Ventral Pattern Research Articles

Morphological characterization and sexual dimorphism of saw-scaled viper (<em>Echis</em>: viperidae: ophidia) population in Sri Lanka

The Saw-scaled vipers (SSV) of the genus Echis (Viperidae: Ophidia) primarily inhabit tropics. In Sri Lanka, E. carinatus is densely populated in the Northern Province where they account for over 50% of the local snakebites. Although it was initially reported as a unique Sri Lankan subspecies named E. c. sinhaleyus, its existence was later questioned, urging the need for more detail studies. The present study examined morphological characters and sexual dimorphism in 30 specimens (17 males and 13 females) collected from Kilinochchi and Jaffna Districts in the Northern Province, using 12 mensural and 17 meristic traits, updating Deraniyagala’s report of 1951. Results showed that the adult females have longer snout to vent length (SVL) than that of males (280.34±43.32 vs. 240.88±27.03), revealing a positive sexual dimorphism index. Males had a greater TL/SVL ratio (x̄̄=13.89±0.68) than that of females (x̄̄=10.65±085). ANCOVA test retrieved most accurate and an independent significant effect of ‘sex’ on TL while SVL serving as the covariate. Males and females shared consistent meristic characters, except for number of dorsal scales at the lower part of the body, ventral and sub-caudal scales. There were more ventral scales in females (145.54±3.31) than that of males (138.41±4.08), and sub-caudal scales were higher in number in males (28.94±1.85) than that of females (25.85±2.82). Although, there were some colour pattern variations of the specimens, (head pattern and ventral pattern), they were not sex-associated and distributed evenly between males and females. This is the first study to illustrate the detail morphometric characters; mensural traits; meristic traits, and color patterns and to demonstrate the sexual dimorphism in the SSV from Sri Lanka, with noticeable differences in the snoutvent length (SVL), tail length (TL), ventral scales, and sub-caudal scales between male and female.

First report of the genus Bostocktrachys Hirschmann, 1979 from India (Acari, Mesostigmata, Uropodina, Trachyuropodidae) with the description of a new species and with note to the ontogeny of the genus

The first representatives of the genus Bostocktrachys Hirschmann, 1979 have been discovered in India and are described here as Bostocktrachys wisniewskii sp. nov. based on females, males and nymphs. The new species differs from its congeners on the basis of the shape of grooves on the dorsal shields, dorsal and ventral setae and dorsal and ventral culptural pattern. The second deutonymph and the first protonymph of this genus are presented and discussed.

Genetic Diversity, Kinship, and Polychromatism in the Spotted Eagle Ray Aetobatus ocellatus of Fiji

The spotted eagle ray Aetobatus ocellatus (Kuhl, 1923) has a widespread Indo-West Pacific distribution and displays substantial population genetic structuring. Genetic data are crucial for understanding the species’ diversity, connectivity, and adaptation. However, molecular genetic information on A. ocellatus from Melanesia is lacking, which impedes our understanding of gene flow among geographic regions. In this study, we sampled 45 A. ocellatus, primarily from Fiji’s largest fish market in the capital, Suva. Mitochondrial DNA Cytochrome C Oxidase subunit I (COI) barcoding was used for species identification, and DArT-seqTM technology was applied to assess the nuclear genetic diversity. Barcoding of the COI gene showed a 98.6% to 99.8% similarity to A. ocellatus reference sequences in the Barcode of Life Data System, and the 45 individuals were represented by three major evolutionary haplotype clusters. Genotyping resulted in 24,313 Single-Nucleotide Polymorphisms (SNPs) which were quality-filtered to 7094 SNPs per individual. The observed heterozygosity level was 0.310. The inbreeding coefficient was positive, and genotyping identified one full-sibling pair and one half-sibling pair from the 45 individuals. Additionally, eagle rays exhibit polychromatic patterns, and at least three ventral pattern variations were recorded in specimens from the market. Collectively, our main findings characterize the genetic profile of A. ocellatus in Fiji and can help to understand the diversification of this species within the region.

