cjlaw “at” ucsc.edu
Personal Site: chrisjlaw.com
My research examines the processes that contribute to the phenotypic and ecological variation found across both macroevolutionary and microevolutionary scales.
*Please contact me through ResearchGate if you are unable to access any of the pdfs. I am happy to send them to you*
high school/undergraduate student mentee
17) Law CJ. Accepted. Evolutionary shifts in extant mustelid (Mustelidae: Carnivora) cranial shape, body size, and body shape coincides with the Mid-Miocene Climate Transition. Biology Letters.
16) Law CJ, Slater GJ, & Mehta RS. 2018. Shared extremes by ectotherms and endotherms: Body elongation in mustelids is associated with small size and reduced limbs. Evolution. 73:735–749.
Weasels are elongate! Specifically, mustelids exhibit an evolutionary transition toward more elongate bodies driven by the elongation of the head and various regions of the axial skeleton
The elongation of the body is associated with the evolutionary reduction of body size and a reduction in forelimb length but not hindlimb length
The relationship between body elongation and forelimb length has not previously been quantitatively established for mammals but is consistent with trends exhibited by ectothermic vertebrates and suggests a common pattern of trait covariance associated with body shape evolution
15) Law CJ, Duran E, Hung N, Richards E, Santillan I, & Mehta RS. 2018. Effects of diet on cranial morphology and biting ability in musteloid mammals. Journal of Evolutionary Biology. 31:1918-1931.
Cranial size but not cranial shape predicts estimated bite forces in musteloids
Many-to-one mapping of form to function may explain this pattern as the cranium is complex, and a variety of morphological shape differences contribute to similar relative biting performance outcomes
Musteloids with different diets exhibit different cranial shapes; however, they have similar estimated bite forces suggesting that other feeding performance metrics and potentially nonfeeding traits are also important contributors to cranial evolution
14) Higgins BA, Law CJ, & Mehta RS. 2018. Eat whole and less often: ontogenetic shift reveals size specialization on kelp bass by the California moray eel, Gymnothorax mordax. Oecologia. 188:875–887.
California morays are dietary specialists, feeding primarily on kelp bass despite not being the most commonly occurring fish species in the environment
California morays exhibit an ontogenetic shift for kelp bass where maximum prey size increases with moray size but smaller prey are dropped from the diet
Moray bite forces increased disproportionately with increasing head size, suggesting that larger morays can consume prey that exceed their head lengths; however, there was no significant relationship between prey size and moray bite force, indicating that prey size selection is not limited by moray bite force
13) Law CJ & Mehta RS. 2018. Carnivory maintains cranial dimorphism between males and females: Evidence for niche divergence in extant Musteloidea. Evolution. 72:1950–1961.
Niche divergence rather than sexual selection maintains the evolution of sexual dimorphism in cranial size and bite force across Musteloidea
Hypercarnivorous musteloids exhibit the greatest degree of cranial size and bite force dimorphism; in contrast, neither dietary regime nor social system influenced the evolution of sexual dimorphism in cranial shape
These results demonstrate the importance of diet in reducing intraspecific competition for resources as an important mechanism that maintains the evolution of sexual dimorphism in extant musteloids.
12) Law CJ, Slater G, & Mehta RS. 2018. Lineage diversity and size disparity in Musteloidea: testing patterns of adaptive radiation using molecular and fossil-based methods. Systematic Biology. 67:127–144.
Musteloids do not exhibit an adaptive radiation as previously hypothesized; however, a subclade of “elongate” mustelids exhibit increased lineage carrying capacity and increased rates of body length evolution but not body mass evolution
Lack of correspondence in rates of body mass and length evolution suggest that phenotypic evolutionary rates under a single morphological metric may not capture the evolution of diversity in clades that exhibit elongate body shapes
These results suggest that body elongation led to the radiation of some musteloids
11) Jones K† & Law CJ†. 2018. Differentiation of craniomandibular morphology in two sympatric Peromyscus mice (Cricetidae: Rodentia). Mammal Research. 63:277–283. †Joint first authors
Granivorous Pinyon mice (Peromyscus truei) exhibit skulls that facilitate relatively larger jaw adductor muscles compared to insectivorous California mice (Peromyscus californicus)
Pinyon mice also exhibit higher mechanical advantage of the masseter jaw muscle
These traits are consistent with the dietary differences exhibited by the two sympatric species
Literature review of the Siberian weasel
9) Kienle SS, Law CJ, Costa DP, Berta A, & Mehta RS. 2017. Revisiting the behavioural framework of feeding in predatory aquatic mammals. Proceedings of the Royal Society B. 284:20171035.
An aquatic tetrapod feeding cycle with 5 stages—ingestion, intraoral transport, processing, water removal and swallowing—allows aquatic mammals to be examined in the same framework as other tetrapods and provides flexibility to accommodate behaviorally diverse lineages
Evolution of aquatic tetrapod feeding is not a progression of linear events and should be modeled as a tree-like process
8) Law CJ, Baliga VB, Tinker MT, & Mehta RS. 2017. Asynchrony in craniomandibular development and growth in Enhydra lutris nereis (Carnivora: Mustelidae): Are southern sea otters born to bite? Biological Journal of Linnean Society. 121:420-438
The majority of sea otter skull growth and development occurs during the pup stage; however, the skull does not fully mature until adulthood and therefore may constrain feeding on hard-shelled prey
Sexual dimorphism in adult skulls arose through differences in developmental and growth rates and duration
Male crania mature faster to presumably reach adult biting ability sooner, gaining a competitive advantage in obtaining food and in male–male agonistic interactions
Literature review of the Eurasian otter
6) Law CJ, Young C, and Mehta RS. 2016. Ontogenetic scaling of theoretical bite forces in southern sea otters (Enhydra lutris nereis). Physiological and Biochemical Zoology 89:347-363.
Sea otters exhibit positive allometric increases in theoretical bite force, which is primarily driven by allometric increases in temporalis muscle mass
Adult males exhibited greater bite forces as a result of their larger sizes
However, scaling patterns of theoretical bite force and morphological traits do not differ between the sexes
5) Law CJ, Venkatram V, & Mehta RS. 2016. Sexual dimorphism of craniomandibular morphology in southern sea otters (Enhydra lutris nereis). Journal of Mammalogy. 97:1764-1773.
Male sea otters exhibit larger skulls compared to females
Sea otters also exhibit significant shape differences driven by 3 craniomandibular traits that increase the surface area of jaw muscle attachment sites
These morphological differences indicate males and females may also exhibit differences in biting abilities
4) Baliga VB & Law CJ. 2016. Cleaners amongst wrasses: phylogenetics and evolutionary patterns of cleaning behavior within Labridae. Molecular Phylogenetics and Evolution 94A:424–435.
3) Law CJ, Dorgan KM, & Rouse GW. 2014. Relating divergence in polychaete musculature to different burrowing behaviors: A study using Opheliidae (Annelida). Journal of Morphology. 571:548–571.
2) Dorgan KM, Law CJ, & Rouse GW. 2013. Meandering worms: Mechanics of undulatory burrowing in muds. Proceedings of the Royal Society B. 280:20122948.
1) Law CJ, Dorgan KM, & Rouse GW. 2013. Validation of three sympatric Thoracophelia species (Annelida: Opheliidae) from Dillon Beach, California using mitochondrial and nuclear DNA sequence data. Zootaxa. 3608:67–74.