South America

The first cave-bound mollusc species from the Americas

Against the odds, a study by Brazilian researchers describes a new to science species of evidently cave-bound – or troglobitic – clam from northern Brazil.

Exclusively subterranean bivalves – the group of molluscs comprising clams, oysters, mussels, scallops – are considered a rarity. Prior to the present study, there had only been three such species confirmed in the world: all belonging to a small-sized mussel genus known from southeastern Europe. Furthermore, bivalves are not your typical ‘underworld’ dweller, since they are almost immobile and do not tolerate environments low in oxygen.

Against the odds, a recent study by Dr. Luiz Ricardo L. Simone (Museum of Zoology of the University of São Paulo) and Dr Rodrigo Lopes Ferreira (Federal University of Lavras), published in the open-access scholarly journal Subterranean Biology, describes a new to science species of evidently cave-bound – or troglobitic – clam from northern Brazil.

Small individuals of the newly described clam species Eupera troglobia sp. n. exposed to the air, next to a harvestman (Eusarcus sp.). Photo by Rodrigo Lopes Ferreira.

Named Eupera troglobia, the mollusk demonstrates features characteristic for organisms not meant to see the daylight, including lack of pigmentation, reduced size, delicate shell and fewer, yet larger eggs.

Curiously, it was back in 2006 when a report presenting a faunal survey of a cave in northern Brazil featured photographs of what was to be described as Eupera troglobia. However, the evidence was quickly dismissed: the clam must have been carried into the cave by water.

A submerged specimen of the newly described cave-bound clam species Eupera troglobia sp. n.

In 2010, Dr Rodrigo Lopes Ferreira accessed the report and noticed the depigmentation of the clams. Wondering whether it was indeed possible that he was looking at a troglobite, he searched amongst the collected specimens from that study, but could not find any of the discoloured bivalve.

Ten years later, his team visited the cave to specifically search for depigmented shells. Although the cave was partially flooded, the researchers were able to spot the specimens they needed attached to the walls of the cave.

In conclusion, the scientists highlight that their discovery is the latest reminder about how important the conservation of the fragile subterranean habitats is, given the treasure troves in their holdings.

Meanwhile, recently amended laws in Brazil put caves at considerably higher risk.

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Research paper:

Simone LRL, Ferreira RL (2022) Eupera troglobia sp. nov.: the first troglobitic bivalve from the Americas (Mollusca, Bivalvia, Sphaeriidae). Subterranean Biology 42: 165-184. https://doi.org/10.3897/subtbiol.42.78074

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Rare South American ground beetles sport unusual, likely multi-purpose antennal cleaners

The newly described Ball’s stange-combed beetle (*Nototylus balli*)
Photo by Terry L. Erwin

For 157 years, scientists have wished they could understand the evolutionary relationships of a curious South American ground beetle that was missing a distinctive feature of the huge family of ground beetles (Carabidae). Could it be that this rare species was indeed lacking a characteristic trait known in over 40,000 species worldwide and how could that be? Was that species assigned to the wrong family from the very beginning?

The species, Nototylus fryi, or Fry’s strange-combed beetle, is known so far only from a single, damaged specimen found in 1863 in the Brazilian State of Espíritu Santo, which today is kept in the Natural History Museum of London. So rare and unusual, due to its lack of “antennal cleaners” – specialised “combing” structures located on the forelegs and used by carabids to keep their antennae clean, it also prompted the description of its own genus: Nototylus, now colloquially called strange-combed beetles.

Left foreleg showing antennal grooming organs in the newly described Ball’s stange-combed beetle (*Nototylus balli*)
Photo by Terry L. Erwin

No mention of the structure was made in the original description of the species, so, at one point, scientists even started to wonder whether the beetle they were looking at was in fact a carabid at all.

Because the area where Fry’s strange-combed beetle had been found was once Southern Atlantic Forest, but today is mostly sugar cane fields, cacao plantations, and cattle ranches, scientists have feared that additional specimens of strange-combed beetles might never be collected again and that the group was already extinct. Recently, however, a US team of entomologists have reported the discovery of a second specimen, one also representing a second species of strange-combed beetles new to science.

Following a careful study of this second, poorly preserved specimen, collected in French Guiana in 2014, the team of Dr Terry Erwin (Smithsonian Institution), Dr David Kavanaugh (California Academy of Sciences) and Dr David Maddison (Oregon State University) described the species, Nototylus balli, or Ball’s strange-combed beetle, in a paper that they published in the open-access scholarly journal ZooKeys. The entomologists named the species in honour of their academic leader and renowned carabidologist George E. Ball, after presenting it to him in September 2016 around the time of his 90th birthday.

