Body Color Research Articles

Charismatic Species and Birdwatching: Advanced Birders Prefer Small, Shy, Dull, and Rare Species

ABSTRACT Studies about charismatic bird species have been carried out using the general public; among the most common charismatic attributes are body mass and coloration. However, research on birders as a target population is lacking. Birders are people who identify bird species based on visual or acoustic cues. It is important to study this group directly because they invest a lot of time and effort in citizen science projects and donate money to the conservation of nature. Identifying charismatic species for birders can help to determine the optimal flagship species for this group. Because some studies show that preferences for certain species and their attributes may be dependent on the personal characteristics of the respondents, we decided to study the preferences of different types of birder (casual, intermediate, advanced). We surveyed 2,303 German birders and found advanced birders to prefer species with a lower body mass and less coloration/brightness, compared with casual and intermediate birders. Moreover, advanced birders prefer species that are difficult to detect: that is, nocturnal species, species with larger flight distances, species with smaller population sizes, and nonurban birds. Because birders differ from the public in species preferences, this should be taken into account when species are chosen for conservation purposes, initiating citizen science projects, or management plans.

Display Responses of Galápagos Lava Lizards ( Microlophus bivittatus) to Manipulation of Male Shoulder Epaulets on Conspecific-Mimicking Robots

Many animal taxa perform stereotyped displays during ritualized contests over territory and mates. Such displays facilitate assessment of an opponent's prowess and reduce the probability of physical injury. Color patterns likewise can serve as indicators of an individual's body condition. Male San Cristóbal Lava Lizards (Microlophus bivittatus) of the Galápagos Islands possess a black epaulet on each shoulder that contrasts with their surrounding body coloration. We created robots with the appearance of conspecific males to explore the potential function(s) of the epaulets in a series of four experiments. Our experiments focused on epaulet presence/absence, body location, and location relative to the axis of body motion (pectoral versus pelvic girdle) during pushups. Paired trials were conducted with adult males and females using a robot that performed M. bivittatus signature displays and that differed on its two sides in epaulet attributes. We quantified two kinds of bobbing displays in subjects: signature displays and two-bob displays. We also computed a composite response (CR) score, in which point values were assigned to types of nonbobbing displays and display combinations according to the apparent level of subject aggression. Results of Experiment 1 showed that males (but not females) performed more signature displays to the side of the robot with the epaulet present than to the side with the epaulet absent, suggesting that epaulets serve a signaling function. Composite response scores did not differ between treatments for either sex. In Experiment 2 neither males nor females performed more bobbing displays to an enlarged epaulet than to an epaulet reduced in size. However, males exhibited greater CR scores to the enlarged epaulet, suggesting that epaulet size or conspicuousness is important to its function. In Experiment 3 neither sex produced more bobbing displays to an epaulet on the robot's shoulder than to one on its hip. Yet, males accumulated significantly larger CR scores in response to the shoulder epaulet than to the hip epaulet, indicating that males were aware of normal epaulet location. Finally, in Experiment 4, where our robot performed hindlimb rather than forelimb pushups, subjects failed to exhibit more bobbing displays in response to a shoulder epaulet than to a hip epaulet. CR scores also did not differ between treatments for either sex, perhaps due to the striking abnormality of hindlimb-driven bobbing displays. Although the function of M. bivittatus epaulets remains elusive, these markings clearly are salient to male conspecifics.

Juvenile hormone regulates the photoperiodic plasticity of elytra coloration in the ladybird Harmonia axyridis.

Many animals, including insects, exhibit plasticity of body colour in response to environmental changes. Varied expression of carotenoids, major cuticle pigments, significantly contributes to body colour flexibility. However, the molecular mechanisms by which environmental cues regulate carotenoid expression remain largely unknown. In this study, we used the ladybird Harmonia axyridis as a model to investigate the photoperiodic-responsive plasticity of elytra coloration and its endocrine regulation. It was found that H.axyridis females under long-day conditions develop elytra that are much redder than those under short-day conditions, resulting from the differential accumulation of carotenoids. Exogenous hormone application and RNAi-mediated gene knockdown indicate that carotenoid deposition was directed through the juvenile hormone (JH) receptor-mediated canonical pathway. Moreover, we characterized an SR-BI/CD36 (SCRB) gene SCRB10 as the carotenoid transporter responding to JH signalling and regulating the elytra coloration plasticity. Taken together, we propose that JH signalling transcriptionally regulates the carotenoid transporter gene for the photoperiodic coloration plasticity of elytra in the beetles, which reveals a novel role of the endocrine system in the regulation of carotenoid-associated animal body coloration under environmental stimuli.

