Rongcheng Lin

Abundance and distribution of meiofauna in the Chukchi Sea

The metazoan meiofauna in the Chukchi Sea were collected from seven shallow water stations (depths ranging 46 to 52 m) and five deep sea stations (depths ranging between 393 and 2 300 m) during the 4th Chinese National Arctic Research Expedition in 2010. The results showed that abundance of meiofauna was higher in shallow water sediments (average of 2 445 ind./(10 cm2)) than in deep sea sediments (407.06 ind./(10 cm2)). A UNIANOVA test for difference between the two different regions was highly significant (F=101.15, p<0.01). Nematodes were numerically dominant, representing (96.6±4.6)% of the total meiofaunal abundance at the shallow water stations and (98.90±1.42)% at deep sea stations. The number of higher taxonomic groups and abundance of meiofauna were higher at Stas CC1, CC4, and R06 near the Bering Strait and the continent, than at the rest of the shallow water and deep sea stations. The primary factors causing the differences were concentrations of nutrients P and Si of bottom seawater (R=0.831, p<0.003), followed by depth (R=−0.655, p<0.05) and sand fractions of sediments (R=0.632, p <0.05). The numbers of meiofauna on the 65 μm and 32 μm sieves were significantly higher than those on the rest of the screens. Differences in numbers of meiofauna retained on screens with different mesh openings were highly significant among all sampling stations (F=31.60, p<0.01). The highest numbers of individuals on screens with 32 μm mesh openings were found at deep sea stations. The number of meiofauna in the top 0–1, 1–2, and 2–4 cm segments constituted 84.4% of the total and was significantly higher than those in the bottom 4–6 and 6–10 cm segments (F=15, p<0.01).

A new yeti crab phylogeny: Vent origins with indications of regional extinction in the East Pacific

The recent discovery of two new species of kiwaid squat lobsters on hydrothermal vents in the Pacific Ocean and in the Pacific sector of the Southern Ocean has prompted a re-analysis of Kiwaid biogeographical history. Using a larger alignment with more fossil calibrated nodes than previously, we consider the precise relationship between Kiwaidae, Chirostylidae and Eumunididae within Chirostyloidea (Decapoda: Anomura) to be still unresolved at present. Additionally, the placement of both new species within a new “Bristly” clade along with the seep-associated Kiwa puravida is most parsimoniously interpreted as supporting a vent origin for the family, rather than a seep-to-vent progression. Fossil-calibrated divergence analysis indicates an origin for the clade around the Eocene-Oligocene boundary in the eastern Pacific ~33–38 Ma, coincident with a lowering of bottom temperatures and increased ventilation in the Pacific deep sea. Likewise, the mid-Miocene (~10–16 Ma) rapid radiation of the new Bristly clade also coincides with a similar cooling event in the tropical East Pacific. The distribution, diversity, tree topology and divergence timing of Kiwaidae in the East Pacific is most consistent with a pattern of extinctions, recolonisations and radiations along fast-spreading ridges in this region and may have been punctuated by large-scale fluctuations in deep-water ventilation and temperature during the Cenozoic; further affecting the viability of Kiwaidae populations along portions of mid-ocean ridge.

Amphipods fail to suppress the accumulation of Ulva lactuca biomass in eutrophic Yundang Lagoon

The Gross growth efficiency (GGE) is defined as the amount of consumer carbon produced relative to the amount of prey ingested in a given time interval. In population ecology, it can be considered as an index for the ability of a consumer to convert the biomass of food into its population production. In this study, it was firstly applied to estimate the role of amphipods grazing in the biomass dynamics of macroalgae (Ulva lactuca) in Yundang Lagoon (a subtropical eutrophic coastal lagoon, Xiamen City, China). It was found that amphipods were the dominant group (82.2%–98.7%) in the benthic assemblage, in which five amphipod species (Corophium uenoi, Ampithoe valida, Grandidierella japonica, Grammaropsis laevipalmata and Caprella panantis) were observed in the lagoon. However, only A. valida significantly consumed U. lactuca among these amphipod species. A series of experiments were conducted to estimate the consumption of U. lactuca by A. valida. It was suggested that the monthly secondary production (P) of A. valida using size frequency method ranged from 2.39 to 13.68 g/m2. GGE of A. valida exponentially reduced with body size and was closely associated with water temperature. Therefore, GGE equation for different months using the temperature recorded during the field investigation was fitted. The monthly consumption of U. lactuca was figured out to be 86.7–1 549.0 g/m2 by the sum of consumption (P/GGE) by A. valida at different size, accounting for 2.0%–37.5% of U. lactuca production. It indicates that the grazing effect of A. valida did play a role in reducing the accumulation of U. lactuca biomass when A. valida was abundant, but it finally fails to limit the U. lactuca growth in Yundang Lagoon. Low abundance of A. valida and high nutrient loading may be two major reasons for the outbreak of U. lactuca bloom in the lagoon.