Despite its poor, yet relatively better condition, the new specimen shows that probable antennal grooming organs are indeed present in strange-combed beetles. However, they looked nothing like those seen in other genera of ground beetles and they are located on a different part of the front legs. Rather than stout and barely movable, the setae (hair-like structures) in the grooming organs of strange-combed beetles are slender, flexible and very differently shaped, which led the researchers to suggest that the structure had a different role in strange-combed beetles.

Judging from the shapes of the setae in the grooming organs, the scientists point out that they are best suited for painting or coating the antennae, rather than scraping or cleaning them. Their hypothesis is that these rare carabids use these grooming structures to cohabitate with ants or termites, where they use them to apply specific substances to their antennae, so that the host colony recognises them as a friendly species, a kind of behaviour already known in some beetles.

However, the mystery around the strange-combed beetle remains, as the scientists found no evidence of special secretory structures in the specimen studied. It turns out that the only way to test their hypothesis, as well as to better understand the evolutionary relationships of these beetles with other carabids is finding and observing additional, preferably live, specimens in their natural habitat. Fortunately, this new discovery shows that the continued search for these beetles may yield good results because strange-combed beetles are not extinct.

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Original source:

Erwin TL, Kavanaugh DH, Maddison DR (2020) After 157 years, a second specimen and species of the phylogenetically enigmatic and previously monobasic genus Nototylus Gemminger & Harold, 1868 (Coleoptera, Carabidae, Nototylini). ZooKeys 927: 65-74. https://doi.org/10.3897/zookeys.927.49584

How did coyotes conquer North America?

Coyotes now live across North America, from Alaska to Panama, California to Maine. But where they came from, and when, has been debated for decades.

Using museum specimens and fossil records, researchers from the North Carolina Museum of Natural Sciences and North Carolina State University have produced a comprehensive (and unprecedented) range history of the expanding species that can help reveal the ecology of predation as well as evolution through hybridization. Their findings are published in the open access journal ZooKeys.

The geographic distribution of coyotes has dramatically expanded since 1900, spreading across much of North America in a period when most other mammal species have been declining. Although this unprecedented expansion has been well-documented at the state/provincial scale, continent-wide picture of coyote spread been coarse and largely anecdotal. A more thorough compilation of available records was needed.

“We began by mapping the original range of coyotes using archaeological and fossil records,” says co-author Dr. Roland Kays, Head of the Museum’s Biodiversity Lab and Research Associate Professor in NC State’s Department of Forestry and Environmental Resources. “We then plotted their range expansion across North America from 1900 to 2016 using museum specimens, peer-reviewed reports, and game department records.”

In all, Kays and lead author James Hody, a graduate student at NC State University, reviewed more than 12,500 records covering the past 10,000 years for this study.

Their findings indicate that coyotes historically occupied a larger area of North America than generally suggested in the literature. Previous maps, as it turns out, had ancient coyotes only located across the central deserts and grasslands. However, fossils from across the arid west link the distribution of coyotes from 10,000 years ago to specimens collected in the late 1800s, proving that their geographic range was not only broader but had been established for hundreds, perhaps thousands of years, which also contradicts some widely-cited descriptions of their historical distribution.

It wasn’t until approximately 1920 that coyotes began their expansion across North America. This was likely aided by an expansion of human agriculture, forest fragmentation, and hybridization with other species. Eastern expansion, in particular, was aided by hybridization with wolves and dogs, resulting in size and color variation among eastern coyotes.

Before too long, coyotes may no longer be just a North American species. Kays notes that coyotes are continually expanding their range in Central America, having crossed the Panama Canal in 2010. Active camera traps are now spotting coyotes approaching the Darien Gap, a heavily forested region separating North and South America, suggesting that they are at the doorstep of South America.

“The expansion of coyotes across the American continent offers an incredible experiment for assessing ecological questions about their roles as predators, and evolutionary questions related to their hybridization with dogs and wolves,” adds Hody.

“By collecting and mapping these museum data we were able to correct old misconceptions of their original range, and more precisely map and date their recent expansions.”

“We hope these maps will provide useful context for future research into the ecology and evolution of this incredibly adaptive carnivore,” he concludes.

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(Originally published on Eurekalert! by North Carolina Museum of Natural Sciences.)

Original source:

Hody JW, Kays R (2018) Mapping the expansion of coyotes (Canis latrans) across North and Central America. ZooKeys 759: 81–97. https://doi.org/10.3897/zookeys.759.15149

New immigrant: Shiny Cowbirds noted from a recording altitude of 2,800 m in Ecuador

Two juveniles of Shiny Cowbird, a parasitic bird that lays its eggs in the nests of other birds, were spotted in the Andean city of Quito, Ecuador, for the first time. This finding represents an altitudinal expansion of approximately 500 m.

