Conspicuous Coloration Research Articles

The Conspicuous Colour Blue - ‘Lapis Lazuli’ - In the History of Art

Colour plays a fundamental role in human perception and its effects on cognition and behaviour have intrigued generations of researchers. The intent of this two-part paper is to provide a wider understanding of the history and evolution from its early beginnings. It also analyses the diverse characteristics of plant-based colours and minerals that produce this intriguing colour called, ‘blue’. Although a large amount of research has been conducted in this domain, the psychological processes through which colour operates, have not been explored comprehensively. As a result, the field has observed certain conflicting results. The first part of this article studies the colour ‘blue’ as a pigment. Besides, it also offers some early development of the colour ‘blue’ in the light spectrum set by the initial developments in the history of science. The second part examines how ‘blue’ has long proven a problem for artists. There are a few materials that are blue in their natural state, that can serve as pigments for painters. During the Renaissance period, artists used a pigment called natural ultramarine (Lapis-Lazuli), lauded for its rich and striking appearance to capture the great beyond, this mineral was introduced by Venetian merchants and brought originally from the mines of Afghanistan, located in the remote province of Badakhshan. It is very common when religion, science, and the arts meet to apply philosophies which are interwoven around historical and social events to present science as human, relevant and a lively endeavour. Finally, this paper brings to a conclusion a short briefing of the works of two of the most expressive artists, Giotto and Titian, and the usage of lapis lazuli - (Ultramarine) in the development of their colour palette.

Mammal coloration as a social signal

AbstractOtherwise, apparently cryptic mammals often have conspicuous patches of colour on distal regions of their body, possibly for signalling. To investigate ideas about communication within sociosexual contexts, we used a comparative dataset for 2726 terrestrial mammals to match the coloration and patterning of distal body areas (head, chest, rump and tail) to activity cycle, group size, sexual size dimorphism, mating system and congener overlap at both Class and Order levels. Using phylogenetic controls, we uncovered repeated associations between white colour patches and nocturnality, conspicuous rump patches and sexual selection and multicoloured, complex patterning on distal regions of the body being associated with small group size. Overall, however, we found rather few associations between conspicuous coloration and behavioural, social and morphological variables, suggesting that visual signalling is not a key driver of communication in mammals, perhaps because the majority are nocturnal and solitary, and rely on olfactory signalling.

Foraging predicts the evolution of warning coloration and mimicry in snakes

Warning coloration and Batesian mimicry are classic examples of Darwinian evolution, but empirical evolutionary patterns are often paradoxical. We test whether foraging costs predict the evolution of striking coloration by integrating genetic and ecological data for aposematic and mimetic snakes (Elapidae and Dipsadidae). Our phylogenetic comparison on a total of 432 species demonstrated that dramatic changes in coloration were well predicted by foraging strategy. Multiple tests consistently indicated that warning coloration and conspicuous mimicry were more likely to evolve in species where foraging costs of conspicuous appearance were relaxed by poor vision of their prey, concealed habitat, or nocturnal activity. Reversion to crypsis was also well predicted by ecology for elapids but not for dipsadids. In contrast to a theoretical prediction and general trends, snakes' conspicuous coloration was correlated with secretive ecology, suggesting that a selection regime underlies evolutionary patterns. We also found evidence that mimicry of inconspicuous models (pitvipers) may have evolved in association with foraging demand for crypsis. These findings demonstrate that foraging is an important factor necessary to understand the evolution, persistence, and diversity of warning coloration and mimicry of snakes, highlighting the significance of additional selective factors in solving the warning coloration paradox.

Revision of the genus Robbea (Stilbonematinae: Desmodoridae), worldwide abundant marine nematodes with chromophoric Fe–Br inclusions and the description of a new stilbonematine genus

Abstract Nematodes are one of the most widespread and abundant animal taxa across aquatic and terrestrial environments. In marine shallow-water, porous sediments, members of the subfamily Stilbonematinae may be found in high numbers. Stilbonematinae are characterized by their coat of symbiotic bacteria, which give the nematodes a white appearance, while the nematodes themselves are usually colourless. We identified several species of the genus Robbea (Desmodoridae: Stilbonematinae) in which live specimens had a conspicuous dark purple coloration of the glandular sense organs (GSOs), highly specialized epidermal glands that are prominent in the Stilbonematinae. The dark inclusions in the GSOs of Robbea contained high concentrations of iron and bromide, regardless of their habitat. Morphological and phylogenetic analyses show that the genus Robbea is paraphyletic and we define the new genus Cyathorobbea gen. nov. for species with sucker-shaped post-pharyngeal supplements in males. Furthermore, we describe five new Robbea species from around the world. Some Robbea species are morphologically very similar and required the use of principal component analysis of morphometric data to untangle the diversity in this taxon. Our work emphasizes the value of live animal observations that enable the identification of important characters and highlights the overlooked diversity within the Stilbonematinae.

