Amphibia

Anurans and urodeles are known to home to their ponds. The chemical senses as well as vision and other senses are required for this ability. 

The dart-poison frog Dendrobatespumilio uses odors for homing. This species lives in the understory of lowland tropical forests in Central America. The eggs are laid on land, and the female carries the newly hatched tadpoles on her back to water-filled leaf axils of bromeliads. She feeds the tadpoles with unfertilized eggs, while the male defends the territory. Captive dart-poison frogs tested in a Y-olfactometer chose the odor from their own communal tank over odors from tanks planted with different plants. However, they did not distinguish between 

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The major routes of uptake of xenobiotics by animals and plants are discussed in Chapter 4, Section 4.1. With animals, there is an important distinction between terrestrial species, on the one hand, and aquatic invertebrates and fish on the other. The latter readily absorb many xenobiotics directly from ambient water or sediment across permeable respiratory surfaces (e.g., gills). Some amphibia (e.g., frogs) readily absorb such compounds across permeable skin. By contrast, many aquatic vertebrates, such as whales and seabirds, absorb little by this route. In lung-breathing organisms, direct absorption from water across exposed respiratory membranes is not an important route of uptake. 

In birds and amphibia, the green biliverdin IX is excreted in mammals, a soluble enzyme called biliverdin reductase reduces the methenyl bridge between pyrrole III and pyrrole IV to a methylene group to produce bilirubin, a yellow pigment (Figure 32-12). 

Bonin J, Desgranges JL, Bishop CA, Rodrigue J, Gendron A, Elliott E. 1995. Comparative study of contaminants in the mudpuppy (Amphibia) and the common snapping turtle (Reptiha), St. Lawrence River, Canada. Arch Environ Contam Toxicol 28 184-194. 

Geremia, E.C., Corsano, C., Bonomo, R., Giardinelli, R., Vanella, A. and Sichel, G. (1984). Eumelanins as free radical traps and superoxide dismutase activities in amphibia. Comp. Biochcm. Physiol. 79B, 67-69. 

Ritchie (1944) wrote The Organ of Jacobson consists of paired tubular bodies, vascular and richly innervated, lying enclosed in bone in the front of the nasal chamber, and communicating with the nostrils above, and on the other hand with the mouth by two naso-palatine canals which open behind the posterior incisors. It occurs from Amphibia onwards and is probably an accessory organ of smell". 

In the OE of jawed fish only cellular, and little if any, tissue specialisation is achieved. During metamorphosis from tadpole to adult in amphibia, a developmental parallel of water-to-land transition includes the timing of maturation of the AOS. The system as it appears in living amphibians, is already a more or less discrete entity (Fig. 4.3) with its own sub-set of receptors. A process of regionalisation within the bulb, already underway even at the level of organisation in cartilaginous fishes, shows parallel adjustments (Dryer and Graziadei, 1993). 

Fig. 2.3(a) Variations in vertebrate oro-nasal duct systems early Reptile — X Amphibia — 1 Squamates — 2 Lower and Higher Mammals — 3a and b (modified after Bertmar, 1981). 

Fig. 2.3(b) Relations of palate to oral and nasal cavities in A. Amphibia B. Reptiles and C. Mammals, a — p limits of internal nostril, ch = choana, fp = false palate, nc = nasal cavity, npc = naso-palatine canal, and pr = palatine ridge (from Goodrich, 1930 after Seydel, 1899). 

The first air-breathing vertebrates have continued not only to differentiate their chemoreceptor cell types, but also to show some increase in morphological complexity. Amphibia show several adaptive features for fluid intake on land, such as the tentacles of the Caecilians, shown in... 

Fig. 4.3 Morphogenesis during metamorphosis in Amphibia diagramatic sequence of MOS/AOS formation in African Clawed Toad (Xenopus). OP, olfactory placode PC, principal cavity and MC, mid-cavity (from Meyer and Jadhao, 1996).

The chemoreceptive mechanisms in amphibia are undoubtedly worthy of further analysis, not only for their own sake, but to provide clues as to the origination of advanced chemosignal systems. As noted above, a pheromonal signal from the mental gland acts as a courtship/ receptivity inducer. The plethodontid receptivity factor (PRF) (Chap. 3) despite its size (22 kD), seems to have been converted from its internal role as an inter-cellular cytokine, to an inter-individual coordinator of reproductive activity (Rollmann et al., 1999). Endocrine or... 

Amongst amphibia, chemosignalling is most prominent as part of mate location, courtship and mating (Chaps. 2 and 3). Social usage of... 

Andres K. (1970). Anatomy and ultrastructure of the olfactory bulb in fish, amphibia, reptiles, birds and mammals. In Taste and Smell in Vertebrates (Wolstenholme G. and Knight J., eds.). J A Churchill, London, pp. 177-193. 

Herrick C. (1921). Connections of the vomeronasal organ, accessory olfactory bulb and amygdala in amphibia. J Comp Neurol 33, 213-280. 

Himstedt W. and Simon D. (1995). Sensory basis of foraging behaviour in Caecilians (Amphibia, Gymnophiona). Herpetol J 5, 266-270. 

Kolnberger I. (1971). Comparative studies of the olfactory epithelium especially the Vomeronasal (Jacobson s) Organ in Amphibia, Reptiles and Mammals. Z Zellf Mikrosk Anat 122, 53-67. 

Blem, C.R. and L.B. Blem. 1991. Cation concentrations and acidity in breeding ponds of the spotted salamander, Ambystoma maculatum (Shaw) (Amphibia Ambystomatidae), in Virginia. North Carol. State Mus. Natur. Hist. 17 67-76. 

Yeung, G.L. 1978. The influence of lead, an environmental pollutant on metamorphosis of Rana utricularia (Amphibia Ranidae). Arkansas Acad. Sci. Proc. 32 83-86. 

Houck, L.D. and Arnold, SJ. (2003) Courtship and mating. In D.M. Sever (Ed.), Phytogeny and Reproductive Biology of Urodela (Amphibia). Science Publishers Inc., Enfield, New Hampshire, 383 124. 

Larson, A. and Highton, R. (1978) Geographic protein variation and divergence of the salamanders in the Plethodon welleri group (Amphibia Plethodontidae). Syst. Zool. 27, 431 —448. 

Andren, C. (1986) Courtship, mating and agonistic behavior in the free-living population of adders, Vipera berus (L.). Amphibia-Reptilia 7, 353-383. 

Punzo, F. and Parker, L. G. (2006) Food-deprivation affects tongue extrusions as well as attractivity and proceptivity components of sexual behavior in the lizard, Sceloporus jarrovii. Amphibia-Reptilia 27, 377-383. 

Brizzi, R., Delfino, G. and Pellegrini, R. (2002) Specialized mucous glands and their possible adaptive role in the males of some species of Rana (Amphibia, Anura). J. Morph. 254, 328-341. Chen, C. and Osuch, M. V. (1969) Biosynthesis of bufadienolides - 3Bhydroxycholonates as precursors in Bufo marinus bufadienolides synthesis. Biochem. Pharmacol. 18, 1797-1802. Chivers, D. P. and Smith, R. J. F. (1998) Chemical alarm signalling in aquatic predator-prey systems a review and prospectus. Ecosci. 5, 338-352. 

In amphibia that do not need a Root effect, the alkaline Bohr effect is weakened by a variety of single substitutions Ser F9 — Ala in the tadpoles of Xenopus and R. catesbeiana Glu FGl/8 — Asn or Gly in adult frogs and in one of the tadpoles His HC3 — Phe in another tadpole. It looks as though once a function is no longer needed any mutation that inhibits the function becomes fixed (97). 

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