Three new species of Paralomis (Crustacea, Decapoda, Anomura, Lithodidae) from the Pacific and Antarctic Oceans

Three new species of the lithodid genus Paralomis from the Sulawesi (Celebes) Islands, P. ochthodes sp.n., Chilean coast, P. tuberipes sp.n., and Antarctic Ocean, P. birsteini sp.n., are described and illustrated. The first two species have features that set them well apart from other species of the genus. Characters are also given to distinguish P. birsteini from the closely allied P. spectabilis Hansen (North Atlantic).     

Temperature-driven biogeography of the deep-sea family Lithodidae (Crustacea: Decapoda: Anomura) in the Southern Ocean

Species’ distributions are dynamic and are linked to the changing physical environment. Temperature is considered to be a major factor influencing biogeography, especially in ectotherms such as the family Lithodidae. Lithodids are rare amongst decapods in their ability to inhabit the higher latitudes of the Southern Ocean; however, they are usually found in locations where water temperature is above 0.5°C. This study, for the first time, provides a baseline indication of the limits of the lithodid distribution around Antarctica, which will be instrumental in any future work on range extensions in this group. The distribution of lithodids is likely to change as temperatures along the West Antarctic Peninsula continue to rise, and range extensions by durophagous predators, such as the lithodids, are regarded as a potential threat to the unique structure of Antarctic continental-shelf ecosystems.     

First record of anomuran and brachyuran larvae (Crustacea: Decapoda) from Antarctic waters

Two decapod crustacean larval morphotypes belonging to the Anomura and Brachyura were found for the first time in Antarctic waters. Nine specimens were obtained from qualitative plankton hauls in Maxwell Bay (Bransfield Strait) (62°14'33S; 58°43'81W) off King George Island, Antarctic Peninsula. The anomuran morphotype belonged to the Hippidae, and apparently to the genus Emerita, whereas the brachyuran representative was assigned to the genus Pinnotheres (Pinnotheridae). At present, species determination is not possible due to lack of knowledge of larval morphology in both families. Adult forms of these reptant decapods are not known from Antarctic waters; the occurrence of the present larval forms is considered as a possible intrusion of Subantarctic water masses into the Antarctic environment. This hypothesis is supported by the additional presence of the copepod genus Acartia in the same sample material, which is exclusively known from Subantarctic waters.     

Leptostraca,Mysidacea, Isopoda,and Decapoda (Anomura) (Crustacea,Malacostraca) of the Chukchi Sea and Adjacent Waters: Biogeography and Fauna Formation

Data on the distribution of 72 species of Leptostraca, Decapoda: Reptantia: Anomura, Mysidacea, and Isopoda in the northern Bering Sea, the Chukchi and East Siberian seas, and the adjacent areas of the continental slope in the Arctic basin at depths less than 500 m were used for biogeographic analysis. According to distribution, these species can be united into 15 biogeographic groups. The hydrological regime, primarily, the distribution of waters of different origin in the investigated regions, governs the distribution of different biogeographic groups of crustaceans. Pacific boreal and subtropic-boreal species mostly inhabit the southern part of the Chukchi Sea, coastal waters off Alaska to Point Barrow, and the central region of this sea to the Herald Bank. For these taxa, the boundary between the Pacific and Arctic faunas is in the Chukchi Sea crossing from Cape Serdtse Kamen and Point Barrow to the area west of the Herald Bank. Possible pathways and the major stages of formation of the fauna of the investigated crustaceans for the last 18000 years are discussed.     

Cumaceans (Crustacea) from the Bellingshausen Sea and off the western Antarctic Peninsula: a deep-water link with fauna of the surrounding oceans

During the austral summers of 2003 and 2006, two cruise were carried out in the Bellingshausen Sea and west off Antarctic Peninsula on board of RV Hespérides. Samples were collected at 26 stations with a multinet Macer-GIROQ sled. A total of 557 cumaceans belonging to 36 species of five families were collected. Nannastacidae was the most abundant and speciose family. Hemilamprops pellucidus and Cyclaspis gigas were the most frequently collected species (38.5% of sampling stations). Cumella asutralis reached the highest density (514.7 individuals/1,000 m² at stn 7). Maximum species richness (S = 15) and diversity (H′ = 3.53) was observed at one of the deepest station. Positive correlations were found between the cumacean distribution and the organic content and percentage of coarse sand of the sediments. Predominance of Nannastacidae in front of other cumaceans could be explained by their type of feeding (i.e. predators or scavengers), which may be more successful in the deep seafloor of an oligotrophic sea such as studied herein. The presence in the deepest sampling sites of species shared with faunas of surrounding oceans suggests a link between these faunas and those of deep Antarctic waters.     

