Sponges from Doumer Island, Antarctic Peninsula, with description of new species of Clathria (Axosuberites) Topsent, 1893 and Hymeniacidon Bowerbank, 1858, and a re-description of H. torquata Topsent, 1916

Zootaxa ◽  
2020 ◽  
Vol 4728 (1) ◽  
pp. 77-109
Author(s):  
JULIO C.C. FERNANDEZ ◽  
DIEGO BRAVO-GÓMEZ ◽  
CÉSAR A. CÁRDENAS ◽  
EDUARDO HAJDU

Antarctic sponges were mainly studied from trawling or dredging (shallow and deep water) during pioneering oceanographic expeditions carried out since the late 19th century. More recently, sponge collections by SCUBA diving have allowed the detection of species in more cryptic habitats such as rocky walls. In this study, we analyzed Antarctic sponges collected by SCUBA (in 2016 to 2018; shallower than 25 m) around Doumer Island (Palmer Archipelago, Western Antarctic Peninsula—WAP), where only five sponge species have been known. We gathered over 215 specimens, most part identified; 18 known species and one new species. Clathria (Axosuberites) retamalesi sp. nov., is set apart from its congeners on account of the combination of its habit, categories and dimensions of spicules. The East Antarctic material named as Hymeniacidon spec. (3397 m depth) from the Gauss scientific collection has been related to the shallow species H. torquata Topsent, 1916. We described H. torquata based in several specimens (n= 51) from Doumer Island (WAP), only ca. 41 km from Petermann Island (the type locality). Spicules of H. torquata are smaller than the ones present in the Hymeniacidon spec. material, which is here named Hymeniacidon hentscheli sp. nov., since it does not fit into any known cold water species of Hymeniacidon from Antarctica or the Southern Hemisphere, due to a combination of habit, oscula shape, and spicule dimensions. Only five sponge species were previously known from Doumer Island, also collected by SCUBA. Our findings suggest that the ongoing study of collections of sponges assembled at Doumer Island will still yield new taxonomic findings. 

2011 ◽  
Vol 25 (1) ◽  
pp. 60 ◽  
Author(s):  
Carla C. Stout ◽  
Nerida G. Wilson ◽  
Ángel Valdés

Dendronotus patricki, sp. nov. is a new species collected from a whalefall in the Monterey Canyon, California. This new species is characterised by having a small number of dorsal appendages compared with similarly sized species of Dendronotus Alder & Hancock, 1845. Anatomically, D. patricki, sp. nov. has a small prostate with just a few alveoli, a very small seminal receptacle situated near the distal end of the vagina, and a relatively short and small ampulla. The rachidian radular teeth of D. patricki, sp. nov. are unique among Dendronotus as they have a well differentiated, conical cusp with very small denticles on either side, but most denticles are located on the sides of the teeth, rather than on the sides of the cusp. Dendronotus patricki, sp. nov., is genetically distinct from other species of Dendronotus for which sequence data are available. A phylogenetic analysis of Dendronotus based on COI, 16S, and H3 sequence data reveals that D. patricki, sp. nov. forms a polytomy with Dendronotus orientalis (Baba, 1932) and a clade of the shallow temperate and cold water species. The tropical Indo-Pacific species D. regius Pola & Stout, 2008 is the sister group to all other Dendronotus species.


2018 ◽  
Author(s):  
M. González-Aravena ◽  
N.J. Kenny ◽  
M. Osorio ◽  
A. Font ◽  
A. Riesgo ◽  
...  

AbstractAlthough the cellular and molecular responses to exposure to relatively high temperatures (acute thermal stress or heat shock) have been studied previously, only sparse empirical evidence of how it affects cold-water species is available. As climate change becomes more pronounced in areas such as the Western Antarctic Peninsula, it has become crucial to understand the capacity of these species to respond to thermal stress.Here we use the Antarctic sponge Isodictya sp. to investigate how sessile organisms (particularly Porifera) can adjust to acute short-term heat stress, by exposing this species to 3 and 5 °C for 4 hours, corresponding to predicted temperatures under high-end 2080 IPCC-SRES scenarios. Assembling a de novo reference transcriptome (90,188 contigs, >93.7% metazoan BUSCO genes) we have begun to discern the molecular componentry employed by Isodictya to adjust to environmental insult.Our initial analyses suggest that TGF-β, ubiquitin and hedgehog cascades are involved, alongside other genes. However, the degree and type of response changed little from 3 to 5 °C, suggesting that even moderate rises in temperature could cause stress at the limits of this organism’s capacity. Given the importance of sponges to Antarctic ecosystems, our findings are vital for discerning the consequences of increases in Antarctic ocean temperature on these and other species.


