Feeding Posture Research Articles

Prevalence of and factors affecting malocclusion in primary dentition among children in Xi'an, China.

BackgroundThis study aimed to investigate the prevalence and associated factors of malocclusion among children with primary dentition in Xi’an, China.MethodsA total of 2,974 subjects were selected from local schools in Xi’an city using a stratified cluster sampling method from January to September 2015. After screening samples according to the inclusion criteria, the final sample size comprised 2,235 pre-school children, with a mean age of 4.82 (SD, 1.76; range, 2.63–6.12) years. Malocclusion traits were assessed by trained clinicians followed by the evaluation of associated factors through clinical examination and a precisely designed questionnaire including data regarding gender, birth place, parental education level, monthly familial income, parental attitude toward the problem of malocclusion, feeding methods of the children, feeding postures, pacifier use, and delivery methods. Data were analyzed using the Chi-square test and logistic regression analysis.ResultsThe most common type of malocclusion was increased overjet (34.99 %) in the sagittal direction, deep overbite (37.58 %), and midline deviation (25.32 %) in the vertical and transverse directions, respectively. The prevalence of posterior crossbite, anterior crossbite, and anterior open bite was 7.56, 6.80 and 6.98 %, respectively. The prevalence of the anterior edge-to-edge occlusion was the lowest (2.46 %). The variables associated with malocclusion (P < 0.05) were birth place (odds ratio [OR] = 1.741 with 95 % CI of 1.384–2.162), insufficient abrasion of primary canines (OR = 1.465; 95 % CI of 1.153–1.894), caries in primary teeth (OR = 2.045; 95 % CI of 1.665–2.539), tongue thrusting (OR = 2.833; 95 % CI of 1.640–3.649), mandibular prognathism (OR = 2.621; 95 % CI of 1.574–3.689), and finger sucking (OR = 1.573 with 95 % CI of 1.098–2.014). The feeding methods (OR = 3.614 with 95 % CI of 3.087–4.596) along with the method of delivery (OR = 1.847 with 95 % CI of 1.323–2.451) have been observed to play an important role in the morbidity of malocclusion (P < 0.05).ConclusionsThe prevalence of malocclusion among pre-school children in Xi’an is higher compared to that in other geographical parts of China. Therefore, early attention to the development of occlusion and necessary interventions toward the associated factors are important to reduce its prevalence and further adverse effects.

Computational Fluid Dynamics Analysis of the Fossil Crinoid Encrinus liliiformis (Echinodermata: Crinoidea).

Crinoids, members of the phylum Echinodermata, are passive suspension feeders and catch plankton without producing an active feeding current. Today, the stalked forms are known only from deep water habitats, where flow conditions are rather constant and feeding velocities relatively low. For feeding, they form a characteristic parabolic filtration fan with their arms recurved backwards into the current. The fossil record, in contrast, provides a large number of stalked crinoids that lived in shallow water settings, with more rapidly changing flow velocities and directions compared to the deep sea habitat of extant crinoids. In addition, some of the fossil representatives were possibly not as flexible as today’s crinoids and for those forms alternative feeding positions were assumed. One of these fossil crinoids is Encrinus liliiformis, which lived during the middle Triassic Muschelkalk in Central Europe. The presented project investigates different feeding postures using Computational Fluid Dynamics to analyze flow patterns forming around the crown of E. liliiformis, including experimental validation by Particle Image Velocimetry. The study comprises the analysis of different flow directions, velocities, as well as crown orientations. Results show that inflow from lateral and oral leads to direct transport of plankton particles into the crown and onto the oral surface. With current coming from the “rear” (aboral) side of the crinoid, the conical opening of the crown produces a backward oriented flow in its wake that transports particles into the crown. The results suggest that a conical feeding position may have been less dependent on stable flow conditions compared to the parabolic filtration fan. It is thus assumed that the conical feeding posture of E. liliiformis was suitable for feeding under dynamically changing flow conditions typical for the shallow marine setting of the Upper Muschelkalk.

