Browsing by Author "Daly, John W."
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Item An arboreal poison frog (Dendrobates) from western Panama. American Museum novitates ; no. 2783(New York, N.Y. : American Museum of Natural History, 1984) Myers, Charles W.; Daly, John W.; Martínez, Víctor, herpetologist."Dendrobates arboreus, new species, is a small arboreal frog with a dorsal and ventral pattern of vivid yellow spots on a brown or black field. It is abundant at 1100-1300 m. above sea level on a low section of the continental divide in western Panama, where, in undisturbed cloud forest, virtually the entire population resdies high aboveground on trees laden with bromeliads and other epiphytes. A few specimens also come from a locality in the adjacent Caribbean lowlands. The pale-spotted color pattern of Dendrobates arboreus is similar to that of the enigmatic D. maculatus, also from western Panama, but these two species differ significantly in morphology and are not closely related. Dendrobates arboreus is assigned to the histrionicus species group, which includes two species occurring macrosympatrically with arboreus, D. speciosus (highlands) and D. pumilio (lowlands). The monophyly of the histrionicus group is indicated by very similar-sounding chirp calls - given as long trains of harsh notes that differ among species in rate of note repetition, note duration, and dominant frequency. New spectrographic analysis of pulse rates compels a restatement of Myers and Daly's original distinction between chirp calls and buzz calls, two important classes of dendrobatid vocalization. Courtship and egg laying of Dendrobates arboreus, and cannibalism of eggs by an adult female, were observed in captivity. There is no amplexus during mating, although typical cephalic amplexus (primitive within the Dendrobatidae) is retained in the behavioral repertory, possibly in an aggressive context. Courtship includes tactile signals by both sexes prior to their assuming a vent-to-vent position for egg laying and fertilization. An instance of mate piracy was observed when a second male successfully intruded at a late stage of courtship, bypassing the preliminary tactile signaling of the original pair. Defensive skin secretions of Dendrobates arboreus contained 14 piperidine alkaloids, including members of the pumiliotoxin-A class and its allopumiliotoxin-A subclass. Remaining alkaloids, including two new compounds, are left unclassified. Histrionicotoxins were not detected"--P. [1]-2.Item A dangerously toxic new frog (Phyllobates) used by Emberá Indians of western Colombia, with discussion of blowgun fabrication and dart poisoning. Bulletin of the AMNH ; v. 161, article 2(New York : American Museum of Natural History, 1978) Myers, Charles W.; Daly, John W.; Malkin, Borys."Phyllobates terribilis, a remarkably toxic new species of frog, is described from the vicinity of an Emberá Chocó settlement in lowland rain forest of Pacific coastal Colombia. It is the third frog definitely known to be used for poisoning darts; the other species are P. aurotaenia and P. bicolor. Toxicity of the skin secretions of Phyllobates, and frog-poisoned darts, is due primarily to batrachotoxin and homobatrachotoxin, steroidal alkaloids that are stronger than curare mixtures. Phyllobates terribilis produces relatively massive quantities of these compounds and is at least twentyfold more toxic than other poison-dart frogs. The new species is potentially dangerous to handle: One freshly caught frog may contain up to 1900 micrograms ... of toxins, only a fraction of which would be lethal to man if enough skin secretion came into contact with an open wound. A human lethal dose is indirectly judged as being somewhere in the range of 2-200 [micrograms], and the secretions also are irritating to porous skin and poisonous if ingested. Phyllobates terribilis attains a snout-vent length of about 47 mm., making it one of the largest species in its family (Dendrobatidae). It is readily distinguished from all other dendrobatids in that body and limbs are a uniform golden or pale metallic green color above and below, except that small juveniles have a primitive pattern of golden dorsolateral stripes on a black ground. The ontogenetic color change, tadpoles, and other aspects of the life history and behavior are described. A component of aggressive grappling behavior of this and some other dendrobatids is suggested as being homologous with dendrobatid cephalic amplexus, an instance of which is photographically documented for Dendrobates tricolor. The trill call of Phyllobates is the third class of dendrobatid vocalizations to be defined. At the type locality, Phyllobates terribilis occurs in populations of predominantly adult frogs that probably have relatively long (> 5 years) and secure lives; reproductive success or juvenile survivorship might be inversely correlated with population density. Emberá Indians are occasional predators, and the snake Leimadophis epinephelus is identified as a potential predator, at least of young frogs. This snake has an unusual capacity for tolerating a great chemical diversity of anuran skin secretions. Piperidine-based skin alkaloids provide a shared, uniquely derived character (synapomorphy), seeming to establish that frogs of the Dendrobates-Phyllobates complex share a monophyletic origin apart from a sister group (Colostethus). But, in the Phyllobates bicolor