Sunday 16 January 2022

Pristimantis gretathunbergae: A new species of Rain Frog from Panama, named in honour of Swedish climate activist Greta Thunberg.

Tropical forests are noted for their high biodiversity and species richness, with a wide range of ecological variables which favour the emergence of numerous species with limited distributions among some groups of Animals and Plants. One such group are the Anurans (Frogs), of which very high species numbers are found in many tropical regions. One particularly notable group of Frogs are the Rain Frogs, Pristimantis spp., of the Caribbean and Central and South America. The genus Pristimantis currently contains at least 574 species (possibly the highest number of species in any Vertebrate genus), distributed primarily in Tropical Andes of Colombia, Ecuador, and Peru, yet is considered to be understudied, with many more species likely to exist (124 species have been described within the past decade), and many of the currently described species having uncertain relationships to other members of the group. The species richness within this genus is driven by its ability to breed away from water, enabling them to colonise environments closed to other Frogs, while the taxonomic uncertainty is caused by the high variability of many species, with members of different species often resembling one-another than they do members of their own species. This is slowly being unravelled with modern genetic methods, although this is showing an even greater diversity within the genus than previously supposed, apparently caused by a recent radiation event, resulting in the genus now comprising 7.4% of all known Anuran species, and 6.7% of all Lisamphibians.

In a paper published in he journal ZooKeys on 10 January 2022, a team of scientists led by Konrad Mebert of the Programa de Pós-graduação em Zoologia at the Universidade Estadual de Santa Cruz, Global Biology, and Los Naturalistas, describe a new species of Rain Frog from Panama.

The new species is named Pristimantis gretathunbergae, in honour of Swedish climate activist Greta Thunberg, for her 'authentic voice that exposes the motivations behind the diplomatic curtain of politicians and business stakeholders'. The species is described upon the basis of a series of specimens collected on the top of Cerro Chucantí in the Maje Mountains of Darién Province, Panama, though the species was later shown to be found across a wider area.

Colouration in life of specimens of Pristimantis gretathunbergae sp. nov. and Pristimantis cruentus from eastern Panama. (A) Holotype male (MHCH 3082), Cerro Chucantí. (B) Paratype female (SMF97520), Cerro Chucantí. (C) :eft, paratype female (MHCH 3081), right Pristimantis cruentus female (MHCH3034). (D) Female from Cerro Chucantí, not collected. (E) Female (MHCH3115) La Javillosa. (F) Female, Cerro La Javillosa, Ambroya, Maje Mountain Range (SMF97517). (G) Female (MHCH3079), Rio Tuquesa. Coloured lines point to some diagnostic characters as follow: red: blackish iris; yellow: single spine-like tubercle; turquoise: light-coloured upper lip; pink: cream, yellow to red groin. Mebert et al. (2022).

Pristimantis gretathunbergae has a slightly blotchy brown colouration, more notable on the darker upper surface than the paler lower side, this is accentuated by a scattering of tubercles on the dorsal surface. The tympanum (ear) is invisible, or at least hard to distinguish, the snout is short and slightly rounded, and the upper eyelid has a spine-like tubercle. Each vomer (bone in the roof of the mouth, behind the jaw, bears 5-10 teeth. The groin and inner thighs are white, yellow or orange-red, some with flecks matching the dorsal ground colour or red. The iris is black, though some individuals have a very dark red iris, or a black iris with red-golden speckling.

Habitat, mating, and parental care in females of Pristimantis gretathunbergae from Cerro Chucantí. (A) Habitat on Cerro Chucantí at about 1300 m above sealevel. (B) Understory Bromeliad with a Pristimantis gretathunbergae in situ (blue line) and zoomed in on inset (MHCH 3115). (C) Amplectant pair on axillary part of Bromeliad leaf (not collected). (D) Same female after amplexus guarding eggs. (E) Female of Pristimantis gretathunbergae taking care of its eggs with a male Pristimantis cruentus holding on the female in reverse position (not collected). (F) Female with eggs about to hatch, note the transparency of the egg membrane (not collected). Mebert et al. (2022).

Wider sampling, combined with genetic profiling of collected specimens, found that Pristimantis gretathunbergae is present across much of eastern Panama, and could potentially be present in adjacent areas of Colombia. The species was found in the Darien Mountains within Embera Comarca and the Maje Mountains within Darien and Panama Provinces, including the type locality at Cerro Chucantí. The species was also found to be present in parts of western Panama, including the Piedras-Pacora Mountains in Panama Province, and Cerro Bruja in Colon Province, both within the Chagres National Park. Beyond the Panama Canal Pristimantis gretathunbergae is present in the Altos del Maria region of the Gaita Hills in Panama Oeste Province, and in the region of El Cope within the Omar Torrijos National Park in Coclé Province.

Pristimantis gretathunbergae has been recorded at altitudes of between 718 and 1439 above sealevel, predominantly within montane forest (cloud forest consisting predominantly of trees covered with Moss and a large variety of understory and midstory Bromeliads). During the nights the Frogs were found from 50 cm to 3 m above the ground on tree bark and in the Bromeliad foliage; in the day they hid between Bromeliad leaves. In the rainy season the males make a sporadic 'chack' call. Females have been observed guarding clusters of eggs in Bromeliads and on Moss-covered tree branches. The species has not been observed eating, but other members of the genus Pristimantis feed primarily on small Arthropods, such as Ants, Orthopterans, and Spiders.

Despite its widespread distribution, Mebert et al, believe that Pristimantis gretathunbergae is likely to face decline of many populations due to habitat destruction caused by anthropogenic pressure. Only a few areas where the species is found are within National Parks or other protected areas, and the species is known only from patches of primary forest and slightly disturbed areas, many of which are surrounded by agriculture and pastures. The species is also found close to areas where Amphibian populations have been decimated by the Chytrid Fungus, Batrachochytrium dendrobatidis, which the species must also be presumed to be threatened by. For this reason, Mebert et al. recommend that Pristimantis gretathunbergae be classified as Vulnerable under the terms of the International Union for the Conservation of Nature’s Red List of Threatened Species

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