NMITA:Neogene Marine Biota of Tropical America



Bairdiella aff. ronchus (Cuvier, 1830)



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: rhomboidal, pointed posteriorly;
    Thickness: thick;
    Form: -Mesial slightly convex;
    Form: -Lateral convex;
    Dorsal margin: slightly angular and entire;
    Dorsal margin sculpture: sharply pre-dorsal spine and a deep notch in the anterior area of the dorsal margin;
    Ventral margin: slightly rounded;
    Posterior margin: sharply pointed in a prominent dome;
    Sulcus acusticus: ostial, heterosulcoid;
    Colliculum: heteromorph, low anterior and indistinct posterior colliculi;
    Pseudocolliculum: absent;
    Ostium: ovoid, in vertical position;
    Cauda: deep and wide, strongly flexed, ending close to ventral margin;
    Ostio-caudal differentiation: dorso-ventrally constricted;
    Collum: absent;
    Crista superior: poorly developed over ostium, ridge-like over cauda;
    Crista inferior: poorly developed under ostium, well developed along the entire cauda;
    Dorsal depression: very narrow and elongate;
    Ventral depression: absent;
    Rostrum: reduced;
    Antirostrum: sharply pointed;
    Excisura: moderately wide, notch absent;
Distribution:
    Late Pliocene: Rio Banano Fm., Limon, Costa Rica;

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