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.

SEXUAL DIMORPHISM

Despite the differences between these two ammonites, both represent the same species, Macroscaphites yvani. The difference you see here is caused by sexual dimorphism. The larger of these is the female macroconch and the smaller specimen is the male of the species. These beauties are in the collection of the deeply awesome José Juárez Ruiz.

NOTOCHORDS AND SPINAL COLUMNS

Having a backbone or spinal column is what sets apart you, me and almost 70,000 species on this big blue planet.

So which lucky ducks evolved one? Well, ducks for one. Warm-blooded birds and mammals cheerfully claim those bragging rights. They're joined by our cold-blooded, ectothermic friends, the fish, amphibians and reptiles. All these diverse lovelies share this characteristic.

And whether they now live at sea or on land, all of these lineages evolved from a marine organism somewhere down the line, then went on to develop a notochord and spinal column. Notochords are flexible rods that run down the length of chordates and vertebrates. They are handy adaptations for muscle attachment, helping with signalling and coordinating the development of the embryonic stage. The cells from the notochord play a key role in the development of the central nervous system and the formation of motor neurons and sensory cells. Alas, we often take our evolution for granted.

Let's take a moment to appreciate just how marvellous this evolutionary gift is and what it allows us to do. Your backbone gives your body structure, holds up that heavy skull of yours and connects your tasty brain to your body and organs. Eating, walking, fishing, hunting, your morning yoga class, are all made possible because of this adaptation. Pick pretty near anything you love to do and it is only possible because of your blessed spine. And it sets us apart from our invertebrate friends.

Arturia nautiloid, Olympic Peninsula

While seventy thousand may seem like a large number, it represents less than three to five percent of all described animal species. The rest is made up of the whopping 97%'ers, our dear invertebrates who include the arthropods (insects, arachnids, crustaceans, and myriapods), mollusks (our dear chitons, snails, bivalves, squid, and octopus), annelids (the often misunderstood earthworms and leeches), and cnidarians (our beautiful hydras, jellyfish, sea anemones, and corals).

You'll notice that many of our invertebrate friends occur as tasty snacks. Having a backbone provides a supreme advantage to your placement in the food chain. Not always, as you may include fish and game on your menu. But generally, having a backbone means you're more likely to be holding the menu versus being listed as an appetizer. So, enjoy your Sunday 'downward dog' and thank your backbone for the magical gift it is.

AUSTRALOPITHECUS AFRICANUS

Two views of a natural endocranial cast articulated with a fragmentary skull of Australopithecus africanus, an early hominid living between 2-3 million years ago in the late Pliocene and into the early Pleistocene -- and the first pre-human to be discovered. They shared many characteristics with their older relatives the Australopithecus afarensis including a more gracile body. The casts you see here show the left maxilla, the orbital area and most of the skull base.

Australopithecus africanus had a larger brain and more humanoid facial features than their older ancestors with an average endocranial volume of 485 cm3 (29.6 cu in). This specimen is TM 1511 and lives in the Ditsong National Museum of Natural History, an amalgamation of eight museums, seven in Tshwane and one in Johannesburg. These museums have diverse collections covering the fields of fauna and flora, palaeontology, military history, cultural history, geology, anthropology and archaeology. The museum is enjoyed by children, youth, adults, students, tourists (foreign and local), researchers and the public in general. The museum is in Pretoria, South Africa which straddles the Apies River and has spread eastwards into the foothills of the Magaliesberg mountains.

Prior to a closer look by researchers, the skull was incorrectly believed to be a separate species, Plesianthropus transvaalensis. It was first discovered in South Africa by G. W. Barlow and described by Robert Broom in 1938. Photo credit: José Braga and Didier Descouens.

CADOCERAS OF HARRISON LAKE

Cadoceras (Paracadoceras) tonniense

This lovely ammonite is Cadoceras (Paracadoceras) tonniense (Imlay, 1953), a fast-moving nektonic carnivore from the Jurassic macrocephalites macrocephalus ammonoid zone of the Mysterious Creek Formation near Harrison Lake in British Columbia. These specimens were found on the first paleontological field trip of 2020 by Vancouver Paleontological Society Vice-Chair, John Fam. They were rediscovering a few of the old GSC localities north of the main collecting outcrops.

These rare beauties are from the Lower Callovian, 164.7 - 161.2 million years ago. Interestingly, the ammonites from here are quite similar to the ones found within the lower part of the Chinitna Formation, Alaska and Jurassic Point, Kyuquot, on the west coast of Vancouver Island.

These species are from Callomon's (1984) Cadoceras comma Fauna B8 for the western Cordillera of North America, which is equivalent in part to the Macrocephalus Zone of Europe of the Early Callovian. The faunal association at locality 17 near Harrison suggests a more precise correlation to Callomon's zonation; namely, the Cadoceras wosnessenskii Fauna B8(e) found in the Chinitna Formation, southern Alaska (Imlay, 1953b). The type specimen is USNM 108088, from locality USGS Mesozoic 21340, Iniskin Peninsula, found in a Callovian marine siliciclastic in the Chinitna Formation of Alaska.

There are many fossils to be found on the west side of the Harrison lake near the town of Harrison, British Columbia. Exploration of the geology around Harrison Lake has a long history with geologists from the Geological Survey of Canada studying geology and paleontological exposures as far back as the 1880s. They were probably looking for coal exposures —  but happy day, they found fossils!

The paleo outcrops were first mentioned in the Geological Survey of Canada's Director's Report in 1888 (Selwyn, 1888), then studied by Whiteaves a year later. Whiteaves identified the prolific bivalve Aucella (now Buchia) from several specimens collected in 1882 by A. Bowman of the Geological Survey of Canada. The first detailed geological work in the Harrison Lake area was undertaken in a doctoral study by Crickmay (1925), who compiled a geological map, describing the stratigraphy and establishing the formational names, many of which we still use today. Crickmay went on to interpret the paleogeography and structure of the region. There was a time in the early 2000s, when Jim Haggart asked one of the VanPS members to take up the mantle and try to cherry-pick through a boatload of buchia finds to sort their nomenclature. I'm not sure if that project ever bore fruit.

Cadoceras (Paracadoceras) tonniense

Around Harrison Lake, Callovian beds of the Mysterious Creek Formation are locally overlain disconformably by 3,000 feet of Early Oxfordian conglomerate. We find Cadoceras tonniense here and at nine localities in the Alaska Peninsula and Cook Inlet regions of the USA.

If you'd like to visit the site at Chinitna Bay, you'll want to hike into 59.9° N, 153.0° W: paleo-coordinates 31.6° N, 86.6° W.