Nuchal ligament reconstructions in diplodocid sauropods support horizontal neck feeding postures

Historically, sauropods have been largely perceived as having vertical, ‘S’-curved necks which were hypothesised to allow them to feed from the canopy of trees. Within the past two decades, this popular perception has been questioned, resulting in a debate over neck posture. The osteological differences between sauropods with horizontal neck posture (Diplodocus), and less horizontally inclined necks (Brachiosaurus) suggest differing life and feeding styles. One differing vertebral feature between these polarised bauplans is the bifurcated neural spine. Regardless of the spine condition, sauropods with and without bifurcated spines have been reconstructed exhibiting the same neck posture. Corroborating histology and morphology in extant taxa highlights the presence of modified vertebral ligaments associated with bifurcated spines. Using these extant taxa to better understand the biomechanics of bifurcated spines, this study proposes alternative soft tissue reconstructions. Previous depictions had the bifurcation trough entirely open or harbouring pneumatic diverticula or muscles; conversely this study proposes that the apices of the bifurcated spines were the anchoring points for a split nuchal ligament, and that the trough of bifurcation was predominantly filled with interspinal ligaments. Ligaments provide energy-efficient elastic rebound, and a paired ligament in the cervical series would aid in prolonged, lateral movement in a horizontal plane (i.e. feeding).

Genetics and hybridization in surface and caveAstyanax(Teleostei): a comparison of regressive and constructive traits

Change in ecological conditions, as seen in surface and cave populations of Astyanax (Teleostei), has caused the divergent evolution of a large number of traits like eyes, coloration, taste, lateral line, and different kinds of behaviour like schooling, sleep or feeding posture. Because of the interfertility of surface and cave forms these fish are an exceptional object to study the morphological and genetic basis of the evolution of such complex regressive and constructive traits. Classical crossing analyses and genomic studies are contributing to growing understanding. Both kinds of traits mostly rely on multiple genetic bases and the phenotypic manifestation in the various crosses is similar. The gene effect underlying the phenotypic manifestation may exhibit an exponential increase at differing amounts in the various traits and crosses. Missing or presence of such genetic interaction helps determine whether the variability of eyes or pigmentation exhibited by Astyanax cave fish populations like Micos, is due to a more recent origin or to secondary hybridization with the surface fish. Neither crossing analysis nor QTL mapping revealed that eye reduction is pleiotropically antagonistically related to the increase of taste buds or lateral line sense. Independent inheritance of traits suggests that Astyanax cave fish are subjected to mosaic evolution.

Clinical features of Bednar's aphthae in infants.

PurposeAlthough Bednar's aphthae are common and regress spontaneously, these lesions may lead to feeding intolerance and are often misdiagnosed, rendering examinations useless. This study sheds new light on the clinical features of Bednar's aphthae.MethodsSixteen neonates and infants were newly diagnosed with Bednar's aphthae via routine health check-ups in an outpatient clinic. Medical records were retrospectively reviewed, and the following parameters were analyzed; sex, gestational age, birth weight, mode of delivery, and perinatal problems. A physical examination was carried out during the next outpatient visit to examine the healing process and check for the existence of scars or complications.ResultsInitial presentation included changes in feeding habits (n=10), longer feeding time, reduced intake, and increased irritability. In 6 patients, Bednar's aphthae were discovered incidentally, without prior symptoms. Feeding posture and method of feeding are important causes of Bednar's aphthae. Eleven patients were fed in a horizontal position, whereas 5 patients were fed in a semiseated position. Fifteen patients were bottle-fed, whereas 1 patient was exclusively breastfed. After correcting the feeding position, the ulcerative lesions disappeared within 1 month of diagnosis. During the follow-up period, lesions did not recur in any of the patients.ConclusionThis study suggests that Bednar's aphthae are caused by mechanical pressure. A diagnosis of Bednar's aphthae should be considered when lesions are found on the palate of infants and when symptoms seem to be feeding related. Proper education of parents can both treat Bednar's aphthae and easily prevent its recurrence.

