Engystomops petersi

Last updated

Engystomops petersi
Engystomops petersi 2.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Leptodactylidae
Genus: Engystomops
Species:
E. petersi
Binomial name
Engystomops petersi
Jiménez de la Espada, 1872
Synonyms

Physalaemus petersi (Jiménez de la Espada, 1872)
Eupemphix paraensisMüller, 1923
Eupemphix schereriMyers, 1942

Contents

Engystomops petersi (common name: Peters' dwarf frog) is a species of frog in the family Leptodactylidae. It is found in Amazonian Colombia, Ecuador, and Peru. It is morphologically similar to its sibling species, Engystomops freibergi , and for a period the latter was considered to be a junior synonym of Engystomops petersi. Taxonomy and classification of this species is constantly changing due to the continual evolution of behavioral isolation and rapid speciation in the region. There are also records from the Guianas that have not yet been allocated to either species. [2] Divergence of these two species seems to have been driven by behavioural isolation related to male call characteristics more than geographic isolation. [3]

Taxonomy

The genus Engystomops is part of the family Leptodactylid. Previously, the genus Engystomops was grouped in with other Amazonian genera like Eupemphix and Physalaemus. [4] These names are routinely exchanged making it hard to characterize differences among different species. Previously, Eupemphix paraensis, Eupemphix schereri, and Engystomops petersi were considered to be distinct species, however morphological analyses of these frogs revealed that they were conspecifics and synonymous species. [4]  

Description

Engystomops petersi are relatively small frogs. Males measure 21–31 mm (0.83–1.22 in) in snout–vent length and females 25–39 mm (0.98–1.54 in). Dorsal colouration is variable. Skin on the dorsum is warty, bearing small tubercles with scattered larger tubercles. [5] This species lacks maxillary and premaxillary teeth. [4] E. petersi also has terminal phalanges that are T-shaped and two salivary glands known as parotoid glands that are generally visible. The hands and feet of E. petersi are characterized by bulbous fingers in which the first finger is greater in length compared to the second finger. [4]   Their build varies from slender to stocky. They are also distinct from other similar frogs in that some females have concealed eardrums or tympani and males have prominent tympani. [4]

Larval Morphology

The larval morphology of E. petersi has been thoroughly studied and compared to other members of the Engystomops genus. E. petersi larvae are generally perceived to be the largest in size of all Engystomops larvae. [6] Its larval structure is mainly composed of the body, snout, oral disc, vent tube, tail, dorsal fin, ventral fin, and other organs. The length of the larva usually is around 22.7 mm. Its body length comprises a little less than half of its total length. [6] It has a broad snout that is wide and round with nostrils that are slightly discolored on the outer rim. Its oral disc is filled with small papillae arranged rows with various tip lengths and shapes. [6]   The jaw has a dark coloration and is marked by serrations that follow an arc-shaped pattern. E. petersi tadpoles also have a vent tube that is attached to the ventral fin of the body. [6] Their tails are approximately 60% of their entire body length with a narrowly rounded tip. A distinguishing characteristic of E. petersi larvae compared to other Engystomops species is the presence of prominent elliptical paravertebral glands. [6]

The coloration of E. petersi larva has only been reported after preservation. In preservative, its coloration is mainly dark to light brown. Aspotty mesh pattern with speckles around certain regions of the body is also visible. The tail is light brown with speckles all over and the fins are translucent with threadlike markings. [6]

Habitat and Distribution Speciation

Engystomops petersi is a common species that inhabits primary and secondary forests and forest edges. They are terrestrial frogs often found in leaf-litter. They are nocturnal, and prefer humid environments. While they are terrestrial, they breed near water bodies, specifically on the edges of lakes, ponds, and pools. The males sing and send mating calls while floating on their backs in the water. [1] The genus Engystomops is a lineage of frogs located in the Andean foothills of Ecuador, Peru, and Bolivia, extending to the Amazon basin in Brazil. [7] Speciation events of the genus are well studied and typically defined using the study of mitochondrial DNA, mating calls, and cytogenetic variation among different frogs in the area. Engystomops petersi makes up the northwestern clade of the genus Engystomops and was found to be its own species located in northern Peru and Ecuador. [7] Puyo, Ecuador is a hub for Engystomops petersi frogs and has been used for comparative karyotypic analysis with other frog species in the area. Its karyotype is unique compared to other Engystomops species in the area and specifically diverges from the southwestern clade known as E. freibergi located in southern Peru and Brazil. [7]

