Protastacus: Difference between revisions
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A crustacean of moderate size, Harbort (1905) noted that larger specimens of ''Protastacus'' are around {{convert|10|cm|abbr=on|in}} long.<ref name=":1" /> The [[carapace]] is smooth and subcylindrical in shape, with a deep cervical groove stretching across its surface. This groove first bends down the carapace sides, then bends forwards, down and forwards again to reach the front of the carapace. There are no postcervical or branchiocardiac grooves. Two keel-like projections are present lower on the sides, as well as a thorn-like structure at the front of either side at the "cheek" area. Though the ends of the [[Antenna (biology)|antennae]] are not preserved, their bases were enlarged.<ref name=":0" /> |
A crustacean of moderate size, Harbort (1905) noted that larger specimens of ''Protastacus'' are around {{convert|10|cm|abbr=on|in}} long.<ref name=":1" /> The [[carapace]] is smooth and subcylindrical in shape, with a deep cervical groove stretching across its surface. This groove first bends down the carapace sides, then bends forwards, down and forwards again to reach the front of the carapace. There are no postcervical or branchiocardiac grooves. Two keel-like projections are present lower on the sides, as well as a thorn-like structure at the front of either side at the "cheek" area. Though the ends of the [[Antenna (biology)|antennae]] are not preserved, their bases were enlarged.<ref name=":0" /> |
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The first three pair of [[pereiopod]]s end with [[Pincer (biology)|pincers]], with the frontmost pair being most greatly enlarged.<ref name=":2" /> The first segment of the [[abdomen]] is small, whereas the second to sixth segments are larger and around the same size. The [[Exoskeleton|exoskeletal]] parts of these segments are [[Lateral (anatomy)|laterally]] rounded and enlarged, giving the appearance that these segments are bulging at the bottom. Like the carapace, the covering of the abdomen is smooth. The [[telson]] has a subrectangular shape and the [[uropod]]s are large, with the [[exopod]]s being divided by a distinct suture known as the diaeresis.<ref name=":0" /><ref>{{Cite journal |last=Karasawa |first=Hiroaki |last2=Schweitzer |first2=Carrie E. |last3=Feldmann |first3=Rodney M. |date=2013-01-01 |title=Phylogeny and systematics of extant and extinct lobsters |url=https://academic.oup.com/jcb/article-lookup/doi/10.1163/1937240X-00002111 |journal=Journal of Crustacean Biology |language=en |volume=33 |issue=1 |pages=78–123 |doi=10.1163/1937240X-00002111 |issn=0278-0372|doi-access=free }}</ref> |
The first three pair of [[pereiopod]]s end with [[Pincer (biology)|pincers]], with the frontmost pair being most greatly enlarged.<ref name=":2" /> The first segment of the [[abdomen]] is small, whereas the second to sixth segments are larger and around the same size. The [[Exoskeleton|exoskeletal]] parts of these segments are [[Lateral (anatomy)|laterally]] rounded and enlarged, giving the appearance that these segments are bulging at the bottom. Like the carapace, the covering of the abdomen is smooth. The [[telson]] has a subrectangular shape and the [[uropod]]s are large, with the [[exopod]]s being divided by a distinct suture known as the diaeresis.<ref name=":0" /><ref name=":3">{{Cite journal |last=Karasawa |first=Hiroaki |last2=Schweitzer |first2=Carrie E. |last3=Feldmann |first3=Rodney M. |date=2013-01-01 |title=Phylogeny and systematics of extant and extinct lobsters |url=https://academic.oup.com/jcb/article-lookup/doi/10.1163/1937240X-00002111 |journal=Journal of Crustacean Biology |language=en |volume=33 |issue=1 |pages=78–123 |doi=10.1163/1937240X-00002111 |issn=0278-0372|doi-access=free }}</ref> |
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==Classification== |
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Although both ''Protastacus'' species were initially described as species of ''[[Astacus]]'', Albrecht (1983) recognized that they form a distinct genus belonging in a separate family from ''Astacus''. He named this family Protastacidae, assigning the two genera ''Protastacus'' and ''[[Pseudastacus]]'' into it, the former being the [[type genus]] of the family.<ref name=":2" /> In 1997, Tshudy and Babcock reassigned ''Pseudastacus'' to the family [[Chilenophoberidae]], leaving Protastacidae as a [[monotypic family]] with ''Protastacus'' as its only genus.<ref>{{Cite journal |last=Tshudy |first=D. |last2=Babcock |first2=L.E. |date=1997-01-01 |title=Morphology-based phylogenetic analysis of the clawed lobsters (family Nephropidae and the new family Chilenophoberidae) |url=https://academic.oup.com/jcb/article-lookup/doi/10.1163/193724097X00288 |journal=Journal of Crustacean Biology |language=en |volume=17 |issue=2 |pages=253–263 |doi=10.1163/193724097X00288 |issn=0278-0372}}</ref> |
