Pristimantis erythros: A new species of Rain Frog from the high paramo of southern Ecuador.

The Andes Mountains of South America are form one of the most biologically diverse regions of the Earth, due to the huge range of habitats found on the slopes of the mountains as they cross a vast span of climatic zones. The paramo ecosystem is found on the high slopes of the northern Andes between northern Peru and Venezuela, with outliers in the mountains of Panama and Costa Rica in Central America. This ecosystem is found above the forest-line (around 3000 m in this area), but below the permanent snow-line, and is dominated by bush-grasses, rosette and cushion plants, mycrophyllous and dwarf shrubs, and geophytes. Amphibians are generally rare in high-altitude environments, but the paramo is home to a wide variety of Frogs, including many insular species with very limited ranges, cut off from other areas of similar environments on separate mountains.

In a paper published in the journal ZooKeys on 20 April 2018, Juan Sánchez-Nivicela of the Laboratorio de Herpetología at the Museo de Zoología de la Universidad del Azuay, and the Instituto Nacional de Biodiversidad, Elvis Celi-Piedra and Valentina Posse-Sarmiento, also of the Laboratorio de Herpetología at the Museo de Zoología de la Universidad del Azuay, Verónica Urgiles, again of the Laboratorio de Herpetología at the Museo de Zoología de la Universidad del Azuay, the Instituto Nacional de Biodiversidad, and of the Department of Biology at the University of Central Florida, Mario Yánez-Muñoz, also of the Instituto Nacional de Biodiversidad, and of the Museo de Zoología at the Pontificia Universidad Católica del Ecuador, and of the Diego Cisneros-Heredia, once again of the Instituto Nacional de Biodiversidad, and of the Instituto de Zoología Terrestre & Museo de Zoología, Instituto Biósfera and Instituto de Geografía, at the Universidad San Francisco de Quito, and of the Department of Geography at King’s College London, describe a new species of Frog from the high paramo of southern Ecuador.

The new species is placed in the genus Pristimantis, the most specieous genus of terrestrial vertebrates known with almost 500 species commonly known as Rain Frogs, and given the specific name erythros, meaning red. This species is a distinctive red colour, with a short snout and granular skin on its head and back. Females of this species are larger than the males, with examined female specimens reaching 38.8–42.6 mm, compared to 36.7–37.0 mm in the males.

Lateral, dorsal and ventral views of living specimens of Pristimantis erythros. Left, male; right, female. Sánchez-Nivicela (2018).

The species was found in an area of paramos on the Cajas Massif, at altitudes of 3450–3500 m, mainly in terrestrial Bromeliads (Puya hamata) and Grasses (Neurolepis villosa), near to small streams. Given the small are in which the Frog were found, and the fact that this area was not in a protected area, Sánchez-Nivicela et al. recomend that the species be listed as Critically Endangered under the terms of the International Union for the Conservation of Nature’s Red List of Threatened Species.

 Habitat of Pristimantis erythros in type locality. Sánchez-Nivicela (2018).

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Nyctibatrachus mewasinghi: A new species of Night Frog from the Western Ghats of India.

Night Frogs, Nyctibatrachus spp., are a groups of robust-bodied Frogs found only in the Western Ghats mountain range of southwest India. They get their name from their dark colouration and nocturnal habits. They were formerly placed in the True Frog family, Ranidae, but are now recognised as belonging to a distinct family of their own, the Nyctibatrachidae, which includes only one other Frog, the Sri Lankan Wart Frog, Lankanectes corrugatus.

In a paper published in the Journal of Threatened Taxa on 26 December 2017, Keerthi Krutha of the Wildlife Information Liaison Development Society, Neelesh Dahanukar of the Indian Institute of Science Education and Research, and the Systematics, Ecology and Conservation Laboratory at the Zoo Outreach Organization, and Sanjay Molur, also of the Systematics, Ecology and Conservation Laboratory at the Zoo Outreach Organization,describe a new species of Night Frog from the Malabar Wildlife Sanctuary, in Kerela State, India.

The new species is named Nyctibatrachus mewasinghi, in honour of Mewa Singh of the University of Mysore, the Institution of Excellence, and the Jawaharlal Nehru Centre for Advanced Scientific Research. The species is small for a Night Frog, reaching 21-23 mm in length as adults, and grayish brown in colour with a lighter underside. The Frogs were found at a single location, a drainage stream near the Peruvannamuzhi Dam.

Nyctibatrachus mewasinghi, female speciemen. Krutha et al. (2018).

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Hypogeophis pti: A new species of Caecilian from Praslin Island, the Seychelles.

