Bivalvia, Linnaeus, 1758
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publication ID |
https://doi.org/10.11606/1807-0205/2024.64.031 |
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persistent identifier |
https://treatment.plazi.org/id/4008878E-FFFE-A81D-8C34-DB36FE80FC61 |
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treatment provided by |
Felipe |
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scientific name |
Bivalvia |
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Class Bivalvia View in CoL Subclass“Protobranchia” (grade)
Order Nuculida Superfamily Nuculoidea Family Nuculidae Genus Brevinucula Thiele, 1934
Brevinucula overa , new species ( Fig. 38 View Figure 38 ) https://zoobank.org/ 5EEC0AAF-6447-402B-8FAF-8E04BDE6FDE5
Types: Holotype MZSP 166720 View Materials , shell . Paratype: MZSP 166721, 1 spm, MZSP 166628, 25 shells, 37 valves, MNHN-IM-2000-39809, 2 shells, 6 valves, MNRJ, 1 shell, 2 valves, all from type locality.
Type locality: BRAZIL. Espírito Santo ; ItaÚnas, off, slope of Abrolhos, 19°40.6′S 37°48.1′W, 790-940 m [ MD55 sta. CB77 , 27.v.1987] GoogleMaps .
Diagnosis: Species from off SE Brazil with umbonal angulation of ~90°. Shell edges flattened. Hinge with 8-9 anterior and 6 posterior teeth.
Description: Shell of ~ 5 mm; shape oval, pointed dorsally; as long as tall up to with length ~92% of height; walls slightly thick. Umbo relatively pointed, prominent, with protruded, rounded prodissoconch flanked by shallow, weak structure ( Fig. 38E, J View Figure 38 ); prodissoconch of 0.45 mm. Umbo erect, slightly dislocated posteriorly, with umbonal angulation of ~90°. Anterior and posterior umbonal edges almost symmetrical, posterior edge slightly shorter and straight; anterior edge longer and slightly convex; ventral edge widely rounded ( Fig. 38 View Figure 38 A-B, D-J) or with weak, blunt posterior beak. Maximum inflation ~65% of length ( Fig. 38C View Figure 38 ). outer surface glossy, shining, bearing only weak growth lines. Color white ( Fig. 38 View Figure 38 H-J), with fresh specimens with thin, light brown periostracum, deciduous in oldest portions ( Fig. 38A, B, E, F View Figure 38 ). Ligament with inner portion thick, perpendicular, restricted to sub-umbonal region ( Fig. 38D, G View Figure 38 : li). Hinge occupying entire dorsal edge ( Fig. 38D, G, H, I View Figure 38 ), thicker regions occupying ~13% of shell height; peri-ligament potion lacking teeth; from this region both anterior and posterior series of teeth gradually growing towards edges, becoming wider in subterminal region in both sides; 8-9 teeth in slightly curved, longer anterior set; 6 teeth in slightly shorter, straight posterior. Both adductor muscle scars rounded, located ventrally to both ends of hinge, anteri- or scar slightly longer dorso-ventrally ( Fig. 38H, I View Figure 38 ); pallial line weakly visible parallel to ventral edge ( Fig. 38I View Figure 38 ).
Etymology: The specific epithet is based on the Guarany language word overa , meaning bright, shining, an allusion to the glossy surface of the shell.
Distribution: Off Espírito Santo to Rio de Janeiro coasts, continental slope.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.