Ventral Face Research Articles

Trauma of External Genitalia by Firearm: Therapeutic Strategy and Result, about a Case at CHU-YO, Ouagadougou, Burkina Faso

Introduction: Ballistic traumas of the external genitalia are rare especially in civil practice. Emergency surgical exploration is the rule. Case Report: Mr. F.Y., 29 years old, a security agent, admitted to the Urological Emergency Unit of Yalgado Ouedraogo University Hospital of Ouagadougou for trauma of the penile and left purse by firearm. The clinical examination revealed a good hemodynamic status, bladder distension. A suprapubic catheterization was performed. We noted a transfixing and bleeding wound on the penile, and on the left purse which was edematous. The patient was admitted to the operation room 07 hours after trauma. Exploration found a total destruction of the left testicle classified grade 5 of the classification of the American Association of the Surgery of Trauma (AAST). We performed a left orchiectomy. There was a partial rupture of the ventral face of the penile urethra. We performed an end-to-end anastomosis on a Foley catheter CH 18. The Foley catheter was removed after two weeks. Urination was spontaneous without dysuria. Erections were painless and without kinking of penile. Conclusion: Open traumas of the external genitalia are rare and their treatment is an extreme surgical emergency.

A New Species of <I>Valeriana</I> from the Andean Region of Northwestern Argentina Based on Morphological and Molecular Data

Abstract Valeriana serratifolia, a new species from the Andean region of northwestern Argentina, is described and illustrated. It can be distinguished from its closest morphological taxon, V. macrorhiza, by its entire, spathulate leaves with serrulate margin, and falcate fruits, 2–2.5 mm long, crowned by the reduced annular calyx shifted toward the ventral face. A phylogenetic analysis based on DNA sequences of plastid markers trnL-F and trnK intron supported V. macrorhiza as its closest related species. We also provide a key to differentiate V. serratifolia from the epappose species of Valeriana from Argentina.

Métodos de talla y estrategias de reducción en la fabricación de foliáceos en el III milenio A.N.E. [Knapping methods and reduction strategies in leaf-like projectile production in the 3rd millennia B.C.E.

In this paper we present a technological study of leaf-like arrow points recovered in an open-air site from the 3th millennium B.C., named El Tossal de La Munda (Vistabella del Maestrazgo, Castellon). It is located at the central east of Spain, in the southern part of Iberian range in a mountainous area about 100 km far from the coast. The site is on a small flat-topped hill of about 5000 m² and it is 820 m.a.s.l. The upper surface has been strongly eroded and the lithic material has been found directly on the bedrock or over the dissolution clays. We recovered close to 5000 lithic remains, offering an assemblage mainly produced in the 3rd millennia BC: retouched blades and flakes as main groups, leaf-like arrow points, in addition to some other retouched tools as segments (one triangle, one bifacial circle and a trapezoid), scrapers, end-scrapers, denticulate and notches, one raclette and one drill. We also found two small adzes. The cores were intensively exhausted. Just some of them show bladelet scars but most of them are small discoid and irregular shaped cores for the production of small flakes. Few of them show marks of bipolar flaking on anvil. Within the lithic assemblage there is a sample of 73 bifacial rough-outs and projectile points at different reduction stages, from initial blanks to finished and used ones. In addition, we found one refit and one conjoint. All of them are leaf-like arrow points except a fragment showing shoulders as an exception. We have identified some typical accidents in bifacial reduction: fractured rough-outs, overshot flakes, overshot negatives and another accident that we named “bending notches”, linked principally to the pressure technique (two positives and two negatives). We analysed both preforms and finished leaf-like arrow points from a technological point of view, first trying to identify the blank type and shape, and secondly trying to distinguish knapping methods and techniques. We have divided the methods in three main types: parallels (adjacent and contiguous), alternating, and independent method. We have identified the strategies according to edges and blank faces management. In our case, only simple combinations has been detected, mainly alternate (first one face, after the other side on the same edge). We have divided leaf-like production in five technical stages, and we described the identified knapping methods and strategies used at the site according to the reduction stage. In order to show this, we describe in the paper the most significant cases of the site. The identification of blanks has been possible in most of the rough-outs, verifying that the blanks used at the site were irregular and cortical flakes, chunks, fissure slabs and small cores. Despite this, leaf-like production at the site was really homogeneous, applying the same methods and also managing the blank faces similarly. Alternate strategy is completely dominant, firstly removing the ventral face, secondly the dorsal part. The main knapping method used at the site is the independent method, removing consecutively the most highlighted ridges. When the sketch is advanced and reaches a regular shape, the application of parallel method series is common. Technically we have observed two phases: first direct percussion (mainly with stone hammer); second, pressure technique. Heat modifications have been detected in 20 rough-outs and projectiles but most of them seem to be non-intentional, exhibiting cupules and cracks. Most of the finished ones do not show double shine (heat patina). According to this, we state that leaf-like production at the site was not a specialized process but it recovers to use as blanks previously discarded flakes, chunks and exhausted cores, part of them recycled before burning. The elaboration of leaf-like arrow points was embedded in the laminar production, and it played a marginal role within a lithic reduction system that is focused on blade and bladelet production. They used mainly cortical and non-cortical flakes, that seem to be by-products of blade core preparation, or exhausted cores that were reused for this purpose. Despite most of the arrow points result in crude and thick foliated shapes, we argue that in this technological context, the use of waste as blanks constrains the knapping reduction, and lead to rude shapes. Derived from this, we discuss on the leaf-like arrow point morphology and its profitability, the resistance of thick-elliptical tips and their role in the technological framework of the site and its landscape. We also discuss about the visibility of the skilled knapping in this context, when small, irregular and cortical flakes, burned chunks and exhausted cores were used as a blank to make leaf-like projectiles.