Caecilians are limbless burrowing Amphibians found in tropical regions of Asia, Africa and South America. They resemble Earthworms, with circular folds on their skin which make them look segmented and skin covering their eyes (though they can see). Unlike snakes they have greatly reduced or even absent tails with their anus close to or at the tips of their bodies. Caecilians are predatory with a well developed sense of smell. Most Caecilians are found on continents; island dwelling species are very rare in this group. However one island group they have colonised are the tropical Seychelles in the Indian Ocean, where six species have been described to date. Four of these six species, Hypogeophis rostratus, Grandisonia alternans, Grandisonia larvata, and Grandisonia sechellensis, are found across several islands, and appear to be tolerant of a wide range of habitats, while the remaining two, Praslinia cooperi, and Hypogeophis brevis, appear to be restricted to habitats above 350 m, and are found on the two islands of the Seychelles that reach over 400 m, Mahé and Silhouette, with Hypogeophis brevis only ever recorded from Mahé.

In a paper published in the journal Zootaxa on 6 October 2017, Simon Maddock of the Department of Life Sciences at The Natural History Museum, Department of Genetics, Evolution and Environment at University College London, and the School of Biology, Chemistry and Forensic Science at the University of Wolverhampton, Mark Wilkinson, also of the Department of Life Sciences at The Natural History Museum, Ronald Nussbaum of the Museum of Zoology and Department of Ecology and Evolutionary Biology at the University of Michigan, and David Gower, again of the Department of Life Sciences at The Natural History Museum, describe a new species of Caecillian from Praslin Island in the Seychelles.

The new species is named Hypogeophis pti, where 'pti' means small in Seychellois Creole (deriving from the French 'petit'). The species is notably smaller than any other Caecilian from the Seychelles, with less than 70 vertebrae and a maximum recorded length of 116 mm. This species is grey brown in colour, lighter on the underside, with eyes visible as dark spots. The species was found at three locations, around the village of Ma Katrine, and at Fond Peper and Glacis Noir in the Praslin National Park. All specimens were found at altitudes of between 170 and 350 m, in slightly acid silty clay loam or sandy loam soils beneath dense layers of dried leaves.

Live specimen of Hypogeophis pti from Fond Peper in thr Praslin National Park. Maddock et al. (2017).

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Scinax onca: A new species of Treefrog from Brazil.

Treefrogs of the genus Scinax are found from from Mexico in the North to central Argentina and Uruguay in the South. Over 70 species of this genus have been described,including 28 species from Amazonia, making it one of the largest genera of Treefrogs, with many undescribed species still thought to be present in less well explored areas. One such area is the Purus-Madeira Interfluve (area between the Purus and Madiera rivers, both tributaries of the Amazon), of Amazonas State in Brazil, where seven putative undescribed species are thought to be present. This area is currently crossed by an abandoned section of highway, though there have been recent plans to redevelop this road, raising concerns about logging and habitat loss, a major cause of species decline and loss for a variety of groups, including Treefrogs.

In a paper published in the journal ZooKeys on 4 October 2017, Miquéias Ferrão of the Programa de Pós-Graduação em Ecologia at the Instituto Nacional de Pesquisas da Amazônia, Jiří Moravec of the Department of Zoology at the National Museum in Prague, Rafael de Fraga, also of the Programa de Pós-Graduação em Ecologia at the Instituto Nacional de Pesquisas da Amazônia, Alexandre Pinheiro de Almeida of the Programa de Pós-Graduação em Zoologia at the Universidade Federal do Amazonas, Igor Luis Kaefer of the Instituto de Ciências Biológicas, also at the Universidade Federal do Amazonas, and Albertina Pimentel Lima of the Coordenação de Biodiversidade at the Instituto Nacional de Pesquisas da Amazônia, describe a new species of Scinax from the middle to southern part of the Purus-Madeira Interfluve.

The new species is named Scinax onca, where 'onca' refers to the Jaguar, Pantera onca, which was encountered numerous times during fieldwork in the Purus-Madeira Interfluve, and to the blotchy pattern of the species. Females of the species are larger than the males, reaching 35.5−40.4 mm, compared to 31.3−34.5 mm, and are variable in colouration, though generally brown and blotchy, and in addition are capable of changing colour to some extent, generally becoming darker and more blotchy when disturbed.

Colour in life of Scinax onca from the Purus-Madeira Interfluve, Brazilian Amazonia. (A)–(B), adult male from the kilometre 350 of the BR-319 highway, State of Amazonas, (C)–(D) adult female from municipality of Porto Velho, State of Rondônia, (E)–(F) adult female from the Floresta Estadual Tapauá Reserve, municipality of Tapauá, State of Amazonas. Photographs (A)–(D) and (F) were taken after transport of the specimens to the camp, while the image of (E) was taken immediately in the field. Ferrão et al. (2017).