Genetic Population Structure

Sexual selection has been thought to play a role in evolutionary speciation of Engystomops. Female E. petersi discriminate against certain mating calls from foreign populations and will recognize calls from specific locations. [7] Such behavioral isolation of the species likely led to speciation. The genetic variation between different Engystomops species is also characterized by variations within karyotypes with different banding patterns as well as clade divergence. [7]

Feeding Behavior

E. petersi diet consists exclusively of termites. [8] This is in contrast to Engystompos pustulosus, which has a larger diet breadth compared to the specialized diet of the E. petersi. [8] This species has been observed to feed in groups in some circumstances. [9] In a herpetological study in Bolivia, E. petersi were observed feeding on termites in a semicircular formation. [9] This is one of the few examples of group feeding seen in herpetofauna in the region, which tend to feed on leaf litters on the rainforest floor.

Reproduction

E. petersi's breeding period coincides with the rainy season. [1] The male call consists of a prefix and a "whine" component, and, in some populations only, a third "squawk" component. Eggs are laid in foam nests. [5]

Mating Calls and Female Choice

E. petersi females display preferential mate selection towards males with conspecific calls. The characteristic call of E. petersi consists of two parts. The first part of the advertisement call is known as the prefix. [10] The prefix consists of one or two short bursts of sound at a frequency of about 20-70 ms. The second part of the advertisement call consists of the whine. The whine is a lower-frequency sweeping call that occurs after the prefix. In certain areas E. petersi populations also add a suffix to the end of the whine that occurs at a higher frequency compared to the rest of the call. [10] Within E. petersi populations there has also been divergence in mating call patterns in geographically isolated regions. [10] In three geographically isolated regions in Ecuador, mating calls of E. petersi vary in frequency in different regions, serving as likely evidence for further speciation of E. petersi over time.

Female E. petersi tend to prefer local calls over foreign calls from male conspecifics. [10] They don’t tend to recognize different frequency calls. They also prefer the complex calls that include a suffix at the end compared to the simpler calls with a prefix and whine only. [10] The strong preference for local males serves as evidence of behavioral isolation in this species. This is important for understanding genetic drift, sexual selection, and speciations in the Amazon where genetic drift is so high. The rapid speciation of E. petersi makes it a good subject for analysis of evolutionary patterns in these environments.

Genetic Diversity

E. petersi are known to be in behavioral isolation. Females prefer conspecific chorus calls to calls from other species, a factor leading to their evolution of reproductive isolation. [11] Despite this, a few instances have been found involving reproduction between heterospecifics. This has led to hybrid specification with minimal phenotypic differences between frogs in close geographic proximity. However, E. petersi has general karyotype differences among different species making fertilization and development less likely to succeed. [11] In fact, fertilization crosses with E. magnus and E. selva lead to reduced fertilization rates and overall decrease in fertility. [11] This has been attributed to high variation in chromosome structure, banding pattern, and length between the different species creating unstable karyotypes in future progeny. [11]

Conservation and Threats

E. petersi have been used in conservation studies for the anuran population in the Andes. [12] They are potentially threatened by the invasive species of rainbow trout that has infested the water of the Ecuadorian Andes. Rainbow trout serve as a vector for Saprolegnia diclina, which can effectively transmit this disease to E. petersi tadpoles, increasing their mortality and iltuimately contributing to the decrease of anuran populations in the area. [12] With the increasing number of rainbow trout farms in the area, rainbow trout are a growing potential threat to nearby anuran species.

Habitat loss is also a major concern for E. petersi. The Ecuadorian forests have lost almost 60% of their habitats due to deforestation. [13] There have also been many legal and illegal mining and logging activities that further habitat loss. [13] This is a threat not only to E. petersi but all other biodiversity in the region. Since E. petersi is localized to a comparatively small region, such habitat loss could be especially devastating for this species.

