Houcaris Temporal range: | |
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Fossils of H. magnabasis (B) and H. saron (D) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Order: | † Radiodonta |
Genus: | † Houcaris Wu et al., 2021 |
Type species | |
Houcaris saron (Hou, Bergström, & Ahlberg, 1995) | |
Other species | |
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Houcaris is a possibly paraphyletic radiodont genus, tentatively assigned to either Amplectobeluidae, Anomalocarididae or Tamisiocarididae, known from Cambrian Series 2 of China and the United States. The type species is Houcaris saron which was originally described as a species of the related genus Anomalocaris . [1] Other possible species include H. magnabasis and H. consimilis. [2] [3] The genus Houcaris was established for the two species in 2021 and honors Hou Xianguang, who had discovered and named the type species Anomalocaris saron in 1995 along with his colleagues Jan Bergström and Per E. Ahlberg. [4]
H. saron, known from Maotianshan Shale in Yunnan, is first described in 1995 as Anomalocaris saron. [4] This species is only known from frontal appendages. There is a specimen (ELRC 20001) that is previously considered as whole body fossil of this species, [4] but later study shows that this specimen is not belonging to this species, and later given own genus Innovatiocaris . [5] [6] [7] Length of frontal appendage is up to at least 12 cm. [2] Sometimes considered to belong to family Anomalocarididae [8] [9] or Amplectobeluidae. [10] [11]
H.? magnabasis, known from Pioche Shale and Pyramid shale in Nevada, is originally described as Anomalocaris cf. saron in 2003, [12] and later named as Anomalocaris magnabasis in 2019. [1] This species is only known from frontal appendages and some partial fossils of oral cone (mouthpart) and flaps. [1] Largest estimated length of frontal appendage is 17.5 cm. [1] Sometimes considered to belong to family Anomalocarididae [8] [9] or Amplectobeluidae. [10] [11]
However, results from the phylogenetic analysis by McCall in 2023 suggest that H.? magnabasis does not form a monophyletic clade with other species of Houcaris, and that it is a sister taxon of the Amplectobeluidae. Thus, he tentatively referred to the species as Anomalocaris magnabasis, even though the results show that it also does not form a clade with known species of Anomalocaris. [3]
H.? consimilis is known from the Maotianshan Shales of South China and possibly the Latham Shale of California. [1] While this species was originally described within Ramskoeldia and a sister taxon of its type species (R. platyacantha), subsequent studies have rejected their monophyly. In 2022, this species was recovered as a basal member of the Tamisiocarididae close to H. saron by the describers of Innovatiocaris , and not monophyletic with R. platyacantha. [13] In 2023, on the basis of phylogenetic analysis and morphological comparison, McCall suggested that it does not form a monophyletic clade with R. platyacantha, but instead with H. saron, so he included this species within the genus as Houcaris consimilis. His results also consistently recover both species as a member of the Amplectobeluidae. [3] Based on their phylogenetic analysis from the 2024 study describing Shucaris and the first-known oral cone of H? consimilis, Wu and colleagues recovered H? consimilis as an amplectobeluid, but not as a sister taxon of R. platyacantha, and rejected the tamisiocaridid affinity. [14]
Dinocaridida is a proposed fossil taxon of basal arthropods, which flourished during the Cambrian period and survived up to Early Devonian. Characterized by a pair of frontal appendages and series of body flaps, the name of Dinocaridids refers to the suggested role of some of these members as the largest marine predators of their time. Dinocaridids are occasionally referred to as the 'AOPK group' by some literatures, as the group compose of Radiodonta, Opabiniidae, and the "gilled lobopodians" Pambdelurion and Kerygmachelidae. It is most likely paraphyletic, with Kerygmachelidae and Pambdelurion more basal than the clade compose of Opabiniidae, Radiodonta and other arthropods.
Anomalocaris is an extinct genus of radiodont, an order of early-diverging stem-group arthropods.
Peytoia is a genus of hurdiid radiodont, an early diverging order of stem-group arthropods, that lived in the Cambrian period, containing two species, Peytoia nathorsti from the Miaolingian of Canada and Peytoia infercambriensis from Poland, dating to Cambrian Stage 3. Its two frontal appendages had long bristle-like spines, it had no fan tail, and its short stalked eyes were behind its large head.
Amplectobelua is an extinct genus of late Early Cambrian amplectobeluid radiodont, a group of stem arthropods that mostly lived as free-swimming predators during the first half of the Paleozoic Era.
Anomalocarididae is an extinct family of Cambrian radiodonts, a group of stem-group arthropods.
Schinderhannes bartelsi is a species of hurdiid radiodont (anomalocaridid), known from one specimen from the Lower Devonian Hunsrück Slates. Its discovery was astonishing because the latest definitive radiodonts were known only from the Early Ordovician, at least 66 million years earlier than this taxon.