The species was found at four localities, two in areas of closed forest with emergent trees (taller trees that rise above the tree canopy) in the central part of the Interfluve and two areas of open lowland rainforest with frequent Palm Trees in the southern part. They were encountered near temporary ponds following periods of heavy rain, where the males gathered on nearby plants to sing. Tadpoles of the species are ovoid in dorsal view, triangular in lateral view, and silvery-green in colour with large dark brown spots.

 Tadpole of Scinax onca from the middle Purus-Madeira Interfluve. Specimen collected at kilometre 350 of the BR-319 highway, municipality of Beruri, State of Amazonas, Brazil. From top to bottom: dorsal, ventral, and lateral views of preserved tadpole in developmental Stage 37. Scale bar 5 mm. Ferrão et al. (2017).

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Pristimantis prometeii: A new species of Rain Frog from the cloud forests of El Oro in southern Ecuador.

The tropical forests of Central and South America are home to almost half of the known species of Amphibians, and since about a quarter of these species have been described in the past decade, this is likely to be a severe under-estimation of the true diversity of Amphibians in these forests. The largest group of Amphibians in these American tropical forests is the Brachycephaloidea, a group of Frogs with an entirely terrestrial life-cycle, laying eggs in moist habitats, which develop directly into small Froglets and missing out on the Tadpole stage altogether. About half of the described Brachycephaloidians are included in the most specieous genus of terrestrial vertebrates known, Pristimantis, members of which are commonly known as Rain Frogs, which contains almost 500 species.

In a paper published in the journal ZooKeys on 21 July 2016, Paul Székely of the Faculty of Natural and Agricultural Sciences at Ovidius University Constanţa and the Departamento de Ciencias Naturales at the Universidad Técnica Particular de Loja, Dan Cogălniceanu, also of the Faculty of Natural and Agricultural Sciences at Ovidius University Constanţa and of the Universidad Nacional de Loja, Diana Székely, again of the Faculty of Natural and Agricultural Sciences at Ovidius University Constanţa and the Departamento de Ciencias Naturales at the Universidad Técnica Particular de Loja, and of the Laboratory of Fish and Amphibian Ethology at the University of Liège, abd Nadia Páez and Santiago Ron of the Museo de Zoología at the Pontificia Universidad Católica del Ecuador, describe a new species of Robber Frog from the cloud forests of El Oro in southern Ecuador.

The new species is named Pristimantis prometeii, which refers to the Prometeo program of Secretaría de Educación Superior, Ciencia, Tecnología e Innovación of the Republic of Ecuador, through which Dan Cogălniceanu and Paul Székely received funding for their research in southern Ecuador. The Frogs are brown or green in colour with variable blotchy markings. Adult females reach 29.9–37.6 mm in length, males 20.4–24.9 mm.

Pristimantis prometeii, female specimen. Székely et al. (2016).

The species was found at three locations in the Reserva Buenaventura, at altitudes of between 878 and 1082 m. The species was observed in September in 2014 and 2015, generally after rain at night, when they could be found on leaves close to the forest floor (10-100 cm above the ground).

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Eleutherodactylus beguei: A new species of Grass Frog from Guantánamo Province in southeast Cuba.                                          Small Grass Frogs are found across Cuba. Until 2012 these were all placed within a single species, Eleutherodactylus varleyi, but it was...

Robber Frogs from the mountains of western Mexico.                                                                         Robber Frogs of the genus Eleutherodactylus are found from Texas to Guatemala and Belize and across the islands of the Caribbean. The genus was formerly the most specious of any genus of Vertebrate Animals (i.e. it contained more species than any other...

A new cryptic species of Microhylid Frog from Espírito Santo State, Brazil.                      Cryptic species are species which resemble one-another physically, and which cannot generally be separated using traditional taxonomic methodology, but which are nevertheless genetically and reproductively isolated. Genetic studies of many groups...

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Eleutherodactylus beguei: A new species of Grass Frog from Guantánamo Province in southeast Cuba.

Small Grass Frogs are found across Cuba. Until 2012 these were all placed within a single species, Eleutherodactylus varleyi, but it was subsequently shown that many populations across the southeast of the island belonged to a second, cryptic species, Eleutherodactylus feichtingeri, which resembles Eleutherodactylus varleyi in appearance but which has a different call, and which subsequently shown to be genetically distinctive. Such cryptic species have profound implications for conservation, as apparent healthy species, with large populations and wide distributions can be shown to be groups of less widely distributed species, each with smaller, localized populations and different conservation needs.

In a paper published in the journal Solenodon in February 2015, Luis Díaz of the Museo Nacional de Historia Natural de Cuba and Blair Hedges of the Department of Biology at Pennsylvania State University describe a new species of Grass Frog from Pine Forests in the Humboldt National Park in Guantánamo Province in southeast Cuba.

