Open Paleo

Dicraeosauridae

Janensch, 1929 Type genus Dicraeosaurus

Its genera lived 184.2–121.4 million years ago Early Jurassic–Early Cretaceous

Dicraeosauridae is a family of flagellicaudatan sauropods that are the sister group to the whip-tailed diplodocids. The family includes genera such as Amargasaurus, Suuwassea, and Brachytrachelopan, and its members are best known from Africa, South America, and North America, spanning the Early or Middle Jurassic through the Early Cretaceous; several Asian taxa, including Lingwulong and Tharosaurus, have been proposed as dicraeosaurids, though this remains contested. The group stands apart from other advanced sauropods, which trend toward gigantism, in being relatively small at roughly 10 to 13 meters long and in bearing distinctively short necks built from comparatively few vertebrae. Their most striking feature is a series of extremely tall neural spines running along the neck and back, reaching bizarre proportions in forms such as Amargasaurus and Bajadasaurus. As obligate herbivores with short necks, they are thought to have browsed close to the ground or at mid height. Amargasaurus was the latest-surviving member, persisting into the Early Cretaceous.

Diagnosis

  1. Tall, dorsoventrally elongate neural spines on the cervical and dorsal vertebrae, bifurcated along much of the column
  2. Relatively short neck with comparatively few, foreshortened cervical vertebrae
  3. Postparietal fenestra present, with an expanded crista prootica on the braincase
  4. Reduced or absent pneumaticity of the presacral vertebral centra

Genera placed directly in Dicraeosauridae

  • Amargasaurus Salgado & Bonaparte, 1991 Barremian (125.8–121.4 Ma)Argentina
  • Amargatitanis Apesteguía, 2007 Barremian (125.8–121.4 Ma)Argentina
  • Athenar Whitlock et al., 2025 Kimmeridgian (154.8–149.2 Ma)United States
  • Bajadasaurus Gallina et al., 2019 Valanginian (137.1–132.6 Ma)Argentina
  • Brachytrachelopan Rauhut et al., 2005 Kimmeridgian–Tithonian (154.8–143.1 Ma)Argentina
  • Dicraeosaurus Janensch, 1914 Kimmeridgian–Tithonian (154.8–143.1 Ma)Tanzania
  • Dyslocosaurus McIntosh et al., 1992 Kimmeridgian–Tithonian (154.8–143.1 Ma)United Statesunder dispute
  • Lingwulong Xu et al., 2018 Toarcian–Bajocian (184.2–168.2 Ma)China
  • Pilmatueia Coria et al., 2019 Valanginian (137.1–132.6 Ma)Argentina
  • Smitanosaurus Whitlock & Wilson Mantilla, 2020 Kimmeridgian–Tithonian (154.8–143.1 Ma)United States
  • Suuwassea Harris & Dodson, 2004 Kimmeridgian–Tithonian (154.8–143.1 Ma)United States

References

  1. Janensch, W. (1929). Material und Formengehalt der Sauropoden in der Ausbeute der Tendaguru-Expedition [Material and taxonomic content of the sauropods in the yield of the Tendaguru Expedition]. Palaeontographica, Supplement 7 1. Reihe, Teil 2: 1-34.

    Named the subfamily Dicraeosaurinae for Dicraeosaurus, from which the family name takes its authorship by coordination.

    janensch1929b
  2. Huene, F. V. (1927). Sichtung der Grundlagen der jetzigen Kenntnis der Sauropoden [Sorting through the basis of the current knowledge of sauropods]. Eclogae Geologicae Helvetiae 20: 444-470.

    Recognized a separate family for Dicraeosaurus without naming it.

    huene1927c
  3. Sereno, P. C. (1998). A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 210: 41-83. doi:10.1127/njgpa/210/1998/41

    Provided the stem-based phylogenetic definition of Dicraeosauridae.

    sereno1998a