taxonID	type	description	language	source
039A87863A3EB92CFC12FD6B6C3BF99C.taxon	description	(FIGS 2, 3) Description Shell: Subquadrate to subovate, robust, very compressed, strongly inaequivalve with left valve inflated and right valve flat or slightly concave; lithodesma absent. Mantle: Mantle margin fused forming a short anterior pedal aperture and posteriorly with two short and very similar siphons; fourth pallial aperture absent. Siphons: Inhalant and exhalant siphons similar in size and outline, simple tube-shaped, fused almost until the tip but not covered with periostracum; apertures of the inhalant and exhalant siphons fringed with a ring of, respectively, ~ 18 and ~ 16 short tentacles. Ctenidia: Eulamellibranch and plicate; complete with a large inner demibranch and a much reduced outer demibranch consisting only of reflected descending lamellae; presence of a marginal food groove on the inner demibranch. Labial palps: Large, wide, lamellate with sorting ridges, complete and symmetrical (typically bivalve plan). M u s c u l a t u r e: A d d u c t o r m u s cl e s p r e s e n t, w e l l developed, posterior slightly larger than anterior; presence of poorly developed posterior and anterior pedal retractor muscles.	en	Machado, Fabrizio Marcondes, Passos, Flávio Dias, Giribet, Gonzalo (2019): The use of micro-computed tomography as a minimally invasive tool for anatomical study of bivalves (Mollusca: Bivalvia). Zoological Journal of the Linnean Society 186: 46-75
039A87863A3FB92FFC33F96F6A8FF897.taxon	description	(FIGS 4, 5) Description Shell: Subovate-elongated, thin, delicate, translucid, moderately inflated in the anterior, posterior laterally compressed; external sculpture formed by thin radial ridges with sand grains attached along the entire extension of the valves; with a large lithodesma. Mantle: This specimen had an important part of the mantle lost during the removal of the shell, turning the analysis incomplete; presence of a fourth pallial aperture closer to the inhalant aperture. Siphons: Inhalant and exhalant siphons similar in size and outline, short, simple, tube-shaped and separated; papillate tentacles covering the inhalant siphon; apertures of the inhalant and exhalant fringed with a ring of, respectively, ~ 32 and ~ 45 short tentacles. Ctenidia: Eulamellibranch and plicate; complete with a large inner demibranch larger than the outer one; free edge of inner demibranch with a deep marginal food groove. Labial palps: Large, wide, lamellate with sorting ridges, symmetrical and coiled. Musculature: Adductormusclespresent, heteromyarian, with the posterior adductor well developed and the anterior reduced; presence of well-developed posterior and a reduced anterior pedal retractor muscle. Foot: Elongated with a long pedal groove; presence of byssal thread. BIVALVES AND MICRO-COMPUTED TOMOGRAPHY 53 Digestive system: The tube-shaped mouth opens into a long oesophagus that enters into the anterior portion of the stomach; elongated in shape, the stomach is connected to the also elongated crystalline style sac; style sac conjoined with an anterior coiled midgut; pericardium / heart surround the rectum / hindgut; kidney not visible. Reproductive system: Hermaphroditic; ovary located in the dorsal portion of the visceral mass, closely associated to the digestive gland; testis small and poor visible, located in the anterior portion of visceral mass.	en	Machado, Fabrizio Marcondes, Passos, Flávio Dias, Giribet, Gonzalo (2019): The use of micro-computed tomography as a minimally invasive tool for anatomical study of bivalves (Mollusca: Bivalvia). Zoological Journal of the Linnean Society 186: 46-75
039A87863A3DB921FCD5F9616AA1F90B.taxon	description	(FIGS 6, 7) Description Shell: Subquadrate, inflated, equivalveandinaequilateral; extremely fragile, pearl lustre; outer sculpture well marked with two long radial ridges from the umbo until the posterior ventral margin of the valves, small spines in the posterodorsal portion of the shell; with a lithodesma. Mantle: Mantle margin with two fused points, anteriorly forming a wide pedal gape and posteriorly forming the siphons; posteroventrally, mantle margin fusion formed by inner and middle folds (Type B) (Yonge, 1982); absence of a fourth pallial aperture. Siphons: Separated, different in size and outline; inhalant siphon, large, modified in a raptorial appendage, usually contracted into the pallial cavity; exhalant siphon short, tube-shaped; both surrounded at the base by a ring of ~ 50 smaller tentacles closest to the aperture and by ~ 60 bigger tentacles peripherally located. Ctenidia: Eulamellibranch, very reduced, non-plicate and horizontally aligned; complete, with two demibranchs. Labial palps: Non-lamellate, extremely complex, outer and inner palps medially fused forming two pouches or buccal sacs, one small anterior and another large posterior; unfused tips forming narrow fluted funnels laterally. Musculature: Posterior and anterior adductor muscles present and isomyarian; with posterior and anterior pedal retractor muscle; absence of taenioid muscle.	en	Machado, Fabrizio Marcondes, Passos, Flávio Dias, Giribet, Gonzalo (2019): The use of micro-computed tomography as a minimally invasive tool for anatomical study of bivalves (Mollusca: Bivalvia). Zoological Journal of the Linnean Society 186: 46-75
