Dorsal Pigmentation Patterns Research Articles

Ontogenetic Changes in Pigmentation Pattern in Mesanthura miyakoensis (Crustacea: Isopoda: Anthuridae).

Species in the anthurid isopod genus Mesanthura have specific, dorsal dark pigmentation patterning on the body. Though Mesanthura species have traditionally been distinguished mainly by differences in the dorsal pigmentation pattern in females, the stability of the pigmentation pattern within species had not been investigated, and information was lacking on ontogenetic variation in the pattern. Our study showed the following for M. miyakoensis. (1) Mancae begin to show dorsal pigmentation in the marsupium roughly 9 days before their release. (2) The pigmentation pattern in the first-instar mancae (first free-living stage) differs from that in later instars. (3) The pigmentation pattern in females is discrete and stable from putative second-instar mancae through females lacking oostegites, and distorted but recognizable in ovigerious females. (4) The pattern in males is different from and less discrete than that in females; it remains similar through the molt from subadult to adult male but changes markedly with age, leading to heavy pigmentation of the body. (5) The pigmentation pattern in mancae and females remains stable and observable after storage in ethanol for at least 13.7 months. Our results suggest that comparisons of pigmentation pattern across species in Mesanthura taxonomy should be restricted to females in the post-manca or later stages.

First record of a potentially introduced leech, Helobdella aff. robusta Shankland, Bissen & Weisblat, 1992 (Hirudinea, Glossiphoniidae), in Japan

Helobdella aff. robusta Shankland, Bissen & Weisblat, 1992 is recorded for the first time from Japan. The haplotype of the cytochrome c oxidase subunit I (COI) gene sequence of a specimen from Japan is identical to that of one collected in California, USA. The dorsal pigmentation pattern of the Japanese specimens is different from that of H. robusta inhabiting North America, but nonetheless, most of their morphological characteristics are con-sistent with the diagnostic features of this species. This species is considered to be of New World origin, and the Japanese population was likely established from a recent introduction.

Revision of Chloeia Savigny in Lamarck, 1818 (Annelida, Amphinomidae)

Chloeia Savigny in Lamarck, 1818 is the largest genus in the Amphinomidae by including more species than other genera. Members of Chloeia species thrive in mixed substrates or sediments, mostly in tropical waters, and rarely reach deep water, or cold-temperate environments. A recent revision dealt with the species from tropical American seas and resulted in the redescription of five species, and the description of two other new ones. The objective for this additional contribution was to revise type and non-type specimens deposited in 12 of the largest world collections, and by applying a slightly modified approach from the precedent revision. Species were grouped herein after the type of branchiae, the first chaetiger with branchiae, and the dorsal pigmentation pattern. The results include the redescription of 16 species, with C. flava (Pallas, 1766) and C. fusca M'Intosh, 1885 being restricted, and three others reinstated: C. incerta de Quatrefages, 1866; C. fucata de Quatrefages, 1866, and C. pulchella Baird, 1868; 10 species are regarded as indeterminable: C. ancora Frickhinger, 1916; C. bengalensis Kinberg, 1867; C. candida Kinberg, 1857; C. egena Grube, 1855; C. furcigera de Quatrefages, 1866; C. macleayi Haswell, 1879; C. malaica Kinberg, 1867; C. nuda de Quatrefages, 1866; C. quatrefagesii Baird, 1868; and C. rupestris Risso, 1826. Further, 10 recently described species are being diagnosed and compared to their most similar species, but not redescribed; and 17 species are newly described: C. amoureuxi sp. n. from Madagascar, C. bemisae sp. n. from The Philippines, C. boucheti sp. n. from Indonesia, C. fauveli sp. n. from the Bay of Bengal, C. fiegei sp. n. from the Red Sea, C. gesae sp. n. from the Northeastern Atlantic, C. gilleti sp. n. from Western Africa, C. hutchingsae sp. n. from Australia, C. keablei sp. n. from Papua New Guinea, C. mezianei sp. n. from Western Africa, C. murrayae sp. n. from Australia, C. piotrowskiae sp. n. from The Philippines, C. poupini sp. n. from the French Polynesia, C. richeri sp. n. from New Caledonia, C. slapcisnkyi sp. n. from The Philippines, C wangi sp. n. from The Philippines, and C. zibrowii sp. n. from the French Polynesia. Keys to all archinomin genera and to all species of Chloeia are also included.

