[coldcreation]

Hello all,

Upon one of my recent expeditions to deep Spain (Alto Tajo) I came across a site where fossils were known to be found: Graptolites.

See Graptolite, From Wikipedia, the free encyclopedia.

Graptolites (Graptolithina) are fossil colonial animals known chiefly from the Upper Cambrian through the Lower Carboniferous (Mississippian). A possible early graptolite, Chaunograptus, is known from the Middle Cambrian.

The name graptolite comes from the Greek graptos, meaning "written", and lithos, meaning "rock", as many graptolite fossils resemble hieroglyphs written on the rock. Linnaeus originally regarded them as 'pictures resembling fossils rather than true fossils', though later workers supposed them to be related to the hydrozoans.

So I started digging and came up with quite a few examples (see below).

There were also present a number of sponge fossils with remaining organic material embedded within the shale stone, shell fossils, as well as extremely primitive fish samples: Pikaia, one of the oldest known Chordates, primitive chordates, Lancelets, Branchiostoma, Amphioxus: small marine animals with fish-like bodies, notochord and Pikaia with segmented muscles, armored jawless fishes called the ostracoderms, (some look like the world's oldest known fish: Myllokunmingia), though the quality of the latter left a little to be desired. (If anyone is interested I can post the photos of these too).

The following examples are graptolites, the find-location of which is also pictured.

These are from the Paleozoic Era (544 to 251 mya): More precisely, these particular graptolites are from the Silurian (440 to 410 mya) and Ordovician (500 to 440 mya).

Shale stone hills in Alto Tajo Spain.





Graptolite fossils. The above example is about 6 inches long.




Graptolite fossils. The above example is about 15 inches long

Graptolite fossils. This specimen is about 13 inches long.

I was thinking of donating these and other examples to a Biology museum here in Barcelona. I have no idea if they will be interested. I'll have to see if they have any on display. It may be that other creatures are more interesting (e.g., Trilobites etc.).

I am curious to know if anyone is interested in the proliferation of primitive life forms in this Era. Any comments or questions?


CC

[mynah]

Most sources classify graptolites as pterobranchs, rather than hydrozoans (which makes them relatively close relatives of our vertebrate selves!)

And they may not be extinct.

[coldcreation]

Originally Posted by mynah

Most sources classify graptolites as pterobranchs, rather than hydrozoans (which makes them relatively close relatives of our vertebrate selves!)

And they may not be extinct.

Interesting.

So, some of the Graptolites distant relatives (within pterobranchia) continued to proliferate and (to make a long story short) evolved into creatures capable of playing Ludwig van's Moonlight Sonata 3rd Movement.

Sweet.

This article struck me as interesting too TEXT-BOOK OF PALEONTOLOGY:

Life-Period and Extinction of Species. — Observation shows that different organisms are by no means equally susceptible to impulses received from the outer world. Many fossil genera remain almost wholly unchanged throughout a number of formations (Foraminifera, Cidaris, Nautilus, Lingula, Terebratula, Insectivora),and hence may be designated as j^ersisfent or conservative types, in contradistinction to variable types. The latter pass through rapid changes at the beginning of their career, develop a great variety of forms, and send out branches and off-shoots in all directions up to a certain point ; they may then die out after a comparatively short period of ascendency (Nummulites, Graptolites, Cystids, Blastoids, Tetracoralla, Perischoechinoida, Trilobitae, Eudistae, Ichthy o-sauria, Pterosauria, Dinosauria, Amblypoda, Toxodontia, etc.), or in some cases may even continue on to the present day with undiminished vitality (Spatangidae, Clypeastridae, many land and fresh-water mollusks, crabs, lizards, snakes, ruminants, apes). Not infrequently types that were originally variable pass over gradually into persistent ; their power of adaptation dwindles, they grow less plastic, become incapable of sending off new varieties, species or genera, and as the less vigorous of their numl)er become worsted one after another, they finally stand out as isolated relics of antiquity (Isocrinus, Hatteria, Tapirns, Equus, etc.) in the midst of rehabilitated surroundings.

And, is this same text book it is written about Graptolites:

Under the term of Graptolitoidea are included organisms which have been considered by various authors as plant remains, horny sponges, Pennatulidae, Cephalopods and Bryozoans. Portlock, in 1843, first pointed out their analogy with the Sertularians and Plumularians ; and his inferences as to their genetic relationship were afterwards confirmed by the painstaking researches of Allman, Hall, Hopkinson, Lapworth, Nicholson, and others. More recently, however, their kinship has been denied by Neumayr and Wiman, who, on account of the bilateral symmetry of the sicula and thecae, claim that Graptolites cannot be included within any of the now existing classes of organisms...

...Graptolites commonly occur in argillaceous schists, more rarely in limestone formations, of the Upper Cambrian, Ordovician and Silurian systems. They seem to have swarmed in the muddier portions of the sea, and floated either attached to sea-weeds, etc., or as free-swimming colonies ; or, in rarer instances, remained stationary with the sicula or a root embedded in the mud, or attached to foreign bodies. They are divided into two orders : Dendroidea Nicholson {CladoplLora Hopkinson), and Graptoloidea Lapworth, or Graptolites proper.

And this source confirms more or less what you write above:

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 hemicordates (phylum hemicordata), a primitive group which probably shares a common ancestry with the vertebrates.

CC

[mynah]

Interesting stuff. Have to admit at this point, though, I was first alerted to their existence when they featured as the Fridge Fauna in the ancient animation TV series Dinosaurs. I only discovered later that they really did exist!