Species New to Science

   

ABSTRACT

Polar bears (Ursus maritimus) depend on sea ice, where they hunt ice-associated seals. However, they are opportunistic predators and scavengers with a long list of known prey species. Here we report from a small fjord in Svalbard, Norwegian High Arctic, a sighting of an adult male polar bear preying on two white-beaked dolphins (Lagenorhynchus albirostris) on 23 April 2014. This is the first record of this species as polar bear prey. White-beaked dolphins are frequent visitors to Svalbard waters in summer, but have not previously been reported this far north in early spring. We suggest they were trapped in the ice after strong northerly winds the days before, and possibly killed when forced to surface for air at a small opening in the ice. The bear had consumed most parts of one dolphin. When observed he was in the process of covering the mostly intact second dolphin with snow. Such caching behaviour is generally considered untypical of polar bears. During the following ice-free summer and autumn, at least seven different white-beaked dolphin carcasses were observed in or near the same area. We suggest, based on the area and the degree to which these dolphins had decayed, that they were likely from the same pod and also suffered death due to entrapment in the ice in April. At least six different polar bears were seen scavenging on the carcasses.

Keywords: White-beaked dolphin; polar bear; caching; Arctic; Svalbard.

Jon Aars, Magnus Andersen, Agnès Brenière and Samuel Blanc. 2015. White-beaked Dolphins trapped in the Ice and eaten by Polar Bears. Polar Research 2015, 34, 26612. DOI: 10.3402/polar.v34.26612

Abstract

Animals often mimic dangerous or toxic species to deter predators; however, mimicry of such species may not always be possible and mimicry of benign species seems unlikely to confer anti-predator benefits. We reveal a system in which a bird mimics the alarm calls of harmless species to fool a predator 40 times its size and protect its offspring against attack. Our experiments revealed that brown thornbills (Acanthiza pusilla) mimic a chorus of other species' aerial alarm calls, a cue of an Accipiter hawk in flight, when predators attack their nest. The absence of any flying predators in this context implies that these alarms convey deceptive information about the type of danger present. Experiments on the primary nest predators of thornbills, pied currawongs (Strepera graculina), revealed that the predators treat these alarms as if they themselves are threatened by flying hawks, either by scanning the sky for danger or fleeing, confirming a deceptive function. In turn, these distractions delay attack and provide thornbill nestlings with an opportunity to escape. This sophisticated defence strategy exploits the complex web of interactions among multiple species across several trophic levels, and in particular exploits a predator's ability to eavesdrop on and respond appropriately to heterospecific alarm calls. Our findings demonstrate that prey can fool predators by deceptively mimicking alarm calls of harmless species, suggesting that defensive mimicry could be more widespread because of indirect effects on predators within a web of eavesdropping.

Branislav Igic, Jessica McLachlan, Inkeri Lehtinen and Robert D. Magrath. 2015. Crying Wolf to A Predator: Deceptive Vocal Mimicry by A Bird Protecting Young. Proceedings of the Royal Society B. 282(1809). DOI: 10.1098/rspb.2015.0798.

Brown Thornbill Mimics Alarm Calls of Other Birds to Scare off Predators | Biology | Sci-News.com: http://www.sci-news.com/biology/science-brown-thornbill-mimics-birds-2870.html 

Abstract

Three new species of the streptaxid snail genus Perrottetia are described from north and northeastern Thailand, Perrottetia aquilonaria sp. n., Perrottetia dermapyrrhosa sp. n. and Perrottetia phuphamanensis sp. n. Each species is endemic to a single or a few limestone mountain ranges. The species are characterized by the morphology of their genital organs, as well as by shell characters. Perrottetia aquilonaria sp. n. has a club shaped distal penis and large penial hooks are present and penial papillae cover almost the entire penial hook portion; adjacent areas possess low reticulated folds. Perrottetia dermapyrrhosa sp. n. has a long genital atrium and the penial sheath is about two-thirds of the penis length. Penial hooks are long, scattered and sunken into deep ovate hollows; vaginal hooks are present. Perrottetia phuphamanensis sp. n. has a rounded and protruded shell periphery. The aperture is subcircular, peristome is thick and the second parietal lamella is adjacent to the first parietal lamella; a basal lamella is the smaller than in the other Thai species.

