Friday, January 12, 2018

California's Official State Dinosaur

In 2017, the State of California declared its official state dinosaur to be Augustynolophus morrisi Prieto-Márquez et al. (2014), a duck bill of Late Cretaceous age. Duck bills are classified as hadrosaurs.
The generic name, Augustynolophus Prieto-Márquez et al., 2014, is a combination of the Augustyn family, who helped support the Los Angeles County Museum of Natural History, and the suffix “lophus,” in reference to its similarity to Saurolophus, another duckbill, 30 to 40 feet in length, bipedal, and with a battery of flat teeth used for chewing coarse vegetation.  

Augustynolophus, like Saurolophus, has a bony, spikelike crest that projects up and back from the top of the skull. This spike is an extension of the nasal bones.

Augustynolophus morrisi is of late Maastrichtian age, about 68 million years old. The geologic time diagram below depicts the recognized intervals of time that constitute the Late Cretaceous. The Maastrichtian was the last stage of the Late Cretaceous. The red star indicates the approximate occurrence of this dinosaur.

The bones of A. morrisi have been found in the Moreno Formation along the west side of the San Joaquin Valley, Fresno County, central California.

In terms of vertebrate (back-boned) fossils, the Moreno Formation is mainly known for its marine-reptiles (plesiosaurs and mosasaurs). It also contains marine-mollusk fossils (oysters, other bivalves, and gastropods). Augustynolophus morrisi lived in a  marshy, coastal area.

Augustynolophus morrisi is endemic (only found) in California.
For excellent copyrighted pictures of this dinosaur, also known as "Auggie," just "Google" its scientific binomial (two-part) name.

The species name, morrisi, is in honor of the late William J. Morris (1923-2000), a highly respected vertebrate paleontologist who had many dinosaur and other vertebrate-fossil discoveries on the west coast of North America, especially in Baja California, Mexico. His final teaching position was at Occidental College in the Eagle Rock neighborhood of Los Angeles, California. He was also a Research Associate in Vertebrate Paleontology at the Natural History Museum of Los Angeles County.

If you want to see  the entire list of official California names of other geologic entities, go to <>, and click on the associated thumbnail images in order to see larger images. 

Thursday, December 28, 2017

An Eocene crab from southern California

If a collector is fortunate, some localities yield a few fossil crabs. This post is about a species of crab, Orbitoplax weaveri (Rathbun, 1926) which can be found in Eocene (approximately 50 million year old) rocks on the west coast of the United States, from southwestern Washington to southern California.

Orbitoplax weaveri is the updated genus name of this crab. It has been erroneously placed in other genera, thus in the older literature this species was called Plagiolophus weaveri and then Glyphithyreus weaveri.

The main part (carapace) of this recently collected specimen is 22 mm (nearly an inch) wide. There are also parts of three of its legs on the left side of the specimen. The collector who found and photographed the specimen kindly gave it to me.

This is another picture of the carapace of the same specimen, after it was removed from the rock. This picture was taken under low-angle lighting to show the sculptural details.

This is another and larger (main part 25 mm) specimen of O. weaveri, which I collected many years ago from the same locality as the one shown above. Its right pincher is intact. Also, a impression of the claw part of the left pincher is present. The total width (from left to right) of the specimen is 55 mm. 

Complete or nearly complete crabs like the ones shown above are typically found in silty sands, which were deposited under relatively quiet-water conditions. Just down section a few meters, there are storm beds with numerous Turritella gastropods, whose shells display preferred orientation caused by current action.

Monday, December 11, 2017

A 50-million year old chambered nautiloid shell

The living "pearly nautilus," also called the "chambered nautilus," is a favorite seashell of many collectors. Today, the biodiversity (number of species) of these animals is very low, and they are confined to tropical waters in the equatorial region of the western Pacific. As certain times in the geologic past, however, when warm oceans extended north and south of where they are now, chambered shells similar to the "pearly nautilus" had high biodiversity, and their distribution was widespread (cosmopolitan). These chambered shells are commonly referred to as coiled nautiloids.

On August, 2016, I created a post about the "pearly nautilus," and two of my pictures are shown again here for comparative purposes. I encourage you to use the "search box" at the top right-hand side of this blog page to find this post and read it again. I also give some interesting details about the life habits of this animal.

Exterior of a modern-day "pearly nautilus."
            Maximum diameter is 14 cm

Interior of same specimen shown above 

This present post concerns one of these ancient widespread groups of coiled nautiloids, namely, an extinct genus belonging to genus Aturia Bronn, 1838.  It was widespread (cosmopolitan) and its geologic time range was Paleocene to Miocene (approximately 40 million years long).

In particular, this post is about Aturia myrlae Hanna, 1927, an early to middle Eocene species of genus Aturia. The ancient geographic distribution of this species covered an area now referred to as central California, southern California (including Ventura, Los Angeles, and San Diego counties), and Baja California Sur, Mexico. Aturia lived in subtropical to tropical ancient environments. So, if you are lucky enough to find one of these fossils, you can be certain that it represents a warm-water ancient environment. Specimens are not that common because, like other coiled nautiloids, Aturia was a predator, thus, their numbers were few.

