CALAMOPLEURUS OF BRAZIL

This well-preserved fossil fish skull is from Calamopleurus (Agassiz, 1841), an extinct genus of bony fishes related to the heavily armoured ray-finned gars.

They are fossil relics, the sole surviving species of the order Amiiformes. Although bowfins are highly evolved, they are often referred to as primitive fishes and living fossils as they retain many of the morphologic characteristics of their ancestors.

This specimen was found in Lower Cretaceous outcrops of the Santana Formation in the Araripe Basin UNESCO Global Geopark. The Santana Formation of north-east Brazil contains one of the most important Mesozoic fossil Konservat Lagerstatten on Gondwana (Maisey, 1991; Martill, 1993, 1997, 2001; Kellner, 2002; Fara et al., 2005). The formation crops out on the flanks of the Chapada do Araripe in southern Ceara´, western Pernambuco and a small part of eastern Piaui in the north-eastern Brazilian Caatinga. It forms part of a heterogeneous assemblage of spectacularly fossiliferous rocks of Cretaceous age (Gardner, 1841; Brito, 1984; Maisey, 1991; Martill, 1993).

Two formations within the basin are well-known as Konservat Lagerstatten; the Nova Olinda Member of the Crato Formation lies a few tens of metres below the Santana Formation, and both have contributed considerably to our knowledge and understanding of Gondwanan Cretaceous palaeobiotas (Martill, 1988, 1993; Wenz and Brito, 1990; Maisey, 1991, 1993; and many references herein). Only the age of the Romualdo Member of the Santana Formation, a dominantly silty shale sequence that includes the highly fossiliferous carbonate concretion-bearing unit, is considered here.

Although the Santana Formation concretions have been famous for their enclosed fossils, especially fishes, for over 150 years, in more recent times they have become known for a diversity of dinosaur and pterosaur remains in an excellent state of preservation (Martill, 1998; Martill and Unwin, 1989; Kellner, 1996a,b; Frey et al., 2003a,b) comparable with, and sometimes exceeding, that of the Jurassic Solnhofen Limestone of Bavaria (Barthel et al., 1990), especially in their three-dimensionality. Photo and collection of David Murphy.

References: Martill, David M. The age of the Cretaceous Santana Formation fossil Konservat Lagerstatten of north-east Brazil: a historical review and an appraisal of the biochronostratigraphic utility of its palaeobiota, Cretaceous Research 28 (2007) 895-920.

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

SALTRIO THEROPOD

In the summer of 1996, Angelo Zanella, an avocational fossil collector and active collaborator at the Museo di Storia Naturale di Milano (MSNM) spotted some intriguing fossil bone sticking out of a large block of rock while hunting for ammonites in the Salnova marble quarry.

The quarry is in the Alpine foothills, at the Swiss–Italian border near Saltrio. Saltrio is about 80 km north of Milan in the province of Varese, Lombardy, Italy.

Zanella reported the bones to the MSNM, which arranged a paleontological expedition to the site. The research was difficult because the explosives used for industrial quarrying had blown up the fossil-bearing layer and had broken it into hundreds of pieces.

The Saltrio quarry has been active since the 15th century as one of the finest sites of marble production, and the “Saltrio Stone” provides high-quality building materials for many famous Italian monuments  — the Scala Opera House in Milan and the Mole Antonelliana in Turin. They actively use dynamite to extract the marble. Great for the workers who are not required to manually break-up the massive pieces. Less so for the fossils. The bones from the Saltrio theropod were blown to bits just prior to Zanella's discovery then had to be pieced back together.

Three years later, after 1,800 h of chemical preparation in the Laboratory of the MSNM, 132 remains were extracted from three main blocks. Although fragmentary, jaw fragments, one tooth, rib remains, pectoral and limb bones were analyzed and found to be that of a large theropod dinosaur.

The Saltrio theropod (MSNM V3664) became popular by the name, Saltriosauro, and so it was reported (Dal Sasso, 2001a) and preliminarily described (Dal Sasso, 2001b, 2004).

Pictured above: selected elements used in the diagnosis of Saltriovenator zanellai n. gen. n. sp. Right humerus in medial (A), frontal (B) and distal (C) views; (D) left scapula, medial view; (E) right scapular glenoid and coracoid, lateral view; (F) furcula, ventral view; tooth, labial (G) and apical (H) views; (I) left humerus, medial view; right second metacarpal in dorsal (J), lateral (L) and distal (N) views; first phalanx of the right second digit in dorsal (K), lateral (M) and proximal (O) views; (P–T) right third digit in proximal, dorsal and lateral views; (U) right distal tarsal IV, proximal view; third right metatarsal in proximal (V) and frontal (X) views; second right metatarsal, proximal (W) and frontal (Y) views; (Z) reconstructed skeleton showing identified elements (red). Abbreviations as in text, asterisks mark autapomorphic traits. Scale bars: 10 cm in (A)–(E), (I), and (U)–(Y); two cm in (F), and (J)–(T); one cm in (G).

Photos by G. Bindellini, C. Dal Sasso and M. Zilioli; drawing by M. Auditore. - https://peerj.com/articles/5976/

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.

CLOWN FISH: SYMBIOSIS

The colourful wee fellows you see here are Clown Fish. They have an unusual relationship with sea anemones. Clownfish or anemonefish are fishes from the subfamily Amphiprioninae in the family Pomacentridae. Thirty species are recognized: one in the genus Premnas, while the remaining are in the genus Amphiprion.

In the wild, they all form symbiotic mutualisms with sea anemones, each providing benefits to the other.

The individual species are generally highly host-specific, and especially the genera Heteractis and Stichodactyla, and the species Entacmaea quadricolor are frequent anemonefish partners.

The sea anemone protects the anemonefish from predators, as well as providing food through the scraps left from the anemone's meals and occasional dead anemone tentacles, and functions as a safe nest site. In return, the anemonefish defends the anemone from its predators and parasites.

The anemone also picks up nutrients from the anemonefish's excrement. The nitrogen excreted from anemonefish increases the number of algae incorporated into the tissue of their hosts, which aids the anemone in tissue growth and regeneration.

The activity of the anemonefish results in greater water circulation around the sea anemone, and it has been suggested that their bright colouring might lure small fish to the anemone, which then catches them. Studies on anemonefish have found that they alter the flow of water around sea anemone tentacles by certain behaviours and movements such as "wedging" and "switching". Aeration of the host anemone tentacles allows for benefits to the metabolism of both partners, mainly by increasing anemone body size and both anemonefish and anemone respiration.

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.

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