If you're a keen bean for the Canadian site, you can drive the 30 km up Forestry Road #17, stopping just past Hale Creek at 49.5° N, 121.9° W: paleo-coordinates 42.5° N, 63.4° W, on the west side of Harrison Lake. You'll see Long Island to your right. If you can pre-load the Google Earth map of the area you'll thank yourself. Pro tip: access Forestry Road #17 at the northeast end of the parking lot from the Sasquatch Inn at 46001 Lougheed Hwy, Harrison  Mills. Look for signs for the Chehalis River Fish Hatchery to get you started. NTS: 92H/05NW; 92H/05SW; 92H/12NW; 92H/12SW.

A. J. Arthur, P. L. Smith, J. W. H. Monger and H. W. Tipper. 1993. Mesozoic stratigraphy and Jurassic paleontology west of Harrison Lake, southwestern British Columbia. Geological Survey of Canada Bulletin 441:1-62

R. W. Imlay. 1953. Callovian (Jurassic) ammonites from the United States and Alaska Part 2. The Alaska Peninsula and Cook Inlet regions. United States Geological Survey Professional Paper 249-B:41-108

An overview of the tectonic history of the southern Coast Mountains, British Columbia; Monger, J W H; in, Field trips to Harrison Lake and Vancouver Island, British Columbia; Haggart, J W (ed.); Smith, P L (ed.). Canadian Paleontology Conference, Field Trip Guidebook 16, 2011 p. 1-11 (ESS Cont.# 20110248).

Photos: These photos are from the first paleontological field trip of 2020 by Vancouver Paleontological Society Vice-Chair, John Fam.

OUT OF AFRICA

The geology of South Africa is highly varied including cratons, greenstone belts, large impact craters as well as orogenic belts. The geology of the country is the base for a large mining sector that extracts gold, diamonds, iron and coal from world-class deposits.

The geomorphology of South Africa consists of a high plateau rimmed to west, south and southeast by the Great Escarpment and rugged mountains beyond this there is a strip of narrow coastal plain. The basement of much of the northeastern part of South Africa is made up of the Kaapvaal Craton. To the south and east, the craton is bordered by the Namaqua-Natal belt.

In Neoproterozoic times, much of South Africa stabilized into the large Kalahari Craton that came to form part of the supercontinent Rodinia. The Kalahari Craton was near the center of Rodinia with paleogeographic reconstructions indicating it was surrounded by the cratons of Laurentia, Río de la Plata, Congo and Dronning Maud Land. Evidence of this is the continuation of the Namaqua-Natal belt in East Antarctica indicating that South Africa and East Antarctica formed a single continent when this belt formed about 1000 million years ago.

Since the Mesozoic, the tectonics of South Africa has been shaped by an initial phase of rifting and then by episodic epeirogenic movements. South Africa is currently an elevated passive margin much like Eastern Greenland and the Brazilian Highlands.

The uplift of these margins is tentatively related to far-field compressional stresses that have warped the region as a giant anticline-like lithosphere fold. These tectonics have had a profound effect in shaping the Great Escarpment and uplifting, creating and destroying plateaux including the African Surface, a key reference surface.

On average, 2.5 to 3.5 km rock was eroded in the Mid to Late Cretaceous. Further erosion in Cenozoic times amounts to less than one kilometre. Limited erosion means that many of the major relief features of South Africa have existed since the Late Cretaceous. Warping of Southern Africa has led to significant changes in drainage basins with the Orange River likely losing a drainage area in the Kalahari Basin, the Limpopo River losing interior drainage areas to the Zambezi River and the west-draining Karoo River ceasing to exist altogether. Overall, the boundaries of the drainage basins coincide with the axes of uplifted epeirogenic flexures.

MAMMOTH LAST MEAL

One of the first scientific accounts of a well-preserved woolly mammoth (Mammuthus primigenius) frozen in Siberia described the meat as enticingly red and marbled but smelling so putrid that researchers could only tolerate a minute in its proximity.

Despite this initial review, numerous apocryphal tales exist of dinners made from centuries-old mammoths found frozen whole in clear blocks of ice. These accounts have not only enchanted the public but also heavily influenced early scientific thought on Quaternary extinctions and climate; many researchers resorting to catastrophism to explain the instantaneous freezing necessary to preserve palatable meat.

The possibility of cloning is now the major draw of frozen mammoths but the public remains curious about eating prehistoric meat, especially because some modern paleontologists have credibly described tasting mammoth and extinct bison found preserved in permafrost.

Although less publicized today, eating study specimens was once common practice for researchers. Charles Darwin belonged to a club dedicated to tasting exotic meats, and in his first book wrote almost three times as much about dishes like armadillo and tortoise urine than he did on the biogeography of his Galapagos finches.

One of the most famously strange scientific meals occurred on January 13, 1951, at the 47th Explorers Club Annual Dinner (ECAD) when members purportedly dined on frozen woolly mammoth. The prehistoric meat was supposedly found on Akutan Island in Alaska, USA, by the eminent polar explorers Father Bernard Rosecrans Hubbard, “the Glacier Priest,” and Captain George Francis Kosco of the US Navy.

This much-publicized meal captured the public’s imagination and became an enduring legend and source of pride for the Club, popularizing an annual menu of “exotics” that continues today, making the Club as well-known for its notorious hors d’oeuvres like fried tarantulas and goat eyeballs as it is for its notable members such as Teddy Roosevelt and Neil Armstrong.

The Yale Peabody Museum holds a sample of meat preserved from the 1951 meal, interestingly labelled as a South American Giant Ground Sloth, Megatherium, not Mammoth.

Green Sea Turtle, Chelonia mydas

The specimen of meat from that famous meal was originally designated BRCM 16925 before a transfer in 2001 from the Bruce Museum to the Yale Peabody Museum of Natural History (New Haven, CT, USA) where it gained the number YPM MAM 14399.

The specimen is now permanently deposited in the Yale Peabody Museum with the designation YPM HERR 19475 and is accessible to outside researchers. The meat was never fixed in formalin and was initially stored in isopropyl alcohol before being transferred to ethanol when it arrived at the Peabody Museum. DNA extraction occurred at Yale University in a clean room with equipment reserved exclusively for aDNA analyses.