The next three pictures show a partial specimen of Aturia myrlae from Simi Valley, southern California. The widest dimension (diameter) of this incomplete specimen is 14 cm. 

Side view showing the complex outlines (septal pattern or suture pattern) of the chamber walls (septa). The suture pattern of Aturia is a very distinctive character of this genus and is in sharp contrast to the simple-curved suture pattern of the "pearly nautilus," which belongs to genus Nautilus.

Back side view of the same specimen. 

Front view of the same specimen. Notice the presence of the siphuncle (see a reference picture at the beginning of this post), which was a hollow tube that connected all the empty chambers and allowed for nitrogen gas to be dispersed to all the chambers. In so doing, the shell achieved buoyancy when the gas was pumped in, and the shell sank when the gas was pumped out. The shell could, therefore, move up and down in the water column.

Monday, November 27, 2017

Colors of scallops

If you have been reading my latest posts, you will know that I have been focusing on colors in certain minerals. In this present post, I shall discuss colors of certain clams called scallops, which belong to the family Pectinidae. The family is comprised of many genera.  Those belonging to genus Pecten are called pectens (not: pectins, which refers a group of colloidal substances used to jell various foods or cosmetics). 

Pectinids are especially abundant as fossils, if found in the right environment. Their geologic time range is Triassic to modern day. Along the west coast of the USA, fossil pectinids are  common in sediments of Miocene and Pliocene age (20 million to about 3 million years ago). Today, the strong muscle that holds the two valves together is a popular seafood delicacy. 

The two valves of a pectinid are referred to as the left and right valves. 

In addition to the primary (radial) ribs, important morphologic parts of a pectinid are the auricles ("ears") along the hinge line. As shown above, on the right valve, the anterior auricle is the most elongate. On some pectinids a byssal notch is located directly below the elongate anterior auricle. This notch is where the byssus (a bundle of hairlike material used for attachment) exits the shell.

Today, there are approximately 250 species of pectinids. Some have shells which are bright orange, yellow, red, blue, purple, brown, white, or combinations thereof. This color variation comes mainly from heredity although environment can play a role (e.g., some muddy-bottom pectinids have darker color than sandy-bottom pectinids.

The four colored specimens (each one is about 5 cm width) shown above are of species of the pectinid Chlamys, and they show some of the variation in the color. Some people think that they are hand painted, but the colors of these specimens occur naturally. Chlamys lives by having its byssus attached to a rock, shell, or other hard surface.

These are the right (= the specimen on the left side of this image) and left valves of a modern specimen of Chlamys hastata (2.7 cm wide), dredged from 210 feet depth, at the shelf break just south of Long Beach, southern California.

Nodipecten subnodosus, 15 cm wide, exterior and interior of a right valve. This species is most commonly found in modern waters in the Gulf of California, Mexico.

Nodipecten has been observed anchored by a byssus to hard substrates, but they have been observed also to have the ability to swim for short distances. At least temporarily, therefore, they are not anchored by a byssus. Thus, its byssal notch is not well developed. Nodipecten swims by pulsatory clapping together of their valves. This swimming action is exhausting and cannot be sustained for very long; it is normally used only to escape from predators (e.g., sea stars).

Patinopecten caurinus (Gould, 1850), 16.5 cm wide, exterior of a large right valve modern-day specimen from Skagway, Alaska. Patinopecten has a well developed byssal notch, therefore, it lived by attaching to hard surfaces. 

Patinopecten caurinus, 16 cm wide, exterior of a large right valve fossil specimen from a late Pliocene (3 million years old) bed found between Goleta and Santa Barbara, California. If you look carefully, you can see the minute daily growth lines of this shell.

Saturday, November 11, 2017

Barnacles make interesting fossils

Barnacles are classified as cirriped crustaceans and belong to phylum Arthropoda (a large group that also includes trilobites, crabs, insects, etc.). The name "cirriped" (cirri, curl; ped, foot) refers to the six pairs of delicate appendages which are used for filter feeding.

Barnacles are not very different from other arthropods in that they hatch as an egg, have a short existence as free-swimming larval forms, and molt (shed) to grow larger. In adult life, however, barnacles do not resemble other arthropods at all. With a shelly (calcareous) covering of many plates enclosing their shrimp-like body, most barnacles grow attached to hard substrate. Genus Megabalanus Hoek, 1913one of the so-called “acorn" barnacles, is common in the fossil and modern-day record of the eastern Pacific. 

