymes: alanopine dehydrogenase, glucose-6-phosphate isomerase and l -iditol dehydrogenase were revealed suggesting that we are dealing with two valid species. Two different modes of origin duplicate loci in polydorids are dicussed—polyploidization and regional gene duplication. The use of gene number as a character for discriminating between morphologically indistinguishable allopatric polydorid taxa is outlined.

Espécies de Scolelepis (Polychaeta, Spionidae) de praias do Estado do Rio de Janeiro, Brasil

Spionidae is one of the most abundant and diverse taxa among polychaetes. Scolelepis is one of the most abundant genus in shallow waters being widely distributed worldwide. Seven Scolelepis species have been reported to the Brazilian coast, but their taxonomy should be verified owing to a discussion on correct species identification and the possibility of being a species complex. The aim of this study was to make an inventory the species of the genus Scolelepis found in the beaches of Rio de Janeiro State, Brazil. Two species were found: S. chiliensis, very abundant and occurring in several beaches and S. goodbodyi with a more restricted distribution.

Genetic differences between two sibling sympatric Dipolydora species (Polychaeta: Spionidae) from the Sea of Japan, and a new species description

A Dipolydora species (Polychaeta: Spionidae) was found in mud tubes attached to the larger tubes of the chaetopterid polychaete Chaetopterus cautus in Peter the Great Bay of the Sea of Japan. The worms were close in morphology to D. carunculata , a borer of various calcareous substrata and sponges described earlier from the same area. The chaetopterid-associated tube-building individuals usually differed from shell-boring individuals by the presence of black pigmentation on palps. However, some of them were not pigmented and appeared almost identical to D. carunculata . Isozymes of the tube-building and shell-boring individuals were compared using starch gel electrophoresis. Two of 16 studied isozyme loci proved diagnostic and unequivocally demonstrated the presence of two distinct species. The chaetopterid-associated individuals are described here as a new species, D. melanopalpa . Unbiased Neis genetic distance between D. melanopalpa and D. carunculata ( D =0·949) as well as the level of intraspecific genetic variation in either of them ( D. melanopalpa , H e =0·206±0·054; D. carunculata , H e =0·239±0·044) are high and comparable to those of other electrophoretically studied polydorids. In contrast to other examined polydorids, D. carunculata and D. melanopalpa have the same numbers of expressed isozyme loci.

Morphology and biology of a new Rhynchospio species (Annelida: Spionidae) from the South China Sea, Vietnam, with the review of Rhynchospio taxa

Adults of a new spionid polychaete, Rhynchospio nhatrangi, inhabit sandy tubes on muddy sand intertidal flats in an estuary of Nha Trang Bay, southern Vietnam. The worms are up to 8 mm long and 0.5 mm wide for 55 chaetigers. They are unique among spionids in the changes in the arrangement of hooks during ontogenesis: first development of tridentate hooks in neuropodia from chaetiger 10, later loss of hooks in chaetiger 10, and replacement of tridentate hooks by heavy unidentate hooks in neuropodia of chaetigers 11–14. Adults are simultaneous hermaphrodites having sperm in chaetigers 11–14 and oocytes from chaetiger 15 to 23–33. Spermatozoa are introsperm, about 300 µm long. Oocytes are about 120 µm in diameter, with a thin and smooth envelope. Fertilization and early larval development occur in a hatchery formed by elongated dorsal capillaries on the posterior chaetigers. Larvae escape from the hatchery probably when they have developed four chaetigers and then continue development in seawater, feeding on the plankton. When larvae have grown to 14–15 chaetigers, they likely undergo gradual metamorphosis and settle on the bottom. Metameric nuchal organs, glandular pouches in neuropodia, metanephridial segmental organs, hermaphroditism, sperm, and early larval morphology are described here for the first time for Rhynchospio species. An identification key is provided to eight currently recognized Rhynchospio species.

Morphology and biology of Polydora rickettsi (Polychaeta: Spionidae) from Chile

Abstract The spionid polychaete Polydora rickettsi is primarily a borer in various calcareous substrata in the eastern Pacific. Redescription of the species from the type locality in Mexico is required to better understand its distribution. In Chile, females and males become mature after growth to c. 60 segments. Sex allocation in the population is close to 1:1. Gametes develop along segmental blood vessels in middle segments. Spermatogonia proliferate in temporary testes and the rest of spermatogenesis occurs in the coelomic cavity. On their release through metanephridial segmental organs, longheaded spermatozoa are packed in filiform spermatophores. Females store inactive spermatozoa in paired seminal receptacles on the dorsal side of fertile segments. Oogenesis is mostly intraovarian. Females deposit up to 4150 eggs into 65 capsules which are joined to each other in a string. Each egg capsule is attached by two stalks to the inner wall of the burrow and contains up to 65 eggs c. 95 μm in diameter. Most eggs give rise to larvae which develop inside egg capsules until the 3‐segment stage, then hatch and continue development in sea water, feeding on plankton. Fully developed 17–18‐seg‐ment larvae are able to settle and metamorphose. They have one pair of phaosomes and three pairs of black eyes on the prostomium, provisional proto‐nephridia in segments 1 and 2, paired dorsal melanophores from segment 3 onwards, lateral melanophores on segment 2 and from segment 10 onwards, yellow pigment in the wall of posterior gut, glandular pouches from segment 6 onwards, short branchiae on segments 7–11, gastrotrochs on segments 3, 5, 7, 10, 13, 15, and 17, one pair of provisional modified bristles and two or three falcate spines of a “quasi‐adult” kind in segment 5. Development of the “quasi‐adult” spines is described for the first time in polydorid larvae.