Disk Color Research Articles

Rapid and implicit effects of color category on visual search

Many studies suggest that the color category influences visual perception. It is also well known that oculomotor control and visual attention are closely linked. In order to clarify temporal characteristics of color categorization, we investigated eye movements during color visual search. Eight color disks were presented briefly for 20–320 ms, and the subject was instructed to gaze at a target shown prior to the trial. We found that the color category of the target modulated eye movements significantly when the stimulus was displayed for more than 40 ms and the categorization could be completed within 80 ms. With the 20 ms presentation, the search performance was at a chance level, however, the first saccadic latency suggested that the color category had an effect on visual attention. These results suggest that color categorization affects the guidance of visual attention rapidly and implicitly.

In Vivo Imaging of Lamina Cribrosa Pores by Adaptive Optics Scanning Laser Ophthalmoscopy

To visualize and assess the surface-level pores of the lamina cribrosa in patients with glaucoma by using a prototype adaptive optics scanning laser ophthalmoscopy (AOSLO) system. The numbers of laminar pores were compared between color disc photography, scanning laser ophthalmoscopy (SLO) without AO, and AOSLO. The pore area and elongation index were examined for correlation with ocular parameters such as the mean deviation, disc area, cup/disc ratio, disc ovality index, intraocular pressure (IOP), and axial length in the AOSLO images. The 40 eyes (20 normal and 20 glaucomatous) of 40 subjects were enrolled. The AOSLO provided laminar pore images of better quality than other imaging methods, and the number of visible pores was significantly greater in the AOSLO images than in the other imaging methods (the color disc photographs [P < 0.001] and SLO without AO images [P < 0.001]) when compared for 26 subjects. When compared for 40 subjects using AOSLO, the pore area was significantly larger in glaucomatous subjects than in normal subjects (P = 0.031), but elongation index was not. The pore area correlated significantly with the axial length (P = 0.008) in normal subjects, with the untreated IOPs (P = 0.002) in the glaucomatous subjects, and with the axial length (P = 0.001) and cup/disc ratio (P = 0.012) in the total subjects. Via multiple regression analysis, significant correlations with pore area were found for axial length in the normal (β = 0.684, P = 0.001) and total subjects (β = 0.496, P < 0.001) and untreated IOP in the glaucomatous (β = 0.506, P = 0.023) and total subjects (β = 0.331, P = 0.014). AOSLO is a useful imaging technology for assessing laminar pore morphology. The laminar pore area may be affected by axial length and IOP.

Himantura randalli sp. nov., a new whipray (Myliobatoidea: Dasyatidae) from the Persian Gulf

A new whipray, Himantura randalli sp. nov., described from material collected off Bahrain, Kuwait and Qatar, appearsto be endemic to the Persian Gulf. It has been frequently confused with forms of the more widely distributed whiprayHimantura gerrardi Gray and other presently unidentified species from the Indian Ocean. Himantura randalli sp. nov. isdistinguished from these species by a combination of characters, i.e. disc shape, morphometrics, squamation (includingits rapid denticle development and denticle band shape), plain dorsal disc coloration, and whitish saddles on a dark tail inyoung. It is a medium-sized whipray with a maximum confirmed size of 620 mm disc width (DW) and a birth size ofaround 150–170 mm DW. Males mature at approximately 400 mm DW. Himantura randalli sp. nov. is relatively abundantin the shallow, soft-sedimentary habitats of the Persian Gulf from where it is commonly taken as low-value or discarded bycatch of gillnet and trawl fisheries.

THE GRAY NEEDLE: LARGE GRAINS IN THE HD 15115 DEBRIS DISK FROM LBT/PISCES/KsAND LBTI /LMIRcam/L′ ADAPTIVE OPTICS IMAGING

We present diffraction-limited \ks band and \lprime adaptive optics images of the edge-on debris disk around the nearby F2 star HD 15115, obtained with a single 8.4 m primary mirror at the Large Binocular Telescope. At \ks band the disk is detected at signal-to-noise per resolution element (SNRE) \about 3-8 from \about 1-2\fasec 5 (45-113 AU) on the western side, and from \about 1.2-2\fasec 1 (63-90 AU) on the east. At \lprime the disk is detected at SNRE \about 2.5 from \about 1-1\fasec 45 (45-90 AU) on both sides, implying more symmetric disk structure at 3.8 \microns . At both wavelengths the disk has a bow-like shape and is offset from the star to the north by a few AU. A surface brightness asymmetry exists between the two sides of the disk at \ks band, but not at \lprime . The surface brightness at \ks band declines inside 1\asec (\about 45 AU), which may be indicative of a gap in the disk near 1\asec. The \ks - \lprime disk color, after removal of the stellar color, is mostly grey for both sides of the disk. This suggests that scattered light is coming from large dust grains, with 3-10 \microns -sized grains on the east side and 1-10 \microns dust grains on the west. This may suggest that the west side is composed of smaller dust grains than the east side, which would support the interpretation that the disk is being dynamically affected by interactions with the local interstellar medium.