In 2016, Jessica Glass and her colleagues sequenced a fragment of the mitochondrial cytochrome-b gene and studied archival material to verify its identity, which if genuine, would extend the range of Megatherium over 600% and alter views on ground sloth evolution. Their results showed that the meat was not Mammoth or Megatherium, but a bit of Green Sea Turtle, Chelonia mydas. So much for elaborate legends. The prehistoric dinner was likely meant as a publicity stunt. Glass's study emphasizes the value of museums collecting and curating voucher specimens, particularly those used for evidence of extraordinary claims. Not so long before Glass et al. did their experiment, a friend's mother (and my kayaking partners) served up a steak from her freezer to dinner guests in Castlegar that hailed from 1978. Tough? Inedible? I have it on good report that the meat was surprisingly divine.

Reference: Glass, J. R., Davis, M., Walsh, T. J., Sargis, E. J., & Caccone, A. (2016). Was Frozen Mammoth or Giant Ground Sloth Served for Dinner at The Explorers Club?. PloS one, 11(2), e0146825. https://doi.org/10.1371/journal.pone.0146825

SUNSHINE AND SUPERNOVAE

Sunsets — pure visual poetry: peaceful, meditative, mesmerizing.

What is sunlight, actually? Yes, it's light from the Sun but so much more than that. Sunlight is both light and energy. Once it reaches Earth, we call this energy, "insolation," a fancy term for solar radiation. The amount of energy the Sun gives off changes over time in a never-ending cycle.

Solar flares (hotter) and sunspots (cooler) on the Sun's surface impact the amount of radiation headed to Earth. These periods of extra heat or extra cold (well, cold by Sun standards...) can last for weeks, sometimes months. The beams that reach us and warm our skin are electromagnetic waves that bring with them heat and radiation, by-products of the nuclear fusion happening as hydrogen nuclei fuse and shift violently to form helium, a process that fires every star in the sky.

Our bodies convert the ultraviolet rays to Vitamin D. Plants use the rays for photosynthesis, a process of converting carbon dioxide to sugar and using it to power their growth (and clean our atmosphere!) That process looks something like this: carbon dioxide + water + light energy — and glucose + oxygen = 6 CO2(g) + 6 H2O + photons → C6H12O6(aq) + 6 O2(g).

Photosynthetic organisms convert about 100–115 thousand million metric tonnes of carbon to biomass each year, about six times more power than used us mighty homo sapien sapiens. Our plants, forests and algae soak up this goodness and much later in time, we harvest this energy from fossil fuels.

We've yet to truly get a handle on the duality between light as waves and light as photons. The duality of the two-in-oneness of light; of their waves and alter-ego, particle photons is a physicists delight. Einstein formulated his special theory of relativity in part by thinking about what it would be like to ride around on these waves. What would space look and feel like? How would time occur? It bends the mind to consider. His wave-particle view helped us to understand that these seemingly different forms change when measured. To put this in plain English, they change when viewed, ie. you look them "in the eye" and they behave as you see them.

Light fills not just our wee bit of the Universe but the cosmos as well, bathing it in the form of cosmic background radiation that is the signature of the Big Bang and the many mini-big bangs of supernovae as they go through cycles of reincarnation and cataclysmic death — exploding outward and shining brighter than a billion stars.

In our solar system, once those electromagnetic waves leave the Sun headed for Earth, they reach us in a surprising eight minutes. We experience them as light mixed with the prism of beautiful colours. But what we see is actually a trick of the light. As rays of white sunlight travel through the atmosphere they collide with airborne particles and water droplets causing the rays to scatter.

We see mostly the yellow, orange and red hues (the longer wavelengths) as the blues and greens (the shorter wavelengths) scatter more easily and get bounced out of the game rather early.

HOLDERNESS AMMONITE

An unusual Yorkshire Holderness ammonite about 5cm across found by Harry Tabiner. He’s found a few of these specimens preserved completely with calcite making them hard to prepare. It’s possibly Kosmoceras, a middle Jurassic ammonite.

The Geology of Yorkshire in northern England shows a very close relationship between the major topographical areas and the geological period in which their rocks were formed. The rocks of the Pennine chain of hills in the west are of Carboniferous origin whilst those of the central vale are Permo-Triassic.

The North York Moors in the north-east of the county are Jurassic in age while the Yorkshire Wolds to the southeast are Cretaceous chalk uplands. The plain of Holderness and the Humberhead levels both owe their present form to the Quaternary ice ages. The strata become gradually younger from west to east. Much of Yorkshire presents heavily glaciated scenery as few places escaped the direct or indirect impact of the great ice sheets as they first advanced and then retreated during the last ice age. This beauty is in the collection of the deeply awesome Harry Tabiner.

CORAL: CLIMATE CHANGE INDICATORS

A lovely specimen of fossilized coral. Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically live in compact colonies of many identical individual polyps.

Annual growth bands in some corals, such as the deep-sea bamboo coral, Isididae, may be among the first signs of the effects of ocean acidification on marine life. The growth rings allow geologists to construct year-by-year chronologies, a form of incremental dating, which underlies high-resolution records of past climatic and environmental changes using geochemical techniques.

Certain species form communities called microatolls, which are colonies whose top is dead and mostly above the waterline, but whose perimeter is mostly submerged and alive. The average tide level limits their height. By analyzing the various growth morphologies, microatolls offer a low-resolution record of sea-level change. Fossilized microatolls can also be dated using Radiocarbon dating. Such methods can help to reconstruct Holocene sea levels.

Increasing sea temperatures in tropical regions, ~1 degree C, over the last century have caused major coral bleaching, death, and collapsing of coral populations since although they are able to adapt and acclimate. It is uncertain if this evolutionary process will happen quickly enough to prevent a major reduction of their numbers.

Though coral has large sexually-reproducing populations, their evolution can be slowed by abundant asexual reproduction. Gene flow is variable among coral species. According to the biogeography of coral species gene flow cannot be counted on as a dependable source of adaptation as they are very stationary organisms. Also, coral longevity might factor into their adaptivity.

However, adaptation to climate change has been demonstrated in many cases. These are usually due to a shift in coral and zooxanthellae genotypes. These shifts in allele frequency have progressed toward more tolerant types of zooxanthellae. Scientists found that a certain scleractinian zooxanthella is becoming more common where sea temperature is high. Symbionts able to tolerate warmer water seem to photosynthesize more slowly, implying an evolutionary trade-off.

In the Gulf of Mexico, where sea temperatures are rising, cold-sensitive staghorn and elkhorn coral have shifted in location. Not only have the symbionts and specific species been shown to shift, but there seems to be a certain growth rate favorable to selection. Slower-growing but more heat-tolerant corals have become more common. The changes in temperature and acclimation are complex. Some reefs in current shadows represent a refugium location that will help them adjust to the disparity in the environment even if eventually the temperatures may rise more quickly there than in other locations. This separation of populations by climatic barriers causes a realized niche to shrink greatly in comparison to the old fundamental niche.