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The phylogenetic placement of Protastacidae has been a subject of controversy. Shen ''et al.'' (2001) and Schram (2001) questioned the family's placement in Astacidea.<ref>{{Cite journal |last=Shen |first=Yanbin |last2=Schram |first2=Frederick R. |last3=Taylor |first3=Rod S. |date=2001-01-01 |title=Morphological variation in fossil crayfish of the Jehol biota, Liaoning Province, China and its texonomic discrimination |url=https://doi.org/10.1007/BF03183202 |journal=Chinese Science Bulletin |language=en |volume=46 |issue=1 |pages=26–33 |doi=10.1007/BF03183202 |issn=1861-9541}}</ref><ref>{{Cite journal |last=Schram |first=Frederick R. |date=2001 |editor-last=Paula |editor-first=José P. M. |editor2-last=Flores |editor2-first=Augusto A. V. |editor3-last=Fransen |editor3-first=Charles H. J. M. |title=Phylogeny of decapods: moving towards a consensus |url=https://link.springer.com/chapter/10.1007/978-94-017-0645-2_1 |journal=Advances in Decapod Crustacean Research |series=Developments in Hydrobiology |language=en |location=Dordrecht |publisher=Springer Netherlands |pages=1–20 |doi=10.1007/978-94-017-0645-2_1 |isbn=978-94-017-0645-2}}</ref> In 2003, Rode and Babcock found that ''Protastacus'' belonged to the family [[Astacidae]], making Protastacidae an invalid grouping.<ref>{{Cite journal |last=Rode |first=Alycia L. |last2=Babcock |first2=Loren E. |date=2003-01-01 |title=Phylogeny of Fossil and Extant Freshwater Crayfish and Some Closely Related Nephropid Lobsters |url=https://academic.oup.com/jcb/article-lookup/doi/10.1163/20021975-99990351 |journal=Journal of Crustacean Biology |language=en |volume=23 |issue=2 |pages=418–435 |doi=10.1163/20021975-99990351 |issn=0278-0372}}</ref> From 2009 to 2012, Protastacidae was commonly placed in the superfamily [[Nephropoidea]] as relatives to the lobster family [[Nephropidae]].<ref>{{Cite journal |last=De Grave |first=Sammy |last2=Pentcheff |first2=N. Dean |last3=Ahyong |first3=Shane T. |last4=Chan |first4=Tin-Yam |last5=Crandall |first5=Keith A. |last6=Dworschak |first6=Peter C. |last7=Felder |first7=Darryl L. |last8=Feldmann |first8=Rodney M. |last9=Fransen |first9=Charles H. J. M. |last10=Goulding |first10=Laura Y. D. |last11=Lemaitre |first11=Rafael |last12=Low |first12=Martyn E. Y. |last13=Martin |first13=Joel W. |last14=Ng |first14=Peter K. L. |last15=Schweitzer |first15=Carrie E. |date=2009 |title=A Classification of Living and Fossil Genera of Decapod Crustaceans |url=http://repository.si.edu/xmlui/handle/10088/8358 |journal=The Raffles Bulletin of Zoology Supplement |language=en-US |volume=21 |pages=1–109 |issn=0217-2445}}</ref><ref>{{Cite book |last=Schweitzer |first=Carrie |url=https://books.google.co.uk/books?hl=en&lr=&id=iu15DwAAQBAJ&oi=fnd&pg=PA1&dq=info:LIwb7mJESyUJ:scholar.google.com/&ots=FITrUWMr-t&sig=4ozKZHxhxp_NBOCH7kdJfG2C_9k&redir_esc=y#v=onepage&q&f=false |title=Systematic List of Fossil Decapod Crustacean Species |last2=Feldmann |first2=Rodney |last3=Garassino |first3=Alessandro |last4=Karasawa |first4=Hiroaki |last5=Schweigert |first5=Günter |date=2010-01-07 |publisher=BRILL |isbn=978-90-474-4126-7 |language=en}}</ref><ref>{{Cite book |last=Schram |first=Frederick |url=https://books.google.co.uk/books?hl=en&lr=&id=5nRDSTCPfhoC&oi=fnd&pg=PP4&dq=info:Ll5FBoSWyisJ:scholar.google.com/&ots=nC8ZS60_0w&sig=Z2AyJ88N4a8DeRx-feg1X3Vbj5Y&redir_esc=y#v=onepage&q&f=false |title=Treatise on Zoology - Anatomy, Taxonomy, Biology. The Crustacea, Volume 9 Part B: Decapoda: Astacidea P.P. (Enoplometopoidea, Nephropoidea), Glypheidea, Axiidea, Gebiidea, and Anomura |last2=Klein |first2=Carel von Vaupel |date=2012-03-20 |publisher=BRILL |isbn=978-90-04-17673-7 |language=en}}</ref> Analysis by Karasawa ''et al.'' (2013) found that Protastacidae contained only the genus ''Protastacus'' and belonged in a monotypic [[Superfamily (biology)|superfamily]] (Protastacoidea), which is a [[sister taxon]] to the clade containing [[Astacoidea]] and [[Parastacoidea]].<ref name=":3" /> |
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==References== |
