Morphology of the parotoid macroglands in <i>Phyllomedusa</i> leaf frogs

Antoniazzi, Marta Maria; Neves, Patrícia; Mailho‐Fontana, Pedro Luiz; Rodrigues, Miguel Tréfaut; Jared, Carlos

doi:10.1111/jzo.12044

Cited by 33 publications

(38 citation statements)

References 26 publications

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“…As the basal bufonid Rhaebo guttatus also presents a complex parotoid macrogland composed of highly packed glands (Jared et al, ; Mailho‐Fontana et al, ), parotoids in bufonids seem to be a specialized macrogland different from parotoids of other groups. For instance, parotoids of hylids do not share the same complex arrangement as those of bufonids, and their secretion products are of a different chemical nature (Antoniazzi et al, ). Another example of a macrogland consisting of a complex arrangement of glands is the femoral gland of some mantelline frogs, which consists of circularly arranged granular glands that secrete their products into a central external depression (Vences et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…Our study of the ontogeny of the postorbital/supratympanic region showed that these diverse types of glands differentiate from similar syncytial glands, suggesting that the differentiation of the glands occurs during postmetamorphic development. A particular characteristic of the parotoid gland of bufonids is the presence of differentiated mucous glands around the duct of the large glands (Jared et al, ; Antoniazzi et al, ); in R. arenarum , these mucous glands were only observed around the duct of the central glands. Glands surrounding the ducts differ from the other mucous glands of the body, both in their function and their morphological characteristics.…”

Section: Discussionmentioning

confidence: 99%

“…The skin of extant adult amphibians consists of an epidermis and an underlying dermis with two types of glands, considered synapomorphies of Lissamphibia: mucous glands, usually associated with respiration and water balance, and granular (also known as serous or venom) glands, related to defense mechanisms (Duellman and Trueb, ). Granular glands synthesize a wide variety of chemical compounds, e.g., proteins, lipids, catecholamines, alkaloids, or glycoconjugates, depending on the group of amphibians (Toledo and Jared, ; Jared et al, ; Antoniazzi et al, ; Ferraro, Topa and Hermida, ). Among anurans, true toads belonging to the family Bufonidae produce highly toxic skin secretions, which are composed of cardiotonic steroids, called bufadienolides, and biogenic amines like catecholamines, with a powerful vasopressor action in vertebrates (Toledo and Jared, ; Maciel et al, ; Cunha‐Filho et al, ; Sciani et al, ).…”

Section: Introductionmentioning

confidence: 99%

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Morphological Changes in Skin Glands During Development in Rhinella Arenarum (Anura: Bufonidae)

Regueira

Dávila

Hermida

2015

The Anatomical Record

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Avoiding predation is critical to survival of animals; chemical defenses represent a common strategy among amphibians. In this study, we examined histologically the morphology of skin glands and types of secretions related to chemical skin defense during ontogeny of Rhinella arenarum. Prior to metamorphic climax the epidermis contains typical bufonid giant cells producing a mucous substance supposedly involved in triggering a flight reaction of the tadpole school. An apical layer of alcianophilic mucus covers the epidermis, which could produce the unpleasant taste of bufonid tadpoles. Giant cells disappear by onset of metamorphic climax, when multicellular glands start developing, but the apical mucous layer remains. By the end of climax, neither the granular glands of the dorsum nor the parotoid regions are completely developed. Conversely, by the end of metamorphosis the mucous glands are partially developed and secrete mucus. Adults have at least three types of granular glands, which we designate type A (acidophilic), type B (basophilic) and ventral (mucous). Polymorphic granular glands distribute differently in the body: dorsal granular glands between warts and in the periphery of parotoids contain protein; granular glands of big warts and in the central region of parotoids contain catecholamines, lipids, and glycoconjugates, whereas ventral granular glands produce acidic glycoconjugates. Mucous glands produce both mucus and proteins. Results suggest that in early juveniles the chemical skin defense mechanisms are not functional. Topographical differences in adult skin secretions suggest that granular glands from the big warts in the skin produce similar toxins to the parotoid glands. Anat Rec, 299:141-156, 2016. V C 2015 Wiley Periodicals, Inc.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Morphological Changes in Skin Glands During Development in Rhinella Arenarum (Anura: Bufonidae)