Morphological, molecular and phylogenetic characterization of a new Chloeia (Annelida: Amphinomidae) from a pockmark field

Pockmarks are crater-like depressions in seabed sediments commonly found along continental margins and generally associated with episodic fluid seepage. In this study, we describe a new species of Chloeia (Amphinomidae) gathered from a pockmark field, located off the southeastern Brazilian continental margin (~750 m depth), SW Atlantic. The complete mitochondrial genome is given, together with a multi-gene phylogenetic analysis including our new species and other amphinomids. The new species is similar to Chloeia bimaculata, C. violacea and C. kudenovi in having the longest neuropodial cirri on the second chaetiger. Chloeia pocicola sp. nov. differs from these congeners mainly by the combination of its dorsal pigmentation pattern, eyes, notopodial cirri, and neuropodial chaetae. Our phylogenetic hypothesis suggests Chloeia as a sister group of Archinome, which departs from previous studies, that instead suggests the clade Chloeia-Notopygos. This study increases our knowledge on the biodiversity of deep-sea pockmark environments, and contribute to the systematics of Amphinomidae, which is generally well represented in shallow waters, but also occurs in deep waters, including chemosynthetic environments.

A new species of Zeuxo (Crustacea: Peracarida: Tanaidacea) from Japan, with remarks on carapace pigmentation as a potentially useful taxonomic character

ABSTRACT We describe Zeuxo ezoensis sp. nov. from Hokkaido, Japan. This species closely resembles Z. phytalensis, Z. shitipingensis and Z. turkensis in having the pleopodal endopod with one inner plumose seta, maxillipedal palp article 4 with one outer simple seta, the left mandible with a wide, denticulate lacinia mobilis and one bifurcate accessory seta, and the right mandible with a peg-like lacinia mobilis and two accessory setae. It differs from them in having (1) antennal article 6 longer than wide, (2) the distal region of the maxillipedal endite with four spiniform setae and two circumplumose setae, (3) maxillipedal palp article 2 with one outer simple seta, (4) the chelipedal carpus with three or four dorsodistal simple setae, (5) the chelipedal dactylus with one inner simple seta, (6) the pereopod-1 basis with one or two ventrodistal simple setae, (7) the pereopod-1 carpus with one ventrodistal simple seta, and (8) the uropod with four or five articles (basal article plus three or four ramus articles). Partial nucleotide sequences for the cytochrome c oxidase subunit I (COI) gene (655 nt) from Z. ezoensis specimens from four localities in Hokkaido showed Kimura 2-parameter (K2P) divergences of 0–0.5% and 0.6–1.5% within and between populations, respectively. Based on the COI data, we examined the phylogenetic position of Z. ezoensis within Zeuxo. Six specimens used for morphological observations and 10 specimens used for COI sequencing showed a similar dorsal pigmentation pattern on carapace. We briefly discuss the validity of using this pattern as a diagnostic character in Zeuxo taxonomy. http://zoobank.org/urn:lsid:zoobank.org:pub:6CB565DB-DAFF-41EF-A06D-EAAE2F619C31

Early development of twoCapitellaspecies (Annelida: Capitellidae) from the Gulf of Mexico

