Food Capture Research Articles

Evaluation of PIQNIQ, a Novel Mobile Application for Capturing Dietary Intake

BackgroundAccurate measurement of dietary intake is vital for providing nutrition interventions and understanding the complex role of diet in health. Traditional dietary assessment methods are very resource intensive and burdensome to participants. Technology may help mitigate these limitations and improve dietary data capture. ObjectiveOur objective was to evaluate the accuracy of a novel mobile application (PIQNIQ) in capturing dietary intake by self-report. Our secondary objective was to assess whether food capture using PIQNIQ was comparable with an interviewer-assisted 24-h recall (24HR). MethodsThis study was a single-center randomized clinical trial enrolling 132 adults aged 18 to 65 y from the general population. Under a provided-food protocol with 3 menus designed to include a variety of foods, participants were randomly assigned to 1 of 3 food capture methods: simultaneous entry using PIQNIQ, photo-assisted recall using PIQNIQ, and 24HR. Primary outcomes were energy and nutrient content (calories, total fat, carbohydrates, protein, added sugars, calcium, dietary fiber, folate, iron, magnesium, potassium, saturated fat, sodium, and vitamins A, C, D, and E) captured by the 3 methods. ResultsThe majority of nutrients reported were within 30% of consumed intake in all 3 food capture methods (n = 129 completers). Reported intake was highly (>30%) overestimated for added sugars in both PIQNIQ groups and underestimated for calcium in the photo-assisted recall group only (P < 0.001 for all). However, in general, both PIQNIQ methods had similar levels of accuracy and were comparable to the 24HR except in their overestimation (>30%) of added sugars and total fat (P < 0.001 for both). ConclusionsOur results suggest that intuitive, technology-based methods of dietary data capture are well suited to modern users and, with proper execution, can provide data that are comparable to data obtained with traditional methods. This trial was registered at clinicaltrials.gov as NCT03578458.

Vortex-induced vibrations: a soft coral feeding strategy?

Abstract

Report on hydrozoans (Cnidaria), excluding Stylasteridae, from the Emperor Seamounts, western North Pacific Ocean.

Fourteen species of hydroids, collected during August 2019 by ROV SuBastian of the Schmidt Ocean Institute, are reported from the Emperor Seamount chain in the western North Pacific Ocean. Two others, Candelabrum sp. and Eudendrium sp., were observed only on videos taken by the ROV. From collections and video observations, eight species of hydroids were found at Jingū Seamount, three at Yomei, Nintoku, and Annei seamounts, and one at Koko Seamount and Hess Rise. At Suiko and Godaigo seamounts, hydroids were seen in videos but they could not be identified. Latebrahydra schulzei, an endobiotic associate of the hexactinellid sponge Walteria flemmingii Schulze, 1886 from Annei Seamount and Hess Rise, is described as a new genus and species tentatively attributed to Hydractiniidae L. Agassiz, 1862. Another new species, Hydractinia galeai, is described from Jingū Seamount. Among its distinctive characters is a zooid termed a sellectozooid, likely serving in both food capture and defence. Hydroids examined from Yomei, Nintoku, and Jingū seamounts are elements of a cold-water fauna occurring in the North Pacific Boreal Bathyal province, while those of Annei and Koko seamounts, and Hess Rise, are part of the biota of the Central North Pacific Bathyal province. Hydroids identified as Bouillonia sp., from Nintoku Seamount, represent the first record of this predominantly deep water tubulariid genus in the North Pacific Ocean. Bonneviella superba Nutting, 1915, from Jingū Seamount, is reported for the first time outside the Aleutian Islands. Bonneviella cf. gracilis Fraser, 1939, known elsewhere only from Dease Strait in the western Canadian Arctic, was also collected on Jingū. In addition to hydroids, medusae of Ptychogastria polaris Allman, 1878 were observed on videos from Nintoku, Jingū, Annei, and Koko seamounts at depths between 2423-1422 m. An unidentified siphonophore was observed near bottom at 2282 m on Nintoku Seamount.

