Abstract
Baleen whales are considered underencephalized mammals due to their reduced brain size with respect to their body size (encephalization quotient [EQ] << 1). Despite their low EQ, mysticetes exhibit complex behavioral patterns in terms of motor abilities, vocal repertoire, and cultural learning. Very scarce information is available about the morphological evolution of the brain in this group; this makes it difficult to investigate the historical changes in brain shape and size in order to relate the origin of the complex mysticete behavioral repertoire to the evolution of specific neural substrates. Here, the first description of the virtual endocast of a fossil balaenopterid species, Marzanoptera tersillae from the Italian Pliocene, reveals an EQ of around 3, which is exceptional for baleen whales. The endocast showed a morphologically different organization of the brain in this fossil whale as the cerebral hemispheres are anteroposteriorly shortened, the cerebellum lacks the posteromedial expansion of the cerebellar hemispheres, and the cerebellar vermis is unusually reduced. The comparative reductions of the cerebral and cerebellar hemispheres suggest that the motor behavior of M. tersillae probably was less sophisticated than that exhibited by the extant rorqual and humpback species. The presence of an EQ value in this fossil species that is around 10 times higher than that of extant mysticetes opens new questions about brain evolution and provides new, invaluable information about the evolutionary path of morphological and size change in the brain of baleen whales.
References
1.
Arnold
P
, Marsh
H
, Heinsohn
G
. The occurrence of two forms of minke whales in East Australian waters with a description of external characters and skeleton of the diminutive and dwarf form
. Sci Rep Whales Res Inst
. 1987
;38
:1
–46
.0083-90862.
Arnold
PA
, Birtles
RA
, Sobtzik
S
, Matthews
M
, Dunstan
A
. Gulping behaviour in rorqual whales: underwater observations and functional interpretations
. Mem Queensl Mus
. 2005
;51
:309
–32
.0079-88353.
Bisconti
M
, Bosselaers
M
. A new balaenopterid species from the southern North Sea informs about phylogeny and taxonomy of Burtinopsis and Protororqualus (Cetacea, Mysticeti, Balaenopteridae)
. PeerJ
. 2020
;8
:e9570
. 2167-83594.
Bisconti
M
, Damarco
P
, Mao
S
, Pavia
M
, Carnevale
G
. The earliest baleen whale from the Mediterranean: large-scale implications of an early Miocene thalassotherian mysticete from Piedmont, Italy
. Pap Palaeontol
. 2021
a;7
(2
):1147
–66
. 2056-27995.
Bisconti
M
, Damarco
P
, Pavia
M
, Sorce
B
, Carnevale
G
. Marzanoptera tersillae, a new balaenopterid genus and species from the Pliocene of Piedmont, north-west Italy
. Zool J Linn Soc
. 2021
b;192
(4
):1253
–92
. 0024-40826.
Bisconti
M
, Damarco
P
, Tartarelli
G
, Pavia
M
, Carnevale
G
. A natural endocast of an early Miocene odontocete and its implications in cetacean brain evolution
. J Comp Neurol
. 2021
c Apr
;529
(6
):1198
–227
.
[PubMed]
1096-98617.
Bisconti
M
, Munsterman
DK
, Post
K
. A new balaenopterid whale from the late Miocene of the Southern North Sea Basin and the evolution of balaenopterid diversity (Cetacea, Mysticeti)
. PeerJ
. 2019
May
;7
:e6915
.
[PubMed]
2167-83598.
Bisconti
M
, Pellegrino
L
, Carnevale
G
. Evolution of gigantism in right and bowhead whales (Cetacea: Mysticeti: Balaenidae)
. Biol J Linn Soc Lond
. 2021
d;134
(2
):498
–524
. 0024-40669.
Boddy
AM
, McGowen
MR
, Sherwood
CC
, Grossman
LI
, Goodman
M
, Wildman
DE
. Comparative analysis of encephalization in mammals reveals relaxed constraints on anthropoid primate and cetacean brain scaling
. J Evol Biol
. 2012
May
;25
(5
):981
–94
.
[PubMed]
1420-910110.
