Brain Size and Brain Organization of the Whale Shark, <i>Rhincodon typus</i>, Using Magnetic Resonance Imaging
2009/01/01 by Kara E. Yopak, Lawrence R. Frank · 59 citations
Environmental Science · #Anatomy #Biology #Carcharias #Central nervous system #Cerebellum #Cerebrum #Diencephalon #Ecology #Endocrinology #Fish biology, ecology, and behavior #Hypothalamus #Ichthyology and Marine Biology #Juvenile #Marine animal studies overview
paper · doi:10.1159/000235962
published in Brain Behavior and Evolution 74(2), 121-142 (Karger Publishers)
openalex publication_date 2009/01/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/04
Abstract
Very little is known about the brain organization of the suction filter feeder, Rhincodon typus, and how it compares to other orectolobiforms in light of its specialization as a plankton-feeder. Brain size and overall brain organization was assessed in two specimens of R. typus in relation to both phylogeny and ecology, using magnetic resonance imaging (MRI). In comparison to over 60 other chondrichthyan species, R. typus demonstrated a relatively small brain for its body size (expressed in terms of encephalization quotients and residuals), similar to the lamniforms Carcharodon carcharias, Cetorhinus maximus, and Carcharias taurus. R. typus possessed a relatively small telencephalon with some development of the dorsal pallium, which was suggestive of moderate social behavior, in addition to a relatively large diencephalon and a relatively reduced mesencephalon. The most notable characteristic of the brain of Rhincodon was a large and highly foliated cerebellum, one of the largest cerebellums within the chondrichthyan clade. Early development of the brain was qualitatively assessed using an in situ MRI scan of the brain and chondrocranium of a neonate specimen of R. typus. There was evidence that folding of the cerebellar corpus appeared in early development, although the depth and number of folds might vary ontogenetically in this species. Hierarchical cluster analysis and multidimensional scaling ordinations showed evidence of convergent evolution with the basking shark, Cetorhinus maximus, another large-bodied filter feeding elasmobranch, supporting the claim that organization of the brain is more similar in species with analogous but independently evolved lifestyles than those that share taxonomic classification.
Citations
Cited by
- Foraging and Ingestive Behaviors of Whale Sharks, Rhincodon typus, in Response to Chemical Stimulus Cues
- The neuroecology of the water-to-land transition and the evolution of the vertebrate brain
- Draft sequencing and assembly of the genome of the world’s largest fish, the whale shark: Rhincodon typus Smith 1828
- A review of the biology, fisheries and conservation of the whale shark Rhincodon typus
- Armored eyes of the whale shark
- The Digital Fish Library: using MRI to digitize, database, and document the morphological diversity of fish. [europepmc]
- Ontogenetic shifts in brain scaling reflect behavioral changes in the life cycle of the pouched lamprey Geotria australis. [europepmc]
- Learning from a provisioning site: code of conduct compliance and behaviour of whale sharks in Oslob, Cebu, Philippines. [europepmc]
- Quantitative Classification of Cerebellar Foliation in Cartilaginous Fishes (Class: Chondrichthyes) Using Three-Dimensional Shape Analysis and Its Implications for Evolutionary Biology. [europepmc]
- Draft sequencing and assembly of the genome of the world's largest fish, the whale shark: Rhincodon typus Smith 1828. [europepmc]
- Bridging disciplines to advance elasmobranch conservation: applications of physiological ecology. [europepmc]
- Comparative Brain Morphology of the Greenland and Pacific Sleeper Sharks and its Functional Implications. [europepmc]
- diceCT: A Valuable Technique to Study the Nervous System of Fish. [europepmc]
- Armored eyes of the whale shark. [europepmc]
- Mandibular musculature constrains brain-endocast disparity between sarcopterygians. [europepmc]
- Unveiling the third dimension in morphometry with automated quantitative volumetric computations. [europepmc]
- The neuroecology of the water-to-land transition and the evolution of the vertebrate brain. [europepmc]
- Smart sharks: a review of chondrichthyan cognition. [europepmc]
- Quantitative assessment of inner ear variation in elasmobranchs. [europepmc]
- A detailed 3D MRI brain atlas of the African lungfish Protopterus annectens. [europepmc]
- Bioimaging of sense organs and the central nervous system in extant fishes and reptiles in situ: A review. [europepmc]
- Brain Morphology and Quantitative Assessment of Sensory Brain Areas in Southern Bluefin Tuna, Thunnus maccoyii (Scombridae, Teleostei). [europepmc]
- Flow-driven patterns of whale shark movement in the Red Sea. [europepmc]
Related