Eusthenodon

Abstract: Two well-preserved articulated tristichopterids are known from the Canowindra fossil fish locality (Frasnian) in central New South Wales: Mandageria Johanson & Ahlberg, 1997 and Cabonnichthys Ahlberg & Johanson, 1997. Two other large tristichopterids are Notorhizodon Young et al., 1992 from the Aztec Siltstone fauna of Antarctica (Givetian), and the Famennian Eusthenodon Jarvik, 1952, first described from East Greenland and recently identified in eastern Australia. Relationships of the East Gondwana tristichopterids were previously assessed as Notorhizodon [Platycephalichthys [Cabonnichthys [Mandageria [Eusthenodon]]]], with no endemic Gondwanan clade, and more basal tristichopterids (Tristichopterus, Eusthenopteron, Jarvikina) being Northern Hemisphere forms. This suggested that the group may have originated in Laurussia, with advanced tristichopterids later reaching Gondwana (Middle–Late Devonian). Reconsideration of evidence from structure of the palate and scale morphology suggests an alternative phyl...

Abstract: We describe new material of the tristichopterids cf. Langlieria socqueti and cf. Eusthenodon wangsjoi and other unassignable tetrapodomorph remains from the upper Famennian locality of Strud, Belgi...

Abstract: New material from the Upper Devonian (Famennian) Catskill Formation of Pennsylvania, USA, reveals anatomical details previously lacking from the enigmatic fossil species that Newberry (1889, U.S. Geological Survey Monograph 16:1–228) named Holoptychius ? radiatus. The original material (scales and lepidotrichia) was attributed to Holoptychius (Sarcopterygii, Porolepiformes) according to the ridged ornament on the exposed portion of the scales. Scale and cranial anatomy revealed by the new material supports a reassignment of the species to Langlieria (Sarcopterygii, Tristichopteridae). The emended diagnosis of the new combination includes the grooved scale ornament that was noted, though described differently by Newberry, and a posterior oblique pitline groove of the parietal that extends to the caudal margin of the element. Along with Hyneria lindae and Eusthenodon sp. indet., there are now at least three known species of Tristichopteridae from the Catskill Formation. Temporal/spatial separation of these species, along with supporting anatomical characteristics, suggests that tristichopterids commonly filled the ecological niche of top predator in the Famennian-age nonmarine ecosystems of the Catskill Delta Complex. The presence of a Langlieria species in the Catskill Formation lends further support to a biogeographic connection between Pennsylvania, USA, and Belgium during the Famennian Stage of the Upper Devonian.

Abstract: A new species of Eusthenodon from the Upper Devonian (Famennian) Catskill Formation was collected from talus blocks at the base of a road cut along the Cogan House Exit Ramp on U.S. 15/Interstate 9...