Cretolamna
occasionally spelled as Cretalamna

Name: Cretolamna ‭(‬Cretaceous Lamna‭)‬.
Phonetic: Cree-toe-lam-nah.
Named By: Glikman‭ ‬-‭ ‬1958.
Synonyms: Lamna appendiculata,‭ ‬Lamna appendiculatus,‭ ‬Otodus appendiculatus.
Classification: Chordata,‭ ‬Chondrichthyes,‭ ‬Elasmobranchii,‭ ‬Selachimorpha,‭ ‬Lamniformes.
Species: C.‭ ‬appendiculata,‭ ‬C.‭ ‬appendiculata appendiculata,‭ ‬C.‭ ‬appendiculata pachyrhiza,‭ ‬C.‭ ‬aschersoni,‭ ‬C.‭ ‬biauriculata,‭ ‬C.‭ ‬gunsoni,‭ ‬C.‭ ‬lata,‭ ‬C.‭ ‬maroccana,‭ ‬C.‭ ‬pachyrhiza.
Diet: Carnivore/Piscivore.
Size: ‭ ‬Average length seems to have been anywhere between‭ ‬2‭ ‬to‭ ‬3‭ ‬meters,‭ ‬though rare examples indicate an upper size approaching‭ ‬3.6‭ ‬meters long.
Known locations: Fossils are literally known in age appropriate marine deposits worldwide.
Time period: Roughly Barremian of the Cretaceous to the Mid Miocene.
Fossil representation: Mostly teeth and vertebrae.

       Although the Cretolamna shark genus is extinct today,‭ ‬there is no doubt that it was one of the most successful of all shark genera.‭ ‬Fossils of Cretolamna‭ (‬mostly of teeth and vertebrae‭) ‬are known from all over the world and range from the early Cretaceous to the mid Miocene in age,‭ ‬making Cretolamna one of the most widely distributed shark genera in not just geographical range but throughout time as well.‭ ‬Only a few other shark genera such as Hybodus can claim to rival this success.‭ ‬Because the first fossils of Cretolamna were found in Cretaceous aged deposits,‭ ‬the genus was given a name which means‭ ‘‬Cretaceous Lamna‭’‬,‭ ‬with the Lamna part referencing the similarity to the Lamna shark genus,‭ ‬which is the type genus of the Lamniformes group of sharks‭ (‬The group that includes many modern kinds such as the great‭ ‬white,‭ ‬thresher shark,‭ ‬porbeagle,‭ ‬mako,‭ ‬etc‭)‬.
       Cretolamna would have looked much like modern day lamniform sharks,‭ ‬and likely would have been a pelagic‭ (‬open water‭) ‬predator of other fish.‭ ‬However,‭ ‬Cretolamna living before the KT extinction during the Cretaceous and would have had the option to hunt marine reptiles such as plesiosaurs and smaller mosasaurs,‭ ‬while those living after the KT extinction may have attacked primitive cetaceans,‭ ‬many of which were much smaller than those we know today.‭ ‬The teeth of Cretolamna are broad with cusps at the base of the main crown,‭ ‬indicating that Cretolamna was best suited to attacking larger prey.
       It is hard to be certain about exactly which different evolutionary lines that different sharks evolved from.‭ ‬However in the past the Cretolamna genus has been speculated to be the origin of other large predatory sharks,‭ ‬including the genera Otodus,‭ ‬and Paleocarcharodon.‭ ‬Paleocarcharodon is regarded as a possible ancestor to Carcharodon carcharias,‭ ‬today better known as the great white shark,‭ ‬and largest predatory shark alive today‭ (‬basking and whale sharks are larger but these are filter feeders‭)‬.‭ ‬Otodus however may have been the progenitor of the Carcharocles genus which includes such behemoths as C.‭ ‬angustidens,‭ ‬C.‭ ‬auriculatus,‭ ‬C.‭ ‬chubutensis,‭ ‬and largest of all,‭ ‬C.‭ ‬megalodon.


Cardabiodon, Cretolamna, Cretoxyrhina, Hybodus, Ptychodus, Scapanorhynchus, Squalicorax.

Further reading

-‭ ‬Skeletal and dental anatomy of lamniform shark,‭ ‬Cretalamna appendiculata,‭ ‬from Upper Cretaceous Niobrara Chalk of Kansas‭ ‬-‭ ‬Journal of Vertebrate Paleontology vol‭ ‬27,‭ ‬Issue‭ ‬3‭ ‬-‭ ‬Kenshu Shimada‭ ‬-‭ ‬2007.
-‭ ‬Late Cretaceous‭ (‬Cenomanian-Campanian‭) ‬mid-palaeolatitude sharks of Cretalamna appendiculata type‭ ‬-‭ ‬Acta Palaeontologica Polonica.‭ ‬-‭ ‬Mikael Siverson,‭ ‬Johan Lindgren,‭ ‬Michael G.‭ ‬Newbrey,‭ ‬Peter Cederström‭ & ‬Todd D.‭ ‬Cook‭ ‬-‭ ‬2013.





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