Sous-embranchement (subphylum) des Rhynchonelliformea
Classe des Rhynchonellata
Ordre des Terebratulida
Sous-Ordre des Terebratellidina
Super-famille des Platidoidea


Genus Platidia Costa, 1852

[Type species= Orthis anomioides Scacchi & Philippi, 1844 in Philippi, 1844 (p. 69)]
Synonyms : Morrisia Davidson, 1852, Platydia Seguenza (1870)

Small, subcircular to subquadrate in outline, planoconvex, thin shelled, semitransparent; smooth, or with radiating lines or spinules on ventral valve; hinge line wide, foramen large, amphithyrid; deltidial plates very narrow, disjunct. Pedicle collar short, sessile; hinge teeth with narrow dental plates and grooved, swollen bases; short ventral myophragm. Cardinal process absent; inner socket ridges strong; outer socket ridges narrow; no hinge plates; septal pillar located directly anterior to large amphithyrid pedicle embayment, bladelike and leaning anteriorly proximally but posteriorly deflected distally and terminating in a pair of posteriorly directed, Ushaped septal flanges; crura long and slender with short processes, descending branches strongly arcuate, uniting medianly with lateral flanks of Ushaped septal flanges.
Lophophore zygolophous.

Danian - Present

Diagnosis from volume 5 of the
Treatise on Invertebrate Paleontology (2006)

Extant Species of Platidia
  • P. anomioides (Scacchi & Philippi, 1844 in Philippi, 1844)
  • P. clepsidra Cooper, 1973
  • ? P. concentrica Zezina, 1980 > see P. anomioides
  • Diagnosis

    Platidia anomioides   (Scacchi & Philippi, 1844 in Philippi 1844)

    Type locality: Sicily [*]
    Depth range: 8 - 2289 m

    Orthis anomioides Scacchi & Philippi, 1844
    Terebratula appressa Forbes, 1844
    Platidia anomioides Costa, 1852
    Platydia anomioides Costa, 1852
    Morrisia anomioides Davidson, 1853
    Platidia davidsoni (Deslongchamps, 1855)
    Platidia marionensis Cooper, 1981
    Amphithyris sp Simões & Kowalewski 2000
    Amphithyris sp Simões 2000
    ? Platidia concentrica Zezina, 1980
    Terebratula seminulum Philippi, 1836 [**]

    Diagnosis - (Álvarez & Emig, 2005)

    Concha blanquecina o marrón claro, más o menos translucida, subrectangular, de casi circular a transversalmente ovalada, plano o cóncavo convexa, Valva dorsal más o menos irregular. Internamente, la valva ventral posee unos dientes cardinales pequeños y un septo medio corto y grueso, que se extiende aproximadamente 1/6 de la longitud de la valva, La valva dorsal carece de proceso cardinal; ramas descendentes del braquidio completas y ramas ascendentes, divergentes y muy cortas, surgiendo de! ápice del septo medio.

    [*] Type locality of P. davisdoni: off Tunis (Tunisia), synonym described by Eudes-Deslongchamps (1855, p. 443).

    [**] or of Joania cordata - Type locality: Trapani, Sicily, Italy.

    South of Malta (Mediterranean Sea):
    st. 29, Medicor cruise, R/V Urania, 473-453 m, 35°30'50.91N, 14°06'22.3E.
    © H. Zibrowius