Effects of light cycle on circadian feeding activity and digestive physiology in Haliotis discus hannai

The abalone Haliotis discus hannai is a typical nocturnal animal. It generally feeds and moves at night but evades light by hiding in the shade during the day. However, the effects of different light cycles on the feeding physiology and potential molecular mechanisms responsible for such effects in H. discus hannai have not yet been reported. We examined the feeding patterns of abalones under different light (L)/dark (D) cycles (0 L:24D, 12 L:12D, 24 L:0D) using an infrared camera and analyzed the relationships between circadian digestive enzyme activities, gene expression levels of neuropeptide Y (NPY) and its receptor (NPYR), which can promote appetite, and feeding rhythms. Feeding in abalones, including searching for food and, food capture and intake, was examined by observation of videos. The percentage of abalones feeding under different light/dark cycles had two peaks, at 20:00–22:00 and 02:00–04:00. The ingestion rate was significantly higher in abalones maintained under 12 L:12D compared with 24 L:0D conditions. The percentage of feeding individuals and food intake were significantly lower in the “daytime” compared with at “night” irrespective of the light/dark cycle, suggesting the existence of an independent internal timing mechanism and the possible involvement of circadian clock genes in the regulation of periodic feeding activity in abalones. In abalones maintained under 12 L:12D and 24 L:0D cycles, protease, cellulase, and α-amylase activities started to increase from 18:00, 2 h before the first peak of food intake. Expression levels of NPY peaked at 20:00 and expression levels of NPYR increased again at 04:00, suggesting that NPY and NPYR might be induced before and after the two peak periods of food intake in abalones, respectively. These findings demonstrate the feeding rhythm and ingestion rate of abalones under different light/dark cycles, as well as the relationships among digestive enzyme activities, gene expression levels of NPY and NPYR, and feeding activity, which in turn provides a useful reference for the development of optimal feeding strategies and improved food utilization in abalone aquaculture production.

Regulation of mucosal lectins in the oyster Crassostrea virginica in response to food availability and environmental factors

ABSTRACT Lectins are a large and diverse group of sugar-binding proteins involved in nonself recognition and cell-to-cell interactions. Suspension-feeding bivalves, such as the oyster Crassostrea virginica, are capable of using these molecules to bind cell surface carbohydrates of food particles, allowing particle capture and selection. The aim of this project was to assess whether the expression of mucosal lectins in C. virginica is constant or changes with the season, and to determine whether lectin expression is linked to environmental parameters and/or internal biological factors (gametogenesis). A total of 130 oysters were placed in submerged cages at a tidal estuary and monitored for changes in lectin gene expression over a 1-year period. In parallel, environmental parameters prevailing at the field site, including seawater physicochemical characteristics (temperature, salinity and dissolved oxygen), particulate organic matter and chlorophyll contents, were also monitored. Throughout the study, oysters were dissected and the gills were collected and used for the assessment of the expression of three different lectin genes (CvML, CvML3914 and CvML3912). Remaining tissues were processed for histology and the classification of the gonad development stage. Results showed that when food is abundant, such as during the spring bloom, lectin gene expressions are low, and inversely lectin levels increase with lower food levels. These findings suggest that oysters increase lectin expression to enhance the capture and ingestion of scarce food, while during spring, enough food is already being ingested and lectins are not needed. Furthermore, results showed that as the energy demands of oysters increase (gonad maturation), lectin gene expressions also increase to enhance selective ingestion of nutritious food particles. This study, therefore, demonstrates the seasonality of lectin gene expression in C. virginica, and suggests that lectin regulation is related to the reproduction process and abundance of high-quality food.

Initiation of Posterior Coeloms of an Ophiuroid (Brittle Star) and Plasticity in Their Development.

