Critically Endangered

Genetic study reveals that a captive-bred population could save endangered crocodile from extinction

Since this species is almost extinct in the wild, the news brings hope for the recovery of populations.

The Orinoco crocodile (Crocodylus intermedius) is a critically endangered species native to the Orinoco River basin in Colombia and Venezuela. It is one of the largest crocodilian species in the world, reaching lengths of up to seven meters. Despite its impressive size, it is also the most endangered and least-studied of the New World crocodilians.

Female Orinoco crocodile from the Roberto Franco Tropical Biological Station´s ex-situ population.

The species has faced a severe population decline due to commercial overexploitation of its skin, which was highly sought after by the fashion industry of Europe, the USA and Japan in the 20^th century. As a result, the current estimated global population stands at less than 250 adult individuals.

Recognizing the critical status of the species, herpetologist Federico Medem established a captive breeding program for the Orinoco crocodile in 1971 at the Roberto Franco Tropical Biological Station (RFTBS) in Villavicencio. Currently, the RFTBS houses over 600 individuals, making it the largest stock of this species and the only one in Colombia. Remarkably, there might be more adult crocodiles kept there than in the wild.

Despite the success of the captive breeding program, reintroduction of animals into the wild has been challenging. This is primarily due to the lack of a comprehensive genetic characterization that can determine whether the population is genetically viable and has no signs of inbreeding, which can result in reduced fitness at the individual and population level. To ensure the successful reintroduction of the species, it was crucial to have a robust and conclusive genetic assessment that confirms the population’s genetic health and viability.

“We felt a sense of urgency to determine the genetic viability of the population in order to proceed with the reintroduction of animals and establish new populations of the species in Colombia. Therefore, we conducted a comprehensive genetic characterization using fast-evolving molecular markers on a sample of 551 crocodiles,” explains Ana María Saldarriaga, a former researcher at the Universidad Nacional de Colombia who is currently pursuing a Ph.D. at Fordham University.

“Our findings showed that the individuals within the population possess sufficient genetic diversity and are suitable for reintroduction efforts, as well as for maintaining and enhancing the genetic variability of the ex-situ population.”

“We demonstrated that molecular data could be used to improve the management of ex-situ conservation programs well beyond what could be achieved with pedigree information alone,” she and her colleagues write in a study just published in the journal Nature Conservation.

Based on the findings of this study, the Colombian government, along with other public and private conservation institutions and agencies, can use the individuals identified in this research to initiate the establishment of new populations in regions where the species has been completely depleted.

“Today, it is widely recognized that top predators, such as crocodiles, play fundamental roles in both aquatic and terrestrial ecosystems. They have a significant impact on the nutrient cycle, regulate fish populations, and contribute to important cross-ecosystem engineering processes,” stated Mario Vargas-Ramírez, professor at the Genetics Institute of the Universidad Nacional de Colombia and director of the RFTBS.

“Therefore, the reintroduction of the Orinoco crocodile to the Orinoco region is an urgent priority. Additionally, as the Orinoco crocodile is considered an umbrella species, its recovery and conservation efforts will have a positive cascading effect, protecting a large number of species that coexist in the same environment.”

Research article:

Saldarriaga-Gómez AM, Ardila-Robayo MC, Medem F, Vargas-Ramírez M (2023) Hope is the last thing lost: Colombian captive-bred population of the critically endangered Orinoco crocodile (Crocodylus intermedius) is a genetic reservoir that could help to save the species from extinction. Nature Conservation 53: 85-103. https://doi.org/10.3897/natureconservation.53.104000

Photos by Mario Vargas-Ramírez.

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A new Critically Endangered frog named after “the man from the floodplain full of frogs”

A new species of a Critically Endangered miniaturised stump-toed frog of the genus Stumpffia found in Madagascar is named Stumpffia froschaueri after “the man from the floodplain full of frogs”, Christoph Froschauer. The namesake of the new frog is famous for being the first, and European-wide renowned, printer from Zürich, famous for printing “Historia animalium” and the “Zürich Bible”. The finding is published in the peer-reviewed open-access journal Zookeys.