Radiodonta is an extinct order of stem-group arthropods that was successful worldwide during the Cambrian period. Radiodonts are distinguished by their distinctive frontal appendages, which are morphologically diverse and used for a variety of functions. Radiodonts included the earliest large predators known, but they also included sediment sifters and filter feeders. Some of the most famous species of radiodonts are the Cambrian taxa Anomalocaris canadensis, Hurdia victoria, Peytoia nathorsti, Titanokorys gainesi, Cambroraster falcatus and Amplectobelua symbrachiata. The later surviving members include the subfamily Aegirocassisinae from the Early Ordovician of Morocco and the Early Devonian member Schinderhannes bartelsi from Germany.
Hurdia is an extinct genus of hurdiid radiodont that lived 505 million years ago during the Cambrian Period. Fossils have been found in North America, China and the Czech Republic.
Cucumericrus ("cucumber-leg") is an extinct genus of stem-arthropod. The type and only species is Cucumericrus decoratus, with fossils discovered from the Maotianshan Shales of Yunnan, China.
Caryosyntrips ("nutcracker") is an extinct genus of stem-arthropod which known from Canada, United States and Spain during the middle Cambrian. It was first named by Allison C. Daley and Graham E. Budd in 2010, being the type species Caryosyntrips serratus.
Tamisiocarididae is a family of radiodonts, extinct marine animals related to arthropods, that bore finely-spined appendages that were presumably used in filter-feeding. When first discovered, the clade was named Cetiocaridae after a speculative evolution artwork, Bearded Ceticaris by John Meszaros, that depicted a hypothetical filter-feeding radiodont at a time before any were known to exist. However, the family name was not valid according to the International Code of Zoological Nomenclature, as no real genus named "Cetiocaris" exists, and in 2019 it was formally replaced by the name Tamisiocarididae, after the only valid genus of the clade at the time. The family is only known from Series 2 of the Cambrian, unlike other radiodont families, which persisted longer into the Cambrian. All known species would have lived in tropical or subtropical waters, suggesting a preference for warmer waters.
Amplectobeluidae is a clade of Cambrian radiodonts. It currently includes five definitive genera, Amplectobelua, Lyrarapax, Ramskoeldia, Guanshancaris and a currently unnamed genus from the lower Cambrian aged Sirius Passet site in Greenland. There is also a potential fifth genus, Houcaris, but that genus has become problematic in terms of its taxonomic placement.
Hurdiidae is an extinct cosmopolitan family of radiodonts, a group of stem-group arthropods, which lived during the Paleozoic Era. It is the most long-lived radiodont clade, lasting from the Cambrian period to the Devonian period.
Ramskoeldia is a genus of amplectobeluid radiodont described in 2018. It was the second genus of radiodont found to possess gnathobase-like structures and an atypical oral cone after Amplectobelua. The type species, Ramskoeldia platyacantha, was discovered in the Chengjiang biota of China, the home of numerous radiodontids such as Amplectobelua and Lyrarapax.
Kylinxia is a genus of extinct arthropod described in 2020. It was described from six specimens discovered in Yu'anshan Formation in southern China. The specimens are assigned to one species Kylinxia zhangi. Dated to 518 million years, the fossils falls under the Cambrian period. Announcing the discovery on 4 November 2020 at a press conference, Zeng Han of the Nanjing Institute of Geology and Paleontology, said that the animal "bridges the evolutionary gap from Anomalocaris to true arthropods and forms a key ‘missing link’ in the origin of arthropods," which was "predicted by Darwin’s evolutionary theory." The same day the formal description was published in Nature.
Laminacaris is a genus of extinct stem-group arthropods (Radiodonta) that lived during the Cambrian period. It is monotypic with a single species Laminacaris chimera, the fossil of which was described from the Chengjiang biota of China in 2018. Around the same time, two specimens that were similar or of the same species were discovered at the Kinzers Formation in Pennsylvania, USA. The first specimens from China were three frontal appendages, without the other body parts.
Innovatiocaris is a genus of radiodont of uncertain family from the early Cambrian Chengjiang Lagerstätte of Yunnan Province, China. The genus contains two named species, I. maotianshanensis, known from a nearly complete young individual measuring up to 15.2 cm (6.0 in) and isolated frontal appendages, and I.? multispiniformis, known from a complete frontal appendage.
Lenisicaris is a Cambrian anomalocaridid radiodont, known from the Maotianshan Shales of China and the Kinzers Formation of Pennsylvania.
Shucaris is a genus of radiodont of uncertain taxonomic placement from the Lower Cambrian Maotianshan Shales in Yunnan, South China. The type and only species is S. ankylosskelos, known from multiple specimens comprising frontal appendages, multiple endites, gnathobase‐like structures, a nearly complete body, a head carapace complex, and one body flap associated with setal blades.