==References== |
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Revision as of 20:42, 13 December 2023
| Protastacus Temporal range:
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|---|---|
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Astacidea |
| Superfamily: | †Protastacoidea Albrecht, 1983 |
| Family: | †Protastacidae Albrecht, 1983 |
| Genus: | †Protastacus Albrecht, 1983 |
| Type species | |
| †Astacus politus Schlüter, 1868
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| Species | |
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| Synonyms | |
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P. antiquus synonymy:
P. politus synonymy:
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Protastacus is an extinct genus of decapod crustaceans that lived during the early Cretaceous period. It is the only genus in the family Protastacidae, which in turn is the only family in the superfamily Protastacoidea.
Discovery and naming
Fossils of Protastacus have been described 115 years before the genus was established. In 1868, Schlüter erected the species Astacus politus based on remains found near Ochtrup, Germany, believing it represented an extinct species of the extant crayfish genus Astacus.[1] Later in 1905, Erich Harbort studies fossilized remains in clay ironstone geodes found north of Bückeberg, Germany and erects the species Astacus antiquus based on them. Harbort notes the similarity between A. politus and A. antiquus, and that the two species differ in the shape of the carapace and uropods. The specific name antiquus is Latin meaning "ancient".[2]
Albrecht (1983) is the first to recognize that the two aforementioned species do not actually belong to Astacus. He erects the genus Protastacus with A. politus as its type species and A. antiquus as an additional species. The two are thus renamed as Protastacus politus and Protastacus antiquus respectively.[3]
Description
A crustacean of moderate size, Harbort (1905) noted that larger specimens of Protastacus are around 10 cm (3.9 in) long.[2] The carapace is smooth and subcylindrical in shape, with a deep cervical groove stretching across its surface. This groove first bends down the carapace sides, then bends forwards, down and forwards again to reach the front of the carapace. There are no postcervical or branchiocardiac grooves. Two keel-like projections are present lower on the sides, as well as a thorn-like structure at the front of either side at the "cheek" area. Though the ends of the antennae are not preserved, their bases were enlarged.[1]
The first three pair of pereiopods end with pincers, with the frontmost pair being most greatly enlarged.[3] The first segment of the abdomen is small, whereas the second to sixth segments are larger and around the same size. The exoskeletal parts of these segments are laterally rounded and enlarged, giving the appearance that these segments are bulging at the bottom. Like the carapace, the covering of the abdomen is smooth. The telson has a subrectangular shape and the uropods are large, with the exopods being divided by a distinct suture known as the diaeresis.[1][4]
Classification
Although both Protastacus species were initially described as species of Astacus, Albrecht (1983) recognized that they form a distinct genus belonging in a separate family from Astacus. He named this family Protastacidae, assigning the two genera Protastacus and Pseudastacus into it, the former being the type genus of the family.[3] In 1997, Tshudy and Babcock reassigned Pseudastacus to the family Chilenophoberidae, leaving Protastacidae as a monotypic family with Protastacus as its only genus.[5]
The phylogenetic placement of Protastacidae has been a subject of controversy. Shen et al. (2001) and Schram (2001) questioned the family's placement in Astacidea.[6][7] In 2003, Rode and Babcock found that Protastacus belonged to the family Astacidae, making Protastacidae an invalid grouping.[8] From 2009 to 2012, Protastacidae was commonly placed in the superfamily Nephropoidea as relatives to the lobster family Nephropidae.[9][10][11] Analysis by Karasawa et al. (2013) found that Protastacidae contained only the genus Protastacus and belonged in a monotypic superfamily (Protastacoidea), which is a sister taxon to the clade containing Astacoidea and Parastacoidea.[4]
References
- ^ a b c von der Marck, W.; Schlüter, C. (1868). Neue fische und krebse aus der kreide von Westphalen (PDF). Stuttgart: Palaeontographica. pp. 269–305. OCLC 39999779.
