Bolitoglossa

Diversity

In the genus Bolitoglossa there are seven sub-genera: Bolitoglossa, Eladinea, Magnadigita, Mayamandra, Nanotriton, Oaxakia, and Pachymandra (Townsend et al., 2009). These are commonly known as mushroom tongue salamanders. 131 species have been described through 2017. All are located in Central and South America from Mexico to Columbia, Ecuador to Costa Rica (Rovito et al., 2012). All identified species live from elevations of 90 to 3000 m (Acosta-Galvis and Gutierrez-Lamu, 2012). These habitats include paramo, Andean forest, subAndean forest and tropical lowlands. This genus of salamanders is highly varied in terms of behavior and morphological characteristics. They can be diurnal or nocturnal as well as be found in arboreal habitats; in bromeliads or terrestrial habitats under rotten logs or on moss patches.(Leonardo Meza-Joya, Andres Hernandez-Jaimes, and Ramos-Pallares, 2017)

The morphology of these tropical salamanders is only consistent within sub-genera or species in relation to relative size, head shape, eye protuberance, labial protuberances, relative number of costal grooves, and degree of foot webbing (Rovito et. al., 2012). Otherwise, there is a high degree of variation in coloration, snout/vent length, foot morphology, and other characteristics even between juveniles and adults as well as males and females of a singular species (Townsend et. al., 2009). (Acosta-Galvis and Gutiérrez-Lamu, 2012; Leonardo Meza-Joya, et al., 2017; Rovito, et al., 2012; Townsend, et al., 2009)

Geographic Range

Salamanders in the genus Bolitoglossa are native to Central and South America and are considered tropical or neotropical. The highest northern latitude they reach is approximately 24 degrees north at Tamaulipas, Mexico. Ranges extend south into Bolivia (Cruz et. al., 2008). Some species are endemic to Cordilleras regions in Colombia and Venezuela and the Montana de Celaque, the Sierra de Opalaca and the Sierra de Montecillos in southwestern Honduras (Acosta-Galvis and Gutierrez-Lamu, 2012). Many of the widespread species may be cryptic complexes. (Acosta-Galvis and Gutiérrez-Lamu, 2012; Cruz, et al., 2008; Rovito, et al., 2012; Schargel, et al., 2002)

Habitat

The habitats of the species in Bolitoglossa are highly varied and range from arboreal to terrestrial (IUCN SSC Amphibian Specialist Group, 2014). Some are found in bromeliads high in the tree canopy as well as on the ground under leaf litter or on short shrubs (ferns) and vegetation (B. celaque, B. dunni, B. cataguana, B. tica) (Townsend et al., 2009). B. chinanteca is arboreal and is specifically found on the axils of banana plants (Garcia-Paris, Parra-Olea, and Wake, 2008.

Habitat is dependent on the behavior of the salamanders (diurnal/nocturnal). They will sometimes stay in the upper canopy during the day while sleeping and then travel down to the forest floor to feed or mate and rest on ferns, under logs or on road banks (Rovito et al., 2012). (Cruz, et al., 2008; Garcia-Paris, et al., 2008; "Amphibiaweb", 2014; Rovito, et al., 2012; Townsend, et al., 2009)

Physical Description

These salamanders are usually between 35-45mm in SVL (snout vent length) (Bolanos, Robinson, and Wake, 1987). From this you can tell they are very small even when adults. For many of the species within this genus, the majority of their length is found in their tail region. They stand anywhere from 5-10mm off the ground (Carvalho Brcko, Steven Hoogmoed, and Neckel-Oliveira, 2015).The heads of these animals are broad with blunt snouts, they have protruding eyes and well defined nasolabial grooves and protuberances. Many of the salamander species have distinct costal grooves and smooth skin. The feet are likely the largest source of variation among species and species complexes; the feet can have no to little inter-digital webbing or a high degree (Garcia-Paris, Parra-Olea, and Wake, 2008).

The coloration varies, however the dorsum is typically brown or tan (B. guaneae and B. gracilis) and can have mottled splotches, stripes or spots (Rovito et al., 2012). The ventrum is almost always lighter than the dorsum and the irises can be golden, copper or just brown in color. Many members of Bolitoglossa have juveniles with different coloration as in the case of B. gracilis and its yellow and black juveniles (Townsend et al., 2009).

