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Electrosensitive spatial vectors in elasmobranch fishes: implications for source localization.

Rivera-Vicente AC, Sewell J, Tricas TC - PLoS ONE (2011)

Bottom Line: The MAN canals of all species project in anterior or posterior directions behind the mouth and likely coordinate prey capture.Vertical elevation was greatest in the BUC of the sandbar shark, restricted by the hammerhead cephalofoil and extremely limited in the dorsoventrally flattened stingray.These results are consistent with the functional subunit hypothesis that predicts specialized ampullary functions for processing of weak dipole and geomagnetic induced fields, and provides an anatomical basis for future experiments on central processing of different forms of relevant electric stimuli.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America.

ABSTRACT
The electrosense of sharks and rays is used to detect weak dipole-like bioelectric fields of prey, mates and predators, and several models propose a use for the detection of streaming ocean currents and swimming-induced fields for geomagnetic orientation. We assessed pore distributions, canal vectors, complementarity and possible evolutionary divergent functions for ampullary clusters in two sharks, the scalloped hammerhead (Sphyrna lewini) and the sandbar shark (Carcharhinus plumbeus), and the brown stingray (Dasyatis lata). Canal projections were determined from measured coordinates of each electrosensory pore and corresponding ampulla relative to the body axis. These species share three ampullary groups: the buccal (BUC), mandibular (MAN) and superficial ophthalmic (SO), which is subdivided into anterior (SOa) and posterior (SOp) in sharks. The stingray also has a hyoid (HYO) cluster. The SOp in both sharks contains the longest (most sensitive) canals with main projections in the posterior-lateral quadrants of the horizontal plane. In contrast, stingray SO canals are few and short with the posterior-lateral projections subsumed by the HYO. There was strong projection coincidence by BUC and SOp canals in the posterior lateral quadrant of the hammerhead shark, and laterally among the stingray BUC and HYO. The shark SOa and stingray SO and BUC contain short canals located anterior to the mouth for detection of prey at close distance. The MAN canals of all species project in anterior or posterior directions behind the mouth and likely coordinate prey capture. Vertical elevation was greatest in the BUC of the sandbar shark, restricted by the hammerhead cephalofoil and extremely limited in the dorsoventrally flattened stingray. These results are consistent with the functional subunit hypothesis that predicts specialized ampullary functions for processing of weak dipole and geomagnetic induced fields, and provides an anatomical basis for future experiments on central processing of different forms of relevant electric stimuli.

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Polar plots of canal projections in three planes of the electrosensory ampullary array of the scalloped hammerhead shark, Sphyrna lewini.Plots show canal length (cm) vs. canal orientation angle in the horizontal, sagittal and transverse planes for each ampulla group (BUC  =  buccal; SOa  =  superficial ophthalmic anterior; SOp  =  superficial ophthalmic posterior; MAN  =  mandibular). Projections of ventral and dorsal canals are indicated with red and black symbols, respectively. Projections are shown for both left (filled symbols) and right (open symbols) ampullary clusters. Reference directions for each plane are horizontal: 0° =  anterior (A), 90° =  left (L), 180° =  posterior (P), 270° =  right (R); sagittal: 0° =  anterior (A), 90° =  ventral (V), 180° =  posterior (P), 270° =  dorsal (D); transverse: 0° =  dorsal (D), 90° =  left (L), 180° =  ventral (V), 270° =  right (R).
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pone-0016008-g005: Polar plots of canal projections in three planes of the electrosensory ampullary array of the scalloped hammerhead shark, Sphyrna lewini.Plots show canal length (cm) vs. canal orientation angle in the horizontal, sagittal and transverse planes for each ampulla group (BUC  =  buccal; SOa  =  superficial ophthalmic anterior; SOp  =  superficial ophthalmic posterior; MAN  =  mandibular). Projections of ventral and dorsal canals are indicated with red and black symbols, respectively. Projections are shown for both left (filled symbols) and right (open symbols) ampullary clusters. Reference directions for each plane are horizontal: 0° =  anterior (A), 90° =  left (L), 180° =  posterior (P), 270° =  right (R); sagittal: 0° =  anterior (A), 90° =  ventral (V), 180° =  posterior (P), 270° =  dorsal (D); transverse: 0° =  dorsal (D), 90° =  left (L), 180° =  ventral (V), 270° =  right (R).

Mentions: The hammerhead shark shares common clusters with the sandbar shark and has distinct projections in dorsal and ventral surfaces (see Movie S1). The BUC cluster is located on the lateral aspect of the cephalofoil, medial to the eye and caudal to the nares (Fig. 2B). A left BUC cluster contained 297 canals of which 37% project to dorsal and 63% project to ventral pores (Table 1). Canal lengths for the BUC included the shortest found in this species (1.10 cm) and up to 9.30 cm. Each BUC cluster has dorsal canals that sweep in a 270° arc in the horizontal plane from the anterior to lateral to posterior to medial directions (Fig. 5). Longest dorsal canals are in the posterior lateral direction at an azimuth of 135° alpha in the horizontal plane (Fig. 5). Ventral projections show a similar prominent posterior lateral projection but with shorter canals. In total, the BUC dorsal projections cover a near 360° azimuth with maximum elevation near 60° ϕ and a dip to below 30° ϕ in the anterior direction (Fig. 4). Ventral BUC canals are relatively short, have restricted posterior lateral projections and show maximum elevation near −60° ϕ (Fig. 4).


