MAASTRICHTIAN CLUPEIFORMES

A stunning example of the Late Cretaceous fish, Gasteroclupea branisai, from Bolivia. This beauty is housed in the Natural History Museum Alcide d'Orbignay of Cochabamba.

Gasteroclupea is a genus of prehistoric clupeiform fish related to modern anchovies and herrings.

Clupeiformes are physostomes, which means that the gas bladder has a pneumatic duct connecting it to the gut. This handy little evolutionary feature lets them fill or empty the gas bladder via their mouth. They typically lack lateral lines but have nicely defined eyes, fins and scales. They are generally silvery fish with streamlined, spindle-shaped, bodies, and often found in schools. Most species eat plankton which they filter from the water with their gills.

Gasteroclupea date back to the Maastrichtian of the Late Cretaceous. We find fossils of the genus in the Yacoraite Formation of Argentina and in the El Molino Formation of Bolivia, as you see here. Photo credit: Gilberto Juárez Huarachi‎.

PHEASANT PHASIANUS

These playful lovelies are beautiful examples of the Common Pheasant, Phasianus Cholchicus.

We associate them with tweet shorn English aristocrats jauntily going about the hunt on horseback. 

Pheasants build their nests on the ground and can fly for short distances. They spend their days searching the scrub in fields and around streams looking for tasty insects, seeds and grain.

ARMOURED AGNATHA

This lovely specimen, showing both the positive and negative of the fossil, is an armoured agnatha jawless bony fish, Victoraspis longicornualis, from Lower Devonian deposits of Podolia, Ukraine.

Victoraspis longicornualis was named by Anders Carlsson and Henning Bloom back in 2008. The new osteostracan genus and species were described based on material from Rakovets' present-day Ukraine. This new taxon shares characteristics with the two genera Stensiopelta (Denison, 1951) and Zychaspis (Javier, 1985).

Agnatha is a superclass of vertebrates. This fellow looks quite different from our modern Agnatha, which includes lamprey and hagfish. Ironically, hagfish are vertebrates that do not have vertebrae. Sometime in their evolution, they lost them as they adapted to their environment. Photo: Fossilero Fisherman

TRIASSIC AMMONOIDS

CANGREJO FÓSIL: COSTACOPLUMA

Cuticular structure in a Late Maastrichtian crab, Costacopluma mexicana, from deposits near the town of from near Paredón, Ramos Arizpe in what is now southern Coahuila (formerly Coahuila de Zaragoza), north-eastern Mexico. We see this same species in the Upper Cretaceous Moyenne of Northeast Morocco and from the Pacific slope, Paleocene of California, USA. This beauty is in the collection of José F. Ventura‎.

While the crustacean cuticle has been the subject of study for over 250 years (Reaumur, 1712, in Drach, 1939), the focus of that early work has been the process of moulting. Because crabs and other crustaceans have a hard outer shell (the exoskeleton) that does not grow, they must shed their shells through a process called moulting. Just as we outgrow our shoes, crabs outgrow their shells.

In 1984, Roer and Dillaman took a whole new approach, instead looking at the exoskeleton as a mineralized tissue. The integument of decapod crustaceans consists of an outer epicuticle, an exocuticle, an endocuticle and an inner membranous layer underlain by the hypodermis. The outer three layers of the cuticle are calcified.

The mineral is in the form of calcite crystals and amorphous calcium carbonate. In the epicuticle, the mineral is in the form of spherulitic calcite islands surrounded by the lipid-protein matrix. In the exo- and endo-cuticles the calcite crystal aggregates are interspersed with chitin-protein fibres which are organized in lamellae. In some species, the organization of the mineral mirrors that of the organic fibres, but such is not the case in certain cuticular regions in the xanthid crabs.

Control of crystal organization is a complex phenomenon unrelated to the gross morphology of the matrix. Since the cuticle is periodically moulted to allow for growth, this necessitates a bidirectional movement of calcium into the cuticle during post-moult and out during premolt resorption of the cuticle.

These movements are accomplished by active transport affected by a Ca-ATPase and Na/Ca exchange mechanism. The epi- and exo-cuticular layers of the new cuticle are elaborated during pre-moult but do not calcify until the old cuticle is shed. This phenomenon also occurs in vitro in the cuticle devoid of living tissue and implies an alteration of the nucleating sites of the cuticle in the course of the moult.