New specimens of Helicops boitata (Serpentes: Dipsadidae: Hydropsini), with data on morphological variation and behavior

We report data on morphological variation and behavior of the recently described watersnake Helicops boitata, previously known strictly from the holotype. Our data come from five new specimens fortuitously found in a private area near the type locality, in the Brazilian Pantanal wetlands. The expanded sample revealed polymorphism in at least two scalation features previously assumed as diagnostic of the species (i.e., undivided condition of the cloacal plate and nasal scales) and confirmed the uniqueness of the ventral color pattern, as well as the divided condition of the foremost ventral shields. In addition, three individuals collected alive also exhibited the same harmless behavior reported to the holotype, a rather unusual feature among snakes of the genus Helicops. Other new behavioral observations include mostly nocturnal activity (in contrast with the previous data) and the ability to dig galleries in the soft substrate when attempting to escape. The finding of five individuals very close to each other suggest aggregations in habitats prone to retain humidity in the dry season of the Pantanal. Low abundance rates and possible habitat restrictions might render Helicops boitata particularly susceptible to seasonal fire episodes that consume large extensions of the wetlands, including temporarily dry flooding fields in which aquatic reptiles find refuge during the seasonal droughts.

How to find a wolverine: Factors affecting detection at wolverine (Gulo gulo) bait stations in western Canada

AbstractHigh individual detection success enables precise estimates of density and the ability to monitor trends in abundance for wolverine and other low‐density species, information that is critical for the implementation and assessment of conservation measures. We evaluated a dataset that included six different wolverine capture–recapture studies over a large gradient in wolverine (Gulo gulo) density to provide recommendations for increasing detection. We examined factors related to bait station components, habitat, and seasonal timing. Accounting for variation in wolverine density and trap duration, our results suggest that bait stations setups having a run pole, frame, and camera to photograph unique ventral color patterns, in addition to hair snag devices, identify more individual wolverine than those without. The presence of snow is a habitat feature that also increases individual detection. Female detection rates were lower than male detection rates at the onset of the reproductive denning season in late February and early March compared with January and early February. We found latency to detection was independent of wolverine density, but greater in areas with human influence. Relatively high rates of genotyping success (55%) were predicted by even a single guard hair left at bait stations, while underfur required ~15 hairs for similar success. Longer sampling intervals reduced genotyping success in spring, more so for underfur than guard hair. Hair samples acquired from barbwire were of higher quality than those from either alligator clips or gun brushes. To improve individual detection for wolverine inventory and monitoring, we recommend deploying run pole setups in areas with low human disturbance that will retain snow into late spring. Extending the winter trapping effort into April and May could increase the chances of detecting denning females. Latency to detection suggests that traps should be active for more than a month, especially in human‐influenced areas, but genotyping success suggests that traps should also be cleared of hair samples at smaller intervals of a month or less, during late winter/spring.

Seasonal Alternation of Putative Camouflage Wing Morphs of the American Snout Butterfly (Libytheana carinenta).

AbstractIntraspecific variation in camouflage is common in animals. Sexual dimorphism in camouflage is less common and, where observed, attributed to trade-offs between natural selection for predator avoidance and sexual selection for conspicuous mating signals. Here we report on variation in putatively cryptic ventral hindwing patterns in the American snout butterfly, Libytheana carinenta. We use field surveys and crowdsourced data to characterize three morphs. One is found in both sexes, one is male specific, and one is female specific. The sex-specific morphs constitute a sexually dimorphic set whose frequencies change together in time. Field surveys indicate that butterflies in southern Arizona transition from midsummer dominance of the sexually monomorphic pattern to early-fall dominance of the sexually dimorphic set. Crowdsourced data indicate that the sexually dimorphic set dominates in early spring, transitioning later into a mixture of morphs dominated by the monomorphic pattern, with the dimorphic set rising in frequency again in late fall. We discuss this unique pattern of camouflage variation with respect to contemporary theory on animal coloration.

Variation in Ventral Coloration Pattern and Aposematism in Tropical Warty Newts.

