Zur Feinstruktur der spermatogenetischen Stadien von Myxine glutinosa L. (Cyclostomata)

The fine structure of the spermatogonia, spermatocytes, spermatids, the Sertoli cell and the epithelial cells of the mesorchial sheath is described. In an early spermatid stage a transient close relationship between the Chromatoid body and the acrosome is demonstrated.     

Projecting climate change impacts on species distributions in megadiverse South African Cape and Southwest Australian Floristic Regions: Opportunities and challenges

Increasing evidence shows that anthropogenic climate change is affecting biodiversity. Reducing or stabilizing greenhouse gas emissions may slow global warming, but past emissions will continue to contribute to further unavoidable warming for more than a century. With obvious signs of difficulties in achieving effective mitigation worldwide in the short term at least, sound scientific predictions of future impacts on biodiversity will be required to guide conservation planning and adaptation. This is especially true in Mediterranean type ecosystems that are projected to be among the most significantly affected by anthropogenic climate change, and show the highest levels of confidence in rainfall projections. Multiple methods are available for projecting the consequences of climate change on the main unit of interest – the species – with each method having strengths and weaknesses. Species distribution models (SDMs) are increasingly applied for forecasting climate change impacts on species geographic ranges. Aggregation of models for different species allows inferences of impacts on biodiversity, though excluding the effects of species interactions. The modelling approach is based on several further assumptions and projections and should be treated cautiously. In the absence of comparable approaches that address large numbers of species, SDMs remain valuable in estimating the vulnerability of species. In this review we discuss the application of SDMs in predicting the impacts of climate change on biodiversity with special reference to the species‐rich South West Australian Floristic Region and South African Cape Floristic Region. We discuss the advantages and challenges in applying SDMs in biodiverse regions with high levels of endemicity, and how a similar biogeographical history in both regions may assist us in understanding their vulnerability to climate change. We suggest how the process of predicting the impacts of climate change on biodiversity with SDMs can be improved and emphasize the role of field monitoring and experiments in validating the predictions of SDMs.     

Management-Induced Reproductive Failure and Breeding Dispersal in Double-Crested Cormorants on Lake Champlain

ABSTRACT We studied breeding dispersal of double-crested cormorants (Phalacrocorax auritus) associated with management practices that suppressed their reproduction on Lake Champlain in the northeastern United States. We implemented an experiment on one colony by spraying corn oil on cormorant eggs in portions of the colony and leaving other portions untreated. Gulls (Larus spp.) consumed cormorant eggs during the oiling process, but we reduced and then eliminated predation levels after the first year of the study. We used mark-recapture techniques within the experimental framework to measure rates of breeding dispersal for cormorants from the experimental colony and an unmanaged colony in Lake Champlain. Egg oiling increased the movement rate to the unmanaged colony by 3% during the year with no egg predation by gulls. When gulls depredated cormorant eggs at high rates during egg oiling, movement to the unmanaged colony increased by 20%. When cormorants are managed to reduce population sizes, methods that limit dispersal away from the managed colony may be most effective. Such methods would mitigate effects to nontarget populations and allow for a greater portion of the metapopulation to be managed.     

Alesiella gen.n. and a newly discovered relict lineage of Staphylinini (Coleoptera: Staphylinidae)