A new distinctive species of pagurid hermit crab (Crustacea: Decapoda: Anomura) from Japan

A new species of pagurid hermit crab, Pagurus decimbranchiae, is described and illustrated based on 20 specimens collected from shallow waters of the Pacific coast of Japan ranging from Boso Peninsula to Tanegashima Island. It is quite distinctive in having the rudimentary arthrobranch on the third maxilliped represented by a single bud, however close morphological similarity is found between the new species and P. moluccensis Haig and Ball. Comparisons are also made among other species, including P. boriaustraliensis Morgan, P. sp. cf. boriaustraliensis sensu Rahayu and Komai (2000) and the members of the P. anachoretus group. The present generic assignment of the new species should be considered provisional, as more extensive study is needed to investigate phylogenetic relationships of the new species and the other species of Pagurus.     

New species of Pogonophryne (Pisces, Artedidraconidae) from the Bellingshausen Sea, Antarctica

A new species of notothenioid fish, Pogonophryne bellingshausenensis n. sp., is described from the Bellingshausen Sea, Antarctica. The new species belongs to the dorsally-spotted “mentella” group of the genus and is characterized by having a short (about 13% SL) mental barbel with a short (about 16% of barbel length), narrow (barely wider than the stalk), and relatively inconspicuous terminal expansion composed of short, irregular, fingerlike processes. Compared to most other dorsally-spotted species of Pogonophryne (“barsukovi”, “marmorata”, and “mentella” groups), P. bellingshausenensis has a relatively wide (about 7% SL) interorbital region. An unspotted patch on the median dorsal surface of the head, posterior to the posttemporal ridges and anterior to the first dorsal fin, has not been observed previously in any dorsally-spotted species. The holotype was collected at 1,947 m, one of the deepest records for any species of Pogonophryne. A revised key to the ten species of the “mentella” group of Pogonophryne is also provided.     

Leptostraca,Mysidacea, Isopoda,and Decapoda (Anomura) (Crustacea,Malacostraca) of the Chukchi Sea and Adjacent Waters: Hydrological Regime and Species Composition

The hydrological regime of the region is briefly outlined. The distribution of waters of Arctic and Pacific origin is discussed. Based on the original and literature data, it has been found that 73 species of the investigated orders occur in the northern part of the Bering Sea, in the Chukchi and East Siberian seas, and in the adjoining areas of the continental slope of the Arctic basin at depths down to 500 m. These are 1 leptostracan species, 11 anomurans, 22 mysids, and 39 free-living isopods. The distribution of these species by depth and in relation to the thermal and salinity characteristics of waters is analyzed.     

New hyperbenthic species of Misophriopsis and Misophriella, first record of misophrioid copepods (Crustacea) from Antarctic waters

  Misophrioid copepods are reported for the first time from Antarctic waters. A species of each of the genera Misophriopsis and Misophriella is described from hyperbenthic layers of the continental shelf of the eastern Weddell Sea. The genus Misophria is also reported from these waters. Misophriopsis australis sp. nov. is the fifth representative of this widely distributed genus, previously reported from the North Atlantic, the China Sea, and both NW and NE quadrants of the Pacific Ocean. Misophriella schminkei sp. nov. is the second representative of the genus, known to date only from a single female caught in North Atlantic bathyal depths. Traces of subdivisions on antennary exopodal segments of the latter species suggest that the first segment may be a triple segment, while the second and terminal segments may be double segments. In addition, the mandibular exopod of this taxon indicates that a six-segmented ramus with setal formula 0, 1, 1, 1, 1, 2 may represent the ground pattern in Copepoda. The presence of parts of a cyclopinid copepod in the gut of M. schminkei sp. nov. indicates that this species may be carnivorous. Received: 12 November 1998 / Received in revised form: 26 July 1999 / Accepted: 27 July 1999     

New species and new records of pinnotherid crabs (Crustacea: Decapoda: Brachyura) from the Yellow Sea

Five species belonging to two genera of pinnotherid crabs are reported from the Yellow Sea. Two are new to science, namely: Sakaina glabra sp. nov. and Sakaina granulata sp. nov.; while three species are recorded for the first time from China: Pinnaxodes majorOrtmann, 1894, Pinnaxodes mutuensisSakai, 1939, and Sakaina japonicaSerène, 1964. Sakaina glabra can be easily distinguished from congeners by lacking a thick rim of pubescence along the anterolateral margin of the carapace. Sakaina granulata closely resembles S. asiatica (Sakai, 1933), but differs mainly in having a row of granule-like denticles along the anterolateral margin of its carapace.     