Astrophysically motivated bulge-disc decompositions of Sloan Digital Sky Survey galaxies

We present a set of bulge-disk decompositions for a sample of 71,825 SDSS main-sample galaxies in the redshift range 0.003<z<0.05. We have fit each galaxy with either a de Vaucouleurs ('classical') or an exponential ('pseudo-') bulge and an exponential disk. Two dimensional Sersic fits are performed when the 2-component fits are not statistically significant or when the fits are poor, even in the presence of high signal-to-noise. We study the robustness of our 2-component fits by studying a bright subsample of galaxies and we study the systematics of these fits with decreasing resolution and S/N. Only 30% of our sample have been fit with two-component fits in which both components are non-zero. The g-r and g-i colours of each component for the two-component models are determined using linear templates derived from the r-band model. We attempt a physical classification of types of fits into disk galaxies, pseudo-bulges, classical bulges, and ellipticals. Our classification of galaxies agrees well with previous large B+D decomposed samples. Using our galaxy classifications, we find that Petrosian concentration is a good indicator of B/T, while overall Sersic index is not. Additionally, we find that the majority of green valley galaxies are bulge+disk galaxies. Furthermore, in the transition from green to red B+D galaxies, the total galaxy colour is most strongly correlated with the disk colour.

Scintillating Lustre Induced by Radial Fins

Radial lines of Ehrenstein patterns induce illusory scintillating lustre in gray disks inserted into the central gaps (scintillating-lustre effect). We report a novel variant of this illusion by replacing the radial lines with white and black radial fins. Both white and gray disks inserted into the central gaps were perceived as scintillating, if the ratio of the black/white fin width were balanced (ie, close to 1.0). Thus, the grayness of the central disk is not a prerequisite for the scintillation. However, the scintillation was drastically reduced when the ratio was imbalanced. Furthermore, the optimal ratio depended on the color of the center disks.

前部缺血性视神经病变视盘颜色、视功能及盘周神经纤维厚度的随访分析

前部缺血性视神经病变视盘颜色、视功能及盘周神经纤维厚度的随访分析

Letter to the Editor: Quantitative Analysis of Optic Disc Color

Dear Editor, I read with great interest the article by Kim et al. [1] regarding the use of ImageJ to quantitatively analyze the color of optic discs. The authors proposed three points to measure the intensity per pixel area after grayscale conversion, namely nasal rim (NR), brightest cupping center (BCC), and inferior retinal vein (IRV). They found good inter-observer correlation with this method, along with an age-related decrease of BCC pixel intensity. However, the authors did not mention either the disc area or the characteristics of the subjects enrolled in the study. The optic disc area has a high inter-individual variability: large discs have a larger neuroretinal rim area, an increased total area of lamina cribrosa (LC) pores, and a higher ratio of interpore connective tissue area to total LC area [2]. Therefore, in large discs, it might be difficult to determine a representative region denoting BCC if significant pores of different color are located at the very center of the disc. In small discs, on the contrary, a minimal number of or no cups would make the measurement of BCC inaccurate or impossible. Both Varma et al. [3] and Kashiwagi et al. [4] pointed out there were no age-related differences in disc configuration 3,4. When the proportion of small : normal : large disc sizes in Kim's sample was not constant with age, there was a deviation of disc size in particular age group(s), indirectly reducing the accuracy of the correlation of BCC intensity with age. Also, objective measurements of lens status, color, and opalescence were not performed other than a brief mention of best-corrected visual acuity greater than 20 / 25 in all subjects. In patients suffering from nucleosclerotic cataract, the visual acuity can be much preserved with a disproportionate loss of transparency. Media opacities are likely to be present to some extent in some of the older subjects, which is a major confounding factor. This should prompt the use of a more objective lens assessment system such as Lens Opacity Classification System III or Scheimpflug images to adjust the obtained parameters 5. The ImageJ software enables a particular area of an image to be highlighted and a histogram of intensity to be calculated. Grewal et al. [5] employed this method to study different parts of a nuclear cataract and to determine correlations among several visual functions 5. Its importance, in our context, is highlighted in analyzing optic neuropathies with sectoral pallor, such as ischemic optic neuropathy, 'bow-tie' atrophy from chiasmal compression, and pathological temporal pallor in nutritional optic neuropathy. The contrast of 'intensity' between different areas of a disc might be enhanced in borderline cases, which helps with diagnosis. Serial measurements can serve as a tool to longitudinally monitor patients. Alternatively, the whole neuroretinal rim or cup can be highlighted to provide a more generalized quantitative analysis of the region of interest.

