NMITA:Neogene Marine Biota of Tropical America



Electrona rissoi (Cocco, 1829)



Specimen details:
 Sample Number: PPP2572
Type Status: nontype
Scale Bar is 1 mm
Type: SEM
Orientation: mesial
Locality: Cubagua, Cubagua, Venezuela

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Morphologic Description:

    Otolith shape: discoid, may be somewhat tall;
    Thickness: moderate;
    Form: -Lateral slightly convex;
    Dorsal margin sculpture: slightly irregular;
    Posterior margin: rounded and crenate or slightly irregular;
    Colliculum: approximately homomorph, colliculi similar sized;
    Ostium: approximately oval, poorly defined very low colliculum;
    Pseudocolliculum: present, very close to, and as long as, posterior colliculum;
    Antirostrum: rounded or pointed;
    Rostrum: short broad and sharply;
    Ventral depression: absent, shallow groove in mid-area;
    Dorsal depression: shallow, oval and large;
    Crista inferior: poorly developed along entire sulcus but may have low ridge under cauda;
    Crista superior: short, low ridge from mid-ostium to mid-cauda, poorly developed elsewhere, absent at cauda tip;
    Collum: absent;
    Ostio-caudal differentiation: slightly ventrally constricted;
    Excisura: moderate, notch shallow, angle acute;
    Cauda: approximately oblong, equal in width to ostium;
    Sulcus acusticus: ostial, approximately homosulcoid;
    Ventral margin: well rounded and crenulate;
    Dorsal margin: rounded or flattened,;
    Form: -Mesial slightly convex;
Distribution:
    Early Pliocene: Cubagua Fm., Cubagua, Venezuela;

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