There is some sexual dimorphism mostly in the increased size of females as compared to males.The males also have bigger teeth at the front of their mouths that pierce the lower jaw (Carvalho Brcko, Steven Hoogmoed, and Neckel-Oliveira, 2015). (Acosta-Galvis and Gutiérrez-Lamu, 2012; Bolanos, et al., 1987; Carvalho Brcko, et al., 2015; Garcia-Paris, et al., 2008; Rovito, et al., 2012; Townsend, et al., 2009)

  • Sexual Dimorphism
  • female larger
  • sexes shaped differently
  • ornamentation

Development

Embryonic development is atypical of most Caudates (salamanders/newts). Species in Bolitoglossa and all others within Plethodontidae are direct developers and the young develop outside the reproductive tract (Wake and Hanken, 1996). The female will deposit the fertilized eggs onto the ground (unlike anuran eggs, these often have a thick, leathery, covering) and when it comes time to hatch, the young salamanders emerge as tiny versions of the adults. There is no metamorphosis stage. (Wake and Hanken, 1996)

Reproduction

Males and females of Bolitoglossa live solitary lives until it comes time to mate (Vial, 1968). Little is known about their mating behavior overall. In other Plethodontid salamanders, the males will place a sperm sac on the ground and competing males will lay their sperm packet on top of the others. Females likely walk over these packets and pick them up with their cloaca. Some North American salamanders closely related to Bolitoglossa have a "dance" where males lead females over their sperm packet and this is why males help with watching over the development of the clutch (Vial, 1968). This is a possibility with the neotropical salamanders in this genus since there is typically parental care. (Vial, 1968)

Males mature between 4 and 9-years-old while females mature later (between 9 and 14-years-old) (Vial, 1968). Males show maturity when they express teste lobes and protruding teeth. Females will have thickened oviducts and enlarged ova most of the year, but it is still unknown what cues the females follow in order to become gravid (Vial, 1968).

Eggs are laid in under rocks or decaying logs and must be large enough to fit the eggs and the attending parent who will spend most of the gestation tightly wrapped around their clutch (Vial, 1968). (Vial, 1968)

  • Parental Investment
  • pre-fertilization
    • protecting
  • pre-hatching/birth
    • protecting

Lifespan/Longevity

Nothing has been documented about the longevity of the members in Bolitoglossa. An estimate from a paper says salamanders as a whole can live up to thirty-five years (Staub, 2016). (Staub, 2016)

Behavior

Bolitoglossine salamanders can be both arboreal and terrestrial due to their foot morphology and nocturnal pattern of behavior to hide under rotten logs on the forest floor during the day and climb trees/herbaceous plants at night. As far as we know, they are solitary and only congregate to mate. They have very small home ranges which regularly overlap basically over a few trees or the area of one square meter.

Other behaviors are not well documented for Bolitoglossa, however, there is a lot of data for the closely related genus Plethodon. Research has shown that they display intrasexual agonistic/territorial behaviors including all trunk raised and biting. They can also show submission by flattening their trunk to the substrate (Jaeger, 1984).

As well, mating behavior is also unknown for these salamanders, but assuming they are similar to other Plethodontid salamanders they perform the same mating rituals. Males will "vaccinate" females with pheromones by scratching her skin with premaxillary teeth and then rubbing a gland over the wound (Houck and arnold, 2003). The male then leads the receptive female behind him, he releases a spermatophore onto the ground, the female walks forward and picks up the sperm packet with her cloaca (Ducey et al., 1993). Again, this might not be the case with Bolitoglossa, but it is a list of potentially applicable information. (Ducey, et al., 1993; Houck and Arnold, 2003; Jaeger, 1984)

Communication and Perception

Members of Bolitoglossa all possess nasolabial protuberances that assist with picking up chemical signals. The way that the signals are sent is through glands usually on the head of the salamander which are then rubbed against substrate or on other salamanders. Sometimes the pheromones are picked up via an olfactory pathway or transdermally as seen during mating behaviors (Jaeger and Forester, 1993).

No research has been done on the pheromone communication of bolitoglossine salamanders, but here we predict possible traits based on what is known in related species.

