Saturday, 1 December 2018

AMMONITES OF THE CAUCAUS MOUNTAINS

A very pleasing example of the Ammonite Acanthohoplites bigoureti (Seunes, 1887). Lower Cretaceous, Upper Aptian, from a riverbed concretion, Kurdzhips River, North Caucasus Mountains, Republic of Adygea, Russia. 

Geologically, the Caucasus Mountains belong to a system that extends from southeastern Europe into Asia and is considered a border between them. The Greater Caucasus Mountains are mainly composed of Cretaceous and Jurassic rocks with the Paleozoic and Precambrian rocks in the higher regions. 

Some volcanic formations are found throughout the range. On the other hand, the Lesser Caucasus Mountains are formed predominantly of the Paleogene rocks with a much smaller portion of the Jurassic and Cretaceous rocks. 

The evolution of the Caucasus began from the Late Triassic to the Late Jurassic during the Cimmerian orogeny at the active margin of the Tethys Ocean while the uplift of the Greater Caucasus is dated to the Miocene during the Alpine orogeny.

The Caucasus Mountains formed largely as the result of a tectonic plate collision between the Arabian plate moving northwards with respect to the Eurasian plate. As the Tethys Sea was closed and the Arabian Plate collided with the Iranian Plate and was pushed against it and with the clockwise movement of the Eurasian Plate towards the Iranian Plate and their final collision, the Iranian Plate was pressed against the Eurasian Plate. 

As this happened, the entire rocks that had been deposited in this basin from the Jurassic to the Miocene were folded to form the Greater Caucasus Mountains. This collision also caused the uplift and the Cenozoic volcanic activity in the Lesser Caucasus Mountains.

The preservation of this Russian specimen is outstanding. Acanthohoplites bigoureti are also found in Madagascar, Mozambique, in the Rhone-Alps of France and the Western High Atlas Mountains and near Marrakech in Morocco. This specimen measures 55mm and is in the collection of the deeply awesome Emil Black.

Thursday, 29 November 2018

ANCIENT OCTOPUS: KEUPPIA

A sweet as you please example of Keuppia levante (Fuchs, Bracchi & Weis, 2009), an extinct genus of octopus that swam our ancient seas back in the Cretaceous. 

The dark black and brown area you see here is his ink sac which has been preserved for a remarkable 95 million years.

This cutie is in the family Palaeoctopodidae, and one of the earliest representatives of the order Octopoda — and perhaps my favourite fossil. It was this perfect specimen that inspired the logo for the Fossil Huntress brand.  

These ancient marine beauties are in the class Cephalopoda making them relatives of our modern octopus, squid and cuttlefish.

There are two species of Keuppia, Keuppia hyperbolaris and Keuppia levante, both of which we find as fossils. We find their remains, along with those of the genus Styletoctopus, in Cretaceous-age Hâqel and Hjoula localities in Lebanon. 

For many years, Palaeoctopus newboldi (Woodward, 1896) from the Santonian limestones at Sâhel Aalma, Lebanon, was the only known pre‐Cenozoic coleoid cephalopod believed to have an unambiguous stem‐lineage representative of Octobrachia fioroni

With the unearthing of some extraordinary specimens with exquisite soft‐part preservation in the Lebanon limestones, our understanding of ancient octopus morphology has blossomed. The specimens are from the sub‐lithographical limestones of Hâqel and Hâdjoula, in northwestern Lebanon. These localities are about 15 km apart, 45 km away from Beirut and 15 km away from the coastal city of Jbail. Fuchs et al. put a nice little map in their 2009 paper that I've included and referenced here.

Palaeoctopus newboldi had a spherical mantle sac, a head‐mantle fusion, eight equal arms armed with suckers, an ink sac, a medially isolated shell vestige, and a pair of (sub‐) terminal fins. The bipartite shell vestige suggests that Palaeoctopus belongs to the octopod stem‐lineage, as the sister taxon of the Octopoda, the Cirroctopoda, is characterized by an unpaired clasp‐like shell vestige (Engeser 1988; Haas 2002; Bizikov 2004).

It is from the comparisons of Canadian fauna combined with those from Lebanon and Japan that things really started to get interesting with Octobrachia. Working with fossil specimens from the Campanian of Canada, Fuchs et al. (2007a ) published on the first record of an unpaired, saddle‐shaped shell vestige that might have belonged to a cirroctopod. 

Again from the Santonian–Campanian of Canada and Japan, Tanabe et al. (2008) reported on at least four different jaw morphotypes. Two of them — Paleocirroteuthis haggarti (Tanabe et al., 2008) and Paleocirroteuthis Pacifica  (Tanabe et al ., 2008) — have been interpreted as being of cirroctopod type, one of octopod type, and one of uncertain octobrachiate type. 

Interestingly Fuchs et al. have gone on to describe the second species of Palaeoctopus, the Turonian Palaeoctopus pelagicus from limestones at Vallecillo, Mexico. While more of this fauna will likely be recovered in time, their work is based solely on a medially isolated shell vestige.

Five new specimens have been found in the well-known Upper Cenomanian limestones at Hâqel and Hâdjoula in Lebanon that can be reliably placed within the Octopoda. Fuchs et al. described these exceptionally well‐preserved specimens and discuss their morphology in the context of phylogeny and evolution in their 2008 paper (2009 publishing) in the Palaeontology Association Journal, Volume 51, Issue 1.

