Project 5006: G. W. Rougier, S. Isaji, M. Manabe. 2007. An Early Cretaceous mammal from the Kuwajima Formation (Tetori Group), Japan, and a reassessment of triconodont phylogeny. Annals of Carnegie Museum. 76 (2):73.
Abstract
We describe here one of the oldest known Japanese mammals, a triconodont lower jaw from the Early Cretaceous Kuwajima Formation, Tetori Group, Japan. This mammal is recognized as the type of Hakusanodon archaeus, new genus, new species, and as closely related to Eurasian and North American Jurassic “amphilestid” triconodonts (Simpson 1925b–c; Jenkins and Crompton 1979; Sigogneau-Russell 2003a), a group of poorly understood early mammals. To better understand the relationships of Hakusanodon, we present an inclusive cladistic analysis of most triconodont mammals and relatives. Our analysis highlights the central role of triconodonts for early mammalian history and corroborates recent findings indicating that traditional groups of Mesozoic mammals such as Triconodonta (Jenkins and Crompton 1979), Amphilestidae (sensu Jenkins and Crompton 1979; McKenna and Bell 1997) and Symmetrodonta (sensu Lillegraven et al. 1979; McKenna and Bell 1997) are artificial. A dental pattern similar to that of “amphilestids” is generalized, playing a central role in mammalian dental evolution and being primitive for triconodontids and spalacotheriids, and therefore for the archaic members of the therian lineage. Australosphenidans (Luo et al. 2001a, 2003; Martin and Rauhut 2005), with fully reversed triangles in their lower dentitions (uppers are not known in any of them with the exception of monotremes), also are likely to have evolved from ancestors with an “amphilestid”/sym-metrodont-like dental morphology. The enigmatic Amphidon aequicrurius Simpson, 1925a, from the Jurassic of North America (Simpson 1925a) has been treated as related to acute angle symmetrodonts or to triconodonts. Re-study of the type and only specimen suggests that Amphidon Simpson, 1925a, is likely an old, worn-down “amphilestid” (Rougier et al. 2001), a conclusion also supported by the results of the cladistic analysis. Jeholodens jenkinsi Ji et al., 1999, postulated as a basal member of the triconodontid lineage, or eutriconodont (Ji et al. 1999), is more likely a generalized “amphilestid,” which makes this taxon more relevant for the understanding of the stem members of the therian lineage by providing a relatively complete out-group.Read the article »
Article DOI: 10.2992/0097-4463(2007)76[73:aecmft]2.0.co;2
Project DOI: 10.7934/P5006, http://dx.doi.org/10.7934/P5006
This project contains | Matrices |
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Download Project SDD File | Total scored cells: 1511 Total media associated with cells: 0 Total labels associated with cell media: 0 |
Characters | |
Total characters: 62 Total characters with associated media: 0 Total characters with media with labels: 0 Total character states: 143 Total character states with associated media: 0 Total character states with media with labels:0 Total unordered/ordered characters:62/0 |
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MorphoBank Project 5006
MorphoBank Project 5006
- Creation Date:
16 December 2023 - Publication Date:
28 December 2023 - Project views: 1769
- Matrix downloads: 1
This research
supported by
Authors' Institutions
- Natural History Museum and Institute, Chiba, Chiba Prefecture
- University of Louisville
