Dorsal Blotches Research Articles

A new species of pit-viper from the Ayeyarwady and Yangon regions in Myanmar (Viperidae, Trimeresurus).

In a genomic study by Chan and colleagues, pit-vipers of the Trimeresuruserythrurus-purpureomaculatus complex from the Ayeyarwady and Yangon regions in Myanmar were demonstrated to be a distinct species based on robust population genetic and species delimitation analyses. Here, we provide morphological characterizations and a formal description of those populations as a new species. The new species, Trimeresurusayeyarwadyensissp. nov., is most closely related to T.erythrurus and T.purpureomaculatus and shares morphological characteristics with both of those species. Some specimens of T.ayeyarwadyensissp. nov. have green dorsal coloration and no distinct dorsal blotches (a trait shared with T.erythrurus but not T.purpureomaculatus), while others have dark dorsal blotches (a trait shared with T.purpureomaculatus but not T.erythrurus). The distinct evolutionary trajectory of the new species, coupled with the lack of obvious morphological differentiation, represents a classic example of the cryptic nature of species commonly found in the Trimeresurus group of Asian pit-vipers and underscores the need for data-rich analyses to verify species' boundaries more broadly within this genus.

Conspicuous coloration of toxin-resistant predators implicates additional trophic interactions in a predator-prey arms race.

Antagonistic coevolution between natural enemies can produce highly exaggerated traits, such as prey toxins and predator resistance. This reciprocal process of adaptation and counter-adaptation may also open doors to other evolutionary novelties not directly involved in the phenotypic interface of coevolution. We tested the hypothesis that predator-prey coevolution coincided with the evolution of conspicuous coloration on resistant predators that retain prey toxins. In western North America, common garter snakes (Thamnophis sirtalis) have evolved extreme resistance to tetrodotoxin (TTX) in the coevolutionary arms race with their deadly prey, Pacific newts (Taricha spp.). TTX-resistant snakes can retain large amounts of ingested TTX, which could serve as a deterrent against the snakes' own predators if TTX toxicity and resistance are coupled with a conspicuous warning signal. We evaluated whether arms race escalation covaries with bright red coloration in snake populations across the geographic mosaic of coevolution. Snake colour variation departs from the neutral expectations of population genetic structure and covaries with escalating clines of newt TTX and snake resistance at two coevolutionary hotspots. In the Pacific Northwest, bright red coloration fits an expected pattern of an aposematic warning to avian predators: TTX-resistant snakes that consume highly toxic newts also have relatively large, reddish-orange dorsal blotches. Snake coloration also seems to have evolved with the arms race in California, but overall patterns are less intuitively consistent with aposematism. These results suggest that interactions with additional trophic levels can generate novel traits as a cascading consequence of arms race coevolution across the geographic mosaic.

A new species of the genus Oligodon Fitzinger, 1826 (Squamata: Colubridae) from Langbian Plateau, Vietnam

We describe a new species of kukri snake from Da Lat City and its vicinity in Lam Dong Province, southern Vietnam on the basis of morphological characters of four specimens, including two males and two females. Oligodon tuani sp. nov. differs from other congeners by a combination of the following characters: large size in adults (TL ≤ 888 mm); 19 dorsal scale rows at midbody; ventrals 173-179 in males and 187-193 in females; subcaudals 58 or 59 in males and 44 or 45 in females; presubocular present; 8 supralabials, fourth and fifth entering orbit; cloacal plate undivided; 10 maxillary teeth, posterior three enlarged; vertebral stripe present; temporal streak present but faint and interrupted; long and deeply forked hemipenes, extending to 25th subcaudal, without spines and papillae; and 13-15+3-4 dorsal blotches.

A New Burrowing Frog of the Odontophrynus americanus Species Group (Anura, Odontophrynidae) from Subtropical Regions of Argentina, Brazil, and Paraguay