Few people know that Charles Darwin, yes, that Charles Darwin, was an expert on barnacles. He derived some of his concepts about evolution based on his detailed studies of them.

bivalve shell is 3.4 cm in diameter
A bivalve shell (the "jingle" shell Anomia) with a large Megabalanus base (circular) at the top of the shell and 15 Megabalanus shells elsewhere on the shell. These fossils are of late Pleistocene age from the vicinity of Long Beach, Los Angeles County, southern California.

large barnacle is 1.5 cm high 
Megabalanus shell encrusting a shallow-marine gastropod shell, and a small Balanus shell encrusting the larger Megabalanus shell. All of these fossils are of late Pleistocene age from the same locality as those shown in the previous image.

acorn-barnacle operculum: smaller parts are 4.5 mm length;
 larger parts are approximately 5.5 mm length
Covering the top of an acorn-barnacle shell is a calcareous structure consisting of four interlocking plates. These two pairs of plates close together, just like a tight-fitting “lid,” used when the barnacle is not feeding or when it is disturbed. The opercular plates, which show continuous growth records (like tree rings) and are not shed during molting. Upon death of the animal, these plates eventually fall apart, thus they are mostly missing on fossil barnacles. The pair of plates shown (above) on the left are called terga, and those on the right are called scuta.

cluster is 2.2 cm wide
 The image shown above is a small cluster of modern-day barnacles with their opercular plates in life position. These are specimens of Balanus amphitrite saltonensis Rogers, 1949 from the Salton "Sea," an inland lake with very salty waters in southeastern California. This lake was created by accident in the early 1900's, when an aqueduct overflowed. This subspecies of barnacle, which is closely allied to the globally widespread B. a. amphitrite Darwin, 1854, was  introduced into the lake. This introduction was most likely via  migratory water birds.

cluster is 21 cm in maximum dimension
A cluster of five large-sized Tamiosoma gregarious from Pliocene rocks in the central San Joaquin Valley of central California.

each component is 2.8 cm length
These four images above show the exterior (above) and the interior (below) of two scuta of Tamiosoma gregarious found in Pliocene beds in the central San Joaquin Valley of central California. These are unusual finds.

2.6 cm height
This is the side view of a modern-day "gooseneck" barnacle (Pollicipes polymers) from a rocky intertidal zone in the vicinity of Goleta, Santa Barbara County, California. Notice the leathery stalk (pedicle) which is used by the barnacle to attach to rock. The stalk does not get preserved, thus, in the fossil record all one can find are the individual calcareous plates that make up the upper part of the animal.

The geologic time range of barnacles is Paleozoic (Silurian) to Holocene [= modern day]. Gooseneck barnacles evolved first. "Acorn" barnacles did not appear until the early Cenozoic.

3.5 cm maximum diameter
Lastly, I show an image of the barnacle genus Chelonibia, which attaches to the carapaces of sea turtles. This modern-day specimen is from Baja California Sur, Mexico.

Saturday, October 28, 2017

Colors of fluorite

The mineral fluorite consists of calcium fluoride (CaF2). It can have variation in color, largely due to impurities in its crystal structure. Flourite can be found throughout the world. It is common in hydrothermal deposits, where it can be associated with quartz, calcite, baryte, and galena (lead sulfide). 

Uses of fluorite include jewelry making, as well as a flux for smelting. 

The largest crystal (green color one) is 4 cm long.

Flourite can crystallize in several forms, including the octahedral form, which is my favorite.
Octathedral crystals: the clear one is 3 cm tall.

Flourite has a hardness of four on the Mohs Scale. Optically clear crystals, like the one shown above, has low aberration, thereby making them valuable in the construction of microscopes and telescopes.

Saturday, October 14, 2017

Copper and Molybdenite

COPPER (Cu) is a naturally occurring pure element with a reddish-orange color.

This is the element copper in its pure natural form. The specimen, which is 5 cm long, shows the dendritic habit of copper. The gray material is gangue (wall rock) material consisting of calcite.

Copper has with very high electrical and thermal conductivity, and the main uses for this soft element are for electrical wire, plumbing parts, and industrial machinery. In order to make copper harder, it is purposely combined (alloyed) with other metals:

brass = an alloy of copper and zinc

bronze = an alloy of copper and  tin

cupronickel = alloy of copper and nickel (used in making coins, like the U.S. nickel = 75% copper and 25% nickel).

Copper is one of the few metals that occurs naturally as a directly usable form. This led to its being used by early humans, as far back as 9000–8000 BC. The discoveries of making alloys out of copper happened later (e.g., the Bronze Age about 3700–100 BC).

Like aluminum, copper is readily recyclable without any loss in quality. It has been estimated that 80% of all copper ever mined is still in use today.

MOLYBDENITE (MoS2is the mineral molybdenum sulfide, the principal source of the metallic element molybdenum. This high-temperature hydrothermal mineral is silvery/gray in appearance (similar to graphite = pencil "lead"), is greasy to the touch, and peels apart (in one direction) in somewhat heavy but flexible sheets.

This specimen of molybdenite is 4 cm long (from upper left to lower right).
Molybdenite can withstand extreme temperatures without significantly expanding or softening. The element molybdenum  readily combines with other elements and forms hard, stable alloy materials, which are used for making high-strength steel. In particular, these alloys are used in military armor, aircraft parts, electrical contacts, industrial motors, etc. 

This specimen came from a quartz veinlet in granite at a commercial mine in Climax, Colorado.