A new species proposed to be classified as Critically Endangered of miniaturised stump-toed frog of the genus Stumpffia, found in Madagascar, is named Stumpffia froschaueri after “the man from the floodplain full of frogs”, Christoph Froschauer. The namesake of the new frog is famous for being the first, and European wide renowned, printer from Zürich, famous for printing “Historia animalium” and the “Zürich Bible”.

Christoph Froschauer’s (ca. 1490 – April 1564) family name means “the man from the floodplain full of frogs”, and the printer used to sign his books with a woodcut, showing frogs under a tree in a landscape. Amongst his publications are works by Zwingli, Bullinger, Gessner, Erasmus von Rotterdam and Luther, and as a gift for his art, the printer was given citizenship in Zürich in 1519. Now, scientists have also honoured Froschauer’s great contributions by naming a new frog species after him.

The discovery, made by an international team of scientists from CIBIO (Research Centre in Biodiversity and Genetic Resources) of the University of Porto, Zoological Society of London, University of Lisbon, University of Brighton, University of Bristol, University of Antananarivo and Museo Regionale di Scienze Naturali, is published in the open-access peer-reviewed journal Zookeys.

The new species is reliably known only from a few specimens collected in three forest patches of the Sahamalaza region, an area severely threatened by fire, drought and high levels of forest clearance.

“In Anketsakely and Ankarafa this species has been found only in areas with relatively undisturbed forest, and active individuals were found during the day within the leaf-litter on the forest floor, where discreet calling males were also detected”,
shares lead author Dr. Angelica Crottini from CIBIO.

Even though two out of the three forest patches where Stumpffia froschaueri occurs are now part of a UNESCO Biosphere Reserve, there is a lack in forest border patrols and the area remains under strong pressure from slash-and-burn activities and timber harvesting. Habitat loss and fragmentation are likely to represent a huge threat to the species’ survival and cause population declines, unless remedial actions to enforce the protection of these habitats are taken. The scientists suggest to classify Stumpffia froschaueri as a Critically Endangered species according to criteria of the IUCN Red List.

Life colouration of Stumpffia froschaueri sp. nov., dorsolateral view of paratype ZSM 167/2019 (ACZCV 0968) from Ankarafa Forest
Credit: Gonçalo M. Rosa
License: CC-BY 4.0

“We here reiterate the need to continue with field survey activities, giving particular attention to small and marginal areas, where several microendemic candidate species are likely waiting to be discovered and formally described. This description confirms the Sahamalaza Peninsula as an important hotspot of amphibian diversity, with several threatened species relying almost entirely on the persistence of these residual forest fragments”,
concludes Dr. Crottini.

Life colouration of Stumpffia froschaueri sp. nov., dorsolateral view of paratype ZSM 166/2019 (ACZCV 0939) from Ankarafa Forest
Credit: Gonçalo M. Rosa
License: CC-BY 4.0

Contact:
Dr. Angelica Crottini
Email: tiliquait@yahoo.it

Original source:
Crottini A, Rosa GM, Penny SG, Cocca W, Holderied MW, Rakotozafy LMS, Andreone F (2020) A new stump-toed frog from the transitional forests of NW Madagascar (Anura, Microhylidae, Cophylinae, Stumpffia). ZooKeys 933: 139-164. https://doi.org/10.3897/zookeys.933.47619

Light at the end of the tunnel: Restored forest now shelters dozens of endangered species

During the last twenty years, scientists worked hard to protect and restore the scattered patches of a dilapidated forest and its surroundings of agricultural and fallow vegetation in southern Benin.

With the help of their locally recruited assistants, Peter Neuenschwander, International Institute of Tropical Agriculture, Benin, and Aristide Adomou, University of Abomey-Calavi, Benin, successfully thinned out the alien timber growing there and introduced 253 species, whose seeds and plantlets they had managed to collect from the last remnants of the original forest. Their research article is published in the open access journal Nature Conservation.

