| Amygdalodon | |
|---|---|
 | |
| Holotype specimen (A-H). And lectotype specimen (I-O). | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Genus: | †Amygdalodon |
| Species: | †A. patagonicus |
| Binomial name | |
| †Amygdalodon patagonicus Cabrera, 1947 | |
Amygdalodon (/əmɪɡˈdælədɒn/; "almond tooth" for its almond shaped teeth) was agenus of basalsauropod from the Middle Jurassic of Argentina. The type species isAmygdalodon patagonicus.[1] Fossils ofAmygdalodon have been found in theToarcianCerro Carnerero Formation of theJurassic (about 180-172 million years ago). Very little is known about it, but it is one of the few Jurassic dinosaurs from South America found thus far.
The holotype (MLP 46-VIII-21-1) consists of some vertebrae, ribs, four complete and three partial teeth, and a partial pelvis and shoulder-blade, of which was discovered in 1936. Thetype species,Amygdalodon patagonicus, was described by Cabrera inArgentina in 1947.[1] Until 1936 sauropod fossils from Argentina were completely unknown then, prompted by Piatnitzky's brief mention of "bones of a saurian of no less than 5-7m long", Dr. Tomás Suero took a trip toChubut to check out deposits overlying the Liassic of the Pampa de Agnia and discovered the remains of a Jurassic sauropod dinosaur around twice the size of Piatnitzky's estimation (in 1936).[2][full citation needed]
Amygdalodon is estimated to have been 12 metres (39 ft) long and 4 metres (13 ft) tall. Thisquadrupedal dinosaur had an estimated weight of over 5 tonnes (4.9 long tons; 5.5 short tons).[3]
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Rauhut (2003) placedAmygdalodon as Eusauropodaincertae sedis based on examination of the type material.[4] Later, a cladistic analysis conducted by Carballido et al. (2010) recovered the genus as a non-eusauropod sauropod.[5] Holwerda and Pol (2018) concurred, recoveringAmygdalodon as sister toIsanosaurus.[6] A basal sauropod classification forAmygdalodon was supported by Pol and colleagues in 2022, with it showing the first signs of dental modification for bulk feeding that is retained in later sauropods, but it does not have the vertebral features found in more derived sauropods. They found it in a polytomy with the Asian taxonGongxianosaurus, and possibly related to South AmericanVolkheimeria, though the latter had a very labile position.[7]