The presence of a gladius vestige in this genus shows a transition from squid to octopus in which the inner shell has divided into two parts in early forms to eventually be reduced to lateralized stylets, as can be seen in Styletoctopus.

The adorable fellow you see here with his remarkable soft-bodied preservation and inks sack and beak clearly visible is Keuppia levante. He hails from Late Cretaceous (Upper Cenomanian) limestone deposits near Hâdjoula, northwestern Lebanon. The vampyropod coleoid, Glyphiteuthis abisaadiorum n. sp. is also found at this locality. This specimen is about 5 cm long.

Fuchs, D.; Bracchi, G.; Weis, R. (2009). "New octopods (Cephalopoda: Coleoidea) from the Late Cretaceous (Upper Cenomanian) of Hâkel and Hâdjoula, Lebanon". Palaeontology. 52: 65–81. doi:10.1111/j.1475-4983.2008.00828.x.

Photo one: Fossil Huntress. Figure Two: Topographic map of north‐western Lebanon with the outcrop area in the upper right-hand corner. Fuchs et al, 2009.  

Wednesday, 21 November 2018

SAN JUAN ISLANDS

The San Juan Islands Archipelago, a group of 175 named islands located in Washington State is in the heart of the Salish Sea, just north of Seattle.  

If all the exposed landmasses were counted at low tide, the number would rise to 700. 

Eighty-four of these islands are designated as National Wildlife Refuges and are mostly made up of Mesozoic bedrock.

People come to the San Juans from all over the world to enjoy the remote island lifestyle, to soak up the natural world, both in sights and sounds and to have the chance to be closer to what wild places can gift them.  

Hike or bike the trails and roads, watch both sea and terrestrial birds, spend time observing whales, seals, sea lions, dolphins or porpoises from a land or water base. Opportunities to experience and learn begin as you step onto the ferry or land at the marina or airport. Natural beauty abounds and where words might fail, the sights and sounds fill in the frame. 

There are only four ferries serving the islands. The islands were formed by massive geological events, mountains moving, land shifting, volcanos erupting and glacial ice carving.  The result produced the Salish Sea, a body of water encompassing: West in the Strait of Juan de Fuca to the Pacific Ocean, North to the Georgia Strait and Canada and South to Puget Sound. 

They were formed by massive geological events, mountains moving, land shifting, volcanos erupting and glacial ice carving. The result produced the Salish Sea, a body of water encompassing: West in the Strait of Juan de Fuca to the Pacific Ocean, North to the Georgia Strait and Canada and South to Puget Sound.

Reference:

Western Prince Whale & Wildlife Tours: https://orcawhalewatch.com/san-juan-islands/

Tuesday, 20 November 2018

BEARS: URSIDAE

Bears are one of my favourite mammals. Had they evolved in a slightly different way, we might well have chosen them as pets instead of the dogs so many of us have in our lives today. 

Bears are carnivoran mammals of the family Ursidae. They are classified as caniforms or doglike carnivorans. 

Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout the Northern Hemisphere and partially in the Southern Hemisphere —  making a home in North America, South America, Europe, and Asia.

In the Kwak'wala language of the Kwakiutl First Nations of the Pacific Northwest — or Kwakwaka'wakw, speakers of Kwak'wala — a grizzly bear is known as na̱n and the ornamental grizzly bear headdress worn by the comic Dluwalakha grizzly bear dancers in the Grizzly Bear Dance, Gaga̱lalał, is known as na̱ng̱a̱mł. A black bear is known as t̕ła'yi — I do not know the word for Polar Bear in Kwak'wala.

The relatives of our black and brown bears, a dog-bear, entered the fossil record about 20 million years ago. We have found polar bear bones that tell us more about when they split off in the lineage.

DNA from a 110,000–130,000-year-old polar bear fossil has been successfully sequenced. The genome, from a jawbone found in Svalbard, Norway, in 2004, indicates when polar bears, Ursus maritimus, diverged from their nearest common relative, the brown bear — Ursus arctos.

Because polar bears live on ice and their remains are unlikely to be buried in sediment and preserved, polar bear fossils are very rare. So the discovery of a jawbone and canine tooth — the entirety of the Svalbard find — is impressive. 

But far more important, is that when molecular biologist Charlotte Lindqvist, then at the University of Oslo's Natural History Museum and now at the University at Buffalo in New York, drilled into the jaw, she was able to collect intact mitochondrial DNA. Yes, a bit Jurassic Park-esque.

Mitochondria — organelles found in animal cells — have their own DNA and can replicate. And because there are many mitochondria per cell, mitochondrial DNA is easier to find in fossils than nuclear DNA. 

Lindqvist wondered whether this mitochondrial DNA could illuminate the evolutionary history of how and when polar bears diverged from brown bears. To find out, she worked with Stephan Schuster, a molecular biologist at Pennsylvania State University in University Park, and a team of colleagues to sequence the genetic material she had collected and was successful.

It is the oldest mammalian mitochondrial genome yet sequenced — about twice the age of the oldest mammoth genome, which dates to around 65,000 years old. From Lindqvist's work, we learned that polar bears split off the lineage from brown bears about 150,000 years ago. They evolved rapidly in the Late Pleistocene, taking advantage of their hunting prowess to become the apex predators of the northern arctic region.