Today, the rehabilitated forest in Drabo harbours about 600 species of plants and constitutes a sanctuary for many animals, including the critically endangered and endemic red-bellied monkey.

Over the course of the last two decades, pantropical weedy species declined, while West-African forest species increased in numbers. Of the former, fifty-two species, mostly trees, shrubs and lianas, are listed as threatened – more than those in any other existing forest in Benin. Furthermore, some of the critically endangered species amongst them can be found exclusively in the last small, often sacred forests in Benin, which while covering merely 0.02% of the national territory, harbour 64% of all critically endangered plant species.

“The biodiversity richness of the rehabilitated forests of Drabo now rivals that of natural rainforest remnants of the region,” note the authors.

The newly restored forest in Drabo is relatively easy to access due to its proximity to large towns. It is intended to become an educational and research centre maintained by the International Institute of Tropical Agriculture. In fact, it already serves as an exemplary forest in the region.

With their initiative, the scientists and their followers demonstrate that by involving local communities and taking their customs into consideration, the safety of exposed precious ecosystems, even if located in a densely populated area, can be effectively assured.

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Original source:

Neuenschwander P, Adomou AC (2017) Reconstituting a rainforest patch in southern Benin for the protection of threatened plants. Nature Conservation 21: 57-82. https://doi.org/10.3897/natureconservation.21.13906

The Cerberus Groundsnake is a Critically Endangered new species from Ecuador

With as many as 140 species, Atractus is the most diverse snake genus in the world, even though it can be found exclusively in Central and South America. However, these colubrid ground snakes seem largely under-researched, since there have been thirty-three species discovered in the last ten years only.

As concluded by a team of scientists, led by Alejandro Arteaga, Tropical Herping, Ecuador, this is the result of a lack of DNA information in the original descriptions of many of these species. Consequently, there have been a lot of specimens sitting in museum collection that remain either misidentified, or anonymous.

To address the issue around the problematic identification of these snakes and their correct placement in the tree of life, the scientists have studied the hereditary molecular differences in the genus using both newly collected specimens, as well as previous publications on the species occurring in the Pacific lowlands and the adjacent Andean slopes.

Their research results in a new paper, published in the open access journal ZooKeys, which describes a total of three new species from Ecuador. The authors also propose a new species group and a redefinition of a previously established one.

Interestingly, one of the new species is to be referred to as Cerberus Groundsnake, while in the books it will appear under Atractus cerberus. It is predominantly brown in colour with faint black longitudinal bands, and measures about 21 – 31 cm in length. The biologists justify the curious name of this species with the peculiar location where they spotted the first known specimen. Found at the gates of the newly formed “Refinería del Pacífico”, a massive industrial oil-processing plant, the authors were quick to recall the multi-headed monstrous dog Cerberus, known to be guarding the gates of the underworld, according to Greek mythology.

In terms of their conservation status, the scientists have proposed the Cerberus Groundsnake to be listed as Critically Endangered, according to the IUCN criteria, since its single known habitat is highly likely to be the only one, being isolated from any other similar habitats. Moreover, it comprises a relatively small patch of land, which in turn is declining in both size and quality due to deforestation. According to the IUCN criteria, a Critically Endangered status is given to a (group of) species whenever the best available evidence indicates that it faces an extremely high risk of extinction in the wild.

The other two new species, the Indistinct (Atractus esepe) and the Pyron’s (Atractus pyroni) ground snakes are to be listed as Data Deficient as the information about them is currently insufficient for their risk of extinction to be assessed.

Having increased the number of Atractus species in Ecuador to twenty-seven, the authors expect that the count is yet to rise. “We hope that the novel genetic and morphological data provided herein will promote future researchers to examine species boundaries in Atractus, as additional work clearly is waiting,” they add.