- National Museum of Science and Nature, Tokyo, Japan
Members
member name | taxa | specimens | media | chars | character
| cell scorings (scored, NPA, "-") | cell
| rules | ||||||
Shreya Jariwala Project Administrator | 28 | 6 | 6 | 62 | 0 | 0 | 1511 (1511, 0, 0) | 0 | 0 | 0 |
Taxonomic Overview for Matrix 'M29587' (28 Taxa)
taxon | unscored cells |
scored cells |
no cell support |
NPA cells |
"-" cells | cell images | labels on cell images |
member access |
[1] † Morganucodon Last Modified in 12/16/23 | 0 | 62 | 62 | 0 | 0 | 0 | 0 | 1 |
[2] † Erythrotherium Last Modified in 12/16/23 | 3 | 60 | 59 | 0 | 0 | 0 | 0 | 1 |
[3] † Megazostrodon Last Modified in 12/16/23 | 1 | 61 | 61 | 0 | 0 | 0 | 0 | 1 |
[4] † Kuehneotherium Last Modified in 12/16/23 | 6 | 58 | 56 | 0 | 0 | 0 | 0 | 1 |
[5] † Woutersia Last Modified in 12/16/23 | 37 | 27 | 25 | 0 | 0 | 0 | 0 | 1 |
[6] † Dinnetherium Last Modified in 12/16/23 | 0 | 62 | 62 | 0 | 0 | 0 | 0 | 1 |
[7] † Haldanodon Last Modified in 12/16/23 | 3 | 60 | 59 | 0 | 0 | 0 | 0 | 1 |
[8] † Docodon Last Modified in 12/16/23 | 3 | 61 | 59 | 0 | 0 | 0 | 0 | 1 |
[9] † Jeholodens Last Modified in 12/16/23 | 9 | 54 | 53 | 0 | 0 | 0 | 0 | 1 |
[10] † Priacodon Last Modified in 12/16/23 | 0 | 62 | 62 | 0 | 0 | 0 | 0 | 1 |
[11] † Triconodon Last Modified in 12/16/23 | 0 | 63 | 62 | 0 | 0 | 0 | 0 | 1 |
[12] † Trioracodon Last Modified in 12/16/23 | 0 | 62 | 62 | 0 | 0 | 0 | 0 | 1 |
[13] † Astroconodon Last Modified in 12/16/23 | 7 | 55 | 55 | 0 | 0 | 0 | 0 | 1 |
[14] † Alticonodon Last Modified in 12/16/23 | 32 | 30 | 30 | 0 | 0 | 0 | 0 | 1 |
[15] † Corviconodon Last Modified in 12/16/23 | 13 | 50 | 49 | 0 | 0 | 0 | 0 | 1 |
[16] † Aploconodon Last Modified in 12/16/23 | 26 | 37 | 36 | 0 | 0 | 0 | 0 | 1 |
[17] † Phascolotherium Last Modified in 12/16/23 | 6 | 56 | 56 | 0 | 0 | 0 | 0 | 1 |
[18] † Amphilestes Last Modified in 12/16/23 | 5 | 57 | 57 | 0 | 0 | 0 | 0 | 1 |
[19] † Amphidon Last Modified in 12/16/23 | 14 | 48 | 48 | 0 | 0 | 0 | 0 | 1 |
[20] † Hakusanodon Last Modified in 12/16/23 | 13 | 49 | 49 | 0 | 0 | 0 | 0 | 1 |
[21] † Comodon Last Modified in 12/16/23 | 31 | 31 | 31 | 0 | 0 | 0 | 0 | 1 |
[22] † Gobiconodon Last Modified in 12/16/23 | 1 | 62 | 61 | 0 | 0 | 0 | 0 | 1 |
[23] † Tinodon Last Modified in 12/16/23 | 2 | 61 | 60 | 0 | 0 | 0 | 0 | 1 |
[24] † Zhangheotheriidae Last Modified in 12/16/23 | 1 | 61 | 61 | 0 | 0 | 0 | 0 | 1 |
[25] † Spalacotheriidae Last Modified in 12/16/23 | 0 | 63 | 62 | 0 | 0 | 0 | 0 | 1 |
[26] † Amphitherium Last Modified in 12/16/23 | 3 | 59 | 59 | 0 | 0 | 0 | 0 | 1 |
[27] † Repenomamus Last Modified in 12/16/23 | 0 | 62 | 62 | 0 | 0 | 0 | 0 | 1 |
[28] † Arundelconodon Last Modified in 12/16/23 | 25 | 38 | 37 | 0 | 0 | 0 | 0 | 1 |
Project views
type | number of views | Individual items viewed (where applicable) |
Total project views | 1769 | |
Matrix views | 70 | Matrix landing page (65 views); Rougier 2007 (5 views); |
Views for media list | 70 | |
Media views | 428 | Media search (203 views); M898407 (34 views); M898405 (33 views); M898409 (31 views); M898408 (34 views); M898410 (31 views); M898406 (62 views); |
Documents list | 64 | |
Specimen list | 410 | |
Taxon list | 573 | |
Project overview | 103 | |
Bibliography | 51 |
Project downloads
type | number of downloads | Individual items downloaded (where applicable) |
Total downloads from project | 2 | |
Document downloads | 1 | Rougier 2007 (Original PBDB Matrix) (1 download); |
Matrix downloads | 1 | Rougier 2007 (1 download); |