English: A diagram showing the comparative size of four different large titanosaur specimens, BIBE 45854, USNM 10486, USNM 15560, and TMM 43621-1 compared to a human. USNM 10486 is the type specimen of Alamosaurus, only known from a single scapula. The other three have been assigned to the genus Alamosaurus by various authors. However, a 2025 study has suggested that much of the material referred to Alamosaurus might represent multiple genera, and the study assigned USNM 15560 to a new genus, Utetitan. Due to the incomplete nature of the material, the silhouettes shown here are approximate.

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• The genus Alamosaurus was founded in 1922 based on a single scapula, the type specimen USNM 10486. An ischium, USNM 10487, was assigned as a paratype. Over the years, various other specimens have been referred to the genus. One of these specimens is a partial specimen described in 1946, USNM 15560, and represented by a fairly complete tail, pectoral girdle, forelimb, and ischium.^[1] In 2011 and 2016, larger fragmentary titanosaur remains were referred to Alamosaurus, including a large articulated series of neck bones, BIBE 45854. These remains suggest sizes comparable to Argentinosaurus and Puertasaurus.^[2][3]

However, it has been suggested that the genus is actually made up of multiple species or genera. Based on anatomical and stratigraphic differences, Paul (2025) assigned USNM 15560 to a new genus, Utetitan. Paul also argued that due to a lack of anatomical overlap, the specimen BIBE 45854, the large series of neck bones, is indeterminate.^[1]

• Note: There is some uncertainty in the silhouettes shown here, as none of the specimens are completely known. Cross-scaling these incomplete specimens is required to get an idea of their size and body proportions. Other cross-scaling interpretations are possible.^[4] Specifically, the large neck bones can suggest a very large titanosaur, or something closer in size to USNM 15560, just with a proportionally larger neck.^[5]

• Alamosaurus silhouette modified from skeletal reconstructions by Scott Hartman, used with permission.^[4] The size of TMM 43621-1 is based on Lehman & Coulson 2002^[6] and the sizes of USNM 15560 and BIBE 45854 are from a diagram by Scott Hartman.^[4]

• The humans are scaled to 170 cm (5 ft 7 in) and 160 cm (5 ft 3 in) respectively.