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Original source:

Arteaga A, Mebert K, Valencia JH, Cisneros-Heredia DF, Peñafiel N, Reyes-Puig C, Vieira-Fernandes JL, Guayasamin JM (2017) Molecular phylogeny of Atractus (Serpentes, Dipsadidae), with emphasis on Ecuadorian species and the description of three new taxa. ZooKeys 661: 91-123. https://doi.org/10.3897/zookeys.661.11224

Exceptional reproductive biology in extremely restricted critically endangered Nimba toad

The critically endangered Nimba toad is long known for its exceptional reproductive biology. The females of this unique species give live birth to fully developed juveniles, having for nine months continuously provided nutrition to the foetuses in the womb (matrotrophy). While live birth (viviparity) among frogs and toads is rather an exception than a common characteristic, matrotrophy, in place of alternatives such as the foetus being fed with yolk, unfertilized eggs, or smaller siblings, is what makes the Nimba toad one of a kind.

However, more than 40 years of research had not been comprehensively, accessibly and completely summarised. The gap has recently been filled with a new paper, published in the open access journal Zoosystematics and Evolution by German scientists Drs. Laura Sandberger-Loua and Mark-Oliver Rödel, both affiliated with Museum für Naturkunde, Berlin, and Dr. Hendrik Müller, Friedrich-Schiller-Universität Jena.

Studying the phenomenon, the scientists went through the literature published over four decades to gather the scattered details. They have also discussed the relationship between the toad’s reproductive biology and its specific habitat of merely 4 km² of high altitude grasslands located at a minimum of 1,200 m in the Nimba mountains, West Africa.

The climate of the area is characterised by a rainy season lasting from April to October and a dry season from November to February/March. These seasons are found to determine the activity of the Nimba toads. The amphibians are only active during the rainy season, when they give birth to their young, mate, and then find shelter underground, where they stay dormant during the dry season.

Visibly females can be distinguished from male Nimba toads by their differing cloaca and often larger size, compared to the males. Also, males show darker backs and, during most of their adult life, nuptial pads on their thumbs, which look like spiky swellings. This secondary sex characteristic, in its seasonal change linked to spermatogenesis, is used by the males to grasp tightly the female while mating.

In this species mating occurs without a copulatory organ. Instead, the sperm is transferred through connection of the cloacae, where the male’s swells and encloses the female’s cloaca. Furthermore, Nimba toads have a unique behavioural repertoire. Males crouch on their front legs and as soon as the female moves, follow her and grab her tightly in the groin. Due to the spiky nuptial pads, the males often injure their partner.

Giving birth in Nimba toads may take over two days, depending on the number of offspring, which can be up to 12 in older females – far fewer than the hundreds of eggs in most toad species. While giving birth, a female assumes a unique “birthing posture” to compensate for the lack of enough muscle power to expel juveniles. By the time the juveniles are ready to be born, they have already taken up nearly all the space in their mother’s body. The scientists conclude that the offspring play an active role in the process, as a juvenile toad’s death midway in the oviduct leads to the mother dying of sepsis.

Living exclusively in the Nimba mountains, and being listed as Critically Endangered, according to the IUCN, the studied toad is only one of the species restricted to the high altitude grasslands, which led to the declaration of the Nimba mountains as a World Heritage Site by UNESCO. Separated from other mountains, its inhabitants are isolated from external contacts, thus presumably leading to their evolutionary separation from related species. Furthermore, the toad’s unique reproductive biology is probably the result of this isolation, argue the authors.

In conclusion, the authors suggest that “it is likely that the harsh unpredictable environment and scarcity of open water promoted viviparity in Nimba toads, or supported the survival of this unique reproductive mode in these special and isolated conditions. Considering their complex life cycle, in which reproductive and seasonal cycles are tightly linked, understanding and protecting the Nimba toad’s threatened environment is of utmost importance.”

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Original source:

Sandberger-Loua L, Müller H, Rödel M-O (2017) A review of the reproductive biology of the only known matrotrophic viviparous anuran, the West African Nimba toad, Nimbaphrynoides occidentalis. Zoosystematics and Evolution 93(1): 105-133. https://doi.org/10.3897/zse.93.10489

Species conservation profile of a critically endangered endemic for the Azores spider

Subject to continuing population decline due to a number of factors, an exclusively cave-dwelling (troglobitic) spider endemic to the Azores is considered as Critically Endangered according to the IUCN Red List criteria.

