Theoretical 3D models were digitally reconstructed from a phragmocone section of Baculites compressus in order to investigate the hydrostatic properties of the orthoconic morphotype. These virtual models all had the capacity for neutral buoyancy (or nearly so) and were highly stable with vertical syn vivo orientations. Body chamber lengths exceeding approximately 40% of the shell length cause buoyancy to become negative with the given modeled proportions. The distribution of cameral liquid within the phragmocone does not change orientation and only slightly influences hydrostatic stability. The mass of cameral liquid required to completely reduce stability, permitting a non-vertical static orientation, would cause the living cephalopod to become negatively buoyant. A concave dorsum does not significantly change the mass distribution and results in a 5° dorsal rotation of the aperture from vertical. The restoring moments acting to return neutrally buoyant objects to their equilibrium position were investigated using 3D-printed models of Nautilus pompilius and Baculites compressus with theoretically equal masses and hydrostatic stabilities to their virtual counterparts. The N. pompilius behaved as an underdamped harmonic oscillator during restoration due to its low hydrostatic stability and drag relative to the B. compressus model. In contrast, the B. compressus model more quickly returns to its equilibrium position without oscillating (overdamped system). The thrust required to overcome such a large restoring moment was explored using several extant cephalopod analogues. Significant angles of displacement were only achieved with coleoid-like thrusts, which were unrealistically high despite the probable similarities in their locomotor design. These maximum bursts of thrust may have been too energetically expensive and would preclude an unusual form of locomotion in a non-vertical orientation. These results suggest baculitids and other orthocones with similar hydrostatic stabilities probably lived a nektic to quasiplanktic mode of life with a primarily vertical orientation and mobility.

The biomechanics of uncoiled heteromorph ammonoids with body chambers that terminate in U-shaped hooks (ancylocones) were investigated with virtual and physical models of Audouliceras renauxianum. Virtual models were used to compute the hydrostatic properties of this morphotype. Audouliceras has the capacity for neutral buoyancy and this suggests that other taxa with similar proportions had this ability as well. Hydrostatic stability gradually increases during ontogeny, coincident with the larger degree of uncoiling. The juvenile planispiral stage has a similar stability and apertural orientation to the extant Nautilus. The adult stage, however, undergoes an increase in stability by a factor of over 3, while assuming an upward-facing posture. Counterintuitively, the stage during the formation of the shaft (before the growth of the U-shaped hook) is oriented horizontally. This intermediate stage would have had poor horizontal mobility due to the positioning of the hyponome below the centre of mass. The juvenile planispiral stage and mature stage, however, would have been well suited to horizontal backward movement with minimal rocking. Ancylocones are generally thought of as quasiplanktic vertical migrants. Thus, their relative horizontal swimming ability has been largely disregarded. Experiments on 3D printed, neutrally buoyant physical models reveal that hydrodynamic drag is indeed larger compared to Nautilus. However, Audouliceras could reach similar maximum horizontal velocities depending on the available thrust. Sepia-like thrusts yield velocities similar to equivalently sized Nautilus (c. 15 cm/s), while Nautilus-like thrusts yield velocities not much lower (c. 11 cm/s). Due to the hydrostatic properties of the ancylocone, the adult model undergoes less rocking (±4.5°) during movement than Nautilus (±10°). The minimal hydrodynamic consequences for ancylocones suggest that stability, orientation and directional efficiency are key selective pressures for some heteromorph shells, which may have primarily served as hydrostatic devices.

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Karst features in the Silurian dolomites of Taylorsville MetroPark (Dayton Metropolitan Area, Ohio, United States) were explored from 2017 to 2018 to identify sites of paleontological interest. Initial landscape surveys recovered 124 skeletal elements (from 12 sites) that were attributed to 17 vertebrate species—including evidence of such extirpated animals as bobcats (Lynx rufus) and rattlesnakes (Crotalus sp.). Of the 12 sites, 9 sites contained remains from the historical era and 3 sites contained much older remains (n = 17) that were radiocarbon dated to approximately 1,400 years before present (YBP). Human remains at one site, butchered bones at another, and artifacts from a third suggest a long period of pre-colonial human use of the area. The presence of rare taxa expands pre-historical species lists and confirms the coexistence of many previously undocumented taxa from the area during the late, pre-colonial, Holocene Epoch.