| 词条 | Balticeras |
| 释义 |
|fossil_range = {{fossil range|Oxfordian|ref=[1]}} |regnum = Animalia |phylum = Mollusca |classis = Cephalopoda |subclassis = Ammonoidea |ordo = Ammonitida |familia = Perisphinctidae |genus = Balticeras |genus_authority = Dohm, 1925 |subdivision_ranks = Species [1] |subdivision = None }} Balticeras is an involute, discoidal Upper Jurassic (Oxfordian) ammonite[2] (order Ammonitida) found in England, Germany, and Switzerland, belonging to the Perisphinctidae. The shell is strongly embracing, tending to be oxyconic (sharp rimmed). Sides are gently curved, converging on a narrow to sharp ventral rim. Balticeras is considered by some to be a subgenus of Ringsteadia which in contrast is more evolute, with ribbed inner whorls. Both are included in the Pictoniinae, a subfamily established by Spath, 1924, for large ammonites within the Perisphinctidae, tending to develop smooth middle and outer whorls. References
1. ^{{cite web | title= Paleobiology Database - 'Balticeras |authorlink =| coauthors =| year = | url = http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=14605| accessdate = 2014-05-28 }} 2. ^1 {{cite web | last = Sepkoski| first = Jack| title= Sepkoski's Online Genus Database|authorlink =| coauthors =| year = 2002| url = http://strata.geology.wisc.edu/jack/showgenera.php?taxon=231&rank=class| accessdate = 2014-05-28 }}
5 : Jurassic ammonites|Ammonites of Europe|Oxfordian life|Ammonitida genera|Perisphinctidae |
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