Contrasting Specializations for Facial Motion within the Macaque Face-Processing System

Facial motion transmits rich and ethologically vital information, but how the brain interprets this complex signal is poorly understood. Facial form is analyzed by anatomically distinct face patches in the macaque brain, and facial motion activates these patches and surrounding areas. Yet, it is not known whether facial motion is processed by its own distinct and specialized neural machinery, and if so, what that machinery's organization might be. To address these questions, we used fMRI to monitor the brain activity of macaque monkeys while they viewed low- and high-level motion and form stimuli. We found that, beyond classical motion areas and the known face patch system, moving faces recruited a heretofore unrecognized face patch. Although all face patches displayed distinctive selectivity for face motion over object motion, only two face patches preferred naturally moving faces, while three others preferred randomized, rapidly varying sequences of facial form. This functional divide was anatomically specific, segregating dorsal from ventral face patches, thereby revealing a new organizational principle of the macaque face-processing system.

Jam1a-Jam2a interactions regulate haematopoietic stem cell fate through Notch signalling.

SummaryNotch signalling plays a key role in the generation of haematopoietic stem cells (HSCs) during vertebrate development1-3 and requires intimate contact between signal emitting and receiving cells, although little is known regarding when, where, and how these intercellular events occur. We previously reported that the somitic Notch ligands, Dlc and Dld, are essential for HSC specification4. It has remained unclear, however, how these somitic requirements are connected to the later emergence of HSCs from the dorsal aorta (DA). Here we show that Notch signalling establishes HSC fate as their shared vascular precursors migrate across the ventral face of the somite and that Junctional adhesion molecules (JAMs) mediate this required Notch signal transduction. HSC precursors express jam1a and migrate axially across the ventral somite, where Jam2a and Notch ligands Dlc and Dld are expressed. Despite no alteration in the expression of Notch ligand or receptor genes, loss of function of jam1a led to loss of Notch signalling and loss of HSCs. Enforced activation of Notch in shared vascular precursors rescued HSCs in jam1a or jam2a deficient embryos. Together, these results indicate that Jam1a – Jam2a interactions facilitate the transduction of requisite Notch signals from the somite to the precursors of HSCs, and that these events occur well before formation of the DA.

Morphological and mechanical characterisation of the hindwing nodus from the Libellulidae family of dragonfly (Indonesia)

In this communication, the morphologies and mechanical characteristics of nodi from the hindwings of seven Indonesian Libellulidae dragonfly species are identified. Geometrical analyses reveal that in all species, the shape of dorsal face resilin is relatively long and thin while ventral face resilin covers a greater surface area than dorsal face resilin, and is shaped like a hook. Finite element analyses reveal that the magnitude of strain energy may differ considerably between species, even though the locations of highest strain energy are usually the same. Importantly, a correlation is found to exist between the mechanical forces that build up in the resilin, the face under investigation (dorsal or ventral) and the elongational shape factor of the resilin.