2021 ◽  
Vol 41 (1) ◽  
Author(s):  
Jacqueline Bertlich ◽  
Nikolaus Gussone ◽  
Jasper Berndt ◽  
Heinrich F. Arlinghaus ◽  
Gerhard S. Dieckmann

AbstractThis study presents culture experiments of the cold water species Neogloboquadrina pachyderma (sinistral) and provides new insights into the incorporation of elements in foraminiferal calcite of common and newly established proxies for paleoenvironmental applications (shell Mg/Ca, Sr/Ca and Na/Ca). Specimens were collected from sea ice during the austral winter in the Antarctic Weddell Sea and subsequently cultured at different salinities and a constant temperature. Incorporation of the fluorescent dye calcein showed new chamber formation in the culture at salinities of 30, 31, and 69. Cultured foraminifers at salinities of 46 to 83 only revealed chamber wall thickening, indicated by the fluorescence of the whole shell. Signs of reproduction and the associated gametogenic calcite were not observed in any of the culture experiments. Trace element analyses were performed using an electron microprobe, which revealed increased shell Mg/Ca, Sr/Ca, and Na/Ca values at higher salinities, with Mg/Ca showing the lowest sensitivity to salinity changes. This study enhances the knowledge about unusually high element concentrations in foraminifera shells from high latitudes. Neogloboquadrina pachyderma appears to be able to calcify in the Antarctic sea ice within brine channels, which have low temperatures and exceptionally high salinities due to ongoing sea ice formation.


Author(s):  
Ryan C Grow ◽  
Kyle D Zimmer ◽  
Jennifer L Cruise ◽  
Simon K Emms ◽  
Loren M Miller ◽  
...  

Cisco (Coregonus artedi) are threatened by climate change and lake eutrophication, and their oxythermal habitat can be assessed with TDO3, the water temperature at which dissolved oxygen equals 3 mg L-1. We assessed the influence of TDO3 on cisco habitat use, genetic diversity, diets, and isotopic niche in 32 lakes ranging from oligotrophic to eutrophic. Results showed that as TDO3 increased cisco were captured higher in the water column, in a narrower band, with higher minimum temperatures and lower minimum dissolved oxygen. TDO3 was also negatively related to cisco allelic richness and expected heterozygosity, likely driven by summer kill events. Moreover, TDO3 influenced the isotopic niche of cisco, as fish captured deeper were more depleted in δ13C and more enriched in δ15N compared to epilimnetic baselines. Lastly, cisco in high TDO3 lakes consumed more Daphnia, had fewer empty stomachs, and achieved larger body size. Our work identifies specific characteristics of cisco populations that respond to climate change and eutrophication effects, and provides a framework for understanding responses of other cold-water species at the global scale.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andrey B. Imbs ◽  
Valeria P. Grigorchuk

AbstractNudibranch molluscs occur in marine ecosystems worldwide and prey on numerous invertebrate species. During feeding, dietary fatty acids (FAs) unusual for nudibranchs are transferred to their lipids. Normal biomembrane functions require stable composition of structural polar lipids (PL), but the pathways of dietary FA utilization to PL in nudibranchs still remain unknown. A combination of chromatography and tandem high-resolution mass spectrometry was used to determine total lipid, PL, FA, and PL molecular species composition of two cold-water species of Dendronotus, which then were compared with those of Tritonia tetraquetra. The use of FA trophic markers showed that Dendronotus sp. and T. tetraquetra prey on different soft corals, while D. robustus may consumes hydrocorals and bryozoans. Nudibranch FA profiles were strongly modified by dietary FAs but their PL profilers were similar. Dietary FAs are not included in ceramide aminoethylphosphonate and inositol glycerophospholipids, but directed to ethanolamine, choline, and serine glycerophospholipids and, in some cases, form isobaric molecular species with different FA chain lengths. For such isobaric species, nudibranchs reduce the length of alkyl groups when very-long-chain FAs are obtained with diet. This molecular mechanism may explain the adaptation of nudibranch membrane structure to dietary input of unusual FAs.