The new species is named Eleutherodactylus beguei, in honour of Gerardo Begué Quiala, an expert on the biodiversity of the Humboldt National Park. As with Eleutherodactylus feichtingeri this species was initially detected due to its distinctive call, then demonstrated to be a separate species by genetic analysis. Eleutherodactylus beguei is smaller than the two previously described species with males reaching only 12.3-14.2 mm in length, compared to a maximum of 17.4 mm for Eleutherodactylus feichtingeri and a maximum of 18.5 mm for Eleutherodactylus varleyi. Only a singe female Eleutherodactylus beguei, was discovered, this was 15.2 mm in length, and mated with one of the males and produced a clutch of 10 ivory white eggs, 3.5-3.7 mm in diameter. Surprisingly this is a larger clutch size than recorded in either of the other two Grass Frog species, despite the smaller size of the adults, with 3-4 eggs more typical. The female also called prior to laying her eggs, which is unusual in Frogs, but which has been recorded in members of the genus Eleutherodactylus before.

Eleutherodactylus beguei, male specimen perching on horizontal leaf from which it was calling. Díaz and Hedges (2015).

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Cryptic diversity in West African Torrent Frogs.                                                                           The West African Torrent Frog, Odontobatrachus natator, is found in fast moving streams and waterways in the forests of Guinea, Sierra Leone Liberia, and western Côte d’Ivoire, part of the Upper Guinean...

Robber Frogs from the mountains of western Mexico.

Robber Frogs of the genus Eleutherodactylus are found from Texas to Guatemala and Belize and across the islands of the Caribbean. The genus was formerly the most specious of any genus of Vertebrate Animals (i.e. it contained more species than any other Vertebrate...

The enigmatic Pleistocene Amphibians of Okinawa Island.                                              In the late 1960s and early 1970s a series of anthropological excavations were carried out at Minatogawa Fissure on southern Okinawa Island, producing a number of Late Pleistocene Human...

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Robber Frogs from the mountains of western Mexico.

Robber Frogs of the genus Eleutherodactylus are found from Texas to Guatemala and Belize and across the islands of the Caribbean. The genus was formerly the most specious of any genus of Vertebrate Animals (i.e. it contained more species than any other Vertebrate genus), but a recent review split it into several different genera, and divided the remaining members of the genus into five subgenera; Syrrhophus, which includes species from North and Central America as well as from Cuba, and four other subgenera from Caribbean Islands.

In a paper published in the journal ZooTaxa on 28 January 2015, Jacobo Reyes-Valasco of the Department of Biology at the University of Texas at Arlington, Ivan Ahumada-Carrillo of the Centro Universitario de Ciencias Biológicas y Agropecuarias, Timothy Burkhardt of Tucson, Arizona and Thomas Devitt of the Department of Integrative Biology at The University of Texas at Austin, describe two new species of Eleutherodactylus from the mountains of Jalisco and Colima States in western Mexico.

The first new species is named Eleutherodactylus grunwaldi, in honour of the German-Mexican naturalist Christoph Grünwald who collected the first specimen of this species. The species is described from nine adult males and a young adult of indeterminate sex collected in the Sierra de Manantlán in Colima and Jalisco States. These are large for members of the genus Eleutherodactylus, with the adult males reaching 28.4 – 32.4 mm in length. They have smooth skin, dark grey with a blotchy green and yellow pattern on their backs and a white underside; their eyes are copper green.

Adult male Eleutherodactylus grunwaldi collected at an altitude of 1329 m in the Municipality of Minatitlán in Colima State, Mexico. Reyes-Valasco et al. (2015).

The species was found living on limestone outcrops in deciduous tropical Pine-Oak forests, at altitudes of 1300-2000 in the Sierra de Manantlán Biosphere Reserve in Colima, but as low as 800 m in the Grutas de Toxín in Jalisco. It is likely that it is more widely distributed in the Sierra de Manantlán and may also be present within the Sierra de Cacoma and Sierra de Talpa. Most of the specimens were collected at the start of the rainy season (i.e. June to August) when the males were calling, though one specimen was collected from a cave in the dry season (February), where other members of the species were also observed. The Sierra de Manantlán Biosphere Reserve is increasingly threatened by iron ore mining, which is known to have destroyed important localities for other species in the area.

The first location where Eleutherodactylus grunwaldi collected in the Municipality of Minatitlán in Colima State, Mexico. Reyes-Valasco et al. (2015).