Phylogeny of the Poorly Known Ciliates, Microthoracida, a Systematically Confused Taxon (Ciliophora), with Morphological Reports of Three Species

Three species of Microthoracids, Lopezoterenia paratorpens n. sp., Trochiliopsis australis Foissner et al., 1988 and Discotricha papillifera Tuffrau, 1954, collected from Chinese coastal waters, were investigated using live observation and protargol staining methods. Lopezoterenia paratorpens n. sp. was characterized by its squarely shaped cortical papillae and by dorsal kineties which contained loosely distributed basal bodies. Trochiliopsis australis was revealed to have two oral membranelles, which was not recorded in the original report. Phylogenetic analyses were carried out based on SSU rRNA gene sequence data from each of the three species, and on other available data for microthoracids. The results showed that the order Microthoracida is not monophyletic because the family Discotrichidae, which contains L. paratorpens and D. papillifera, forms a clade separated from the "core" Microthoracids clade. The topologies of the maximum likelihood and Bayesian inference trees, along with the distinct morphological characteristics found previously, suggest that the family Discotrichidae should not be assigned to the order Microthoracida. We propose to designate a new order, Discotrichida n. ord. which diagnosed as: flattened ciliates with conspicuous cortical papillae on both dorsal and ventral faces, rod-shaped mucocysts, and an asymmetric cytopharyngeal basket. Also, the fact that Leptopharynx clusters with the assemblage including T. australis, and Pseudomicrothorax is located distantly from Leptopharynx indicates that the classification of Pseudomicrothoracidae and Microthoracidae by Foissner (1985) is justified.

Caryopsis micromorphological survey of the genus Themeda (Poaceae) and allied spathaceous genera in the Andropogoneae

A caryopsis micromorphological survey of 15 species of the genus Themeda Forssk. (Poaceae) and 4 species of allied spathaceous genera in tribe Andropogoneae allowed the recognition of 2 types of caryopses based on the ventral face and embryo shape for the first time. One kind of caryopsis had a concave ventral face with a grooved embryo, and the other kind of caryopsis had a flat ventral face with a keel-shaped embryo. Although the ventral face and embryo shapes had limited taxonomic value at the infrageneric level, the caryopsis shapes, embryo proportion, and sculpturing patterns were found to be valuable taxonomic characters at the interspecific level in Themeda . Consistent micromorphological characters of style base persistence and dorsiventral compression were observed for the first time in the caryopses of representative species of spathaceous genera in the Andropogoneae.

Studies in the liverwort family Metzgeriaceae (Metzgeriales) from southern Africa. 1. Metzgeria nudifrons Stephani and a key to the species

AbstractThis is the first of several projected articles on the taxonomy of southern African Metzgeriaceae H. Klinggr. A brief history of the genus Metzgeria Raddi in southern Africa, the only local representative, is presented. Family and genus descriptions, as well as a key to the species, are provided. Of the seven species currently recognized in southern Africa, M. nudifrons is the only species with gemmae on the dorsal surface of the thallus. It is also characterized by the distinctly broad costa, hairy male branchlets as well as single and straight hairs on the ventral face and margins of the thallus. Metzgeria nudifrons is described, illustrated and its geographical distribution mapped.

Phylogeny of the Poorly Known Ciliates, Microthoracida, a Systematically Confused Taxon (Ciliophora),with Morphological Reports of Three Species.

Three species of Microthoracids, Lopezoterenia paratorpens n. sp., Trochiliopsis australis Foissner etal., 1988 and Discotricha papillifera Tuffrau, 1954, collected from Chinese coastal waters, were investigated using live observation and protargol staining methods. Lopezoterenia paratorpens n. sp. was characterized by its squarely shaped cortical papillae and by dorsal kineties which contained loosely distributed basal bodies. Trochiliopsis australis was revealed to have two oral membranelles, which was not recorded in the original report. Phylogenetic analyses were carried out based on SSU rRNA gene sequence data from each of the three species, and on other available data for microthoracids. The results showed that the order Microthoracida is not monophyletic because the family Discotrichidae, which contains L. paratorpens and D. papillifera, forms a clade separated from the "core" Microthoracids clade. The topologies of the ML and BI trees, along with the distinct morphological characteristics found previously, suggest that the family Discotrichidae should not be assigned to the order Microthoracida. We propose to designate a new order, Discotrichida n. ord. which diagnosed as: flattened ciliates with conspicuous cortical papillae on both dorsal and ventral faces, rod-shaped mucocysts, and an asymmetric cytopharyngeal basket. Also, the fact that Leptopharynx clusters with the assemblage including T. australis, and Pseudomicrothorax is located distantly from Leptopharynx indicates that the classification of Pseudomicrothoracidae and Microthoracidae by Foissner (1985) is justified. This article is protected by copyright. All rights reserved.

