Combining morphological and mitochondrial DNA data to describe a new species of Austroniscus Vanhöffen, 1914 (Isopoda, Janiroidea, Nannoniscidae) linking abyssal and hadal depths of the Puerto Rico Trench.

Hadal trenches are perceived as a unique deep-sea ecosystem with fundamentally different communities compared to the nearby abyss. So far, however, scarce information exists about how populations are genetically linked within a trench and about mechanisms for species divergence. The present study presents the morphological and molecular-genetic characterization and description of a new nannoniscid species within the genus Austroniscus Vanhöffen, 1914 obtained from abyssal and hadal depths of the Puerto Rico Trench, NW Atlantic. Samples were collected as part of the Vema-TRANSIT expedition onboard RV Sonne in January 2015. Because of the large depth differences between sampling locations (4,552-8,338 m), we expected to find different species within the genus inhabiting abyssal and hadal sites. Initial morphological examination using traditional light microscopy and Confocal Laser Scanning Microscopy was paired with subsequent molecular analysis based on mtDNA (COI and 16S). Contrary to our assumptions, combined morphological and molecular species delimitation analyses (sGMYC, mPTP, ABGD) revealed the presence of only one species spanning the abyssal and hadal seafloor of the Puerto Rico Trench. In addition, comparison with type material could show that this species belongs to a new species, Austroniscus brandtae n. sp., which is described herein. Incongruence between some species delimitation methods suggesting the presence of multiple species is interpreted as strong genetic population structuring within the trench, which is also supported by the analysis of the haplotype networks. The geographic and bathymetric distribution of Austroniscus species is discussed. The species described herein represents the first in the genus Austroniscus from the Atlantic Ocean and the deepest record of the genus to date, and hence significantly expanding previously known limits of its geographic and bathymetric range.

Megafauna of the German exploration licence area for seafloor massive sulphides along the Central and South East Indian Ridge (Indian Ocean).

BACKGROUND: The growing interest in mineral resources of the deep sea, such as seafloor massive sulphide deposits, has led to an increasing number of exploration licences issued by the International Seabed Authority. In the Indian Ocean, four licence areas exist, resulting in an increasing number of new hydrothermal vent fields and the discovery of new species. Most studies focus on active venting areas including their ecology, but the non-vent megafauna of the Central Indian Ridge and South East Indian Ridge remains poorly known.In the framework of the Indian Ocean Exploration project in the German license area for seafloor massive sulphides, baseline imagery and sampling surveys were conducted yearly during research expeditions from 2013 to 2018, using video sledges and Remotely Operated Vehicles. NEW INFORMATION: This is the first report of an imagery collection of megafauna from the southern Central Indian- and South East Indian Ridge, reporting the taxonomic richness and their distribution. A total of 218 taxa were recorded and identified, based on imagery, with additional morphological and molecular confirmed identifications of 20 taxa from 89 sampled specimens. The compiled fauna catalogue is a synthesis of megafauna occurrences aiming at a consistent morphological identification of taxa and showing their regional distribution. The imagery data were collected during multiple research cruises in different exploration clusters of the German licence area, located 500 km north of the Rodriguez Triple Junction along the Central Indian Ridge and 500 km southeast of it along the Southeast Indian Ridge.

Revision of the genus Laophontodes T. Scott (Copepoda, Harpacticoida, Ancorabolidae), including the description of a new species and a key to species.

The description of Laophontodes volkerlehmanskii sp. nov. (Copepoda, Harpacticoida, Laophontodinae Lang) from the deep sea of the Kairei Field, western Indian Ocean, prompted the examination of the phylogenetic status of Laophontodes T. Scott and the relationships within the genus. The allocation of L. volkerlehmanskii sp. nov. to Laophontodes based on diagnostic characters was relatively straightforward, yet phylogenetic analysis of the genus considering 39 morphological characters detected not a single autapomorphy. This indicates that Laophontodes, which seems to form a monophylum with Ancorabolina George and Bicorniphontodes George, Glatzel & Schröder, actually represents the stem-lineage, retaining the characters of the common ancestor without having developed unique derived morphological characters. Most of the 13 known species of Laophontodes can be characterised by distinct apomorphies. However, phylogenetic comparison highlights some uncertainties due to the apparent heterogeneous distribution of some derived characters across the species, the weakness of other features, and the fragmentary and inadequate description of several species, which, in combination with the unavailability of type material, prevents a detailed comparison of several phylogenetically relevant characters. Thus, the analysis presented here provides a further step towards understanding the systematic relationships of and within Laophontodes, rather than a conclusive answer. Nonetheless, a detailed character discussion and a key to species are given.

Revision of Pleuroprion zur Strassen, 1903 (Holidoteidae) and re-evaluation of Spectrarcturus Schultz, 1981 (Arcturidae) (Crustacea, Isopoda, Valvifera).