The second new species described is named Eleutherodactylus wixarika, in honour of the Wixárika (or Huicholes) people, who formerly occupied the states of Nayarit, Jalisco, Zacatecas, Durango and San Luis Potosí, but who are now restricted to the Sierra Huichol Mountains of Jalisco State, where the species was discovered. The species is described from three males collected at Bajío de los Amoles in the Municipality of Mezquitic. These are 21.2 – 24.5 mm in length and red or reddish orange in colour with dark green, brown or black blotches and a grey underside with white spots.

Male specimen of Eleutherodactylus wixarika collected at an altitude of 2467 m at Bajío de los Amoles in the Municipality of Mezquitic. Reyes-Valasco et al. (2015).

All of the specimens were collected on a single day in July (at the beginning of the rainy season), when they were calling. Although collected only from a single location in the Sierra Huichol Mountains it is likely that this species is also found in other mountain ranges in Jalisco, Zacatecas, Nayarit and Durango states. However the area where the species was found contains some of the last remaining old growth forest in the Sierra Madre Occidental (only about 0.65% of the original forest of this region remains), and this forest is under threat from logging, mining, conversion to agriculture and the activities of drug cartels, all of which present a threat to both the wildlife of the region and the traditional lifestyle of the Wixárika people.

Locality where Eleutherodactylus wixarika collected at Bajío de los Amoles in the Municipality of Mezquitic. Reyes-Valasco et al. (2015).

See also…

 The enigmatic Pleistocene Amphibians of Okinawa Island.

In the late 1960s and early 1970s a series of anthropological excavations were carried out at Minatogawa Fissure on southern Okinawa Island, producing a number of Late Pleistocene Human...

A new species of Fanged Frog from Sulawesi.

Fanged Frogs, Limnonectes spp., are unique among Frogs in that the males are typically larger than the females, and frequently fight for territories, the females then mating with the males perceived as having the...

A new species of Treefrog from Madagascar.

Treefrogs of the genus Boophis are found in Madagascar and the Comoros Islands, reaching maximum diversity in the rainforests of eastern Madagascar. There are over 70 species in the genus, most of them being fairly recent discoveries. The genus is split into two subgenera, Boophis, which breeds...

 

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A new species of Caecilian from Brazil.

Caecilians are tropical Amphibians only distantly related to Frogs and Salamanders. They have highly modified bodies, having lost their limbs and taken on a worm-like soil dwelling lifestyle with a body covered in ring-shaped folds of skin called annuli, which resemble the segments of Annelid Worms, which they resemble closely and are often mistaken for, though a typical vertebrate jaw and a mouth full of sharp teeth reveals their true nature. Members of the South American genus Microcaecilia have their eyes covered over by a layer of bone, further increasing their resemblance to Worms.

In a paper published in the journal Zootaxa on 13 January 2015, MarkWilkinson of the Department of Life Sciences at The Natural History Museum and Marta Maria Antoniazzi and Carlos Jared of the Laboratório de Biologia Celular at Instituto Butantan describe a new species of Microcaecilia from the Área de Proteção Ambiental in Pará State, Brazil.

The new species is named Microcaecilia butantan in honour of Instituto Butantan. The species is described from one female and three male specimens, dug up at a Cupuaçu, Theobroma grandiflorum plantation (a plant related to Cacao producing edible fruit) with hand hoes. The female is 159 mm in length, the males range from 191 to 208 mm. They have more annuli than other known species (over 135 in all specimens) and a continuous tooth row (many species have a gap) with recurved but unserrated teeth.

Microcaecilia butantan,specimen in life dorsal view. Bar is 5 mm. Wilkinson et al. (2015).

Little is known of the natural history of this species, but it was easily found in the rainy season, within both the plantation where it was discovered and the surrounding forest, suggesting that it has a fairly high population at least locally, and so it is not at the current time considered to be under any immediate conservation threat.

The habitat where Microcaecilia butantan was found living. Wilkinson et al. (2015).

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A new species of Caecilian from French Guiana.                                                                            Caecilians (Gymnophiona) are a group of Amphibians only distantly related to Frogs and Salamanders. They have lost all limbs, and live a burrowing lifestyle in moist tropical forests. Caecilians have banded...

New Amphibians from Northeast India.

Caecilians are limbless burrowing Amphibians found in tropical regions of Asia, Africa and South America. They resemble Earthworms, with circular folds on their skin which make them look...

 

 

 

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The enigmatic Pleistocene Amphibians of Okinawa Island.