Deceptive pollinator lures benefit from physical and perceptual proximity to flowers.

Predators often use deception to exploit sensory and cognitive biases in prey. In pollinating insects, these include preferences for conspicuous colours associated with flowers, which predators such as orb-web spiders display as prey lures. Theory predicts that deceptive signal efficacy should covary with both their perceptual similarity and physical proximity to the resources-here, flowers-whose cues they are imitating. Here I used the colour-polymorphic jewelled spider Gasteracantha fornicata to test this prediction. I first examined spiders' capture success in the field, and found their visual resemblance and physical proximity to flowers interacted to mediate capture rates, with colour-similarity becoming increasingly important as the distance between spiders and flowers decreased. I then replicated this interaction experimentally. Spiders adjacent to colour-matched flowers enjoyed heightened capture success relative to those with nearby but colour-mismatched flowers. While spiders with flowers placed at a distance (irrespective of colour) recorded the fewest captures. These results support 'neighbourhood' effects in aggressive deception as receivers' vulnerability to exploitation is mediated by the local signalling community. More generally, they emphasise the importance of the broader information landscape in the ecology of communication, and suggest misinformation is most effective when physically and perceptually proximate to the truth.

Black-and-white pelage as visually protective coloration in colobus monkeys

Conspicuous coloration is often seen as the evolutionary consequence of either sexual selection or warning predators visually about prey defences, although not all conspicuous species fit this paradigm. Exceptions include several species of colobus monkeys whose black-and-white coloration, characteristic of larger colobines, has never been explained. Here, using photographs of black-and-white colobus (Colobus vellerosus) taken in the wild, quantitative image analysis, and vision modelling (acuity-corrected feline, chimpanzee, and raptor vision), we provide evidence that their coloration provides distance-dependent camouflage in natural forest environments. At all viewing distances, black-and-white colobus monkeys blend into their environment because of their high chromatic overlap with the background when viewed by ecologically relevant predator vision models which have low visual acuities. Additionally, for chimpanzee and felid vision, there was evidence of edge disruption at longer viewing distances. Our comparative analyses of different species of colobines do not support an association between black-and-white coloration and larger body mass or group size, but this may simply be due to the limited number of species within the family. We reason that black-and-white colobines gain visually protective coloration through background matching against felids, and also benefit through disruptive coloration against felids and chimpanzees but rely on these protective coloration mechanisms less against raptors.Significance statementConspicuous black-and-white coloration in colobus monkeys has long eluded an evolutionary explanation. Our research, employing photographs of colobus monkeys, image analysis, and vision modelling, unveils a novel approach to this coloration. We show that in their natural forest habitats, black-and-white colobus monkeys employ distance-dependent camouflage against ecologically relevant predators with low visual acuity, blending in with the background at increasing viewing distances. In summary, the evolution of black-and-white colobus coloration appears to be related to background matching against felids, with added benefits of disruptive camouflage against felids and chimpanzees, less so to raptors, offering fresh insights into the complex interplay of coloration and survival strategies in mammals.

Exploring polymorphism in a palatable prey: predation risk and frequency dependence in relation to distinct levels of conspicuousness.

Camouflage and warning signals are different antipredator strategies, which offer an excellent opportunity to study the evolutionary forces acting on prey appearance. Edible prey often escape detection via camouflage, which usually leads to apostatic selection favoring rare morphs. By contrast, defended prey often display conspicuous coloration acting as warning signals to predators, which usually leads to positive frequency dependence and signal uniformity. However, when two morphs of the same species vary greatly in conspicuousness, the maintenance of both cryptic and conspicuous forms in profitable prey populations remains enigmatic. Using the white and melanic morphs of the invasive box tree moth (Cydalima perspectalis) presented at three different frequencies, we investigate (a) the palatability of caterpillars and adult moths to birds, (b) predation rates on the less conspicuous melanic morph, and (c) the role of frequency dependence in balancing morph frequencies. Our results show that caterpillars are distasteful for birds but not adult moths that are fully palatable. We found that the less conspicuous, melanic morph, benefits from reduced predation due to its lower detectability. The more conspicuous, white morph, instead, is more predated and is best off when common, suggesting positive frequency dependence. These results offer new insights into the evolution of color polymorphism and prey defenses in a polymorphic moth species. Further investigation is required to understand the role of different predation regimes on the maintenance of the polymorphism in this species and test whether additional selection pressures operate in natural populations.