Pleuroprion zur Strassen, 1903 is revised and restricted to its type species, Antares chuni zur Strassen, 1902, which is redescribed, using the type material from the German Deep-Sea Expedition in 1898-1899 and more recent material. Pleuroprion is transferred to Holidoteidae Wägele, 1989. Pleuroprion frigidum Hansen, 1916 is transferred to Astacilla Cordiner, 1793 (Arcturidae), while all other species previously placed in Pleuroprion, i.e. P. murdochi (Benedict, 1898), P. chlebovitschi Kussakin, 1972, P. fabulosum Gujanova, 1955, P. furcatum Kussakin, 1982, P. hystrix (Sars, 1877), P. intermedium (Richardson, 1899), P. iturupicum Kussakin Mezhov, 1979 and P. toporoki Kussakin, 1972, are transferred to Spectrarcturus Schultz, 1981 (Arcturidae). The type species of Spectrarcturus, S. multispinatus Schultz, 1981, is a subjective junior synonym of Arcturus murdochi Benedict, 1898, now S. murdochi comb. nov. Spectrarcturus murdochi (Benedict, 1898) is redescribed on the basis of its type material and new material from South Greenland.

A new species of Psammonitocrella Huys, 2009 (Copepoda, Harpacticoida, Ameiridae) from California (USA), with a discussion of the relationship between Psammonitocrella and Parastenocarididae.

The freshwater harpacticoid Psammonitocrella kumeyaayi sp. nov. from the Nearctic Region (California; USA) is proposed. The position of the genus within Harpacticoida and its relationship with the Parastenocarididae is discussed. The new species can be included within Psammonitocrella on account of a) the cylindrical furca, longer than the telson, b) the unmodified inner spine on the basis of the male first leg, c) loss of the outer spine on the second exopodal segment of the first leg, d) loss of the outer spine of the third exopodal segment of the second, third, and fourth legs, e) loss of the inner apical seta on the third exopodal segment of the second and third legs, f) transformation of the inner apical seta of the third exopodal segment of the fourth leg into a spine, and g) loss of the endopodite of the fourth leg. The new species differs remarkably from P. boultoni, and P. longifurcata in the loss of the outer spine of the second exopodal segment of the fourth leg, in the presence of a one-segmented fifth leg exopodite, and in the presence of an outer seta on the basis of the first and second legs. Both Psammonitocrella and the known species of Parastenocarididae have a one-segmented endopod on the fourth leg, and the endopods of the second and third legs are reduced to one or two segments. Psammonitocrella is currently allocated into the Ameiridae, and evidence suggesting a sister-group relationship with Parastenocarididae-both share the loss of the inner seta on the first endopodal segment of the first leg-indicates that the Parastenocarididae should be included into the Ameiridae. In an evolutionary context, Parastenocarididae could have evolved from a lineage of freshwater ameirids that became interstitial in continental waters and colonized aquifers and groundwaters.

A new species of Clausidium Kossmann, 1874 (Copepoda: Cyclopoida) associated with ghost shrimps from the Persian Gulf, including female-male interlocking mechanisms and remarks on host specificity.

A new clausidiid copepod was found associated with the ghost shrimp Neocallichirus jousseaumei (Nobili) in the Persian Gulf, on the Iranian coast. The new species shares the armature formula of swimming legs 2 to 4 with C. persiaensis, but can be easily distinguished from its congeners by unique characteristics of the females: the prominent spine on endopodal segment 1 of the antenna, the armature of the maxilliped, and the elongated basis of the swimming legs. Distinguishing features observed in males include the distinct projections on the maxilliped and the armature of legs 1 and 4. In addition to traditional light microscopy-based descriptions, confocal laser scanning microscopy (CLSM) was used to obtain high resolution images and 3-D reconstructions of entire copepods. Structures of taxonomic importance that exhibit complex shapes (male maxilliped and female urosome) were scanned to generate 3-D prints that gave valuable insights about female/male interlocking mechanisms. The taxonomic status and host specificity of Clausidium spp. are discussed and a key to valid species is provided.

Lectotype designation and distribution updates on the freshwater shrimp species Atyaephyra stankoi Karaman 1972.

Atyaephyra stankoi's Karaman 1972 syntypic material has been assumed to be lost. However, M. Karaman's type material has been found within the zoological collections of the University of Novi Sad, Serbia and thus a lectotype is herein designated, while placing aside the designated neotype. An updated distribution of A. stankoi in Greece and F.Y.R.O.M. is provided based on field collections and literature data, while support is provided by COI data. Furthermore, new records in Peloponnesus and Attica expand the known distribution of species in Greece. Finally some preliminary insights are given on the species zoogeography, while there seems to be a correspondence between genetic haplotype groups and geographical location.