Scorpionfish rapidly change colour in response to their background

BackgroundTo facilitate background matching in heterogenous environments, some animals rapidly change body colouration. Marine predatory fishes might use this ability to hide from predators and prey. Here, we focus on scorpionfishes (Scorpaenidae), well-camouflaged, bottom-dwelling sit-and-wait predators. We tested whether Scorpaena maderensis and Scorpaena porcus adjust body luminance and hue in response to three artificial backgrounds and thereby achieve background matching. Both scorpionfish species are also red fluorescent, which could contribute to background matching at depth. Therefore, we tested whether red fluorescence is also regulated in response to different backgrounds. The darkest and the lightest backgrounds were grey, while the third background was orange of intermediate luminance. Scorpionfish were placed on all three backgrounds in a randomised repeated measures design. We documented changes in scorpionfish luminance and hue with image analysis and calculated contrast to the backgrounds. Changes were quantified from the visual perspective of two potential prey fishes, the triplefin Tripterygion delaisi and the goby Pomatoschistus flavescens. Additionally, we measured changes in the area of scorpionfish red fluorescence. Because scorpionfish changed quicker than initially expected, we measured luminance change at a higher temporal resolution in a second experiment.ResultsBoth scorpionfish species rapidly adjusted luminance and hue in response to a change of background. From prey visual perspective, scorpionfishes’ body achromatic and chromatic contrasts against the background were high, indicating imperfect background matching. Chromatic contrasts differed considerably between the two observer species, highlighting the importance of choosing natural observers with care when studying camouflage. Scorpionfish displayed larger areas of red fluorescence with increasing luminance of the background. With the second experiment, we showed that about 50% of the total luminance change observed after one minute is achieved very rapidly, in five to ten seconds.ConclusionBoth scorpionfish species change body luminance and hue in response to different backgrounds within seconds. While the achieved background matching was suboptimal for the artificial backgrounds, we propose that the observed changes were intended to reduce detectability, and are an essential strategy to camouflage in the natural environment.

Sexual dimorphism in dynamic body color in the green anole lizard

Animals capable of rapid (i.e., physiological) body color change may use color to respond quickly to changing social or physical environments. Because males and females often differ in their environments, the sexes may use changes in body color differently, reflecting sexual dimorphism in ecological, behavioral, or morphological traits. Green anole lizards, Anolis carolinensis, frequently switch their dorsal body color between bright green and dark brown, a change that requires only seconds, but little is known regarding sexual dimorphism in their color change. We tested three hypotheses for the function of body color (thermoregulation, camouflage via background-matching, and social communication) to determine the ecological role(s) of physiological color change in anoles. First, we examined instantaneous body color to determine relationships between body color and body temperature, substrate color and type, and whether these varied between the sexes. Next, we examined the association between color change and behavioral displays. Altogether, we found that males were more likely to be green than females, and larger lizards were more often green than smaller ones, but there was no evidence that anole body color was associated with body temperature or background color during the summer breeding season. Instead, our results show that although the sexes change their color at approximately the same rates, males changed color more frequently during social displays, while females remained green when displaying. In sum, social communication appears to be the primary function of anole color change, although the functions of body color may differ in the nonbreeding season.Significance statementMany animals can change their body color in response to their environments, and in many species, males and females experience different environments. In this study, we examined whether the sexes of green anole lizards use the ability to rapidly change their body color between green and brown for different functions. We found that, when a lizard was first sighted, its body color did not appear to match its background color in either sex (suggesting that color change does not contribute to avoidance of detection by potential predators), and body color was not associated with temperature for either sex (i.e., color was unlikely to influence body temperature). Yet, males changed color more often when performing social displays to other lizards, while females remained green during social displays. Thus, rapid color change plays an important role in social communication in both sexes, highlighting how males and females may use the same behavior to convey different messages.

