The color pattern on a Cretaceous nautiloid from South Dakota

Abstract

Preservation of relict color patterns on fossil nautiloid cephalopods is a relatively rare phenomenon. Reports of this phenomenon as summarized by Kobluck and Mapes (1989, table 2) for the Paleozoic indicate that perhaps as many as 32 genera with coiled, orthoconic, and cyrtoconic conchs have been described with relict color patterns. However, reports of Mesozoic occurrences are limited to only Ophionautilus? in the Jurassic (Shimanski, 1962) and Eutrephoceras in the Cretaceous (Shimanski, 1962; Landman, 1982). Cenozoic reports are limited to Aturia in the Tertiary (Foerste, 1930; Shimanski, 1962; Teichert, 1964) and modern Nautilus (see Saunders and Landman, 1987, for an extensive treatment). The reports on both Mesozoic occurrences are limited to description of external conch morphology, detailed appearance of the color patterns, and the relationship of the remnant color pattern to the conch morphology. Indeed, the specimen discussed herein was originally illustrated by Landman (1982, fig. 8), with a caption indicating the presence of possible color banding. Analysis of this Cretaceous specimen allows comparison to Nautilus and provides a suggestion as to the evolution of certain mature color patterns in coiled cephalopods from the late Mesozoic to Recent.

Colour pattern polymorphism in Silurian nautiloid Phragmoceras Broderip, 1839

“…Intensive colouring of the convex dorsal and dorsolateral sides in Phragmoceras dubium resembles colouring of convex ventral and ventrolateral regions of the shell in extant Nautilus and Allonautilus. Furthermore, the shell colouration in Phragmoceras dubium resembles colouration observed in Cretaceous nautilid Eutrephoceras Hyatt, 1894 illustrated by Mapes & Evans (1995) in which colour bands are subparallel with growth lines along the entire circumference of the shell. It represents a striking convergence in colour pattern development, although the living position of Phragmoceras compared to the above mentioned nautilids had to be quite different (see Manda 2008).…”

First Evidence of Color Patterns on Conchs of the Lower Moscovian (Middle Pennsylvanian) Coiled Nautiloids From the Donets Basin, Ukraine

“…At present, color patterns is known on shells of the following post-Carboniferous coiled nau-tiloids: Stenopoceras from the Cisuralian of Texas, USA (Kemp 1957), ?Ophinautilus from the Late Jurassic of Russia (Shimansky 1961(Shimansky , 1962, Eutrephoceras from the Early Cretaceous of Russia (Shimansky 1961(Shimansky , 1962 and the Late Cretaceous of South Dakota, USA (Mapes & Evans 1995), Aturia from Paleogene and Neogene of France and Italy (Foerste 1930;Teichert 1964). Remarkably, the conch coloration of lower Paleozoic cephalopods is much better known (see Foerste 1930;Balashov 1964;Turek 2009;Turek & Manda 2011, 2020Manda & Turek 2009.…”

Developmental Integration Related to Buoyancy Control in Nautiloids: Evidence From Unusual Septal Approximation and Ontogenetic Allometries in a Jurassic Species

“…Some (2–4) can be easily observed, even in poorly preserved specimens, whereas others (1, 5–8) require well preserved material. For example, Mapes and Evans (1995) have shown that cessation of secretion of the colour bands on the venter occurs at about one‐fifth of the whorl adapical of the fully mature aperture in the Cretaceous species Eutrephoceras dekayi . Secretion of a black band along the interior margin of the aperture had never been reported in fossil species, which could be explained because of its proteinaceous nature.…”