Boessenecker
RW
, Ahmed
E
, Geisler
JH
(2017
): New records of the dolphin Albertocetus meffordorum (Odontoceti: Xenorophidae) from the lower Oligocene of South Carolina: Encephalization, sensory anatomy, postcranial morphology, and ontogeny of early odontocetes. PLoS One 12(11), e0186476. DOI: . 018647611.
Cozzi
B
, Huggenberger
S
, Oelschläger
H
. Anatomy of dolphins. Insights into body structure and function
. London
: Academic Press
; 2017
.12.
Dart
R
. The brain of the Zeuglodontidae (Cetacea)
. Proc Zool Soc Lond
. 1923
;1923
:615
–54
.0370-277413.
Evans
AR
, Jones
D
, Boyer
AG
, Brown
JH
, Costa
DP
, Ernest
SK
, et al The maximum rate of mammal evolution
. Proc Natl Acad Sci USA
. 2012
Mar
;109
(11
):4187
–90
.
[PubMed]
1091-649014.
Font
E
, García-Roa
R
, Pincheira-Donoso
D
, Carazo
P
. Rethinking the effects of body sizeon the study of brain size evolution
. Brain Behav Evol
. 2018
;219
:1
–14
.
[PubMed]
15.
Gingerich
PD
. Body weight and relative brain size (encephalization) in Eocene Archaeoceti (Cetacea)
. J Mamm Evol
. 2016
;23
(1
):17
–31
. 1064-755416.
Goldbogen
JA
, Calambokidis
J
, Shadwick
RE
, Oleson
EM
, McDonald
MA
, Hildebrand
JA
. Kinematics of foraging dives and lunge-feeding in fin whales
. J Exp Biol
. 2006
Apr
;209
(Pt 7
):1231
–44
.
[PubMed]
0022-094917.
Hammer
Ø
, Harper
DA
, Ryan
PD
. PAST: paleontological statistics software package for education and data analysis
. Palaeont Electr
. 2001
;4
(1
):9
.18.
Hanson
A
, Grisham
W
, Sheh
C
, Annese
J
, Ridgway
S
. Quantitative examination of the bottlenose dolphin cerebellum
. Anat Rec (Hoboken)
. 2013
Aug
;296
(8
):1215
–28
.
[PubMed]
1932-849419.
20.
Kirchner
T
, Wiley
DN
, Hazen
EL
, Parks
SE
, Torres
LG
, Friedlaender
AS
. Hierarchical foraging movement of humpback whales relative to the structure of their prey
. Mar Ecol Prog Ser
. 2018
;607
:237
–50
. 0171-863021.
Kitching
IJ
, Forey
PL
, Humphries
CJ
, Williams
DM
. Cladistics. The theory and practice of parsimony analysis
. Syst Ass Publ
. 1998
;11
:1
–228
.22.
Laland
KN
, Janik
VM
. The animal cultures debate
. Trends Ecol Evol
. 2006
Oct
;21
(10
):542
–7
.
[PubMed]
0169-534723.
Maddison
W
, Maddison
D
. (2019
): MESQUITE: A modular system for evolutionary analysis.
Retrieved from https://www.mesquiteproject.org/24.
Manger
PR
. An examination of cetacean brain structure with a novel hypothesis correlating thermogenesis to the evolution of a big brain
. Biol Rev Camb Philos Soc
. 2006
May
;81
(2
):293
–338
.
[PubMed]
1464-793125.
Marino
L
, McShea
DW
, Uhen
MD
. Origin and evolution of large brains in toothed whales
. Anat Rec A Discov Mol Cell Evol Biol
. 2004
Dec
;281
(2
):1247
–55
.
[PubMed]
1552-488426.
Marino
L
, Sol
D
, Toren
K
, Lefebvre
L
. Does diving limit brain size in cetaceans
. Mar Mamm Sci
. 2006
;22
(2
):413
–25
. 0824-046927.
Marino
L
. Cetacean brain evolution: multiplication generates complexity
. Int J Comp Psychol
. 2004
;17
:1
–16
.0889-366728.
McCurry
MR
, Marx
FG
, Evans
AR
, Park
T
, Pyenson
ND
, Kohno
N
, Castiglione
S
, Fitzgerald
EMG
(2021
): Brain size evolution in whales and dolphins: new data from fossil mysticetes.