前部缺血性视神经病变视盘颜色、视功能及盘周神经纤维厚度的随访分析&amp;lt;br&amp;gt;The Changes of Optic Disc Color and Visual Function and Peripheral Nerve Fiber Thickness in Patients with Nonarteritic Anterior Ischemic Optic Neuropathy (NAION) in Long-Time Follow Up

目的：追踪观察非动脉炎性前部缺血性视神经病变(NAION)水肿消退期后视盘颜色、中心视力、视野及盘周神经纤维(NFL)厚度变化。方法：对NAION水肿消退后的患者145例147只眼进行视盘颜色、中心视力、视野以及视盘周围NFL厚度的连续观察，按随访时间分组：6~12月内为A组147只眼、12~24月内为B组121只眼、24月以上为C组94只眼，对其结果进行统计分析。结果：NAION视盘色泽全部色淡A组占15.0%、B组16.5%、C组18.1%；三组中心视力分布均无差异(P > 0.05)，视野改变比较有差异(P 0.05)，C 0.05)，颞、上、下象限RNFL厚度均值C Objective: To observe the changes of optic disc color and visural function and peripheral retinalnerve fiber thickness in patients with nonarteritic anterior ischemic optic neuropathy (NAION) in long-time follow up. Methods: 145 cases 147 eyes have diagnosised as NAION at resolving stage, and followed up by visual acuity, visual field (Humphrey), the tomography of disc (Topcon 50EX fundus camera) and TOPCON OCT examination system at diffrernt period of follow up respectively. 6 - 12 months of follow-up 147 eyes as A group, 12 - 24 months 121 eyes as B group , and above 24 monthes 94 eyes as C group (a maximum of 60 months, an average of 34 months). Three stages of the observed results were analyzed. Results: The whole optic disc in pale with A, B, C groups showed 15.0、16.5、18.1 percent respectively. The results in visual acuity showed no significant difference each other (P > 0.05) and there were significant difference in visual field (P < 0.05). Comparion group A to normal control group in mean peripheral RNFl thickness and each quadrant RNFl thickness were statistical significance(P < 0.05); Exception for nasal quadrant, other three quadrants comparison with groups showed that Group C is thinner than Group B, Group B is thinner than Group A. Conclusion: In the long-time follow up after resolving period, the visual field affected NAION changed worse in spite of visual acuity relative stable, and its peripapillary RNFl thickness showed a declining trend.

Spontaneous colour preferences in the Eastern honeybee, Apis cerana

Event Abstract Back to Event Spontaneous colour preferences in the Eastern honeybee, Apis cerana Hema Somanathan1*, Balamurali MG1, Elizabeth Nicholas2 and Natalie H. De Ibarra2 1 Indian Institute of Science Education and Research, School of Biology, India 2 University of Exeter, Psychology, United Kingdom Some insect pollinators in temperate habitats exhibit spontaneous, possibly innate preferences for blueish colours (1-3) despite their ability to quickly learn colours. Here we ask whether this is an adaptation to the colour and reward properties of the local flora (1,4) or whether it is a sensory bias that might be common in pollinating insects. We determined the spontaneous colour preferences in the Eastern honeybee, Apis cerana, that has evolved in tropical habitats, to compare its colour preferences with those of its allopatric sister species in the temperate zone, the Western honeybee (1, 5). These experiments were performed with A.cerana that were free-flying as well as with those that were confined to flight cages for 6 weeks. Marked foragers were individually trained for a short period of time to collect sucrose solution from three rewarded UV-grey discs in various locations on a large black disc. Subsequently they were presented with eight unrewarded colour discs. Foragers that were kept in flight cages for 6 weeks foraging on black feeders preferred blue and violet stimuli. Approaches to yellow, orange and red stimuli were significantly lower. Freely foraging bees had a preference pattern that was shifted towards longer wavelengths which was consistent with the colours of the flowers that prevailed in the surrounding area. The spontaneous preferences found in the Eastern honeybee resembled those of European honeybees and bumblebees. These results support the hypothesis that spontaneous colour preferences in bees arise from a sensory bias which persists despite major differences between floral habitats.

