Project 182: T. A. Demere, M. R. McGowen, A. Berta, J. G. Gatesy. 2008. Morphological and molecular evidence for a stepwise transition from teeth to baleen in mysticete whales. Systematic Biology. 57 (1):15-37.
Abstract
The origin of baleen in mysticete whales represents a major transition in the phylogenetic history of Cetacea. This key specialization, a keratinous sieve that enables filter-feeding, permitted exploitation of a new ecological niche and heralded the evolution of modern baleen-bearing whales, the largest animals on Earth. To date, all formally described mysticete fossils conform to two types: toothed species from Oligocene-age rocks (approximately 24 to 34 million years old) and toothless species that presumably utilized baleen to feed (Recent to approximately 30 million years old). Here, we show that several Oligocene toothed mysticetes have nutrient foramina and associated sulci on the lateral portions of their palates, homologous structures in extant mysticetes house vessels that nourish baleen. The simultaneous occurrence of teeth and nutrient foramina implies that both teeth and baleen were present in these early mysticetes. Phylogenetic analyses of a supermatrix that includes extinct taxa and new data for 11 nuclear genes consistently resolve relationships at the base of Mysticeti. The combined data set of 27,340 characters supports a stepwise transition from a toothed ancestor, to a mosaic intermediate with both teeth and baleen, to modern baleen whales that lack an adult dentition but retain developmental and genetic evidence of their ancestral toothed heritage. Comparative sequence data for ENAM (enamelin) and AMBN (ameloblastin) indicate that enamel-specific loci are present in Mysticeti but have degraded to pseudogenes in this group. The dramatic transformation in mysticete feeding anatomy documents an apparently rare, stepwise mode of evolution in which a composite phenotype bridged the gap between primitive and derived morphologies; a combination of fossil and molecular evidence provides a multifaceted record of this macroevolutionary pattern.Read the article »
Project DOI: 10.7934/P182, http://dx.doi.org/10.7934/P182
This project contains | Matrices |
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Download Project SDD File | Total scored cells: 2891 Total media associated with cells: 0 Total labels associated with cell media: 0 |
Characters | |
Total characters: 115 Total characters with associated media: 0 Total characters with media with labels: 0 Total character states: 301 Total character states with associated media: 0 Total character states with media with labels:0 Total unordered/ordered characters:115/0 |
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MorphoBank Project 182
MorphoBank Project 182
- Creation Date:
07 January 2008 - Publication Date:
07 January 2008 - Project views: 34399
- Matrix downloads: 40
This research
supported by
Authors' Institutions
- San Diego State University
- University of California Riverside
