Calamosaurus

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Calamosaurus
Temporal range: Early Cretaceous, Barremian
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Calamosaurus.jpg
Cervical vertebra of Calamosaurus foxi
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Tyrannoraptora
Superfamily:† Tyrannosauroidea (?)
Genus:† Calamosaurus
Lydekker, 1891
Species:
†C. foxi
Binomial name
†Calamosaurus foxi
(Lydekker, 1889 [originally Calamospondylus ])
Synonyms

Calamosaurus (meaning "reed lizard") is a genus of small theropod dinosaur, possibly a tyrannosauroid, from the Early Cretaceous of the Isle of Wight, England. It is based on two cervical vertebrae (NHMUK PV R 901), collected by Reverend William Fox. These fossils come from sedimentary rocks of the Wessex Formation and are Barremian in age. The type species of Calamosaurus, named Calamospondylus foxi by Richard Lydekker, was named in honour of Fox. Calamospondylus , however, was a preoccupied name, forcing Lydekker to change the genus name to Calamosaurus. This has subsequently led to immense confusion, with some authors believing the two genera to be synonymous. The systematic position of Calamosaurus within theropods has been controversial, and placements within Compsognathidae and Ornithomimosauria have been suggested. More recently, Darren Naish suggested that it was a member of the tyrannosaur lineage.

Contents

Discovery and naming

The type specimen, NHMUK PV R 901, consisting of two articulated cervical (neck) vertebrae, [1] was part of the "Fox collection", a collection of fossils collected by the Rev. William Fox which were given to the Natural History Museum in London on his death. When cataloguing the Fox collection, Richard Lydekker came across these bones and named them Calamospondylus foxi. The name derives from the Ancient Greek kalamos ('reed') and spondylus ('vertebra') and hints at the slender and lightweight build of the vertebrae. [2] [3] Unbeknownst to Lydekker, the name Calamospondylus had already been coined in 1866 (by Reverend Fox himself, the very man honored in Lydekker's species name). [4] Upon realising his mistake, Lydekker promptly renamed it, creating the new combination Calamosaurus foxi (from the Latin sauros, "lizard") in 1891. [5]

Possible second specimen

In the same work, Lydekker provisionally assigned the right tibia NHMUK R.186, which was discovered by William D. Fox in 1865 or 1866, to Calamosaurus; this specimen was later identified as being a basal or nonspecific coelurosaur, [6] [7] [8] possibly a compsognathid, [2] and has more recently been referred to the clade Ornithomimosauria. [9] [10] Darren Naish noted in 2011 that there is "no firm basis" for the assignment of NHMUK R.186 to Calamosaurus. [1]

Classification

The initial mistake made by Lydekker has led to immense confusion regarding the validity of Calamosaurus. Many authors have regarded it as a junior synonym of Calamospondylus, [11] [12] [13] despite the lack of overlapping material. [2] Beyond that, it was subsequently regarded by Lydekker as a synonym of Aristosuchus. [14] Some authors have opted to relegate Calamosaurus to the status of a nomen dubium due to its fragmentary condition and ambiguous taxonomy, [2] [15] [16] although this view is not universal. In 2011, Darren Naish supported the validity of the genus, and noted similarities with the Chinese taxon Dilong paradoxus that are indicative of a basal position within Tyrannosauroidea, though did caution against the assignment of further remains to the genus considering its fragmentary state. [1]

Description

Illustration of one of the holotype vertebrae Calamosaurus vertebra.jpg
Illustration of one of the holotype vertebrae

In 2001, Darren Naish, Steve Hutt, and David Martill estimated that Calamosaurus may have reached a body length of 3.5 m (11 ft). Initially, they noted that the fusion of the neural arches to the vertebral centra (the main body of each vertebra) suggests that it was fully grown at the time of its death; [2] however, in a 2011 work, Naish noted that the neurocentral sutures of the specimen were not fully closed, suggesting that it had not reached full skeletal maturity. He did, however, support the initial size estimate for the specimen. [1] Both of the holotype Calamospondylus cervical (neck) vertebrae are about 40 mm (1.6 in) in length. They are opisthocoelous, meaning that they are convex anteriorly (towards the front), and concave posteriorly (towards the rear), with offset articular facets, similar to those of Dilong. [1] The cervical vertebrae were at one point interpreted as lacking epipophyses entirely, suggesting a small, lightly built head; [2] whilst they are indeed present, they are very strongly reduced. [1]

