ORYGMASPIS SPINULA OF THE MCKAY GROUP

This calcified beauty is Orygmaspis (Parabolinoides) spinula (Westrop, 1986) an Upper Cambrian trilobite from the McKay Group near Tanglefoot Mountain in the Kootenay Rockies. 

Orygmaspis is a genus of asaphid trilobite with an inverted egg-shaped outline, a wide headshield, small eyes, long genal spines, 12 spined thorax segments and a small, short tail shield, with four pairs of spines.

The outline of the exoskeleton Orygmaspis is inverted egg-shaped, with a parabolic headshield — or cephalon less than twice as wide as long. 

The glabella, the well-defined central raised area excluding the backward occipital ring, is ¾× as wide as long, moderately convex, truncate-tapering, with 3 pairs of shallow to obsolete lateral furrows. 

The occipital ring is well defined. The distance between the glabella and the border (or preglabellar field) is ±¼× as long as the glabella. This fellow had small to medium-sized eyes, 12-20% of the length of the cephalon. These were positioned between the front and the middle of the glabella and about ⅓ as far out as the glabella is wide. 

The remaining parts of the cephalon, the fixed and free cheeks — or fixigenae and librigenae — are relatively flat. The fracture lines or sutures — that separate the librigenae from the fixigenae in moulting — are divergent just in front of the eyes. These become parallel near the border furrow and strongly convergent at the margin. 

From the back of the eyes, the sutures bend out, then in, diverging outward and backward at approximately 45°, cutting the posterior margin well within the inner bend of the spine — or opisthoparian sutures. 

The thorax or articulating middle part of the body has 12 segments. The anteriormost segment gradually narrows into a sideward directed point, while further to the back the spines are directed outward and the spine is of increasing length up until the ninth spine, while the spine on the tenth segment is abruptly smaller, and 11 and 12 even more so. 

This fellow has a wee pygidium or tail shield that is only about ⅓× as wide as the cephalon. It is narrowly transverse about 2× wider than long. Its axis is slightly wider than the pleural fields to each side, and has up to 4 axial rings and a terminal and almost reaches the margin. Up to 4 pleural segments with obsolete interpleural grooves and shallow pleural furrows. The posterior margin has 3 or 4 pairs of spines, getting smaller further to the back. 

References:

Chatterton, Brian D. E.; Gibb, Stacey (2016). Furongian (Upper Cambrian) Trilobites from the McKay Group, Bull River Valley, Near Cranbrook, Southeastern British Columbia, Canada; Issue 35 of Palaeontographica Canadiana; ISBN: 978-1-897095-79-9

Moore, R.C. (1959). Arthropoda I - Arthropoda General Features, Proarthropoda, Euarthropoda General Features, Trilobitomorpha. Treatise on Invertebrate Paleontology. Part O. Boulder, Colorado/Lawrence, Kansas: Geological Society of America/University of Kansas Press. pp. O272–O273. ISBN 0-8137-3015-5.

FOSSIL PRESERVATION: REPLACEMENT

Ancient life can be preserved as fossils in a number of ways. Replacement is one of the ways both shellfish and wood can be preserved as fossils. Replacement occurs as the original atomic composition of the living organism is replaced cell by cell by a new chemical structure. 

It is the chemical composition of the groundwater that determines what the composition of the fossil will be. A common type of replacement is silification. Silification is the process by which silica minerals such as quartz, chalcedony, and opal fill pores or replace existing minerals, rock, or wood.

Silicification occurs in the earth’s interior through the action of hydrothermal and cold water saturated with silica. As aluminosilicate rock is weathered, a great deal of silica is freed and dissolves. Much of the dissolved silica is carried to the sea, but in places, it moves downward and replaces various rock. 

Hydrothermally silicified carbonate rock is frequently associated with ores of mercury, antimony, and other nonferrous metals. At ordinary temperatures, loose rock on the bottom of lakes and seas is subject to silicification, as is solid rock; this occurs most frequently with limestones and dolomites, more rarely with clays and phosphorites. 

Accumulations of fine-grained quartz form when carbonate rocks are replaced and aggregates of quartz and chalcedony develop when clayey rock is replaced. The presence of fine-grained quartz and quartz and chalcedony aggregates in ultrabasic rock indicates that deposits of silicate ores of nickel and cobalt may be found. Excellent examples of silification are fossil molluscs and petrified forests.

DINOSAURS OF THAILAND

This beautiful dinosaur track is from Kalasin Dinosaur Park in northeastern Thailand. 

Thailand boasts some of the finest Mesozoic trackways from five endemic dinosaur species.  

Since 1976, the Department of Mineral Resources with Thai-French Paleontological Project had continuously investigated the dinosaurs in the Phu Wiang mountains. The project found so many vertebrae, teeth, and footprints of the dinosaurs mainly from the sandstones of the Early Cretaceous Sao Khua Formation (about 130 million years old). These include sauropods and theropods ranging in size from adorable chickens to beasties up to 15 meters long. 

The Thai dinosaur record from the continental rocks of the Khorat Plateau is the best in Southeast Asia. The oldest footprints are those from small dinosaurs from the Middle to Late Jurassic Phra Wihan Formation. The most varied dinosaur assemblages come from the Late Jurassic Sao Khua Formation. Here we see the sauropods dominate the fossil beds interspersed with a variety of theropods. Large theropod footprints are known from the Early Cretaceous Phu Phan Formation. Theropods and the primitive ceratopsian Psittacosaurus occur in the Aptian-Albian Khok Kruat Formation. We find dinosaur material further north along the Mekong River region of Laos. Thai fossils show a close relationship to those found in China and Mongolia. 

If you'd like to go visit them, there is a rather nice display at the Phu Wiang Dinosaur Museum in the newly established Wiang Kao district about 80 kilometres to the west of the provincial capital of Khon Kaen. They have several species on display, including: Phuwiangosaurus sirindhornae, Siamosaurus suteethorni, Siamotyrannus isanensis, Kinnareemimus khonkaenensis, Compsognathus (awe, a wee vicious chicken...) and, of course, the Phu Wiang dinosaur footprints.

If you'd like to visit Kalasin Dinosaur Park, follow route 227 towards Lam Pao Dam and Dok Ket Beach. Instead of turning left towards the dam, continue up towards Sirindhorn Dinosaur Museum. You'll see it on your left about 5km before the museum. For some GPS help, pop this into Google Maps: Dinosaur Park, Ni Khom, Sahatsakhan District, Kalasin 46140, Thailand.