This study aimed to identify the sister group of the poorly known and morphologically isolated Burmese species Quedius lineipennis within the tribe Staphylinini (Staphylinidae: Staphylininae) using morphological characters. Phylogenetic analysis of a broad taxon sample demonstrated that this Asian species is not a member of the genus Quedius but forms the sister taxon to the Neotropical genus Quediomacrus. Both taxa were shown to be members of a hitherto unrecognized lineage with a highly disjunct distribution. The lineage is hypothesized to be Asian in origin, with dispersals to the Americas during the early Eocene climatic maximum via Beringia and to Australia via land connections in the late Miocene. The current distribution of the lineage is considered to be relictual. New phylogenetic hypotheses within ‘Quediina’ and Staphylinini as a whole are proposed and the general tree topology of Staphylinini recovered by recent morphological studies is refined. Phylogenetic relationships within the Quedius complex remain unclear. Alesiella Brunke and Solodovnikov gen.n. , is erected for Quedius lineipennis and the Quedius subgenus Quedionuchus is reinstated to genus level with new combinations as follows: Quedionuchus atl (Smetana, 1975), comb.n. ; Quedionuchus calli (Smetana, 1976), comb.n. ; Quedionuchus cipactli (Smetana, 1976), comb.n. ; Quedionuchus coatl (Smetana, 1976), comb.n. ; Quedionuchus ehacatl (Smetana, 1976), comb.n. ; Quedionuchus ollin (Smetana, 1976), comb.n. ; Quedionuchus ozomatli (Smetana, 1975), comb.n. ; Quedionuchus reitterianus (Bernhauer, 1944), comb.n. ; Quedionuchus samuraicus (Bernhauer and Schubert, 1916), comb.n. ; Quedionuchus schultzei (Smetana, 1975), comb.n. ; Quedionuchus tecpatl (Smetana, 1976), comb.n. ; Quedionuchus xochitl (Smetana, 1976). Quedius lugubris Lokay, 1913 is transferred from the subgenus Quedionuchus to the subgenus Distichalius and placed in synonymy: Quedius punctatellus (Heer, 1839) = Quedius lugubris Lokay, 1913, syn.n . This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:9C7D3C90‐FCB9‐414F‐911B‐194A1A6602DE .     

HORIZONTAL ANGULAR DISCRIMINATION BY AN ECHOLOCATING BOTTLENOSE DOLPHIN TURSIOPS TRUNCATUS

ABSTRACT

A bottlenose dolphin was tested on its ability to echoically discriminate horizontal angular differences between two arrays of vertical, air-filled, PVC rods. The blindfolded dolphin was required to station in a submerged, vertically-oriented hoop, 2 radial metres from the stimuli, and indicate whether an array with four rods (S+) was to the left or the right of an array with two rods (S-), by pressing a corresponding paddle. The angular separation between the rods within each array (θ_w) was maintained at 2 degrees but the angular separation between the two arrays (θ_b) was varied to produce angular differences (δθ = θ_b-θ_w)ranging from 0.25 degrees to 4 degrees. A modified method of constant stimuli was used to test for angular discrimination ability, and yielded a psychometric function having a 75% correct threshold of 1.6 degrees. This threshold fell between the passive listening minimum audible angle thresholds of 0.9 degrees for click signals and 2.1 degrees for a pure tone signal (Renaud & Popper 1975). Analyses of response times, number of clicks and inter-click intervals failed to detect any significant adaptive behaviour occurring as the task became more difficult. These results help to define angular resolution capabilities of dolphin sonar that may play an important role in representing spatial information in the dolphin's environment.     

A new genus of pliosaur (Reptilia: Sauropterygia) from the Lower Jurassic of Holzmaden,Germany

Abstract: The exquisitely preserved holotype of the pliosaur ‘Rhomaleosaurus’victor (SMNS 12478) is described from the Toarcian Posidonien‐Schiefer (Upper Lias, Lower Jurassic) of Holzmaden (Baden‐Württemberg), Germany. The specimen presents a novel combination of synapomorphies and unique morphometric proportions separating it from Rhomaleosaurus sensu stricto and warranting the erection of a new genus, Meyerasaurus gen. nov. Historically, the name ‘Thaumatosaurus’ has been interchangeable with Rhomaleosaurus and is frequently associated with SMNS 12478 in the literature. However, this is an invalid taxon and cannot be reinstated. The anatomy of Meyerasaurus victor is compared in detail with other pliosaurs, and its taxonomic affinity is reviewed. M. victor belongs to the family Rhomaleosauridae and shares several anatomical characters with Rhomaleosaurus including a short and robust premaxillary rostrum (length‐to‐width ratio c. 1.0), parallel premaxilla–maxilla sutures anterior to the nares, vomers contacting the maxillae posterior to the internal nares, and c. 28 cervical vertebrae minus the atlas–axis. The known geographical distribution of Rhomaleosaurus, which previously extended across the German and English palaeobiogeographical zones, is reduced to the English zone as a consequence of the referral of SMNS 12478 to a new genus. This is significant because it contributes to an ongoing trend of increasing generic separation between the German and English zones, while increasing the generic diversity within the German zone itself.