Do disk galaxies with abnormally low mass-to-light ratios exist?

We performed the photometric B, V and R observations of nine disk galaxies that were suspected in having abnormally low total mass-to-light (M/L) ratios for their observed color indices. We use our surface photometry data to analyze the possible reasons for the anomalous M/L. We infer that in most cases this is a result of errors in photometry or rotational velocity, however for some galaxies we cannot exclude the real peculiarities of the galactic stellar population. The comparison of the photometric and dynamical mass estimates in the disk shows that the low M/L values for a given color of disks are probably real for a few our galaxies: NGC 4826 (Sab), NGC 5347 (Sab), and NGC 6814 (Sb). The small number of such galaxies suggests that the stellar initial mass function is indeed universal, and that only a small fraction of galaxies may have a non-typical low-mass star depleted initial mass function. Such galaxies require more careful studies for understanding their star formation history.

Correlations Between Color Gradients and Structural Parameters of Disks in Late-type Spiral Galaxies

From the second group of the data released by the Sloan numerical patrol survey (SDSS DR2), 395 face-on late-type spiral galaxies brighter than 15-th magnitude in the waveband r are selected as the sample. The relations between the color gradients and structural parameters of disks are studied. The results indicate the following: (1) The color gradient is independent of the absolute magnitude (mass) of the disk. (2) The color gradient of disk is concerned with the size of disk. The larger the disk, the steeper the color gradient. (3) The color gradient of disk is concerned with the color of disk. The bluer the disk color, the steeper the gradient. (4) The color gradient of disk is related with the surface brightness of disk. The brighter the disk, the steeper the color gradient. Moreover, the historical constraint formed by the relations between the color gradients of disks and various structural parameters is briefly discussed.

Galaxy Zoo: bar lengths in local disc galaxies★

We present an analysis of bar length measurements of 3150 local galaxies in a volume limited sample of low redshift (z < 0.06) disk galaxies. Barred galaxies were initially selected from the Galaxy Zoo 2 project, and the lengths and widths of the bars were manually drawn by members of the Galaxy Zoo community using a Google Maps interface. Bars were measured independently by different observers, multiple times per galaxy (>=3), and we find that observers were able to reproduce their own bar lengths to 3% and each others' to better than 20%. We find a "color bimodality" in our disk galaxy population with bar length, i.e., longer bars inhabit redder disk galaxies and the bars themselves are redder, and that the bluest galaxies host the smallest galactic bars (< 5 kpc/h). We also find that bar and disk colors are clearly correlated, and for galaxies with small bars, the disk is, on average, redder than the bar colors, while for longer bars the bar then itself is redder, on average, than the disk. We further find that galaxies with a prominent bulge are more likely to host longer bars than those without bulges. We categorise our galaxy populations by how the bar and/or ring are connected to the spiral arms. We find that galaxies whose bars are directly connected to the spiral arms are preferentially bluer and that these galaxies host typically shorter bars. Within the scatter, we find that stronger bars are found in galaxies which host a ring (and only a ring). The bar length and width measurements used herein are made publicly available for others to use (http://data.galaxyzoo.org).

Perceiving Spatial Relations via Attentional Tracking and Shifting

Perceiving which of a scene's objects are adjacent may require selecting them with a limited-capacity attentional process. Previous results support this notion [1-3] but leave open whether the process operates simultaneously on several objects or proceeds one by one. With arrays of colored discs moving together, we first tested the effect of moving the discs faster than the speed limit for following them with attentional selection [4]. At these high speeds, participants could identify which colors were present and determine whether identical arrays were aligned or offset by one disc. They could not, however, apprehend which colors in the arrays were adjacent, indicating that attentional selection is required for this judgment. If selection operates serially to determine which colors are neighbors, then after the color of one disc is identified, attention must shift to the adjacent disc. As a result of the motion, attention might occasionally miss its target and land on the trailing disc. We cued attention to first select one or the other of a pair of discs and found the pattern of errors predicted. Perceiving these spatial relationships evidently requires selecting and processing objects one by one and is only possible at low object speeds.