In the late 1960s and early 1970s a series of anthropological excavations were carried out at Minatogawa Fissure on southern Okinawa Island, producing a number of Late Pleistocene Human bones, as well as associated bones of other terrestrial vertebrates. Whilst most of the bones were from animals still found on Okinawa, or neighbouring members of the central Ryukyu Islands, or at least extinct animals thought to have been endemic (native) to the islands, a number of Frog species were reported which are today absent from the Ryukyus, but found in other parts of Japan. This is puzzling, as the Ryukyu Islands are generally thought to be biogeographically distinct from the rest of Japan; eleven out of fourteen Amphibian species found in the Central Ryukyus today are found nowhere else, two species are also found in southern China, with only a single species, the wide ranging Marsh Frog, Fejervarya kawamurai, is shared with the rest of Japan, and this species is also found in southern China and is thought likely to have reached the Central Ryukus in a separate dispersal event from the mainland. A specimen of Polypedates leucomystax, a Southeast Asian Frog otherwise thought to have been introduced to the islands in the mid twentieth century was also reported.

In addition these excavations yielded a number of Frog species still found in the on the island, but restricted to the moister, more forested northern part of the island. This is problematic, as the Pleistocene climate of Okinawa is interpreted to have been cooler and drier, which would cause such frogs to have had a more limited range, rather than an expanded one, and also because pollen associated with the tree species now found in the woodland on the north of the island has not been found here, implying that the south of the island was as lacking in woodland in the Pleistocene as it is today. Furthermore, the fissure is in an area of limestone karst (soft, absorbent and highly porous limestone), which would make it hard for bodies of standing water to form here under any circumstances.

In a paper published in the journal Palaeontologica Electronica in January 2015, Yasuyuki Nakamura of the Tropical Biosphere Research Center at the University of the Ryukyus and Hidetoshi Ota of the Institute of Natural and Environmental Sciences at the University of Hyogo and the Museum of Nature and Human Activities in Hyogo, Frog and Newt bones recovered from a more recent study at Minatogawa Fissure, as well as new excavations at the nearby Sashiki Fissure.

Maps of the Ryukyu Archipelago (1, 2) and Okinawajima Island (3). The map of Okinawajima shows topography, distribution of the Pleistocene limestone, and study sites.Nakamura & Ota (2015).

The sediments in the Minatogawa Fissure have been dated to about 15 670 years ago, towards the end of the Last Glacial Maximum. It is located in the Minatogawa Formation above the Yuhi River on the southeastern part of the island. Nakamura and Ota were unable to access the material from the original 1960s and 1970s excavations, nor any details of how the material was analysed (the previous publications covering the material simply listed the species). They were, however, able to access a series of Amphibian bones obtained by water-screening sediments from the site during a more recent excavation at the fissure in 1998-2001. These were compared to specimens of Amphibians from the Ryukus, other areas of Japan, and adjacent areas such as the Korean Peninsula.

The 1998-2001 Minatogawa Fissure material yielded a single humerus assigned to a female Namiye’s Frog, Limnonectesnamiyei, a species today found on northern, but not southern Okinawa and two humeri and two ilia attributed to female Holst’s Frogs, Babinaholsti, another species found today on the northern part of the island (leg bones are the most robust in Frogs, and therefore the most commonly preserved; it is usually possible to tell the sex of a From from its humeri).

Left female humerusfrom Minatogawa Fissure, referred to Limnonectes namiyei, lacking the proximal and distal parts and the crista ventralis in ventral (1), medial (2) and dorsal (3) views. Abbreviations: cr.par, crista paraventralis; fo.div, fossula dividens; ol.sc, olecranon scar; stm, spina tuberculi medialis. Scale bar is 5 mm. Nakamura & Ota (2015).

Much more abundant were bones of the Okinawa Tip-nosed Frog, Odorrana narina, with 21 right and 24 left female humeri, 16 right and 16 left male humeri and 22 right and 31 left ilia found in the material. This species is also found on the northern part of Okinawa today.Another abundant species was the Ryukyu Brown Frog, Rana ulma, with 41 right and 48 left female humeri, one left male humerus and eight right and nine left ilia found in the sample. This species is also found on northern Okinawa today.

Also present was a right humerus attributed to a female Ryukyu Kajika Frog, Buergeria japonica, a species still found on the southern part of Okinawa, and a pair of humeri of undetermined sex assigned to the Okinawa Green Tree Frog, Rhacophorus viridis viridis, also found on the southern part of Okinawa today.

Right femalehumerus from Minatogawa Fissure, referred to Buergeria japonica, lacking the proximal part in ventral (1), medial (2), and dorsal (3) views. Abbreviations: cr.lat, crista lateralis; cr.med, crista medialis; e.cap, eminentia capitata; ep.ul, epicondylus ulnaris; ol.sc, olecranon scar. Scale bar is 1 mm. Nakamura & Ota (2015).

Two species of Newt were also recovered from the material. Eight atlantes (the first vertebra after the skull), at least postatlantal precaudal vertebrae, 20 right and 15 left humeri and 11 right and 12 left femora were assigned to the Sword-tailed Newt, and three postatlantal precaudal vertebrae and one right femur were attributed to Anderson’s Crocodile Newt, Echinotriton andersoni, both of with are still present on southern Okinawa.