This type of communication is performed between males and females for courtship or between males for territorial displays. Courtship pheromones make the females receptive to sperm transfer by making the process shorter. Territorial pheromones can communicate dear enemy or dear neighbor relationships and size of competitors (Woodley 2010).

Other forms of communication involve visual cues from posturing that can represent submission, aggression, fright, sexual receptivity. This is usually done by raising or lowering the trunk, undulating the tail, or movement towards or away from a stimulus. There is some research on the detection of substrate vibrations by salamanders as well (jaeger, 1984). (Jaeger, 1984; Jaeger and Forester, 1993; Staub, 2016; Woodley, 2010)

Food Habits

The most common food source of Bolitoglossa are hymenopterans in the family Formicidae (ants). The next most common are non-formicid hymenopterans, coleopterans (beetles), and orthopterans (grasshoppers) (Anderson and Mathis, 1999). Bolitoglossa mexicana and B. rufescens have also been documented to eat minute amounts of nonaranid arachnids, collembolans, and isopterans (Anderson and Mathis, 1999)

An adaptation for insectivory in Bolitoglossa is the use of the hyoid apparatus to support the tongue as well as launch it towards prey items. Many members of this genus have projectile tongues or have similar capabilities. (Anderson and Mathis, 1999)

Predation

The first line of defense for these salamanders is to remain still and blend in with their surroundings. Most of the salamanders in this genus have cryptic coloration that is typically brown and mottled to match dirt or wooden branches (Ducey et al., 1993).

Another strategy is tail autonomy which is the ability for the salamander to lose a portion of its tail so that it can get away while the predator is preoccupied with the the withering tail. Luckily these salamanders are excellent at regenerating appendages so the tail will heal and grow back to a small degree.

In a study done on anti-predator skin secretions, Bolitoglossa rostrata and B. subpalmata are known to secrete toxins from their skin that when ingested by species in the genus Thamnophis (garter snakes) become incapacitated and often die (Brodie Jr. and Ducey, 1991).

Another study showed that these salamanders perform anti-predator behaviors immediately before or after a strike including arching the back and undulating the tail or wrapping their body around the head of the snake (Brodie Jr. and Ducey, 1991). (Brodie Jr. and Ducey, 1991; Ducey, et al., 1993)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Little is known about the ecological roles of Bolitoglossa however they act as prey to a number of reptile species and are predators to many insects, molluscs and crustraceans (Anderson and Mathis, 1999; Brodie Jr. and Ducey, 1991)

Economic Importance for Humans: Positive

These tropical salamanders along with thousands of other organisms that inhabit Central and South America are all crucial for the ecotourism industry. Countries like Honduras, Costa Rica, Ecuador, Belize, and Bolivia all rely on ecotourism in their economies because a lot of their land is protected and can't be used for agriculture, resource exploitation or other businesses. Therefore, the people take advantage of the beautiful and diverse wildlife areas that attract tourists to make money from serving as tour guides, offering handmade souvenirs, running hotels and restaurants etc.

Very little research has been done on these salamanders especially in the realms of behavior and cryptic diversity so it is intriguing to scientists to study Bolitoglossa for the wealth of information that awaits to be discovered.

  • Positive Impacts
  • ecotourism
  • research and education

Economic Importance for Humans: Negative

There are no known adverse effects of Bolitoglossa on humans.

Conservation Status

The main threat to Bolitoglossa is habitat loss or fragmentation due to agriculture and development of infrastructure (Cruz et al., 2008). Species such as B. dunni and B. celaque are considered endangered according to the IUCN Redlist of Threatened Species so we can assume that many other members of the genus are also threatened or endangered (IUCN SSC Amphibian Specialist Group, 2014). Currently, the geographic ranges of these salamanders fall on protected natural areas including Parque Nacional Cusuco and Parque Nacional Cerro Azul in Honduras and Parque Nacional Cerro Celaque, Reserva Biológica de Guajiquiro, Reserva Biológica de Opalaca and Reserva Biológica de Montecillos; many of which are located in Honduras (Cruz et al., 2008). Residing in these protect National parks means that they can't be killed or collected and their habitat can't be either. This is good news for these salamanders and even better for the ecotourism opportunities in the countries they live in. This money is sometimes spent for the conservation of endangered species in order to buy land to protect from development. (Cruz, et al., 2008; "Amphibiaweb", 2014)

