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A new Asterocheres (Copepoda, Siphonostomatoida) symbiont of the sea star Nidorellia armata (Gray, 1840) (Echinodermata, Asteroidea) in the Eastern Tropical Pacific
Abstract
A new species of the diverse and widely distributed symbiotic copepod genus Asterocheres is described from the sea star Nidorellia armata (Gray, 1840) in Mexican waters of the Eastern Tropical Pacific. The new species resembles various other congeners by sharing several characters including: (1) a siphon extending to the intersection of the maxilliped, (2) a 21-segmented antennule, and (3) a 2-segmented mandible palp. It can be distinguished by the unique structure and ornamentation of the maxilla, the armature and proportions of the fifth leg, and its body shape.
This is the first documented record of Asterocheres from the Mexican Pacific and the first finding of a symbiotic copepod on this sea star host. Males, ovigerous females and copepodites were recorded from the host, thus suggesting a well-established symbiotic association. It is likely that copepods feed on the host’s tegument. Further studies will be needed to assess the reproductive traits and seasonality of this copepod as a symbiont.
Two new genera and four new species of siphonostomatoid copepods of the family Asterocheridae associated with sponges are described from the Korean East Sea (Sea of Japan). These new copepods are distinguishable from related genera and species by their diagnostic morphological characters as follows: Amalomyzon elongatum n. gen. n. sp. bears an elongated body, two-segmented rami of legs 2, a uniramous leg 3 with two-segmented exopod, and a rudimentary leg 4 represented by a lobe. Dokdocheres rotundus n. gen. n. sp. has an 18-segmented female antennule, a two-segmented endopod of antenna, and unusual setations of swimming legs, including three spines plus four setae on the third exopodal segment of legs 2–4. Asterocheres banderaae n. sp. has no inner coxal seta on leg 1 or 4, but has two strong, sexually dimorphic inner spines on the second endopodal segment of male leg 3. Scottocheres nesobius n. sp. bears elongate female caudal rami about six times longer than wide, a 17-segmented female antennule, and two spines plus four setae on the third exopodal segment of leg 1.
Los invertebrados conforman el grupo más abundante y diverso entre los animales marinos, no obstante, son menos apreciados y estudiados en comparación con los vertebrados. En el Pacífico sur de México, formado por los estados de Guerrero, Oaxaca y Chiapas, está comprobada la enorme diversidad biológica terrestre que contiene; no es así el caso sobre su biodiversidad marina, en especial sobre los invertebrados marinos, cuya información parece ser escasa o muy dispersa.
Con la intención de subsanar esta falta de información y cambiar la percepción sobre la biodiversidad de los invertebrados marinos del Pacífico sur de México, se preparó esta obra colectiva, la cual está compuesta de 10 capítulos realizados por especialistas. El inventario completo incluye casi 2,600 especies de invertebrados marinos registrados en la región, pertenecientes a 16 filos. La información de cada uno de los registros, su presencia en cada estado del Pacífico sur de México, así como su distribución batimétrica, entre otros datos de interés, puede ser consultada en cada uno de los capítulos respectivos.
This review of copepod crustaceans associated with reef-dwelling cnidarians, sponges and echinoderms of the Greater Caribbean is based on published records, systematically arranged by the classification of the symbiotic copepods and their hosts, sampling sites, coordinates, depth and date of sampling, literature sources, and three recent surveys (Cuba, St. Eustatius in the Eastern Caribbean and Curaçao in the Southern Caribbean). This resulted in totals of 532 records of 115 species of symbiotic copepods (47 gen-era, 17 families, three orders) hosted by 80 species of invertebrates, representing scleractinians (47%), octocorals (9%), echinoderms (3%), and sponges (1%). Among ten Caribbean ecoregions, the Greater Antilles (with 64 species of symbiotic copepods) as well as the Southern and Eastern Caribbean (with 46 and 17 species of copepods, respectively) are the most studied and best represented, whereas only six species of copepods are known from Bermuda, one from Southwestern Caribbean and none from the Gulf of Mexico. The absence of poecilostomatoid copepods (Anchimolgidae, Rhynchomolgidae and Xarifidae) on Caribbean stony corals as noted by Stock (1988) is confirmed. The results indicate that the diversity and ecology of Caribbean symbiotic copepods are still poorly investigated.
Abstract.—In symbiotic copepods, most naupliar stages are typically planktonic, playing
a primary role in dispersal, while the first copepodid usually represents the infective
stage. Later copepodid stages, including adults, are associated with host organisms.