Aposematic coloration plays a crucial role in animal defense, and it is shaped by a complex interplay of factors such as physiological limitations and sexual and natural selection. Warty newts within the genus Paramesotriton exhibit significant variation in ventral coloration. In this study, we quantified the percentage of red ventral area to investigate aposematic ventral coloration in Paramesotriton deloustali and P. guangxiensis across eight populations in northern Vietnam. To assess the interaction between predators and the aposematic signals, we conducted experiments employing three types of clay replicas of newts: dorsal, red ventral, and black ventral models. Our findings revealed a significant variation in the red ventral area among different populations. Additionally, a significant correlation was detected between the red ventral area of the newt and the annual temperature range. In clay model experiments, a significant difference in predator attack rates was observed between dorsal and ventral clay models. Interestingly, there was no significant difference in attack rates between red and black ventral types. Our study suggested that the variation in the red ventral area of warty newts is probably influenced by multiple factors, including genetic constraints, sex, ambient environment, and diet. Furthermore, our results supported the effectiveness of displaying aposematic coloration as an antipredator defense mechanism in warty newts. However, variations in body size and the pressure of mammal predation might not play a significant role in determining aposematic coloration.

Identification of pre-flexion fish larvae from the western South Atlantic using DNA barcoding and morphological characters.

Knowledge on species composition is the first step necessary for the proper conservation and management of biological resources and ecologically relevant species. High species diversity and a lack of diagnostic characters for some groups can impose difficulties for taxonomic identification through traditional methodologies, and ichthyoplankton (fish larvae and eggs) are a good example of such a scenario. With more than 35.000 valid species of fishes worldwide and overall similar anatomies in early developmental stages in closely related groups, fish larvae are often hard to be identified at the species or even more encompassing taxonomic levels. To overcome this situation, molecular techniques have been applied, with different markers tested over the years. Cytochrome c oxidase I (COI) is the most commonly used marker and now has the broadest public reference libraries, providing consistent results for species identification in different metazoan studies. Here we sequenced the mitochondrial COI-5P fragment of 89 fish larvae collected in the Campos Basin, coastal southeastern Brazil, and compared these sequences with references deposited in public databases to obtain taxonomic identifications. Most specimens identified are species of the Blenniiformes, with Parablennius and Labrisomus the most frequently identified genera. Parablennius included two species (P. marmoreus and P. pilicornis), while Labrisomus included three species (L. cricota, L. conditus and L. nuchipinnis). Anatomy of these molecularly identified specimens were then analyzed with the intention of finding anatomical characters that might be diagnostically informative amongst the early development stage (pre-flexion) larvae. Ventral pigmentation patterns are proposed as useful markers to identify Labrisomus species. However, additional specimens are needed to confirm if the character holds stability through the geographic distribution of the species.

African penguins utilize their ventral dot patterns for individual recognition

African penguins utilize their ventral dot patterns for individual recognition

A New Miniature Species of Arthroleptis (Anura: Arthroleptidae) from Nyungwe National Park, Rwanda

A new, very small-sized species of Arthroleptis is described from western Rwanda. The new species occurs locally endemic in Nyungwe Forest and Cyamudongo Forest, where it inhabits the leaf litter of montane forests between 1800 and 2200 m a.s.l. It differs from all other members of the genus by a unique combination of morphological characters, including size (SVL of adult males 16.0–16.5 mm), skin texture, length of hindlimbs, and ventral colour pattern; by characteristics of its advertisement call that consists of a single note lasting 17.4 ± 6.4 [11–32] ms and has a dominant frequency of 5861 ± 188 [5531–6029] Hz; and also in the sequence of the 16S rRNA gene that differs from available homologous sequences of other species of the genus by an uncorrected p-distance of at least 4.6%. Details of the natural history as well as two additional call types are described.

Wing pattern diversity in Eunica butterflies (Nymphalidae: Biblidinae): phylogenetic analysis implies decoupled adaptive trends in dorsal sexual dimorphism and ventral eyespot evolution.