Electrosensitive spatial vectors in elasmobranch fishes: implications for source localization.

Rivera-Vicente AC, Sewell J, Tricas TC - PLoS ONE (2011)

Polar plots of canal projections in three planes of the electrosensory ampullary array of the scalloped hammerhead shark, Sphyrna lewini.Plots show canal length (cm) vs. canal orientation angle in the horizontal, sagittal and transverse planes for each ampulla group (BUC  =  buccal; SOa  =  superficial ophthalmic anterior; SOp  =  superficial ophthalmic posterior; MAN  =  mandibular). Projections of ventral and dorsal canals are indicated with red and black symbols, respectively. Projections are shown for both left (filled symbols) and right (open symbols) ampullary clusters. Reference directions for each plane are horizontal: 0° =  anterior (A), 90° =  left (L), 180° =  posterior (P), 270° =  right (R); sagittal: 0° =  anterior (A), 90° =  ventral (V), 180° =  posterior (P), 270° =  dorsal (D); transverse: 0° =  dorsal (D), 90° =  left (L), 180° =  ventral (V), 270° =  right (R).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3020962&req=5

pone-0016008-g005: Polar plots of canal projections in three planes of the electrosensory ampullary array of the scalloped hammerhead shark, Sphyrna lewini.Plots show canal length (cm) vs. canal orientation angle in the horizontal, sagittal and transverse planes for each ampulla group (BUC  =  buccal; SOa  =  superficial ophthalmic anterior; SOp  =  superficial ophthalmic posterior; MAN  =  mandibular). Projections of ventral and dorsal canals are indicated with red and black symbols, respectively. Projections are shown for both left (filled symbols) and right (open symbols) ampullary clusters. Reference directions for each plane are horizontal: 0° =  anterior (A), 90° =  left (L), 180° =  posterior (P), 270° =  right (R); sagittal: 0° =  anterior (A), 90° =  ventral (V), 180° =  posterior (P), 270° =  dorsal (D); transverse: 0° =  dorsal (D), 90° =  left (L), 180° =  ventral (V), 270° =  right (R).
Mentions: The hammerhead shark shares common clusters with the sandbar shark and has distinct projections in dorsal and ventral surfaces (see Movie S1). The BUC cluster is located on the lateral aspect of the cephalofoil, medial to the eye and caudal to the nares (Fig. 2B). A left BUC cluster contained 297 canals of which 37% project to dorsal and 63% project to ventral pores (Table 1). Canal lengths for the BUC included the shortest found in this species (1.10 cm) and up to 9.30 cm. Each BUC cluster has dorsal canals that sweep in a 270° arc in the horizontal plane from the anterior to lateral to posterior to medial directions (Fig. 5). Longest dorsal canals are in the posterior lateral direction at an azimuth of 135° alpha in the horizontal plane (Fig. 5). Ventral projections show a similar prominent posterior lateral projection but with shorter canals. In total, the BUC dorsal projections cover a near 360° azimuth with maximum elevation near 60° ϕ and a dip to below 30° ϕ in the anterior direction (Fig. 4). Ventral BUC canals are relatively short, have restricted posterior lateral projections and show maximum elevation near −60° ϕ (Fig. 4).

Bottom Line: The MAN canals of all species project in anterior or posterior directions behind the mouth and likely coordinate prey capture.Vertical elevation was greatest in the BUC of the sandbar shark, restricted by the hammerhead cephalofoil and extremely limited in the dorsoventrally flattened stingray.These results are consistent with the functional subunit hypothesis that predicts specialized ampullary functions for processing of weak dipole and geomagnetic induced fields, and provides an anatomical basis for future experiments on central processing of different forms of relevant electric stimuli.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America.

ABSTRACT
The electrosense of sharks and rays is used to detect weak dipole-like bioelectric fields of prey, mates and predators, and several models propose a use for the detection of streaming ocean currents and swimming-induced fields for geomagnetic orientation. We assessed pore distributions, canal vectors, complementarity and possible evolutionary divergent functions for ampullary clusters in two sharks, the scalloped hammerhead (Sphyrna lewini) and the sandbar shark (Carcharhinus plumbeus), and the brown stingray (Dasyatis lata). Canal projections were determined from measured coordinates of each electrosensory pore and corresponding ampulla relative to the body axis. These species share three ampullary groups: the buccal (BUC), mandibular (MAN) and superficial ophthalmic (SO), which is subdivided into anterior (SOa) and posterior (SOp) in sharks. The stingray also has a hyoid (HYO) cluster. The SOp in both sharks contains the longest (most sensitive) canals with main projections in the posterior-lateral quadrants of the horizontal plane. In contrast, stingray SO canals are few and short with the posterior-lateral projections subsumed by the HYO. There was strong projection coincidence by BUC and SOp canals in the posterior lateral quadrant of the hammerhead shark, and laterally among the stingray BUC and HYO. The shark SOa and stingray SO and BUC contain short canals located anterior to the mouth for detection of prey at close distance. The MAN canals of all species project in anterior or posterior directions behind the mouth and likely coordinate prey capture. Vertical elevation was greatest in the BUC of the sandbar shark, restricted by the hammerhead cephalofoil and extremely limited in the dorsoventrally flattened stingray. These results are consistent with the functional subunit hypothesis that predicts specialized ampullary functions for processing of weak dipole and geomagnetic induced fields, and provides an anatomical basis for future experiments on central processing of different forms of relevant electric stimuli.

Show MeSH
Related in: MedlinePlus