Palaeoecology

A selection of Wessex Formation dinosaurs. On the left is Iguanodon. In the foreground is a group of Hypsilophodon being pursued by an Eotyrannus. In the right background is a Neovenator. In the midground is a pair of basal ornithomimosaurs. Wessex Formation dinosaurs.jpg
A selection of Wessex Formation dinosaurs. On the left is Iguanodon. In the foreground is a group of Hypsilophodon being pursued by an Eotyrannus. In the right background is a Neovenator. In the midground is a pair of basal ornithomimosaurs.

The holotype of Thecocoelurus heralds from the Wessex Formation. [17] Sedimentological data suggests that the depositional environment of the Wessex Formation was a floodplain intersected by fluvial (river) and lacustrine (lake) deposits. Water levels likely varied throughout the year, [18] due to there being more evaporation than precipitation, though precipitation was regardless quite high. The Wessex seems to have regularly experienced extreme storms [19] and periodic flood events, resulting in debris flows which would have deposited dead organisms in ponds. [20] Burned plant and insect material and fusain suggests that the environment experienced frequent wildfires, stifling for the most part the dense growth of gymnosperms. [18] [20] Much of the flora of the formed of low ground cover, consisting primarily of pteridophytes, with occasional stands of conifers, cycads and the tree fern Tempskya . [18] Most vertebrate material from the Wessex Formation originates from plant debris beds, resulting from the aforementioned flooding events. [20]

Aside from Thecocoelurus, the dinosaur fauna of the Isle of Wight includes the theropods Aristosuchus , Calamospondylus , Ceratosuchops , Eotyrannus , Neovenator , Ornithodesmus , Riparovenator, Thecocoelurus, and Yaverlandia , the sauropods Chondrosteosaurus , Eucamerotus and Ornithopsis , [21] [22] the thyreophorans Polacanthus [22] and Vectipelta , [23] and the ornithopods Brighstoneus , [24] Comptonatus , [25] Hypsilophodon , Iguanodon , [22] Mantellisaurus , [26] Valdosaurus [21] [22] and Vectidromeus. [27] The pterosaur fauna of the Wessex Formation consists of Coloborhynchus , Caulkicephalus , Istiodactylus , [28] Vectidraco , [29] and Wightia ; [30] multiple unnamed pterosaur taxa, including a ctenochasmatid, are also known. [28] Neosuchian crocodyliforms include Bernissartia , Koumpiodontosuchus [31] and Vectisuchus . [32] Limited evidence exists of elasmosaurids and leptocleidid plesiosaurs. [33] The mammal fauna of the Wessex Formation includes the multituberculate Eobataar [34] and the spalacotheriid Yaverlestes . [35] Albanerpetontid amphibians are represented by Wesserpeton . [36] The fish fauna of the Wessex Formation, both bony and cartilaginous, is extensive, including hybodontiform and modern sharks (Selachii), pycnodontiforms, Lepidotes and Scheenstia . [37] Invertebrates are represented by an assortment of non-biting midges, [38] hymenopterans (wasps) including multiple parasitoid taxa, [39] coleopterans (beetles), the avicularoid spider Cretamygale , [40] and the ostracod Cypridea. [41]