Many symbiotic copepods have abbreviated life cycles, with a reduced number
of naupliar stages and two different feeding habits. These patterns are presumably related
to distinct life cycles strategies. Exceptional cases are exemplified by members of
the Monstrillidae and Thaumatopsyllidae, both of which are protelean parasites, with
infective nauplii and non-feeding planktonic adults. In the Caligidae, the life cycle follows
a generalized pattern, but adults of many species like Caligus undulatus seem to
exhibit a dual mode of life involving host switching. Adults leaving the first host become
temporarily planktonic before attaching to the final host. This dual mode of life
is also found in adults of the Ergasilidae. Abbreviation of the planktonic phase is characteristic
for some symbiotic taxa, thus suggesting that they have evolved to become
highly efficient in locating and infecting new hosts without needing long-distance larval
dispersal. The life cycle of copepods associated with zooplankters is also briefly
reviewed. Zooplankters are clearly less used as hosts by copepods than benthic invertebrates.
It is likely that symbiotic copepods dynamically utilize planktonic phases in
their life cycle, thus maintaining the balance between dispersal, host location, reproduction,
and predator-avoidance strategies.
Twelve species of siphonostomatoid copepods mainly associated with marine invertebrates are recorded from Korean waters. Nine species are new to science: Arctopontius minutus n. sp., A. adelphus n. sp, and Dyspontius alatus n. sp. in the family Artotrogidae; Asterocheres horridus n. sp., A. cuspis n. sp., A. quadridens n. sp., Scottocheres mipoensis n. sp., Asteropontoides acutirostris n. sp. and Callomyzon macrocephalus n. gen. n. sp. in the family Asterocheridae. The new genus Callomyzon is distinguished from other genera in the family by having six setae on the third endopodal segment of leg 3, four spines and three setae on the third exopodal segment of leg 4 and three setae on the third endopodal segment of leg 4. Three new records of Korea, Asterocheres lilljeborgi Boeck, 1859 and A. simulans (T. Scott, 1898) in the Asterocheridae, and Parartotrogus arcticus T. and A. Scott, 1901 in the Cancerillidae are redescribed as the circum-Arctic species.
Dos especies de copépodos pertenecientes al género Asterocheres fueron halladas en recolectas recientes al norte de la provincia de Matanzas. Se describe la especie asociada a la esponja del género Callyspongia Duchassaing y Michelotti, 1864, como una nueva especie de copépodo sifonostomatoideo para la ciencia. Se discuten las diferencias más importantes entre esta especie y sus similares. Se informa, por primera vez, la presencia de A. crinoidicola asociada a un crinoideo del género Davidaster Hoggett y Rowe, 1986, en aguas del archipiélago cubano.
ABSTRACT
Two species of copepods belonging to the genus Asterocheres were found in recent collections in the North of Matanzas province. The one associated to the sponge of the genus Callyspongia Duchassaing y Michelotti, 1864 is described as a new species of siphonostomatoid copepod to science. The differences among the new specie and the more similar ones are also presented. A. crinoidicola, associated to a crinoid of the genus Davidaster Hoggett y Rowe, 1986 is recorded for the first time for the Cuban Archipelago.
Five new species of copepods associated with marine invertebrates are described from shallow water of the Pacific coast of Panama. They are Pseudomacrochiron pocilloporae n. sp., Acontiophorus panamensis n. sp. and Asterocheres urabensis n. sp. associated with the scleractinian coral Pocillopora damicornis (Linnaeus), Asterocheres pilosus n. sp. associated with the echinoid Eucidaris thouarsii (Valenciennes), and Asterocheres walteri n. sp. associated with the sea star Oreaster brevispinis.
Two new species of siphonostomatoid copepods, Asterocheres tubiporae n. sp. and Entomopsyllus stocki n. sp., associated with the stoloniferan coral Tubipora musica (Linnaeus) are described from Madagascar. Asterocheres tubiporae is characterized by the possession of a large posteroventral process on the caudal ramus and the elongated free segment of leg 5. Entomopsyllus stocki is readily distinguished from its congeners by the possession in the female of 15‐segmented antennule and three spines plus two setae on the third exopodal segment of leg 4.
Three new species of siphonostomatoid copepods belonging to the genus Asterocheres Boeck, 1859 are described. They were associated with sponges of the genera Niphates Duchassaing and Michelotti, 1864, and Callyspongia Duchassaing and Michelotti, 1864. Asterocheres paraboecki Johnsson, 1998 is recorded for the first time from Cuban archipelago.