References: 

• Ingavat, R., Janvier, R., and Taquet, P. (1978) Decouverte en Thailande d'une portion de femur de dinosaure sauropode (Saurischia, Reptilia). C.R. Soc.Geol.France 3: 140-141
• Wickanet Songtham and Benja Sektheera (2006) Phuwiangosaurus sirindhornae Bangkok: Department of Mineral Resources: 100 pages
• Buffetaut, E., Suteethorn, V., and Tong, H. (2009) An earliest 'ostrich dinosaur' (Theropoda: Ornithomosauria) from the Early Cretaceous Sao Khua Formation of NE Thailand, pp. 229-243, in E. Buffetaut, G. Cuny, J. Le Loeuff, and V. Suteethorn (eds.), Late Palaeozoic and Mesozoic Ecosystem in SE Asia. Geological Society, London, Special Publication 315.

PARASAUROLOPHUS WALKERI OF ALBERTA

Holotype Specimen of P. walkeri, Royal Ontario Museum

Closer to home, we can find species of Parasaurolophus walkeri in the Dinosaur Park Formation of Alberta, Canada. 

The Dinosaur Park Formation is the uppermost member of the Belly River Group — also known as the Judith River Group, a major geologic unit in southern Alberta. 

It is an area rich in fossils. The formation contains dense concentrations of dinosaur skeletons, both articulated and disarticulated, often found with preserved remains of soft-tissues. Remains of other animals such as fish, turtles, and crocodilians, as well as plant remains, are also abundant. The formation has been named after Dinosaur Provincial Park, a UNESCO World Heritage Site where the formation is well-exposed in the badlands that flank the Red Deer River.

The Dinosaur Park Formation was deposited during the Campanian stage of the Late Cretaceous, between about 76.9 and 75.8 million years ago in what was an alluvial and coastal plain environment. It is bounded by the nonmarine Oldman Formation below and the marine Bearpaw Formation above.

The formation includes diverse and well-documented fauna including dinosaurs such as the horned Centrosaurus, Chasmosaurus, and Styracosaurus, fellow duckbills Gryposaurus and Corythosaurus, the mighty tyrannosaurid Gorgosaurus, and armoured Edmontonia, Euoplocephalus and Dyoplosaurus. 

Dinosaur Park Formation is interpreted as a low-relief setting of rivers and floodplains that became more swampy and influenced by marine conditions over time as the Western Interior Seaway transgressed westward. The climate was warmer than present-day Alberta, without frost, but with wetter and drier seasons. Conifers were apparently the dominant canopy plants, with an understory of ferns, tree ferns, and angiosperms.

Some of the less common hadrosaurs in the Dinosaur Park Formation of Dinosaur Provincial Park, such as Parasaurolophus, may represent the remains of individuals who died while migrating through the region. They might also have had a more upland habitat where they may have nested or fed. The presence of Parasaurolophus and Kritosaurus in northern latitude fossil sites may represent faunal exchange between otherwise distinct northern and southern biomes in Late Cretaceous North America. Both taxa are uncommon outside of the southern biome, where, along with Pentaceratops, they are predominant members of the fauna.

Photo: Holotype Specimen: The incomplete Parasaurolophus walkeri type specimen in the Royal Ontario Museum. Location: 43° 40′ 5.09″ N, 79° 23′ 40.59″ W. Shared by MissBossy.

GASTROPOD OF THE ITALIAN PENINSULA

A beautiful example of two water-worn specimens of the gastropod Persististrombus latus (Gmelin, 1791) captured after a storm captured by the deeply awesome José Juárez Ruiz from Palma De Mallorca, Spain.

In his original description of Strombus latus, Gmelin describes this new species in his paper from 1791, page 3520: "latus. 35. Str. testae labro prominulo inferne bis emarginato, spirae anfractu primo medio laevi utrinque transversim striato, reliquis nodis obtusis coronatis."

Persististrombus latus is the most iconic representative of the Senegalese fauna, a fossil assemblage of tropical water organisms thought to have colonized the Mediterranean Sea during the last interglacial period.

This lovely Eocene gastropod has become an important stratigraphic marker of Marine Isotope Stage (MIS) 5.5, which allows for the correlation of raised coastal deposits, useful in studying sea-level variations and tectonic uplift.

Persististrombus latus is found in shallow marine sediments of Tyrrhenian age (∼124 ka) in several localities of the Italian peninsula. Gmelin's early work on the species is from upper Pleistocene deposits of the marine terraces of the Crotone peninsula of southern Italy. If you fancy a visit to this locality, head to: N38°45'00" - N39°04'60", E17°04'60" - E17°19'60".

Commonly known as the Bubonian Conch, this species of sea snail is a marine gastropod mollusk in the family Strombidae, the true conchs. These fellows are herbivorous, dining on wee bits of algae, seagrass and other detritus found along the seafloor. They grow to around 2.76" - 6.5" (7cm - 16.5cm). We find them in the fossil record and also as modern shells in the Atlantic Ocean along West Africa, Senegal, Gabon, Cape Verde, Ascension Island and Angola. They like it warm, preferring seas of 57.2 °F - 68 °F (14°C - 20°C).

Ronald Nalin, Valentina Alice Bracchi, Daniela Basso, Francesco Massari; Persististrombus latus (Gmelin) in the upper Pleistocene deposits of the marine terraces of the Crotone peninsula (southern Italy). Italian Journal of Geosciences ; 131 (1): 95–101. doi: https://doi.org/10.3301/IJG.2011.25

Gmelin J.F. (1791). Vermes. In: Gmelin J.F. (Ed.) Caroli a Linnaei Systema Naturae per Regna Tria Naturae, Ed. 13. Tome 1(6). G.E. Beer, Lipsiae [Leipzig]. pp. 3021-3910.

NUMMULITES OF THE PYRAMIDS

Built to endure the tests of time, the pyramids of Giza were built of limestone, granite, basalt, gypsum (mortar), and baked mud bricks quarried at Giza and sites further up the river Nile at Aswan.

Together they form some of the oldest (and last remaining) wonders of the ancient world. The great pyramids of Giza, with their smooth exteriors carved from fine grain white limestone quarried at Tura on the Giza-plateau, are built from stone that speaks of Egypt's much older geologic history.

The limestone from Tura was the finest and whitest of all the Egyptian quarries and chosen for the facing stones for the richest tombs. It is interesting in that it is made up almost entirely of Nummulites, a lovely single-celled organism. Nummulites (Lamarck, 1801) are the calcareous chambered shells (tests) of extinct forms of marine, amoeba-like organisms  — protozoans or protists — called foraminifera that accumulated in huge quantities during the early Cenozoic. They look very much like little white, round crackers or cross-sections of plants with their concentric rings.