  • IUCN Red List [Link]
    Not Evaluated

Other Comments

Current research on these and other closely related salamanders pertains to their disproportionally large genome size which is shown to impact cell size and development (Sessions and Larson, 1987). (Sessions and Larson, 1987)

Contributors

Claire Crookston (author), Colorado State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

agricultural

living in landscapes dominated by human agriculture.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

cooperative breeder

helpers provide assistance in raising young that are not their own

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

insectivore

An animal that eats mainly insects or spiders.

internal fertilization

fertilization takes place within the female's body

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

molluscivore

eats mollusks, members of Phylum Mollusca

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

scrub forest

scrub forests develop in areas that experience dry seasons.

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

solitary

lives alone

tactile

uses touch to communicate

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

vibrations

movements of a hard surface that are produced by animals as signals to others

year-round breeding

breeding takes place throughout the year

References

IUCN SSC Amphibian Specialist Group. 2014. "Amphibiaweb" (On-line). Bolitoglossa dunni. Accessed January 29, 2018 at https://amphibiaweb.org/cgi/amphib_query?where-genus=Bolitoglossa&where-species=dunni.

Acosta-Galvis, A., D. Gutiérrez-Lamu. 2012. A new species of salamander (Bolitoglossa: Plethodontidae) from the Cordillera Oriental of the Colombian Andes. Papeis Avulsos de Zoologia: Museu de Zoologia da Universidade de Sao Paulo, 52/18: 201-218. Accessed January 29, 2018 at http://www.scielo.br/pdf/paz/v52n18/a01v52n18.pdf.

Anderson, M., A. Mathis. 1999.

Diets of Two Sympatric Neotropical Salamanders, Bolitoglossa mexicana and B. rufescens, with Notes on Reproduction for B. rufescens
. Journal of Herpetology, 33/04: 601-607. Accessed March 04, 2018 at https://www.jstor.org/stable/pdf/1565576.pdf?refreqid=excelsior:6883fa5c27dda987057bc7e85f3202e9.

Bolanos, F., D. Robinson, D. Wake. 1987. A new species of salamander (genus Bolitoglossa) from Costa Rica. Revista de Biologia Tropical, 35/1: 87-92. Accessed January 29, 2018 at https://revistas.ucr.ac.cr/index.php/rbt/article/view/24167/26054.

Brodie Jr., E., P. Ducey. 1991.

Antipredator Skin Secretions of Some Tropical Salamanders (Bolitoglossa) are Toxic to Snake Predators1
. Biotropica, 23/01: 58-62. Accessed March 04, 2018 at https://www.jstor.org/stable/pdf/2388688.pdf?refreqid=excelsior%3A41b7c95f9e83a91c10ba556195c1c8d2.

Carvalho Brcko, I., M. Steven Hoogmoed, S. Neckel-Oliveira. 2015. Taxonomy and distribution of the salamander genus Bolitoglossa Duméril, Bibron & Duméril, 1854 (Amphibia, Caudata, Plethodontidae) in Brazilian Amazonia. Zootaxa, 3686(4): 401-431. Accessed February 11, 2018 at https://www.researchgate.net/publication/283898288_Taxonomy_and_distribution_of_the_salamander_genus_Bolitoglossa_Dumeril_Bibron_Dumeril_1854_Amphibia_Caudata_Plethodontidae_in_Brazilian_Amazonia.

Cruz, G., L. Wilson, R. McCranie, F. Castaneda. 2008. "The IUCN Red List of Threatened Species" (On-line). Bolitoglossa celaque. Accessed January 29, 2018 at http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T59144A11889323.en.

Ducey, P., E. Brodie, Jr., E. Baness. 1993. Salamander Tail Autotomy and Snake Predation: Role of Antipredator Behavior and Toxicity for Three Neotropical Bolitoglossa (Caudata: Plethodontidae). Biotropica, 25/3: 344-349. Accessed February 25, 2018 at http://www.jstor.org/stable/pdf/2388793.pdf?refreqid=excelsior%3A1aa032f783d332c3ea1d320f381b8b34.

