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Species / Tessarolax Grahami

Tessarolax Grahami

Stromboidea


Original Diagnosis of Tessarolax grahami by Saul & Squires, 2015:

  • Mature last whorl bicarinate, anterior carina forming high crest of three short spines (middle spine largest) on elevated thin dorsal septum; callus covering shell; fictavarix narrow and somewhat knob-shaped, extending ventrally to form stabilizer.

Original Description of Tessarolax grahami by Saul & Squires, 2015:

  • " Shell fragile and thin, up to 87 mm high and 43 mm wide (essentially complete). Pleural angle 30 to 40 degrees. Protoconch unknown. Teleoconch approximately six whorls. Suture callused over. Immature shell: Turriculate, consisting of approximately five whorls, early spire whorls unicarinate and finely ribbed. Mature shell: Consisting of last whorl, bicarinate, carinae subparallel and without nodes; posterior carina weakest and thin; anterior carina near center or dorsum with several (commonly three) short spines (middle one longest) that form high crest on thin, projecting septum. Aperture moderately narrow. Outer lip expanded into four canaliculate digitations. Apical digitation straight, extending along spire but diverting from tip of shell. Posterior and anterior outer lip digitations long and curved and extending from their respective carinae. Anterior outer lip digitation straight and bearing callus knob that can be elongate. Rostral digitation slightly curved. Callus covering shell, obscuring ornamentation except for carinae on last whorl. Callus on venter forms flattened surface. Fictavarix narrow and projecting, not merging with ventral callus; somewhat knob-shaped, extending ventrally to support ablabral side of shell aperture."

Locus typicus: South bank of French Creek near Coombs, Nanaimo District, Nanaimo, Vancouver Island, British Columbia Province, Canada

Stratum typicum: Cedar District Formation, upper middle Campanian, upper Cretaceous

Geographic Range: Vancouver Island, British Columbia Province, Canada to southern California., USA.

Etymology: The species is named for Raymond Graham, who found many of the specimens of this new species and provided valuable biostratigraphic information about them.

Tessarolax grahami Saul & Squires, 2015; Holotype; Cedar District Formation, upper middle Campanian, upper Cretaceous; South bank of French Creek near Coombs, Nanaimo District, Nanaimo, Vancouver Island, British Columbia Province, Canada; Coll. RBCM.EH2011.007.0008; Copyright Natural History Museum of Los Angeles County.

Tessarolax grahami Saul & Squires, 2015; Paratype; Cedar District Formation, upper middle Campanian, upper Cretaceous; Ship Point, eastern side of Ship Peninsula, southeast of Fanny Bay, Vancouver Island, British Columbia Province, Canada; Coll. RBCM.EH2011.007.0010; Copyright Natural History Museum of Los Angeles County.

Tessarolax grahami Saul & Squires, 2015; Paratype; Cedar District Formation, upper middle Campanian, upper Cretaceous; Ship Point, eastern side of Ship Peninsula, southeast of Fanny Bay, Vancouver Island, British Columbia Province, Canada; Coll. RBCM.EH2011.007.0009; Copyright Natural History Museum of Los Angeles County.

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