Phillip Sternes

Shark Measurements

The versatility of the shark body form is suggested to be one of the key factors underlying their evolutionary success and persistence. Nevertheless, sharks exhibit a huge diversity of body forms and morphological adaptations. More subtly, it is increasingly evident that in many species, morphology varies through ontogeny. Multiple competing hypoth...

Supplementary data used in this study, including a review of over 60 cases of body size estimation controversies in fossil animals.

Body size is of fundamental importance to our understanding of extinct organisms. Physiology, ecology and life history are all strongly influenced by body size and shape, which ultimately determine how a species interacts with its environment. Reconstruction of body size and form in extinct animals provides insight into the dynamics underlying comm...

Synopsis Systematic trends in body size variation exist in a multitude of vertebrate radiations, however their underlying ecological and evolutionary causes remain poorly understood. Rensch's rule describes one such trend—in which the scaling of sexual size dimorphism (SSD) depends on which sex is larger. Where SSD is male-biased, SSD should scale...

While sexual size dimorphism (SSD) is abundant in nature, there is huge variation in both the intensity and direction of SSD. SSD results from a combination of sexual selection for large male size, fecundity selection for large female size and ecological selection for either. In most vertebrates, it is variation in the intensity of male–male compet...

Elasmobranchs (sharks and rays) exhibit a wide range of body forms adapted to various ecological niches. Body form differs not only between species, but between life stages of individual species as a result of ontogenetic allometry. In sharks, it has been proposed that these ontogenetic shifts in body form result from shifts in trophic and/or spati...

The white shark (Carcharodon carcharias) is the largest macropredatory fish in the world. Yet, there remains a paucity of data on the early life history and reproduction of this iconic shark. Here, we present aerial observations of an individual white shark that appears to be sloughing a white film from its body. We propose two possibilities for th...

The megatooth shark, †Otodus megalodon, which likely reached at least 15 m in total length, is an iconic extinct shark represented primarily by its gigantic teeth in the Neogene fossil record. As one of the largest marine carnivores to ever exist, under�standing the biology, evolution, and extinction of †O. megalodon is important because it had a s...

Disproportional changes (i.e. allometry) in shark morphology have been attributed to shifts in function associated with niche shifts in life history, such as in habitat and diet. Photographs of blue sharks ( Prionace glauca , 26-145 kg) were used to analyze changes in parameters of body and fin morphology with increasing mass that are fundamental t...

Major shifts in habitat often occur during life history and can have significant impacts on the morphology and function of an animal; however, little is known about how such ecological changes influence the locomotor system of large aquatic vertebrates. Scalloped hammerheads (Sphyrna lewini) are large sharks found in warm temperate and tropical wat...

Major shifts in habitat often occur during life history and can have significant impacts on the morphology and function of an animal; however, little is known about how such ecological changes influence the locomotor system of large aquatic vertebrates. Scalloped hammerheads (Sphyrna lewini) are large sharks found in warm temperate and tropical wat...

The megatooth shark, Otodus megalodon, is an iconic Neogene lamniform shark known only from its teeth and vertebrae. Its thermophysiology is previously inferred to have been regionally endothermic, like the extant lamnids that are active predatory lamniforms. By considering the entire Lamnidae as the ecological and physiological analogue to O. mega...

Sharks are among the oldest vertebrate lineages in which their success has been attributed to their diversity in body shape and locomotor design. In this study, we investigated the diversity of body forms in extant sharks using landmark-based geometric morphometric analyses on nearly all the known (ca. 470) extant sharks. We ran three different ana...

Squaliformes (dogfish sharks) is a large elasmobranch order with six families (Centrophoridae, Dalatiidae, Etmopteridae, Oxynotidae, Somniosidae, and Squalidae) and over 100 species. A previous study suggested all squaliforms share one basic body plan unlike most other shark orders that have body shape diversity. Here, we used landmark-based geomet...

Lamniformes is a small order of sharks consisting of only 15 extant species but a highly diverse group, including a wide interspecific variation range in their caudal fin shape. A previous study has suggested that caudal fins of lamniforms can be grouped into two types. Type 1 fins have a high aspect ratio and high heterocercal angles, characterize...

We describe seven associated skeletal remains of Ischyrhiza mira, a Late Cretaceous sclerorhynchid sawfish, from the Campanian‒lower Maastrichtian of Tennessee and Alabama, U.S.A., to decipher its paleobiology. Ischyrhiza mira had about 16 or 17 functional spines and about the same number of replacement spines on each side of the rostrum in which t...

Ischyrhiza mira is a Late Cretaceous sclerorhynchid sawfish (Chondrichthyes: Elasmobranchii) that is primarily known by its rostral spines, but its paleobiology remains largely uncertain. Here, we describe seven associated skeletal remains of I. mira from the Campanian-lower Maastrichtian of Tennessee and Alabama, USA. Our study suggests that I. mi...