Protopsephurus: Difference between revisions
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{{Speciesbox |
{{Speciesbox |
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| fossil_range = {{fossil_range|130.0|112.0|Early Cretaceous}} |
| fossil_range = {{fossil_range|130.0|112.0|Early Cretaceous}} |
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| image = Protopsephurus-Tianjin Natural History Museum.jpg |
| image = Protopsephurus-Tianjin Natural History Museum (cropped).jpg |
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| image_caption = Fossil of ''P''. ''liui'', [[Tianjin Natural History Museum]] |
| image_caption = Fossil of ''P''. ''liui'', [[Tianjin Natural History Museum]] |
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| taxon = Protopsephurus liui |
| taxon = Protopsephurus liui |
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'''''Protopsephurus''''' is an extinct genus of [[paddlefish]] |
'''''Protopsephurus''''' is an extinct [[genus (biology)|genus]] of [[paddlefish]] containing the single species ''Protopsephurus liui,'' known from the [[Yixian Formation|Yixian]], [[Jiufotang Formation|Jiufotang]] and [[Huajiying Formation|Huajiying formations]] in [[Liaoning]], northern [[China]] from the [[Barremian]] to [[Aptian]] ages of the [[Early Cretaceous]] period around 125-120 million years ago.<ref name="paleodb">{{cite web|url=http://paleodb.org/cgi-bin/bridge.pl?a=checkTaxonInfo&taxon_no=94911&is_real_user=1|title=''Protopsephurus liui''|publisher=Paleobiology Database|accessdate=June 24, 2011}}</ref><ref name="paddlefish">{{cite web|url=http://radis.doane.edu/paddlefish/pfishclass.asp|title=Paddlefish Classes|publisher=Paddlefish Bibliography|accessdate=June 24, 2011}}</ref> It is currently the oldest and most [[Basal (phylogenetics)|basal]] paddlefish known. |
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==Description== |
==Description== |
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The species is known from numerous specimens ranging up to about {{cvt|80|cm}} long. The snout is shorter than that in any other known paddlefish, and is more [[sturgeon]]-like. The morphology of the skull roof is also more archaic than any other paddlefish. The [[axial skeleton]] is poorly ossified. Like other extinct polyodontids, it also has tiny non-interlocking scales approximately 1 mm in diameter called [[Fish scale#Placoid scales|denticles]] that cover the trunk, which bear a fringe of spikes.<ref name=":0">{{Cite journal |last1=Grande |first1=Lance |last2=Jin |first2=Fan |last3=Yabumoto |first3=Yoshitaka |last4=Bemis |first4=William E. |date=2002-07-08 |title=Protopsephurus liui, a well-preserved primitive paddlefish (Acipenseriformes: Polyodontidae) from the Lower Cretaceous of China |url=https://doi.org/10.1671/0272-4634(2002)022[0209:PLAWPP]2.0.CO;2 |journal=Journal of Vertebrate Paleontology |volume=22 |issue=2 |pages=209–237 |doi=10.1671/0272-4634(2002)022[0209:PLAWPP]2.0.CO;2 |s2cid=86258128 |issn=0272-4634}}</ref>[[Image:Protopsephurus.png|thumb|250px|left|A reconstruction of ''Protopsephurus'' and ''[[Lycoptera]]'']] |
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The remains of 2 individuals that have been discovered in the Yixian Formation can be compared to living members of the Paddlefish family to show that very little has changed about them since the [[Early Cretaceous]]. Unlike other filter-feeding fish that have been discovered with many members but extremely fragmented remains, only two members of ''Protopsephurus'' have been discovered and nearly all the skeletal elements of this [[chondrostean]] [[ray-finned fish]] species have remained. {{cn|date=January 2020}} The [[Rostrum (anatomy)|rostrum]] is narrow and sword-like instead of broad and paddle-like, and its skin is smooth and scaleless. Its eyes are minimalized and poorly developed. It has a [[heterocercal]] tail, and the origin of their name comes from the belief that the paddlefish used their rostrum to excavate bottom substrate in order to find prey. |
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== Diet == |
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''Protopsephurus'' is thought to have been [[Piscivore|piscivorous]], feeding on smaller fish. One adult specimen of ''Protopsephurus'' has been observed with a specimen of ''[[Lycoptera]]'', the most common fish in the formation, preserved in its stomach. Piscivory is likely the ancestral ecology of paddlefish, with only the genus ''[[Polyodon]]'' making the transition to being [[Planktivore|planktivorous]] filter feeders.<ref name=":0" /> |
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''Protopsephurus'' is the largest known member of the [[Polyodontidae]]. Their sizes, due to lack of [[habitat loss]] and the lack of large [[freshwater]] predators, were able to rival and exceed the size of their living relatives [[Chinese Paddlefish]] (''Psephurus gladius'') and [[American Paddlefish]] (''Polyodon spathula''). The two specimens recovered by Lu in 1994 were measured and shown to have grown to 7 meters (23 feet), greater than the maximum size of present day [[Chinese Paddlefish]]. |