The present paper reviews the material of three species of Asterocheres Boeck 1859 deposited in four different Zoological European museums as part of the ongoing taxonomical revision of this genus. Asterocheres sarsi Bandera & Conradi 2009, the species described by Sars in 1915 as Ascomyzon latum (Brady 1880) and lately recognized as a distinct species by Bandera and Conradi in 2009 is fully described in this paper from material collected by Sars in Norway in 1915 and deposited in The Natural History Museum of the University of Oslo. Asterocheres complexus Stock, 1960 which has been sometimes confused with A. sarsi is redescribed from material collected by Stock in France in 1959 and deposited in the Zoological Museum of the University of Amsterdam. Furthermore, a new species, previously misidentified as A. suberitis Gieisbrecht 1897, from the Norman`s collection of The Natural History Museum of London, is described as A. eugenioi, new species. These three species, A. complexus, A. eugenioi, and A. sarsi share the general appearance of body thanks to the pointed posterolateral angle of the epimeral area of somite bearing leg 3, sometimes slightly produced into backwardly directed processes, and somite bearing leg 4 largely concealed under somite bearing leg 3.
Three species of Asterocheres, including two new species, are reported as associates of sponges in shallow Antarctic water. Asterocheres spinosus sp. nov. has a combination of diagnostic features: mandibular palp is one-segmented, caudal ramus is 1.88 times as long as wide, antennule is 20-segmented in the female and 18-segmented in the male, urosome is spinulose, and legs 1 and 2 display weak sexual dimorphsims. In A. rai sp. nov., the body is large, 1.66 mm long in the female, the lateral margin of genital double-somite is smooth without setules or spinules, the exopod of antenna bears only a single seta, with two mucilaginous substances transformed from setae, and the third endopodal segment of leg 1 bears a prolonged distal process. A supplementary description is given for A. hirsutus Bandera, Conradi and López-González, 2005, recorded previously from the Antarctic.
Asterocheres flustrae n. sp. is described from Flustra foliacea L. (Bryozoa) found in the Kandalaksha Bay of the White Sea. This is the first siphonostomatoid copepod to be reported in association with a bryozoan. Distinctive features of the new species are: (1) a female with 21- and male with 18-segmented antennules; (2) five setae on the inner lobe of the maxillule with one much reduced; (3) an aesthetasc on the syncoxa of the maxilla; (4) a 6-segmented maxilliped with a distal claw; and (5) the armature of endopodal segments 2, 1, 1 and 1. Sexual dimorphism was observed not only on the antennules, but also for maxilliped and legs 16. By using SEM some new fine structures were revealed, including: one seta on each of antennulary segments 1 to 4, 6 and 8 with a nipple-like tip and an apical pore surrounded at its base by a circlet of cuticular denticles; a rostral region having a circular area ornamented with minute cuticular protuberances; and the labrum ornamented with fine hair-like setules on either side of its apex.
Copepoda is one of the most prominent higher taxa with almost 80 described species at deep-sea hydrothermal vents. The unique copepod family Dirivultidae with currently 50 described species is the most species rich invertebrate family at hydrothermal vents.
We reviewed the literature of Dirivultidae and provide a complete key to species, and map geographical and habitat specific distribution. In addition we discuss the ecology and origin of this family.
Dirivultidae are only present at deep-sea hydrothermal vents and along the axial summit trough of midocean ridges, with the exception of Dirivultus dentaneus found associated with Lamellibrachia species at 1125 m depth off southern California. To our current knowledge Dirivultidae are unknown from shallow-water vents, seeps, whale falls, and wood falls. They are a prominent part of all communities at vents and in certain habitat types (like sulfide chimneys colonized by pompei worms) they are the most abundant animals. They are free-living on hard substrate, mostly found in aggregations of various foundation species (e.g. alvinellids, vestimentiferans, and bivalves). Most dirivultid species colonize more than one habitat type. Dirivultids have a world-wide distribution, but most genera and species are endemic to a single biogeographic region. Their origin is unclear yet, but immigration from other deep-sea chemosynthetic habitats (stepping stone hypothesis) or from the deep-sea sediments seems unlikely, since Dirivultidae are unknown from these environments. Dirivultidae is the most species rich family and thus can be considered the most successful taxon at deep-sea vents.
Sea stars (Asteroidea) are invertebrates with remarkable importance in rocky and coral habitats as they occupy several levels in trophic webs, and many times act as top predators in these ecosystems. The taxonomic and biogeographic knowledge about this group in México is adequate, but there is still limited information on the ecology and functioning of its assemblages. The objective of this study was to compare the community and trophic structure of rocky bottom asteroids in two regions of the Gulf of California: Loreto and Ligüi (25.5° to 26.5°N). Individuals were censused in belt transects 25 × 2 m (N = 106, at depths from 3 to 12 m), abundance, species richness, diversity (H') and evenness (J') was estimated, as well as the number of seastars per trophic guild (carnivores, herbivores and detritivores), and of guilds present per transect. The results indicate that starfish assemblages in both zones were dominated by the species Phataria unifascialis, and that Loreto had significantly higher richness, abundance and diversity of asteroids than Ligüi, probably as a consequence of higher number of habitats and food resources. In relation to the trophic composition, in both areas herbivores predominated, followed by detritivores and finally by carnivores. Abundance in each trophic level was statistically higher in Loreto, and also there were more trophic groups per transect at that location.