References

  1. 1 2 3 4 5 6 Naish, D. 2011. Theropod dinosaurs. In Batten, D. J. (ed.) English Wealden Fossils. The Palaeontological Association (London), pp. 526–559.
  2. 1 2 3 4 5 6 Naish, D., Hutt, S., and Martill, D.M. (2001). Saurischian dinosaurs 2: theropods. In: Martill, D.M., and Naish, D. (eds.). Dinosaurs of the Isle of Wight. The Palaeontological Association:London, 242-309. ISBN   0-901702-72-2
  3. ↑ Creisler, Ben (July 7, 2003). "Dinosauria Translation and Pronunciation Guide C". Dinosauria On-Line. Archived from the original on January 5, 2010. Retrieved September 11, 2007.
  4. ↑ Fox, W.D. in Anonymous. (1866) Another Wealden reptile. Athenaeum2014:740.
  5. ↑ Lydekker. R. (1891). On certain ornithosaurian and dinosaurian remains. Quarterly Journal of the Geological Society of London47:41-44.
  6. ↑ Norman, D.B., (1990). Problematic Theropoda: “Coelurosaurs”. In: Weishampel, D.B., Dodson, P., Osmolska, H. (eds.). The Dinosauria. Berkeley, University of California Press, 280-305.
  7. ↑ Kirkland, J.I.; Britt, B.B.; Whittle, C.H.; Madsen, S.K.; Burge, D.L. (1998). "A small coelurosaurian theropod from the Yellow Cat Member of the Cedar Mountain Formation (Lower Cretaceous, Barremian) of eastern Utah". New Mexico Museum of Natural History and Science Bulletin. 14: 239–248.
  8. ↑ Long, J.A. and Molnar, R.E. (1998). "A new Jurassic theropod dinosaur from Western Australia". Records of the Western Australian Museum 19 (1): 221-229
  9. ↑ Welles, S.P., Long, R.A., (1974). The tarsus of theropod dinosaurs. Annals of the South African Museum, 64, 191-218.
  10. ↑ R. Allain, R. Vullo, J. Le loeuff & J.-F. Tournepiche (2014) European ornithomimosaurs (Dinosauria, Theropoda): an undetected record. Geologica Acta12: (2) (advance online publication) June 2014.
  11. ↑ Swinton, W.E. (1936). The dinosaurs of the Isle of Wight. Proceedings of the Geologists' Association47(3):204-220.
  12. ↑ Romer, A.S. (1956). Osteology of the Reptiles. University of Chicago Press:Chicago, 1-772. ISBN   0-89464-985-X
  13. ↑ Steel, R. (1970). Part 14. Saurischia. Handbuch der Paläoherpetologie/Encyclopedia of Paleoherpetology. Part 14. Gustav Fischer Verlag:Stuttgart, 1-87.
  14. ↑ Lydekker, R. (1891). "On certain Ornithosaurian and Dinosaurian Remains" . Quarterly Journal of the Geological Society. 47 (1–4): 41–44. doi:10.1144/gsl.jgs.1891.047.01-04.06. ISSN   0370-291X.
  15. ↑ Norman, D.B. (1990). Problematic theropoda: "coelurosaurs". In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). The Dinosauria. University of California Press:Berkeley, 280-305. ISBN   0-520-06727-4.
  16. ↑ Holtz Jr., T.R., Molnar, R.E., and Currie, P.J. (2004). Basal Tetanurae. In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). The Dinosauria (second edition). University of California Press:Berkeley, 71-110. ISBN   0-520-24209-2.
  17. ↑ Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Cretaceous, Europe)". In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 556-563. ISBN   0-520-24209-2.
  18. 1 2 3 Insole, Allan N.; Hutt, Stephen (1994). "The palaeoecology of the dinosaurs of the Wessex Formation (Wealden Group, Early Cretaceous), Isle of Wight, Southern England" . Zoological Journal of the Linnean Society. 112 (1–2): 197–215. doi:10.1111/j.1096-3642.1994.tb00318.x.
  19. ↑ Marsden, Marie K.; Gunn, Joshua; Maidment, Susannah C. R.; Nichols, Gary; Wheeley, James R.; Russell, Catherine E.; Boomer, Ian; Stukins, Stephen; Butler, Richard J. (2025-01-06). "Palaeoenvironment and taphonomy of the Hypsilophodon Bed, Lower Cretaceous Wessex Formation, Isle of Wight". Journal of the Geological Society. 182 (1): jgs2024–046. Bibcode:2025JGSoc.182...46M. doi: 10.1144/jgs2024-046 .