039A87863A30B924FC32F9F269D1FA24.taxon	description	(FIGS 8, 9) Description Shell: Oval, compressed, robust; external sculpture formed by prominent and irregularly spaced radial ribs; lunule deeply impressed; debris attached by the entire length of outer surface of the valves; lithodesma present. BIVALVES AND MICRO-COMPUTED TOMOGRAPHY 57 Mantle: Mantlemarginmostlyunfusedanteriorlyforming a large pedal aperture; posteriorly there is a ventral fusion forming the siphons; without a fourth pallial aperture. Siphons: Separated; inhalant siphon, muscular, short, thin, cone-shaped, contracted into the pallial cavity; exhalant, very small, barely visible; siphonal apertures surrounded at their base by siphonal tentacles, ~ 20 around the inhalant and three around the exhalant aperture. Ctenidia: Highly reduced, non-plicate and horizontally aligned; complete, with inner and reduced outer demibranchs, extending from mouth to ventral side of the exhalant aperture.	en	Machado, Fabrizio Marcondes, Passos, Flávio Dias, Giribet, Gonzalo (2019): The use of micro-computed tomography as a minimally invasive tool for anatomical study of bivalves (Mollusca: Bivalvia). Zoological Journal of the Linnean Society 186: 46-75
039A87863A37B925FF4EFE4A6C3AFD23.taxon	description	(FIGS 10, 11) Description Shell: Ovate-trigonal, inflated, thin, whitish, inaequilateral, slightly inaequivalve; posterior margin with a short rostrum; outer sculpture granulated with micro-pustules over the entire shell; without lithodesma. Mantle: Ventral mantle margin with one anteriorly wide pedal gape, extending from the anterior adductor until the inhalant siphon; without a fourth pallial aperture. Siphons: Separated, different in size and outline; inhalant siphon, large, modified in a raptorial appendage, typically retracted into the infra-septal chamber; exhalant siphon short, cone-like and everted in this specimen; both surrounded at the base by a ring of large siphonal tentacles, 12 around the inhalant and three around exhalant; debris attached to the siphonal walls. Septum: Thin, ventral surface with well-defined twopaired groups of slit-like branchial apertures, with no interfilamental connections; anterior group with four and posterior with five slits. Presence of a small and lobulate hollow sac in the posterior inner floor of the septum. L a b i a l p a l p s: N o n - l a m e l l a t e, f l a t t e n e d a n d asymmetrical with anterior labial palps large and posterior labial palps small. Musculature: Posterior and anterior adductor muscles present and isomyarian; with posterior and anterior pedal and septal retractor muscles; lateral septal muscles not visible in this specimen; taenioid muscle absent. Foot: Large and elongated; absence of pedal groove and byssal thread. Digestive system: The funnel-shaped mouth opens into a thick, short and muscular oesophagus that enters the anterodorsal portion of the stomach; with a sphincter between oesophagus and stomach opening; stomach large, rounded, internal grooves not visible into the gastric chamber; stomach connected to the short and small crystalline style sac located on the median portion of the stomach floor; no prey observed inside the stomach; stomach surrounded dorsally and anteriorly by the gonads and digestive gland; two gastric caeca observed in the digestive gland; crystalline style sac conjoined with the anterior portion of the midgut; crystalline style present; pericardium / heart surround the rectum / hindgut; hindgut passes above the kidney. Reproductive system: Hermaphroditic, ovary and testis well visible; ovary closely associated to the digestive gland cover the roof and the posterior wall of the stomach; the testis lie ventral to the ovary and consist of a pair of large lobulate sacs. Nervous system: With circum-oesophagic, pedal and visceral ganglia observed.	en	Machado, Fabrizio Marcondes, Passos, Flávio Dias, Giribet, Gonzalo (2019): The use of micro-computed tomography as a minimally invasive tool for anatomical study of bivalves (Mollusca: Bivalvia). Zoological Journal of the Linnean Society 186: 46-75
039A87863A37B938FC94FCE66A74FF71.taxon	description	(FIGS 12, 13) Description Shell: Ovate, relatively thick, inflated, equivalve and approximately equilateral; with a brownish periostracum and sand grains covering the shell; without lithodesma. Mantle: Ventral mantle margin with one anterior and wide pedal gape, extending from the anterior adductor until two-thirds of the full length of ventral margin; posteroventral mantle margin fusion formed by inner folds (Type A) (Yonge, 1982); without a fourth pallial aperture. Siphons: Separated, different in size and outline; inhalant siphon large, modified in a raptorial appendage, typically retracted into the infra-septal chamber when the living animal is at rest or, in museum specimens, due to the alcohol contraction; the inverted inhalant siphon can also be referred to in the literature as a siphonal cowl (hood) or branchial valve, the latter considered a misinterpretation (Pelseneer, 1911; Yonge 1928, Bernard, 1974, Morton, 1981); exhalant siphon short, cone-like; siphons surrounded at the base by a ring of large siphonal tentacles, ten around the inhalant and three around exhalant; presence of ~ 15 siphonal papillae between the siphonal tentacles. Septum: