The Tulip Beds (Formally known as the "S7 locality") is a fossil locality within the larger Burgess Shale that is located in Canada's Yoho National Park. It is a smaller member of the larger Campsite Cliff Shale Member, which exists above the Yoho River Limestone Member, on top of Mount Stephen. The locality is dated to the Miaolingian epoch of the Cambrian period, around 508 million years old. The beds represent one of the more recently discovered localities from the Burgess Shale, with it being first uncovered in 1983. Fossils from the Tulip Beds are found within multiple separate outcrops: the "Above Campsite quarry" and the "Talus Site". The Tulip Beds have yielded plentiful fossils, with up to 2,553 fossil specimens have been collected from the two outcrops since the localities discovery. The majority of the fossils (up to 70%) are known from the Above Campsite outcrop, with the majority of the collecting occurring between 1983-2010. The locality gained its name due to the copious amount of fossils from the area belonging to Siphusauctum gregarium, a species of stem-group ctenophore colloquially known as the "Tulip Animal". This species is one of the most abundant organisms from the Tulip Beds, with at least 1,133 specimens known from the locality. Due to its stratigraphic location at the base of the Campsite Cliff Shale Member, the Tulip Beds represent one of the oldest localities within the Burgess Shale. Like the majority of the other localities of the Burgess Shale, the ecosystem of the Tulip Beds sat at the base of a large submarine canyon known as the Cathedral escarpment. However, the ecosystem of the beds were more distal to the base of the escarpment compared to the other localites. The ecosystem would've sat under 100 to 300 meters (330 to 1000 feet) of water, either at the margin, or in the Mesopelagic zone. The fauna of the Tulip Beds are dominated by sessile taxa, in terms of overall abundance, with mobile taxa having a slightly greater amount of diversity. The fauna of the Tulip Beds is made up of both taxa found in other localites of the Burgess Shale, and other taxa known only from this locality.
Location and stratigraphy
The Tulip Beds were first discovered in 1983, making it one of the more recently discovered localities of the Burgess Shale. Originally, the Tulip Beds was simply known as the "S7 locality", and would later receive its name due to the common occurrence of Siphusauctum gregarium fossils at the site. The locality is located on the northwestern portion of Mount Stephen, near the town of Field in the province of British Columbia. The site itself is around 4 km (2.5 mi) southwest of the younger Walcott Quarry locality, which itself is located on Fossil Ridge. The beds extend for at most 150 meters (492.2 feet), with typical height of around 3-12 meters (9-12 feet) tall along the mountainside. The base of the Tulip Beds occurs on top of the larger Yoho River Limestone Member, making it one of the oldest localities of the Burgess Shale. Fossils from the locality are known from two separate outcrops: an in situ quarry nicknamed "Above Campsite", and multiple talus deposits nicknamed the "Talus Site". These two sites are around 0.2 km (0.12 mi) apart, and show the characteristic mudstone, limestone, and concretions known from the Campsite Cliff Shale Member. The exact age of the member is thought to belong to the third series of the fifth stage of the Cambrian, around 508 million years ago, as evidenced by the presence of the Bathyuriscus-Elrathina Zone within the member.
Paleoenvironment The exact location of the Tulip Beds compared to the base of the Cathedral escarpment is thought to be more distal compared to the majority of the other Burgess Shale localities, such as Marble Canyon and the Walcott quarry. This is thought due to the relative distance of Mount Stephen compared to the escarpment, which is around 1,500 meters (4921.3 feet) away from the mountains northeastern portion. The ecosystem would've sat In gloomy water, near, or in the Mesopelagic zone, similarly to most of the other nearby localities. The majority of the fauna of the Tulip Beds include sessile taxa, notably Siphusauctum gregarium, which is known from around 1,133 specimens alone from the locality. Alongside S. gregarium, the sessile taxa mostly include suspension feeding organisms. The fauna includes taxa common in other Burgess Shale localities, and some which are only found at the Tulip Beds.