group, primitive piperidine alkaloids have been largely replaced by a more effective set of defensive skin toxins--the steroidal batrachotoxins. The latter are a novel synapomorphy that seems to establish the monophyly of Phyllobates (sensu stricto), a genus heretofore inadequately defined on the basis of shared primitive (simplesiomorphic) characters. Most of the species recently assigned to Phyllobates (by Silverstone, 1976) are here removed to Dendrobates, including the nomenclatural type species (trivittatus) on which the name Dendrobates must be based. Dendrobates is more diverse as now defined (vs. Silverstone, 1975). The diversity is due to a mixture of shared primitive characters, along with derived characters still to be tested for convergence or parallelism. These changes have minimal effect on the usefulness of Silverstone's (1975, 1976) monographs on the two genera, since his accounts of species and species groups are mostly well considered. The laborious process of fabricating an Emberá Chocó blowgun, quiver, and darts is described and photographically illustrated. The Chocó blowgun is of Yde's type IV, two long and tapering, semi-cylindrical sections of palm wood glued together and wrapped with bast. There are two principal ways of making the bore in type-IV blowguns. Some tribes (Jívaro and Yagua) scratch initial grooves on the half-shafts, which are then joined and the bore enlarged and smoothed with a ramrod and sand. The Chocó and Cofán finish the grooves before the half-shafts are joined; use of metal implements by present-day Chocó and Cofán probably is a simple improvement over such objects as mammal teeth, said to have been used for the same purpose by Pasé Indians over a century ago. The Chocó weapon differs from most other type-IV blowguns in lacking a separate mouthpiece and in rarely being water-proofed. The blowgun is for hunting, but, unlike some Amazonian tribes, the Chocó may have no superstitious strictures against turning it occasionally on man. The Chocó are the only Indians known with certainty to use frog toxins as the sole ingredient of dart poison, and the practice is documented only in the Río San Juan and Río Saija drainages of western Colombia; use of a plant poison is more widespread, although the Chocó blowgun iss on the decline and absent in some areas. The Emberá Chocó and Noanamá Chocó have two ways of obtaining frog poison: frogs of the species Phyllobates aurotaenia and P. bicolor (San Juan drainage) are impaled on a special stick entering the mouth and exiting through a hind leg; the spitted frog may sometimes, but not necessarily, be held near fire while darts are rubbed in its skin secretions. In contrast, dart tips are simply rubbed against the backs of living Phyllobates terribilis (Saija region). These different methods reflect more on the relative toxicity and abundance of the frogs than on cultural differences"--P. 311-312.Item Discovery of a defensively malodorous and nocturnal frog in the family Dendrobatidae : phylogenetic significance of a new genus and species from the Venezuelan Andes. American Museum novitates ; no. 3002(New York, N.Y. : American Museum of Natural History, 1991) Myers, Charles W.; Paolillo O., Alfredo.; Daly, John W.Item Discovery of the Costa Rican poison frog Dendrobates granuliferus in sympatry with Dendrobates pumilio, and comments on taxonomic use of skin alkaloids. American Museum novitates ; no. 3144(New York : American Museum of Natural History, 1995) Myers, Charles W.; Daly, John W.; Garraffo, H. Martin.; Wisnieski, Anthony.; Cover, John F."Dendrobates granuliferus, previously thought to be a characteristic endemic of Pacific-side rain forest in the Golfo Dulce region, was found in sympatry with Dendrobates pumilio on the Caribbean coast of southeastern Costa Rica, near the Panamanian border. The sympatric frogs were easily separated by features of coloration and skin texture. Relative abundance in microsympatry was about 100 pumilio:4 granuliferus. Inasmuch as Dendrobates pumilio is sometimes strikingly polymorphic within populations, the initial identifications were tested with bioacoustical, skin-alkaloid, and allozyme data. These comparisons negate the possibility of intrapopulational polymorphism and are consistent with the determination of the rare species as D. granuliferus. Previous inferences that D. granuliferus and D. pumilio are sister species are neither supported nor repudiated by present data. Interpopulational and even individual variation in the skin toxins of these species is extraordinary and probably reflect dietary differences as well as genetic factors. Current knowledge of the dendrobatid alkaloids is briefly reviewed in a systematic context. With a few exceptions, skin chemistry has not been useful in supporting taxonomic differentiation of closely related species. But underlying genetic mechanisms for alkaloid sequestering (and synthesis?) support the monophyly of a suprageneric group of aposematic dendrobatids (tropical poison frogs). Within this group, the monophyly of Phyllobates (true dart-poison frogs) and of Phyllobates + Dendrobates is supported by alkaloid data. The monophyly of Minyobates (dwarf poison frogs) also is corroborated, although in this case the alkaloid character is one of loss and especially in need of further study"--P. [1]-2.Item Madagascan poison frogs (Mantella) and their skin alkaloids / John W. Daly, Nirina Rabe