- San Diego Natural History Museum
Members
member name | taxa | specimens | media | media notes | chars | character
| cell scorings (scored, NPA, "-") | cell
| rules | ||||||||||
Annalisa Berta Project Administrator | 79 | 0 | 0 | 0 | 115 | 0 | 0 | 0 | 2891 (2891, 0, 0) | 0 | 0 | 0 | 0 | ||||||
MorphoBank Curator Full membership | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 | 0 | ||||||
Tom Demere Full membership | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 | 0 | ||||||
John Gatesy Full membership | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 | 0 | ||||||
Michael McGowen Full membership | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 | 0 |
Taxonomic Overview for Matrix 'M481' (50 Taxa)
taxon | unscored cells |
scored cells |
no cell support |
NPA cells |
"-" cells | cell images | labels on cell images |
member access |
[1] New taxon Last Modified in 12/05/13 | 115 | 0 | 0 | 0 | 0 | 0 | 0 | 5 |
[2] Physeter macrocephalus Last Modified in 12/05/13 | 22 | 93 | 93 | 0 | 0 | 0 | 0 | 5 |
[3] Ziphiidae Last Modified in 12/05/13 | 19 | 96 | 96 | 0 | 0 | 0 | 0 | 5 |
[4] Megaptera novaeangliae Last Modified in 12/05/13 | 19 | 96 | 96 | 0 | 0 | 0 | 0 | 5 |
[5] Balaenoptera physalus Last Modified in 12/05/13 | 19 | 98 | 96 | 0 | 0 | 0 | 0 | 5 |
[6] Balaenoptera musculus Last Modified in 12/05/13 | 19 | 96 | 96 | 0 | 0 | 0 | 0 | 5 |
[7] Balaenoptera borealis Last Modified in 12/05/13 | 19 | 96 | 96 | 0 | 0 | 0 | 0 | 5 |
[8] Balaenoptera edeni brydei Last Modified in 12/05/13 | 19 | 97 | 96 | 0 | 0 | 0 | 0 | 5 |
[9] Balaenoptera bonaerensis Last Modified in 12/05/13 | 20 | 95 | 95 | 0 | 0 | 0 | 0 | 5 |
[10] Balaenoptera acutorostrata Last Modified in 12/05/13 | 19 | 97 | 96 | 0 | 0 | 0 | 0 | 5 |
[11] Eschrichtius robustus Last Modified in 12/05/13 | 19 | 97 | 96 | 0 | 0 | 0 | 0 | 5 |
[12] Caperea marginata Last Modified in 12/05/13 | 20 | 96 | 95 | 0 | 0 | 0 | 0 | 5 |
[13] Balaena mysticetus Last Modified in 12/05/13 | 20 | 96 | 95 | 0 | 0 | 0 | 0 | 5 |
[14] Eubalaena Last Modified in 12/05/13 | 20 | 95 | 95 | 0 | 0 | 0 | 0 | 5 |
[15] Mammalodon colliveri Last Modified in 12/05/13 | 60 | 55 | 55 | 0 | 0 | 0 | 0 | 5 |
[16] Aetiocetus weltoni Last Modified in 12/05/13 | 40 | 75 | 75 | 0 | 0 | 0 | 0 | 5 |
[17] Aetiocetus cotylalveus Last Modified in 12/05/13 | 51 | 64 | 64 | 0 | 0 | 0 | 0 | 5 |
[18] Aetiocetus polydentatus Last Modified in 12/05/13 | 40 | 75 | 75 | 0 | 0 | 0 | 0 | 5 |
[19] Chonecetus goedertorum Last Modified in 12/05/13 | 46 | 69 | 69 | 0 | 0 | 0 | 0 | 5 |
[20] Eomysticetus whitmorei Last Modified in 12/05/13 | 44 | 71 | 71 | 0 | 0 | 0 | 0 | 5 |
[21] Aglaocetus patulus Last Modified in 12/05/13 | 56 | 59 | 59 | 0 | 0 | 0 | 0 | 5 |
[22] Cetotherium rathkii Last Modified in 12/05/13 | 74 | 41 | 41 | 0 | 0 | 0 | 0 | 5 |
[23] Cophocetus oregonensis Last Modified in 12/05/13 | 40 | 75 | 75 | 0 | 0 | 0 | 0 | 5 |
[24] Diorocetus hiatus Last Modified in 12/05/13 | 36 | 80 | 79 | 0 | 0 | 0 | 0 | 5 |
[25] Isanacetus laticephalus Last Modified in 12/05/13 | 52 | 64 | 63 | 0 | 0 | 0 | 0 | 5 |