CORAL COLONIES

Coral colony and Soldier Fish, Great Barrier Reef, Australia

Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically live in compact colonies of many identical individual polyps.

Corals are important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.

A coral "group" is a colony of a myriad of genetically identical polyps. Each polyp is a sac-like animal typically only a few millimetres in diameter and a few centimetres in length. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form planulae, a mobile early form of the coral polyp which when mature settles to form a new colony.

Although some corals are able to catch plankton and small fish using stinging cells on their tentacles, most corals obtain the majority of their energy and nutrients from photosynthetic unicellular dinoflagellates of the genus Symbiodinium that live within their tissues. These are commonly known as zooxanthellae and gives the coral colour. Such corals require sunlight and grow in clear, shallow water, typically at depths less than 60 metres (200 ft). Corals are major contributors to the physical structure of the coral reefs that develop in tropical and subtropical waters, such as the Great Barrier Reef off the coast of Australia. These corals are increasingly at risk of bleaching events where polyps expel the zooxanthellae in response to stress such as high water temperature or toxins.

Other corals do not rely on zooxanthellae and can live globally in much deeper water, such as the cold-water genus Lophelia which can survive as deep as 3,300 metres (10,800 ft). Some have been found as far north as the Darwin Mounds, northwest of Cape Wrath, Scotland, and others off the coast of Washington State and the Aleutian Islands.

TUZOIA OF THE BALANG FORMATION

A large extinct bivalved arthropod, Tuzoia sinesis (Pan, 1957) from Cambrian deposits of the Balang Formation. The Balang outcrops in beautiful Paiwu, northwestern Hunan Province in southern China. The site is intermediate in age between the Lower Cambrian Chengjiang fauna of Yunnan and the Lower to Middle Cambrian, Kaili Lagerstätten of Guizhou in southwestern China.

This specimen was collected in October 2019. It is one of many new and exciting arthropods to come from the site. Balang has a low diversity of trilobites and many soft-bodied fossils similar in preservation to Canada's Burgess Shale.

Some of the most interesting finds include the first discovery of anomalocaridid appendages (Appendage-F-type) from China along with the early arthropod Leanchoiliids with his atypical frontal appendages (and questionable phylogenetic placement) and the soft-shelled trilobite-like arthropod, Naraoiidae.

Jianheaspis jiaobangensis, is a newly described trilobite also from the Lower Cambrian Balang Formation of Guizhou Province, China. While the site is not as well-studied as the Chengjiang and Kaili Lagerstätten, it looks very promising. The exceptionally well-preserved fauna includes algae, sponges, chancelloriids, cnidarians, worms, molluscs, brachiopods, trilobites and a few non-mineralized arthropods. It is an exciting time for Cambrian paleontology. The Balang provides an intriguing new window into our ancient seas and the profound diversification of life that flourished there.

ZEACINITIES MAGNOLIAEFORMIS

This lovely specimen is Zeacrinites magnoliaeformis, an Upper Mississippian-Chesterian crinoid found by Keith Metts in the Glen Dean Formation, Grayson County, Kentucky, USA.

Crinoids are unusually beautiful and graceful members of the phylum Echinodermata. They resemble an underwater flower swaying in an ocean current. But make no mistake they are marine animals. Picture a flower with a mouth on the top surface that is surrounded by feeding arms. Awkwardly, add an anus right beside that mouth. That's him!

Crinoids with root-like anchors are called Sea Lilies. They have graceful stalks that grip the ocean floor. Those in deeper water have longish stalks up to 3.3 ft or a meter in length.

Then there are other varieties that are free-swimming with only vestigial stalks. They make up the majority of this group and are commonly known as feather stars or comatulids. Unlike the sea lilies, the feather stars can move about on tiny hook-like structures called cirri. It is these same cirri that allows crinoids to latch to surfaces on the seafloor. Like other echinoderms, crinoids have pentaradial symmetry. The aboral surface of the body is studded with plates of calcium carbonate, forming an endoskeleton similar to that in starfish and sea urchins.

These make the calyx somewhat cup-shaped, and there are few, if any, ossicles in the oral (upper) surface called a tegmen. It is divided into five ambulacral areas, including a deep groove from which the tube feet project, and five interambulacral areas between them. The anus, unusually for echinoderms, is found on the same surface as the mouth, at the edge of the tegmen.

Crinoids are alive and well today. They are also some of the oldest fossils on the planet. We have lovely fossil specimens dating back to the Ordovician.

PHYLLOCERAS PONTICULI DE CORDOBA

Phylloceras (Hypophylloceras) ponticuli from the Subbético Externo de Córdoba, a fast-moving carnivorous ammonite. This classical Tethyan Mediterranean specimen is very well preserved, showing much of his delicate suturing in intricate detail. Phylloceras were primitive ammonites with involute, laterally flattened shells.

They were smooth, with very little ornamentation, which led researchers to think of them resembling plant leaves and gave rise to their name, which means leaf-horn. They can be found in three regions that I know of.  In the Jurassic of Italy near western Sicily's Rosso Ammonitico Formation, Lower Kimmeridgian fossiliferous beds of Monte Inici East and Castello Inici (38.0° N, 12.9° E: 26.7° N, 15.4° E) and in the Arimine area, southeastern Toyama Prefecture, northern central Japan, roughly, 36.5° N, 137.5° E: 43.6° N, 140.6° E. And in Madagascar, in the example seen here found near Sokoja, Madagascar, off the southeast coast of Africa at 22.8° S, 44.4° E: 28.5° S, 18.2° E. Photo: Manuel Peña Nieto

PHYLLOCERAS VELLEDAE

This specimen of Phylloceras velledae (Michelin) has a shell with a small umbilicus, arched, acute venter, and at some growth stage, falcoid ribs that spring in pairs from umbilical tubercles, disappearing on the outer whorls.

This specimen has been polished to show the sutures to great effect. These ammonites are common in rock shops and plentiful on the internet.

These ammonites make a lovely addition to any teaching collection as they provide a lot of detail and can be handled quite well by small, less gentle hands. Like other cephalopods, ammonites had sharp, beak-like jaws inside a ring of squid-like tentacles that extended from their shells. They used these tentacles to snare prey, — plankton, vegetation, fish and crustaceans — similar to the way a squid or octopus hunt today.