Andriamaharavo, Marta Andriantsiferana, and Charles W. Myers. American Museum novitates ; no. 3177(New York, N.Y. : American Museum of Natural History, 1996) Daly, John W.; Andriamaharavo, Nirina Rabe.; Andriantsiferana, Marta.; Myers, Charles W.Item A name for the poison frog of Cordillera Azul, eastern Peru, with notes on its biology and skin toxins (Dendrobatidae). American Museum novitates ; no. 2674(New York, N.Y. : American Museum of Natural History, 1979) Myers, Charles W.; Daly, John W."Dendrobates silverstonei, new species, is a distinctive orange-and-black or red-and-black frog discovered in the 1940s, as a consequence of road construction across the Cordillera Azul on the Amazonian flank of the Peruvian Andes. A colored photograph of a nurse frog, engaged in the dendrobatid trait of tadpole carrying, was widely promulgated in the multilingual editions of Cochran's Living amphibians of the world, as well as in other popular works. The species is now removed from consideration with Phyllobates bicolor, the only frog with which it has been previously confused or seriously compared. The newly named silverstonei belongs to a group containing the type species of Dendrobates rather than to the demonstrably monophyletic group containing the type species (bicolor) of Phyllobates. The color pattern of D. silverstonei is a convergent autapomorphy showing only the most superficial resemblance to that of P. bicolor, and silverstonei lacks the potent batrachotoxin alkaloids of Phyllobates. Skin secretions contain small amounts of alkaloids, mainly of the pumiliotoxin-A class. Dendrobates siliverstonei is placed tentatively in a species group containing D. trivittatus, because of similarities in morphology and natural history. The highland Dendrobates silverstonei (above 1300 m. elevation) shares various biological attributes with the widespread lowland D. trivittatus (below 800 m.), and their nearly identical songs are described as retarded trill calls, the fourth class of dendrobatid vocalizations to be defined. Both species are wary and usually quick to hide, and both seem to have some preference for edge situations. Similar-sized clutches of eggs of each species have been found in dead leaves on the forest floor, with male frogs in attendance. Tadpoles are carried to terrestrial water by the male nurse frog. There is interpopulational variation in the color pattern of D. silverstonei, and perhaps also in the ontogenetic development of the pattern. Geographic variation is likely to be extensive if the species proves to occupy a large range in the montane forest of Cordillera Azul"--P. [1].Item Preliminary evaluation of skin toxins and vocalizations in taxonomic and evolutionary studies of poison-dart frogs (Dendrobatidae). Bulletin of the AMNH ; v. 157, article 3(New York : American Museum of Natural History, 1976) Myers, Charles W.; Daly, John W."Studies in progress reveal at least three novel classes of toxic alkaloids in skin secretions of Neotropical dendrobatid frogs. Batrachotoxins are characterized by a steroidal ring structure; those batrachotoxins having a pyrrole carboxylate substituent are among the most toxic of nonprotein poisons. Pumiliotoxins are less toxic and poorly known, but pumiliotoxins A and B appear to have a bicyclic ring system with differing side chains; pumiliotoxin C is a simple cis-decahydroquinoline. Histrionicotoxins have an unusual spiro-ring system and both 4-carbon and 5-carbon side chains, on the cyclohexane and piperidine rings, respectively. Structures are uncertain for other alkaloids of lower molecular weight, but some appear structurally related to pumiliotoxins and others to histrionicotoxins. Methods of study include thin-layer chromatography, gas chromatography, electron impact and chemical ionization mass spectrometry, and quantitative mass spectrometry. Combined gas chromatography-mass spectrometry gives reproducible results for small-sample taxonomic comparisons of frogs containing pumiliotoxins, histrionicotoxins, and similar alkaloids. Limitations of molecular data in taxonomic and evolutionary studies are considered. Biochemical and other variation are analyzed in Dendrobates histrionicus, a rain-forest frog of western Colombia and northwestern Ecuador. Sexual dimorphism is slight, and geographic variation in body size appears correlated with climate. There are geographic differences in relative tibia length and in escape behavior. Interpopulational differences in color and color pattern are extreme, and intrapopulational variation also may be considerable. Most colorations are thought to be aposematic, but highly variable frogs of one population seem cryptically colored. Dendrobates histrionicus elaborates histrionicotoxins and lower molecular-weight alkaloids; one population sample had trace amounts of a higher molecular-weight compound, tentatively identified as pumiliotoxin B. Southern populations produce large amounts of histrionicotoxins and lesser amounts of lower weight alkaloids, a situation reversed in most northern populations. Individual populations have 8-10 of 19 alkaloids detected by gas chromatography-mass spectrometry. Alkaloid similarity comparisons show that most populations share more compounds with near than with distant populations; a geographically intermediate population shares as many or more alkaloids with distant as with neighboring populations. Analysis of geographic variation in skin