A new species of frog of the genus Odontophrynus is described from grassland of the subtropical regions of Argentina, Brazil, and Paraguay based on morphological, osteological, bioacoustical, cytogenetic, and molecular evidence. The new species is characterized by having medium size; rostral and eye-nostril glandular warts well developed; several long glandular ridges, longitudinally oriented, on dorsum; several medium-sized, nearly rounded, dark-brown dorsal blotches; light mid-dorsal stripe continuous and well defined or restricted to the head and the urostyle regions; and mid-dorsal stripe, interorbital, and dorsolateral bands with a moderately whitish highlight, light brown, or reddish coloration. Additionally, the new species has a skull with nasals slightly separated both from each other and frontoparietals, and frontoparietal fontanelle not exposed. The advertisement call consists of a single multipulsed note with a dominant frequency of 820–1,121 Hz and a pulse rate of 99.3–140.7 pulses/s. The chromosomal complement is diploid with 2N = 2X = 22 chromosomes and nucleolar organizer regions on the interstitial regions of the short arm of chromosome pair 4. The phylogenetic analysis allowed us to recover the new species belonging to the O. americanus species group with genetic distances from its congeners ranging from 2.11 to 4.82% in a partial sequence of 16S ribosomal RNA gene. The new species is geographically isolated from the other currently known diploid species of the group, but in some localities is found in sympatry or syntopy with the tetraploid O. americanus.

A New Species of Snail-Eating Snake, Dipsas Cope, 1860 (Serpentes: Colubridae: Dipsadinae), from the Atlantic Forest of Brazil

We describe a new species of snail-eating snake from two localities within the Atlantic Forest of the states of Bahia and Minas Gerais, Brazil. The new species differs remarkably from all congeners by its dorsal pattern consisting of sharply bordered triangles resembling the pattern of sympatric pitvipers, more precisely Bothrops jararaca and B. pirajai. Parameters of external morphology of the new species resemble those of the Dipsas incerta species group. Its scalation, body/head shape, and color pattern are most similar to D. alternans, a species known to occur 360 km farther south, across the Rio Doce river. The new species differs from D. alternans by exhibiting triangular dorsal blotches and a higher number of pileus blotches, by the distribution of ventral spots and morphology of the supratemporal and premaxillae, as well as in hemipenial morphology. We also provide comparisons of the new species with all sympatric and/or parapatric congeners. The finding of a new snake species in the Atlantic rainforest of southern Bahia and adjacent Minas Gerais is particularly surprising as this region is easily accessible and represents a well-sampled area regarding herpetological surveys in the last decades.

A new subspecies of African fire salamander Salamandra algira (Urodela, Salamandridae) from the Middle Atlas Mountains, Morocco

A new subspecies within the Salamandra algira species complex from north-western Africa is described. Previous molecular analysis showed that the populations of S. algira splendens from north-western Morocco consisted of two well supported clades: clade 1 distributed in the Rif Mountains, from Chefchaouen (type locality) to Al Hoceima, and clade 2, located southern from clade 1 being isolated in the northern and central Middle Atlas Mountains. Clade 2 is herein described as a distinct subspecies: Salamandra algira atlanticassp. nov. based on morphological data, allopatric range and molecular divergence. This new subspecies shows an uncorrected pairwise distance of 0.0265 from clade 1 based on cytochrome b DNA sequences. Salamandra algira atlanticassp. nov. is a slender and large sized salamander with a highly variable colouration pattern. It can be distinguished from S. algira splendens by the greater proportion of coral red in the background colouration, being the only known subspecies of S. algira in which coral red can exceed the proportion of black. Variable number (0–5) of yellow to golden yellow dorsal blotches, but usually in lower numbers than the nominotypical subspecies. Salamandra algira atlanticassp. nov. inhabits subhumid to humid forests and karstic systems at mid to high elevations. We briefly discuss the phylogenetic and taxonomic issues among the genus Salamandra which encompasses more valid species than currently recognised.

Polyclad fauna of Agatti Island, Lakshadweep, India: new records and description of two new species.

The present paper deals with the first study of polyclad fauna from Agatti Island, Lakshadweep. Through this study, Pseudobiceors apricus, Pseudobiceros hymanae and Pseudoceros bolool are recorded for the first time from Lakshadweep waters while Pseudoceros bicolor is recorded for the first time from Indian waters. Description of two new species, Pseudoceros agattiensis sp. nov. and Pseuodoceros stellans sp. nov. is also provided with good quality photographs of external and internal details. Pseudoceros agattiensis sp. nov. is characterized by a brown to black background colour, with minute white spots, marginal band thick and black with minute white spots present at very edge of the margin, three dorsal longitudinal white bands, out of which, two are laterally branched. Pseudoceros stellans sp. nov. displays a brown background colour with a black marginal band and completely covered with lighter microdots and a unique pattern of white dorsal blotches. This study adds to the knowledge of Indian polyclads, which are still an understudied group from Indian waters.

