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1.
BMC Psychol ; 12(1): 267, 2024 May 13.
Article in English | MEDLINE | ID: mdl-38741197

ABSTRACT

BACKGROUND: The aim of this research was to analyze whether the personality factors included in the Big Five model differentially predict the self-regulation and affective states of university students and health. METHODS: A total of 637 students completed validated self-report questionnaires. Using an ex post facto design, we conducted linear regression and structural prediction analyses. RESULTS: The findings showed that model factors were differential predictors of both self-regulation and affective states. Self-regulation and affective states, in turn, jointly predict emotional performance while learning and even student health. These results allow us to understand, through a holistic predictive model, the differential predictive relationships of all the factors: conscientiousness and extraversion were predictors regulating positive emotionality and health; the openness to experience factor was non-regulating; nonregulating; and agreeableness and neuroticism were dysregulating, hence precursors of negative emotionality and poorer student health. CONCLUSIONS: These results are important because they allow us to infer implications for guidance and psychological health at university.


Subject(s)
Adaptation, Psychological , Emotions , Health Behavior , Personality , Self-Control , Students , Humans , Students/psychology , Students/statistics & numerical data , Female , Male , Universities , Young Adult , Self-Control/psychology , Adult , Adolescent , Surveys and Questionnaires , Academic Success
2.
Molecules ; 28(13)2023 Jun 21.
Article in English | MEDLINE | ID: mdl-37446548

ABSTRACT

The metalloporphyrin heme acts as the oxygen-complexing prosthetic group of hemoglobin in blood. Heme has been noted to survive for many millions of years in fossils. Here, we investigate its stability and degradation under various conditions expected to occur during fossilization. Oxidative, reductive, aerobic, and anaerobic conditions were studied at neutral and alkaline pH values. Elevated temperatures were applied to accelerate degradation. High-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) identified four main degradation products. The vinyl residues are oxidized to formyl and further to carboxylate groups. In the presence of air or H2O2, cleavage of the tetrapyrrole ring occurs, and hematinic acid is formed. The highest stability of heme was observed under anaerobic reductive conditions (half-life 9.5 days), while the lowest stability was found in the presence of H2O2 (half-life 1 min). We confirmed that the iron cation plays a crucial role in degradation, since protoporphyrin IX, lacking iron, remained significantly more stable. Under anaerobic, reductive conditions, the above-mentioned degradation products were not observed, suggesting a different degradation pathway. To our knowledge, this is the first molecular taphonomy study on heme, which will be useful for understanding its fate during fossilization.


Subject(s)
Heme , Hemin , Heme/chemistry , Hemin/chemistry , Tandem Mass Spectrometry , Hydrogen Peroxide/chemistry , Paleontology , Iron/chemistry , Oxidation-Reduction
4.
JMIR Form Res ; 7: e38500, 2023 Jan 25.
Article in English | MEDLINE | ID: mdl-36512402

ABSTRACT

BACKGROUND: Although physical activity can mitigate disease trajectories and improve and sustain mental health, many people have become less physically active during the COVID-19 pandemic. Personal information technology, such as activity trackers and chatbots, can technically converse with people and possibly enhance their autonomous motivation to engage in physical activity. The literature on behavior change techniques (BCTs) and self-determination theory (SDT) contains promising insights that can be leveraged in the design of these technologies; however, it remains unclear how this can be achieved. OBJECTIVE: This study aimed to evaluate the feasibility of a chatbot system that improves the user's autonomous motivation for walking based on BCTs and SDT. First, we aimed to develop and evaluate various versions of a chatbot system based on promising BCTs. Second, we aimed to evaluate whether the use of the system improves the autonomous motivation for walking and the associated factors of need satisfaction. Third, we explored the support for the theoretical mechanism and effectiveness of various BCT implementations. METHODS: We developed a chatbot system using the mobile apps Telegram (Telegram Messenger Inc) and Google Fit (Google LLC). We implemented 12 versions of this system, which differed in 3 BCTs: goal setting, experimenting, and action planning. We then conducted a feasibility study with 102 participants who used this system over the course of 3 weeks, by conversing with a chatbot and completing questionnaires, capturing their perceived app support, need satisfaction, physical activity levels, and motivation. RESULTS: The use of the chatbot systems was satisfactory, and on average, its users reported increases in autonomous motivation for walking. The dropout rate was low. Although approximately half of the participants indicated that they would have preferred to interact with a human instead of the chatbot, 46.1% (47/102) of the participants stated that the chatbot helped them become more active, and 42.2% (43/102) of the participants decided to continue using the chatbot for an additional week. Furthermore, the majority thought that a more advanced chatbot could be very helpful. The motivation was associated with the satisfaction of the needs of competence and autonomy, and need satisfaction, in turn, was associated with the perceived system support, providing support for SDT underpinnings. However, no substantial differences were found across different BCT implementations. CONCLUSIONS: The results provide evidence that chatbot systems are a feasible means to increase autonomous motivation for physical activity. We found support for SDT as a basis for the design, laying a foundation for larger studies to confirm the effectiveness of the selected BCTs within chatbot systems, explore a wider range of BCTs, and help the development of guidelines for the design of interactive technology that helps users achieve long-term health benefits.