Garcia-Paris, M., G. Parra-Olea, D. Wake. 2008. Description of a new species of the Bolitoglossa subpalmata group (Caudata: Plethodontidae) from Costa Rica. Herpetological Journal, 18: 23-31. Accessed January 29, 2018 at https://ib.berkeley.edu/labs/wake/341_GP,PO,DBW_HerpJ_08.pdf.

Houck, L., S. Arnold. 2003. Reproductive Biology and Phylogeny of Urodela. 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487 USA: CRC Press. Accessed February 25, 2018 at http://www.cnah.org/pdf/88410.pdf.

Jaeger, R. 1984. Agonistic Behavior of the Red-Backed Salamander. Copeia, 1984/2: 309-314. Accessed February 25, 2018 at http://www.jstor.org/stable/1445186?casa_token=dBSach1jIw4AAAAA:7AWije8VzxBTr9zKtolzFZrfEBXnVbj7fTYYubzmeK2D33DDwkz2NT60eJmOoe_Z1B_GZxal9uTOikGKfZH1qMqfYjAJ90gwtUBrRQbfMhWPRx-g7dw&seq=1#page_scan_tab_contents.

Jaeger, R., D. Forester. 1993. Social Behavior of Plethodontid Salamanders. Herpetologica, 49/2: 163-175. Accessed February 25, 2018 at http://www.jstor.org/stable/pdf/3892793.pdf?refreqid=excelsior%3Ab894eeac10685a79ffc0fa45148b5ff2.

Leonardo Meza-Joya, F., C. Andres Hernandez-Jaimes, E. Ramos-Pallares. 2017. A new species of Salamander (Caudata, Plethodontidae, Bolitoglossa) from Serranía de los Yariguíes, Colombia. Zootaxa, 4294/1: 093-111. Accessed January 29, 2018 at https://www.researchgate.net/publication/318466520_A_new_species_of_Salamander_Caudata_Plethodontidae_Bolitoglossa_from_Serrania_de_los_Yariguies_Colombia.

Rovito, S., G. Parra-Olea, D. Lee, D. Wake. 2012. A new species of Bolitoglossa (Amphibia, Caudata) from the Sierra de Juárez, Oaxaca, Mexico. Zookeys, 185: 55-71. Accessed January 29, 2018 at https://zookeys.pensoft.net/articles.php?id=2680.

Schargel, W., J. Garcia-Perez, E. Smith. 2002. A New Species of Bolitoglossa (Caudata: Plethodontidae) from the Cordillera de Merida, Venezuela. Proceedings of the Biological Society of Washington, 115/3: 534-542. Accessed January 29, 2018 at https://www.biodiversitylibrary.org/page/35518901#page/548/mode/2up.

Sessions, S., A. Larson. 1987. Developmental Correlates of genome Size in Plethodontid Salamanders and their Implications for Genome Evolution. Evolution, 41/6: 1239-1251. Accessed April 22, 2018 at http://www.jstor.org/stable/2409090?casa_token=XgdIyExN49MAAAAA:bLH2IACUwo1AWh_xf2tdIHvTJW9nRFYjLj7q3uqCZtHFMz_-a8c4sMa-I9qeHXfX0ta9d649omWpy3JFoob6hI8oPkow-UGtULgC5KSzXUW-z7bw644&seq=1#page_scan_tab_contents.

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Townsend, J., J. Butler, L. Wilson, J. Austin. 2009. A new species of salamander in the Bolitoglossa dunni group (Caudata: Plethodontidae: Bolitoglossinae) from Parque Nacional Montaña de Yoro, Honduras. Salamandra, 45/2: 95-105. Accessed January 29, 2018 at http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.537.1474&rep=rep1&type=pdf.

Vasquez-Almazan, C., S. Rovito. 2004. A New Species of Black Bolitoglossa (Caudata: Plethodontidae) from Guatemala. Journal of Herpetology, 48/4: 518-524. Accessed January 29, 2018 at http://www.bioone.org/doi/full/10.1670/13-170.

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Woodley, S. 2010. Pheromonal Communications in Amphibians. Journal of Comparative Physiology, 196/10: 713-727. Accessed February 25, 2018 at https://link.springer.com/content/pdf/10.1007%2Fs00359-010-0540-6.pdf.