Tooth Microstructure and Replacement in the Gulper Shark, Centrophorus granulosus (Squaliformes: Centrophoridae)
This study describes the teeth, dentition, and tooth replacement pattern of the Gulper Shark, Centrophorus granulosus, using histology and micro-CT scanning. Tooth microstructure and the orthodont histotype of C. granulosus are described and illustrated, and tooth morphology is discussed in the context of squaliform phylogenetic studies. Dental characters previously used to study squaliform interrelationships need revision. The dentitions of adult and near-term pups are documented to illustrate ontogenetic changes in tooth morphology as well as the pattern of tooth replacement. Based on the positions of replacement teeth in each tooth file, the replacement pattern of the palatoquadrate dentition is best described as phased sinusoidal replacement. This study also documents the monognathic and dignathic heterodonty of pups and adults, confirming previously published descriptions of heterodonty that have proven to be of taxonomic significance. A revised dental formula is provided that better reflects the tooth morphologies of the species.
Arrangement of functional teeth on the left side of a specimen of Centrophorus granulosus (CUMV 98251). Tooth loci are numbered from the symphyses distally. Scale bar = 1 cm.
Photomicrographs of individual teeth of Centrophorus granulosus (CUMV 98251). (A) Labial view of LP3F1 tooth. (B) Lingual view of the same tooth shown in A. (C) Labial view of LM8F1 tooth. (D) Lingual view of the same tooth shown in C. Scale bars = 0.5 cm.
Three-dimensional reconstructions of jaws of a near-term pup of Centrophorus granulosus generated from CT data (CUMV 98253). (A) Labial view showing incomplete mineralization of the palatoquadrate and Meckel's cartilage. Rows of replacement teeth on the lingual side of the jaw are visible through the incompletely mineralized palatoquadrate and Meckel's cartilage. (B) Lingual view showing rows of functional and replacement teeth. Scale bars = 0.5 cm.
Lingual view of LP1 through LP8 replacement series in Centrophorus granulosus (CUMV 98330). (A) Photograph of replacement teeth descending into functional positions. (B) Line drawing of the visible functional teeth and first replacement teeth in the boxed area of Part A of this figure. Replacement teeth show a phased sinusoidal pattern of descent into functional positions. Scale bars = 0.5 cm.
Light micrographs of a vertical section of RM5F1 tooth of a mature female Centrophorus granulosus (CUMV 98251). (A) Entire tooth section identifying tissue types and their arrangement. Scale bar = 1 mm. (B) Same section as in A viewed with polarized light. Scale bar = 1 mm. (C) Higher magnification of the boxed area shown in A. Scale bar = 100 μm. (D) Higher magnification of the boxed area from shown in A viewed with polarized light. Scale bar = 100 μm.
Three-dimensional virtual reconstruction of RP4F1 and RP5F1 teeth from a mature female Centrophorus granulosus (CUMV 98251) generated from CT data. (A) Labial view. (B) Lingual view. (C) Labial view with the labial surfaces digitally removed to reveal internal anatomy of the teeth. Scale bars = 2.5 mm.
Three-dimensional virtual reconstruction of LM6F1 tooth from a mature female Centrophorus granulosus (CUMV 98251) generated from CT data. (A) Labial view. (B) Lingual view. (C) Labial view with the labial surface digitally removed to reveal internal anatomy of the tooth. Scale bars = 2.5 mm.
Contributor Notes
Associate Editor: D. Buth.