Arthropoda A wide variety of total-group (including hymenocarines and megacheirans) and stem-group arthropods (including radiodonts) are known from the Tulip Beds. ArthropodsGenusPhylumHigher taxonNotesImagesCaryosyntripsStem-group ArthropodaNot applicableAn enigmatic panarthropod that is characterized by a pair of forward facing frontal appendages. Originally classified as a problematic radiodont, its true taxonomic placement remains a point of contention. Its name literally translates to "nutcracker", due to the proposed movement of its appendages during prey capture.AnomalocarisStem-group ArthropodaRadiodontaThe largest radiodont from the Burgess shale, and the ecosystem's apex predator. This radiodont is known from hundreds of articulated frontal appendages in the Tulip Beds, often in large clusters, suggesting the area represented a mass molting site for this arthropod relative.PeytoiaStem-group ArthropodaRadiodontaA moderately rare peytoiid radiodont, often known from articulated frontal appendages, also found within the Walcott quarry. Originally named as a jellyfish due to the structure of its mouthparts, but was later recognized as a radiodont.HurdiaStem-group ArthropodaRadiodontaA common peytoiid known from carapace elements and frontal appendages in the Tulip Beds. Occasionally found in clusters, similarly to Anomalocaris.AmplectobeluaStem-group ArthropodaRadiodontaA member of the amplectobeluidae family, mainly known from the older Maotianshan Shales in China, however, the species Amplectobelua stephenensis is known from the Burgess Shale. This species is recognizable due to the massive distal endite on its frontal appendages, giving them an almost claw-like appearance.IsoxysArthropodaOrder IsoxyidaA very common bivalved arthropod that occupied a nektonic niche. Known for its cosmopolitan distribution in various other sites. Various species are known from the Burgess Shale alone.MarrellaArthropodaOrder MarrellomorphaOne of the most common organisms of the Burgess Shale, with over 25,000 specimens having been recorded, this small marrellomorphid arthropod is known from a majority of the sites localities, including the Tulip Beds. It most likely lived a mainly nektonic lifestyle, with its swimming appendages used in a backstroke motion, and its large spines potentially acting as stabilizers.PerspicarisArthropodaOrder HymenocarinaA hymenocarine arthropod known from two named species from the Burgess Shale; P. dictynna and P. recondita, which differ in maximum size (66 millimetres (2.6 in) in P. recondita vs 29 millimetres (1.1 in) in P. dictynna), as well as proportions of the tail.NereocarisArthropodaOrder HymenocarinaA large hymenocarine, known also from the Collins Quarry, and is known from two species, N. exilis and N. briggsi. It possessed an elongated trunk region, an enlarged carapace, and a set of three eyes (two stalked eyes, and one median eye).BranchiocarisArthropodaOrder HymenocarinaA hymenocarine that had a pair of short segmented tapered antennules with at least 20 segments, as well as a pair of claw-like appendages. Also possibly known from deposits in China and Utah.TuzoiaArthropodaOrder HymenocarinaA genus of large hymenocarine, and one of the largest known "bivalved arthropods" in the fossil record. Known from a variety of other deposits in North America, Australia, China, Europe and Siberia. It was most likely a nekto-benthic animal, swimming close too the seafloor. However, it is possible it could've been capable of walking on the seafloor as well.SidneyiaArthropoda(unranked) ArtiopodaSidneyia was a large 13 centimeter (5.1 in) long predatory artiopod that most likely was a durophagous predator, due to young trilobites, hyoliths, and brachiopods being commonly found as stomach contents. Other species are known from earlier deposits in China.NaraoiaArthropoda(unranked) ArtiopodA common nektaspid artiopod, and is characterized by a large alimentary system and sideways oriented antennas. Sediments present in the gut of Naraoia suggest that it may have been a deposit feeder, eating large amounts of soil while looking for soft bodied prey.OlenoidesArthropoda(unranked) ArtiopodOne of the more well known trilobites from the shale, with more than 213 specimens having been recorded, Olenoides is also known from several Cambrian sites across the northern hemisphere. This trilobite was likely a benthic generalist, feeding on a wide variety of prey items.BathyuriscusArthropoda(unranked) ArtiopodA member of the Dolichometopidae family, this trilobite was a nekto-benthic predator, and is an important stratigraphic marker for the larger Campsite Cliff Shale Member. Its major characteristics are a large forward-reaching glabella, pleurae with very short spines, and a medium pygidium with well-impressed furrows.ElrathinaArthropoda(unranked) Artiopoda trilobite belonging to the ptychopariida that is especially abundant on fossil ridge, with about 25% of all trilobite fossils described belonging to this genusHanburiaArthropoda(unranked) ArtiopodaA trilobite possibly belonging to the family Dolichometopidae, and is also known from the Walcott Quarry.LeanchoiliaArthropodaOrder MegacheiraA megacheiran arthropod. Leanchoilia and its relatives are distinguished from other arthropods by their frontal appendages, which split into three flagella bearing podomeres, which was probably used as both sensory and raptorial structures.HabeliaArthropodaChelicerataWhile previously enigmatic, a 2017 redescription found that Habelia was a stem-group member of the Chelicerata subphylum. The species known from the Tulip Beds, Habelia? brevicauda has been questioned as to whether or not it belongs to this genus, or if its a new taxon.
Lobopodia Like with most other Burgess Shale localities, the lobopodians (worm-like panarthropods from which arthropods arose from) are rare within the Tulip Beds, with a handful of genera known. LobopodiansGenusPhylumHigher taxonNotesImagesHallucigeniaLobopodiaHallucigeniidaeA spined lobopodian of the Hallucigeniidae family, This genus is one of the more iconic taxa from the shale. The generic name reflects the type species' unusual appearance and eccentric history of study; when it was erected as a genus, H. sparsa was reconstructed as an enigmatic animal upside down and back to front.EntothyreosLobopodiaLuolishaniidaeA unique spined lobopodian of the Luolishaniidae family, and only found within the Tulip Beds. The most common lobopodian of the locality, this panarthropod was a suspension feeder, like most of the other members of its family. It is unique for possessing a large amount of sclerotization compared to other lobopodians, comparable to that of true arthropods.
Porifera Among the sessile taxa of the Tulip Beds, Poriferans (sea sponges) hold the highest diversity, with up to a dozen genera known.