Imagine millions of them with their wee calcium carbonate skeletons living, dying and sinking to the seafloor. Over time, these little lovelies gathered in layers, pressure and time doing the rest. They became cemented together and helped form some of the most beautiful limestones we have today. It is remarkable to think that Khufu or Cheops, the Great Pyramid of Egypt, the oldest and largest of the pyramids at Giza built back in the 4th dynasty golden age and the only remaining wonder of the ancient world, is made up of teeny, tiny single-celled fossils — mindblowing!

They are commonly found as fossils in Eocene to Miocene marine rocks, particularly around southwest Asia and the Mediterranean — including the Eocene limestones of Egypt that lived in the Tethys sea.

Fossil Nummulites / Urbasa, Navarre

Foraminifera are still alive in our oceans, though none quite as large as Nummulites. Nummulites vary in diameter from very small, just 1.3 cm (0.5 inches) to 5 cm (2 inches) but grew much larger, up to six inches wide back in the Middle Eocene.

The small size of most cells has to do with how they move the nutrients they need across their cell membrane — a process called diffusion. Nummulites grew much larger, six inches is mighty big for a single-celled organism, because of their overall design. They evolved to increase their surface area and create a greater opportunity for diffusion. Clever.

In our modern Nummulites, we see a symbiotic relationship with algae that allowed them to grow much larger. Each of these little fellows has a community of them living with him. Lorraine Casazza, a University of California at Berkeley paleontologist did some great work on the nummulites from Egypt.

For the central chamber, with the sarcophagus of the pharaoh, lovely reddish-pink granite from Aswan was used. The granite helped to take the weight of this massive construction. The ancient Egyptians also used nummulite shells as coins. It is not surprising then that the name "Nummulites" is a diminutive form of the Latin nummulus meaning "little coin," a direct reference to their shape and usage.

A Nummulite Protozoan Foraminiferan

Back in 2013, archaeologists made an unlikely find in a cave seven hundred kilometres from Giza. Their find, a 4,600-year-old papyrus scroll, details an ancient shipload of rock, likely destined for  Khufu's pyramid, the pyramid that would later be known as the Great Pyramid of Giza.

The papyrus is addressed to Ankh-haf, Khufu’s half-brother, and describes the undertaking of an expedition by a 200-man crew to the limestone quarries near Tura, on the eastern shore of the Nile. After loading the blocks onto their ship, the expedition indented to float down the river Nile for a successful delivery. They were then joined by another 100,000 slaves who had the unenviable task of unloading the 2-3 ton blocks of limestone built from nummulites, then pulling them across ramps to be dragged to the construction site.

It is amazing to have documentation from the 4th dynasty and poetic that this shipping order should be for materials, immortalized first as nummulites in the Eocene, excavated, carved and immortalized at Giza.

Herodotus' Histories, Book VIII

The Greek historian Herodotus visited Egypt during the construction of Khufu's pyramid by more than 100,000 slaves. Herodotus wasn't a fan of Khufu, describing him as a cruel tyrant.

In his literary work Historiae, Book II, chapter 124–126, Herodotus writes: "As long as Rhámpsinîtos was king, as they told me, there was nothing but orderly rule in Egypt, and the land prospered greatly. But after him Khéops became king over them and brought them to every kind of suffering: He closed all the temples; after this he kept the priests from sacrificing there and then he forced all the Egyptians to work for him.

So some were ordered to draw stones from the stone quarries in the Arabian mountains to the Nile, and others he forced to receive the stones after they had been carried over the river in boats, and to draw them to those called the Libyan mountains. And they worked by 100,000 men at a time, for each three months continually. Of this oppression there passed ten years while the causeway was made by which they drew the stones, which causeway they built, and it is a work not much less, as it appears to me, than the pyramid.

For the length of it is 5 furlongs and the breadth 10 fathoms and the height, where it is highest, 8 fathoms, and it is made of polished stone and with figures carved upon it. For this, they said, 10 years were spent, and for the underground chambers on the hill upon which the pyramids stand, which he caused to be made as sepulchral chambers for himself in an island, having conducted thither a channel from the Nile."

It is estimated that 5.5 million tonnes of nummulites limestone, 8,000 tonnes of granite (imported from Aswan), and 500,000 tonnes of mortar were used in the construction of the Great Pyramid. Built by an evil genius, yes, but stunning none-the-less. Unintentionally, it may have been one of the largest — and arguably cruellest — paleontological excavations ever attempted.

Photo of Fossil nummulites in Urbasa, Navarre by Theklan - Own work, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=1125411

Photo: Nummulites from above and horizontally bisected by R A Lydekker - Life and Rocks, Public Domain, https://commons.wikimedia.org/w/index.php?curid=3048471

Photo: Fragment from Herodotus' Histories, Book VIII on Papyrus Oxyrhynchus 2099, Early 2nd Century AD. Papyrology Rooms, Sackler Library, Oxford

References: Nummulite', Tiscali Dictionary of Animals, retrieved 17 August 2004
Hottinger, Lukas (2006-09-08). "Illustrated Glossary of terms used in foraminiferal research". Paleopolis. Retrieved 2018-11-11.

Reference: Lorraine Casazza, UCMP: https://ucmp.berkeley.edu/science/fieldnotes/casazza_0711.php

Fancy a visit to Cheops? Visit: 29°58′45″N 31°08′03″E

EGYPT: SINAI PENINSULA

Much of Egypt's history is carved in her rock. We think of Egypt as old, with remarkable human history, but the land that formed this part of the world tells us of a much older time in the Earth's past.

Egypt, officially the Arab Republic of Egypt, is a country in the northeast corner of Africa, whose territory in the Sinai Peninsula extends beyond the continental boundary with Asia.

Egypt is bordered by the Gaza Strip (Palestinian territories) and Israel to the northeast, the Gulf of Aqaba and the Red Sea to the east, Sudan to the south, Libya to the west, and the Mediterranean Sea to the north. Across the Gulf of Aqaba lies Jordan, across the Red Sea lies Saudi Arabia, and across the Mediterranean Sea lie Greece, Cyprus and Turkey, although none of these share a land border with Egypt.

Five hundred kilometres southwest of Cairo, the flat sabkha plain stretches in all directions covered by a small layer of dark, round pebbles. There are spectacular limestone pillars dotting the landscape of the wonderful karst topography. This land, once the breadbasket of Egypt and the stomping ground of the Pharaohs, is now ruled by pipelines and rusted-out trucks abandoned as wrecks marking the passage of time. Beneath the sand, rust and human history lie some very interesting geology. This rock has been sculpted both through erosion and at the hands of her craftsmen.