AbstractIn the ophioplutei of brittle stars, the posterior coeloms are commonly assumed to be produced by a transverse fission of the initially formed coeloms; but in ophioplutei of Ophiopholis aculeata, the posterior coeloms first appear separately as aggregations of mesenchyme-like cells near the base of the posterolateral arms. Initiation of posterior coeloms was similar in ophioplutei of another family and may be similar in diverse ophiuroids. Initiation is easily missed without frequent observations. Early interpretations that diagrammed a fission of the first-formed coeloms appear to have influenced later authors for more than a century. Growth of posterior coeloms from a small initial size facilitated observations of developmental plasticity in growth of coeloms relative to that of larval arms. This plasticity, as observed in echinoplutei of echinoids, is relatively greater growth of a ciliary band for food capture when food is scarce and relatively greater growth of juvenile structures that will function after metamorphosis when food is abundant; however, juvenile structures develop extensively as a rudiment within the echinopluteus prior to settlement and metamorphosis, whereas in ophioplutei there is little development of juvenile structures until metamorphosis. In ophioplutei there is, therefore, less scope for shifting growth to structures that gain function after metamorphosis. Nevertheless, we found that when ophioplutei were at higher concentrations of food, the growth of the posterior coeloms was greater relative to the growth of the larval arms. Developmental plasticity in allocation of growth to larval and postlarval equipment can occur despite disparate patterns of development.

Characterization of the glycans involved in sea urchin Paracentrotus lividus reversible adhesion

Sea urchins have hundreds of specialized adhesive organs, the tube feet, which play a key role in locomotion, substrate attachment and food capture. Tube feet are composed by two functional units: a proximal cylindrical stem that is mobile and flexible, attached to a distal flattened disc that produces adhesive secretions. Oral tube feet discs possess a specialized duo-glandular epidermis that produces adhesive and de-adhesive secretions, enabling strong but reversible adhesion to the substrate. Due to the growing interest in biomimetic adhesives, several studies have been carried out to characterize sea urchin adhesives, and up to date, it has been shown that it is composed by proteins and glycans. The protein fraction has been the subject of several studies, that pin-pointed several adhesion-related candidates. Contrastingly, little is known about the glycans that compose sea urchin adhesives. This study aims at contributing to this topic by focusing on the characterization of the glycosidic fraction of the adhesive secreted by the sea urchin Paracentrotus lividus (Lamarck, 1816), using a battery of 22 lectins, applied to 3 complementary techniques. Our results show that five lectins label exclusively the disc adhesive epidermis and simultaneously the secreted adhesive, being, therefore, most likely relevant for sea urchin adhesion. In addition, it was possible to determine that the glycosidic fraction of the adhesive is composed by a high molecular weight glycoprotein containing N-acetylglucosamine oligomers.

Neural correlates of top-down guidance of attention to food: An fMRI study

We investigated the neural correlates of working memory guided attentional selection of food versus non-food stimuli in young women. Participants were thirty-two women, aged 20.6y (± 0.5) who were presented with a cue (food or non-food item) to hold in working memory. Subsequently, they had to search for a target in a 2-item display where target and distractor stimuli were each flanked by a picture of a food or a non-food item. The behavioural data showed that attention is particularly efficiently drawn to food stimuli when thinking about food. Using fMRI, we found that holding a non-food versus food stimulus in working memory was associated with increased activity in occipital gyrus, fusiform, inferior and superior frontal gyrus. In the posterior cingulum, retrosplenial cortex, a food item that re-appeared in the search array when it was held in memory led to a reduced response, compared to when it did not re-appear. The reverse effect was found for non-food stimuli. The extent of the reappearance effect correlated with the attentional capture of food as measured behaviourally. In conclusion, these results suggest that holding food in mind may bias attention because thinking of food facilitated neuronal responses to sensory input related to food stimuli and because holding food-related information in mind is less taxing on memory.

Revealing enigmatic mucus structures in the deep sea using DeepPIV.

Many animals build complex structures to aid intheir survival, but very feware built exclusively from materialsthat animals create 1,2. In the midwaters of the ocean, mucoid structures are readily secreted by numerous animals, and servemany vital functions3,4. However, little is known about these mucoid structures owing to the challenges of observing them in the deep sea. Among these mucoidforms, the 'houses' of larvaceans are marvels of nature5, and in the ocean twilight zone giant larvaceans secrete and build mucus filtering structures that can reach diameters of more than 1m6. Here we describe in situ laser-imaging technology7 that reconstructsthree-dimensional models of mucus forms. The models provide high-resolution views of giant larvacean houses and elucidate the role thathouse structure hasin food capture and predator avoidance. Now that tools exist to study mucus structures found throughout the ocean, we can shed light onsome of nature's most complex forms.