Butterfly eyespots are wing patterns reminiscent of vertebrate eyes, formed by concentric rings of contrastingly coloured scales. Eyespots are usually located close to the wing margin and often regarded as the single most conspicuous pattern element of butterfly wing colour displays. Recent efforts to understand the processes involved in the formation of eyespots have been driven mainly by evo-devo approaches focused on model species. However, patterns of change implied by phylogenetic relationships can also inform hypotheses about the underlying developmental mechanisms associated with the formation or disappearance of eyespots, and the limits of phenotypic diversity occurring in nature. Here we present a combined evidence phylogenetic hypothesis for the genus Eunica, a prominent member of diverse Neotropical butterfly communities, that features notable variation among species in eyespot patterns on the ventral hind wing surface. The data matrix consists of one mitochondrial gene region (COI), four nuclear gene regions (GAPDH, RPS5, EF1a and Wingless) and 68 morphological characters. A combined cladistic analysis with all the characters concatenated produced a single most parsimonious tree that, although fully resolved, includes many nodes with modest branch support. The phylogenetic hypothesis presented corroborates a previously proposed morphological trend leading to the loss of eyespots, together with an increase in the size of the conserved eyespots, relative to outgroup taxa. Furthermore, wing colour pattern dimorphism and the presence of androconia suggest that the most remarkable instances of sexual dimorphism are present in the species of Eunica with the most derived eyespot patterns, and are in most cases accompanied by autapomorphic combinations of scent scales and "hair pencils". We discuss natural and sexual selection as potential adaptive explanations for dorsal and ventral wing patterns.

Which side are you on? Spider web positioning affects prey capture more than body colour

Colour has been hypothesized to play a crucial role in prey capture for sit-and-wait predators that rely on visual cues to deceive their prey. Prey capture success has been directly linked to colouration in spiders; however, evidence so far focuses mostly on dorsal colouration, excluding ventral patterns that are visible to prey and may be relevant for prey attraction. Here, we explored whether the dorsal and ventral colouration of a colour polymorphic spider is associated with light environment and prey capture success. We quantified the number of prey captured across three dorsal (black, white, and yellow) and two ventral (black and a mosaic yellow/orange pattern) morphs of Gasteracantha cancriformis, considering light intensity on dorsal and ventral sides. We found that spiders capture more prey in low light environments, and that individuals often expose their dorsal colouration towards low light levels. We did not find significant differences in prey capture rate between morphs dorsally or ventrally. These results indicate that how and where spiders position their web can be more important for prey capture than colouration. Alternative hypotheses such as aposematism, camouflage and thermoregulation deserve more attention in future studies that aim to understand the role of colouration in spiders and the factors causing spider colour polymorphisms.

Effects of social context manipulation on dorsal and ventral hippocampal neuronal responses.

The hippocampus is critical for contextual memory and has recently been implicated in various kinds of social memory. Traditionally, studies of hippocampal context coding have manipulated elements of the background environment, such as the shape and color of the apparatus. These manipulations produce large shifts in the spatial firing patterns, a phenomenon known as remapping. These findings suggest that the hippocampus encodes and differentiates contexts by generating unique spatial firing patterns for each environment a subject encounters. However, we do not know whether the hippocampus encodes social contexts defined by the presence of particular conspecifics. We examined this by exposing rats to a series of manipulations of the social context, including the presence of familiar male, unfamiliar male and female conspecifics, in order to determine whether remapping is a plausible mechanism for encoding socially-defined contexts. Because the dorsal and ventral regions of the hippocampus are thought to play different roles in spatial and social cognition, we recorded neurons in both regions. Surprisingly, we found little evidence of remapping in response to manipulation of the social context in either the dorsal or ventral hippocampus, although we saw typical remapping in response to changing the background color. This result suggests that remapping is not the primary mechanism for encoding different social contexts. However, we found that a subset of hippocampal neurons fired selectively near the cages that contained the conspecifics, and these responses were most prevalent in the ventral hippocampus. We also found a striking increase in the spatial information content of ventral hippocampal firing patterns. These results indicate that the ventral hippocampus is sensitive to changes in the social context and neurons that respond selectively near the conspecific cages could play an important, if not fully understood role in encoding the conjunction of conspecifics, their location and the environment.