Feeding Postures of Cao Vit Gibbons (Nomascus nasutus) Living in a Low-Canopy Karst Forest

Food acquisition is an important factor in the evolution of primate postural behavior. Gibbons are well known for their ability to exploit terminal branches by means of below branch suspensory feeding, but few studies of gibbon positional behavior have been conducted since the seminal work of the 1970s and 1980s. We studied the feeding posture of three cao vit gibbon groups living in degraded karst forest in Bangliang Gibbon Nature Reserve between August 2008 and December 2009 to determine if body mass, age, and food type affect feeding posture. We found that cao vit gibbons spent most of their time feeding from branches (59.4 %) and twigs (33.2 %) in the middle canopy of the forest (5–10 m). They used suspensory hanging and sitting as their main feeding postures. Large-bodied gibbons spent more time on larger supports than smaller juveniles when feeding on nonfig fruit and leaves. In addition, gibbons of all age–sex classes adopted a suspensory posture more often when using smaller (twigs) or more flexible (lianas) supports. We found little evidence of age–sex differences in the frequency of suspensory feeding. The subtle differences we did detect suggest that intragroup feeding competition or ontogeny may confound the body size effects on feeding posture. Overall our findings conform to the view that within species positional behavior is largely constrained by musculoskeletal anatomy and not by habitat quality because cao vit gibbons showed a similar pattern of canopy and substrate use to gibbons occupying less disturbed forests.

The stalked crinoid fauna (Echinodermata) of the Molucca and Celebes Seas, Indonesia: taxonomic diversity and observations from remotely operated vehicle imagery

The seafloor of the Molucca and Celebes Seas, Indonesia, was investigated using a remotely operated vehicle with high-definition video during 18 dives to depths of 280 to 3200 m. Irregular slopes and rocky substrata supported abundant megabenthos, including stalked crinoids. Video zoomed on many individuals provided enough details to assign 770 stalked crinoids to major taxa and many to species level. These taxa included Guillecrinus neocaledonicus, Ptilocrinus cf. amezianeae, three species of Hyocrinus, an unknown phrynocrinid, Naumachocrinus hawaiiensis, Proisocrinus ruberrimus, Endoxocrinus alternicirrus, seven phenotypes in the Subfamily Metacrininae and one taxon of unknown affiliation. A novel observation of a juvenile Endoxocrinus included the attachment disk to a rocky surface. Taxa usually considered rare were well represented on hard substrata, thus expanding knowledge of their depth distributions. Mostly, stalked crinoids were sparsely distributed in low densities (to 186 individuals per km), except for occasional single-species clusters. Metacrinins and P. cf. amezianeae dominated at depths of 250–600 m, while E. alternicirrus and G. neocaledonicus were the most abundant species at a depth range of 1000–1400 m. The largest peak of species richness (with nine of the 17 taxa identified) occurred at 1000 to 2000 m. Many specimens altered their feeding posture with current intensity, but a balloon-like crown posture is common in low or non-existent currents. The postures of several mobile metacrinin individuals suggest an active role of arms and cirri in slow crawling movements. The possible origin of some taxa from either Gondwanaland or Eurasian margins is discussed using biogeographical and paleontological data. The location of the Wallace line cannot be delimited only using extant stalked crinoid distribution.

Flume studies using 1:1 scale models of Series 2 and basal Series 3 Cambrian gogiid eocrinoids from Guizhou Province, China to determine feeding posture and mode of attachment

In Series 2 and 3 Cambrian of Guizhou Province, China, most echinoderms inhabited deeper/quieter water and were attached directly to siliciclastic substrate or biodetritus by biogluing (extrusion of extensible collagen). Feeding postures of abundant long stalked gogiids (e.g., Sinoeocrinus) from these beds were interpreted to have heeled over in the current from the thin flexible distal end of the stalk, with the brachioles streaming in a loose bundle, down current from the theca. To test these and other feeding posture assumptions, 1:1 scale models (holdfast, stalk, and theca) of three genera were carved from soft rubber and brachioles were modeled from braided fishing line. By varying current velocities long stalked flume models did not significantly heel over. Brachioles, both straight and spiraled, extended vertically from the theca in an (elliptical) cone and distally curved downstream. Disrupted flow around straight brachioles (Sinoeocrinus) kept them somewhat evenly spaced. Spiraled brachioles (Guizhoueocrinus, Globoeocrinus) are initially straight and angle outwards so that each proximal end defines a sector over the theca; this spacing keeps the brachioles free from tangling distally. Biogluing the animal to the bottom or to biodetritus seems to be correctly interpreted from the morphological evidence. Superglue was used as the proxy gluing agent for the models, success was limited. The dewatered, siliciclastic, non-bioturbated, seafloor could be only partly reconstructed and the somewhat viscous glue did not deeply penetrate the illite substrate. It is probable that bioglue had low viscosity, penetrated the sediment easily, and was able to agglutinate a large three dimensional anchoring body of sediment without (as is commonly observed) disrupting bedding.