AbstractEarly development of the polychaetesCapitellasp. TF from Tampa, Florida andCapitellasp. TV from Tamiahua Lagoon, Veracruz was studied under laboratory conditions. Our observations indicate that hermaphrodites occur inCapitellasp. TF, but not inCapitellasp. TV. Length and volume of larvae and early juveniles were measured daily. Both species appear to have lecithotrophic development. Sizes and duration of the developmental stages varied widely, as in most known species ofCapitella. Characteristic features ofCapitellasp. TF include very small hermaphrodites with a distinct dorsal pigmentation pattern and characteristically shaped brood tubes with a centrally thickened region. Embryos forced to abandon the brood did not survive more than 3 days, and handling the brood produced alterations in timing. Ciliated metatrochophores fromCapitellasp. TV survived inside the brood without the female for at least 14 days and some larvae hatched and died during settling. Some of these larvae were abnormal, with two rounded protuberances in the two ends. Mortality was high. Fungi and protozoans appeared in the dishes and probably partially induced the production of thicker mucus in the brood tubes, delay in metamorphosis, juvenile mortality, worm length and failure in coupling. Size and duration of the developmental stages were distinctly different from the other putative lecithotrophic species of the complex. These differences and other characteristics of each species discard the possibility that they belong to a previously described species. Our results are applicable to future ecological, morphological and molecular studies of each species, habitat and phylogenetics.

An assessment of sperm whale occurrence and social structure off São Miguel Island, Azores using fluke and dorsal identification photographs

AbstractFemale and immature sperm whales form stable social units in tropical to subtropical waters. One such area is the Azores archipelago, where details of their year‐round occurrence and social organization are not well known. We used year‐round sightings data collected from whale watching vessels to assess sperm whale occurrence and social structure off São Miguel Island, Azores from 2010 to 2017. Individuals were photo‐identified by their flukes (n = 393) and dorsal pigmentation marks were examined to explore their use in assisting with reidentifications. Of all cataloged whales, 78.8% were sufficiently distinctive to be reidentified from dorsal pigmentation patterns. Associations between individuals were analyzed to determine social structure and delineate social units. We identified 12 units comprising 2–13 members that had stable, and perhaps preferred associations for periods up to the eight years of the study. Preferences between some pairs of units may exist, but more research is required to better understand dynamics within and between units. This local scale study is an important contributor to our knowledge of geographic variation on a global scale. We recommend making use of all available information from the entire archipelago, to further increase our understanding of sperm social organization in the Azores.

DNA metabarcoding to assess diet partitioning and feeding strategies in generalist vertebrate predators: a case study on three syntopic lacertid lizards from Morocco

Abstract DNA metabarcoding is a fast and simple alternative to traditional microscopy methods, which have been the main tool for identification of prey in dietary studies of lizards. In this study, we applied a metabarcoding approach based on COI and 16S rRNA amplicons to assess diet partitioning and feeding strategies in three syntopic lizards from Taza, Morocco: Scelarcis perspicillata chabanaudi, Scelarcis perspicillata pellegrini and Podarcis vaucheri. In order to avoid competition, these lizards are expected to consume different prey species because they occupy distinct trophic niches, use different foraging strategies and express different dorsal pigmentation patterns. Given the spotted pattern of S. p. chabanaudi, we hypothesize a sit-and-wait foraging strategy with a less diverse diet and a higher consumption of mobile prey relative to the striped S. p. pellegrini and P. vaucheri which, as potential active foragers, are expected to have a higher diet diversity. Previous diet assessments using microscopy on faecal remains seem to contradict these expectations. Our results show that, as expected, the diet of S. p. chabanaudi is less diverse than the diet of S. p. pellegrini. Regarding P. vaucheri, our dietary data are consistent with the hypothesis that this species behaves as an active forager, owing to its high niche overlap with S. p. pellegrini. Advantages and limitations of molecular barcoding compared with the microscopy approach to the analysis of lizard diets are discussed.

Four new species of the genus Paraustrorhynchus (Rhabdocoela: Kalyptorhynchia: Polycystididae).

Four new species of Paraustrorhynchus (Rhabdocoela: Kalyptorhynchia: Polycystididae) are described: two from Southern China (P. shenda n. sp., P. sinensis n. sp.), one from New Caledonia (P. isoldeae n. sp.), and one from India (P. smeetsae n. sp.). All four species show a typical dark blue dorsal pigmentation pattern, which is unique to the genus. This pigment forms a broad longitudinal line in P. shenda n. sp. and P. sinensis n. sp., shows an additional transverse band at the level of the pharynx in P. smeetsae n. sp. and forms a Y-shaped pattern in P. isoldeae n. sp. The four species can also be distinguished from each other and their congeners by the detailed morphology of the hard parts of the male system, which in all cases consists of an L-shaped (P. shenda n. sp., P. isoldeae n. sp) or slightly-curved (P. smeetsae n. sp., P. sinensis n. sp.) prostate stylet type II and a prostate stylet type III, which consists of three plates: a basal plate from which two longer plates depart, each with a distal serrated rim. A phylogenetic analysis based on 18S and 28S-rDNA data indicates that Paraustrorhynchus is a monophyletic taxon within Polycystidinae, with Alcha evelinae as the sister group.