1994 ◽  
Vol 13 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Toshiaki Irizuki

Abstract. Seventy-eight ostracod species belonging to 38 genera are recognized from the late Miocene Fujikotogawa Formation (c. 7–8 Ma), 40 km NE of Akita City, northern Japan. Some 30–40% of the ostracod species belong to the cold water groups (circumpolar and cryophilic species) reported from Plio-Pleistocene formations yielding the Omma-Manganji Fauna, the name given by Otuka (1939) to the Pliocene Japanese cold water molluscan fauna. This study demonstrates that most ostracod species distinguished in deposits yielding the Omma-Manganji Fauna had already appeared in the late Miocene. At least 13 of the ostracod species have been reported from both the Arctic and northern Atlantic Oceans, implying migration from the Pacific to the northern Atlantic through the Arctic after the Bering Strait had been breached. The 13 circumpolar, nine cryophilic and four endemic cold water species are illustrated, with brief taxonomic notes.


2007 ◽  
Vol 16 (3) ◽  
pp. 31-42 ◽  
Author(s):  
Asbjørn Gildberg ◽  
Jetsada Wichaphon ◽  
Sittiwat Lertsiri ◽  
Apinya Assavanig ◽  
Nils K. Sørensen ◽  
...  

1998 ◽  
Vol 78 (4) ◽  
pp. 1093-1100 ◽  
Author(s):  
B.K. Ginn ◽  
A. Logan ◽  
M.L.H. Thomas ◽  
R.W.M. Van Soest

Sixteen sponge species were recorded from Little Letite Passage, an area of highvelocity tidal currents located in the Bay of Fundy near Deer Island, New Brunswick, Canada. Of these 16 species, four species (Myxilla fimbriata, Hymeniacidon heliophila, Hemigellius sp. aff. flagellifer, and Crella rosea) have not previously been recorded from the Bay of Fundy. One new species, Hymedesmia canadensis, is described, based on the presence of a second peculiar chelate microsclere added to the spicule armament.


2020 ◽  
Author(s):  
Carmen García-Comas ◽  
Chih-hao Hsieh ◽  
Sanae Chiba ◽  
Hiroya Sugisaki ◽  
Taketo Hashioka ◽  
...  

ABSTRACTClassic niche theory assumes that species-level functional traits affect species relative fitness and thus community structuring, but empirical tests of this assumption are scarce. Moreover, recent evidence shows increasing functional over-redundancy towards the tropics, suggesting that the extent to which functional traits confer species’ fitness and thus impact community structuring differs across latitudes. Here, we develop a new method: comparing the frequencies of trait categories in the species-rank abundance distributions of local communities versus their frequencies in the regional average species pool. We contrasted subarctic versus subtropical copepod communities for six important traits. In subarctic communities, medium-sized and cold-water species are selected to dominate, thus traits affect relative fitness as predicted by classic niche theory. In subtropical communities, most species are small and warm-water, but these categories are not selected to dominate, suggesting that greater diversity towards the tropics results from lesser trait-based fitness differences allowing more species to coexist.


2021 ◽  
Vol 51 (2) ◽  
pp. 153-158
Author(s):  
Tak-Kei Chou ◽  
Chi-Ngai Tang

The goldeye rockfish, Sebastes thompsoni (Jordan et Hubbs, 1925), is known as a typical cold-water species, occurring from southern Hokkaido to Kagoshima. In the presently reported study, a specimen was collected from the local fishery catch off Keelung, northern Taiwan, which represents the first specimen-based record of the genus in Taiwan. Moreover, the new record of Sebastes thompsoni in Taiwan represented the southernmost distribution of the cold-water genus Sebastes in the Northern Hemisphere.


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