Keywords: Systematics, land snails, taxonomy, genitalia, predator

Thanit Siriboon, Chirasak Sutcharit, Fred Naggs, Somsak Panha. 2013. Three New Species of the Carnivorous Snail genus Perrottetia Kobelt, 1905 from Thailand (Pulmonata, Streptaxidae). ZooKeys. 287 (0): 41 DOI: 10.3897/zookeys.287.4572

http://www.sciencedaily.com/releases/2013/04/130415172415.htm

http://www.wildlifeextra.com/go/news/thailand-snail.html

Abstract

Invasive alien American bullfrog populations are commonly identified as a pernicious influence on the survival of native species due to their adaptability, proliferation and consequent ecological impacts through competition and predation. However, it has been difficult to determine conclusively their destructive influence due to the fragmentary and geographically dispersed nature of the historical database. An expanding meta-population of invasive American bullfrogs, Rana catesbeiana (= Lithobates catesbeianus), became established on southern Vancouver Island, British Columbia, Canada in the mid- to late 1980s. An on-going bullfrog control program begun in 2006 offered a unique opportunity to examine the stomach contents removed from 5, 075 adult and juvenile bullfrogs collected from 60 sites throughout the active season (April to October). Of 15 classes of organisms identified in the diet, insects were numerically dominant, particularly social wasps and odonates (damselflies and dragonflies). Seasonality and site-specific habitat characteristics influenced prey occurrence and abundance. Native vertebrates in the diet included fish, frogs, salamanders, snakes, lizards, turtles, birds, and mammals, including some of conservation concern. Certain predators of bullfrog tadpoles and juveniles are commonly preyed upon by adult bullfrogs, thereby suppressing their effectiveness as biological checks to bullfrog population growth. Prey species with anti-predator defences, such as wasps and sticklebacks, were sometimes eaten in abundance. Many prey species have some type of anti-predator defence, such as wasp stingers or stickleback spines, but there was no indication of conditioned avoidance to any of these. Results from this study reinforce the conclusion that, as an invasive alien, the American bullfrog is an opportunistic and seemingly unspecialized predator that has a uniquely large and complex ecological footprint both above and below the water surface.

Keywords: Bullfrog, Rana catesbeiana, Lithobates catesbeianus, predation, diet, invasive species

Conclusions

1. As an “invasive alien” the American bullfrog is a highly adaptable, opportunistic, and seemingly unspecialized predator that has a uniquely large and complex ecological footprint both above and below the water surface.

2. Insects were the dominate prey group found in 84% of prey instances and 93% of stomachs with food, but seasonality influenced the relative importance of any one insect group over another at any given time period.

3. Cannibalism was found to be a minor component of the diet in terms of relative instances and accounted for approximately 34% of all instances of predation on amphibians.

4. Bullfrog control measures should be routinely factored into management plans for rare and endangered species, such as the western painted turtle on southern Vancouver Island, which are particularly vulnerable to bullfrog predation.

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What do American bullfrogs eat when they're away from home? Practically everything! 

American bullfrogs are native to eastern North America but have been transported by people to many other parts of the globe, and other parts of North America, where they have readily established populations and become an invasive alien menace to native ecosystems. In the largest study of its kind to date, the stomach contents of over 5,000 invasive alien American bullfrogs from 60 lakes and ponds on southern Vancouver Island were examined to identify the native and exotic animals that they had preyed upon. The study was published in the open access journal NeoBiota.

Over 15 classes of animals were reported from a total of 18,814 identifiable prey remains, including terrestrial and aquatic insects, spiders, crayfish, fish, frogs, salamanders, newts, snakes, lizards, turtles, birds, and small mammals. The study examined the stomach contents of adults and juveniles of all size-classes, but excluded tadpoles. These results show that bullfrogs will attack and consume virtually any organism that is within reach and can be swallowed, including their own species.

Previous studies on bullfrog diet have examined relatively small numbers of stomachs from a comparatively small number of lakes and ponds. Our results reinforce the general consensus that there is good reason for concern about the ecological harm that uncontrolled populations of American bullfrogs might have, or are having, on populations of native species.

For decades, bullfrogs have been transported and released around the world by prospective frog-farmers, pet owners, game managers, recreational fishermen, biological supply houses; and even by entrants in frog jumping contests. They adapt readily to a variety of habitats from the tropics to temperate zones and once established, their numbers grow fast with each adult female producing about 20,000 or more eggs per year. For these reasons, American bullfrogs are internationally recognized as one of the 100 worst invasive alien species in the world.

