I will briefly review the history of the bill sense of the platypus, a sophisticated combination of electroreception and mechanoreception that coordinates information about aquatic prey provided from the bill skin mechanoreceptors and electroreceptors, and provide an evolutionary account of electroreception in the three extant species of monotreme (and what can be inferred of their ancestors). Electroreception in monotremes is compared and contrasted with the extensive body of work on electric fish, and an account of the central processing of mechanoreceptive and electroreceptive input in the somatosensory neocortex of the platypus, where sophisticated calculations seem to enable a complete three-dimensional fix on prey, is given.

Bell
C. C.
,
Han
V. Z.
,
Sugawara
Y.
,
Grant
K.
(
1999
).
Synaptic plasticity in the mormyrid electrosensory lobe
.
J. Exp. Biol
202
,
1339
–.
Elston
G. N.
,
Manger
P. R.
,
Pettigrew
J. D.
(
1999
).
Morphology of pyramidal neurones in cytochrome oxidase modules of the S-1 bill representation of the platypus
.
Brain Behav. Evol
53
,
87
–.
Fjällbrant
T. T.
,
Manger
P. R.
,
Pettigrew
J. D.
(
1998
).
Some related aspects of platypus electroreception: temporal integration behaviour, electroreceptive thresholds and directionality of the bill acting as an antenna
.
Phil. Trans. R. Soc. Lond. B
353
,
1211
–.
Griffiths
M.
(
1998
).
Platypus research 1798—1998. (Preface)
.
Phil. Trans. R. Soc. Lond. B
353
,
1059
–.
Home
E.
(
1802
).
A description of the anatomy of Ornithorhynchus paradoxus
.
Phil. Trans. R. Soc. Lond
92
,
67
–.
Hopkins
C. D.
(
1999
).
Design features for electric communication
.
J. Exp. Biol
202
,
1217
–.
Kalmijn
A. J.
(
1997
).
Electric and near-field acoustic detection, a comparative study
.
Acta Physiol. Scand
161
,
638
–.
Kawasaki
M.
(
1997
).
Sensory hyperacuity in the jamming avoidance response of weakly electric fish
.
Curr. Opin. Neurobiol
7
,
473
–.
Manger
P. R.
,
Calford
M. B.
,
Pettigrew
J. D.
(
1996
).
Properties of electrosensory neurons in the cortex of the platypus (Ornithorhyncus anatinus): implications for processing of electrosensory stimuli
.
Proc. R. Soc. Lond. B
263
,
611
–.
Manger
P. R.
,
Keast
J. R.
,
Pettigrew
J. D.
,
Troutt
L.
(
1998
).
Distribution and putative function of the autonomic nerve fibres in the bill skin of the platypus (Ornithorhynchus anatinus)
.
Phil. Trans. R. Soc. Lond. B
353
,
1159
–.
Manger
P. R.
,
Pettigrew
J. D.
(
1995
).
Electroreception and the feeding behaviour of the platypus (Ornithorhyncus anatinus: Monotremata: Mammalia)
.
Phil. Trans. R. Soc. Lond. B
347
,
359
–.
Manger
P. R.
,
Pettigrew
J. D.
(
1996
).
Ultrastructure, number, distribution and innervation of electroreceptors and mechanoreceptor organs in the bill skin of the platypus, Ornithorhynchus anatinus
.
Brain Behav. Evol
48
,
27
–.
Montgomery
J. C.
,
Bodznick
D.
(
1999
).
Signals and noise in the elasmobranch electrosensory system
.
J. Exp. Biol
202
,
1349
–.
Musser
A. M.
,
Archer
M.
(
1998
).
New information about the skull and dentary of the Miocene platypus Obduron dicksoni and a discusion of ornithorhynchid relationships
.
Phil. Trans. R. Soc. Lond. B
353
,
1063
–.
Pettigrew
J. D.
,
Manger
P. R.
,
Fine
S. L. B.
(
1998
).
The sensory world of the platypus
.
Phil. Trans. R. Soc. Lond. B
353
,
1199
–.
Proske
U.
,
Gregory
J. E.
,
Iggo
A.
(
1998
).
Sensory receptors in monotremes
.
Phil. Trans. R. Soc. Lond. B
353
,
1187
–.
Scheich
H.
,
Langner
G.
,
Tidemann
C.
,
Coles
R. B.
,
Guppy
A.
(
1986
).
Electroreception and electrolocation in platypus
.
Nature
319
,
401
–.
Siegel
J. M.
,
Manger
P. R.
,
Nienhuis
R.
,
Fahringer
H. M.
,
Pettigrew
J. D.
(
1996
).
The echidna Tachyglossus aculeatus 1454combines REM and nonREM aspects in a single sleep state: implications for the evolution of sleep
.
J. Neurosci
15
,
3500
–.
Siegel
J. M.
,
Manger
P. R.
,
Nienhuis
R.
,
Fahringer
H. M.
,
Pettigrew
J. D.
(
1998
).
Monotremes and the evolution of rapid eye movement sleep
.
Phil. Trans. R. Soc. Lond. B
353
,
1147
–.
von der Emde
G.
(
1999
).
Active electrolocation of objects in weakly electric fish
.
J. Exp. Biol
202
,
1205
–.
Wald
G.
,
Rayport
S.
(
1977
).
Vision in annelid worms
.
Science
196
,
1434
–.
Whittington
R. J.
(
1991
).
The survival of platypuses in captivity
.
Aust. Vet. J
68
,
32
–.
Wilkens
L. A.
,
Russell
D. F.
,
Pei
X.
,
Gurgens
C.
(
1997
).
The paddlefish rostrum functions as an electrosensory antenna in plankton feeding
.
Proc. R. Soc. Lond. B
264
,
1724
–.
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