Biol J Linnean Soc DOI: article/doi/29.
Mitchell
ED
. A new cetacean from the late Eocene La Meseta Formation, Seymour Island, Antarctic Peninsula
. Can J Fish Aquat Sci
. 1989
;46
(12
):2219
–35
. 0706-652X30.
Montgomery
SH
, Geisler
JH
, McGowen
MR
, Fox
C
, Marino
L
, Gatesy
J
. The evolutionary history of cetacean brain and body size
. Evolution
. 2013
Nov
;67
(11
):3339
–53
.
[PubMed]
1558-564631.
Oelschläger
HH
, Ridgway
SH
, Knauth
M
. Cetacean brain evolution: dwarf sperm whale (Kogia sima) and common dolphin (Delphinus delphis) - An investigation with high-resolution 3D MRI
. Brain Behav Evol
. 2010
;75
(1
):33
–62
.
[PubMed]
1421-974332.
Omura
H
, Kasuya
T
. Additional information on skeleton of the minke whale from the Antarctic
. Sci Rep Whales Res Inst
. 1976
;28
:57
–68
.0083-908633.
Omura
H
, Sakiura
H
. Studies on the little piked whale from the coast of Japan
. Sci Rep Whales Res Inst
. 1956
;11
:1
–37
.0083-908634.
Omura
H
. Osteological study of the little piked whale from the coast of Japan
. Sci Rep Whales Res Inst
. 1957
;12
:1
–21
.0083-908635.
Omura
H
. Osteological study of the minke whale from the Antarctic
. Sci Rep Whales Res Inst
. 1975
;27
:1
–36
.0083-908636.
Pilleri
G
, Gihr
M
. The central nervous system of mysticete and odontocete whales
. Invest Cet
. 1970
;3
:89
–128
.37.
Pilleri
G
. Morphologie des Gehirnes des “Southern Right Whale”, Eubalaena australis Desmoulins 1822 (Cetacea, Mysticeti, Balaenidae)
. Acta Zool
. 1964
;46
(3
):245
–72
. 0001-727238.
Pilleri
G
. Note on the cerebral anatomy of the humpback whale, Megaptera novaeangliae
. Rev Suisse Zool
. 1966
;73
:161
–5
. 0035-418X39.
Rendell
L
, Whitehead
H
. Culture in whales and dolphins
. Behav Brain Sci
. 2001
Apr
;24
(2
):309
–24
.
[PubMed]
0140-525X40.
Ridgway
SH
, Carlin
KP
, Van Alstyne
KR
, Hanson
AC
, Tarpley
RJ
. Comparison of dolphin’s body and brain measurements with four other groups of cetaceans reveals great diversity
. Brain Behav Evol
. 2016
;88
(3-4
):235
–57
.
[PubMed]
1421-974341.
Ries
FA
, Langworthy
OR
. A study of the surface structure of brain of the whale (Balaenoptera physalus and Physeter catodon)
. J Comp Neurol
. 1937
;68
(1
):1
–37
. 0021-996742.
Slater
GJ
, Goldbogen
JA
, Pyenson
ND
. Independent evolution of baleen whale gigantism linked to Plio-Pleistocene ocean dynamics
. Proc Biol Sci
. 2017
May
;284
(1855
):20170546
.
[PubMed]
1471-295443.
Smaers
JB
. Modeling the evolution of the cerebellum: from macroevolution to function
. Prog Brain Res
. 2014
;210
:193
–216
.
[PubMed]
1875-785544.
Tartarelli
G
, Bisconti
M
. Trajectories and constraints in brain evolution in primates and cetaceans
. Hum Evol
. 2007
;21
(3-4
):275
–87
. 0393-937545.
Van Essen
DC
, Donahue
CJ
, Glasser
MF
. Development and evolution of cerebral and cerebellar cortex
. Brain Behav Evol
. 2018
;91
(3
):158
–69
.
[PubMed]
1421-974346.
Zachos
J
, Pagani
M
, Sloan
L
, Thomas
E
, Billups
K
. Trends, rhythms, and aberrations in global climate 65 Ma to present
. Science
. 2001
Apr
;292
(5517
):686
–93
.
[PubMed]
0036-8075© 2021 S. Karger AG, Basel
2021
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.