Catching a fish with your hands is no easy feat, as I'm sure you know. But the Ammonites were skilled and successful hunters. They caught their prey while swimming and floating in the water column. Within their shells, they had a number of chambers, called septa, filled with gas or fluid that were interconnected by a wee air tube. By pushing air in or out, they were able to control their buoyancy in the water column.

They lived in the last chamber of their shells, continuously building new shell material as they grew. As each new chamber was added, the squid-like body of the ammonite would move down to occupy the final outside chamber.

They were a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids — octopuses, squid, and cuttlefish) than they are to shelled nautiloids such as the living Nautilus species.

LENS ON SEPTARIAN NODULES

Septarian Nodule, Dan Bowen, 2020 Tucson Gem and Mineral Show

An exceptional polished septarian nodule with an ammonite heart. Septarian concretions or septarian nodules are concretions containing angular cavities or cracks, called "septaria." These septaria can be filled 

The word comes from the Latin word septum; "partition", and refers to the cracks/separations in this kind of rock.

The process that created the septaria that characterize septarian concretions remains unclear. A number of mechanisms have been proposed, including the dehydration of clay-rich, gel-rich, or organic-rich cores; shrinkage of the concretion's center; expansion of gases produced by the decay of organic matter; or brittle fracturing or shrinkage of the concretion interior by either earthquakes or compaction.

The cracks or patterns you see here are highly variable in shape and volume, as well as the degree of shrinkage they indicate. Although it has commonly been assumed that concretions grew incrementally from the inside outwards, the fact that radially oriented cracks taper towards the margins of septarian concretions is taken as evidence that in these cases the periphery was stiffer while the inside was softer, presumably due to a gradient in the amount of cement precipitated.

A spectacular example of septarian concretions, which are as much as 3 meters (9.8 feet) in diameter, are the Moeraki Boulders. These concretions are found eroding out of Paleocene mudstone of the Moeraki Formation exposed along the coast near Moeraki, South Island, New Zealand. They are composed of calcite-cemented mud with septarian veins of calcite and rare late-stage quartz and ferrous dolomite.

Beautiful smaller septarian concretions are found in the Kimmeridge Clay exposed in cliffs along the Wessex Coast of England. As as you walk the beach, look for exposures of Speeton Clay beds D6 and D7, the bentonite horizons that weather to yellow colouration. Beneath the Speeton Shell Bed cliff exposures is an exposure of Kimmeridge Clay, UK. This outcrop contains concretions that show the characteristic 'turtle-stone' patterns of these septarian nodules.

Photo top: Dan Bowen, Chair, VIPS, 2020 Tucson Gem and Mineral Show.

References: Humberside Geologist No. 14, Humberside Geologist Online, The geology of East Yorkshire coast.http://www.hullgeolsoc.co.uk/hg146t.htm

Dale, P.; Landis, C. A.; Boles, J. R. (1985-05-01). "The Moeraki Boulders; anatomy of some septarian concretions". Journal of Sedimentary Research. 55 (3): 398–406.

Milliken, Kitty L.; Picard, M. Dane; McBride, Earle F. (2003-05-01). "Calcite-Cemented Concretions in Cretaceous Sandstone, Wyoming and Utah, U.S.A." Journal of Sedimentary Research. 73 (3): 462–483. Bibcode:2003JSedR..73..462M. doi:10.1306/111602730462. ISSN 1527-1404.

AMMONITES: INDEX FOSSILS

Ammonites were prolific breeders that evolved rapidly. If you could cast a fishing line into our ancient seas, it is likely that you would hook an ammonite, not a fish. They were prolific back in the day, living (and sometimes dying) in schools in oceans around the globe.

We find their fossilized remains (and plenty of them) in sedimentary rock from all over the world. In some cases, we find rock beds where we can see evidence of a new species that evolved, lived and died out in such a short time span that we can walk through time, following the course of evolution using ammonites as a window into the past. For this reason, they make excellent index fossils.

An index fossil is a species that allows us to link a particular rock formation, layered in time with a particular species or genus found there. Generally, deeper is older, so we use the sedimentary layers rock to match up to specific geologic time periods, rather the way we use tree-rings to date trees. Photo: Dan Bowen, 2020 Tucson Gem and Mineral Show.

HOLCOPHYLLOCERAS MEDITERRANEUM

There is tremendously robust suturing on this lovely ammonite, Holcophylloceras mediterraneum, (Neumayr 1871) from Late Jurassic (Oxfordian) deposits near Sokoja, Madagasgar.

They were a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids — octopuses, squid, and cuttlefish) than they are to shelled nautiloids such as the living Nautilus species.

Ammonites first appeared about 240 million years ago, though they descended from straight-shelled cephalopods called bacrites that date back to the Devonian, about 415 million years ago, and the last species vanished in the Cretaceous–Paleogene extinction event.

The shells had many chambers divided by walls called septa. The chambers were connected by a tube called a siphuncle which allowed for the control of buoyancy with the hollow inner chambers of the shell acting as air tanks to help them float. We can see the edges of this specimen's shell where it would have continued out to the last chamber, the body chamber, where the ammonite lived. Picture a squid or octopus, now add a shell and a ton of water.

ANDROGYNOCERAS OF YORKSHIRE

A stunning example of the ammonite Androgynoceras from the Yorkshire Coast, England.

The Geology of Yorkshire in northern England shows a very close relationship between the major topographical areas and the geological period in which their rocks were formed. The rocks of the Pennine chain of hills in the west are of Carboniferous origin whilst those of the central vale is Permo-Triassic.

The North York Moors in the north-east of the county are Jurassic in age while the Yorkshire Wolds to the southeast are Cretaceous chalk uplands.

The plain of Holderness and the Humberhead levels both owe their present form to the Quaternary ice ages. The strata become gradually younger from west to east. Much of Yorkshire presents heavily glaciated scenery as few places escaped the direct or indirect impact of the great ice sheets as they first advanced and then retreated during the last ice age. This beauty is in the collection of the deeply awesome Harry Tabiner.

MIDDLE TRIASSIC HUMBOLDT RANGE

Looking out over the Middle Triassic exposures of the Humboldt Mountain Range.

These hills were the site of the 1905 Expedition of the University of California’s Department of Geology in Berkeley funded by the beautiful and bold, Annie Alexander, the women to whom the UCMP owes both its collection and existence. Annie brought together a paleontological crew to explore these localities and kept an expedition journal of their trip which is now on display at the University of California Museum of Paleontology at Berkeley.

Annie's interest was the ichthyosaurs and she was well pleased with the results. They dodged rattlesnakes and tarantulas, finding many new specimens as they opened up new quarries in the hills of the Humboldt Range of Nevada.

