The use of micro-computed tomography as a minimally invasive tool for anatomical study of bivalves (Mollusca: Bivalvia) Author Machado, Fabrizio Marcondes Author Passos, Flávio Dias Author Giribet, Gonzalo text Zoological Journal of the Linnean Society 2019 186 46 75 journal article 0024-4082 41CC8EA-67BE-4627-B941-C9E66E35972E CUSPIDARIA GLACIALIS ( SARS G. O., 1878) ( FIGS 16 , 17 ) Description Shell: Elongated, robust, inaequilateral, equivalve and slightly inflated; with a prominent and long rostrum in the posterior; smooth, valves covered by a dehiscent, thick and light brown periostracum; with a lithodesma. Mantle: Mantle margin with one anteriorly large pedal gape, extending from the anterior adductor until almost the beginning of the inhalant siphon; posteroventral mantle margin fusion formed by inner and middle folds ( Type B of Yonge, 1982 ); absence of a fourth pallial aperture. Siphons: The detailed description of this structure was not possible due to the state of contraction of the specimen analysed. Septum: Presence of a well-developed horizontal muscular septum (‘septibranch condition’) dividing the mantle cavity into infra- and supraseptal chambers; septum long and wide, perforated ventrally by five pairs of isolated septal pores. Figure 15. 3D volume rendering based on the micro-CT dataset of Cetoconcha aff. smithii , displaying internal organs. Dissection sequence in original tomographic colour, lateral view (A–A2); false-colour volume rendering, lateral view (B) and virtual dissections in sagittal (C), transverse (D, E) and frontal (F) sections. Scale bars: A–C, F = 2 mm; D, E = 1 mm. Labial palps: Poorly developed, non-lamellate, slightly asymmetrical, with the anterior palps larger than the posteriors; anterior labial palps attached to ventroanterior mantle margin, close to anterior adductor muscle. Musculature: Posterior and anterior adductor muscles present, isomyarian; with well-developed pedal and septal retractor muscles, both bifurcating before attaching to the shell; lateral septal muscle also present, more concentrated posteriorly; taenioid muscle absent. Figure 16. Selected virtual 2D sections through the micro-CT dataset of a PTA-stained specimen of Cuspidaria glacialis . Transverse (A–C), sagittal (D, E) and frontal (F, G) sections. Scale bars: A–C, F, G = 2 mm; D, E = 3 mm. Foot: Large, with a long pedal groove; byssal thread absent. Digestive system : Funnel-shaped mouth opens into thick and muscular oesophagus that enters into anterodorsal portion of stomach; stomach large, rounded, with a dorsal short projection, internal grooves not visible; stomach connected to the short and small crystalline style sac located on the median portion of the stomach floor; crystalline style present; large preys were observed inside of stomach (gastropod and ostracod: Figs 15B, F , 16D, E ); stomach surrounded dorsally and anteriorly by the gonads and digestive gland. Reproductive system : Dioecious, only ovary is visible in this specimen; ovary closely associated to the digestive gland, covering the roof of the stomach.