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This specimen, preserved in exquisite detail, is a window into the complex colonial life forms that once drifted through the ancient oceans of Gondwana.
Graptolites (Graptolita) were colonial marine animals, each “colony” composed of numerous tiny individuals called zooids that lived within cup-like structures known as thecae. These thecae were arranged along a central organic skeleton called the stipe, forming intricate branching or saw-blade–like patterns. For centuries, graptolites puzzled paleontologists — were they plants, corals, or something else entirely?
Early researchers classified them as hydrozoans, but modern studies using ultrastructural and biochemical evidence have firmly placed them within the phylum Hemichordata, closely related to modern pterobranchs such as Rhabdopleura. This group, in turn, shares a distant ancestry with the vertebrates, linking these delicate fossils to our own deep evolutionary story.
In life, many graptolites were planktonic, drifting through Ordovician seas suspended from delicate threads or attached to floating seaweed, catching microscopic food particles as they went. Others were benthic, anchored to the seafloor by root-like structures. When they died, their lightweight colonies slowly sank to the ocean floor. Over time, fine muds buried them, and the soft organic skeletons became flattened and carbonized, leaving the characteristic dendritic or “tuning fork” impressions we see in shale today.
The diversity of graptolite morphology is remarkable — from the feathery fronds of Dictyonema to the elegant bifurcations of Didymograptus murchisoni.
Isograptus cf. maximus, however, stands out even among this varied group. With its bold, symmetrical “wings,” it bears an uncanny resemblance to a stylized emblem — reminiscent of the Batman symbol, the Panem Mockingjay of The Hunger Games, or even an abstract eagle in flight. These forms, though purely natural, invite the human imagination to see something mythic in their symmetry.
This particular specimen, now part of the superb private collection of Gilberto Juárez Huarachi of Tarija, Bolivia, showcases the grace and geometric beauty that made graptolites not only essential tools for Ordovician biostratigraphy but also enduring icons of paleontological art.
Long extinct, they nonetheless continue to “signal” to us across deep time — reminders of the ancient, drifting colonies that once filled the world’s primordial seas. And, they will always be a favourite of mine as finding my first graptolite remains one of my fondest paleo moments!