Top-Down Control of Visual Responses to Fear by the Amygdala

The visual cortex is sensitive to emotional stimuli. This sensitivity is typically assumed to arise when amygdala modulates visual cortex via backwards connections. Using human fMRI, we compared dynamic causal connectivity models of sensitivity with fearful faces. This model comparison tested whether amygdala modulates distinct cortical areas, depending on dynamic or static face presentation. The ventral temporal fusiform face area showed sensitivity to fearful expressions in static faces. However, for dynamic faces, we found fear sensitivity in dorsal motion-sensitive areas within hMT+/V5 and superior temporal sulcus. The model with the greatest evidence included connections modulated by dynamic and static fear from amygdala to dorsal and ventral temporal areas, respectively. According to this functional architecture, amygdala could enhance encoding of fearful expression movements from video and the form of fearful expressions from static images. The amygdala may therefore optimize visual encoding of socially charged and salient information.

Scale morphology of Prochilodus lineatus with emphasis on the scale epithelium

The fish body is entirely covered by a thin, smooth and glandular epidermis, closely attached to the scales inserted on the dermis. The descriptive work on this tissue dates to twenty or thirty years ago, bears very little photographic record and does not focus on the scale epithelium, despite the fact that it is in direct contact with the environment. Thereupon, the present study characterizes the scale epithelium of Prochilodus lineatus, a robust species of fish. The observations show that the scale is completely covered by epithelium thicker on the proximal end of the scale, multilayered on the dorsal surface and undifferentiated on the ventral surface, and covered by mucous producing cells, mostly acid mucous. The scale is formed by plywood-like collagen matrix of collagen type III and supported by a network of elastic fibers on the ventral face. Differentiated cellular types are present, such as club cells, considered to be responsible for the release of alarm substances, which suggests possible use in environmental assessment as a non-invasive technique.

Whole or sectioned otoliths? Choosing the best method for aging bluemouth, Helicolenus dactyloterus (Delaroche, 1809)

Several studies on bluemouth age and growth have been published over the last two decades, but they show inconsistent differences in maximum age estimates, suggesting interpretation differences in reading whole or sectioned otoliths. In order to clarify this issue, the present study was carried out to assess bias and precision of age reading between three age readers using three aging procedures (the ventral face of sectioned otoliths, the ventral face of whole otoliths, and the posterior region of whole otoliths) in the same individuals of the same statistical sample covering a wide total body length range (10–44cm). Good precision between – reader comparisons and aging procedures was detected with coefficients of variation and average percent errors below 6.70% and 4.17%, respectively. The lowest total agreement between readers was obtained for the ventral face of sectioned otoliths (40.00%) and the highest for the posterior region of whole otoliths (64.17%) increasing to 83.48% and 88.33%, respectively, within ±1 year. The percentage of agreement within ±1 year between aging methodologies was above 90%. No systematic disagreement between readers was detected (p>0.05) as also no significant differences between readers (U, p>0.82) and aging procedures (U, p overall=0.92, p by 5cm length class >0.55). The results of this study indicate that both sectioned and whole otoliths can be used for aging bluemouth across its length range.

Mucoid cyst of the penis: Case report and literature review

Penile cysts are uncommon lesions. In general, they are asymptomatic and do not interfere with sexual function. Most of them are present since birth, but usually they are only detectable in adolescence or adulthood. We report a rare case of a young adult man with a 5 × 5-cm nodule on the prepuce (ventral face), which appeared 2 years ago and interfered with his sexual function. The nodule was excised by circumcision and a histopathologic study was performed. Histopathologic examination revealed a mucoid cyst of penis with epidermoid metaplasia. No recurrence was observed at a 6 months follow-up and the patient's sexual function returned to normal.