Cobitis Fusunae, A New Spined Loach Species (Teleostei: Cobitidae) from the Sultan Marsh, (Kayseri, Turkey)

Cobitis fusunae is a new species described from the Sultan Marshes, Kayseri Province, Turkey. This species differs from the congener species of Cental Anatolian Basins by the combination of the following characters (none unique to the species): No black spot on caudal-fin base, having Z4 with dark-black stripe, pigmentation below Z4, merged Z1-Z3 postdorsally, 12-18 small mid dorsal blotches and one lamina circularis in males, two fixed, diagnostic nucleotide substitutions in the mtDNA COI barcode region, and a minimum K2P genetic distance of 5.4%.

Una nueva especie de serpiente venenosa terrestre del género Porthidium (Serpentes: Viperidae), del Suroeste de Costa Rica

A new species of terrestrial pitviper, Porthidium volcanicum, is described from low elevations near Buenos Aires, in the Valle del General, southwestem Puntarenas Province, Costa Rica. It is the eighth known member of the hognosed pitviper genus. Distinctive characters are the color pattem, high number of dorsal blotches and ventral scales, together with the presence of a single canthal scale. These morphological data indicate close affinities with Porthidium lansbergii

A New Species ofCharacidiumReinhardt (Characiformes, Crenuchidae) with a Distinctively Dimorphic Male

We herein describe Characidium satoi, new species, only known from its type locality at Rio Curral das Eguas, a small tributary of Rio Abaete, in the Rio Sao Francisco basin, Brazil. It can be distinguished from its congeners by the following characteristics: area between the pelvic fin and the origin of anal fin moderate to strongly convex in lateral view; presence of irregular and discontinuous bars, forming dorsal blotches separated from ventral V-, W-, or diamond-shaped marks; and the first anal-fin radials inserted between the fifth and sixth caudal vertebrae. The juveniles and mature females of Characidium satoi, new species, have smooth fin rays, while mature males have hooks on pelvic and, in some specimens, pectoral and dorsal fins. Moreover, females and immature males have irregular bars on dorsum and fuzzy vertical bars on body; during the breeding season, males develop uniformly darker pigmentation on body and head, lacking any distinctive vertical bar on body. This seasonal color dimorphism i...

Assessing the heritability of dorsal pattern shape in Vipera latastei

The ecological advantages of dorsal pattern in European vipers, having aposematic/cryptic roles and/or enhancing thermoregulation among others, suggest that dorsal colouration is adaptive and submitted to selection. We have assessed its heritability by comparing the number of dorsal blotches (a quantitative measure of the dorsal-pattern shape) between 23 Vipera latastei females and their brood across the Iberian Peninsula. We found a high correlation () between both female and brood blotch counts suggesting a high heritability for this character. Previous studies reported that the number of dorsal blotches shows geographic variation across the Iberian Peninsula and supported the adaptive character of dorsal pattern shape in V. latastei. This is a new contribution to understand the mechanisms involved in dorsal pattern variation in European vipers.

New species of lizard from the magellanicus clade of the Liolaemus lineomaculatus section (Squamata: Iguania: Liolaemidae) from southern Patagonia

A new species of the Liolaemus lineomaculatus section is described from southwestern Santa Cruz Province, Argentina. The new species is a member of the monotypic magellanicus clade; morphological, molecular and geographical data are sufficient to diagnose this new species as distinct form from L. magellanicus. The new species differs from L. magellanicus in having higher number of midbody, dorsal and ventral scales, and higher number of infradigital third finger and fourth toe lamellae. The new species also differs in having smaller dorsal blotches on the hindlimbs and a more clearly defined vertebral line, fewer precloacal pores and reduced dorsal scale mucronation, compared to L. magellanicus. Liolaemus caparensis sp. nov. is the second species described for the magellanicus group, and is geographically isolated from L. magellanicus on the Campo Las Piedras Plateau, where it is sympatric with other endemic species of the L. lineomaculatus section.

A new species of Dipsas Laurenti from the Atlantic Forest of Brazil (Serpentes: Dipsadidae)

Dipsas sazimai sp. nov. is described from the Atlantic Forest of Brazil. The new species is distinguished from all congeners by showing anterior portion of body with rounded dorsal blotches wider than interblotches; median and posterior portion of body with blotches higher than long and narrower than interblotches; posterior body blotches lighter than anterior blotches; posterior blotches with conspicuous white edge in paraventral region; tiny and vertically oriented streaks in the interblotches from the posterior half of body; 187–209 ventral scales; 107–129 subcaudal scales; and the first blotch not reaching the rictus. Based on characters of external morphology and color pattern we suggest the new species is related to taxa of the recently proposed Dipsas incerta species group.

