Wednesday, 22 February 2017

Hydrolagus erithacus: New Species of Ghost Shark Discovered

Photo of the Hydrolagus erithacus ghost shark
Kristin Walovich holds the newly described species of ghost shark
Photo Credit: Kristin Walovich

Researchers recently announced the discovery of a new species of ghost shark, Hydrolagus erithacus. Ghost sharks - which aren’t actually sharks but instead their closest living relatives - are an extraordinarily rare sighting. Actually, it was just a few months ago, when a ghost shark was filmed alive in a natural habitat for the first time! The new species is the second largest ever recorded, and the 50th species of ghost shark so far.

Also known as chimaeras, rat fish, spook fish and rabbit fish, ghost sharks have been around since before the dinosaurs, having branched off from sharks nearly 400 million years ago and have remained isolated ever since. Researchers put the new species into the Hydrolagus genus, which basically means water rabbit. "(In Greek, "hydro" means "water" and "lagus" means "rabbit" or "hare.") The species was named this way because it has an interesting set of teeth that can only be described as buckteeth. As for the species name "erithacus", it is the genus name for robin birds in honor of Robin Leslie of the South African Department of Agriculture, Forestry and Fisheries, who helped Walovich study the ghost shark.

So far, the genus contains three other species, all found in the same area with H. erithacus between South Africa and Antarctica in the southeastern Atlantic and southwestern Indian Oceans. These species are H. africanus, H. mirabilis and H. cf. trolli

Basic anatomic illustration of Hydrolagus erithacus
An illustration of Hydrolagus erithacus showing the creature's pectoral fins, used to propel itself forward.


Fishermen who accidentally catch ghost sharks on a semi-frequent basis, have been saying for years that H. erithacus individuals didn't look like the other known ghost sharks.

"The scientists and the fishermen in South Africa knew this was not the same species because Hydrolagus africanus [another ghost shark in the same genus] is small, it’s brown, and this one was huge and really dark in color. Just visibly, they were definitely different species." Kristin Walovich, a graduate student at the Pacific Shark Research Center and main author of the study.


The abstract of the study describing the new species reads:

A new species of chimaerid, Hydrolagus erithacus sp. nov., is described from nine specimens collected from the southeast Atlantic and southwest Indian oceans from depths of 470–1,000 meters. This species is distinguished from all other Hydrolagus species based on the following characteristics: head bulky, relatively large, followed by stocky body; head and body height from about pectoral fin origin to pelvic fin origin similar, then tapering rapidly to filamentous tail; first dorsal fin spine height about equal to, or slightly less than first dorsal fin apex height; second dorsal fin up to 81% of total body length and uniform in height; trifurcate claspers forked for approximately 20% of total length; robust frontal tenaculum nearly uniform in width, prepelvic tenaculae with five to seven medial spines, and a uniform black coloration with robust, non-deciduous skin. Comparison of mitochondrial NADH2 gene sequences with other morphologically similar Hydrolagus species suggests that H. erithacus is a distinct species.

References
- Walovich KA, Ebert DA, & Kemper JM (2017). Hydrolagus erithacus sp. nov. (Chimaeriformes: Chimaeridae), a new species of chimaerid from the southeastern Atlantic and southwestern Indian oceans. Zootaxa, 4226 (4) PMID: 28187604

Sunday, 19 February 2017

This Is Why Squids End up with Mismatched Eyes

Deep sea creatures come with all kinds of strange features that help them to survive their cold, dark habitat.. Some have eyes the size of a basketball, others come with appendages that blink and glow, deep-sea dwellers have developed some strange features and the "cockeyed" squid Histioteuthis heteropsis has one normal eye and one giant, bulging, yellow eye.

Histioteuthis heteropsis
One eye is normal and one is big, yellow and  bulging

Now, biologists say they have gathered the first behavioral evidence to show the two mismatched eyes evolved to spot two different sources of light available in the deep sea. The large is adapted for gazing upwards, searching for shadows of fellow sea creatures against fading sunlight, while their small one is adapted for gazing downwards, scanning deeper water for bioluminescent flashes.