The rock here was formed when the Earth's crust was just beginning to cool, 4 to 2.5 billion years ago, during the Archaean. Other rock dates back to the Proterozoic when the Earth's atmosphere was just beginning to form. The oldest of these are found as inliers in Egypt’s Western Desert. The rocks making up the Eastern Desert are largely late Proterozoic in age, the time when bacteria and marine algae were the principal forms of life.

Throughout the country, this older basement is overlain by Palaeozoic sedimentary rocks. Cretaceous outcrops are common. We also find sediments that tell a story of repeated marine transgression and regressions, sea levels rising and falling, characteristic of the Cenozoic. It is from Egypt's Cenozoic geology that we get the limestones used for the great pyramids.

WASHINGTON STATE PALEONTOLOGY

North Cascades National Park, Washington State, USA

Over vast expanses of time, powerful tectonic forces have massaged the western edge of the continent, smashing together a seemingly endless number of islands to produce what we now know as North America and the Pacific Northwest.

Washington is home to a wide variety of fossils—from new species of fossil crabs to marine mollusks and the fossil palm fronds that symbolize the Chuckanut formation.

We also find fossil whales, bird trackways, fossil sockeye salmon, mammal footprints, mammoth bones & the trace fossil remains of ancient rhino. In the time expanse in which we live our very short human lives, the Earth's crust appears permanent.

A fixed outer shell – terra firma. Aside from the rare event of an earthquake or the eruption of Mount St. Helen’s in 1980, our world seems unchanging, the landscape constant. In fact, it has been on the move for billions of years and continues to shift each day. As the earth’s core began cooling, some 4.5 billion years ago, plates, small bits of continental crust, have become larger and smaller as they are swept up in or swept under their neighbouring plates. Large chunks of the ocean floor have been uplifted, shifted and now find themselves thousands of miles in the air, part of mountain chains far from the ocean today or carved by glacial ice into valleys and basins.

Two hundred million years ago, Washington was two large islands, bits of the continent on the move westward, eventually bumping up against the North American continent and calling it home. Even with their new fixed address, the shifting continues; the more extreme movement has subsided laterally and continues vertically. The upthrusting of plates continue to move our mountain ranges skyward, the path of least resistance.

Fossil Palm Front, Washington State

This dynamic movement has created the landscape we see today and helped form the fossil record that tells much of Washington’s relatively recent history – the past 50 million years. Chuckanut Drive is much younger than other parts of Washington.

The fossils found there lived and died some 40-55 million years ago, very close to where they are now, but in a much warmer, swampy setting. The exposures of the Chuckanut Formation were once part of a vast river delta; imagine, if you will, the bayou country of the Lower Mississippi.

The siltstones, sandstones, mudstones and conglomerates of this formation were laid down about 40-54 million years ago during the Eocene epoch, a time of luxuriant plant growth in the subtropical flood plain that covered much of the Pacific Northwest.

This ancient wetland provided ideal conditions to preserve the many trees, shrubs, and plants that thrived here. Plants are important in the fossil record because they are more abundant and can give us a lot of information about climate, temperature, the water cycle, and humidity of the region. The Chuckanut flora is made up predominantly of plants whose modern relatives live in tropical areas such as Mexico and Central America.

Shore Bird Trackway, Washington State

While less abundant, evidence of the animals that called this ancient swamp home are also found here. Rare bird, reptile, and mammal tracks have been immortalized in the outcrops of the Chuckanut Formation.

Tracks of a type of archaic mammal of the Orders Pantodonta or Dinocerata (blunt foot herbivores), footprints from a small shorebird, and tracks from an early equid or webbed bird track give evidence to the vertebrates that inhabited the swamps, lakes and riverways of the Pacific Northwest 50 million years ago.

Fossil mammals from Washington do get most of the press. The movement of these celebrity vertebrates captured in the soft mud on the banks of a river, one of the depositional environments favourable for track preservation.

The bone record is actually far less abundant than the plant record, except near shell middens, given the preserving qualities of calcium and an alkaline environment. While calcium-rich bones and teeth fossilize well, they often do not get laid down in a situation that makes this possible. Hence the terrestrial paleontological record of Washington State at sites like Chuckanut is primarily made up of plant material.

CLALLAM BAY MARINE FAUNA

Panopea abrupt (Conrad, 1894)

This lovely large fossil bivalve is Panopea abrupta (Conrad, 1849) an extinct species of marine mollusc in the family Hiatellidae, subclass Heterodonta.

This fossil specimen was collected from lower Miocene deposits in the Clallam Formation on the foreshore bordering the Strait of Juan de Fuca near Clallam Bay, Olympic Peninsula, northwestern Washington. The oldest recorded specimen of one of their modern relatives lived not too far from here in the Strait of Juan de Fuca. That lovely was an impressive 168 years old.

A geoduck sucks water containing plankton down through its long siphon, filters this for food and ejects its refuse out through a separate hole in the siphon. Adult geoducks have few natural predators, which may also contribute to their longevity.

In Alaska, sea otters and dogfish have proved capable of dislodging geoducks; starfish also attack and feed on the exposed geoduck siphon.

Clallam Bay is a sleepy little town on the northwestern edge of the Olympic Peninsula. It was founded back in the 1880s as a steamboat stop and later served as a Mill town. If you are planning to visit the fossil exposures, head to the edge of town where it meets the sea.

Once at the water's edge, head east along the shore until you can go no further. You'll find marine fossils in the sandstone on the shore and cliffs. Mind the tide as access to the fossil site is only possible at low or mid-tide. You'll have to swim for it if you time it poorly. Clallam Bay: 48°15′17″N 124°15′30″W.

Near this site, there are many additional fossil localities to explore. In Sequim Bay, you can find Pleistocene vertebrates as well as Miocene cetacean bones near Slip Point. Near the Twin Post Office, you can find Oligocene nautiloids and bivalves (2.5km west in the bluff); You can find crabs including, Branchioplax in the Eocene limestone concretions from Neah Bay.

References: Addicott, Warren. Molluscan paleontology of the lower Miocene Clallam Formation, northwestern Washington, Geological Survey Paper 976.

FOSSIL FAUNAS OF THE PACIFIC NORTHWEST

Vertipecten fucanus (Dall, 1898), Clallam Formation, WA

Some water-worn samples of the fossil bivalve Vertipecten fucanus from Lower Miocene deposits in the Clallam Formation.

These lovelies were collected on the foreshore near Clallam Bay, Olympic Peninsula, northwestern Washington on a lovely fossil field trip I did with my mother years ago.

Range zones of pectinid bivalves provide a principal means of age determination and correlation of shallow-water, inshore facies from California, through to Washington state and up to the head of the Gulf of Alaska.