Responses of avian predators to the polymorphic harlequin ladybird (Harmonia axyridis)

Abstract The harlequin ladybird (Harmonia axyridis) shows a high level of colour polymorphism. Particular forms differ in their colour combination, pattern and abundance. Two species of wild‐caught passerines native to Central Europe were offered various forms of ladybirds, differing in their colour pattern and abundance in nature. We predicted that those forms that are more abundant in the wild are better protected, as they are more familiar to predators. Forms novemdecimsignata and spectabilis, which represent 97% of individuals in the wild population, significantly differ in their visual appearance (mostly orange vs. mostly black). The form axyridis is very rare in the wild, and suturalis and aninkae do not occur in the wild and were derived from laboratory breedings As predators, we used great tits (Parus major), which are very aversive towards ladybirds, and tree sparrows (Passer montanus), which are quite willing to attack and even eat ladybirds. We compared bird responses to particular ladybird colour forms and included a brown‐painted control to test the effect of conspicuous colours. We showed that both species of birds attacked all conspicuous forms of the ladybird equally and usually very rarely. The brown‐painted novemdecimsignata form was attacked more frequently compared with the conspicuous forms, showing that the visual appearance prevents birds from attacking any conspicuous colour combination. Sparrows tended to eat the attacked ladybirds of forms novemdecimsignata, spectabilis and brown painted. The rare axyridis form and laboratory forms were very well protected from the attack, very likely due to neophobia. We may conclude that despite the outstanding polymorphism of H. axyridis, its protection against avian predators is very effective as long as the red‐and‐black pattern is preserved.

A New Species of the Shrimp Genus Salmoneus Holthuis, 1955 (Malacostraca: Decapoda: Alpheidae) from the Exposed Shores of Eastern and Southern Oman

Salmoneus sultanus sp. nov. is described based on several specimens collected on the exposed shores of Masirah Island and Dhofar, Oman, a region characterised by seasonal upwellings cooling water temperature to less than 23 °C. The new species is compared with the morphologically most similar congeners present in the north-western Indian Ocean, e.g., S. latirostris (Coutière, 1897), S. cristatus (Coutière, 1897), S. serratidigitus (Coutière, 1897), and S. chadwickae Ďuriš and Horká, 2016; the latter species is recorded for the first time from Oman. The conspicuous colour pattern of S. sultanus sp. nov. appears to be diagnostic, differing greatly from that of S. latirostris, S. cristatus, S. serratidigitus, and S. chadwickae.

Co-modulation of structural and pigmentary coloration in Lyropteryx apollonia butterfly.

Nature produces some of the most striking optical effects through the combination of structural and chemical principles to give rise to a wide range of colors. However, creating non-spectral colors that extend beyond the color spectrum is a challenging task, as it requires meeting the requirements of both structural and pigmentary coloration. In this study, we investigate the magenta non-spectral color found in the scales of the ventral spots of the Lyropteryx apollonia butterfly. By employing correlated optical and electron microscopy, as well as pigment extraction techniques, we reveal how this color arises from the co-modulation of pigmentary and structural coloration. Specifically, the angle-dependent blue coloration results from the interference of visible light with chitin-based nanostructures, while the diffused red coloration is generated by an ommochrome pigment. The ability to produce such highly conspicuous non-spectral colors provides insights for the development of hierarchical structures with precise control over their optical response. These structures can be used to create hierarchically-arranged systems with a broadened color palette.

Selection on Visual Opsin Genes in Diurnal Neotropical Frogs and Loss of the SWS2 Opsin in Poison Frogs.