Unilateral erythema in a newborn

A 10-day-old newborn male was referred to our clinic for the evaluation of congenital dermal melanocytosis. During the physical examination, when the baby was lying on his side, a sharply demarcated erythema involving half of his body was noticed (Figure 1). The change of colour lasted a few minutes. The baby was otherwise healthy, and no additional signs were observed. The baby's mother reported only one other isolated similar episode of about the same duration occurring at home when the baby was lying naked on the changing table. HP is a rare event that consists of a sudden unilateral transient change in skin colour with a sharp demarcation along the body midline, resulting in two different body colours.1 HP usually occurs between the 3rd and 4th day of life, and typically appears when the baby is lying on the side and may last from 30 s up to 20 min. It can be a single event or it can be recurrent. Newborns can experience several episodes in just a few days.2 Pathophysiology of HP is still not completely clear although there is evidence to support a sympathetic autonomic dysfunction, probably because of hypothalamic immaturity in the newborn.2 HP represents a benign condition although it has also been reported in the context of hypoxia and as an epiphenomenon of central nervous system disorders such as meningitis, hypothalamic and brain stem lesions or sympathetic nervous system lesions. Exacerbation has been described in patients receiving treatment with prostaglandin E1.1, 3 While the clinical characteristics of HP make it easily distinguishable, a differential diagnosis should include infectious neonatal skin rashes, such as parechovirus, herpes virus and candida infection, neonatal lupus erythematosus and capillary malformations such as those in the PROS spectrum and cutis marmorata telangiectatica congenita. HP can be a manifestation of the rare disorder paroxysmal extreme pain disorder, part of SCN9A neuropathic pain syndromes, a group of sodium channelopathies where systemic symptoms such as tonic nonepileptic attacks and syncope with bradycardia are associated with the transient skin colour change.4 HP is a benign and self-resolving phenomenon. As mentioned, only in rare circumstances HP is a manifestation of central nervous system disorders in association with other signs and symptoms and never presenting as the sole clue of such conditions.5 The recognition of the phenomenon is therefore important since, while being certainly peculiar, it does not require further investigations or therapeutic measures. Alice Nadia Rossi wrote the first draft of the manuscript and adjusted it according to the comments of the other authors. Francesco Paolo Salamone collected data and clinical images and helped writing the manuscript. Martina Mussi participated in data collection. Marco Adriano Chessa participated in the revision of the manuscript. Iria Neri carried out the final revision of the manuscript before submission. All of the authors participated in the preparation of the manuscript. There are no prior publications or submissions with any overlapping information, including studies and patients. This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. The authors declare no conflicts of interest. All patients in this manuscript have given written informed consent for participation in the study and the use of their de-identified, anonymized, aggregated data and their case details (including photographs) for publication. Data sharing is not applicable to this article as no new data were created or analysed in this study.

Coris picta, a new record of the Comb wrasse (Perciformes: Labridae) from Korea

Based on a single specimen (100.3 mm SL) collected from the southern coastal waters of Jejudo Island, Coris picta is described as the first record from Korea. It is characterized by having a broad black stripe from tip of snout to posterior edge of caudal fin along lateral body in terminal phase, 12 soft rays in dorsal and anal fins, 82 lateral line scales, and a single mid-dorsal dark stripe on head. We propose new Korean names, “A-ssi-nol-re-gi-sog”, and “Bis-sal-a-ssi-nol-re-gi”, for the genus and the species named after dramatic change of body color with growth and having a comb-like stripe on lateral body, respectively.

Astaxanthin mitigates oxidative stress caused by microplastics at the expense of reduced skin pigmentation in discus fish

Microplastics (MPs) exposure generally triggers oxidative stress in fish species and vertebrate pigmentation is commonly influenced by oxidative stress, but MPs-induced oxidative stress on fish pigmentation and body color phenotype has not been reported. The aim of this study is to determine whether astaxanthin could mitigate the oxidative stress caused by MPs but at the expense of reduced skin pigmentation in fish. Here, we induced oxidative stress in discus fish (red skin color) by 40 or 400 items/L MPs under both astaxanthin (ASX) deprivation and supplementation. We found that lightness (L*) and redness (a*) values of fish skin were significantly inhibited by MPs under ASX deprivation. Moreover, MPs exposure significantly reduced ASX deposition in fish skin. The total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity in fish liver and skin were both significantly increased with the increase of MPs concentration, but content of glutathione (GSH) in fish skin showed a significant decrease. For ASX supplementation, the L*, a* values and ASX deposition were significantly improved by ASX, including the skin of MPs-exposed fish. The T-AOC and SOD levels changed non-significantly in fish liver and skin under the interaction of MPs and ASX, but ASX significantly reduced GSH content in fish liver. Biomarker response index indicated that ASX could improve the moderately altered antioxidant defense status of MPs-exposed fish. This study suggests that the oxidative stress caused by MPs was mitigated by ASX but at expense of reduced fish skin pigmentation.

