Alexandra Ostmann

First recording of kinorhynchs from Java, with the description of a new brackish water species from a mangrove-fringed lagoon

A new species of Echinoderes, E. applicitus sp. nov., is described from a brackish water lagoon on the south coast of Central Java, Indonesia. The species is recognized by its complete lack of spines on segments 1–10, lateroventral tubules on segments 5 and 8, laterodorsal tubules on segment 10, and a mid- to subdorsal tergal protrusion of segment 10 that extends beyond the posterior margin of segment 11. The general reduction of spine size and numbers, the absence of lateral terminal accessory spines in females and the enlarged sieve plate suggest a close relationship with E. rex, E. coulli, E. maxwelli and E. teretis. The adaptation to a brackish, estuarine habitat with highly fluctuating salinities is also shared between the three latter species and E. applicitus sp. nov. The examined populations of the new species had a relatively high infection rate (10–15%) of epibiontic growth from at least three different prokaryotic or protist organisms. An infection rate of this magnitude has not previously been reported for kinorhynchs, and it may have a relationship to the brackish habitat.

Traditional and confocal descriptions of a new genus and two new species of deep water Cerviniinae Sars, 1903 from the Southern Atlantic and the Norwegian Sea: with a discussion on the use of digital media in taxonomy (Copepoda, Harpacticoida, Aegisthidae)

Abstract Aegisthidae is one of the most abundant and diverse families of harpacticoid copepods living in deep-sea benthos, and the phylogenetic relationships within the family are in state of flux. Females of two new deep-water species of harpacticoid copepods belonging to the Hase gen. n. (Aegisthidae: Cerviniinae) are described. The first taxonomic description of marine copepod species based on the combined use of interference and confocal microscopy for the study of the habitus and dissected appendages is presented here. CLSM (Confocal Laser Scanning Microscopy) is a non-destructive method, comparable in quality to SEM (scanning electron microscopy) at the same magnifications. To observe and reconstruct in detail the habitus and dissected appendages, whole specimens and dissected parts were stained with Congo Red, mounted on slides with glycerine for CLSM and scanned under three visible-light lasers. Hase lagomorphicus gen. et sp. n. and Hase talpamorphicus gen. et sp. n. were collected from the sediments of the Southern Atlantic and the Norwegian Sea, from 2270 m and 5468 m depths, respectively. Hase gen. n. is included within Cerviniinae based on the caudal rami which are relatively divergent. Hase gen. n. is the sister taxon of Cerviniella based on the following synapomorphies: sturdy body, exopodites 1–3 of pereopods 1–3 heavily built, transformed into digging limbs, with strong outer and distal spines/setae, two-segmented endopod on the pereopods 2 and 3, and a reduced pereopod 5. Compared to Cerviniella, Hase gen. n. exhibits a more developed armature on the pereopod 1, which has outer and distal elements transformed into strong and long spines vs. stiff setae on Cerviniella.Hase gen. n. has one or two strong and long spines on the inner margin of the exopodite 3 of pereopod 4 and pereopod 5 is fused to the somite, ornamented with three distal setae. The telson of Hase gen. n. is subquadratic, and the furca is among the shortest yet described for Aegisthidae. The new species differ in a number of diagnostic characters, three of which are: a) the somite bearing pereopods 3 and 4 with latero-distal spiniform processes in H. talpamorphicus gen. et sp. n. but smooth in H. lagomorphicus gen. et sp. n., b) antenna is armed with three stout spines on the lateral inner margin of the exopod in H. talpamorphicus gen. et sp. n. and two proximal setae in H. lagomorphicus gen. et sp. n., and c) pereopod 4 exopodite 3 has two long and strong spines on the inner margin in H. lagomorphicus gen. et sp. n. and one spine in H. talpamorphicus gen. et sp. n. The high quality of CLSM images should foster discussion about the use of high quality digital images as type or as part of the type series in zoological studies, especially when studying rare and small macrofaunal and meiofaunal taxa.

Biogeographic distributions of Cytheropteron species (Ostracoda) in Icelandic waters (sub-polar North Atlantic)

The ostracod genus Cytheropteron (Ostracoda: Crustacea) has been widely used for paleoenvironmental, paleoceanographic, and paleobiogeographic studies. But species-level data remain limited, especially for deepwater species. Here, we show the depth and spatial distribution patterns of 33 species of the ostracod genus Cytheropteron found in recent surface sediments of Icelandic waters. Species-specific depth ranges may serve as a useful tool in ostracod-based paleoenvironmental reconstruction. Biogeographic distributions of Cytheropteron species indicate the shallow Greenland-Iceland-Faroe Ridge as the major barrier for the distribution of deep-sea organisms.