Related Research Articles

<span class="mw-page-title-main">Fletcher's frog</span> Species of amphibian

Fletcher's frog, commonly known as the sandpaper frog or black-soled frog, is a species of nocturnal, terrestrial frog native to eastern Australia. It is primarily found in wet sclerophyll forests along mountain ranges and the coast.

<span class="mw-page-title-main">Northern cricket frog</span> Species of amphibian

The northern cricket frog is a species of small hylid frog native to the United States and northeastern Mexico. These frogs are majorly in grey, green, and brown color with blotching patterns. Many have a brown or orange stripe down the center of their back and a triangular marking on the top of their head. Despite being members of the tree frog family, they are not arboreal. These frogs prefer habitats near the edges of slow-moving bodies of water, and in close proximity to shelter items, like rocks. It has two recognized subspecies, A. c. crepitans and A. c. paludicola.

<i>Dendropsophus ebraccatus</i> Species of amphibian

Dendropsophus ebraccatus, also known as the hourglass treefrog, referring to the golden-brown hourglass shape seen surrounded by skin yellow on its back. Their underbellies are yellow. Their arms and lower legs usually display bold patterns while their upper legs or thighs are light yellow giving them the appearance of wearing no pants. The species name "ebraccata" translates to "without trousers" in Latin.

<i>Dendropsophus marmoratus</i> Species of frog

Dendropsophus marmoratus is a species of frog in the family Hylidae. It is found in the Amazon rainforest and montane forests in the eastern piedmont, in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela. Its natural habitats are subtropical or tropical moist lowland forests, intermittent freshwater marshes, and heavily degraded former forest. "Marmoratus" in Latin means "marble," perhaps referring to the dorsal coloring pattern. It is threatened by habitat loss.

<i>Phyllomedusa trinitatis</i> Species of frog

Phyllomedusa trinitatis is a species of frog in the subfamily Phyllomedusinae. It is found in Venezuela and the island of Trinidad.

<i>Edalorhina perezi</i> Species of frog

Edalorhina perezi is a species of frog in the family Leptodactylidae. It is one of the only two species in the genus Edalorhina in the family Leptodactylidae. This species is diurnal and terrestrial. During mating season both female and male frogs gather around treefall pools. It is found in Brazil, Colombia, Ecuador, and Peru, and possibly Bolivia. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical moist montane forests, and freshwater marshes. The species listed as least concern on the IUCN Red List and the population is stable.

<i>Lithodytes</i> Genus of amphibians

Lithodytes is a genus of frogs in the family of Leptodactylidae. It is monotypic, being represented by the single species, Lithodytes lineatus, also commonly known as the gold-striped frog or painted antnest frog. It is found in tropical South America where it lives in humid forests among the leaf litter. These frogs build foam nests at the edge of temporary pools, and the tadpoles develop within these. The frogs also associate with certain leafcutter ants and breed inside their nests without being attacked by the ants.

Noblella lochites, also known as Ecuador leaf frog, is a species of frog in the family Strabomantidae. It is found on the Amazonian slopes of the Andes and Cordillera del Cóndor and the Cordillera de Cutucú in Ecuador and Peru; the Peruvian record has been disputed, although it is nevertheless expected that the species occurs in Peru.

<i>Physalaemus barrioi</i> Species of frog

Physalaemus barrioi is a species of frog in the family Leptodactylidae. It is endemic to Serra do Bocaina in São Paulo state, Brazil. The specific name barrioi honors Avelino Barrio, a Spanish botanist and zoologist who lived in Argentina. However, the common name Bocaina dwarf frog has been proposed for it.

<i>Engystomops coloradorum</i> Species of amphibian

Engystomops coloradorum, also known as Colorado dwarf frog, is a species of frogs in the family Leptodactylidae. It is endemic to the Pacific lowlands and foothills of the Andes in the Pichincha and Santo Domingo de los Tsáchilas Provinces, Ecuador.

Physalaemus deimaticus is a species of frog in the family Leptodactylidae. It is endemic to Brazil and only known from its type locality in Jaboticatubas, Serra do Cipó, Minas Gerais. The specific name deimaticus is derived from Greek deimos fror "fear" and refers to the defensive display of this frog, probably aimed at scaring predators. Common names Jaboticatubas dwarf frog and frightening foam froglet have been coined for it.