Amphibians are ideal for studying visual system evolution because their biphasic (aquatic and terrestrial) life history and ecological diversity expose them to a broad range of visual conditions. Here, we evaluate signatures of selection on visual opsin genes across Neotropical anurans and focus on three diurnal clades that are well-known for the concurrence of conspicuous colors and chemical defense (i.e., aposematism): poison frogs (Dendrobatidae), Harlequin toads (Bufonidae: Atelopus), and pumpkin toadlets (Brachycephalidae: Brachycephalus). We found evidence of positive selection on 44 amino acid sites in LWS, SWS1, SWS2, and RH1 opsin genes, of which one in LWS and two in RH1 have been previously identified as spectral tuning sites in other vertebrates. Given that anurans have mostly nocturnal habits, the patterns of selection revealed new sites that might be important in spectral tuning for frogs, potentially for adaptation to diurnal habits and for color-based intraspecific communication. Furthermore, we provide evidence that SWS2, normally expressed in rod cells in frogs and some salamanders, has likely been lost in the ancestor of Dendrobatidae, suggesting that under low-light levels, dendrobatids have inferior wavelength discrimination compared to other frogs. This loss might follow the origin of diurnal activity in dendrobatids and could have implications for their behavior. Our analyses show that assessments of opsin diversification in across taxa could expand our understanding of the role of sensory system evolution in ecological adaptation.

Hidden black and yellow thigh color acts as an aposematic signal in the Eastern Gray Treefrog (Hyla versicolor)

AbstractRecognizing form and function of animal defenses is paramount to understanding the ecological and evolutionary forces behind predator and prey dynamics. Color patterns are strongly related to defensive strategies in animals. Some rely on camouflage to avoid detection, while others are brightly colored and conspicuously signal their noxiousness to potential predators. Still others combine cryptic dorsal coloration with colorful patches that are concealed in resting position but are facultatively unveiled by special behavior or simply during activity. Such hidden conspicuous color patches may be an intermediate stage in the evolution from camouflage to aposematism. Many species, especially treefrogs of the family Hylidae, are generally considered to be cryptic, yet show colorful patches on their flanks or thighs and have defensive skin secretions that may have unpalatable properties. We investigated whether the conspicuous black and yellow spotted pattern on the thighs of Eastern Gray Treefrogs (Hyla versicolor) serve as an aposematic signal. We conducted a palatability study to test whether Gray Treefrog skin secretions are unpalatable, and a clay model field study to test whether the conspicuous black and yellow thigh pattern is an aposematic warning coloration that reduces predation. Frog secretions were discriminated against during palatability assays, and clay models painted with a spotted black and yellow pattern suffered lower predation rates. Our findings support the hypothesis that hidden color patches act as aposematic signals in Gray Treefrogs and suggest that more species benefit from aposematic coloration than currently appreciated.

Prevalence and potential evolutionary significance of color variants in freshwater crayfishes (Decapoda: Astacidea)

Abstract Mutations may lead to the evolution and diversification of color phenotypes in animals. Much of the research on this topic, however, has been conducted on vertebrates. I compile here records of color variants in freshwater crayfishes (Decapoda: Astacidea). I found color variants to be surprisingly common, with 115 documented occurrences. The overwhelming majority of these variants were blue-colored (71.3%), although there are records of document red and orange variants, among others. Whether these variants are all due to mutations or can lead to adaptive evolution in crayfishes is unknown. Some crayfish species exhibit conspicuous colors like blue, orange, and red in nature. Many of these conspicuously colored species are also semi-terrestrial burrowers, which have limited migration potential, smaller population sizes, and thus reduced gene flow compared to aquatic burrowing crayfishes. I speculate that in at least some species, conspicuous colors may be a neutral color trait that faces little to no selective pressure. This is one potential explanation as to why semi-terrestrial burrowing species are more likely to be conspicuously colored. Genetic studies and behavioral experiments are required to test this hypothesis.

In paired preference tests, domestic chicks innately choose the colour green over red, and the shape of a frog over a sphere when both stimuli are green

