A New Sauropodomorph Dinosaur from the Early Jurassic of Patagonia and the Origin and Evolution of the Sauropod-type Sacrum

Pol, Diego; Garrido, Alberto C.; Cerda, Ignacio Alejandro

doi:10.1371/journal.pone.0014572

Cited by 79 publications

(160 citation statements)

References 45 publications

(81 reference statements)

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“…Ridge or lateral swelling of lateral surface of the dentary (possibly associated with a fleshy cheek in life): 0, absent, 1, present (Gauthier, 1986;Galton and Upchurch, 2004;Pol et al, 2011b).…”

mentioning

confidence: 99%

“…Dorsoventral extension of lacrimal antorbital fossa: 0, through more than half of the bone height; 1, is restricted to the ventral half of the bone (Langer, 2004;Pol et al, 2011b).…”

mentioning

confidence: 99%

“…Ventral rim of the antorbital fossa: 0, parallel to tooth row, 1, ventrally sloped in its caudal part (Langer, 2004;Pol et al, 2011b).…”

mentioning

confidence: 99%

“…Descending process of lacrimal: 0, curved, subvertically oriented (at its dorsal half), 1, straight and obliquely oriented along its entire length (Pol et al, 2011b).…”

mentioning

confidence: 99%

“…Length of the anterior (rostral) ramus of the lacrimal: 0, greater than half the length of the ventral ramus, 1, less than half the length of the ventral ramus (Yates, 2007;Pol et al, 2011b).…”

mentioning

confidence: 99%

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A new hypothesis of dinosaur relationships and early dinosaur evolution

Baron

Norman

Barrett

2017

Nature

230

306

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Further discussion of the main phylogenetic analysesTrees were produced and analysed in TNT 1.5-beta (Goloboff et al. 2008). In total 74 taxa were scored for 457 characters. Using the new technology search function, with ratchet and drift set to their defaults (10 iterations and 10 cycles respectively) and with 100 random additional sequences, our data produced 93 MPTs of length 1734. Bremer supports were also calculated using TNT 1.5-beta.The following characters were treated as ordered: 24, 35, 39, 60, 68, 71, 117, 145, 167, 169, 174, 180, 197, 199, 206, 214, 215, 222, 251, 269, 272, 286, 289, 303, 305, 307, 313, 322, 333, 334, 338, 353, 360, 376, 378, 387, 393, 442, 446 Our characters were drawn and modified from a number of previous studies and supplemented with an additional 63 novel characters. The main sources of our characters were Gauthier (1986), Sereno (1991), Langer and Benton (2006), Yates (2007), Butler et al. (2008), , Nesbitt (2011) and Pol et al. (2011).Our investigations and analyses showed that a number of characters previously thought only to appear in theropods or sauropodomorphs (or both) can also found in a several ornithischian taxa and, conversely, a number of features traditionally associated with basal ornithischian taxa are also present in basal theropods and, in some instances, sauropodomorphs. Furthermore, many other characters that are more traditionally associated with only one or two dinosauriform groups were found to have a wider and/or more complex distribution than other studies have previously proposed, e.g. a mediolaterally oriented scar on the anterior face of the distal femur -present in Dromomeron (Nesbitt et al. 2009a), is also found in some herrerasaurids (PVSJ 373). We tried, as objectively as possible, to capture all these similarities, as well as notable differences, between the basal members of each of the major dinosaurian lineages using our newly composed set of characters.Critically, a large number of character states were found to be present in ornithischians and theropods only (see below). Additionally, a number of other character states were found that are present only in sauropodomorphs and herrerasaurids. Some previously proposed dinosaur synapomorphies were also found to be absent from a few important early dinosaur taxa. In most of these cases, our finds changed the optimisations of important characters within the tree, often leading to changes in the structure of the tree itself, as well as our interpretation of the basal dinosaur interrelationships that the distributions of these character states imply.A number of novel clades were recovered by our analysis. Of these, Ornithoscelida is the most strikingly different from previous systems of grouping and classification. A full list of synapomorphies for each of the major clades that we have recovered is given later in this Supplement (Section 3.4). A discussion of a few of the other important finds of our analysis follows here.A constraint tree was also produced in TNT 1.5-beta in order to test how man...

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mentioning

confidence: 99%

“…Dorsoventral extension of lacrimal antorbital fossa: 0, through more than half of the bone height; 1, is restricted to the ventral half of the bone (Langer, 2004;Pol et al, 2011b).…”

mentioning

confidence: 99%

“…Ventral rim of the antorbital fossa: 0, parallel to tooth row, 1, ventrally sloped in its caudal part (Langer, 2004;Pol et al, 2011b).…”

mentioning

confidence: 99%

“…Descending process of lacrimal: 0, curved, subvertically oriented (at its dorsal half), 1, straight and obliquely oriented along its entire length (Pol et al, 2011b).…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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A new hypothesis of dinosaur relationships and early dinosaur evolution

Baron

Norman

Barrett

2017

Nature

230

306

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References

2012

Dinosaur Paleobiology

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The Long Bone Histology of the Sauropodomorph, Antetonitrus ingenipes

Krupandan

Chinsamy

Pol

2018

The Anatomical Record

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This analysis of the long bone microstructure of Antetonitrus ingenipes fills a crucial gap in our understanding of the growth dynamics of sauropodomorph dinosaurs. The bone histology of basal Sauropodomorpha are often characterized by zonal tissue, and contrasts with that of more derived sauropod taxa which show a shift toward the deposition of uninterrupted fibrolamellar bone (with lines of growth being either absent or only present in the outer circumferential layer). In Antetonitrus, growth patterns in the youngest individuals exhibit uninterrupted fibrolamellar bone without any growth marks. Subadult individuals, also exhibit highly vascularized fibrolamellar bone throughout the cortex, as in more derived Sauropods and Mussaurus, but growth lines occur intermittently (although not regularly) throughout the cortex as in Lessemsaurus. This indicates that Antetonitrus does not exhibit the growth dynamics previously considered characteristic of Sauropoda. Despite this, the largest (and possibly the oldest femur, NMQR 1705/163) does show an incipient external fundamental system (EFS). Our findings further suggest that growth marks are decoupled from bone size, which indicates a level of developmental plasticity in this taxon. Modulations or textural shifts in the pattern of vascular channel arrangements throughout the fibrolamellar bone in the cortex may be related to periods of resource limitations, although the lack of consistency of these modulations suggest that it is unlikely due to seasonal fluctuations. Localized bands of radial fibrolamellar bone, followed by resumption of normal growth in two samples are interpreted as evidence of a disease infliction, and subsequent recovery thereof. Anat Rec, 301:1506Rec, 301: -1518Rec, 301: , 2018 Bone microstructure (osteohistology) provides a direct record of ontogenetic growth and provides a wealth of data on various aspects of dinosaur paleobiology, such as, growth rates, ontogenetic stages, and termination of growth (e.g., Chinsamy-Turan, 2005;Cerda et al., 2013). Studies of the bone histology of sauropodomorph bones have been

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A New Sauropodomorph Dinosaur from the Early Jurassic of Patagonia and the Origin and Evolution of the Sauropod-type Sacrum

Cited by 79 publications

References 45 publications

A new hypothesis of dinosaur relationships and early dinosaur evolution

A new hypothesis of dinosaur relationships and early dinosaur evolution

References

The Long Bone Histology of the Sauropodomorph, Antetonitrus ingenipes

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