  20. 1 2 3 Pond, Stuart; Strachan, Sarah-Jane; Raven, Thomas J.; Simpson, Martin I.; Morgan, Kirsty; Maidment, Susannah C. R. (2023). "Vectipelta barretti , a new ankylosaurian dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, UK" . Journal of Systematic Palaeontology. 21 (1). Bibcode:2023JSPal..2110577P. doi:10.1080/14772019.2023.2210577. ISSN   1477-2019.
  21. 1 2 Barker, C.T.; Hone, D.; Naish, D.; Cau, A.; Lockwood, J.; Foster, B.; Clarkin, C.; Schneider, P.; Gostling, N. (2021). "New spinosaurids from the Wessex Formation (Early Cretaceous, UK) and the European origins of Spinosauridae". Scientific Reports. 11 (1): 19340. Bibcode:2021NatSR..1119340B. doi:10.1038/s41598-021-97870-8. PMC   8481559 . PMID   34588472.
  22. 1 2 3 4 Martill, D. M.; Hutt, S. (1996). "Possible baryonychid dinosaur teeth from the Wessex Formation (Lower Cretaceous, Barremian) of the Isle of Wight, England". Proceedings of the Geologists' Association. 107 (2): 81–84. Bibcode:1996PrGA..107...81M. doi:10.1016/S0016-7878(96)80001-0.
  23. ↑ Pond, Stuart; Strachan, Sarah-Jane; Raven, Thomas J.; Simpson, Martin I.; Morgan, Kirsty; Maidment, Susannah C. R. (2023-01-01). "Vectipelta barretti, a new ankylosaurian dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, UK" . Journal of Systematic Palaeontology. 21 (1). Bibcode:2023JSPal..2110577P. doi:10.1080/14772019.2023.2210577. ISSN   1477-2019. S2CID   259393929.
  24. ↑ Lockwood, Jeremy A. F.; Martill, David M.; Maidment, Susannah C. R. (2021-11-10). "A new hadrosauriform dinosaur from the Wessex Formation, Wealden Group (Early Cretaceous), of the Isle of Wight, southern England". Journal of Systematic Palaeontology. 19 (12): 847–888. Bibcode:2021JSPal..19..847L. doi: 10.1080/14772019.2021.1978005 . ISSN   1477-2019. S2CID   244067410.
  25. ↑ Lockwood, Jeremy A. F.; Martill, David M.; Maidment, Susannah C. R. (2024-12-31). "Comptonatus chasei, a new iguanodontian dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, southern England". Journal of Systematic Palaeontology . 22 (1). Bibcode:2024JSPal..2246573L. doi: 10.1080/14772019.2024.2346573 . ISSN   1477-2019.
  26. ↑ Carpenter, K. & Ishida, Y. (2010). "Early and "Middle" Cretaceous Iguanodonts in Time and Space". Journal of Iberian Geology . 36 (2): 145–164. doi: 10.5209/rev_JIGE.2010.v36.n2.3 .
  27. ↑ Longrich, Nicholas R.; Martill, David M.; Munt, Martin; Green, Mick; Penn, Mark; Smith, Shaun (2024-02-01). "Vectidromeus insularis, a new hypsilophodontid dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, England" . Cretaceous Research. 154 105707. Bibcode:2024CrRes.15405707L. doi:10.1016/j.cretres.2023.105707. ISSN   0195-6671.
  28. 1 2 Martill, David M.; Coram, Robert A. (2020-08-01). "Additional evidence for very large wing-span pterosaurs in the Wessex Formation (Early Cretaceous, Barremian) of southern England" . Proceedings of the Geologists' Association. 131 (3): 293–300. Bibcode:2020PrGA..131..293M. doi:10.1016/j.pgeola.2019.05.002. ISSN   0016-7878.
  29. ↑ Naish, D.; Simpson, M.; Dyke, G. (2013). Farke, Andrew A (ed.). "A New Small-Bodied Azhdarchoid Pterosaur from the Lower Cretaceous of England and Its Implications for Pterosaur Anatomy, Diversity and Phylogeny". PLOS ONE. 8 (3) e58451. Bibcode:2013PLoSO...858451N. doi: 10.1371/journal.pone.0058451 . PMC   3601094 . PMID   23526986.
  30. ↑ Martill, David M.; Green, Mick; Smith, Roy E.; Jacobs, Megan L.; Winch, John (2020-09-01). "First tapejarid pterosaur from the Wessex Formation (Wealden Group: Lower Cretaceous, Barremian) of the United Kingdom" . Cretaceous Research. 113 104487. Bibcode:2020CrRes.11304487M. doi:10.1016/j.cretres.2020.104487. ISSN   0195-6671.