Engystomops pustulatus is a species of frog in the family Leptodactylidae. It is known with certainty from western Ecuador, whereas the status of Peruvian records is ambiguous as they may refer to an undescribed species or possibly Engystomops puyango. Nevertheless, given that E. pustulatus is now known from Huaquillas in southern Ecuador, near the Peruvian border, it is likely to be found in Peru too.

<span class="mw-page-title-main">Túngara frog</span> Species of amphibian

The Túngara frog is a species of frog in the family Leptodactylidae. It is a small nocturnal terrestrial frog found in Mexico, Central America, and the northeastern regions of South America.

<i>Leptodactylus discodactylus</i> Species of frog

Leptodactylus discodactylus is a species of frog in the family Leptodactylidae. It is found in the Amazonian Bolivia, Brazil, Peru, Ecuador, and Colombia.

A mating call is the auditory signal used by animals to attract mates. It can occur in males or females, but literature is abundantly favored toward researching mating calls in females. In addition, mating calls are often the subject of mate choice, in which the preferences of one gender for a certain type of mating call can drive sexual selection in a species. This can result in sympatric speciation of some animals, where two species diverge from each other while living in the same environment.

<i>Engystomops</i> Genus of amphibians

Engystomops is a genus of frogs in the family Leptodactylidae. They are known commonly as foam frogs or túngara frogs, though the latter name most commonly refers to Engystomops pustulosus. They are native to the Americas from southern Mexico south to the Amazon Basin.

Engystomops freibergi is a frog native to the Amazonian Brazil, southeastern Peru, and Amazonian Bolivia. For a while, it was considered to be a synonym of Engystomops petersi, its sibling species, but its species status was resurrected in a study published in 1998. Nevertheless, these two species have also been mixed in later studies, and there are records from the Guianas that have not yet been allocated to either species. Divergence of these two species seems to have been driven by behavioural isolation related to male call characteristics more than geographic isolation.

Dwarf frog may refer to:

<span class="mw-page-title-main">Leiuperinae</span> Subfamily of amphibians

The Leiuperinae are a subfamily of frogs in the family Leptodactylidae. Over 90 species are in five genera. The distribution of this subfamily is from southern Mexico to the Central America and much of South America.

<span class="mw-page-title-main">Evidence for speciation by reinforcement</span> Overview article

Reinforcement is a process within speciation where natural selection increases the reproductive isolation between two populations of species by reducing the production of hybrids. Evidence for speciation by reinforcement has been gathered since the 1990s, and along with data from comparative studies and laboratory experiments, has overcome many of the objections to the theory. Differences in behavior or biology that inhibit formation of hybrid zygotes are termed prezygotic isolation. Reinforcement can be shown to be occurring by measuring the strength of prezygotic isolation in a sympatric population in comparison to an allopatric population of the same species. Comparative studies of this allow for determining large-scale patterns in nature across various taxa. Mating patterns in hybrid zones can also be used to detect reinforcement. Reproductive character displacement is seen as a result of reinforcement, so many of the cases in nature express this pattern in sympatry. Reinforcement's prevalence is unknown, but the patterns of reproductive character displacement are found across numerous taxa, and is considered to be a common occurrence in nature. Studies of reinforcement in nature often prove difficult, as alternative explanations for the detected patterns can be asserted. Nevertheless, empirical evidence exists for reinforcement occurring across various taxa and its role in precipitating speciation is conclusive.