Until Addicott's study from 1976, the area was considered middle Miocene. The new Lower Miocene designation can be credited in large part to the restricted stratigraphic range of Vertipecten fucanus (Dall, 1898) and the restricted and overlapping ranges of several other fossil mollusks collected from Alaska to California.

Neogene marine sediments of the West Coast of North America were deposited in a series of widely spaced basins that extended geographically from the western and northern Gulf of Alaska (60°N) to southern California (33°N). Rich molluscan faunas occur extensively throughout these deposits and form the basis for biostratigraphic schemes that are useful for correlating within and between individual basins.

Arturia angustata nautiloid, Clallam Formation, WA

Early biostratigraphic work was concerned with faunas from particular horizons and with the stratigraphic range of diverse taxa, such as Pecten and Turritella, without reference to other fossil groups.

Succeeding work increasingly dealt with the relationships of molluscan zones to benthic and, later, planktonic foraminiferal stages. In recent years the age limits of Neogene molluscan stages have become better documented by reference to planktonic microfossils from dated DSDP cores and onshore faunas. As our tools get better, our insight into these faunal groups and their correlation with their cousins to the south and over in the Pacific become clearer.

Neogene molluscan faunas from California, the Pacific Northwest states (Oregon and Washington), and southern Alaska have been treated separately due to differences in faunal composition and geographic isolation. As a result, a different biostratigraphic sequence has been described for each region.

Pacific Northwest stages have been formally named and defined. This naming structure is also used informally for Alaskan faunas. California Neogene stages were proposed early in this century, are in need of redescription, and their usage is informal. Precise correlations between the three regional sequences have not yet been achieved, due to the low number of co-occurring species and the general lack of planktonic microfossils in these largely shallow-water faunas. The objectives of ongoing research include the documentation of the faunas of California and Pacific Northwest stages; formal description of California stages; an improved correlation between regional stage sequences; refinement of age estimates for stage boundaries; and, the establishment of Neogene stages for Alaskan faunas.

PACHYDISCUS SUCHIAENSIS

Pachydiscus suchiaensis

The late Cretaceous ammonite Pachydiscus suchiaensis found in concretion amongst the 72 million-year-old grey shales of the Northumberland Formation, Campanian to the lower Maastrichtian, part of the upper Cretaceous, from Collishaw Point (Boulder Point to the locals), northwest side of Hornby Island, southwestern British Columbia.

Hornby is a glorious place to collect. The island is beautiful in its own right and the fossils from here often keep some of their original shell or nacre which makes them quite fetching.

This fellow is found amongst gastropods, shark teeth, fossil crabs, baculites and other bivalve fossils.

Like most of the fossils found at this locality, the specimen was found in concretions rolled smooth by time and tide. The concretions you find on the beach are generally round or oval in shape and are made up of hard, compacted sedimentary rock. If you are lucky, when you split them you see a fossil hidden within. The main topographic feature on Hornby Island is an arcuate mountain consisting of the resistant cliff-forming Geoffrey formation.

Near Shingle Spit about half a mile from the coast is Mount. Geoffrey 920-foot peak; from there the mountain gradually drops in elevation to the southeast and to the north.  It consists of a structurally simple 700-foot conglomerate homocline striking N 20° W and dipping to the northeast at a shallow angle of about 6°. The apex of the arcuate mountain belt points to the southwest.

Behind the mountain and almost enclosed by it is the fertile, green Strachan Valley. On the large peninsula which extends in a southeast direction from the north of the island towards St. John’s Point, the Hornby Formation outcrops forming the cliffs on the east side of Tribune Bay. The highest of these is about 200 feet. The argillaceous Lambert and Spray formations form the subdued lowlands of the island.

The coast of Hornby is probably a rising shoreline, as indicated by the almost perpendicular cliffs along its periphery. A hundred (100) foot cliffs of Lambert shale extends from Shingle Spit to Phipps Point, while from the latter to Boulder Point, the cliffs are not as steep and are covered in many places by vegetation.

ALBERTONECTES OF THE WESTERN INTERIOR SEAWAY

Albertonectes vanderveldei

During the Cretaceous, the Western Interior Seaway split North America into two landmasses. Part of the seaway was the Bearpaw Sea, a warm, shallow body of water that covered 1.7 million square kilometres of the coastal plain about 74 million years ago.

The Bearpaw Formation is a geologic formation of Late Cretaceous (Campanian) age. It outcrops in the U.S. state of Montana, as well as the Canadian provinces of Alberta and Saskatchewan, and was named for the Bear Paw Mountains in Montana. It includes a wide range of marine fossils, as well as the remains of a few dinosaurs. It is known for its fossil ammonites, some of which are mined in Alberta to produce the organic gemstone ammolite.

It was home to many marine reptiles, ammonites, fish, and other aquatic life. Elasmosaurs —long-necked plesiosaurs — were one group of marine reptiles that inhabited these ancient waters.

They were primarily fish eaters, and used their long necks to strike at fish, then trapped them in their interlocking teeth. A new genus and species of elasmosaur, Albertonectes vanderveldei, was uncovered in 2007 during ammonite shell mining.

Albertonectes has 76 neck vertebrae, the most of any animal known — compare this to giraffes that only have seven neck vertebrae. Albertonectes had a neck that was 6.5 metres long. Was it flexible and able to bend sharply and quickly? Or was it stiff, with a gentle arc that could cover a large area? Palaeontologists used computer modelling to study the neck’s flexibility. The neck broke into four segments when it collapsed on the seafloor.

This incredible specimen provides insight into what marine communities were like during the Cretaceous Period. The fossilized remains of other animals that lived alongside Albertonectes are found in the rocks formed at the bottom of the Bearpaw Sea. These included potential prey such as small fishes, ammonites, and crayfish. From recovered shark teeth, and tooth marks left on the bone, palaeontologists determined that the carcass of Albertonectes. was scavenged by one or more sharks.

More on this impressive find:
https://royaltyrrellmuseum.wpcomstaging.com/./albertonecte…/

Photo: Roland Tanglao from Vancouver, Canada - 5d-dinosaur-camp-day2-20120802-64.jpgUploaded by FunkMonk, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=20902049

SAUROPTERYGIAN REPTILES

Libonectes atlasense / Andy Chua Collection

A beautifully preserved mandible of Libonectes atlasense, an elasmosaurid plesiosaur from early Turonian, Upper Cretaceous,  deposits of the Akrabou Formation near Asfla Village, Goulmima, Errachidia Province in eastern central Morocco.

