TYLOSTOMA TUMIDUM

This lovely big fellow is Tylostoma tumidum, an epifaunal grazing Lower Cretaceous Gastropod from white, micritic, coarsely nodular limestone deposits of the Goodland Formation at White Settlement west of Fort Worth, Texas, USA. (171.6 to 58.7 Ma).

The bedding here is massive with some thin clay beds. The macro fossil found here include the ammonite, Oxytropidoceras acutocarinatum, pelecypods such as Protocardia, Pinna and Lima wacoensis along with heart-shaped urchins in abundance and lovely gastropods such as this beauty, Tylostoma tumidum. This specimen shows the wear and tear of erosion common at the site.

Tylostoma have thick, smooth shells with a moderately elevated spire. Their aperture is ovato-lunate with the lips meeting above at a sharp angle. The outer lip is furnished internally, running the whole length and ending with a nice thickened edge. This chunky specimen is about 3 inches tip to tip.

ANCIENT PLANKTON HUNTER

Pentremites sp. / Hardin County, Kentucky

This wee lovely Blastoid is Pentremites sp. from Mississippian deposits in Hardin County, Kentucky. This little fellow represents a specimen from the peak of their diversity in the Mississippian.

Blastoids are an extinct type of stemmed or stalked suspension feeding echinoderms, sometimes referred to as "sea buds."

They made a living feeding on planktonic organisms that inhabited our ancient seas from shelf to basin. Their lineage dates back to the Ordovician and died out at the end of the Permian, about 250 million years ago. This little guy measures 10mm top to bottom and 5mm at his widest.

TRAGOPHYLLOCERAS LOSCOMBI

Tragophylloceras loscombi / Dorset Coast

A very interesting Tragophylloceras loscombi (134 mm with the peristome / 41 mm) from Lower Pliensbachian deposits near the coastal village of Seatown near Charmouth on the Dorset coast of the UK.

This lovely specimen is in the collection of the deeply awesome José Juárez Ruiz. He was amongst the many belemnite guards and ammonite shells of this lovely collection spot. Both beautiful in and of itself and highly prized for its fossil finds along the silty mudstone cliffs and fossiliferous boulders.

This fellow like to live in the offshore, deep subtidal shelves of our ancient seas around 189 to 183 million years ago.

He was a nektonic carnivore, an active swimmer cruising our ancient seas looking for tasty daily sustenance. Ammonites belong to the class of animals called mollusks. More specifically they are cephalopods and first appeared in the lower Devonian Period. Cephalopods were an abundant and diverse group during the Paleozoic Era.

Varying in size from millimeters to meters across, these elegant marine dwellers are prized as both works of art and index fossils helping us better understand and date strata. Cousins in the Class Cephalopoda, meaning "head-footed," ammonites are closely related to modern squid, cuttlefish and octopus with complex eye structures and advanced swimming abilities. They used these evolutionary benefits to their advantage, making them successful marine predators cruising our ancient oceans expertly capturing prey with their tentacles.

PLATRYACHELLA: DEVONIAN BRACHIOPOD

Platryachella sp. / Devonian Brachiopod

This fellow is Platyrachella sp. a brachiopod from Middle Devonian deposits of the renamed the Little Cedar Formation, Cedar Valley Group (probably out of the Solon Member) near Benton County, deep in the agricultural belt of east-central Iowa.

Driving through Benton you see long, gently rolling slopes, farms of corn and soybean growing in deep black soil.

Benton also has three very productive quarries that produce limestone, gravel and clay for industrial uses. While the quarries focus on the commercial aspects of the many varieties of limestone produced there, they also boasts some very nice macro fossils like the brachiopod specimen you see here. While brachiopods share some similarities with their molluscan friends they are in a phylum all their own. Clams or bivalves are molluscs, the second-largest phylum of invertebrates with about 85,000 extant species.

Brachiopods are small marine shellfish that are not so common today but back in the Palaeozoic they were plentiful the world over. The two valves that make up a brachiopods shell are of different sizes and if you look closely you'll see that the hinge runs top and bottom  -- versus left and right like a clam.

Brachiopods have been with us a long time. Their lineage dates back to the Cambrian with over 12,000 fossil species and 350 living species sorted between 6,000 genera. There are two major groups of brachiopods, articulate with toothed hinges and simple open and closing muscles to manipulate their shells and inarticulate brachiopods with untoothed hinges and a more complex set of muscles used to control the brachial supports used to open and close their shells. This specimen is 7cm long and about 2.5cm deep