toxins supports the notion of conspecificity of most histrionicus-like frogs, but different spectra of toxins revealed two additional sibling species. These new species resemble D. histrionicus in morphology (including absence of omosternum), vocalizations, and type of male aggressiveness; and their color patterns, although distinctive, are approached in the variation of histrionicus. Dendrobates lehmanni, new species, lacks histrionicotoxins and produces pumiliotoxins and other alkaloids not detected in histrionicus; it is a black frog with crossbands of vivid orange or orange-red. Dendrobates lehmanni was known for years only from specimens sold in the animal trade, but its habitat is traced to a restricted area of montane forest in the Río Anchicayá drainage of the western Andes, Department of Valle, Colombia. Dendrobates occultator, new species, shows greater biochemical resemblance to histrionicus, but shared alkaloid similarity values are relatively low, and it produces significant amounts of pumiliotoxins and only two kinds of histrionicotoxins (5-7 kinds in populations of histrionicus). Dendrobates occultator is a red-backed frog with yellow lateral spots; it occurs in the Pacific lowlands, in the upper Río Saija drainage, Department of Cauca, Colombia, where it is sympatric with a population of histrionicus. Both lehmanni and occultator may have speciated from geographical isolates of histrionicus; it is suggested that some character divergence might have occurred after the range of occultator was rejoined with the parent species. Dendrobates viridis, new species, is also described, as it occurs sympatrically with the other two new species and evidently has an extensive range in Pacific-side Colombia, along the western flank of the Andes. It is a miniature, uniformly green frog, whose skin secretions include pumiliotoxins. Species of Dendrobates in Central America and northwestern South America seem characterized by either of two kinds of vocalizations, which correlate with calling behavior and type of aggressiveness. Buzz calls are a nearly uniform series of pulses, which are produced too fast for resolution by the human ear but which can be directly visualized on sound spectrograms made with a wide-band filter. Buzz calls are given by D. auratus and D. minutus (and 'Phyllobates' espinosai), species that call relatively infrequently and which seem relatively unaggressive. Chirp calls are trains of harsh, poorly modulated notes, in which pulses are produced too fast for resolution on wide-band sound spectrograms. Chirp calls are given by D. granuliferus, D. histrionicus, D. lehmanni, D. occultator, D. pumilio, and D. speciosus -- all of which are characterized by nearly incessant calling from perches, and by pronounced male aggressiveness related to territorial defense. Geographic variation in normal and aggressive calls suggests that D. pumilio may actually be a composite of two species, but biochemical and other variation have yet to be investigated"--P. 177-178.Item Taxonomy and ecology of Dendrobates bombetes, a new Andean poison frog with new skin toxins. American Museum novitates ; no. 2692(New York, N.Y. : American Museum of Natural History, 1980) Myers, Charles W.; Daly, John W."Dendrobates bombetes, new species, is a small, red-striped frog inhabiting the western Andes near Cali, Colombia. Nearest relatives are the Ecuadoran D. abditus and the northern Colombian D. opisthomelas; these three Andean species are considered a monophyletic unit of the 'minutus group' because of a larval synapomorphy. The name D. reticulatus is resurrected from the synonymy of D. quinquevittatus in Amazonian Peru. Dendrobates bombetes was found in two forest types at localities separated by 30 km. distance and 800 m. elevation. Differences in population structure suggest the possibility that either reproductive success or juvenile survivorship may be inversely density dependent. Cool montane forest islands supported dense, presumably stable populations having few juveniles and a high proportion of large (old?) adults. Marginal habitat in relatively xeric gallery forest supported a small population having significantly more juveniles and smaller (younger?) adults, suggesting rapid turnover in a precarious habitat. One or two tadpoles were carried by male nurse frogs, but free-living larvae were not found. The call is a short, surprisingly loud and far-carrying, insect-like buzz influenced by ambient temperature. Rising temperature causes pulse rate to increase and call length to decrease; the second effect probably reinforces the first, since there seems to be an independent tendency for short calls to be pulsed faster than long ones. The call of a related species, Dendrobates opisthomelas, differs even at the same temperature in duration, pulse rate, and dominant frequency. Defensive skin secretions of Dendrobates bombetes contained 22 piperidine alkaloids in the two sampled populations, with 15 or 17 compounds each. Interpopulational variation is partly due to minor differences in degree of saturation of some compounds, and the gas chromatographic profiles are therefore much alike even though the shared-alkaloid value is low (67%). Three new alkaloids form at least a natural subgroup in the pumiliotoxin-A class, to which they are tentatively assigned in spite of anomalous mass spectra; a fourth new alkaloid is placed in the pumiliotoxin-C class"--P. [1].