Shovelnose guitarfish
Encyclopedia
The shovelnose guitarfish, Rhinobatos productus, is a ray
that becomes sexually mature at an estimated seven to eight years. Males are between 90–100 cm, while females are around 99 cm at this time. The ray can live up to 11 years, and full grown sizes are around 120 cm for males, and females reach sizes of 137 cm. Their habitat ranges from central California
down to the Sea of Cortez. While remaining the same species, there is a morphological and genetic variation in the mitochondrial DNA in those found in the Sea of Cortez, evidencing the isolation from the rest. The shovelnose is considered to be a primitively developed ray, with many features of both sharks and rays. Because of this, the conservation of this species must be carefully managed to preserve the biological diversity.
The Rhinobatos productus has magnetic particles in the vestibular receptors
, and it is presumed that the magnetic particles are exogenous in origin. The magnetic particles have a spatial arrangement that may aid in the sensitivity of the receptors to movements, but additional research is required.
The visual system of the shovelnose is more extensive and developed than other Elasmobranchii
, with multiple large projections connecting to the brain. Almost the entire dorsal and ventral hypothalamus
is connected to the visual system, but still maintains a similar lack of differentiation as with sharks.
This species has had one documented case of an attack on a diver when a male guitarfish was interrupted during mating. Because of the tooth structure of the guitarfish, this attack could have resulted in a "gumming" at worst.
Shovelnose ray was first considered to be a shark because of its dorsal fin's shape.
Batoidea
Batoidea is a superorder of cartilaginous fish commonly known as rays and skates, containing more than 500 described species in thirteen families...
that becomes sexually mature at an estimated seven to eight years. Males are between 90–100 cm, while females are around 99 cm at this time. The ray can live up to 11 years, and full grown sizes are around 120 cm for males, and females reach sizes of 137 cm. Their habitat ranges from central California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
down to the Sea of Cortez. While remaining the same species, there is a morphological and genetic variation in the mitochondrial DNA in those found in the Sea of Cortez, evidencing the isolation from the rest. The shovelnose is considered to be a primitively developed ray, with many features of both sharks and rays. Because of this, the conservation of this species must be carefully managed to preserve the biological diversity.
The Rhinobatos productus has magnetic particles in the vestibular receptors
Vestibular system
The vestibular system, which contributes to balance in most mammals and to the sense of spatial orientation, is the sensory system that provides the leading contribution about movement and sense of balance. Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of...
, and it is presumed that the magnetic particles are exogenous in origin. The magnetic particles have a spatial arrangement that may aid in the sensitivity of the receptors to movements, but additional research is required.
The visual system of the shovelnose is more extensive and developed than other Elasmobranchii
Elasmobranchii
Elasmobranchii is a subclass of Chondrichthyes or cartilaginous fish, that includes the sharks and the rays and skates .-Evolution:...
, with multiple large projections connecting to the brain. Almost the entire dorsal and ventral hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
is connected to the visual system, but still maintains a similar lack of differentiation as with sharks.
This species has had one documented case of an attack on a diver when a male guitarfish was interrupted during mating. Because of the tooth structure of the guitarfish, this attack could have resulted in a "gumming" at worst.