NMITA:Neogene Marine Biota of Tropical America

Isopisthus renifer (Jordan & Gilbert, 1881)

Specimen details:
Sample Number: PPP1727
Type Status: nontype
Scale Bar is 1 mm
Type: SEM
Orientation: mesial
Locality: Limon, Limon, Costa Rica

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Morphologic Description:

    Otolith shape: becoming subrectangular;
    Posterior margin: straight and slightly irregular;
    Ventral margin: slightly rounded and entire;
    Excisura: narrow, notch absent;
    Antirostrum: reduced;
    Rostrum: reduced;
    Ventral depression: absent;
    Dorsal depression: shallow and elongate;
    Crista inferior: poorly developed under ostium, moderately well developed under cauda;
    Crista superior: poorly developed over ostium, ridge-like over cauda;
    Collum: absent;
    Ostio-caudal differentiation: dorso-ventrally constricted;
    Cauda: straight and narrow, tip gently bent in ventral direction;
    Ostium: moderate and subrectangular;
    Pseudocolliculum: absent;
    Colliculum: heteromorph, low anterior and indistinct posterior colliculi;
    Sulcus acusticus: ostial, heterosulcoid;
    Thickness: moderately thick;
    Form: -Lateral convex;
    Dorsal margin: slightly straight, with an obtuse postero-dorsal angle;
    Dorsal margin sculpture: slightly entire;
    Form: -Mesial slightly convex;
    Late Pliocene: Rio Banano Fm., Limon, Costa Rica;

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