A Comparative Analysis of the Mouthpart Structures of Two Epischura Species (Copepoda, Calanoida) from Lakes Differing in their Trophic Status

Planktonic copepods, being a connecting link between primary production and higher order consumers, are often a key component of the food net in limnetic ecosystems. Many studies indicate a strong relationship between feeding mode and the structure of the mouthparts of copepods. Early studies attributed members of the genus Epischura to different groups according to their feeding mode and assumed that the species inhabiting the territory of Asia were only adapted to feeding on phytoplankton. We compared the fine morphology of the mouthparts of the Asian species, Epischura baikalensis and E. chankensis, living in different environments. The measurements were made using electron and light microscopy. The mesh sizes of the food capture net formed by the setae and setules ranged between 3.2 μm for E. chankensis and 9.1 μm for E. baikalensis. The area presumably covered by the first maxillae was 13215 μm2 and 66470 μm2, respectively. The resistance force of one seta is ten times higher for E. baikalensis than for E. chankensis. According to the results of calculations of hydrodynamic characteristics based on Reynolds number, these species are unable to filter food particles, but they capture them by drawing them into the mouth. The significant difference in the length of the oral appendages indicates that E. baikalensis is better adapted to living in an oligotrophic lake. For feeding on small particles at low concentrations, it is more beneficial to have long oral appendages even at high energy costs

Mechanics and kinematics of fluid uptake and intraoral transport in the leopard gecko

AbstractDrinking permits amniote vertebrates to compensate for water loss. Lizards (non‐ophidian squamates) use their tongue to imbibe water, but for most lizards the tongue is also employed in other activities. To determine how these various demands can be accommodated alongside the tongue’s role in drinking, it is necessary to firstly determine the tongue’s function in water uptake and intraoral transport in a lizard that does not use this organ for chemoreception or food prehension. We selected the leopard gecko (Eublepharis macularius) for this purpose. We build upon previous morphological observations of the anatomy of its tongue and oral cavity and explore its drinking behaviour through high‐speed cinematography and cineradiography. This allows us to follow the movement of radio‐opaquely labelled water in association with tongue, jaw and throat movements. The tongue is modified to collect water and to release it into the anterior region of the buccal cavity. Repeated tongue cycles are associated with the shifting of the imbibed water into paired ventrolateral chambers and ultimately to its passage to a single, midline posterior chamber prior to swallowing. Tongue movements, capillarity and pressure changes due to hyolingual movements cause water to be moved posteriorly along specific pathways prior to swallowing, bypassing the airways and dorsal surface of the mid‐ and hind tongue. In this licking‐based lingually driven approach to drinking, only small volumes of water can be gathered at a time, with a drinking bout consisting of 20–30 tongue cycles before emersion and swallowing occur. This mechanism differs from drinking in turtles and snakes, which do not employ licking and may take in larger quantities of water. We advance the hypothesis that all lizards have conserved this pattern of tongue‐based water uptake and precisely directed intraoral fluid transport, with specializations for tongue‐based food capture and/or lingually based chemoreception being superimposed thereupon.

Influence of food adhesivity and quantity in lip closing pressure

Lip closing is an important motor act in food acquisition. Appropriate food capture in anticipatory and early oral stages of feeding is essential for mastication and swallowing. The aim of this study was to investigate the effect of food type and quantity on lip closing pressure during food capture with a spoon, and to identify normal lip function during food acquisition in healthy young adults. Twenty young healthy males (age range: 22–30 years) participated in this study. They were asked to eat the test food freely with a spoon. Test foods were yogurt and cream cheese, which were given in quantities of 3, 5 and 10 g in weight; 3 ml water was included as a reference. A strain gauge transducer was embedded in the spoon in advance, and lip closing pressures during food capture were measured and recorded. The Vicon motion analysis system was used to collect three-dimensional kinematic data of spoon operation. Positive pressure with lip closing during capture of adhesive food, such as cream cheese, significantly increased (P < 0.001). Moreover, positive pressure significantly decreased when food quantity increased (P < 0.01), irrespective of food type. Negative pressure that preceded positive pressure appeared more frequently during cream cheese intake and increased when food quantity on the spoon increased (P < 0.001). These findings indicated that participants sucked or squeezed the spoon further during capture of adhesive food. Maximum mouth opening occurred predominantly during the spoon insertion period, while mouth closing occurred predominantly during the spoon withdrawal period. After mouth closing, all subsequent lip pressure events appeared in the withdrawal period. Our results may be useful for comprehending normal lip function during food acquisition in healthy young adults. They may also aid in the diagnosis and management of abnormal lip function in oral hypofunction and dysfunction, which can be examined in future studies.

