Notocolossus

Notocolossus , one of the largest land animal that lived in the Earth Knowledge of titanosaurian pedal structure is critical to  under...

Some sauropods from North America - Part 1



Part 1. Comments on the paper of Tschopp et al.


Reference:
Tschopp, E., Mateus, O., Benson, R. A. 2015. A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda focused on different taxa and their diagnoses.  PeerJ 3:e857

This paper is a great contribution for understanding Diplodocid sauropods. Here I give you some comments and invite to read this paper.

Diplodocidae sauropods includes some of the most popular dinosaurs with elongated necks and tails.
The clade is historically important, having provided the first published reconstruction of an entire sauropod skeleton (‘Brontosaurus’ excelsus; Marsh, 1883), the first complete sauropod skull to be described (Diplodocus; Marsh, 1884), and the first mounted sauropod specimen (Apatosaurus AMNH 460; Matthew, 1905). 

A recent paper (Tschopp et al., 2015) is focused on different taxa and their diagnoses. The authors outlines that although new taxa continue to be discovered, the vast majority of diplodocid species were described in the late 1800s and early 1900s. The high rate of early descriptions, particularly during the so-called ‘Bone Wars’ of the late 1800s, resulted also in a large number of species that are now considered invalid, questionable, or synonymous.

This work is detailed and therefore helps to clarify the valid species. Many fossil bones found long time ago and do not have precise references (taphonomic maps). Likewise, some species were based on bones that today do not have diagnostic characters. 



Figure 1Apatosaurus louisae (CM 3018), a diplodocid from the Late Jurassic at Carnegie Museum of Natural History, Pittsburgh, United States of America.  This species was 21–22.8 m long and had a mass of 16.4–22.4 t (16.1–22.0 long tons; 18.1–24.7 short tons). However, a recent paper (Bates et al. 2015) estimates for this specimen at 21.8–38.2 t (21.5–37.6 long tons; 24.0–42.1 short tons), similar in mass to the South American titanosaur Dreadnoughtus (photograph of B. Gonzalez Riga).



Figure 2. Diplodocus carnegeii close to Apatosaurus louisae at Carnegie Museum of Natural History. (photograph of B. Gonzalez Riga).






Figure 3. Barosaurus lentus at American Museum of Natural History, New York. (photograph of B. Gonzalez Riga).


Selected information of Tschopp et al. 2015:

Apatosaurus Marsh, 1877a.
Type species: Apatosaurus ajax Marsh, 1877a.
Referred species: Apatosaurus louisae Holland, 1915a.
Invalid proposed species: Apatosaurus grandis Marsh, 1877a (= Camarasaurus
grandis), A. laticollis Marsh, 1879 (nomen dubium; = A. louisae), A. minimus Mook,
1917 (non-diplodocoid neosauropod), A. alenquerensis Lapparent & Zbyszewski, 1957
(= Lourinhasaurus alenquerensis), A. yahnahpin Filla & Redman, 1994 (= Brontosaurus
yahnahpin).

Barosaurus (Marsh, 1890).
Type and only species: Barosaurus lentus (Marsh, 1890).
Invalid proposed species: Barosaurus affinis (Marsh, 1899) (nomen dubium),
Barosaurus gracilis (Russell, B´eland & McIntosh, 1980) (nomen nudum).

Brontosaurus Marsh, 1879.
Syn.: Elosaurus Peterson & Gilmore, 1902, Eobrontosaurus Bakker, 1998.
Type species: Brontosaurus excelsus Marsh, 1879.
Referred species: Brontosaurus parvus (Peterson & Gilmore, 1902), Brontosaurus
yahnahpin (Filla & Redman, 1994).
Invalid proposed species: Brontosaurus amplus Marsh, 1881 (=Brontosaurus excelsus).

Diplodocus Marsh, 1878.
Syn. Seismosaurus Gillette, 1991
Type species: Diplodocus carnegii Hatcher, 1901 (suppressing the D. longus Marsh, 1878,
see above).
Referred species: Diplodocus hallorum (Gillette, 1991).
Invalid proposed species: Diplodocus longus Marsh, 1878 (nomen dubium, previous
type species, case to ICZN in preparation to propose D. carnegii as substitute), D.
lacustris Marsh, 1884 (nomen dubium), D. hayi Holland, 1924 (=Galeamopus hayi).

Supersaurus Jensen, 1985.
Syn. Dystylosaurus Jensen, 1985; Ultrasauros Olshevsky, 1991; Dinheirosaurus Bonaparte
& amp;Mateus, 1999.
Type species: Supersaurus vivianae Jensen, 1985.
Referred species: Supersaurus lourinhanensis (Bonaparte&Mateus, 1999).