Jancowski, K, Orchard, SA. 2013. Stomach contents from invasive American bullfrogs Rana catesbeiana (= Lithobates catesbeianus) on southern Vancouver Island, British Columbia, Canada. NeoBiota. 16: 17, doi: 10.3897/neobiota.16.3806

http://www.pensoft.net/news.php?n=214&SESID=9526eaee97768f1f8eeefbcdbde98d0

Tyrannoneustes lythrodectikos

Young, De Andrade, Brusatte, Sakamoto & Liston 2013

Abstract

The Oxford Clay Formation of England has yielded numerous sympatric species of metriorhynchid crocodylomorphs, although disagreement has persisted regarding the number of valid species. For over 140 years teeth reminiscent of the genus Dakosaurus have been known from the Oxford Clay Formation but these have never been properly described and their taxonomy and systematic affinity remain contentious. Furthermore, an enigmatic mandible and associated postcranial skeleton discovered by Alfred Leeds in the Fletton brick pits near Peterborough also remains undescribed. We show that this specimen, and several isolated teeth, represents the oldest known remains of a large-bodied predatory metriorhynchid. This material is described herein and referred to Tyrannoneustes lythrodectikos gen. et sp. nov. This species has a unique occlusal pattern: the dentition was arranged so that the posterior maxillodentary teeth interlock in the same plane and occlude mesiodistally. It is the first described crocodylomorph with microscopic denticles that are not contiguous along the carinae (forming short series of up to 10 denticles) and do not noticeably alter the height of the keel. Additionally, the dorsally expanded and curved posterior region of the mandible ventrally displaced the dentary tooth row relative to the jaw joint facilitating the enlargement of the dentition and increasing optimum gape. Therefore, Tyrannoneustes would have been a large-bodied marine predator that was well-suited to feed on larger prey than other contemporaneous metriorhynchids. A new phylogenetic analysis finds Tyrannoneustes to be the sister taxon to the subclade Geosaurini. An isolated tooth, humerus, and well-preserved mandible suggest a second species of metriorhynchid super-predator may also have lived in the Oxford Clay sea. Finally, we revise the diagnoses and descriptions of the other Oxford Clay metriorhynchid species, providing a guide for differentiating the many contemporaneous taxa from this exceptional fossil assemblage.

Keywords: denticle, Geosaurini, hypercarnivore, Metriorhynchidae, Tyrannoneustes

Tyrannoneustes gen. nov.

Type species. Tyrannoneustes lythrodectikos sp. nov.

Etymology. Meaning ‘tyrant swimmer’: Tyrannos is Ancient Greek for an illegitimate ruler, while –neustes is Ancient Greek for swimmer.

Geological range. Middle Callovian to Early Oxfordian (possibly Late Oxfordian). Geographical range. European endemic (England). Isolated Callovian-Oxfordian teeth from France and Poland are referred to this genus (see below).

Tyrannoneustes lythrodectikos sp. nov.

Etymology. ‘Blood-biting tyrant swimmer’. Lythros meaning blood, and dectikos meaning biting, both from Ancient Greek; named for its super-predatory nature.

Type locality and horizon. Fletton, Cambridgeshire, England. Peterborough Member, Oxford Clay Formation. Jasoni Sub-Boreal ammonite-zone, Middle Callovian, Middle Jurassic (Cox et al. 1992).

Fossil remains in museum found to be 165 million year old marine super-predator 

—Researchers examining a fossil specimen discovered in a museum storage bin have found it to be the remains of a super-predator that lived during the Jurassic Period, around 165 million years ago. They describe the specimen, named Tyrannoneustes lythrodectikos, as looking like a cross between a modern dolphin and a shark or crocodile.

: http://phys.org/news/2013-01-fossil-museum-million-year-marine.html

Tyrannoneustes lythrodectikos, meaning "tyrant swimmer that bites" in Latin, was found in 1919 in a clay pit near the British town of Peterborough (the Oxford Clay Formation) by an amateur bone collector. Since that time it has resided, hidden away in Glasgow's Hunterian museum. The skeletal remains include a jawbone with serrated teeth that the researchers, from the University of Edinburgh describe as an indication that the creature was a super-predator one that preys on animals that are as big as it is, or even bigger. 

The research team, led by Mark Young, says the time period during which the tyrant swimmer lived would have had it swimming in the shallow seas that covered much of Europe and England along with other large marine predators. At the time, the area consisted of a chain of islands. They believe T. lythrodectikos would have been a very strong swimmer it had a fluked tail and forelimbs that resembled flippers and was able to open its mouth very wide to allow for biting into large prey. It would have been both a formidable hunter and an elusive target for other larger marine animals. But if caught, would not have been difficult to eat as it lacked the bony armor of other species of the time. 

The Middle Jurassic period, as has been glamorized by Hollywood, was a time during which many very large animals existed, many of them predatory. Their existence, scientists say, indicates a time when there was a very healthy food chain. 

The team adds that the species is the oldest known super-predator, and notes that little research had been done on the skeletal remains over the near century since it was brought to the museum. They also report that no stomach contents were found, thus they can't say for sure what the animal ate.