The Sashiki Fissure lies 6 km to the northeast of the Minatogowa Fissure in an uplifted terrace of the Naha Formation on the Chinen Peninsula. The fissure is a sinkhole that was exposed by limestone miners, then excavated by archaeologists from 2004 till 2008. The fissure yielded two separate deposits, a lower bed dated to between 28 729 and 31 745 years ago, around the beginning of the last glacial maximum, and an upper bed dated to between 3904 and 5558 years ago, during the Middle Holocene; these beds resting in separate depressions and not overlying one-another, though there is a thin layer at the top of the older deposits dated to about 7445 years ago (which did not yield any vertebrate fossils).

Photograph of the Sashiki Fissure (left) and schematic figure showing the structure of the fissure (right). In the right figure, broken lines represent the outline of the fissure behind rock, shaded areas represent studied sediments, and open circles represent the locations of the dating samples. Nakamura & Ota (2015).

The lower deposits at Sashiki yielded a single left ilium referred to Namiye’s Frog, Limnonectes namiyei, one right and five left female humeri, oneright and one left male humeri and six right and three leftilia assigned to Holst’s Frog, Babina holsti, and five right and five left female humeri, two right and one left male humeri and four right and one left ilia assigned to Ishikawa’s Frog, Odorrana ishikawae, all species found on the north of the island today.

Right female humerus in ventral (5), medial (6) and dorsal (7) views; (8–10) right male humerus lacking the proximal part in ventral (8), medial (9), and dorsal (10) views; and (11), right ilium lacking the anterior part in lateral view. Abbreviations: acet, acetabulum; acet.m, acetabular margin; cr.dors, crista dorsalis; cr.lat, crista lateralis; cr.med, crista medialis; cr.par, crista paraventralis; cr.ven, crista ventralis; e.cap, eminentia capitata; ep.rad, epicondylus radialis; ep.ul, epicondylus ulnaris; fo.div, fossula dividens; il.sh,ilial shaft; p.asc, pars ascendens; stm, spina tuberculi medialis; supr.fo, supracetabular fossa; tub.sup, tuber superior. Scale bars equal 5 mm. Nakamura & Ota (2015).

The Okinawa Tip-nosed Frog, Odorrananarina, which was one of the most abundant Frogs in the Minatogowa Fissure, but which is only found on the north of the island today, is represented in the lower Sashiki deposits by only four right and four left female humeri, oneright male humerus, one pelvic girdle and one left ilium.

Pelvic girdle: fused right and left ilia (lacking anterior parts) with the ischium and the pubis, in right lateral view. Abbreviations: acet, acetabulum; acet.m, acetabular margin; cr.dors, crista dorsalis; il.sh, ilial shaft; p.asc, pars ascendens; supr.fo, supracetabular fossa; tub.sup, tuber superior. Scale bars equal 5 mm. Nakamura & Ota (2015).

The other abundant Frog in the Minatogowa Fissure, the Ryukyu Brown Frog, Rana ulma, which is also absent from the south of the island today, is even more abundant in the lower Sashiki deposits, with 108 right and 68 left female humeri, 44 right and 43 left male humeri and 46 right and 47 left ilia assigned to this species.

Fossils referred to Rana ulma. (1–3), right female humerus in ventral (1) medial (2) and dorsal (3) views; (4–6)right male humerus in ventral (4) medial (5) and dorsal (6) views; (7) right iliumin lateral view. Abbreviations: acet, acetabulum; acet.m, acetabular margin; cr.dors, crista dorsalis; cr.lat, crista lateralis; cr.med, crista medialis; cr.par, crista paraventralis; cr.ven, cristaventralis; e.cap, eminentia capitata; ep.ul, epicondylus ulnaris; fo.div, fossula dividens; il.sh, ilial shaft; ol.sc, olecranon scar; p.asc, pars ascendens; stm, spina tuberculi medialis; supr.fo, supracetabular fossa; tub.sup, tuber superior. Arrows indicate the proximal ends of the crista paraventralis. Scale bars equal 1mm. Nakamura & Ota (2015).

The Okinawa Green Tree Frog, Rhacophorus viridis viridis, which was present in the Minatogowa Fissure and which is still found on south Okinawa today, is represented in the lower Sashiki Fissure by two right and five left female humeri, one left humeri of indeterminate sex, one right ilium and one pelvic girdle.

Pelvic girdle of Rhacophorus viridis viridis (fused right and left ilia lacking anterior parts withthe ischium) in left lateral view. Abbreviations: acet, acetabulum; acet.m, acetabular margin; cr.dors, crista dorsalis; il.sh, ilial shaft; p.asc, pars ascendens; pre.acet, preace tabular zone; supr.fo, supracetabular fossa; tub.sup, tuber superior. Scale bars equal 1mm. Nakamura & Ota (2015).