Many animals express unlearned colour preferences that depend on the context in which signals are encountered. These colour biases may have evolved in response to the signalling system to which they relate. For example, many aposematic animals advertise their unprofitability with red warning signals. Predators’ innate biases against these warning colours have been suggested as one of the potential explanations for the initial evolution of aposematism. It is unclear, however, whether unlearned colour preferences reported in a number of species is truly an innate behaviour or whether it is based on prior experience. We tested the spontaneous colour and shape preferences of dark-hatched, unfed, and visually naive domestic chicks (Gallus gallus). In four experiments, we presented chicks with a choice between either red (a colour typically associated with warning patterns) or green (a colour associated with palatable cryptic prey), volume-matched spheres (representing a generalised fruit shape) or frogs (representing an aposematic animal’s shape). Chicks innately preferred green stimuli and avoided red. Chicks also preferred the shape of a frog over a sphere when both stimuli were green. However, no preference for frogs over spheres was present when stimuli were red. Male chicks that experienced a bitter taste of quinine immediately before the preference test showed a higher preference for green frog-shaped stimuli. Our results suggest that newly hatched chicks innately integrate colour and shape cues during decision making, and that this can be augmented by other sensory experiences. Innate and experience-based behaviour could confer a fitness advantage to novel aposematic prey, and favour the initial evolution of conspicuous colouration.

Five new ocellus-bearing species of the cusk-eel genus Neobythites (Ophidiidae, Ophidiiformes) from the West Pacific, with establishment of three new species groups.

Five new West Pacific species of the cusk-eel genus Neobythites (Ophidiidae) from the lower shelf and upper slope of the Solomon Sea, off Okinawa, Japan, and off Fiji are described. The descriptions are based on nine specimens from three fish collections and unvouchered fresh colour photographs showing three specimens taken shortly after being caught. The new species all bear at least one ocellus on the dorsal fin, a conspicuous colour pattern consisting of a dark spot surrounded by a contrasting white or pale ring. Fifteen ocellus-bearing congeners are rather similar with at least one of the new species, requiring detailed comparisons based on a large set of morphometric, meristic, colour and otolith-shape data from over 300 specimens. To facilitate the comparisons among the 20 Neobythites species in total and the preparation of identification keys, three new taxonomic species groups, the australiensis, kenyaensis and longiventralis groups, are established. Also, the steatiticus species group which had been previously established, is slightly updated. A key for identification of each of these four groups is prepared. The most important characters for distinction among groups are the presence and number of preopercular spines, the number and position of ocelli, and pelvic-fin length. For each of the three new groups, species accounts including new species descriptions, within-group comparisons, and identification keys are prepared. For the steatiticus group, only the description of the new species, N. pako n. sp., and an updated account of the Atlantic N. monocellatus are provided, considering previously published accounts of the other seven species in comparisons with those two species and the identification key. The results are shortly discussed, emphasizing the finding of a unique ocellus structure in N. superocellatus n. sp. (australiensis species group) and the need for taxonomic studies of the remaining 10 ocellus-bearing species of Neobythites together with additional, non-ocellus-bearing congeners.

Pupal warning color development in above‐ground pupating species but cryptic color in ground‐surface pupating species of the nine‐spotted diurnal moths (Erebidae: Arctiinae: Syntomini)

AbstractInsects usually have cryptic colors to avoid detection by visually hunting predators. However, if the insects acquire toxic or repellent substances against predators, some of them develop conspicuous coloration to exhibit their unpalatability. Such warning colors allow insects to survive. In the nine‐spotted diurnal moths (Erebidae: Arctiinae: Syntomini), we found the above‐ground pupating species to have conspicuous colored pupae, but the ground‐surface pupating species to have cryptic colored pupae. In this study, the relationships between unpalatability and coloration of these pupae are examined among three species of Amata and one species of Syntomoides. Pupae of the two species (A. germana and A. flava) are conspicuous in their color pattern with seven black dotted lines longitudinally on their pale‐yellow bodies. These pupae are exposed to the aerial predators in a coarse silk mesh hanging from leaves and/or branches. The other two species (A. fortunei and S. imaon) pupate in spaces under stones, fallen twigs and leaves on the ground surface, and the pupae in a coarse silk cocoon is cryptic dark brown. Their pupation site selections are reproduced in the rearing glass vessels. Palatability assessment using lizards as a potential predator suggests that pupae of A. germana, A. flava and A. fortunei are unpalatable and the lizard's feeding response decreases with experience. However, pupae of S. imaon are all eaten (palatable). Finally, the possible evolutionary scenario of pupal colors of these four species is discussed in relation to pupation site selection and palatability.

