THE FIRST PREDATOR: ANOMAOLCARIS!

DAS ERSTE RAUBTIER: ANOMALOCARIS!

 

The Anomalocarididae are known from the Lower Cambrian up to the Lower Devonian. I want to document the different types of this first predator in the different times. As far as I know there exists a gap in the Silurian. I hope diggers will fill it soon...

Die Anomalocarididae sind vom unteren Kambrium bis hinauf ins uhtere Devon bekannt. Ich möchte die uhnterschiedlichen Typen des ersten Raubtiers in den unterschiedlichen Zeiten dokumentieren. Sowiet ich weiß, gibt es da eine Lücke im Silur. Ich hoffe, dass diese Lücke bald gefüllt wird...

THE EXCITING STORY OF ANOMALOCARIS CANADENSIS

Anomalocaris canadensis (Whiteaves, 1892) grasping claw (~8.5 cm long), preserved as a carbonized film in slightly metamorphosed shale from the Middle Cambrian-aged Burgess Shale of southwestern Canada (YPM 35138, Yale University’s Peabody Museum, New Haven, Connecticut, USA).

The Middle Cambrian-aged Burgess Shale is the most famous fossil deposit on Earth. It is located near the town of Field in Yoho National Park, southeastern British Columbia, western Canada. The deposit is famous for its spectacular soft-bodied preservation - the organisms have had their appendages & internal organs preserved. Many tens of thousands of fossils have been collected from the Burgess Shale Formation over the last century. Including known, but unnamed species, and excluding known or demonstrable junior synonyms, the Burgess Shale biota totals at least ~280 species.

Many claim that Charles Walcott discovered the Burgess Shale Lagerstätte (as soft-bodied fossil deposits are called by paleontologists) in 1909. However, it was actually discovered in 1886 or 1888 by Richard McConnell, based on anomalocarid appendage material from Mt. Stephen, in the Campsite Cliff Member of the Burgess Shale Formation. The main collecting localities have been two quarries (Walcott Quarry & Raymond Quarry) on the western side of the ridge connecting Mt. Field and Wapta Mountain a little north-northeast of Field. Numerous other smaller localities have been identified in the same area & for many, many kilometers to the south. Collecting at the Burgess Shale was most intense in 1910-1917 (Charles Walcott), 1925-1930 (Harvard’s Museum of Comparative Zoology), 1966-1967 (Geological Survey of Canada), and 1975-2000s (Royal Ontario Museum).

Some of the most celebrated problematic fossil organisms from the Burgess Shale are the anomalocarids, the namesake of which is Anomalocaris canadensis Whiteaves, 1892. The genus name “Anomalocaris” means “strange shrimp”, which is ironically appropriate, because the name was given to fossil remains identified as shrimp bodies. But, anomalocarids are anything but shrimp. These creatures had medium-sized to large bodies (extrapolated up to ~3 meters long) with a head having a pair of grasping claws & short-stalked eyes & a pineapple ring-shaped mouth, plus a body with two lateral rows of swimming flaps.

The first anomalocarid fossils (isolated grasping claws) were discovered in the 1880s from British Columbia’s Burgess Shale Formation. They were identified as shrimp bodies lacking heads (see this photo).

In general, paleontologists didn’t recognize that these Anomalocaris fossils represented parts of a much larger organism. The true nature of the complete Anomalocaris organism wasn’t realized until very rare complete specimens were excavated from Burgess Shale quarries by the Royal Ontario Museum. The "headless shrimp" fossils turned out to be grasping claws at the head end of a large animal that could not be classified with any traditional arthropod group. New high-level taxa have been created to accomodate it (see Collins, 1996, Journal of Paleontology 70: 280-293).

Classification: Arthropoda, Dinocarida, Radiodonta, Anomalocaridae

Stratigraphy: Walcott Quarry Member, Burgess Shale Formation, Ptychagnostus praecurrens Interval-zone, lower Marjuman Stage, middle Middle Cambrian.

Locality: Walcott Quarry, western side of ridge between Mt. Field & Wapta Mountain, north-northeast of the town of Field, southeastern British Columbia, southwestern Canada.

Source: Anomalocaris canadensis grasping claw (Burgess Shale Formation, Middle Cambrian; Walcott Quarry, above Field, British Columbia, Canada)
Author: James St. John

NEARLY COMPLETE FOSSIL OF A LITTLE ANOMALOCARIS - THE CAMBRIAN PREDATOR

Raymond Quarry Member of the Burgess Shale; found by my friend Matt Devereux. The size of the "little predator": 16.6 cm. Middle Cambrian. Matt says: "Unfortunately the back end was facing outward on the cliff face. Probably one of the best fossils I’ve ever found." Now in the Royal Ontario Museum. (PICTURE ABOVE)