5.
Front Psychol ; 13: 922633, 2022.
Article in English | MEDLINE | ID: mdl-36389553

ABSTRACT

The self- vs. external-regulation behavior theory, SR-ER Theory (2021) model has postulated the Self-Regulation /Non or De-Regulation/Dys-regulation (SR-NR-DR) continuum in the person and in their context. The model also generates a behavioral heuristic that allows us to predict and explain the variability of other dependent behavioral variables in a range of scenarios (clinical, educational, health and technology contexts). Consequently, the objective of this study was to validate the different scales prepared on the basis of the theory presented. A total of 469 students voluntarily completed at different times the five questionnaires presented, to give a total of 1,385 completed questionnaires. Using an ex post facto design, descriptive, correlational, confirmatory factorial analysis (CFA), reliability, and concurrent validity analyses were carried out. The scales were analyzed individually and as a whole. The results showed the acceptable structure of scale and consistent levels of reliability. The five levels generated by the SR-NR-DR (personal and contextual) combinatory heuristic that arises from the theoretical model determined significant differences in the levels of the variables analyzed for each psychological context. We discuss the theoretical implications and the implications for the assessment and improvement of the behaviors analyzed in function of the personal and contextual regulation levels evaluated.

6.
Front Psychol ; 13: 861493, 2022.
Article in English | MEDLINE | ID: mdl-35910968

ABSTRACT

The aim of this paper is to demonstrate how Bandura's Social Cognitive Theory (1986) influenced the development of several complementary models of the construct of Self-Regulation. Building on the foundation of Self-Determination Theory, SDT (2000), and Zimmerman's Self-Regulation Theory, SR (2001), with their assumptions, contributions, goddesses, and limitations, we come to the Self- vs. External Regulatory Theory, SR-ER (2021). Finally, we integrate recent evidence demonstrating the explanatory adequacy of the SR vs. ER model for different psychological constructions in different settings related to education, health, clinical practice and social work. Complementary, a new theoretical and empirical research agenda is presented, to continue testing the adequacy of SR vs. ER assumptions, and to better understand the behavioral variability of the different constructs studied.

7.
Biology (Basel) ; 11(5)2022 Apr 27.
Article in English | MEDLINE | ID: mdl-35625398

ABSTRACT

This review provides an overview of organic compounds detected in non-avian dinosaur fossils to date. This was enabled by the development of sensitive analytical techniques. Non-destructive methods and procedures restricted to the sample surface, e.g., light and electron microscopy, infrared (IR) and Raman spectroscopy, as well as more invasive approaches including liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), time-of-flight secondary ion mass spectrometry, and immunological methods were employed. Organic compounds detected in samples of dinosaur fossils include pigments (heme, biliverdin, protoporphyrin IX, melanin), and proteins, such as collagens and keratins. The origin and nature of the observed protein signals is, however, in some cases, controversially discussed. Molecular taphonomy approaches can support the development of suitable analytical methods to confirm reported findings and to identify further organic compounds in dinosaur and other fossils in the future. The chemical properties of the various organic compounds detected in dinosaurs, and the techniques utilized for the identification and analysis of each of the compounds will be discussed.

8.
Front Psychol ; 12: 602904, 2021.
Article in English | MEDLINE | ID: mdl-33643135

ABSTRACT

The combination of student Self-Regulation (SR) and the context of Regulatory Teaching (RT), each in varying degree, has recently been demonstrated to have effects on achievement emotions, factors and symptoms of stress, and coping strategies. The aim of the present research study is to verify its possible further effects, on academic behavioral confidence and procrastination. A total of 1193 university students completed validated online questionnaires with regard to specific subjects in their degree program. Using an ex post facto design, multivariate analyses and structural equation modeling (SEM) were carried out in order to test the relationships predicted by the model. SR and RT had a significant joint effect in determining the degree of academic behavioral confidence and of procrastination. Academic behavioral confidence also significantly predicted reasons for procrastinating, and these in turn predicted activities of procrastination. Conclusions are discussed, insisting on the combined weight of the two variables in determining academic behavioral confidence, reasons for procrastinating and activities subject to procrastination, in university students. Implications for guidance and educational support of university students and teachers are analyzed.