Living apart together: Morphological, spatial, and genetic differentiation of three sympatric rock lizard species (Lacertidae: Darevskia) of the Caucasus

Three rock lizard species (genus Darevskia) occur in the same mountain gorge of the Greater Caucasus mountains located in Northern Georgia. Whereas Darevskia caucasica and Darevskia derjugini belong to the same phylogenetic clade known as “caucasica”, Darevskia rudis is associated to the “rudis” clade. The mountain lizards differed interspecifically in their scalation and ventral colouration patterns, but the body proportions of D. caucasica and D. rudis were more similar to each other than to D. derjugini as both had flatter heads and longer limbs than D. derjugini. Females of all three species had longer trunks and shorter limbs than males. We hypothesized that hybrids occur more likely between D. derjugini and D. caucasica rather than between species belonging to different clades. However our analysis of microsatellite genotyping clearly revealed no traces of hybridisation and/or gene flow among any of the coexisting lizard species. The absence of individuals with intermediate morphological and genetic features reflects the presence of strong reproductive barriers at the prezygotic level.

Tadpoles of four sympatric megophryinid frogs (Anura, Megophryidae, Megophryinae) from Mangshan in southern China.

Sympatric distribution and potentially long larval development time make the assignment of tadpoles confusing in Asian-horned frogs of the subfamily Megophryinae. In this study, we used molecular data to identify four syntopic megophryinid tadpoles from Mangshan on the border between Hunan and Guangdong provinces in southern China: Brachytarsophryspopei, Boulenophrysshimentaina, Bo.cf.ombrophila, and Bo.nanlingensis. A detailed re-description of the Br.popei tadpoles is provided as well as the first descriptions of three Boulenophrys tadpoles based on external morphology and coloration. An effort is attempted to distinguish these tadpoles by coloration patterns: the dorsal pattern, ventral pattern, and pattern on tail are useful for field identification of these tadpoles. However, the variation of color pattern could sometimes make species delineation difficult. Researchers are encouraged to document coloration in life with photographs and the collection of tadpoles of different development stages and sizes advocated in order to better understand how color may change during larval development.

A remarkable new snake of the genus Tropidophis (Squamata: Tropidophiidae) from southern Hispaniola

A new species of Tropidophis is described from the dry forest of the Barahona Peninsula, southwestern Dominican Republic, on the Caribbean island of Hispaniola. There, the new species is parapatric with T. haetianus, the only previously known Tropidophis on Hispaniola, but exhibits striking differences in scalation (much higher number of ventral scales), in other structural morphological traits (head and body proportions), and in dorsal and ventral coloration and pattern (e.g., fewer spot rows, and a patternless head and venter, etc.). The locality of this new species lies within an area where other vertebrate species have been recently discovered, underscoring the growing appreciation of the Barahona Peninsula as a diversity hotspot. Yet, this region also remains poorly studied and it is also highly imperiled due to ongoing anthropogenic change, justifying more conservation efforts.

Different Traits, Different Evolutionary Pathways: Insights from Salamandrina (Amphibia, Caudata).

Species delimitation is often based on a single or very few genetic or phenetic traits, something which leads to misinterpretations and often does not provide information about evolutionary processes. Here, we investigated the diversity pattern of multiple phenetic traits of the two extant species of Salamandrina, a genus split only after molecular traits had been studied but the two species of which are phenetically very similar. The phenetic traits we studied are size, external body shape and head colour pattern, in a model comparison framework using non-linear mixed models and unsupervised and supervised clustering. Overall, we found high levels of intra-specific variability for body size and shape, depending on population belonging and habitat, while differences between species were generally lower. The habitat the salamanders dwell in also seems important for colour pattern. Basing on our findings, from the methodological point of view, we suggest (i) to take into account the variability at population level when testing for higher level variability, and (ii) a semi-supervised learning approach to high dimensional data. We also showed that different phenotypic traits of the same organism could result from different evolutionary routes. Local adaptation is likely responsible for body size and shape variability, with selective pressures more similar across species than within them. Head colour pattern also depends on habitat, differently from ventral colour pattern (not studied in this paper) which likely evolved under genetic drift.

Radiographic features of cardiogenic pulmonary oedema in cats with left-sided cardiac disease: 71 cases.

