NMITA:Neogene Marine Biota of Tropical America



Lactarius aff. atlanticus (Steubaut & Jonet, 1982)



Specimen details:
 Sample Number: PPP2540
Type Status: nontype
Scale Bar is 1 mm
Type: SEM
Orientation: mesial
Locality: Paraguana, Paraguana, Venezuela

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Morphologic Description:

    Otolith shape: rhomboidal;
    Posterior margin: oblique and rounded, sinuate to irregular;
    Ventral margin: rounded and sinuate to irregular;
    Crista inferior: poorly developed under ostium, well developed under cauda;
    Crista superior: poorly developed over anterior ostium and near tip, ridge-like along anterior cauda, absent at tip;
    Collum: absent;
    Ostio-caudal differentiation: dorso-ventrally constricted;
    Cauda: short, narrow and almost straight, tip indistinct, ends open to posterior margin;
    Ostium: oval, slightly angled dorsally;
    Pseudocolliculum: absent;
    Colliculum: heteromorph, anterior colliculum oval and raised, posterior low;
    Excisura: moderate, notch very shallow, angle wide;
    Antirostrum: minute and sharply rounded;
    Rostrum: short, broad and sharply rounded, may have slight dorsal flexion;
    Ventral depression: absent;
    Dorsal depression: oval, above anterior cauda;
    Sulcus acusticus: ostial, heterosulcoid;
    Thickness: moderately thin;
    Form: -Lateral concave;
    Dorsal margin: slightly rounded;
    Dorsal margin sculpture: sinuate to irregular;
    Form: -Mesial convex;
Distribution:
    Early Miocene: Cantaure Fm., Paraguana, Venezuela;

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