Active feeding behavior of and current modification by the sea lily Metacrinus rotundus (Echinodermata: Crinoidea)

All modern crinoids, categorized as articulate crinoids, possess muscular articulations in their arms that allow them to maintain their feeding posture in changing current conditions. We tested the responses of the isocrinid Metacrinus rotundus to the introduction of suspended particles in the water column and to the chemical properties of the suspended particles (organic versus inorganic), and measured changes in flow patterns during feeding. The crinoids demonstrated specific behavior in response to organic particles in the current, and chemical extracts consisting of organic matter induced a change in the posture. The currents around the crinoids were disturbed by the crinoid arms only when the particles were passing through the arms, and the current speed and direction were maintained within a certain range. Crinoids are considered to actively form an effective filtration fan in the current, detect if organic matter is present in the current, and control and maintain the current condition to maximize their filter feeding. Living stalked crinoids are restricted to the deep sea, and the abovementioned crinoid strategies are key characteristics for their life in an oligotrophic environment. The development of muscular articulation provides not only a free locomotion but also a sophisticated filter feeding mechanism by acquiring an idealized filtration fan.

Influence of functional head postures on the dynamic functional occlusal parameters.

Background:The dentist utilizes supine position during therapeutic procedures, while the patients assumes extended head posture during mastication. It is critical for the restorative dentist to evaluate and understand the possible effect of change in head posture on occlusal contacts. An understanding of the possible effect will help in better restorative rehabilitation.Aim:The aim of the following study is to evaluate the influence of head postures on the dynamic occlusal parameters.Subjects and Methods:Study group consisted of 50 students from College of Dentistry, King Khalid University. The students were selected randomly from the college student body; they were in the age group of 18-25 years. The head posture evaluated were supine position, upright sitting position and alert feeding position. The head postures were standardized by goniometer and dynamic occlusal contacts were analyzed with Tscan. The data obtained was subjected to statistical analysis with repeated measures of ANOVA to identify the changes in occlusal contacts.Results:The occlusion time was 1.366 (0.484), 1.226 (0.562) and 0.997 (0.429) s for supine, upright and alert feeding position respectively. Disclusion time was for right lateral movement was 0.872 (0.372), 0.629 (0.290) and 0.831 (0.369) s for corresponding head postures. Left lateral disclusion time was 0.621 (0.274), 0.274 (0.345) s for upright and alert feeding posture. Repeated measures of ANOVA showed statistically significant difference between occlusal contacts in different head postures.Conclusion:Within the limitation of the study, it was concluded that there were significant changes in initial occlusal contact, occlusion and disclusion time at all the head postures evaluated in the study.

Substrate use and postural behavior in free‐ranging snub‐nosed monkeys (Rhinopithecus bieti) in Yunnan

Extant colobines represent a predominantly arboreal primate radiation, but there are outliers such as some species of snub-nosed monkeys (Rhinopithecus spp.) that utilize both arboreal and terrestrial substrates. We quantified the degree of terrestriality and the distribution of individuals across canopy levels, the extrinsic and intrinsic determinants and constraints of strata association as well as use of postures in relation to behavior and food sources in a wild population of Yunnan snub-nosed monkeys (Rhinopithecus bieti) in the Samage Forest, China. The subjects spent 80.5% of the observation time in the trees and 19.5% on the ground. Ground use occurred most frequently in the context of travelling (61%) and less often in the context of feeding and resting (30% combined). Adult males frequented the ground significantly more often than other age-sex classes. Age-sex differences were also apparent in substrate preferences, which likely reflect body weight constraints. Adult males were significantly more associated with solid substrates and less with terminal branches than adult females and juveniles. Juveniles were seen more often on unstable ground (i.e. on thin and oblique branches) and in the upper canopy. Substrate use also varied with behavior: feeding was much more common in the upper stratum, outer canopy, on highly inclined and thin branches, as compared to resting. Severe weather also influenced canopy use in that tree crowns were used less often during periods of snowfall. The most frequently exhibited resting and feeding postures was sitting. Standing and suspensory postures were most often used in the context of feeding on lichens.

