NJfossils.com

Fossils from Monmouth County, New Jersey

Mackerel (Cretalamna “appendiculata” aka Cretolamna “appendiculata“)

Age – Late Cretaceous; Commonality – Common (slightly less common than Archaeolamna); Size – average: a little under ¾ inch, max: 1 inch (in our area)

Cretalamna are probably my favorite type of tooth to find because of their attractive appearance.

These teeth are similar to the teeth of Archaeolamna. The main differences are in the cusplets and the lingual protuberance. The cusplets are scalloped and lower, especially in anterior teeth. The lingual protuberance is reduced and the whole tooth is a little more flattened compared to Archaeolamna. There are several Cretalamna species represented in New Jersey. Referring all of them to the “species” appendiculata is likely wrong (even though that is the trend among NJ collectors), especially when appendiculata is strictly a Turonian species. Quotations around “appendiculata” are necessary as it is a paleobucket (a species name that is used to group many indeterminate/undescribed species under). cf. Cretalamna biauriculata maroccana is an example of another Cretalamna type of tooth that can be found (although much more rarely). The teeth pictured below are the “common” type.

Cretalamna is also special in that it possessed a cutting dentition, which is different from the tearing/grasping dentitions of most Cretaceous sharks. Cutting dentitions are the most efficient type of dentition (information from Siteseer on TheFossilForum). It is most likely what makes Cretalamna one of the most successful genuses, living from the Albian to the Ypresian.

 They are thought to be a distant ancestor to Otodus (Carcharocles) megalodon. 

Anterior Teeth

Lingual View

Labial View

Profile View of Mesial Side

Profile View of Distal Side

Occlusal View

This is a large lower anterior (likely an a2) tooth. It has some very reduced cusplets in comparison to its cusp size. It also has an interesting indentation on the lingual side of the root (above the cusplet at the right when looking at the lingual side of the root with the root at the top). I suspect this relatively narrow and deep indentation could be from the shark biting its own tooth after it was shed.

Lingual View

Labial View

Profile View of Mesial Side

Profile View of Distal Side

Basal View

Occlusal View

This tooth is another lower anterior (likely an a3). It has relatively larger root lobes and lingual protuberance and a shorter and stouter crown than the tooth above.

Lingual View

Labial View

Mackerel Shark Cretaceous (Cretalamna appendiculata) Anterior tooth, New Jersey

Profile View of Mesial Side

Profile View of Distal Side

This tooth is a juvenile lower anterior C. appendiculata. It has quite a different morphology when compared to an adult anterior tooth. Its cusplets are larger compared to its overall size and look similar to the sharp, pointed cusplets on an A. kopingensis.

Lateral Teeth

Lingual View

Labial View

Mackerel Shark Cretaceous (Cretalamna appendiculata) Lateral tooth, New Jersey

Profile View of Mesial Side

Profile View of Distal Side

This is a C. appendiculata upper lateral tooth. Lateral teeth have a more distally slanted crown and relatively wider root. Lateral teeth are generally more common than anteriors; this is because C. appendiculata possessed many more lateral tooth files than anterior tooth files (like most sharks).

Lingual View

Labial View

Profile View of Mesial Side

Profile View of Distal Side

This lower lateral tooth has a different form than the lateral tooth above. This is because it is from a different lateral tooth file from the shark’s dentition.

Lingual View

Labial View

Profile View of Mesial Side

Profile View of Distal Side

This upper lateral has some labial wrinkles on its crown. C. appendiculata teeth usually have a smooth crown surface. This tooth also has a nice orange color which is uncommon.

Posterior Teeth

Lingual View

Labial View

Profile View of Mesial Side

Profile View of Mesial Side

Profile View of Distal Side

Occlusal View

Posterior C. appendiculata teeth are reduced in size in comparison to anteriors and laterals (although not as reduced in size as posterior A. kopingensis teeth). They are even more slanted distally and have an even greater relative width compared to laterals. This upper posterior has an interesting root variation. The sides of the root along with the cusplets are bent toward the lingual face of the tooth. This feature can be observed in occlusal view.

Lingual View

Labial View

Mackerel Shark Cretaceous (Cretalamna appendiculata) Posterior tooth, New Jersey

Profile View of Mesial Side

Profile View of Distal Side

This is a small posterior tooth (likely an upper). It likely came from a juvenile or a sub-adult. It seems like C. appendiculata possessed no or very few (1 or 2) lower posterior files. Most posterior teeth are uppers.

Content copyright 2018: njfossils.com. All rights reserved.