The aims of this study were to describe the radiographic features of cardiogenic pulmonary oedema (CPE) in a large group of cats with left-sided cardiac disease, and to determine the association between the radiographic features of CPE and the underlying cardiac disease. Thoracic radiographs of cats with CPE and echocardiographic evidence of left-sided cardiac disease and left atrial enlargement (LAE) were reviewed, and cardiac silhouette, pulmonary vessels and pulmonary parenchyma evaluation were performed. Interstitial and/or alveolar patterns were classified according to their distribution (ie, diffuse, multifocal or focal) and location (ie, craniodorsal, cranioventral, caudodorsal, caudoventral and perihilar). A Student's t-test and Mann-Whitney U-test, or the two-proportion z-test, were used to compare continuous or categorical variables, respectively, between cats affected by the two most represented cardiac diseases, namely hypertrophic cardiomyopathy (HCM) and restrictive cardiomyopathy (RCM). Seventy-one cats were included; among them, 46 (64.7%) and 13 (18.3%) had presented for HCM and RCM, respectively. Subjective and objective cardiomegaly, and subjective and objective LAE were detected in 97.2% and 91.9% of cats and in 80.3% and 40.6% of cats, respectively. Pulmonary artery abnormalities, in particular caudal pulmonary artery dilation, were found in 77.5% of cats. Pulmonary artery to pulmonary vein ratio = 1 was found in 71.8% and 55% cats on right lateral and ventrodorsal or dorsoventral views, respectively. Interstitial (57.8%) and mixed interstitial-alveolar (38%) pattern, multifocal (84.5%) and symmetrical (75%) distribution with prevalent ventrocaudal (65.6% of cats) and ventrocranial (60.9% of cats) locations were most frequently observed. No difference was found for any of these radiographic features between cats with HCM and RCM. Moderate-to-severe cardiomegaly and LAE, caudal pulmonary artery and vein dilation, as well as a ventral, multifocal and symmetrical interstitial pulmonary pattern, were the main radiographic features of CPE in evaluated cats. Underlying cardiac disease did not influence the aforementioned radiographic features.

First photographic evidence of oceanic manta rays (Mobula birostris) at two locations in the Fiji islands.

Until the revision of the genus Manta in 2009, when a second manta species (Manta alfredi) was resurrected based on morphological and meristic data, all available records in Fijian literature were recorded as Manta birostris. Subsequently, documented sightings were recorded as M. alfredi. Another reclassification of the genus Manta was undertaken in 2018 when both manta ray species (Manta alfredi, Manta birostris) were moved to Mobula based on phylogenetic analysis. Here, we present the first unequivocal evidence of oceanic manta ray (Mobula birostris) occurrence in Fijian waters. In November 2018, two individuals were sighted foraging in Laucala Bay, a large lagoon adjacent to Suva, the capital city of Fiji. Subsequently, three more individuals were sighted in December 2018, two individuals in July 2020, at least six individuals were observed in November 2021, and eight individuals in May/June 2022, all foraging in the same geographical area. Unique ventral identification patterns could be obtained for nine individuals, and all nine individuals have been re-sighted since first identification, with one individual being documented in 2018, 2020, 2021 and 2022. Two additional individuals were recorded in the Yasawa Island Group in the west of Fiji while passing through and foraging in a channel between Drawaqa and Naviti Island in April and September 2020. We provide photographic identification of ten M. birostris individuals from two sites and discuss our findings in the context of local environmental parameters and other recorded sightings in the South Pacific region. In light of the global extinction risk of M. birostris and the recent reclassification from Vulnerable to Endangered on the Red List of Threatened Species, the expansion of their known distribution range to Fijian waters and the recurrence of individuals over consecutive years in the same location adds valuable information for the development of effective and data-driven conservation strategies.

Ventral and lateral spot patterns differentiation between three smooth newt species (Amphibia: Salamandridae: Lissotriton)

The location, shape and area of dark spots on the belly, throat and sides of the body of three closely related species of smooth newts (Lissotriton kosswigi, L. schmidtleri and L. vulgaris) were analysed. Differences were found between species and sexes in the location and shape of dark spots on the belly, throat and lateral surfaces of the body. Discriminant analysis of these spot characteristics allows to identificate of males of all three species with a high degree of confidence (85–91%). In females, only L. vulgaris was correctly distinguished from the other two species (accuracy 81–94%). Anatolian and Thracian populations of L. schmidtleri have very similar patterns of dark spots, which confirm their conspecificity. The differences in the location and size of dark spots make possible successful identification of the species during field research and study of museum specimens. The developed method could be useful for comparative studies of other animal species which have spotted camouflage or aposematic colouration.