By watching cockeyed squids glide and pirouette through more than 150 undersea videos collected by the Monterey Bay Aquarium Research Institute (MBARI), Thomas has gathered the first behavioral evidence that the squids' lopsided eyes evolved to spot two very different sources of light available in the deep sea.

"You can't look at one and not wonder what's going on with them." said Duke University biologist Kate Thomas.

"The deep sea is an amazing natural laboratory for eye design, because the kinds of eyes you need to see bioluminescence are different from the kinds of eyes you need to see the basic ambient light. In the case of the Histioteuthis, this cockeyed squid, they chose one eye for each." said Sönke Johnsen, professor of biology at Duke University and senior author on the study. "


Also known as the strawberry squid for its bright pink color and smattering of seed-shaped photophores, this squid lives in a region of the ocean known as the mesopelagic or "twilight" zone, 200 to 1000 meters below the surface.


The little light reaching these depths is extremely dim, a monochromatic blue, and travels straight down from above. Often, the bioluminescent flashes of other sea creatures -- which could signal danger or potential prey -- are brighter than the ambient sunlight.

Since their discovery over a hundred years ago, cockeyed squids' mismatched eyes have puzzled biologists.

To gain insight into their behavior, Thomas, a graduate student in Johnsen's lab and lead author on the paper, combed through 30 years of videos collected by MBARI's remotely operated vehicles (ROVs), which documented 152 sightings of Histioteuthis heteropsis and nine sightings of its similar but rarer cousin, Stigmatoteuthis dofleini.

She found that these "lazy, slow-moving" squid prefer to drift through the sea in a pose that might appear upside-down to us land-lubbers -- head down and tail up -- but nearly vertical, with the big eye consistently oriented upwards, and the small eye consistently oriented downwards.

The two species examined by the team: (a) an adult specimen (ROV image),
(b) a semi-transparent juvenile specimen showing the differently sized and shaped eyes,
(c) the left and right side of a juvenile Stigmatoteuthis dofleini, and
(d) an adult S. dofleini (ROV image).

Using visual simulations, Thomas showed that, because the sunlight only comes from directly above, it would be nearly impossible for an eye angled downwards to spot silhouettes against the ambient light. Similarly, while increasing the size of an upward-facing eye a small amount greatly improves its sensitivity to dim sunlight, increasing the size of a downward-facing eye has little impact on its ability to spot bioluminescent flashes against a dark background.

"The eye looking down really only can look for bioluminescence. There is no way it is able to pick out shapes against the ambient light. And once it is looking for bioluminescence, it doesn't really need to be particularly big, so it can actually shrivel up a little bit over generations. But the eye looking up actually does benefit from getting a bit bigger." Johnsen said.

Sporting two gigantic eyes may seem like the ultimate strategy for surviving the deep dark sea. But where resources are sparse, the cockeyed squid may have stumbled upon an ingenious solution to an ocular conundrum, Thomas said.

"Eyes are really expensive to make and maintain. You want eyes just big enough to do what you need to do, but you don't want to have any bigger eyes because then you are just wasting resources." Thomas said.

The abstract of the study reads:

The light environment of the mesopelagic realm of the ocean changes with both depth and viewer orientation, and this has probably driven the high diversity of visual adaptations found among its inhabitants. The mesopelagic 'cockeyed' squids of family Histioteuthidae have unusual eyes, as the left and right eyes are dimorphic in size, shape and sometimes lens pigmentation. This dimorphism may be an adaptation to the two different sources of light in the mesopelagic realm, with the large eye oriented upward to view objects silhouetted against the dim, downwelling sunlight and the small eye oriented slightly downward to view bioluminescent point sources. 

We used in situ video footage from remotely operated vehicles in the Monterey Submarine Canyon to observe the orientation behaviour of 152 Histioteuthis heteropsis and nine Stigmatoteuthis dofleini We found evidence for upward orientation in the large eye and slightly downward orientation in the small eye, which was facilitated by a tail-up oblique body orientation. We also found that 65% of adult H. heteropsis (n = 69) had yellow pigmentation in the lens of the larger left eye, which may be used to break the counterillumination camouflage of their prey. Finally, we used visual modelling to show that the visual returns provided by increasing eye size are much higher for an upward-oriented eye than for a downward-oriented eye, which may explain the development of this unique visual strategy.This article is part of the themed issue 'Vision in dim light'.