The sponges, Halichondria bowerbanki Burton, Microciona prolifera (Ellis and Solander), Haliclona permollis (Bowerbank), and Craniella gravida (Hyatt), held the siphonostomous cyclopoid Cryptopontius gracilis Wilson, which was found to be histophagic and is redescribed. The first two species of these sponges also yielded the histophagic, siphonostomous cyclopoid, Asterocheres jeanyeatmanae n. sp. and the scavenger and algae-feeding harpacticoids, Tisbe furcata (Baird), Harpacticus gracilis Claus, Paralaophonte congenera (Sars), Dactylopodia tisboides (Claus), Amphiascopsis cinctus (Claus), Amphiascus parvus Sars, and Paralaophonte brevirostris (Claus). The last five of these species of harpacticoids are not previously reported for this area and the last three of these are partially redescribed.
Four copepod species of the genus Asterocheres (A. echinicola, A. latus, A. suberitis and A. complexus) are recorded for the first time as associated with Mediterranean sponges of the classes Calcarea and Demospongiae (orders Dictyoceratida, Dendroceratida, and Poecilosclerida). Individuals of A. suberitis are described for the first time as inhabiting sponges other than Suberites domuncula. The copepods seemed to use their trunk to suck the material (cuticles or excreted cells) produced at the sponge periphery (ectosome), which indicates that their feeding habits are similar to those observed in species of the same genus that feed on exfoliated tissues of echinoderms. In the laboratory, copepods fed on young sponges (rhagons) of the species Crambe crambe, Cacospongia mollior, and Dysidea avara without reducing the rhagon biomass. In contrast, rhagons of the species Haliclona sp., Hymedesmia spp., and Phorbas tenacior were consumed and their biomass reduced. This may be because the latter group does not produce external proteinaceous material. Copepod offspring were continuously released (∼6 nauplii every 48 h) and the larval stages were capable of limited swimming. We found significantly more copepods over the surface of the sponges than inside them. Copepod abundance was positively correlated with the sponge surface area while not with the sponge biomass. These results indicate that the copepods live preferentially over the sponge surface and that their abundance is surface-area dependent. The behavioral traits described here indicate that the interactions between asterocherid species and sponges are worthy of future study.
Living specimens of Asterocheres lilljeborgi (Boeck, 1859) (Copepoda: Cyclopoida) were observed on the sea star Henricia sanguinolenta from the Gullmarfjord, Sweden. Copepodid stages as well as males and females live ectoparasitically on the sea star. They maintain a motile way of life and do not posses special adaptations of body form and extremity structure to the echinoderm host. A. lilljeborgi digests the skin of H. sanguinolenta extra-intestinally and sucks up the food by means of the siphon-shaped mouth. The intestine has caeca, which become increasingly branched during the development from copepodid stages to male or to female. The number of eggs is low, 7 to 9 in each egg sack. During copulation, the ventral sides of the genital segments of both male and female approach each other closely, thus facilitating transfer of spermatophores. All larger H. sanguinolenta of the Gullmarfjord are infested by A. lilljeborgi. Comparison between Scottomyzon gibberum and A. lilljeborgi shows that the female of S. gibberum has become more modified in structure and behaviour than the A. lilljeborgi female. In order to characterize the degree of parasitic life of the two species (both Cyclopoida siphonostoma) the term "parasitic" (not "semiparasitic" or "associated") is suggested, because the nauplius larvae only are free living.
The Valvatacea is one the most ecologically important, taxonomically diverse, and widespread groups of post-Palaeozoic (i.e. modern) Asteroidea. Classification within the group has been historically problematic. We present a comprehensively sampled, three-gene (12S, 16S, early-stage histone H3) molecular phylogenetic analysis of the Valvatacea. We include five of the six families within the Paxillosida, the monotypic Notomyotida, and 13 of the 16 families of the living Valvatida. The Solasteridae is removed from the Velatida (Spinulosacea) and joins the Ganeriidae and the Leilasteridae as members of the clade containing the Asterinidae. The Poraniidae is supported as the sister group to the large cluster of Valvatacea. Asteropseids and poraniids are phylogenetically distant, contrary to morphological evidence. Several goniasterid-like ophidiasterids, such as Fromia and Neoferdina are supported as derived goniasterids rather than as Ophidiasteridae. The Benthopectinidae (Notomyotida) are supported as members of the Paxillosida as are two members of the Pseudarchasterinae that have traditionally been considered members of the Goniasteridae. Our data suggest that Antarctic valvataceans may be derived from sister taxa in adjacent regions.
© 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161, 769–788.
Siphonostomatoid Copepoda (Crustacea) associated with invertebrates from tropical waters
- I H Kim
- Kim, I. H