Potamotrygon tigrina, a new species of freshwater stingray from the upper Amazon basin, closely related to Potamotrygon schroederi Fernandez-Yépez, 1958 (Chondrichthyes: Potamotrygonidae)

A new species of Neotropical freshwater stingray, family Potamotrygonidae, is described from the Río Nanay in the upper Río Amazonas basin of Peru. Potamotrygon tigrina, n. sp., is easily distinguished from all congeners by its conspicuous dorsal disc coloration, composed of bright yellow to orange vermiculations strongly interwoven with a dark-brown to deep-black background. Additional features that in combination diagnose P. tigrina, n. sp., include the presence of a single angular cartilage, low and not closely grouped dorsal tail spines, and coloration of tail composed of relatively wide and alternating bands of creamy white and dark brown to black. Potamotrygon tigrina is closely related to Potamotrygon schroederi Fernandez-Yépez, 1958, which occurs in the Rio Negro (Brazil) and Río Orinoco (Venezuela, Colombia). Both species are very similar in proportions and counts, and share features hypothesized to be derived within Potamotrygonidae, related to their specific angular cartilage morphology, distal tail color, dorsal tail-spine pattern, and ventral lateral-line system. To further substantiate the description of P. tigrina, n. sp., we provide a redescription of P. schroederi based on material from the Rio Negro (Brazil) and Río Orinoco (Venezuela). Specimens from the two basins differ in number of vertebral centra and slightly in size and frequency of rosettes on dorsal disc, distinctions that presently do not warrant their specific separation. Potamotrygon tigrina is frequently commercialized in the international aquarium trade but virtually nothing is known of its biology or conservation status.

Quantitative Analysis of Optic Disc Color

PurposeTo evaluate the reproducibility of ImageJ software in analyzing the color of the optic disc.MethodsOne hundred twelve normal participants (56 males and 56 females) were enrolled in this study. The image of the optic disc was taken using Kowa digital disc photo-graphy, and the gray scales of the nasal rim (NR), brightest cupping center (BCC) and largest inferior retinal vein (IRV) were calculated using histogram in ImageJ. Three different observers calculated the gray scales three separate times. Reproducibility was assessed using the interclass correlation coefficient (ICC).ResultsThe mean age of the participants was 50.6 years old (range, 11 to 82 years). The mean gray scales of the nasal rim were 91.81, 94.91, and 93.24; those of the brightest cupping center were 174.84, 179.94, and 177.76; and those of the largest inferior retinal vein were 61.85, 53.48, and 56.73 for observers 1, 2, and 3, respectively. Inter-observer reproducibility for NR, BCC and IRV was considered good based upon ICC values of 0.944, 0.860, and 0.789 for observers 1, 2, and 3, respectively. Significant age-related differences between the values of the brightest cupping center were noted, and the gray scale score was decreased in the older participants (p < 0.001).ConclusionsThe gray scale of the brightest cupping center diminished with age. ImageJ can be a useful objective tool with high reproducibility in the analysis of optic disc color.

Impairment of color vision in aircraft maintenance workers

The purpose of the study was to examine possible persisting effects to color vision in a group from the Royal Australian Air Force who had exposure to formulations containing neurotoxins during F-111 fuel tank maintenance, relative to two contemporaneous comparison groups. Color vision was tested in 512 exposed personnel, 458 technical-trade comparisons, and 330 non-technical comparisons using the Ishihara test plates and the Lanthony D-15 Desaturated Color disk arrangement test. Participants were excluded if they failed the Ishihara test as this indicates congenital color blindness. From the Lanthony results, the type of color deficient vision (CDV) was diagnosed, and additionally, the Bowman's color confusion index (CCI) was calculated. Regression models were used to examine whether there was an association between color vision deficiencies and F-111 fuel tank maintenance, adjusting for possible confounders. The CCI ranged from 1 to 2.8 (median 1.2, quartiles 1.1, 1.4) in the 2,600 eyes tested. Forty five percent of all participants had blue-yellow CDV in at least one eye. Deficiencies of this nature are caused by environmental exposures. Logistic regression demonstrated statistically significant differences in CCI category in the exposed group versus technical group (odds ratio 1.7: 95% CI 1.3-2.0) and a blue-yellow confusion in the exposed group versus technical group (odds ratio 1.4: 95% CI 1.1-1.7). No differences were observed between the exposed group and the non-technical group. The results indicate reduced color discrimination among the exposed subjects compared to one of two control groups. The findings may be due to previous exposure to solvents among the air force personnel.

