Adult galliform birds (e.g. chickens) exhibit a relatively small telencephalon and a proportionately large optic tectum compared with parrots and songbirds. We previously examined the embryonic origins of these adult species differences and found that the optic tectum is larger in quail than in parakeets and songbirds at early stages of development, prior to tectal neurogenesis onset. The aim of this study was to determine whether a proportionately large presumptive tectum is a primitive condition within birds or a derived feature of quail and other galliform birds. To this end, we examined embryonic brains of several avian species (emus, parrots, songbirds, waterfowl, galliform birds), reptiles (3 lizard species, alligators, turtles) and a monotreme (platypuses). Brain region volumes were estimated from serial Nissl-stained sections. We found that the embryos of galliform birds and lizards exhibit a proportionally larger presumptive tectum than all the other examined species. The presumptive tectum of the platypus is unusually small. The most parsimonious interpretation of these data is that the expanded embryonic tectum of lizards and galliform birds is a derived feature in both of these taxonomic groups.

Keywords:
Bird, Development, Mammal, Monotreme, Reptile, Tectum, Vision
1.
Araki I, Nakamura H (1999): Engrailed defines the position of dorsal di-mesencephalic boundary by repressing diencephalic fate. Development 126:5127–5135.
2.
Barton RA, Harvey PH (2000): Mosaic evolution of brain structure in mammals. Nature 405:1055–1058.
3.
Boire D, Baron G (1994): Allometric comparison of brain and main brain subdivisions in birds. J Brain Res 35:49–66.
4.
Carter AM (2008): Sources of comparative studies of Placentation. 1. Embryological collections. Placenta 29:95–98.
5.
Charvet CJ, Striedter GF (2009a): Developmental origins of mosaic brain evolution: morphometric analysis of the developing zebra finch brain. J Comp Neurol 514:203–213.
6.
Charvet CJ, Striedter GF (2009b): Developmental basis for telencephalon expansion in waterfowl: enlargement prior to neurogenesis. Proc Biol Sci 276:3241–3247.
7.
Charvet CJ, Striedter GF (2009c): Neurogenesis timing is conserved across precocial avian specie. Soc Neurosci Abstr 225:6.
8.
Clancy B, Darlington RB, Finlay BL (2001): Translating developmental time across mammalian species. Neuroscience 105:7–17.
9.
Comer C, Grobstein P (1981): Organization of sensory inputs to the midbrain of the frog Rana pipiens. J Comp Physiol 142:161–168.
10.
Ebinger P, Löhmer R (1987): A volumetric comparison of brains between greylag geese (Anser anser L.) and domestic geese. J Hirnforsch 3:291–299.
11.
Finlay BL, Darlington RB (1995): Linked regularities in the development and evolution of mammalian brains. Science 268:1578–1584.
12.
Finlay BL, Darlington RB, Nicastro N (2001): Developmental structure in brain evolution. Behav Brain Sci 24:263–308.
13.
Finlay BL, Hersman MN, Darlington RB (1998): Patterns of vertebrate neurogenesis and the paths of vertebrate evolution. Brain Behav Evol 52:232–242.
14.
Ferguson MWJ (1985): Reproductive biology and embryology of the crocodilians; in Gans C, Billet F Maderson PFA (eds): Biology of the Reptilia: Development A. New York, Wiley, vol 14, pp 329–491.
15.
Giere P, Zeller U (2005): Transfer of the Hubrecht Laboratory Collection from Utrecht to the Museum für Naturkunde, Berlin. Placenta 26:A15.
16.
Hackett SJ, Kimball RT, Reddy S, Bowie RC, Braun EL, Braun MJ, Chojnowski JL, Cox WA, Han KL, Harshman J, Huddleston CJ, Marks BD, Miglia KJ, Moore WS, Sheldon FH, Steadman DW, Witt CC, Yuri T (2008): A phylogenomic study of birds reveals their evolutionary history. Science 320:1763–1768.
17.
Iwaniuk AN, Dean C, Nelson JE (2004): A mosaic pattern characterizes the evolution of the avian brain. Proc R Soc Lond B Suppl 271:148–151.
18.
Iwaniuk AN, Hurd PL (2005): The evolution of cerebrotypes in birds. Brain Behav Evol 65:215–230.
19.
Matsunaga E, Araki I, Nakamura H (2001): Role of Pax3/7 in the tectum regionalization. Development 128:4069–4077.
20.
Menuet A, Alunni A, Joly JS, Jeffrey WR, and Rétaux S (2007): Expanded expression of Sonic Hedgehog in Astyanax cavefish: multiple consequences on forebrain development and evolution. Development 134:845–855.
21.
Meyer A, Zardoya R (2003): Recent advances in the (molecular) phylogeny of vertebrates. Ann Rev Ecol Evol Syst 34:311–338.
22.
Nakamura H (2001): Regionalization of the optic tectum: combinations of gene expression that define the tectum. Trends Neurosci 24:32–39.
23.
Pettigrew JD, Manger PR, Fine SLB (1998): The sensory world of the platypus. Phil Trans R Soc Lond B 353:1199–1210.
24.
Rasband WS (1997–2007): ImageJ. Bethesda, National Institutes of Health.
25.
Reep RL, Finlay BL, Darlington RB (2007): The limbic system in mammalian brain evolution. Brain Behav Evol 70:57–70.
26.
Rétaux S, Pottin K, Alunni A (2008): Shh and forebrain evolution in the blind cavefish Astyanax mexicanus. Biol Cell 100:139–147.
27.
Richardson MK, Narraway J (1999): A treasure house of comparative embryology. Int J Dev Biol 43:591–602.
28.
Stephan H, Frahm H, Baron G (1981): New and revised data on volumes of brain structures on insectivores and primates. Folia Primatol 35:1–29.
29.
Striedter GF, Charvet CJ (2008): Developmental origins of species differences in telencephalon and tectum size: morphometric comparisons between a parakeet (Melopsittacus undulatus) and a quail (Colinus virgianus). J Comp Neurol 507:1663–1675.
30.
Yopak KE, Lisney TJ, Collin SP, Montgomery JC (2007): Variation in brain organization and cerebellar foliation in chondrichthyans: sharks and holocephalans. Brain Behav Evol 69:280–300.
© 2010 S. Karger AG, Basel
2010
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.