  31. ↑ Sweetman, Steven; Pedreira-Segade, Ulysse; Vidovic, Steven (2014). "A new bernissartiid crocodyliform from the Lower Cretaceous Wessex Formation (Wealden Group, Barremian) of the Isle of Wight, southern England". Acta Palaeontologica Polonica. doi:10.4202/app.00038.2013. ISSN   0567-7920.
  32. ↑ Buffetaut, Eric; Hutt, Stephen (1980-07-31). "Vectisuchus leptognathus, n. g. n. sp., a slender-snouted goniopholid crocodilian from the Wealden of the Isle of Wight" . Neues Jahrbuch für Geologie und Paläontologie - Monatshefte (7): 385–390. doi:10.1127/njgpm/1980/1980/385.
  33. ↑ Kear, Benjamin P.; Barrett, Paul M. (2011-03-01). "Reassessment of the Lower Cretaceous (Barremian) pliosauroid Leptocleidus superstes Andrews, 1922 and other plesiosaur remains from the nonmarine Wealden succession of southern England" . Zoological Journal of the Linnean Society. 161 (3): 663–691. doi:10.1111/j.1096-3642.2010.00648.x. ISSN   0024-4082.
  34. ↑ Sweetman, Steven C. (2009). "A New Species of the Plagiaulacoid Multituberculate Mammal Eobaatar from the Early Cretaceous of Southern Britain". Acta Palaeontologica Polonica. 54 (3): 373–384. doi: 10.4202/app.2008.0003 . ISSN   0567-7920.
  35. ↑ Sweetman, Steven C. (2008). "A Spalacolestine Spalacotheriid (mammalia, Trechnotheria) from the Early Cretaceous (barremian) of Southern England and Its Bearing on Spalacotheriid Evolution" . Palaeontology. 51 (6): 1367–1385. Bibcode:2008Palgy..51.1367S. doi:10.1111/j.1475-4983.2008.00816.x. ISSN   1475-4983.
  36. ↑ Sweetman, Steven; Gardner, James (2013-06-01). "A new albanerpetontid amphibian from the Early Cretaceous (Barremian) Wessex Formation of the Isle of Wight, southern England". Acta Palaeontologica Polonica. 58 (2): 295–324. doi: 10.4202/app.2011.0109 . ISSN   0567-7920.
  37. ↑ Sweetman, Steven C.; Goedert, Jean; Martill, David M. (2014-11-01). "A preliminary account of the fishes of the Lower Cretaceous Wessex Formation (Wealden Group, Barremian) of the Isle of Wight, southern England". Biological Journal of the Linnean Society. 113 (3): 872–896. doi:10.1111/bij.12369. ISSN   0024-4066.
  38. ↑ Baranov, Viktor; Giłka, Wojciech; Zakrzewska, Marta; Jarzembowski, Edmund (2019-03-01). "New non-biting midges (Diptera: Chironomidae) from Lower Cretaceous Wealden amber of the Isle of Wight (UK)" . Cretaceous Research. 95: 138–145. Bibcode:2019CrRes..95..138B. doi:10.1016/j.cretres.2018.11.012. ISSN   0195-6671.
  39. ↑ Perkovsky, Evgeny E.; Olmi, Massimo; Müller, Patrick; Guglielmino, Adalgisa; Jarzembowski, Edmund A.; Capradossi, Leonardo; Rasnitsyn, Alexandr P. (2021-05-01). "A review of the fossil Embolemidae (Hymenoptera: Chrysidoidea), with description of seven new species and history of the family" . Cretaceous Research. 121 104708. Bibcode:2021CrRes.12104708P. doi:10.1016/j.cretres.2020.104708. ISSN   0195-6671.
  40. ↑ Selden, Paul A. (2002). "First British Mesozoic Spider, From Cretaceous Amber Of The Isle Of Wight, Southern England". Palaeontology. 45 (5): 973–983. Bibcode:2002Palgy..45..973S. doi:10.1111/1475-4983.00271. hdl: 1808/8357 . ISSN   1475-4983.
  41. ↑ Penn, Simon J.; Sweetman, Steven C. (2023-03-01). "Microvertebrate-rich gutter casts from the basal Wessex Formation (Wealden Group, Lower Cretaceous) of Dungy Head, Dorset: Insights into the palaeoecology and palaeoenvironment of a non-marine wetland" . Cretaceous Research. 143 105397. Bibcode:2023CrRes.14305397P. doi:10.1016/j.cretres.2022.105397. ISSN   0195-6671.
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