The Sword-tailed Newt, Cynops ensicauda, is represented in the lower Sashiki Fissure by two right and one leftmaxillae, one parietal-prootic-exoccipital, one left frontal, two right squamosals, six right and three left dentaries, five atlantes, 108 postatlantal precaudal vertebrae, 14 right and 11 left ribs, 41 right and 44 left humeri and 51 right and 41 left femora.

Fossils referred to Cynops ensicauda. (1–4) Postatlantal precaudal vertebra in anterior (1) left lateral (2) dorsal (3) and ventral (4) views; (5 and 6) atlas in anterior (5) and left lateral (6) views; (7) parietal-prootic-exoccipital in dorsal view; (8) right maxilla in lateral view; (9) right dentary in medial view; (10) right rib in posterior view; (11) right humerus in lateral view; and (12) right femur in posterior view. Abbreviations: con, condyle; diap, diapophyses; epi.pr, epipleural processes; neu.sp, neural spine; n.prep, notch for prearticular; parap, parapophyses; pos.pr, posterior process; subd.d, subdental ditch; zygap, zygapophyses. The arrow in 12 indicates a concavity. Scale bars equal 1 mm. Nakamura & Ota (2015).

Anderson’s Crocodile Newt, Echinotriton andersoni, is represented in the lower Sashiki Fissure unit by 11 right and 19 leftmaxillae, seven right and six left frontals, one parietal-prootic-exoccipital, nine right and nine left squamosals, three right and two left quadrates, 28 right and 42 left dentaries, 11 atlantes, 290 postatlantal precaudal vertebrae, 89 right and 92 left ribs, 68 right and 76 left humeri and (71 right and 92 left femora.

In the upper Sashiki Fissure unit, which is Middle Holocene in age, none of the species currently confined to northern Okinawa is present.

One species found in southern Okinawa today, and absent from the Pleistocene deposits is the Okinawa Narrow-mouthed Toad, Microhylao kinavensis, which is represented in the upper Sashiki Fissure deposits by two right ilia.

Right ilium of Microhylao kinavensisin lateral view, tub.sup, tuber superior. Scale bar equals 1mm. Nakamura & Ota (2015).

Also present in the upper unit at the Sashiki Fissure are one left ilium of the Ryukyu Kajika Frog, Buergeria japonica, one male left humerus of the Okinawa Green Tree Frog, Rhacophorus viridis viridis, and one right maxilla of the Sword-tailed Newt, Cynops ensicauda.

This study presents a very different view of the Pleistocene Amphibian fauna of southern Okinawa, with no species not found on the island today found in either the Late Pleistocene or Middle Holocene deposits, and the introduced Polypedates leucomystax absent from even the Holocene deposits. This leads Nakamura and Ota to conclude that the previous identifications of a range of exotic Frogs in Late Pleistocene deposits from the Minatogawa Fissure as erroneous.

The situation with Frogs found today on the north of the island is more complex, with Nakamura and Ota able to confirm the presence and even abundance of several north Okinawan species in Late Pleistocene deposits from the south of the island. This is highly problematic, as all previous evidence has suggested that the Late Pleistocene climate of the island was drier than today, with the south of the island less able to support such moisture loving species. Neither should pools of standing water, necessary for the survival of many of these species, form on the karst terrain that produced the fossils in anything short of a major flood event.

Maps showing current distributions (shaded areas) of five forest Frogs (Limnonectes namiyeia, Babina holstia, Odorrana ishikawaea, Odorrana narinaa, and Rana ulmaa, and the Newt Echinotriton andersonia on Okinawajima Island and adjacent islets. ‘?’ Denotes a population lacking a record or observation in the past 30 years. Nakamura & Ota (2015).

Nakamura and Ota observe that while the limestone areas of southern Okinawa are more-or-less free from streams or bodies of standing water, due to the drainage provided by the highly porous limestone, they are home to several natural springs, fed by waters flowing along the top of the water impermeable Shimajiri Group, which underlies the limestone units in places where these units are relatively thin or the limestone becomes slightly more dense (where water flowing through a rock body encounters a less porous area it must go somewhere, and tends to rise to the surface). They therefore suggest that in the Late Pleistocene the Minatogawa and Sashiki Fissures might have been home to such springs, providing standing bodies of water, which could have supported the moisture-loving Amphibians found preserved in the deposits there.

None of these species are present in the Middle Holocene deposits, suggesting that any such springs did not last beyond the last Pleistocene glaciation, and that the Amphibians of Okinawa Island had reached roughly their modern distributions by this time.

See also…

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