DinosauriaSauropoda paleophysiology body mass estimation specific tissue density paleoecology Abstract Body mass and surface areas are important in several aspects for an organism living today. Therefore, mass and surface determinations for extinct dinosaurs could be important for paleo-biological aspects as well. Based on photogrammetrical measurement the body mass and body surface area of the Late Jurassic Brachiosaurus brancai Janensch, 1914 from Tendaguru (East Africa), a skeleton mounted and exhibited at the Museum of Natural History in Berlin (Germany), has been re-evaluated. We determined for a slim type of 3D reconstruction of Brachiosaurus brancai a total volume of 47.9 m 3 which represents, assuming a mean tissue density of 0.8 kg per 1,000 cm 3 , a total body mass of 38,000 kg. The volume distributions from the head to the tail were as follows: 0.2 m 3 for the head, neck 7.3 m 3 , fore limbs 2.9 m 3 , hind limbs 2.6 m 3 , thoracic-abdominal cavity 32.4 m 3 , tail 2.2 m 3 . The total body surface area was calculated to be 119.1 m 2 , specifically 1.5 m 2 for the head, 26 m 2 neck, fore limbs 18.8 m 2 , hind limbs 16.4 m 2 , 44.2 m 2 thoracic-abdominal cavity, and finally the tail 12.2 m 2 . Finally, allometric equations were used to estimate presumable organ sizes of this extinct dinosaur and to test whether their dimensions really fit into the thoracic and abdominal cavity of Brachiosaurus brancai if a slim body shape of this sauropod is assumed. museum fü r naturkunde

Both body mass and surface area are factors determining the essence of any living organism. This should also hold true for an extinct organism such as a dinosaur. The present report discusses the use of a new 3D laser scanner method to establish body masses and surface areas of an Asian elephant (Zoological Museum of Copenhagen, Denmark) and of Plateosaurus engelhardti, a prosauropod from the Upper Triassic, exhibited at the Paleontological Museum in Tübingen (Germany). This method was used to study the effect that slight changes in body shape had on body mass for P. engelhardti. It was established that body volumes varied between 0.79 m(3) (slim version) and 1.14 m(3) (robust version), resulting in a presumable body mass of 630 and 912 kg, respectively. The total body surface areas ranged between 8.8 and 10.2 m(2), of which, in both reconstructions of P. engelhardti, approximately 33% account for the thorax area alone. The main difference between the two models is in the tail and hind limb reconstruction. The tail of the slim version has a surface area of 1.98 m(2), whereas that of the robust version has a surface area of 2.73 m(2). The body volumes calculated for the slim version were as follows: head 0.006 m(3), neck 0.016 m(3), fore limbs 0.020 m(3), hind limbs 0.08 m(3), thoracic cavity 0.533 m(3), and tail 0.136 m(3). For the robust model, the following volumes were established: 0.01 m(3) head, neck 0.026 m(3), fore limbs 0.025 m(3), hind limbs 0.18 m(3), thoracic cavity 0.616 m(3), and finally, tail 0.28 m(3). Based on these body volumes, scaling equations were used to assess the size that the organs of this extinct dinosaur have.

Body mass and surface areas are important in several aspects for an organism living today. Therefore, mass and surface determinations for extinct dinosaurs could be important for paleo‐biological aspects as well. Based on photogrammetrical measurement the body mass and body surface area of the Late Jurassic Brachiosaurus brancai Janensch, 1914 from Tendaguru (East Africa), a skeleton mounted and exhibited at the Museum of Natural History in Berlin (Germany), has been re‐evaluated. We determined for a slim type of 3D reconstruction of Brachiosaurus brancai a total volume of 47.9 m3 which represents, assuming a mean tissue density of 0.8 kg per 1,000 cm3, a total body mass of 38,000 kg. The volume distributions from the head to the tail were as follows: 0.2 m3 for the head, neck 7.3 m3, fore limbs 2.9 m3, hind limbs 2.6 m3, thoracic‐abdominal cavity 32.4 m3, tail 2.2 m3. The total body surface area was calculated to be 119.1 m2, specifically 1.5 m2 for the head, 26 m2 neck, fore limbs 18.8 m2, hind limbs 16.4 m2, 44.2 m2 thoracic‐abdominal cavity, and finally the tail 12.2 m2. Finally, allometric equations were used to estimate presumable organ sizes of this extinct dinosaur and to test whether their dimensions really fit into the thoracic and abdominal cavity of Brachiosaurus brancai if a slim body shape of this sauropod is assumed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Allometric equations are often based on the body mass of an animal because body mass determines many physiological functions. This should also hold for Brachiosaurus brancai and Dicraeosaurus hansemanni, two sauropods from the Upper Jurassic of Tendaguru/Tanzania (East Africa) . Widely divergent estimates of body mass for the same specimen can be found in the literature for these two sauropods. Therefore, in order to determine the exact body mass and volume distribution in these sauropods, classical three-dimensional stereophotogrammetry as well as a newly developed laser scanner technique were applied to the mounted skeletons of Brachiosaurus brancai and Dicraeosaurus hansemanni in the Museum für Naturkunde (Berlin, Germany) . Thereafter, scaling equations were used to estimate the size of organ systems. In a second step it was tested whether the given data from photogrammetry could be brought in line with the results derived from the allometric equations. These findings are applied to possible ecological problems in the Upper Jurassic of Tendaguru/Tanzania .Key words: Dinosauria, Sauropoda, palaeophysiology, evolutionary physiology, palaeoecology, body mass estimations, metabolism, nutrition, gait and posture . ZusammenfassungDer Körpermasse eines Organismus werden oft allometrische Funktionen zugrunde gelegt, da von ihr viele physiologische Funktionen entscheidend abhängen . Dies sollte auch für ausgestorbene Organismen wie Brachiosaurus brancai und Dicraeosaurus hansemanni, zwei Sauropoden aus dem oberen Jura von Tendaguru/Tanzania in Ostafrika gelten. Da zu beiden Sauropoden nur sehr unterschiedliche Massenabschätzungen vorliegen, wurden die Körpermassen und Volumina von Brachiosaurus brancai und Dicraeosaurus hansemanni mit Hilfe der klassischen Photogrammetrie sowie einem neuentwickelten Laserscannerverfahren neu bestimmt. Basierend auf den so gemessenen Körpermassendaten wurden anschließend einige wichtige funktionell-morphologische Größen für eine paläophysiologische Rekonstruktion dieser Sauropoden mit Hilfe der Allometrie berechnet. Die gewonnenen Ergebnisse sind u . a. wichtig für die Rekonstruktion eines Ökosystems im oberen Jura von Ostafrika .

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