Thoracic and heart biometrics of non-anesthetized agouti (Dasyprocta primnolopha Wagler, 1831) measured on radiographic images

The agouti is a species intensively hunted throughout the Amazon and the semi-arid regions of northeastern Brazil. Considering the current trend in conservation management of wild species, the aim of this study was to determine the morphometric reference to the heart of agouti raised in captivity, based on thoracic and cardiac measurements in these animals. Thirty adult agoutis, 1 to 3 years of age, without clinical signs of cardiac disease were selected. The animals were physically restrained and radiographies in laterolateral (LL) and ventrodorsal (VD) recumbence were produced. The following measures were taken: the apicobasilar length of the heart (at the most cranial height of the Carina region to the heart apex) (AB), maximum width of the heart perpendicular to AB (CD), heart inclination angle (AIC), trachea inclination angle (AIT), distance from the right heart wall (DPTd), distance from the left heart wall (DPTe) and vertical depth of the thorax, and the ventral face of the vertebral column to the dorsal border of the sternum at the level of the trachea bifurcation (H). The ratios between AB/CD, AB/H and CD/H were also analyzed. To calculate the vertebral heart scale (VHS), the AB and CD measurements were laid over the thoracic vertebra starting at T4. Radiographic evaluation showed values consistent with those reported in small animals and some wild and exotic species. The main biometric values in the chest cavity and heart of agouti are arranged as follows: (1) The ratios between AB/H ratio and CD/H were not sensitive for identifying heart increases (p>0.05), while the ratio AB/CD was more sensitive in this identification (p<0.05); (2) AIC: 21.2±6.4º (mean between male and famale); (3) AIT for males and females: 9.93±3.23° and 8.4±3.94°; (4) DPTd and DPTe for males: 0.97±0.40cm and 0.7±0.30cm; (5) DPTd and DPTe for females: 1.12±0.42cm and 01.02±0.43cm; (6) VHS for males and females: 7.75±0.48v e 7.61±0.34v; (7) The caudal vena cava (CVC) was visualized dorsal-cranially and located right of the midline. The data obtained allowed the acquisition of the first reference values for biometry of the heart of agoutis, contributing to better understanding of cardiac morphology and identification of cardiomyopathy in these animals.

Further observations on the Jurassic dinoflagellate cyst Gonyaulacysta dentata (Raynaud 1978) Lentin & Vozzhennikova 1990 emended Riding 2012

Gonyaulacysta dentata is a large and morphologically distinctive dinoflagellate cyst. It is confined to the Late Callovian to earliest Oxfordian (Peltoceras athleta to Quenstedtoceras mariae zones) interval of the Boreal Realm and the Subboreal Province in the northern hemisphere, and has therefore been interpreted as a cold water species. The holotype of G. dentata is from the Staffin Shale Formation of Staffin Bay, Isle of Skye, northwest Scotland and has been lost. Consequently another well-preserved specimen from the Staffin Shale Formation of the Isle of Skye is proposed as a neotype. The ventral and apical areas of G. dentata are characterised by discontinuous, low, smooth sutural ridges. However, the 5″/6″, 4′/6″ and 4′/1′ sutures on the ventral side of the epicyst are frequently indicated by relatively high denticulate crests. The 2″′/1p suture and the cingular sutures may also be developed on the ventral face. Conversely, the dorsal and lateral sutural crests, except in the apical area, are prominent and denticulate. G. dentata is present in East Greenland. Two specimens were recorded, as Gonyaulacysta eisenackii subsp. oligodentata, from the Late Callovian of Jameson Land. These are probably from the Olympen Formation, and not the Upper Vardekløft Formation as was originally stated. This occurrence is entirely consistent with the Boreal distribution of G. dentata. The range of G. dentata, the Callovian–Oxfordian transition, was characterised by significantly lowered palaeotemperatures. Several other dinoflagellate cyst species are also believed to be cold water taxa, and migrated south from the Boreal Realm into Europe at this time.

URGORRI COMPLANATUS GEN. ET SP. NOV. (CRYPTOPHYCEAE), A RED-TIDE-FORMING SPECIES IN BRACKISH WATERS(1).

The morphology, ultrastructure, phylogeny, and ecology of a new red-tide-forming cryptomonad, Urgorri complanatus Laza-Martínez gen. et sp. nov., is described. U. complanatus has been collected in southwestern European estuaries, blooming in the inner reaches of several of them. The estuarine character of the species is also supported by its in vitro salinity preferences, showing a maximum growth rate at 10 psu. U. complanatus is a distinctive species and can be easily distinguished by LM from other known brackish and marine species. Cells are dorsoventrally flattened. The plastid has two anterior lobes. One pyrenoid is located in each of the lobes, and a third one on the posterior part. Thylakoids are arranged in pairs and do not penetrate pyrenoids. The plastid is reddish due to the presence of the phycoerythrin Cr-PE545. An orange discoidal eyespot lies beneath the nucleus, in the posterior ventral face of the plastid. A long furrow runs from the vestibulum, and a gullet is lacking. The periplast is composed of an inner sheet. The nuclear 18S rDNA based molecular analysis reveals U. complanatus is not related to any of the main cryptomonad lineages. Based on ultrastructural and pigment data, the most probable relatives are those merged under the family Geminigeraceae. Its lack of derived characters, together with the presence of characters proposed in previous studies to be primitive, suggests Urgorri could be considered representative of the cryptophycean ancestral character state.

