| 词条 | Kirengellida |
| 释义 |
| fossil_range = {{fossil range|Late Cambrian|Mid Ordovician}} | taxon = Kirengellidae | authority= Rozov 1975 }} The Kirengellids are a group of problematic Cambrian fossil shells of marine organisms. The shells bear a number of paired muscle scars on the inner surface of the valve. These fossils have conventionally been regarded as monoplacophoran molluscs, and possibly ancestral to gastropods or cephalopods.[1] They were presumed to be exogastric on the presumption that their larger muscle scars were anterior,[2][3] but it may be dangerous to compare these scars with molluscan musculature.[4] In any case, they coiled in the opposite direction to Romaniella.[4] However, their calcitic shells, the position of the muscle scars, and putative association with secondary shell elements, make a brachiopod affinity possible, by analogy with the mobergellans: a group of phosphatic shells from the same time period, with a similar set of muscle scars.[4] There is also strong similarity to the contemporary brachiopod group, the Craniopsids. In the case of this diagnosis, a simple lophophore apparatus is postulated to sit between the muscle scars and the edges of the shell.[4] Included taxaAfter [4]{{rp|fig. 5}}
References1. ^e.g. {{citation| first1 = E. L.| last2 = Flower| first2 = R. H.| first3 = G. F. | title = The bearing of the new Late Cambrian monoplacophoran genus Knightoconus upon the origin of the Cephalopoda | journal = Lethaia| last3 = Webers | volume = 6 | issue = 3 | pages = 275–309 | year = 1973| last1 = Yochelson | doi = 10.1111/j.1502-3931.1973.tb01199.x}} 2. ^{{cite journal| author1 = Yochelson, E.L.| title = An alternative approach to the interpretation of the phylogeny of ancient mollusks| url = https://archive.org/details/malacologia171978inst| journal = Malacologia| volume = 17| issue = 2| pages = 165–191| year = 1978}} 3. ^{{cite book| author = Yochelson, E.L| author2= Webers, G.F.| year =2006| title = A restudy of the Late Cambrian Molluscan fauna of Berkey (1898) from Taylors Falls, Minnesota| journal = Minnesota Geological Survey Report of Investigations | volume = 64| pages = 60| url = http://conservancy.umn.edu/bitstream/58939/1/RI64%5B1%5D.pdf}} 4. ^1 2 3 4 {{cite journal|title=BRACHIOPOD IDENTITY OF THE ALLEGED MONOPLACOPHORAN ANCESTORS OF CEPHALOPODS|author=Dzik, Jerzy|journal=Malacologia |volume=52 |issue=1 |pages=97–113 |year=2010|url=http://www.paleo.pan.pl/people/Dzik/Publications/Angarella.pdf}}
1 : Cambrian life |
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