Endocone diaphragms and the 'phragmocone of Ecdyceras' (Nautiloidea)
D. H. Collins
An endocerid nautiloid, Loxendoceras trimerum n. gen., n. sp., is described, and another species, Lobendoceras emanuelense Teichert & Glenister 1954, is confirmed as an endocerid. The similarity of complex endosiphuncular structures to the internal structures of the 'phragmocones' attributed to Ecdyceras by Flower (1962) induced a reevaluation of Flower's conclusions. The internal structures of Flower's Ecdyceras 'phragmocones' differ so radically from the phragmocone structures of all known nautiloids that Flower's interpretation seems dubious. Furthermore, there seems little evidence to connect the 'phragmocones' to Ecdyceras. Interpreted as endocerid endosiphuncles, Flower's 'phragmocones' possess easily recognizable complex diaphragms, complex endosiphocones and complex endosiphotubes. From this similarity of internal structures and from the occurrence of endocerid endosiphuncles close to the locality where Flower's Ecdyceras 'phragmocones' were collected, it is evident that the 'phragmocones' are probably endocerid endosiphuncles. If so, then Flower's family Ecdyceratidae and order Ecdyceratida are not sufficiently different from other taxa of the same rank to warrant their recognition.
This record provided courtesy of AGI/GeoRef.