Application of Kansei engineering to Turkish coffee makers: Connections between hedonic factors and design features

The market share of small household appliances has grown tremendously in recent years. Varied innovation methods are applied in developing small household appliances, including Turkish Coffee Makers; however, Kansei Engineering has not yet been carried out in this field. This paper aims to conduct Kansei Engineering methodology on these machines to provide design inputs for industrial designers. The domain of the study is Turkish Coffee Makers with one pot and without a water tank, and the target is between 20–40 aged Turkish people. 382 participants attended the study, and 16 stimuli were utilised. The study methods are extracting Kansei words, selecting product properties, affinity diagram, SD Questionnaire, factor, descriptive, and PLS analyses. The results suggest that designers can generate Turkish Coffee Makers with Square with fillet as the top view, Trapezoid as the front view, C-shape cornered as the right view, and two colours as the main body colour; and design these products depending on the design factors of stylish, easy to use, joyful, trend follower, functional, desirable, youthful, dissimilar, and luxurious to succeed in the market. As a result, product designers might determine the product properties more efficiently via the findings of this study.

Four new species of coral- and rock-boring polychaetes Daylithos (Annelida, Flabelligeridae) from the Pacific Ocean

Four new species of Daylithos (Flabelligeridae, Annelida) are described, based on specimens collected from rocks and corals of Japan and Malaysia. Daylithos, contains one species, D. parmatus, currently reported from Japan. However, the specimens described in previous reports were unable to be located and thus deemed lost. Therefore, it was unclear whether the specimens described as D. parmatus in those studies were, indeed, the species. In Malaysia, D. parmatus has also been known as popular species from corals. The specimens collected from Langkawi (Malaysia) showed clearly different characters from D. parmatus and other congeners. In this study, we describe four new species, Daylithos japonicus, D. amamiensis, D. sugashimaensis and D. langkawiensis, based on newly-collected specimens from several part of Japan and Malaysia. These new species can be discriminated from other congeners by body colour, presence of eyes, shape of dorsal shield, length of caruncle and arrangement of neurochaetae. We have also provided mitochondrial cytochrome c oxidase subunit I sequences of the new species.

Identification of Novel Mutations in the Tyrosinase Gene (TYR) Associated with Pigmentation in Chinese Giant Salamanders (Andrias davidianus)

The Chinese giant salamander (Andrias davidianus), an endangered amphibian species endemic to China, has been previously evaluated with regards to its phyletic evolution, zooecology, and ethology, but molecular mechanisms underlying its skin pigmentation remain unknown. Herein, a skin transcriptome database of different colored salamanders was established using RNA-seq, and a total of 47,911 unigenes were functionally annotated. Among these unigenes, a total of 1252 differentially expressed genes (DEGs) were annotated in the seven public databases, and six DEGs were validated by qPCR between five different skin colors and eight tissues. The results showed that TYR, TYRP1, and ASIP were significantly differentially expressed between different body colors, while TYR, TYRP1, and DCT were highly expressed in skin tissue. The full-length complementary DNA of TYR was cloned and analyzed between normal and yellow phenotypes. Three nucleotide sequence deletion sites were identified in the coding region of TYR, leading to premature termination of transcription and translation in yellow individuals. Our study provides useful data for the further study of the molecular mechanisms of melanin formation, and a valuable reference for the breeding of specific skin colors in other salamanders.

The “True Colours” of Golden Loaches (Teleostei: Cobitidae)

Loaches of the genus Sabanejewia are model organisms for many ichthyologic studies focusing on morphological and colour variation. The bright lateral spots—a part of the mimicry of this fish—cause a taxonomic puzzle. Common practice is that morphometric and molecular studies lack habitat assessments of species originating from different environments. In this study, we analysed body shape and colour variation within two species of Sabanejewia in order to reveal whether they are more affected by phylogeny or environmental conditions. The environmental parameters were obtained using satellite mapping tools, body shape using geometric morphometry, and the molecular identification of specimens using an analysis of mitochondrial DNA (sequence of the cytochrome b gene). Generalized linear mixed models were used for the analysis of lateral spot numbers, and principal components analysis to describe the changes in landmark position defined by the permutation tests. Results show a significant impact of the locality elevation and specimen’s sex on the change of the body shape. We identified significant differences in the number of lateral spots, which are considered mimicry variation across an elevation gradient. Morphological differences of Sabanejewia spp. vary with ecological factors along the river continuum.

