The family Dactylioceratidae comprises Early Jurassic ammonite genera with ribbed and commonly tuberculate shells that resembled later Middle Jurassic stephanoceratids and Upper Jurassic perisphinctids. Shells may be either evolute or involute.
Ammonites with evolute, serpenticone to cadicone shells with ribs, sometimes with tubercules. Members of this family had no keels. while homeomorphic with stephanoceratids and perisphinctids, they had unique shell structure with double shells and flat-topped ribs on the inner shell. Based on suture differences, they are divided into 2 subfamilies. Reynesocoeloceratinae possess two major secondary lobes in dorsal side of external saddle. This saddle is not divided this way in Dactylioceratinae, while lateral lobe is deeply trifid.[1]
Evolutionedit
It has been suggested, that this family is polyphyletic, but this is now considered to be false. Reynesocoeloceratinae evolved in lower Pliensbachian from Metaderoceras and died out in upper Pliensbachian. Reynesoceras oldest member of Dactylioceratinae evolved in upper Pliensbachian from Cetonoceras, or Prodactylioceras. This subfamily died out in middle Toarcian, during Variabilis zone.[1]
^Yu.S. Repin (2016). "Lower Jurassic ammonite geologic time scale of Northeast Asia". Neftegasovaâ Geologiâ. Teoriâ i Practika. 11 (4): 1–45. doi:10.17353/2070-5379/47_2016.
Bibliography
W. Arkell et al., 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology, Part L. Geological Society of America and University of Kansas, Press.
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dactylioceratidae, family, comprises, early, jurassic, ammonite, genera, with, ribbed, commonly, tuberculate, shells, that, resembled, later, middle, jurassic, stephanoceratids, upper, jurassic, perisphinctids, shells, either, evolute, involute, temporal, rang. The family Dactylioceratidae comprises Early Jurassic ammonite genera with ribbed and commonly tuberculate shells that resembled later Middle Jurassic stephanoceratids and Upper Jurassic perisphinctids Shells may be either evolute or involute DactylioceratidaeTemporal range early Jurassic PreꞒ Ꞓ O S D C P T J K Pg NAmmonites of genus Dactylioceras from Schleifhausen Germany Scientific classificationDomain EukaryotaKingdom AnimaliaPhylum MolluscaClass CephalopodaSubclass AmmonoideaOrder AmmonitidaSuperfamily EoderoceratoideaFamily DactylioceratidaeHyatt 1867 Contents 1 Description 2 Evolution 3 Taxonomy 4 ReferencesDescription edit nbsp Prodactylioceras cf davoeiAmmonites with evolute serpenticone to cadicone shells with ribs sometimes with tubercules Members of this family had no keels while homeomorphic with stephanoceratids and perisphinctids they had unique shell structure with double shells and flat topped ribs on the inner shell Based on suture differences they are divided into 2 subfamilies Reynesocoeloceratinae possess two major secondary lobes in dorsal side of external saddle This saddle is not divided this way in Dactylioceratinae while lateral lobe is deeply trifid 1 Evolution editIt has been suggested that this family is polyphyletic but this is now considered to be false Reynesocoeloceratinae evolved in lower Pliensbachian from Metaderoceras and died out in upper Pliensbachian Reynesoceras oldest member of Dactylioceratinae evolved in upper Pliensbachian from Cetonoceras or Prodactylioceras This subfamily died out in middle Toarcian during Variabilis zone 1 nbsp Approximate timeline of Dactylioceratidae genera Taxonomy edit 1 2 3 Dactylioceratidae Hyatt 1867 Reynesocoeloceratinae Dommergues 1986 Reynesocoeloceras Geczy 1976 Bettoniceras Wiedenmayer 1977 Prodactylioceras Spath 1923 Cetonoceras Wiedenmayer 1977 Dactylioceratinae Hyatt 1867 Reynesoceras Spath 1936 Dactylioceras Hyatt 1867 D Dactylioceras Hyatt 1867 D Orthodactylites Buckman 1926 D Iranodactylites Repin 2000 D Eodactylites Schmidt Effing 1972 Nodicoeloceras Buckman 1926 Peronoceras Hyatt 1867 Zugodactylites Buckman 1926 Porpoceras Buckman 1911 Septimaniceras Faure 2002 Catacoeloceras Buckman 1923 Collina Bonarelli 1893 Tokurites Repin 2016References editNotes a b c M K Howarth 2013 Treatise on Invertebrate Paleontology Part L Revised Volume 3B Chapter 4 Psiloceratoidea Eoderoceratoidea Hildoceratoidea Paleobiology Database Dactylioceratidae Retrieved 2017 10 19 Yu S Repin 2016 Lower Jurassic ammonite geologic time scale of Northeast Asia Neftegasovaa Geologia Teoria i Practika 11 4 1 45 doi 10 17353 2070 5379 47 2016 BibliographyW Arkell et al 1957 Mesozoic Ammonoidea Treatise on Invertebrate Paleontology Part L Geological Society of America and University of Kansas Press nbsp This Ammonitina related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Dactylioceratidae amp oldid 1165998278, wikipedia, wiki, book, books, library,
