Seismosaurus

Seismosaurus Temporal range: Late Jurassic, ==Usage== {{Geological range|first appearance (required)|last appearance|text to display|earliest=earliest putative fossil|latest=latest putative fossil|ref=References|prefix=anything to display before the range|PS=anything to display after the range}} Note The first parameter (bold above) may not be omitted; in particular it is an error to specify only |earliest= and/or |latest=. Italic parameters are optional, bold required. Example Temporal range: Carboniferous–early Cretaceous PreЄ Є O S D C P T J K Pg N Scientific classification Kingdom: Animalia Genus: Rangea Species: Rangea examplus Illustrates the fossil range of a taxon, the geological range of a stratigraphic unit, or other ranges on a geological timescale. Intended for use in {{taxobox}}es, {{Infobox rockunit}}s, and other infoboxes. For pre-Phanerozoic ages, see {{Long fossil range}}. You can give a numeric range, or specify the periods involved. The range will be quoted in text before the timeline, unless you specify a third parameter—leaving it blank will result in no text being provided. To illustrate the range when it spans before the Ediacaran (i.e. deep into the precambrian), you should use Template:Long fossil range, which works in exactly the same way as documented here. You can also specify "earliest" and "latest" to add a "ghost" bar beyond the accepted fossil range. You can use these parameters for whatever you like; they may be useful in the case of living fossils such as the coelacanth, where you may wish to specify latest=0 to make the bar faintly extend to the present; they may also be useful where "earliest" fossils are not universally accepted—for instance, the octocorals only have a good fossil record from the Tertiary, but there are claims of Cambrian representatives. In this case, you may wish to specify earliest=middle Cambrian. Examples {{Geological range|Permian}} Permian PreЄ Є O S D C P T J K Pg N {{Geological range|Permian|Jurassic}} Permian–Jurassic PreЄ Є O S D C P T J K Pg N {{Geological range|Permian|Jurassic|earliest=Devonian|latest=Cretaceous}} Permian–Jurassic PreЄ Є O S D C P T J K Pg N {{Geological range|68|65|earliest=Permian|latest=0|PS= (see article for discussion)}} 68–65Ma (see article for discussion) PreЄ Є O S D C P T J K Pg N ↓ {{Geological range|68|65.5|late Cretaceous}} late Cretaceous PreЄ Є O S D C P T J K Pg N ↓ {{Geological range|68|65|}} PreЄ Є O S D C P T J K Pg N ↓ If you receive an error when specifying a period name, check you've spelt it right; if so, it probably isn't yet incorporated into the templates {{next period}} and {{period start}}. This is really easy to do, so feel free to add the period yourself to make future editors' lives easier! See also For organisms whose fossil range extends significantly before the Ediacaran, use Template:Long fossil range. Template:Geological range/linked
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	Dinosauria
Order:	Saurischia
Suborder:	†Sauropodomorpha
Infraorder:	†Sauropoda
Family:	†Diplodocidae
Genus:	Seismosaurus Marsh, 1878

Seismosaurus (meaning "Earth-shaking lizard") is a deprecated genus of sauropod dinosaurs. While originally thought to be a distinct genus of dinosaur, studies have since shown that it is actually a large species of the well-known genus Diplodocus, known either as D. hallorum or D. longus. Seismosaurus was named for a partial cock skeleton discovered in New Mexico in 1979 consisting of vertebrae, pelvis, and ribs. The supposed associated gastroliths appeared to be stream-deposited cobbles of a channel-lag deposit. The species was formally recognised in 1991.^[1]

Size

When first described in 1991, Gillete calculated that Seismosaurus may have been up to 54 m (177.05 ft) long, making it the longest known dinosaur (excluding those known from especially poor remains, such as Amphicoelias). Some weight estimates ranged as high as 113 (rather only 50) tonnes (125 US short tons). Since the initial description of Seismosaurus, the initial reports of gigantic size have turned out to be greatly exaggerated. The most recent studies show that Seismosaurus was in fact shorter than its relative Supersaurus at about 32-35 m (105-115 ft) long, and may have weighed about 22 to 27 tonnes (25 to 30 US short tons). This review was based on recent finding that show that the giant tail vertebrae were actually placed further forward on the tail than David Gillete originally calculated. The study shows that the complete Diplodocus skeleton at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania on which estimates of Seismosaurus were based had its 13th tail vertebra come from another dinosaur, throwing size estimates for Seismosaurus off by up to 30%.

Classification

A presentation^[2] at the annual conference of the Geological Society of America in 2004 has made a case for Seismosaurus to be reassigned as a species of Diplodocus, namely D. hallorum. The authors argue that many of the distinctive features of Seismosaurus are either pathological or as a result of misplacement of the vertebrae or cock. This suggestion was further developed by the authors in 2006, in an article where they not only synonymized the two genera and officially named Diplodocus hallorum, but also speculated that it was the same as D. longus.^[3] They eliminated one of the most distinct features of its skeleton, namely a hook-like process at the end of the ischium, by showing it to have been a vertebral neural arch fragment adhering to the ischium. Without this, the bone has a very normal outline.

References

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