Digging with ‘hands’: observations of food capture in the flying gurnard Dactylopterus volitans (Linnaeus, 1758)

ABSTRACT Videofilms of a foraging flying gurnard (Dactylopterus volitans) were collected at Itaipu, Niterói, RJ, Brazil. Analysis revealed details of the use of anterior parts of the pectoral fins which act as digging ‘hands’ to access infaunal prey items that are subsequently captured by oral suction feeding. Each pectoral fin has two distinct sections articulated separately on the pectoral girdle. The digging ‘anterior pectoral fin’ mainly consists of segmented and flexible fin rays but has an anterior robust unsegmented ray that provides an edge to the ‘hand’, allowing penetration of the substratum. The huge ‘posterior pectoral fins’ are supported by unsegmented rays. Most digging episodes involved one ‘hand’ and consisted of 1–7 cycles of movement with frequencies 1.15–3.74 cycles s−1. During a cycle, the ‘hand’ is moved forwards and medially above the substratum, then is twisted medially and simultaneously depressed so that the anterior unsegmented ray impacts and enters the substratum. The hand is then drawn backwards and laterally to disturb the substratum. To prevent upward pitching of the head during digging, the ‘posterior pectoral fins’ are both moved anteriorly and laterally to shift the centre of gravity forwards while the caudal and second dorsal fins continue to provide propulsive force.

Polarity in Ciliate Models: From Cilia to Cell Architecture.

Tetrahymena and Paramecium are highly differentiated unicellular organisms with elaborated cortical patterns showing a regular arrangement of hundreds to thousands of basal bodies in longitudinal rows that extend from the anterior to the posterior region of the cell. Thus both ciliates exhibit a permanent antero–posterior axis and left–right asymmetry. This cell polarity is reflected in the direction of the structures nucleated around each basal body such as the ciliary rootlets. Studies in these ciliates showed that basal bodies assemble two types of cilia, the cortical cilia and the cilia of the oral apparatus, a complex structure specialized in food capture. These two cilia types display structural differences at their tip domain. Basal bodies possessing distinct compositions creating specialized landmarks are also present. Cilia might be expected to express and transmit polarities throughout signaling pathways given their recognized role in signal transduction. This review will focus on how local polarities in basal bodies/cilia are regulated and transmitted through cell division in order to maintain the global polarity and shape of these cells and locally constrain the interpretation of signals by different cilia. We will also discuss ciliates as excellent biological models to study development and morphogenetic mechanisms and their relationship with cilia diversity and function in metazoans.

Insights into the diet and feeding behaviour of Red-capped Lark Calandrella cinerea (Aves: Passeriformes: Alaudidae)

Anthropogenic activities have continued to threaten critical habitats of many tropical birds. Few studies, however, have established the habitat requirements, diet and foraging strategies of the threatened species to guide conservation efforts. The Red-capped Lark Calandrella cinerea, which inhabits tropical grasslands in Africa is highly threatened by habitat loss and anthropogenic activities such as burning for pasture regeneration and overgrazing by livestock. Many aspects of the feeding behaviour of this threatened tropical lark are still unknown. We studied the diet and feeding behaviour of the adult Red-capped Lark in its open grassland habitat at Kedong, Naivasha, Kenya from 04 March 2016 to 12 August 2016. Findings revealed that birds predominantly consumed animal nutrients that included insect larvae/caterpillars, grasshoppers, moths/butterflies, ants, and beetles. This was supplemented with plant nutrients (grass seeds) from two grass species, Eragrostis tenuifolia and Harpachne schimperi. Picking and gulping were the most employed food capture and handling techniques respectively. In relation to foraging substrates, grass substrate was most selected for food capture as compared to large mammal dung and soil mounds. Given that tropical grasslands are becoming increasingly threatened biomes, the findings are critical in guiding the management of grassland habitats of birds to ensure their protection from negative impacts as well as deepen understanding on how they adapt to environmental changes.