Ichthyosaurs range from quite small, just a foot or two, to well over twenty-six metres in length and resembled both modern fish and dolphins. The specimens from Nevada are especially large and well-preserved. They hail from a time, some 217 million years ago, when Nevada, and parts of the western USA, was covered by an ancient ocean that would one day become our Pacific Ocean. Many ichthyosaur specimens have come out of Nevada. So many, in fact, that they named it their State Fossil back in 1977.

Fossil fragments and complete specimens of these marine reptiles have been collected in the Blue Lias near Lyme Regis and the Black Ven Marls. More recently, specimens have been collected from the higher succession near Seatown. Paddy Howe, Lyme Regis Museum geologist, found a rather nice Ichthyosaurus breviceps skull a few years back. A landslip in 2008 unveiled some ribs poking out of the Church cliffs and a bit of digging revealed the ninth fossil skull ever found of a breviceps, with teeth and paddles to boot.

Specimens have since been found in Europe in Belgium, England, Germany, Switzerland and in Indonesia. Many tremendously well-preserved specimens come from the limestone quarries in Holzmaden, southern Germany.

AMMONITE: INDEX FOSSILS

Ammonites first appeared about 240 million years ago, though they descended from straight-shelled cephalopods called bacrites that date back to the Devonian, about 415 million years ago, and the last species vanished in the Cretaceous–Paleogene extinction event.

They were prolific breeders that evolved rapidly. If you could cast a fishing line into our ancient seas, it is likely that you would hook an ammonite, not a fish. They were prolific back in the day, living — and sometimes dying — in schools in oceans around the globe. We find ammonite fossils — and plenty of them — in sedimentary rock from all over the world. In some cases, we find rock beds where we can see evidence of a new species that evolved, lived and died out in such a short time span that we can walk through time, following the course of evolution using ammonites as a window into the past.

For this reason, they make excellent index fossils. An index fossil is a species that allows us to link a particular rock formation, layered in time with a particular species or genus found there. Generally, deeper is older, so we use the sedimentary layers rock to match up to specific geologic time periods, rather the way we use tree-rings to date trees. A handy way to compare fossils and date strata across the globe.

UPPER CRETACEOUS NANAIMO GROUP AT HORNBY ISLAND

Hornby is a delightful island off the east coast of Vancouver Island, just east of Denman Island. Texada and Lasqueti lie just to the west of Hornby. It is home to about 1,000 residents made up of artists, retirees and those wanting to enjoy the quiet, rural, community-oriented lifestyle.

Hornby Island is formed from sediments of the upper Nanaimo Group which are also widely exposed on adjacent Denman Island and the southern Gulf Islands. Peter Mustard, a geologist from the Geologic Survey of Canada, did considerable work on the geology of the island. It has a total stratigraphic thickness of 1350 m of upper Nanaimo Group marine sandstone, conglomerate and shale.

These are partially exposed in the Campanian to the lower Maastrichtian outcrops at Collishaw Point on the northwest side of Hornby Island. Four formations underlie the island from oldest to youngest, and from west to east: the Northumberland, Geoffrey, Spray and Gabriola.

During the upper Cretaceous, between ~90 to 65 Ma, sediments derived from the Coast Belt to the east and the Cascades to the southeast poured seaward to the west and northwest into what was the large ancestral Georgia Basin. This major forearc basin was situated between Vancouver Island and the mainland of British Columbia.

The island's soils have developed from marine deposits of variable texture, except for the higher elevations and steeper slopes where weathered clastic sedimentary rock provides the parent material. Most of Hornby's soils are sandy or gravelly, but some deep black loams occur in the northwestern part and many of the sands at the southern end have loam-textured topsoils.

Collishaw Point, known locally as Boulder Point, Hornby Island

Podzols are common and the bleached sand grains associated with their eluvial (A2, Ae or E) horizons lend a salt-and-pepper appearance to many forest trails. In most cases, though, the E is not very thick and may, in fact, be discontinuous. For this reason, the soils were mostly classified as Brown Podzolic in a soil survey published in 1959.

All of the island's soils are strongly acidic in their natural state except for those which have developed on shoreline shell middens.

And it is to the shore that many are drawn — locals, tourists, geologists and paleontologists alike. Hornby is a wonderful place to explore. 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.

The Nanaimo Group as a whole represents largely coarse-grained units deposited in deep-sea fan systems. In this environment, deeper channels continuously cut through successive shale and sandstone bodies. The channels funnelled density currents into the basin, while also building levee deposits. Turbidity currents travelled down the channels, and also overtopped the levees spilling across backslope areas. The sequential sediment formations, from significantly coarse-grained sandstones and conglomerates to fine silts and shale units of the Nanaimo Group, are considered to be partly due to eustacy, but more significantly related to relative sea-level changes induced by regional tectonics in an active forearc setting.

The Northumberland Formation consists of a massive, dark-grey mudstone which is locally interlaminated and interbedded with siltstone and fine-grained sandstone.

There are abundant calcium carbonate concretions, parallel and current ripple laminations, clastic dikes and folded layers due to slumping. In the Gulf Islands to the south, this formation has been found to contain abundant and diverse foraminifera indicating marine paleodepths of 150-1200 m.

The more resistive Geoffrey Formation consists of thick-bedded sandstone and conglomerate. It is highly channelized, and some sandstone has exposed parallel and ripple laminations. The Spray Fm exposed on the east end of the island is a massive olive-grey mudstone with interlaminations of sandstone.

Furthest to the east, the youngest exposures on Hornby Island are from the Gabriola Formation, which outcrops on the eastern peninsula. This is again a thick-bedded and channelized sequence of conglomerates and massive sandstone with minor mudstone interbeds. South, in the Gulf Islands, this formation has contained ammonites, gastropods and pelecypods. Paleowater-depth from foraminiferal assemblages has been set at 200 m.

Katnick, D.C. and P.S. Mustard (2001): Geology of Denman and Hornby Islands, British Columbia (NTS 92F/7E, 10); British Columbia Geological Survey Branch, Geoscience Map 2001-3.

England, T.D.J. and R. N. Hiscott (1991): Upper Nanaimo Group and younger strata, outer Gulf Islands, southwestern British Columbia: in Current Research, Part E; Geological Survey of Canada, Paper 91-1E, p. 117-125.

LIVING FOSSIL: HEDGEHOGS

This little cutie is a Western European hedgehog, Erinaceus europaus, in the subfamily Erinaceinae (Fischer, 1814). They are native to western Europe, Asia, Africa and have been introduced (oops!) to New Zealand.