A new species and new records of lithodid crabs (Crustacea: Decapoda: Lithodidae) from the Crozet and Kerguelen Islands area (Subantarctica)

Four species of lithodid crabs from waters (240–2,005 m) in the Crozet and Kerguelen Islands area were studied. One new species, Neolithodes duhameli, is described. Three other species, N. capensis Stebbing, Paralomis anamerae Macpherson and P. birsteini Macpherson are reported for the first time from these localities. The new species, N. duhameli (620–1,500 m), is the fourth representative of the genus in Subantarctic waters and belongs to the group of species possessing a carapace, chelipeds and walking legs covered with numerous spinules or spiniform granules in addition to spines. However, the new species is distinguishable from others in the genus by the long, strong spines on the carapace and pereiopods. The finding of two species of Paralomis clearly extends their geographic ranges in the Southern Ocean: P. anamerae was previously known only in waters of the Falkland Islands and the circumpolar distribution of P. birsteini is supported. The observation of N. capensis also extends its previously described range from South Africa, in the Cape region, to Subantarctic waters. As a result of this study, 14 species of the family Lithodidae are now known from Antarctic and Subantarctic waters; and most can be considered endemic to these waters.     

A description of larval and early juvenile development in Paralomis spinosissima (Decapoda: Anomura: Paguroidea: Lithodidae) from South Georgia waters (Southern Ocean)

The early ontogenetic stages of Paralomis spinosissima Birstein and Vinogradow, 1972, are described in detail and illustrated, with notes on morphological variability observed. Larval and early juvenile development was described to the crab I instar reared under controlled conditions of temperature and food supply. The abbreviated larval development invariably passed through two zoeal stages and the benthic megalopa stage. The larval development was completed without food supply, and food Artemia nauplii were first given after moult to the crab-I stage. Simplification and retarded development of the mouthparts are discussed as a function of lecithotrophy of these larvae and based on morphology no facultative feeding mode is suggested. Lecithotrophy in the Southern Ocean Lithodidae is discussed to be an adaptation allowing independence from seasonal food availability at high latitudes.     

Larval and early juvenile development of Lithodes santolla (Molina, 1782) (Decapoda: Anomura: Lithodidae) reared at different temperatures in the laboratory

The southern king crab, Lithodes santolla Molina, is distributed in cold-temperate and subantarctic waters ranging from the southeastern Pacific island of Chiloé (Chile) and the deep Atlantic waters off Uruguay, south to the Beagle Channel (Tierra del Fuego, Argentina/Chile). Recent investigations have shown that its complete larval development from hatching to metamorphosis, comprising three zoeal stages and a megalopa, is fully lecithotrophic, i.e. independent of food. In the present study, larvae were individually reared in the laboratory at seven constant temperatures ranging from 1 to 18 °C, and rates of survival and development through successive larval and early juvenile stages were monitored throughout a period of 1 year. The highest temperature (18 °C) caused complete mortality within 1 week; only a single individual moulted under this condition, 2 days after hatching, to the second zoeal stage, while all other larvae died later in the zoea I stage. At the coldest condition (1 °C), 71% of the larvae reached the zoea III stage, but none of these moulted successfully to a megalopa. A temperature of 3 °C allowed for some survival to the megalopa stage (17-33% in larvae obtained from two different females), but only a single individual passed successfully, 129 days after hatching, through metamorphosis to the first juvenile crab instar. At all other experimental conditions (6, 9, 12 and 15 °C), survival through metamorphosis varied among temperatures and two hatches from 29% to 90% without showing a consistent trend. The time of nonfeeding development from hatching to metamorphosis lasted, on average, from 19 days at 15 °C to 65 days at 6 °C. The relationship between the time of development through individual larval or juvenile stages (D) and temperature (T) was described as a power function (D=aT^b, or log[D]=log[a]blog[T]). The same model was also used to describe the temperature dependence of cumulative periods of development from hatching to later larval or juvenile stages. One year after hatching, the 7th (6 °C) to 9th (15 °C) crab instar was reached. Under natural temperature conditions in the region of origin of our material (Beagle Channel, Argentina), L. santolla should reach metamorphosis in October-December, i.e. ca. 2 months after hatching (taking place in winter and early spring). Within 1 year from hatching, the crabs should grow approximately to juvenile instars VII-VIII. Our results indicate that the early life-history stages of L. santolla tolerate moderate cold stress as well as planktonic food-limitation in winter, implying that this species is well adapted to subantarctic environments with low temperatures and a short seasonal plankton production.     