Movement correlates of lizards’ dorsal pigmentation patterns

Summary Understanding the ecological function of an animal's pigmentation pattern is an intriguing research challenge. We used quantitative information on lizard foraging behaviour to search for movement correlates of patterns across taxa. We hypothesized that noticeable longitudinal stripes that enhance escape by motion dazzle are advantageous for mobile foragers that are highly detectable against the stationary background. Cryptic pigmentation patterns are beneficial for less‐mobile foragers that rely on camouflage to reduce predation. Using an extensive literature survey and phylogenetically controlled analyses, we found that striped lizards were substantially more mobile than lizards with cryptic patterns. The percentage of time spent moving was the major behavioural index responsible for this difference. We provide empirical support for the hypothesized association between lizard dorsal pigmentation patterns and foraging behaviour. Our simple yet comprehensive explanation may be relevant to many other taxa that present variation in body pigmentation patterns.

Dorsal body pigmentation and sexual dimorphism in the marbled salamander (Ambystoma opacum)

Marbled salamanders (Ambystoma opacum) have individually variable dorsal pigmentation patterns. But it is unclear whether or not dorsal pigmentation is associated with variables such as body size and sex. In this study, we test the hypothesis that the body size variables and sex are important predictors of the coverage of dorsal body white pigmentation in adult marbled salamanders. We evaluate the degree of sexual dimorphism in several body traits, including the dorsal body white pigmentation, using univariate and multivariate methods, and analyze the sex-related difference in pigmentation asymmetry. The General Linear Model (GLM) predicts a significant main effect of sex and a significant interaction between sex and dorsal body area (DBA), influencing the coverage of dorsal body white pigmentation. The interaction effect is greater in males than in females. We show significant sex-related differences in body size and shape. Eight morphometric traits reveal female-biased sexual size dimorphism, while males display a greater coverage of dorsal white pigmentation than females. Prominent female characteristics, compared to males, include a significantly heavier and longer body with a wider trunk, head, neck, shoulder and waist. These sex-specific differences suggest selection for a larger body size in females because of increased maternal reproductive success associated with larger body size. Additionally, females display greater pigmentation asymmetry than males, suggesting a significant sex-related disparity in asymmetric pigmentation. Potential ecological and developmental implications of the observed dimorphism are discussed. To our knowledge, this is the first study demonstrating an association of dorsal white pigmentation with dorsal body area and sex, including a significantly disproportionate pigmentation asymmetry between sexes, in adult marbled salamanders.

Review of the Halieutichthys aculeatus species complex (Lophiiformes: Ogcocephalidae), with descriptions of two new species

The Halieutichthys aculeatus species complex is reviewed. Members of this clade are distinguished by the presence of tubercles on the tail and a reticulate dorsal pigmentation pattern. Three species are recognized, including two species new to science. A neotype is chosen for H. aculeatus. Halieutichthys bispinosus n. sp. is characterized by having relatively strong tubercles on the dorsal surface, a row of tubercles almost always present dorsal to the orbit, both sphenotic tubercles well developed and sharp, trifid principal tubercles on the disk margin with anterior spinelet enlarged, dense arrangement of tubercles on the tail and a comparatively large adult body size. Halieutichthys intermedius n. sp. can be distinguished from congeners by having both sphenotic tubercles strongly reduced, the tubercles almost always absent dorsal to the orbit, principal tubercles on the disk margin uniformly short and blunt tubercles, with all spinelets generally reduced.