Convergence in feeding posture occurs through different genetic loci in independently evolved cave populations of Astyanax mexicanus

When an organism colonizes a new environment, it needs to adapt both morphologically and behaviorally to survive and thrive. Although recent progress has been made in understanding the genetic architecture underlying morphological evolution, behavioral evolution is poorly understood. Here, we use the Mexican cavefish, Astyanax mexicanus, to study the genetic basis for convergent evolution of feeding posture. When river-dwelling surface fish became entrapped in the caves, they were confronted with dramatic changes in the availability and type of food source and in their ability to perceive it. In this setting, multiple independent populations of cavefish exhibit an altered feeding posture compared with their ancestral surface forms. We determined that this behavioral change in feeding posture is not due to changes in cranial facial morphology, body depth, or to take advantage of the expansion in the number of taste buds. Quantitative genetic analysis demonstrates that two different cave populations have evolved similar feeding postures through a small number of genetic changes, some of which appear to be distinct. This work indicates that independently evolved populations of cavefish can evolve the same behavioral traits to adapt to similar environmental challenges by modifying different sets of genes.

Double-sided fiber laser beam welding process of T-joints for aluminum aircraft fuselage panels: Filler wire melting behavior, process stability, and their effects on porosity defects

Aluminum alloy T-joints for aircraft fuselage panels were fabricated by double-sided fiber laser beam welding with filler wire, and the influence of the wire feeding posture on the welding process stability was investigated. A CMOS high speed video system was used to observe the wire melting behavior and the weld pool dynamics in real time during the welding process by using a bandpass red laser with an emission wavelength of 808nm as backlight source to illuminate the welding zone. The weld porosity defects were analyzed by X-ray radiography. The effects of wire feeding posture on the wire melting behavior, process stability, and porosity defects were investigated. The experimental results indicated that three distinct filler material transfer modes were identified under different wire feeding positions: liquid bridge transfer mode, droplet transfer mode, and spreading transfer mode. The liquid bridge transfer mode could guarantee a stable welding process, and result in the lowest porosity. Compared with wire feeding in the leading direction, the process was not stable and porosity increased when wire feeding in the trailing direction. Increased in the wire feeding angle was disadvantage for pores to escape from the weld molten pool, meanwhile, it made the welding process window smaller due to increasing the centering precision requirement for adjusting the filler wire.

Postural strategies employed by orangutans (Pongo abelii) during feeding in the terminal branch niche

Obtaining food in an arboreal habitat is complex due to the irregular and flexible nature of the supports available. As the largest predominantly arboreal primate, orangutans are expected to have developed particular postural strategies to enable them to feed successfully. In particular, they need to be able to cope within the terminal branch niche (TBN) as this is where the smallest, most compliant supports are, and also where the majority of the fruit and leaves are situated. We recorded feeding posture, along with a number of ecological and behavioral variables from different age-sex classes to enable analysis of the interactions between these and the compliance of the supports (as estimated from stiffness score). Suspensory postures with a pronograde orientation were used on the most compliant supports for all age-sex classes and appeared to play a particular role in facilitating safe use of the TBN by distributing body weight and using limbs for balance across multiple supports. This contradicts the idea that orthograde suspension evolved in response to the demands of feeding in the TBN. Adult males appear to use the same postures and feeding zones as the other age-sex classes, but appear to use stiffer supports where possible due to their larger body mass. Feeding method differed between the age-sex classes in relation to support stiffness, with larger adult males taking fewer risks due to their larger size, compared to infants and juveniles.