Distribution and Phylogenetic Position of the Antarctic Ribbon Worm Heteronemertes longifissa (Nemertea, Pilidiophora)

To date, a total of 23 valid species of heteronemerteans belonging to 15 genera have been recorded in Antarctic and Subantarctic waters. The ribbon worm Heteronemertes longifissa (Hubrecht, 1887) is the only heteronemertean species reported to have bipolar distribution, but this statement is doubtful. The phylogenetic relationships of H. longifissa to other heteronemerteans remain uncertain. A genetic analysis of specimens from Antarctica has shown that the name H. longifissa refers to two sibling species with an uncorrected p-distance of 5.3% in COI. These species differ in body color: one is whitish, and the other is grayish-pink. The species with the whitish body has been reliably identified from off the Norway coast (as Cerebratulus sp. NemBar1383 (BOLD: ACM5920)), i.e., it has a bipolar distribution. A molecular phylogenetic analysis of Lineidae based on five gene markers (COI, 16S, 18S, 28S, and histone H3) has shown the genus Heteronemertes to belong to Lineage D of Clade 2 sensu Kajihara et al., 2022 (crown Lineidae). The phylogenetic positions of four more species of unidentified lineids are currently under discussion.

The Plastic Larval Body Color of the Pale Grass Blue Butterfly Zizeeria maha (Lepidoptera: Lycaenidae) in Response to the Host Plant Color: The Maternal Effect on Crypsis.

Many lepidopteran larvae show body color polyphenism, and their colors may be cryptic on the host plant leaves. To elucidate the effect of the host plant color on the plastic larval body color, we focused on the lycaenid butterfly Zizeeria maha, which shows various larval body colors ranging from green to red, even within a sibling group. We showed that oviposition was normally performed on both green and red leaves, despite a green preference and the fact that the larvae grew equally by consuming either green or red leaves. The number of red larvae decreased from the second instar stage to the fourth instar stage, demonstrating a stage-dependent variation. When the larvae were fed either green or red leaves across multiple generations of the lineages, the red larvae were significantly more abundant in the red leaf lineage than in the green leaf lineage. Moreover, the red-fed siblings showed a significantly higher red larval frequency than the green-fed siblings in the red-leaf lineage but not in the green-leaf lineage. These results suggest that, in this butterfly species, the plastic larval body color for crypsis may be affected not only by the color of the leaves that the larvae consume (single-generation effect) but also by the color of the leaves that their mothers consume (maternal effect), in addition to a stage-dependent color variation.

Additional Records of the Elusive Lateritic Plateau Toad <i>Beduka koynayensis</i> (Soman, 1963) (Anura: Bufonidae) from the Surroundings of its Type Locality with an Insight into the Genetic Data

The Koyna Toad, Beduka koynayensis, was described some 50 years ago as Bufo koynayensis. Due to taxonomic changes in the generic position now the species is considered under the recently established genus Beduka. Although the terrestrial toad species are morphologically cryptic and difficult to identify them based on morphological characters alone the members of Beduka are exceptions due to clear body colour patterns and habitat specificity. Even though the species is well studied in terms of reproductive biology, call pattern and life history traits there is a lacuna in the understandings of its range of distribution, morphological and genetic variations due to limited field samples available in the museums and the genetic data availability in the GenBank. Based on the fresh collections around the type locality, here we report morphological variations across the different populations within the species. With the 16S rRNA generated in the study discussions are made on the genetic variations across its range of distribution utilizing the unpublished sequences available in the GenBank.

Smaller, lighter coloured and less hairy Procladius (Diptera, Chironomidae) in warmer climate

The relationship between body size, colour and hairiness of Procladius of the Diptera family Chironomidae and climate measured as annual mean air temperature was analysed. The study was based on 453 males representing 31 species from 253 localities in 27 countries in Europe and six elsewhere. Wing length as well as three other characters reflecting body size showed significant decrease with warmer climate conditions. The results are in line with several other studies of insects concluding that adult insects are smaller in warmer climate, also considering the implications of global warming. Likewise, all five characters representing colour lightness showed significantly lighter coloured Procladius specimens with warmer climate. The relationship between hairiness and annual mean air temperature was weaker than that of size or colour and temperature, but all five characters studied showed a statistically significant decrease in hairiness with warmer climate. The biological relevance of smaller size, lighter colour and less hairiness in warmer climate can be related to several factors regulating flight and swarming, including less need of protection against cold weather, overheating avoidance, mating success agility and predator escape.