9.
Front Psychol ; 11: 543884, 2020.
Article in English | MEDLINE | ID: mdl-33117221

ABSTRACT

The aim of this research was to determine the degree to which undergraduate students' learning approach, academic achievement and satisfaction were determined by the combination of an intrapersonal factor (self-regulation) and a interpersonal factor (contextual or regulatory teaching). The hypothesis proposed that greater combined regulation (internal and external) would be accompanied by more of a deep approach to learning, more satisfaction and higher achievement, while a lower level of combined regulation would determine a surface approach, less satisfaction and lower achievement. Within an ex post facto design by selection, 1036 university students completed validated questionnaires using an online tool. Several multivariate analyses were conducted. Results showed that the combination of self-regulation and external regulation can be ordered as levels along a five-point scale or heuristic. These levels linearly determine type of learning approach, academic achievement and satisfaction. Implications are established for quality and improvement of the teaching and learning process at university.

10.
Front Psychol ; 11: 1773, 2020.
Article in English | MEDLINE | ID: mdl-32982819

ABSTRACT

The SRL vs. ERL theory has shown that the combination of levels of student self-regulation and regulation from the teaching context produces linear effects on achievement emotions and coping strategies. However, a similar effect on stress factors and symptoms of university students has not yet been demonstrated. The aim of this study was to test this prediction. It was hypothesized that the level of student self-regulation (low/medium/high), in interaction with the level of external regulation from teaching (low/medium/high), would also produce a linear effect on stress factors and symptoms of university students. A total of 527 undergraduate students completed validated questionnaires about self-regulation, regulatory teaching, stress factors, and symptoms. Using an ex post facto design by selection, ANOVAs and MANOVAs (3 × 3; 5 × 1; 5 × 2) were carried out. The results confirmed that the level of self-regulation and the level of regulatory teaching jointly determined the level of stress factors and symptoms of university students. Once again, a five-level heuristic of possible combinations was configured to jointly determine university students' level of academic stress. We concluded that the combination of different levels of student regulation and regulation from the teaching process jointly determines university students' level of academic stress. The implications for university students' emotional health, stress prevention, and well-being are established.

11.
Article in English | MEDLINE | ID: mdl-32752246

ABSTRACT

Within a socio-situational and socio-behavioural context, the relationships between the Big Five personality traits and the academic confidence of university students and how they differed by sex of the student was explored. Previous research has identified both conscientiousness and academic confidence as being linked to university performance. In respect of sex, female students have been found to score higher on all of the Big Five measures, whereas the relationship between sex and academic confidence has been mixed. Using self-report measures of personality and academic confidence from 1523 Spanish students, it was found that the female students were more confident in their grades, studying and attendance components of academic confidence and had higher scores for conscientiousness, agreeableness and neuroticism personality measures. A multiple regression analysis found that personality predicts academic confidence, with conscientiousness being the trait that statistically loaded the most strongly. This research further confirms the validity of the Academic Behavioural Confidence scale and suggests that measures of personality and, especially, academic confidence could be usefully used in student support situations to help students acquire the strategies and skills that lead to successful university study. It is suggested that further research in the area needs to include outcome or achievement measures and measures of hypothetical constructs, such as personality and academic confidence, that go beyond self-report measures.


Subject(s)
Academic Success , Personality Disorders , Personality , Students , Achievement , Adolescent , Adult , Female , Humans , Male , Middle Aged , Sex Factors , Universities , Young Adult
12.
Article in English | MEDLINE | ID: mdl-32443929

ABSTRACT

The study focused on the analysis of linear relations between personality, self-regulation, coping strategies and achievement emotions. The main objective was to establish a model of linear, empirical, associative to infer needs and proposals for intervening in emotional health in the different profiles of university students. A total of 642 undergraduate students participated in this research. Evidence of associative relations between personality factors, self-regulation and coping strategies was found. The neuroticism factor had a significant negative associative relationship with Self-Regulation both globally and in its factors; especially important was its negative relation to decision making, and coping strategies focused in emotion. The results of Structural Equation Model showed an acceptable model of relationships, in each emotional context. Results and practical implications are discussed.