There are seventeen species of hedgehog in five genera. They share distant ancestry with the family Soricidae (shrews) and the gymnures.

Hedgehogs are considered "Living Fossils" as they have changed very little over the past 15 million years. These small mammals are loners with their own kind but live in close proximity to our human population. They dwell in inhabited areas, farmland, deciduous forests and desert. You'll know them by their distinctive spiny look (which may remind you of very tasty chocolates from Purdy's in Canada) and their adorable piglike snorts and grunts as they make their way through the underbrush looking for tasty snacks.

Look for them in the evening in hedgerows and undergrowth as they hunt for frogs, toads, snails, bird eggs, grassroots, berries, insects, worms and snakes. They fatten themselves up in preparation for hibernation. They'll find a nice burrow or built a nest in leaves or compost heaps. In Europe, they generally hibernate by October or November and become active again in March to mid-April once temperatures reach over 15 degrees.

JURASSIC STILL LIFE

This beautiful block, an ancient Still Life of the Jurassic (Callovian) hails from outcrops near Anwil, a municipality in the district of Sissach in the canton of Basel-Country in Switzerland.

It is a tremendous block showing the fauna from that time. Ammonites and Trigonia are clustered together. This specimen was found and prepared by the talented Tim Haye. Tim made the find during his inspection of a 2014 excavation through the Bern and Basel Museums.

PALEONTOLOGIE FRANCAISE

Paléontologie Française: Alcide d'Orbigny

L'un des grands classiques, Paléontologie Française: Zoologique Et Géologique de Tous les Animaux Mollusques Et Rayonnés Fossiles de France, Comprenant Leur Application A la Reconnaissance des Couches; Terrains Crétacés, Supplément. Voici une citation de cette édition:

"Eepl. Des fig. Pl. 4, fig. 4, cône alvéolaire de grandeur naturelle, vu de profil; a la tige: la partie ombrée est ce qu'on connaît en nature, le reste est supposé fig.

Le même, vu en dessus; fig. 3, godet terminal, supposé d'après les lignes d'accroissement; fig. 4, coquille entière, supposée d'après les lignes d'accroissement marquées sur le cône alvéolaire; fig. 5, la figure 2 grossie, la partie non ombrée supposée; fig. 6, la figure grossie; et, partie supposée; b, partie positive; fig. 7, cône alvéolai're vu en dessus, avec son siphon ventre, de ma collection."

PRIMITIVE PTERASPIDOMORPHS

The oldest and most primitive pteraspidomorphs were the Astraspida and the Arandaspida.

They evolved in shallow equatorial seas, as a large diverse and widespread group of armoured, jawless fishes: the Pteraspidomorphi. The first of three groups of ostracoderms.

The Pteraspidomorphi are divided into three major groups: the Astraspida, Arandaspida and the Heterostraci. You'll notice that their taxon names contain 'aspid', which means shield. This is because these early fishes and many of the Pteraspidomorphi possessed large plates of dermal bone at the anterior end of their bodies. This dermal armour was very common in early vertebrates, but it was lost in their descendants.

Arandaspida is represented by two well-known genera: Sacabampaspis, from South America and Arandaspis from Australia. Arandaspis have large, simple, dorsal and ventral head shields. Their bodies were fusiform, which means they were shaped sort of like a spindle, fat in the middle and tapering at both ends. Picture a sausage that is a bit wider near the centre with a crisp outer shell.

Photo by Nobu Tamura (http://spinops.blogspot.com) - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19460450

JUVENILE HAMITES SUBROTUNDUS

A tremendously delicate juvenile Hamites subrotundus (J. Sowerby 1814) from Upper Albian outcrops in Mallorca, the largest of the Spanish Balearic Island in the Mediterranean. It is famous for its limestone mountains and Roman and Moorish remains. As you can see here, it is also home to some rather nice fossils including this specimen of Hamites subrotundus.

While H. subrotundus is generally a Middle Albian species, this specimen was found in the lower part of Upper Albian in the Cristatum zone by José Juárez Ruiz. José had to piece this lovely together from seven fragments. His labour of love was worth the effort. The final piece is sheer perfection and a beautiful specimen approximately 2.5 cm long.

Mallorca and the other Balearic Islands are geologically an extension of the Betic Cordillera of Andalusia. They are made up of sediments deposited in the Tethys Sea during the Mesozoic.

Exploring the islands, you can collect from deposits from the Triassic, Cretaceous, Jurassic, and Neogene periods. The limestone outcrops contain many foraminifers of the species Globigerina.

We also see lovely examples of Hamites (Hamites) subrotundus in the Euhoplites loricatus zone; Euhoplites meandrinus subzone from the Middle Albian (Lower Gault) of Folkestone, Kent, UK. Photo, preparation and in the collection of the deeply awesome José Juárez Ruiz. Wright C. W. 1996. Treatise on Invertebrate Paleontology (Part L Mollusca 4 Revised) Volume 4: Cretaceous Ammonoidea

GRAPTOLITES: DARLINGS OF THE DARRIWILIAN

Back in 2009, Jörg Maletz from St. Francis Xavier University, Antigonish, Nova Scotia, did a paper looking at the Les Méchins region in Quebec to compare the Darriwilian graptolite succession found there against other outcrops of eastern North America.

The graptolite faunas of the upper member of the Anse au Crapaud Formation include the Arienigraptus gracilis, Oncograptus upsilon, Undulograptus austrodentatus, and Holmograptus spinosus biozone faunas and, thus, complement the well known Darriwilian faunas of the Cow Head, Table Head, and Goose Tickle groups of western Newfoundland. In particular, the Holmograptus spinosus Biozone interval of calcarenitic limestones bears a rare combination of benthic (shelly) and planktic (graptolitic) faunas with conodonts, brachiopods, ostracods, sponge spicules, and algal remains associated with common graptolites that allow an inter-continental correlation.

The Holmograptus spinosus Biozone is introduced for the interval based on a diverse and characteristic graptolite fauna. The fauna includes among others, Atopograptus woodwardi, recognized for the first time in North America. The Holmograptus spinosus Biozone fauna can be found worldwide and is easily correlated into the conodont biofacies using species of the genus Histiodella. He looked at ties between graptolite and conodont biozonations for the Darriwilian. Some lovely silicified ostracods were illustrated for the first time from the interval and a new species, Hustedograptus quebecensis, was introduced.

The Darriwilian or late Middle Ordovician time interval shows a dramatic re-organization of graptolite faunas, both in their taxonomic composition and in their rhabdosome developmental style.