A new species of deep-sea squat lobster of the genus Munida Leach, 1820 (Crustacea: Decapoda: Anomura: Munididae) from a hydrothermal field in the southwestern Indian Ocean

A new species of the genus Munida Leach, 1820, is described and illustrated based on a single specimen from the deep-sea hydrothermal area in the southwestern Indian Ocean. Munida manqingae sp. nov. closely resembles M. tiresias Macpherson 1994, but differs in the morphology of the carapace, basal segment of the antennular peduncles, first segment of the antennal peduncle.

The complete mitogenome of Pentacheles validus (Decapoda: Polychelidae)

Abstract In this study, the complete mitogenome sequence of Pentacheles validus has been decoded for the first time. The overall base composition is 33.4% for A, 25.0% for C, 10.8% for G, and 30.9% for T and has low GC content of 35.8%. The assembled mitogenome, 16,079 bp in length, has unique 13 protein-coding genes (PCGs), 22 transfer RNAs and 2 ribosomal RNAs. The mitogenome shares 80% identity to Polycheles typhlops. The complete mitogenome of P. validus provides essential DNA molecular data for further phylogenetic and evolutionary analysis for Polychelidae and deep-sea faunas.

The complete mitogenome of Acropora nana (Cnidarian: Acroporidae)

Abstract Acropora nana belongs to Cnidaria phylum, Anthozoa class, and staghorn coral groups. Like other corals, Acropora could be an indicator for environmental changes and with great conservational values. In this study, the complete mitogenome sequence of A. nana (Cnidarian: Acroporidae), has been decoded for the first time by low coverage whole genome sequencing method. The overall base composition of A. nana mitogenome is 25.0% for A, 13.8% for C, 24.4% for G, and 36.9% for T, and has low GC content of 38.2%. The assembled mitogenome, consisting of 18,480 bp, has unique 13 protein-coding genes (PCGs), three transfer RNAs, and two ribosomal RNAs genes. The A. nana has one big intron insert in ND5 gene. The complete mitogenome of A. nana provides essential and important DNA molecular data for further phylogenetic and evolutionary analysis for stony corals.

Two new free-living nematode species of Setosabatieria (Comesomatidea) from the East China Sea and the Chukchi Sea

Two new free-living marine nematode species of the genus Setosabatieria from the sandy intertidal zone of Xiamen, in the East China Sea and a shallow water area in the Chukchi Sea, Arctic Ocean are described and illustrated. Setosabatieria longiapophysis sp. nov. is characterized by four longitudinal files with 7–9 cervical setae per file, 15–16 minute papillate precloacal supplements and relatively long straight apophyses of gubernaculum. Setosabatieria major sp. nov. is identified by its relatively large body of 2701–3144 µm, the number (10–11) of cervical setae per file, 26–28 minute papillate precloacal supplements and spicules with a central septum at both the proximal and distal end. A pictorial identification key to all known species of Setosabatieria is provided. http://zoobank.org/urn:lsid:zoobank.org:pub:B8A2BEC9-5CD4-4AA9-9CA8-D1AE1FDE4887

A new species of Austrodecus Hodgson, 1907 (Arthropoda, Pycnogonida, Austrodecidae) from the Southwest Indian Ridge

Abstract A new species of pycnogonid collected by the Chinese research vessel R/V Dayangyihao during cruises to the Southwest Indian Ridge in 2008 and 2009 is recorded. The new species, Austrodecus bamberi, is placed into the tristanense-section by the characters of 4-articled ovigers and present auxiliary claws and is distinguished from other species in this section by the number and length of tubercles on the first coxae.