Subject(s)
Academic Success , Adaptation, Psychological , Emotions , Students , Humans , Personality , Students/psychology
13.
J Lipid Res ; 60(9): 1516-1534, 2019 09.
Article in English | MEDLINE | ID: mdl-31239285

ABSTRACT

NMR-based quantification of human lipoprotein (sub)classes is a powerful high-throughput method for medical diagnostics. We evaluated select proton NMR signals of serum lipoproteins for elucidating the physicochemical features and the absolute NMR visibility of their lipids. We separated human lipoproteins of different subclasses by ultracentrifugation and analyzed them by 1H NMR spectroscopy at different temperatures (283-323 K) and pressures (0.1-200 MPa). In parallel, we determined the total lipid content by extraction with chloroform/methanol. The visibility of different lipids in the 1H NMR spectra strongly depends on temperature and pressure: it increases with increasing temperatures but decreases with increasing pressures. Even at 313 K, only part of the lipoprotein is detected quantitatively. In LDL and in HDL subclasses HDL2 and HDL3, only 39%, 62%, and 90% of the total cholesterol and only 73%, 70%, and 87% of the FAs are detected, respectively. The choline head groups show visibilities of 43%, 75%, and 87% for LDL, HDL2, and HDL3, respectively. The description of the NMR visibility of lipid signals requires a minimum model of three different compartments, A, B, and C. The thermodynamic analysis of compartment B leads to melting temperatures between 282 K and 308 K and to enthalpy differences that vary for the different lipoproteins as well as for the reporter groups selected. In summary, we describe differences in NMR visibility of lipoproteins and variations in biophysical responses of functional groups that are crucial for the accuracy of absolute NMR quantification.


Subject(s)
Lipoproteins/analysis , Magnetic Resonance Spectroscopy/methods , Lipoproteins, IDL/analysis , Lipoproteins, LDL/analysis , Lipoproteins, VLDL/analysis , Metabolomics , Pressure , Temperature
14.
Radiol Case Rep ; 14(5): 535-537, 2019 May.
Article in English | MEDLINE | ID: mdl-30976364

ABSTRACT

We report a rare case of gadolinium contrast extravasation in a rapidly expanding basal ganglia hemorrhage on magnetic resonance imaging (MRI). Contrast extravasation within an intracerebral hematoma (ICH) on computed tomography (CT) angiography has been described as the "spot sign" and is a well-known indicator of active bleeding; however, contrast extravasation has seldom been reported on MRI. In this case, a 61-year-old female inpatient developed acute left hemiparesis and dysarthria on her third day of hospital admission. An initial noncontrast head CT showed an ICH, increasing in size on the follow-up CT study, and a subsequent MRI brain without and with contrast demonstrated multiple round collections of active bleeding at the margins of the hematoma on the postcontrast images. A CT angiogram performed following the MRI confirmed contrast extravasation along the margins of the hematoma. This case is unique as it demonstrates the "spot sign" with MRI, and the multiple foci of active bleeding identified with MRI support the "avalanche" hypothesis, which proposes that the initial expanding ICH leads to additional arterial ruptures and propagation of bleeding.

15.
Case Rep Radiol ; 2018: 4767516, 2018.
Article in English | MEDLINE | ID: mdl-30345139

ABSTRACT

Internal hernias involve herniation of viscera into an abdominal compartment through a defect in the mesentery or peritoneum. Herniation may occur through normal anatomic structures or through pathologic defects secondary to congenital abnormality, inflammation, trauma, or surgery. Patients with an internal hernia most commonly present with acute bowel obstruction. While internal hernia is an uncommon cause of bowel obstruction, making up approximately 0.2-0.9% of cases (Choi, 2017), the incidence is increasing due to greater use of techniques such as Roux-en-Y for liver transplant and gastric bypass. There are multiple types of internal hernia, including paraduodenal, Foramen of Winslow, sigmoid mesocolon, pericecal, transmesenteric, transomental, supravesical, and pelvic. We present a case in which a transverse colon epiploic appendage adhesion to the ascending colon mesentery resulted in a closed loop obstruction mimicking a pericecal internal hernia. Radiologists should be aware of the imaging findings of closed loop obstruction related to internal hernia and maintain a high index of suspicion in patients with history of prior abdominal surgery presenting with bowel obstruction. It is useful for radiologists to understand that adhesions may result in internal hernias, which mimic the classically described categories.