A New Method for Short-Term Rearing of Citrus Psyllids (Hemiptera: Pysllidae) and for Collecting their Honeydew Excretions

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an eco nomically important pest of citrus in the United States, Asia and other parts of the world, as a vec tor of huanglongbing (HLB) or citrus greening, which is considered one of the world's most seri ous diseases of citrus (Gottwald 2010). Addition ally, large populations of ACP can damage plants directly through feeding and excretion activities; ACP feeds on citrus phloem tissues and produces copious amounts of honeydew excretions (Brian sky & Rogers 2007). ACP adults can feed on ma ture citrus leaves, but nymphs must have young tender flush to survive. For biological and patho gen-vector relation studies on ACP (e.g., Wen ninger & Hall 2007; Pelz-Stelinski et al. 2010) rearing of single or small groups of psyllid nymphs or adults on whole citrus plants takes considerable space, time and other resources. Here, we describe a new, simpler method for short-term rearing of ACP using detached mature citrus leaves for adults and detached young ter minal shoots for nymphs (Fig. 1). ACP adults and nymphs were reared singly or in small groups (5-10 per tube) in clear plastic (polypropylene) 50-ml conical centrifuge tubes (3 cm wide and 11.5 cm long; Fisher Scientific, Pitts burg, PA). Young psyllid adults (approximately 1 wk-old) were reared on detached, mature, me dium-size leaves of sweet orange (Citrus sinensis (L.) Osbeck var Ridge Pineapple). Leaf sizes used for adults ranged between 3-4 cm in width and 6-8 cm in length with petioles about 2-3 cm long. The petioles of these leaves were cut diagonally with a sharp razor blade, and each inserted in a small (0.3 or 0.5 mL) microfuge tube filled with water or a piece of moistened cotton wool (Figs. 1A and IE). A piece of Parafilm membrane was wrapped around the top of this tube and the petiole to keep insects from drowning or contact with water. The detached leaf and microfuge tube were then inserted into the rearing tube, and the psyllid adults were added to the latter. The rearing tube was covered with a screw cap that had been finely perforated by a hot needle for ventilation. For better ventilation, how ever, wider holes can be cut in the plastic cap and a piece of fine mesh screen placed under the screw cap to prevent escape of the psyllids. The tubes were kept in an environmental chamber at 25°C and 14 h light per day. The clear plastic wall of the rearing tubes al lowed close observation and photography of the enclosed psyllids during their various activities either by the naked eye or through a stereomicro scope with minimal disturbance (Figs. IB-IE). For example, adults were observed feeding for long periods in their normal feeding posture (Fig. IB) mainly on the midrib or other veins on either side of the detached leaves. They were also observed excreting honeydew droplets regularly (Fig. IE), and occasionally laying eggs (Fig. IB in set), although they normally prefer younger leaves for laying eggs (Brlansky & Rogers 2007). Survival of young adults under the above condi tions on detached mature leaves, that were changed to fresh ones weekly, was 89, 80 and 75% after 2, 3, and 4 weeks, respectively (n = 130 adults). It was later observed, however, that ma ture leaves can stay fresh in the rearing tubes at least for 2 weeks.

Observations on the captive behavior of the rare Patagonian opossum Lestodelphys halli (Thomas, 1921) (Marsupialia, Didelphimorphia, Didelphidae)

We describe the behavior in captivity of the rare Patagonian opossum (Lestodelphys halli) from five individuals captured at three localities, which were kept alive in glass terraria for different periods of time (between 2.5–3.5 months). During our observations we found that L. halli can climb and jump well, has a prehensile tail-tip which can hold the body suspended for several seconds, powerful grasping hind feet and the ability to dig. Feeding preferences of meat (mainly raw) and live animals (i.e., mice, lizards and beetles) over vegetables or fruit was observed. We document the first records of torpor/hibernation for the species, its locomotion and exploration patterns and feeding postures. Resting/sleeping in L. halli is done with the body curled along a vertical axis and its head placed against the chest and between the hind legs, a posture different from previously reported American marsupials. Stereotyped behavior patterns (e.g., grooming) were observed and compared with other studied species, providing comparative information for further studies on New World marsupials.