High genetic differentiation of Aegla longirostri (Crustacea, Decapoda, Anomura) populations in southern Brazil revealed by multi-loci microsatellite analysis

Species with a broad distribution rarely have the same genetic make-up throughout their entire range. In some cases, they may constitute a cryptic complex consisting of a few species, each with a narrow distribution, instead of a single-, widely distributed species. These differences can have profound impacts for biodiversity conservation planning. The genetic differentiation of four populations of Aegla longirostri, a freshwater crab found in two geographically isolated basins in Rio Grande do Sul State, Brazil, was investigated by analyzing pentanucleotide multi-loci microsatellites in a heteroduplex assay. Although no morphological differences were evident, we found significant genetic differentiation among the four populations, based on F(ST) values and clustering analysis. This high level of differentiation may be indicative of cryptic species in these populations. If this hypothesis is correct, then the species occurring in the Ibicuí-Mirim River, at the southern limit of the Atlantic Rain Forest, would be under threat, considering its very restricted distribution.     

Microsatellite loci from the pink shrimp Farfantenaeus notialis (Crustacea,Decapoda)

Farfantepenaeus notialis is an important resource for fisheries in Cuba. For this reason and for a sustainable exploitation it is important to study their population structure and genetic variability. We report and characterize microsatellites as genetic markers from this species. Fifteen microsatellite polymerase chain reaction (PCR) primers were designed and tested in some individuals from different populations. Seven pair of primers showed reliable amplification products and five were polymorphic. The allele number ranged from 4 to 33, and the observed and expected heterozygosities were relatively high with values between 0.63 and 0.74 and 0.56 and 0.81, respectively. Departures from Hardy–Weinberg equilibrium were observed for all loci.     

First record of a lecithotrophic nauplius in Harpacticoida (Crustacea,Copepoda) collected from the Weddell Sea (Antarctica)

Summary During an investigation of the meiofauna communities of the eastern Weddell Sea (Antarctica) the first naupliar stage of a new species of Pseudotachidius T. Scott, 1897 (Thalestridae) was held in culture on board R V Polarstern. These nauplii are extraordinary for a harpacticoid copepod in being globular in shape and densely filled with yolk. They lack mouth, gut tube, anus and the masticatory parts of the appendages, all of which indicate that they do not feed. It is not unlikely that later stages are also able to subsist safely on the large yolk reserves.     

The ovarian maturation cycle of the Norway lobster Nephrops norvegicus (Linnaeus, 1758) (Crustacea,Decapoda) from the western Mediterranean Sea

Summary

The Norway lobster Nephrops norvegicus lives in the continental margins of the western Mediterranean Sea at depths between 100 and 600 m. It constitutes an important fisheries resource and presents a seasonal reproductive pattern. Female Norway lobsters were obtained each month from a vessel fishing off Barcelona. One hundred females caught in June 2002 were kept in the laboratory. After spawning, ovarian samples were taken every 30 days with the objective of monitoring the first steps in ovarian maturation. The gonado-somatic index (GSI) remained low over the 6 months during which the females carried their eggs, plus for a further 2–3 months. However, this study suggests that ovarian maturation is a continuous process with two different phases, taking at least 6–8 months during which the female carries its eggs. There is an increase in oocyte numbers; the germinal zone produces oogonia; and the oocytes that develop migrate to the periphery, pushing the post-ovulatory follicles to the wall of the ovary and reinforcing it for subsequent spawning. Besides this increase in the number of oocytes, vitellogenesis begins 2–3 months after the eggs hatch. Oocytes then grow and the ovaries gain weight and change from a cream color to a blackish-green. When the GSI reached 10, spawning occurred and, from then on, the ovary is mainly composed of post-ovulatory follicles.