16.
Eur Spine J ; 27(6): 1266-1271, 2018 06.
Article in English | MEDLINE | ID: mdl-28849400

ABSTRACT

PURPOSE: To determine the prevalence, radiographic features and reporting rate of, and the association between the congenital anterior and posterior C1 arch anomalies. METHODS: The computed tomography (CT) images of the cervical spines of all patients over 18 years who had CT examinations in our hospital during the study period were reviewed to evaluate for congenital anomalies of the anterior and posterior C1 arches. Radiology reports of the corresponding CT examinations were reviewed to determine the reporting rate of these defects. RESULTS: Of 3273 subjects, 185 (5.65%) had congenital atlas anomalies: 169 isolated posterior (5.16%), 15 combined anterior and posterior (bipartite, 0.46%), and one isolated anterior (0.031%) arch defects. Females had a higher prevalence than males (7.46 versus 4.72%, P = 0.0013). Eighty-three cases (44.9%) of C1 arch anomalies were not reported. The Currarino type A, B, C and E posterior arch defects accounted for 81.6, 8.1, 1.1, and 0.5% of all arch anomalies while type D was not observed. Fifteen patients (0.46%) had combined anterior and posterior arch anomalies (bipartite atlas) versus only one with an isolated anterior C1 defect, indicating a significant association between the anterior and posterior arch defects (P < 0.0001). CONCLUSIONS: Although some types of congenital C1 arch anomalies are rare, type A defects are relatively common radiological findings that are unreported approximately 45% of the time. Based on the significant association between the anterior and posterior arch defects, we propose possible mechanisms for the formation of the bipartite atlas.


Subject(s)
Cervical Atlas/abnormalities , Spinal Diseases/epidemiology , Adult , Aged , Aged, 80 and over , Cervical Atlas/diagnostic imaging , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Prevalence , Retrospective Studies , Spinal Diseases/congenital , Tomography, X-Ray Computed/methods , Young Adult
17.
Front Psychol ; 8: 232, 2017.
Article in English | MEDLINE | ID: mdl-28280473

ABSTRACT

The Theory of Self- vs. Externally-Regulated Learning™ (SRL vs. ERL) proposed different types of relationships among levels of variables in Personal Self-Regulation (PSR) and Regulatory Teaching (RT) to predict the meta-cognitive, meta-motivational and -emotional variables of learning, and of Academic Achievement in Higher Education. The aim of this investigation was empirical in order to validate the model of the combined effect of low-medium-high levels in PSR and RT on the dependent variables. For the analysis of combinations, a selected sample of 544 undergraduate students from two Spanish universities was used. Data collection was obtained from validated instruments, in Spanish versions. Using an ex-post-facto design, different Univariate and Multivariate Analyses (3 × 1, 3 × 3, and 4 × 1) were conducted. Results provide evidence for a consistent effect of low-medium-high levels of PSR and of RT, thus giving significant partial confirmation of the proposed rational model. As predicted, (1) the levels of PSR and positively and significantly effected the levels of learning approaches, resilience, engagement, academic confidence, test anxiety, and procedural and attitudinal academic achievement; (2) the most favorable type of interaction was a high level of PSR with a high level RT process. The limitations and implications of these results in the design of effective teaching are analyzed, to improve university teaching-learning processes.

18.
Front Psychol ; 6: 399, 2015.
Article in English | MEDLINE | ID: mdl-25964764

ABSTRACT

The present investigation examines how personal self-regulation (presage variable) and regulatory teaching (process variable of teaching) relate to learning approaches, strategies for coping with stress, and self-regulated learning (process variables of learning) and, finally, how they relate to performance and satisfaction with the learning process (product variables). The objective was to clarify the associative and predictive relations between these variables, as contextualized in two different models that use the presage-process-product paradigm (the Biggs and DEDEPRO models). A total of 1101 university students participated in the study. The design was cross-sectional and retrospective with attributional (or selection) variables, using correlations and structural analysis. The results provide consistent and significant empirical evidence for the relationships hypothesized, incorporating variables that are part of and influence the teaching-learning process in Higher Education. Findings confirm the importance of interactive relationships within the teaching-learning process, where personal self-regulation is assumed to take place in connection with regulatory teaching. Variables that are involved in the relationships validated here reinforce the idea that both personal factors and teaching and learning factors should be taken into consideration when dealing with a formal teaching-learning context at university.

