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The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 Ma. The Albian is preceded by the Aptian and followed by the Cenomanian.
Euhoplites is an extinct ammonoid cephalopod from the Lower Cretaceous, characterized by strongly ribbed, more or less evolute, compressed to inflated shells with flat or concave ribs, typically with a deep narrow groove running down the middle. In some, ribs seem to zigzag between umbilical tubercles and parallel ventrolateral clavi. In others the ribs are flexuous and curve forward from the umbilical shoulder and lap onto either side of the venter.
Acanthohoplites is an extinct genus of ammonites in the family Parahoplitidae that lived in the Aptian and Early Albian stages of the Early Cretaceous.
Anahoplites is a genus of rather involute, compressed hoplitid ammonites with flat sides, narrow flat or grooved venters, and flexious ribs or striae arising from weak umbilicle tubercles that end in fine dense ventrolateral nodes. The elements of their sutures are short, wide and jaggedy. Specimens of Annahoplites have diameters typically in the range of 4–6 centimetres (1.6–2.4 in) although some with diameters of as much as 19 centimetres (7.5 in) have been reported. The genus lived during the Cretaceous, from the Middle to the late Albian.
Anisoceras is a heteromorph ammonite belonging to the turrilitoid family Anisoceratidae. The shell forms a loose open helical spiral in the early stages, ending in one or two straight shafts in the mature adult. Surface ornament consists of prominent rounded nodes on the lower and upper flanks, connected by strong looped ribs. The nodes may have been the bases of long sharp spines.
Coilopoceratidae is a family of generally large, proper ammonites with strongly involute shells from the Cretaceous, Albian to Turonian. Coilopoceratids have variably compressed shells with flattish to broadly rounded sides and narrowly rounded to sharp keel-like venters. Whorl sections are generally lanceolate. The suture is ammonitic with an overall clumpy appearance.
Anisoceratidae is an extinct family of heteromorph ammonites which belong to the Ancyloceratina superfamily Turrilitoidea. Members of the family range is from the lower Albian to the upper Turonian. The family is possibly derived from a member of the Hamitidae.
Hoplites is a genus of ammonite that lived from the Early Albian to the beginning of the Middle Albian. Its fossils have been found in Europe, Transcaspia and Mexico. Shell has compressed, rectangular till depressed and trapezoidal whorl section. There are strong umbilical bullae from which, prominent ribs are branching and these are interrupted on venter. Ends of ribs on the venter are prominent and can be both alternate or opposite. Some species have zigzagging ribs and these ribs ends usually thickened, or they can be raised into ventrolateral tubercles. These tubercles are mostly oblique clavi.
Coilopoceras is a compressed, involute, lenticular ammonitid from the Cretaceous, with a narrow venter and raggedy ammonitic suture; type of the Coilopoceratidae, a family in the Acanthoceratoidea of the suborder Ammonitina.
Placenticeratidae is an extinct family of mostly Late Cretaceous ammonites included in the superfamily Hoplitoidea, derived from the Engonoceratidae by an increase in suture complexity.
Shloenbachiidae is a family of hoplitoid ammonoid cephalopds mostly from the lower Upper Cretaceous,.
Callihoplites is a genus of rather evolute ammonites from the Lower Cretaceous, Late Albian. Its whorl section squarish or compressed, inner whorls bearing umbilical bullae and ventrolateral clavi, with or without looped ribs between. The body chamber is smooth with a rounded venter.
Dipoloceras is a rather evolute, strongly ribbed and well keeled acanthocerataean ammonite from the Albian stage of the Lower Cretaceous included in the brancoceratid subfamily Mojsisovicziinae. The whorl section is typically inflated or depressed. Ribs are high standing, may be sharp, close to wide spaced. The ventral keel may sit below the level of the ribs.
Brancoceratidae is a family of acanthoceratoid ammonites from the middle of the Cretaceous, recognized by their commonly evolute shells with round, oval, or quadrate whorls, strong ribs, usual ventral keels, and at least, umblical tubercles. The family is thought to be derived from the Desmoceratidae (Desmoceratoidea), perhaps from Silesitoides or some allied genus.
Ancyloceratidae is a family of heteromorphic ammonites that lived during the Early Cretaceous. Their shells begin as a loose spiral with whorls not touching which then turns into a straight shaft that ends in a J-shape hook or bend at end. Coarse ribbing and spines are common.
Hypophylloceras is a Cretaceous ammonite with a finely ribbed, compressed, involute shell; some having periodic stronger ribs or folds. The suture is complex, with large, asymmetric and finely divided lobes; the 1st lateral being much larger than the external (=ventral) and 2nd lateral lobes. Saddle endings commonly not phylloid.
Leymeriellidae is a family of Lower Cretaceous ammonites comprising rather small forms distinguished from Hoplitidae by their flattened and grooved ribs and virtual absence of umbilical tubercles. The family is derived from the Desmoceratidae. Leymeriella schrammeni anterior has evolved from Desmoceras keilhacki keilhacki.
Melchiorites is a desmoceratid ammonite genus included in the subfamily Puzosiinae. Member species are characterized by an essentially evolute shell in which the early whorls are smooth, with sinuous radial or oblique constrictions but in which later whorls have feeble intermediate ribs on the outer part of the sides and venter.
Otohoplites is a genus of ammonite that lived in the Early Albian and whose fossils were found in Svalbard, Denmark, England, France, Austria, Poland, Russia and Kazakhstan. It has evolved from Hemisonneratia and gave rise to genus Hoplites. Shells belonging to this genera are rather inflated to compressed and have zigzaging, or looped ribs that ends in oblique ventrolateral clavi. Usually, ribs are zigzaging through venter. Macroconchs have smooth body chamber and rounded venter.
References
- Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press.
- Ryszard Marcinowski and Jost Wiedmann. The Albian Ammonites of Poland. Palaeontologia Polonica no. 50, 1990
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