We're still learning about the relationship between the mineral and the organic components of the cuticle, both regarding the determination of crystal morphology and about nucleation. While the Portunidae offers some knowledge of the mechanisms and pathways for calcium movement, we know nothing concerning the transport of carbonate. These latter areas of investigation will prove fertile ground for future work; work which will provide information not only on the physiology of Crustacea but also on the basic principles of mineralization. I'm interested to see what insights will be revealed in the years to come. Certainly, the bidirectional nature of mineral transport and the sharp temporal transitions in the nucleating ability of the cuticular matrix provide ideal systems in which to study these aspects of calcification.

Torrey Nyborg, Francisco J. Vega and Harry F. Filkorn, Boletín de la Sociedad Geológica Mexicana, Vol. 61, No. 2, Número especial XI Congreso Nacional de Paleontología, Juriquilla 2009 (2009), pp. 203-209. Coahuila paleo coordinates:25°32′26″N 100°57′2″W

BIBONIDAE: LATE BLOOMING POLLINATORS

A recent post of the fossils found at McAbee in the Interior of British Columbia has me thinking of March Flies. March Flies are hardy, medium-sized flies in the Order Diptera, with a body length ranging from 4.0 to 10.0 mm. They tend to make for excellent specimens as they fossilize rather well. This species is one of the most satisfying fossils to collect in the Eocene deposits of McAbee and in the outskirts of Princeton, British Columbia.

The body is black, brown, or rusty, and thickset, with thick legs. The antennae are moniliform. The front tibiae bear large strong spurs or a circlet of spines. The tarsi are five-segmented and bear tarsal claws, pulvilli, and a well-developed empodium. As it is with many species, these guys included, the teens of this species are troublesome but the adults turn out alright. As larvae, Bibionidae is an agricultural pest, devouring all those tasty young seedlings you've just planted.

Then, as they mature their tastes turn to the nectar of flowers from fruit trees and la voila, they become your best friends again. With their physical and behavioural transformation complete, Bibionidae becomes a welcome garden visitor, pulling their weight in the ecosystems they live in by being important pollinators.

AMMONITE CLUSTER

Ammonites have intricate and complex patterns on their shells called sutures. The suture patterns differ across species and tell us what time period the ammonite is from. 

Ammonoidea can be divided into six orders:

Agoniatitida: Lower Devonian - Middle Devonian

Clymeniida: Upper Devonian

Goniatitida: Middle Devonian - Upper Permian

Prolecanitida: Upper Devonian - Upper Triassic

Ceratitida: Upper Permian - Upper Triassic

Ammonitida: Lower Jurassic - Upper Cretaceous

If they are geometric with numerous undivided lobes and saddles and eight lobes around the conch, we refer to their pattern as goniatitic, a characteristic of Paleozoic ammonites. 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. Ammonites were skilled and successful hunters. They caught their prey while swimming and floating in the water column. This cluster of ammonites cemented together in death would have hunted our ancient seas as keen predators.

MARINE REPTILES OF THE HUMBOLDTS

A very well preserved ichthyosaur block with three distinct vertebrae and some ribs just peeking out. You can see the edges of the ribs nicely outlined against the matrix.

Ichthyosaurs are an extinct order of marine reptiles from the Mesozoic era. They evolved from land-dwelling, lung-breathing reptiles, they returned to our ancient seas and evolved into the fish-shaped creatures we find in the fossil record today.

They were visibly dolphin-like in appearance but seem to share some other qualities as well. These lovelies were warm-blooded and used their coloration as camouflage. The smaller of their lineage to avoid being eaten and the larger to avoid being seen by prey. Ichthyosaurs also had insulating blubber, a lovely adaptation to keep them warm in cold seas.

Over time, their limbs fully transformed into flippers, sometimes containing a very large number of digits and phalanges. Their flippers tell us they were entirely aquatic as they were not well-designed for use on land. And it was their flippers that first gave us the clue that they gave birth to live young; a hypothesis later confirmed by fossil embryo and wee baby ichy specimens.