Phenotypic differences in a cryptic predator: Factors influencing morphological variation in the terciopelo Bothrops asper (Garman, 1884; Serpentes: Viperidae)

The terciopelo Bothrops asper, is a cryptic lancehead pitviper widely distributed in humid environments of Middle America and the north-western portion of South America. Throughout its extensive distribution range, the terciopelo exhibits great morphological variation in external characters, a situation that has complicated its proper separation from other related species. In this paper, we analyzed the phenotypic variation of B. asper based in a sample of 514 specimens from nine distinct physiographic regions. Univariate and multivariate analyses demonstrated great phenotypic differentiation among most pre-established groups, and the pattern is fairly congruent between sexes. However, no correspondence was observed between morphological variation and molecular divergence, inferred from mDNA sequences, between individuals representing the physiographical regions under study. Geographic variation in the number of interrictals, ventral scales, subcaudal scales and dorsal blotches was positively correlated with latitude and number of dry months, but inversely related with precipitation. However, other variables do not exhibit such an effect. The observed relationships between scale counts and environmental variables are explained in terms of selective pressures to improve water balance along the distributional range of the species.

A rare alpine skink Oligosoma pikitanga n. sp. (Reptilia: Scincidae) from Llawrenny Peaks, Fiordland, New Zealand

A new species of alpine skink, Oligosoma pikitanga, is described from the Llawrenny Peaks, Fiordland, New Zealand. This species is diagnosed on the basis of strong morphological, ecological, and genetic differentiation from the following relatives O. acrinasum, O. infrapunctatum, O. otagense, O. taumakae and O. waimatense. The species is characterized by a shiny black base colour with bright green dorsal blotches, lateral pinkish spots and a vivid orange belly. It appears this new taxon is extremely rare, and at enhanced risk from introduced mammalian predators.

Studies on Anacondas III. A Reappraisal of Eunectes beniensis Dirksen, 2002, from Bolivia, and a Key to the Species of the Genus Eunectes Wagler, 1830 (Serpentes: Boidae)

Eunectes beniensis Dirksen, 2002 is a recently discovered anaconda species from Beni Province, Bolivia. Based on morphological and molecular genetic evidence, E. beniensis is closer related to E. notaeus and E. deschauenseei than to E. murinus . The phylogenetic relationships within Eunectes are currently best described as: E. murinus [ E. beniensis ( E. deschauenseei , E. notaeus )]. E. beniensis is easily recognizable by its brown to olive-brownish ground color in combination with five head stripes and less than 100 large dark, solid dorsal blotches which always lack lighter centers. An identification key for the species of Eunectes is provided.

Ontogenetic Changes in the Coloration of the Northern Watersnake, Nerodia sipedon sipedon

Juvenile Nerodia sipedon sipedon possess a striking dorsal pattern, whereas adults often have a more uniform dorsal coloration. Past researchers have hypothesized that this color shift occurs through a darkening of the ground color, but this hypothesis has never been tested quantitatively. Analysis of digital images of the dorsum and venter of N. s. sipedon individuals of all sizes from islands in Lake Michigan indicated that as snakes increase in length, the dorsal ground color darkens, but the coloration of dorsal blotches and ventral pattern does not change. Potential costs and benefits of a change in dorsal coloration while ventral pattern remains relatively constant are discussed in relation to variation in size.

Molecular Analysis Supports Specific Status for Bufo pardalis and Bufo pantherinus

In South Africa, the endemic toad species Bufo pardalis, more commonly known as the leopard toad, was initially described by Hewitt (1935) from Kei Road in the Eastern Cape, as a subspecies of Bufo regularis, Bufo regularis pardalis. It is distributed in two allopatric populations: one that occurs in the extreme southwestern Cape including the Cape Peninsula, Cape Flats and forelands to Hermanus, and the other, larger population that occurs in the Eastern Cape Province from Cape St. Francis to the Kwazulu-Natal border. The smaller Western Cape population is threatened because of the increase in recent years of land development for housing on the peninsula, with corresponding habitat losses (M. I. Cherry, pers. obs.). Hewitt made a distinction between the western and eastern forms based on morphological differences including more brilliant coloration, larger dorsal blotches and broader parotid glands in western specimens. In 1964, Poynton raised Bufo pardalis to specific status but made no comment on Hewitt's distinction between western and eastern forms. Comparisons of laryngeal morphology by Lambiris (1994) provided additional support for species recognition of the two populations. Poynton and Lamibiris (1998) elevated the Western Cape form to specific status as Bufo pantherinus: B. pantherinus was found to have distinctive coloration and markings, as well as unique laryngeal and parotid gland morphology. Differences in call structure have not yet been investigated, but it is intriguing to speculate that the differences in the laryngeal morphology may be reflected by differences in the call structure.