Agreement and Accuracy of Non-Expert Ophthalmologists in Assessing Glaucomatous Changes in Serial Stereo Optic Disc Photographs

To compare the interobserver agreement in detecting glaucomatous optic disc changes using serial stereophotography between a large group of non-expert ophthalmologists and glaucoma specialists; to assess the accuracy of non-experts; to investigate whether the interobserver agreement and the accuracy of non-experts changed after a training session. Masked interobserver agreement study. Serial optic disc stereophotos from 40 patients with glaucoma. Three independent experienced glaucoma specialists (readers of the European Glaucoma Prevention Study) evaluated a set of 2 serial optic disc color stereo-slides for glaucomatous change, obtained with a delay varying from 2 to 7 years of 40 patients, masked from the temporal sequence of the slides. Each patient was graded as changed or stable by agreement of 2 of 3 of the experts (the reference standard). Thirty-seven non-expert ophthalmologists independently evaluated the same set of serial optic disc stereo-slides twice, with the second evaluation on the same day, masked from the results of the previous evaluation, after a training session on a separate slide set. Interobserver agreement of non-experts and experts in detecting glaucomatous optic disc changes (expressed as kappa coefficient); agreement of non-experts with the reference standard (accuracy) before and after a training session. The interobserver kappa coefficient (κ) of the non-experts and experts was 0.20 (95% confidence interval [CI], 0.19-0.21) and 0.51 (95% CI, 0.33-0.69), respectively (P<0.0001). The mean κ of the non-experts with the reference standard was 0.33 (95% CI, 0.27-0.39). After a training session, the interobserver agreement of the non-experts increased from 0.20 to 0.27 (95% CI, 0.26-0.28) (P<0.0001). The percentage agreement of the non-experts with the reference standard improved from 68.5% before to 71.4% after the training session (Wilcoxon signed-rank test, P=0.034). The interobserver agreement of non-expert ophthalmologists in detecting glaucomatous optic disc changes using serial stereophotos was significantly lower than that of experts, which was moderate. After a training session, the interobserver agreement and the accuracy of the non-experts showed a small but statistically significant improvement.

Colours of bulges and discs within galaxy clusters and the signature of disc fading on infall

The origins of the bulge and disc components of galaxies are of primary importance to understanding galaxy formation. Here bulge-disc decomposition is performed simultaneously in B- and R-bands for 922 bright galaxies in 8 nearby (z < 0.06) clusters with deep redshift coverage using photometry from the NOAO Fundamental Plane Survey. The total galaxy colours follow a universal colour-magnitude relation (CMR). The discs of L_* galaxies are 0.24 magnitudes bluer in $B-R$ than bulges. Bulges have a significant CMR slope while the CMR slope of discs is flat. Thus the slope of the CMR of the total light is driven primarily (60%) by the bulge-CMR, and to a lesser extent (40%) by the change in the bulge-to-total ratio as a function of magnitude. The colours of the bulge and disc components do not depend on the bulge-to-total ratio, for galaxies with bulge-to-total ratios greater than 0.2. While the colours of the bulge components do not depend significantly on environment, the median colours of discs vary significantly, with discs in the cluster centre redder by 0.10 magnitudes than those at the virial radius. Thus while star formation in bulges appears to be regulated primarily by mass-dependent, and hence presumably internal, processes, that of discs is affected by the cluster environment.

Descriptions of the Tadpoles of Two Poison Frogs, Ameerega parvula and Ameerega bilinguis (Anura: Dendrobatidae) from Ecuador

Tadpoles of two sister species of Ameerega are described. Tadpoles of Ameerega parvula can be distinguished from those of A. bilinguis based on slight differences in their oral disc structure and configuration of the tail fin. Both tadpoles have a tooth row formula 2/3 that is typical for many Ameerega, Epipedobates, and Allobates species. The two species differ in the relative length of the second lower tooth row (P-2). Ameerega parvula tadpoles have a slightly longer P-2 than P-1 row, whereas the P-2 row of A. bilinguis tadpoles is shorter than their P-1. The upper fin at midtail is slightly wider than the lower fin in A. parvula, whereas the lower fin is slightly wider than the upper fin in A. bilinguis tadpoles. Both tadpoles can be discriminated from those of sympatric species based on color and oral disc morphology. However, the oral disc morphology of Ameerega tadpoles provides no synapomorphic characteristics to distinguish Ameerega tadpoles from other dendrobatoid genera.