Genesis of the Body Color of Brazilian Gem-Quality Yellow-Green Opal

The chromaticity characterization and influencing factors of the body color of 28 yellow-green opals were studied through Fourier transform infrared spectrum (FTIR), energy-dispersive X-ray fluorescence spectroscopy (ED-XRF), ultraviolet-visible spectroscopy (UV-vis) and X-Rite SP62 spectrophotometer. It was found that the hue h° and the iron content of the yellow-green opal were highly negatively correlated, the chroma C* and the sum of nickel and iron content were significantly positively correlated, and the lightness L* was significantly negatively correlated with the chromium content. The body color of light green opal is mainly caused by nickel. The iron content will make the color yellow, and the chromium content will darken the green. With the increase of Fe content, the lowest absorption value of UV-vis absorption at 500–650 nm moves towards the long wave direction, and the hue h° decreases. With the increase of the total content of Ni and Fe, the 650 nm absorption peak area and the chroma C* increase. Under CIE D65 standard light source and N9.5 Munsell neutral background, using K-Means clustering method, 28 yellow-green opal body colors were divided into three grades: (1) Fancy Intense, (2) Fancy Deep and (3) Fancy.

Revealing anole diversity in the highlands of the Northern Andes: New and resurrected species of the Anolis heterodermus species group

The Anolis heterodermus group comprises eight big-headed and short-legged lizard species from the highlands of the northernmost South American Andes. Recent studies revealed unknown lineages within this group that had previously been categorized as a species complex. By widely sampling and applying an integrative taxonomic framework, we (1) assessed the species diversity of the group using a molecular dataset (two mitochondrial and one nuclear markers) along with an inclusive morphological study (scalation, scale configuration and ornamentation, morphometrics, and dewlap and body colour patterns); and (2) we inferred the evolutionary relationships within this species group. Our analyses confirmed the formerly reported differentiation between populations of those high-altitude lizards, and we identified several unknown evolutionary lineages. Our results provided evidence for the existence of nine distinct, independently evolving evolutionary lineages in the heterodermus group. As a result, we described two morphologically and genetically highly distinct lineages as species new to science (A. quimbayasp. nov. and A. tequendamasp. nov.). We redescribed A. heterodermus and erected as a valid species Anolis richteri, a previously described synonym of A. heterodermus. A taxonomic key for the identification of species of the Phenacosaurus clade was presented. The identification of two additional poorly-known lineages suggested that the diversity of this group of lizards is still unknown; therefore, it is necessary to establish measurements for the group´s conservation, as well as to perform fieldwork and revision of herpetological collections to identify possible hidden diversity within the group.

Sex separation by body color via a W-chromosome-linked transgene

Sex separation processes are important for commercial insect production and sterile insect techniques. Here, we describe the transgenic insertion of a DsRed expression cassette driven by the enhancer HR3 and strong promoter IE1 into the silkworm W chromosome as a dominant visible marker of sex separation. The obtained transgenic lines showed female-specific body color visible to the naked eye at the second- to fifth-instar larval, pupal and adult stages, and their performance traits were comparable to those of a nontransgenic practical silkworm variety. This strategy can greatly facilitate the sex separation of silkworms for male-only rearing and to obtain hybrids while avoiding sibling mating, and it can also be applied to the sex separation of other light-colored insects.

Taxonomic insights and evolutionary history in East Asian terrestrial slugs of the genus Meghimatium

East Asia, specifically the Japanese Archipelago, is a biodiversity hotspot of both vertebrates and invertebrates. Mollusks represent a burst of species diversity in this region due to the effects of biotic and abiotic factors on their morphological traits, such as shell shape and size. However, the evolutionary history of terrestrial slugs in East Asia remains unknown. In the present study, we investigated the molecular phylogeny of terrestrial slugs of the genus Meghimatium. This genus includes three described and eight undescribed species, and our study used all except for two. Based on phylogeny and the species delimitation tests, the genus Meghimatium was split into many putative species, suggesting higher species diversity than previously thought based on morphological and anatomical studies and that almost undescribed species may be inappropriate. Therefore, morphological traits, such as body size and colour, conventionally considered for classification may easily vary or be similar across geographic region. Moreover, the divergence time of this genus is almost concordant with the geographical time scale of the formation of the Japanese mainland. Our findings suggest that molecular phylogenetics helps classify Japanese Meghimatium slugs, but comprehensive taxonomic revisions using multi-locus analyses are needed.