The Early Ordovician graptolite faunas, composed of multiramous to pauciramous “Dichograptaceans” (Bulman 1970), are slowly replaced by dipleural biserial graptolites of the “Diplograptaceans” (Mitchell et al. 1995, 2007) or Axonophorans (Maletz et al. 2009).

This shift started with the introduction of the reclined isograptids and glossograptids in the Dapingian and culminated with the extinction of multiramous sinograptids and stem reclinatids in the Darriwilian (Da 2 – Da 3), leaving but few survivors to reach the Late Ordovician. The monopleural glossograptids, as a second clade of the Bireclinata, enjoyed moderate success in the mid and Late Ordovician, but never attained the high diversity of the Axonophorans.

The Darling Darriwilian

The Darriwilian is a significant stage in the Middle Ordovician. It is here we see the first land plants and the introduction of the Undulograptus austrodentatus graptolite zone. These graptolite outcrops from around the world help us establish the base of the Darriwilian as an easily correlatable marker in time. Yet, for so many reasons, the charming Darriwilian has not received the attention in graptolite studies it deserves and little is known about many of the graptolites from the interval.

The biostratigraphy within this time interval remains only partially explored due to a scarcity of uninterrupted successions. The Darriwilian in Victoria, Australia (Vandenberg and Cooper 1992) is based on numerous spot collections, but successions spanning more than a single graptolite zone are not available. The base of the Darriwilian is now defined at the first appearance datum (FAD) of Undulograptus austrodentatus in the Huangnitang section (Zhejiang, China), but the graptolitic succession is less detailed and complete in the higher part of the interval (see Chen et al. 2006).

The northern Appalachian successions in Quebec and western Newfoundland provide numerous successions from which detailed biostratigraphical data are available, but most sections are poorly studied. Recent advances show the presence of good Darriwilian graptolite faunas in the Cow Head, Table Head, and Goose Tickle groups of western Newfoundland (Williams and Stevens 1988; Maletz 1992c; Taylor 1997) and China (Chen et al. 2006) that provide a better insight into the biostratigraphy and evolutionary history of graptolites in this interval.

Lithostratigraphic Succession at Les Méchins

The southern shore of the St. Lawrence River along the coast of the Gaspé Peninsula of Quebec exposes Cambrian to Ordovician continental slope sequences, representing the allochthonous thrust slices of the Humber tectonostratigraphic zone of Williams (1979). The successions were thrust westwards across the eastern rim of Laurentia during the Taconic Orogeny in the Middle Ordovician. Because of the complexity of the successions, the stratigraphy is only well defined in part and detailed biostratigraphic work is lacking for most regions.

Bernstein et al. (1992) described the lithostratigraphic succession at Les Méchins and provided detailed information on the location of the sections along the northern side of route 132, directly west of the entrance to Les Méchins.

As graptolites are the most important biostratigraphic indicators, their record can shed light on the structural complexity of the successions and help us to understand the geological evolution of this region. Newly discovered faunal successions at Les Méchins, Quebec have provided important biostratigraphical and biogeographical data and yielded taxa not previously found in North America.

Maletz, Jörg. Holmograptus spinosus and the Middle Ordovician (Darriwilian) graptolite biostratigraphy at Les Méchins (Quebec, Canada) Canadian Journal of Earth Sciences, 2009, 46:739-755, https://doi.org/10.1139/E09-048.

Albanesi, G., Hünicken, M.A., and Barnes, C.R. 1998. Bioestratigrafia de conodontes de las secuencias ordovicicas del Cerro Potrerillo, Precordillera central de San Juan, R. Argentina. Actas XII Academia Nacional de Ciencias., Córdoba, 12, pp. 7–72.

Bulman, O.M.B. 1970. Graptolithina with sections on Enteropneusta and Pterobranchia. In Treatise on invertebrate paleontology, Part V. 2nd ed. Edited by K. Teichert and R.C. Moore. Geological Society of America and University of Kansas Press, Boulder, Colo. and Lawrence, Kans., pp. 1–163.

Chen X, Zhang YD, Bergström SM, Xu H-G. 2006. Darriwilian graptolite and conodont zonation in the global stratotype section of the Darriwilian stage (Ordovician) at Huangnitang, Changshan, Zhejiang, China. Palaeoworld 15(2): 150-170.

ARIENIGRAPTUS OF BOLIVIA

Graptolites (Graptolita) are a group of colonial animals known primarily from Ordovician deposits. The biological affinities of the graptolites have always been debatable.

Originally regarded as being related to the hydrozoans, graptolites are now considered to be related to the pterobranchs, a rare group of modern marine animals.

The graptolites are classed as hemichordates (phylum Hemichordata), a phylum of marine deuterostome animals and come in a variety of weird and wonderful designs. They were a major component of the zooplankton in our early Paleozoic ecosystems, most likely living as suspension feeders, drifting freely on the surface of ancient seas or attached to floating seaweed by means of a slender thread. Some forms of graptolite lived attached to the sea-floor by a root-like base. The deceased planktonic graptolites would sink down to and settle on the seafloor, eventually becoming entombed in the sediment and are thus well-preserved.

Graptolite fossils are often found in shales and slates and can be mistaken for scratches on the rock. The name graptolite comes from the Greek graptos meaning "written", and lithos meaning "rock." It is a very suitable name as many graptolites look very much like hieroglyphs written on rock and not the impressions of animals.

Graptolites are common fossils and have a worldwide distribution. The preservation, quantity and gradual change over a geologic time scale of graptolites allow the fossils to be used to date strata of rocks throughout the world. They are important index fossils for dating Palaeozoic rocks as they evolved rapidly with time and formed many different species.

We find graptolite fossils flattened along the bedding planes of the rocks in which they occur. My first graptolite finds were from roadcuts up near Cranbrook, British Columbia, Canada. I was on a fossil field trip looking for Cambrian trilobites. It was a thrilling experience and completely unexpected when the first graptolite met my eyes.

They vary in shape, but are most commonly dendritic or branching (such as Dictoyonema), saw-blade like, or "tuning fork" shaped, such as Didymograptus murchisoni. The lovely specimen of Arienigraptus sp. you see here is from the Lower Darriwilian of Bolivia and in the collections of the deeply awesome Gilberto Juárez Huarachi‎. The second photo is from the Encyclopaedia Brittanica - From the Encyclopaedia Brittanica, Public Domain, https://commons.wikimedia.org/w/index.php?curid=6886878

PERSISTISTROMBUS LATUS

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.

Persististrombus latus 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.