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==Paleobiology== |
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[[Image:Protopsephurus.png|thumb|250px|left|A reconstruction of ''Protopsephurus'' and ''[[Lycoptera]]'']] |
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''Protopsephurus'' was a nektobenthic carnivore, swimming along the bottoms of freshwater rivers and [[estuaries]], using their array of specialized [[gill rakers]] lining their gill basket to extract [[zooplankton]] and [[phytoplankton]] from the water, along with catching and eating smaller fish. Their most likely source of food was [[Ostracod]] (seed shrimp) that inhabited the bottoms of rivers and other planktivorous fish like the members of [[Lycoptera]]. Phases during the [[Yixian Formation]] were riddled with [[Limnic eruption]]s which caused freshwater lakes to be filled with massive amounts of phytoplankton and other diverse plantlife, increasing the amount of food available for them. The phytoplankton that bloomed from these river systems and drained into the ocean allowed the ''Protopsephurus'' to breed upstream via [[broadcast spawning]], giving their offspring a safe environment away from larger members and allowing them to reintegrate into the lakes that juveniles and adults inhabited. ''Protopsephurus'' did not only need to rely on the consumption of plankton, and had a body covered with sensory pores. These sensory pores allowed it to forage for zooplankton and identify their swimming and feeding habits. The most powerful of these electroreceptors were [[ampulla]] (hair cells), lined along their giant rostrum and allowed them to easily identify and locate their prey.<ref>[http://www.paleoglot.org/files/Wang&_99.pdf Vertebrate assemblages of the Jehol Biota in western Liaoning, China] Xiaolin Wang, Yuanqing Wang, Fan Jin 1 Xing Xu and Yuan Wang.</ref> |
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==Etymology== |
==Etymology== |
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Latest revision as of 12:19, 19 May 2024
| Protopsephurus Temporal range:
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| Fossil of P. liui, Tianjin Natural History Museum | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Acipenseriformes |
| Family: | Polyodontidae |
| Subfamily: | †Protopsephurinae |
| Genus: | †Protopsephurus Lu, 1994 |
| Species: | †P. liui
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| Binomial name | |
| †Protopsephurus liui Lu, 1994
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Protopsephurus is an extinct genus of paddlefish containing the single species Protopsephurus liui, known from the Yixian, Jiufotang and Huajiying formations in Liaoning, northern China from the Barremian to Aptian ages of the Early Cretaceous period around 125-120 million years ago.[1][2] It is currently the oldest and most basal paddlefish known.
Description[edit]
The species is known from numerous specimens ranging up to about 80 cm (31 in) long. The snout is shorter than that in any other known paddlefish, and is more sturgeon-like. The morphology of the skull roof is also more archaic than any other paddlefish. The axial skeleton is poorly ossified. Like other extinct polyodontids, it also has tiny non-interlocking scales approximately 1 mm in diameter called denticles that cover the trunk, which bear a fringe of spikes.[3]
Diet[edit]
Protopsephurus is thought to have been piscivorous, feeding on smaller fish. One adult specimen of Protopsephurus has been observed with a specimen of Lycoptera, the most common fish in the formation, preserved in its stomach. Piscivory is likely the ancestral ecology of paddlefish, with only the genus Polyodon making the transition to being planktivorous filter feeders.[3]
Etymology[edit]
The name comes from Ancient Greek words "protos" (first) and "psepharos" (cloudy/gloomy one). However the name also translates to "first pebble bearer" from the words "psephus" (pebble) and "phorus" (holder), commonly spelled as "psephurus". Eduard von Martens, a German zoologist and the first person to describe its living relative the Chinese Paddlefish, did not provide a definition on the meaning of the binomial name.
See also[edit]
References[edit]
- ^ "Protopsephurus liui". Paleobiology Database. Retrieved June 24, 2011.
- ^ "Paddlefish Classes". Paddlefish Bibliography. Retrieved June 24, 2011.
- ^ a b Grande, Lance; Jin, Fan; Yabumoto, Yoshitaka; Bemis, William E. (2002-07-08). "Protopsephurus liui, a well-preserved primitive paddlefish (Acipenseriformes: Polyodontidae) from the Lower Cretaceous of China". Journal of Vertebrate Paleontology. 22 (2): 209–237. doi:10.1671/0272-4634(2002)022[0209:PLAWPP]2.0.CO;2. ISSN 0272-4634. S2CID 86258128.
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