Self-diagnosing and active protective dual-functional water-borne polyurethane coating based on smart mesoporous containers

In this work, a dual functional coating was constructed to possess self-diagnosing and active anti-corrosion protection using pH-sensitive mesoporous silica containers containing gallic acid (GA). The containers are capable of releasing the inner GA when corrosion occurs at the metal substrate/coating interface due to pH sensitivity. GA can react with the Fe3+ ions to form conspicuous purple color at damaged sites, which provides the coating with a fast and timely corrosion self-diagnosing function. It can also inhibit the expansion of corrosion and realize active corrosion protection. This work provides a new idea for the multifunctional design of smart coatings with a single substance that provides both self-diagnosing and active corrosion protection.

Sphingid caterpillars conspicuous patches do not function as distractive marks or warning against predators.

To avoid predation by visual predators, caterpillars can be cryptic to decrease detectability or aposematic to warn predators of potential unpalatability. However, for some species, it is not clear if conspicuous patches are selected to avoid predation. For example, Pandora sphinx (Eumorpha pandorus, Lepidoptera: Sphingidae) caterpillars are assumed to be palatable and have both cryptic (green, brown) and conspicuous (orange, red) color morphs. Five lateral, off-white to yellow patches on either side may serve as a warning for predators or to draw attention away from the caterpillar's form to function as distractive marks. We conducted a field study in three temperate fragmented forests in Massachusetts to investigate the potential utility of E. pandorus coloration and conspicuous patches. Using four plasticine caterpillar prey model treatments, green and red with and without lateral conspicuous patches, we tested the effects of color, patch patterning, and seasonality on attack rates by a variety of taxa. We found that 43% of the prey models (n = 964) had bite marks by an array of predators including arthropods (67.5%), birds (18.2%), rodents (11.5%), and large mammals (2.8%). Arthropods as dominant predators align with conclusions from previous studies of prey models placed near ground level. Attack rates peaked for arthropods in late August and early September but were more constant across trials for vertebrates. Arthropods, a heterogeneous group, as indicated by the variety of bite marks, showed significantly higher attack rates on green colored prey models and a tendency of higher attack on solid (non-patch patterned) prey models. Vertebrates, more visually oriented predators, had significantly higher attack rates on red colored prey models and patch patterned prey models. Thus, our results did not suggest that conspicuous patch patterning reduced predation and therefore, we did not find support for the distractive mark hypothesis or warning hypothesis. Further, our study shows clear contrasting interpretations by different predators regarding visual defensive strategies.

The genetic basis of conspicuous coloration in the Guadeloupean anole: Evolution by sexual and ecological selection

AbstractUnderstanding how natural selection acts on the genome and contributes to the process of speciation is a primary aim of the study of evolution. Here we used natural variation in two subspecies of the Guadeloupean anole (Anolis marmoratus ssp.), from the island of Guadeloupe in the Lesser Antilles, to explore the genomic basis of adaptation and speciation in Anolis lizards. These subspecies inhabit distinct ecological environments and display marked differences in adult male color and pattern. We sequenced the complete genomes of 20 anoles, 10 from each subspecies, at 1.4× coverage. We used genome‐wide scans of population differentiation, allele frequency spectrum, and linkage disequilibrium to characterize the genomic architecture within and between the subspecies. While most of the genome was undifferentiated, we observed five large divergent regions. Within these regions we identified blocks, 5 kb pairs in length, enriched for fixed single nucleotide polymorphisms. These blocks encompass 97 genes, two of which are candidate pigmentation genes. One is melanophilin (mlph), which helps transport melanosomes within melanocytes. The other is a cluster of differentiation 36 (cd36), which regulates carotenoid pigment sequestration. We used high‐pressure liquid chromatography to confirm that carotenoid pigments are significantly more abundant in the conspicuous orange‐pigmented skin of male A. m. marmoratus suggesting that cd36 may be regulating pigment deposition in this tissue. We identified for the first time a carotenoid gene that is a potential target of divergent sexual selection and may be contributing to the early stages of speciation in Anolis lizards.

A distinctive new species of the coral shrimp genus Microprosthema Stimpson, 1860 from the Atlantic coast of Florida and Honduras (Decapoda: Stenopodidea: Spongicolidae).

A new species of the spongicolid coral shrimp genus Microprosthema Stimpson, 1860 is described on the basis of three specimens collected by hand while scuba diving off the Atlantic coast of southern Florida, with additional photographic records from Roatan, Honduras. Microprosthema dimitrisorum sp. nov. can be separated from all presently known species of the genus by a unique combination of morphological characters, and most easily, by its highly diagnostic and conspicuous colour pattern consisting of large red spots on most of the body and appendages.