References

  1. 1 2 3 IUCN SSC Amphibian Specialist Group (2018). "Engystomops petersi". IUCN Red List of Threatened Species . 2018: e.T57270A85893490. doi: 10.2305/IUCN.UK.2018-1.RLTS.T57270A85893490.en . Retrieved 17 November 2021.
  2. Frost, Darrel R. (2014). "Engystomops petersi Jiménez de la Espada, 1872". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 1 March 2014.
  3. Funk, W. C.; Cannatella, D. C.; Ryan, M. J. (2009). "Genetic divergence is more tightly related to call variation than landscape features in the Amazonian frogs Physalaemus petersi and P. freibergi". Journal of Evolutionary Biology. 22 (9): 1839–1853. doi:10.1111/j.1420-9101.2009.01795.x. PMID   19583696.
  4. 1 2 3 4 5 Lynch, John D. (1970). "Systematic Status of the American Leptodactylid Frog Genera Engystomops, Eupemphix, and Physalaemus" . Copeia. 1970 (3): 488–496. doi:10.2307/1442276. ISSN   0045-8511. JSTOR   1442276.
  5. 1 2 Funk, W. C.; Angulo, A.; Caldwell, J. P.; Ryan, M. J.; Cannatella, D. C. (2008). "Comparison of morphology and calls of two cryptic species of Physalaemus (Anura: Leiuperidae)". Herpetologica. 64 (3): 290–304. doi:10.1655/08-019.1. S2CID   40767898.
  6. 1 2 3 4 5 6 do Nascimento, Filipe A. C.; de Sá, Rafael O.; Garcia, Paulo C. de A. (October 2022). "Larval morphology of Amazonia foam‐nesting frogs of the genus Engystomops (Anura: Leptodactylidae: Leiuperinae)" . Journal of Morphology. 283 (10): 1299–1317. doi:10.1002/jmor.21503. ISSN   0362-2525. PMID   35971644. S2CID   251592075.
  7. 1 2 3 4 5 Targueta, C. P.; Rivera, M.; Souza, M. B.; Recco-Pimentel, S. M.; Lourenço, L. B. (2010-03-01). "Cytogenetic contributions for the study of the Amazonian Engystomops (Anura; Leiuperidae) assessed in the light of phylogenetic relationships". Molecular Phylogenetics and Evolution. 54 (3): 709–725. doi: 10.1016/j.ympev.2009.10.018 . ISSN   1055-7903. PMID   19861165.
  8. 1 2 Narváez, Andrea E.; Ron, Santiago R. (December 2013). "Feeding Habits of Engystomops pustulatus (Anura: Leptodactylidae) in Western Ecuador" . South American Journal of Herpetology. 8 (3): 161–167. doi:10.2994/SAJH-D-13-00012.1. ISSN   1808-9798. S2CID   86350285.
  9. 1 2 Powell, Randy L.; Eversole, Cord B.; Lizarro, Dennis; Crocker, Ashton V.; Calderón Vaca, Gonzalo; Surovic, Elizabeth A. (2020-09-11). "Bothrops taeniatus Wagler, 1824 (Serpentes, Viperidae): additional country record and list of voucher specimens for Bolivia" (PDF). Check List. 16 (5): 1143–1147. doi: 10.15560/16.5.1143 . ISSN   1809-127X. S2CID   225242938.
  10. 1 2 3 4 5 Guerra, Mónica A.; Ron, Santiago R. (2008). "Mate choice and courtship signal differentiation promotes speciation in an Amazonian frog". Behavioral Ecology. 19 (6): 1128–1135. doi: 10.1093/beheco/arn098 . ISSN   1465-7279.
  11. 1 2 3 4 Trillo, Paula A.; Narvaez, Andrea E.; Ron, Santiago R.; Hoke, Kim L. (2017-04-07). "Mating patterns and post-mating isolation in three cryptic species of the Engystomops petersi species complex". PLOS ONE. 12 (4): e0174743. doi: 10.1371/journal.pone.0174743 . ISSN   1932-6203. PMC   5384746 . PMID   28388628.
  12. 1 2 Martín-Torrijos, Laura; Sandoval-Sierra, Jose Vladimir; Muñoz, Jesús; Diéguez-Uribeondo, Javier; Bosch, Jaime; Guayasamin, Juan M. (2016-01-01). "Rainbow trout (Oncorhynchus mykiss) threaten Andean amphibians". Neotropical Biodiversity. 2 (1): 26–36. doi: 10.1080/23766808.2016.1151133 . hdl: 10261/158670 . S2CID   49732292.
  13. 1 2 "New report reveals northern Ecuadorian region has lost 61 percent of forests". Mongabay Environmental News. 2019-09-04. Retrieved 2022-11-09.