To provide a fast output, potentially benefiting the arachnid’s survival, scientists from the IUCN – Spider and Scorpion Specialist Group and the Azorean Biodiversity Group (cE3c) at University of Azores, where the main objective is to perform research that addresses societal challenges in ecology, evolution and the environment, also known as the three E’s from the centre’s name abbreviation, teamed up with colleagues from University of Barcelona, Spain, and the Finnish Museum of Natural History.

Together, they make use of a specialised novel publication type feature, called Species Conservation Profile, created by the open access journal Biodiversity Data Journal, to provide scholarly credit and citation for the IUCN Red List species page, as well as pinpoint the population trends and the reasons behind them.

The studied spider species (scientifically called Turinyphia cavernicola) is a pale creature with long legs, large eyes and a total size of merely 2 mm in length. These spiders never leave their underground habitats, which are strictly humid lava tubes and volcanic pits. There they build sheet webs in small holes and crevices on the walls of the caves.

Not only is the species restricted to a single island within the Azorean archipelago (Portugal), but it is only found in three caves. Furthermore, out of the three, only one of them is home to a sustainable large population. These caves are under severe threat due to pasture intensification, road construction and tourist activities.

Although there is not much information about the species distribution through the years, with the spider having been discovered as recently as in 2008, the authors make the assumption that originally there have been significantly greater populations. Not only have they studied thoroughly another fifteen caves located on the island without finding any individuals, but they have identified increasing anthropogenic impact on the habitat.

“The species original distribution was potentially very large compared with the current,” the scientists explain. “Relatively intensive searches in and around the current caves where the species occurs have failed to find additional subpopulations.”

“The trend of decline is based on the assumption that this species can occur in all these caves and that the absence is due to anthropogenic disturbance on caves during the last 50 years,” they note.

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Original source:

Borges P, Crespo L, Cardoso P (2016) Species conservation profile of the cave spiderTurinyphia cavernicola (Araneae, Linyphiidae) from Terceira Island, Azores, Portugal.Biodiversity Data Journal 4: e10274. doi: 10.3897/BDJ.4.e10274

Orchid or Demon: Flower of a new species of orchid looks like a devil’s head

A lone and unique population of about 30 reddish to dark violet-maroon orchids grows on the small patch of land between the borders of two Colombian departments. However, its extremely small habitat is far from the only striking thing about the new species.

A closer look at its flowers’ heart reveals what appears to be a devil’s head. Named after its demonic patterns, the new orchid species, Telipogon diabolicus, is described in the open access journal PhytoKeys.

Discovered by Dr Marta Kolanowska and Prof Dariusz Szlachetko, both affiliated with University of Gdansk, Poland, together with Dr Ramiro Medina Trejo, Colombia, the new orchid grows a stem measuring between 5.5 – 9 cm in height.

With its only known habitat restricted to a single population spread across a dwarf montane forest at the border between departments Putumayo and Nariño, southern Colombia, the devilish orchid is assigned as a Critically Endangered species in the IUCN Red List.

Although the curious orchid could be mistakenly taken for a few other species, there are still some easy to see physical traits that make the flower stand out. Apart from the demon’s head hidden at the heart of its colours, the petals themselves are characteristically clawed. This feature has not been found in any other Colombian species of the genus.

“In the most recent catalogue of Colombian plants almost 3600 orchid species representing nearly 250 genera are included,” remind the authors. “However, there is no doubt that hundreds of species occurring in this country remain undiscovered. Only in 2015 over 20 novelties were published based on material collected in Colombia.”

Original source:

Kolanowska M, Szlachetko DL, Trejo RM (2016) Telipogon diabolicus (Orchidaceae, Oncidiinae), a new species from southern Colombia. PhytoKeys 65: 113-124. doi:10.3897/phytokeys.65.8674