We find their fossil remains in outcrops spanning from the mid-Cretaceous to the earliest Triassic. As we look through the fossils, we see a slow evolution in body design moving towards that enjoyed by dolphins and tuna by the Upper Triassic, albeit with a narrower, more pointed snout. During the early Triassic period, ichthyosaurs evolved from a group of unidentified land reptiles that returned to the sea. They were particularly abundant in the later Triassic and early Jurassic periods before being replaced as a premier aquatic predator by another marine reptilian group, the Plesiosauria, in the later Jurassic and Cretaceous periods.

The block you see here is from Middle Triassic (Anisian/Ladinian) outcrops in the West Humboldt Mountains, Nevada.

SUNRISE FORMATION, NEVADA

At the entrance to the Pliensbachian-Toarcian localities at Joker Peak and Mina Peak Members of the Sunrise Formation, Nevada, USA.

The ammonites of this section were first studied by Dr. Paul Smith, past Chair of Earth and Ocean Sciences, University of British Columbia and more recently by Andrew Caruthers et al.

Caruthers and his team also took a goodly look at the Early Jurassic coral fauna. Caruthers is an interesting cat. He uses a combination of invertebrate paleontology and isotope geochemistry to ponder the effects of paleoclimate change and mass extinction. He's turned his eye in recent years to the Paleozoic of the Michigan Basin AND he's based in Kalamazoo, MI. Yep, Kalamazoo.

Others have taken up the mantle of discovery from these sites. Pengfei Hou did his 2014 Masters thesis comparing the Sinemurian (Early Jurassic) stratigraphic sections of Last Creek, British Columbia and Five Card Draw, Nevada including a detailed taxonomic study from the Involutum Zone to the lower part of the Harbledownense Zone of the Sinemurian.

DUBIOUS DAONELLA DUBIA

Triassic ammonoids, West Humboldt Mountains, Nevada, USA. This was 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.

Paleontologist J.P. Smith joined that expedition and published on the marine fauna in the early 1900s.

They formed the basis for his monograph on North American Middle Triassic marine invertebrate fauna published in 1914. N. J. Siberling from the US Geological Survey published on these outcrops in 1962. His work included nearly a dozen successive ammonite faunas, many of which were variants on previously described species.

Evidently, his collections consisted mainly of weathered material and were made without stratigraphic control because he believed that most, if not all, of these species, were coexistent. The fossiliferous beds found here, as well as localities in north-western Nevada, were designated the 'Daonella dubia' zone. Dubious would be closer to the truth. We've since mapped them out from stratigraphic sections to place them in the correct order of their occurrence.

SMILODON FATALIS

During the last ice age, huge cats bigger than an African lion prowled Alberta, including the fearsome beast commonly known as the sabre-toothed tiger.

The proper name for the extinct predator with foot-long, serrated knife-like canines is Smilodon fatalis.

Up until the discovery of the fossil from Medicine Hat, Alberta, the species had never been found further north than Idaho. Or so it was thought...

A few years ago, a few small fossils caught the eye of researcher Ashley Reynolds as she was rummaging through the drawers at the Royal Ontario Museum in Toronto. The drawer was part of a treasure trove of 1,200 specimens collected in the 1960s by University of Toronto palaeontologist C.S. Churcher and his team. The specimens were collected over many field seasons along the bluffs of the South Saskatchewan River near Medicine Hat.

Churcher was a palaeontologist with a keen eye and a delightful man. I had the very great pleasure of listening to many of his talks out at UBC and at a few VanPS meetings in the mid-2000s. "Rufus" was a thoroughly charming storyteller and shared many of his adventures from the field. He moved out to the West Coast for his retirement but his keen love of the science kept him giving talks to enthralled listeners keen to hear about his survey of the Dakhleh Oasis in the Western Desert of Egypt, geomorphology, stratigraphy, recent biology, Pleistocene and Holocene lithic cultures, insights learned from Neolithic Islamic pottery to Roman settlements.

The specimens he had collected had been roughly sorted but never examined in detail. Reynolds, who was researching the growth patterns and life histories of extinct cats by looking at their bones, decided to look more carefully at the fossils Churcher had found, keen to add them to her research. And what a find she made!