Two New Shrubby Species of the Genus Staelia (Rubiaceae) from Serra do Curral Frio, Bahia, Brazil

Abstract Two new shrubby species of Stadia (Rubiaceae) from northeastern Brazil are described and illustrated. Staelia glandulosa inhabits rocky fields on white sand areas, and differs from S. virgata in its shrubby habit, entirely glandular stipular bristles, large flowers, number of calyx lobes and large seeds. Staelia harleyi was found in the Cerrado biome on sandstone rocks at altitudes of 1,000 m, recognizably different from S. virgata because the plant is shrubby, its calyx is a conspicuous tube, the calyx lobe is longer than the corolla tube, the corolla lobes are internally pilose, the ventral face of seeds has transverse furrows and the bracteole is sagittate at the apex. Electron microphotographs of the fruit and seed and images of both species in their habitats are provided.

Face Processing Changes in Normal Aging Revealed by fMRI Adaptation

We investigated the neural correlates of facial processing changes in healthy aging using fMRI and an adaptation paradigm. In the scanner, participants were successively presented with faces that varied in identity, viewpoint, both, or neither and performed a head size detection task independent of identity or viewpoint. In right fusiform face area (FFA), older adults failed to show adaptation to the same face repeatedly presented in the same view, which elicited the most adaptation in young adults. We also performed a multivariate analysis to examine correlations between whole-brain activation patterns and behavioral performance in a face-matching task tested outside the scanner. Despite poor neural adaptation in right FFA, high-performing older adults engaged the same face-processing network as high-performing young adults across conditions, except the one presenting a same facial identity across different viewpoints. Low-performing older adults used this network to a lesser extent. Additionally, high-performing older adults uniquely recruited a set of areas related to better performance across all conditions, indicating age-specific involvement of this added network. This network did not include the core ventral face-processing areas but involved the left inferior occipital gyrus, frontal, and parietal regions. Although our adaptation results show that the neuronal representations of the core face-preferring areas become less selective with age, our multivariate analysis indicates that older adults utilize a distinct network of regions associated with better face matching performance, suggesting that engaging this network may compensate for deficiencies in ventral face processing regions.

Functional morphology of the luminescence system of Siphamia versicolor (Perciformes: Apogonidae), a bacterially luminous coral reef fish

Previous studies of the luminescence system of Siphamia versicolor (Perciformes: Apogonidae) identified a ventral light organ, reflector, lens, duct, and a ventral diffuser extending from the throat to the caudal peduncle. The control and function of luminescence in this and other species of Siphamia, however, have not been defined. Morphological examination of fresh and preserved specimens identified additional components of the luminescence system involved in control and ventral emission of luminescence, including a retractable shutter over the ventral face of the light organ, contiguity of the ventral diffuser from the caudal peduncle to near the chin, and transparency of the bones and other tissues of the lower jaw. The shutter halves retract laterally, allowing the ventral release of light, and relax medially, blocking ventral light emission; topical application of norepinephrine to the exposed light organ resulted in retraction of the shutter halves, which suggests that operation of the shutter is under neuromuscular control. The extension of the diffuser to near the chin and transparency of the lower jaw allow a uniform emission of luminescence over the entire ventrum of the fish. The live aquarium-held fish were found to readily and consistently display ventral luminescence. At twilight, the fish left the protective association with their longspine sea urchin, Diadema setosum, and began to emit ventral luminescence and to feed on zooplankton. Ventral luminescence illuminated a zone below and around the fish, which typically swam close to the substrate. Shortly after complete darkness, the fish stopped feeding and emitting luminescence. These observations suggest that S. versicolor uses ventral luminescence to attract and feed on zooplankton from the reef benthos at twilight. Ventral luminescence may allow S. versicolor to exploit for feeding the gap at twilight in the presence of potential predators as the reef transitions from diurnally active to nocturnally active organisms.