References
- Thomas KN, Robison BH, & Johnsen S (2017). Two eyes for two purposes: in situ evidence for asymmetric vision in the cockeyed squids Histioteuthis heteropsis and Stigmatoteuthis dofleini. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 372 (1717) PMID: 28193814

Wednesday, 15 February 2017

New Species of Polychaete Worm Discovered in Antarctica

Photo of two specimens of Flabegraviera Sp.
Flabegraviera fujiae (left), the new species described in the
in the new study, and Flabegraviera mundata (right).
(Scale bar: 1cm)
A few days ago, a team of Japanese scientists from the Hokkaido University announced the discovery a new species of polychaete, a type of marine annelid worm.

The discovery took place 9-meters deep underwater near Japan's Syowa Station in Antarctica and provides a good opportunity to study how animals adapt to extreme environments.

International efforts are currently underway in Antarctica to build long-term monitoring systems for land and coastal organisms from an ecological conservation standpoint. This is why the accumulation of continent-wide fauna information is essential, but Japan is lagging behind in gathering and analyzing such data around Syowa Station, particularly in regard to coastal marine life.

To address this issue, in 2015 a team of researchers, including Keiichi Kakui, a lecturer at Hokkaido University, and Megumu Tsujimoto, a postdoctoral researcher at Japan's National Institute of Polar Research, decided to do some digging in old marine specimens stored at the institute, as well as newly collected specimens. As a part of this process, they conducted microscopic analyses to examine two annelid worms that scuba divers collected 8-9 meters deep on January 16th, 1981, at Nishinoura near Syowa Station.

The new species was found 9 meters deep and turned out to be an un-described polychaete worm, a variety with a thick, gel-like coat and conspicuous, long notochaeta. The team named the worm as Flabegraviera fujiae, naming it after the icebreaker ship "Fuji" used in the expedition in 1981. The specimen collected 8 meters deep was recognized as Flabegraviera mundata, and was deemed to have been collected at the shallowest depth ever recorded for the Flabegraviera genus.

Prof. Kentaro Watanabe (in scuba diving gear) co-author of the study and Professor Eiji Takahashi
of Yamagata University pictured at Antarctica. (Photo by the National Institute of Polar Research)

"This study is a major step forward in understanding marine life in the coastal region near Syowa Station. The Flabegraviera genus, to which the three species belong, is unique to the Antarctic and considered a good example for studying how polychaetes adapt to extreme environments." said Dr. Keiichi Kakui,

Now that it has become clear that polychaetes inhabit depths reachable by scuba divers, the researchers hope to conduct experiments using live specimens to get a better insight of the new species and the rest of the local marine life as well.

The abstract from the corresponding recent paper reads:

"A new species of polychaete, Flabegraviera fujiae sp. nov., is described and the first report of F. mundata (Gravier, 1906) from the shallow water around Syowa Station, Antarctica, is presented. Flabegraviera fujiae sp. nov. resembles F. profunda Salazar-Vallejo, 2012 but is discriminated from the latter by having eyes and an exposed cephalic cage. The specimen of F. mundata was collected from a depth of 8 m, providing the shallowest record of this species to date."

References
https://www.oia.hokudai.ac.jp/blog/new-species-discovered-in-antarctica/
- Jimi N, Tsujimoto M, Watanabe K, Kakui K, & Kajihara H (2017). A new species and the shallowest record of Flabegraviera Salazar-Vallejo, 2012 (Annelida: Flabelligeridae) from Antarctica. Zootaxa, 4221 (4) PMID: 28187651

Tuesday, 14 February 2017

Amphioctopus Marginatus: The Octopus That Pretends to Be a Coconut

Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Octopoda
Family: Octopodidae
Genus: Amphioctopus
Species: Amphioctopus  marginatus
Conservation Status: Not yet assessed
Common Name: Coconut octopus, Veined octopus

Meet Amphioctopus marginatus a medium-sized octopus found in the tropical waters of the western Pacific Ocean The species is best known as the "coconut octopus" due to its unusual affinity with...you guessed right...coconuts! Don't believe me? Check out for yourself:

Autobots, transform and roll out!