Flexibility in European starlings’ use of social information: experiments with decoys in different populations

Individuals confronted with novel environments, for instance recently modified environments such as towns or recently occupied habitats such as colonization fronts, have to cope with a lack of information about the location of resources. We hypothesized that, under these conditions, individuals of a social species such as European starlings, Sturnus vulgaris, would be more responsive to social cues indicating food presence than individuals belonging to populations already established in a well-known habitat. To test this hypothesis, we displayed starling decoys with various age, group size and interindividual distance characteristics in feeding postures to evaluate their attractiveness to starlings from towns and colonization fronts and noted whether attracted individuals joined particular decoy groups. Our results supported our hypothesis that sensitivity to social cues varied according to the population’s history, and we suggest that these cues enhance the success of starlings in occupying new habitats.

Near-bottom current direction inferred from comatulid crinoid feeding postures on the Terre Adélie and George V shelf, East Antarctica

For the first time, comatulid crinoid feeding behaviour is used to infer near-bottom current (NBC) directions on the Terre Adélie and George V shelf, East Antarctica. We analysed 47 still-image and video transects sampled during the Collaborative East Antarctic Marine Census (CEAMARC) expedition in 2007–2008. We recorded the inferred current direction from 1537 comatulid observations and interpolated these data across the shelf using the Natural Neighbour Interpolation (NNI) method. Results revealed a mode current directionality at each station and a close local agreement between the observed and interpolated NBC directions. The interpolated NBC directions show a coherent counter-clockwise gyre in the deep George V Basin, with a northward and westward flow over the northern flank of the basin and eastward flow near the coast, consistent with the distribution of bottom salinity. There also appears to be a clockwise gyre on the relatively shallow Adélie Bank, with an easterly or southeasterly flow along the outer-shelf, south and southwesterly on the east Adélie Bank, and westerly along the Terre Adélie coast.

Age-Sex Analysis of Activity Budget, Diet, and Positional Behavior in Alouatta caraya in an Orchard Forest

Howlers (Alouatta spp.) spend more than half of the daytime resting and their diet consists predominantly of leaves. Associated with a general strategy of energy conservation, their positional behavior is characterized by quadrupedalism as the major locomotor mode, and sitting as the most common resting and feeding posture. However, researchers have sparse information on the degree to which age-sex classes fit the generic trends and the influence of habitat structure on them. We compare the activity budget, dietary composition, and positional behavior by age-sex or age classes in a group of black-and-gold howlers (Alouatta caraya) in a small orchard forest. We collected 26,474 behavioral records via instantaneous scan sampling over 1 yr. The main activity was resting (56%) and the diet comprised mainly leaves (82%); sitting was the most adopted feeding (61%) and resting (52%) posture, and walking was the most prevalent locomotor mode (38%). There are age-sex differences for all major behaviors. Whereas resting tended to increase with body size, moving decreased. We observed no difference in the consumption of major plant parts. There were ontogenetic differences in most positional behaviors. Sitting increased from infants to adults during feeding, whereas the opposite occurred for bridging and hanging. During resting, infants curled more and lay less than the other classes did, whereas adults engaged in more sitting. Adults and subadults walked more than individuals of other ages did; infants climbed and bridged more than others did; and, there were opposing trends in leaping and descending. Habitat structure is a partial explanation of the locomotor behavior of black-and-gold howlers.

A modern soft-bottom, shallow-water crinoid fauna (Echinodermata) from the Great Barrier Reef, Australia

A recent preliminary survey revealed that 12 species of unstalked crinoids occur on a gentle sandy slope (12-18 m depth) at Lizard Island, Great Barrier Reef, Australia; five of which are also found on coral reefs. The other seven appear to constitute a unique assemblage restricted to unconsolidated substrates, where most cling to algae or hide beneath rubble or sponges. Members of this assemblage exhibit all of the basic feeding postures found among reef-dwelling species. However, Comatula rotalaria, which lacks anchoring cirri and bears uniquely differentiated short and long arms, exhibits a posture different from other living crinoids. Quantitative transects reveal apparent depth-related differences in species composition: C. rotalaria dominated the 12 transects in 12-13 m (84% of 82 specimens), while Comatella nigra, Comatula cf. purpurea, Amphimetra cf. tessellata and Zygometra microdiscus accounted for 96% of 54 specimens observed along 12 transects in 16-17 m.