Thin, transparent, perforated by three rows of grouped pores without interfilamental connections, comprising six pairs of pores anteriorly, five to six in the middle and four posteriorly. Presence of a swollen, hollow and bilobate sac in the posterior inner floor of the septum. Labial palps: Non-lamellate and asymmetric with anterior labial palps well-developed, large, cup-shaped and posterior palps reduced, almost imperceptible in the 3 D reconstructions. Musculature: Posterior and anterior adductor muscles present, isomyarian; with posterior and anterior pedal and septal retractor muscles; lateral septal muscles and taenioid muscle absent. Foot: Large and elongated; without pedal groove and byssal thread. Digestive system: The funnel-shaped mouth opens into a thick, short and muscular oesophagus that enters the anterodorsal portion of the stomach; no sphincter was observed between oesophagus and stomach opening; stomach large, rounded, with longitudinal deep grooves in the posterodorsal and anteroventral walls; with prey inside the gastric chamber (maybe ostracod and copepods); stomach connected to the short and small crystalline style sac located at the ventroanterior portion of the stomach floor; stomach surrounded dorsally and anteriorly by the gonads and digestive gland; crystalline style sac conjoined with an anterior mid gut; crystalline style not visible; pericardium / heart surround the rectum / hindgut; hindgut passes above the kidney. Organs of visceral mass: Haemocoel spaces present in the dorsoposterior portion of the visceral mass. Reproductive system: Hermaphroditic; ovary and testis well visible, closely associated to the digestive gland; ovary dorsally located and testis in the anteroventral portion of the visceral mass, close to the lateral wall of the stomach. Nervous system: Circum-oesophagic, pedal and visceral ganglia observed. 62 F. M. MACHADO ET AL.	en	Machado, Fabrizio Marcondes, Passos, Flávio Dias, Giribet, Gonzalo (2019): The use of micro-computed tomography as a minimally invasive tool for anatomical study of bivalves (Mollusca: Bivalvia). Zoological Journal of the Linnean Society 186: 46-75
039A87863A2AB93AFF52F923697AF9CD.taxon	description	(FIGS 14, 15) Description Shell: Ovate-trigonal, thin, inflated, slightly translucid, with prominent umbones, inflated; sculpture of radial lines of micro-pustules for the entire ventral surface of the valves; without lithodesma. Mantle: Ventral mantle margin with one anteriorly wide pedal gape extending from the anterior adductor until the inhalant siphon; without a fourth pallial aperture. Siphons: Separated, different in size and outline; inhalant siphon, large, modified in a raptorial appendage, typically retracted into the infra-septal chamber; exhalant siphon short, cone-like and everted in our specimen; both surrounded at the base by a ring of siphonal tentacles, ~ ten around the inhalant and ~ three around exhalant. Septum: Thin, perforated by three rows of grouped pores without interfilamental connections, the two anterior groups lie in a similar position to those of Cetoconcha spinosula comb. nov. and the third and smallest group lies behind the posterior septal muscles; bilobate hollow sac not observed in the posterior inner septal floor. With nine pairs of pores in the anterior group, five in the middle and three in the posterior group. Labial palps: Non-lamellate and asymmetrical with anterior labial palps large, thin (probably contracted), cup-shaped and the posterior labial palps small. Musculature: Posterior and anterior adductor muscles present and isomyarian; with posterior and anterior pedal and septal retractor muscles; prominent lateral septal muscles present; taenioid muscle absent. Foot: Large, pedal groove not observed, without byssal thread. Digestive system: The funnel-shaped mouth opens into a thick and muscular oesophagus that enters the anterodorsal portion of the stomach; stomach large, rounded, with longitudinal deep internal grooves in the dorsal wall, connected to the short and small crystalline style sac located in the median portion of the stomach floor; prey observed inside the stomach (ostracod: Fig. 14 A 2); stomach surrounded dorsally and 64 F. M. MACHADO ET AL. anteriorly by gonads and digestive gland; crystalline style sac not visible in this specimen. Reproductive system: May be dioecious, only ovary is visible in our specimen; ovary closely associated to the digestive gland, covers the roof of the stomach. Nervous system: only the visceral ganglia were observed.	en	Machado, Fabrizio Marcondes, Passos, Flávio Dias, Giribet, Gonzalo (2019): The use of micro-computed tomography as a minimally invasive tool for anatomical study of bivalves (Mollusca: Bivalvia). Zoological Journal of the Linnean Society 186: 46-75
039A87863A28B93CFF53F91B6C8FF8F8.taxon	description	(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. 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. 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 15 B, F, 16 D, 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.	en	Machado, Fabrizio Marcondes, Passos, Flávio Dias, Giribet, Gonzalo (2019): The use of micro-computed tomography as a minimally invasive tool for anatomical study of bivalves (Mollusca: Bivalvia). Zoological Journal of the Linnean Society 186: 46-75