The collecting area is in the region of Drâa-Tafilalet. You may know Errachidia as Ksar Souk. It was renamed My Rachid, in honour of the Moroccan royal family. Libonectes is a genus of sauropterygian reptile belonging to the plesiosaurs. Specimens have been found in the Britton Formation of Texas and the Akrabou Formation of Morocco.

Sauropterygian reptiles were a diverse taxon of extinct aquatic reptiles that arose from terrestrial ancestors just after the Permian extinction event. They flourished during the Triassic then all but the plesiosaurs became extinct at the end of the Triassic — with the plesiosaurs dying out at the end of the Cretaceous.

The holotype of Libonectes atlasense is an almost complete skeleton from Upper Cretaceous (mid-Turonian) rocks of the Goulmima area in eastern Morocco. Sven Sachs from the Naturkunde-Museum Bielefeld and Benjamin P. Kear from Uppsala University co-authored a paper redescribing the elasmosaurid plesiosaurian Libonectes atlasense from the Upper Cretaceous of Morocco. They did an initial assessment of the specimen in 2005, proposing a generic referral based on stratigraphical contemporaneity with Libonectes morgani from the CenomanianeTuronian of Texas, U.S.A.

Relative differences in the profile of the premaxillary-maxillary tooth row, position of the external bony nasal opening, number of teeth and rostrad inclination of the mandibular symphysis, proportions of the axial neural arch, and number of cervical and pectoral vertebrae were used to distinguish between these species.

Libonectes Scale Drawing / Hyrotrioskjan

As part of an on-going comparative appraisal of elasmosaurid plesiosaurian osteo-anatomy, they re-examined the type and formally referred material of both L. atlasense and L. morgani in order to establish species validity, as well as compile a comparative atlas for use in future works.

Their work revealed that these reportedly distinct species-level fossils are in fact virtually indistinguishable in gross morphology.

Indeed, the only substantial difference occurs in relative prominence of the midline keel along the mandibular symphysis, which might be explained by intraspecific variation. Their observations permit an amendment to the published generic diagnosis of Libonectes with the confirmation of important states such as the likely presence of a pectoral bar, distocaudad expansion of the humerus, and an epipodial foramen.

And we see some entirely new features. Novel features include a prominent ‘prong-like’ ventral midline process on the coracoids and the development of a median pelvic bar that encloses a central fenestration. Their work shows that the composite remains of L. morgani thus constitute one of the most complete elasmosaurid skeletal hypodigms documented worldwide, and evidence a trans-Atlantic distribution for this apparently dispersive species during the early Late Cretaceous. The impressive mandible you see here is in the collection of Andy Chua.

Sachs, Sven and Kear, Benjamin. (2017). Redescription of the elasmosaurid plesiosaurian Libonectes atlasense from the Upper Cretaceous of Morocco. Cretaceous Research. 74. 205-222. 10.1016/j.cretres.2017.02.017.

Photo: Libonectes atlasense specimen, Andy Chua

Drawing By Hyrotrioskjan - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=57716018

YORKSHIRE ICHTHYOSAUR TAIL

Ichthyosaur Tail Section. Photo: Liam Langley

A beautiful piece of ichthyosaur tail section found on the Yorkshire Coast in 2019 by the deeply awesome Liam Langley.

Ichthyosaurus are an extinct marine reptile first described from fossil fragments found in 1699 in Wales. Shortly thereafter, fossil vertebrae were published in 1708 from the Lower Jurassic and the first member of the order Ichthyosauria to be discovered.

Over time, we discovered a number of these fossil specimens and a picture of the overall look and size began to emerge. We found fossils that ranged from quite small, just a foot or two, to well over twenty-six metres in length and resembled both modern fish and dolphins. This specimen holds a well-deserved spot of honour on Liam's mantle. The detail is tremendous and just look at that masterful prep work.

PLESIOSAURS OF THE YORKSHIRE COAST

These two lovely Plesiosaur vertebrae were found by Liam Langley on fossil field trips to the Yorkshire Coast on the east coast of England.

Plesiosaurus was a large, carnivorous air-breathing marine reptile with strong jaws and sharp teeth that moved through the water with four flippers. We'd originally thought that this might not be the most aerodynamic design but it was clearly effective as they used the extra set to create a wee vortex that aided in their propulsion. In terms of mechanical design, they have a little something in common with dragonflies.

We've recreated plesiosaur movements and discovered that they were able to optimize propulsion to make use of their own wake. As their front flippers paddled in big circular movements, the propelled water created little whirlpools under their bellies.

The back flippers would then paddle between these whirlpools pushing the plesiosaur forward to maximal effect. They were very successful hunters, outcompeting ichthyosaurs who thrived in the Triassic but were replaced in the Jurassic and Cretaceous by these new aquatic beasties. Our ancient seas teemed with these predatory marine reptiles with their long necks and barrel-shaped bodies. Plesiosaurs were smaller than their pliosaur cousins, weighing in at about 450 kg or 1,000 lbs and reaching about 4.5 metres or 15 feet in length. For a modern comparison, they were roughly twice as long as a standard horse or about as long as a good size hippo.

Plesiosaurs first appeared in the latest Triassic, during the Rhaetian. They thrived in the Jurassic and vanished at the end of the Cretaceous in time with the K-Pg extinction event along with a host of other species. They are one of the marine reptiles that we associate with the infamous Mary Anning, a paleo darling of the early 19th century who found her first fossil specimen in the winter of 1823. These two vertebrae grace the home of the talented Mr. Langley. Anning's plesiosaur can be viewed in London's Natural History Museum.

SHONISAURUS OF NEVADA

The beauties you see here are ichthyosaurs. The largest of their lineage is the genus Shonisaurus who ruled our ancient seas 217 million years ago.

At least 37 incomplete fossil specimens of the marine reptile have been found in hard limestone deposits of the Luning Formation, in far northwestern Nye County of Nevada. This formation dates to the late Carnian age of the late Triassic period when present-day Nevada and parts of the western United States were covered by an ancient ocean.

The first researcher to recognize the Nevada fossil specimens as ichthyosaurs was Siemon W. Muller of Stanford University. He had the work of Sir Richard Owen and others to build on. That being said, there are very few contenders for a species that boasts vertebrae over a foot wide and weighing in at almost 10 kg or 21 lbs. Muller contacted the University of California Museum of Paleontology at Berkeley. Surface collecting by locals continued at the site but no major excavation was planned.

Sir Richard Owen, the British biologist, comparative anatomist and paleontologist, coined the name ichthyopterygia, or "fish flippers," one hundred and fourteen years earlier, but that wee bit of scientific knowledge hadn't made its way west to the general population. The finds at Luning were still, "marine monsters."

