A nuptial pad (also known as thumb pad, or nuptial excrescence [1] ) is a secondary sex characteristic present on some mature male frogs and salamanders. [2] [3] [4] [5] Triggered by androgen hormones, this breeding gland (a type of mucous gland) appears as a spiked epithelial swelling on the forearm and prepollex that aids with grip, which is used primarily by males to grasp (or clasp) females during amplexus. [6] They can also be used in male–male combat in some species. [6]
Austrian biologist Paul Kammerer experimented on midwife toads' nuptial pads. [7] He used the offspring's apparent enlargening from generation-to-generation as evidence of Lamarckian evolution. [8]
Many amphibian species manifest nuptial pads for use in amplexus, an example being the rough-skinned newt, Taricha granulosa. [9]
Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arboreal or freshwater aquatic ecosystems. Thus amphibians typically start out as larvae living in water, but some species have developed behavioural adaptations to bypass this.
Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten extant salamander families are grouped together under the order Urodela from the group Caudata. Salamander diversity is highest in eastern North America, especially in the Appalachian Mountains; most species are found in the Holarctic realm, with some species present in the Neotropical realm.
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura. The oldest fossil "proto-frog" Triadobatrachus is known from the Early Triassic of Madagascar, but molecular clock dating suggests their split from other amphibians may extend further back to the Permian, 265 million years ago. Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforest. Frogs account for around 88% of extant amphibian species. They are also one of the five most diverse vertebrate orders. Warty frog species tend to be called toads, but the distinction between frogs and toads is informal, not from taxonomy or evolutionary history.
Amplexus is a type of mating behavior exhibited by some externally fertilizing species in which a male grasps a female with his front legs as part of the mating process, and at the same time or with some time delay, he fertilizes the eggs, as they are released from the female's body. In amphibians, females may be grasped by the head, waist, or armpits, and the type of amplexus is characteristic of some taxonomic groups.
Salamandridae is a family of salamanders consisting of true salamanders and newts. Salamandrids are distinguished from other salamanders by the lack of rib or costal grooves along the sides of their bodies and by their rough skin. Their skin is very granular because of the number of poison glands. They also lack nasolabial grooves. Most species of Salamandridae have moveable eyelids but lack lacrimal glands.
The genus Taricha consists of four species of highly toxic newts in the family Salamandridae. Their common name is Pacific newts, sometimes also western newts or roughskin newts. The four species within this genus are the California newt, the rough-skinned newt, the red-bellied newt, and the sierra newt, all of which are found on the Pacific coastal region from southern Alaska to southern California, with one species possibly ranging into northern Baja California, Mexico.
The rough-skinned newt or roughskin newt is a North American newt known for the strong toxin exuded from its skin.
The California newt or orange-bellied newt, is a species of newt endemic to California, in the Western United States. Its adult length can range from 5 to 8 in. Its skin produces the potent toxin tetrodotoxin.
The western toad is a large toad species, between 5.6 and 13 cm long, native to western North America. A. boreas is frequently encountered during the wet season on roads, or near water at other times. It can jump a considerable distance for a toad. Breeding occurs between March and July in mountainous areas, and as early as January in lower-elevation regions. The female lays up to 17,000 eggs stuck together in strings that adhere to vegetation and other objects along water edges.
The red-spotted toad, formerly Bufo punctatus, is a toad in the family Bufonidae found in the southwestern United States and northwestern Mexico.
The Pacific tree frog, also known as the Pacific chorus frog, has a range spanning the Pacific Northwest, from Northern California, Oregon, and Washington to British Columbia in Canada and extreme southern Alaska. They live from sea level to more than 10,000 feet in many types of habitats, reproducing in aquatic settings. They occur in shades of greens or browns and can change colors over periods of hours and weeks.
The foothill yellow-legged frog is a small-sized frog from the genus Rana in the family Ranidae. This species was historically found in the Coast Ranges from northern Oregon, through California, and into Baja California, Mexico as well as in the foothills of the Sierra Nevada and southern Cascade Range in California. The foothill yellow-legged frog is a Federal Species of Concern and California State Endangered. A federal rule to list four out of six extant distinct population segments (DPS) under the Endangered Species Act was proposed in December 2021.
The Sierra newt is a newt found west of the Sierra Nevada, from Shasta county to Tulare County, in California, Western North America.
The Betic midwife toad or Sapo Partero Bético is a species of frog in the family Alytidae. It is endemic to mountainous in south eastern Spain. Its natural habitats are temperate forests, freshwater marshes, intermittent freshwater marshes, pastureland, ponds, and aquaculture ponds. It is threatened by habitat loss.
A newt is a salamander in the subfamily Pleurodelinae. The terrestrial juvenile phase is called an eft. Unlike other members of the family Salamandridae, newts are semiaquatic, alternating between aquatic and terrestrial habitats. Not all aquatic salamanders are considered newts, however. More than 100 known species of newts are found in North America, Europe, North Africa and Asia. Newts metamorphose through three distinct developmental life stages: aquatic larva, terrestrial juvenile (eft), and adult. Adult newts have lizard-like bodies and return to the water every year to breed, otherwise living in humid, cover-rich land habitats.
The Crater Lake newt or Mazama newt, Taricha granulosa mazamae, is a subspecies of the rough-skinned newt. Its type locality is Crater Lake, Oregon. Similar newts have been found in Alaska, but their identity is unclear.
The Coastal Range newt is a subspecies of the California newt. It is endemic to California, from Mendocino County south to San Diego County.
There are 14 species of amphibians and 5 species of reptiles known to occur in Mount Rainier National Park.