Figure 1.
Geographic location and stratigraphic position of the Red Hill I field site (UCMP V74084) in Eureka Co., Nevada, USA.
Black patterning within Eureka County represents exposed Devonian outcrops. Stars represent where the fossil material was collected. Red Hill I section courtesy of H.-P. Schultze.
Figure 2.
Holotype specimen UCMP 118605, interpretive drawing, and complete restoration of Tinirau clackae.
(A) UCMP 118605, holotype, in dorsal, lateral and ventral view. See main text for details. Right is anterior. Scale bar equals 10 cm; (B) complete restoration; preserved elements outlined in black, inferred margins outlined in dashed black, hypothesized elements outlined in gray. See methods section for anatomical abbreviations. Note the reduced postaxial fibular processes on the fibulae (fib.p).
Figure 3.
Ethmoid skull region and palate of Tinirau clackae.
(A-i) UCMP 117884, ethmoid skull. Anterior is toward the top of the page. Scale bar equals 2 cm; (A-ii) dorsal skull reconstruction with infilled gray ethmoid region following from (A-i); (B) Left palatal fragment of UCMP 190998. Right is anterior. Scale bar equals 5 cm; (C) Skull, partial shoulder, and interpretive drawing of UCMP 190999. Uniform stipple covering distal jaw elements indicate unexposed portions of the specimen still covered by bioplastic; similarly, the dotted line posterior to the parasphenoid (Psph) notes the division between ethmoid and oticoccipital regions recovered from X-ray imaging. Anterior is toward the top of the page. Scale bar equals 5 cm. See methods section for anatomical abbreviations. Note the elongate glenoid fossa (gle) on the left scapulocoracoid (Sco).
Figure 4.
Interrelationships among Devonian and select Carboniferous tetrapodomorphs including new data from Tinirau clackae.
Analysis includes 46 taxa and 204 characters. Tree length = 454, consistency index = 0.5572, retention index = 0.8481; consistency index excluding the four autapomorphic (uninformative) characters = 0.5532, retention index = 0.8481. Numbers corresponding to respective nodes represent: Bremer decay value/Bayesian posterior probability. Ghost ranges are calibrated after the early Middle Devonian (Eifelian) Zachełmie tracks ([15] and “scenario 1” from Friedman and Brazeau (2011). Tetrapodomorphs include all taxa that are not total-group lungfishes. Rhizodonts are in green, canowindrids are in yellow, megalichthyiforms are in blue, tristichopterids are in purple, Devonian elpistostegalians are in red, and Carboniferous elpistostegalians are in orange. The character list and data matrix are available as supplementary information.
Figure 5.
Glenoid fossae and pelvic limbs of select stem-tetrapods.
Glenoids are illustrated in posterior view and highlighted in blue, fibulae are highlighted in green. The glenoid of Tiktaalik is depicted from two different perspectives, posterior view (above) and posteroventral view (below). The largest Tiktaalik specimens are more oblate, which may be autapomorphic relative to the condition in more crownward Devonian and Carboniferous taxa. The glenoid of Panderichthys was based on the shape of its caput humerus. See text for additional details. The in-plane glenoid measurement (height at maximum extent divided by maximum length) diagnoses an elongate glenoid fossa: Medoevia = 0.60; Eusthenopteron = 0.60; Tinirau = 0.42; Panderichthys = 0.48; Tiktaalik = 0.44; Acanthostega = 0.45.
Figure 6.
The nested phylogenetic position of Eusthenopteron within tristichopterids (Spodichthys+closest relatives) relative to Tinirau, Platycephalichthys, Panderichthys, and more crownward taxa.
Character states supporting this topology: (1) a parasymphyseal plate not sutured to the anterior coronoid; (2) posterior coronoids longer than more anterior coronoids; (3) 33–40% of the dermatocranium anterior to the orbits; (4) a posteriorly displaced postspiracular; (5) posterior coronoids one third longer than the anterior coronoids; (6) two ectopterygoid fang pairs; and (7) a diphycercal caudal fin.