Owen, too, was building on research going back to 1699, the very first recorded fossil fragments found of these beasties in Wales. Shortly thereafter, fossil vertebrae were published in 1708 from the Lower Jurassic.

The first complete skeleton was discovered in the early 19th century by Mary Anning and her brother Joseph along the Dorset Jurassic Coast. Mary's find was described by a British surgeon, Sir Everard Home, an elected Fellow of the Royal Society, in 1814. The specimen is now on display at the Natural History Museum in London bearing the name Temnodontosaurus platyodon, or “cutting-tooth lizard.”

In 1821, William Conybeare and Henry De La Beche, a friend of Mary's, published a paper describing three new species of unknown marine reptiles based on the Anning's finds. The Rev. William Buckland would go on to describe two small ichthyosaurs from the Lias of Lyme Regis, Ichthyosaurus communis and Ichthyosaurus intermedius. All of this early work was instrumental in aiding the researchers who would join the project at Luning.

Owen is considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. Contrary to common belief, advanced study does help with identifying fossils, but what is truly needed is a keen eye. The finds at Luning were blessed to be seen by an enthusiastic local with just that right kind of keen eye.

Almost a quarter of a century after Muller's initial reports, Dr. Charles L. Camp from UCMP received correspondence further detailing the finds from a lovely Mrs. Margaret Wheat of Fallon. She wrote to Camp in September of 1928 to say that she'd been giving the quarry section a bit of a sweep, as you do, and had uncovered a nice aligned section of vertebrae with her broom. The following year, Dr. Charles L. Camp went out to survey the finds and began working on the specimens, his first field season of many, in 1954.

Back in the 1950s, these large marine reptiles were rumoured to be "marine monsters," as the concept of an ichthyosaur was not well understood by the local townsfolk. Excitement soon hit West Union Canyon as the quarry began to reveal the sheer size of these mighty beasts. Four of the specimens were fully excavated. Most of the ichthyosaur bones were left in situ, partially because the work was tremendously difficult, and partially to allow others to see how the specimens were laid down over 200 million years ago.

Camp continued to work with Wheat at the site and brought on Sam Welles and a host of students to help with excavations. The team understood the need for protection at the site. They canvassed the Nevada Legislature to establish the Ichthyosaur Paleontological State Monument. You can see one of the Park Rangers above giving a tour within the lovely Fossil Hut building they built on the site to protect the fossils.

In 1957, the site was incorporated into the State Park System and Berlin-Ichthyosaur State Park was born. The park Twenty years later, in 1977, the population of Nevada weighed in and the Legislature designated Shonisaurus popularis as the State Fossil of Nevada. Visitors are welcome to collect fossils from the exposures of the Upper Triassic (Early Norian, Kerri Zone) of the Luning Formation, West Union Canyon, just outside Berlin-Ichthyosaur State Park.

Address: State route 844, Austin, NV 89310, United States. Area: 4.58 km². Open 24 hours;
Elevation: 6,975 ft (2,126 m); Tel: +1 775-964-2440; http://parks.nv.gov/parks/berlin-ichthyosaur

THEROPODS OF A FEATHER

Birds are a group of warm-blooded vertebrates constituting the class Aves, characterized by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton.

These modern dinosaurs live worldwide and range in size from the 5 cm (2 in) bee hummingbird to the 2.75 m (9 ft) ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds.

Birds have wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds.

Wings, which evolved from forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming.

Best of all, birds are feathered theropod dinosaurs, and constitute the only living dinosaurs. Based on fossil and biological evidence, most scientists accept that birds are a specialized subgroup of theropod dinosaurs, and more specifically, they are members of Maniraptora, a group of theropods which includes dromaeosaurs and oviraptorids, amongst others. As palaeontologists discover more theropods closely related to birds, the previously clear distinction between non-birds and birds has become a bit muddy.

Recent discoveries in the Liaoning Province of northeast China, which include many small theropod feathered dinosaurs — and some excellent fakes — contribute to this ambiguity. Still, other fossil specimens found here shed a light on the evolution of Aves. Confuciusornis sanctus, an Early Cretaceous bird from the Yixian and Jiufotang Formations of China is the oldest known bird to have a beak.

Like modern birds, Confuciusornis had a toothless beak, but close relatives of modern birds such as Hesperornis and Ichthyornis were toothed, telling us that the loss of teeth occurred convergently in Confuciusornis and living birds.

Confuciusornis sanctus, Cretaceous Bird from China, 125 mya

The consensus view in contemporary palaeontology is that the flying theropods, or avialans, are the closest relatives of the deinonychosaurs, which include dromaeosaurids and troodontids.

Together, these form a group called Paraves. Some basal members of this group, such as Microraptor, have features which may have enabled them to glide or fly. The most basal deinonychosaurs were wee little things. This evidence raises the possibility that the ancestor of all paravians may have been arboreal, have been able to glide, or both. Unlike Archaeopteryx and the non-avialan feathered dinosaurs, who primarily ate meat, tummy contents from recent avialan studies suggest that the first avialans were omnivores. Even more intriguing...

Avialae or "bird wings" are a clade of flying dinosaurs containing the only living dinosaurs, the birds. It is usually defined as all theropod dinosaurs more closely related to modern birds (Aves) than to deinonychosaurs, though alternative definitions are occasionally bantered back and forth.

Archaeopteryx lithographica, from the late Jurassic Period Solnhofen Formation of Germany, is the earliest known avialan which may have had the capability of powered flight. However, several older avialans are known from the Late Jurassic Tiaojishan Formation of China, dating to about 160 million years ago.

The Late Jurassic Archaeopteryx is well-known as one of the first transitional fossils to be found, and it provided support for the theory of evolution in the late 19th century. Archaeopteryx was the first fossil to clearly display both traditional reptilian characteristics — teeth, clawed fingers, and a long, lizard-like tail—as well as wings with flight feathers similar to those of modern birds. It is not considered a direct ancestor of birds, though it is possibly closely related to the true ancestor.

Unlikely yet true, the closest living relatives of birds are the crocodilians. Birds are descendants of the primitive avialans — whose members include Archaeopteryx — which first appeared about 160 million years ago in China.

DNA evidence tells us that modern birds — Neornithes — evolved in the Middle to Late Cretaceous, and diversified dramatically around the time of the Cretaceous–Paleogene extinction event 66 mya, which killed off the pterosaurs and all non-avian dinosaurs.

