A critical appraisal of appendage disparity and homology in fishes

Fishes are both extremely diverse and morphologically disparate. Part of this disparity can be observed in the numerous possible fin configurations that may differ in terms of the number of fins as well as fin shapes, sizes and relative positions on the body. Here, we thoroughly review the major patterns of disparity in fin configurations for each major group of fishes and discuss how median and paired fin homologies have been interpreted over time. When taking into account the entire span of fish diversity, including both extant and fossil taxa, the disparity in fin morphologies greatly complicates inferring homologies for individual fins. Given the phylogenetic scope of this review, structural and topological criteria appear to be the most useful indicators of fin identity. We further suggest that it may be advantageous to consider some of these fin homologies as nested within the larger framework of homologous fin‐forming morphogenetic fields. We also discuss scenarios of appendage evolution and suggest that modularity may have played a key role in appendage disparification. Fin modules re‐expressed within the boundaries of fin‐forming fields could explain how some fins may have evolved numerous times independently in separate lineages (e.g., adipose fin), or how new fins may have evolved over time (e.g., anterior and posterior dorsal fins, pectoral and pelvic fins). We favour an evolutionary scenario whereby median appendages appeared from a unique field of competence first positioned throughout the dorsal and ventral midlines, which was then redeployed laterally leading to paired appendages.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151971/1/faf12402_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151971/2/faf12402.pd

Attitude of vilnius university medical students towards organ donation and body donation to science

Attitude of Vilnius University Medical Students Towards Organ Donation and Body Donation to Science Substantiation: Although donation rates are growing, the worldwide shortage of organ donors is still identified as a major problem. Each day, on average, 11 people die while waiting for a transplant. And while the idea of organ donation in our society is becoming more acceptable, the subject of body donation to science remains highly problematic. To increase the number of donors is an important public health problem. Students as future healthcare professionals, is an example that can increase public acceptance of organ and body donation. Objective: to assess the attitude of Vilnius University Faculty of Medicine students' towards organ donation and body donation to science. Aims: 1) to evaluate students' attitude towards organ donation from living and deceased human being; 2) to evaluate students' attitude towards body donation to science; 3) to assess their socio-demographic factors and attitudes towards donation interfaces; 4)to evaluate students' approach to the dissemination of the donation in the media. Methods: 367 student of Vilnius University Faculty of Medicine was surveyed using an anonymous survey method. Data analysis was done by SPSS v. 24.0 and Microsoft Office Excel 2010 programs. To define the difference between statistical signs were used &#967;2 squared test. For the questions which consists an interval scale was used Mann-Whitney U test and when compared more than 2 groups – Kruskal Wallis test. The difference was considered statistically significant at p < 0,05. Results and conclusions: The majority of Faculty of Medicine student understands the term "organ donation" and supports the idea it. The donation from a deceased human is supported more than from a live human (98.4% and 93.2%). 83.1% students would agree to become organ donors. Men and non-religious people are more likely to agree with it. 70.1% of students would tend to have organ donor card. More often medical students and non-religious people. Students would mostly agree to donate their kidneys, liver, lungs and heart, less often - their cornea and skin. The main reasons why students would agree to become organ donors are because they feel an obligation to help others (64.6%) and belief that as their death will not be meaningless (58.9%). The belief that it would hurt their loved ones (16.3 percent.) is the main reason why students would refuse to become a donor. Only slightly more than half of the students (56.9%) tend to talk about organ donation with their families. The majority of respondents (73.6%) agreed that the donor's relatives can give consent to organ donation, if the donor is dead. Most students information about organ donation received from the media (71.4%) and 95.4% respondents felt that Lithuania lacks objective information on organ donation. Vast majority of students understands the term "body donation to science” and supports idea of it , but only one-third (31.1%) of students would agree to become a body donor. Women are more likely to refuse to become body donor. The main reason for the refusal is the fear that their body will be treated disrespectfully. This reason is pointed out more often by medicine and senior students. The main cause of consent is the desire to be useful to humanity, future generations, education (47.7%). Most of the students information about body donation received in university (82.0%). The majority of respondents felt that more objective information on body donation is needed in Lithuania. Keywords: organ donation, body donation to science, students, attitud

Escamas de telodontos del Devónico Inferior del Archipiélago Novaya Zemlya, Rusia ártica

Scales of a new thelodont species, Amaltheolepis terranovi sp. nov., are described from the upper Emsian, Lower Devonian Shevchenkinskaya Formation of Novaya Zemlya, Arctic Russia. The new species shows strong resemblance with the Emsian “Verdalen assemblage” from Spitsbergen, supporting an Emsian age for the upper part of the Shevchenkinskaya Formation. This conclusion in the context of the various Amaltheolepis assemblages from Spitsbergen, allows for a more accurate comparison and correlation between assemblages from different regions in the Northern Hemisphere, suggesting that the type species, Amaltheolepis winsnesi from Spitsbergen, is Eifelian in age