Structural adequacy of the digestive tract supports dual feeding habit in catfish Pachypterus khavalchor (Siluriformes: Horabagridae)

Lepidophagy is comparatively rare amongst teleost fishes, yet our understanding of this specialization is lacking. Therefore we examined the digestive tract features of Pachypterus khavalchor using morphological, osteological, histological and histochemical techniques to comprehend and relate structural organization of digestive tract with scale eating habit. Morphologically, the alimentary canal is defined by a short and muscular esophagus, well-developed stomach and comparatively short intestine. Gut content analysis and intestinal coefficient value (0.53 ± 0.01) revealed that P. khavalchor exhibit both carnivory and lepidophagy. However, P. khavalchor primarily feeds on the scales (67.47%) and other chitin-rich material like aquatic insects (17.62%), aquatic larvae (8.66%) which affirms its solid association with chitinase producing endosymbionts in the gut. Lepidophagy is further supported by the osteological observations. The perfect segregation of the functions such as food capture, ingestion and processing amongst the different types of teeth located in the oral cavity and pharyngeal region thus could be taken as evolutionary adaptations in scale eaters to support lepidophagy. Specialized arrangement of the esophageal and stomach epithelial folds could be altogether taken as an adaptation with the end goal to frame the scale stacks and accordingly facilitate the handling and processing of chitin-rich bolus. The esophageal mucosa is simple squamous epithelium instead of stratified epithelium with numerous goblet cells to withstand the mechanical harm by hard-food stuff like scales. The cardiac and fundic regions exhibited large number tubular gastric glands with simple columnar epithelium. Surface cells of all three stomach regions stained positive for PAS staining. The intestine is without pyloric caeca and is divided into anterior and posterior region. Histologically it is characterized by simple columnar epithelium with brush border and numerous goblet cells throughout its length. Presence of large number microvilli on anterior and posterior intestine was noticeable. Intestinal goblet cells reacted positively to PAS, AB (pH 1) and AB (pH 2.5). Secretions of goblet cells are important for lubricating and protecting the epithelium. The results of present investigation improve the understanding of the digestive physiology of scale eaters in general and P. khavalchor in particular. Overall, our data indicates that though P. khavalchor predominantly feeds on scale, the digestive physiology is adapted to support dual feeding habit (lepidophagy and carnivory).

A pilot study to understand tooth replacement in near-harvest farmed saltwater crocodiles (Crocodylus porosus): Implications for blemish induction

Saltwater crocodiles (Crocodylus porosus) are farmed in Australia primarily for their belly skin. The desirability and ultimately the value of each skin depends on the extent and location of various industry-defined defects. Anecdotal observations suggest that conspecific interactions are the main contributors with the protrusive 4th dentary teeth (i.e. eye teeth) the most likely cause. It is well known that crocodilians undergo continual tooth replacement, yet no study has investigated tooth replacement rates or tooth growth dynamics in juvenile saltwater crocodiles. In this pilot study, we repeatedly measured eye tooth crown height and observed eye tooth replacement in individually-housed juvenile saltwater crocodiles (n = 98) accounting for 290 individual teeth. The majority of teeth were replaced every three to six months (n = 172) but nine teeth were not replaced over the 15-month study period. After a tooth was lost, the need to replace it quickly was evidenced by a faster tooth growth rate in the first three months (11.07 ± 0.17 mm) but subsequently slowed to a model-adjusted asymptote of 14.03 ± 0.27 mm (p < .001). Interestingly, teeth on the left side of the mandible were, on average, 0.43 ± 0.16 mm shorter than those on the right (p < .001) and, although just outside 5% significance, were replaced 1.20 times as often. Together this is suggestive that crocodiles may preference food capture with the left-hand side of their mouth but requires more structured behavioural observations to confirm. Unusually, the eye-teeth of eight crocodiles did not protrude, which is a normal characteristic of crocodiles compared to alligators, but instead were observed to be growing into the interior of the mouth. This study begins to provide some context to tooth biology when preemptive solutions to tooth-induced blemishes are being sought.

