Brandt A.,Biocentre Grindel and Zoological Museum
Zootaxa | Year: 2013
During the Victoria-Land Transect project two specimens of a new species, Fissarcturus walteri sp. nov., were found in the Ross Sea along the Victoria Land Coast, Antarctica, during the 19th Italica expedition in February 2004. This is the second species of Fissarcturus from the Ross Sea after F. rossi Brandt, 2007. F. walteri sp. nov. is most similar to Fissar-cturus granulosus (Nordenstam, 1933) from South Georgia but can be distinguished by the blunt short, anteriorly directed supraocular spines and elevations and some other characters as described herewith. Copyright © 2013 Magnolia Press.
Koch M.,University of Bonn |
Schulz J.,Biocentre Grindel and Zoological Museum |
Edgecombe G.D.,Natural History Museum in London
ZooKeys | Year: 2015
Mandibular mechanisms in Geophilomorpha are revised based on three-dimensional reconstructions of the mandibulo-tentorial complex and its muscular equipment in Dicellophilus carniolensis (Placodesmata) and Hydroschendyla submarina (Adesmata). Tentorial structure compares closely in the two species and homologies can be proposed for the 14/17 muscles that attach to the tentorium. Both species retain homologues of muscles that in other Pleurostigmophora are traditionally thought to cause swinging movements of the tentorium that complement the mobility of the mandibles. Although the original set of tentorial muscles is simplified in Geophilomorpha, the arrangement of the preserved homologues conforms to a system of six degrees of freedom of movement, as in non-geophilomorph Pleurostigmophora. A simplification of the mandibular muscles is confirmed for Geophilomorpha, but our results reject absence of muscles that in other Pleurostigmophora primarily support see-saw movements of the mandibles. In the construction of the tentorium, paralabial sclerites seem to be involved in neither Placodesmata nor Adesmata, and we propose their loss in Geophilomorpha as a whole. Current insights on the tentorial skeleton and its musculature permit two alternative conclusions on their transformation in Geophilomorpha: either tentorial mobility is primarily maintained in both Placodesmata and Adesmata (contrary to Manton’s arguments for immobility), or the traditional assumption of the tentorium as being mobile is a misinterpretation for Pleurostigmophora as a whole. © Markus Koch et al.
Wurzberg L.,Biocentre Grindel and Zoological Museum |
Zinkann A.-C.,Biocentre Grindel and Zoological Museum |
Brandt A.,Biocentre Grindel and Zoological Museum |
Janussen D.,Senckenberg Institute |
And 2 more authors.
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2014
The zone surrounding the Antarctic Polar Front is a region characterized by elevated seasonal primary production. Studies on the implications for the fauna inhabiting the underlying deep-sea floor, however, are rare. The present study focuses on the abundance of megafaunal organisms caught by means of an Agassiz Trawl during the SYSTem COupling in the Southern Ocean II (SYSTCO II) expedition (RV Polarstern cruise ANT XXVIII/3). Biomass estimates in terms of volume as well as species richness of echinoderms were additionally taken into account. Abyssal stations (ca. 4000m depth) located in three different regions along the Antarctic Polar Front characterized by different primary production regimes and oceanographic features were sampled. One shallower station (337m depth) was used as reference station. Highest megafaunal abundances were found at the shallow station (147 individuals per 1000m2). Megafaunal abundances were low to moderate at the abyssal stations (7.2-23.5 individuals per 1000m2) with the exception of the region northwest of South Georgia, where distinctly higher abundances were found (up to 119.7 individuals per 1000m2). The same pattern was observed for biomass estimates. At the other regions, magnitude of megafaunal abundances and echinoderm biomasses were found not to be linked to the surface levels of primary production. This indicates that strong pelagic-benthic coupling likely occurs only downstream of South Georgia. Echinoderm species richness does not appear to be directly related to the environmental conditions as it does not differ statistically between the considered areas. © 2014 Elsevier Ltd.