THE FIRST COMPLETE ANOMALOCARIS FOUND

Image of the first complete Anomalocaris fossil found, residing in the Royal Ontario Museum, Toronto: Anomalocaris canadensis (ROM 51211), complete specimen showing the pair of eyes, claws, lobes and the posterior fan. Specimen length = 222 mm. Raymond Quarry/Burgess. -  © Royal Ontario Museum. Photo: Jean-Bernard Caron / Creative Commons. (PICTURE BELOW)

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MATT'S NUTCRACKER OF THE RAYMOND QUARRY

Matt Devereux found this "nutcracker" (10 cm) in a very small pit that represented "the lowest level we ever reached in the Raymond Quarry, less than 8 m above Walcott’s GML". Matt: "It was a very small excavation - would love to go back and see more of this layer."  It is presented now in the Royal Ontario Museum, Canada. - Caryosyntrips serratus (an Anomalocarid) is known only from a handful of 12-segmented appendages, which resemble nutcrackers, recovered from the Burgess Shale.

TENTACLE OF THE LOWER CAMBRIAN PREDATOR AMPLECTOBELUA / FANGARM DES UNTERKAMBRISCHEN TYPS

This is the tentacle of my anomalocariid Amplectubelua symbrachiata, Lower Cambrian, Maozhuang series, Mantou formation,
Chengjiang Biota, Laiwu area, Shandong/China, 6 cm. Collection and photo/Sammlung und Foto: Troppenz.

AEGIROCASSIS FROM THE FEZOUATA BIOTA WAS NOT A PREDATOR LIKE ANOMALOCARIS

Aegirocassis is a genus of anomalocarid arthropod belonging to the family Hurdiidae that lived 480 million years ago during the early Ordovician. It is known by a single species, Aegirocassis benmoulai. A fossil of A. benmoulai from the Fezouata biota, Morocco was discovered by and named after Mohamed Ben Moula, a fossil collector who recognized its rare characteristics and brought it to the notice of a professional paleontologist, Peter Van Roy, at the Gent University in Belgium.

Aegirocassis took a different route to finding food, choosing to strain plankton from the sea rather than being a pursuit predator like Anomalocaris. The length was described as exceeding 2.0 metres (6.6 ft) in the scientific journal "Nature":
Van Roy, Peter; Daley, Allison C.; Briggs, Derek E. G. (2015). "Anomalocaridid trunk limb homology revealed by a giant filter-feeder with paired flaps". Nature. 522 (7554): 77–80. doi:10.1038/nature14256

Reconstruction: Nobu Tamura, Creative Commons
Fossil photo: fossilmall.com

           

SCHINDERHANNES - A LOWER DEVONIAN ANOMALOCARID

Schinderhannes bartelsi (10 cm) is an anomalocarid known from one specimen from the Lower Devonian Hunsrück Slates. Its discovery was astonishing because previously, anomalocaridids were known only from exceptionally well-preserved fossil beds from the Cambrian, 100 million years earlier. (Credit: Steinmann Institute, University of Bonn / Creative Commons.)

THE SHARP EYES OF ANOMALOCARIS / DIE SCHARFEN AUGEN VON ANOMALOCARIS

Acute vision in the giant Cambrian predator Anomalocaris and the origin of compound eyes

John R. Paterson, Diego C. García-Bellido, Michael S. Y. Lee, Glenn A. Brock, James B. Jago & Gregory D. Edgecombe

Nature volume 480, pages 237–240 (08 December 2011)

Abstract

Until recently, intricate details of the optical design of non-biomineralized arthropod eyes remained elusive in Cambrian Burgess-Shale-type deposits, despite exceptional preservation of soft-part anatomy in such Konservat-Lagerstätten2,3. The structure and development of ommatidia in arthropod compound eyes support a single origin some time before the latest common ancestor of crown-group arthropods4, but the appearance of compound eyes in the arthropod stem group has been poorly constrained in the absence of adequate fossils. Here we report 2–3-cm paired eyes from the early Cambrian (approximately 515 million years old) Emu Bay Shale of South Australia, assigned to the Cambrian apex predator Anomalocaris. Their preserved visual surfaces are composed of at least 16,000 hexagonally packed ommatidial lenses (in a single eye), rivalling the most acute compound eyes in modern arthropods. The specimens show two distinct taphonomic modes, preserved as iron oxide (after pyrite) and calcium phosphate, demonstrating that disparate styles of early diagenetic mineralization can replicate the same type of extracellular tissue (that is, cuticle) within a single Burgess-Shale-type deposit. These fossils also provide compelling evidence for the arthropod affinities of anomalocaridids, push the origin of compound eyes deeper down the arthropod stem lineage, and indicate that the compound eye evolved before such features as a hardened exoskeleton. The inferred acuity of the anomalocaridid eye is consistent with other evidence that these animals were highly mobile visual predators in the water column5,6. The existence of large, macrophagous nektonic predators possessing sharp vision—such as Anomalocaris—within the early Cambrian ecosystem probably helped to accelerate the escalatory ‘arms race’ that began over half a billion years ago.

Picture from: http://blogs.discovermagazine.com/notrocketscience/2011/12/07/anomalocaris-sharp-eyes-predator