Larval development of Brycon amazonicus (Teleostei, Bryconidae) with a focus on locomotory, respiratory and feeding structures.

In the present work we describe the larval development of Brycon amazonicus, with emphasis on structures linked to swimming, respiration and feeding. We monitored from larval hatching (13 h post-fertilization) to juvenile stage. Formation of the oral cavity and differentiation of gill arches began within 4 h post-hatching (hph) and within 11 hph the primordium of the pectoral fin appeared. At 25 hph, the head was in a rectilinear position with a terminal mouth, when the onset of tooth formation appeared. At 35 hph, gill arches were covered by the operculum and branchiostegal membrane and cusps of teeth pierced the epithelium of the premaxilla and anterior dentary region. Sharp teeth were observed in the maxilla at 171 hph and the pelvic fin primordium appeared at 243 hph, with taste buds on the tongue and the roof of the buccopharyngeal cavity. At 579 hph, all structures related to swimming and food capture were formed. Exogenous feeding of the larvae started at 29 hph, before the endogenous reserves were used up and the development of efficient swimming ability, reflecting the species' need to increasingly specialize on prey capture.

Evolution of the facial musculature in basal ray-finned fishes

BackgroundThe facial musculature is a remarkable anatomical complex involved in vital activities of fishes, such as food capture and gill ventilation. The evolution of the facial muscles is largely unknown in most major fish lineages, such as the Actinopterygii. This megadiverse group includes all ray-finned fishes and comprises approximately half of the living vertebrate species. The Polypteriformes, Acipenseriformes, Lepisosteiformes, Amiiformes, Elopiformes, and Hiodontiformes occupy basal positions in the actinopterygian phylogeny and a comparative study of their facial musculature is crucial for understanding the cranial evolution of bony fishes (Osteichthyes) as a whole.ResultsThe facial musculature of basal actinopterygians is revised, redescribed, and analyzed under an evolutionary perspective. We identified twenty main muscle components ontogenetically and evolutionarily derived from three primordial muscles. Homologies of these components are clarified and serve as basis for the proposition of a standardized and unifying myological terminology for all ray-finned fishes. The evolutionary changes in the facial musculature are optimized on the osteichthyan tree and several new synapomorphies are identified for its largest clades, including the Actinopterygii, Neopterygii, and Teleostei. Myological data alone ambiguously support the monophyly of the Holostei. A newly identified specialization constitutes the first unequivocal morphological synapomorphy for the Elopiformes. The myological survey additionally allowed a reinterpretation of the homologies of ossifications in the upper jaw of acipenseriforms.ConclusionsThe facial musculature proved to be extremely informative for the higher-level phylogeny of bony fishes. These muscles have undergone remarkable changes during the early radiation of ray-finned fishes, with significant implications for the knowledge of the musculoskeletal evolution of both derived actinopterygians and lobe-finned fishes (Sarcopterygii).

When heads are not homologous: the coronae of larval and adult collothecid rotifers (Rotifera: Monogononta: Collothecaceae)

Rotifers are diverse and abundant aquatic micrometazoans that rely on their ciliated apical end (corona) for locomotion and feeding. In order Collothecaceae, which includes mostly sessile species, larval rotifers go through a complex metamorphosis after settlement wherein they replace their corona with an unusual cup-shaped head that functions exclusively in food capture. This new head, called the infundibulum, consists of morphological elaborations such as lobes or tentacles that develop precociously in the larval stage; in adults they function in ambush and sit-and-wait predation. Here, we provide evidence from brightfield and transmission electron microscopy that the infundibulum of collothecid rotifers is derived from the larval foregut and not the larval corona, suggesting that the adult head of collothecids is a morphological novelty and therefore not homologous with the rotifer corona as classically defined. The wide variety of morphologies of the infundibulum suggests that selection to maximize foraging may have driven the evolution of head form in these sessile species, and that future studies of collothecid rotifers should consider the infundibulum as a unique form of food-collection device that is evolutionarily distinct from the rotifer corona.