The species is also known as the veined octopus, due to the dark lines that run from head to tentacle.

Distribution & Habitat
Amphioctopus marginatus lives in the tropical western Pacific and coastal waters of the Indian Ocean on sandy bottoms in bays or lagoons at a depth range of 0 - 44 m. It frequently buries itself in the sand with only its eyes uncovered.

Description
The main body of the coconut octupus is on average about 8 cm (3 in) long and including the arms, approximately 15 cm (6 in) long. The octopus displays a typical color pattern with dark ramified lines similar to veins, usually with a yellow siphon. The arms are usually dark in color, with contrasting white suckers. In many color displays, a lighter trapezoidal area can be seen immediately below the eye.


A coconut octopus finds shelter in a glass 

Diet
Their diet mainly consists shrimps, crabs, and clams.

Behavior and habitat
Young individuals (4-5 cm diameter) use coconut and clam shells as a shelter. In 2005, researchers at the University of California, Berkeley, discovered that the species uses bipedal locomotion. It is one of only two octopus species known to display such behavior, with the other one being Abdopus aculeatus.

This behavior was observed in an area off Sulawesi, Indonesia, where the sandy bottom was littered with coconut shells. The bipedal motion appears to mimic a floating coconut. Furthermore, researchers from the Melbourne Museum in Australia have also discovered that the species uses tools for concealment and defense by gathering available debris to create a defensive fortress. This behavior was observed in individuals in Bali and North Sulawesi in Indonesia. The researchers filmed the octopus collecting coconut half-shells discarded by humans from the sea floor. They were then carried up to 20 meters (66 ft) and arranged around the body of the octopus to form a spherical hiding place similar to a clam-shell.

Coconut octops carrying its' house around :)


References
- http://www.berkeley.edu/news/media/releases/2005/03/24_octopus.shtml
- Finn JK, Tregenza T, Norman MD (2009). Defensive tool use in a coconut-carrying octopus. Curr. Biol, 19 (23) : 10.1016/j.cub.2009.10.052


Small coconut octopus using a nut shell and clam shell for shelter

Monday, 16 January 2017

Tiger cub playing with a house cat!

Here's a cute unlikely friendship that will make up your day:






Here's the caption of the video if you want to learn more about the story behind these two animals:


 "THIS IS NOT AT MY HOUSE AND I DO NOT OWN EITHER ANIMAL. THIS FOOTAGE WAS TAKEN AT AN ANIMAL RESERVE. NEITHER ANIMAL WAS HARMED. The tiger cub and house cat live together and from what I was told play together on a regular basis. Just so you know, the house cat can come and go as he pleases from the area where the tiger cub is kept. While I was there I saw that cat come and play with the cub several times, never at any time was the cat forced to play. The house cat has been around many tiger and lion cubs at the reserve throughout the years."

Friday, 13 January 2017

Phrynocephalus mystaceus: World's Weirdest Lizard?

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Iguania
Family: Agamidae
Genus: Phrynocephalus
Species: Phrynocephalus mystaceus
Conservation Status: Not yet assessed
Common Name: Secret Toad-headed Agama



This is definitely one of the weirdest looking lizards that have been featured on the site. At first, it looks pretty normal..And then it opens its mouth!

Scientifically described as Phrynocephalus mystaceus, this agamid lizard can be found in Iran, North Afghanistan, Eastern Caucasus, Kazakhstan, Uzbekistan and possibly in south of Astrakhan Oblast. With the tail straightened, adults can reach a length of up to 9,44 inches (24 cm).

Commonly known as the secret toadhead agama, the species is best known for its secret red oral display frill that unfolds when the creature is frightened by predators(hence the name). The creature will also hiss and show its teeth to deter its enemies. Well, I would probably be disgusted and leave it alone but I guess it works the same :)

Here's a video of this amazing creature, jump to 0:19 if you are impatient!



Habitat of Phrynocephalus mystaceus (orange)

Tuesday, 27 December 2016

Kitten Gets Into Owner's Mouth

Hey, what's there? Let me explore that cave in your mouth . Why won't you let me :( !