Otodus angustidens

Otodus angustidens is a species of prehistoric megatoothed sharks in the genus "Otodus", which lived during the Oligocene and Miocene epochs about 33 to 22 million years ago. This shark is related to another extinct megatoothed shark, "Otodus megalodon".
Taxonomy.
The Swiss naturalist Louis Agassiz, first identified this shark as a species of genus "Carcharodon" in 1835.
In 1964, shark expert, L. S. Glikman recognized the transition of "Otodus obliquus" to "C. auriculatus" and moved "C. angustidens" to genus "Otodus". (See "external links" below)
However, in 1987, shark expert H. Cappetta recognized the "C. auriculatus" - "C. megalodon" lineage and placed all related megatooth sharks along with this species in the genus "Carcharocles". The complete "Otodus obliquus" to "C. megalodon" transition then became clear and has since gained the acceptance of many other experts with the passage of time. Within the "Carcharocles" lineage, "C. angustidens" is the species succeeding "C. sokolovi" and is followed by "C. chubutensis".
In 2001, a discovery of the best preserved "Carcharocles angustidens" specimen to date by two scientists, Michael D. Gottfried and Ewan Fordyce, has been presented by the team as evidence for close morphological ties with the extant great white shark, and the team argued that "Carcharocles angustidens", along with all other related megatooth sharks, including "Carcharocles megalodon", should be assigned to "Carcharodon" as was done before by Louis Agassiz., although this is not internationally accepted by the scientific community.
Size estimation.
Like other known megatooth sharks, the fossils of "O. angustidens" indicate that it was considerably larger than the extant great white shark, "Carcharodon carcharias". The well preserved specimen from New Zealand is estimated at in length. This specimen had teeth measuring up to in diagonal length, and vertebral centra around in diameter. However, reports of larger "O. angustidens" fossils have been made.
Dentition.
The dental formula for "O. angustidens" is 
Diet.
"O. angustidens" was an apex predator and likely preyed upon penguins, fish, dolphins, and baleen whales.
Fossil record.
As is the case with most extinct sharks, this species is also known from fossil teeth and some fossilized vertebral centra. Shark skeletons are composed of cartilage and not bone, and cartilage rarely gets fossilized. Hence, fossils of "O. angustidens" are generally poorly preserved. To date, the best preserved specimen of this species have been excavated from New Zealand, which comprises 165 associated teeth and about 35 associated vertebral centra. This specimen is around 26 million years old. "O. angustidens" teeth are noted for their triangular crowns and small side cusps that are fully serrated. The serrations are very sharp and very well pronounced. "O. angustidens" was a widely distributed species with fossils found in: A fossil bed in South Carolina suggests that "O. angustidens" utilized the area as a birthing ground and nursery for their pups, as 89%of the teeth found in the area belonged to juveniles, 3% belonged to infants, and 8% belonged to adults. 