One of the fossils labelled Smilodon was too small a piece to be identified. But another, a bone from the ancient cat's right front paw, was identical to other Smilodon bones and was positively identified as Canada's first Smilodon. CBC did a nice write up on her discoveries. 

References:
https://www.cbc.ca/n…/technology/sabre-toothed-cat-1.5305505

LATE HETTANGIAN TO EARLY SINEMURIAN FAUNA

Hiking the hills of Nevada looking for David Taylor's faunal succession based on ammonoids established for the Late Hettangian to Early Sinemurian interval in the Western Cordillera.

It was a tremendous experience to walk through time and compare the fossil assemblages here with our own in the Canadian Rockies.

Here the faunal sequence consists of one zone and four informal biochronologic units or assemblages and was outlined by Taylor as follows: Paracaloceras morganense assemblage, Badouxia oregonensis assemblage, Canadensis Zone, Metophioceras trigonatum assemblage and Coroniceras involutum. They matched up to specimens we collected over three field seasons to similar faunal outcrops of Late Hettangian to Early Sinemurian of the Last Creek and Tyaughton area of the Canadian Rockies.

The succession also correlates with the interval delineated by the Northwest European Angulata Zone through the Lyra Subzone. Two new genera (Guexiceras and Tipperoceras) are described along with 23 new species. The phylogenetic relationships of the earliest Jurassic ammonite superfamilies indicate that it is useful to include under the Psiloceratida, the Psilocerataceae and their derivatives including the Lytocerataceae. The Arietitaceae were derived from Hettangian lytocerataceans.

CAMBRIAN ARTHROPODS OF THE BALANG

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 earlier this week. 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.

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.

LATE SILURIAN EURYPTERID

The impressive homeotype specimen of Eurypterus lacustris from Late Silurian deposits in New York. UCMP Berkeley's paleontological collections.

About two dozen families of eurypterids “sea scorpions” are known from the fossil record. Although these ancient predators have a superficial similarity, including a defensive needle-like spike or telson at their tail end, they are not true scorpions. They are an extinct group of arthropods related to spiders, ticks, mites and other extant creepy crawlies.

Eurypterids hunted fish in the muddy bottoms of warm shallow seas some 460 to 248 million years ago before moving on to hunting grounds in fresh and brackish water during the latter part of their reign. Their numbers diminished greatly during the Permian-Triassic extinction, becoming extinct by 248 million years ago.

ESMERALDINA ROWEII

An Esmeraldina roweii multi-block of lovely trilobites from the Lower Lower Cambrian Poleta Formation of Esmeralda County, near Goldfield Nevada, plus a very interesting creature off to the lower left who looks to be an unidentified arthropod.

A very developed trilobite with long genal and axial spines, plus the ability to enroll. And all of this before the Olenellids existed. Collection of the deeply awesome George Walter Ast. Goldfield is located 247 miles southeast of Carson City, along U.S. Route 95.

MAMMUT AMERICANUM

The American Mastodon, Mammut americanum. Mastodons resemble elephants, but are more like elephant cousins.

A second species, Mammut pacificus, has recently been described from fossils found in Idaho and California. This specimen can be seen at the Smithsonian National Museum of Natural History. Photo credit: Guy Leahy.

MIDDLE TRIASSIC OF NEVADA

Searching for bedrock in outcrops of the West Humboldt Mountains, Nevada. Perhaps the most famous and important locality for the Middle Triassic (Anisian/Ladinian) of North America. These beautiful hills are home to Triassic ammonoid outcrops and plentiful ichthyosaur fossils.

J.P. Smith published on the marine fauna in the early 1900's. They formed the basis for his monograph on North American Middle Triassic marine invertebrate fauna published in 1914. N. J. Siberling from the US Geological Survey published on these outcrops in 1962. His work included nearly a dozen successive ammonite faunas, many of which were variants on previously described species.

Evidently, his collections consisted mainly of weathered material and were made without stratigraphic control because he believed that most, if not all, of these species were coexistent. The fossiliferous beds found here, as well as localities in north-western Nevada, were designated the 'Daonella dubia' zone. Dubious would be closer to the truth. Smith joined 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.