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The Late Jurassic elasmobranch Protospinax annectans is often regarded as a key species to our understanding of crown group elasmobranch interrelationships and the evolutionary history of this group. However, since its first description more than 100 years ago, its phylogenetic position within the Elasmobranchii (sharks and rays) has proven controversial, and a closer relationship between Protospinax and each of the posited superorders (Batomorphii, Squalomorphii, and Galeomorphii) has been proposed over the time. Here we revise this controversial taxon based on new holomorphic specimens from the Late Jurassic Konservat-Lagerstätte of the Solnhofen Archipelago in Bavaria (Germany) and review its skeletal morphology, systematics, and phylogenetic interrelationships. A data matrix with 224 morphological characters was compiled and analyzed under a molecular backbone constraint. Our results indicate a close relationship between Protospinax, angel sharks (Squatiniformes), and saw sharks (Pristiophoriformes). However, the revision of our morphological data matrix within a molecular framework highlights the lack of morphological characters defining certain groups, especially sharks of the order Squaliformes, hampering the phylogenetic resolution of Protospinax annectans with certainty. Furthermore, the monophyly of modern sharks retrieved by molecular studies is only weakly supported by morphological data, stressing the need for more characters to align morphological and molecular studies in the future.

ObjectiveControlled data on predictors of subjective sleep quality in patients with memory complaints are sparse. To improve the amount of comprehensive data on this topic, we assessed factors associated with subjective sleep quality in patients from our memory clinic and healthy individuals.MethodsBetween February 2012 and August 2014 patients with mild cognitive impairment (MCI) and subjective cognitive decline (SCD) from our memory clinic and healthy controls were recruited. Apart from a detailed neuropsychological assessment, the subjective sleep quality, daytime sleepiness and depressive symptoms were assessed using the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale (ESS) and the Beck Depression Inventory (BDI-II).ResultsOne hundred fifty eight consecutive patients (132 (84%) MCI patients and 26 (16%) SCD patients) and 75 healthy controls were included in the study. Pairwise comparison of PSQI scores showed that non-amnestic MCI (naMCI) patients (5.4 ± 3.5) had significantly higher PSQI scores than controls (4.3 ± 2.8, p = .003) Pairwise comparison of PSQI subscores showed that naMCI patients (1.1 ± 0.4) had significantly more "sleep disturbances" than controls (0.9 ± 0.5, p = .003). Amnestic MCI (aMCI) (0.8 ± 1.2, p = .006) and naMCI patients (0.7 ± 1.2, p = .002) used "sleep medication" significantly more often than controls (0.1 ± 0.6) Both, aMCI (11.5 ± 8.6, p < .001) and naMCI (11.5 ± 8.6, p < .001) patients showed significantly higher BDI-II scores than healthy controls (6.1 ± 5.3). Linear regression analysis showed that the subjective sleep quality was predicted by depressive symptoms in aMCI (p < .0001) and naMCI (p < .0001) patients as well as controls (p < .0001). This means, that more depressive symptoms worsened subjective sleep quality. In aMCI patients we also found a significant interaction between depressive symptoms and global cognitive function (p = .002).DiscussionDepressive symptoms were the main predictor of subjective sleep quality in MCI patients and controls, but not in SCD patients. Better global cognitive function ameliorated the negative effect of depressive symptoms on the subjective sleep quality in aMCI patients.

Abstract  Palaeospinacids are a group of basal galeomorph sharks and are placed in the order Synechodontiformes (Chondrichthyes, Neoselachii) ranging from the Permian to the Eocene. Currently, there is a controversy concerning the identity of diagnostic characters for distinguishing palaeospinacid genera because of very similar dental morphologies and the scarcity of articulated skeletal material. The most notable character for distinguishing species within the Palaeospinacidae is, however, the dental morphology. The main dental character uniting all palaeospinacids is the very specialised pseudopolyaulacorhize root vascularisation. A re-examination of articulated neoselachian skeletons from the Lower Jurassic of Lyme Regis (England) and Holzmaden (S Germany), and recently discovered specimens from the Upper Jurassic of the Solnhofen area and Nusplingen (S Germany) has yielded several hitherto unrecognised complete skeletons of the palaeospinacids Synechodus and Paraorthacodus enabling a re-evaluation of characters. These specimens indicate that the number of dorsal fins and the presence or absence of dorsal fin spines represent important features for identifying palaeospinacids. Synechodus bears two dorsal fins without fin spines, whereas Paraorthacodus only has a single dorsal fin lacking a fin spine directly in front of the caudal fin. All palaeospinacids from the Early Jurassic have two spines supporting the dorsal fins and are consequently assigned to a new genus, Palidiplospinax nov. gen. Three species are placed into the new taxon: Synechodus enniskilleni, S. occultidens and S. smithwoodwardi. [ABSTRACT FROM AUTHOR]

We describe the first known occurrence of a Permian shark specimen preserving two temnospondyl amphibians in its digestive tract as well as the remains of an acanthodian fish, which was ingested by one of the temnospondyls. This exceptional find provides for the first time direct evidence of a vertebrate three-level food chain in the fossil record with the simultaneous preservation of three trophic levels. Our analysis shows that small-sized Lower Permian xenacanthid sharks of the genus Triodus preyed on larval piscivorous amphibians. The recorded trophic interaction can be explained by the adaptation of certain xenacanthids to fully freshwater environments and the fact that in these same environments, large temnospondyls occupied the niche of modern crocodiles. This unique faunal association has not been documented after the Permian and Triassic. Therefore, this Palaeozoic three-level food chain provides strong and independent support for changes in aquatic trophic chain structures through time. [ABSTRACT FROM AUTHOR]