Regueira

Dávila

Hermida

2015

The Anatomical Record

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“…Occurrence of three serous gland types is unusual in anuran skin, where no more than two different types were previously reported. Actually, three syncytial gland types have been also described in leaf frogs of the genus Phyllomedusa (Delfino et al, ; Nosi et al, ), but this variety includes secretory units specialized in producing skin wax (Blaylock et al, ; Antoniazzi et al, ) that therefore represent a serous‐derived rather than a proper serous type (Delfino et al, ).…”

Section: Discussionmentioning

confidence: 99%

Ultrastructural Evidence of Serous Gland Polymorphism in the Skin of the Tungara Frog Engystomops pustulosus (Anura Leptodactylidae)

Delfino

Giachi

Malentacchi

et al. 2015

The Anatomical Record

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Three types of serous products were detected in the syncytial cutaneous glands of the leptodactylid tungara frog, Engystomops pustulosus: type Ia, granules with wide halos and variable density cores; type Ib, high density granules without halos; and type II, vesicles containing a finely dispersed product. Ultrastructural evidence revealed that these products were manufactured by different serous gland types and excluded that they represented different steps in the secretory cycle of a single gland type. Indeed, secretory maturation affecting the products released by the Golgi apparatus proceeded through different mechanisms: confluence (vesicles), interactions between syncytium and secretory product (type Ib granules), and a combination of both processes (type Ia granules). In conclusion, this investigation of secretory maturation was shown to be a suitable approach for the identification of serous gland polymorphism and demonstrated that the tungara frog belongs to the minority of anuran species characterized by this peculiar morpho-functional trait.

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“…Therefore, it is the predator who causes its own poisoning, which can often be lethal (Sakate and Lucas de Oliveira, ; Jared and Antoniazzi, ; Jared et al, ). Predator's self‐poisoning is characteristic of amphibian defense, which is classified as a “passive defense” (Jared and Antoniazzi, ; Antoniazzi et al, ), as opposed to “active defense” presented, for example, by the snakes, who attack the aggressor and inject their venom through glands compressed by surrounding muscles (Kochva, ; Pough et al, ; Jared et al, ).…”

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confidence: 99%

Passive and active defense in toads: The parotoid macroglands inRhinella marinaandRhaebo guttatus

et al. 2013

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Amphibians have many skin poison glands used in passive defense, in which the aggressor causes its own poisoning when biting prey. In some amphibians the skin glands accumulate in certain regions forming macroglands, such as the parotoids of toads. We have discovered that the toad Rhaebo guttatus is able to squirt jets of poison towards the aggressor, contradicting the typical amphibian defense. We studied the R. guttatus chemical defense, comparing it with Rhinella marina, a sympatric species showing typical toad passive defense. We found that only in R. guttatus the parotoid is adhered to the scapula and do not have a calcified dermal layer. In addition, in this species, the plugs obstructing the glandular ducts are more fragile when compared to R. marina. As a consequence, the manual pressure necessary to extract the poison from the parotoid is twice as high in R. marina when compared to that used in R. guttatus. Compared to R. marina, the poison of R. guttatus is less lethal, induces edema and provokes nociception four times more intense. We concluded that the ability of R. guttatus to voluntary squirt poison is directly related to its stereotyped defensive behavior, together with the peculiar morphological characteristics of its parotoids. Since R. guttatus poison is practically not lethal, it is possibly directed to predators' learning, causing disturbing effects such as pain and edema. The unique mechanism of defense of R. guttatus may mistakenly justify the popular myth that toads, in general, squirt poison into people's eyes.

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Morphology of the parotoid macroglands in Phyllomedusa leaf frogs

Cited by 33 publications

References 26 publications

Morphological Changes in Skin Glands During Development in Rhinella Arenarum (Anura: Bufonidae)

Morphological Changes in Skin Glands During Development in Rhinella Arenarum (Anura: Bufonidae)

Ultrastructural Evidence of Serous Gland Polymorphism in the Skin of the Tungara Frog Engystomops pustulosus (Anura Leptodactylidae)

Passive and active defense in toads: The parotoid macroglands inRhinella marinaandRhaebo guttatus

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