- ^ a b Harbort, Erich (1905). "Die Fauna der Schaumburg-Lippe'schen Kreidemulde" (PDF). Abh. königl. preuss. geol. Landesanstalt. 45: 17–24.
- ^ a b c Albrecht, von Henning (1983). "Die Protastacidae n. fam., fossile Vorfahren der Flußkrebse?" (PDF). Neues Jahrbuch für Geologie und Paläontologie. Monatsberichte (1): 5–15.
- ^ a b Karasawa, Hiroaki; Schweitzer, Carrie E.; Feldmann, Rodney M. (2013-01-01). "Phylogeny and systematics of extant and extinct lobsters". Journal of Crustacean Biology. 33 (1): 78–123. doi:10.1163/1937240X-00002111. ISSN 0278-0372.
- ^ Tshudy, D.; Babcock, L.E. (1997-01-01). "Morphology-based phylogenetic analysis of the clawed lobsters (family Nephropidae and the new family Chilenophoberidae)". Journal of Crustacean Biology. 17 (2): 253–263. doi:10.1163/193724097X00288. ISSN 0278-0372.
- ^ Shen, Yanbin; Schram, Frederick R.; Taylor, Rod S. (2001-01-01). "Morphological variation in fossil crayfish of the Jehol biota, Liaoning Province, China and its texonomic discrimination". Chinese Science Bulletin. 46 (1): 26–33. doi:10.1007/BF03183202. ISSN 1861-9541.
- ^ Schram, Frederick R. (2001). Paula, José P. M.; Flores, Augusto A. V.; Fransen, Charles H. J. M. (eds.). "Phylogeny of decapods: moving towards a consensus". Advances in Decapod Crustacean Research. Developments in Hydrobiology. Dordrecht: Springer Netherlands: 1–20. doi:10.1007/978-94-017-0645-2_1. ISBN 978-94-017-0645-2.
- ^ Rode, Alycia L.; Babcock, Loren E. (2003-01-01). "Phylogeny of Fossil and Extant Freshwater Crayfish and Some Closely Related Nephropid Lobsters". Journal of Crustacean Biology. 23 (2): 418–435. doi:10.1163/20021975-99990351. ISSN 0278-0372.
- ^ De Grave, Sammy; Pentcheff, N. Dean; Ahyong, Shane T.; Chan, Tin-Yam; Crandall, Keith A.; Dworschak, Peter C.; Felder, Darryl L.; Feldmann, Rodney M.; Fransen, Charles H. J. M.; Goulding, Laura Y. D.; Lemaitre, Rafael; Low, Martyn E. Y.; Martin, Joel W.; Ng, Peter K. L.; Schweitzer, Carrie E. (2009). "A Classification of Living and Fossil Genera of Decapod Crustaceans". The Raffles Bulletin of Zoology Supplement. 21: 1–109. ISSN 0217-2445.
- ^ Schweitzer, Carrie; Feldmann, Rodney; Garassino, Alessandro; Karasawa, Hiroaki; Schweigert, Günter (2010-01-07). Systematic List of Fossil Decapod Crustacean Species. BRILL. ISBN 978-90-474-4126-7.
- ^ Schram, Frederick; Klein, Carel von Vaupel (2012-03-20). Treatise on Zoology - Anatomy, Taxonomy, Biology. The Crustacea, Volume 9 Part B: Decapoda: Astacidea P.P. (Enoplometopoidea, Nephropoidea), Glypheidea, Axiidea, Gebiidea, and Anomura. BRILL. ISBN 978-90-04-17673-7.
External links
Media related to Protastacus at Wikimedia Commons