Breeding populations might have been prompted by forest fragmentation and/or climate change, suggest the research team, led by Dr Verónica Crespo-Pérez, professor at Pontificia Universidad Católica del Ecuador (PUCE). Resultingly, the ‘immigrants’ could be threatening native birds. The study is published in the open access Biodiversity Data Journal.

“The Shiny Cowbird is native to the lowlands of South America but within the last 100 years, it has been expanding its distribution to higher altitudes and latitudes” says the lead author.

The bird had already been noted from high altitudes in Bolivia and Perú, and in some localities in the Ecuadorian Andes. Since 2000, Juan Manuel Carrión, co-author and director of the Zoo in Quito, recalls observing Shiny cowbirds near his home in a valley near Quito at 2,300 m above sea level (asl). However, one has never before been reported from an altitude as high as 2,800 m asl.

Moreover, the fact that the observed individuals were juveniles means that the species is already breeding in the city.

“Such a significant expansion of reproductive birds, of approximately 500 m, could be related to human disturbances, like forest fragmentation or climate change,” adds Crespo-Pérez.

The observations took place at the PUCE campus about a year ago. Two juvenile Shiny cowbirds were seen parasitizing two different pairs of Rufous-collared Sparrow, one of the most common birds in Quito. The cowbirds displayed food-begging behaviors to adult sparrows, including chasing the sparrows on the ground and chanting intensely on bushes and tree branches.

“These observations mean that the birth mother of the cowbird laid her eggs in the nests of the sparrows, who inadvertently, became the cowbird’s foster parents and incubated, fed and cared for the it as if it were its own, even though the cowbird is almost twice as big,” says Miguel Pinto, co-author and professor at Escuela Politécnica Nacional, and former postdoctoral fellow at the Smithsonian Institution.

“The sparrows were not feeding fledglings of their own species, which suggests that the Cowbird could be having some negative effect on the Sparrow, at least on their ability to reproduce,” points out Tjitte de Vries, co-author and professor at PUCE.

There are several published reports of negative effects of Cowbirds on other birds, especially on species that are already endangered or have restricted distribution ranges. Therefore, this report of an expansion of the Shiny Cowbird towards higher altitudes may be of concern, mainly for native, endemic or endangered bird species.

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Original source:

Crespo-Pérez V, Pinto C, Carrión J, Jarrín E R, Poveda C, de Vries T (2016) The Shiny Cowbird, Molothrus bonariensis (Gmelin, 1789) (Aves: Icteridae), at 2,800 m asl in Quito, Ecuador.Biodiversity Data Journal 4: e8184. doi: 10.3897/BDJ.4.e8184

The owls beyond the Andes: Divergence between distant populations suggests new species

They might be looking quite identical, while perched above humanised farmlands and grasslands across several continents, but each of the populations of two owl species, living in the opposite hemispheres, might actually turn out to be yet another kind. This suggestion has been made by Dr. Nelson Colihueque and his team from Universidad de Los Lagos, Chile, based on new genetic divergence analyses of the Common Barn and the Short-eared Owl populations from southern Chile and comparing them with those from other geographic areas. The study is published in the open-access journal ZooKeys.

Although much has been known about the two widespread owl species, the knowledge about them has so far been restricted mainly to aspects such as their diet, conservation status and habitats. On the other hand, their genetic divergence in comparison with populations in distant areas has received little attention. Moreover, their taxonomical status is still based on traditional identification rather than modern methods such as the herein utilised mitochondrial COI sequencing.

Thus, the Chilean research team concluded a significant genetic divergence among the populations of both species from a few distinctive groups. In the case of the Common Barn Owl they compared the new analysis of its South American representatives with already available such data about populations from North America, Northern Europe and Australasia. For the Short-eared Owl, they compared Chilean and Argentinean birds with North American and North Asian.

One of the reasons behind such an evolutionary divergence might be the geographic isolation, experienced by the peripheral South American populations of both owl species. It is a consequence of the Andean Mountains acting as a natural barrier.

“In the case of the Common Barn Owl, the existence of geographic barriers to gene flow among populations on different continents is to be expected, and this in combination with its non-migratory or short-distance migratory behaviour, should contribute to promote the genetic divergence,” further explain the authors.

In conclusion, the researchers call for additional studies to clarify the taxonomic identification of these owl populations.

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Original source:

Colihueque N, Gantz A, Rau JR, Parraguez M (2015) Genetic divergence analysis of the Common Barn Owl Tyto alba (Scopoli, 1769) and the Short-eared Owl Asio flammeus (Pontoppidan, 1763) from southern Chile using COI sequence. ZooKeys 534: 135-146. doi: 10.3897/zookeys.534.5953