Absence of Cold Acclimation Response in Gray Treefrogs, Hyla chrysoscelis and Hyla versicolor

The gray treefrog complex consists of two morphologically similar species, Hyla chrysoscelis and Hyla versicolor. These sibling species can be differentiated by genome size in the laboratory and by mating call in the field. Hyla chrysoscelis is diploid (2n = 24) with a mating call pulse rate of 36 pulses per second or higher, while H. versicolor is tetraploid (2n = 48) with a mating call pulse rate at or below 25 pulses per second depending upon temperature (Zweifel, 1970; Ralin and Selander, 1979). The overall distribution of the two species extends from northern Florida to southern Maine in the east and from central Texas to southern Manitoba in the west (Conant and Collins, 1991). Although the distribution of each species has not been accurately delineated, H. versicolor (the tetraploid species) occurs more frequently in the northern region of this range while H. chrysoscelis occurs primarily in the southern region (Ralin and Selander, 1979). Compensation of metabolic rate in response to lower temperatures (cold acclimation) allows organisms to survive and function under adverse thermal conditions (Rome et al., 1992). For example, Rieck et al. (1960) demonstrated that Rana pipiens held at 5 C had metabolic rates two times greater upon exposure to 10 C than specimens held at 25 C. Such a response allows for greater physiological efficiency at lower temperatures and improved cold tolerance. Previous research provided evidence that H. chrysoscelis (the diploid species) does not have the ability to acclimate to cold temperature (Blem et al., 1986). However, Bailey and Thye (1975), showed that polyploidy enabled gene duplication as well as gene divergence in function. In their study, tetraploid salmonid fish showed a modification in isoenzyme regulation for lactate dehydrogenase (LDH). As with amphibians (Enig et al., 1976; Tsugawa, 1976), a relationship appears to exist between acclimation ability and LDH concentrations in the killifish Fundulus heteroclitus (Crawford and Powers, 1989). The purpose of the current study was to determine if polyploidy imparts a similar physiological advantage to H. versicolor with respect to its thermal acclimation ability. Calling male H. versicolor and H. chrysoscelis were collected between 15 and 31 May 1994 from Hunterdon and Cape May Counties, New Jersey, respectively. The body masses of the frogs ranged from 5.6-10.2 g for H. versicolor (mean = 8.0 g, SE = 0.45, N = 10) and 6.0-7.8 g for H. chrysoscelis (mean = 6.9 g, SE = 0.21, N = 12). Species identification was verified by analyzing recordings of the mating calls (Zweifel, 1970). The two species were held in separate aquaria at a constant temperature (21 C) and fed live crickets 2 to 3 times a week until experimentation in November and December, 1994. Individual frogs were identified by dorsal blotches and/or thigh spots, body mass and snout to urostyle length. Metabolic rates were measured as the amount of

COLOR-PATTERN VARIATION IN LAKE ERIE WATER SNAKES: PREDICTION AND MEASUREMENT OF NATURAL SELECTION

A classic example of natural selection, that of color-pattern variation in Lake Erie island populations of water snakes, was reexamined to overcome shortcomings resulting from classification of snakes into discrete color-pattern categories and use of cross-sectional data. Four continuously varying color-pattern components (DB, the number of dorsal blotches; LB, the number of lateral blotches; ROWS, the height of lateral blotches measured in scale rows; and VEXT, the extent of ventral pigmentation) were analyzed. Patterns of natural selection were predicted from the relationship between color-pattern scores and independent measures of relative crypsis. Tests for natural selection were carried out using longitudinal data on neonate to juvenile-aged snakes and cross-sectional data on juvenile to adult-aged snakes. As predicted, the form of selection differed between younger and older age classes of snakes: selection resulted in a reduction in DB and LB among neonate and juvenile snakes but had little influence on color-pattern components in older snakes. The correspondence between observed patterns of natural selection and predictions based on the relationship between color-pattern scores and relative crypsis supports the hypothesis that differential predation by visual predators on younger age classes of snakes is the mechanism of selection. Gene flow from mainland populations or the initial lack of an allele necessary for reduced pattern may explain why selection has not resulted in greater differentiation between island and mainland populations.