19.
J Cell Mol Med ; 18(7): 1444-59, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24779367

ABSTRACT

Members of the transforming growth factor (TGF)-ß family govern a wide range of mechanisms in brain development and in the adult, in particular neuronal/glial differentiation and survival, but also cell cycle regulation and neural stem cell maintenance. This clearly created some discrepancies in the field with some studies favouring neuronal differentiation/survival of progenitors and others favouring cell cycle exit and neural stem cell quiescence/maintenance. Here, we provide a unifying hypothesis claiming that through its regulation of neural progenitor cell (NPC) proliferation, TGF-ß signalling might be responsible for (i) maintaining stem cells in a quiescent stage, and (ii) promoting survival of newly generated neurons and their functional differentiation. Therefore, we performed a detailed histological analysis of TGF-ß1 signalling in the hippocampal neural stem cell niche of a transgenic mouse that was previously generated to express TGF-ß1 under a tetracycline regulatable Ca-Calmodulin kinase promoter. We also analysed NPC proliferation, quiescence, neuronal survival and differentiation in relation to elevated levels of TGF-ß1 in vitro and in vivo conditions. Finally, we performed a gene expression profiling to identify the targets of TGF-ß1 signalling in adult NPCs. The results demonstrate that TGF-ß1 promotes stem cell quiescence on one side, but also neuronal survival on the other side. Thus, considering the elevated levels of TGF-ß1 in ageing and neurodegenerative diseases, TGF-ß1 signalling presents a molecular target for future interventions in such conditions.


Subject(s)
Cell Differentiation , Hippocampus/cytology , Neurogenesis/physiology , Neurons/cytology , Stem Cell Niche , Stem Cells/cytology , Transforming Growth Factor beta/metabolism , Animals , Biomarkers/metabolism , Blotting, Western , Cell Proliferation , Cells, Cultured , Cellular Senescence , Doublecortin Protein , Electrophysiology , Female , Gene Expression Profiling , Hippocampus/metabolism , Humans , Mice , Mice, Transgenic , Neurons/metabolism , Oligonucleotide Array Sequence Analysis , RNA, Messenger/genetics , Rats , Rats, Inbred F344 , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Stem Cells/metabolism , Transforming Growth Factor beta/genetics
20.
PLoS One ; 8(12): e66075, 2013.
Article in English | MEDLINE | ID: mdl-24348983

ABSTRACT

Mesozoic marine reptiles and modern marine mammals are often considered ecological analogs, but the extent of their similarity is largely unknown. Particularly important is the presence/absence of deep-diving suction feeders among Mesozoic marine reptiles because this would indicate the establishment of mesopelagic cephalopod and fish communities in the Mesozoic. A recent study suggested that diverse suction feeders, resembling the extant beaked whales, evolved among ichthyosaurs in the Triassic. However, this hypothesis has not been tested quantitatively. We examined four osteological features of jawed vertebrates that are closely linked to the mechanism of suction feeding, namely hyoid corpus ossification/calcification, hyobranchial apparatus robustness, mandibular bluntness, and mandibular pressure concentration index. Measurements were taken from 18 species of Triassic and Early Jurassic ichthyosaurs, including the presumed suction feeders. Statistical comparisons with extant sharks and marine mammals of known diets suggest that ichthyosaurian hyobranchial bones are significantly more slender than in suction-feeding sharks or cetaceans but similar to those of ram-feeding sharks. Most importantly, an ossified hyoid corpus to which hyoid retractor muscles attach is unknown in all but one ichthyosaur, whereas a strong integration of the ossified corpus and cornua of the hyobranchial apparatus has been identified in the literature as an important feature of suction feeders. Also, ichthyosaurian mandibles do not narrow rapidly to allow high suction pressure concentration within the oral cavity, unlike in beaked whales or sperm whales. In conclusion, it is most likely that Triassic and Early Jurassic ichthyosaurs were 'ram-feeders', without any beaked-whale-like suction feeder among them. When combined with the inferred inability for dim-light vision in relevant Triassic ichthyosaurs, the fossil record of ichthyosaurs does not suggest the establishment of modern-style mesopelagic animal communities in the Triassic. This new interpretation matches the fossil record of coleoids, which indicates the absence of soft-bodied deepwater species in the Triassic.


Subject(s)
Feeding Behavior/physiology , Fossils , Reptiles/physiology , Animals , Biological Evolution , Phylogeny , Reptiles/classification
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