[26] Mixocetus elysius Last Modified in 12/05/13 | 62 | 53 | 53 | 0 | 0 | 0 | 0 | 5 |
[27] Parietobalaena palmeri Last Modified in 12/05/13 | 37 | 80 | 78 | 0 | 0 | 0 | 0 | 5 |
[28] Pelocetus calvertensis Last Modified in 12/05/13 | 32 | 83 | 83 | 0 | 0 | 0 | 0 | 5 |
[29] Balaenoptera Last Modified in 12/05/13 | 42 | 73 | 73 | 0 | 0 | 0 | 0 | 5 |
[30] SDSNH 90517 Last Modified in 12/05/13 | 30 | 88 | 85 | 0 | 0 | 0 | 0 | 5 |
[31] Megaptera Last Modified in 12/05/13 | 65 | 50 | 50 | 0 | 0 | 0 | 0 | 5 |
[32] Parabalaenoptera baulinensis Last Modified in 12/05/13 | 56 | 59 | 59 | 0 | 0 | 0 | 0 | 5 |
[33] Agorophius Last Modified in 12/05/13 | 59 | 57 | 56 | 0 | 0 | 0 | 0 | 5 |
[34] Squalodon calvertensis Last Modified in 12/05/13 | 48 | 67 | 67 | 0 | 0 | 0 | 0 | 5 |
[35] Zygorhiza kochii Last Modified in 12/05/13 | 24 | 91 | 91 | 0 | 0 | 0 | 0 | 5 |
[36] Janjucetus hunderi Last Modified in 12/05/13 | 54 | 61 | 61 | 0 | 0 | 0 | 0 | 5 |
[37] P macrocephalus Last Modified in 12/05/13 | 102 | 13 | 13 | 0 | 0 | 0 | 0 | 5 |
[38] M novaeangliae Last Modified in 12/05/13 | 102 | 13 | 13 | 0 | 0 | 0 | 0 | 5 |
[39] B physalus Last Modified in 12/05/13 | 102 | 13 | 13 | 0 | 0 | 0 | 0 | 5 |
[40] B musculus Last Modified in 12/05/13 | 102 | 13 | 13 | 0 | 0 | 0 | 0 | 5 |
[41] B borealis Last Modified in 12/05/13 | 102 | 13 | 13 | 0 | 0 | 0 | 0 | 5 |
[42] B edeni brydei Last Modified in 12/05/13 | 115 | 0 | 0 | 0 | 0 | 0 | 0 | 5 |
[43] B bonaerensis Last Modified in 12/05/13 | 102 | 13 | 13 | 0 | 0 | 0 | 0 | 5 |
[44] B acutorostrata Last Modified in 12/05/13 | 104 | 11 | 11 | 0 | 0 | 0 | 0 | 5 |
[45] E robustus Last Modified in 12/05/13 | 102 | 13 | 13 | 0 | 0 | 0 | 0 | 5 |
[46] C marginata Last Modified in 12/05/13 | 102 | 13 | 13 | 0 | 0 | 0 | 0 | 5 |
[47] B mysticetus Last Modified in 12/05/13 | 102 | 13 | 13 | 0 | 0 | 0 | 0 | 5 |
[48] Eubalaena sp Last Modified in 12/05/13 | 102 | 13 | 13 | 0 | 0 | 0 | 0 | 5 |
[49] END Last Modified in 12/05/13 | 114 | 1 | 1 | 0 | 0 | 0 | 0 | 5 |
[50] BEGIN Last Modified in 12/05/13 | 104 | 11 | 11 | 0 | 0 | 0 | 0 | 5 |
Project views
type | number of views | Individual items viewed (where applicable) |
Total project views | 34399 | |
Project overview | 4063 | |
Matrix views | 2503 | Matrix landing page (2121 views); Mysticete Supermatirx (382 views); |
Media views | 6224 | Media search (5352 views); M85691 (872 views); |
Specimen list | 3138 | |
Taxon list | 15670 | |
Documents list | 1595 | |
Bibliography | 1204 | |
Folio views | 2 | Folio list (1 view); Character descriptions (1 view); |
Project downloads
type | number of downloads | Individual items downloaded (where applicable) |
Total downloads from project | 445 | |
Matrix downloads | 40 | Mysticete Supermatirx (40 downloads); |
Project downloads | 393 | |
Document downloads | 12 | Demere et al. Dental (2 downloads); Demere et al. Supermatrix (7 downloads); Morphological_characters.pdf (1 download); Morph_part_tnt_matrix_order_b.tnt (1 download); Most parsimonious trees (1 download); |