Locomotion and antipredator behaviour in three species of semi-aquatic snakes

For temperate-zone ectotherms, a potential cost of an aquatic lifestyle may be impaired locomotor performance, due to rapid cooling of the body when in cold water. Contrary to the hypothesis that more-aquatic species should be better adapted for locomotion at low temperatures, the decline in swimming performance with temperature was similar for three species of snakes (the northern water snake (Nerodia sipedon), eastern ribbon snake (Thamnophis sauritus) and common garter snake (Thamnophis sirtalis)) that varied in their association with aquatic habitats. The effect of temperature on antipredator behaviour was also similar for the three species; at lower body temperatures, snakes relied more on alternative defensive behaviours. However, antipredator behaviour was used less by water snakes than by garter and ribbon snakes. Except for the smallest individuals, all snakes crawled more slowly than they swam, and the difference in performance was greatest for the largest snakes. When crawling, all three species relied more on alternative defensive behaviours than when swimming. In the field, water snakes fled at greater distances from human "predators" than did garter and ribbon snakes, which tended to rely on crypsis. The greater dependence on flight as the primary antipredator behaviour by water snakes, and on other tactics such as crypsis by garter and ribbon snakes, does not conform to the generalization that a species' antipredator behaviour is related to its characteristic dorsal pigmentation pattern. Species differences in antipredator behaviour appear to be more strongly related to habitat use.

Life History of the Spotfin Killifish, Fundulus luciae (Pisces: Cyprinodontidae), in Fox Creek Marsh, Virginia

Fundulus luciae was collected for a year at Fox Creek Marsh and, occasionally, at other salt marshes along the York River, Virginia. It occurred in high intertidal areas in brackish, sometimes oxygen deficient shallow ditches, mudholes and tidal rivulets located in stands ofSpartina alterniflora. Preserved specimens were examined to determine the reproductive season, fecundity, diet and associated metazoan parasites of the species. Developing ova were present from mid-April to mid-August and exhibited a broad size range; the number of large ova (>1.6 mm diameter) never exceeded 16 per female. Stomach contents consisted mainly of detritus, diatoms, ostracods, dipterans and copepods. All major metazoan parasite groups except Cestoda were represented onF. luciae; Monogenea were most numerous, with 57.2% incidence. Eggs and larvae were described. Preserved larvae ofF. luciae were distinguished from those ofF. heteroclitus by their dorsal pigmentation pattern. It was concluded thatF. luciae, a purportedly rare species, is not rare, but probably restricted to high intertidal salt marshes where it may have been previously overlooked.

The Dorsal Pigmentation Pattern of Snakes as an Antipredator Strategy: A Multivariate Approach

Each species of the snake fauna of North America north of Mexico was qualitatively scored into one of five dorsal pattern classes and according to 16 behavioral-ecological variables that express the degree of exposure to visually oriented predators and the characteristic response to threatened predation. Multiple discriminant analysis was employed to identify the variables that best distinguish between the pattern types. These most important variables were, in general, behavioral as opposed to habitat variables. Irregularly banded and blotched-spotted patterns are associated with an antipredator strategy of defense rather than flight, and these patterns likely function disruptively to minimize initial detection by predators. Striped and unicolored-speckled patterns are associated with antipredator strategies emphasizing flight more than defense. The advantages of these patterns for a strategy of flight probably lie in their elevation of the threshold velocity for detection of movement and in their reduction of apparent velocity, because these visual effects retard the forward shift of predator visual focus necessary to keep the fleeing snake in sight. On the behavioral-ecological axes, the regularly banded pattern is generally intermediate between the antipredator strategies of defense and flight, and it may combine the advantages of disruptive coloration with those of a uniform pattern through the phenomenon of flicker fusion of the successively identical bands. As predicted, if flicker fusion is an adaptive function of the regularly banded pattern, interspecific variation in band number is negatively correlated with a morphological index of escape speed, positively correlated with body size, and curvilinearly related to (though nonsignificantly) the light-dark ratio of the band cycle. Furthermore, intraindividual variation in band packing is in the direction predicted by speed differentials between middle and rear portions of the body. The multiple discriminant analysis was almost three times as successful in classifying taxa to pattern type as would be expected by chance.