In birds, the brain, especially the telencephalon, is remarkably developed, both in relative volume and complexity. Unlike most early‐branching sauropsids, the adults of birds and other archosaurs have a well‐ossified neurocranium. In contrast to most of their reptilian relatives, but similar to what we see in mammals, bird brains fit closely to the endocranial cavity so that major external features are reflected in the endocasts. What you see on the inside is what you see on the outside.

This makes birds an excellent group for palaeoneurological investigations. The first observation of the brain in a long‐extinct bird was made in the first quarter of the 19th century. However, it was not until the 2000s and the application of modern imaging technologies that avian palaeoneurology really took off.

Understanding how the mode of life is reflected in the external morphology of the brains of birds is but one of several future directions in which avian palaeoneurological research may extend.

Although the number of fossil specimens suitable for palaeoneurological explorations is considerably smaller in birds than in mammals and will very likely remain so, the coming years will certainly witness a momentous strengthening of this rapidly growing field of research at the overlap between ornithology, palaeontology, evolutionary biology and the neurosciences.

Reference: Cau, Andrea; Brougham, Tom; Naish, Darren (2015). "The phylogenetic affinities of the bizarre Late Cretaceous Romanian theropod Balaur bondoc (Dinosauria, Maniraptora): Dromaeosaurid or flightless bird?". PeerJ. 3: e1032. doi:10.7717/peerj.1032. PMC 4476167. PMID 26157616.

Reference: Ivanov, M., Hrdlickova, S. & Gregorova, R. (2001) The Complete Encyclopedia of Fossils. Rebo Publishers, Netherlands. p. 312

Photo: By Tommy from Arad - Confuciusornis; FunkMonk, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=24115307

ANEMONEFISH NURSERY

Anemonefish colonies usually consist of the reproductive male and female and a few male juveniles, which help tend the colony.

Although multiple males cohabit an environment with a single female, polygamy does not occur and only the adult pair exhibits reproductive behaviour. If the female dies, the social hierarchy shifts with the breeding male exhibiting protandrous sex reversal to become the breeding female.

The largest juvenile then becomes the new breeding male after a period of rapid growth. The existence of protandry in anemonefish may rest on the case that nonbreeders modulate their phenotype in a way that causes breeders to tolerate them. This strategy prevents conflict by reducing competition between males for one female. For example, by purposefully modifying their growth rate to remain small and submissive, the juveniles in a colony present no threat to the fitness of the adult male, thereby protecting themselves from being evicted by the dominant fish.

The reproductive cycle of anemonefish is often correlated with the lunar cycle. Rates of spawning for anemonefish peak around the first and third quarters of the moon. The timing of this spawn means that the eggs hatch around the full moon or new moon periods. One explanation for this lunar clock is that spring tides produce the highest tides during full or new moons. Nocturnal hatching during high tide may reduce predation by allowing for a greater capacity for escape. Namely, the stronger currents and greater water volume during high tide protect the hatchlings by effectively sweeping them to safety. Before spawning, anemonefish exhibit increased rates of anemone and substrate biting, which help prepare and clean the nest for the spawn.

In terms of parental care, male anemonefish are often the caretakers of eggs. Before making the clutch, the parents often clear an oval-shaped clutch varying in diameter for the spawn. Fecundity, or reproductive rate, of the females, usually ranges from 600 to 1500 eggs depending on her size. In contrast to most animal species, the female-only occasionally takes responsibility for the eggs, with males expending most of the time and effort. Male anemonefish care for their eggs by fanning and guarding them for 6 to 10 days until they hatch. In general, eggs develop more rapidly in a clutch when males fan properly, and fanning represents a crucial mechanism of successfully developing eggs.

This suggests that males can control the success of hatching an egg clutch by investing different amounts of time and energy towards the eggs. For example, a male could choose to fan less in times of scarcity or fan more in times of abundance. Furthermore, males display increased alertness when guarding more valuable broods, or eggs in which paternity was guaranteed. Females, though, display generally less preference for parental behavior than males. All these suggest that males have increased parental investment towards the eggs compared to females.

SEA ANEMONE NURSERY

Sea anemones are familiar inhabitants of rocky shores and coral reefs around the world; other species can be found at very low depths indeed. Most of the soft-bodied anthozoans known as "sea anemones" are classified in the Actinaria.

Most actinarians are sessile; that is, they live attached to rocks or other substrates and do not move, or move only very slowly by contractions of the pedal disk. A number of anemones burrow into sand, and a few can even swim short distances, by bending the column back and forth or by "flapping" their tentacles. In all, there are about 1000 species of sea anemone in the world's oceans.

Sea anemones breed by liberating sperm and eggs through their mouth into the sea. The fertilized eggs develop into planula larvae which, after being planktonic for a while, settle on the seabed and develop directly into juvenile polyps. Sea anemones can also breed asexually, by breaking in half or into smaller pieces which regenerate into polyps.

They are sometimes kept in reef aquariums; the global trade in marine ornamentals is expanding and threatens sea anemone populations in some localities, as the trade depends on collection from the wild. Most Actiniaria do not form hard parts that can be recognized as fossils, but a few fossils of sea anemones do exist; Mackenzia, from the Stephen Formation, Middle Cambrian Burgess Shale of Canada, is the oldest fossil identified as a sea anemone.

Some fossil sea anemones have also been found from the Lower Cambrian of China. The new find lends support to genetic data that suggests anthozoans — anemones, corals, octocorals and their kin — were one the first Cnidarian groups to diversify.

Reference:  Conway Morris, S. (1993). "Ediacaran-like fossils in Cambrian Burgess Shale–type faunas of North America". Palaeontology. 36 (31–0239): 593–635.

SEA ANEMONES: MARINE PREDATORS

Sea Anenome on Coral Reef

Sea anemones are a group of predatory marine animals in the order Actiniaria. They are named after the anemone, a terrestrial flowering plant because of the colourful appearance of so many of these lovelies.

Sea anemones are in the phylum Cnidaria, class Anthozoa, subclass Hexacorallia. As cnidarians, sea anemones are related to corals, jellyfish, tube-dwelling anemones, and Hydra.

Unlike jellyfish, sea anemones do not have a medusa stage in their life cycle. A typical sea anemone is a single polyp attached to a hard surface by its base, but some species live in soft sediment and a few float near the surface of the water. The polyp has a columnar trunk topped by an oral disc with a ring of tentacles and a central mouth.

The tentacles can be retracted inside the body cavity or expanded to catch passing prey. They are armed with cnidocytes (stinging cells). In many species, additional nourishment comes from a symbiotic relationship with single-celled dinoflagellates, zooxanthellae or with green algae, zoochlorellae, that live within the cells. Some species of sea anemone live in association with hermit crabs, small fish or other animals to their mutual benefit.