The evidentiary basis of the currently accepted classification of living amphibians is discussed and shown not to warrant the degree of authority conferred on it by use and tradition. A new taxonomy of living amphibians is proposed to correct the deficiencies of the old one. This new taxonomy is based on the largest phylogenetic analysis of living Amphibia so far accomplished. We combined the comparative anatomical character evidence of Haas (2003) with DNA sequences from the mitochondrial transcription unit H1 (12S and 16S ribosomal RNA and tRNAValine genes, ≈ 2,400 bp of mitochondrial sequences) and the nuclear genes histone H3, rhodopsin, tyrosinase, and seven in absentia, and the large ribosomal subunit 28S (≈ 2,300 bp of nuclear sequences; ca. 1.8 million base pairs; x = 3.7 kb/terminal). The dataset includes 532 terminals sampled from 522 species representative of the global diversity of amphibians as well as seven of the closest living relatives of amphibians for outgroup comparisons. The...

https://bioone.org/journals/Bulletin-of-the-American-Museum-of-Natural-History/volume-2006/issue-297/0003-0090(2006)297[0001:TATOL]2.0.CO;2/THE-AMPHIBIAN-TREE-OF-LIFE/10.1206/0003-0090(2006)297[0001:TATOL]2.0.CO;2.pdf

The amphibian tree of life

The toad, ugly and venomous, wears yet a precious jewel in his skin

Poison frogs (Family Dendrobatidae) are common leaf litter inhabitants of New World tropical rainforests. The name of this group derives from several genera (especially Dendrobates, Minyobates, and Phyllobates) that are aposematically coloured and have toxic skin to varying degrees. Other species in the family, primarily the genus Colostethus, are cryptically coloured and non-toxic. Recent studies have revealed that the toxic compounds in the skin, which are lipophilic alkaloids, may have a dietary origin. Diets and associated characteristics, prey size, prey number, and niche breadth, of nine species in five genera, three of which have poisonous species, were examined. Interpretation of these characteristics in light of an independently constructed cladogram revealed the inclusion of a high percentage of Formicidae (ants) in the diets of toxic species. Although alkaloids have been reported in several insect groups, more alkaloids are known from ants than any other group. Species in the genus Dendrobates, which are poisonous and have many other derived characters, have diets composed of 50–73% ants, whereas percentages of ants used by non-toxic species in the genus Colostethus was 12–16%. Ants are the major prey category consumed by the five poisonous species considered in this study. In general, frogs separated into two groups. More basal groups with non-toxic skin and cryptic coloration had diets with low percentages of ants, low numbers of prey per individual, and high niche breadths, indicating inclusion of a broad range of prey categories in their diets. Species with poisonous skin and aposematic coloration had diets with large percentages of ants, large numbers of prey per individual, and low niche breadths, indicating diets with relatively few prey categories. Thus, diet, and the subsequent evolution of uptake systems for alkaloids, may be the primary character that led to the development of toxic skin and permitted aposematism, leading to radiation of poisonous species.

The evolution of myrmecophagy and its correlates in poison frogs (Family Dendrobatidae)

. A phylogeny of the species-rich clade of the Neotropical frog genus Leptodactylus sensu stricto is presented on the basis of a total evidence analysis of molecular (mitochondrial and nuclear markers) and non-molecular (adult and larval morphological and behavioral characters) sampled from > 80% of the 75 currently recognized species. Our results support the monophyly of Leptodactylus sensu stricto, with Hydrolaetare placed as its sister group. The reciprocal monophyly of Hydrolaetare and Leptodactylus sensu stricto does not require that we consider Hydrolaetare as either a subgenus or synonym of Leptodactylus sensu lato. We recognize Leptodactylus sensu stricto, Hydrolaetare, Adenomera, and Lithodytes as valid monophyletic genera. Our results generally support the traditionally recognized Leptodactylus species groups, with exceptions involving only a few species that are easily accommodated without proposing new groups or significantly altering contents. The four groups form a pectinate tree, wi...

https://bioone.org/journals/south-american-journal-of-herpetology/volume-9/issue-s1/SAJH-D-13-00022.1/Systematics-of-the-Neotropical-Genus-Leptodactylus-Fitzinger-1826-Anura/10.2994/SAJH-D-13-00022.1.pdf

Systematics of the Neotropical Genus Leptodactylus Fitzinger, 1826 (Anura: Leptodactylidae): Phylogeny, the Relevance of Non-molecular Evidence, and Species Accounts

Defensive mechanisms, including noxious or toxic substances, are favored by predation‐driven natural selection. The acquisition of noxious/toxic substances can be either endogenous, in which the substances are produced by the organism, or exogenous, in which the substances are produced by another organism and are sequestered. Evidence indicates that the defensive skin alkaloids of Neotropical poison frogs (Dendrobatidae) have an exogenous source: a diet of ants and other small alkaloid‐containing arthropods, which we term the diet‐toxicity hypothesis. A critical prediction of the diet‐toxicity hypothesis is that independent origins of dietary specialization will be found to be correlated with independent origins of skin alkaloids. We tested this prediction in an integrated framework using comparative methods with new and published data on feeding ecology and chemical defense for 15 species of dendrobatids in five genera. We found a significant correlation between alkaloid profiles and degree of ...

https://www.jstor.org/stable/10.1086/426599

Evolution of dietary specialization and chemical defense in poison frogs (Dendrobatidae): a comparative analysis.

............................................ 2 Resumen ............................................. 2 Introduction ............................................. 2 Aromobates, new genus ................. ............................ 4 Aromobates nocturnus, new species .......................................... 4 Description ............................................. 5 Myology ............................................. 8 Osteology ............................................. 9 Tadpoles ............................................. 12 Biochemistry of Skin Secretions ............................................ 14 Distribution and Natural History ............................................ 14 Familial Placement and Comparisons ............................................ 16 Toward a Definition of Colostethus Cope (1866) ................ ................ 18 On the Name Hyloxalus Jimenez de la Espada (1871) ........... ................ 19 Comparisons with "Collared Colostethus"........................................ 19 Phylogenetic Position ................ ............................ 28 References.............29 References~~~~~ ...... .. .. .. ......... .. .. .. ......... 2 Appendix: Notes on Colostethus riveroi .......................................... 32 ' Curator, Department of Herpetology and Ichthyology, American Museum of Natural History. 2 Field Associate in Herpetology, American Museum ofNatural History; Director ofScientific Information, BIOMA, Fundaci6n Venezolana para la Conservaci6n de la Diversidad Biol6gica, Caracas. 3 Research Associate in Herpetology, American Museum of Natural History; Chief, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health. Copyright © American Museum of Natural History 1991 ISSN 0003-0082 / Price $3.50 AMERICAN MUSEUM NOVITATES

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

Alfredo. Paolillo O.

Papers

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